心理科学进展, 2019, 27(1): 37-50 doi: 10.3724/SP.J.1042.2019.00037

研究前沿

橡胶手错觉:拥有感研究的实验范式及其应用

赵佩琼1, 陈巍,1,2, 张静,3, 平贤洁2

1 绍兴文理学院社会行为与发展科学研究中心

2 绍兴文理学院心理学系, 绍兴 312000

3 杭州电子科技大学心理健康研究所, 杭州 310018

The rubber hand illusion (RHI): The experimental paradigm of sense of ownership and its application

ZHAO Peiqiong1, CHEN Wei,1,2, ZHANG Jing,3, PING Xianjie2

1 Center for Social Behavior and Developmental Science, Shaoxing University, Shaoxing 312000, China

2 Department of Psychology, Shaoxing University, Shaoxing 312000, China

3 Institute of Psychological Health, Hangzhou Dianzi University, Hangzhou 310018, China

通讯作者: 陈巍, E-mail: anti-monist@163.com张静, E-mail: jingzhanghz@163.com

收稿日期: 2018-05-11   网络出版日期: 2019-01-15

基金资助: * 国家社科基金青年项目.  16CZX015
教育部人文社会科学研究青年基金.  17YJCZH243
浙江省大学生科技创新活动计划暨新苗人才计划项目.  2017R4280 18

Received: 2018-05-11   Online: 2019-01-15

摘要

橡胶手错觉是一种健康个体将非肉体的假手视为自己真实身体的一部分的体验, 这种错觉可以通过同时轻刷被试面前可见的橡胶手及其不可见的真手而产生.橡胶手错觉已成为一种研究身体拥有感的重要范式, 其产生机制可以分为“自下而上的认知匹配”与“自上而下的认知匹配”两种加工方式.前者涉及视觉与触觉刺激的同步性; 而后者涉及被试心中预存的身体意象与身体图式(包括真假手之间模态特征,位置空间的相似性).综合上述证据, 身体模型假说与个人边缘空间理论进一步为拥有感产生的复杂机制提供了整合两种加工方式的解释.橡胶手错觉范式已经被用于探索精神分裂症患者等特殊被试病理分析,错觉产生和心理特质之间的关系, 以及神经外科和术后恢复上.未来的研究应该更加重视范式本身的拓展, 应用虚拟现实技术来提高身体模态的仿真效果, 利用橡胶手拥有感的易感性作为筛选与预测身体意象障碍疾病的指标.

关键词: 身体自我 ; 橡胶手错觉 ; 拥有感 ; 自主感 ; 本体感觉 ; 多感觉整合 ; 虚拟现实

Abstract

The rubber hand illusion is a perceptual illusion in which participants experience a fake model hand as part of their own body. Such an illusion could be induced by applying synchronous touches to a visible rubber hand and the hidden real hand. Rubber hand illusion has become an important paradigm of bodily sense of ownership, whose mechanism can be further divided into “bottom-up matching” and “top-down matching”. The former refers to the synchronicity of visual and tactile stimulations, while the latter refers to the participants’ pre-existed body image and body schema (including the modality of real and fake hand, similarity of spatial position). Based on above, body model theory and peri-personal space (PPS) have been proposed to explain the integration of two matching mechanisms of the arouse of body ownership. Rubber hand illusion is used to the exploration of the pathological analysis of schizophrenia, the relationship between illusion and psychological traits, the application in neurosurgery and postoperative recovery. Future studies should pay more attention to the development of paradigm itself, the enhancement of simulated effect by using virtual reality technology, as well as using the sensibility of sense of ownership to filter and predict body image related diseases.

Keywords: bodily self ; the rubber hand illusion (RHI) ; sense of ownership ; sense of agency ; proprioception ; multisensory integration ; virtual reality

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本文引用格式

赵佩琼, 陈巍, 张静, 平贤洁. (2019). 橡胶手错觉:拥有感研究的实验范式及其应用 . 心理科学进展, 27(1), 37-50

ZHAO Peiqiong, CHEN Wei, ZHANG Jing, PING Xianjie. (2019). The rubber hand illusion (RHI): The experimental paradigm of sense of ownership and its application. Advances in Psychological Science, 27(1), 37-50

当手指交叉(触摸一个物体)时, 一个物体似乎变成了两个, 但我们否认这是两个物体, 因为视觉比触觉更权威.然而, 如果触觉是独立的, 我们实际上应该将一个物体宣称为两个.

——Aristotle, 公元前384-322

1 引言

从亚里士多德时代到William James的《心理学原理》, 再到Gibson的知觉心理学理论, 众多的心理现象及其解释不断向我们揭示这样一个事实:身体可能是我们最为熟悉的对象, 我们不仅不断地通过它接收外部信息, 而且还有通达它的内部通道.伴随以具身认知(embodied cognition)运动为代表的第二代认知科学(second-generation cognitive science)的不断推进, 研究者越来越不满

于从实验或理论上关注“身体如何因果性地影响认知活动”以及“身体是理解认知的必要条件”等等主题(Glenberg, Witt, & Metcalfe, 2013).近期, 融合第一人称(first-person)与第三人称(third- person)的视角来考察具身主体(embodied subject)的体验或“具身感” (the sense of embodiment) (Carruthers, 2015)吸引了更多心智哲学家,心理学家,认知科学家,神经科学家的目光(周爱保 等, 2013; Braun et al., 2018).有学者指出, 如果没有具身体验的身体自我(bodily self)或身体自我觉知(bodily self-awareness), 个体很难能感受到自身的心智活动, 而正是这种体验促进了对自我的知觉, 进而有助于自我意识的发展(Balconi & Bortolotti, 2010).同时, 身体自我涉及到的本体感觉(proprioception)与内感受(interoception)对自我意识来说也是最基本的, 能够保证将自我和他人区分开来, 这构成了社会认知的核心(Palmer & Tsakiris, 2018).在认知神经科学共同体中, 研究者对理解身体进行表征时涉及的心理过程,以及这些过程如何在脑中执行等问题的研究兴趣与日俱增(Jackson, Buxbaum, & Coslett, 2011).

身体的拥有感(sense of ownership)和自主感(sense of agency)是目前身体自我研究的两个热门主题(Braun et al., 2018).拥有感是指我感觉到自己的身体及其运动, 或者我作为运动的主体的前反思经验或感觉(例如, 那种我在控制我的动作的经验) (Gallagher, 2000).拥有感作为自我表征的一种形式, 被认为包含三个层次的内容:拥有性的感受(feeling of ownership),拥有性的判断(judgement of ownership),拥有性的元表征(meta- representation of ownership) (Synofzik, Vosgerau, & Newen, 2008), 与之有着紧密联系并且在一般体验中难以与之分离的是自主感, 它是指某人正在发起,执行,并控制其自身在世界中的意志行动的主观的觉知(Jeannerod, 2003).即前者是一种个体将自己的身体及其运动归属于“我”的感觉, 而后者是一种“我”作为行动发起者的感觉(de Vignemont, 2011).在正常情况下, 这两种感觉是不可分离的, 但是在某些特殊的人群, 如精神分裂症患者身上又能够经常观察到两者的不协调.例如, 病人经常会抱怨某些在他人看来由其本人发起或做出的动作并不受其主观意愿控制.

此外, 更能说明问题的当属Sørensen (2005)设计的异己手实验(the alien-hand experiment).在实验中, 被试的任务是通过一个箱子上的小窗口观察自己戴着手套的手的运动, 并同时完成一项看似简单的任务:画一条与已经呈现在纸上的直线平行的直线.实验中, 被试未被告知的是, 他们面前的箱子并不是看上去的那么简单.箱子里有一面镜子, 通过这个巧妙的设计, 实验者可以让被试以为他们看到的是自己手的运动, 而实际上呈现在他们视线范围内的是实验者的手的运动.因此, 在实验过程中, 被试会不止一次地发现, 简单的画直线的任务会变得出人意料的困难.他们几乎毫无疑问地肯定看到的手是属于自己的, 但是他们却不可避免地产生类似于无法对自己的手进行控制的怀疑:“我没有停, 不过我与自己的手失去了联系, 手在做它喜欢做的, 而我对此无能为力.”造成拥有感与自主感分离的原因是:在执行任务的过程中, 被试的动作意图提醒其在箱内镜子下面向前移动的就是自己的手, 但视觉输入却“否决”了动作意图试图保留的本体感觉信息(proprioceptive information).最终, 被试直接经验到作为“对我”发生的运动(拥有感), 而没有体验到作为“由我”产生的运动(自主感).不难看出, 较之自主感, 拥有感更具有“奠基” (fundierung)意义(陈巍, 郭本禹, 2012).而且, 对身体的识别对于成为一个有意识的自我而言至关重要(Suzuki, Garfinkel, Critchley, & Seth, 2013).目前, 与身体有关的认知科学问题主要也集中在拥有感上, 如:拥有感的基础是什么?拥有感的功能角色是什么?拥有感如何与身体的感觉,动作以及情感相联系?一个人能对其它的非身体的对象感受到拥有感吗?(de Vignemont, 2011)

从最近几年的研究趋势上也能看出拥有感日益凸显的重要性.在Web of Science上以拥有感(sense of ownership)为主题词进行检索, 结果如图1所示.从中可以直观地看到近年来以拥有感为主题的研究在数量与影响上的激增.

图1

图1   拥有感的研究现状


目前, 对于拥有感的研究主要集中在两个方面:(1)将一个外部对象体验为某人自己身体一部分的具身性研究; (2)通过对病人体验到身体的一个部分不是自己的缺失的研究(de Vignemont, 2011).较之只能在少数病理性的特殊被试身上开展的后者, 前者显然更为方便与经济.就此而言, 新的方法与研究方式的引入仍将对该领域的研究产生深远的影响与积极的推动作用(Ionta et al., 2011; 周爱保 等, 2013; Christ & Reiner, 2014).橡胶手错觉范式便是不可不提的工作.

2 拥有感研究的橡胶手错觉范式

1998年, Botvinick与Cohen在《自然》上发表的一篇占幅仅一页的实验报告将橡胶手错觉(Rubber Hand Illusion, RHI)这一奇妙的实验范式呈现在了大家面前(Botvinick & Cohen, 1998), 从此也为身体拥有感的研究提供了一种新范式.橡胶手错觉是一种将人造的身体部分感受为自己真实身体的一部分的体验, 实验中通常采用的是人造手.最初的橡胶手错觉包括两个实验.在第一个实验中, 被试坐在一张桌子前, 左胳膊置于桌面上.将一块竖立的挡板置于被试的视线和左胳膊之间, 使得被试无法直接看到自己的左手.将一只人造的与橡皮仿真手置于被试面前的桌面上, 用一块布将被试的左侧肩膀至橡胶手腕部分遮挡起来, 以便让被试能够直视面前的橡胶手而无法看到自己置于挡板左侧的真实手(如图2所示).用两把刷子尽可能同时地轻刷被试被隐藏的左手和他视线内的橡胶手.10分钟之后结束实验, 要求被试完成一份包含9个问题的问卷.结果显示他们感受到的触感不是来自视线外的真正施加在自己真实手上的刷子, 而是源自眼前所能看到的与橡胶手接触的刷子.即, 第一个实验说明了被试通过这种方式产生了一种拥有感的错觉.

图2

图2   经典橡胶手错觉实验示意图


在第二个实验中, Botvinick和Cohen把被试的眼睛蒙上, 并要求被试将他们的右手食指放到与看不见的左手食指对齐的位置(左手仍置于与第一个实验中相同的位置).结果显示被试右手食指所放置的位置会趋于橡胶手对应的位置, 第一个实验持续的时间越久这种偏移就越明显.这一实验中观察到的现象与结果得到了很多研究者的重复与证实, 并在各种不同的条件下得到了验证.Armel和Ramachandran采用皮肤电传导技术(skin conductance responses, SCR)发现当有威胁直接作用于橡胶手上时会有人体内的电流会升高, 说明在人造手上产生了一种“情感反应” (affective resonance)与“情绪卷入” (emotional involvement) (Armel & Ramachandran, 2003).

尽管对于橡胶手错觉现象产生的原因, 至今仍未有权威的共识, 但很多研究者基本都同意橡胶手错觉与视觉,触觉以及本体感觉间的匹配与交互作用有关.Paladino等通过实验证明了同步的多感官刺激会导致自我-他者的融合, 存在时间上的一致性(self-other merging) (Paladino, Mazzurega, Pavani, & Schubert, 2010), 也存在跨情景的一致性(Bekrater-Bodmann, Foell, Diers, & Flor, 2012),跨年龄的一致性(Campos, Richandi, Taati, & Keshavarz, 2018).在橡胶手错觉中, 中央神经系统将外部对象即橡胶手归类为身体的一部分(Haans, Kaiser, Bouwhuis, & IJsselsteijn, 2012).作为这种身体意象基础的认知和感觉运动机制将包括视觉与触觉的整合与身体特定的感觉运动意外事件的发现进行合并(Botvinick, 2004).不同感觉输入的结合均能够产生拥有感错觉, 在主动运动,被动运动和视触刺激三种条件下, 发现了同样强度的橡胶手错觉(Kalckert & Ehrsson, 2017; Kalckert & Ehrsson, 2014), 用二维的假手和三维假手在皮肤电测试和行为数据上都得出同样的结果(Pasqualotto & Proulx, 2015).利手和非利手在主客上均能产生同样的橡胶手错觉(Smit, Kooistra, van der Ham, & Dijkerman, 2017), 运动对产生和保持连贯的拥有感起一定作用(Burin et al., 2015), Abdulkarim等人指出橡胶手错觉实验中, 被试手的主动运动能够对手的位置产生更大的校准, 这种空间位置的校准是基于错误的感觉运动矫正, 与感觉肢体位置校准的知觉机制有关(Abdulkarim & Ehrsson, 2018).同时错觉的强度似乎会受到橡胶手形状与真实人手相似程度的内部模型的调节, 形态上与人类身体差异较大的较难得到整合从而也更不容易产生错觉, 即要求真假手之间存在匹配程度的一致性, 即橡胶手错觉产生的模态(modality)一致性(Knoblich, Thornton, Grosjean, & Shiffrar, 2006; Riemer et al., 2014).工具的一致性, 如果触摸橡胶手和真手的工具不同, 同样影响错觉产生(Ward, Mensah & Jünemann, 2015).错觉的强度会随着橡胶手离解剖学上可能的手的位置的距离的增加呈现非线性的下降, 体现了橡胶手错觉产生的特征一致性(Lloyd, 2007).此外, 使用橡胶手错觉的范式, 对双脚进行错觉测试, 发现在同步刷的情况下, 只要是在合适的力度下, 同样会有错觉产生, 称为橡胶足错觉(rubber foot illusion) (Flögel, Kalveram, Christ, & Vogt, 2016).橡胶手错觉的这些特点也为此使其成为身体拥有感研究的重要方法.

