EEG data MiEEG data Mirror Visual Feedback with electrical painful and non-painful stimulationsrror Visual Feedback with electrical painful and non-painful stimulations

Experimental procedure:The participants were comfortably seated on a chair with their arms lying symmetrically ahead on a table. Auditory cues of 70 dB, 1000 Hz, and 50 ms of duration (Kida et al., 2006) were used to trigger right index finger movements. All the subjects underwent three different conditions (80 trials each) in randomized order. Each condition lasted approx. 13 min with 10 min breaks between the conditions. The whole session – including EEG net preparation, training, pain threshold measurement, and experiment – lasted approx. 2.5 hours. In the experimental condition (Unilateral with Mirror, or UM+), the mirror was placed on the desk, perpendicularly to the subjects’ midsagittal plane with the reflecting face on the right side (Figure 1). Subjects were instructed to move the right index finger in response to the auditory cue while watching the image of the reflected moving hand in the mirror to give the illusion of the simultaneous left index finger movement. The position of the left hand behind the mirror corresponded to the image of the left hand reflected in the mirror. In the control conditions, the mirror was removed from the experimental setting and the left hand was directly visible to the participants. In one control condition (Unilateral without Mirror, UM-), subjects were asked to perform the same unilateral right index finger movements. In the other control condition (Bilateral without Mirror, BM-), subjects had to perform synchronous movements of both index fingers. The movements consisted of a double extension of the index finger with a slow release toward the bottom (approx. 1 s). All the participants received a brief training to perform the movement correctly and keep the left hand as still as possible during the unilateral conditions. In each condition, an electrical stimulus was delivered on the tip of the left index finger 100 ms after the auditory cue to induce cortical sensory-motor interaction (Figure 2). The interval between the stimuli was fixed at 10 s, a sufficient period to reset the desynchronization of the alpha rhythms (Babiloni et al., 2008). A fixed interval also allowed to produce a sort of predictability of the upcoming auditory and electrical stimuli, optimal to study the anticipatory alpha ERD/ERS responses. However, subjects were not informed of this fixed interval to avoid any counting strategies.EEG data are uploaded in .hdf5 extension (g.recorder amplifier) to be analyzed with EEGLAB toolbox for MATLAB.Raw data coding slightly differs from the one presented in the original manuscript:no-M+P = UM-no-M+P-bil = BM-yes-M+P = UM+实验流程：受试者舒适地坐在椅子上，双臂对称前伸置于桌面。采用70 dB、1000 Hz、时长50 ms的听觉提示（auditory cue，Kida等，2006）触发右侧食指运动。所有受试者均以随机顺序完成三种不同实验条件（每种条件含80个试次）。每个实验条件持续约13分钟，条件间休息10分钟。整个实验流程——包括脑电帽（EEG net）准备、训练、痛阈测量与正式实验——总时长约2.5小时。实验条件（单侧带镜像，Unilateral with Mirror，简称UM+）中，镜子置于桌面，与受试者的正中矢状面（midsagittal plane）垂直，镜面朝向右侧（图1）。受试者被要求根据听觉提示移动右侧食指，同时观察镜中移动手部的反射影像，以产生左侧食指同步运动的视觉错觉。镜子后方的左手位置与镜中反射的左手影像相对应。在对照条件中，移除实验装置内的镜子，受试者可直接看到左手。其中一种对照条件（单侧不带镜像，Unilateral without Mirror，简称UM-）中，受试者被要求完成相同的单侧右侧食指运动；另一对照条件（双侧不带镜像，Bilateral without Mirror，简称BM-）中，受试者需完成双侧食指的同步运动。该运动为食指两次伸展，随后缓慢向下放松（总时长约1秒）。所有受试者均接受简短训练，以正确完成该运动，并在单侧条件下尽可能保持左手静止。每个条件中，在听觉提示发出100 ms后，于左手食指指尖施加电刺激，以诱发皮层感觉运动交互作用（图2）。刺激间隔固定为10秒，该时长足以重置α节律（alpha rhythms）的去同步化状态（Babiloni等，2008）。固定间隔还可使受试者对即将到来的听觉与电刺激产生一定可预测性，这为研究预期性α事件相关去同步/同步（alpha ERD/ERS）响应提供了最优条件。但受试者并未被告知该固定间隔，以避免其采用计数策略。脑电数据以.hdf5格式上传（配套g.recorder放大器），可使用MATLAB的EEGLAB工具箱进行分析。原始数据编码与原手稿中的略有差异：no-M+P = UM-；no-M+P-bil = BM-；yes-M+P = UM+