Structural contributions to short-term synaptic plasticity.

Synaptic ultrastructure is critical to many basic hypotheses about synaptic transmission. Various aspects of synaptic ultrastructure have also been implicated in the mechanisms of short-term plasticity. These forms of plasticity can greatly affect synaptic strength during ongoing activity. We review the evidence for how synaptic ultrastructure may contribute to facilitation, depletion, saturation, and desensitization.