Poster F21, Tuesday, March 27, 8:00-10:00 am, Exhibit Hall C
Sex-related differences in behavioral and neural processing of facial threat cues via magnocellular and parvocellular pathways.
Hee Yeon Im1,2, Reginald Adams, Jr3, Cody Cushing1, Jasmine Boshyan1,2, Noreen Ward1, Kestutis Kveraga1,2; 1Massachusetts General Hospital, 2Harvard Medical School, 3The Pennsylvania State University
During face perception, we integrate facial expression and eye gaze to extract social messages from their shared signals. For example, fear with averted gaze provides a congruent avoidance cue, signaling both threat presence and its location, whereas fear with direct gaze sends an incongruent cue, leaving threat location ambiguous. It has been proposed that these cues are processed via two distinct pathways: reflexive processing of clear threat cues via the magnocellular pathway and reflective processing of ambiguous threat cues via the parvocellular pathway. Because growing evidence has identified a variety of sex differences in affective perception, we investigated whether threat cues presented to these pathways evoked different behavioral and neural responses in females vs. males. We adjusted luminance and color of face stimuli to selectively engage magnocellular or parvocellular processing and asked observers (N=108) to identify facial expression (neutral vs. fear). Females were more accurate to faces with averted gaze and showed greater left amygdala reactivity both to fearful and neutral faces. Conversely, males showed greater right amygdala activation only for averted-gaze fear (clear threat) faces presented as magnocellular-biased stimuli. Furthermore, females had greater bilateral amygdala volumes, which positively correlated with accuracy for magnocellular-biased fear, whereas males showed a similar positive correlation only for the right amygdala volume. Our findings suggest that magnocellular and parvocellular processing of facial threat cues is modulated by functional and structural differences in the amygdalae associated with observers’ sex, with bilateral processing in women and more right-lateralized processing in men.
Topic Area: EMOTION & SOCIAL: Person perception