Table_1_Effects of online and offline trigeminal nerve stimulation on visuomotor learning.docx

IntroductionA current thrust in neurology involves using exogenous neuromodulation of cranial nerves (e.g, vagus, trigeminal) to treat the signs and symptoms of various neurological disorders. These techniques also have the potential to augment cognitive and/or sensorimotor functions in healthy individuals. Although much is known about the clinical effects of trigeminal nerve stimulation (TNS), effects on sensorimotor and cognitive functions such as learning have received less attention, despite their potential impact on neurorehabilitation. Here we describe the results of experiments aimed at assessing the effects of TNS on motor learning, which was behaviorally characterized using an upper extremity visuomotor adaptation paradigm.ObjectiveAssessing the effects of TNS on motor learning.MethodsMotor learning was behaviorally characterized using an upper extremity visuomotor adaptation paradigm. In Experiment 1, effects of offline TNS using clinically tested frequencies (120 and 60 Hz) were characterized. Sixty-three healthy young adults received TNS before performing a task that involved reaching with perturbed hand visual feedback. In Experiment 2, the effects of 120 and 60 Hz online TNS were characterized with the same task. Sixty-three new participants received either TNS or sham stimulation concurrently with perturbed visual feedback.ResultsExperiment 1 results showed that 60 Hz stimulation was associated with slower rates of learning than both sham and 120 Hz stimulation, indicating frequency-dependent effects of TNS. Experiment 2 however showed no significant differences among stimulation groups. A post-hoc, cross-study comparison of the 60 Hz offline and online TNS results showed a statistically significant improvement in learning rates with online stimulation relative to offline, pointing to timing-dependent effects of TNS on visuomotor learning.DiscussionThe results indicate that both the frequency and timing of TNS can influence rates of motor learning in healthy adults. This suggests that optimization of one or both parameters could potentially increase learning rates, which would provide new avenues for enhancing performance in healthy individuals and augmenting rehabilitation in patients with sensorimotor dysfunction resulting from stroke or other neurological disorders.

当前神经学领域的研究热点之一是利用颅神经（如迷走神经、三叉神经）的外源性神经调节来治疗各种神经疾病的症状和体征。这些技术同样具有增强健康个体认知和/或感觉运动功能的能力。尽管关于三叉神经刺激（TNS）的临床效应已广为人知，但对其在感觉运动和认知功能，如学习方面的影响却关注不足，尽管这些影响对神经康复具有潜在的重要性。在本研究中，我们描述了旨在评估TNS对运动学习影响实验的结果，运动学习的行为特征通过上肢视觉运动适应范式进行表征。研究目标评估TNS对运动学习的影响。研究方法采用上肢视觉运动适应范式对运动学习进行行为表征。在实验1中，使用临床验证的频率（120Hz和60Hz）进行了离线TNS效应的特征化。63名健康青年成年人在执行涉及受损手视觉反馈的伸手任务前接受了TNS。在实验2中，使用相同的任务对120Hz和60Hz的在线TNS效应进行了特征化。63名新的参与者在接受受损视觉反馈的同时接受了TNS或假刺激。研究结果实验1的结果表明，60Hz的刺激与假刺激和120Hz刺激相比，学习速率较慢，表明TNS的频率依赖性效应。然而，实验2显示刺激组之间没有显著差异。对60Hz离线和在线TNS结果的后设分析，与离线刺激相比，在线刺激显示出统计学上显著的学习速率提高，这表明TNS对视觉运动学习的影响具有时间依赖性。讨论结果表明，TNS的频率和时间都可以影响健康成年人的运动学习速率。这表明，优化一个或两个参数可能有助于提高学习速率，从而为增强健康个体的表现和增强因中风或其他神经疾病引起的感觉运动功能障碍患者的康复提供新的途径。