Fórum pridal Tomas55555, 11. 11. 2019 19:34 do kategórie Filozofovanie. Pozri ďalšie diskusie tohto používateľa >

Svedectvá o nebi a pekle

Názory k téme

  1. 1
    Thunderstorm

    15 ročné dievča
    devil's little sister

    (letim)
  2. 2
    Tomas55555

    24 ročný chalan

    Existuju desattisíce kresťanských svedectiev ľudí ktorí mali videnie neba/pekla. Boh im sprostredkoval tento zážitok, ocitli sa v nebi/pekle, no vrátili sa odtiaľ naspäť aby nám podali svoje svedectvo. Tých zážitkov je naozaj obrovské množstvo, len ja sám som zatiaľ na internete našiel okolo 134 takýchto svedectiev ( Dole uvádzam zoznam týchto svedectiev i s linkami).
    Co si o týchto svedectvách myslíte ? Mali všetci títo ludia len halucinácie, alebo všetci títo ludia klamú ? Alebo sa jedná o reálne príbehy ? Ja osobne si myslím že ide o reálne javy. Zážitky sú velmi prepracované než aby mohlo ísť o nejakú chaotickú halucináciu a počet takýchto zážitkov je obrovský, takže je velmi nepravdepodobné že si to všetci vymysleli a že ani jeden z týchto opisovaných zážitkov nie je pravdivý.

    Dole uvádzam osoby (134 osôb) ktoré takýto zážitok opísali a odkaz na ich svedectvá :


    1)Angelica Zambrano
    2)Bernarda Fernandez
    3)Bill Wiese
    4)Curtis Kelley
    5)Carmelo Brenes
    6)Choo Thomas
    7)Dr. Ouwuor
    8)Kenneth Hagin
    9)Mario Martinez
    10)Mary Baxter
    11)Michael Yeager
    12)Ron Regan
    13)Thomas Sambo
    14)Victoria Nehale
    http://www.wonderreality.org/wp- content/uploads/2017/12/Hell-13-Testimon ies-for-WR-website.pdf
    ................ ........................................ ........................................ .
    15)Marietta Davis
    16)Rebecca Springer
    17)Lorraine Tutmare
    18)George Ritchie
    19)Betty Malz
    20)Deborah O Donnell
    21)Gary Wood
    22)Richard Eby
    23)Rhoda Jubilee Mitchell
    24)Valvita Jones
    25)Roberts Liardon
    26)Richard Sigmund
    27)Roland Buck
    28)Gerald Landry
    29)Ian McCormick
    30)Yong Gyu Park
    31)Jesse Duplantis
    32)Don Diper
    33)Maurice Maelo
    34)Khalida Wukawitz
    35)Bill Smith
    36)Mary Neal
    37)David Taylor
    38)Michael McCormick
    39)Colton Burpo
    40)Dean Braxton
    41)Marvin Besteman
    42)Eben Alexander
    43)Crystal McVea
    44)Bob Misst
    http://www.wonderreality.org/wp-c ontent/uploads/2017/12/Heaven-33-Stories -version-for-WR-website.pdf
    ........... ........................................ ........................................ ........................................ ....
    45)Diego Ortiz
    https://www.youtube.com/watch?v=2l-lKa BrVH4
    46)Percy Collett
    https://www.youtube.com/watch?v =HNZIN1te_hc
    47)Tyrone Wiliams
    https://www.youtube.com/watch?v =X5C-hxqpfjE
    48)Cesar Sandoval
    https://www.youtube.com/watch?v=q8JL8a FyVsg
    49)Bryan Melvin
    https://www.youtube.com/watch?v= U1JQg4tQED0
    50)John Lopez
    https://www.youtube.com/watch?v=1 mcJkYpSTNM
    51)Morris Cerullo
    https://divinekingdom.wordpress .com/2015/03/09/i-saw-the-very-flames-of -hell-testimony-of-evangelist-morris-cer ullo/
    52)Adelaida De Carillo
    https://www.facebook.com/notes/ yves-nahishakiye/heaven-and-hell-are-so- real-adelaida-de-carrillo/34958182840752 2/
    53)Kristen Coleman
    https://www.youtube.com/watch?v=6JJXnB Smcx0
    54)James Durham
    https://www.youtube.com/watch?v= pp4dAAcrge8
    55)Gary & Shirley Kivelowitz
    https://www.youtube.com/watc h?v=viRrJlvOop0
    56)Laurie Ditto
    https://www.youtube.com/watch?v=q JP0iJ1Zbjg
    57)John Burke
    https://www.youtube.com/watch?v=a rq7GbLNQnA
    58)Ana Werner
    https://www.youtube.com/watch?v=B84_Gb E_3wM
    59)Shane Warren
    https://www.youtube.com/watch?v= ZnrpHgD5YhM
    60)Kevin Zadai
    https://www.youtube.com/watch?v=1 1k_LkzUjHI
    61)Jeff Jansen
    https://www.youtube.com/watch?v= 3M3cdXhWfTM
    62)Tony Kemp
    https://www.youtube.com/watch?v=Ag MpGmdl_4w
    63)Eddie James
    https://www.youtube.com/watch?v=N UyaShE1fOs
    64)Daniel Ekechukwu
    https://www.youtube.com/watch ?v=nzx4nyZKc2U
    65)Joe Hadwin
    https://www.youtube.com/watch?v= IOhOynR9Jxg
    66)Nancy Chandy
    https://www.youtube.com/watch?v= -FuIuxjHhAo
    https://sk.pinterest.com/ph ilpotth2/heaven-hell-testimonies/
    67)At torney Jeffrey
    https://www.youtube.com/watch?v =-FuIuxjHhAo
    68)Jordan Samuel
    https://www.youtube.com/watch?v= -FuIuxjHhAo
    69)John Lake
    70)Dudley Danielson
    71)Marvin Ford
    72)Aline Baxley
    73)Benny Hinn
    https://www.wayoflife.org/database /beware_of_alleged_trips_to_heaven.html

    74)Katt Kerr
    75)Don Piper
    76)Robin Harfouche
    77)Mahesh Chavda
    https://www.godisreal.today/proo f-of-heaven/
    78)Oden Hetrik
    https://www.youtube.com/watch?v= G5QBZU870Ms&list=PLI4v9HkWNA453q92fp 81_hWphzIU8OL2u&index=4&t=0s
    79 )Joshua Munguti
    https://www.christiantruthcente r.com/my-visit-to-heaven/
    80)lyah Melea
    http://www.theheavenandhell.net/5 -minutes-in-hell-2nd-testimony-by-melea- philippines/
    81)Emmanuel Senayon
    http://www.theheavenandhell.net /the-mystery-of-heaven-and-hell-by-emman uel-senayon-from-nigeria/
    82)John Bunyan
    http://www.theheavenandhell.net/vision s-of-heaven-and-hell-by-john-bunyan/
    83 )Shinee Moa
    https://www.youtube.com/watch?v=OUv DeiUEGIc
    84)Ps Yong Doo Kim
    http://www.theheavenandhell.net/vis ion-of-pastors-and-christians-in-hell-by -ps-yong-doo-kim/
    85)Fatuma Shubisa
    http://www.theheavenandhell.net /fatuma-shubisa-twelve-hours-in-heaven/

    86)Yvonne Sklar
    http://www.theheavenandhell.net/b eing-face-to-face-with-god/
    87)Julie Papievis
    http://www.theheavenandhell.ne t/julie-papievis-to-heaven-and-back/
    88 )E. Dixon
    http://www.theheavenandhell.net/a -gate-of-hell-queen-e-dixon/
    89)Peter Panagore
    https://www.youtube.com/watch? v=NnzpqUa7yKg
    90)Ann Muthoni
    https://www.seekandyeshallfind.info/si ngle-post/2018/08/07/Heaven-and-hell-tes timony-from-sister-Ann-Muthoni-Kenya
    91 )Rachael Mushala Chisulo
    https://www.seekandyeshallfind.info/si ngle-post/2019/03/15/I-went-to-hell-for- blowing-my-hair-Outward-inner-holiness-a -must-by-Rachael-Mushala-Chisulo
    92)Gab riel Doufle
    https://www.seekandyeshallfind.i nfo/single-post/2019/04/21/DIVINE-REVELA TION-OF-HELL-AND-HEAVEN-TO-GABRIEL-DOUFL E-OF-TOGO-IN-09-DECEMBER-2011
    93)Zipora h Mushala
    https://www.seekandyeshallfind. info/single-post/2018/03/07/HELL-FIRE-AW AITING-FOR-THOSE-WHO-INDULGE-IN-DRINKING -OF-ALCOHOL-AND-SMOKING-OF-CIGARETTES
    9 4)Emmanuel Agyarko
    https://www.seekandyeshallfind. info/single-post/2018/03/07/HELL-FIRE-AW AITING-FOR-THOSE-WHO-INDULGE-IN-DRINKING -OF-ALCOHOL-AND-SMOKING-OF-CIGARETTES
    9 5)Ayodelle Sawyer
    https://www.seekandyeshallfind.i nfo/single-post/2018/03/07/HELL-FIRE-AWA ITING-FOR-THOSE-WHO-INDULGE-IN-DRINKING- OF-ALCOHOL-AND-SMOKING-OF-CIGARETTES
    96 )Baek Bong-Nyo
    https://www.seekandyeshallfind .info/single-post/2018/03/07/HELL-FIRE-A WAITING-FOR-THOSE-WHO-INDULGE-IN-DRINKIN G-OF-ALCOHOL-AND-SMOKING-OF-CIGARETTES
    97)Lee, Haak-Sung
    https://www.seekandyeshallfind.info/si ngle-post/2018/03/07/HELL-FIRE-AWAITING- FOR-https://www.seekandyeshallfind.info/ single-post/2018/03/07/HELL-FIRE-AWAITIN G-FOR-THOSE-WHO-INDULGE-IN-DRINKING-OF-A LCOHOL-AND-SMOKING-OF-CIGARETTESTHOSE-WH O-INDULGE-IN-DRINKING-OF-ALCOHOL-AND-SMO KING-OF-CIGARETTES
    98)Linda Ngaujah
    https://www.seekandyeshallfind. info/blog/2017/10/18/messages-from-the-l ord-to-catholics-worshipping-idols-statu es
    99)Samuel Oghenetega
    https://www.seekandyeshallfi nd.info/blog/2017/10/18/messages-from-th e-lord-to-catholics-worshipping-idols-st atues
    100)Sabino Barientos
    https://www.youtube.com/watch ?v=KJ8n098BOjw
    101)bakajika muana Nkuba
    https://www.seekandyeshallfind.in fo/blog/2017/10/18/messages-from-the-lor d-to-catholics-worshipping-idols-statues
    102)Lunathi Zamla
    https://www.seekandyeshallfind.in fo/single-post/2019/05/03/REALITY-OF-HEA VEN-AND-HELL-BY-SISTER-LUNATHI-ZAMLA-FRO M-SOUTH-AFRICA
    103)Thomas niditauae
    https://www.youtube.com/watch ?v=l8vpp2aze9M
    104)Philip Mantofa
    https://www.youtube.com/watch?v =C64h7xVVL4w
    105)Ron Stewart
    https://www.youtube.com/watch?v =k-H2re-bFfc
    106)Ron Ogren
    https://www.youtube.com/watch?v=p dnBcq6zZnA
    107)Tony Alamo
    http://www.alamoministries.com/Ne wsletters/06000.pdf
    108)Jordan Cook
    https://www.youtube.com/watch?v=uQ kMnW2JgjY
    109)Reggie Anderson
    https://www.youtube.com/watch? v=AXzVvNXiRn4
    110)Kevin Basconi
    https://www.youtube.com/watch?v =YS4HSKmx728
    111)Jack Sheffield
    https://www.youtube.com/watch?v=1uo4lQ X6Bo8
    112)Howard Pittman
    http://www.heavenvisit.net/howa rd-pittman.html
    113)Ron Pettey
    http://www.heavenvisit.net/ron-p ettey.html
    114)Carl Knighton
    http://www.heavenvisit.net/car l-knighton.html
    115)Athet Pyan Shinthaw Paul
    http://www.heavenvisit.net/athet-p yan-shinthaw-paul.html
    116)Loretta Blasingame
    http://www.heavenvisit.net/l oretta-blasingame.html
    117)Sarah Boyanga
    http://www.heavenvisit.net/sara h-boyanga.html
    118)Sori Park
    http://www.heavenvisit.net/sori-pa rk.html
    119)Young Moon Park
    http://www.heavenvisit.net/young-m oon-park.html
    120)Janet Baldera
    http://www.soonrapture.com/jane t-balderas.html
    121)Howard Storm
    https://hellandheaventestimonies. wordpress.com/2010/10/23/hell/
    122)Sene ca Sodi
    https://hellandheaventestimonies.w ordpress.com/2010/11/28/heaven/#_Seneca_ Sodi’s_testimony
    123)Ricardo Cid
    https://hellandheaventestimonies.wo rdpress.com/2010/11/28/heaven/#_RICARDO_ CIDhttps://hellandheaventestimonies.word press.com/2010/11/28/heaven/#_RICARDO_CI D’S_TESTIMONY’S_TESTIMONY
    124) Kay Lynn Trimble
    http://www.theheavenandhell.net /testimony-of-mormon-lady-go-to-hell/
    1 25) Tamara Laroux
    https://youtu.be/QADzBe2TLZg
    126) Antje Harting
    http://www.theheavenandhell.net /i-saw-ellen-white-in-hell-the-founder-o f-seventh-day-adventist/
    127) Miguel Vásquez
    http://www.theheavenandhell.net/ex-cat holic-priest-testimony/
    128) Acevedo Hernandez
    https://z3news.com/w/evangelist-rodolf o-acevedo-hernandez-heaven-hell/
    129) Anna Rountree
    http://www.divinerevelations.i nfo/documents/the_heavens_opened/
    130) Jenifer Perez
    http://www.divinerevelations.info/docu ments/jennifer_perez/hell_is_real_i_went _there_jennifer_perez.htm
    131) Torben Søndergaard
    https://thelastref ormation.com/i-was-in-hell/
    132 ) Juan Hugo ( Juzna Afrika, cirkev nezistená, pravdepodobne protestant)
    https://iwenttoheavenmommy. wordpress.com/2013/09/05/i-went-to-heave n-mommy/
    133) Richard Antwi
    https://www.youtube.com/watch?v=M muYGPxCMzM
    134) Gracia Ayikoe
    https://kristelgarciano.wordpres s.com/2018/04/30/hell-testimony/
  3. 4
    Patrixo

    32 ročný muž
    Militantný slniečkar

    no to treba spraviť porjadni visluch v uňiverzitnej mučjarňi, to ňeňi ľen tak.. to može bárzkdo povedať
  4. 5
    Firestorm

