There is a series of signaling cascades, MAPK, in the cerebellum that plays a critical role in cerebellum LTD. The MAPK cascade is important in information processing within neurons and other various types of cells. The cascade includes MAPKKK, MAPKK, and MAPK. Each is dual phosphorylated by the other, MAPKKK dual phosphorylates MAPKK and in turn dual phosphorylates MAPK. There is a positive feedback loop that results from a simultaneous input of signals from PF-CF and increases DAG and Ca2+ in Purkinje dendritic spines. Calcium and DAG activate conventional PKC (cPKC), which then activates MAPKKK and the rest of the MAPK cascade. Activated MAPK and Ca2+ activate PLA2, AA and cPKC creating a positive feedback loop. Induced cPKC phosphorylates AMPA receptors and are eventually removed form the postsynaptic membrane via endocytosis. The timescale is for this process is approximately 40 minutes. overall, the magnitude of the LTD correlates with AMPAR phosphorylation.