title: Cortical overlap of joint representations contributes to the loss of independent joint control following stroke.
abstract: The loss of independent joint control in the paretic upper limb is a cardinal sign of movement disorders following stroke. However, the underlying neural mechanisms for such a loss following stroke are still largely unknown. In order to investigate the possible contribution of altered sensorimotor cortical activity to the loss of independent joint control, we measured electroencephalographic (EEG) and torque signals during the generation of static shoulder/elbow torques. We found significant increases in the overlap of shoulder and elbow joint representations at the cortical level in stroke subjects as compared to control subjects. Linear regression results demonstrated significant associations between the cortical overlap of joint representations and the degree of the loss of independent joint control. Therefore, we conclude that an increased overlap of cortical representations for shoulder and elbow contributes to the expression of the loss of independent shoulder/elbow control of the paretic upper limb in chronic hemiparetic stroke survivors.
authors.affiliation: Department of Physical Therapy and Human Movement Sciences, Northwestern University, 645 N. Michigan Ave., Suite 1100, Chicago, IL 60611, USA. j-yao4@northwestern.edu
authors.forename: Jun
authors.initials: J
authors.lastname: Yao
authors.forename: Albert
authors.initials: A
authors.lastname: Chen
authors.forename: Carolina
authors.initials: C
authors.lastname: Carmona
authors.forename: Julius P A
authors.initials: JP
authors.lastname: Dewald
mesh_terms: D000368:Aged; D002540:Cerebral Cortex / Q000503:physiopathology*; D004551:Elbow Joint / Q000294:innervation / Q000502:physiology*; D004569:Electroencephalography / Q000379:methods; D005073:Evoked Potentials, Somatosensory; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009048:Motor Skills; D009119:Muscle Contraction; D018482:Muscle, Skeletal / Q000294:innervation / Q000503:physiopathology*; D012785:Shoulder Joint / Q000294:innervation / Q000503:physiopathology*; D020521:Stroke / Q000503:physiopathology*; D013647:Task Performance and Analysis; D019415:Torque