    30 ročný muž
    Bratislava

    Neni o čom
  5. 6
    Patrixo

    32 ročný muž
    Militantný slniečkar

    aľe peklo existuje, ľebo pan sudruh čižnar povedali že ho rozpruďja, tak to tak musi byť keť pan prokurator take povije
  6. 7
    Mielikki

    hrá sa, že má 0 rokov
    Pani lesa

    nejedli tí ľudia plesnivý chlieb?
  7. 8
    Tomas55555

    24 ročný chalan

    @mielikki Nejedli. Prečo by mali jesť ?
  8. 9
    Patrixo

    32 ročný muž
    Militantný slniečkar

    @mielikki jasne ze jedli
  9. 10
    Dreyjir

    22 ročné dievča
    [smutná]

    Styri roky som scrollovala skrze hnoj, aby som napisala, ze grckam, ked pocujem slovo "svedectvo"
  10. 11
    Darksider96

    23 ročný chalan
    Underworld

    @patrixo Myslím, že robiť si z neho srandu nie je vhodné keďže trpí zrejme nejakou poruchou osobnosti. Dávnejšie som s ním diskutoval celé dní v jeho fóre a pri konci som mal pocit, že trolluje, tak som poslal link na veľa jeho príspevkov z birdzu jednému známemu ktorý je spevák v mojom hudobnom projekte a študuje psychológiu a ten vravel, že by nedal ruku do ohňa za jeho duševné zdravie. Že vraj kľudne môže mať schizoidnú alebo schizotypovú poruchu. Navyše to si už všimli aj ostatní birdzáci :smile:
  11. 12
    Patrixo

    32 ročný muž
    Militantný slniečkar

    @darksider96 aaa shit.. ok, uz som ticho
  12. 13
    Tomas55555

    24 ročný chalan

    @darksider96

    Môžem s istotou potvrdiť že žiadnou schizofreniou netrpím. Uviedol som dôkazy pre svoje argumenty a dal linky na svedectvá. Ale je mi jasné že ked nie sú protiargumenty tak sa schádza do vymyslených psychiatrickych diagnoz.
  13. 14
    Karlotiskot

    34 ročný ujo
    I'll Be In The Garage

    Nech sa páči. Tu máš protiargument, ktorý to všetko vysvetluje. Ale pre teba to bude dlhá cesta k pochopeniu, takže rovno si to prečítaj celé a pokračuj cez odkazy na rozne mozgove centrá.
    https://en.wikipedia.org/wiki/Brain

    Zmení ti to život viac jak posmrtný zážitok. Nemáš zač.
  14. 15
    Tomas55555

    24 ročný chalan

    @karlotiskot

    Prečítam si to celé a nakoniec zistím že ten protiargument sa tam nikde nenachádza.... Ak teda tomu rozumieš, tak mi sem priamo skopíruj citácie ktoré dokazujú tvoje tvrdenie.
  15. 16
    Salora

    tvári sa, že má 3 roky
    Oostende - Kappelmeister Birdzu

    akoze tych 134 ludi = obrovsky pocet zazitkov? (: pri pocete skoro 8 mld obyvatelov planety? (:
  16. 17
    Tomas55555

    24 ročný chalan

    @salora

    134 ľudí je len počet ludí ktoré sa len MNE osobne, ZATIAL podarilo na internete nájsť. Ak by som mal rátať aj svedectvá ktoré ešte len nájdem ( zatial hladám len zopár týždnov), a ktoré nie sú zverejnené na internete, ten počet by bol obrovský.
  17. 18
    Karlotiskot

    34 ročný ujo
    I'll Be In The Garage

    @tomas55555 Prisahám Bohu že nachádza! V keď sa dostaneš cez základ ku odkazom na amygdalu tuším. Ale nepreskakuj, inak to nepochopíš.
  18. 19
    Tomas55555

    24 ročný chalan

    @karlotiskot

    Lenže dôkazne bremeno je teraz na tebe. Ja som sem poskytol svedectvá a dal na nich odkazy ( nikoho som neodkazoval nech si tie svedectvá vygoogli sám) a ty teraz ked tvrdíš opak, tak dolož to a presne ukáž citácie ktoré dokazujú tvoje tvrdenie.
  19. 20
    Karlotiskot

    34 ročný ujo
    I'll Be In The Garage

    @tomas55555 Dokazne bremeno? Jebe ti na hlavu? Ty mrháš životom na to aby si si pred ludmi dokazoval, že neveríš pičovinám a nemrháš zbytočne život zopínaním rúk. Ja som sa len prišiel pobaviť, lebo stejnak je to jedno načo mrháme životmi.

    Proste čitaj, čítaj, pekne o mozgu a ja len trvám na to, že ak si raz o ňom čo to zistíš tak ti to zmení život. (nie zlepší ;) )
  20. 21
    Firestorm

    30 ročný muž
    Bratislava

    @tomas55555 Boh nie je.

    That's all folks !
  21. 22
    Tomas55555

    24 ročný chalan

    @karlotiskot Ok, rovno teda povedz na rovinu že protiargument neexistuje, respektíve ty o žiadnom takom nevieš, inak by si ho sem už dávno dal a nevyhováral sa.
  22. 23
    Karlotiskot

    34 ročný ujo
    I'll Be In The Garage

    @tomas55555 Ja t predsa vravím, že existuje. Staćí si naštudovať niečo o ľudskom mozgu. To že si piča, čo ohrnie nos nad informáciou o najdoležitejšom orgáne svojho tela, len aby sa nestretla s protiargumentom za to ja fakt nemožem ty dokazne vemeno.
  23. 25
    Xxar3s

    36 ročný ujo
    Bratislava

    @Tomas55555 On nepísal o schyzofrénii ale schyzoidnej poruche. Schyzoidná porucha je druh psychopatie. Pri ktorej sa dá žiť relatívne normálny život.

    Zatiaľ čo schyzofrénia je ťažká psychóza ktorá spôsobuje bludy, halucinácie a rozpad osobnosti. Tieto dve diagnózy majú podobný len názov inak, ale nemajú nič spoločné.

    Ale myslím že darksider si do teba potreboval len kopnúť pretože si kresťan a onm sa nedokáže povzniesť nad to že existujú ľudia ktorí majú iné názoryt ako on. Ja chápem prečo má darksider zášť ku kresťanom. Ale tým že bude na niekoho chŕliť žlč škodí len sám sebe.
  24. 26
    Tomas55555

    24 ročný chalan

    @karlotiskot Nehnevaj sa ale takto ako si to predstavuješ ty to nefunguje. Ziak ked niečomu nechápe a príde za učitelom, učitel mu to hned vysvetlí a nie že ho odkáže na cudzojazycnu niekolko desiatok stranovú literatúru.

    Týmto len dokazuješ že nič nevieš. Pýtam sa, je pre teba tak velmi náročné mi sem dať citácie ktoré dokazujú tvoje tvrdenie ?
  25. 27
    Karlotiskot

    34 ročný ujo
    I'll Be In The Garage

    @tomas55555 Si fakt piča? Čo máš v hlave nasraté, alebo si padol nosom na klinec? Ja niesom tvoj učitel to po prvé, a po druhé, keď od učiteľa chceš niečo vedieť tak presne to ti dá- literatúru.

    Tu máš svedectvá o Allahovy v posmrtnom živote, ktoré som našiel ZATIAL len JA za pol sekundy
    https://www.youtube.com/watch?v=5JA-LVPW-q8
    a od oblubeneho dokazovatela oneho sveta pre kresťanov (niekedy mi príde že čítali tak polku jednej jeho knihy) Morsea
    https://www.near-death.com/religion/islam.html

    Som rád, že ťa to určite presvedcilo prejsť na stranu moslimov. Takže tri krát za sebou len vyslovíš "Niet iného boha okrem Alláha a Mohamed je jeho prorok" a tvoj duševné bádanie je konečne na konci.

    Maa salama bratu. Allahu agbar.
  26. 28
    Tomas55555

    24 ročný chalan

    @karlotiskot

    Klames, učiteľ keď učí tak neodkazuje na cudziu literaturu. Ty si nikdy nechodil do školy, keď nevieš ako ucitelia svojich žiakov učia ? Keď si sa pýtal na biologii, odkazoval ťa učiteľ na cudzojazycnu literatúru alebo ti dal v triede vysvetlenie ?


    A vieš mi aj povedať o čom dotyčný vo videu hovorí ? Povedz mi obsah, pretože znova mám dojem že len bezmyslienkovite kopirujes z internetu prvú stránku ktorú nájdeš a v skutočnosti ani nevieš o čom to video je.
  27. 29
    Wistingher

    22 ročný chalan
    Bratislava

    V každom rohu sveta si ludia namyšlaju a vymyšlaju ine rozpravky aby zarobili a stiahli na seba pozornosť. ... Na filipínach sú kresťania silní, presvedčení... o pár km ďalej presvedčení moslimovia v Indonézii... každý si verí vo svojho boha... pre každého je ten jediný skutočný pravdivý... O pár tisíc km ďalej Čína kde máš Budhizmus , takisto India - Hinduizmus ... Každý z tych stoviek milionov su presvedčení a presviedčaní o svojej pravde a položili by za ňu možno aj život, pretože cely život žiju v tom presvedčení. ... Pozri sa na to z nadhľadom... Všetkých niekto manipuluje, a tí ľudia, čo veria v jedno, či druhé sú vlastne naivní a hlúpi. Miesto toho aby verili v seba, svoju silu, v to, čo dokáže človek urobiť, veria v niečo čo im niekto narozpráva, bez overenia, bez faktov, bez ničoho... ovplyvnení rodičmi v detstvách vo veku, keď uverili všetkému čo im hovorili... Takto si cirkev získava veriachich... takto manipuluje. Zmanipuluje deti, keď ešte nemajú vlastný názor.

    A o histórii náboženstiev a konfliktov nimi vyvolanými ani nehovorím...

    Fuj ...
  28. 30
    Karlotiskot

    34 ročný ujo
    I'll Be In The Garage

    @tomas55555 Neviem ako ty, nás učili z cudzej literatúry. Ale ok, ak si chodil do nejakého ústavu kde ste nič neštudovali iba počúvali učitela tak ako v poho. Predpokladám, źe ani bibliu si nakoniec nečítal, lebo ti stačilo aby ti ju vysvetlil niekto iný... To sú teda ťahy dpč.

    Ty si to pozeral? Ja teda nie. Vieš prečo? Lebo viem niečo málo o mozgu a posmrtné zážitky mi už viac vedomostí ako mám nemožu dať a tak nemusím plytvať životom na to, aby som zhromažďoval a skúmal už vysvetlené javy. Dať tak desať minút do každej výpovedi čo si akože "zhromaždil", tak za ten čas radšej opravím strechu na dome, alebo si budem kludne aj dva dni doberať drbka na birdzi, ktorí sa snaží presvedčiť trolla o tom, že dokázal existenciu Boha (ty píčo, dúfam, že aj ty počuješ ako pripičene znie čo robíš). Ale neboj, ja viem, že to stejnak robíš len kvoli svojej hlavičke. Kebyže sa pustiš do toho štúdia čo som ti odporúčal ušetril by si vela času vo svojom živote.
  29. 31
    Tomas55555

    24 ročný chalan

    @karlotiskot

    "Neviem ako ty, nás učili z cudzej literatúry."

    Iste, ked ste študovali napríklad kvadratické rovnice tak vám učitelia vôbec nič nevysvetlili, ale vás odkázali nech si to preštudujete na internetovej stránke xyz..... Takáto škola naozaj neexistuje, a ak existuje povedz jej názov, pojdem sa tam pozrieť.

    "Ale ok, ak si chodil do nejakého ústavu kde ste nič neštudovali iba počúvali učitela tak ako v poho."

    Zaujímavé ako vždy ked nemáš protiargument k téme sa schyluješ k nadávkam. Ked sme preberali nejakú tému, učitel to vždy vysvetlil, a ked nám to vysvetlil tak nám niekedy odporučil i nejakú stránku, no to bolo až vtedy ked sme už mali prebraté celé učivo, a na tej stránke sa to učivo len zopakovalo. Ale v drtivej väčšine prípadov nás na nič neodkazovali.
    ......................................................................................................................................
    A tu je ten problém, nepozeral si a takže ani nevieš o čom to je. Nevieš preto ani to že dotyčný tam hovoril o NDE a teda o zážitkoch klinickej smrti, ktoré su diametralne odlišné od krestanskych svedectiev ktoré som uviedol v mojom úvodnom komentári. Automaticky hodnotíš niečo čo nemáš dostatočne preštudované, a preto miešaš hrušky s jablkami, ale hlavne že sa tváriš ako tomu velmi rozumieš.

    Ok, otázka za 100 bodov, prečo majú ludia halucinácie kedy vidia Ježiša ktorí im ukáže a detailne popíše nebo/peklo ? Prečo nemajú trebárs nejaku chaotickú halucináciu, alebo halucináciu spagetoveho monstra ?
  30. 32
    Karlotiskot

    34 ročný ujo
    I'll Be In The Garage

    @tomas55555 Ale vieš o tom, že v učebniciach sú kvadratické rovnice vysvetlené? Moźno si mal do nich občas nazrieť :D

    Neplač prosím ťa o nadávkach a pičovinách. Ja som ti vravel že si ťa doberám, ty sa ma tu stále snažíš presvedčiť, že si dokázal existennciu Boha :D A jj hrajme sa, že nadávky sú zlo, vobec nie to slyzké pokusy o povyšovanie sa čo predvadzaš ty. Napľuľ by som ti do tváre už len za to, že si si v tomto smere dovolil hubu otvoriť na mňa ;)

    Otázka za 10000000 bodov Ako to, že sa ti snívajú veci, ktoré sa nikdy nestali? :O Vaaau určite preto, lebo ti anjelici zostupujú po večeroch pod viečka :D Fakt baviť sa s kktom čo nevie a nechce nič vedieť o hlave je dobré len na to si ho doberať a baviť sa na ňom. Najlepšie na tom ako mu povieš, že ho máš za piču a neberieš ho ani vážne, ale on sa snaží stále predstierať zmyslulpnú debatu, tým, že sa chytí každého frku a používa prirovnania, ktoré dávajú zmysel len v jeho hlave.
  31. 33
    Tomas55555

    24 ročný chalan

    @karlotiskot Lenže žiaci sa neučia z učebníc ale z toho ako im to učiteľ vysvetlí. Naozaj neviem o škole kde by sa učilo tak že učiteľ rozdá žiakom učebnice a povie im aby sa z nich učili a on si bude len sedieť a nič nerobiť. Na každej jednej škole najprv učivo vysvetlí učitel, a ked je učivo vysvetlené potom prichádzaju na rad príklady z učebnice.

    To vážne porovnávaš sny s krestanskymi zážitkami ? Rozdielov je tam viac než podobností. Sny si obvykle človek ani nepamätá, a ked si aj pamätá tak len velmi hmlisto, no pri krestanských zážitkov dotyčný dokáže opísať svoje svedectvo a zážitok v nebi/pekle do posledných detailov.

