Long-term potentiation (LTP) is a robust form of synaptic enhancement that far outlasts the duration of active stimulus. LTP represents the most intriguing form of synaptic memory, mainly due to its long duration and associative properties, and is held to be involved in learning processes at the behavioural level. Advances in the understanding of central synaptic functions are now extending interest in LTP to the fine detail of its synaptic mechanisms.