Generalization patterns during reach adaptation to target jump

Abstract

Event Abstract Back to Event Generalization patterns during reach adaptation to target jump Stephanie Westendorff1*, Bahareh Taghizadeh1 and Alexander Gail1 1 German Primate Center, Sensorimotor Group, BCCN Göttingen, Germany In typical visuomotor rotation tasks, adaptation is induced by a mismatch between visual and proprioceptive sensory input. Target-jump paradigms, i.e. tasks with sudden displacement of the movement target during movement initiation or execution, do not induce cross-modal mismatch, nor do they induce adaptation when subject are aware of the displacement. Here we present and characterize a novel target jump paradigm, in which reach movements reliably get adapted to target displacements. Subjects had to make center-out reaches to a peripheral target. Simultaneously they had to make a saccade to a neutral target. Saccadic suppression during the eye movement allowed us to displace the reach target during hand movement initiation or execution, without subjects noticing the perturbation. The reach target was displaced either to a different eccentricity (radial displacement) or to a different angular (directional displacement).Subjects incrementally adapted to the radial and to the directional displacement, with average learning rates similar to prism adaptation, and showed reliable negative aftereffects.We also tested the generalization of the adaptation effect to neighboring reach targets. Subjects were first adapted to either a radial or directional target displacement, and then probed at different positions along the radius and circumference of the adapted target. Preliminary analysis of our results suggests that movement endpoints to novel targets are off-set by a vector that is approximately equal to the displacement vector imposed on the adapted target. The offset decreases with increasing angular or radial distance from the adapted target.Our results show that reach adaptation in a target-jump experiment is possible when the displacement is obscured by a simultaneous saccade to a different target. The observed generalization patterns may be difficult to explain as a combination of independent adjustments on the direction and extent of movement. Consequently, our results may cast doubt on an earlier claim that direction and extent of movements are planned independently (Krakauer, Pine, Ghilardi, and Ghez, J Neurosci, 2000). Figure 1: Reach endpoint adaptation to 15º directional target jump. Reach errors are shown as angular deviation over trials for 6 subjects. Figure 1 Keywords: computational neuroscience Conference: Bernstein Conference on Computational Neuroscience, Berlin, Germany, 27 Sep - 1 Oct, 2010. Presentation Type: Presentation Topic: Bernstein Conference on Computational Neuroscience Citation: Westendorff S, Taghizadeh B and Gail A (2010). Generalization patterns during reach adaptation to target jump. Front. Comput. Neurosci. Conference Abstract: Bernstein Conference on Computational Neuroscience. doi: 10.3389/conf.fncom.2010.51.00018 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 22 Sep 2010; Published Online: 23 Sep 2010. * Correspondence: Dr. Stephanie Westendorff, German Primate Center, Sensorimotor Group, BCCN Göttingen, Göttingen, Germany, swesten@gwdg.de Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Stephanie Westendorff Bahareh Taghizadeh Alexander Gail Google Stephanie Westendorff Bahareh Taghizadeh Alexander Gail Google Scholar Stephanie Westendorff Bahareh Taghizadeh Alexander Gail PubMed Stephanie Westendorff Bahareh Taghizadeh Alexander Gail Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.