Language processing is strongly left lateralized in both sexes - Evidence from functional MRI

Functional MRI (fMRI) was used to examine gender effects on brain activation during a language comprehension task. A large number of subjects (50 women and 50 men) was studied to maximize the statistical power to detect subtle differences between the sexes. To estimate the specificity of findings related to sex differences, parallel analyses were performed on two groups of randomly assigned subjects. Men and women showed very similar, strongly left lateralized activation patterns. Voxel-wise tests for group differences in overall activation patterns demonstrated no significant differences between women and men. In further analyses, group differences were examined by region of interest and by hemisphere. No differences were found between the sexes in lateralization of activity in any region of interest or in intrahemispheric cortical activation patterns, These data argue against substantive differences between men and women in the large-scale neural organization of language processes.