090625 Schreiber

The Bernstein Center Freiburg

Bernstein Seminar

Susanne Schreiber

Institut für Theoretische Biologie
Humboldt-Universität zu Berlin
Berlin, Germany

Mechanisms of reliable spike timing in response to rhythmic stimuli

Abstract:
Despite the presence of noise, the timing of spikes can be remarkably reliable and precise. In previous studies, reliability has been shown to depend strongly on the stimulus frequency. The value of the optimal input frequency has been explained in terms of two different neuronal phenomena: subthreshold membrane potential oscillations, on the one hand, and a resonance with the cell's firing rate, on the other hand.

Although these interpretations are fundamentally different from one another, we show here that the phenomena are not in conflict with one other, because they correspond to distinct firing regimes. On the basis of conductance-based neuronal models we discuss the mean-driven firing regime, where the stimulus mean is sufficient to elicit continuous firing, and the fluctuation-driven regime, where transient stimulus elevations are needed to generate spikes. The two regimes are characterized by distinct "symptoms" of unreliability - reduced spike precision and reduced spike probability - when the stimulus frequency does not match an optimal frequency. In addition, in the fluctuation-driven regime, best reliability may be achieved at intermediate noise levels, where spike probability is boosted and precision is not yet significantly impaired.

Host: Dr. Clemens Boucsein