Signalling at the synapse: regulation of the post-synaptic response to quantal transmitter release.

Communication between neurones in the central nervous system occurs at specialized synaptic contacts. The strength of a synaptic signal is precisely regulated, and modification of synaptic strength is important in complex brain functions such as learning, and in the formation of appropriate neural maps during development. The fundamental building block of synaptic signalling is the post-synaptic current generated in response to the pre-synaptic release of a quantum of neurotransmitter. The present short review examines the factors that determine the quantal post-synaptic current, and provides direct evidence from a recent study in the author's laboratory that regulation of quantal size is important during development of excitatory transmission in the auditory system.