Electroencephalographic and behavioral correlates of the menstrual cycle effect on the practice of motor imagery
menstrual cycle, motor imagery, action observation, Manual Laterality Recognition Test, motor control, ERD, EEG, Mu, Alpha, Beta, time reaction.
Evidence suggests the female sex hormones (FSHs) effect on neural circuits involved in motor control, performance in manual dexterity and motor coordination tests and neurological diseases with motor impairment. There is a lack of studies that investigate its effects on motor cognitive processing. The sensorimotor rhythm also
known as mu rhythm (with its alpha: 12-13Hz; and, beta components: 15-30Hz) observed in electroencephalography (EEG) is considered a window of opportunity to investigate the modulation of cortical areas involved in planning motor. The mu rhythm can be induced by activities such as kinesthetic motor imagery (MI) and action observation (OA), among others. Another tool used to investigate motor cognitive processing is the Manual Laterality Recognition Test (TRLM). It is able to modulate the P100 and P300 components of the Event-Related Evoked Potential (P300-ERP) in the EEG and it has behavioral measures that allow making inferences about cognitive processes related to the spatial manipulation of body parts (in this specific case, the hands). This process is known as implicit motor imagery. In this study, we investigated whether the cortical activity and behavioral measures related to the cited tasks are modulated according to the menstrual (low hormone levels), follicular (high estrogen levels) and luteal (high progesterone levels) phases of the menstrual cycle of 31 women. The beta event-related desynchronization (beta-ERD) on the bilateral frontal region during MI practice was greater in the follicular phase when compared to the menstrual and luteal phases, suggesting the effect of estrogen on areas of motor cognitive processing control. No difference between the phases of the menstrual cycle was observed on the mu rhythm during the practice of AO, nor on the alpha component during MI. Behavioral analysis indicated better performance in MLRT during the follicular and luteal phases when compared to the menstrual phase. This result contradicts studies that demonstrate reduced object spatial manipulation ability associated with FSHs and suggests that the FSHs effect on motor cognitive components, possibly absent in object spatial manipulation, is able to favor performance in MLRT.