Manipulable objects and the dynamic representation of hand actions

运动表象构成了我们对计算器和喷雾器等日常物品知识的一部分。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，是在语言和知觉任务中动态调用的。例如，当观察者看到可抓到的物体时，空间注意力会以意想不到的方式进行调节。因此，高级运动系统在认知中扮演的计算角色是基本感兴趣的，在给定的任务环境中决定特定手部表征的过程的性质也是如此。任何可操纵的对象都会提供一系列熟悉的动作。例如，我们学习用倒置的张开抓手拿起或移动袖珍计算器，但我们通过伸出食指拨动按键来学习按照它的常规功能使用它。因此，我区分了体积抓握和功能性抓握，前者与举起或移动的物体的形状和重量属性有关，后者是当我们希望实现物体的功能时所唤起的手的相互作用。我开发了一种新的实验方法来实时评估对单词、物体或句子的特定手部动作表征的唤起。这种方法要求受试者在八元反应装置上进行快速伸展和抓取动作。每个元素提供一个独特的动作，受试者学习根据视觉提示产生给定的手动动作。然后，我们测量了物体、单词或句子(启动事件)对视觉线索时间锁定的伸展和抓取性能的影响，得出了启动事件所唤起的运动表征的性质和时间进程的证据。我描述了一系列实验，旨在评估对图片和单词的功能性和体积抓取表征的时间进程。此外，我希望评估手部动作表征在空间注意可操纵物体中的作用。这项研究提供了有价值的融合方法，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.