Compound facial threat cue perception: Contributions of visual pathways, aging, and anxiety

Abstract

Gaze direction and facial emotion can provide important cues about danger in the environment and are processed in what appears to be a functionally interactive and adaptive manner. Previous work has also revealed important individual differences in responses to compound threat cues. For instance, Individuals with high state anxiety showed increased amygdalar response to clear threat cues, while those with low anxiety were more sensitive to ambiguous threat cues (Ewbank et al., 2010). The effects of aging on the brain are another relevant factor to consider in this integrative process. In a large (N=131) fMRI study, we tested contributions of magnocellular (M) and parvocellular (P) pathways to threat cue integration, and examined how aging and anxiety influence processing. Participants (aged 18-71) viewed images of fearful or neutral faces with direct and averted gaze for one second presentations. These stimuli were presented in high luminance contrast (Unbiased), low luminance contrast (M-biased), or isoluminant red/green (P-biased) images. Overall, a clear threat cue (averted gaze fear) compared with a more ambiguous threat cue (averted gaze neutral) activated both amygdalae. We found that M-biased stimuli activated the right amygdala for ambiguous (fear with direct gaze) vs. clear (fear with averted gaze) threat cues. The older cohort (age greater than 50) showed greater activation in the amygdala and cortical face network to clear threat cues, while the younger cohort (age less than 40) had more overall activation to threat ambiguity. Further, right amygdala activity in the older cohort positively correlated (p 0.022) with state anxiety. Finally, high-anxiety subjects showed greater left amygdala activation to clear threat, while low-anxiety participants had increased bilateral amygdala activity to ambiguous threat. These findings suggest that perception of clear vs. ambiguous facial threat cues has different emphases in the M and P pathways, and interacts with perceivers' age and anxiety levels.

Meeting abstract presented at VSS 2016