brain plasticity - what causes it?
jonesmat at ohsu.edu
Sun Nov 7 14:59:41 EST 1999
In article <38243B60.F9787ABC at unf.edu> John E Anderson, jander at unf.edu
>various sorts. Some of these things must be responsible for inducing
>plasticity -- rearrangements in the surrounding brain tissue. My
>question is do *all* neurons produce whatever it is that induces
>plasticity, or only some?
Taking your definition of "plasticity" (i.e., rearrangements in the
surrounding tissue), I would guess that all neurons can cause this,
regardless of what neurotransmitter they secrete. I say that because
essentially every -postsynaptic- receptor known is subject to regulation
of its density and expression on the postsynaptic membrane in a manner
that depends on its frequency of exposure to the neurotransmitter to
which it responds. That is, chronic exposure (or prevention of exposure)
to acetylcholine, say, will cause postsynaptic cells to either up- or
downregulate the density of ACh receptors they express, or sometimes
which ACh receptor subunits are expressed, and also the location in which
these receptors are expressed. The same holds true for glutamate, GABA,
serotonin, dopamine, etc. So it appears that, because postsynaptic
receptors are regulated by exposure to the neurotransmitter, every neuron
that secretes any neurotransmitter must also have some role in guiding
"rearangements" in the surrounding tissue.
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