Synchronous visuotactile stimulation on the own hidden hand and a visible fake limb can alter bodily self-perception and influence spontaneous neuroplasticity. The rubber hand illusion (RHI) paradigm experimentally produces an illusion of rubber hand ownership and arm shift by simultaneously stroking a rubber hand in view and a participant’s visually occluded hand. The aim of this cross-over, placebo-controlled, single-blind study was to assess whether RHI, in combination with high-frequency repetitive transcranial magnetic stimulation (rTMS) given as intermittent (excitatory) theta burst stimulation (iTBS) applied over the hand area of the primary sensory region (S1) can enhance tactile sensation in a group of 21 healthy subjects and one patient with cervical spinal cord injury. Four sessions covered all combinations of real and sham stimulations of the RHI and the TBS: real TBS and real RHI, real TBS and sham RHI, sham TBS and real RHI, and both conditions sham. The condition sham TBS and real RHI shows the greatest effect on the proprioceptive drift (median 2.3 cm, IQR 2) and on the score of RHI questionnaires (median 3, IQR 2) in the control group as well as in the real-real condition (median 2, IQR 2). The sham TBS and real RHI condition also shows the best results in the electrical perception test of the patient (median 1.9 mA). Conversely, the upregulation of the cortical excitability of S1 via TBS seems to impair the effect of the RHI. This might be due to a strengthening of the top-down connection between the central nervous system and the periphery, diminishing the RHI. This finding helps in understanding the mechanisms of top-down and bottom-up mechanisms in healthy subjects and patients with spinal cord injury. The RHI paradigm could represent an interesting therapeutic approach in improving tactile sensation and rTMS techniques could modulate these effects. Yet, further studies are needed, to examine the direction of the interaction effect of TMS and RH.

中文翻译：

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橡胶手错觉和刺激的θ爆发刺激对触觉的影响：一项初步研究。

自己隐藏的手和可见的假肢上的同步触觉刺激可以改变身体的自我知觉并影响自发性神经可塑性。橡胶手错觉（RHI）范例通过同时抚摸橡胶手和参与者的视觉遮挡手，实验性地产生了橡胶手所有权和手臂移动的错觉。这项交叉，安慰剂对照，单盲研究的目的是评估RHI是否与间歇性（兴奋性）θ爆裂刺激（iTBS）一起应用的高频重复经颅磁刺激（rTMS）相结合。在21名健康受试者和1名颈脊髓损伤患者中，主要感觉区域（S1）的手部区域可增强触感。四个会议涵盖了RHI和TBS的真实刺激和伪刺激的所有组合：真实TBS和真实RHI，真实TBS和伪RHI，伪TBS和真实RHI，以及两种情况的伪。假手术组和真实状态对假肢TBS和真实RHI的影响最大，对本体感受漂移（中位数2.3 cm，IQR 2）和RHI问卷得分（中间3，IQR 2）影响最大。 （中位数2，IQR 2）。假TBS和真实RHI状况在患者的电感知测试中也显示出最佳结果（中值1.9 mA）。相反，通过TBS对S1皮质兴奋性的上调似乎削弱了RHI的作用。这可能是由于中枢神经系统和周围神经之间的自上而下的连接加强，从而降低了RHI。这一发现有助于理解健康受试者和脊髓损伤患者自上而下和自下而上的机制。RHI范式可能代表了一种改善触感的有趣治疗方法，而rTMS技术可以调节这些效果。然而，还需要进一步的研究，以检查TMS和RH相互作用的方向。