Mapping from the spike domain to the rate-based domain

The dependence of synaptic plasticity on both presynaptic activity and postsynaptic activity, as postulated by Hebb, has been clearly and repeatedly demonstrated in the laboratory. Traditionally, "activity" has been measured by counting spikes in a short time window to get an average firing rate. Recent experiments reveal functional synaptic changes that depend on the precise timing of individual pairs of spikes (one presynaptic and one postsynaptic). Here, the emergence of rate-based learning rules from spike-based dependencies is introduced, through the idea of a rate map in synaptic weight space.