VISUAL PROCESSING ACROSS TWO PHASES OF THE MENSTRUAL CYCLE

Throughout the menstrual cycle and associated with fluctuations of sex hormones, changes occur in the visual perception of women. Studies show improved early visual processing during the luteal phase, whereas other studies demonstrate that the highest performance in facial emotion recognition tasks is during the follicular phase. Based on these results, we wondered whether changes in facial emotion recognition throughout the menstrual cycle are caused by a general change in visual processing or by a change in emotion processing. To address this question, we studied women performing a visual emotion recognition task during their follicular and luteal phases. Electroencephalography (EEG) signals of nineteen women with natural and regular menstrual cycles were recorded while observing faces expressing four emotions and a repeated blank-screen control condition. Participants viewed clear and pixel-distorted images and reported the recognized emotion using a keypad. Each woman was recorded in the follicular and the luteal phase of the cycle, verified through estradiol and progesterone blood levels. Behavioral results showed shorter response times during the luteal phase, suggesting facilitated emotion recognition. Regarding EEG, the amplitude of early visually-evoked potentials at occipital electrodes was greater during the follicular phase, with the most pronounced differences, though non-significant, observed in the pixel-distorted and repeated blank-screen blocks. These results show that visual processing changes throughout the menstrual cycle. Altogether, results suggest both visual and emotional processing affect facial emotion recognition and bring us closer to understanding how the female brain functions according to hormonal fluctuations. This work was supported by Fundación-Guillermo-Puelma.