Brain network dynamics are hierarchically organized in time

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 114; no. 48; pp. 12827 - 12832
• Main Authors: Vidaurre, Diego, Smith, Stephen M., Woolrich, Mark W.
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 28.11.2017
• Series: From the Cover
• Subjects: Adult; Biological Sciences; Brain; Brain - anatomy & histology; Brain - diagnostic imaging; Brain - physiology; Brain Mapping; Cognition & reasoning; Cognition - physiology; Female; Humans; Magnetic Resonance Imaging; Male; Metastasis; Models, Neurological; Nerve Net - anatomy & histology; Nerve Net - diagnostic imaging; Nerve Net - physiology; Neural Pathways - anatomy & histology; Neural Pathways - diagnostic imaging; Neural Pathways - physiology; NMR; Nuclear magnetic resonance; Quantitative Trait, Heritable; Rest - physiology; Task Performance and Analysis; Time Factors; metastates; dynamic functional connectivity; hidden Markov model; resting-state networks
• ISSN: 0027-8424; 1091-6490; 1091-6490
• DOI: 10.1073/pnas.1705120114

The brain recruits neuronal populations in a temporally coordinated manner in task and at rest. However, the extent to which large-scale networks exhibit their own organized temporal dynamics is unclear. We use an approach designed to find repeating network patterns in whole-brain resting fMRI data, where networks are defined as graphs of interacting brain areas. We find that the transitions between networks are nonrandom, with certain networks more likely to occur after others. Further, this nonrandom sequencing is itself hierarchically organized, revealing two distinct sets of networks, or metastates, that the brain has a tendency to cycle within. One metastate is associated with sensory and motor regions, and the other involves areas related to higher order cognition. Moreover, we find that the proportion of time that a subject spends in each brain network and metastate is a consistent subject-specific measure, is heritable, and shows a significant relationship with cognitive traits.