3 利用橡胶手错觉范式探索拥有感产生的认知与神经机制

为什么人们会对这样一只不属于自己身体的一部分甚至不和自己身体有任何接触的橡胶手产生错误的拥有感?自橡胶手错觉范式被报告以来, 这一问题一直困扰着研究者们.对于Botvinick与Cohen最初将橡胶手错觉归因为视觉,错觉以及本体感觉之间的交互作用, 但这种笼统的解释显然不足以解答所有的疑问.橡胶手错觉实验设计过程中涉及两个关键点, 即橡胶手的形状,特性及其与真手之间的关系.大多数学者都认同前者涉及自下而上的认知匹配, 即刷子的同步性等; 而后者则涉及自上而下的认知匹配, 即被试心中预存的身体意象与身体图式.包括真假手之间模态特征,位置空间的相似性.然而, 至今为止的实验证据显示, 这两种加工方式都有其合理性, 并有可能同时存在(Carruthers, 2013; Braun et al., 2018; Palmer & Tsakiris, 2018).

3.1 自下而上的匹配(bottom-up matching)

Armel和Ramachandran将经典橡胶手错觉中的假手换成光秃秃的桌面, 同时用刷子刷被试被隐藏的真手和面前的桌面, 并在一定时间之后向桌面施加潜在的疼痛刺激(Armel & Ramachandran, 2003).实验以皮肤电反应作为因变量指标来考察被试的拥有感错觉体验.与橡胶手错觉中类似的拥有感错觉在他们的实验过程中同样存在.此外, 他们还对橡胶手的位置进行了调整, 当橡胶手被移至距离真手3英寸的位置时, 拥有感错觉也依然存在.因此, 他们认为拥有感错觉的出现主要依赖于视觉和触觉刺激的同步性.与此结果类似, Ma和Hommel (2015)发现被试对虚拟的木块和气球同样产生了拥有感.并且, 他们进一步解释拥有感错觉中的这种“自下而上的匹配”机制是贝叶斯知觉学习(Bayesian perceptual learning)过程.通过这一过程, 不同模态的两种知觉过程如果恰巧同时发生它们就能被“联结” (bound)起来.换言之, “被看见的”和“被感到的”触摸之所以被“联结”在一起就是因为它们时间上的同步性.功能性磁共振成像(functional magnetic resonance imaging, fMRI)发现腹侧前运动皮层(ventral premotor cortex, VPC)在拥有感的产生过程中, 视触刺激融合起着至关重要的作用(Bekrater-Bodmann et al., 2012; Ehrsson, Spence, & Passingham, 2004; Lee & Chae, 2016).同样的证据来自于Guterstam等人发现, 即使同步刷被试的身体和空气, 被试能对空气产生拥有感(Guterstam, Abdulkarim, & Ehrsson, 2015), Guterstam等通过运动追踪,多重行为测试发现, 尽管刷子和橡胶手存在一定的距离, 但是如果同时在半空中(不直接接触)刷橡胶手和隐藏的真手, 就会产生一种“磁力”, 能够让被试感受到“磁力”触碰的错觉, 进而产生橡胶手错觉(Guterstam, Zeberg, Özçiftci, & Ehrsson, 2016), 对身体拥有感之间的神经关联进行研究发现, 同步模仿确实能产生对假臂的拥有感, 但是真实手臂的拥有感及对假臂的拥有感之间大脑反应是不同的, 对真实手臂的拥有感程度激活腹内侧前额皮层, 侧枕颞皮层, 而不是颞顶叶皮层.相反, 同步模仿情况下腹侧前皮层激活程度比不同步模仿和真实手臂更高(Limanowski & Blankenburg, 2016).

最近的一项研究使用虚拟手错觉实验, 以猫爪作为虚拟手对象, 把抓住硬币和躲避刀片作为实验任务, 测试被试的焦虑感, 发现被试在同步条件下比不同步条件产生了更强烈的焦虑感(Chen, Zhang, Qian, & Gao, 2017).同步性对拥有感存在一定程度的影响也为自下而上的匹配提供了证据.进一步的, 张静和陈巍(2016)的实验引入距离参照系, 考察了不同参照条件下被试对同一个位置的虚拟手在不同同步情况下的拥有感错觉.研究结果发现:(1)无论是同步性还是距离都会对虚拟手错觉中的拥有感产生影响, 即同步比不同步条件下,距离近比距离远条件下拥有感显著; (2)不同的距离参照系对同一位置的拥有感体验影响差异显著, 先近后远的呈现方式会减弱错觉而先远后近的呈现方式则会加强错觉.这一发现与身体拥有感是受稳定的身体意象调节的假设并不一致.以上结果都表明, 身体意向是可塑的, 个体拥有感的产生并不依赖于身体意向, 或者身体意向会随着输入信息对个体的身体意向随时进行修改.

但是, 除了同步性以外, 其它的特性就都不重要吗?根据贝叶斯知觉学习理论可以预测, 被试看到的对象不管是类似于身体的一部分还是仅仅只是中性的对象都无关紧要, 只要视觉和触觉刺激的同步性存在即可.显然, 认为自上而下的知觉匹配才是错觉产生关键的研究者并不这么认为.

3.2 自上而下的匹配(up-bottom matching)

Tsakiris和Haggard设计了这样一个实验:他们将被试所看到的橡胶手进行位置的旋转, 让橡胶手的位置从与真手一致的角度开始顺时针旋转90°, 或者干脆直接用木棒或对侧手替换掉橡胶手, 他们用经典橡胶手实验中真手对于假手的本体感觉的偏移(proprioceptive drift)作为因变量指标考察错觉的强度, 实验结果表明, 拥有感错觉的强度出现了显著的下降(Tsakiris & Haggard, 2005).近期, 有研究使用虚拟现实技术发现, 在屏幕上呈现的3D假手也可以诱发橡胶手错觉(Ma & Hommel, 2013).和Tsakiris和Haggard的试验相类似, Masakazu发现假手旋转0°,45°,90°和315°时产生的错觉强于180°,225°和270°, 研究者认为这是因为前四种旋转角度更具解剖学上的合理性(anatomical plausibility) (Ide, 2013).尽管对于两个实验中不同的因变量指标何者更为合适与客观的争论依旧存在, 但是Tsakiris和Haggard的实验已经很有说服力地挑战了Armel和Ramachandran所给出的解释.近期有研究者利用多通道脑电技术(multichannel EEG), 研究者设计了三种条件记录刷子刷被试左右手时产生的EEG信号, 没有假橡胶手(real),同步刷符合解剖学位置的假手(congruent),解剖学上不可能位置的假手(incongruent), 结果发现能够产生橡胶手错觉的条件(congruent)与不能产生错觉的条件(incongruent and real)产生的神经机制是不同的, 能够真实的感知到假手存在的条件下(incongruent)和其他两种条件也存在神经反应的差异, 研究者认为这可能是对有争议的多感觉信息输入时, 体感准确性下降了, 也是对错觉产生的自上而下机制的支持(Zeller, Litvak, Friston, & Classen, 2015).无论如何, 手的形状的对象会比非手的形状的对象产生更强的错觉, 对于皮肤纹理亦是如此(Haans, IJsselsteijn, & de Kort, 2008; Schütz- Bosbach, Tausche, & Weiss, 2009).同时也有研究表明, 橡胶手相对真手的大小也会影响橡胶手错觉的出现, 这种现象被称为“肢体大小效应(body size effect)” (van der Hoort, Guterstam, & Ehrsson, 2011).以上研究结果说明自上而下的认知会影响橡胶手错觉而使其对视知觉的需求比对触觉感觉的需求更大.此外, 从内隐启动实验证实对黑人偏见的存在也为自上而下的机制提供了支持, 以白人为被试, 进行橡胶手错觉实验发现相较于白人橡胶手, 对黑人橡胶手产生较小的错觉,错觉产生所需时间较长,本体感觉偏移量小(Lira et al., 2017).

3.3 “自下而上”和“自上而下”加工机制的整合

综上, 对于橡胶手错觉的产生而言, 尽管“自下而上”机制中视觉和触觉加工至关重要, 但“自上而下”机制中所涉及的更高级的认知过程的匹配可能也是不可或缺的.基于这样的认识, 一些学者尝试提出整合两种加工机制的理论模型.

Tsakiris提出了身体模型假说(body-model)的神经认知模型, 就是对上述两种加工机制的整合, 他认为身体拥有感是作为当前的多感官输入与身体的内部模型之间的交互作用而产生的.首先, 一个预先存在的身体模型会对可能是或不是某人身体一部分的对象进行识别.其次, 在线的(on-line)身体的结构表征和姿势表征会对多感官信息的整合进行调节, 而这种调节会导致视觉和触觉坐标系统的再校准.第三, 触觉感觉的最终参照会引起身体拥有感的主观体验.这些过程涉及一系列的神经网络, 包括负责对外部对象的不相似性进行检测的右颞顶联结(right temporoparietal junction, rTPJ),保持对身体的在线表征的次级躯体感觉皮层(somatosensory cortex),对围绕手的坐标系统的再校准进行编码的后顶叶(posterior parietal)和腹侧前运动皮层(ventral premotor)以及作为身体拥有感的主观体验基础的右后侧岛叶(right posterior insula).Tsakiris认为拥有感是会受到他称之为的身体模型的限制(Tsakiris, 2010).

认知神经研究结果得到了类似的结果, 如正电子断层扫描成像(positron emission tomography, PET)证实, 皮层的多感官区域, 如前运动皮层,上顶叶(superior parietal lobule)以及岛盖(operculum), 似乎对诱发橡胶手的拥有感错觉而言是关键区域, 而右侧脑岛, 可能还有额叶岛盖(frontal operculum)似乎关系到随后拥有感的产生(Tsakiris, Hesse, Boy, Haggard, & Fink, 2006).Olivé等人使用核磁共振技术发现错觉的产生与右侧颞顶联结处,中央后回(bilateral post central gyrus)有关(Olivé, Tempelmann, Berthoz, & Heinze, 2015).近期的脑电(electroencephalogram, EEG) 研究进一步揭示, 橡胶手错觉产生的过程中, 电信号先出现于对侧的运动皮层(motorcortex)和次级躯体感觉皮层, 之后传至顶叶(Zeller et al., 2015).Arizono等人使用近红外光谱技术(near-infrared spectroscopy, NIRS)发现相比较于没有产生橡胶手错觉, 错觉产生时氧血红蛋白的含量在右侧额叶和右侧运动皮层达到峰值, 并发现二者在错觉产生中存在功能性的联结(Arizono, Ohmura, Yano, & Kondo, 2016).

此外, 对中风病人的脑损伤研究也表明, 腹侧前运动皮层在手臂的拥有感的产生中起了重要的作用(Zeller, Gross, Bartsch, Johansen-Berg, & Classen, 2011).但是, 对此仍有不少问题.例如, 身体模型表征的人类身体是一般化的还是更为具体的, 即表征的是被试个人的身体参数?是否只有一个统一的身体模型还是身体的各个部分都有各自的模型?这些问题尤为重要.如果确实是身体模型在决定什么能够或不能够被体验为某人自己的一部分, 那么换言之, 只有与身体模型中“给定的”描述一致的对象才能被视为他们身体的一部分.如果身体模型描述了结构上的特征并且如果它在橡胶手错觉产生中起作用, 那么在拥有感中, 研究者就可以有如下的预期:(1)只有对象看起来和某人身体的一部分一样时才能被体验为其身体的部分(身体相似性限制); (2)只有完全相同一侧的身体对象才能被体验为身体的部分(同侧肢体限制); (3)一个人最多只能对两只手产生拥有感(双手限制) (Folegatti, Farnè, Salemme, & de Vignemont, 2012).迄今已有不少研究给出支持第一种预期的结果(Tsakiris, Carpenter, James, & Fotopoulou, 2010), 如果外部对象不具有身体部分的视觉相似性那么错觉将无法产生.但是, 在上文自下而上的认知机制中提起的将经典橡胶手错觉中的假手换成光秃秃的桌面, 同时用刷子刷被试被隐藏的真手和面前的桌面, 同样产生了橡胶手错觉(Armel & Ramachandran, 2003).最近的一项虚拟手错觉实验中, 使用猫爪同样使被试产生了拥有感(Chen et al., 2017).对于第二种预期, Tsakiris和Haggard的研究给出的是支持的结果.当把一只橡胶右手置于被试的左手附近并同时用刷子刷两只手时, 被试不会产生对橡胶手的拥有感(Tsakiris & Haggard, 2005).然而, Petkova和Ehrsson却给出了相反的证据.他们让被试把左手置于桌上可视的位置而把右手藏起来, 并在被试面前的桌上放上橡胶右手.实验过程中要求被试注视橡胶右手, 并同时用刷子轻刷被试真实的左手和橡胶右手.尽管两把刷子刷的并不是同一侧的手, 但被试仍报告能感受到来自橡胶手的触觉并表现出本体感觉的偏移.可见同侧肢体限制似乎并不是那么严格(Petkova & Ehrsson, 2009).对于第三个预测, 尽管Lane发现, 在产生对橡胶手的拥有感的时候, 被试对其真实的手产生了拥有感缺失(disownership), 至少左手在实验中有这种体验(Lane, Yeh, Tseng, & Chang, 2017).Della等人在生理学上也给出了同样的证据(Della Gatta et al., 2016), 以及Erro等人认为橡胶手错觉的产生并非是对真实手的拥有感缺失, 而是在视觉偏移作用下, 把橡胶手和真手整合成为一只手, 并且位于两只手之间的位置(Erro, Marotta, Tinazzi, Frera, & Fiorio, 2018).但Guterstam等人的研究给出了反例——多余手错觉(supernumerary hand illusion, SHI) (Guterstam, Petkova, & Ehrsson, 2011).在这一范式下, 被试能够同时看到自己的双手和橡胶手, 但是他们还是报告了来自橡胶手和来自自己真实手的触觉的感受, 最近的一项研究中被试也感觉自己不仅仅有两只手(Chen, Huang, Lee, & Liang, 2018).身体模型假说并不能给出令人信服的解释.

除了身体模型, 个人边缘空间(peri-personal space, PPS)也被认为对身体部分的自我归因有着重要的作用(Makin, Holmes, & Ehrsson, 2008).Makin等人发现看一个对象靠近假手时在后顶皮层(posterior parietal cortex)和右侧枕叶皮层(right lateral occipital cortex)产生的激活与看该对象靠近真手相同位置时产生的激活是相似的.但是如果没有手的呈现或假手位于无法够到的范围时, 这种激活是无法观察到的(Makin, Holmes, & Zohary, 2007).个人边缘空间是一种认知神经科学的概念, 它描述的是包围在人体周围的区域, 由整合多感官输入的特殊的大脑系统所表征.在拥有感错觉中, 源自假手的视觉信息与来自被隐藏的真手的本体感觉输入会被传输至解释手的位置的多感官脑区, 一旦橡胶手周围的空间被建立为手的边缘空间, “看到的”刷子在橡胶手上的碰触与“感到的”真手上的碰触就会被整合到一起被调整, 进而用于标志视觉-触觉事件在假手上的出现(Makin et al., 2008).关于被试真手和橡胶手之间的距离, 手周围的个人边缘空间非常重要.研究表明, 错觉的强度会随着橡胶手离解剖学上可能的手的位置的距离的增加呈现非线性的下降.Lloyd指出这可能反映了编码手边缘空间的双模态(视觉和触觉)神经元的激活.这可能涉及视觉接收区将外部对象纳入身体图式以及对被试被隐藏真手的触觉接收区的包围(Lloyd, 2007).

