Question

Explain why changes in Ca²⁺ levels are fundamental in short-term synaptic changes such as facilitation, synaptic depression, augmentation, and posttetanic potentiation. What can these short-term changes contribute to the study of learning and memory?

Answer 1

The change in Ca2+ level is fundamental in short term synaptic changes like facilitation, synaptic depression, augmentation and post-tetanic potentiation. It was found that vesicle depletion and inactivation of release sites and calcium channels is responsible for contributing to these forms of synaptic depression. There is reduction in the calcium influx and it is activity dependent which might lead to depression at the synapses. The neurotransmitter release is completely dependent on the calcium release and hence even a small change generally leads to calcium entry and significant pre-synaptic plasticity.

During Post-tetanic Potentiation there is a decrease in the paired pulse plasticity and it results due most increase in the pre-synaptic calcium entry or changes in the release machinery itself. It is evident that due to depletion of the readily releasable vesicles, inactivation of the release sites and inactivation of the pre-synaptic calcium channels, it leads to all of the conditions.