User:Rob Malenka/Proposed/Long-term depression
This article is in preparation.
Long-term depression (LTD) is a weakening of a synapse after a short series of presynaptic action potentials or asynchronous presynaptic and postsynaptic activity. LTD is distinguished in homosynaptic LTD, heterosynaptic LTD and associative LTD.
Types of LTD
- homosynaptic LTD: LTD is confined to the synapse where the short series of action potentials arrived.
- heterosynaptic LTD: LTD affects also other synapses of the respective cell.
- associative LTD: Asynchronous pre- and postsynaptic increase of intracellular calcium causes LTD.
Occurrences of LTD
- Purkinje cells: Purkinje cells receive unspecific excitatory input from parallel fibers. But each purkinje cell receives a synapse from a single climbing fiber. Activation of a climbing fiber results in a reduction of the excitability of the according Purkinje cell. This LTD is related with the accomodation of the vestibo-ocular reflex to optical conditions.