Abstract
The ability to perceive facial expressions of emotion is essential for effective social communication. However, the way that facial expression is represented in the brain remains controversial. Opposing models have proposed that the perception of facial expression is based on either a continuous or a categorical representation. In this study, we explored whether patterns of neural response in face-selective regions had continuous or categorical properties. Twenty-nine participants viewed images of facial expressions of five basic emotions (fear, anger, disgust, sad, happiness) in a fMRI block design. Face-selective regions were defined using an independent localizer scan. Patterns of response to different facial expressions were analysed using correlation based MVPA. To determine whether the patterns of response in face-selective regions involved continuous or categorical representation of facial expression, we compared the neural patterns of response with the pattern of behavioural response on tasks which involved either categorical or continuous perceptual judgements. The patterns of behavioural response from the continuous and categorical tasks were used as predictors in a multiple regression analysis. We found that the response to different facial expressions across all face-selective regions considered together was best fitted by a continuous rather than a categorical representation. However, when we explored the pattern of response in different subdivisions of the face-selective network it was clear that some regions (e.g. superior temporal) had a more continuous pattern of response to facial expressions, whereas other regions (e.g. inferior frontal) had a more categorical response. These results offer a novel demonstration that both continuous and categorical representations of facial expression underlie our ability to extract this important social cue.
Meeting abstract presented at VSS 2014