In 1992, Goodale and Milner proposed to study the visual system based on function, thus dissociating vision for perception (ventral stream) and vision for action (dorsal stream). This became known as the Perception and Action model (PAM). Following the PAM in the visual system, a somatosensory PAM was proposed including a body representation for perception and a separate for action. This review explores the body model of the hand and how it relates to the PAM. The body model refers to the internal representation of the body that is responsible for position sense. Previous research has shown that the representation of the hand features systematic distortions: an overestimation of hand width and an underestimation of finger length. These distortions have been reported using different paradigms, different body parts, and in various settings. Thus, body model distortions appear to be a characteristic of human body representation. If the body model of the hand is distorted, how can actions like reaching and grasping be accurate? We review evidence that body model distortions may in fact provide a functional benefit to our actions, that cortical maps in the somatosensory and motor cortices reflect these distortions, and that actions rely on a distorted body model. We argue that the body model is a product of both the ventral and dorsal somatosensory streams. Further, we suggest that the body model is an example of the inextricable link between the two streams.

中文翻译：

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感知、行动和身体模型

1992年，古代尔和米尔纳提出研究基于功能的视觉系统，从而将感知视觉（腹侧流）和行动视觉（背侧流）分离。这被称为感知和行动模型（PAM）。继视觉系统中的 PAM 之后，提出了体感 PAM，其中包括用于感知的身体表示和用于动作的单独表示。本综述探讨了手的身体模型及其与 PAM 的关系。身体模型是指负责位置感的身体的内部表示。先前的研究表明，手部的表征存在系统性扭曲：高估了手部宽度，低估了手指长度。这些扭曲已经在不同的范式、不同的身体部位和不同的环境中得到了报道。因此，身体模型扭曲似乎是人体表征的一个特征。如果手的身体模型扭曲了，伸手、抓握等动作怎么能准确呢？我们回顾了以下证据：身体模型扭曲实际上可能为我们的行为提供功能性益处，体感和运动皮质中的皮质图反映了这些扭曲，并且行为依赖于扭曲的身体模型。我们认为身体模型是腹侧和背侧体感流的产物。此外，我们认为身体模型是两个流之间密不可分的联系的一个例子。