Objective. Proximal-to-distal compensation is commonly observed in the upper extremity (UE) after a stroke, mainly due to the impaired fine motor control in hand joints. However, little is known about its related neural reorganization. This study investigated the pathway-specific corticomuscular interaction in proximal-to-distal UE compensation during fine motor control of finger extension post-stroke by directed corticomuscular coherence (dCMC). Approach. We recruited 14 chronic stroke participants and 11 unimpaired controls. Electroencephalogram (EEG) from the sensorimotor area was concurrently recorded with electromyography (EMG) from extensor digitorum (ED), flexor digitorum (FD), triceps brachii (TRI) and biceps brachii (BIC) muscles in both sides of the stroke participants and in the dominant (right) side of the controls during the unilateral isometric finger extension at 20% maximal voluntary contractions. The dCMC was analyzed in descending (EEG → EMG) and ascending pathways (EMG → EEG) via the directed coherence. It was also analyzed in stable (segments with higher EMG stability) and less-stable periods (segments with lower EMG stability) subdivided from the whole movement period to investigate the fine motor control. Finally, the corticomuscular conduction time was estimated by dCMC phase delay. Main results. The affected limb had significantly lower descending dCMC in distal UE (ED and FD) than BIC (P < 0.05). It showed the descending dominance (significantly higher descending dCMC than the ascending, P < 0.05) in proximal UE (BIC and TRI) rather than the distal UE as in the controls. In the less-stable period, the affected limb had significantly lower EMG stability but higher ascending dCMC (P < 0.05) in distal UE than the controls. Furthermore, significantly prolonged descending conduction time (∼38.8 ms) was found in ED in the affected limb than the unaffected (∼26.94 ms) and control limbs (∼25.74 ms) (P < 0.05). Significance. The proximal-to-distal UE compensation in fine motor control post-stroke exhibited altered descending dominance from the distal to proximal UE, increased ascending feedbacks from the distal UE for fine motor control, and prolonged descending conduction time in the agonist muscle.

客观的。中风后上肢 (UE) 通常会出现近端到远端代偿，主要是由于手关节精细运动控制受损。然而，对其相关的神经重组知之甚少。本研究通过定向皮质肌肉连贯性 (dCMC) 研究了在中风后手指伸展的精细运动控制期间，近端到远端 UE 补偿中通路特异性的皮质肌肉相互作用。方法。我们招募了 14 名慢性卒中参与者和 11 名未受损的对照组。来自感觉运动区的脑电图 (EEG) 与来自中风参与者两侧的指伸肌 (ED)、指屈肌 (FD)、肱三头肌 (TRI) 和肱二头肌 (BIC) 肌肉的肌电图 (EMG) 同时记录在 20% 最大自主收缩的单侧等距手指伸展过程中，控制的主导（右侧）侧。通过定向相干在下行（EEG → EMG）和上行通路（EMG → EEG）中分析 dCMC。还对从整个运动周期细分的稳定期（肌电图稳定性较高的段）和不稳定期（肌电图稳定性较低的段）进行了分析，以研究精细运动控制。最后，主要结果。患肢远端 UE（ED 和 FD）的降 dCMC 显着低于 BIC（P < 0.05）。它显示了近端 UE（BIC 和 TRI）的下降优势（下降 dCMC 显着高于上升，P < 0.05），而不是像对照组那样远端 UE。在不太稳定的时期，患肢的肌电图稳定性显着降低，但远端 UE 的上升 dCMC 高于对照组（P < 0.05）。此外，与未受影响的肢体（~26.94 ms）和对照肢体（~25.74 ms）相比，ED 患肢的降传导时间（~38.8 ms）显着延长（P < 0.05）。意义。 卒中后精细运动控制中从近端到远端的 UE 补偿表现出从远端到近端 UE 的下降优势改变，增加了来自远端 UE 的用于精细运动控制的上升反馈，并延长了激动肌的下行传导时间。