Fig 3. Cortico-striatal STDP and its dependence with pairing number.
(a) Change in macroscopic synaptic strength as a function of the number of pairings Npairings and spike timing Δt computed with the analytical formula derived in the Methods section shows a non-monotonic LTP induction for Δt < 0 and monotonic LTD establishment of Δt > 0. The respective role of eCB and NMDAR pathways is investigated in Fig 5(b)–5(d) Sample STDP profiles for 13 (b), 40 (c) and 100 (d) pairings (top), with calcium traces associated with Δt = −10 ms (left) and Δt = +10 ms (right). Analytical solution (Eqs (16) and (17), brown line) and numerical simulations of Eq (6) (blue crosses) are both represented for comparison.