Long term depression (LTD) in the Purkinje cells of the cerebellum is described as a cellular model for information storage and synaptic plasticity. When two inputs to a Purkinje cell (PC), one from a climbing fiber (CF) and the other from a set of granule cell axons (parallel fiber; PF), are repeatedly associated, there is a decrease in the synaptic strength between PF and Purkinje cells PCs. PF is thought to transmit its signal through glutamate and nitric oxide (NO) and CF is thought to transmit its signal through glutamate, corticotropin-releasing factor (CRF) and insulin-like growth factor I (IGF-I)....