Shift of functional cerebral asymmetry during the menstrual cycle.

This study investigated whether for females, who are said to be less strongly lateralized for cognitive functions than men, hemispheric superiority might depend on the phase of the menstrual cycle. The results show that while asymmetry in lexical decisions did not change throughout the menstrual cycle, asymmetry in face perception decreased linearly from a large right hemisphere superiority during menstruation to a small left hemisphere superiority during the premenstrual phase. This is seen as being relevant not only for the discussion of sex differences in cerebral asymmetry but also for the concept of cerebral organization in general.