Rroji Orjon, van Kuyck Kris, Nuttin Bart, Wenderoth Nicole
Department of Kinesiology, Research Center for Movement Control and Neuroplasticity, KU Leuven, Leuven, Belgium.
Department of Neurosciences, Research Group Experimental Neurosurgery and Neuroanatomy, KU Leuven, Leuven, Belgium.
PLoS One. 2015 May 21;10(5):e0127270. doi: 10.1371/journal.pone.0127270. eCollection 2015.
Previous research suggests that anodal transcranial direct current stimulation (tDCS) over the primary motor cortex (M1) modulates NMDA receptor dependent processes that mediate synaptic plasticity. Here we test this proposal by applying anodal versus sham tDCS while subjects practiced to flex the thumb as fast as possible (ballistic movements). Repetitive practice of this task has been shown to result in performance improvements that reflect use-dependent plasticity resulting from NMDA receptor mediated, long-term potentiation (LTP)-like processes. Using a double-blind within-subject cross-over design, subjects (n=14) participated either in an anodal or a sham tDCS session which were at least 3 months apart. Sham or anodal tDCS (1 mA) was applied for 20 min during motor practice and retention was tested 30 min, 24 hours and one week later. All subjects improved performance during each of the two sessions (p < 0.001) and learning gains were similar. Our main result is that long term retention performance (i.e. 1 week after practice) was significantly better when practice was performed with anodal tDCS than with sham tDCS (p < 0.001). This effect was large (Cohen's d=1.01) and all but one subject followed the group trend. Our data strongly suggest that anodal tDCS facilitates long-term memory formation reflecting use-dependent plasticity. Our results support the notion that anodal tDCS facilitates synaptic plasticity mediated by an LTP-like mechanism, which is in accordance with previous research.
先前的研究表明，对初级运动皮层（M1）进行阳极经颅直流电刺激（tDCS）可调节介导突触可塑性的N-甲基-D-天冬氨酸（NMDA）受体依赖性过程。在此，我们通过应用阳极tDCS和伪刺激tDCS来检验这一假设，同时让受试者练习尽可能快地弯曲拇指（弹道运动）。已证明重复进行此任务可提高表现，这反映了由NMDA受体介导的、类似长时程增强（LTP）过程所导致的使用依赖性可塑性。采用双盲受试者内交叉设计，受试者（n = 14）分别参与阳极或伪刺激tDCS实验，两次实验间隔至少3个月。在运动练习期间施加伪刺激或阳极tDCS（1 mA）20分钟，并在30分钟、24小时和1周后测试记忆保持情况。所有受试者在两次实验中的表现均有改善（p < 0.001），且学习收获相似。我们的主要结果是，与伪刺激tDCS相比，在阳极tDCS下进行练习时，长期记忆保持表现（即练习后1周）显著更好（p < 0.001）。这种效应很大（科恩d值 = 1.01），除一名受试者外，所有受试者均符合组内趋势。我们的数据有力地表明，阳极tDCS促进了反映使用依赖性可塑性的长期记忆形成。我们的结果支持了阳极tDCS促进由类似LTP机制介导的突触可塑性这一观点，这与先前的研究一致。
