How does PMS affect the brain's response to positive emotions?

This study characterize mood and emotional regulation in women with premenstrual syndrome (PMS) using near-infrared spectroscopy (NIRS) and mood assessments. Hemodynamic responses in the prefrontal cortex (PFC) were measured while participants viewed emotion-inducing images during both the follicular and luteal phases of the menstrual cycle. Emotional valence and arousal ratings for each image were obtained immediately after the task. In addition, mood states were evaluated prior to the task using the Profile of Mood States Second Edition (POMS2). Forty-six women completed the procedures across both menstrual cycle phases. After excluding five participants diagnosed with premenstrual dysphoric disorder (PMDD), data from 41 participants (non-PMS: n = 25, PMS: n = 16) were analyzed. During the follicular and luteal phases, the PMS group showed significantly lower integrated oxyhemoglobin (oxy-Hb) responses to positive emotional stimuli in the right prefrontal region compared to the non-PMS group (follicular phase: p = .03, r = 0.35; luteal phase: p < .001, r = .0.52). These r values represent effect sizes (rank-biserial correlations) corresponding to the Mann–Whitney U tests. No significant group differences were found in the left prefrontal region and response to negative stimuli. Based on POMS2 scores, the PMS group showed significantly higher scores on six negative mood scales and a lower score on one positive mood scale during the follicular phase. During the luteal phase, only one negative mood subscale score was significantly higher in the PMS group. Group differences in subjective emotional valence and arousal ratings were evident only during the follicular phase. These findings suggest that women with PMS exhibit attenuated neural responses to positive emotional stimuli and altered mood states even during the follicular phase when symptoms are often not consciously recognized. This may highlight the possibility that early-phase emotional dysregulation may precede overt symptom manifestation in PMS, providing insights into its temporal dynamics.

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