title: Enhanced Effective Connectivity Between Primary Motor Cortex and Intraparietal Sulcus in Well-Recovered Stroke Patients.
abstract: OBJECTIVE
  Ischemic strokes with motor deficits lead to widespread changes in neural activity and interregional coupling between primary and secondary motor areas. Compared with frontal circuits, the knowledge is still limited to what extent parietal cortices and their interactions with frontal motor areas undergo plastic changes and might contribute to residual motor functioning after stroke.
  
  
  METHODS
  Fifteen well-recovered patients were evaluated 3 months after stroke by means of functional magnetic resonance imaging while performing visually guided hand grips with their paretic hand. Dynamic causal modeling was used to investigate task-related effective connectivity between ipsilesional posterior parietal regions along the intraparietal sulcus and frontal key motor areas, such as the primary motor cortex, the ventral premotor cortex, and the supplementary motor area.
  
  
  RESULTS
  Compared with healthy controls of similar age and sex, we observed significantly enhanced reciprocal facilitatory connectivity between the primary motor cortex and the anterior intraparietal sulcus of the ipsilesional hemisphere. Beyond that and as a fingerprint of excellent recovery, the coupling pattern of the parietofrontal network was near-normal. An association between coupling parameters and clinical scores was not detected.
  
  
  CONCLUSIONS
  The present analysis further adds to the understanding of the parietofrontal network of the ipsilesional hemisphere as a prominent circuit involved in plastic changes after stroke.
authors.affiliation: From the Department of Neurology (R.S., B.M.F., M.B., B.C., G.T., F.C.H., C.G.) and Department of Medical Biometry and Epidemiology (A.B.), University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Schulz
authors.affiliation: From the Department of Neurology (R.S., B.M.F., M.B., B.C., G.T., F.C.H., C.G.) and Department of Medical Biometry and Epidemiology (A.B.), University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Anika
authors.initials: A
authors.lastname: Buchholz
authors.affiliation: From the Department of Neurology (R.S., B.M.F., M.B., B.C., G.T., F.C.H., C.G.) and Department of Medical Biometry and Epidemiology (A.B.), University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Benedikt M
authors.initials: BM
authors.lastname: Frey
authors.affiliation: From the Department of Neurology (R.S., B.M.F., M.B., B.C., G.T., F.C.H., C.G.) and Department of Medical Biometry and Epidemiology (A.B.), University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Marlene
authors.initials: M
authors.lastname: Bönstrup
authors.affiliation: From the Department of Neurology (R.S., B.M.F., M.B., B.C., G.T., F.C.H., C.G.) and Department of Medical Biometry and Epidemiology (A.B.), University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Bastian
authors.initials: B
authors.lastname: Cheng
authors.affiliation: From the Department of Neurology (R.S., B.M.F., M.B., B.C., G.T., F.C.H., C.G.) and Department of Medical Biometry and Epidemiology (A.B.), University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Götz
authors.initials: G
authors.lastname: Thomalla
authors.affiliation: From the Department of Neurology (R.S., B.M.F., M.B., B.C., G.T., F.C.H., C.G.) and Department of Medical Biometry and Epidemiology (A.B.), University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Friedhelm C
authors.initials: FC
authors.lastname: Hummel
authors.affiliation: From the Department of Neurology (R.S., B.M.F., M.B., B.C., G.T., F.C.H., C.G.) and Department of Medical Biometry and Epidemiology (A.B.), University Medical Center Hamburg-Eppendorf, Hamburg, Germany. gerloff@uke.de.
authors.forename: Christian
authors.initials: C
authors.lastname: Gerloff
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D059907:Functional Neuroimaging; D018737:Hand Strength; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D008959:Models, Neurological; D009044:Motor Cortex / Q000503:physiopathology*; D009434:Neural Pathways / Q000503:physiopathology; D009473:Neuronal Plasticity / Q000502:physiology*; D010291:Paresis / Q000209:etiology / Q000503:physiopathology*; D010296:Parietal Lobe / Q000503:physiopathology*; D020127:Recovery of Function; D020521:Stroke / Q000150:complications / Q000503:physiopathology*
keywords: DCM; PPC; dynamic causal modeling; fMRI; stroke recovery