BibTeX
@MISC{Torres_researchnew,
author = {Elizabeth B Torres},
title = {Research New symmetry of intended curved reaches},
year = {}
}
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Abstract
Background: Movement regularities are inherently present in automated goal-directed motions of the primate's arm system. They can provide important signatures of intentional behaviours driven by sensory-motor strategies, but it remains unknown if during motor learning new regularities can be uncovered despite high variability in the temporal dynamics of the hand motions. Methods: We investigated the conservation and violation of new movement regularity obtained from the hand motions traced by two untrained monkeys as they learned to reach outwardly towards spatial targets while avoiding obstacles in the dark. The regularity pertains to the transformation from postural to hand paths that aim at visual goals. Results: In length-minimizing curves the area enclosed between the Euclidean straight line and the curve up to its point of maximum curvature is 1/2 of the total area. Similar trend is found if one examines the perimeter. This new movement regularity remained robust to striking changes in arm dynamics that gave rise to changes in the speed of the reach, to changes in the hand path curvature, and to changes in the arm's postural paths. The area and perimeter ratios characterizing the regularity co-varied across repeats of randomly presented targets whenever the transformation from posture to hand paths was compliant with the intended goals. To interpret this conservation and the cases in which the regularity was violated and recovered, we provide a geometric model that characterizes arm-tohand
Keyphrases
curved reach research new symmetry new movement regularity hand motion hand path total area hand path curvature length-minimizing curve automated goal-directed motion arm system high variability towards spatial target visual goal arm dynamic similar trend movement regularity geometric model intentional behaviour intended goal important signature perimeter ratio sensory-motor strategy postural path untrained monkey maximum curvature temporal dynamic new regularity