4 利用橡胶手错觉范式开展拥有感的病理学研究及临床实践

除了利用橡胶手错觉范式探索拥有感产生的认知与神经机制外, 运用橡胶手错觉范式来研究拥有感的病理学研究, 以及它们可能的在临床上的应用, 研究者同样寄予了很高的热情与期望.

4.1 拥有感的病理学研究

选择临床患者作为被试开展实验研究是橡胶手错觉病理学研究的尝试之一.Reinersmann等选用患有复杂性局部疼痛综合症(complex regional pain syndrome, CRPS)的患者作为实验组的被试来研究他们在橡胶手错觉中对与身体相关的刺激的高阶多感官整合能力方面的表现(Reinersmann et al., 2013).CRPS患者通过自我报告和皮肤电测试所显示的在错觉体验方面的表现与控制组的健康被试没有差异.这一结果表明尽管在本体感觉和触觉输入方面的加工是受损的, 但是这些患者高阶的多感官的整合功能却是没有受影响的.其次, 橡胶手错觉似乎是研究自闭症患者多感觉处理的有用工具, 自闭症患者更不容易对橡胶手产生拥有感, 能够很好地感知准确的本体位信息(Paton, Hohwy, & Enticott, 2012).自闭症儿童在橡胶手错觉实验中, 错觉产生的时间要比正常儿童平均晚6分钟, 而拥有感,自我与他人的关系是儿童自我意识,模仿以及共情发展的基础, 所以表现出更少同情的儿童往往不能感受到很强的错觉, 通过橡胶手错觉实验更好地了解自闭症中的身体表征, 可能对阐明社交赤字的神经基础并寻找未来的干预方法有重要意义(Cascio, Foss-Feig, Burnette, Heacock, & Cosby, 2012).研究还发现周期性的视触刺激会增强自闭症患者对橡胶手产生拥有感的强度, 因为自闭症这一特殊群体倾向于关注内感受(如心跳), 而周期性的刺激会潜在的和内感受建立联系, 进而增强橡胶手错觉产生中的视触刺激融合能力(Ide, & Wada, 2016).

此外, 精神分裂症患者也是橡胶手错觉病理学研究的主要对象之一, 已有研究表明精神分裂症患者(SZs)可能会比健康的控制组被试能够体验到更强烈的错觉体验(Mirucka, 2016; Peled, Ritsner, Hirschmann, Geva, & Modai, 2000).健康个体存在潜在抑制, 产生橡胶手错觉的时间比精神分裂症患者要长, 但是健康个体能很容易学会这种错觉产生的过程, 而SZs个体因为有认知障碍不能像正常个体一样学会橡胶手错觉产生的过程(Lev-Ari, Hirschmann, Dyskin, Goldman, & Hirschmann, 2015).Germine等对55名健康的成年人进行橡胶手错觉实验, 通过对被试自我报告的精神病样特征(psychosis-like characteristics)与对橡胶手的身体拥有感的易感性进行分析得出结论, 对由感官信息导致的身体表征曲解的易感性可能与精神病或阳性的精神病样特征有关(Germine, Benson, Cohen, & Hooker, 2013).更直接的证据来自Asai等人对分裂型人格特征与橡胶手错觉实验中的表现之间的关系进行的研究.他们检验了橡胶手错觉中的个体差异, 包括移情与分裂型的特质, 正如之前的研究所认为的精神分裂症患者会更容易产生橡胶手错觉.此外他们的研究结果还表明体验到更强烈的橡胶手错觉的被试可能同时会拥有更强烈的移情与分裂型的人格特征(Asai, Mao, Sugimori, & Tanno, 2011).橡胶手错觉范式的研究应该能为更好了解精神分裂症等疾病的病因与临床表现提供更多有价值的数据.

4.2 临床应用设想

在临床应用上, 橡胶手错觉与拥有感的研究同样也可以被用于探究截肢病人术后对假肢的拥有感.如那些被用于疼痛的感觉运动刺激手术中的皮层电刺激可能也能为进一步理解对错觉的皮层表征提供一个机会, 从而可能为个体的身体拥有感的调节提供机会.因此, 橡胶手错觉还可能成为神经康复干预中的一个重要的工具.研究者开始发掘橡胶手错觉在研究截肢病人被改变的身体映射的功能方面的潜力, 从而使得身体意象干预成为一种有效的康复工具(Ramakonar, Franz, & Lind, 2011).例如, 有研究者提出这样一种设想, 是否可以将假肢设计成有触觉感官的, 并且使之与躯体的触觉刺激相联系, 即人为地在假肢和被试真实身体之间进行类似于橡胶手错觉实验的过程(Edin et al., 2008).当假肢碰到某个对象时, 被试身体的对应部位也会产生触觉体验, 这反过来就能够传播一种多感官的信号进而“欺骗”大脑使之相信触觉感觉是来自于人造四肢的, 并且是属于当事人的.对肢体的这种拥有感就能够使得假肢更容易也更直接的使用.而且, 这种技术也能够降低身体对于人造肢体的不满意度(Ehrsson et al., 2008).近期Scandola等人发现对于四肢瘫痪者, 在同步刷脸部和橡胶手时, 能够产生对橡胶手的拥有感, 这种手脸交换的现象或许对脊髓损伤重建自我感有重要作用(Scandola et al., 2014).Burin等人固定健康被试的四肢一段时间, 使用橡胶手错觉范式发现在行为指标和问卷测试两个方面均发现固定肢体的被试产生的拥有感错觉要比不固定四肢的被试强(Burin et al., 2017), 以上结果对于神经外科和术后康复都有着重要的意义.

使用弥散加权成像(diffusion-weighted imaging, DWI)技术, 橡胶手错觉范式, 对脑损伤的患者进行实验, 发现未产生橡胶手错觉(RHIF)的病人, 腹侧前运动皮层(PMv)或者附属结构损伤, 没有产生RHIF的躯体失认症(body agnosia)患者中, PMv及其附属结构没有损伤.躯体失认症的治疗至少可以从PMv结构功能的完整性入手, 为临床治疗指明方向(Zeller et al., 2011).最近有研究者使用橡胶手错觉研究强迫症患者的厌恶感, 实验首先让被试产生橡胶手错觉, 进而在橡胶手上放置恶心刺激, 如血液,粪便或呕吐物, 同步刷看不见的真手和橡胶手比不同步条件下产生更强的类似强迫症的厌恶感, 为治疗强迫症障碍提供了活体暴露干预的可能(Jalal, Krishnakumar, & Ramachandran, 2015).另外, Siedlecka发现, 产生橡胶手错觉情况下, 被试从电刺激中感受到更加疼痛的体验, 对刺激的感知部位也向橡胶手方位偏移(Siedlecka, Spychała, Łukowska,Wiercioch, & Wierzchoń, 2018).行为和主观测量都发现, 橡胶手错觉能减轻对冷的不舒服感, 产生的错觉强度越强, 冷的不舒适感产生的越晚, 强度越小.对热,拥有感以及橡胶手错觉下对痛觉的理论和方法论研究提供了可能(Siedlecka, Klimza, Łukowska, & Wierzchon, 2014).

5 展望

总之, 橡胶手错觉作为一个新兴的研究范式, 对拥有感的研究产生了很多有意义的影响.因为这一范式有助于进一步了解研究者自身的信息整合加工过程, 对拥有感产生过程中多感觉整合的模式, 即自上而下和自下而上加工机制进行更深入的探究.此外为了使拥有感研究能够更好地应用于临床的各个方面, 橡胶手错觉范式是一个很好的研究对象与工具.并且值得庆幸的是, 橡胶手错觉与拥有感的研究正在吸引越来越多研究者的关注.其未来可以在如下几个方面继续拓展与深化.

首先, 拓展与丰富橡胶手错觉范式及其变式.随着橡胶手错觉实验研究范围的扩大以及引入新的刺激材料的需要, 一种新的与橡胶手错觉范式有着异曲同工之妙的实验范式悄然兴起.大量的研究证实通过虚拟现实, 即用电脑中的虚拟手代替橡胶手, 同样能够实现橡胶手错觉.虚拟手错觉(virtual hand illusion, VHI)中最常用的方法就是将一只虚拟的三维手的图像呈现在被试面前的电脑屏幕上, 同时要求被试边移动自己被隐藏的手边观察屏幕上虚拟手的运动.研究表明, VHI范式能够很好地实现传统RHI范式下的效果, 即对被试真实的,被隐藏的手施加触觉刺激, 同时对屏幕中的虚拟手也施加同步的相同刺激, 被试会在实验结束后报告与RHI实验中相似的体验(Ma & Hommel, 2013).如图3所示.

图3

图3   虚拟手错觉实验设备与示范


甚至有研究表明, 即便没有真实的刺激, 仅仅通过操纵被试真实手的运动与屏幕中虚拟手的运动之间的时间差同样能产生相同的错觉效果(Sanchez-Vives, Spanlang, Frisoli, Bergamasco, & Slater, 2010).此外, 较之橡胶手错觉范式, 无论是从实验设计的严谨性还是从操作过程的便捷性亦或是从刺激材料的广泛性方面, 虚拟手错觉范式都具有前者无可比拟的优势.首先, 从实验设计来讲, RHI实验过程中所选用的道具可变性不如VHI实验中的大.即VHI实验中, 可以根据被试的实际情况选取与被试的真实手尽可能接近的虚拟手的图案, 而RHI实验无法提供如此多样的仿真手.因此, VHI所能提供的更好的仿真效果将能够更加有利于实验的开展.其次, 从操作过程而言, RHI实验过程所要求的同步刺激只能通过人为的方式实现, 且每次实验过程中同步性的程度难免不一, 但VHI通过电脑控制作用于真实手和虚拟手的刺激不仅可以保证不同被试在各自实验过程中刺激的同步性, 而且还能对刺激是否同步对错觉产生效果的影响进行更精确的深入研究.第三, 从刺激材料来讲, VHI中所能选用的刺激材料也较之RHI更为丰富, 它使得探索新奇的刺激成为可能.VHI在刺激材料方面的开放程度也使得研究者能够在更大的范围内对自主感与拥有感等进行更深入的研究成为可能.

其次, 通过橡胶手错觉中被试拥有感的表现来寻找其与心理特质或人格特征之间的关系也是未来研究值得进一步关注的方向之一.Marotta等人发现, 通过感觉暗示性量表(Sensory Suggestibility Scale,SSS)筛选出的高感受暗示性(High-SSS)的个体在拥有感评分的主观报告上对橡胶手产生更高的拥有感, 而对本体感觉偏移得客观测量上并没有发现高感受暗示性和低感受暗示性(Low-SSS)个体间的显著差异.为今后使用橡胶手错觉范式时, 被试以及测量指标的选择提供了新的思考(Marotta, Tinazzi, Cavedini, Zampini, & Fiorio, 2016).关于个体对橡胶手错觉的易感性, Costantini等(2016)通过实证研究发现, 易感性程度和个体对视触等多感觉融合感知的时间分辨率有很大关系, 因此后续对橡胶手错觉的神经认知研究中可以引入时间这一维度.此外, 还有研究者发现影响橡胶手错觉产生的本体位偏移,拥有感和拥有感缺失均和个体气质因素有关(Kállai et al., 2015).因此, 心理特质或者人格特征也是使用橡胶手错觉应该考虑的问题.目前对于橡胶手错觉实验一般通过主观的自我报告和客观的本体位偏移,皮肤电测量来评估, 未来研究可以从内隐和外显多角度测量错觉产生的强度.

再次, 借助橡胶手错觉范式, 围绕拥有感对具身认知研究中的相关论题进行系统探索.拥有感的研究对于意识体验的具身性有着重要的意义, 橡胶手错觉范式在该领域的应用将能为意识体验的具身性提供更加详实的实证支持.来自具身认知的研究证据指出, 意识活动并非只局限于大脑, 而且还包含了嵌入在环境之中的身体, van der Hoort等就通过橡胶手错觉范式论证了上述观点.实验中, 被试平躺在床上, 同时戴上一副头盔式显示器(head-mounted displays, HMDs), 并将其连接在一套由三脚架架设的照相机上.通过该设备以及这种特殊的处理, 被试无法看到自己真实的身体, 但是可以通过显示器看到实验者想让他们看到的比自己身体大很多的巨人娃娃和比自己身体小很多的迷你娃娃.实验采用与经典橡胶手错觉范式类似的方法, 同时轻触被试真实的身体和被试所能看到的放大或缩小的身体.在此过程中, 被试不仅能够将放大的或缩小的身体体验为自己的身体, 而且当体验放大的身体时, 他们会感觉周围的事物都变小了, 反之当体验缩小的身体是, 他们会觉得周围的一切都变大了(van der Hoort et al., 2011).

此外, 如前所述与拥有感有着密切关系的自主感, 目前还很少有研究使用橡胶手错觉范式对其进行考察.近期一项研究使用虚拟现实技术, 应用虚拟手错觉范式, 发现相比拥有感, 自主感能够更好的预测个体的焦虑水平, 男性在自主感上表现更强, 可能是由于性别归因风格与移情能力的不同, 自主感和拥有感在不同情绪事件中相互影响, 压力情景下的危险情况受到的影响要比奖赏条件下更强(Chen, Zhang, Qian, & Gao, 2017).今后的研究应尽可能地在谨慎区别两者的基础上进一步深入探究其认知与神经机制.例如, 是否可以在橡胶手错觉范式中改变一些条件, 从而创造出分离自主感与拥有感的实验设计(有自主感而无拥有感,有拥有感而无自主感,既有自主感又有拥有感以及既无自主感又无拥有感), 进而对身体自我觉知,意识体验的具身感等话题进行更加深入的研究.

最后, 将橡胶手错觉范式在临床应用上的价值从机制解释转化为康复治疗.前橡胶手错觉范式的应用总体来说还是局限于实验室探究, 接下来的目标应该是让橡胶手错觉能够产生更加直接的临床价值(Christ & Reiner, 2014).已有研究使用虚拟现实手段治疗抑郁症患者, 患者佩戴头戴式显示器进入使用3DsMAX软件创建的虚拟环境, 要求患者按照情景设定练习向虚拟人表达移情, 然后从另一个虚拟人角度体验接收同情.结果发现三次情景模拟就能显著降低抑郁严重性, 4周的追踪观察后, 其中4个被试的临床症状明显减轻(Falconer et al., 2016).虚拟身体错觉实验模型产生的虚拟身体拥有感体验能够降低社交焦虑, 这一错觉影响身体感知和社会认知, 为治疗社交焦虑障碍提供新的治疗方法(Guterstam et al., 2015).已有研究表明使用橡胶手错觉范式开展了有关身体拥有感(Jenkinson, Haggard, Ferreira, & Fotopoulou, 2013; Ocklenburg, Peterburs, Rücklenburg, türkün, 2012),身体表征(body representation) (Davies, White & Davies, 2013; Davies & White, 2013),身体意象(body image) (Davies & White, 2013; Davies, White, & Davies, 2013)的研究, 而身体拥有感,身体表征与身体意象又与诸如神经性厌食症等疾病有着密切联系的方面.目前, 已有研究证实女性厌食症患者比正常女性更容易产生橡胶手错觉(Keizer, Smeets, Postma, van Elburg, &Dijkerman, 2014).此外, 也有研究发现, 述情障碍得分高的个体对多重感觉的整合能力较得分低的强, 容易产生橡胶手错觉, 对错觉易感程度高, 述情障碍得分高的个体和异常关注自己身体有关(Grynberg & Pollatos, 2015).综合上述两个方面的证据, 可以考虑将橡胶手错觉中对于橡胶手的拥有感的易感性作为罹患神经性厌食症等饮食障碍的一项指标, 从而为更好地筛查出易感人群进行提前干预提供更精确的指标.如图4所示.

