I thought this might be of interest to those who see some relationship between physics and psychology, over and above physiology.
It's interesting that where physics seems to end, psychology often times begins to appear!
Model Obtains Evidence Of Chaos In Brain's Neocortex
The neocortex is the most complex brain structure specific to humans and other
mammals. Now, evidence of chaos in the neocortex has been obtained in a
model by researchers at Swinburne University of Technology in Australia.
Chaos in the brain would manifest itself as unpredictable and seemingly random
electrical activity in a population of nerve cells, or neurons.
Chaos may have an important neurological function: researchers have
speculated that it could provide a flexible and rapid means for the brain to
discriminate between different sounds, odors and other perceptual stimuli.
Electroencephalograms (EEGs) record electrical activity in the cerebral cortex,
but they, and all other current experimental techniques, may never be able to
detect clear and unequivocal signs of chaos, since the cortex also emits a large
amount of obscuring "noise," or random electrical activity.
Using realistic representations of brain physiology, many researchers are trying
to devise models that reproduce the output of EEGs and also offer new insights
into the brain's inner workings. But previous models either do not allow for chaos
to appear or have been unable to demonstrate that chaos can occur under the
conditions imposed by the structure of the brain.
In the present work, the researchers model the behavior of two large populations
of neurons: excitatory (which bring other neurons closer to firing) and inhibitory
(which make it more difficult for other neurons to fire).
Specifically, they look at the "mean soma membrane potential," the electric
potential between the outside and inside of the neuron's cell body (higher
potential means more frequent firing).
Varying the rate of external electrical impulses to each neuron population, they
found the mean electrical activity was irregular and noise-like (it looked like noise
but really wasn't) for a wide range of external inputs.
Quantitatively, such behavior is associated with a positive Lyapunov exponent, a
hallmark of chaos. (A Russian mathematician who died in 1918, Aleksandr
Lyapunov devised important methods of approximation.)
The existence of chaos, the researchers say, would provide a means for the
brain to change its response rapidly to even slightly different stimuli. (Dafilis et
al., Chaos, September 2001; text available at this URL.)
(Editor's Note: This story is based on PHYSICS NEWS UPDATE, The
American Institute of Physics Bulletin of Physics News Number 551 August 8,
2001 by Phillip F. Schewe, Ben Stein, and James Riordon.)
[Contact: David Liley]
20-Aug-2001
Mike Lee, MA
P435A Duff Roblin Building
(204) 474-6627 (office)
Dept of Psychology
University of Manitoba
Winnipeg, MB Canada
[EMAIL PROTECTED], http://home.cc.umanitoba.ca/~mdlee, http://home.cc.umanitoba.ca/~mdlee/Teaching.html
Owner: Talk-Psychology Mailing List for Students of Introductory Psychology
Max Planck, one of the great founders of Quantum Physics:
"...I regard consciousness as fundamental. I regard matter as derivative from consciousness.
We cannot get behind consciousness. Everything that we talk about,
everything that we regard as existing, postulates consciousness."
The Observer, London, January 25, 1931
English mathematician and astronomer Sir Arthur Eddington declared,
"the stuff of the world is mind-stuff" and wrote:
"All through the physical world runs that unknown content, which must surely be
the stuff of our consciousness. Here is a hint of aspects deep within the world of physics, and yet unattainable by the methods of physics. And, moreover, we have found that
where science has progressed the farthest, the mind has but regained from nature
that which the mind has put into nature."
A.S. Eddington, Space, Time and Gravitation: An Outline of the General
Relativity Theory (1920; reprint, New York: Harper & Row, 1959), 200-201.
