Spasticity and motor recovery are both related to neural plasticity after stroke. A balance of activity in the primary motor cortex (M1) in both hemispheres is essential for functional recovery. In this study, we assessed the intracortical inhibitory and facilitatory circuits in the contralesional M1 area in four patients with severe upper limb spasticity after chronic stroke and treated with botulinum toxin-A (BoNT-A) injection and 12 weeks of upper limb rehabilitation. There was little to no change in the level of spasticity post-injection, and only one participant experienced a small improvement in arm function. All reported improvements in quality of life. However, the levels of intracortical inhibition and facilitation in the contralesional hemisphere were different at baseline for all four participants, and there was no clear pattern in the response to the intervention. Further investigation is needed to understand how BoNT-A injections affect inhibitory and facilitatory circuits in the contralesional hemisphere, the severity of spasticity, and functional improvement.

中文翻译：

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A 型肉毒杆菌毒素注射后慢性中风患者对侧初级运动皮层的皮质内回路：案例研究

痉挛和运动恢复都与中风后的神经可塑性有关。两个半球的初级运动皮层 (M1) 的活动平衡对于功能恢复至关重要。在这项研究中，我们评估了 4 名慢性卒中后严重上肢痉挛并接受肉毒杆菌毒素-A (BoNT-A) 注射和 12 周上肢康复治疗的患者对侧 M1 区的皮质内抑制和促进回路。注射后痉挛程度几乎没有变化，只有一名参与者的手臂功能略有改善。所有人都报告了生活质量的改善。然而，所有四名参与者在基线时对侧半球的皮质内抑制和促进水平不同，对干预的反应没有明确的模式。需要进一步研究以了解 BoNT-A 注射如何影响对侧半球的抑制和促进回路、痉挛的严重程度和功能改善。