Ipsilateral motor activation during unimanual and bimanual motor tasks

Academic Article


  • Objective: To test for the presence and possible asymmetry of ipsilateral motor activation during unimanual and bimanual motor tasks. Methods: Twelve right-handed healthy subjects underwent motor evoked potential (MEP) measurement of one hand (target-hand) while the other hand (task-hand) performed different motor tasks. The target-hand was either at rest (first experiment) or performed a Perdue PegBoard task (second experiment). The task-hand was either at rest, performed a simultaneous pegboard task, or rotated a coin (second experiment). Results: In the first experiment, the motor task resulted in significant increase in MEP area in the target-hand, regardless which hand was the task-hand, with a greater increase when the left hand was the task-hand. In the second experiment, ipsilateral motor activation was not present for either hand, however, when the right hand was the task-hand, performance of continuous coin rotation by the right hand resulted in a significant decrease in the MEP area of the left hand. Conclusions: Hemispheric asymmetry and task-dependence of ipsilateral motor cortex activation supports the postulate that motor activity may start bilaterally with subsequent interhemispheric inhibition. Furthermore, in right-handers, the left motor cortex is either more active in ipsilateral hand movements or exerts more effective inhibitory control over the right motor cortex than vice versa. Significance: We suggest that hemispheric asymmetry in ipsilateral motor control is a factor in determining motor dominance in right-handed individuals. © 2006 International Federation of Clinical Neurophysiology.
  • Authors

    Digital Object Identifier (doi)

    Author List

  • Ghacibeh GA; Mirpuri R; Drago V; Jeong Y; Heilman KM; Triggs WJ
  • Start Page

  • 325
  • End Page

  • 332
  • Volume

  • 118
  • Issue

  • 2