Effective STDP learning windows that show the synaptic change, ΔK, caused by a spike pair with the timing difference, Δt, between the pre- and post-synaptic spikes. The different windows are for different reward signal levels (y = 0, 1, 2, 3, 4, 5, and 6, shown in green, blue, purple, magenta, red, orange, and yellow lines, respectively). A: Classical RSTDP has no LTD or LTP when there is no reward and increasing amounts of both as reward increases. B: Generalized RSTDP allows separate modulation of LTP and LTD and non-zero LTP and LTD when there is no reward. Shown here is generalized RSTDP parameterized to match the effect dopamine has been observed to have on STDP . Switching of LTD to LTP for high reward values is exhibited.
Kerr et al. BMC Neuroscience 2013 14(Suppl 1):P48 doi:10.1186/1471-2202-14-S1-P48