    Co sa snov týka, áno, snívaju sa aj sny ktoré sa nikdy nestali, a čo s tým akože teraz ? Zakaždým sa mi sníva iný sen, no pri krestanských zážitkov ide zakaždým o rovnaký scénar ( videnie neba/pekla). Ako teda vysvetlíš to že zakaždým ide o rovnaký scénar ? Ak sú krestanské svedectvá len sny, prečo nemá každý jeden krestan diametralne odlisny zážitok ?
    Další rozdiel je v tom, že kým sny vznikajú len počas spánku, krestanske zážitky neba/pekla často krát vznikajú u ludí ktorí sú v bdelom stave. Ako toto vysvetlíš ? Vysvetluj, (ak vieš vysvetliť).
  32. 34
    Karlotiskot

    34 ročný ujo
    I'll Be In The Garage

    @tomas55555 :D Ok tak ako hovoríš, ja som sa síce učil simultáne z učebníc a prednášok, nie som si celkom istý ako to može ísť bez štúdia, ale som rád, že ty si to zvládol. Nič to však nezmení na tom, že nie som tvoj učitel, ani že tu žiadne dokazne bremeno neexistuje, pretoze sme na birdzi, nie sudnej sieni ani na teologickej fakulte ak si si to doteraz nevsimol po mnohom mojom naznacovani :D

    Aha, cize ked je to nekretansky zazitok tak to nejde porovnat s tym krestanskym? A samozrejme ze porovnavam, pretoze v mozgu prebiehaju podobne procesy pri snoch ako pri halucinovani/posmrtnych zazitkoch-to by si vedel keby si miesto plakania o tom ako sa nespravam ako ucitel, alebo ako pravnik, radsej prestudoval nieco o tom mozgu :D Uz si mohol byt dost daleko bratu :D

    Vsetko na co sa pytas je objasnene ;) Fakt :D Uz si mohol byt aj pri teme halucinovania :D Ale jasne chapem. Ono halucinácie s kresťanskou tématikou s´vlastne znamenia, ale bez nej sú to len halucinácie :D
  33. 35
    Tomas55555

    24 ročný chalan

    @karlotiskot no zodpovies mi teda tie moje otázky alebo nie ? Lebo neustale odbocujes a nikdy mi nevieš odpovedať na to na čo som sa ťa pýtal, takže ?
  34. 36
    Karlotiskot

    34 ročný ujo
    I'll Be In The Garage

    @tomas55555 Šak som ti odpovedal :D Nevieš čítať, alebo máš piču miesto očí? :D Máš link na protiargument a vysvetlil som ti prečo zrovnávam sny a halucinácie/posmrtné zážitky.
    Tvoj jediný protiargument na to je, že čo ti v škole nevysvetlili tak to si nepochopil. :D Ja fakt nemozem za to ze si pica a neprecitas si nic o tom mozgu a o procesoch pri halucinaciach, ale ziadas tu odomna aby som ti to vysvetloval pri tom stejnak to budes citat ako z ucebnice :D :D Tak na, ked u si nevies otvorit ten link cele ti to tu postnem :D najprv prvu cast precitaj a potom mozes ist priamo na posmrtne zazitky, teorie, domnienky, ale aj realne vyskumy ci pozorovania v druhej casti. Nemas zac

    Brain
    From Wikipedia, the free encyclopedia
    Jump to navigationJump to search
    This article is about the brains of all types of animals, including humans. For information specific to the human brain, see Human brain. For other uses, see Brain (disambiguation) and Brains (disambiguation).
    Not to be confused with Brane or Brian.
    Brain
    Chimp Brain in a jar.jpg
    A common chimpanzee brain
    Identifiers
    MeSH D001921
    NeuroNames 21
    TA A14.1.03.001
    Anatomical terminology
    [edit on Wikidata]
    A brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head, usually close to the sensory organs for senses such as vision. It is the most complex organ in a vertebrate's body. In a human, the cerebral cortex contains approximately 14–16 billion neurons,[1] and the estimated number of neurons in the cerebellum is 55–70 billion.[2] Each neuron is connected by synapses to several thousand other neurons. These neurons communicate with one another by means of long protoplasmic fibers called axons, which carry trains of signal pulses called action potentials to distant parts of the brain or body targeting specific recipient cells.

    Physiologically, brains exert centralized control over a body's other organs. They act on the rest of the body both by generating patterns of muscle activity and by driving the secretion of chemicals called hormones. This centralized control allows rapid and coordinated responses to changes in the environment. Some basic types of responsiveness such as reflexes can be mediated by the spinal cord or peripheral ganglia, but sophisticated purposeful control of behavior based on complex sensory input requires the information integrating capabilities of a centralized brain.

    The operations of individual brain cells are now understood in considerable detail but the way they cooperate in ensembles of millions is yet to be solved.[3] Recent models in modern neuroscience treat the brain as a biological computer, very different in mechanism from an electronic computer, but similar in the sense that it acquires information from the surrounding world, stores it, and processes it in a variety of ways.

    This article compares the properties of brains across the entire range of animal species, with the greatest attention to vertebrates. It deals with the human brain insofar as it shares the properties of other brains. The ways in which the human brain differs from other brains are covered in the human brain article. Several topics that might be covered here are instead covered there because much more can be said about them in a human context. The most important is brain disease and the effects of brain damage, that are covered in the human brain article.


    Contents
    1 Anatomy
    1.1 Cellular structure
    1.2 Evolution
    2 Development
    3 Physiology
    3.1 Neurotransmitters and receptors
    3.2 Electrical activity
    3.3 Metabolism
    4 Function
    4.1 Perception
    4.2 Motor control
    4.3 Arousal
    4.4 Homeostasis
    4.5 Motivation
    4.6 Learning and memory
    5 Research
    5.1 History
    6 Other uses
    6.1 As food
    6.2 In rituals
    7 See also
    8 References
    9 External links
    Anatomy
    a blob with a blue patch in the center, surrounded by a white area, surrounded by a thin strip of dark-colored material
    Cross section of the olfactory bulb of a rat, stained in two different ways at the same time: one stain shows neuron cell bodies, the other shows receptors for the neurotransmitter GABA.
    The shape and size of the brain varies greatly between species, and identifying common features is often difficult.[4] Nevertheless, there are a number of principles of brain architecture that apply across a wide range of species.[5] Some aspects of brain structure are common to almost the entire range of animal species;[6] others distinguish "advanced" brains from more primitive ones, or distinguish vertebrates from invertebrates.[4]

    The simplest way to gain information about brain anatomy is by visual inspection, but many more sophisticated techniques have been developed. Brain tissue in its natural state is too soft to work with, but it can be hardened by immersion in alcohol or other fixatives, and then sliced apart for examination of the interior. Visually, the interior of the brain consists of areas of so-called grey matter, with a dark color, separated by areas of white matter, with a lighter color. Further information can be gained by staining slices of brain tissue with a variety of chemicals that bring out areas where specific types of molecules are present in high concentrations. It is also possible to examine the microstructure of brain tissue using a microscope, and to trace the pattern of connections from one brain area to another.[7]

    Cellular structure
    drawing showing a neuron with a fiber emanating from it labeled "axon" and making contact with another cell. An inset shows an enlargement of the contact zone.
    Neurons generate electrical signals that travel along their axons. When a pulse of electricity reaches a junction called a synapse, it causes a neurotransmitter chemical to be released, which binds to receptors on other cells and thereby alters their electrical activity.
    The brains of all species are composed primarily of two broad classes of cells: neurons and glial cells. Glial cells (also known as glia or neuroglia) come in several types, and perform a number of critical functions, including structural support, metabolic support, insulation, and guidance of development. Neurons, however, are usually considered the most important cells in the brain.[8] The property that makes neurons unique is their ability to send signals to specific target cells over long distances.[8] They send these signals by means of an axon, which is a thin protoplasmic fiber that extends from the cell body and projects, usually with numerous branches, to other areas, sometimes nearby, sometimes in distant parts of the brain or body. The length of an axon can be extraordinary: for example, if a pyramidal cell (an excitatory neuron) of the cerebral cortex were magnified so that its cell body became the size of a human body, its axon, equally magnified, would become a cable a few centimeters in diameter, extending more than a kilometer.[9] These axons transmit signals in the form of electrochemical pulses called action potentials, which last less than a thousandth of a second and travel along the axon at speeds of 1–100 meters per second. Some neurons emit action potentials constantly, at rates of 10–100 per second, usually in irregular patterns; other neurons are quiet most of the time, but occasionally emit a burst of action potentials.[10]

    Axons transmit signals to other neurons by means of specialized junctions called synapses. A single axon may make as many as several thousand synaptic connections with other cells.[8] When an action potential, traveling along an axon, arrives at a synapse, it causes a chemical called a neurotransmitter to be released. The neurotransmitter binds to receptor molecules in the membrane of the target cell.[8]

    A bright green cell is seen against a red and black background, with long, highly branched, green processes extending out from it in multiple directions.
    Neurons often have extensive networks of dendrites, which receive synaptic connections. Shown is a pyramidal neuron from the hippocampus, stained for green fluorescent protein.
    Synapses are the key functional elements of the brain.[11] The essential function of the brain is cell-to-cell communication, and synapses are the points at which communication occurs. The human brain has been estimated to contain approximately 100 trillion synapses;[12] even the brain of a fruit fly contains several million.[13] The functions of these synapses are very diverse: some are excitatory (exciting the target cell); others are inhibitory; others work by activating second messenger systems that change the internal chemistry of their target cells in complex ways.[11] A large number of synapses are dynamically modifiable; that is, they are capable of changing strength in a way that is controlled by the patterns of signals that pass through them. It is widely believed that activity-dependent modification of synapses is the brain's primary mechanism for learning and memory.[11]

    Most of the space in the brain is taken up by axons, which are often bundled together in what are called nerve fiber tracts. A myelinated axon is wrapped in a fatty insulating sheath of myelin, which serves to greatly increase the speed of signal propagation. (There are also unmyelinated axons). Myelin is white, making parts of the brain filled exclusively with nerve fibers appear as light-colored white matter, in contrast to the darker-colored grey matter that marks areas with high densities of neuron cell bodies.[8]

    Evolution
    Main article: Evolution of the brain
    Generic bilaterian nervous system
    A rod-shaped body contains a digestive system running from the mouth at one end to the anus at the other. Alongside the digestive system is a nerve cord with a brain at the end, near to the mouth.
    Nervous system of a generic bilaterian animal, in the form of a nerve cord with segmental enlargements, and a "brain" at the front.
    Except for a few primitive organisms such as sponges (which have no nervous system)[14] and cnidarians (which have a nervous system consisting of a diffuse nerve net[14]), all living multicellular animals are bilaterians, meaning animals with a bilaterally symmetric body shape (that is, left and right sides that are approximate mirror images of each other).[15] All bilaterians are thought to have descended from a common ancestor that appeared early in the Cambrian period, 485-540 million years ago, and it has been hypothesized that this common ancestor had the shape of a simple tubeworm with a segmented body.[15] At a schematic level, that basic worm-shape continues to be reflected in the body and nervous system architecture of all modern bilaterians, including vertebrates.[16] The fundamental bilateral body form is a tube with a hollow gut cavity running from the mouth to the anus, and a nerve cord with an enlargement (a ganglion) for each body segment, with an especially large ganglion at the front, called the brain. The brain is small and simple in some species, such as nematode worms; in other species, including vertebrates, it is the most complex organ in the body.[4] Some types of worms, such as leeches, also have an enlarged ganglion at the back end of the nerve cord, known as a "tail brain".[17]

    There are a few types of existing bilaterians that lack a recognizable brain, including echinoderms and tunicates. It has not been definitively established whether the existence of these brainless species indicates that the earliest bilaterians lacked a brain, or whether their ancestors evolved in a way that led to the disappearance of a previously existing brain structure.

    Invertebrates
    A fly resting on a reflective surface. A large, red eye faces the camera. The body appears transparent, apart from black pigment at the end of its abdomen.
    Fruit flies (Drosophila) have been extensively studied to gain insight into the role of genes in brain development.
    This category includes tardigrades, arthropods, molluscs, and numerous types of worms. The diversity of invertebrate body plans is matched by an equal diversity in brain structures.[18]

    Two groups of invertebrates have notably complex brains: arthropods (insects, crustaceans, arachnids, and others), and cephalopods (octopuses, squids, and similar molluscs).[19] The brains of arthropods and cephalopods arise from twin parallel nerve cords that extend through the body of the animal. Arthropods have a central brain, the supraesophageal ganglion, with three divisions and large optical lobes behind each eye for visual processing.[19] Cephalopods such as the octopus and squid have the largest brains of any invertebrates.[20]

    There are several invertebrate species whose brains have been studied intensively because they have properties that make them convenient for experimental work:

    Fruit flies (Drosophila), because of the large array of techniques available for studying their genetics, have been a natural subject for studying the role of genes in brain development.[21] In spite of the large evolutionary distance between insects and mammals, many aspects of Drosophila neurogenetics have been shown to be relevant to humans. The first biological clock genes, for example, were identified by examining Drosophila mutants that showed disrupted daily activity cycles.[22] A search in the genomes of vertebrates revealed a set of analogous genes, which were found to play similar roles in the mouse biological clock—and therefore almost certainly in the human biological clock as well.[23] Studies done on Drosophila, also show that most neuropil regions of the brain are continuously reorganized throughout life in response to specific living conditions.[24]
    The nematode worm Caenorhabditis elegans, like Drosophila, has been studied largely because of its importance in genetics.[25] In the early 1970s, Sydney Brenner chose it as a model organism for studying the way that genes control development. One of the advantages of working with this worm is that the body plan is very stereotyped: the nervous system of the hermaphrodite contains exactly 302 neurons, always in the same places, making identical synaptic connections in every worm.[26] Brenner's team sliced worms into thousands of ultrathin sections and photographed each one under an electron microscope, then visually matched fibers from section to section, to map out every neuron and synapse in the entire body.[27] The complete neuronal wiring diagram of C.elegans – its connectome was achieved.[28] Nothing approaching this level of detail is available for any other organism, and the information gained has enabled a multitude of studies that would otherwise have not been possible.[29]
    The sea slug Aplysia californica was chosen by Nobel Prize-winning neurophysiologist Eric Kandel as a model for studying the cellular basis of learning and memory, because of the simplicity and accessibility of its nervous system, and it has been examined in hundreds of experiments.[30]
    Vertebrates
    A T-shaped object is made up of the cord at the bottom which feeds into a lower central mass. This is topped by a larger central mass with an arm extending from either side.
    The brain of a shark.
    The first vertebrates appeared over 500 million years ago (Mya), during the Cambrian period, and may have resembled the modern hagfish in form.[31] Sharks appeared about 450 Mya, amphibians about 400 Mya, reptiles about 350 Mya, and mammals about 200 Mya. Each species has an equally long evolutionary history, but the brains of modern hagfishes, lampreys, sharks, amphibians, reptiles, and mammals show a gradient of size and complexity that roughly follows the evolutionary sequence. All of these brains contain the same set of basic anatomical components, but many are rudimentary in the hagfish, whereas in mammals the foremost part (the telencephalon) is greatly elaborated and expanded.[32]

