The functional effects of neuroplastic changes in visually-deprived sighted subjects.
Poster Presentation

Naomi Bass Pitskel
Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School

Thomas Kauffman
Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School

Erin Abrigo
Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School

Hugo Theoret
Departement de Psychologie and Hopital Sainte-Justine, Universite de Montreal

Alvaro Pascual-Leone
Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School

     Abstract ID Number: 170
     Full text: Not available
     Last modified: March 19, 2006
     Presentation date: 06/18/2006 4:00 PM in Hamilton Building, Foyer
     (View Schedule)

Abstract
Functional neuroimaging of visually-deprived sighted subjects shows occipital cortex activation during tactile discrimination tasks. Similar activation observed in early blind subjects has been shown to be functionally relevant in task performance. To determine whether this activation is also functionally relevant in visually-deprived sighted subjects, repetitive transcranial magnetic stimulation (rTMS) was used to disrupt performance in a Braille character discrimination task in blindfolded sighted subjects and sighted controls. Blindfolded subjects were blindfolded for the duration of 5 days, and all received intensive Braille training over the 5-day period. On day 5, 1-Hz rTMS to the occipital cortex did not affect task performance in sighted controls, but significantly impaired performance in visually-deprived subjects. This effect on performance disappeared by day 6, less than 24 hours after removal of the blindfold. The results indicate that the occipital cortex activation is causally related to the blindfolded subjects’ ability to read Braille. The disappearance of this effect by day 6 reveals a very rapid reversal of plastic changes. The rapid time course of this recruitment and its reversal is a testament to the dynamic nature of brain organization.