Abstract
During face perception, we integrate facial expression and eye gaze to make social inferences from their combined signals. For example, a fearful face and averted eye gaze are both avoidance cues which indicate threat presence and its probable source, thus providing congruent, clear threat signal. Conversely, facial fear with direct gaze combines avoidance and approach cues, resulting in ambiguity about the threat source (Adams et al., 2012). We have shown (Im et al., 2017) that clear and ambiguous threat cues preferentially engage the magnocellular (M) and parvocellular (P) visual pathways, respectively. While aging is thought to degrade emotional perceptual abilities, its effects on threat cue processing in the M and P pathway processing are unknown. To fill this gap in knowledge, we scanned 108 participants ranging from 18 to 70 years old (65 females). We individually calibrated the luminance and color values of two-tone Mooney faces with direct or averted eye gaze to produce achromatic, < 8% luminance contrast (M) or isoluminant red/green (P) stimuli. The task was to identify the facial expression (neutral vs. fearful) as quickly and accurately as possible. Although older adults (OA, 41-70 years old) made slower responses than younger adults (YA, 18-40 years old), they remained as accurate as YA. In YA, we found greater left amygdala involvement in P-biased ambiguous threat cues and greater right amygdala involvement in M-biased clear threat cues. However, OA did not show such lateralized, pathway-specific attunement of the amygdalae. Furthermore, YA showed increased functional connectivity between the right amygdala and orbitofrontal cortex (OFC) for M-biased clear threat cues, and between the left amygdala and OFC for P-biased ambiguous threat cues. Together, our findings demonstrate that, compared to OA, YA showed greater pathway and hemispheric differentiation, and increased amygdala-OFC functional connectivity, while processing different types of compound threat cues.
Meeting abstract presented at VSS 2018