    Brains are most simply compared in terms of their size. The relationship between brain size, body size and other variables has been studied across a wide range of vertebrate species. As a rule, brain size increases with body size, but not in a simple linear proportion. In general, smaller animals tend to have larger brains, measured as a fraction of body size. For mammals, the relationship between brain volume and body mass essentially follows a power law with an exponent of about 0.75.[33] This formula describes the central tendency, but every family of mammals departs from it to some degree, in a way that reflects in part the complexity of their behavior. For example, primates have brains 5 to 10 times larger than the formula predicts. Predators tend to have larger brains than their prey, relative to body size.[34]

    The nervous system is shown as a rod with protrusions along its length. The spinal cord at the bottom connects to the hindbrain which widens out before narrowing again. This is connected to the midbrain, which again bulges, and which finally connects to the forebrain which has two large protrusions.
    The main subdivisions of the embryonic vertebrate brain (left), which later differentiate into structures of the adult brain (right).
    All vertebrate brains share a common underlying form, which appears most clearly during early stages of embryonic development. In its earliest form, the brain appears as three swellings at the front end of the neural tube; these swellings eventually become the forebrain, midbrain, and hindbrain (the prosencephalon, mesencephalon, and rhombencephalon, respectively). At the earliest stages of brain development, the three areas are roughly equal in size. In many classes of vertebrates, such as fish and amphibians, the three parts remain similar in size in the adult, but in mammals the forebrain becomes much larger than the other parts, and the midbrain becomes very small.[8]

    The brains of vertebrates are made of very soft tissue.[8] Living brain tissue is pinkish on the outside and mostly white on the inside, with subtle variations in color. Vertebrate brains are surrounded by a system of connective tissue membranes called meninges that separate the skull from the brain. Blood vessels enter the central nervous system through holes in the meningeal layers. The cells in the blood vessel walls are joined tightly to one another, forming the blood–brain barrier, which blocks the passage of many toxins and pathogens[35] (though at the same time blocking antibodies and some drugs, thereby presenting special challenges in treatment of diseases of the brain).[36]

    Neuroanatomists usually divide the vertebrate brain into six main regions: the telencephalon (cerebral hemispheres), diencephalon (thalamus and hypothalamus), mesencephalon (midbrain), cerebellum, pons, and medulla oblongata. Each of these areas has a complex internal structure. Some parts, such as the cerebral cortex and the cerebellar cortex, consist of layers that are folded or convoluted to fit within the available space. Other parts, such as the thalamus and hypothalamus, consist of clusters of many small nuclei. Thousands of distinguishable areas can be identified within the vertebrate brain based on fine distinctions of neural structure, chemistry, and connectivity.[8]

    Although the same basic components are present in all vertebrate brains, some branches of vertebrate evolution have led to substantial distortions of brain geometry, especially in the forebrain area. The brain of a shark shows the basic components in a straightforward way, but in teleost fishes (the great majority of existing fish species), the forebrain has become "everted", like a sock turned inside out. In birds, there are also major changes in forebrain structure.[37] These distortions can make it difficult to match brain components from one species with those of another species.[38]

    Corresponding regions of human and shark brain are shown. The shark brain is splayed out, while the human brain is more compact. The shark brain starts with the medulla, which is surrounded by various structures, and ends with the telencephalon. The cross-section of the human brain shows the medulla at the bottom surrounded by the same structures, with the telencephalon thickly coating the top of the brain.
    The main anatomical regions of the vertebrate brain, shown for shark and human. The same parts are present, but they differ greatly in size and shape.
    Here is a list of some of the most important vertebrate brain components, along with a brief description of their functions as currently understood:

    See also: List of regions in the human brain
    The medulla, along with the spinal cord, contains many small nuclei involved in a wide variety of sensory and involuntary motor functions such as vomiting, heart rate and digestive processes.[8]
    The pons lies in the brainstem directly above the medulla. Among other things, it contains nuclei that control often voluntary but simple acts such as sleep, respiration, swallowing, bladder function, equilibrium, eye movement, facial expressions, and posture.[39]
    The hypothalamus is a small region at the base of the forebrain, whose complexity and importance belies its size. It is composed of numerous small nuclei, each with distinct connections and neurochemistry. The hypothalamus is engaged in additional involuntary or partially voluntary acts such as sleep and wake cycles, eating and drinking, and the release of some hormones.[40]
    The thalamus is a collection of nuclei with diverse functions: some are involved in relaying information to and from the cerebral hemispheres, while others are involved in motivation. The subthalamic area (zona incerta) seems to contain action-generating systems for several types of "consummatory" behaviors such as eating, drinking, defecation, and copulation.[41]
    The cerebellum modulates the outputs of other brain systems, whether motor related or thought related, to make them certain and precise. Removal of the cerebellum does not prevent an animal from doing anything in particular, but it makes actions hesitant and clumsy. This precision is not built-in, but learned by trial and error. The muscle coordination learned while riding a bicycle is an example of a type of neural plasticity that may take place largely within the cerebellum.[8] 10% of the brain's total volume consists of the cerebellum and 50% of all neurons are held within its structure.[42]
    The optic tectum allows actions to be directed toward points in space, most commonly in response to visual input. In mammals it is usually referred to as the superior colliculus, and its best-studied function is to direct eye movements. It also directs reaching movements and other object-directed actions. It receives strong visual inputs, but also inputs from other senses that are useful in directing actions, such as auditory input in owls and input from the thermosensitive pit organs in snakes. In some primitive fishes, such as lampreys, this region is the largest part of the brain.[43] The superior colliculus is part of the midbrain.
    The pallium is a layer of gray matter that lies on the surface of the forebrain and is the most complex and most recent evolutionary development of the brain as an organ.[44] In reptiles and mammals, it is called the cerebral cortex. Multiple functions involve the pallium, including smell and spatial memory. In mammals, where it becomes so large as to dominate the brain, it takes over functions from many other brain areas. In many mammals, the cerebral cortex consists of folded bulges called gyri that create deep furrows or fissures called sulci. The folds increase the surface area of the cortex and therefore increase the amount of gray matter and the amount of information that can be stored and processed.[45]
    The hippocampus, strictly speaking, is found only in mammals. However, the area it derives from, the medial pallium, has counterparts in all vertebrates. There is evidence that this part of the brain is involved in complex events such as spatial memory and navigation in fishes, birds, reptiles, and mammals.[46]
    The basal ganglia are a group of interconnected structures in the forebrain. The primary function of the basal ganglia appears to be action selection: they send inhibitory signals to all parts of the brain that can generate motor behaviors, and in the right circumstances can release the inhibition, so that the action-generating systems are able to execute their actions. Reward and punishment exert their most important neural effects by altering connections within the basal ganglia.[47]
    The olfactory bulb is a special structure that processes olfactory sensory signals and sends its output to the olfactory part of the pallium. It is a major brain component in many vertebrates, but is greatly reduced in humans and other primates (whose senses are dominated by information acquired by sight rather than smell).[48]
    Mammals
    The most obvious difference between the brains of mammals and other vertebrates is in terms of size. On average, a mammal has a brain roughly twice as large as that of a bird of the same body size, and ten times as large as that of a reptile of the same body size.[49]

    Size, however, is not the only difference: there are also substantial differences in shape. The hindbrain and midbrain of mammals are generally similar to those of other vertebrates, but dramatic differences appear in the forebrain, which is greatly enlarged and also altered in structure.[50] The cerebral cortex is the part of the brain that most strongly distinguishes mammals. In non-mammalian vertebrates, the surface of the cerebrum is lined with a comparatively simple three-layered structure called the pallium. In mammals, the pallium evolves into a complex six-layered structure called neocortex or isocortex.[51] Several areas at the edge of the neocortex, including the hippocampus and amygdala, are also much more extensively developed in mammals than in other vertebrates.[50]

    The elaboration of the cerebral cortex carries with it changes to other brain areas. The superior colliculus, which plays a major role in visual control of behavior in most vertebrates, shrinks to a small size in mammals, and many of its functions are taken over by visual areas of the cerebral cortex.[49] The cerebellum of mammals contains a large portion (the neocerebellum) dedicated to supporting the cerebral cortex, which has no counterpart in other vertebrates.[52]

    Primates
    Encephalization Quotient
    Species EQ[53]
    Human 7.4–7.8
    Common chimpanzee 2.2–2.5
    Rhesus monkey 2.1
    Bottlenose dolphin 4.14[54]
    Elephant 1.13–2.36[55]
    Dog 1.2
    Horse 0.9
    Rat 0.4
    See also: Human brain
    The brains of humans and other primates contain the same structures as the brains of other mammals, but are generally larger in proportion to body size.[56] The encephalization quotient (EQ) is used to compare brain sizes across species. It takes into account the nonlinearity of the brain-to-body relationship.[53] Humans have an average EQ in the 7-to-8 range, while most other primates have an EQ in the 2-to-3 range. Dolphins have values higher than those of primates other than humans,[54] but nearly all other mammals have EQ values that are substantially lower.

    Most of the enlargement of the primate brain comes from a massive expansion of the cerebral cortex, especially the prefrontal cortex and the parts of the cortex involved in vision.[57] The visual processing network of primates includes at least 30 distinguishable brain areas, with a complex web of interconnections. It has been estimated that visual processing areas occupy more than half of the total surface of the primate neocortex.[58] The prefrontal cortex carries out functions that include planning, working memory, motivation, attention, and executive control. It takes up a much larger proportion of the brain for primates than for other species, and an especially large fraction of the human brain.[59]

    Development
    Main article: Neural development
    Very simple drawing of the front end of a human embryo, showing each vesicle of the developing brain in a different color.
    Brain of a human embryo in the sixth week of development.
    The brain develops in an intricately orchestrated sequence of stages.[60] It changes in shape from a simple swelling at the front of the nerve cord in the earliest embryonic stages, to a complex array of areas and connections. Neurons are created in special zones that contain stem cells, and then migrate through the tissue to reach their ultimate locations. Once neurons have positioned themselves, their axons sprout and navigate through the brain, branching and extending as they go, until the tips reach their targets and form synaptic connections. In a number of parts of the nervous system, neurons and synapses are produced in excessive numbers during the early stages, and then the unneeded ones are pruned away.[60]

    For vertebrates, the early stages of neural development are similar across all species.[60] As the embryo transforms from a round blob of cells into a wormlike structure, a narrow strip of ectoderm running along the midline of the back is induced to become the neural plate, the precursor of the nervous system. The neural plate folds inward to form the neural groove, and then the lips that line the groove merge to enclose the neural tube, a hollow cord of cells with a fluid-filled ventricle at the center. At the front end, the ventricles and cord swell to form three vesicles that are the precursors of the prosencephalon (forebrain), mesencephalon (midbrain), and rhombencephalon (hindbrain). At the next stage, the forebrain splits into two vesicles called the telencephalon (which will contain the cerebral cortex, basal ganglia, and related structures) and the diencephalon (which will contain the thalamus and hypothalamus). At about the same time, the hindbrain splits into the metencephalon (which will contain the cerebellum and pons) and the myelencephalon (which will contain the medulla oblongata). Each of these areas contains proliferative zones where neurons and glial cells are generated; the resulting cells then migrate, sometimes for long distances, to their final positions.[60]

    Once a neuron is in place, it extends dendrites and an axon into the area around it. Axons, because they commonly extend a great distance from the cell body and need to reach specific targets, grow in a particularly complex way. The tip of a growing axon consists of a blob of protoplasm called a growth cone, studded with chemical receptors. These receptors sense the local environment, causing the growth cone to be attracted or repelled by various cellular elements, and thus to be pulled in a particular direction at each point along its path. The result of this pathfinding process is that the growth cone navigates through the brain until it reaches its destination area, where other chemical cues cause it to begin generating synapses. Considering the entire brain, thousands of genes create products that influence axonal pathfinding.[60]

    The synaptic network that finally emerges is only partly determined by genes, though. In many parts of the brain, axons initially "overgrow", and then are "pruned" by mechanisms that depend on neural activity.[60] In the projection from the eye to the midbrain, for example, the structure in the adult contains a very precise mapping, connecting each point on the surface of the retina to a corresponding point in a midbrain layer. In the first stages of development, each axon from the retina is guided to the right general vicinity in the midbrain by chemical cues, but then branches very profusely and makes initial contact with a wide swath of midbrain neurons. The retina, before birth, contains special mechanisms that cause it to generate waves of activity that originate spontaneously at a random point and then propagate slowly across the retinal layer. These waves are useful because they cause neighboring neurons to be active at the same time; that is, they produce a neural activity pattern that contains information about the spatial arrangement of the neurons. This information is exploited in the midbrain by a mechanism that causes synapses to weaken, and eventually vanish, if activity in an axon is not followed by activity of the target cell. The result of this sophisticated process is a gradual tuning and tightening of the map, leaving it finally in its precise adult form.[61]

    Similar things happen in other brain areas: an initial synaptic matrix is generated as a result of genetically determined chemical guidance, but then gradually refined by activity-dependent mechanisms, partly driven by internal dynamics, partly by external sensory inputs. In some cases, as with the retina-midbrain system, activity patterns depend on mechanisms that operate only in the developing brain, and apparently exist solely to guide development.[61]

    In humans and many other mammals, new neurons are created mainly before birth, and the infant brain contains substantially more neurons than the adult brain.[60] There are, however, a few areas where new neurons continue to be generated throughout life. The two areas for which adult neurogenesis is well established are the olfactory bulb, which is involved in the sense of smell, and the dentate gyrus of the hippocampus, where there is evidence that the new neurons play a role in storing newly acquired memories. With these exceptions, however, the set of neurons that is present in early childhood is the set that is present for life. Glial cells are different: as with most types of cells in the body, they are generated throughout the lifespan.[62]

    There has long been debate about whether the qualities of mind, personality, and intelligence can be attributed to heredity or to upbringing—this is the nature and nurture controversy.[63] Although many details remain to be settled, neuroscience research has clearly shown that both factors are important. Genes determine the general form of the brain, and genes determine how the brain reacts to experience. Experience, however, is required to refine the matrix of synaptic connections, which in its developed form contains far more information than the genome does. In some respects, all that matters is the presence or absence of experience during critical periods of development.[64] In other respects, the quantity and quality of experience are important; for example, there is substantial evidence that animals raised in enriched environments have thicker cerebral cortices, indicating a higher density of synaptic connections, than animals whose levels of stimulation are restricted.[65]

    Physiology
    The functions of the brain depend on the ability of neurons to transmit electrochemical signals to other cells, and their ability to respond appropriately to electrochemical signals received from other cells. The electrical properties of neurons are controlled by a wide variety of biochemical and metabolic processes, most notably the interactions between neurotransmitters and receptors that take place at synapses.[8]

