The intertwined roles of vision and sensorimotor adaptation on reach-to-grasp movements

当我们采取日常行动，比如拿起一杯咖啡时，我们的大脑需要弄清楚杯子的位置、形状和重量(这取决于杯子的装满程度)。我们倾向于认为，我们对杯子的感知体验决定了我们与它的互动。然而，过去20年的几项研究一再表明，感知任务，如判断物体的大小或重量，是由大脑中不同的部分处理的，而不是由行动任务处理的，比如伸手抬起物体。这个项目采取了另一种观点，大脑处理视觉场景，但这个过程可能会出现错误(比如高估了杯子的大小或重量)。当动作展开时，这些错误被立即检测到，并且随后朝向对象的移动被快速校正。这项研究计划将探索这些复杂更正的性质。它还将检查某些情况，在这些情况下，我们的感知是错误的，而我们的行动是准确的。这些知识可以帮助人们快速学习新的视觉运动技能，如在虚拟现实环境中互动和远程操作。事实上，对视觉引导动作的更全面的理解可以为这些新兴技术的发展提供信息。最后，这项提议的发现可能有助于改善神经障碍患者的生活，这些障碍往往会导致严重的运动能力丧失，严重影响日常生活活动。这项研究项目使用最先进的虚拟现实环境来测试1)人类可以在多大程度上调整他们的运动动作，以弥补视觉感知的不准确，以及2)当无法通过运动调整实现平稳运动协调时，视觉感知是否会发生变化。将测试三种机械假说，在这些假说中，感觉预测误差--当感觉反馈与一个人的预期不符时产生的信号--在重复的视觉运动交互中提高动作的准确性。每个假说的核心都是这样一种观点，即当感知偏差导致不准确的动作时，感觉预测误差将在整个感觉运动系统中驱动适应性变化。将测试三种不相互排斥的适应性变化机制：(1)运动输出与物理世界的快速重新匹配，(2)视觉感知校准的变化，和/或(3)视觉信息特定方面对行动的贡献的选择性变化。为了验证这些假设，将进行一套完整的行为实验，同时开发计算模型，以机械地解释感知和行动的紧密相互交织的角色。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

When we perform mundane daily actions like picking up a cup of coffee, our brain needs to figure out the location of the cup, its shape and weight (which changes depending on how full it is). We tend to think that our perceptual experience of the cup is what determines our interaction with it. However, several studies over the past two decades have repeatedly shown that a perceptual task, like judging the size of an object or its weight, is processed by a different part of the brain than an action task, like reaching to lift the object. This project takes an alternate view, in which the brain processes the visual scene, but this process may be subject to errors (like overestimating the size of a cup or its weight). These errors are immediately detected while an action is unfolding and the subsequent movements toward the object are quickly corrected. This research plan will explore the nature of these complex corrections. It will also examine certain circumstances in which our perception is faulty while our actions are accurate. This knowledge could help people rapidly learn new visuomotor skills, such as interacting in virtual-reality environments and teleoperation. Indeed, a more comprehensive understanding of visually guided action could inform the development of these emerging technologies. Finally, discoveries from this proposal could help improve the lives of individuals with neurological disorders, which often lead to a profound loss of motor ability that significantly impairs activities of daily living. This research project uses state-of-the-art virtual reality environments to test 1) to what extent humans can adjust their motor actions "on the fly" to compensate for inaccuracies in visual perception and 2) whether visual perception changes when smooth movement coordination cannot be achieved through motor adjustments. Three mechanistic hypotheses will be tested in which sensory-prediction errors - signals produced when sensory feedback does not match one's expectations - enhance the accuracy of action during repeated visuomotor interactions. At the core of each hypothesis is the idea that when biases in perception lead to inaccurate movements, sensory-prediction errors will drive adaptive changes across the sensorimotor system. Three non-mutually exclusive mechanisms of adaptive change will be tested: (1) Rapid re-alignment of the motor output with the physical world, (2) Changes in calibration of visual perception, and/or (3) Selective changes in the contribution of specific aspects of visual information to action. To test these hypotheses, an integrated set of behavioral experiments will be conducted, in tandem with the development of computational models to mechanistically explain the closely intertwined roles of perception and action.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.