Asymmetric generalization of target jump adaptation suggests tuning changes at the level of motor goals -- a neuronal network simulation

Abstract

Event Abstract Back to Event Asymmetric generalization of target jump adaptation suggests tuning changes at the level of motor goals -- a neuronal network simulation Stephanie Westendorff1, 2, Shenbing Kuang1, Opher Donchin3 and Alexander Gail1, 2* 1 German Primate Center, Germany 2 Bernstein Center for Computational Neuroscience, Germany 3 Ben-Gurion University of the Negev, Israel We previously presented a behavioral target jump paradigm (Westendorff et al., 2010), in which reach movements reliably adapted to target error alone, without prediction error caused by perturbed feedback about the hand position. The target jump task induced adaptation with an asymmetric generalization, i.e. reach corrections for the adapted target were transferred more strongly towards unperturbed probe targets which lay in the direction of the target jump, compared to probe targets in the opposite direction. We here present a three-layer recurrent neuronal network with which we can simulate the reach adaptation behavior of the target jump paradigm. The presented model was previously used for simulating context-specific sensorimotor transformations (Brozovic, 2007) and needed only minor modifications for simulating the target jump task. After learning a 1-to-1 standard mapping from spatially local sensory input to a congruent motor output across the whole workspace, the model was re-trained at a single spatial position to perform a 15º rotation of the motor output relative to the local sensory input. In this adapted state the generalization of adaptation effects to unperturbed probe target locations was measured equivalently to human psychophysics. We analyzed the changes in the neuronal tuning properties at the different levels of the model in response to the induced target jump adaptation. The model reproduces the asymmetry in generalization observed in the experimental data. The strength of the asymmetry is dependent on the tuning width of neurons in the output layer, but can be robustly found over a wide range of parameters. The asymmetry of generalization is contingent upon changes of tuning properties in the hidden layer. If tuning changes in the hidden layer were prevented, than the model still adapted to the local target jump but showed symmetric generalization, which does not match the psychophysical results. This implies that adaptation in the learning model is achieved by changes in the mapping from the input to the hidden layer, rather than changes in the mapping from the hidden to the output layer. Our results suggest that adaptation in our target jump task likely affects motor goal representations at early visuospatial stages of reach planning, rather than changes at the motor execution level. The simulations predict specific changes of tuning properties in areas like the posterior parietal cortex during target jump adaptation. References Brozovic et al. 2007 JNeurosci:27:10588. Westendorff et al 2011 Soc Neurosci Abstr 292.8 Keywords: adaptation, generalization, motor goal, Neurons, networks and dynamical systems, reach, target jump Conference: BC11 : Computational Neuroscience & Neurotechnology Bernstein Conference & Neurex Annual Meeting 2011, Freiburg, Germany, 4 Oct - 6 Oct, 2011. Presentation Type: Poster Topic: neurons, networks and dynamical systems (please use "neurons, networks and dynamical systems" as keywords) Citation: Westendorff S, Kuang S, Donchin O and Gail A (2011). Asymmetric generalization of target jump adaptation suggests tuning changes at the level of motor goals -- a neuronal network simulation. Front. Comput. Neurosci. Conference Abstract: BC11 : Computational Neuroscience & Neurotechnology Bernstein Conference & Neurex Annual Meeting 2011. doi: 10.3389/conf.fncom.2011.53.00050 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: 23 Aug 2011; Published Online: 04 Oct 2011. * Correspondence: Dr. Alexander Gail, German Primate Center, Göttingen, Germany, agail@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 Shenbing Kuang Opher Donchin Alexander Gail Google Stephanie Westendorff Shenbing Kuang Opher Donchin Alexander Gail Google Scholar Stephanie Westendorff Shenbing Kuang Opher Donchin Alexander Gail PubMed Stephanie Westendorff Shenbing Kuang Opher Donchin 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.