We are currently involved in evaluating the effects of chronic administration of centrally acting drugs upon early brain development in experimental animals. Since human infants often receive neurotropic drugs on a chronic basis, the importance of this research lies in its implications for clinicians. Specifically, we will evaluate early chronic administration of phenobarbital, diphenylhydantoin, amphetamines, and carbamazepine. Our assessments will be both biochemical and behavioral. Among the biochemical parameters studied will be regional brain weights, DNA, RNA, protein, and cholestorol content of regional areas, as well as initial examination of specific CNA systems (i.e. monoamine systems). The behavioral parameters will include the development of social behaviors, measurement of learning abilities, and the development of activity levels.