图4

图4   橡胶手错觉范式对神经性厌食症的预测


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When participants observed a rubber hand being touched, their sense of touch was activated (rubber hand illusion: RHI). While this illusion might be caused by multi-modal integration, it may also be related to empathic function, which enables us to simulate the observed information. We examined individual differences in the RHI, including empathic and schizotypal personality traits, as previous research had suggested that schizophrenic patients would be more subject to the RHI. The results indicated that people who experience a stronger RHI might have stronger empathic and schizotypal personalites simultaneously. We discussed these relationships in terms of self-other representations.

Balconi M., & Bortolotti A. (2010).

Body and self-awareness: Functional and dysfunctional mechanisms.

In M. Balconi (Ed.),Neuropsychology of the Sense of Agency(pp. 173-189). Milano: Springer.

URL     [本文引用: 2]

Some features of human experience contribute to a person’s self-consciousness as the “ability to represent one’s own bodily and mental states as one’s own states” [ 1 ]. Although some aspects of this ability are phenomenologically the same, they are heterogeneous on both the functional and the representational level. Experienced phenomena involved in self-consciousness are the sum of one’s own experiences, the perspectivity of these experiences, the sense of ownership of one’s own body parts, the sense of agency of actions, the sense of authorship of thoughts, and the trans-temporal integration of all this into autobiographical knowledge [ 1 ]. These aspects highlight the psychological, physiological, and neural mechanisms involved in bodily experience and important for self-consciousness.

Bekrater-Bodmann R., Foell J., Diers M., & Flor H . (2012).

The perceptual and neuronal stability of the rubber hand illusion across contexts and over time.

Brain Research, 1452, 130-139.

URL     PMID:22459041      [本文引用: 1]

78 Contextual and temporal stabilities of illusory embodiment were assessed. 78 The individual degree of susceptibility prevails in different contexts. 78 There is intra-individual stability over time with no changes in illusory experience. 78 Neuronal processes underlying these sensations seem to be trait-like. 78 These results indicate an intra-individually stable trait for sensory integration.

Botvinick M. . (2004).

Probing the neural basis of body ownership.

Science, 305 (5685), 782-783.

[本文引用: 1]

Botvinick M., & Cohen J. (1998).

Rubber hands ‘feel’touch that eyes see.

Nature, 391(6669), 756.

[本文引用: 4]

Braun N., Debener S., Spychala N., Bongartz E., Sörös P., Müller H. H. O., & Philipsen A . (2018).

The senses of agency and ownership: A review.

Frontiers in Psychology, 9, 535.

URL     [本文引用: 1]

Usually, we do not question that we possess a body and act upon the world. This pre-reflective awareness of being a bodily and agentive self can, however, be disrupted by different clinical conditions. Whereas sense of ownership (SoO) describes the feeling of mineness toward one own body parts, feelings or thoughts, sense of agency (SoA) refers to the experience of initiating and controlling an action. Although SoA and SoO naturally coincide, both experiences can also be made in isolation. By using many different experimental paradigms, both experiences have been extensively studied over the last years. This review introduces both concepts, with a special focus also onto their interplay. First, current experimental paradigms, results and neurocognitive theories about both concepts will be presented and then their clinical and therapeutic relevance is discussed.

Burin D., Garbarini F., Bruno V., Fossataro C., Destefanis C., Berti A., & Pia L . (2017).

Movements and body ownership: Evidence from the rubber hand illusion after mechanical limb immobilization.

Neuropsychologia, 107, 41-47.

URL     PMID:29109038      [本文引用: 1]

Abstract There is no consensus on whether, and to what extent, actions contribute to constructing awareness of one's own body. Here we investigated at both physiological and behavioral level whether a prolonged limb immobilization affects body ownership. We tested a group of healthy participants, whose left-hand movements were prevented by a cast for one week, and a control group without any movement restriction. In both groups, we measured the strength of the rubber hand illusion (i.e., proprioceptive shift and questionnaire on ownership) and the physiological parameters known to be modulated by short-term arm immobilization (i.e., resting motor threshold, motor evoked potentials and force parameters) before and after the week of immobilization. Our results showed stronger illusory effects on the immobilized hand on both behavioral indexes and weaker illusory effects on the non-immobilized hand on the questionnaire. Additionally, the increased proprioceptive shift was positively correlated to the motor threshold of the contralateral hemisphere. Our findings show at both behavioral and physiological level that altering those movement-related signals which constantly stem from our own body parts, modulates the experience of those body parts as mine. This, in turn, supports the view of a direct role of actions in the developing and maintaining a coherent body ownership. Copyright 2017 Elsevier Ltd. All rights reserved.

Burin D., Livelli A., Garbarini F., Fossataro C., Folegatti A., Gindri P., & Pia L . (2015).

Are movements necessary for the sense of body ownership? Evidence from the rubber hand illusion in pure hemiplegic patients.

PLoS One, 10(3), e0117155.

URL     PMID:4361688     

Abstract A question still debated within cognitive neuroscience is whether signals present during actions significantly contribute to the emergence of human's body ownership. In the present study, we aimed at answer this question by means of a neuropsychological approach. We administered the classical rubber hand illusion paradigm to a group of healthy participants and to a group of neurological patients affected by a complete left upper limb hemiplegia, but without any propriceptive/tactile deficits. The illusion strength was measured both subjectively (i.e., by a self-report questionnaire) and behaviorally (i.e., the location of one's own hand is shifted towards the rubber hand). We aimed at examining whether, and to which extent, an enduring absence of movements related signals affects body ownership. Our results showed that patients displayed, respect to healthy participants, stronger illusory effects when the left (affected) hand was stimulated and no effects when the right (unaffected) hand was stimulated. In other words, hemiplegics had a weaker/more flexible sense of body ownership for the affected hand, but an enhanced/more rigid one for the healthy hand. Possible interpretations of such asymmetrical distribution of body ownership, as well as limits of our results, are discussed. Broadly speaking, our findings suggest that the alteration of the normal flow of signals present during movements impacts on human's body ownership. This in turn, means that movements have a role per se in developing and maintaining a coherent body ownership.

Campos J. L., Richandi G. E. K., Taati B., & Keshavarz B . (2018).

The rubber hand illusion in healthy younger and older adults.

Multisensory Research, 31(6), 537-555.

[本文引用: 1]

Carruthers G. . (2013).

Toward a cognitive model of the sense of embodiment in a (rubber) hand.

Journal of Consciousness Studies, 20(3-4), 33-60.

URL     Magsci     [本文引用: 1]

The rubber hand illusion (RHI) is the experience of an artificial body part as being a real body part and the experience of touch coming from that artificial body part. An explanation of this illusion would take significant steps towards explaining the experience of embodiment. I present a new cognitive model to explain the RHI. I argue that the sense of embodiment arises when an online representation of the candidate body part is represented as matching an offline prototype representation of what one's body is usually like. The cause of the sense of embodiment in the model body part only partially overlaps with the causes of proprioceptive drift, which commonly accompanies the RHI, and so is compatible with observed dissociations between the illusion and proprioceptive drift. The distinguishing features of this model are the offline body representation, and the process of matching an online model to an offline model, both of which are to be understood in terms of a conceptual space.

Carruthers G. . (2015).

Who am I in out of body experiences? Implications from OBEs for the explanandum of a theory of self-consciousness.

Phenomenology and the Cognitive Sciences, 14(1), 183-197.

URL     [本文引用: 1]

Contemporary theories of self-consciousness typically begin by dividing experiences of the self into types, each requiring separate explanation. The stereotypical case of an out of body experience (OBE) may be seen to suggest a distinction between the sense of oneself as an experiencing subject, a mental entity, and a sense of oneself as an embodied person, a bodily entity. Point of view, in the sense of the place from which the subject seems to experience the world, in this case is tied to the sense of oneself as a mental entity and seems to be the 'real' self. Closer reading of reports, however, suggests a substantially more complicated picture. For example, the 'real' self that is experienced as separate from the body in an OBE is not necessarily experienced as disembodied. Subjects may experience themselves as having two bodies. In cases classed as heautoscopy there is considerable confusion regarding the apparent location of the experiencing subject; is it the 'real mind' in the body I seem to be looking out from, or is it in the body that I see? This suggests that visual point of view can dissociate from the experience of one's own "real mind" or experience of self-identification. I provide a tripartite distinction between the sense of ownership, the sense of embodiment and the sense of subjectivity to better describe these experiences. The phenomenology of OBEs suggests that there are three distinct forms of self-consciousness which need to be explained.

Cascio C. J., Foss-Feig J. H., Burnette C. P., Heacock J. L., & Cosby A. A . (2012).

The rubber hand illusion in children with autism spectrum disorders: Delayed influence of combined tactile and visual input on proprioception.

Autism, 16(4), 406-419.

URL     PMID:22399451      Magsci     [本文引用: 1]

ABSTRACT In the rubber hand illusion, perceived hand ownership can be transferred to a rubber hand after synchronous visual and tactile stimulation. Perceived body ownership and self-other relation are foundational for development of self-awareness, imitation, and empathy, which are all affected in autism spectrum disorders (ASD). We examined the rubber hand illusion in children with and without ASD. Children with ASD were initially less susceptible to the illusion than the comparison group, yet showed the effects of the illusion after 6 minutes. Delayed susceptibility to the illusion may result from atypical multisensory temporal integration and/or an unusually strong reliance on proprioception. Children with ASD who displayed less empathy were significantly less likely to experience the illusion than those with more intact ability to express empathy. A better understanding of body representation in ASD may elucidate neural underpinnings of social deficits, thus informing future intervention approaches.

Chen W. Y., Huang H. C., Lee Y. T., & Liang C . (2018).

Body ownership and the four-hand illusion.

Scientific Reports, 8(1), 2153.

URL     PMID:29391505      [本文引用: 2]

Recent studies of the rubber hand illusion (RHI) have shown that the sense of body ownership is constrained by several factors and yet is still very flexible. However, exactly how flexible is our sense of body ownership? In this study, we address this issue by investigating the following question: is it possible that one may have the illusory experience of owning four hands? Under visual manipulation, the participant adopted the experimenter’s first-person perspective (1PP) as if it was his/her own. Sitting face to face, the participant saw four hands—the experimenter’s two hands from the adopted 1PP together with the subject’s own two hands from the adopted third-person perspective (3PP). We found that: (1) the four-hand illusion did not occur in the passive four-hand condition. (2) In the active four-hand condition, the participants tapped their index fingers, imitated by the experimenter. When tactile stimulations were not provided, the key illusion was not induced, either. (3) Strikingly, once all four hands began to act with the same pattern and received synchronous tactile stimulations at the same time, many participants felt as if they had two more hands. These results show that the sense of body ownership is much more flexible than most researchers have suggested.

Chen W., Zhang J., Qian Y. Y., & Gao Q. Y . (2017).

How disentangled sense of agency and sense of ownership can interact with different emotional events on stress feelings.

Psicologia: Reflexão e Crítica, 30, 17.

URL     [本文引用: 2]

We used the virtual hand illusion paradigm to study how sense of agency and sense of (body) ownership can interact with different emotional events on stress feelings. Converging evidence for at least

Christ O., & Reiner M. (2014).

Perspectives and possible applications of the rubber hand and virtual hand illusion in non-invasive rehabilitation: Technological improvements and their consequences.

Neuroscience & Biobehavioral Reviews, 44(7), 33-44.

URL     PMID:24661983      [本文引用: 2]

This review introduces theoretical aspects of the rubber hand illusion (RHI) and virtual hand illusion (VHI), and discusses their possible clinical applications. It also presents technical improvements regarding the realization of the RHI and VHI and their relation to rehabilitation issues. There is presently little evidence describing the value of the RHI and VHI as indices in the diagnosis or treatment of different pathologies, likely because of a lack of standardization in reporting the results of RHI and VHI studies. In contrast, a new emerging “out-of-body illusion” appears to be an interesting new approach; however, as in RHI and VHI, there are additional consequences regarding its application in clinical settings because of its technological demands. This review considers the acceptance of technology and the realization of immersion/presence in the context of virtual rehabilitation.

Costantini M., Robinson J., Migliorati D., Donno B., Ferri F., & Northoff G . (2016).

Temporal limits on rubber hand illusion reflect individuals’ temporal resolution in multisensory perception.

Cognition, 157, 39-48.

URL     PMID:27592410     

Synchronous, but not asynchronous, multisensory stimulation has been successfully employed to manipulate the experience of body ownership, as in the case of the rubber hand illusion. Hence, it has been assumed that the rubber hand illusion is bound by the same temporal rules as in multisensory integration. However, empirical evidence of a direct link between the temporal limits on the rubber hand illusion and those on multisensory integration is still lacking. Here we provide the first comprehensive evidence that individual susceptibility to the rubber hand illusion depends upon the individual temporal resolution in multisensory perception, as indexed by the temporal binding window. In particular, in two studies we showed that the degree of temporal asynchrony necessary to prevent the induction of the rubber hand illusion depends upon the individuals sensitivity to perceiving asynchrony during visuo-tactile stimulation. That is, the larger the temporal binding window, as inferred from a simultaneity judgment task, the higher the level of asynchrony tolerated in the rubber hand illusion. Our results suggest that current neurocognitive models of body ownership can be enriched with a temporal dimension.Moreover, our results suggest that the different aspects of body ownership operate over different time scales.

Davies A. M.A., &White R.C . (2013).

A sensational illusion: Vision-touch synaesthesia and the rubber hand paradigm.

Cortex, 49(3), 806-818.

URL     PMID:22445446      Magsci     [本文引用: 2]

For individuals with vision-touch synaesthesia, the sight of touch on another person elicits synaesthetic tactile sensation on the observer’s own body. Here we used the traditional rubber hand paradigm (Botvinick and Cohen, 1998) and a no-touch rubber hand paradigm to investigate and to authenticate synaesthetic tactile sensation. In the traditional rubber hand paradigm, the participant views a prosthetic hand being touched by the Examiner while the participant’s hand – hidden from view – is also touched by the Examiner. Synchronous stimulation of the prosthetic hand and the participant’s hidden hand elicits the rubber hand illusion. It may seem to the participant that she is feeling touch at the location of the viewed prosthetic hand – visual capture of touch, and that the prosthetic hand is the participant’s own hand – illusion of ownership. Thus, for participants who experience the traditional rubber hand illusion, tactile sensation on the participant’s hidden hand is referred to the prosthetic hand. In our no-touch rubber hand paradigm, the participant views a prosthetic hand being touched by the Examiner but the participant’s hand – hidden from view – is not touched by the Examiner. Questionnaire ratings indicated that only individuals with vision-touch synaesthesia experienced the no-touch rubber hand illusion. Thus, synaesthetic tactile sensation on the (untouched) hidden hand was referred to the prosthetic hand. These individuals also demonstrated proprioceptive drift (a change, from baseline, in proprioceptively perceived position) of the hidden hand towards the location of the prosthetic hand, and a pattern of increased proprioceptive drift with increased trial duration (60sec, 180sec, 300sec). The no-touch rubber hand paradigm was an excellent method to authenticate vision-touch synaesthesia because participants were na07ve about the rubber hand illusion, and they could not have known how they were expected to perform on either the traditional or the no-touch rubber hand paradigm.

