Transcript Near Death Experiences - UCSD Cognitive Science

Near Death Experiences
(NDE)
Presented by
Jennifer Kwok
Jennifer Tom
Luong Phan
What is the near death experience?

Occurs when a person enters “clinical
death” and usually has a profound personal
experience which can include:
What is the near death experience?


Occurs when a person enters “clinical
death” and usually has a profound personal
experience which can include:
A sensation of leaving the body
What is the near death experience?



Occurs when a person enters “clinical
death” and usually has a profound personal
experience which can include:
A sensation of leaving the body
Following a bright light
What is the near death experience?




Occurs when a person enters “clinical
death” and usually has a profound personal
experience which can include:
A sensation of leaving the body
Following a bright light
Encounter with a higher being (God,
Buddha, Aliens, etc.)
Background Information

What is “clinical death” then?
Background Information


What is “clinical death” then?
Clinical death: no cardiac output, no
respiration, fixed dilated pupils
Background Information
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What is “clinical death” then?
Clinical death: no cardiac output, no
respiration, fixed dilated pupils
Focus of our research evidence are
centered on cardiac arrest patients
because they all exhibit clinical death
Background Information
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Raymond Moody (1975)
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Wrote Life After Life
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First compilation of NDE survivor stories
Coined the term “near death experience”
Background Information

Why care about NDE?
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NDE have been recorded through history and in
many different cultures.
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Description of Er’s experience in Plato’s Republic
resemble modern NDEs.
Best chance to study death because these
patients return from “dying”
Theorized Causes

Disturbance of brain chemistry (Parnia
2001)
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alpha-endopsychosin, hypoxia, NDMA, etc.
Theorized Causes

Disturbance of brain chemistry (Parnia
2001)


alpha-endopsychosin, hypoxia, NDMA, etc.
Psychological response to perceived threat
of death (Parnia 2001)

Wish fulfillment in response to perceived threat of
death
Theorized Causes

REM intrusion (Nelson 2006)
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When things normally experienced during sleep
carry over into wakefulness
Theorized Causes
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REM intrusion (Nelson 2006)
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When things normally experienced during sleep
carry over into wakefulness
Usually occurs before sleep or just after
wakefulness
Theorized Causes
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REM intrusion (Nelson 2006)
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When things normally experienced during sleep
carry over into wakefulness
Usually occurs before sleep or just after
wakefulness
Occurs in times of extreme stress in which one
may be in REM sleep and partially awake at the
same time
Theorized Causes: REM Int. Cont’
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REM centers in the brainstem
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Higher brain areas in the cortex quickly blank out
during hypoxia, the brainstem (since it’s more
primitive) remains active for several minutes
Theorized Causes: REM Int. Cont’

REM centers in the brainstem
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Higher brain areas in the cortex quickly blank
out during hypoxia, the brainstem (since it’s
more primitive) remains active for several
minutes
An NDE that seems to last many minutes might
occur in the few seconds right before or right
after the cortex blanks out
Theorized Causes: REM Int. Cont’

