title: Spatial and temporal functional connectivity changes between resting and attentive states.
abstract: Remote brain regions show correlated spontaneous activity at rest within well described intrinsic connectivity networks (ICNs). Meta-analytic coactivation studies have uncovered networks similar to resting ICNs, suggesting that in task states connectivity modulations may occur principally within ICNs. However, it has also been suggested that specific "hub" regions dynamically link networks under different task conditions. Here, we used functional magnetic resonance imaging at rest and a continuous visual attention task in 16 participants to investigate whether a shift from rest to attention was reflected by within-network connectivity modulation, or changes in network topography. Our analyses revealed evidence for both modulation of connectivity within the default-mode (DMN) and dorsal attention networks (DAN) between conditions, and identified a set of regions including the temporoparietal junction (TPJ) and posterior middle frontal gyrus (MFG) that switched between the DMN and DAN depending on the task. We further investigated the temporal nonstationarity of flexible (TPJ and MFG) regions during both attention and rest. This showed that moment-to-moment differences in connectivity at rest mirrored the variation in connectivity between tasks. Task-dependent changes in functional connectivity of flexible regions may, therefore, be understood as shifts in the proportion of time specific connections are engaged, rather than a switch between networks per se. This ability of specific regions to dynamically link ICNs under different task conditions may play an important role in behavioral flexibility.
authors.affiliation: Department of Radiology, University of Calgary, Calgary, Alberta, Canada; Department of Psychiatry, University of Calgary, Calgary, Alberta, Canada; Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada; Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada; Child and Adolescent Imaging Research Program, Alberta Children's Hospital, Calgary, Alberta, Canada.
authors.forename: Signe
authors.initials: S
authors.lastname: Bray
authors.forename: Aiden E G F
authors.initials: AE
authors.lastname: Arnold
authors.forename: Richard M
authors.initials: RM
authors.lastname: Levy
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Iaria
mesh_terms: D000293:Adolescent; D000328:Adult; D001288:Attention / Q000502:physiology*; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009434:Neural Pathways / Q000502:physiology; D012146:Rest / Q000502:physiology*; D012815:Signal Processing, Computer-Assisted; D013997:Time Factors; D014796:Visual Perception / Q000502:physiology; D055815:Young Adult
keywords: attention; connectivity; hubs; networks; resting functional magnetic resonance imaging