How many vesicles does a single spike release? · Grey Matter

At a typical synapse in the cortex or hippocampus, usually none or one: each release site has a probability of release of roughly 0.1 to 0.3 at low firing rates, and only sometimes do two or more vesicles go together.

How many vesicles does a single spike release?

At a typical synapse in the cortex or hippocampus, usually none or one: each release site has a probability of release of roughly 0.1 to 0.3 at low firing rates, and only sometimes do two or more vesicles go together. Reliability comes from numbers, since a neuron receives input through many such synapses at once. A motor nerve terminal is built the other way, with hundreds of release sites, and one spike releases tens of vesicles (about 20 to 60 at human neuromuscular junctions, more in larger muscles of other animals), enough to fire the muscle fibre every time. A range such as one to two hundred vesicles per spike mixes these two very different kinds of synapse.