SEX-DIFFERENCES IN BRAIN-REGIONS ACTIVATED BY GRAMMATICAL AND READINGTASKS

Do the brains of men and women show similar patterns of functional org anization for language, or are men more strongly lateralized? We used PET to measure cerebral blood flow (CBF) as men and women read real an d nonce verbs, and produced past tense forms. While the overall patter ns of reaction time, error, and brain activation were similar, there w ere also significant sex-related differences in CBF patterns. During t he past tense generation tasks, men showed left-lateralized activation while women recruited bilateral perisylvian cortex, confirming differ ences in functional laterality. During all tasks, women showed higher activation in occipital and/or cerebellar regions, suggesting differen ces in basic reading strategies. We conclude that sex differences in f unctional cortical organization exist in the absence of significant be havioral differences. (C) 1998 Lippincott Williams & Wilkins.