Long-term Potentiation

Long-Term Potentiation is the process by which repetitive stimulation at a synapse increases the efficiency of transmission at that synapse. This process depends on the diffusion of calcium ions through NMDA receptors. Neurotransmitter glutamate diffuses across synaptic cleft and it binds to two inotropic receptors. The AMPA receptor is a sodium ion channel and so triggers an EPSP. Depending on what modulation is going on in that cell body, the EPSP may or may not trigger an action potential. The NMDA receptor is blocked by magnesium ions and so has no effect, however, repetitive stimulation results in greater depolarization and magnesium ion is ejected from the NMDA receptor. This enables calcium ions flow through the NMDA receptor, it is the diffusion of calcium ions cause the postsynaptic cell to become more sensitive to glutamate and enhances glutamate release from the presynaptic cell .