question: job of a neuron

Richard Norman rsnorman at mediaone.net
Mon Sep 3 10:21:42 EST 2001


On Mon, 03 Sep 2001 11:06:32 -0400, Kalman Rubinson <kr4 at nyu.edu>
wrote:

>On Mon, 03 Sep 2001 01:31:01 GMT, "Mark Zarella"
><markzarella at mediaone.net> wrote:
>
>>Perhaps the easiest way of descibing its job rather than the "how" part is
>>to say that it simply transmits and transduces signals.  Your question seems
>>to me to be akin to asking "what is the job of a copper wire in a XYZ
>>circuit?"  The answer depends on that particular copper wire's relation to
>>the other components.
>
>But we already get into problems when you say it 'transduces' signals.
>While most neurons do transduce signals by converting chemical energy
>into an electrical signal, transduction, per se, is not a defining
>property since the synapses can be electrical. A neurons sums,
>temporally and spatially, all the signals impinging on it and fires an
>output signal or signals depending on the inputs and the membrane
>properties of the neuron.  It can function as a gating unit, a
>computing unit, a time-keeper and many other roles.
>
>The original query suggested that the poster wanted a simplistic
>definition and, as you say, that's equivalent to asking the function
>of a particular wire, or any other generic component, in a complex
>circuit.

As you say, a synapse can be electrical.  By the same token, a neuron
does NOT have to "fire".  There are many neurons that function
perfectly well without being able to produce action potentials. That
is why I simply referred to the membrane potential as being the
information carrier.  The release of synaptic transmitter (or the
functioning of an electrical synapse) works perfectly well with graded
membrane potentials.

The notion of cell machinery and mechanisms is being transformed by
the more complete understanding and appreciation of the role of "cell
signaling".  In this context, the function of the neuron is best
understood is an extreme specialization of the cell signaling
machinery.  Neurons do not really do anything that other cells don't
also do.  They just do it to extremes.


>




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