Visual Overview
Abstract
Suppose that someone bumps into your arm at a party while you are holding a glass of wine. Motion of the disturbed arm will engage rapid and goal-directed feedback responses in the upper-limb. Although such responses can rapidly counter the perturbation, it is also clearly desirable not to destabilize your grasp and/or spill the wine. Here we investigated how healthy humans maintain a stable grasp following perturbations by using a paradigm that requires spatial tuning of the motor response dependent on the location of a virtual target. Our results highlight a synchronized expression of target-directed feedback in shoulder and hand muscles occurring at ∼60 ms. Considering that conduction delays are longer for the more distal hand muscles, these results suggest that target-directed responses in hand muscles were initiated before those for the shoulder muscles. These results show that long-latency feedback can coordinate upper limb and hand muscles during object manipulation tasks.
Footnotes
↵1 S.H.S. is associated with BKIN Technologies that commercializes the robot that was used. The remaining authors declare no conflict of interest.
↵3 Fonds De La Recherche Scientifique-FNRS (Belgian National Fund for Scientific Research; 501100002661. We thank K. Moore, H. Bretzke, J. Peterson, and S. Hickman for technical and logistic support.
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