title: Time-dependent changes in cortical excitability after prolonged visual deprivation.
abstract: Transcranial magnetic stimulation applied to the occipital cortex can elicit phosphenes. Changes in the phosphene threshold provide a measure of visual cortex excitability. Phosphene threshold was measured in participants blindfolded for five consecutive days to assess the effects of prolonged visual deprivation on visual cortical excitability. After 48 h of blindfolding, an acute decrease in phosphene threshold was observed, followed by a significant increase by day 5. Phosphene threshold returned to preblindfold levels within 2 h of light re-exposure. Thus, light deprivation is characterized by a transient increase in visual cortical excitability, followed by a sustained decrease in visual cortex excitability that quickly returns to baseline levels after re-exposure to light.
authors.affiliation: Department of Neurology, Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA.
authors.forename: Naomi B
authors.initials: NB
authors.lastname: Pitskel
authors.forename: Lotfi B
authors.initials: LB
authors.lastname: Merabet
authors.forename: Ciro
authors.initials: C
authors.lastname: Ramos-Estebanez
authors.forename: Thomas
authors.initials: T
authors.lastname: Kauffman
authors.forename: Alvaro
authors.initials: A
authors.lastname: Pascual-Leone
mesh_terms: D000328:Adult; D001766:Blindness / Q000503:physiopathology; D015536:Down-Regulation / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D009433:Neural Inhibition / Q000502:physiology; D010719:Phosphenes / Q000502:physiology*; D010775:Photic Stimulation; D012683:Sensory Deprivation / Q000502:physiology*; D012684:Sensory Thresholds / Q000502:physiology*; D013995:Time; D013997:Time Factors; D050781:Transcranial Magnetic Stimulation; D014793:Visual Cortex / Q000502:physiology*; D014795:Visual Pathways / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*