Background. Stroke often involves primary motor cortex (M1) and its corticospinal (CST) projections. As hand function is critically dependent on these structures, its recovery is often incomplete. Objective. To determine whether impaired hand function in patients with chronic ischemic stroke involving M1 or CST benefits from the enhancing effect of Hebbian-type stimulation (pairing M1 afferent stimulation and M1 activity in a specific temporal relationship) on M1 plasticity and hand function. Methods. In a double-blind, randomized, sham-controlled design, 20 patients with chronic ischemic stroke affecting M1 or CST were randomly assigned to 5 days of hand motor training that was combined with either Hebbian-type (trainingHebb) or sham stimulation (trainingsham) of the lesioned M1. Measures of hand function and task-based M1 functional magnetic resonance imaging (fMRI) activity were collected prior to, immediately following, and 4 weeks after the intervention. Results. Both interventions were effective in improving affected hand function at the completion of training, but only participants in the trainingHebb group maintained functional gains. Changes in hand function and fMRI activity were positively correlated in both ipsilesional and contralesional M1. Compared with trainingsham, participants in the trainingHebb group showed a stronger relationship between improved hand function and changes in M1 functional activity. Conclusions. Only when motor training was combined with Hebbian-type stimulation were functional gains maintained over time and correlated with measures of M1 functional plasticity. As hand dexterity is critically dependent on M1 function, these results suggest that functional reorganization in M1 is facilitated by Hebbian-type stimulation. ClinicalTrials.gov Identifier: NCT01569607.

中文翻译：

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Hebbian 型初级运动皮层刺激：慢性中风患者手功能受损的潜在治疗

背景。中风通常涉及初级运动皮层 (M1) 及其皮质脊髓 (CST) 投射。由于手部功能严重依赖于这些结构，因此其恢复通常不完整。客观的。确定涉及 M1 或 CST 的慢性缺血性卒中患者的手功能受损是否受益于 Hebbian 型刺激（在特定时间关系中配对 M1 传入刺激和 M1 活动）对 M1 可塑性和手功能的增强作用。方法。在一项双盲、随机、假手术对照设计中，20 名患有 M1 或 CST 的慢性缺血性卒中患者被随机分配接受 5 天的手部运动训练，并结合 Hebbian 型 (trainingHebb) 或假刺激 (trainingsham)受损的 M1。在干预前、干预后立即和干预后 4 周收集手功能和基于任务的 M1 功能磁共振成像 (fMRI) 活动的测量值。结果。两种干预措施均能有效改善训练结束时受影响的手部功能，但只有训练 Hebb 组的参与者才能保持功能增益。手功能和 fMRI 活动的变化在同侧和对侧 M1 中均呈正相关。与trainingsham相比，trainingHebb组的参与者表现出手部功能改善与M1功能活动变化之间的关系更强。结论。只有当运动训练与赫布式刺激相结合时，功能增益才会随着时间的推移而保持，并与 M1 功能可塑性的测量相关。由于手的灵活性严重依赖于 M1 的功能，这些结果表明赫布型刺激促进了 M1 的功能重组。ClinicalTrials.gov 标识符：NCT01569607。