Long-term depression (LTD) is a type of synaptic plasticity in which the efficacy of signal transmission across a synapse is persistently reduced after a certain triggering activity. LTD in the cerebellum was proposed as a theoretical possibility around 1970 and was detected a decade later (Ito, Sakurai, and Tongroach, 1982). So far, several subtypes of LTD varying in cellular and molecular mechanisms have been found in the cerebellum, hippocampus, and neocortex. LTD occurs not only in excitatory synapses, but also in inhibitory ones. LTD may weaken or functionally interrupt useless or erroneous synaptic connections between neurons, providing an opposing mechanism against long-term potentiation (LTP) in various forms of learning and memory.

Induction and Observation of Ltd

The various forms of LTD revealed to occur in the cerebellum, cerebellum-like structures in fish, hippocampus and neocortex have the...