Paparella Ivana, Leodori Giorgio, Belvisi Daniele, Koch Giacomo, Conte Antonella, Spampinato Danny Adrian
Department of Human Neuroscience, Sapienza University of Rome, Viale dell'Università, Rome, Italy.
Department of Neuroscience and Rehabilitation, Section of Physiology, University of Ferrara, Ferrara, Italy.
J Neurophysiol. 2025 Aug 1;134(2):610-618. doi: 10.1152/jn.00596.2024. Epub 2025 Jul 21.
The cerebellum plays a crucial role in motor learning, facilitating processes such as timing, error correction, and coordination. However, optimizing noninvasive brain stimulation (NIBS) to enhance these processes remains challenging. This study investigated the effects of cerebellar transcranial alternating current stimulation (tACS) at 5 Hz and 50 Hz on motor learning during a serial reaction time task (SRTT). Twenty-six healthy participants completed three sessions, receiving 5 Hz, 50 Hz, or Sham stimulation during SRTT performance. Changes in reaction time and sequence performance were measured during the online stimulation phase, with motor retention assessed 24 h later. We found that 5 Hz tACS significantly improved motor performance during the early stages of sequence learning, as demonstrated by faster reaction times compared to the 50 Hz and Sham conditions. These effects, specific to early acquisition phases, align with the cerebellum's involvement in motor timing and error correction. No significant improvements were observed during offline motor retention, possibly due to the weaker entrainment or lack of prolonged sessions required for long-term plasticity. Furthermore, 50 Hz tACS did not influence SRTT performance, highlighting the frequency-specific nature of tACS-induced modulation. These findings suggest that theta-frequency tACS can selectively enhance cerebellar contributions to motor learning by aligning stimulation with intrinsic oscillations. Although transient, theta-tACS shows promise for modulating motor circuits in both research and clinical contexts. Future studies should investigate theta-tACS in more complex tasks and explore its therapeutic potential for sustained motor rehabilitation outcomes. This study highlights the potential of 5-Hz theta-frequency cerebellar transcranial alternating current stimulation (tACS) to enhance early motor learning. During a serial reaction time task, 5-Hz tACS significantly improved reaction times compared with 50 Hz and Sham conditions, aligning with the cerebellum's role in motor timing and error correction. Though effects were transient, these findings underscore the frequency-specific benefits of tACS and its promise for advancing motor learning research and therapeutic applications.
小脑在运动学习中起着关键作用，促进诸如时间控制、错误纠正和协调等过程。然而，优化非侵入性脑刺激（NIBS）以增强这些过程仍然具有挑战性。本研究调查了5赫兹和50赫兹的小脑经颅交流电刺激（tACS）在序列反应时任务（SRTT）期间对运动学习的影响。26名健康参与者完成了三个阶段，在SRTT执行期间接受5赫兹、50赫兹或假刺激。在在线刺激阶段测量反应时间和序列表现的变化，并在24小时后评估运动记忆。我们发现，与50赫兹和假刺激条件相比，5赫兹tACS在序列学习的早期阶段显著提高了运动表现，反应时间更快。这些特定于早期习得阶段的效应与小脑在运动时间控制和错误纠正中的作用一致。在离线运动记忆期间未观察到显著改善，可能是由于较弱的同步或缺乏长期可塑性所需的延长疗程。此外，50赫兹tACS对SRTT表现没有影响，突出了tACS诱导调制的频率特异性。这些发现表明，θ频率tACS可以通过使刺激与内在振荡同步来选择性增强小脑对运动学习的贡献。尽管是短暂的，θ-tACS在研究和临床环境中调节运动回路方面显示出前景。未来的研究应在更复杂的任务中研究θ-tACS，并探索其对持续运动康复结果的治疗潜力。本研究强调了5赫兹θ频率小脑经颅交流电刺激（tACS）增强早期运动学习的潜力。在序列反应时任务期间，与50赫兹和假刺激条件相比，5赫兹tACS显著改善了反应时间，这与小脑在运动时间控制和错误纠正中的作用一致。尽管效应是短暂的，但这些发现强调了tACS的频率特异性益处及其在推进运动学习研究和治疗应用方面的前景。
