Neuron charging

Matt Jones jonesmat at
Wed Aug 28 13:37:57 EST 1996

In article <32239C12.4F0A at> Gary Frank, garyfrank at writes:
>met.  I wonder if the post synaptic neurons that receive these impulses 
>are "charged up" as a result.  In other words, if a neuron doesn't 

Yes, in a manner of speaking. The neuronal membrane holds a charge for a
few milliseconds (depending on the type of neuron, and what the various
membrane conductances are) exactly like a capacitor. So a neuron is
closer to threshold (i.e., more likely to fire) for a brief time after
the last subthreshold depolarization. There's also a period _after_ it
fires when it's much less excitable (refractory period), for a completely
different reason. These ideas are covered in any good neurobiology text. 

>As I understand it, neurons fire at 
>increasingly high rates as the conditions they were designed for are 

This idea about "the conditions they were designed for" can be misleading
if you think about it on the level of an individual neuron. It's probably
more accurate to say that a particular neural "circuit" was designed
(evolved) to respond to certain conditions, and that this response is
made up of the firing patterns of the neurons within it. You might want
to look at some recent postings in the "Weighting of synaptic responses
thread", too.


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