Sensory perception (neurobiology query)

Hannah Dvorak-Carbone hdvorak at cns.caltech.edu
Fri Aug 21 11:46:22 EST 1998


In article <35DC306F.5BF9 at no.spam.thanks.oitunix.oit.umass.edu>, 
edh at no.spam.thanks.oitunix.oit.umass.edu says...
>
>K C Cheng wrote:
>> Re the 1st: action potentials are surely transmitted along dendrites as
>> well. Lots of literature on this. Sorry, I'm too busy etc. right now to
>> find and quote them for you.   But try the huge American Physiological
>> Society Handbook, volumes on neurons.
>
>I think you're confusing action potentials with postsynaptic
>potentials.  [rest - accurate but incomplete - snipped]

Action potentials, while usually initiated in the soma or the initial segment 
of the axon, can propagate up into the dendrites, thanks to the 
voltage-dependent sodium channels found there.

See: Johnston, D., Magee, J.C., Colbert, C.M., and Christie, B.R. Active 
properties of neuronal dendrites. Annu. Rev. Neurosci. 19:165-186, 1996, 
for a good review of the active properties of dendrites.  

Examples of the possible role of back-propagating action potentials in synaptic 
plasticity are:

Magee, J.C., and Johnston, D. A synaptically controlled, associative signal for 
Hebbian plasticity in hippocampal neurons. Science 275:209-213, 1997,  and

Markram, H., Lubke, J., Frotscher, M., and Sakmann, B. Regulation of synaptic 
efficacy by coincidence of postsynaptic APs and EPSPs. Science 275:213-215, 
1997.

(Please do not take the use of the term "back-propagating" to mean that this 
mechanism could be used to implement back-propagation learning algorithms in 
artificial neural networks.  This is something different.)

- Hannah Dvorak-Carbone




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