The brain: use it and lose it

cerebral cortex of humans and other mammals, rapid synapse formation during early postnatal life is followed by a substantial loss of synapses through adolescence and into adulthood. The mechanisms that underlie this phenomenon are unknown. It is generally believed that experience leads to an increase in the number of synapses and that's certainly true in early postnatal life but a study in young adolescent mice paints a very different picture. Long-term sensory deprivation increased dendritic spine numbers (hence synaptic links) by reducing the rate of spine elimination. At distinct stages of life it seems that the more experience one has, the more synapses will be lost in the brain.