title: Hypoperfusion without stroke alters motor activation in the opposite hemisphere.
abstract: To specifically investigate the effect that large-vessel disease may have on cortical reorganization, we used functional magnetic resonance imaging to study patients with unilateral hemispheric hypoperfusion and impaired vasomotor reactivity from critical internal carotid or middle cerebral artery disease but without stroke. We hypothesized that when these patients used the hand contralateral to the hypoperfused hemisphere they would show unique activation in motor-related areas of the normally perfused hemisphere, that is, ipsilateral activation. We found that normal performance of two motor tasks was associated with increased ipsilateral hemispheric activation in the patients compared with age-matched controls. In addition, although task difficulty had an effect on ipsilateral activation, the increased ipsilateral activation seen in patients was not dependent on task difficulty. Our findings demonstrate that hemodynamic compromise alone is sufficient to cause atypical ipsilateral activation. This activation may serve to maintain normal motor performance.
authors.affiliation: Department of Neurology, Taub Institute, Columbia University, New York, New York, USA. jwk18@columbia.edu
authors.forename: John W
authors.initials: JW
authors.lastname: Krakauer
authors.forename: Petya D
authors.initials: PD
authors.lastname: Radoeva
authors.forename: Eric
authors.initials: E
authors.lastname: Zarahn
authors.forename: Jennifer
authors.initials: J
authors.lastname: Wydra
authors.forename: Ronald M
authors.initials: RM
authors.lastname: Lazar
authors.forename: Joy
authors.initials: J
authors.lastname: Hirsch
authors.forename: Randolph S
authors.initials: RS
authors.lastname: Marshall
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002561:Cerebrovascular Disorders / Q000378:metabolism / Q000503:physiopathology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008875:Middle Aged; D009044:Motor Cortex / Q000502:physiology*; D009048:Motor Skills / Q000502:physiology*; D020521:Stroke / Q000378:metabolism / Q000503:physiopathology