Neural plasticity: Part 2. Postnatal maturation and function-induced plasticity

At birth, the central nervous system has completed most of its early stages of cell division, migration, and specialization. Much of the neural circuitry has been laid down. Neuroblasts are continuing to divide only in limited brain regions. Hence, at birth, most mammals have a nearly full complement of neurons. Nonetheless, the functional capabilities of the central nervous system of the newborn have little resemblance to those of the adult. Postnatal maturation must proceed in the proper sequence and at the proper rate if central nervous system deficits in the adult are to be avoided. Many of the prenatal maturational phenomena described in the previous paper continue well into the postnatal period. The purpose of this paper is to describe some postnatal maturational mechanisms and to show, by selected examples, the important role that function and experience play in central nervous system development.