Synapse elimination and plasticity in developing human cerebral cortex.

TLDR

During human cortical development, neurons, dendrites, and synapses are overproduced prenatally and in early infancy, providing a surplus that underlies early brain plasticity. The study aims to leverage this developmental plasticity to retrain impaired functions. Synaptic density peaks at one year of age and then declines rapidly during preschool years through progressive synapse elimination.

Abstract

Overproduction of structures including neurons, dendrites, and synapses occurs during development in many neural systems. In human beings cerebral cortex synaptogenesis takes place prenatally and during early infancy. Maximum synaptic density, absolute number of synapses, and number of synapses per neuron are reached by age 1 year. Subsequently, there is progressive synapse elimination that is most rapid during the preschool years. Overproduction of synapses may impart plasticity to the brain of young children. This property of developing brain may be exploited for retraining when function is impaired. An example is the reversal of amblyopia by forcing strabismic children to use their squinting eye.