REM centers in the brainstem
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Higher brain areas in the cortex quickly blank
out during hypoxia, the brainstem (since it’s
more primitive) remains active for several
minutes
An NDE that seems to last many minutes might
occur in the few seconds right before or right
after the cortex blanks out
NDE may also be very brief but be perceived as
prolong because REM compresses time
Theorized Causes: REM Int. Cont’
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Vagus nerve: A cranial nerve that connects the
brainstem to the heart and lungs
REM intrusion and the vagus nerve (Fox 2006)
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In times of extreme stress (heart attacks or near
drowning) blood pressure or blood oxygen levels quickly
drop, or levels of carbon dioxide in the blood quickly rise.
This stimulates the vague nerve
Since the REM centers are in the brainstem, this causes
the REM centers to snap on without warning
Theorized Causes: REM Int. Cont’
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Evidence for vagus nerve in REM intrusion (Fox
2006)
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Animal studies
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When electrically stimulating the vagus nerve in various
animal preparations, stimulation enhances REM and causes
atonia
Stimulating the vagus nerve in cats pushes them into REM
sleep within 45 seconds
Human studies
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Epilepsy patients whose condition is treated with implants
stimulate their vagus nerve also slip more quickly into REM
during daytime naps
Theorized Causes: REM Int. Cont’
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Temporal-parietal junction (Fox 2006)
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Known to cause out-of-body sensations when it
malfunctions
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Since it is located at the end of a tree of blood
vessels, if blood pressure drops, perfusion in this
area is first to go
Thus if blood pressure drops when one is fainting,
this explains why they may experience NDE-like
symptoms
Theorized Causes: REM Int. Cont’
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Could be possible that NDE enhances
subsequent REM intrusion
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SUPPORTED by: people with Post Traumatic
Stress Disorder subsequently have more
frequent REM intrusion
Evidence: REM intrusion and NDE
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REM intrusion during wakefulness is a
normal occurrence but infrequently
recognized (Nelson 2005)
Evidence: REM intrusion and NDE
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REM intrusion during wakefulness is a
normal occurrence but infrequently
recognized (Nelson 2005)
Underlies other clinical conditions such as
narcolepsy
Evidence: REM intrusion and NDE
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Common feature of narcolepsy
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Neurological disorder characterized by
uncontrollable bouts of sleep that can cause
elaborate hallucinations and out-of-body
experiences
Evidence: REM intrusion and NDE
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Common feature of narcolepsy
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Neurological disorder characterized by
uncontrollable bouts of sleep that can cause
elaborate hallucinations and out-of-body
experiences
Narcoleptics’ REM systems can activate leading
to out of body experiences
Evidence: REM intrusion and NDE
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Common feature of narcolepsy
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Neurological disorder characterized by
uncontrollable bouts of sleep that can cause
elaborate hallucinations and out-of-body
experiences
Narcoleptics’ REM systems can activate leading
to out of body experiences
Combination of dreaming and wakefulness
causes people with narcolepsy to recall their
hallucinations vividly
Evidence: REM intrusion and NDE
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Another form of REM intrusion is sleep
paralysis
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Awaken with part of brain still in REM sleep so
body feel paralyzed
Result: terrified that you’re unable to move,
visual/auditory hallucinations, and pressure on
the chest
Evidence: REM intrusion and NDE
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Nelson: surveyed of REM intrusion: 55 people
who had NDE from a variety of situations and 55
controls matched for age and gender
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Found that around 60% of NDE group reported having
experiencing some kind of symptoms of REM intrusion,
either before or after their NDE, compared with just 24 %
of the control
REM intrusions in NDE group were more elaborate (not
just sleep paralysis but also hallucinations
Evidence: REM intrusion and NDE
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Nelson: surveyed of REM intrusion: 55 people
who had NDE from a variety of situations and 55
controls matched for age and gender
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Not conclusive but good preliminary correlational
experience
Not conclusive because possible that REM intrusion
makes you more susceptible to NDE; also suggests that
you do not need to have a near-death experience to have
NDE
Why NDE is an ASC
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NDE is a deviation from the normal waking
state
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Experience clinical death
Experience another reality
Large population can experience NDE
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Prevalence of REM intrusion
10% cardiac arrest patients develop memories
consistent with NDE
 What about the other 90%? Still experience but don’t
remember?
References
Bosveld, Jane. "Soul Search: Can Science Ever Decipher the Secrets of the Human Soul?" Discover
magazine, June 2007.
Fox, Douglas. "Light at the End of the Tunnel." New Scientist. Retrieved from the web,
http://www.newscientist.com, 2008 March 3.
Nelson, Kevin R., MD et al (2006). Does the arousal system contribute to near death experience? Neurology,
66:1003-1009.
Parnia, Sam et al (2001). A qualitative and quantitative study of the incidence, features and aetiology of near
death experiences in cardiac arrest survivors. Resuscitation, 48:149-156.
Parnia, Sam and Peter Fenwick (2002). Near death experiences in cardiac arrest: visions of a dying brain or
visions of a new science of consciousness. Resuscitation, 52:5-11.
Wallace, Benjamin and Leslie E. Fisher. Consciousness and Behavior, Fourth Edition. Waveland Press Inc.,
Prospect Heights, pp. 218-220.