Menstrual cycle, cognition and restingstate activity of brain in schizophrenia: A functional mri study.

Menstrual cycle is a favorable model for examining the influence of ovarian hormones on cognition, emotion and brain functions. Ovarian hormones are shown to have important effects on task-related brain activity, but few studies investigated their influences on functional connectivity at rest, and findings are inconsistent. However, different influences of ovarian hormones on schizophrenia were reported. The present study investigates resting state functional connectivity (Rs-FC) alterations related to menstrual cycle phase and/or hormone levels, and aims to contribute to the understanding of the effects of ovarian hormones on the pathogenesis of schizophrenia and brain functions. Therefore, schizophrenia patients (N=13) (32±7,67) and healthy controls (N =13) (30,08±7,27) were examined in terms of hormone levels, clinical symptoms, cognitive functions and resting state fMRI findings in follicular and luteal phases. Results revealed that patients had lower progesterone levels during luteal phase compared to healthy controls (p<0.05). The severity of psychotic symptoms didn't change between phases for the patients. Furthermore, no phase-related alterations existed in Rs-FC networks in both groups. However, estradiol and progesterone levels were associated with temporal network connectivity in patients; the default mode, left-frontoparietal, and executive control networks connectivity in healthy controls. Results indicate that menstrual cycle effects were observed in healthy controls rather than schizophrenia patients; and that the findings for the patient group may be associated with the mechanism of schizophrenia. These imply that differentiating menstrual cycle effects is difficult in a severe disorder such as schizophrenia. This is the first study investigating Rs-FC together with hormonal, clinical and cognitive findings in schizophrenia.