    Neurotransmitters and receptors
    Neurotransmitters are chemicals that are released at synapses when an action potential activates them—neurotransmitters attach themselves to receptor molecules on the membrane of the synapse's target cell, and thereby alter the electrical or chemical properties of the receptor molecules. With few exceptions, each neuron in the brain releases the same chemical neurotransmitter, or combination of neurotransmitters, at all the synaptic connections it makes with other neurons; this rule is known as Dale's principle.[8] Thus, a neuron can be characterized by the neurotransmitters that it releases. The great majority of psychoactive drugs exert their effects by altering specific neurotransmitter systems. This applies to drugs such as cannabinoids, nicotine, heroin, cocaine, alcohol, fluoxetine, chlorpromazine, and many others.[66]

    The two neurotransmitters that are used most widely in the vertebrate brain are glutamate, which almost always exerts excitatory effects on target neurons, and gamma-aminobutyric acid (GABA), which is almost always inhibitory. Neurons using these transmitters can be found in nearly every part of the brain.[67] Because of their ubiquity, drugs that act on glutamate or GABA tend to have broad and powerful effects. Some general anesthetics act by reducing the effects of glutamate; most tranquilizers exert their sedative effects by enhancing the effects of GABA.[68]

    There are dozens of other chemical neurotransmitters that are used in more limited areas of the brain, often areas dedicated to a particular function. Serotonin, for example—the primary target of antidepressant drugs and many dietary aids—comes exclusively from a small brainstem area called the raphe nuclei.[69] Norepinephrine, which is involved in arousal, comes exclusively from a nearby small area called the locus coeruleus.[70] Other neurotransmitters such as acetylcholine and dopamine have multiple sources in the brain, but are not as ubiquitously distributed as glutamate and GABA.[71]

    Electrical activity
    Graph showing 16 voltage traces going across the page from left to right, each showing a different signal. At the middle of the page all of the traces abruptly begin to show sharp jerky spikes, which continue to the end of the plot.
    Brain electrical activity recorded from a human patient during an epileptic seizure.
    As a side effect of the electrochemical processes used by neurons for signaling, brain tissue generates electric fields when it is active. When large numbers of neurons show synchronized activity, the electric fields that they generate can be large enough to detect outside the skull, using electroencephalography (EEG)[72] or magnetoencephalography (MEG). EEG recordings, along with recordings made from electrodes implanted inside the brains of animals such as rats, show that the brain of a living animal is constantly active, even during sleep.[73] Each part of the brain shows a mixture of rhythmic and nonrhythmic activity, which may vary according to behavioral state. In mammals, the cerebral cortex tends to show large slow delta waves during sleep, faster alpha waves when the animal is awake but inattentive, and chaotic-looking irregular activity when the animal is actively engaged in a task. During an epileptic seizure, the brain's inhibitory control mechanisms fail to function and electrical activity rises to pathological levels, producing EEG traces that show large wave and spike patterns not seen in a healthy brain. Relating these population-level patterns to the computational functions of individual neurons is a major focus of current research in neurophysiology.[73]

    Metabolism
    All vertebrates have a blood–brain barrier that allows metabolism inside the brain to operate differently from metabolism in other parts of the body. Glial cells play a major role in brain metabolism by controlling the chemical composition of the fluid that surrounds neurons, including levels of ions and nutrients.[74]

    Brain tissue consumes a large amount of energy in proportion to its volume, so large brains place severe metabolic demands on animals. The need to limit body weight in order, for example, to fly, has apparently led to selection for a reduction of brain size in some species, such as bats.[75] Most of the brain's energy consumption goes into sustaining the electric charge (membrane potential) of neurons.[74] Most vertebrate species devote between 2% and 8% of basal metabolism to the brain. In primates, however, the percentage is much higher—in humans it rises to 20–25%.[76] The energy consumption of the brain does not vary greatly over time, but active regions of the cerebral cortex consume somewhat more energy than inactive regions; this forms the basis for the functional brain imaging methods of PET, fMRI,[77] and NIRS.[78] The brain typically gets most of its energy from oxygen-dependent metabolism of glucose (i.e., blood sugar),[74] but ketones provide a major alternative source, together with contributions from medium chain fatty acids (caprylic and heptanoic acids),[79][80] lactate,[81] acetate,[82] and possibly amino acids.[83]

    Function

    Model of a neural circuit in the cerebellum, as proposed by James S. Albus.
    Information from the sense organs is collected in the brain. There it is used to determine what actions the organism is to take. The brain processes the raw data to extract information about the structure of the environment. Next it combines the processed information with information about the current needs of the animal and with memory of past circumstances. Finally, on the basis of the results, it generates motor response patterns. These signal-processing tasks require intricate interplay between a variety of functional subsystems.[84]

    The function of the brain is to provide coherent control over the actions of an animal. A centralized brain allows groups of muscles to be co-activated in complex patterns; it also allows stimuli impinging on one part of the body to evoke responses in other parts, and it can prevent different parts of the body from acting at cross-purposes to each other.[84]

    Perception
    Drawing showing the ear, inner ear, and brain areas involved in hearing. A series of light blue arrows shows the flow of signals through the system.
    Diagram of signal processing in the auditory system.
    The human brain is provided with information about light, sound, the chemical composition of the atmosphere, temperature, head orientation, limb position, the chemical composition of the bloodstream, and more. In other animals additional senses are present, such as the infrared heat-sense of snakes, the magnetic field sense of some birds, or the electric field sense of some types of fish.

    Each sensory system begins with specialized receptor cells,[8] such as light-receptive neurons in the retina of the eye, or vibration-sensitive neurons in the cochlea of the ear. The axons of sensory receptor cells travel into the spinal cord or brain, where they transmit their signals to a first-order sensory nucleus dedicated to one specific sensory modality. This primary sensory nucleus sends information to higher-order sensory areas that are dedicated to the same modality. Eventually, via a way-station in the thalamus, the signals are sent to the cerebral cortex, where they are processed to extract the relevant features, and integrated with signals coming from other sensory systems.[8]

    Motor control
    Motor systems are areas of the brain that are involved in initiating body movements, that is, in activating muscles. Except for the muscles that control the eye, which are driven by nuclei in the midbrain, all the voluntary muscles in the body are directly innervated by motor neurons in the spinal cord and hindbrain.[8] Spinal motor neurons are controlled both by neural circuits intrinsic to the spinal cord, and by inputs that descend from the brain. The intrinsic spinal circuits implement many reflex responses, and contain pattern generators for rhythmic movements such as walking or swimming. The descending connections from the brain allow for more sophisticated control.[8]

    The brain contains several motor areas that project directly to the spinal cord. At the lowest level are motor areas in the medulla and pons, which control stereotyped movements such as walking, breathing, or swallowing. At a higher level are areas in the midbrain, such as the red nucleus, which is responsible for coordinating movements of the arms and legs. At a higher level yet is the primary motor cortex, a strip of tissue located at the posterior edge of the frontal lobe. The primary motor cortex sends projections to the subcortical motor areas, but also sends a massive projection directly to the spinal cord, through the pyramidal tract. This direct corticospinal projection allows for precise voluntary control of the fine details of movements. Other motor-related brain areas exert secondary effects by projecting to the primary motor areas. Among the most important secondary areas are the premotor cortex, basal ganglia, and cerebellum.[8]

    Major areas involved in controlling movement
    Area Location Function
    Ventral horn Spinal cord Contains motor neurons that directly activate muscles[85]
    Oculomotor nuclei Midbrain Contains motor neurons that directly activate the eye muscles[86]
    Cerebellum Hindbrain Calibrates precision and timing of movements[8]
    Basal ganglia Forebrain Action selection on the basis of motivation[87]
    Motor cortex Frontal lobe Direct cortical activation of spinal motor circuits
    Premotor cortex Frontal lobe Groups elementary movements into coordinated patterns[8]
    Supplementary motor area Frontal lobe Sequences movements into temporal patterns[88]
    Prefrontal cortex Frontal lobe Planning and other executive functions[89]
    In addition to all of the above, the brain and spinal cord contain extensive circuitry to control the autonomic nervous system, which works by secreting hormones and by modulating the "smooth" muscles of the gut.[8]

    Arousal
    See also: Sleep
    Many animals alternate between sleeping and waking in a daily cycle. Arousal and alertness are also modulated on a finer time scale by a network of brain areas.[8]

    A key component of the arousal system is the suprachiasmatic nucleus (SCN), a tiny part of the hypothalamus located directly above the point at which the optic nerves from the two eyes cross. The SCN contains the body's central biological clock. Neurons there show activity levels that rise and fall with a period of about 24 hours, circadian rhythms: these activity fluctuations are driven by rhythmic changes in expression of a set of "clock genes". The SCN continues to keep time even if it is excised from the brain and placed in a dish of warm nutrient solution, but it ordinarily receives input from the optic nerves, through the retinohypothalamic tract (RHT), that allows daily light-dark cycles to calibrate the clock.[90]

    The SCN projects to a set of areas in the hypothalamus, brainstem, and midbrain that are involved in implementing sleep-wake cycles. An important component of the system is the reticular formation, a group of neuron-clusters scattered diffusely through the core of the lower brain. Reticular neurons send signals to the thalamus, which in turn sends activity-level-controlling signals to every part of the cortex. Damage to the reticular formation can produce a permanent state of coma.[8]

    Sleep involves great changes in brain activity.[8] Until the 1950s it was generally believed that the brain essentially shuts off during sleep,[91] but this is now known to be far from true; activity continues, but patterns become very different. There are two types of sleep: REM sleep (with dreaming) and NREM (non-REM, usually without dreaming) sleep, which repeat in slightly varying patterns throughout a sleep episode. Three broad types of distinct brain activity patterns can be measured: REM, light NREM and deep NREM. During deep NREM sleep, also called slow wave sleep, activity in the cortex takes the form of large synchronized waves, whereas in the waking state it is noisy and desynchronized. Levels of the neurotransmitters norepinephrine and serotonin drop during slow wave sleep, and fall almost to zero during REM sleep; levels of acetylcholine show the reverse pattern.[8]

    Homeostasis

    Cross-section of a human head, showing location of the hypothalamus.
    For any animal, survival requires maintaining a variety of parameters of bodily state within a limited range of variation: these include temperature, water content, salt concentration in the bloodstream, blood glucose levels, blood oxygen level, and others.[92] The ability of an animal to regulate the internal environment of its body—the milieu intérieur, as pioneering physiologist Claude Bernard called it—is known as homeostasis (Greek for "standing still").[93] Maintaining homeostasis is a crucial function of the brain. The basic principle that underlies homeostasis is negative feedback: any time a parameter diverges from its set-point, sensors generate an error signal that evokes a response that causes the parameter to shift back toward its optimum value.[92] (This principle is widely used in engineering, for example in the control of temperature using a thermostat.)

    In vertebrates, the part of the brain that plays the greatest role is the hypothalamus, a small region at the base of the forebrain whose size does not reflect its complexity or the importance of its function.[92] The hypothalamus is a collection of small nuclei, most of which are involved in basic biological functions. Some of these functions relate to arousal or to social interactions such as sexuality, aggression, or maternal behaviors; but many of them relate to homeostasis. Several hypothalamic nuclei receive input from sensors located in the lining of blood vessels, conveying information about temperature, sodium level, glucose level, blood oxygen level, and other parameters. These hypothalamic nuclei send output signals to motor areas that can generate actions to rectify deficiencies. Some of the outputs also go to the pituitary gland, a tiny gland attached to the brain directly underneath the hypothalamus. The pituitary gland secretes hormones into the bloodstream, where they circulate throughout the body and induce changes in cellular activity.[94]

    Motivation

    Components of the basal ganglia, shown in two cross-sections of the human brain. Blue: caudate nucleus and putamen. Green: globus pallidus. Red: subthalamic nucleus. Black: substantia nigra.
    The individual animals need to express survival-promoting behaviors, such as seeking food, water, shelter, and a mate.[95] The motivational system in the brain monitors the current state of satisfaction of these goals, and activates behaviors to meet any needs that arise. The motivational system works largely by a reward–punishment mechanism. When a particular behavior is followed by favorable consequences, the reward mechanism in the brain is activated, which induces structural changes inside the brain that cause the same behavior to be repeated later, whenever a similar situation arises. Conversely, when a behavior is followed by unfavorable consequences, the brain's punishment mechanism is activated, inducing structural changes that cause the behavior to be suppressed when similar situations arise in the future.[96]

    Most organisms studied to date utilize a reward–punishment mechanism: for instance, worms and insects can alter their behavior to seek food sources or to avoid dangers.[97] In vertebrates, the reward-punishment system is implemented by a specific set of brain structures, at the heart of which lie the basal ganglia, a set of interconnected areas at the base of the forebrain.[47] The basal ganglia are the central site at which decisions are made: the basal ganglia exert a sustained inhibitory control over most of the motor systems in the brain; when this inhibition is released, a motor system is permitted to execute the action it is programmed to carry out. Rewards and punishments function by altering the relationship between the inputs that the basal ganglia receive and the decision-signals that are emitted. The reward mechanism is better understood than the punishment mechanism, because its role in drug abuse has caused it to be studied very intensively. Research has shown that the neurotransmitter dopamine plays a central role: addictive drugs such as cocaine, amphetamine, and nicotine either cause dopamine levels to rise or cause the effects of dopamine inside the brain to be enhanced.[98]

    Learning and memory
    Almost all animals are capable of modifying their behavior as a result of experience—even the most primitive types of worms. Because behavior is driven by brain activity, changes in behavior must somehow correspond to changes inside the brain. Already in the late 19th century theorists like Santiago Ramón y Cajal argued that the most plausible explanation is that learning and memory are expressed as changes in the synaptic connections between neurons.[99] Until 1970, however, experimental evidence to support the synaptic plasticity hypothesis was lacking. In 1971 Tim Bliss and Terje Lømo published a paper on a phenomenon now called long-term potentiation: the paper showed clear evidence of activity-induced synaptic changes that lasted for at least several days.[100] Since then technical advances have made these sorts of experiments much easier to carry out, and thousands of studies have been made that have clarified the mechanism of synaptic change, and uncovered other types of activity-driven synaptic change in a variety of brain areas, including the cerebral cortex, hippocampus, basal ganglia, and cerebellum.[101] Brain-derived neurotrophic factor (BDNF) and physical activity appear to play a beneficial role in the process.[102]

    Neuroscientists currently distinguish several types of learning and memory that are implemented by the brain in distinct ways:

    Working memory is the ability of the brain to maintain a temporary representation of information about the task that an animal is currently engaged in. This sort of dynamic memory is thought to be mediated by the formation of cell assemblies—groups of activated neurons that maintain their activity by constantly stimulating one another.[103]
    Episodic memory is the ability to remember the details of specific events. This sort of memory can last for a lifetime. Much evidence implicates the hippocampus in playing a crucial role: people with severe damage to the hippocampus sometimes show amnesia, that is, inability to form new long-lasting episodic memories.[104]
    Semantic memory is the ability to learn facts and relationships. This sort of memory is probably stored largely in the cerebral cortex, mediated by changes in connections between cells that represent specific types of information.[105]
    Instrumental learning is the ability for rewards and punishments to modify behavior. It is implemented by a network of brain areas centered on the basal ganglia.[106]
    Motor learning is the ability to refine patterns of body movement by practicing, or more generally by repetition. A number of brain areas are involved, including the premotor cortex, basal ganglia, and especially the cerebellum, which functions as a large memory bank for microadjustments of the parameters of movement.[107]
    Research
    Main article: Neuroscience
    "Brain research" redirects here. For the scientific journal, see Brain Research.

