Properties
NMDA receptor-dependent LTP exhibits several properties, including input specificity, associativity, cooperativity, and persistence.
- Input specificity
- Once induced, LTP at one synapse does not spread to other synapses; rather LTP is input specific. Long-term potentiation is only propagated to those synapses according to the rules of associativity and cooperativity. However, the input specificity of LTP may be incomplete at short distances. One model to explain the input specificity of LTP was presented by Frey and Morris in 1997 and is called the synaptic tagging and capture hypothesis.
- Associativity
- Associativity refers to the observation that when weak stimulation of a single pathway is insufficient for the induction of LTP, simultaneous strong stimulation of another pathway will induce LTP at both pathways.
- Cooperativity
- LTP can be induced either by strong tetanic stimulation of a single pathway to a synapse, or cooperatively via the weaker stimulation of many. When one pathway into a synapse is stimulated weakly, it produces insufficient postsynaptic depolarization to induce LTP. In contrast, when weak stimuli are applied to many pathways that converge on a single patch of postsynaptic membrane, the individual postsynaptic depolarizations generated may collectively depolarize the postsynaptic cell enough to induce LTP cooperatively. Synaptic tagging, discussed later, may be a common mechanism underlying associativity and cooperativity. Bruce McNaughton argues that any difference between associativity and cooperativity is strictly semantic.
- Persistence
- LTP is persistent, lasting from several minutes to many months, and it is this persistence that separates LTP from other forms of synaptic plasticity.
Read more about this topic: Long-term Potentiation
Famous quotes containing the word properties:
“A drop of water has the properties of the sea, but cannot exhibit a storm. There is beauty of a concert, as well as of a flute; strength of a host, as well as of a hero.”
—Ralph Waldo Emerson (1803–1882)
“The reason why men enter into society, is the preservation of their property; and the end why they choose and authorize a legislative, is, that there may be laws made, and rules set, as guards and fences to the properties of all the members of the society: to limit the power, and moderate the dominion, of every part and member of the society.”
—John Locke (1632–1704)