spreading of action potentials

Harry Erwin herwin at vanish
Sat Oct 15 20:56:48 EST 1994


Kevin N Gurney (hssrkng at brunel.ac.uk) wrote:
: I am *not* a neuroscientist so I apologise if my questions appears
: naieve.

: I have recently started to investigate the dynamics of action-potential
: production and have used the 'Neurokit' script-set in the Genesis
: simulator to help my understanding. The most significant thing I
: noticed was that the action potential, as well as propagating along the
: axon, also propagates over the soma and dendritic tree. In the latter
: case I presume this is done electrotonically. There appears to be no
: mention of this kind of propagation in the usual text - One gets the
: idea that action potential spikes propagate along axons alone.

: My first question is: 
: Is this behaviour an artifact of the simulator or is it `real'?

It's very real. In the pyramidal cell, this process 'ignites' the apical
dendrite if it is sufficiently stimulated, and also fires the basal
dendrites (but apparently not the apical dendrite) when the cell
'spikes.' In neurons without axons (probably the vast majority), this
is the normal process. 

: Since neural membranes are continuous I suspect that it is veridical.

: If so, then does not the altered membrane potential on dendrites (due
: to spiking at the axon hillock) affect the production of PSPs on
: transmitter binding?

You bet! The engineering model of the neuron is biologically unreal. The
data processing within the biological neuron is extensive and quite
sophisticated.

: thanks

: ------------------------------------------------------------
: Kevin Gurney
: Dept. Human Sciences, Brunel University, Uxbridge, Middx., UK

: Tel: 	0895 274000 X2770 (or 2742).        Fax: 0895  237573
: email:	Kevin.Gurney at brunel.ac.uk
: WWW home page:  http://www2.brunel.ac.uk:8080/~hssrkng/
: ------------------------------------------------------------


--
Harry Erwin
Internet: herwin at gmu.edu 
Just a dumb graduate student working on Katchalsky network models....
(And if you believe that, I have a ranch in California to sell you.)



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