    The Human Brain Project is a large scientific research project, starting in 2013, which aims to simulate the complete human brain.
    The field of neuroscience encompasses all approaches that seek to understand the brain and the rest of the nervous system.[8] Psychology seeks to understand mind and behavior, and neurology is the medical discipline that diagnoses and treats diseases of the nervous system. The brain is also the most important organ studied in psychiatry, the branch of medicine that works to study, prevent, and treat mental disorders.[108] Cognitive science seeks to unify neuroscience and psychology with other fields that concern themselves with the brain, such as computer science (artificial intelligence and similar fields) and philosophy.[109]

    The oldest method of studying the brain is anatomical, and until the middle of the 20th century, much of the progress in neuroscience came from the development of better cell stains and better microscopes. Neuroanatomists study the large-scale structure of the brain as well as the microscopic structure of neurons and their components, especially synapses. Among other tools, they employ a plethora of stains that reveal neural structure, chemistry, and connectivity. In recent years, the development of immunostaining techniques has allowed investigation of neurons that express specific sets of genes. Also, functional neuroanatomy uses medical imaging techniques to correlate variations in human brain structure with differences in cognition or behavior.[110]

    Neurophysiologists study the chemical, pharmacological, and electrical properties of the brain: their primary tools are drugs and recording devices. Thousands of experimentally developed drugs affect the nervous system, some in highly specific ways. Recordings of brain activity can be made using electrodes, either glued to the scalp as in EEG studies, or implanted inside the brains of animals for extracellular recordings, which can detect action potentials generated by individual neurons.[111] Because the brain does not contain pain receptors, it is possible using these techniques to record brain activity from animals that are awake and behaving without causing distress. The same techniques have occasionally been used to study brain activity in human patients suffering from intractable epilepsy, in cases where there was a medical necessity to implant electrodes to localize the brain area responsible for epileptic seizures.[112] Functional imaging techniques such as functional magnetic resonance imaging are also used to study brain activity; these techniques have mainly been used with human subjects, because they require a conscious subject to remain motionless for long periods of time, but they have the great advantage of being noninvasive.[113]

    Drawing showing a monkey in a restraint chair, a computer monitor, a rototic arm, and three pieces of computer equipment, with arrows between them to show the flow of information.
    Design of an experiment in which brain activity from a monkey was used to control a robotic arm.[114]
    Another approach to brain function is to examine the consequences of damage to specific brain areas. Even though it is protected by the skull and meninges, surrounded by cerebrospinal fluid, and isolated from the bloodstream by the blood–brain barrier, the delicate nature of the brain makes it vulnerable to numerous diseases and several types of damage. In humans, the effects of strokes and other types of brain damage have been a key source of information about brain function. Because there is no ability to experimentally control the nature of the damage, however, this information is often difficult to interpret. In animal studies, most commonly involving rats, it is possible to use electrodes or locally injected chemicals to produce precise patterns of damage and then examine the consequences for behavior.[115]

    Computational neuroscience encompasses two approaches: first, the use of computers to study the brain; second, the study of how brains perform computation. On one hand, it is possible to write a computer program to simulate the operation of a group of neurons by making use of systems of equations that describe their electrochemical activity; such simulations are known as biologically realistic neural networks. On the other hand, it is possible to study algorithms for neural computation by simulating, or mathematically analyzing, the operations of simplified "units" that have some of the properties of neurons but abstract out much of their biological complexity. The computational functions of the brain are studied both by computer scientists and neuroscientists.[116]

    Computational neurogenetic modeling is concerned with the study and development of dynamic neuronal models for modeling brain functions with respect to genes and dynamic interactions between genes.

    Recent years have seen increasing applications of genetic and genomic techniques to the study of the brain [117] and a focus on the roles of neurotrophic factors and physical activity in neuroplasticity.[102] The most common subjects are mice, because of the availability of technical tools. It is now possible with relative ease to "knock out" or mutate a wide variety of genes, and then examine the effects on brain function. More sophisticated approaches are also being used: for example, using Cre-Lox recombination it is possible to activate or deactivate genes in specific parts of the brain, at specific times.[117]

    History

    Illustration by René Descartes of how the brain implements a reflex response.
    See also: History of neuroscience
    The oldest brain to have been discovered was in Armenia in the Areni-1 cave complex. The brain, estimated to be over 5,000 years old, was found in the skull of a 12 to 14-year-old girl. Although the brains were shriveled, they were well preserved due to the climate found inside the cave.[118]

    Early philosophers were divided as to whether the seat of the soul lies in the brain or heart. Aristotle favored the heart, and thought that the function of the brain was merely to cool the blood. Democritus, the inventor of the atomic theory of matter, argued for a three-part soul, with intellect in the head, emotion in the heart, and lust near the liver.[119] The unknown author of On the Sacred Disease, a medical treatise in the Hippocratic Corpus, came down unequivocally in favor of the brain, writing:

    Men ought to know that from nothing else but the brain come joys, delights, laughter and sports, and sorrows, griefs, despondency, and lamentations. ... And by the same organ we become mad and delirious, and fears and terrors assail us, some by night, and some by day, and dreams and untimely wanderings, and cares that are not suitable, and ignorance of present circumstances, desuetude, and unskillfulness. All these things we endure from the brain, when it is not healthy...

    On the Sacred Disease, attributed to Hippocrates[120]

    Andreas Vesalius' Fabrica, published in 1543, showing the base of the human brain, including optic chiasma, cerebellum, olfactory bulbs, etc.
    The Roman physician Galen also argued for the importance of the brain, and theorized in some depth about how it might work. Galen traced out the anatomical relationships among brain, nerves, and muscles, demonstrating that all muscles in the body are connected to the brain through a branching network of nerves. He postulated that nerves activate muscles mechanically by carrying a mysterious substance he called pneumata psychikon, usually translated as "animal spirits".[119] Galen's ideas were widely known during the Middle Ages, but not much further progress came until the Renaissance, when detailed anatomical study resumed, combined with the theoretical speculations of René Descartes and those who followed him. Descartes, like Galen, thought of the nervous system in hydraulic terms. He believed that the highest cognitive functions are carried out by a non-physical res cogitans, but that the majority of behaviors of humans, and all behaviors of animals, could be explained mechanistically.[121]

    The first real progress toward a modern understanding of nervous function, though, came from the investigations of Luigi Galvani (1737–1798), who discovered that a shock of static electricity applied to an exposed nerve of a dead frog could cause its leg to contract. Since that time, each major advance in understanding has followed more or less directly from the development of a new technique of investigation. Until the early years of the 20th century, the most important advances were derived from new methods for staining cells.[122] Particularly critical was the invention of the Golgi stain, which (when correctly used) stains only a small fraction of neurons, but stains them in their entirety, including cell body, dendrites, and axon. Without such a stain, brain tissue under a microscope appears as an impenetrable tangle of protoplasmic fibers, in which it is impossible to determine any structure. In the hands of Camillo Golgi, and especially of the Spanish neuroanatomist Santiago Ramón y Cajal, the new stain revealed hundreds of distinct types of neurons, each with its own unique dendritic structure and pattern of connectivity.[123]

    A drawing on yellowing paper with an archiving stamp in the corner. A spidery tree branch structure connects to the top of a mass. A few narrow processes follow away from the bottom of the mass.
    Drawing by Santiago Ramón y Cajal of two types of Golgi-stained neurons from the cerebellum of a pigeon.
    In the first half of the 20th century, advances in electronics enabled investigation of the electrical properties of nerve cells, culminating in work by Alan Hodgkin, Andrew Huxley, and others on the biophysics of the action potential, and the work of Bernard Katz and others on the electrochemistry of the synapse.[124] These studies complemented the anatomical picture with a conception of the brain as a dynamic entity. Reflecting the new understanding, in 1942 Charles Sherrington visualized the workings of the brain waking from sleep:

    The great topmost sheet of the mass, that where hardly a light had twinkled or moved, becomes now a sparkling field of rhythmic flashing points with trains of traveling sparks hurrying hither and thither. The brain is waking and with it the mind is returning. It is as if the Milky Way entered upon some cosmic dance. Swiftly the head mass becomes an enchanted loom where millions of flashing shuttles weave a dissolving pattern, always a meaningful pattern though never an abiding one; a shifting harmony of subpatterns.

    —Sherrington, 1942, Man on his Nature[125]
    The invention of electronic computers in the 1940s, along with the development of mathematical information theory, led to a realization that brains can potentially be understood as information processing systems. This concept formed the basis of the field of cybernetics, and eventually gave rise to the field now known as computational neuroscience.[126] The earliest attempts at cybernetics were somewhat crude in that they treated the brain as essentially a digital computer in disguise, as for example in John von Neumann's 1958 book, The Computer and the Brain.[127] Over the years, though, accumulating information about the electrical responses of brain cells recorded from behaving animals has steadily moved theoretical concepts in the direction of increasing realism.[126]

    One of the most influential early contributions was a 1959 paper titled What the frog's eye tells the frog's brain: the paper examined the visual responses of neurons in the retina and optic tectum of frogs, and came to the conclusion that some neurons in the tectum of the frog are wired to combine elementary responses in a way that makes them function as "bug perceivers".[128] A few years later David Hubel and Torsten Wiesel discovered cells in the primary visual cortex of monkeys that become active when sharp edges move across specific points in the field of view—a discovery for which they won a Nobel Prize.[129] Follow-up studies in higher-order visual areas found cells that detect binocular disparity, color, movement, and aspects of shape, with areas located at increasing distances from the primary visual cortex showing increasingly complex responses.[130] Other investigations of brain areas unrelated to vision have revealed cells with a wide variety of response correlates, some related to memory, some to abstract types of cognition such as space.[131]

    Theorists have worked to understand these response patterns by constructing mathematical models of neurons and neural networks, which can be simulated using computers.[126] Some useful models are abstract, focusing on the conceptual structure of neural algorithms rather than the details of how they are implemented in the brain; other models attempt to incorporate data about the biophysical properties of real neurons.[132] No model on any level is yet considered to be a fully valid description of brain function, though. The essential difficulty is that sophisticated computation by neural networks requires distributed processing in which hundreds or thousands of neurons work cooperatively—current methods of brain activity recording are only capable of isolating action potentials from a few dozen neurons at a time.[133]

    Furthermore, even single neurons appear to be complex and capable of performing computations.[134] So, brain models that don't reflect this are too abstract to be representative of brain operation; models that do try to capture this are very computationally expensive and arguably intractable with present computational resources. However, the Human Brain Project is trying to build a realistic, detailed computational model of the entire human brain. The wisdom of this approach has been publicly contested, with high-profile scientists on both sides of the argument.

    In the second half of the 20th century, developments in chemistry, electron microscopy, genetics, computer science, functional brain imaging, and other fields progressively opened new windows into brain structure and function. In the United States, the 1990s were officially designated as the "Decade of the Brain" to commemorate advances made in brain research, and to promote funding for such research.[135]

    In the 21st century, these trends have continued, and several new approaches have come into prominence, including multielectrode recording, which allows the activity of many brain cells to be recorded all at the same time;[136] genetic engineering, which allows molecular components of the brain to be altered experimentally;[117] genomics, which allows variations in brain structure to be correlated with variations in DNA properties[137] and neuroimaging.

    ....

    Near-death experience
    From Wikipedia, the free encyclopedia
    Jump to navigationJump to search
    For other uses, see Near-death experience (disambiguation).
    "NDE" redirects here. For other uses, see NDE (disambiguation).
    "Near death" redirects here. For the comic book, see Near Death (comics).
    A near-death experience (NDE) is a personal experience associated with death or impending death. When positive, such experiences may encompass a variety of sensations including detachment from the body, feelings of levitation, total serenity, security, warmth, the experience of absolute dissolution, and the presence of a light. When negative, such experiences may include sensations of anguish and distress.[1] NDEs are a recognized part of some transcendental and religious beliefs in an afterlife.[1][2][3][4]

    Different models have been described to explain NDEs.[5] Neuroscience research suggests that an NDE is a subjective phenomenon resulting from "disturbed bodily multisensory integration" that occurs during life-threatening events.[6]


    Contents
    1 Etymology
    2 Characteristics
    2.1 Common elements
    2.2 Stages
    2.3 Clinical circumstances
    2.4 After-effects
    3 Historical reports, incidence and prevalence
    4 Research
    4.1 Near-death studies
    4.2 Clinical research in cardiac arrest patients
    4.2.1 Parnia 2001 study
    4.2.2 Van Lommel's study
    4.2.3 Awareness during Resuscitation (AWARE) study
    4.2.4 AWARE II
    4.2.5 Meditation-Induced NDEs
    5 Explanatory models
    5.1 Spiritual or transcendental theories
    5.2 Psychological explanations
    5.2.1 Depersonalization model
    5.2.2 Expectancy model
    5.2.3 Dissociation model
    5.2.4 Birth model
    5.3 Physiological explanations (organic theories)
    5.3.1 Neuroanatomical models
    5.3.2 Neurochemical models
    5.3.3 Multi-factorial models
    5.3.4 Low oxygen levels (and G-LOC) model
    5.3.5 Altered blood gas levels models
    5.3.6 Other models
    6 Cross-cultural aspects
    7 See also
    8 References
    9 External links
    10 Further reading
    Etymology

    Ascent of the Blessed by Hieronymus Bosch is associated by some NDE researchers with aspects of the NDE.[7][8]
    The equivalent French term expérience de mort imminente (experience of imminent death) was proposed by French psychologist and epistemologist Victor Egger as a result of discussions in the 1890s among philosophers and psychologists concerning climbers' stories of the panoramic life review during falls.[9][10] In 1892 a series of subjective observations by workers falling from scaffolds, war soldiers who suffered injuries, climbers who had fallen from heights or other individuals who had come close to death (near drownings, accidents) was reported by Albert Heim. This was also the first time the phenomenon was described as clinical syndrome.[11] In 1968 Celia Green published an analysis of 400 first-hand accounts of out-of-body experiences.[12] This represented the first attempt to provide a taxonomy of such experiences, viewed simply as anomalous perceptual experiences, or hallucinations. In 1969, Swiss-American psychiatrist and pioneer in near-death studies Elisabeth Kubler-Ross published her groundbreaking book On Death and Dying: What the dying have to teach doctors, nurses, clergy, and their own families. These experiences were also popularized by the work of psychiatrist Raymond Moody, who in 1975 coined the term "near-death experience" (NDE) as an umbrella term for the different elements (out of body experiences, the "panoramic life review," the Light, the tunnel, or the border).[11] The term "near-death experience" had already been used by John C. Lilly in 1972.[13]

