synaptic plasticity is a term, which describes the activity-dependent change of the strength of the synaptic transmission. These changes can be caused both by changes of the morphology as well as for the physiology of the synapse. Synaptic plasticity is an important research article of the neuro sciences. Synaptic plasticity is therefore of large interest, since it is considered as a possible mechanism to learning processes and memory.
See also: Hebb' learning rule
to the explanation of the term
- synaptic activity/transmission: Synapses can rest or be active. At an active synapse presynaptic ending is excited, i.e., there Aktionspotenziale arise . It comes to the release of transmitter into the synaptic gap and its connection at receptors of the postsynaptic diaphragm. Thereby in the postsynaptic neuron if an answer is caused, synaptic transmission took place. The answer must not necessarily in oneAktionspotenzial exist, but are frequently under-smolder-lie.
- activity-dependently: That means that those changes of the synapses are regarded, which have their activity as a cause. In contrast to it there is z. B. development-conditioned changes of synapses, during growth and the differentiation of the nervous system take place anddo not presuppose necessarily also synaptic activity.
- Strength of the transmission: Thus it is meant that an individual Aktionspotenzial at the presynaptic Endknöpfchen in the postsynaptic neuron can cause a differently strong change of the Membranpotenzials. The more largely this change, the more strongly the transmission (and in reverse).
Depending upon duration of the synapticOne differentiates changes after a certain form of the synaptic activation between briefer and long persisting plasticity (short term plasticity and long term plasticity).
- Short term plasticity: The change of the transmission strength stops some milliseconds until at the most some minutes.
- Long term plasticity:The strength of the transmission changesfor many minutes until some hours, possibly lifelong.
One calls the reinforcement of the synaptic transmission by synaptic plasticity exponentiation, the weakening as depression. (The latter is not to confound with the disease picture of the depression). Depending upon duration one speaks of long-term exponentiation (long term potentiation, LTP), short time exponentiation (short term potentiation, STP), long-term depression (long term depression, Ltd.) and short time depression (short term depression, STD).
Synaptic plasticity can be postsynaptically caused both prä and.
- presynaptically: The quantity of the transmitter set free per Aktionspotenzials changes.
- postsynaptically: The size of the postsynaptic answer to a certain quantity of transmitter changes. That e.g. happens. by change of the quantity of postsynaptic transmitter receptors, by the modification of these receptors (frequent by phosphorylation or Dephosphorylierung) or by the formation of enzymes, those thatBehavior of the neurotransmitters in the synaptic gap Prä
and postsynaptic changes change can occur at the same time.
The direction of the change of the synaptic transmission and the mechanism, by which it is made, are specific for certain synapses and determined kinds of the synaptic activity.
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