Conference hydra::dejavu

737.0. "Visions from Dying Brain (New Scientist)" by MILVAX::MENEZES () Fri May 13 1988 13:04

    New Scientist, 5 May 1988
    Edition No 1611
    "Visions from the dying brain"
    By Dr. Susan Blackmore (works in the brain and perception laboratory
    at the medical school of the University of Bristol, Britain)
    
    [Extract; typed without permission from publication]:
             When people come close to death and later recover, they
    tend to describe a well-structured set of experiences (e.g. seeing
    a light at the end of a tunnel)... Such experiences also tend to
    take somewhat different forms in different cultures. For example,
    in India people more often meet up with some kind of messenger who
    consults a list of names and concludes that the wrong person has
    been called up - a reprieve is given. For Christians, the being of
    light is sometimes seen as Jesus, the angel Gabriel or even St.
    Peter at his gates... So how can we explain tunnels, out-of-body
    experiences and life transformations? In classic occult lore, there
    is "astral projection". The tunnel is the transition between astral
    and etheric worlds. Carl Sagan wrote that the tunnel is "really"
    the experience we all share at birth (the tunnel being the birth
    canal); yet people born with Caesarean sections experience similar
    phenomenon.  
    
    The visual cortex of the brain, which processes both vision and
    visual imagination, is usually in a stable state; it is kept that
    way to a large extent by some neurons inhibiting others. Many of
    the conditions that produce hallucinations are those which reduce
    or interfere with inhibition... Jack Cowan, a neurobiologist from
    the University of Chicago argued an analogy with fluid mechanics
    - an increase in cortical excitability would destabilise the uniform
    state and induce stripes of activity which propagate through visual
    cortex.  The perception that these stripes produce ... would appear
    as though there were concentric rings, tunnels or spirals in the
    world outside. So it seems that the tunnel is a natural consequence
    of the way in which the visual cortex represents the visual world.
    And the light at the end?  Because the number of neurons devoted
    to any unit area is much higher in the center of the visual field,
    you would expect a much greater effect in the centre if all neurons
    were equally affected by the release from inhibition. Presumably
    the more disturbed the system, the bigger the light ought to be,
    although no one has yet tested this idea.
    
    ... So the near-death experience may, after all, be not so mysterious.
     [The brain's] components can be seen as changes in mental models
    brought about by the disinhibition of the cortex and the breakdown
    of the normal model of reality driven by sensory input.
                
    [APPROPRIATE FOR FRIDAY THE 13th]

    
    Wow, this is extremely close to the recent article in "New Age
    Journal", complete with the Sagan theory.  I'll try to remember
    to take a look and see if there is any connection between the two
    articles (same sources, etc.).
    
    Cindy

    Thanks for typing in the summary.  I'd thought about doing it but
    was too lazy.
    
    Although there are a few details I would argue with, it was all
    in all quite a good article (specifically, I think Dr. Blackmore's
    association of consciousness with "most stable reality" misses
    the mark a bit, but, so far, I haven't been able to convince her
    of that.  In any case, I think that its close enough to accurate
    to not significantly invalidate her basic point).
    
    						Topher

    
    I checked the "New Age" article, and there appears to be no connection
    between the two.
    
    The authors of the NA article are Raymond A. Moody,Jr.,M.D. (author
    of 'Life After Life' and 'Reflections on Life After Life') and
    Paul Perry (executive director of 'American Health' magazine). 
    
    In the article, Carl Sagan's points made about the connection between
    the Near Death Experience (NDE's), particularly the 'tunnel experience'
    and the birth experience (the common experience shared by all humans) 
    as written about in his book entitled "Broca's Brain: Reflections on 
    the Romance of Science" are refuted by Carl Becker, Ph.D., and Dr.
    Becker ends his list with the conclusion that: "Babies don't remember 
    being born and don't have the faculties to retain the experience in 
    the brain." 
                             
    Cindy