Fig 7. Predictions of the dependence of triplet rules upon numbers of pairings.

(a) Synaptic strength modification (numerical simulations) as a function of the number of pairings for different triplets protocols. Each square represents the change in synaptic strength (which intensity is color coded) as a function of the number of pairings, for a precise Δt₁ and Δt₂. Insets (right) provide an alternative representation of the same quantity in the monophasic D (up), biphasic PD (middle) and triphasic PPD (down) case. (b) Schematic representation of the different triplets configurations in (a) with Δt_i = t_post − t_pre,i for pre-post-pre stimulations and Δt_i = t_post,i − t_pre for post-pre-post stimulations. (c) Different phases (mono-, bi- and triphasic) of STDP observed in protocols of triplets as a function of Δt₁ and Δt₂. P and D code for potentiation (LTP) and depression (LTD).