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Conference Paper: The influence of optic flow on control of walking gradually increases over the course of a movement

TitleThe influence of optic flow on control of walking gradually increases over the course of a movement
Authors
KeywordsMedical sciences
Ophthalmology and optometry
Issue Date2012
PublisherAssociation for Research in Vision and Ophthalmology. The Journal's web site is located at http://wwwjournalofvisionorg/
Citation
The 12th Annual Meeting of the Vision Sciences Society (VSS 2012), Naples, FL., 11-16 May 2012. In Journal of Vision, 2012, v. 12 n. 9, article 608 How to Cite?
AbstractDifferent heading-based strategies could be used to guide walking to a target. Observers could potentially align the visual direction of the target with their physical direction of movement, or their visual heading from optic flow, or some integrated estimate of heading. I investigated the relative influence of visual and physical heading on control of walking, and how this varies over the course of a movement. Previous studies have distinguished control strategies using conditions in which the visual heading specified by optic flow differs from an observer’s physical direction of motion. I tested similar conditions but used a novel analysis to estimate the controller’s goal state at different moments in time. Observers walked to a target pole in a virtual environment presented with a head-mounted display. On perturbed trials, visual heading differed from physical heading by ±10°. The target appeared after observers walked 1m in a pre-cued direction, and was randomly positioned in a range around the initial direction. I analyzed how path corrections across a brief time window depended on the current heading error relative to the target. Across a given time delay, change in heading was an approximately linear function of heading error. By fitting this function, one can estimate the heading error that would produce no steering adjustment across a time window. This goal state was estimated for 250 ms windows starting at target onset. Initial steering adjustments on perturbed trials were consistent with a goal state of aligning the physical heading direction with the target. Over the course of 2 s of walking, the estimated goal state gradually shifted to be approximately midway between the physical and visual heading. These results are consistent with control based on an integrated estimate of heading, which is initially determined by non-visual information but gradually incorporates heading information from optic flow.
DescriptionThis journal issue is meeting abstracts presented at VSS 2012
Open Access Journal
Persistent Identifierhttp://hdl.handle.net/10722/153168
ISSN
2015 Impact Factor: 2.341
2015 SCImago Journal Rankings: 1.042

 

DC FieldValueLanguage
dc.contributor.authorSaunders, JAen_US
dc.date.accessioned2012-07-16T09:58:51Z-
dc.date.available2012-07-16T09:58:51Z-
dc.date.issued2012en_US
dc.identifier.citationThe 12th Annual Meeting of the Vision Sciences Society (VSS 2012), Naples, FL., 11-16 May 2012. In Journal of Vision, 2012, v. 12 n. 9, article 608en_US
dc.identifier.issn1534-7362-
dc.identifier.urihttp://hdl.handle.net/10722/153168-
dc.descriptionThis journal issue is meeting abstracts presented at VSS 2012-
dc.descriptionOpen Access Journal-
dc.description.abstractDifferent heading-based strategies could be used to guide walking to a target. Observers could potentially align the visual direction of the target with their physical direction of movement, or their visual heading from optic flow, or some integrated estimate of heading. I investigated the relative influence of visual and physical heading on control of walking, and how this varies over the course of a movement. Previous studies have distinguished control strategies using conditions in which the visual heading specified by optic flow differs from an observer’s physical direction of motion. I tested similar conditions but used a novel analysis to estimate the controller’s goal state at different moments in time. Observers walked to a target pole in a virtual environment presented with a head-mounted display. On perturbed trials, visual heading differed from physical heading by ±10°. The target appeared after observers walked 1m in a pre-cued direction, and was randomly positioned in a range around the initial direction. I analyzed how path corrections across a brief time window depended on the current heading error relative to the target. Across a given time delay, change in heading was an approximately linear function of heading error. By fitting this function, one can estimate the heading error that would produce no steering adjustment across a time window. This goal state was estimated for 250 ms windows starting at target onset. Initial steering adjustments on perturbed trials were consistent with a goal state of aligning the physical heading direction with the target. Over the course of 2 s of walking, the estimated goal state gradually shifted to be approximately midway between the physical and visual heading. These results are consistent with control based on an integrated estimate of heading, which is initially determined by non-visual information but gradually incorporates heading information from optic flow.-
dc.languageengen_US
dc.publisherAssociation for Research in Vision and Ophthalmology. The Journal's web site is located at http://wwwjournalofvisionorg/-
dc.relation.ispartofJournal of Visionen_US
dc.subjectMedical sciences-
dc.subjectOphthalmology and optometry-
dc.titleThe influence of optic flow on control of walking gradually increases over the course of a movementen_US
dc.typeConference_Paperen_US
dc.identifier.emailSaunders, JA: jsaun@hkucc.hku.hken_US
dc.identifier.authoritySaunders, JA=rp00638en_US
dc.description.naturelink_to_OA_fulltext-
dc.identifier.doi10.1167/12.9.608-
dc.identifier.hkuros201586en_US
dc.identifier.volume12-
dc.identifier.issue9-
dc.publisher.placeUnited States-

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