Whole-brain dynamics across the menstrual cycle: the role of hormonal fluctuations and age in healthy women

Recent neuroimaging research suggests that female sex hormone fluctuations modulate brain activity. Nevertheless, how brain network dynamics change across the female menstrual cycle remains largely unknown. Here, we investigated the dynamical complexity underlying three menstrual cycle phases (i.e., early follicular, pre-ovulatory, and mid-luteal) in 60 healthy naturally-cycling women scanned using resting-state fMRI. Our results revealed that the pre-ovulatory phase exhibited the highest dynamical complexity (variability over time) across the whole-brain functional network compared to the early follicular and mid-luteal phases, while the early follicular showed the lowest. Furthermore, we found that large-scale resting-state networks reconfigure along menstrual cycle phases. Multilevel mixed-effects models revealed age-related changes in the whole-brain, control, and dorsal attention networks, while estradiol and progesterone influenced the whole-brain, DMN, limbic, dorsal attention, somatomotor, and subcortical networks. Overall, these findings evidence that age and ovarian hormones modulate brain network dynamics along the menstrual cycle.