Facial emotion recognition and amygdala activation are associated with menstrual cycle phase

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.

Figure 1

Example of the explicit emotion recognition task performed during scanning. Subjects were instructed to indicate the correct emotion by button press.

Figure 2

Results of whole-slab analysis showing activation maps of random effects analysis on one coronal slice (Y = 0) comprising the amygdala for FPG (a) and for LPG (b) (threshold: t = 3.17 and p < 0.005 uncorrected).

Figure 3

Results from the ROI analysis: mean parameter estimates (with S.E.M.) for left and right amygdala for each emotion across FPG and LPG. Repeated measures ANOVA revealed a significant phase effect (p = 0.049) indicating stronger amygdala activation in the follicular group (FPG). Post hoc tests for the significant emotion-by-phase-by-laterality interaction demonstrated significant differences for disgust bilaterally (left, p = 0.038; right, p = 0.001) and for right amygdala activation during happy face processing (p = 0.037). Significant differences are marked with an asterisk.

Figure 4

Recognition accuracy with standard error of mean for all emotions across females in the follicular phase (FPG) and females in the luteal phase (LPG) is presented in (a). Mean percent correct across all stimuli for FPG and LPG females are illustrated in (b). Results of the repeated measures ANOVA revealed a significant phase effect (p = 0.011) with a better performance of the FPG group—illustrated with an asterisk in (b) without any significant emotion-by-phase interaction (p = 0.373).