Visual information about the environment, especially fixation of key objects such as obstacles, is critical for safe locomotion. However, in unpredictable situations where an obstacle suddenly appears it is not known whether central vision of the obstacle and/or landing area is required or if peripheral vision is sufficient. We examined whether there is a re-direction of visual fixation from an object fixated ahead to a suddenly appearing obstacle during treadmill walking. Furthermore, we investigated the temporal relationship between the onset of muscle activity to avoid the obstacle and saccadic eye and head movements to shift fixation. Eight females (mean SD; age = 24.8 2.3 years) participated in this experiment. There were two visual conditions: a central vision condition where participants fixated on two obstacles attached to a bridge on the treadmill and a peripheral vision condition where participants fixated an object two steps ahead. There were two obstacle release conditions: only an obstacle in front of the left foot was released or an obstacle in front of either foot could be released. Only trials when the obstacle was released in front of the left foot were analyzed such that the difference in the two obstacle conditions was whether there was a choice of which foot to step over the obstacle. Obstacles were released randomly in one of three phases during the step cycle corresponding to available response times between 219 and 462 ms. We monitored eye and head movements along with muscle activity and spatial foot parameters. Performance on the task was not different between vision conditions. The results indicated that saccades are rarely made (less than 18% of trials) and, when present, are initiated ∼ 350 ms after muscle activity for limb elevation, often accompanied by a downward head movement, and always directed to the landing area. Therefore, peripheral vision of a suddenly appearing obstacle in the travel path is sufficient for successful obstacle avoidance during locomotion: visual fixation is generally not re-directed to either the obstacle or landing area.


    Access

    Download


    Export, share and cite



    Title :

    Keep looking ahead? Re-direction of visual fixation does not always occur during an unpredictable obstacle avoidance task


    Contributors:

    Publication date :

    2007-01-01


    Remarks:

    Marigold , D , Weerdesteyn , V , Patla , A & Duysens , J 2007 , ' Keep looking ahead? Re-direction of visual fixation does not always occur during an unpredictable obstacle avoidance task ' , Experimental Brain Research , vol. 176 , no. 1 , pp. 32-42 .


    Type of media :

    Article (Journal)


    Type of material :

    Electronic Resource


    Language :

    English


    Classification :

    DDC:    629



    ISeVis: Indoor Scene Visual Obstacle Avoidance

    SWIFT Gesellschaft für Messwerterfassungs-Systeme mbH | Mobilithek

    Free access

    Obstacle avoidance during target tracking

    ZHAO CONG / SHEN SHAOJIE / QIAN JIE et al. | European Patent Office | 2025

    Free access

    OBSTACLE AVOIDANCE DURING TARGET TRACKING

    ZHAO CONG / SHEN SHAOJIE / QIAN JIE et al. | European Patent Office | 2025

    Free access

    Obstacle avoidance during target tracking

    ZHAO CONG / SHEN SHAOJIE / QIAN JIE et al. | European Patent Office | 2023

    Free access

    Obstacle avoidance during target tracking

    ZHAO CONG / SHEN SHAOJIE / QIAN JIE et al. | European Patent Office | 2021

    Free access