Department of Experimental Psychology, University of Oxford, United Kingdom.
Neuropsychologia. 2010 Jan;48(1):26-37. doi: 10.1016/j.neuropsychologia.2009.08.006.
Following stroke, a patient may fail to report touch administered by another person but claim that she feels touch when it is self-administered. We investigated three explanations for self-touch enhancement: (1) proprioceptive information from the administering hand, (2) attentional modulation, and (3) temporal expectation. Tactile sensation was assessed with vision precluded, and with the affected hand positioned in the left and right hemispace. In four of six experiments, the somatic rubber hand paradigm was used: the Examiner administered stimulation to the patient's affected left hand while guiding the patient's right hand to administer synchronous stimulation to a prosthetic hand. Even though the patient's two hands were not in contact, patients detected the same number of stimulations as when they touched their own hand directly (self-administered condition). Moreover, there was no decline in rates of detection when potentially informative movements of the administering hand were restricted. This demonstrates that patients feel rather than infer stimulation under conditions of self-touch. When patients received stimulation to the affected hand in the opposite hemispace to the hand administering touch to the prosthetic hand, all but one showed self-touch enhancement. Thus, neither proprioceptive information nor attentional modulation at the spatial region of the administering hand provided a sufficient explanation for self-touch enhancement. A follow-up experiment indicated an important role for temporal expectation: a delay, between the patient's stimulation of the prosthetic hand and the Examiner's stimulation of the patient's affected hand, eliminated the self-touch enhancement effect.
中风后，患者可能无法报告他人施加的触觉，但当自我施加触觉时，却声称自己感觉到了触觉。我们研究了自我触摸增强的三种解释：（1）来自施力手的本体感觉信息，（2）注意力调节，和（3）时间预期。触觉感觉是在视觉被排除的情况下评估的，并且受影响的手位于左半空间和右半空间。在四个实验中的六个实验中，使用了躯体橡胶手范式：检查者在指导患者的右手对假肢进行同步刺激的同时，对患者的左手施加刺激。即使患者的两只手没有接触，患者也能检测到与直接触摸自己手时相同数量的刺激（自我施加条件）。此外，当限制施力手的潜在信息性运动时，检测率没有下降。这表明，在自我触摸的情况下，患者是感觉到而不是推断刺激的。当患者在与假肢施力手相反的半空间中接受刺激时，除一人外，所有人都表现出自触摸增强。因此，无论是施力手的空间区域的本体感觉信息还是注意力调节都不能充分解释自触摸增强。后续实验表明，时间预期起着重要作用：在患者对假肢进行刺激与检查者对患者受影响的手进行刺激之间的延迟消除了自触摸增强效应。
