title: Large-Scale Functional Brain Network Reorganization During Taoist Meditation.
abstract: Meditation induces a distinct and reversible mental state that provides insights into brain correlates of consciousness. We explored brain network changes related to meditation by graph theoretical analysis of resting-state functional magnetic resonance imaging data. Eighteen Taoist meditators with varying levels of expertise were scanned using a within-subjects counterbalanced design during resting and meditation states. State-related differences in network topology were measured globally and at the level of individual nodes and edges. Although measures of global network topology, such as small-worldness, were unchanged, meditation was characterized by an extensive and expertise-dependent reorganization of the hubs (highly connected nodes) and edges (functional connections). Areas of sensory cortex, especially the bilateral primary visual and auditory cortices, and the bilateral temporopolar areas, which had the highest degree (or connectivity) during the resting state, showed the biggest decrease during meditation. Conversely, bilateral thalamus and components of the default mode network, mainly the bilateral precuneus and posterior cingulate cortex, had low degree in the resting state but increased degree during meditation. Additionally, these changes in nodal degree were accompanied by reorganization of anatomical orientation of the edges. During meditation, long-distance longitudinal (antero-posterior) edges increased proportionally, whereas orthogonal long-distance transverse (right-left) edges connecting bilaterally homologous cortices decreased. Our findings suggest that transient changes in consciousness associated with meditation introduce convergent changes in the topological and spatial properties of brain functional networks, and the anatomical pattern of integration might be as important as the global level of integration when considering the network basis for human consciousness.
authors.affiliation: 1 Brain Mapping Unit and Behavioural and Clinical Neurosciences Institute, University of Cambridge, Cambridge, United Kingdom .|2 Department of Neurology, National Taiwan University Hospital , Taipei, Taiwan .
authors.forename: Tun
authors.initials: T
authors.lastname: Jao
authors.affiliation: 3 Interdisciplinary MRI/MRS Lab, Department of Electrical Engineering, National Taiwan University , Taipei, Taiwan .
authors.forename: Chia-Wei
authors.initials: CW
authors.lastname: Li
authors.affiliation: 1 Brain Mapping Unit and Behavioural and Clinical Neurosciences Institute, University of Cambridge, Cambridge, United Kingdom .
authors.forename: Petra E
authors.initials: PE
authors.lastname: Vértes
authors.affiliation: 4 Graduate Institute of Biomedical Engineering, National Central University , Taoyuan, Taiwan .
authors.forename: Changwei Wesley
authors.initials: CW
authors.lastname: Wu
authors.affiliation: 5 Centre National de la Recherche Scientifique, Grenoble Image Parole Signal Automatique , Grenoble, France .
authors.forename: Sophie
authors.initials: S
authors.lastname: Achard
authors.affiliation: 3 Interdisciplinary MRI/MRS Lab, Department of Electrical Engineering, National Taiwan University , Taipei, Taiwan .|6 Neurobiology and Cognitive Science Center, National Taiwan University , Taipei, Taiwan .
authors.forename: Chao-Hsien
authors.initials: CH
authors.lastname: Hsieh
authors.affiliation: 3 Interdisciplinary MRI/MRS Lab, Department of Electrical Engineering, National Taiwan University , Taipei, Taiwan .
authors.forename: Chien-Hui
authors.initials: CH
authors.lastname: Liou
authors.affiliation: 3 Interdisciplinary MRI/MRS Lab, Department of Electrical Engineering, National Taiwan University , Taipei, Taiwan .
authors.forename: Jyh-Horng
authors.initials: JH
authors.lastname: Chen
authors.affiliation: 1 Brain Mapping Unit and Behavioural and Clinical Neurosciences Institute, University of Cambridge, Cambridge, United Kingdom .|7 Alternative Discovery and Development , GlaxoSmithKline, Cambridge, United Kingdom .|8 Cambridgeshire and Peterborough NHS Foundation Trust , Cambridge, United Kingdom .
authors.forename: Edward T
authors.initials: ET
authors.lastname: Bullmore
mesh_terms: D000328:Adult; D000368:Aged; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping; D003243:Consciousness / Q000502:physiology; D005260:Female; D006179:Gyrus Cinguli / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D019122:Meditation / Q000523:psychology*; D008875:Middle Aged; D009415:Nerve Net / Q000502:physiology*; D009434:Neural Pathways / Q000502:physiology; D012146:Rest / Q000502:physiology*
keywords: brain networks; consciousness; fMRI; functional connectivity; meditation; network hubs; resting state