Menstrual cycle modulation of the late positive potential evoked by emotional faces

The objective of the present study was to elucidate the time course and neural basis of facial expression recognition as modulated by the menstrual cycle in women. Event-related potentials (ERPs) associated with recognition of different emotional faces were assessed in 29 healthy women during the premenstrual, post-menstrual, and periovulation phases of the menstrual cycle. Accuracy in recognizing different facial expressions was not affected by the menstrual cycle phase. ERP data indicated that only the late positive potential (LPP) was affected by the menstrual cycle phase for all facial expressions: during the periovulation phase, the amplitude of the LPP (750 to 1,000 msec. post-stimulus) was larger than that during the premenstrual phase. A positive correlation between the amplitude of the LPP and facial expression recognition performance was observed only during the periovulation phase. The present study provides electrophysiological evidence that the LPP evoked by emotional faces is modulated by the menstrual cycle, which may be correlated with fluctuations of ovarian hormones.