Selection and Planning of Reach to Grasp Actions in the Presence of Competing Action Targets

在计划行动时，我们的环境中可能有许多对象可以与之交互。考虑和朋友共进午餐，你的水杯，你朋友的杯子，番茄酱瓶，盐瓶都可能是你行动的潜在目标。先前的研究表明，我们的伸手动作可以转向或远离环境中分散注意力的物品，在有分散注意力的物品时，我们需要更长的时间才能做出反应。然而，大多数研究都使用了指向动作。显然，我们经常需要抓住环境中的物体，但抓住可能会改变我们想要将手臂移动到物体上的方式。例如，你可以指着一个物体的任何地方，但你需要让你的手掌能够抓住它。本研究的主要目的是了解当我们的环境中有多个物体时，我们如何选择和计划抓取动作。拟议中的研究将使用特殊的摄像机来记录参与者如何在空间中移动他们的手臂，以及特殊的手套来记录一个人的手的形状。在所有的实验中，当另一个物体出现时，参与者必须伸手去抓住或指向物体。在第一个系列的实验中，参与者在开始动作之前会知道他们应该够到什么物体。我们预计他们的手臂路径会受到非目标物体的影响，特别是手掌同一侧的非目标物体。在另一系列实验中，参与者需要在知道目标在哪里之前就开始运动。只有当它们开始移动时，它们才会被提示哪个物体是目标。这模仿了我们在不确定的条件下或环境中信息变化时如何计划行动。我们希望参与者在不确定要移动到哪个物体时，能够计划开始他们的动作，这样他们的手掌就可以同时接触到两个潜在的物体。在最后的一系列实验中，参与者将看到两个不同大小的物体。他们必须在不知道哪个物体是目标的情况下开始移动。我们将检查他们张开手的大小和形状。在这一系列的实验中，我们还将建立一个模型，预测手在运动早期最终会形成什么样的抓握形状。这项拟议中的研究将为我们的大脑如何控制手臂和手的使用提供新的知识。预测抓取动作的模型可以应用于机器人和基于手势的界面。

When planning an action there can be many objects in our environment that we can interact with. Consider meeting a friend for lunch, your water glass, your friend's glass, the ketchup bottle, the salt shaker could all be potential targets for your action. Previous research has shown that our reaching movements can veer toward or away from distracting items in our environment and we take longer to react to reach to a target in the presence of distracting items. Most of these studies however, have used pointing movements. Clearly we often need to grasp objects in the environment, but grasping may change how we want to transport our arm to the object. For instance you can point anywhere on an object, but you need to make the palm of your hand available to the object to be able to grasp it. The main goal of the proposed research is to understand how we select and plan grasping actions when there are multiple objects in our environment. The proposed research will use special cameras that record how the participant is moving their arm through space, and special gloves that can record the shape of a person's hand. In all experiments, participants will have to reach to grasp or reach to point to objects when another object is present. In the first series of experiments, participants will know what object they are supposed to reach to before they start the movement. We expect that their arm path will be affected by the non-target objects, and in particular, by non-target objects that are on the same side of the palm. In another series of experiments participants will need to start their movement before they know where the target is. Only once they start their movement will they be cued to which object is the target. This mimics how we plan our actions under uncertain conditions or when information changes in our environment. We expect that participants will plan to start their movement so their palm is available to both potential objects when they are not sure what object they will have to move to. In a final series of experiments, participants will be presented with two differently sized objects. They will have to start their movement without knowing which object will be the target. We will examine how big they open their hand and in what shape. In this series of experiments we will also be building a model that predicts what grasping shape the hand will eventually make early in the movement. The proposed research will provide new knowledge on how our brain controls the use of our arm and our hand. The model that predicts grasping movements can have applications in robotics and gesture based interfaces.