Neural response to specific components of fearful faces in healthy and schizophrenic adults

Perception of fearful faces is associated with functional activation of cortico-limbic structures, which has been found altered in individuals with psychiatric disorders such as schizophrenia, autism and major depression. The objective of this study was to isolate the brain response to the features of standardized fearful faces by incorporating principal component analysis (PCA) into the analysis of neuroimaging data of healthy volunteers and individuals with schizophrenia. At the first stage, the visual characteristics of morphed fearful facial expressions (FEEST, Young et al., 2002) were classified with PCA, which produced seven orthogonal factors, with some of them related to emotionally salient facial features (eyes, mouth, brows) and others reflecting non-salient facial features. Subsequently, these PCA-based factors were included into the functional magnetic resonance imaging (fMRI) analysis of 63 healthy volunteers and 32 individuals with schizophrenia performing a task that involved implicit processing of FEEST stimuli. In healthy volunteers, significant neural response was found to visual characteristics of eyes, mouth or brows. In individuals with schizophrenia, PCA-based analysis enabled us to identify several significant clusters of activation that were not detected by the standard approach. These clusters were implicated in processing of visual and emotional information and were attributable to the perception of eyes and brows. PCA-based analysis could be useful in isolating brain response to salient facial features in psychiatric populations.