Consciousness after death

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The question of consciousness after death is a common theme in society and culture. Across the ancient world, most ethnic groups held afterlife beliefs about preservation of consciousness after the death of the physical body. Following the advent of scientific method, consciousness has been associated with physiological function of the brain, whose cessation of function defines death. However, many people continue to believe in some form of consciousness after death, and this is a feature of many religious belief systems.

Neuropsychology[edit]

According to neuropsychology, the mind or psyche, as well as consciousness and personality, is a product of the functioning brain.[1] During brain death, all brain function halts permanently. The implication is that the mind fails to survive brain death and ceases to exist.[2][3]

Individual cases in which brain functioning has been disrupted have been used to support this point of view. In the case of Phineas Gage, a 25-year-old man survived destruction of one or both frontal lobes by a projectile iron rod and went on to manifest pronounced changes in personality, suggesting a correlation between brain states and mental states.[4] Similar examples abound; neuroscientist David Eagleman describes the case of another individual who exhibited escalating pedophilic tendencies at two different times, and in each case was found to have tumors growing in a particular part of his brain.[5][6] The amygdala processes reactions to violations concerning personal space, and these reactions are absent in persons in whom the amygdala is damaged bilaterally.[7] Monkey mothers who have amygdala damage show a reduction in maternal behaviors towards their infants, often physically abusing or neglecting them.[8] The acquisition of memory and knowledge has a bio-chemical basis.[1] Psychopharmaceuticals can be used to temporarily alter the mind through manipulation of neurotransmission. Visual perception is handled by the occipital lobe, which once damaged often leads to blindness (see cortical visual impairment). The insular and the cingulate cortices, especially, are involved in consciousness and self-awareness. Also, see lobotomy.

In addition, neuropsychology links mental development in individual organisms with brain development. In intelligent animals, human and non-human alike, consciousness as we know it begins to appear at neonatal stages,[9] is lost and recovered sporadically in the course of their lifespan—during deep sleep, syncope and sometimes coma, as lack of communication between cerebral neurons—and is lost permanently once their brains are dead. Brain death is a chronic disorder of consciousness characterized by lack of response to external stimuli, lack of observed activity and lack of observed behavior.

In the process of clinical death, the heart stops working and pumping blood to the brain, thereby cutting the brain's essential supply of oxygen and of other less urgent nutrients. In dogs, measurable brain activity ends within 20 to 40 seconds.[10] As characteristic of all biological cells, brain cells die once deprived of oxygenated blood, destroying the brain.

Alternative viewpoints[edit]

Near-death experiences (NDEs)[edit]

Some people who have undergone cardiopulmonary resuscitation report experiencing such sensations as detachment from the body, feelings of levitation, and the presence of a light, happening after cardiac arrest. These are commonly referred to as near-death experiences or NDEs by those who study such phenomenon. It has been suggested (e.g., by David Fontana[11]) that NDEs indicate postmortem consciousness.[12][13] Sam Parnia comments that consciousness isn't disrupted immediately after clinical death and describes the process of death as "essentially a global stroke of the brain. Therefore, like any stroke process one would not expect the entity of mind/consciousness to be lost immediately."[14]

Stuart Hameroff and Deepak Chopra suggest that at death or during NDE, "it is conceivable that the quantum information which constitutes consciousness could shift to deeper planes and continue to exist purely in space-time geometry, outside the brain, distributed nonlocally", as a "quantum soul" apart from the body.[15]

In 2008, academic neurosurgeon Eben Alexander had an NDE while attached to an electroencephalogram which demonstrated a total lack of neural activity. After resuscitation, he found he was able to identify the face of a deceased biological sister whom he had previously not known existed (he had been raised in an adoptive family). Prior to his NDE, Alexander had been non-religious. Afterwards, he gained a definite belief in the existence of an afterlife, and went on to write a book about his life-altering experience. Alexander states that the elaborate, highly detailed, and even prescient experiences he had while his brain activity was clinically non-existent provide definitive proof that consciousness can exist without the need for a functional brain.[16]

Sam Harris, Oliver Sacks, and Michael Shermer have pointed out that it is not entirely clear that Dr. Alexander had the experience during coma. They argue that the experience could have occurred when he was returning from the coma, while his neocortex was coming back "online" and returning to full function. Further criticisms include contesting the claim that the coma led to complete neural inactivity.[17][18][19]

Such near-death experiences have been described in medical journals as hallucinatory, and such prescient information supposedly gained from NDEs as merely coincidental and dubious.[20][21][22] Ketamine, a dissociative hallucinogen, has been shown to replicate compounds of near-death experiences.[23][24][25] Lucid dreaming too induces experiences quite similar to those of NDEs.[26][27] The imagery in NDEs varies within cultures.[28][29][30] Rick Strassman advanced the hypothesis that a massive release of the psychedelic dimethyltryptamine (DMT) from the pineal gland prior to death or near-death was the cause of the near-death experience phenomenon.[31][32][33]

See also[edit]

References[edit]

