We only use 5% of our brain, etc..

John M. Price ez001932 at othello.ucdavis.edu
Tue Jan 25 14:41:39 EST 1994


Bill Skaggs (bill at nsma.arizona.edu) wrote:
: kspencer at iti.org (Kevin Spencer) writes:

:    Why do people insist upon comparing the brain, an extremely complex
:    dynamical system, to digital computers?  Neurons are *not* transistors.
:    The cortex is *not* a circuit board.  The "memory" of a brain is *not*
:    the same thing as computer "memory".

: I don't think it's useful to view the brain as a digital computer, but
: I *do* think it's useful to view it as a digital information
: processing device, sending discrete pulses from place to place and
: integrating them.  The concepts of bandwidth and memory capacity make

This is only in the transmission of information.  If you look at a
synapse, the communication reverts to analog - the quantity of transmitter
released.  Further, this analog 'image' in millivolts across the soma's
membrane, at the hillock, is that which makes the decision to fire that 
particular cell.  Even further, the integration of signals at the soma is 
analog.

Perhaps the idea of BCD is appropriate for the analogy.  The digital
action potentials are very efficient at transmitting the data long
distances, but, as animals, the result becomes, at the end of the wire, an
analog form of information.  In many ways, the brain is essentially a
collection of hormone delivering machines - albeit with highly restricted
targets - with the adaption of action potentials for insuring that the
information gets to the target cells.  This perhaps can be seen in the
PNS.  The sympathetic system has, as does the parasympathetic, a two
neuron link to the target tissue.  The exception is the adrenal gland. 
Might the adrenal gland BE the second neuron?  with a target of the entire
body? 



--
____________________________________________________________________________
John M. Price, Ph.C.(ABD)| Physiological Emphasis - Likes machines too!
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