PDF(Pubmed)
Abstract：
Brown-Séquard Syndrome (BSS) is a rare neurological condition caused by a unilateral spinal cord injury (SCI). Upon initial ipsilesional hemiplegia, patients with BSS typically show substantial functional recovery over time. Preclinical studies on experimental BSS demonstrated that spontaneous neuroplasticity in descending motor systems is a key mechanism promoting functional recovery. The reticulospinal (RS) system is one of the main descending motor systems showing a remarkably high ability for neuroplastic adaptations after incomplete SCI. In humans, little is known about the contribution of RS plasticity to functional restoration after SCI. Here, we investigated RS motor drive to different muscles in a subject with Brown-Séquard-plus Syndrome (BSPS) five months post-injury using the StartReact paradigm. RS drive was compared between ipsi- and contralesional muscles, and associated with measures of functional recovery. Additionally, corticospinal (CS) drive was investigated using transcranial magnetic stimulation (TMS) in a subset of muscles. The biceps brachii showed a substantial enhancement of RS drive on the ipsi- vs. contralesional side, whereas no signs of CS plasticity were found ipsilesionally. This finding implies that motor recovery of ipsilesional elbow flexion is primarily driven by the RS system. Results were inversed for the ipsilesional tibialis anterior, where RS drive was not augmented, but motor-evoked potentials recovered over six months post-injury, suggesting that CS plasticity contributed to improvements in ankle dorsiflexion. Our findings indicate that the role of RS and CS plasticity in motor recovery differs between muscles, with CS plasticity being essential for the restoration of distal extremity motor function, and RS plasticity being important for the functional recovery of proximal flexor muscles after SCI in humans.
摘要：
Brown-Séquard综合征（BSS）是由单侧脊髓损伤（SCI）引起的罕见神经系统疾病。初次同损偏瘫时，BSS患者通常随着时间的推移表现出实质性的功能恢复。对实验性BSS的临床前研究表明，下降运动系统中的自发神经可塑性是促进功能恢复的关键机制。网状脊髓（RS）系统是主要的下降运动系统之一，在不完全SCI后表现出非常高的神经可塑性适应能力。在人类中,关于RS可塑性对SCI后功能恢复的贡献知之甚少。这里,我们使用StartReact范式研究了受伤后5个月布朗-Séquard综合征（BSPS）患者对不同肌肉的RS运动驱动。比较了纵隔肌和对比肌的RS驱动，并与功能恢复措施相关。此外,使用经颅磁刺激（TMS）对一部分肌肉进行了皮质脊髓（CS）驱动研究。肱二头肌在ipsi-vs.对比侧，而同时没有发现CS可塑性的迹象。这一发现表明，同时肘关节屈曲的运动恢复主要由RS系统驱动。胫骨前肌的结果倒置，RS驱动器没有增强，但是运动诱发电位在受伤后六个月内恢复了，表明CS可塑性有助于改善踝关节背屈。我们的发现表明，RS和CS可塑性在运动恢复中的作用在肌肉之间不同，CS可塑性对于恢复远端肢体运动功能至关重要，RS可塑性对于人类SCI后近端屈肌的功能恢复很重要。
