Abstract
Individuality, the uniqueness that distinguishes one person from another, may manifest as diverse rearrangements of functional connectivity during heterogeneous cognitive demands; yet, the neurobiological substrates of individuality, reflected in inter-individual variations of large-scale functional connectivity, have not been fully evidenced. Accordingly, we explored inter-individual variations of functional connectivity dynamics, subnetwork patterns and modular architecture while subjects watched identical video clips designed to induce different arousal levels. How inter-individual variations are manifested in the functional brain networks was examined with respect to four contrasting divisions: edges within the anterior versus posterior part of the brain, edges with versus without corresponding anatomically-defined structural pathways, inter- versus intra-module connections, and rich club edge types. Inter-subject variation in dynamic functional connectivity occurred to a greater degree within edges localized to anterior rather than posterior brain regions, without adhering to structural connectivity, between modules as opposed to within modules, and in weak-tie local edges rather than strong-tie rich-club edges. Arousal level significantly modulates inter-subject variability in functional connectivity, edge patterns, and modularity, and particularly enhances the synchrony of rich-club edges. These results imply that individuality resides in the dynamic reconfiguration of large-scale brain networks in response to a stream of cognitive demands.
Highlights
Data-driven biomarker for localizing brain regions of high inter-individual similarity or variations
Unlike previous studies, which limited their examinations of inter-subject variability to assessing asynchrony of regional activation across individuals, we focused on inter-regional functional connectivity at each edge and patterns of edge sets involved in a perceptual task
We evaluated the temporal synchronies of nodal activity and functional connectivity using temporal inter-subject correlations (ISC) of blood oxygenation level dependent signal (BOLD) changes
Summary
Data-driven biomarker for localizing brain regions of high inter-individual similarity or variations. Unlike previous studies, which limited their examinations of inter-subject variability to assessing asynchrony of regional activation across individuals, we focused on inter-regional functional connectivity at each edge (edge strength) and patterns of edge sets (subnetwork architecture) involved in a perceptual task. We detailed inter-subject variability with respect to five aspects of functional connectivity: connectivity within the anterior versus posterior areas of the brain, existence of underlying structural connectivity, intra- versus inter-modular connectivity, connectivity types in reference to the rich club organization schema and interactions between these four contrasts and arousal levels. Similar to previous studies[9,19], we compared connectivity in the anterior brain areas, the regions generally responsible for higher order cognitions, to posterior brain areas, the structures essential for sensory/early level processing
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