    Characteristics
    Common elements
    Researchers have identified the common elements that define near-death experiences.[3] Bruce Greyson argues that the general features of the experience include impressions of being outside one's physical body, visions of deceased relatives and religious figures, and transcendence of egotic and spatiotemporal boundaries.[14] Many common elements have been reported, although the person's interpretation of these events often corresponds with the cultural, philosophical, or religious beliefs of the person experiencing it. For example, in the US, where 46% of the population believes in guardian angels, they will often be identified as angels or deceased loved ones (or will be unidentified), while Hindus will often identify them as messengers of the god of death.[15][16]

    Common traits that have been reported by NDErs are as follows:

    A sense/awareness of being dead.[3]
    A sense of peace, well-being and painlessness. Positive emotions. A sense of removal from the world.[3]
    An out-of-body experience. A perception of one's body from an outside position, sometimes observing medical professionals performing resuscitation efforts.[3][17]
    A "tunnel experience" or entering a darkness. A sense of moving up, or through, a passageway or staircase.[3][17]
    A rapid movement toward and/or sudden immersion in a powerful light (or "Being of Light") which communicates with the person.[18]
    An intense feeling of unconditional love and acceptance.[19]
    Encountering "Beings of Light", "Beings dressed in white", or similar. Also, the possibility of being reunited with deceased loved ones.[3][17]
    Receiving a life review, commonly referred to as "seeing one's life flash before one's eyes".[3]
    Approaching a border or a decision by oneself or others to return to one's body, often accompanied by a reluctance to return.[3][17]
    Suddenly finding oneself back inside one's body.[20]
    Connection to the cultural beliefs held by the individual, which seem to dictate some of the phenomena experienced in the NDE and particularly the later interpretation thereof.[15][page needed]
    Stages
    Kenneth Ring (1980) subdivided the NDE on a five-stage continuum. The subdivisions were:[21]

    Peace
    Body separation
    Entering darkness
    Seeing the light
    Entering the light
    Charlotte Martial, a neuropsychologist from the University of Liège and University Hospital of Liège who led a team that investigated 154 NDE cases, concluded that there is not a fixed sequence of events.[22]

    Clinical circumstances
    Kenneth Ring argues that attempted suicides do not lead more often to unpleasant NDEs than unintended near-death situations.[23]

    After-effects
    NDEs are associated with changes in personality and outlook on life.[3] Ring has identified a consistent set of value and belief changes associated with people who have had a near-death experience. Among these changes, he found a greater appreciation for life, higher self-esteem, greater compassion for others, less concern for acquiring material wealth, a heightened sense of purpose and self-understanding, desire to learn, elevated spirituality, greater ecological sensitivity and planetary concern, and a feeling of being more intuitive.[3] However, not all after-effects are beneficial[24] and Greyson describes circumstances where changes in attitudes and behavior can lead to psychosocial and psychospiritual problems.[25]

    Historical reports, incidence and prevalence
    NDEs have been recorded since ancient times.[26] The oldest known medical report of near-death experiences was written by Pierre-Jean du Monchaux, an 18th-century French military doctor who described such a case in his book "Anecdotes de Médecine."[27] In the 19th century a few studies moved beyond individual cases - one privately done by the Mormons and one in Switzerland. Up to 2005, 95% of world cultures are known to have made some mention of NDEs.[26]

    A number of more contemporary sources report the incidence of near death experiences as:

    17% amongst critically ill patients, in nine prospective studies from four different countries.[28]
    10-20% of people who have come close to death.[11]
    Research
    Near-death studies
    Main article: Near-death studies
    Bruce Greyson (psychiatrist), Kenneth Ring (psychologist), and Michael Sabom (cardiologist), helped to launch the field of near-death studies and introduced the study of near-death experiences to the academic setting. From 1975 to 2005, some 2,500 self-reported individuals in the US had been reviewed in retrospective studies of the phenomena[26] with an additional 600 outside the US in the West,[26] and 70 in Asia.[26] Additionally, prospective studies had identified 270 individuals. Prospective studies review groups of individuals (e.g., selected emergency room patients) and then find who had an NDE during the study's time; such studies cost more to perform.[26] In all, close to 3,500 individual cases between 1975 and 2005 had been reviewed in one or another study. All these studies were carried out by some 55 researchers or teams of researchers.[26]

    Melvin Morse, head of the Institute for the Scientific Study of Consciousness, and colleagues[17][29] have investigated near-death experiences in a pediatric population.

    Clinical research in cardiac arrest patients
    Parnia 2001 study
    In 2001, Sam Parnia and colleagues published the results of a year-long study of cardiac arrest survivors that was conducted at Southampton General Hospital. 63 survivors were interviewed. They had been resuscitated after being clinically dead with no pulse, no respiration, and fixed dilated pupils. Parnia and colleagues investigated out-of-body experience claims by placing figures on suspended boards facing the ceiling, not visible from the floor. Four had experiences that, according to the study criteria, were NDEs but none of them experienced the out-of-body experience. Thus, they were not able to identify the figures.[30][5][31]

    Psychologist Chris French wrote regarding the study "unfortunately, and somewhat atypically, none of the survivors in this sample experienced an OBE".[5]

    Van Lommel's study

    Pim van Lommel
    In 2001 Pim van Lommel, a cardiologist from the Netherlands, and his team conducted a study on NDEs including 344 cardiac arrest patients who had been successfully resuscitated in 10 Dutch hospitals. Patients not reporting NDEs were used as controls for patients who did, and psychological (e.g., fear before cardiac arrest), demographic (e.g., age, sex), medical (e.g., more than one cardiopulmonary resuscitation (CPR)), and pharmacological data were compared between the two groups. The work also included a longitudinal study where the two groups (those who had had an NDE and those who had not had one) were compared at two and eight years, for life changes. One patient had a conventional out of body experience. He reported being able to watch and recall events during the time of his cardiac arrest. His claims were confirmed by hospital personnel. "This did not appear consistent with hallucinatory or illusory experiences, as the recollections were compatible with real and verifiable rather than imagined events".[31][32]

    Awareness during Resuscitation (AWARE) study
    While at University of Southampton, Parnia was the principal investigator of the AWARE Study, which was launched in 2008.[13] This study which concluded in 2012 included 33 investigators across 15 medical centers in the UK, Austria and the US and tested consciousness, memories and awareness during cardiac arrest. The accuracy of claims of visual and auditory awareness was examined using specific tests.[33] One such test consisted in installing shelves, bearing a variety of images and facing the ceiling, hence not visible by hospital staff, in rooms where cardiac-arrest patients were more likely to occur. The results of the study were published in October 2014; both the launch and the study results were widely discussed in the media.[34][35]

    A review article analyzing the results reports that, out of 2,060 cardiac arrest events, 101 of 140 cardiac arrest survivors could complete the questionnaires. Of these 101 patients 9% could be classified as near death experiences. Two more patients (2% of those completing the questionnaires) described "seeing and hearing actual events related to the period of cardiac arrest". These two patients' cardiac arrests did not occur in areas equipped with ceiling shelves hence no images could be used to objectively test for visual awareness claims. One of the two patients was too sick and the accuracy of her recount could not be verified. For the second patient, however, it was possible to verify the accuracy of the experience and to show that awareness occurred paradoxically some minutes after the heart stopped, at a time when "the brain ordinarily stops functioning and cortical activity becomes isoelectric." The experience was not compatible with an illusion, imaginary event or hallucination since visual (other than of ceiling shelves' images) and auditory awareness could be corroborated.[31]

    AWARE II
    As of May 2016, a posting at the UK Clinical Trials Gateway website described plans for AWARE II, a two-year multicenter observational study of 900-1500 patients experiencing cardiac arrest, which said that subject recruitment had started on 1 August 2014 and that the scheduled end date was 31 May 2017.[36] The study was extended, and it is currently expected to end in 2020.[37]

    Meditation-Induced NDEs
    A three-year longitudinal study has revealed that some Buddhist meditation practitioners are able to willfully induce near-death experiences at a pre-planned point in time. Unlike traditional NDEs, participants were consciously aware of experiencing the meditation-induced NDE and retained control over its content and duration.[38] The Dalai Lama has also asserted that experienced meditators can deliberately induce the NDE state during meditation, being able to recognize and sustain it.[39]

    Explanatory models
    In a review article, psychologist Chris French[5] has grouped approaches to explain NDEs in three broad groups which "are not distinct and independent, but instead show considerable overlap": spiritual theories (also called transcendental), psychological theories, and physiological theories that provide a physical explanation for NDEs.

    Spiritual or transcendental theories
    French summarizes this model by saying : "the most popular interpretation is that the NDE is exactly what it appears to be to the person having the experience".[5] The NDE would then represent evidence of the supposedly immaterial existence of a soul or mind, which would leave the body upon death. An NDE would then provide information about an immaterial world where the soul would journey upon ending its physical existence on earth.[5]

    According to Greyson[11] some NDE phenomena cannot be easily explained with our current knowledge of human physiology and psychology. For instance, at a time when they were unconscious patients could accurately describe events as well as report being able to view their bodies "from an out-of-body spatial perspective". In two different studies of patients who had survived a cardiac arrest, those who had reported leaving their bodies could describe accurately their resuscitation procedures or unexpected events, whereas others "described incorrect equipment and procedures".[11] Sam Parnia also refers to two cardiac arrest studies and one deep hypothermic circulatory arrest study where patients reported visual and/or auditory awareness occurring when their brain function had ceased. These reports "were corroborated with actual and real events".[40][31]

    Five prospective studies have been carried out, to test the accuracy of out of body perceptions by placing "unusual targets in locations likely to be seen by persons having NDEs, such as in an upper corner of a room in the emergency department, the coronary care unit, or the intensive care unit of a hospital." Twelve patients reported leaving their bodies, but unfortunately none could describe the hidden visual targets. Although this is a small sample, the failure of purported out-of-body experiencers to describe the hidden targets raises questions about the accuracy of the anecdotal reports described above.[11]

    Psychologist James Alcock has described the afterlife claims of NDE researchers as pseudoscientific. Alcock has written the spiritual or transcendental interpretation "is based on belief in search of data rather than observation in search of explanation."[41] Chris French has noted that "the survivalist approach does not appear to generate clear and testable hypotheses. Because of the vagueness and imprecision of the survivalist account, it can be made to explain any possible set of findings and is therefore unfalsifiable and unscientific."[42]

    Psychological explanations
    French summarises the main psychological explanations which include: the depersonalization, the expectancy and the dissociation models.[5]

    Depersonalization model
    A depersonalization model was proposed in the 1970s by professor of psychiatry Russell Noyes and clinical psychologist Roy Kletti, which suggested that the NDE is a form of depersonalization experienced under emotional conditions such as life-threatening danger, potentially inescapable danger, and that the NDE can best be understood as an hallucination.[5][43][44][45][46] According to this model, those who face their impending death become detached from the surroundings and their own bodies, no longer feel emotions, and experience time distortions.[11]

    This model suffers from a number of limitations to explain NDEs for subjects who do not experience a sensation of being out of their bodies; unlike NDEs, experiences are dreamlike, unpleasant and characterized by "anxiety, panic and emptiness".[11] Also, during NDEs subjects remain very lucid of their identities, their sense of identity is not changed unlike those experiencing depersonalization.[11]

    Expectancy model
    Another psychological theory is called the expectancy model. It has been suggested that although these experiences could appear very real, they had actually been constructed in the mind, either consciously or subconsciously, in response to the stress of an encounter with death (or perceived encounter with death), and did not correspond to a real event. In a way, they are similar to wish-fulfillment: because someone thought they were about to die, they experienced certain things in accordance with what they expected or wanted to occur. Imagining a heavenly place was in effect a way for them to soothe themselves through the stress of knowing that they were close to death.[5] Subjects use their own personal and cultural expectations to imagine a scenario that would protect them against an imminent threat to their lives.[11]

    Subjects' accounts often differed from their own "religious and personal expectations regarding death" which contradicts the hypothesis they may have imagined a scenario based on their cultural and personal background.[11]

    Although the term NDE was first coined in 1975 and the experience first described then, recent descriptions of NDEs do not differ from those reported earlier than 1975. The only exception is the more frequent description of a tunnel. Hence, the fact that information about these experiences could be more easily obtained after 1975, did not influence people's reports of the experiences.[11]

    Another flaw of this model can be found in children's accounts of NDEs. These are similar to adults', and this despite children being less affected by religious or cultural influences about death.[11]

    Dissociation model
    The dissociation model proposes that NDE is a form of withdrawal to protect an individual from a stressful event. Under extreme circumstances some people may detach from certain unwanted feelings in order to avoid experiencing their emotional impact and suffering associated with them. The person also detaches from one's immediate surroundings.[5]

    Birth model
    The birth model suggests that near death experiences could be a form of reliving the trauma of birth. Since a baby travels from the darkness of the womb to light and is greeted by the love and warmth of the nursing and medical staff, and so, it was proposed, the dying brain could be recreating the passage through a tunnel to light, warmth and affection.[5]

    Reports of leaving the body through a tunnel are equally frequent among subjects who were born by cesarean section and natural birth. Also, newborns do not possess "the visual acuity, spatial stability of their visual images, mental alertness, and cortical coding capacity to register memories of the birth experience".[11]

    Physiological explanations (organic theories)
    A wide range of physiological theories of the NDE have been put forward including those based upon cerebral hypoxia, anoxia, and hypercapnia; endorphins and other neurotransmitters; and abnormal activity in the temporal lobes.[5]

    Neurobiological factors in the experience have been investigated by researchers in the field of medical science and psychiatry.[47] Among the researchers and commentators who tend to emphasize a naturalistic and neurological base for the experience are the British psychologist Susan Blackmore (1993), with her "dying brain hypothesis".[48]

    Neuroanatomical models
    Neuroscientists Olaf Blanke and Sebastian Dieguez (2009),[49] from the Ecole Polytechnique Fédérale de Lausanne, Switzerland, propose a brain based model with two types of NDEs :

    "type 1 NDEs are due to bilateral frontal and occipital, but predominantly right hemispheric brain damage affecting the right temporal parietal junction and characterized by out of body experiences, altered sense of time, sensations of flying, lightness vection and flying"[6]
    "type 2 NDEs are also due to bilateral frontal and occipital, but predominantly left hemispheric brain damage affecting the left temporal parietal junction and characterized by feeling of a presence, meeting and communication with spirits, seeing of glowing bodies, as well as voices, sounds, and music without vection"[6]
    They suggest that damage to the bilateral occipital cortex may lead to visual features of NDEs such as seeing a tunnel or lights, and "damage to unilateral or bilateral temporal lobe structures such as the hippocampus and amygdala" may lead to emotional experiences, memory flashbacks or a life review. They concluded that future neuroscientific studies are likely to reveal the neuroanatomical basis of the NDE which will lead to the demystification of the subject without needing paranormal explanations.[6]


    Animation of the human left temporal lobe
    French has written that the "temporal lobe is almost certain to be involved in NDEs, given that both damage to and direct cortical stimulation of this area are known to produce a number of experiences corresponding to those of the NDE, including OBEs, hallucinations, and memory flashbacks".[5]

    Vanhaudenhuyse et al. 2009 reported that recent studies employing deep brain stimulation and neuroimaging have demonstrated that out-of-body experiences result from a deficient multisensory integration at the temporoparietal junction and that ongoing studies aim to further identify the functional neuroanatomy of near-death experiences by means of standardized EEG recordings.[50]

    According to Greyson[11] multiple neuroanatomical models have been proposed where NDEs have been hypothesized to originate from different anatomical areas of the brain, namely: the limbic system, the hippocampus, the left temporal lobe, Reissen's fiber in the central canal of the spinal cord, the prefrontal cortex, the right temporal lobe.

