Abstract
The amygdala is thought to play a key role in modulating cognitive processes including the recognition, learning, and appraisal of emotionally-salient events, according to previous neuroimaging and lesion studies. What remains to be determined, however, is the amygdala’s role in the enhanced or biased perception of affectively-laden stimuli. Recently, Tsuchiya et al. (2009) reported that a patient with bilateral amygdala lesions showed intact rapid detection of fearful faces under interocular suppression. We have replicated and extended that finding using a large cohort of adult patients (n=27) who had undergone resections of either their left (n=12) or right (n=15) amygdala. We used the same paradigm as our previous study (Yang et al., 2007) in which upright and inverted faces of neutral, happy, or fearful expressions were pitted against a dynamic, high contrast, noise display that evoked potent interocular suppression. Observers performed a 4-alternative forced-choice discrimination task, quickly indicating the location of the face stimulus as it emerged from suppression. Replicating previous findings, we found that fearful faces broke suppression more quickly compared to neutral faces (t(36)=4, p<.001) and happy faces (t(36)=6.1, p<.001). Importantly, the pattern across emotion conditions was not significantly different between patients and 10 healthy age-matched controls (F(2,70)=0.05, p>.05). Neither were there significant differences in performance between left and right amygdala lesion patients (F(2,50)=0.5, p>.05) nor any significant correlations between the size of intact amygdala tissue and behavioral performance. Our results along those of Tsuchiya et al. (2009) and Peich et al. (2010) suggest that the amygdala is not essential for enhanced detection of fear-related visual stimuli.
Meeting abstract presented at VSS 2012