ABSTRACT
No one would argue with the statement that the nervous system of mammals is more plastic while it develops than when it matures. In fact, the term plasticity, defined as the “capacity for being molded or altered.” (Page 648, MerriamWebster 1971) takes its root from “plasia” meaning to form, develop or mold. This derivation also raises a question concerning the definition of developmental plasticity. Can one usefully distinguish between the two processes or are manipulations that reveal plasticity simply uncovering basic rules or mechanisms of normal development? In this chapter we will argue that it is useful to distinguish between these processes even though they may reflect common underlying mechanisms. We will define neural plasticity in development broadly as the potential for the maturing system to change its neural phenotype based upon altered patterns of connections or activity. We will focus on examples of plasticity in the development of the mammalian visual system, drawing upon studies of other systems where necessary to illuminate the mechanisms involved.
