Holt, Gary R. and Koch, Christof (1997) Shunting inhibition does not have a divisive effect on firing rates. Neural Computation, 9 (5). pp. 1001-1013. ISSN 0899-7667. http://resolver.caltech.edu/CaltechAUTHORS:HOLnc97
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Shunting inhibition, a conductance increase with a reversal potential close to the resting potential of the cell, has been shown to have a divisive effect on subthreshold excitatory postsynaptic potential amplitudes. It has therefore been assumed to have the same divisive effect on firing rates. We show that shunting inhibition actually has a subtractive effecton the firing rate in most circumstances. Averaged over several interspike intervals, the spiking mechanism effectively clamps the somatic membrane potential to a value significantly above the resting potential, so that the current through the shunting conductance is approximately independent of the firing rate. This leads to a subtractive rather than a divisive effect. In addition, at distal synapses, shunting inhibition will also have an approximately subtractive effect if the excitatory conductance is not small compared to the inhibitory conductance. Therefore regulating a cell's passive membrane conductance—for instance, via massive feedback—is not an adequate mechanism for normalizing or scaling its output.
|Additional Information:||© 1997 Massachusetts Institute of Technology. Posted Online March 13, 2006. We thank the referees for helpful critical comments on this article. This research was supported by the NIMH and the Sloan Center for Theoretical Neuroscience. The compartmental models and associated programs are available from: ftp://ftp.klab.caltech.edu/pub/holt/holt_and_koch_1997_normalization.tar.gz|
|Group:||Koch Laboratory, KLAB|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||25 Jun 2009 16:51|
|Last Modified:||23 Sep 2013 18:58|
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