Morphological consequences of prenatal injury to the primate brain.

Publisher Summary One of the most challenging questions facing neurobiology and psychiatry is the degree of latitude that is permissible in the relationship between neural structure and functional capacity. This century has witnessed radical shifts in opinion concerning this basic question and, in particular, the matter of how experience moulds human behavior and intelligence. Clarification of the modifiability of the mammalian nervous system, especially in our own species in whom the qualities of plasticity and adaptability are paramount, will not be satisfactorily answered until we have a firm idea of the organization of the neural circuitry subserving cognitive and other higher order cerebral processes in the primate nervous system, knowledge of how and when neural connections develop, and finally, the degree of their modifiability during the course of normal and pathological development. The studies on the consequences of prefrontal lesions in fetal rhesus monkeys described in this chapter have revealed that the primate brain is extraordinarily malleable in response to external forces and thus displays a degree of neuronal plasticity that is comparable if not greater than neuronal modifications that have been described in numerous non-primate mammals. The present findings in monkeys are particularly instructive because they reveal changes at both the gross morphological and cellular levels in a slowly developing gyrencephalic brain which is similar to the human cerebrum. The findings, therefore, bear both directly and indirectly on understanding of pediatric neuropathological disorders, as well as on the normal development of the human brain.