Single Citation Matcher
Batch Citation Matcher
Neuronal integration of synaptic input in the fluctuation-driven regime.
Kuhn A, Aertsen A, Rotter S.
Neurobiology and Biophysics, Institute of Biology III, Albert-Ludwigs-University, D-79104 Freiburg, Germany.
sensory stimulation, visual cortical neurons undergo massive synaptic
bombardment. This increases their input conductance, and action
potentials mainly result from membrane potential fluctuations. To
understand the response properties of neurons operating in this regime,
we studied a model neuron with synaptic inputs represented by transient
membrane conductance changes. We show that with a simultaneous increase
of excitation and inhibition, the firing rate first increases, reaches
a maximum, and then decreases at higher input rates. Comodulation of
excitation and inhibition, therefore, does not provide a
straightforward way of controlling the neuronal firing rate, in
contrast to coding mechanisms postulated previously. The synaptically
induced conductance increase plays a key role in this effect: it
decreases firing rate by shunting membrane potential fluctuations, and
increases it by reducing the membrane time constant, allowing for
faster membrane potential transients. These findings do not depend on
details of the model and, hence, are relevant to cells of other
cortical areas as well.
PMID: 15014109 [PubMed - indexed for MEDLINE]