(A) study on the negativity bias-related neural basis in facial emotion perception

Abstract

The recognition of emotional facial expressions is critical for our social interactions. Negativity bias in facial emotion processing, a tendency to interpret ambiguous facial expressions negatively, can be observed in healthy people depending on their mental states and more frequently reported among mood disorder patients. Especially, this negativity bias has been thought to be one of the important mechanisms of maintenance and aggravation of the anxiety disorder. However, the neural mechanisms underlying the negativity bias in facial emotion processing remain unclear. In this study, we proposed that increased representational similarity between neutral and negative emotional faces is a cause of the negativity bias during facial emotion perception. To test this hypothesis, we performed an event-related functional magnetic resonance imaging (fMRI) experiment. During the scan, the cortical activities were recorded while non-patient participants performed facial emotion recognition tasks with a series of graded stimuli morphed between prototypical neutral and angry or happy faces. We found that the participant with the higher negativity bias showed more similarities between the representations for prototypical neutral and angry faces in the right ventrolateral prefrontal cortex (VLPFC), one of the cortical areas whose response patterns could be used to decode prototypical angry and neutral faces. Moreover, the representation of the right VLPFC for low-intensity angry faces was more likely classified as the prototypical angry faces as the negativity bias increases. Additionally, these representational similarities were significantly correlated with individual state-anxiety level. Therefore, these results suggest that the negativity bias in facial emotion processing is specifically linked to the neural representation similarity between a perceived face and angry face in the right VLPFC.