Transcranial direct current stimulation (tDCS) is a non-invasive tool for inducing cortical excitability changes [1]. Numerous studies have investigated the effects of tDCS over the primary motor cortex (M1) for exploring mechanisms underlying cortical plasticity and motor functions of the limbs. However, little is known about the effects of tDCS on the tongue region. Here, we investigated the effects of anodal tDCS over the bilateral tongue M1 representation relative to those of unilateral anodal tDCS on tongue region cortical excitability and tongue and jaw motor functions. Fifteen healthy volunteers (11 men; mean age, 24.5 years) participated in this randomized, double-blind, sham-controlled, crossover study. Participants provided written informed consent; procedures were approved by the local ethics committee. Three sessions of either anodal tDCS over both hemispheres (bi-tDCS), anodal tDCS over the left hemisphere (lt-tDCS), or sham stimulation were performed with an inter-session interval of at least 7 days for each subject. tDCS was applied for 20 min with a StarStim stimulator (Neuroelectrics, Barcelona, Spain) using two 24-cm2 target electrodes and one 72-cm2 return electrode. Target electrodeswere placed over the tonguemuscle “hotspot” region; return electrode was placed over the forehead. Bi-tDCS session current intensity was 2 mA (0.0833 mA/cm2) and 4 mA for the target and

中文翻译：

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双侧经颅直流电刺激舌初级运动皮层对舌皮层兴奋性及舌运动功能的影响

经颅直流电刺激 (tDCS) 是一种诱导皮质兴奋性变化的非侵入性工具 [1]。许多研究调查了 tDCS 对初级运动皮层 (M1) 的影响，以探索皮层可塑性和四肢运动功能的潜在机制。然而，关于 tDCS 对舌头区域的影响知之甚少。在这里，我们研究了阳极 tDCS 对双侧舌头 M1 表示相对于单侧阳极 tDCS 对舌头区域皮质兴奋性和舌头和下巴运动功能的影响。15 名健康志愿者（11 名男性；平均年龄 24.5 岁）参与了这项随机、双盲、假对照、交叉研究。参与者提供了书面知情同意书；程序经当地伦理委员会批准。对每个受试者进行至少 7 天的会话间间隔，在两个半球 (bi-tDCS) 上的阳极 tDCS、左半球上的阳极 tDCS (lt-tDCS) 或假刺激的三个会话。使用两个 24-cm2 目标电极和一个 72-cm2 返回电极，使用 StarStim 刺激器（Neuroelectrics，Barcelona，Spain）施加 tDCS 20 分钟。目标电极放置在舌肌“热点”区域；返回电极放置在前额上。Bi-tDCS 会话电流强度为 2 mA (0.0833 mA/cm2) 和 4 mA 对于目标和 西班牙）使用两个 24-cm2 靶电极和一个 72-cm2 返回电极。目标电极放置在舌肌“热点”区域；返回电极放置在前额上。Bi-tDCS 会话电流强度为 2 mA (0.0833 mA/cm2) 和 4 mA 对于目标和 西班牙）使用两个 24-cm2 靶电极和一个 72-cm2 返回电极。目标电极放置在舌肌“热点”区域；返回电极放置在前额上。Bi-tDCS 会话电流强度为 2 mA (0.0833 mA/cm2) 和 4 mA 对于目标和