Somato-dendritic interactions underlying action potential generation in
neocortical pyramidal cells in vivo
Alain Destexhe, Erik Lang and Denis Paré
In: Computational Neuroscience. Trends in Research (edited by J.
Bower), Plenum Press, New York, pp. 167-172, 1998
Abstract
By combining computational models with intracellular recordings of neocortical
pyramidal cells in vivo, we provided a plausible explanation for our
experimental observations on how action potential are controlled by IPSPs in
these cells. Models and experiments suggest that IPSPs affect action
potentials by two mechanisms: a shunt effect due to the opening of ion
channels underlying the IPSPs, and a voltage-dependent effect by preventing
dendritic Na+ channels to participate to the somatic spike. Further, we
suggest that under conditions of synaptic activity that occurs during active
states in vivo, the conductance shunt and the voltage-dependent effect of
synaptic inputs do not provide favorable conditions for backpropagating action
potentials.
Movies
Several movie files illustrate the dynamics of membrane potential in soma and
dendrites in a simulated neocortical layer V pyramidal neuron. They are an
excellent complement to the figures of the paper. The somatodendritic
distribution of membrane potential is shown by colors in three cases of action
potential generation:
backp_control.mpg Back-propagating action potential following current
injection in the soma
backp_stim_dist.mpg Forward-propagating action potential following
"distal" stimulation
backp_stim_prox.mpg Action potential following stimulation of "proximal"
synapses. In this case, there is no action potential invasion in dendrites
and the amplitude of the somatic spike is reduced (see paper)
See also the related article: Paré D, Lang EJ
and Destexhe A. Inhibitory control of somatic and dendritic sodium spikes in
neocortical pyramidal neurons in vivo: an intracellular and computational
study. Neuroscience 84: 377-402, 1998.
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