title: Reorganization of functional connectivity as a correlate of cognitive recovery in acquired brain injury.
abstract: Cognitive processes require a functional interaction between specialized multiple, local and remote brain regions. Although these interactions can be strongly altered by an acquired brain injury, brain plasticity allows network reorganization to be principally responsible for recovery. The present work evaluates the impact of brain injury on functional connectivity patterns. Networks were calculated from resting-state magnetoencephalographic recordings from 15 brain injured patients and 14 healthy controls by means of wavelet coherence in standard frequency bands. We compared the parameters defining the network, such as number and strength of interactions as well as their topology, in controls and patients for two conditions: following a traumatic brain injury and after a rehabilitation treatment. A loss of delta- and theta-based connectivity and conversely an increase in alpha- and beta-band-based connectivity were found. Furthermore, connectivity parameters approached controls in all frequency bands, especially in slow-wave bands. A correlation between network reorganization and cognitive recovery was found: the reduction of delta-band-based connections and the increment of those based on alpha band correlated with Verbal Fluency scores, as well as Perceptual Organization and Working Memory Indexes, respectively. Additionally, changes in connectivity values based on theta and beta bands correlated with the Patient Competency Rating Scale. The current study provides new evidence of the neurophysiological mechanisms underlying neuronal plasticity processes after brain injury, and suggests that these changes are related with observed changes at the behavioural level.
authors.affiliation: Laboratory of Cognitive and Computational Neuroscience, Centre for Biomedical Technology, Universidad Politécnica de Madrid, Spain. nazareth@pluri.ucm.es
authors.forename: Nazareth P
authors.initials: NP
authors.lastname: Castellanos
authors.forename: Nuria
authors.initials: N
authors.lastname: Paúl
authors.forename: Victoria E
authors.initials: VE
authors.lastname: Ordóñez
authors.forename: Olivier
authors.initials: O
authors.lastname: Demuynck
authors.forename: Ricardo
authors.initials: R
authors.lastname: Bajo
authors.forename: Pablo
authors.initials: P
authors.lastname: Campo
authors.forename: Alvaro
authors.initials: A
authors.lastname: Bilbao
authors.forename: Tomás
authors.initials: T
authors.lastname: Ortiz
authors.forename: Francisco
authors.initials: F
authors.lastname: del-Pozo
authors.forename: Fernando
authors.initials: F
authors.lastname: Maestú
mesh_terms: D000293:Adolescent; D000328:Adult; D001921:Brain / Q000503:physiopathology*; D001930:Brain Injuries / Q000150:complications / Q000503:physiopathology* / Q000534:rehabilitation; D016022:Case-Control Studies; D003072:Cognition Disorders / Q000150:complications / Q000503:physiopathology* / Q000534:rehabilitation; D005260:Female; D006801:Humans; D015225:Magnetoencephalography; D008297:Male; D008875:Middle Aged; D009434:Neural Pathways / Q000503:physiopathology; D009473:Neuronal Plasticity; D009483:Neuropsychological Tests; D020127:Recovery of Function / Q000502:physiology*; D012146:Rest; D012815:Signal Processing, Computer-Assisted; D016896:Treatment Outcome; D055815:Young Adult