Efeito do ciclo menstrual sobre o ritmo beta da eletroencefalografia durante tarefa de coordenação motora

Abstract

The female sex hormones estrogen and progesterone fluctuate rhythmically throughout the menstrual cycle. Because they are lipid-based, these hormones can cross the blood-brain barrier and influence central nervous system activity. This study aims to examine how these hormones affect cerebral cortex activity, particularly the beta rhythm (15 to 30 Hz), during a motor coordination task. To conduct the study, 30 women aged 18 to 30 with regular menstrual cycles were recruited. Each participant attended three experimental sessions, each scheduled during a different phase of the menstrual cycle: menstrual, follicular, and luteal. During each session, participants performed the Finger Tapping Test in both simple and sequential configurations, using both their right and left hands. The study found no statistically significant main effect of menstrual cycle phase on cortical activity during the task. However, there was a significant interaction effect between cycle phase, cerebral hemisphere, and hand laterality in the frontal region of the cerebral cortex, based on beta rhythm analysis. The results suggest that female sex hormones influence interhemispheric communication in a brain region involved in movement planning, which receives input from the basal ganglia, an important structure for motor coordination. In less complex tasks, increased progesterone levels reduce cortical asymmetry, while in more complex tasks, the opposite effect is observed.