Decision making in action planning and control

现实世界的行动任务涉及一系列决策过程，这些决策过程基于展开任务期间提取的信息，决定下一步采取何种行动以及何时采取行动。然而，对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。这项拟议研究的主要目的是通过调查人类目标导向到达任务背景下的决策过程，更好地理解大脑是如何控制行动的。拟议的研究包括四个相互关联的项目。虽然大多数关于伸手的研究都集中在针对单个目标的动作上，但在现实世界中，我们经常面临多个潜在的动作目标。项目一的目的是研究在这些目标不确定的条件下，大脑是如何准备一个到达运动的。最近的研究表明，在到达准备过程中，大脑会对多个潜在目标进行编码，并且在指定目标之前启动的到达的初始方向会受到潜在目标分布的影响。这些结果与为潜在目标准备了多个到达计划的想法是一致的，但也与在目标不确定的情况下，人们在战略方向上计划单个到达的概念是一致的。我们将在这些选择之间进行严格的测试。许多自然任务涉及在每一步从备选目标中选择一系列目标，最优觅食理论为研究与不同目标或目标序列相关的奖励和成本如何影响目标选择行为提供了一个自然框架。虽然有少数研究考察了价值和成本如何影响单个目标的选择，但据我们所知，没有研究调查了顺序目标的选择。项目2将使用我们最近开发的运动觅食任务来研究与顺序目标选择相关的决策。基于对学习的成本和回报的评估，人们经常面临是否值得投资学习一项新技能的决定。然而，据我们所知，这种与技能学习相关的决策尚未得到定量研究。项目3将研究学习和奖励优化之间的相互作用，使用到达任务，参与者可以选择是否从事运动学习，这将最终使他们获得更高价值的奖励。一个关键的目标是评估参与者利用自己学习新技能的能力来做出是否投资于这种学习的正确决定的能力。对行动观察的研究表明，观察者会提取行为人目标的信息。然而，在观察涉及决策的行动任务时，没有研究检验过观察者是否提取了指导行动者做出选择的潜在有价值的信息。我们之前已经证明，观察者一旦能够预测到目标，就会将目光转向演员动作的目标。在PROJECT 4中，我们将记录观察者的眼球运动，以测试他们是否学会了预测演员在选择到达目标时的选择行为，这表明观察者可能会提取演员与目标相关的价值和成本。

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.