The separate neural control of hand movements and contact forces
Abstract
To manipulate an object, we must simultaneously control the contact forces exerted on the object and the movements of our hand. Two alternative views for manipulation have been proposed: one in which motions and contact forces are represented and controlled by separate neural processes, and one in which motions and forces are controlled jointly, by a single process. To evaluate these alternatives, we designed three tasks in which subjects maintained a specified contact force while their hand was moved by a robotic manipulandum. The prescribed contact force and hand motions were selected in each task to induce the subject to attain one of three goals: (1) exerting a regulated contact force, (2) tracking the motion of the manipulandum, and (3) attaining both force and motion goals concurrently. By comparing subjects' performances in these three tasks, we found that behavior was captured by the summed actions of two independent control systems: one applying the desired force, and the other guiding the hand along the predicted path of the manipulandum. Furthermore, the application of transcranial magnetic stimulation impulses to the posterior parietal cortex selectively disrupted the control of motion but did not affect the regulation of static contact force. Together, these findings are consistent with the view that manipulation of objects is performed by independent brain control of hand motions and interaction forces.
Additional Information
© 2009 Society for Neuroscience. Received Nov. 26, 2008; revised Jan. 2, 2009; accepted Feb. 3, 2009. This work was supported by National Institutes of Health/National Institute of Neurological Disorders and Stroke Grants NS035673 and NS058300. We thank James Stinear, Jon Shemmel, and Gwyn Lewis for their discussions regarding TMS and Konrad Kording for helpful comments on this manuscript.Attached Files
Published - Chib2009p1332J_Neurosci.pdf
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Additional details
- PMCID
- PMC3462071
- Eprint ID
- 14380
- Resolver ID
- CaltechAUTHORS:20090609-122356193
- NS035673
- NIH
- NS058300
- NIH
- Created
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2009-08-18Created from EPrint's datestamp field
- Updated
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2021-11-08Created from EPrint's last_modified field