The influence of advance information about target location and visual feedback on movement planning and execution.

Abstract

This study was designed to determine if movement planning strategies incorporating the use of visual feedback during manual aiming are specific to individual movements. Advance information about target location and visual context was manipulated using precues. Participants exhibited a shorter reaction time and a longer movement time when they were certain of the target location and that vision would be available. The longer movement time was associated with greater time after peak velocity. Under conditions of uncertainty, participants prepared for the worst-case scenario. That is, they spent more time organizing their movements and produced trajectories that would be expected from greater open-loop control. Our results are consistent with hierarchical movement planning in which knowledge of the movement goal is an essential ingredient of visual feedback utilization.

Common vs. independent limb control in sequential vertical aiming: The cost of potential errors during extensions and reversals

“…This resulted in similar endpoint accuracy, although there was lower variability at the near target in the upward compared to downward aiming direction. Thus, upward aims featured a greater impulse than downward aims, which was likely a result of increased contributions from feedforward planning procedures (efference) (Elliott et al, 2010;Hansen, Glazebrook, Anson, Weeks, & Elliott, 2006;Khan, Franks, & Goodman, 1998). This pattern of results is consistent with our original suggestion of individuals accommodating the cost of potential target overshoots by providing a low magnitude initial impulse when aiming downwards, as an overshoot in this instance would require more energy-consuming corrections against gravitational forces (Lyons et al, 2006).…”

Visual regulation of manual aiming: A comparison of methods

“…This vision/no-vision difference was more pronounced in Block 2 than in Block 1 (Block 1: vision 282 msec, no vision 314 msec; Block 2: vision 260 msec, no vision 317 msec). This finding is similar to previous results from our lab (e.g., Elliott & Allard, 1985;Hansen, Glazebrook, Anson, Weeks, & Elliott, 2006;Khan et al, 2002) and has been interpreted to mean that participants take the time to prepare a more precise initial submovement when they know that there will not be an opportunity for online visual regulation during movement execution.…”

“…In recent years, it has become apparent that visual regulation can begin quite early in an aiming movement and that corrective processes are not always discrete in nature (e.g., Elliott et al, 1991;Grierson & Elliott, 2009;Hansen et al, 2006;Khan et al, 2002;Khan et al, 1998;Proteau & Masson, 1997), especially when a perturbation of the target changes the physical requirements of the task (e.g., Hansen & Elliott, 2009;Heath et al, 1998). This type of finding has motivated researchers to consider methodological approaches that do not depend on the identification of discrete discontinuities in aiming profiles.…”

To know or not to know: influence of explicit advance knowledge of occlusion on interceptive actions

“…Subsequently, it was confirmed that participants also adopt different movement strategies depending on their advance knowledge. For instance, movement kinematics are consistent with an optimized use of visual feedback when an occlusion is expected, compared to a default strategy when occlusion and no occlusion of vision are equally likely (Jakobson and Goodale 1991;Khan et al 2002;Hansen et al 2006). Neural evidence for the influence of advance knowledge has been shown in motor learning (Willingham et al 2002).…”

“…However, no change in the timing of the grasp was predicted as this has previously been shown to be robust against visual occlusion (Mazyn et al 2007b). In the absence of explicit advance knowledge, it was hypothesized that participants would respond initially with a default control strategy irrespective of the presence and duration of visual occlusion (Jakobson and Goodale 1991;Khan et al 2002;Hansen et al 2006;Mazyn et al 2007b). …”