Davies A. M. A., White R. C., & Davies M . (2013).

Spatial limits on the nonvisual self-touch illusion and the visual rubber hand illusion: Subjective experience of the illusion and proprioceptive drift.

Consciousness and Cognition, 22(2), 613-636.

URL     PMID:23644413      Magsci     [本文引用: 5]

The nonvisual self-touch rubber hand paradigm elicits the compelling illusion that one is touching one’s own hand even though the two hands are not in contact. In four experiments, we investigated spatial limits of distance (15cm, 30cm, 45cm, 60cm) and alignment (0°, 90° anti-clockwise) on the nonvisual self-touch illusion and the well-known visual rubber hand illusion. Common procedures (synchronous and asynchronous stimulation administered for 60s with the prosthetic hand at body midline) and common assessment methods were used. Subjective experience of the illusion was assessed by agreement ratings for statements on a questionnaire and time of illusion onset. The nonvisual self-touch illusion was diminished though never abolished by distance and alignment manipulations, whereas the visual rubber hand illusion was more robust against these manipulations. We assessed proprioceptive drift, and implications of a double dissociation between subjective experience of the illusion and proprioceptive drift are discussed.

de Vignemont F. (2011).

Embodiment, ownership and disownership.

Consciousness and Cognition, 20(1), 82-93.

Magsci     [本文引用: 1]

There are two main pathways to investigate the sense of body ownership, (i) through the study of the conditions of embodiment for an object to be experienced as one's own and (ii) through the analysis of the deficits in patients who experience a body part as alien. Here. I propose that E is embodied if some properties of E are processed in the same way as the properties of one's body. However, one must distinguish among different types of embodiment, and only self-specific embodiment can lead to feelings of ownership. I address issues such as the functional role and the dynamics of embodiment, degrees and measures of ownership, and shared body representations between self and others. I then analyse the interaction between ownership and disownership. On the one hand. I show that there is no evidence that in the Rubber Hand Illusion, the rubber hand replaces the biological hand. On the other hand, I argue that the sense of disownership experienced by patients towards their body part cannot be reduced to the mere lack of ownership. (C) 2010 Elsevier Inc. All rights reserved.

Della Gatta F., Garbarini F., Puglisi G., Leonetti A., Berti A., & Borroni P . (2016).

Decreased motor cortex excitability mirrors own hand disembodiment during the rubber hand illusion.

Elife, 5, e14972.

URL     PMID:27760692      [本文引用: 1]

10.7554/eLife.14972.001During the rubber hand illusion (RHI), subjects experience an artificial hand as part of their own body, while the real hand is subject to a sort of 'disembodiment'. Can this altered belief about the body also affect physiological mechanisms involved in body-ownership, such as motor control? Here we ask whether the excitability of the motor pathways to the real (disembodied) hand are affected by the illusion. Our results show that the amplitude of the motor-evoked potentials recorded from the real hand is significantly reduced, with respect to baseline, when subjects in the synchronous (but not in the asynchronous) condition experience the fake hand as their own. This finding contributes to the theoretical understanding of the relationship between body-ownership and motor system, and provides the first physiological evidence that a significant drop in motor excitability in M1 hand circuits accompanies the disembodiment of the real hand during the RHI experience.DOI: http://dx.doi.org/10.7554/eLife.14972.001

Edin B. B., Ascari L., Beccai L., Roccella S., Cabibihan J. -J., & Carrozza M . (2008).

Bio-inspired sensorization of a biomechatronic robot hand for the grasp-and-lift task.

Brain Research Bulletin, 75(6), 785-795.

URL     PMID:18394525      [本文引用: 2]

It has been concluded from numerous neurophysiological studies that humans rely on detecting discrete mechanical events that occur when grasping, lifting and replacing an object, i.e., during a prototypical manipulation task. Such events represent transitions between phases of the evolving manipulation task such as object contact, lift-off, etc., and appear to provide critical information required for the sequential control of the task as well as for corrections and parameterization of the task. We have sensorized a biomechatronic anthropomorphic hand with the goal to detect such mechanical transients. The developed sensors were designed to specifically provide the information about task-relevant discrete events rather than to mimic their biological counterparts. To accomplish this we have developed (1) a contact sensor that can be applied to the surface of the robotic fingers and that show a sensitivity to indentation and a spatial resolution comparable to that of the human glabrous skin, and (2) a sensitive low-noise three-axial force sensor that was embedded in the robotic fingertips and showed a frequency response covering the range observed in biological tactile sensors. We describe the design and fabrication of these sensors, their sensory properties and show representative recordings from the sensors during grasp-and-lift tasks. We show how the combined use of the two sensors is able to provide information about crucial mechanical events during such tasks. We discuss the importance of the sensorized hand as a test bed for low-level grasp controllers and for the development of functional sensory feedback from prosthetic devices.

Ehrsson H. H., Rosén B., Stockselius A., Ragnö C., Köhler P., & Lundborg G . (2008).

Upper limb amputees can be induced to experience a rubber hand as their own.

Brain, 131(12), 3443-3452.

URL     PMID:2639202     

We describe how upper limb amputees can be made to experience a rubber hand as part of their own body. This was accomplished by applying synchronous touches to the stump, which was out of view, and to the index finger of a rubber hand, placed in full view (26 cm medial to the stump). This elicited an illusion of sensing touch on the artificial hand, rather than on the stump and a feeling of ownership of the rubber hand developed. This effect was supported by quantitative subjective reports in the form of questionnaires, behavioural data in the form of misreaching in a pointing task when asked to localize the position of the touch, and physiological evidence obtained by skin conductance responses when threatening the hand prosthesis. Our findings outline a simple method for transferring tactile sensations from the stump to a prosthetic limb by tricking the brain, thereby making an important contribution to the field of neuroprosthetics where a major goal is to develop artificial limbs that feel like a real parts of the body.

Ehrsson H. H., Spence C., & Passingham R. E . (2004).

That's my hand! Activity in premotor cortex reflects feeling of ownership of a limb.

Science, 305(5685), 875-877.

[本文引用: 1]

Erro R., Marotta A., Tinazzi M., Frera E., & Fiorio M . (2018).

Judging the position of the artificial hand induces a "visual" drift towards the real one during the rubber hand illusion.

Scientific Reports, 8(1), 2531.

URL     [本文引用: 1]

When subjects look at a rubber hand being brush-stroked synchronously with their own hidden hand, they might feel a sense of ownership over the rubber hand. The perceived mislocalization of the own hand towards the rubber hand (proprioceptive drift) would reflect an implicit marker of this illusion occurring through the dominance of vision over proprioception. This account, however, contrasts with principles of multisensory integration whereby percepts result from a tatistical sum of different sensory afferents. In this case, the most-known proprioceptive drift should be mirrored by complementaryvisualdrift of the rubber hand in the opposite direction. We investigated this issue by designing two experiments in which subjects were not only requested to localize their own hand but also the rubber hand and further explored the subjective feeling of the illusion. In both experiments, we demonstrated a (visual) drift in the opposite direction of the proprioceptive drift, suggesting that both hands converge toward each other. This might suggest that the spatial representations of the two hands are integrated in a common percept placed in between them, contradicting previous accounts of substitution of the real hand by the rubber hand.

Falconer C. J., Rovira A., King J. A., Gilbert P., Antley A., Fearon P., .. Brewin C. R . (2016).

Embodying self- compassion within virtual reality and its effects on patients with depression.

British Journal of Psychiatry Open, 2(1), 74-80.

URL     PMID:4995586     

Self-criticism is a ubiquitous feature of psychopathology and can be combatted by increasing levels of self-compassion. However, some patients are resistant to self-compassion. To investigate whether the effects of self-identification with virtual bodies within immersive virtual reality could be exploited to increase self-compassion in patients with depression. We developed an 8-minute scenario in which 15 patients practised delivering compassion in one virtual body and then experienced receiving it from themselves in another virtual body. In an open trial, three repetitions of this scenario led to significant reductions in depression severity and self-criticism, as well as to a significant increase in self-compassion, from baseline to 4-week follow-up. Four patients showed clinically significant improvement. The results indicate that interventions using immersive virtual reality may have considerable clinical potential and that further development of these methods preparatory to a controlled trial is now warranted. None. The Royal College of Psychiatrists 2016. This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY) licence.

Flögel M., Kalveram K. T., Christ O., & Vogt J . (2016).

Application of the rubber hand illusion paradigm: Comparison between upper and lower limbs.

Psychological Research, 80(2), 298-306.

URL     PMID:25656162      [本文引用: 1]

http://link.springer.com/10.1007/s00426-015-0650-4

Folegatti A., Farnè A., Salemme R., & de Vignemont F . (2012).

The rubber hand illusion: Two’s a company, but three’s a crowd.

Consciousness and Cognition, 21(2), 799-812.

Magsci     [本文引用: 1]

On the one hand, it is often assumed that the Rubber Hand Illusion (RHI) is constrained by a structural body model so that one cannot implement supernumerary limbs. On the other hand, several recent studies reported illusory duplication of the right hand in subjects exposed to two adjacent rubber hands. The present study tested whether spatial constraints may affect the possibility of inducing the sense of ownership to two rubber hands located side by side to the left of the subject's hand. We found that only the closest rubber hand appeared both objectively (proprioceptive drift) and subjectively (ownership rating) embodied. Crucially, synchronous touch of a second, but farther, rubber hand disrupted the objective measure of the RHI, but not the subjective one. We concluded that, in order to elicit a genuine RHI for multiple rubber hands, the two rubber hands must be at the same distance from the subject's hand/body. (C) 2012 Elsevier Inc. All rights reserved.

Gallagher S. . (2000).

Philosophical conceptions of the self: Implications for cognitive science.

Trends in Cognitive Sciences, 4(1), 14-21.

[本文引用: 1]

Germine L., Benson T. L., Cohen F ., & Hooker, C. I. L. (2013).

Psychosis-proneness and the rubber hand illusion of body ownership.

Psychiatry Research, 207(1-2), 45-52.

URL     PMID:23273611      Magsci     [本文引用: 1]

Psychosis and psychosis-proneness are associated with abnormalities in subjective experience of the self, including distortions in bodily experience that are difficult to study experimentally due to lack of structured methods. In 55 healthy adults, we assessed the relationship between self-reported psychosis-like characteristics and susceptibility to the rubber hand illusion of body ownership. In this illusion, a participant sees a rubber hand being stroked by a brush at the same time that they feel a brush stroking their own hand. In some individuals, this creates the bodily sense that the rubber hand is their own hand. Individual differences in positive (but not negative) psychosis-like characteristics predicted differences in susceptibility to experiencing the rubber hand illusion. This relationship was specific to the subjective experience of rubber hand ownership, and not other unusual experiences or sensations, and absent when a small delay was introduced between seeing and feeling the brush stroke. This indicates that individual differences in susceptibility are related to visual actile integration and cannot be explained by differences in the tendency to endorse unusual experiences. Our findings suggest that susceptibility to body representation distortion by sensory information may be related or contribute to the development of psychosis and positive psychosis-like characteristics.

Glenberg A. M., Witt J. K., & Metcalfe J . (2013).

From the revolution to embodiment 25 years of cognitive psychology.

Perspectives on Psychological Science, 8(5), 573-585.

URL     PMID:26173215      [本文引用: 1]

In 1988, the cognitive revolution had become institutionalized: Cognition was the manipulation of abstract symbols by rules. But, much like institutionalized political parties, some of the ideas were becoming stale. Where was action? Where was the self? How could cognition be smoothly integrated with emotions, with social psychology, with development, with clinical analyses? Around that time, thinkers in linguistics, philosophy, artificial intelligence, biology, and psychology were formulating the idea that just as overt behavior depends on the specifics of the body in action, so might cognition depend on the body. Here we characterize (some would say caricature) the strengths and weaknesses of cognitive psychology of that era, and then we describe what has come to be called embodied cognition: how cognition arises through the dynamic interplay of brain controlling bodily action controlling perception, which changes the brain. We focus on the importance of action and how action shapes perception, the self, and language. Having the body in action as a central consideration for theories of cognition promises, we believe, to help unify psychology.

Grynberg D., & Pollatos O. (2015).

Alexithymia modulates the experience of the rubber hand illusion.

Frontiers in Human Neuroscience, 9, 357.

URL     PMID:4471366      [本文引用: 2]

Alexithymia is associated with lower awareness of emotional and non-emotional internal bodily signals. However, evidence suggesting that alexithymia modulates body awareness at an external level is scarce. This study aimed to investigate whether alexithymia is associated with disrupted multisensory integration by using the rubber hand illusion task. Fifty healthy individuals completed the Toronto Alexithymia Scale and underwent the rubber hand illusion measure. In this measure, one watches a rubber hand being stroked synchronously or asynchronously with one own hand, which is hidden from view. Compared to the asynchronous stimulation, the synchronous stimulation results in the illusion that the rubber hand and the participant hand are closer together than they really are and that the rubber hand belongs to them. Results revealed that higher levels of alexithymia are associated with a lower ownership illusion. In conclusion, our findings demonstrate that high alexithymia scorers integrate two simultaneous sensory and proprioceptive events into a single experience (lower multisensory integration) to a lesser extent than low alexithymia scorers. Higher susceptibility to the illusion in high alexithymia scorers may -indicate that alexithymia is associated with impaired multisensory integration and that this association results from an abnormal focus of one's own body.

Guterstam A., Abdulkarim Z., & Ehrsson H. H . (2015).

Illusory ownership of an invisible body reduces autonomic and subjective social anxiety responses.

Scientific Reports, 5(1), 9831-9831.

URL     PMID:4407500      [本文引用: 1]

What is it like to be invisible? This question has long fascinated man and has been the central theme of many classic literary works. Recent advances in materials science suggest that invisibility cloaking of the human body may be possible in the not-so-distant future. However, it remains unknown how invisibility affects body perception and embodied cognition. To address these questions, we developed a perceptual illusion of having an entire invisible body. Through a series of experiments, we characterized the multisensory rules that govern the elicitation of the illusion and show that the experience of having an invisible body reduces the social anxiety response to standing in front of an audience. This study provides an experimental model of what it is like to be invisible and shows that this experience affects bodily self-perception and social cognition.

Guterstam A., Petkova V. I., & Ehrsson H. H . (2011).

The illusion of owning a third arm.

PLoS One, 6(2), e17208.

