Longo Matthew R
Department of Psychological Sciences, Birkbeck, University of London, Malet Street, London, WC1E 7HX, UK.
Exp Brain Res. 2018 Nov;236(11):3113-3119. doi: 10.1007/s00221-018-5360-x. Epub 2018 Aug 21.
Perceiving the external spatial location of body parts using position sense requires that immediate proprioceptive afferent signals be integrated with information about body size and shape. Longo and Haggard (Proc Natl Acad Sci 107:11727-11732, 2010) developed a method to measure perceptual hand maps reflecting this metric information about body size and shape. In this paradigm, participants indicate the perceived location of landmarks on their occluded hand by pointing with a long baton held in their other hand. By comparing the relative location of judgments of different hand landmarks, perceptual hand maps can be constructed and compared to actual hand structure. The maps show large and highly stereotyped distortions. Here, I investigated the potential effect of biases related to active motor control of the hand doing the pointing in these distortions. Participants localized the fingertip and knuckle of each finger on their occluded left hand either by actively pointing with a baton held in their right hand (pointing condition) or by giving verbal commands to an experimenter on how to move the baton (verbal condition). Similar distortions were clearly apparent in both conditions, suggesting that they are not an artifact of motor control biases related to the pointing hand.
利用位置感来感知身体部位的外部空间位置，需要将即时的本体感觉传入信号与有关身体大小和形状的信息进行整合。隆戈和哈格德（《美国国家科学院院刊》107:11727 - 11732，2010年）开发了一种方法来测量反映这种关于身体大小和形状的度量信息的感知手部地图。在这个范式中，参与者用另一只手持的长棍指向被遮挡手部上地标点的感知位置。通过比较不同手部地标点判断的相对位置，可以构建感知手部地图并与实际手部结构进行比较。这些地图显示出巨大且高度刻板的扭曲。在此，我研究了在这些扭曲中与进行指向操作的手部的主动运动控制相关的偏差的潜在影响。参与者通过用右手持棍主动指向（指向条件）或向实验者给出关于如何移动棍子的口头指令（口头条件）来定位被遮挡左手每个手指的指尖和指关节。在两种条件下都明显出现了类似的扭曲，这表明它们不是与指向手相关的运动控制偏差的人为产物。
