Abstract
It has been suggested that vision is particularly important to plan the amplitude of voluntary upper-limb reaches while proprioception is important for the online control (e.g., Bagesteiro et al., 2006). One possible concern with such research is the use of a visual-proprioceptive mismatch to assess proprioceptive feedback contributions. In order to assess the relative use of visual and proprioceptive feedback during the control of action, vision occlusion and tendon vibration were employed. Participants (n=15) performed a simple voluntary reaching task (30 cm). Liquid-crystal goggles were used to manipulate vision between movement onset and offset. The biceps and triceps muscles’ distal tendons were simultaneously vibrated between trials only, which yields decreased proprioceptive sensation, even when the vibration is stopped. Right index finger trajectories were recorded to obtain movement kinematics and endpoint performance. Movement times were longer with online vision while longer times after peak velocity were observed with online vision and without tendon vibration. Both manipulations significantly influenced endpoint bias, in both the amplitude and direction axes of the movement. Vision withdrawal yielded larger endpoint distributions in both axes while tendon vibration significantly influenced endpoint variability only in the amplitude axis. A 2 vision (full, none) by 2 vibration (on, off) by 4 movement time proportion (25%, 50%, 75%, 100%) ANOVA of the standard deviation of the finger position in the amplitude axis only revealed a main effect of vibration. For the same ANOVA employed with the direction axis, vision did yield a significant main effect while a proportion by vibration interaction revealed more trajectory variability with vibration at 75% of movement time. Overall, the results indicate that vision is relatively more important than proprioception to control trajectories in the amplitude movement axis while both modalities are important to control trajectories the direction of the movement.Acknowledgments: Natural Sciences and Engineering Research Council of Canada (NSERC); Canada Foundation for Innovation (CFI); Ontario Research Fund (ORF); Perceptual Motor Behaviour Laboratory