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From: wcalvin@milton.u.washington.edu (William Calvin)
Newsgroups: comp.ai
Subject: Re: The bandwidth limitation (was: Re: How much info can the brain hold?)
Message-ID: <12118@milton.u.washington.edu>
Date: 2 Dec 90 07:38:01 GMT
References: <3415@bruce.cs.monash.OZ.AU> <7988@uwm.edu> <4208@media-lab.MEDIA.MIT.EDU>
Organization: University of Washington, Seattle
Lines: 13

My standard refrain about the numbers game (for neurons in the
brain), back when I wrote THE THROWING MADONNA, was "that of those
famous 10 billion neurons comprising the brain, 100 billion of them
are located in just one section of the brain (the granule cell
neurons of the cerebellum)."  The number 10 billion was the 1968
estimate of the numbers of neurons in cerebral cortex (which is not
exactly all of the brain) of one hemisphere (so 20 billion in both). 
More recent estimates more than doubled that.  But estimating whole
brain is still a very dicey business, even for order-of-magnitude.
	The number of synapses per neuron is somewhere between 1E3
and 1E5, and depends on neuron size.

                  William H. Calvin             wcalvin@u.washington.edu


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