title: Brain functional connectivity network breakdown and restoration in blindness.
abstract: OBJECTIVE
  To characterize brain functional connectivity in subjects with prechiasmatic visual system damage and relate functional connectivity features to extent of vision loss.
  
  
  METHODS
  In this case-control study, resting-state, eyes-closed EEG activity was recorded in patients with partial optic nerve damage (n = 15) and uninjured controls (n = 13). We analyzed power density and functional connectivity (coherence, Granger causality), the latter as (1) between-areal coupling strength and (2) individually thresholded binary graphs. Functional connectivity was then modulated by noninvasive repetitive transorbital alternating current stimulation (rtACS; 10 days, 40 minutes daily; n = 7; sham, n = 8) to study how this would affect connectivity networks and perception.
  
  
  RESULTS
  Patients exhibited lower spectral power (p = 0.005), decreased short- (p = 0.015) and long-range (p = 0.033) coherence, and less densely clustered coherence networks (p = 0.025) in the high-alpha frequency band (11-13 Hz). rtACS strengthened short- (p = 0.003) and long-range (p = 0.032) alpha coherence and this was correlated with improved detection abilities (r = 0.57, p = 0.035) and processing speed (r = 0.56, p = 0.049), respectively.
  
  
  CONCLUSIONS
  Vision loss in the blind is caused not only by primary tissue damage but also by a breakdown of synchronization in brain networks. Because visual field improvements are associated with resynchronization of alpha band coherence, brain connectivity is a key component in partial blindness and in restoration of vision.
authors.affiliation: From the Institute of Medical Psychology (M.B., C.G., A.F., B.A.S.), Department of Computer Science (C.M.), and Department of Neurology (H.H.), Otto-von-Guericke University of Magdeburg; Department of Behavioral Neurology (H.H.), Leibniz Institute for Neurobiology, Magdeburg; and German Center for Neurodegenerative Diseases (DZNE) (H.H.), Magdeburg, Germany.
authors.forename: Michał
authors.initials: M
authors.lastname: Bola
authors.affiliation: From the Institute of Medical Psychology (M.B., C.G., A.F., B.A.S.), Department of Computer Science (C.M.), and Department of Neurology (H.H.), Otto-von-Guericke University of Magdeburg; Department of Behavioral Neurology (H.H.), Leibniz Institute for Neurobiology, Magdeburg; and German Center for Neurodegenerative Diseases (DZNE) (H.H.), Magdeburg, Germany.
authors.forename: Carolin
authors.initials: C
authors.lastname: Gall
authors.affiliation: From the Institute of Medical Psychology (M.B., C.G., A.F., B.A.S.), Department of Computer Science (C.M.), and Department of Neurology (H.H.), Otto-von-Guericke University of Magdeburg; Department of Behavioral Neurology (H.H.), Leibniz Institute for Neurobiology, Magdeburg; and German Center for Neurodegenerative Diseases (DZNE) (H.H.), Magdeburg, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Moewes
authors.affiliation: From the Institute of Medical Psychology (M.B., C.G., A.F., B.A.S.), Department of Computer Science (C.M.), and Department of Neurology (H.H.), Otto-von-Guericke University of Magdeburg; Department of Behavioral Neurology (H.H.), Leibniz Institute for Neurobiology, Magdeburg; and German Center for Neurodegenerative Diseases (DZNE) (H.H.), Magdeburg, Germany.
authors.forename: Anton
authors.initials: A
authors.lastname: Fedorov
authors.affiliation: From the Institute of Medical Psychology (M.B., C.G., A.F., B.A.S.), Department of Computer Science (C.M.), and Department of Neurology (H.H.), Otto-von-Guericke University of Magdeburg; Department of Behavioral Neurology (H.H.), Leibniz Institute for Neurobiology, Magdeburg; and German Center for Neurodegenerative Diseases (DZNE) (H.H.), Magdeburg, Germany.
authors.forename: Hermann
authors.initials: H
authors.lastname: Hinrichs
authors.affiliation: From the Institute of Medical Psychology (M.B., C.G., A.F., B.A.S.), Department of Computer Science (C.M.), and Department of Neurology (H.H.), Otto-von-Guericke University of Magdeburg; Department of Behavioral Neurology (H.H.), Leibniz Institute for Neurobiology, Magdeburg; and German Center for Neurodegenerative Diseases (DZNE) (H.H.), Magdeburg, Germany. bernhard.sabel@med.ovgu.de.
authors.forename: Bernhard A
authors.initials: BA
authors.lastname: Sabel
mesh_terms: D000513:Alpha Rhythm / Q000502:physiology*; D001766:Blindness / Q000175:diagnosis / Q000503:physiopathology* / Q000628:therapy; D001921:Brain / Q000503:physiopathology*; D016022:Case-Control Studies; D004558:Electric Stimulation / Q000379:methods; D004599:Electric Stimulation Therapy / Q000379:methods; D004569:Electroencephalography / Q000379:methods; D006801:Humans; D009415:Nerve Net / Q000503:physiopathology*; D009901:Optic Nerve Diseases / Q000175:diagnosis / Q000503:physiopathology* / Q000628:therapy