On females' lateral and males' bilateral activation during language production: a fMRI study.

This study focuses on sex/gender and language in fMRI research. We explore the question of similarities and differences in 22 men and 22 women, respectively, in a fMRI language production task of fluent narration in which covert language production was contrasted with an auditory attentional task. In women, a left-lateralised activation concentrated in BA 44 while in men activation was more frontal in BA 45 and more often bilateral. This result is the opposite of those shown so far. Interestingly, the effect is only significant at the level of group analysis; it disappears when analysing activation at the level of the individual subject. We argue that sex/gender differences in the brain should be regarded much more critically, due to the numerous variables interacting and thus confounding with sex/gender. Our present study, too, cannot resolve the controversy about the existence of sex/gender similarities and differences in fMRI-language investigations.