Kammers M P M, de Vignemont F, Verhagen L, Dijkerman H C
Utrecht University, Heidelberglaan 2, 3584 CS Utrecht, The Netherlands.
Neuropsychologia. 2009 Jan;47(1):204-11. doi: 10.1016/j.neuropsychologia.2008.07.028. Epub 2008 Aug 9.
In the well-known rubber hand illusion (RHI), watching a rubber hand being stroked while one's own unseen hand is synchronously stroked, induces a relocation of the sensed position of one's own hand towards the rubber hand [Botvinick, M., & Cohen, J. (1998). Rubber hands 'feel' touch that eyes see. Nature, 391(6669), 756]. As one has lost the veridical location of one's hand, one should not be able to correctly guide one's hand movements. An accurate representation of the location of body parts is indeed a necessary pre-requisite for any correct motor command [Graziano, M. S. A., & Botvinick, M. M. (1999). How the brain represents the body: Insights from neurophysiology and psychology. In D. Gopher, & A. Koriat (Eds.), Attention and performance XVII-Cognitive regulation of performance interaction of theory and application (pp. 136-157)]. However, it has not yet been investigated whether action is indeed affected by the proprioceptive drift towards the rubber hand, nor has the resistance of visual capture in the RHI to new proprioceptive information been assessed. In the present two kinematic experiments, we show for the first time that action resists the RHI and that the RHI resists action. In other words, we show a dissociation between illusion-insensitive ballistic motor responses and illusion-sensitive perceptual bodily judgments. Moreover, the stimulated hand was judged closer to the rubber hand for the perceptual responses, even after active movements. This challenges the view that any proprioceptive update through active movement of the stimulated hand erases the illusion. These results expand the knowledge about representations of the body in the healthy brain, and are in line with the currently most used dissociation between two types of body representations so far mainly based on neuropsychological patients [Paillard, J. (1991). Knowing where and knowing how to get there. In J. Paillard (Ed.), Brain and space (pp. 461-481); Paillard, J. (1999). Body schema and body image: A double dissociation in deafferented patients. In G. N. Gantchev, S. Mori, & J.Massion (Eds.), Motor control, today and tomorrow (pp. 197-214)].
在著名的橡胶手错觉（RHI）实验中，当人们看不到自己的手时，看着一只橡胶手被抚摸，同时自己的手也被同步抚摸，会导致人们感觉到自己手的位置向橡胶手偏移[博特维尼克，M.，& 科恩，J.（1998）。橡胶手“感觉”到眼睛看到的触摸。《自然》，391(6669)，756]。由于人们失去了自己手的真实位置，应该无法正确引导手部动作。身体部位位置的准确表征确实是任何正确运动指令的必要前提[格拉齐亚诺，M. S. A.，& 博特维尼克，M. M.（1999）。大脑如何表征身体：来自神经生理学和心理学的见解。载于D. 戈弗，& A. 科里亚特（编），《注意力与表现XVII——表现的认知调节：理论与应用的相互作用》（第136 - 157页）]。然而，尚未研究动作是否真的会受到向橡胶手的本体感觉漂移的影响，也未评估RHI中视觉捕获对新本体感觉信息的抵抗力。在目前的两个运动学实验中，我们首次表明动作能抵抗RHI，且RHI也能抵抗动作。换句话说，我们展示了错觉不敏感的弹道式运动反应与错觉敏感的感知身体判断之间的分离。此外，即使在主动运动之后，对于感知反应而言，被刺激的手仍被判断为更靠近橡胶手。这对通过被刺激手的主动运动进行任何本体感觉更新会消除错觉这一观点提出了挑战。这些结果扩展了关于健康大脑中身体表征的知识，并且与目前主要基于神经心理学患者的两种身体表征之间最常用的分离观点一致[帕亚尔，J.（1991）。知道位置和知道如何到达那里。载于J. 帕亚尔（编），《大脑与空间》（第461 - 481页）；帕亚尔，J.（1999）。身体图式与身体意象：去传入患者中的双重分离。载于G. N. 甘切夫，S. 森，& J. 马西翁（编），《运动控制，今日与明日》（第197 - 214页）]。
