Figure 2.

Transfer function of I&F neurons driven by background white noise Equation (5). We measure the firing rate of the neuron as a function of a constant current injection to estimate ρ(u₀), where for constant I_inj, u₀ = I_inj/g_L. (Top) The transfer function of noisy I&F neurons in the absence of refractory period [ρ(u) = r(u), circles]. We observe that ρ is approximately exponential over a wide range of inputs, and therefore compatible with neural sampling. Crosses show the transfer curve of neurons implementing the abstract neuron Equation (1), exactly. (Bottom) With an absolute refractory period the transfer function approximates the sigmoid function. The firing rate saturates at [250]Hz due to the refractory period chosen for the neuron.