Dendritic sodium spikes endow neurons with inverse firing rate
response to correlated synaptic activity.
Tomasz Gorski, Romain Veltz, Mathieu Galtier, Helissande
Fragnaud, Bartosz Telenczuk and Alain Destexhe
Many neurons possess dendrites enriched with sodium channels and
are capable of generating action potentials. However, the role of
dendritic sodium spikes remain unclear. Here, we study
computational models of neurons to investigate the functional
effects of dendritic spikes. In agreement with previous studies, we
found that point neurons or neurons with passive dendrites increase
their somatic firing rate in response to the correlation of
synaptic bombardment for a wide range of input conditions, i.e.
input firing rates, synaptic conductances or refractory periods.
However, neurons with active dendrites show the opposite behavior:
for a wide range of conditions the firing rate decreases as a
function of correlation. We found this property in three types of
models of dendritic excitability: a Hodgkin-Huxley model of
dendritic spikes, a model with integrate-and-fire dendrites, and a
discrete-state dendritic model. We conclude that neurons equipped
with with fast dendritic spikes confer much broader computational
properties to neurons, sometimes opposite to that of point neurons.
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