Figure 6.

Simple model to study the effects of synchronization on the reliability of the neuronal responses. Seventy-five neurons synapse on a unique neuron modeled as a leaky integrate-and-fire as in Eq. 1, with the addition of a refractory period; g = 0.005/s, σ = 0.07, refractory period = 10 ms. Mean rate (□) and reliability (○) are shown for a neuron integrating spikes over an input layer of 75 neurons. A pattern of spikes was randomly generated (3.75 Hz), and each neuron of the input layer feeds the same pattern of spikes with a delay δ. The values of the other parameters are as in Fig. 5. When the input layer is synchronized, V̇ of the integrating neuron is big and the response is very reliable. In this case, part of the charge from the input layer is lost because there is no summation during the refractory period. When δ increases, the reliability decreases but the mean firing rate is increased. This result suggests that a function of synchronization, which is known to occur in many different neuronal networks, might be to increase the reliability on the system at the expense of the intensity of the signal.