Effects of roll visual motion on online control of arm movement: reaching within a dynamic virtual environment |
| |
Authors: | Dvorkin Assaf Y Kenyon Robert V Keshner Emily A |
| |
Institution: | (1) Sensory Motor Performance Program, Rehabilitation Institute of Chicago, 345 East Superior Street, Chicago, IL 60611, USA;(2) Department of Computer Science, University of Illinois at Chicago, Chicago, IL, USA;(3) Department of Physical Medicine and Rehabilitation, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA;(4) Departments of Physical Therapy and Electrical Engineering and Computer Science, Temple University, Philadelphia, PA, USA |
| |
Abstract: | Reaching toward a visual target involves the transformation of visual information into appropriate motor commands. Complex
movements often occur either while we are moving or when objects in the world move around us, thus changing the spatial relationship
between our hand and the space in which we plan to reach. This study investigated whether rotation of a wide field-of-view
immersive scene produced by a virtual environment affected online visuomotor control during a double-step reaching task. A
total of 20 seated healthy subjects reached for a visual target that remained stationary in space or unpredictably shifted
to a second position (either to the right or left of its initial position) with different inter-stimulus intervals. Eleven
subjects completed two experiments which were similar except for the duration of the target’s appearance. The final target
was either visible throughout the entire trial or only for a period of 200 ms. Movements were performed under two visual field
conditions: the virtual scene was matched to the subject’s head motion or rolled about the line of sight counterclockwise
at 130°/s. Nine additional subjects completed a third experiment in which the direction of the rolling scene was manipulated
(i.e., clockwise and counterclockwise). Our results showed that while all subjects were able to modify their hand trajectory
in response to the target shift with both visual scenes, some of the double-step movements contained a pause prior to modifying
trajectory direction. Furthermore, our findings indicated that both the timing and kinematic adjustments of the reach were
affected by roll motion of the scene. Both planning and execution of the reach were affected by roll motion. Changes in proportion
of trajectory types, and significantly longer pauses that occurred during the reach in the presence of roll motion suggest
that background roll motion mainly interfered with the ability to update the visuomotor response to the target displacement.
Furthermore, the reaching movement was affected differentially by the direction of roll motion. Subjects demonstrated a stronger
effect of visual motion on movements taking place in the direction of visual roll (e.g., leftward movements during counterclockwise
roll). Further investigation of the hand path revealed significant changes during roll motion for both the area and shape
of the 95% tolerance ellipses that were constructed from the hand position following the main movement termination. These
changes corresponded with a hand drift that would suggest that subjects were relying more on proprioceptive information to
estimate the arm position in space during roll motion of the visual field. We conclude that both the spatial and temporal
kinematics of the reach movement were affected by the motion of the visual field, suggesting interference with the ability
to simultaneously process two consecutive stimuli. |
| |
Keywords: | Visuomotor control Virtual reality Double-step paradigm Roll motion |
本文献已被 PubMed SpringerLink 等数据库收录! |
|