Effects of gender, digit ratio, and menstrual cycle on intrinsic brain functional connectivity: A whole-brain, voxel-wise exploratory study using simultaneous local and global functional connectivity mapping.

Introduction: Gender and sex hormones influence brain function, but their effects on functional network organization within the brain are not yet understood.

Methods: We investigated the influence of gender, prenatal sex hormones (estimated by the 2D:4D digit ratio), and the menstrual cycle on the intrinsic functional network organization of the brain (as measured by 3T resting-state functional MRI (rs-fMRI)) using right-handed, age-matched university students (100 males and 100 females). The mean (±) age was 20.