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WORKSHOP ON:
CENTRAL PROBLEMS IN SINGLE CELL COMPUTATION
16-18 September 2002
By invitation only
Venue
B10 Seminar Room, Alexandra House, 17 Queen Square, London, WC1N 3AR
| Spike frequency adaptation
and neocortical rhythms |
| Misha Tsodyks,
Department of Neurobiology, Weizmann Institute, Israel |
| Spike-frequency adaptation in
neocortical pyramidal neurons was examined using the whole cell patch-clamp technique and
a phenomenological model of neuronal activity. Noisy current was injected to reproduce the
irregular firing typically observed under in vivo conditions. The response was quantified
by computing the poststimulus histogram (PSTH). To simulate the spiking activity of a
pyramidal neuron, we considered an integrate-and-fire model to which an adaptation current
was added. A simplified model for the mean firing rate of an adapting neuron under noisy
conditions is also presented. The mean firing rate model provides a good fit to both
experimental and simulation PSTHs and may therefore be used to study the response
characteristics of adapting neurons to various input currents. The models enable
identification of the relevant parameters of adaptation that determine the shape of the
PSTH and allow the computation of the response to any change in injected current. The
results suggest that spike frequency adaptation determines a preferred frequency of
stimulation for which the phase delay of a neuron's activity relative to an oscillatory
input is zero. Simulations show that the preferred frequency of single neurons
dictates the frequency of emergent population rhythms in large networks of adapting
neurons. Adaptation could therefore be one of the crucial factors in setting the frequency
of population rhythms in the neocortex. |
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