Cerebral Laterality as a Determinant of Behavioral Function and Dysfunction

Abstract

The human brain has been shown to be laterally specialized with regard to a variety of functions. The genetic determinants of this specialization have also been explored. There has been some emphasis placed on individual differences in the degree of this specialization and the determination of its significance for lending a predisposition toward behavioral dysfunction and psychiatric disease. Whereas many animal models of human behavioral dysfunction have been developed, there has been relatively little interest and consequently relatively little data bearing on the issue of how differences in brain asymmetry in animals may be important parameters in determining the modeled dysfunction. However, over the past 15 years, data have accumulated to suggest that morphologic, chemical, and behavioral indices of brain asymmetry are present in animals. It has also been suggested that variations in the magnitude and direction of these indices are determined by a complex interaction of genetic, hormonal, and experiential factors. Individual differences in cerebral laterality have been shown to covary with or predict individual differences in drug responses, spatial behavior, and stressor reactivity as well as susceptibility to stressor-evoked behavior pathology and drug abuse predilection. Such findings suggest that it is possible to study genetically influenced individual differences in lateralized brain function as they exist in animals and to relate these differences to those seen in humans.