Abstract
Converging evidence has accumulated that menstrual cycle and thus hormonal levels can affect emotional behavior, in particular facial emotion recognition. Here we explored the association of ovarian hormone levels and amygdala activation during an explicit emotion recognition task in two groups of healthy young females: one group was measured while in their follicular phase (n=11) and the other during their luteal phase (n=11). Using a 3T scanner in combination with a protocol specifically optimized to reliably detect amygdala activation we found significantly stronger amygdala activation in females during their follicular phase. Also, emotion recognition performance was significantly better in the follicular phase. We observed significant negative correlations between progesterone levels and amygdala response to fearful, sad and neutral faces, further supporting a significant modulation of behavior and neural response by hormonal changes during the menstrual cycle. From an evolutionary point of view this significant influence of ovarian hormone level on emotion processing and an important neural correlate, the amygdala, may enable a higher social sensitivity in females during their follicular phase, thus facilitating socio-emotional behavior (and social interaction) which may possibly facilitate mating behavior as well.