We assume that postsynaptic spiking is generated by a Poisson process with a rate determined by a baseline firing rate, the recent history of the neuron’s firing, as well as input produced by presynaptic spikes (see Methods for details).

While these models can describe the auto and cross-correlations present in the data, neurons often have more complex nonlinear behavior [56,57] and generate spikes much more reliably than Poisson processes [58].

This corresponds to a neuron firing at a rate of 5Hz with more regularity (CV % 0.7) than a Poisson process .

F) Dependence of the log likelihood ratios of models M1 and M2 relative to a homogeneous Poisson process on the length of data used for analysis.