SEXUALLY-DIMORPHIC PATTERNS OF CORTICAL ASYMMETRY, AND THE ROLE FOR SEX STEROID-HORMONES IN DETERMINING CORTICAL PATTERNS OF LATERALIZATION

Cortical asymmetry varies in degree and direction. Sex differences exi st for both dimensions of asymmetry: males tend to exhibit more accent uated asymmetries and stronger right hemisphere dominance compared wit h females, while females typically exhibit more diffuse lateralization patterns and greater left hemisphere bias compared with males. The fo llowing review considers the effects of sex steroid hormones on the se xual dimorphism of cortical lateralization patterns in human and nonhu man animals. Several excellent papers exist which consider sexual dimo rphism in cortical asymmetries for morphological, physiological or fun ctional asymmetries alone. This paper attempts to consider influences of sex steroid hormones on cortical lateralization in a framework that includes morphology, physiology and function. Converging evidence fro m studies that incorporate varying methodologies and theoretical backg rounds indicates that sex steroid hormones are important for influenci ng cortical asymmetry. Although a mechanism has not yet been identifie d, testosterone is the most likely candidate to influence cortical dom inance. (C) 1998 Elsevier Science Ltd. All rights reserved.