title: Multi-voxel pattern analysis (MVPA) reveals abnormal fMRI activity in both the "core" and "extended" face network in congenital prosopagnosia.
abstract: The ability to identify faces is mediated by a network of cortical and subcortical brain regions in humans. It is still a matter of debate which regions represent the functional substrate of congenital prosopagnosia (CP), a condition characterized by a lifelong impairment in face recognition, and affecting around 2.5% of the general population. Here, we used functional Magnetic Resonance Imaging (fMRI) to measure neural responses to faces, objects, bodies, and body-parts in a group of seven CPs and ten healthy control participants. Using multi-voxel pattern analysis (MVPA) of the fMRI data we demonstrate that neural activity within the "core" (i.e., occipital face area and fusiform face area) and "extended" (i.e., anterior temporal cortex) face regions in CPs showed reduced discriminability between faces and objects. Reduced differentiation between faces and objects in CP was also seen in the right parahippocampal cortex. In contrast, discriminability between faces and bodies/body-parts and objects and bodies/body-parts across the ventral visual system was typical in CPs. In addition to MVPA analysis, we also ran traditional mass-univariate analysis, which failed to show any group differences in face and object discriminability. In sum, these findings demonstrate (i) face-object representations impairments in CP which encompass both the "core" and "extended" face regions, and (ii) superior power of MVPA in detecting group differences.
authors.affiliation: School of Psychology, University of East London London, UK ; Perception in Action Research Centre, and ARC Centre of Excellence in Cognition and its Disorders, Department of Cognitive Science, Faculty of Human Sciences, Macquarie University Sydney, NSW, Australia.
authors.forename: Davide
authors.initials: D
authors.lastname: Rivolta
authors.affiliation: Perception in Action Research Centre, and ARC Centre of Excellence in Cognition and its Disorders, Department of Cognitive Science, Faculty of Human Sciences, Macquarie University Sydney, NSW, Australia.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Woolgar
authors.affiliation: School of Psychology, and ARC Centre of Excellence in Cognition and its Disorders, University of Western Australia Crawley, WA, Australia.
authors.forename: Romina
authors.initials: R
authors.lastname: Palermo
authors.affiliation: Perception in Action Research Centre, and ARC Centre of Excellence in Cognition and its Disorders, Department of Cognitive Science, Faculty of Human Sciences, Macquarie University Sydney, NSW, Australia.
authors.forename: Marina
authors.initials: M
authors.lastname: Butko
authors.affiliation: Department of Family and Preventive Medicine, University of California San Diego La Jolla, CA, USA.
authors.forename: Laura
authors.initials: L
authors.lastname: Schmalzl
authors.affiliation: Perception in Action Research Centre, and ARC Centre of Excellence in Cognition and its Disorders, Department of Cognitive Science, Faculty of Human Sciences, Macquarie University Sydney, NSW, Australia.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Williams
keywords: MVPA; body perception; fMRI; face perception; multivariate analysis; object perception; prosopagnosia; unfamiliar face