Decision making in action planning and control

现实世界的动作任务涉及一系列决策过程，这些过程基于展开任务期间提取的信息来确定下一步要做什么运动，以及何时做运动。然而，关于运动控制和决策的研究在很大程度上是孤立发展的，直到最近，研究人员才开始研究它们之间的相互作用。这项拟议的研究的主要目的是通过研究人类目标定向到达任务的决策过程，更好地了解大脑如何控制行动。拟议的研究由四个相互关联的项目组成。 虽然大多数关于触觉的研究都集中在对单个目标的运动上，但在现实世界中，我们经常面临多个潜在的行动目标。项目1的目的是研究在这些目标不确定的情况下，大脑是如何准备伸展运动的。最近的研究表明，在REACH准备过程中，大脑编码多个潜在目标，在指定目标之前启动的REACH初始方向受到潜在目标分布的偏差。这些结果与这样一种观点是一致的，即人们准备了通往潜在目标的多个覆盖范围计划，但也与这样一个概念一致，即在目标不确定的情况下，人们在战略方向上计划单一的覆盖范围。我们将在这些选择之间进行批判性的测试。 许多自然任务涉及在每一步从备选方案中选择一系列目标，而最优觅食理论为研究与不同目标或目标序列相关的回报和成本如何影响目标选择行为提供了一个自然框架。尽管有一些研究考察了价值和成本如何影响单一目标的选择，但据我们所知，还没有研究过顺序目标选择。项目2将使用我们最近开发的移动觅食任务来调查与顺序目标选择相关的决策。 根据对学习成本和回报的评估，人们经常面临投资学习一项新技能是否值得的决定。然而，就我们所知，这种与技能学习相关的决策还没有被定量研究。项目3将研究学习和奖赏优化之间的相互作用，使用可及性任务，参与者可以选择是否参与运动学习，这最终将使他们获得更高的价值奖励。一个关键目标是评估参与者利用有关自身能力的知识学习新技能的能力，以便就是否投资于此类学习做出正确决定。 对动作观察的研究表明，观察者提取有关演员目标的信息。然而，还没有研究考察在观看涉及决策的动作任务时，观察者是否会提取潜在的有价值的信息来指导参与者的选择。我们之前已经证明，一旦观察者能够预测到目标，他们就会将他们的目光指向演员移动的目标。在项目4中，我们将记录观察者的眼动，以测试他们在选择到达目标时是否学会预测参与者的选择行为，暗示观察者可能提取参与者与目标相关联的价值和成本。

Real-world action tasks involve a sequence of decision-making processes that determine, based on information extracted during the unfolding task, which movement to make next and when to make it. However, research on movement control and decision-making has largely evolved in isolation, and it is only recently that researchers have begun to examine the interplay between them. The broad aim of the proposed research is to better understand how the brain controls action by investigating decision-making processes in the context of human target-directed reaching tasks. The proposed research consists of four interrelated projects. Whereas most studies of reaching have focused on movements made to single targets, in the real world we are often confronted with multiple potential targets of action. The aim of PROJECT 1 is to investigate how the brain prepared a reaching movement under these conditions of target uncertainty. Recent work has shown that during reach preparation, the brain encodes multiple potential targets and that the initial direction of reaches initiated before the target is specified, is biased by the distribution of potential targets. These results are consistent with the idea that multiple reach plans to potential target are prepared but are also consistent with the notion that, in cases of target uncertainty, people plan a single reach in a strategic direction. We will critically test between these alternatives. Many natural tasks involve choosing a sequence of targets from alternatives at each step and optimal foraging theory provides a natural framework for examining how rewards and costs associated with different targets, or target sequences, influence target choice behaviour. Although a handful of studies have examined how values and cost influence the selection of single targets, to our knowledge no study has investigated sequential target selection. PROJECT 2 will investigate decision-making related to sequential target selection using a movement foraging task that we have recently developed. People are frequently confronted with decisions about whether it is worthwhile investing in learning a new skill, based on an evaluation of the costs and rewards associated with learning. However, to our knowledge such decision-making related to skill learning has not been quantitatively studied. PROJECT 3 will investigate the interaction between learning and reward optimization using reaching tasks in which participants can choose whether to engage in motor learning, which will ultimately enable them to obtain higher value rewards. A key aim is to assess participants’ ability to use knowledge about their own ability to learn new skills to make good decisions about whether to invest in such learning. Studies of action-observation have shown that observers extract information about the actor’s goals. However, no research has examined whether, when watching action tasks involving decision-making, observers extract potentially valuable information that guides the actor’s choices. We have previously shown that observers direct their gaze to the target of an actor’s movement as soon as they can predict the target. In PROJECT 4, we will record observer’s eye movements to test whether they learn to predict an actor’s choice behaviour when selecting reach targets, suggesting the observer may extract the values and costs that the actor associates with the targets.