Language processing is strongly left lateralized in both sexes

Evidence from functional MRI

Julie A. Frost1, Jeffrey R. Binder1,2, Jane A. Springer1 and
Thomas A. Hammeke1

Patrick S.F. Bellgowan1, Stephen M. Rao1,2 and Robert W. Cox3

1 Departments of Neurology, 2 Cellular Biology and Anatomy and 3 Biophysics Research
Institute, Medical College of Wisconsin, Milwaukee, Wisconsin, USA

Correspondence to: Jeffrey R. Binder, MD, Department of Neurology, Medical College of
Wisconsin, 9200 West Wisconsin Avenue, Milwaukee, WI 53226, USA E-mail:
jbinder@post.its.mcw.edu

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.