High-level representations in human occipito-temporal cortex are indexed by distal connectivity

Abstract

Human object recognition is dependent on occipito-temporal cortex, but a complete understanding of the complex functional architecture of this area must account for how it is connected to the wider brain. Converging functional magnetic resonance imaging evidence shows that univariate responses to different categories of information (e.g. faces, bodies, & non-human objects) are strongly related to, and potentially shaped by, functional and structural connectivity to the wider brain. However, to date, there have been no systematic attempts to determine how distal connectivity and complex local high-level responses in occipito-temporal cortex (i.e. multivoxel response patterns) are related. Here, we show that distal functional connectivity is related to, and can reliably index, high-level representations for several visual categories (i.e. tools, faces, & places) within occipito-temporal cortex; that is, voxels sets that are strongly connected to distal brain areas show higher pattern discriminability than less well-connected sets do. We further show that, in several cases, pattern discriminability is higher in sets of well-connected voxels than sets defined by local activation (e.g. strong amplitude responses to faces in fusiform face area). Together, these findings demonstrate the important relationship between the complex functional organization of occipito-temporal cortex and wider brain connectivity. Significance statementHuman object recognition relies strongly on occipito-temporal cortex (OTC), yet responses in this broad area are often considered in relative isolation to the rest of the brain. We employ a novel connectivity-guided voxel selection approach with functional MRI data to show higher sensitivity to information (i.e. higher multivoxel pattern discriminability) in voxel sets that share strong connectivity to distal brain areas, relative to: 1) voxel sets that are less-strongly connected; and in several cases 2) voxel sets that are defined by strong local response amplitude. These findings underscore the importance of distal contributions to local processing in OTC.