Facilitation, augmentation and potentiation at central synapses

Release probability (P) appears to be a major factor that influences the pa ttern of transmitter release. At cortical pyramidal axon inputs onto differ ent classes of target cells, very different release patterns are observed, patterns that correlate with release probability, Simplistically, 'low P' s ynapses display facilitation and augmentation, whereas 'high P' synapses su pplied by the same axon exhibit paired-pulse and frequency-dependent depres sion. Different combinations of factors probably contribute to release prob ability at different terminals, during development and under different expe rimental conditions. The recent advances made by molecular biological studi es of the release machinery do, however, provide candidate proteins and pro tein-protein interactions whose differential distributions might be importa nt factors in determining the patterns of transmitter release.