title: Changes in resting state effective connectivity in the motor network following rehabilitation of upper extremity poststroke paresis.
abstract: BACKGROUND
  A promising paradigm in human neuroimaging is the study of slow (<0.1 Hz) spontaneous fluctuations in the hemodynamic response measured by functional magnetic resonance imaging (fMRI). Spontaneous activity (i.e., resting state) refers to activity that cannot be attributed to specific inputs or outputs, that is, activity intrinsically generated by the brain.
  
  
  METHODS
  This article presents pilot data examining neural connectivity in patients with poststroke hemiparesis before and after 3 weeks of upper extremity rehabilitation in the Accelerated Skill Acquisition Program (ASAP). Resting-state fMRI data acquired pre and post therapy were analyzed using an exploratory adaptation of structural equation modeling (SEM) to evaluate therapy-related changes in motor network effective connectivity.
  
  
  RESULTS
  Each ASAP patient showed behavioral improvement. ASAP patients also showed increased influence of the affected hemisphere premotor cortex (a-PM) upon the unaffected hemisphere premotor cortex (u-PM) following therapy. The influence of a-PM on affected hemisphere primary motor cortex (a-M1) also increased with therapy for 3 of 5 patients, including those with greatest behavioral improvement.
  
  
  CONCLUSIONS
  Our findings suggest that network analyses of resting-state fMRI constitute promising tools for functional characterization of functional brain disorders, for intergroup comparisons, and potentially for assessing effective connectivity within single subjects; all of which have important implications for stroke rehabilitation.
authors.affiliation: Wallace H. Coulter Department of Biomedical Engineering, Emory University and the Georgia Institute of Technology, Atlanta, USA.
authors.forename: G Andrew
authors.initials: GA
authors.lastname: James
authors.forename: Zhong-Lin
authors.initials: ZL
authors.lastname: Lu
authors.forename: John W
authors.initials: JW
authors.lastname: VanMeter
authors.forename: K
authors.initials: K
authors.lastname: Sathian
authors.forename: Xiaoping P
authors.initials: XP
authors.lastname: Hu
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Butler
mesh_terms: D000368:Aged; D001132:Arm; D004525:Efferent Pathways / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology; D010291:Paresis / Q000209:etiology / Q000503:physiopathology* / Q000534:rehabilitation*; D010865:Pilot Projects; D020127:Recovery of Function; D012146:Rest / Q000502:physiology*; D020521:Stroke / Q000473:pathology / Q000503:physiopathology*; D000071939:Stroke Rehabilitation