URL     PMID:21383847      [本文引用: 1]

Could it be possible that, in the not-so-distant future, we will be able to reshape the human body so as to have extra limbs? A third arm helping us out with the weekly shopping in the local grocery store, or an extra artificial limb assisting a paralysed person? Here we report a perceptual illusion in which a rubber right hand, placed beside the real hand in full view of the participant, is perceived as a supernumerary limb belonging to the participant's own body. This effect was supported by questionnaire data in conjunction with physiological evidence obtained from skin conductance responses when physically threatening either the rubber hand or the real one. In four well-controlled experiments, we demonstrate the minimal required conditions for the elicitation of this “supernumerary hand illusion”. In the fifth, and final experiment, we show that the illusion reported here is qualitatively different from the traditional rubber hand illusion as it is characterised by less disownership of the real hand and a stronger feeling of having two right hands. These results suggest that the artificial hand ‘borrows’ some of the multisensory processes that represent the real hand, leading to duplication of touch and ownership of two right arms. This work represents a major advance because it challenges the traditional view of the gross morphology of the human body as a fundamental constraint on what we can come to experience as our physical self, by showing that the body representation can easily be updated to incorporate an additional limb.

Guterstam A., Zeberg H., Özçiftci V. M., & Ehrsson H. H . (2016).

The magnetic touch illusion: A perceptual correlate of visuo-tactile integration in peripersonal space.

Cognition 155, 44-56.

URL     PMID:27348406      [本文引用: 1]

To accurately localize our limbs and guide movements toward external objects, the brain must represent the body and its surrounding (peripersonal) visual space. Specific multisensory neurons encode peripersonal space in the monkey brain, and neurobehavioral studies have suggested the existence of a similar representation in humans. However, because peripersonal space lacks a distinct perceptual correlate, its involvement in spatial and bodily perception remains unclear. Here, we show that applying brushstrokes in mid-air at some distance above a rubber hand—without touching it—in synchrony with brushstrokes applied to a participant’s hidden real hand results in the illusory sensation of a “magnetic force” between the brush and the rubber hand, which strongly correlates with the perception of the rubber hand as one’s own. In eight experiments, we characterized this “magnetic touch illusion” by using quantitative subjective reports, motion tracking, and behavioral data consisting of pointing errors toward the rubber hand in an intermanual pointing task. We found that the illusion depends on visuo-tactile synchrony and exhibits similarities with the visuo-tactile receptive field properties of peripersonal space neurons, featuring a non-linear decay at 40cm that is independent of gaze direction and follows changes in the rubber hand position. Moreover, the “magnetic force” does not penetrate physical barriers, thus further linking this phenomenon to body-specific visuo-tactile integration processes. These findings provide strong support for the notion that multisensory integration within peripersonal space underlies bodily self-attribution. Furthermore, we propose that the magnetic touch illusion constitutes a perceptual correlate of visuo-tactile integration in peripersonal space.

Haans A., IJsselsteijn W. A ., & de Kort, Y. A. (2008).

The effect of similarities in skin texture and hand shape on perceived ownership of a fake limb.

Body Image, 5(4), 389-394.

URL     PMID:18650135      Magsci     [本文引用: 1]

In the rubber-hand illusion (RHI), people attribute an artificial object to their own body. In the present study, we investigate the extent to which RHI is affected by visual discrepancies between the artificial object and a human hand. We tested Armel and Ramachandran's (2003) hypothesis that people will experience a stronger RHI when the artificial object is a skin-like textured sheet instead of a tabletop. We did not find support for their hypothesis, but the strength of the RHI diminished when the texture of a hand-shaped object did not resemble the human skin (manipulated by putting a white glove over the cosmetic prosthesis). We provide an alternative explanation for this finding, based on a skill-based sensorimotor account of perceived body ownership. Such an explanation supports Armel and Ramachandran's more general claim that discrepancies in the nature of expected and felt touch diminish the RHI.

Haans A., Kaiser F. G., Bouwhuis D. G., & IJsselsteijn W. A . (2012).

Individual differences in the rubber-hand illusion: Predicting self-reports of people’s personal experiences.

Acta Psychologica, 141(2), 169-177.

URL     PMID:22964058      Magsci     [本文引用: 1]

78 We model 22 experiences related to the rubber-hand illusion using Rasch models. 78 The invariant order in the experiences reflects person-independent cognitive demands. 78 A single ability determines how people experience the rubber-hand illusion.. 78 In an extended model we include the constraints imposed by the experimental setup. 78 Asynchrony and stimulation type (stroke vs. tap) constrain the rubber-hand illusion.

Ide M. . (2013).

The effect of “anatomical plausibility” of hand angle on the rubber-hand illusion.

Perception, 42(1), 103-111.

URL     PMID:23678620      [本文引用: 2]

In the rubber-hand illusion (RHI), when an actual hand hidden from view and a rubber hand in view are simultaneously stimulated, participants mistakenly perceive tactile sensation as arising from the rubber hand, not from the actual hand. Some studies have revealed that the magnitude of RHI decreases when the actual and rubber hand are incongruent in terms of hand angle. However, the acceptable range of angular deviations between the actual and rubber hand and its determination factor has not been investigated so far. I attempt to examine the angle-congruency effect between the actual and rubber hands on RHI. The left rubber hand simulated by 3-D computer graphics was rotated at 8 angles. Participants perceived higher ownership of the stimulated rubber hand when the angles were at 0 degrees, 45 degrees, 90 degrees, and 315 degrees (these are easy to mimic with the actual hand) than at 180 degrees, 225 degrees, and 270 degrees (these are difficult to mimic with the actual hand). The perceived location of the actual hand became closer to that of the simulated rubber hand with increased perception of ownership of the rubber hand. Moreover, the onset duration of RHI became shorter, especially for the angles of 0 degrees, 45 degrees, and 315 degrees. These results suggest that RHI occurs mainly within the range where people usually rotate their hand and that body representation might include the knowledge of "anatomical plausibility".

Ide M., & Wada M. (2016).

Periodic visuotactile stimulation slowly enhances the rubber hand illusion in individuals with high autistic traits.

Frontiers in Integrative Neuroscience, 10, 21.

URL     PMID:4899459      [本文引用: 1]

In a rubber hand illusion (RHI) task, synchronous brush stroking of a rubber hand and a participant's hidden hand induces body ownership of the rubber hand. The effects of spatial distances and temporal lags on the RHI have been extensively examined; however, the effect of periodicity of the stimuli on illusory body ownership has not been examined. Meanwhile, the occurrence of RHI tends to be weak in individuals with autism-spectrum disorders (ASD) and high autistic traits. Preference for stimulus having regularity of tempo is generally observed in individuals with ASD, and thus, periodic stimulation might be more effective to elicit the body ownership illusion in individuals with high autistic traits. Hence, we investigated whether stimulus periodicity influenced RHI as well as its association with participant's autistic traits. Brush strokes were applied to a participant's own hand and the rubber hand periodically (2 s) or non-periodically (13 s), either synchronously or asynchronously. Two blocks were performed in each condition. We found that periodic stimulation enhanced the spatial updating of tactile sensation induced by RHI in the subsequent block in participants with high autistic traits, whereas both periodic and non-periodic stimulation strongly elicited RHI in blocks 1 and 2. These results indicate that the periodicity of stimulation has different effects based on an individual's autistic traits. Since individuals with ASD are known to sustain their focus on interoceptive sensations (heartbeats), a periodic stimulation that is potentially correlated with heartbeats might be effective to enhance the visuotactile integration during RHI in individuals with high autistic traits.

Ionta S., Heydrich L., Lenggenhager B., Mouthon M., Fornari E., Chapuis D ., et al. Blanke, O. (2011).

Multisensory mechanisms in temporo-parietal cortex support self-location and first-person perspective.

Neuron, 70(2), 363-374.

URL     PMID:21521620      Magsci    

78 Neuroscience robotics handles self-location and first-person perspective in fMRI 78 fMRI reveals the central role of TPJ in self-location and first-person perspective 78 Lesion analysis confirms the role of TPJ and suggests a right lateralization

Jackson S. R., Buxbaum L. J., & Coslett H. B . (2011).

Cognitive neuroscience of bodily representations: Psychological processes and neural mechanisms.

Cognitive Neuroscience, 2(34), 135-137.

URL     PMID:24168527      [本文引用: 1]

The past decade has seen increasing interest within the cognitive neuroscience community in understanding the psychological processes involved in representing the body, and in learning how these processes may be implemented within the brain. This special issue of Cognitive Neuroscience presents six new empirical papers that contribute to this rapidly developing literature, together with two theoretical discussion papers that are accompanied by peer commentaries.

Jalal B., Krishnakumar D., & Ramachandran V. S . (2015).

“I feel contaminated in my fake hand”: Obsessive- compulsive-disorder like disgust sensations arise from dummy during rubber hand illusion.

PLoS One, 10(12), e0139159.

URL     PMID:4671689      [本文引用: 1]

Despite its theoretical and clinical interest, there are no experimental studies exploring obsessive-compulsive disorder (OCD)-like disgust sensations through using somatosensory illusions. Such illusions provide important clues to the nature and limits of multisensory integration and how the brain constructs body image; and may potentially inform novel therapies. One such effect is the rubber hand illusion (RHI) in which tactile sensations are referred to a rubber hand; if the experimenter simultaneously strokes a subject occluded hand together with a visible fake hand, the subject starts experiencing the touch sensations as arising from the dummy. In this study, we explore whether OCD-like disgust may result from contamination of a dummy hand during the RHI; suggesting a possible integration of somatosensory and limbic inputs in the construction of body image. We predicted that participants would experience sensations of disgust, when placing a disgust stimulus (fake feces, vomit or blood) on the dummy hand after establishing the RHI. We found that 9 out of 11 participants experienced greater disgust during the synchronous condition (real hidden hand and fake hand are stroked in synchrony) compared to the asynchronous control condition (real hidden hand and fake hand are stroked in asynchrony); and on average such disgust was significantly greater during the synchronous condition compared to the asynchronous control condition,Z= 2.7,p= .008. These results argue against a strictly hierarchical modular approach to brain function and suggest that a four-way multisensory interaction occurs between vision, touch, proprioception on the one hand and primal emotions like disgust on the other. These findings may inform novel clinical approaches for OCD; that is, contaminating a dummy during the RHI could possibly be used as part of an in-vivo exposure-intervention for OCD.

Jeannerod M. . (2003).

The mechanism of self-recognition in humans.

Behavioural Brain Research, 142(1-2), 1-15.

URL     PMID:12798261      [本文引用: 2]

Recognizing oneself as the owner of a body and the agent of actions requires specific mechanisms which have been elucidated only recently. One of these mechanisms is the monitoring of signals arising from bodily movements, i.e. the central signals which contribute to the generation of the movements and the sensory signals which arise from their execution. The congruence between these two sets of signals is a strong index for determining the experiences of ownership and agency, which are the main constituents of the experience of being an independent self. This mechanism, however, does not account from the frequent cases where an intention is generated but the corresponding action is not executed. In this paper, it is postulated that such covert actions are internally simulated by activating specific cortical networks or representations of the intended actions. This process of action simulation is also extended to the observation and the recognition of actions performed or intended by other agents. The problem of disentangling representations that pertain to self-intended actions from those that pertain to actions executed or intended by others, is a critical one for attributing actions to their respective agents. Failure to recognize one own actions and misattribution of actions may result from pathological conditions which alter the readability of these representations.

Jenkinson P. M., Haggard P., Ferreira N. C., & Fotopoulou A . (2013).

Body ownership and attention in the mirror: Insights from somatoparaphrenia and the rubber hand illusion.

Neuropsychologia, 51(8), 1453-1462.

[本文引用: 1]

Kállai J., Hegedüs G., Feldmann Á., Rózsa S., Darnai G., Herold R., .. Szolcsányi T . (2015).

Temperament and psychopathological syndromes specific susceptibility for rubber hand illusion.

Psychiatry Research, 229(1), 410-419.

URL    

61The synchronous visuo-tactile stimulation generated proprioceptive drift predicts high values on novelty seeking and low values on harm avoidance.61The synchronous ownership predict high scores on symptom check list, especially in interpersonal sensitivity, paranoid ideation and psychoticism.61The openness to unusual and strange experiences linked to elevated permeability in one's own body boundary.

Kalckert A., & Ehrsson H. (2017).

The onset time of the ownership sensation in the moving rubber hand illusion.

Frontiers in Psychology, 8, 344.

URL     PMID:5345084      [本文引用: 1]

The rubber hand illusion (RHI) is a perceptual illusion whereby a model hand is perceived as part of one own body. This illusion has been extensively studied, but little is known about the temporal evolution of this perceptual phenomenon, i.e., how long it takes until participants start to experience ownership over the model hand. In the present study, we investigated a version of the rubber hand experiment based on finger movements and measured the average onset time in active and passive movement conditions. This comparison enabled us to further explore the possible role of intentions and motor control processes that are only present in the active movement condition. The results from a large group of healthy participants (n= 117) showed that the illusion of ownership took approximately 23 s to emerge (active: 22.8; passive: 23.2). The 90th percentile occurs in both conditions within approximately 50 s (active: 50; passive: 50.6); therefore, most participants experience the illusion within the first minute. We found indirect evidence of a facilitatory effect of active movements compared to passive movements, and we discuss these results in the context of our current understanding of the processes underlying the moving RHI.

Kalckert A., &Ehrsson H.H . (2014).

The moving rubber hand illusion revisited: Comparing movements and visuotactile stimulation to induce illusory ownership.

Consciousness and Cognition, 26, 117-132.

URL     PMID:24705182      [本文引用: 1]

The rubber hand illusion is a perceptual illusion in which a model hand is experienced as part of one own body. In the present study we directly compared the classical illusion, based on visuotactile stimulation, with a rubber hand illusion based on active and passive movements. We examined the question of which combinations of sensory and motor cues are the most potent in inducing the illusion by subjective ratings and an objective measure (proprioceptive drift). In particular, we were interested in whether the combination of afferent and efferent signals in active movements results in the same illusion as in the purely passive modes. Our results show that the illusion is equally strong in all three cases. This demonstrates that different combinations of sensory input can lead to a very similar phenomenological experience and indicates that the illusion can be induced by any combination of multisensory information.

Keizer A., Smeets M. A., Postma A., van Elburg A., & Dijkerman H. C . (2014).

Does the experience of ownership over a rubber hand change body size perception in anorexia nervosa patients?

Neuropsychologia, 62, 26-37.

URL     PMID:25050852      [本文引用: 1]

61AN patients are more sensitive than HC to experience ownership over a fake hand.61AN patients overestimate own hand width but correctly estimate width of a fake hand.61After induction of the RHI, AN patients no longer overestimate their hand width.61This was found under the synchronous and asynchronous (control) conditions of the RHI.

Knoblich G., Thornton I., Grosjean M. , & Shiffrar, M.(2006) . Human body perception from the inside out. New York: Oxford University Press.

[本文引用: 1]

Lane T., Yeh S.-L., Tseng P., & Chang A.-Y . (2017).

Timing disownership experiences in the rubber hand illusion.

Cognitive Research, 2(1), 4.

