title: Monocular visual deprivation suppresses excitability in adult human visual cortex.
abstract: The adult visual cortex maintains a substantial potential for plasticity in response to a change in visual input. For instance, transcranial magnetic stimulation (TMS) studies have shown that binocular deprivation (BD) increases the cortical excitability for inducing phosphenes with TMS. Here, we employed TMS to trace plastic changes in adult visual cortex before, during, and after 48 h of monocular deprivation (MD) of the right dominant eye. In healthy adult volunteers, MD-induced changes in visual cortex excitability were probed with paired-pulse TMS applied to the left and right occipital cortex. Stimulus-response curves were constructed by recording the intensity of the reported phosphenes evoked in the contralateral visual field at range of TMS intensities. Phosphene measurements revealed that MD produced a rapid and robust decrease in cortical excitability relative to a control condition without MD. The cortical excitability returned to preinterventional baseline levels within 3 h after the end of MD. The results show that in contrast to the excitability increase in response to BD, MD acutely triggers a reversible decrease in visual cortical excitability. This shows that the pattern of visual deprivation has a substantial impact on experience-dependent plasticity of the human visual cortex.
authors.affiliation: Danish Research Center for Magnetic Resonance, Copenhagen University Hospital, Hvidovre 2650, Denmark.
authors.forename: Astrid Rosenstand
authors.initials: AR
authors.lastname: Lou
authors.forename: Kristoffer Hougaard
authors.initials: KH
authors.lastname: Madsen
authors.forename: Olaf Bjarne
authors.initials: OB
authors.lastname: Paulson
authors.forename: Hanne Olsen
authors.initials: HO
authors.lastname: Julian
authors.forename: Jan Ulrik
authors.initials: JU
authors.lastname: Prause
authors.forename: Hartwig Roman
authors.initials: HR
authors.lastname: Siebner
authors.forename: Troels Wesenberg
authors.initials: TW
authors.lastname: Kjaer
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D009473:Neuronal Plasticity / Q000502:physiology*; D010719:Phosphenes / Q000502:physiology*; D012683:Sensory Deprivation / Q000502:physiology*; D050781:Transcranial Magnetic Stimulation; D014793:Visual Cortex / Q000502:physiology*; D055815:Young Adult