Re: Antidromic Conduction

[Tim Shearon]

Steven is basically correct (well, as usual he IS correct):

>The traditional view is that antidromic conduction is an evolutionary
>adaptation that exists merely to help neurophysiologists out. That is,
>nature intended neuronal conduction to proceed from dendrite to axon
>terminal only, and it's a happy accident that it can also go the other
>way, at least until it encounters a synapse.

But, I find this a bit disturbing when presenting it to students (not Stephen's statement but the way we present it, especially textbooks). It may well do the same on the list. We don't _really_ think this way; it is metaphorical. We don't mean that "nature intended" but that may be what students hear (i.e., taking it literally). So I'm just a bit reluctant (paranoid?) about saying things that fall neatly into magical belief systems (especially in light of all the recent discussions on magical thinking). I don't think there really is a _reason_ why antidromal conduction occurs (what Stephen means by "to help out neurophysiologists) beyond the physical explanation of what antidromal conduction is. But there is no real reason for it not to except for the cases in which the system has evolved means to stop it. E.g., with it occurring without checks, the axon hillock and neuromodulators, autoreceptors, etc.) and stops we would all be epileptic (speculative!). However, this points out that, in a weird way, there is reasoned (metaphor again) antidromal conduction of information by autoreceptors, etc. I'm just a bit cautious about any explanations invoking a reason beyond (as Stephen so aptly put it) it just happens that way.
Tim S. _______________________________________________________
Timothy O. Shearon, PhD
Albertson College of Idaho
Department of Psychology
2112 Cleveland Blvd
Caldwell, Idaho

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