What physically changes at a synapse that has been potentiated? · Grey Matter

Mostly the postsynaptic side gains AMPA receptors: more of them are inserted and held at the synapse, and existing ones are phosphorylated so each conducts more, so one vesicle of glutamate now produces a larger current.

What physically changes at a synapse that has been potentiated?

Mostly the postsynaptic side gains AMPA receptors: more of them are inserted and held at the synapse, and existing ones are phosphorylated so each conducts more, so one vesicle of glutamate now produces a larger current. Within minutes to hours the spine head grows, its scaffold of proteins enlarges to hold the new receptors, and in late LTP new proteins are made to keep the change. Some forms also raise the probability of release on the presynaptic side. Synapses that had NMDA receptors but almost no AMPA receptors (silent synapses) can be switched on this way, which is common in development.