Synaptic augmentation

Augmentation is one of four components of short-term synaptic plasticity that increases the probability of releasing synaptic vesicles during and after repetitive stimulation such that

when all the other components of enhancement and depression are zero, where ${\displaystyle A}$ is augmentation at time ${\displaystyle t}$ and 0 refers to the baseline response to a single stimulus. The increase in the number of synaptic vesicles that release their transmitter leads to enhancement of the post synaptic response. Augmentation can be differentiated from the other components of enhancement by its kinetics of decay and by pharmacology. Augmentation selectively decays with a time constant of about 7 seconds and its magnitude is enhanced in the presence of barium. All four components are thought to be associated with or triggered by increases in internal calcium ions that build up and decay during repetitive stimulation.

During a train of impulses the enhancement of synaptic strength due to the underlying component ${\displaystyle A^{*}}$ that gives rise to augmentation can be described by

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