The neural correlates of early identity and expression processing

• Main Author: Rothstein, Pia
• Published: University College London (University of London) 2006
• Subjects: 152.14
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.430739

Faces are probably one of the most important objects that we encounter in that they convey multi-layered and intertwined information such as identity, intentionality and emotional expression. Thus, it is not surprising that understanding a face has been the focus of intense multi-disciplinary research over the last decades. An influential framework for face processing was suggested by Bruce and Young (1986). Based on this model I tested three hypotheses: the first relates to the hierarchical structure of face processing the second relates to the nature of early face processing and the third relates to a possible early route for expression processing. The hierarchical nature of identity processing was tested using fMRI and behavioural experiments. These studies suggested three stages for face identity processing: the first involves representation of physical properties of a face in posterior occipital cortices the second reflects categorical representation of identity in fusiform gyrus the third represents facial identity processing that depends on familiarity with a face and involves anterior temporal polar cortices. Focusing on the first stage of the hierarchical processing of a face, I suggest that in early identity processing different types of information from of a face are processed separately. Two dissociations are observed in posterior occipital cortices, the first between processing different bands of spatial frequency information and the second between processing feature and configural information. In addition, I demonstrated that featural information is important for individuating faces and sensitivity to configural information is predictive of general face recognition skill. Evidence for early processing of expression information that is mediated via amygdala is demonstrated in a patient study. Patients and healthy controls with intact amygdalae differed from patients with amygdale lesions in an early ERP and fMRI responses to fearful expressions.