The experiments in this proposal are designed to examine the development of connectivity in the prefrontal cortex of the rhesus monkey brain. Recent advances in understanding the connections between the two lobes of the frontal cortex (cortico.cortical connec tions) in mature monkeys make this a model system for examining the rules and mechanisms which govern their development. Dr. Schwartz will conduct experiments to provide detailed information on two aspects of development: (1) the tempo and pattern of ingrowth of cortico.cortical axons in the prefrontal cortex, and (2) the generation, targets and tempo of proliferation of synaptic contacts arising from callosal axons and the relationship of these events to columnar organization. These studies will examine fetal and neonatal monkeys using the neuroanatomical tracers HRP and tritiated amino acids at the light and electron microscope level. The results of these experiments will provide important new information on aspects of axonal growth and connectivity formation in the cerebral cortex of developing primates. The cortico.cortical connections in the prefrontal cortex of primates are highly developed. Similarities in the pattern of behavioral impairments found following damage to the frontal lobes in humans and monkeys suggest that the monkey prefrontal cortex may provide an important model for understanding the structure and function of cognitive functions on humans.
