Abstract: The current study examined subjective ratings and evoked brain potentialsto the emotional value of picture stimuli collected from 30 female subjects indifferent hormonal phases of their menstrual cycles. The emotional value of thestimuli was manipulated by five slide categories, the content were ordinarypeople, babies, dermatological cases, male models and female models. It wasfound that only the P3 component of evoked brain potentials varied with theemotional value of the stimuli and hormonal phases. The picture categoriesthat were rated as pleasant and unpleasant (babies and dermatological cases)elicited significantly larger P3 amplitude than the neutral category (ordinarypeople). The P3 responses to babies and male models in high progesterone ph-ase were larger than those in low progesterone phase. High progesterone phase wasalso associated with a decrease in the rating scores on eroticism of all slidecategories. An increase in the pleasantness of all categories was evident whenestrogen levels were high. The above experimental results suggest that P3component is sensitive to the emotional value of a stimulus and reflects theadaptive changes in cognitive and emotional processes regulated by physiologi-cal status.

Key words: Cognition, Emotion, Menstrual cycle, Steroid hormones, Evoked brain potentials, Adaptation