Synaptic receptor dynamics: from theoretical concepts to deep quantification and chemistry in cellulo.

Synapses, although seemingly stable, undergo constant rearrangements and exhibit a high level of dynamic movement as revealed by molecular imaging. This apparent biological paradox has emerged as a key element enabling synaptic plasticity. The development of super-resolution imaging combined with theoretical modelling has advanced our understanding of the structure and molecular dynamics of synapses. It is now feasible to determine at the level of a single synapse the number of molecules present, their characteristic dwell times, as well as the energies of molecular interactions between synaptic components. This deep quantification of synapses provides access to the chemical determinants that regulate the numbers of receptors and hence the function of synapses at a mechanistic level.