title: Mapping the functional connectome traits of levels of consciousness.
abstract: Examining task-free functional connectivity (FC) in the human brain offers insights on how spontaneous integration and segregation of information relate to human cognition, and how this organization may be altered in different conditions, and neurological disorders. This is particularly relevant for patients in disorders of consciousness (DOC) following severe acquired brain damage and coma, one of the most devastating conditions in modern medical care. We present a novel data-driven methodology, connICA, which implements Independent Component Analysis (ICA) for the extraction of robust independent FC patterns (FC-traits) from a set of individual functional connectomes, without imposing any a priori data stratification into groups. We here apply connICA to investigate associations between network traits derived from task-free FC and cognitive/clinical features that define levels of consciousness. Three main independent FC-traits were identified and linked to consciousness-related clinical features. The first one represents the functional configuration of a "resting" human brain, and it is associated to a sedative (sevoflurane), the overall effect of the pathology and the level of arousal. The second FC-trait reflects the disconnection of the visual and sensory-motor connectivity patterns. It also relates to the time since the insult and to the ability of communicating with the external environment. The third FC-trait isolates the connectivity pattern encompassing the fronto-parietal and the default-mode network areas as well as the interaction between left and right hemispheres, which are also associated to the awareness of the self and its surroundings. Each FC-trait represents a distinct functional process with a role in the degradation of conscious states of functional brain networks, shedding further light on the functional sub-circuits that get disrupted in severe brain-damage.
authors.affiliation: Coma Science Group, GIGA Research Center, University of Liège, Liège, Belgium; Department of Data-analysis, University of Ghent, B9000 Ghent, Belgium.
authors.forename: Enrico
authors.initials: E
authors.lastname: Amico
authors.affiliation: Department of Data-analysis, University of Ghent, B9000 Ghent, Belgium.
authors.forename: Daniele
authors.initials: D
authors.lastname: Marinazzo
authors.affiliation: Coma Science Group, GIGA Research Center, University of Liège, Liège, Belgium; University Hospital of Liège, Liège, Belgium.
authors.forename: Carol
authors.initials: C
authors.lastname: Di Perri
authors.affiliation: Coma Science Group, GIGA Research Center, University of Liège, Liège, Belgium; University Hospital of Liège, Liège, Belgium.
authors.forename: Lizette
authors.initials: L
authors.lastname: Heine
authors.affiliation: Coma Science Group, GIGA Research Center, University of Liège, Liège, Belgium; University Hospital of Liège, Liège, Belgium.
authors.forename: Jitka
authors.initials: J
authors.lastname: Annen
authors.affiliation: Coma Science Group, GIGA Research Center, University of Liège, Liège, Belgium; University Hospital of Liège, Liège, Belgium.
authors.forename: Charlotte
authors.initials: C
authors.lastname: Martial
authors.affiliation: Department of Neurology and Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA.
authors.forename: Mario
authors.initials: M
authors.lastname: Dzemidzic
authors.affiliation: University Hospital of Liège, Liège, Belgium.
authors.forename: Murielle
authors.initials: M
authors.lastname: Kirsch
authors.affiliation: University Hospital of Liège, Liège, Belgium.
authors.forename: Vincent
authors.initials: V
authors.lastname: Bonhomme
authors.affiliation: Coma Science Group, GIGA Research Center, University of Liège, Liège, Belgium; University Hospital of Liège, Liège, Belgium. Electronic address: steven.laureys@ulg.ac.be.
authors.forename: Steven
authors.initials: S
authors.lastname: Laureys
authors.affiliation: School of Industrial Engineering, Purdue University, West-Lafayette, IN, USA; Weldon School of Biomedical Engineering, Purdue University, West-Lafayette, IN, USA; Purdue Institute for Integrative Neuroscience, Purdue University, West-Lafayette, IN, USA. Electronic address: jgonicor@purdue.edu.
authors.forename: Joaquín
authors.initials: J
authors.lastname: Goñi
mesh_terms: D000328:Adult; D018685:Anesthetics, Inhalation / Q000494:pharmacology; D001143:Arousal / Q000187:drug effects; D001931:Brain Mapping / Q000379:methods*; D003071:Cognition / Q000502:physiology; D015331:Cohort Studies; D003243:Consciousness / Q000187:drug effects / Q000502:physiology*; D003244:Consciousness Disorders / Q000139:chemically induced / Q000000981:diagnostic imaging / Q000523:psychology*; D005260:Female; D005625:Frontal Lobe / Q000000981:diagnostic imaging / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008606:Mental Processes / Q000502:physiology; D008738:Methyl Ethers / Q000494:pharmacology; D008875:Middle Aged; D009434:Neural Pathways / Q000000981:diagnostic imaging / Q000187:drug effects / Q000502:physiology*; D010296:Parietal Lobe / Q000000981:diagnostic imaging / Q000502:physiology; D012677:Sensation / Q000187:drug effects; D000077149:Sevoflurane; D014796:Visual Perception / Q000187:drug effects
chemical_list: D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D000077149:Sevoflurane
keywords: Brain connectivity; Consciousness; Network science; fMRI