TITLE

Sharpness of Spike Initiation in Neurons Explained by Compartmentalization

AUTHOR(S)
Brette, Romain
PUB. DATE
December 2013
SOURCE
PLoS Computational Biology;Dec2013, Vol. 9 Issue 12, p1
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
In cortical neurons, spikes are initiated in the axon initial segment. Seen at the soma, they appear surprisingly sharp. A standard explanation is that the current coming from the axon becomes sharp as the spike is actively backpropagated to the soma. However, sharp initiation of spikes is also seen in the input–output properties of neurons, and not only in the somatic shape of spikes; for example, cortical neurons can transmit high frequency signals. An alternative hypothesis is that Na channels cooperate, but it is not currently supported by direct experimental evidence. I propose a simple explanation based on the compartmentalization of spike initiation. When Na channels are placed in the axon, the soma acts as a current sink for the Na current. I show that there is a critical distance to the soma above which an instability occurs, so that Na channels open abruptly rather than gradually as a function of somatic voltage.
ACCESSION #
93395134

 

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