Chapter 4 – Synaptic Development

Synapses are specialized sites of communication between neurons and their targets. The presynaptic and postsynaptic compartments must be properly aligned and maintained in order for the optimal functioning of the nervous system. Synaptogenesis consists of four major steps: (1) neurite elongation and guidance (in which axons and dendrites of partner neurons grow into apposition with each other); (2) synaptic differentiation (in which the appropriate transmission machinery is assembled); (3) synaptic refinement (in which functional connections are maintained and extraneous connections eliminated); and (4) synaptic maturation and maintenance (an ongoing process through age that ensures the stability of the brain). Disruption at any phase leads to synaptic defects that can have neurological/psychiatric consequences. The general process of synaptic development is largely conserved across species. Here, we highlight what is known about mammalian synaptogenesis, and how failures in synaptic development can result in a variety of neurological and psychiatric disorders.