URL     PMID:5281674      [本文引用: 1]

Some investigators of the rubber hand illusion (RHI) have suggested that when standard RHI induction procedures are employed, if the rubber hand is experienced by participants as owned, their corresponding biological hands are experienced as disowned. Others have demurred: drawing upon a variety of experimental data and conceptual considerations, they infer that experience of the RHI might include the experience of a supernumerary limb, but that experienced disownership of biological hands does not occur. Indeed, some investigators even categorically deny that any experimental paradigm has been employed or any evidence can be adduced to support the claim that disownership experiences occur during the RHI. It goes without saying that RHI experiences can be elusive, and that there is some evidence to support claims that supernumerary limb experiences can sometimes occur. Here, however, we test the claim that the conscious experience of disownership can occur during the RHI. In order to test this claim, we developed two new online proxies nset time for the illusion and illusion durationnd combined these with established questionnaires that concern the conscious contents of the RHI, in particular ownership/disownership experiences. Both online proxy data and post hoc questionnaire data converge in supporting the claim that disownership experiences do occur, at least when the left hand is the object of investigation. Our findings that onset time and illusion duration are reliable measures suggest that investigations of the RHI stand to benefit by devoting more attention to data collected while the RHI is being experienced, in particular data concerning temporal dynamics.

Lee I.-S., & Chae Y. (2016).

Neural network underlying recovery from disowned bodily states induced by the rubber hand illusion.

Neural Plasticity, 2016, 8307175.

URL     PMID:5223049      [本文引用: 1]

We used functional magnetic resonance imaging to investigate how causal influences between brain regions during the rubber hand illusion (RHI) are modulated by tactile and visual stimuli. We applied needle rotations during the RHI in two different ways: one was with the real hand (reinstantiation by tactile stimuli, R-TS) and the other was with the rubber hand (reinstantiation by visual stimuli, R-VS). We used dynamic causal modeling to investigate interactions among four relevant brain regions: the ventral premotor cortex (PMv), the intraparietal sulcus (IPS), the secondary somatosensory cortex (SII), and the lateral occipitotemporal cortex (LOC). The tactile aspects of needle rotations changed the effective connectivity by directly influencing activity in the SII, whereas visual aspects of needle rotation changed the effective connectivity by influencing both the SII and the LOC. The endogenous connectivity parameters between the IPS and the PMv were reduced significantly in the R-TS condition. The modulatory parameters between the IPS and the PMv were enhanced significantly in the R-TS condition. The connectivity patterns driven by disowned bodily states could be differentially modulated by tactile and visual afferent inputs. Effective connectivity between the parietal and frontal multimodal areas may play important roles in the reinstantiation of body ownership.

Lev-Ari L., Hirschmann S., Dyskin O., Goldman O., & Hirschmann I . (2015).

The Rubber Hand Illusion paradigm as a sensory learning process in patients with schizophrenia.

European Psychiatry, 30(7), 868-873.

URL     PMID:26443055      [本文引用: 1]

The Rubber Hand Illusion (RHI) has previously been used to depict the hierarchy between visual, tactile and perceptual stimuli. Studies on schizophrenia inpatients (SZs) have found mixed results in the ability to first learn the illusion, and have yet to explain the learning process involved. This study's aim was two-fold: to examine the learning process of the RHI in SZs and healthy controls over time, and to better understand the relationship between psychotic symptoms and the RHI. Thirty schizophrenia inpatients and 30 healthy controls underwent five different trials of the RHI over a two-week period. As has been found in previous studies, SZs felt the initial illusion faster than healthy controls did, but their learning process throughout the trials was inconsistent. Furthermore, for SZs, no correlations between psychotic symptoms and the learning of the illusion emerged. Healthy individuals show a delayed reaction to first feeling the illusion (due to latent inhibition), but easily learn the illusion over time. For SZs, both strength of the illusion and the ability to learn the illusion over time are inconsistent. The cognitive impairment in SZ impedes the learning process of the RHI, and SZs are unable to utilize the repetition of the process as healthy individuals can.

Limanowski J., & Blankenburg F. (2016).

That’s not quite me: Limb ownership encoding in the brain.

Social Cognitive and Affective Neuroscience, 11(7), 1130-1140.

URL     PMID:4927034      [本文引用: 2]

With congruent stimulation of one's limb together with a fake counterpart, an illusory self-attribution of the fake limb can be induced. Such have brought profound insights into the cognitive and neuronal mechanisms underlying temporary changes in body representation, but to put them in perspective they need to be compared with ownership as experienced for one's real body. We used fMRI to compare the neuronal correlates of touch under different degrees of body ownership. Participants' left and right arms were stimulated either alone, or together with a fake counterpart while this stimulation was either synchronous, ambiguous, or asynchronous. Synchronous stimulation induced illusory fake arm ownership, but the brain still differentiated between touch to one's real arm and to an illusory "owned" arm: the degree of arm ownership was encoded positively by activity in the ventromedial prefrontal cortex and lateral occipitotemporal cortex, and negatively in the temporoparietal cortex. Conversely, the ventral premotor cortex responded more strongly to synchronous stimulation compared with asynchronous stimulation and with real arm only stimulation. These results offer new insights into the differential representation of the real body versus a body that is temporarily self-attributed following the resolution of multisensory conflict.

Lira M., Egito J. H., Dall’Agnol P. A., Amodio D. M., Gonçalves Ó. F., & Boggio P. S . (2017).

The influence of skin colour on the experience of ownership in the rubber hand illusion.

Scientific Reports, 7(1), 15745.

URL     PMID:29147006      [本文引用: 1]

Abstract Racial prejudice is associated with a fundamental distinction between "us" and "them"-a distinction linked to the perceived overlap between representations of the self and others. Implicit prejudice has been shown to reduce the intensity of White individuals' hand ownership sensation as induced by the Rubber Hand Illusion (RHI) with dark rubber hands. However, evidence for this link to implicit prejudice comes from self-report questionnaire data regarding the RHI. As an alternative, we assessed the onset time of the RHI. We hypothesized that onset time of the RHI would be higher for the black compared to the white RH, acting as the mediator between implicit prejudice and magnitude of the RH illusion and proprioceptive drift. As expected, participants took longer to incorporate the black RH and presented lower RH illusion magnitude and a smaller proprioceptive drift for the black RH. Mediation analysis revealed a significant indirect effect of implicit racial bias on proprioceptive drift and magnitude of illusion through onset time to illusion only for the black RH. These findings further illuminate the connection between implicit prejudice and embodied perception, suggesting new perspectives on how implicit biases operate.

Lloyd D.M . (2007).

Spatial limits on referred touch to an alien limb may reflect boundaries of visuo-tactile peripersonal space surrounding the hand.

Brain and Cognition, 64(1), 104-109.

URL     PMID:17118503      Magsci     [本文引用: 1]

In this study, the spatial limits of referred touch to a rubber hand were investigated. Participants rated the strength of the perceived illusion when the rubber hand was placed in one of six different spatial positions (at a distance of 17.5–67.5 cm horizontal from the participant’s own hand). The results revealed a significant nonlinear relationship in the strength of the illusion, with the strongest ratings given when the two hands were closest; decaying significantly after a distance of 30 cm. The time taken to elicit the illusion followed a similar trend. These results may reflect the response properties of bimodal visuo-tactile cells encoding peripersonal space around the hand.

Ma K., & Hommel B. (2013).

The virtual-hand illusion: Effects of impact and threat on perceived ownership and affective resonance.

Frontiers in Psychology, 4, 604.

URL     PMID:24046762      [本文引用: 2]

The rubber hand illusion refers to the observation that participants perceive “body ownership” for a rubber hand if it moves, or is stroked in synchrony with the participant’s real (covered) hand. Research indicates that events targeting artificial body parts can trigger affective responses (affective resonance) only with perceived body ownership, while neuroscientific findings suggest affective resonance irrespective of ownership (e.g., when observing other individuals under threat). We hypothesized that this may depend on the severity of the event. We first replicated previous findings that the rubber hand illusion can be extended to virtual hands—the virtual-hand illusion. We then tested whether hand ownership and affective resonance (assessed by galvanic skin conductance) are modulated by the experience of an event that either “impacted” (a ball hitting the hand) or “threatened” (a knife cutting the hand) the virtual hand. Ownership was stronger if the virtual hand moved synchronously with the participant’s own hand, but this effect was independent from whether the hand was impacted or threatened. Affective resonance was mediated by ownership however: In the face of mere impact, participants showed more resonance in the synchronous condition (i.e., with perceived ownership) than in the asynchronous condition. In the face of threat, in turn, affective resonance was independent of synchronicity—participants were emotionally involved even if a threat was targeting a hand that they did not perceive as their own. Our findings suggest that perceived body ownership and affective responses to body-related impact or threat can be dissociated and are thus unlikely to represent the same underlying process. We argue that affective reactions to impact are produced in a top-down fashion if the impacted effector is assumed to be part of one’s own body, whereas threatening events trigger affective responses more directly in a bottom-up fashion—irrespective of body ownership.

Ma K., & Hommel B. (2015).

Body-ownership for actively operated non-corporeal objects.

Consciousness and Cognition, 36, 75-86.

URL     PMID:26094223      [本文引用: 1]

Rubber-hand and virtual-hand illusions show that people can perceive body ownership for objects under suitable conditions. Bottom-up approaches assume that perceived ownership emerges from multisensory matching (e.g., between seen object and felt hand movements), whereas top-down approaches claim that novel body parts are integrated only if they resemble some part of a permanent internal body representation. We demonstrate that healthy adults perceive body ownership for a virtual balloon changing in size, and a virtual square changing in size or color, in synchrony with movements of their real hand. This finding is inconsistent with top-down approaches and amounts to an existence proof that non-corporeal events can be perceived as body parts if their changes are systematically related to one actions. It also implies that previous studies with passive-stimulation techniques might have underestimated the plasticity of body representations and put too much emphasis on the resemblance between viewed object and real hand.

Makin T. R., Holmes N. P., & Ehrsson H. H . (2008).

On the other hand: Dummy hands and peripersonal space.

Behavioural Brain Research, 191(1), 1-10.

URL     PMID:18423906      [本文引用: 1]

Where are my hands? The brain can answer this question using sensory information arising from vision, proprioception, or touch. Other sources of information about the position of our hands can be derived from multisensory interactions (or potential interactions) with our close environment, such as when we grasp or avoid objects. The pioneering study of multisensory representations of peripersonal space was published in Behavioural Brain Research almost 30 years ago [Rizzolatti G, Scandolara C, Matelli M, Gentilucci M. Afferent properties of periarcuate neurons in macaque monkeys. II. Visual responses. Behav Brain Res 1981;2:147–63]. More recently, neurophysiological, neuroimaging, neuropsychological, and behavioural studies have contributed a wealth of evidence concerning hand-centred representations of objects in peripersonal space. This evidence is examined here in detail. In particular, we focus on the use of artificial dummy hands as powerful instruments to manipulate the brain's representation of hand position, peripersonal space, and of hand ownership. We also review recent studies of the ‘rubber hand illusion’ and related phenomena, such as the visual capture of touch, and the recalibration of hand position sense, and discuss their findings in the light of research on peripersonal space. Finally, we propose a simple model that situates the ‘rubber hand illusion’ in the neurophysiological framework of multisensory hand-centred representations of space.

Makin T. R., Holmes N. P., & Zohary E . (2007).

Is that near my hand? Multisensory representation of peripersonal space in human intraparietal sulcus.

Journal of Neuroscience, 27(4), 731-740.

URL     PMID:17251412      [本文引用: 1]

Abstract Our ability to interact with the immediate surroundings depends not only on an adequate representation of external space but also on our ability to represent the location of objects with respect to our own body and especially to our hands. Indeed, electrophysiological studies in monkeys revealed multimodal neurons with spatially corresponding tactile and visual receptive fields in a number of brain areas, suggesting a representation of visual peripersonal space with respect to the body. In this functional magnetic resonance imaging study, we localized areas in human intraparietal sulcus (IPS) and lateral occipital complex (LOC) that represent nearby visual space with respect to the hands (perihand space), by contrasting the response to a ball moving near-to versus far-from the hands. Furthermore, by independently manipulating sensory information about the hand, in the visual (using a dummy hand) and proprioceptive domains (by changing the unseen hand position), we determined the sensory contributions to the representation of hand-centered space. In the posterior IPS, the visual contribution was dominant, overriding proprioceptive information. Surprisingly, regions within LOC also displayed visually dominant, hand-related activation. In contrast, the anterior IPS was characterized by a proprioceptive representation of the hand, as well as showing tactile hand-specific activation, suggesting a homology with monkey parietal hand-centered areas. We therefore suggest that, whereas cortical regions within the posterior IPS and LOC represent hand-centered space in a predominantly visual manner, the anterior IPS uses multisensory information in representing perihand space.

Marotta A., Tinazzi M., Cavedini C., Zampini M., & Fiorio M . (2016).

Individual differences in the rubber hand illusion are related to sensory suggestibility.

PLoS One, 11(12), e0168489.

URL     [本文引用: 1]

In the rubber hand illusion (RHI), watching a rubber hand being stroked in synchrony with one own hidden hand may induce a sense of ownership over the rubber hand. The illusion relies on bottom-up multisensory integration of visual, tactile, and proprioceptive information, and on top-down processes through which the rubber hand is incorporated into pre-existing representations of the body. Although the degree of illusory experience varies largely across individuals, the factors influencing individual differences are unknown. We investigated whether sensory suggestibility might modulate susceptibility to the RHI. Sensory suggestibility is a personality trait related to how individuals react to sensory information. Because of its sensory nature, this trait could be relevant for studies using the RHI paradigm. Seventy healthy volunteers were classified by Sensory Suggestibility Scale (SSS) scores as having high or low suggestibility and assigned to either a high- (High-SSS) or a low-suggestibility (Low-SSS) group. Two components of the RHI were evaluated in synchronous and asynchronous stroking conditions: subjective experience of sense of ownership over the rubber hand via a 9-statement questionnaire, and proprioceptive drift as measured with a ruler. The High-SSS group was generally more susceptible to the subjective component; in the synchronous condition, they rated the statement assessing the sense of ownership higher than the Low-SSS group. The scores for this statement significantly correlated with the total SSS score, indicating that the higher the sensory suggestibility, the stronger the sense of ownership. No effect of sensory suggestibility on proprioceptive drift was observed, suggesting that the effect is specific for the subjective feeling of ownership. This study demonstrates that sensory suggestibility may contribute to participants experience of the illusion and should be considered when using the RHI paradigm.

Mirucka B. . (2016).

The sense of body ownership in schizophrenia: Research in the rubber hand illusion paradigm.

Psychiatria Polska, 50(4), 731-740.

URL     PMID:27847924      [本文引用: 1]

Abstract Aim. The aim of the research was to explore the susceptibility to disturbances in one's sense of body ownership induced in patients with schizophrenia. The research questions were: 1) Is Rubber Hand Illusion (RHI) significantly more intense in a group of patients with schizophrenia than in a group of patients without a diagnosed mental illness? 2) Is there a correlation between disturbances in the sense of body ownership and the personality organization level, reflected in defense mechanisms? 3) Do the disturbances in the sense of body ownership correlate with the most common defense mechanisms? Methods. 64 people took part in the study, including 31 patients with diagnosed schizophrenia, according to ICD-10 (93.5% paranoid type and 6.5% disorganized type) and 33 people without mental illness diagnosis. The study was conducted in the RHI paradigm. Research tools used: Botvinick and Cohen's RHI Questionnaire and Bond's Defense Style Questionnaire. Results. There were significant differences between the control group and the schizophrenic group: 1) in the intensity of MI (F(1, 62) = 121.86; p < 0.001), as well as 2) on the neurotic (F(1, 62) = 28.21; p < 0.001) and immature (F(1, 62) = 36.71; p < 0.001) mechanisms' level. Patients witch schizophrenia activated immature mechanisms most intensively while in the control group the dominant mechanisms were from mature and neurotic groups. Conclusions. Patients with schizophrenia experience disruptions in the sense of body ownership much more intensively compared to the control group. The intensity of RHI is related to the personality organization level and to the most common activation of mechanisms from immature group, especially schizoid fantasy and projection.

