Abstract
Recently, we have observed that providing vision between 0.8 and 1.4 m/s (i.e., prior to peak velocity) resulted in movement endpoint distributions as precise as with full vision. This limb velocity range coincides with seeing the limb at approximately 18-20° of visual eccentricity (i.e., peak rod density on the retina). As such, it is possible that the common observation that vision can be used rather early in the trajectory is related to the visual eccentricity of the limb when vision is provided. We thus aimed to determine if the use of vision to control a goal-directed movement varies as a function of retinal limb position. Sixteen (16) participants completed a discrete reaching movement following a 2 viewing distances (30, 50 cm) X 4 vision conditions (early-, late-, full- and no-vision) experimental design. The early and late vision conditions yielded eccentricity ranges of 11° to 15°, 17° to 22°, and 25° to 33°, as well as between 34 and 58 ms of vision. Movement endpoint analyses revealed that trials in the early, late and no-vision conditions were not significantly different from each other but were significantly less accurate and precise than full vision trials (Fs > 17; ps < .01). While these results suggest that the use of vision during limb movements is not directly tied to the neuroanatomy of the eye, we were surprised not to reproduce significant effects of brief visual samples on the control of a voluntary movement. This research was supported by NSERC.Acknowledgments: This research was supported by NSERC.