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Saccade-stepping interactions revise the motor plan for obstacle avoidance.

Richard P Di Fabio·John F Greany·Cris Zampieri
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Abstract

The authors used a stimulus-response compatibility paradigm to assess the effect of changing the estimated time to obstacle contact. A limb-selection cue was presented in different phases of gait to young (n = 5) and to older (n = 4) adults while they were moving toward a foam obstacle in the walking path. A downward saccade was initiated after the cue; the saccade typically occurred during the stance phase of the target limb (the foot cued to lead the step over the obstacle). The mean saccade-step latency after the cue was on the order of -500 ms in both young and elderly participants. On reaching the obstacle, both groups generated an upward saccade approximately -300 ms before target footlift in both groups. Saccades following the limb-selection cue appeared to direct the gaze toward footfall targets just beyond the obstacle, whereas saccades generated just before obstacle footlift moved the gaze to the forward-looking direction. The elderly had significantly longer saccade-trailing-footlift latencies and prolonged gaze-fixation times than did the younger adults. Transient disruptions in optical flow appeared to be necessary for successful obstacle-avoidance behavior when there was an unexpected change in the estimated time to obstacle contact.

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AdultAgedAged, 80 and overAgingAvoidance LearningBiomechanical PhenomenaFemaleFunctional LateralityGaitHumansKinesthesisMaleOrientationProblem SolvingReaction TimeSaccadesWalkingJournal ArticleResearch Support, Non-U.S. Gov'tResearch Support, U.S. Gov't, P.H.S.

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Richard P Di Fabio, John F Greany, Cris Zampieri. 2003. Saccade-stepping interactions revise the motor plan for obstacle avoidance.. https://doi.org/10.1080/00222890309603158

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