Institute of Cognitive Neuroscience, University College London, London WC1N 3AR, United Kingdom.
Proc Natl Acad Sci U S A. 2010 Jun 29;107(26):11727-32. doi: 10.1073/pnas.1003483107. Epub 2010 Jun 14.
Knowing the body's location in external space is a fundamental perceptual task. Perceiving the location of body parts through proprioception requires that information about the angles of each joint (i.e., body posture) be combined with information about the size and shape of the body segments between joints. Although information about body posture is specified by on-line afferent signals, no sensory signals are directly informative about body size and shape. Thus, human position sense must refer to a stored body model of the body's metric properties, such as body part size and shape. The need for such a model has long been recognized; however, the properties of this model have never been systematically investigated. We developed a technique to isolate and measure this body model. Participants judged the location in external space of 10 landmarks on the hand. By analyzing the internal configuration of the locations of these points, we produced implicit maps of the mental representation of hand size and shape. We show that this part of the body model is massively distorted, in a reliable and characteristic fashion, featuring shortened fingers and broadened hands. Intriguingly, these distortions appear to retain several characteristics of primary somatosensory representations, such as the Penfield homunculus.
了解身体在外部空间中的位置是一项基本的感知任务。通过本体感觉来感知身体部位的位置需要将每个关节的角度信息（即身体姿势）与关节之间的身体部位的大小和形状信息结合起来。虽然有关身体姿势的信息是由在线传入信号指定的，但没有任何感觉信号可以直接提供关于身体大小和形状的信息。因此，人类的位置感必须参考身体的度量属性（例如身体部位的大小和形状）的存储身体模型。人们早就认识到了这种模型的必要性；但是，该模型的特性从未得到系统的研究。我们开发了一种技术来隔离和测量这种身体模型。参与者判断了手上 10 个地标在外部空间中的位置。通过分析这些点的位置的内部结构，我们生成了手部大小和形状的心理代表的内隐图。我们表明，该身体模型的这一部分以可靠且特征的方式严重变形，具有缩短的手指和变宽的手。有趣的是，这些扭曲似乎保留了一些主要体感代表的特征，例如彭菲尔德小人。
