Coordinated pre- and postsynaptic changes involved in developmental activity-dependent synapse elimination

Abstract

A central problem for current neuroscience is to develop an unifying mechanistic hypothesis for the different forms of nervous system plasticity. In addition to the short-term adaptations of synaptic activity like facilitation, the various models that have been studied include long term potentiation (LTP), long term depression (L'TD), various forms of behavioral conditioning such as eye-blink conditioning, sensitization and desensitization and the synaptic and neuronal pruning or removal that is a prominent aspect of development of the nervous system. It seems to be the case that several different mechanisms are involved in these different forms of activity dependent changes in neural function and circuit performance; certainly the relatively simple Hebb model of 1949 (Hebb, 1949) serves as only the broadest guide to understanding such changes. These variations notwithstanding, some general model for understanding neuro-plasticity is emerging and should be a useful conceptual framework for guiding future experiments.