(1 Beijing Key Lab of Applied Experimental Psychology, Beijing Normal University, Beijing 100875, China) (2 State Key Laboratory of Cognitive Neurosciences and Learning, Beijing Normal University, Beijing 100875, China) (3 Research Center of Emotion Regulation, Beijing Normal University, Beijing 100875, China) (4 Beijing University of Chinese Medicine, Beijing 100029, China)
Women experience dramatic fluctuations in progesterone and estradiol during menstrual cycles, which will likely influence their mood. The subjective experience and neural responses towards emotional stimuli of women who suffer from premenstrual syndrome (PMS) seemed to differ across menstrual cycles. However, it remains unknown that if women without PMS will have mood swings during a menstrual cycle. Additionally, some studies argued that neuroticism was closely associated with PMS. But it is still unclear whether neurotic women without PMS would have different responses towards emotional stimuli in different phases of menstrual cycle like women with PMS. The current study was designed to investigate the influence of neuroticism on the subjective experience and physiological responses towards emotional stimuli in the non-PMS sample across a menstrual cycle. We hypothesized that neurotic women would have more intense subjective experience and physiological responses towards emotional stimuli, especially in the premenstrual phase. Forty-one right-handed female with regular menstrual cycle took part voluntarily in this within-subject study. The results of Eysenck Personality Questionnaire (EPQ) divided this sample into the high neuroticism group (HN group, n = 16) and the low neuroticism group (LN group, n = 25). Each participant performed a film watching and evaluating task three times during mid-late luteal, menstrual and late ovulation phases respectively. 12 film clips were selected. Among them, nine 3-minute film clips were supposed to evoke amusement, sadness, and anger (3 clips for each emotion) and 3 film clips were neutral. For each visit, the participant would watch 4 film clips randomly selected from 12 film clips, one for each emotion and a neutral one, and the order of clips was counter-balanced. Each time the participant came to the lab and relaxed for 3 minutes (baseline), then she watched a film clip and completed the emotion inventory to evaluate how they felt about the clip. She was then asked to relax for another 3 minutes to recover from the emotional arousal. The physiological responses including heart rate, galvanic skin response (GSR) and respiratory rate were recorded at this time. This procedure was repeated until all 4 film clips (one for each emotion and a neural film) were viewed. The results showed that there was a significant interaction between menstrual cycle and group membership for self-reported anger and disgust in response to angry films. The HN group scored lower in self-reported anger and disgust than the LN group only in the mid-late luteal phase, and there was a significant effect of menstrual cycle in HN group but not in LN group for self-reported anger. We calculated rate of change for the analysis of heart rate and found a significant effect of menstrual cycle for the HN group but not for the LN group when they were watching neutral and sad films. The rate of change in the LN group was significantly greater than that in the HN group in the mid-late luteal phase, but not in the other two phases. We also calculated rate of change for the analysis of respiration rate and found that the change of rate is significantly greater for the HN group than that for the LN group, but only in the menstrual phase. Taken together, the subjective experience and physiological responses towards negative emotion during menstrual cycles seem to be more influential for neurotic women than for those who are low in neuroticism. Furthermore, neurotic women seemed to be less vulnerable to negative emotion during their mid-late luteal phase than during other phases. Sensitive response of neurotic women to the fluctuation of progesterone during menstrual cycles may be one of the reasons that account for their mood change.