Fig. 1.

The triplet STDP rule. (A) Synaptic depression is induced as in classical pair-based STDP using spike pairs separated by Δt₁ = t^post − t^pre < 0. Synaptic potentiation is induced using triplets of spikes consisting of two postsynaptic spikes and one presynaptic spike on the basis of the timing interval between them Δt₁ = t^post − t^pre > 0 and Δt₂ = t^post − t′^post > 0. (B) Synaptic change as a function of the time between pre- and postsynaptic spikes in a protocol where 60 pairs were presented at different frequencies ρ = 0.1, 20, and 50 Hz. Depression predominated at low frequency, whereas potentiation was more prevalent at high frequencies. The data points are experiments are from ref. 17 and the lines were generated with the triplet STDP rule with the parameters taken from ref. 15.