Impact of network activity on noise delayed spiking for a Hodgkin-Huxley model

In a Hodgkin-Huxley neuron model driven just above threshold, external noise can increase both jitter and latency of the first spike, an effect called “noise delayed decay” (NDD). This phenomenon is important when considering how neuronal information is represented, thus by the precise timing of spikes or by their rate. We examine how NDD can be affected by network activity by varying the model's membrane time constant, τ<Subscript>m</Subscript>. We show that NDD is significant for small τ<Subscript>m</Subscript> or high network activity, and decreases for large τ<Subscript>m</Subscript>, or low network activity. Our results suggest that for inputs just above threshold, the activity of the network constrains the neuronal coding strategy due to, at least in part, the NDD effect. Copyright EDP Sciences/Società Italiana di Fisica/Springer-Verlag 2008