Abstract
Previous research has identified a network of cortical areas reliably engaged when perceiving and thinking about other people – the so-called core and extended face-perception systems. These regions have been extensively studied over the past two decades but a systematic study of the dynamical changes of this system across varied tasks has been lacking. Here, in a block design fMRI experiment, healthy volunteers (N=20) were presented with highly familiar faces and asked to recall person-specific semantic information (roughly grouped into nominal, physical, social, episodic and factual information - 10 experimental conditions total). Response profiles were collected from independently localised face selective brain regions. Examining cognitive activation in context permitted a fuller understanding of regional contribution. For instance, while the ATL is engaged in nominal knowledge compared to control, relative to the other cognitive domains ATL is comparatively deactivated, in contradistinction to previous findings. Rather the ATL shows tuning for social cognition. Instead the IFG was weighted more more strongly towards nominal tasks. By applying network-level Representational Similarity Analysis (netRSA) we identified three collections of regions with the biggest pattern similarity, forming three distinct functional sub-units: 1) Precuneus, mPFC, pSTSs and ATLs. 2): Occipital and fusiform face areas together with orbital and inferior-frontal gyri, 3) Anterior face patches and the amygdalae [validated via bootstrapping]. Examining brain responses in context of a range of tasks enables fuller inferences to be made about regional tuning. Furthermore, netRSA reveals systems-level organization into functional processing units that coordinate to address different task demands. Core regions form transient functional relationships with frontal regions possibly reflecting top-down control. Regions associated with default mode preserve their relationship during task and jointly support episodic, semantic and social person-related cognition but physical and nominal cognition to a much lesser extent.
Meeting abstract presented at VSS 2017