  1. ^ a b Rosenberger, Peter B. MD; Adams, Heather R. PhD. Big Brain/Smart Brain. 18th October, 2011.
  2. ^ Piccinini, Gualtiero; Bahar, Sonya. "No Mental Life after Brain Death: The Argument from the Neural Localization of Mental Functions" (2011). University of Missouri - St. Louis.
  3. ^ Bernat JL (8 Apr 2006). "Chronic disorders of consciousness". Lancet 367 (9517): 1181–1192. doi:10.1016/S0140-6736(06)68508-5. PMID 16616561. 
  4. ^ Harlow (1868), pp. 339–342.
  5. ^ "Brain tumour causes uncontrollable paedophilia"
  6. ^ Eagleman, Philosophy Bites Podcast, "David Eagleman on Morality and the Brain"
  7. ^ Kennedy DP, Gläscher J, Tyszka JM, Adolphs R (2009). "Personal space regulation by the human amygdala". Nat Neurosci 12 (10): 1226–1227. doi:10.1038/nn.2381. PMC 2753689. PMID 19718035. 
  8. ^ Bucher, K., Myersn, R., Southwick, C. (1970). "Anterior temporal cortex and maternal behaviour in monkey". Neurology 20 (4): 415. PMID 4998075. 
  9. ^ H., Lagercrantz; JP., Changeux. (2009). "The emergence of human consciousness: from fetal to neonatal life". Pediatric research 65 (3): 255–60. doi:10.1203/PDR.0b013e3181973b0d. PMID 19092726. 
  10. ^ Lind B et al., B; Snyder, J; Kampschulte, S; Safar, P (1975). "A review of total brain ischaemia models in dogs and original experiments on clamping the aorta". Resuscitation (Elsevier) 4 (1): 19–31. doi:10.1016/0300-9572(75)90061-1. PMID 1188189. 
  11. ^ Fontana, David (Cardiff University and Liverpool John Moores University), Does Mind Survive Physical Death?, 2003
  12. ^ Grossman, Neil (Indiana University and University of Illinois), Who's Afraid of Life After Death? Why NDE Evidence is Ignored, Institute of Noetic Sciences (IONS), 2002
  13. ^ Carter, Chris: Science and the Near-Death Experience: How Consciousness Survives Death (2010). Toronto, Inner Traditions. ISBN 1-59477-356-4
  14. ^ AWARE - Update from Dr. Parnia
  15. ^ Hameroff, S., and Chopra, D. (2012). The "Quantum Soul": A Scientific Hypothesis. In Alexander Moreira-Almeida and Franklin Santana Santos (Eds.), Exploring Frontiers of the Mind-Brain Relationship (Mindfulness in Behavioral Health (ch. 5). New York: Springer. Reprint
  16. ^ Alexander, Eben. (2012). Proof of Heaven: A Neurosurgeon's Journey into the Afterlife. Simon & Schuster
  17. ^ Harris, Sam (12 October 2012). "This Must Be Heaven". Retrieved 28 July 2013. 
  18. ^ Shermer, Michael (April 2013). "Proof of Hallucination". Retrieved 28 July 2013. 
  19. ^ Sacks, Oliver (12 December 2012). "Seeing God in the Third Millennium". Retrieved 28 July 2013. 
  20. ^ Buzzi, Giorgio. "Correspondence: Near-Death Experiences." Lancet. Vol. 359, Issue 9323 (June 15, 2002): 2116-2117.
  21. ^ Britton, Willoughby B. and Richard R. Bootzin. "Near-Death Experiences and the Temporal Lobe." Psychological Science. Vol. 15, No. 4 (April 2004): 254-258.
  22. ^ Blackmore, Susan: Dying to Live: Near-Death Experiences (1993). London, Grafton.
  23. ^ Jansen, Karl L. R. (1995) Using ketamine to induce the near-death experience: mechanism of action and therapeutic potential. Yearbook for Ethnomedicine and the Study of Consciousness (Jahrbuch furr Ethnomedizin und Bewubtseinsforschung) Issue 4 pp55–81.
  24. ^ Jansen, Karl L. R. (1997) The Ketamine Model of the Near Death Experience: A central role for the NMDA Receptor. Journal of Near-Death Studies Vol. 16, No.1
  25. ^ Ring, Kenneth. Ketamine - Near Death and Near Birth Experiences Dr Karl Jansen
  26. ^ Green, J. Timothy (1995). "Lucid dreams as one method of replicating components of the near-death experience in a laboratory setting". Journal-of-Near-Death-Studies 14: 49. "A large phenomenological overlap among lucid dreams, out-of-body experiences, and near-death experiences suggests the possibility of developing a methodology of replicating components of the near-death experience using newly developed methods of inducing lucid dreams. Reports on the literature of both spontaneous and induced near-death-experience-like episodes during lucid dreams suggest a possible protocol." 
  27. ^ Lynne Levitan; Stephen LaBerge (1991). "Other Worlds: Out-of-Body Experiences and Lucid Dreams". Nightlight (The Lucidity Institute) 3 (2-3). 
  28. ^ Near-Death and Out-of-Body Experiences in a Melanesian Society by Dorothy E. Counts]
  29. ^ Varieties of NDE
  30. ^ Eleven Thai Near-Death Experiences
  31. ^ Rick Strassman (with Slawek Wojtowicz, Luis Eduardo Luna and Ede Frecska), "Inner Paths to Outer Space: Journeys to Alien Worlds through Psychedelics and Other Spiritual Technologies", 376 pages, Park Street Press, 2008, ISBN 978-1-59477-224-5
  32. ^ Rick Strassman, DMT: The Spirit Molecule: A Doctor's Revolutionary Research into the Biology of Near-Death and Mystical Experiences, 320 pages, Park Street Press, 2001, ISBN 0-89281-927-8
  33. ^ Rick Strassman, Hallucinogens (chapter), in Mind-Altering Drugs: The Science Of Subjective Experience, 402 pages, Oxford University Press, 2005, ISBN 0-19-516531-4