No sex differences in auditory and somatosensory P50 sensory gating in relation to estradiol levels

Although P50 sensory gating has been widely investigated, few studies have simultaneous examined sex-related differences, menstrual-related distress, and differences between sensory modalities. This study aimed to investigate sex-related differences in P50 sensory gating separately in the auditory and somatosensory modalities, with particular attention to their associations with 17β-estradiol (E2) levels. In addition, we examined the correlation between menstrual-related symptoms assessed using the menstrual distress questionnaire (MDQ) and Salivary alpha-amylase (sAA) activity. Fifty-three healthy undergraduate and graduate students participated in this study. Auditory evoked potentials were elicited by pure tones delivered bilaterally via headphones, whereas somatosensory evoked potentials were elicited via electrical stimulation of the right median nerve. In both modalities, paired stimuli were presented with an interstimulus interval of 500ms. At least fifty paired stimuli of auditory and somatosensory stimuli were presented separately, with an inter-pair interval of 8 s for each modality. E2 levels were significantly higher in women during the late follicular phase than in men. However, no significant differences in P50 sensory gating were observed in either the auditory or somatosensory modality among men, women in the early follicular phase, and women in the late follicular phase. In addition, no significant correlation was found between MDQ and sAA activity. These findings suggest that E2 did not influence auditory and somatosensory P50 sensory gating and that menstrual-related distress was not clearly associated with physiological stress as reflected by sAA activity.