Department of Psychiatry and Psychotherapy, Medical Center, University of Freiburg-Faculty of Medicine, University of Freiburg, Hauptstrasse 5, 79104, Freiburg, Germany.
Faculty of Science and Engineering, BCN Research Master (C-Tracks), s375081, University of Groningen, Groningen, The Netherlands.
J Neuroeng Rehabil. 2024 Sep 18;21(1):162. doi: 10.1186/s12984-024-01459-x.
Transcranial direct current stimulation (tDCS) is capable of eliciting changes in cortical neuroplasticity. Increasing duration or repetition of tDCS during the after-effects of a first stimulation has been hypothesized to enhance efficacy. Computational models suggest sequential stimulation patterns with changing polarities to further enhance effects. Lasting tDCS effects on neural plasticity are of great importance for clinical applications.
The study systematically examined the influence of different tDCS paradigms on long term potentiation (LTP)-like plasticity in humans, focusing on stimulation duration, repetition frequency and sequential combinations of changing polarities as the underlying characteristics.
Amplitude changes of motor evoked potentials (MEP) were measured in response to paired associative stimulation (PAS) 6 h after application of different tDCS protocols. In total, 36 healthy participants completed the study, randomised into three groups with different stimulation protocols (N = 12 each).
tDCS was able to display lasting modulatory effects on the inducibility of LTP-like plasticity in the human motor cortex 6 h after stimulation. TDCS with the anode on primary motor cortex significantly increased MEP amplitudes following PAS induction. Further analyses highlighted single stimulation block duration to be of higher importance than repetitive protocols for efficacy of effects.
tDCS is capable of inducing lasting changes in the brain's capability to interact with future stimuli. Especially, effects on the inducibility of LTP-like plasticity might only be detectable with specific tests such as PAS and might otherwise be overlooked. Refined tDCS protocols should focus on higher current and duration of single stimulations instead of implementing complex repetitive schedules.
经颅直流电刺激（tDCS）能够引起皮质神经可塑性的变化。在第一次刺激的后效期间增加 tDCS 的持续时间或重复次数，被假设可以增强疗效。计算模型表明，采用改变极性的顺序刺激模式可以进一步增强效果。tDCS 对神经可塑性的持久影响对于临床应用非常重要。
本研究系统地检查了不同 tDCS 范式对人类长时程增强（LTP）样可塑性的影响，重点研究了刺激持续时间、重复频率和改变极性的顺序组合作为潜在特征。
在应用不同的 tDCS 方案 6 小时后，通过成对关联刺激（PAS）测量运动诱发电位（MEP）的幅度变化。共有 36 名健康参与者完成了这项研究，随机分为三组，每组接受不同的刺激方案（每组 12 人）。
tDCS 能够在刺激后 6 小时对人类运动皮层的 LTP 样可塑性的诱导产生持久的调节作用。阳极置于初级运动皮层的 tDCS 可显著增加 PAS 诱导后的 MEP 幅度。进一步的分析强调了单个刺激块的持续时间比重复方案对效果的重要性更高。
tDCS 能够诱导大脑与未来刺激相互作用的能力发生持久变化。特别是，LTP 样可塑性的诱导能力只有通过 PAS 等特定测试才能检测到，否则可能会被忽视。改进的 tDCS 方案应侧重于更高的电流和单个刺激的持续时间，而不是实施复杂的重复方案。
