Abstract:

Synchronization in feed-forward neuronal subnetworks in the brain has been proposed to explain precisely timed spike patterns observed in experiments. While the attractor dynamics of the network is now well understood, the single neuron mechanisms remained unexplained. Previous attempts have captured the effects of the highly fluctuating membrane potential by relating spike intensity f(U) to the instantaneous voltage U of the input. We demonstrate that spike probability is high during the rise and low during the decay of U(t) exhibiting the d/dt U-dependence of f, not refractoriness, as the essential mechanism of synchronization. Moreover, the bifurcation scenario is quantitatively described by a simple f(U, d/dt U) relationship. The findings suggest f(U, d/dt U) as the relevant model class for the investigation of neural synchronization phenomena in a noisy environment.