title: Repetitive Transcorneal Alternating Current Stimulation Reduces Brain Idling State After Long-term Vision Loss.
abstract: BACKGROUND
  Deafferentation of visual system structures following brain or optic nerve injury leaves cortical areas deprived of visual input. Deprived cortical areas have a reduced sensory information processing and are characterized with localized enhanced or synchronized rhythms believed to represent an "idling state".
  
  
  OBJECTIVE
  We hypothesized that cortical idling can be modified with transcorneal alternating current stimulation (tACS) known to modulate cortical oscillations and thus change the functional state of the deafferented areas.
  
  
  METHODS
  tACS was applied in rat model of severe optic nerve crush using a protocol similar to our clinical studies (200 μA, 2-8 Hz) for 5 treatment days right after the lesion and at the chronic stage (3 months later). EEG and VEP were recorded over the visual cortices. In vivo confocal neuroimaging of the retina and histology of the optic nerves were performed.
  
  
  RESULTS
  Morphological investigations showed massive retinal ganglion cells death and degeneration of the optic nerves after crush. Visual loss was associated with increased EEG spectral power and lower coherence, indicating an "idling state". Stimulation induced a significant decrease of EEG power towards normal values. These effects were especially pronounced in the chronic stage.
  
  
  CONCLUSIONS
  Our results suggest that alternating current injected via the eye is able to modulate visually deprived brain areas and thus reduce cortical idling.
authors.affiliation: Otto-von-Guericke University of Magdeburg, Medical Faculty, Institute of Medical Psychology, Magdeburg, Germany. Electronic address: elenagen.sergeeva@gmail.com.
authors.forename: E G
authors.initials: EG
authors.lastname: Sergeeva
authors.affiliation: Otto-von-Guericke University of Magdeburg, Medical Faculty, Institute of Medical Psychology, Magdeburg, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Bola
authors.affiliation: Otto-von-Guericke University of Magdeburg, Medical Faculty, Institute of Medical Psychology, Magdeburg, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Wagner
authors.affiliation: Otto-von-Guericke University of Magdeburg, Medical Faculty, Institute of Medical Psychology, Magdeburg, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Lazik
authors.affiliation: Otto-von-Guericke University of Magdeburg, Medical Faculty, Institute of Medical Psychology, Magdeburg, Germany.
authors.forename: N
authors.initials: N
authors.lastname: Voigt
authors.affiliation: Otto-von-Guericke University of Magdeburg, Medical Faculty, Institute of Neuropathology, Leipziger Str. 44, 39120 Magdeburg, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Mawrin
authors.affiliation: Institute of Psychology, Russian Academy of Science, Moscow, Russia.
authors.forename: A G
authors.initials: AG
authors.lastname: Gorkin
authors.affiliation: Nencki Institute of Experimental Biology, Warsaw, Poland.
authors.forename: W J
authors.initials: WJ
authors.lastname: Waleszczyk
authors.affiliation: Otto-von-Guericke University of Magdeburg, Medical Faculty, Institute of Medical Psychology, Magdeburg, Germany.
authors.forename: B A
authors.initials: BA
authors.lastname: Sabel
authors.affiliation: Otto-von-Guericke University of Magdeburg, Medical Faculty, Institute of Medical Psychology, Magdeburg, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Henrich-Noack
mesh_terms: D000818:Animals; D001766:Blindness / Q000209:etiology / Q000503:physiopathology / Q000628:therapy*; D001921:Brain / Q000502:physiology*; D003315:Cornea / Q000502:physiology*; D004599:Electric Stimulation Therapy / Q000379:methods*; D005074:Evoked Potentials, Visual / Q000502:physiology; D008297:Male; D009409:Nerve Crush / Q000379:methods; D059906:Neuroimaging; D020221:Optic Nerve Injuries / Q000150:complications / Q000503:physiopathology / Q000628:therapy; D051381:Rats; D013997:Time Factors; D014793:Visual Cortex / Q000502:physiology
keywords: Alternating current stimulation; Brain state; EEG; Non-invasive brain stimulation; Optic nerve crush; Vision restoration; Visual cortex