Inukai Yasuto, Saito Kei, Sasaki Ryoki, Kotan Shinichi, Nakagawa Masaki, Onishi Hideaki
Department of Physical Therapy, Niigata University of Health and WelfareNiigata, Japan; Institute for Human Movement and Medical Sciences, Niigata University of Health and WelfareNiigata, Japan.
Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare Niigata, Japan.
Front Hum Neurosci. 2016 Jul 7;10:325. doi: 10.3389/fnhum.2016.00325. eCollection 2016.
Damage to the vestibular cerebellum results in dysfunctional standing posture control. Patients with cerebellum dysfunction have a larger sway in the center of gravity while standing compared with healthy subjects. Transcranial direct current stimulation (tDCS) is a noninvasive technique for selectively exciting or inhibiting specific neural structures with potential applications in functional assessment and treatment of neural disorders. However, the specific stimulation parameters for influencing postural control have not been assessed. In this study, we investigated the influence of tDCS when applied over the cerebellum on standing posture control. Sixteen healthy subjects received tDCS (20 min, 2 mA) over the scalp 2 cm below the inion. In Experiment 1, all 16 subjects received tDCS under three stimulus conditions, Sham, Cathodal, and Anodal, in a random order with the second electrode placed on the forehead. In Experiment 2, five subjects received cathodal stimulation only with the second electrode placed over the right buccinator muscle. Center of gravity sway was measured twice for 60 s before and after tDCS in a standing posture with eyes open and legs closed, and average total locus length, locus length per second, rectangular area, and enveloped area were calculated. In Experiment 1, total locus length and locus length per second decreased significantly after cathodal stimulation but not after anodal or sham stimulation, while no tDCS condition influenced rectangular or enveloped areas. In Experiment 2, cathodal tDCS again significantly reduced total locus length and locus length per second but not rectangular and enveloped areas. The effects of tDCS on postural control are polarity-dependent, likely reflecting the selective excitation or inhibition of cerebellar Purkinje cells. Cathodal tDCS to the cerebellum of healthy subjects can alter body sway (velocity).
前庭小脑受损会导致站立姿势控制功能障碍。与健康受试者相比，小脑功能障碍患者站立时重心摆动更大。经颅直流电刺激（tDCS）是一种非侵入性技术，可选择性地兴奋或抑制特定神经结构，在神经疾病的功能评估和治疗中具有潜在应用价值。然而，影响姿势控制的具体刺激参数尚未得到评估。在本研究中，我们调查了将tDCS应用于小脑对站立姿势控制的影响。16名健康受试者在枕外隆凸下方2厘米处的头皮上接受tDCS（20分钟，2毫安）。在实验1中，所有16名受试者在三种刺激条件下接受tDCS，即假刺激、阴极刺激和阳极刺激，顺序随机，第二个电极置于前额。在实验2中，五名受试者仅接受阴极刺激，第二个电极置于右侧颊肌上方。在睁眼并双腿并拢站立姿势下，于tDCS前后各测量60秒的重心摆动两次，并计算平均总轨迹长度、每秒轨迹长度、矩形面积和包络面积。在实验1中，阴极刺激后总轨迹长度和每秒轨迹长度显著降低，而阳极或假刺激后则未降低，同时没有tDCS条件影响矩形或包络面积。在实验2中，阴极tDCS再次显著降低了总轨迹长度和每秒轨迹长度，但未影响矩形和包络面积。tDCS对姿势控制的影响取决于极性，可能反映了小脑浦肯野细胞的选择性兴奋或抑制。对健康受试者的小脑进行阴极tDCS可改变身体摆动（速度）。
