human vs machine

Joseph Strout jstrout at ucsd.edu
Fri Aug 11 12:06:13 EST 1995


It has been said (please excuse me for not quoting) that there is no 
experimental way to determine neural connections in a brain (or ganglion, 
or whatever).  How about going in and having a look?

All right, the posters must have meant no way with *today's* technology, 
but it sure sounded like they meant no way conceivable.  But I can 
conceive of deriving all the information needed to configure a model of a 
particular brain by serial reconstruction of thin series, for example.  
This technique is widely used (albiet on a much smaller scale) today.  
If, as some have suggested, long-term memories are stored by the presence 
and absence of synapses, then it should be a (theoretically) trivial 
matter to determine what those synapses are.  [In case I'm being obtuse, 
I'll illustrate with an example: freeze the brain very solid, cut it into 
millions of tiny slices, scan each one in an electron microscope for 
structural information, and put it all back together in the computer.]

Of course, it will probably turn out that neuron morphology alone is not 
enough to properly configure a detailed model; for example, you may need 
to know the concentration of Ca++ in various parts of the cell, or how 
much CaMKII is phosphorylated.  This would make things more difficult... 
but now we digress.

,------------------------------------------------------------------.
|    Joseph J. Strout           Department of Neuroscience, UCSD   |
|    jstrout at ucsd.edu           http://sdcc3.ucsd.edu/~jstrout/    |
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