EVENT-RELATED POTENTIALS IN HOMOSEXUAL AND HETEROSEXUAL MEN AND WOMEN- SEX-DIMORPHIC PATTERNS IN VERBAL ASYMMETRIES AND MENTAL ROTATION

To elucidate neurobiological factors related to gender and sexual orie ntation, event-related brain potentials of 20 heterosexual (HT) men, 2 0 HT women, 20 homosexual (HM) men, and 20 HM women were examined for neurophysiological differences. Cognitive tasks which typically elicit sex differences were administered. A mental rotation (MR) task assess ed spatial ability, and a divided-visual-field lexical-decision/semant ic monitoring task (LD/SM) assessed verbal ability and relative degree s of language lateralization. Slow wave activity recorded during MR wa s greater for HT men than for HT women and gay men. N400 asymmetries r ecorded during the LD/SM task revealed differences between men and wom en, but no intrasex differences. (C) 1998 Academic Press.