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From: donham@pender.ee.upenn.edu (Christopher Donham)
Newsgroups: comp.ai.neural-nets
Subject: How many neurons in a ...
Message-ID: <32993@netnews.upenn.edu>
Date: 16 Nov 90 00:02:08 GMT
Sender: news@netnews.upenn.edu
Reply-To: donham@pender.ee.upenn.edu (Christopher Donham)
Organization: University of Pennsylvania
Lines: 51



One of the questions that often comes up when discussing electronic 
implementations of neural networks is the type of biological system that
contains a given number of neurons.  The usefullness of such a comparison
is highly questionable due to the very different nature of the systems. 
None-the-less I would be interested in obtaining information about
the number of neurons in various organisms/animals.  Specifically, I
would like to find a source that will fill in the following chart:

      Number of neurons*     |    Organism
--------------------------------------------------
             ~1              |
             ~10             |
             ~100            |
             ~1000           |
             ~10^4           |
             ~10^5           |
             ~10^6           |
             ~10^7           |
             ~10^8           |
             ~10^9           |
             ~10^10          |    Man.

*extremely approximate, obviously

I would be most interested in a source I can quote (book, journal
article, etc), though if you know any of the numbers, I would still
like to hear from you even if you cannot give an "authoritative"
source.  I have checked several neuroanatomy and comparative
neuroanatomy texts, as well as a couple of physiological psychology
texts, and was very surprised that I could not find the above
information (the texts described lots of creatures, but would not give
estimates of the total number of neurons).

I do not normally read this group, so please send all replies to
me directly.  Please, no messages telling me how silly/wrong it is to
compare the electronic and biological systems in this manner.  I know
that the electronic system is very different then the biological system.

Thanks for any information.

Chris

Christopher Donham     University of Pennsylvania    donham@axon.ee.upenn.edu
 Department of EE          200 South 33rd. St.                              
 VLSI Grad. Stud.        Philadelphia, PA 19104          (215) 898-7116      
-------------------------------------------------------------------------------
| Christopher Donham                            University of Pennsylvania    |
| Electrical Engineering                        200 South 33rd St.            |
| donham@grip.cis.upenn.edu                     Philadelphia, PA 19104        |