How ionic conductances help to shape temporal firing characteristics

Abstract:

Although for bare spike generation only very few ionic conductances would be needed, neurons can express a large variety of ion channels with diverse properties. It is straightforward to assume that the conductances play an important role in shaping neural responses. Here, we present mechanisms by which ionic conductances can influence two temporal characteristics of the spike code: spike-timing reliability and specific firing patterns. In the first case, a cellʼs ion channel composition determines how spike-timing precision depends on the input frequency. In addition, ionic conductances can also modify the extent to which noise affects spike-timing precision. In the second case, a resonance in the subthreshold membrane potential - which is known to result from specific ionic conductances with slow dynamics - leads to clustered firing patterns. To fully account for the observed clustered patterns in stellate cells of the entorhinal cortex, however, also spike-induced currents have to be considered.