A nanoscale resolution view on synaptic vesicle dynamics

The ability of synapses to sustain neurotransmitter release during continuous activity critically relies on an efficient vesicle recycling program. Despite extensive research on synaptic function, the basic mechanisms of vesicle recycling remain poorly understood due to the relative inaccessibility of central synapses to conventional recording techniques. The extremely small size of synaptic vesicles, nearly five times below the diffraction-limited resolution of conventional light microscopy, has hampered efforts to define the mechanisms controlling their cycling. The complex sequence of dynamic processes that occur within the nerve terminals and link vesicle endocytosis and the subsequent round of release has been particularly difficult to study. The recent development of nanoscale-resolution imaging techniques has provided an opportunity to overcome these limitations and begin to reveal the mechanisms controlling vesicle recycling within individual nerve terminals. Here we summarize the recent advances in the implementation of super-resolution imaging and single-particle tracking approaches to study the dynamic steps of the vesicle recycling process within presynaptic terminals.