Axon collaterals ?

Joe Legris jalegris at xympatico.ca
Wed Dec 17 20:55:39 EST 2003


nettron2000 at aol.com wrote:
> Joe Legris <jalegris at xympatico.ca> wrote in message news:<3FDFBB23.6060108 at xympatico.ca>...
> 
>>Matthew Kirkcaldie wrote:
>>
>>>In article <Xns94539459E651FBilZ0rhotmailcom at 202.20.93.13>,
>>> BilZ0r <BilZ0r at TAKETHISOUThotmail.com> wrote:
>>>
>>>
>>>
>>>>Yes, its very common. Just often another way a cell mediates negative 
>>>>feedback.
>>>
>>>
>>>Why would an autapse from an excitatory neuron constitute "negative 
>>>feedback"?  It would be a positive feedback loop if anything.
>>>
>>>         Matthew.
>>
>>Positive feedback might make a neuron "bursty" - so that any time it 
>>fires, there's a good chance it will fire many times in rapid 
>>succession. Maybe the length of the feedback loop sets the bursting speed.
> 
> 
>  Bursting speed ? I was under the assumption that a typical neuron
> operated at its max "frequency" when bursting. If this isnt
> necessarily the case, then what could be the alleged purpose of
> bursting in neural computation ?

I don't know if there are various bursting speeds, I was only guessing.

Now that I think about it a little more, positive feedback would have 
the effect of making the neuron progressively more active, so that its 
firing rate would increase at a rate proportional to its present firing 
rate. An exponential function?

-- 
Joe Legris




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