On the feed-forward control of eye-head coordination

Abstract

Event Abstract Back to Event On the feed-forward control of eye-head coordination Murat Sağlam1, 2*, Nadine Lehnen1, 3 and Stefan Glasauer1, 2, 4 1 Integrated Center for Research and Treatment of Vertigo, Germany 2 Institute for Clinical Neurosciences, Germany 3 Department of Neurology, Ludwig-Maximilians University, Germany 4 Bernstein Center for Computational Neuroscience, Germany Large human gaze shifts consist of two parts: one where eye and head move together towards the target and one where gaze has reached the target and is stabilized while the head continues to move. During this stabilization phase, the eyes counter-rotate to account for the ongoing head movement. This counter-rotation could be actively performed as a part of a pre-programmed plan or mediated via a sensory, e.g., vestibular, feedback-loop. Recently, we proposed an optimal control model based on a physiologically consistent criterion, which ensures that the impact of two types of noise, namely signal-dependent and constant (signal-independent) noise, on the variability of the final gaze position is minimized (Sağlam et al., 2011). Our model, which accounts for the main features of eye and head kinematics, shows that the compensatory counter-rotation of the eyes is cost efficient in terms of end-point variability. This suggests that a feed-forward strategy to drive the counter-rotation would be beneficial. To examine whether humans use such a strategy to stabilize gaze, we investigated healthy subjects and labyrinthine-defective patients while they performed large horizontal gaze shifts to a flashed target in darkness. After a block of natural gaze shifts, their head moment inertia was increased by means of a helmet with eccentrically attached masses. Under natural conditions, similar to normal subjects, labyrinthine-defective patients stabilized gaze by eye counter-rotation. In both groups, increasing the head moment of inertia led to head oscillations that originated from the mismatch between the altered head and the control command, which was appropriate for the natural head. The eye movements of healthy subjects compensated for these oscillations. Labyrinthine-defective patients however could not compensate for the head oscillations and thus showed gaze oscillations. This suggests that humans make use of feed-forward control to perform accurate gaze shifts with a counter-rotation strategy and, in addition, are able to counteract undesired head movements with vestibular feedback. Although the head oscillations are compensated for by the vestibular feedback, healthy subjects minimize head oscillations within the first 10 trials by updating their motor command. This suggests that the feed-forward plan is pre-programmed without taking the vestibular feedback mechanism into account, probably because the vestibular system cannot perfectly eliminate the impact of head oscillations. Acknowledgements supported by BMBF (grant IFB 01EO0901 ) References Sağlam M, Lehnen N, Glasauer S, Optimal Control of Natural Eye-Head Movements Minimizes the Impact of Noise,The Journal of Neuroscience, 31:16185-93, 2011 Keywords: eye-head coordination, gaze shifts, optimal control Conference: Bernstein Conference 2012, Munich, Germany, 12 Sep - 14 Sep, 2012. Presentation Type: Poster Topic: Motor control, movement, navigation Citation: Sağlam M, Lehnen N and Glasauer S (2012). On the feed-forward control of eye-head coordination. Front. Comput. Neurosci. Conference Abstract: Bernstein Conference 2012. doi: 10.3389/conf.fncom.2012.55.00144 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: 11 May 2012; Published Online: 12 Sep 2012. * Correspondence: Dr. Murat Sağlam, Integrated Center for Research and Treatment of Vertigo, Munich, Germany, murat.saglam@lrz.uni-muenchen.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 Murat Sağlam Nadine Lehnen Stefan Glasauer Google Murat Sağlam Nadine Lehnen Stefan Glasauer Google Scholar Murat Sağlam Nadine Lehnen Stefan Glasauer PubMed Murat Sağlam Nadine Lehnen Stefan Glasauer 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.