    Blanke et al.[6] admit that their model remains speculative to the lack of data. Likewise Greyson[11] writes that although some or any of the neuroanatomical models proposed may serve to explain NDEs and pathways through which they are expressed, they remain speculative at this stage since they have not been tested in empirical studies.[11]

    Neurochemical models
    Some theories hypothesize that drugs used during resuscitation induced NDEs, for example, ketamine or as resulting from endogeneous chemicals that transmit signals between brain cells, neurotransmitters:[5]

    In the early eighties, Daniel Carr wrote that the NDE has characteristics that are suggestive of a limbic lobe syndrome and that the NDE can be explained by the release of endorphins and enkephalins in the brain.[51][52] Endorphins are endogenous molecules "released in times of stress and lead to a reduction in pain perception and a pleasant, even blissful, emotional state."[5]
    Judson and Wiltshaw (1983) noted how the administration of endorphin-blocking agents such as naloxone had been occasionally reported to produce "hellish" NDEs.[53] This would be coherent with endorphins' role in causing a "positive emotional tone of most NDEs".[5]
    Morse et al. 1989 proposed a model arguing that serotonin played a more important role than endorphins in generating NDEs.[54] "at least with respect to mystical hallucinations and OBEs".[5]
    According to Parnia, neurochemical models are not backed by data. This is true for "NMDA receptor activation, serotonin, and endorphin release" models.[31] Parnia writes that no data has been collected via thorough and careful experimentation to back "a possible causal relationship or even an association" between neurochemical agents and NDE experiences.[40]

    Multi-factorial models
    The first formal neurobiological model for NDE, included endorphins, neurotransmitters of the limbic system, the temporal lobe and other parts of the brain.[55] Extensions and variations of their model came from other scientists such as Louis Appleby (1989).[56]

    Other authors suggest that all components of near-death experiences can be explained in their entirety via psychological or neurophysiological mechanisms, although the authors admit that these hypotheses have to be tested by science.[57]

    Low oxygen levels (and G-LOC) model
    Low oxygen levels in the blood (hypoxia or anoxia) have been hypothesized to induce hallucinations and hence possibly explain NDEs.[15][5] This is because low oxygen levels characterize life-threatening situations and also by the apparent similarities between NDEs and G-force induced loss of consciousness (G-LOC) episodes.

    These episodes are observed with fighter pilots experiencing very rapid and intense acceleration that result in lack of sufficient blood supply to the brain. Whinnery[58] studied almost 1000 cases and noted how the experiences often involved "tunnel vision and bright lights, floating sensations, automatic movement, autoscopy, OBEs, not wanting to be disturbed, paralysis, vivid dreamlets of beautiful places, pleasurable sensations, psychological alterations of euphoria and dissociation, inclusion of friends and family, inclusion of prior memories and thoughts, the experience being very memorable (when it can be remembered), confabulation, and a strong urge to understand the experience."[5][58]

    However, hypoxia-induced acceleration's primary characteristics are "rythmic jerking of the limbs, compromised memory of events just prior to the onset of unconsciousness, tingling of extremities ..." that are not observed during NDEs.[15] Also G-LOC episodes do not feature life reviews, mystical experiences and "long-lasting transformational aftereffects", although this may be due to the fact that subjects have no expectation of dying.[5]

    Also, hypoxic hallucinations are characterized by "distress and agitation" and this is very different from near death experiences which subjects report as being pleasant.[11]

    Altered blood gas levels models
    Some investigators have studied whether hypercarbia or higher than normal carbon dioxide levels, could explain the occurrence of NDEs. However, studies are difficult to interpret since NDEs have been observed both with increased levels as well as decreased levels of carbon dioxide, and finally some other studies have observed NDEs when levels had not changed, and there is little data.[15]

    Other models
    French said that at least some reports of NDEs might be based upon false memories.[59]

    According to Engmann (2008) near-death experiences of people who are clinically dead are psychopathological symptoms caused by a severe malfunction of the brain resulting from the cessation of cerebral blood circulation.[60] An important question is whether it is possible to "translate" the bloomy experiences of the reanimated survivors into psychopathologically basic phenomena, e.g., acoasms (nonverbal auditory hallucinations), central narrowing of the visual field, autoscopia, visual hallucinations, activation of limbic and memory structures according to Moody's stages. The symptoms suppose a primary affliction of the occipital and temporal cortices under clinical death. This basis could be congruent with the thesis of pathoclisis—the inclination of special parts of the brain to be the first to be damaged in case of disease, lack of oxygen, or malnutrition—established eighty years ago by Cécile and Oskar Vogt.[61]

    Professor of neurology Terence Hines (2003) claimed that near-death experiences are hallucinations caused by cerebral anoxia, drugs, or brain damage.[62]

    Cross-cultural aspects
    Gregory Shushan published an analysis of the afterlife beliefs of five ancient civilisations (Old and Middle Kingdom Egypt, Sumerian and Old Babylonian Mesopotamia, Vedic India, pre-Buddhist China, and pre-Columbian Mesoamerica) and compared them with historical and contemporary reports of near-death experiences, and shamanic afterlife "journeys". Shushan found similarities across time, place, and culture that he found could not be explained by coincidence; he also found elements that were specific to cultures; Shushan concludes that some form of mutual influence between experiences of an afterlife and culture probably influence one another and that this inheritance in turn influences individual NDEs.[63] In contrast, it has been argued that near-death experiences and many of their elements (vision of God, judgment, the tunnel, or the life review) are closely related to religious and spiritual traditions of the West. It was mainly Christian visionaries, Spiritualists, Occultists, and Theosophists of the 19th and 20th century that reported them (Schlieter 2018).

    According to Parnia, near death experiences' interpretations are influenced by religious, social, cultural backgrounds. However, the core elements appear to transcend borders and can be considered universal. In fact, some of these core elements have even been reported by children <3 years old (this occurred over many months, whilst playing and communicated using children's language). In other words, at an age where they should not have been influenced by culture or tradition.[31]

    Also, according to Greyson,[11] the central features of NDEs are universal and have not been influenced by time. These have been observed throughout history and in different cultures. These notwithstanding, cultural influences have probably played a role in some NDEs' reported descriptions.
  35. 37
    Tomas55555

    24 ročný chalan

    @karlotiskot

    Neodpovedal si mi, pýtal som sa ťa prečo majú všetci kresťania rovnaké obsahovo rovnaké, podobné zážitky ? Pri snoch totiž nejde o rovnaké zážitky, ale každý sen sa obsahovo líší.

    Naschvál som ti dával otázky na video ktoré si posielal, a na ten dlhý lin k na wiki pretože som zistoval či máš o danej veci aspon niečo naštudované, ale ako som sa presvedčil nemáš o tom naštudované ani za štipku. Hmm, to naozaj odo mna očakávaš že od takéhoto človeka budem čítať dokument ktorý je na mesiac čítania, a kde sa s najväčšou pravdepodobnostou ani nenachádza informácia ktorú hladám. Pekne si sa vykrútil, nemáš protiargumenty a preto aby si nemusel odpovedať mi tu dáš link na stostranový dokument. Namiesto toho aby si mi zopár vetami zhrnul to o čom sa v linku píše, ma tu odkazuješ na 100 stranový dokument. To naozaj očakávaš že som tak naivný ?
  36. 38
    Karlotiskot

    34 ročný ujo
    I'll Be In The Garage

    @tomas55555 Šak je tam tá odpoveď :D Čítaj a dozvieš sa fakt drsné veci o ktorých si očividne nikdy nikdajs nechyroval :D :D

    Bla bla bla kecáš kokotiny, ktorými ospravedlňuješ, že si trubka, čo je lenivá si niečo zistiť o vlastnej gebuli. A ano presne o tom to je. Ze len o zakladoch mozgu to mas na mesiac citania :D Ty si tomu za 24 rokov ten mesiac zivota nedal, ale bol si schopny zromazdit cez stovku vypovedi a nakoniec chceš odomňa aby som ti to pár vetami zhrnul - no to výš že jo :D Mozno ti to raz vysvetli ucitel a ty to pochopis :D
  37. 39
    Tomas55555

    24 ročný chalan

    @karlotiskot

    Iste ja som lenivý, a to hovorí ten kto si nevedel pozrieť ani jedno 10 minutové video ktoré mi poslal, a odo mna očakáva pozrieť si dokument o dlžke jedneho mesiaca.............................................

    Ty tvrdíš že to máš preštudované, prečo mi teda nemožeš vysvetliť prečo sú krestanske svedectvá halucinaciou. Namiesto tých urážok a vyhovárania si to už mohol dávno vysvetliť, ale ty to nechceš vysvetliť pretože si to ani nikdy nečítal a preštudované to nemáš, alebo to preštudované máš ale žiaden protiargument to neobsahuje.
  38. 40
    Lukaso121

    29 ročný muž
    Nitra

    Zase si cital len obsah lahodny tvojmu oku , skus teraz kritiku na tie veci , ale sa pozri na svedectva inych nabozenskych skupin o ich bohovi a vylúcis tym vsetky
  39. 41
    Karlotiskot

    34 ročný ujo
    I'll Be In The Garage

    Ja ti to predsa nevysvetlujem z jasného dovodu - lebo si kokot. Ale dosad si tam co chces. :D
    Ale hej hej dokazal si existenciu Boha :D tu na birdzi, svedectvami z netu :D chces aj nejaky veniec okolo krku? Mam totiž len kakaovy :D
  40. 42
    Riddiculus

    7 ročné dievča
    Pche.

    Podľa mňa fórum,ktoré nemá zmysel. Zase jeden verí, druhý nie. A kde je pravda?
    Ďaleko za hádkami týchto dvoch sa aj tak nedostanú k vzájomnej tolerancii...
  41. 43
    Turbolienka123

    20 ročné dievča

    Tak to je na každom, či týmto veciam bude veriť. Ja si osobne myslím, že Boh je jeden a ten istý pre každé náboženstvo iba s tým rozdielom, že niektorí ho volajú inak a inak si vykladajú to, čo od nás chce. Ja, nakoľko som kresťanska katolíčka, snažím sa pridržiavať pravidiel, ktoré má toto náboženstvo, avšak ak je niekto moslim a pridržiava sa svojich pravidiel, dostane sa do toho istého neba ako ostatní s tým, že to konkrétne nebo iba pomenuje inak, prípadne bude mať inú predstavu o ňom ako my.
    Ja som voči svedectvám trocha skeptická. Určite si myslím, že sú tie veci reálne, čo tí ľudia videli, no zároveň môžu byť aj ľudia, ktorí si to vymyslia.
  42. 44
    Screamose

    tvári sa, že má -1 roky

    Ludia pekne ste dali tomu hajzlovi :D Mam z vas radost :)
  43. 45
    Vreskot000

    32 ročný muž

    na svedectvá o nebi a pekle ti poviem toľko, že otvor si Písmo sväté, a svojím životom sa snaž vydať o Ňom, teda o Pánu Bohu svedectvo. Zas je to o tom, čo sa komu snívalo, zjavilo a neviem čo. Diskutujúcich nezaujíma, čo sa komu niečo zdalo, snívalo a neviem aké halucinácie mali, pretože oni tomu neveria. Diskutuješ si si nesprávnymi ľuďmi, ktorí nechcú prísť k pravde. Takto v podstate aj ty istou mierou podnecuješ niektorých k tomu, aby písali veci, ktoré môžu napríklad urážať alebo iným spôsobom dehonestovať kresťanstvo, vieru v Boha, prípadne v hlbšej miere kto ku akej cirkvi patrí a podobne. Myslím si, že keby si sa zaoberal nejakou serióznou prácou, zistil by si, že ty jediné čo potrebuješ, je veriť v Boha, modliť sa, a plniť to, čo je napísané v biblii, dobrorečiť aj nepriateľom. A neviem presne či to my kresťania robíme. Niekedy je lepšie mlčať, ako prehovoriť, pretože v tom mlčaní sa paradoxne vyjadruje všetko bez slov. Áno, bez slov sa vyjadruje pravda, na ktorú skôr či neskôr prídu všetci, len niektorí budú zaradostení, a niektorí budú zahanbení naveky. Teraz to samozrejme nechcem robiť akúsi exegézu Zjavenia sv. apoštola Jána, ale to, že Pán Boh predsa ty dobre taktiež to vieš, vymeriava nám všetkým istý časový úsek na tejto zemi, a nikdy nevieš, kedy bude prerušený tým, že nás povolá. Ťažko to povedať. Ja svedectvám o nebi a pekle neverím, pretože moja viera mi to nekáže, a nebudem robiť niečo, čo mi nekáže a možno pochybuje moja viera. Pre mňa je autorita Písmo Sväté. Skôr ma desí biblický príbeh o lazárovi a boháčovi, ktorý jeden sa doprosuje milosti, a druhý je v abrahámovom lone šťastný. ako teda žijeme, a kde smerujeme si môžeš položiť také zamyslenie nielen pri nedeľnom čítaní Písma Svätého v cirkvi ktorej sa nachádzaš, alebo individuálne, kedy možno rozjímaš a čítaš o Písme Svätom. A kto to robí s posvätnou úctou, bázňou, s láskou k Ježišovi a ľuďom, ktorí sú okolo jeho, a ide z neho dobrota, láska, mier, všetky kresťanské čnosti, síce to neznamená, že to v duchovnom živote v akomsi duchovnom boji má vyhraté, avšak približuje sa bližšie k Bohu. Snáď najkrajšie to vyjadruje svetoznáma pieseň, ktorú poznajú kresťania mnohých denominácii, a to nielen kresťania, ale aj ateisti, a pieseň sa volá Bliž k tebe Bože môj. Citujem. Nádherný svitne deň koniec už tmám. Z tvrdých skál skúšok ti postavím chrám. V plameňoch obetí, duch môj rád zaletí, bližšie vždy k tebe len, o Bože môj. Ako vidíš v tejto poslednej, menej známej strofy krásnej piesne Blíž k tebe bože môj je vysvetlené v podstate všetko, a je tu aj odpoveď na to, čím sa už aj ty na tomto webe dlhšiu dobu zaoberáš. Len toľko som ti chcel napísať. mier.