Ocklenburg S., Peterburs J., Rüther N., & Güntürkün O . (2012).

The rubber hand illusion modulates pseudoneglect.

Neuroscience Letters, 523(2), 158-161.

URL     PMID:22771568      Magsci     [本文引用: 1]

The rubber hand illusion (RHI) refers to the illusory perception of ownership of a rubber hand that may occur when covert tactile stimulation of a participant's hand co-occurs with overt corresponding stimulation of a rubber hand. It is proposed that integrating the rubber hand into one's body image may shift the subjective body midline away from the rubber hand. The present study investigated the influence of the RHI on pseudoneglect on the line bisection task, i.e. the leftward bias when marking the centre of horizontal lines, in 79 neurologically healthy adults. Overall, pseudoneglect was reduced after RHI application. Importantly, this effect was specific for individuals who reported having vividly experienced the illusion (high responders) as opposed to individuals who did not (low responders). Moreover, pseudoneglect was eliminated only after RHI application to the left hand. This pattern of results is consistent with functional hemispheric asymmetry for spatial processing and suggests that integrating the left sided rubber hand into one's body image shifts the subjective body midline to the right, thus counteracting pseudoneglect.

Olivé I., Tempelmann C., Berthoz A., & Heinze H. J . (2015).

Increased functional connectivity between superior colliculus and brain regions implicated in bodily self-consciousness during the rubber hand illusion.

Human Brain Mapping, 36(2), 717-730.

URL     PMID:25346407      [本文引用: 1]

Abstract Bodily self-consciousness refers to bodily processes operating at personal, peripersonal, and extrapersonal spatial dimensions. Although the neural underpinnings of representations of personal and peripersonal space associated with bodily self-consciousness were thoroughly investigated, relatively few is known about the neural underpinnings of representations of extrapersonal space relevant for bodily self-consciousness. In the search to unravel brain structures generating a representation of the extrapersonal space relevant for bodily self-consciousness, we developed a functional magnetic resonance imaging (fMRI) study to investigate the implication of the superior colliculus (SC) in bodily illusions, and more specifically in the rubber hand illusion (RHi), which constitutes an established paradigm to study the neural underpinnings of bodily self-consciousness. We observed activation of the colliculus ipsilateral to the manipulated hand associated with eliciting of RHi. A generalized form of context-dependent psychophysiological interaction analysis unravelled increased illusion-dependent functional connectivity between the SC and some of the main brain areas previously involved in bodily self-consciousness: right temporoparietal junction (rTPJ), bilateral ventral premotor cortex (vPM), and bilateral postcentral gyrus. We hypothesize that the collicular map of the extrapersonal space interacts with maps of the peripersonal and personal space generated at rTPJ, vPM and the postcentral gyrus, producing a unified representation of space that is relevant for bodily self-consciousness. We suggest that processes of multisensory integration of bodily-related sensory inputs located in this unified representation of space constitute one main factor underpinning emergence of bodily self-consciousness. Hum Brain Mapp 36:717730, 2015. 2014 Wiley Periodicals, Inc.

Paladino M.-P., Mazzurega M., Pavani F., & Schubert T. W . (2010).

Synchronous multisensory stimulation blurs self-other boundaries.

Psychological Science, 21(9), 1202-1207.

URL     PMID:20679523      [本文引用: 1]

Abstract In a study that builds on recent cognitive neuroscience research on body perception and social psychology research on social relations, we tested the hypothesis that synchronous multisensory stimulation leads to self-other merging. We brushed the cheek of each study participant as he or she watched a stranger's cheek being brushed in the same way, either in synchrony or in asynchrony. We found that this multisensory procedure had an effect on participants' body perception as well as social perception. Study participants exposed to synchronous stimulation showed more merging of self and the other than participants exposed to asynchronous stimulation. The degree of self-other merging was determined by measuring participants' body sensations and their perception of face resemblance, as well as participants' judgment of the inner state of the other, closeness felt toward the other, and conformity behavior. The results of this study show how multisensory integration can affect social perception and create a sense of self-other similarity.

Palmer C.E., & Tsakiris M. (2018).

Going at the heart of social cognition: Is there a role for interoception in self-other distinction?

Current Opinion in Psychology, 24, 21-26.

URL     PMID:29704794      [本文引用: 2]

Ramakonar H., Franz E. A., & Lind C. R . (2011).

The rubber hand illusion and its application to clinical neuroscience.

Journal of Clinical Neuroscience, 18(12), 1596-1601.

URL     PMID:22000838      Magsci     [本文引用: 1]

The rubber hand illusion (RHI) is a perceptual experience which often occurs when an administered tactile stimulation of a person’s real hand hidden from view, occurs synchronously with a corresponding visual stimulation of an observed rubber hand placed in full vision of the person in a position corresponding to where their real hand might normally be. The perceptual illusion is that the person feels a sense of “ownership” of the rubber hand which they are looking at. Most studies have focused on the underlying neural properties of the illusion and the experimental manipulations that lead to it. The illusion could also be used for exploring the sense of limb and prosthetic ownership for people after amputation. Cortical electrodes such as those used in sensorimotor stimulation surgery for pain may provide an opportunity to further understand the cortical representation of the illusion and possibly provide an opportunity to modulate the individual’s sense of body ownership. Thus, the RHI might also be a critical tool for development of neurorehabilitative interventions that will be of great interest to the neurosurgical and rehabilitation communities.

Pasqualotto A., &Proulx M.J . (2015).

Two-dimensional rubber-hand illusion: The Dorian Gray hand illusion.

Multisensory Research, 28(1-2), 101-110.

URL     PMID:26152054      [本文引用: 1]

The rubber-hand illusion provides a window into body representation and consciousness. It has been found that body-ownership extended to numerous hand-like objects. Interestingly, the vast majority of these objects were three-dimensional. We adopted this paradigm by using hand drawings to investigate whether rubber-hand illusion could be extended to two-dimensional hand samples, and we measured skin conductance responses and behavioural variables. The fact that this illusion extended to two-dimensional stimuli reveals the dominant role of top-down information on visual perception for body representation and consciousness.

Paton B., Hohwy J., & Enticott P. G . (2012).

The rubber hand illusion reveals proprioceptive and sensorimotor differences in autism spectrum disorders.

Journal of Autism and Developmental Disorders, 42(9), 1870-1883.

URL     PMID:22189963      [本文引用: 1]

Autism spectrum disorder (ASD) is characterised by differences in unimodal and multimodal sensory and proprioceptive processing, with complex biases towards local over global processing. Many of these elements are implicated in versions of the rubber hand illusion (RHI), which were therefore studied in high-functioning individuals with ASD and a typically developing control group. Both groups experienced the illusion. A number of differences were found, related to proprioception and sensorimotor processes. The ASD group showed reduced sensitivity to visuotactile-proprioceptive discrepancy but more accurate proprioception. This group also differed on acceleration in subsequent reach trials. Results are discussed in terms of weak top-down integration and precision-accuracy trade-offs. The RHI appears to be a useful tool for investigating multisensory processing in ASD.

Peled A., Ritsner M., Hirschmann S., Geva A. B., & Modai I . (2000).

Touch feel illusion in schizophrenic patients.

Biological Psychiatry, 48(11), 1105-1108.

URL     [本文引用: 2]

http://linkinghub.elsevier.com/retrieve/pii/S0006322300009471

Reinersmann A., Landwehrt J., Krumova E. K., Peterburs J., Ocklenburg S., Güntürkün O., & Maier C . (2013).

The rubber hand illusion in complex regional pain syndrome: Preserved ability to integrate a rubber hand indicates intact multisensory integration.

Pain, 154(9), 1519-1527.

URL     PMID:23706626     

In patients with complex regional pain syndrome (CRPS) type 1, processing of static tactile stimuli is impaired, whereas more complex sensory integration functions appear preserved. This study investigated higher order multisensory integration of body-relevant stimuli using the rubber hand illusion in CRPS patients. Subjective self-reports and skin conductance responses to watching the rubber hand being harmed were compared among CRPS patients (N=24), patients with upper limb pain of other origin (N=21, clinical control group), and healthy subjects (N=24). Additionally, the influence of body representation (body plasticity [Trinity Assessment of Body Plasticity], neglect-like severity symptoms), and clinical signs of illusion strength were investigated. For statistical analysis, 1-way analysis of variance, t test, Pearson correlation, with 0.05 were used. CRPS patients did not differ from healthy subjects and the control group with regard to their illusion strength as assessed by subjective reports or skin conductance response values. Stronger left-sided rubber hand illusions were reported by healthy subjects and left-side-affected CRPS patients. Moreover, for this subgroup, illness duration and illusion strength were negatively correlated. Overall, severity of neglect-like symptoms and clinical signs were not related to illusion strength. However, patients with CRPS of the right hand reported significantly stronger neglect-like symptoms and significantly lower illusion strength of the affected hand than patients with CRPS of the left hand. The weaker illusion of CRPS patients with strong neglect-like symptoms on the affected hand supports the role of top-down processes modulating body ownership. Moreover, the intact ability to perceive illusory ownership confirms the notion that, despite impaired processing of proprioceptive or tactile input, higher order multisensory integration is unaffected in CRPS.

Petkova V.I., &Ehrsson H.H . (2009).

When right feels left: Referral of touch and ownership between the hands.

PLoS One, 4(9), e6933.

URL     PMID:19742313      [本文引用: 2]

Feeling touch on a body part is paradigmatically considered to require stimulation of tactile afferents from the body part in question, at least in healthy non-synaesthetic individuals. In contrast to this view, we report a perceptual illusion where people experience "phantom touches" on a right rubber hand when they see it brushed simultaneously with brushes applied to their left hand. Such illusory duplication and transfer of touch from the left to the right hand was only elicited when a homologous (i.e., left and right) pair of hands was brushed in synchrony for an extended period of time. This stimulation caused the majority of our participants to perceive the right rubber hand as their own and to sense two distinct touches--one located on the right rubber hand and the other on their left (stimulated) hand. This effect was supported by quantitative subjective reports in the form of questionnaires, behavioral data from a task in which participants pointed to the felt location of their right hand, and physiological evidence obtained by skin conductance responses when threatening the model hand. Our findings suggest that visual information augments subthreshold somatosensory responses in the ipsilateral hemisphere, thus producing a tactile experience from the non-stimulated body part. This finding is important because it reveals a new bilateral multisensory mechanism for tactile perception and limb ownership.

Riemer M., Fuchs X., Bublatzky F., Kleinböhl D., Hölzl R., & Trojan J . (2014).

The rubber hand illusion depends on a congruent mapping between real and artificial fingers.

Acta Psychologica, 152, 34-41.

URL     PMID:25103418     

61Incongruent mapping between real and artificial fingers within the motor RHI.61Application of a new method to modulate predictability of movements/touches.61Congruent mapping between fingers is important, predictability is not.61Deduction of four basic principles for successful embodiment.

Sanchez-Vives M. V., Spanlang B., Frisoli A., Bergamasco M., & Slater M . (2010).

Virtual hand illusion induced by visuomotor correlations.

PLoS One, 5(4), e10381.

URL     PMID:2861624      [本文引用: 2]

Our body schema gives the subjective impression of being highly stable. However, a number of easily-evoked illusions illustrate its remarkable malleability. In the rubber-hand illusion, illusory ownership of a rubber-hand is evoked by synchronous visual and tactile stimulation on a visible rubber arm and on the hidden real arm. Ownership is concurrent with a proprioceptive illusion of displacement of the arm position towards the fake arm. We have previously shown that this illusion of ownership plus the proprioceptive displacement also occurs towards a virtual 3D projection of an arm when the appropriate synchronous visuotactile stimulation is provided. Our objective here was to explore whether these illusions (ownership and proprioceptive displacement) can be induced by only synchronous visuomotor stimulation, in the absence of tactile stimulation.

Scandola M., Tidoni E., Avesani R., Brunelli G., Aglioti S. M., & Moro V . (2014).

Rubber hand illusion induced by touching the face ipsilaterally to a deprived hand: Evidence for plastic “somatotopic” remapping in tetraplegics.

Frontiers in Human Neuroscience, 8, 404.

URL     PMID:4050649     

Background: Studies in animals and humans indicate that the interruption of body-brain connections following spinal cord injury (SCI) leads to plastic cerebral reorganization. Objective: To explore whether inducing the Rubber Hand Illusion (RHI) via synchronous multisensory visuo-tactile bodily stimulation may reveal any perceptual correlates of plastic remapping in SCI. Methods: In 16 paraplegic, 16 tetraplegic and 16 healthy participants we explored whether RHI may be induced by tactile stimuli involving not only the left hand but also the left hemi-face. Touching the participants actual hand or face was either synchronous or asynchronous with tactile stimuli seen on a rubber hand. We assessed two components of the illusion, namely perceived changes in the real hand in space (indexed by proprioceptive drift) and ownership of the rubber hand (indexed by subjective responses to an ad-hoc questionnaire). Results: Proprioceptive drift and ownership were found in the healthy group only in the condition where the left real and fake hand were touched simultaneously. In contrast, no drift was found in the SCI patients who, however, showed ownership after both synchronous and asynchronous hand stroking. Importantly, only tetraplegics showed the effect also after synchronous face stroking. Conclusions: RHI may reveal plastic phenomena in SCI. In hand representation-deprived tetraplegics, stimuli on the face (represented contiguously in the somatic and motor systems), drive the sense of hand ownership. This hand-face remapping phenomenon may be useful for restoring a sense of self in massively deprived individuals.

Schütz-Bosbach S., Tausche P., & Weiss C . (2009).

Roughness perception during the rubber hand illusion.

Brain and Cognition, 70(1), 136-144.

URL     PMID:19231057      Magsci     [本文引用: 1]

Watching a rubber hand being stroked by a paintbrush while feeling identical stroking of one’s own occluded hand can create a compelling illusion that the seen hand becomes part of one’s own body. It has been suggested that this so-called rubber hand illusion (RHI) does not simply reflect a bottom–up multisensory integration process but that the illusion is also modulated by top–down, cognitive factors. Here we investigated for the first time whether the conceptual interpretation of the sensory quality of the visuotactile stimulation in terms of roughness can influence the occurrence of the illusion and vice versa, whether the presence of the RHI can modulate the perceived sensory quality of a given tactile stimulus (i.e., in terms of roughness). We used a classical RHI paradigm in which participants watched a rubber hand being stroked by either a piece of soft or rough fabric while they received synchronous or asynchronous tactile stimulation that was either congruent or incongruent with respect to the sensory quality of the material touching the rubber hand. (In)congruencies between the visual and tactile stimulation did neither affect the RHI on an implicit level nor on an explicit level, and the experience of the RHI in turn did not cause any modulations of the felt sensory quality of touch on participant’s own hand. These findings first suggest that the RHI seems to be resistant to top–down knowledge in terms of a conceptual interpretation of tactile sensations. Second,