Series on Mental Retardation held in Oxnard, California, in January 1974. This book compiles research on neurobiological findings which might lead to an understanding of the basic processes underlying the phenomena of mental deficiency and related aspects of human development. The topics discussed include the timing of major ontogenetic events in the visual cortex of the rhesus monkey; neuronal sprouting after hippocampal lesions; synaptic and dendritic development and mental defect; and CNS maturation and behavioral development. The neuronal control of neurochemical processes in the basal ganglia; nigrostriatal projections and the “dopamine receptor”; and effects of caudate nuclei removal in cats are also deliberated. This text likewise covers the effects of caudate nuclei removal versus frontal cortex lesions in kittens and role of biochemistry in research on mental retardation This publication is beneficial to medical practitioners and students concerned with mental retardation.