title: Resting interhemispheric functional magnetic resonance imaging connectivity predicts performance after stroke.
abstract: OBJECTIVE
  Focal brain lesions can have important remote effects on the function of distant brain regions. The resulting network dysfunction may contribute significantly to behavioral deficits observed after stroke. This study investigates the behavioral significance of changes in the coherence of spontaneous activity in distributed networks after stroke by measuring resting state functional connectivity (FC) using functional magnetic resonance imaging.
  
  
  METHODS
  In acute stroke patients, we measured FC in a dorsal attention network and an arm somatomotor network, and determined the correlation of FC with performance obtained in a separate session on tests of attention and motor function. In particular, we compared the behavioral correlation with intrahemispheric FC to the behavioral correlation with interhemispheric FC.
  
  
  RESULTS
  In the attention network, disruption of interhemispheric FC was significantly correlated with abnormal detection of visual stimuli (Pearson r with field effect = -0.624, p = 0.002). In the somatomotor network, disruption of interhemispheric FC was significantly correlated with upper extremity impairment (Pearson r with contralesional Action Research Arm Test = 0.527, p = 0.036). In contrast, intrahemispheric FC within the normal or damaged hemispheres was not correlated with performance in either network. Quantitative lesion analysis demonstrated that our results could not be explained by structural damage alone.
  
  
  CONCLUSIONS
  These results suggest that lesions cause state changes in the spontaneous functional architecture of the brain, and constrain behavioral output. Clinically, these results validate using FC for assessing the health of brain networks, with implications for prognosis and recovery from stroke, and underscore the importance of interhemispheric interactions.
authors.affiliation: Department of Neurology, Washington University School of Medicine, 4525 Scott Avenue, St. Louis, MO 63110, USA.
authors.forename: Alex R
authors.initials: AR
authors.lastname: Carter
authors.forename: Serguei V
authors.initials: SV
authors.lastname: Astafiev
authors.forename: Catherine E
authors.initials: CE
authors.lastname: Lang
authors.forename: Lisa T
authors.initials: LT
authors.lastname: Connor
authors.forename: Jennifer
authors.initials: J
authors.lastname: Rengachary
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Strube
authors.forename: Daniel L W
authors.initials: DL
authors.lastname: Pope
authors.forename: Gordon L
authors.initials: GL
authors.lastname: Shulman
authors.forename: Maurizio
authors.initials: M
authors.lastname: Corbetta
mesh_terms: D000368:Aged; D001132:Arm / Q000294:innervation / Q000503:physiopathology; D001288:Attention / Q000502:physiology; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000473:pathology / Q000503:physiopathology*; D003072:Cognition Disorders / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology*; D004185:Disability Evaluation; D056344:Executive Function / Q000502:physiology; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009069:Movement Disorders / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology; D009415:Nerve Net / Q000473:pathology / Q000503:physiopathology; D009434:Neural Pathways / Q000473:pathology / Q000503:physiopathology; D009483:Neuropsychological Tests; D011237:Predictive Value of Tests; D011379:Prognosis; D011597:Psychomotor Performance / Q000502:physiology; D020521:Stroke / Q000150:complications* / Q000473:pathology / Q000503:physiopathology*