Molecular Mechanism of Long-term Depression
Long-term depression also works through associative properties although it is not always the reverse process of LTP. LTD in the cerebellum requires a coincident stimulation of parallel fibers and climbing fibers. Glutamate released from the parallel fibers activates AMPA receptors which depolarize the postsynaptic cell. The parallel fibers also activate metabotropic glutamate receptors that release the second messengers IP3 and DAG. The climbing fibers stimulate a large increase in postsynaptic Ca2+ levels when activated. The Ca2+, IP3, and DAG work together in a signal transduction pathway to internalize AMPA receptors and decrease the sensitivity of the postsynaptic cell to glutamate (Purves 2004).
Read more about this topic: Coincidence Detection In Neurobiology, Synaptic Plasticity and Associativity
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