SEX-DIFFERENCES IN BLOOD-OXYGENATION-LEVEL-DEPENDENT FUNCTIONAL MRI WITH PRIMARY VISUAL-STIMULATION

Objective: The authors evaluated the effect of sex on data derived fro m activation studies using blood-oxygenation-level-dependent (BOLD) fu nctional magnetic resonance imaging (MRI). Method: Gradient echo-echo planar imaging was used to measure BOLD signal response in the primary visual cortex in response to binocular photic stimulation in 16 healt hy, young subjects (eight women and eight men). Results: BOLD signal r esponse was 38% lower in women than in men, and much of the difference was lateralized to the right hemisphere. Conclusions: Lower BOLD sign al response in women may reflect a sex difference in the brain's respo nse to a primary visual stimulation or in the physiology underlying BO LD functional MRI signal changes.