Manipulable objects and the dynamic representation of hand actions

运动表征构成了我们日常物品知识的一部分，比如计算器和喷雾罐。越来越多的证据表明，这些表征决定了我们持有和使用可操作物体的能力，在语言和感知任务中是动态调用的。例如，当观察者看到可抓取的物体时，空间注意力会以意想不到的方式发生变化。因此，高级运动系统在认知中所起的计算作用，以及在给定任务环境中决定特定手部表征的过程的本质，都是人们最感兴趣的。任何可操作的对象都提供一系列熟悉的动作。例如，我们学习拿起或移动一个袖珍计算器，用一个倒开的手握，但我们学习使用它的传统功能，用伸出的食指戳键盘。因此，我区分了体积抓握和功能性抓握，前者与物体的形状和重量属性有关，用于举起或移动，后者是当我们希望执行物体功能时引发的手部互动。我开发了一种新颖的实验方法来评估特定的手部动作表征对单词、物体或句子的实时唤起。这种方法要求受试者在一个八元素反应装置上进行快速到达和抓取动作。每个元素都提供一个独特的动作，主体学习根据视觉提示产生给定的手动动作。然后，我们测量一个物体、单词或句子（启动事件）对伸手和抓握表现的影响，时间锁定在视觉线索上，得出启动事件诱发的运动表征的性质和时间过程的证据。我描述了一系列旨在评估图像和单词的功能和体积把握表征的时间过程的实验。此外，我希望评估手部动作表征在对可操作对象的空间注意中的作用。这项研究提供了有价值的收敛方法，将澄清来自功能成像研究和神经心理学的证据。

Motor representations form part of our knowledge of everyday objects like calculators and spray-cans. There is increasing evidence that such representations, determining our ability to hold and use manipulable objects, are invoked dynamically during language and perceptual tasks. For example, spatial attention is modulated in unexpected ways when observers view graspable objects. The computational role played by higher level motor systems in cognition is therefore of fundamental interest, as is the nature of the processes that determine a particular hand representation in a given task context. Any manipulable object affords a range of familiar actions. For example, we learn to pick up or move a pocket calculator with an inverted open grasp, but we learn to use it according to its conventional function by poking the keys with an extended forefinger. I therefore distinguish between volumetric grasps, having to do with the shape and weight properties of an object for lifting or moving, and functional grasps, those hand interactions evoked when we wish to carry out an object's function. I have developed a novel experimental method to assess the evocation of specific hand action representations to words, objects or sentences in real time. This approach requires subjects to carry out speeded reach and grasp actions on an eight-element response apparatus. Each element affords a unique action and subjects learn to produce a given manual action in response to a visual cue. We then measure the influence of an object, word or sentence (a priming event) on reach and grasp performance, time-locked to the visual cue, yielding evidence on the nature and time course of the motor representations evoked by the priming event. I describe a series of experiments designed to assess the time course of functional and volumetric grasp representations for pictures and words. In addition, I wish to assess the role of hand action representations in spatial attention to manipulable objects. This research provides valuable convergent methods that will clarify evidence available from functional imaging research and from neuropsychology.