Habituation and Conditioning

Harry Erwin erwin at trwacs.fp.trw.com
Tue Nov 23 13:19:34 EST 1993


In article <1993Nov22.175721.3655 at antioch.edu> jerwin at antioch.edu writes:
>
>In article <1993Nov21.080451.56374 at gmuvax>, cs103_03 at gmuvax writes:> 
>> Actually, I've seen a couple of theories on this. 
>> The books are at the office,
>> but Dowling proposes the Ca++ depletion theory. The problem is that habituation
>> is supposed to be a reaction to a lack of response on the postsynaptic side.
>> That requires either a messenger or a difference in the chemical environment
>> (i.e., Ca++ depletion and non-replenishment). I'm beginning to suspect that
>> all synapses habituate in the short-term, and short-term potentiation increases
>> the sensitivity of the post-synaptic side enough to overcome the 
>> habituation.

>Is this related to the calpain-calcium theory of memory, in which calcium
>can stimulate fodrin degradation and thus change the "architecture" or
>"shape" of the post synaptic areas?
>I don't have the article, but it was written by Lynch and Baudry, titled
>"The Biochemistry of Memory: A New and Specific Hypothesis" and was 
>published in a 1984 issue of Science.
>I am wondering if this work was expanded upon, or disproven as a general 
>hypothesis.

It's related, in that it assumes habituation has that mechanism. Look at
Bliss and Collingridge, 'A synaptic model of memory: long-term
potentiation in the hippocampus,' Nature, 361:31-39, 7 January 1993. My
concern, though, is with habituation, which appears to be a pre-synaptic
mechanism. In the olfactory bulb it is at least as important as
conditioning (stp and ltp). Given Freeman's paper two weeks ago at the
Washington conference, the mechanisms of learning and pattern matching
previously identified in the OB appear to be generic for all the sensory
modalities and cortical processing. That would mean we are finally homing
in on the 'mechanism' of the brain. Unfortunately, a key aspect of that
'mechanism' is how the functional modules of the brain are 'loaded' with
the patterns they use for their processing, and that is the problem I'm
wrestling with here.

Cheers,
-- 
Harry Erwin
Internet: herwin at cs.gmu.edu (not erwin at trwacs.fp.trw.com!)
Working on Freeman nets....



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