Manipulable objects and the dynamic representation of hand actions

运动表征构成了我们对计算器和喷雾罐等日常物品的知识的一部分。 越来越多的证据表明，这种表征决定了我们持有和使用可操纵物体的能力，在语言和感知任务中被动态调用。 例如，当观察者看到可抓取的物体时，空间注意力以意想不到的方式被调制。 因此，高级运动系统在认知中所扮演的计算角色具有根本意义，因为在给定的任务背景下，确定特定手部表征的过程的性质也是如此。 任何可操纵的物体都提供一系列熟悉的动作。 例如，我们学习用倒置的开放式抓握来拿起或移动袖珍计算器，但我们学习用伸出的食指戳键来根据其常规功能使用它。 因此，我区分体积抓持，与物体的形状和重量属性有关的提升或移动，和功能性抓持，当我们希望执行物体的功能时，这些手的相互作用。 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在真实的时间内对单词、物体或句子的唤起。 这种方法要求受试者在八元件反应装置上进行快速到达和抓握动作。 每个元素都提供了一个独特的动作，受试者学习根据视觉提示产生一个给定的手动动作。 然后，我们测量的影响，一个对象，单词或句子（启动事件）达到和把握性能，时间锁定的视觉线索，产生的证据的性质和时间过程中引起的启动事件的电机表示。 我描述了一系列的实验，旨在评估的时间过程中的功能和体积把握表示的图片和文字。 此外，我希望评估手的动作表征的作用，在空间注意到可操纵的对象。 这项研究提供了有价值的收敛方法，将澄清从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.