The recoding of input into output spike patterns in PCs is thought to depend on how long-term synaptic plasticity modifies PC synaptic responsiveness. While classical pf-PC LTD has postsynaptic expression and simply causes a scale-down of postsynaptic currents, a presynaptic change in release probability (P) would modify neurotransmission dynamics (Tsodyks and Markram, 1997; Nieus et al., 2006). These can shift from the typical short-term facilitation at low P to short-term depression at high P. These changes can therefore differentially affect the PC BPR.