Introduction: Investigating sex-related neurophysiological differences across menstrual cycle phases is important. Sex steroid hormones associated with the menstrual cycle influence both brain function and brain structure; therefore, these factors should be considered in studies involving women participants. Objective: This study examined the impact of sex-related differences across menstrual cycle phases on stimulus recognition processes in the auditory and somatosensory modalities. Methods: Forty-four participants (25 men and 19 women) underwent assessment of auditory and somatosensory evoked potentials under control and simple reaction task conditions. Auditory evoked potentials were elicited using pure tones delivered bilaterally through headphones. Somatosensory evoked potentials were elicited via electrical stimulation of the right index finger. In both task conditions, the interstimulus interval was randomized between 5 and 15 seconds for both sensory modalities. Results: In the auditory modality, the N1 amplitude was significantly larger in women during the ovulatory phase under the control condition than in men. In contrast, in the somatosensory modality, the P100 amplitude was significantly larger in women during the menstrual phase under the simple reaction task condition than during the ovulatory phase. Conclusion: Sex-related differences modulated by menstrual cycle phases exert distinct effects on stimulus recognition processes in the auditory and somatosensory modalities.
Anazawa et al. (Sun,) studied this question.