Abstract

Early aiming adjustments following an online perturbation are made possible by impulse control. This process may unfold even earlier when perturbations impose a greater risk of a costly overshoot error. Participants executed upward and downward aims to mediate the cost of potential errors—downward overshoots require more energy to correct against gravity. On 33% of the trials, texture elements on the aiming surface were shifted following onset to appear congruent or incongruent with the aiming direction, and consequently generate a misperception of the limb moving slower or faster, respectively. Thus, the risk of potential errors could be influenced by the online perturbation (e.g., increased perceived likelihood of overshooting following the incongruent background). Findings indicated greater undershooting for down compared to up, which reflects the principle of movement optimisation. There was also more undershooting for an incongruent compared to congruent background, which is consistent with early online adjustments counter-acting the misperceived limb velocity. However, there were no interactions throughout the movement trajectory. We suggest that while the initial pre-programme considers the cost of potential errors (target direction), early impulse control fails to discriminate the likelihood of these errors occurring following an online perturbation (moving background).

摘要

通过脉冲控制可以实现在线干扰后的早期瞄准调整。当扰动带来更大的过冲错误风险时，此过程可能会更早展开。向上和向下执行的参与者旨在调解潜在错误的成本-向下超调需要更多的精力来克服重力。在33％的试验中，瞄准表面上的纹理元素在发作后发生移动，以与瞄准方向一致或不一致，因此分别产生对肢体移动得较慢或更快的误解。因此，潜在的错误风险可能会受到在线干扰的影响（例如，在不一致的背景下，出现过冲的可能性增加了）。调查结果表明，向下调整的下冲比向上调整的下冲更大，这反映了运动优化的原理。与一致背景相比，不一致的下冲也更多，这与早期的在线调整相抵消，以抵消误解的肢体速度。但是，在整个运动轨迹中没有交互作用。我们建议，尽管最初的预编程考虑了潜在错误（目标方向）的成本，但早期的冲动控制无法区分这些错误在在线干扰（运动背景）之后发生的可能性。