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| Research article summary (published 13 Apr 2009): |
Dynamics of smooth pursuit maintenance.
Full Abstract
Smooth pursuit eye movements allow the approximate stabilization of a moving visual target on the retina. To study the dynamics of smooth pursuit, we measured eye velocity during the visual tracking of a Gabor target moving at a constant velocity plus a noisy perturbation term. The optimal linear filter linking fluctuations in target velocity to evoked fluctuations in eye velocity was computed. These filters predicted eye velocity to novel stimuli in the 0- to 15-Hz band with good accuracy, showing that pursuit maintenance is approximately linear under these conditions. The shape of the filters were indicative of fast dynamics, with pure delays of merely approximately 67 ms, times-to-peak of approximately 115 ms, and effective integration times of approximately 45 ms. The gain of the system, reflected in the amplitude of the filters, was inversely proportional to the size of the velocity fluctuations and independent of the target mean speed. A modest slow-down of the dynamics was observed as the contrast of the target decreased. Finally, the temporal filters recovered during fixation and pursuit were similar in shape, supporting the notion that they might share a common underlying circuitry. These findings show that the visual tracking of moving objects by the human eye includes a reflexive-like pathway with high contrast sensitivity and fast dynamics.
Author information
Author/s: Tavassoli, Abtine (A); Ringach, Dario L (DL);
Affiliation: Department of Neurobiology, Jules Stein Eye Institute, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA.
Grants: EY-12816 (Agency:NEI NIH HHS) ; EY-18322 (Agency:NEI NIH HHS)
Journal and publication information
Publication Type: Journal Article; Research Support, N.I.H., Extramural
Journal: Journal of neurophysiology (J Neurophysiol), published in United States. (Language: eng)
Reference: 2009-Jul; vol 102 (issue 1) : pp 110-8
Dates: Created 2009/06/30; Completed 2009/09/10;
PMID: 19369357, status: MEDLINE (last retrieved date: 9/10/2009)
Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.
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