Eilfort Antonia Maria, Rasenack Maria, Zörner Björn, Curt Armin, Filli Linard
Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland.
Neuroscience Center Zurich, University of Zurich, Zurich, Switzerland.
Front Neurol. 2024 Jun 4;15:1335795. doi: 10.3389/fneur.2024.1335795. eCollection 2024.
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.
布朗 - 色夸综合征（Brown-Séquard Syndrome，BSS）是一种由单侧脊髓损伤（spinal cord injury，SCI）引起的罕见神经系统疾病。在最初出现同侧偏瘫后，BSS患者通常会随着时间的推移显示出显著的功能恢复。对实验性BSS的临床前研究表明，下行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（Reticulospinal，RS）系统是主要的下行运动系统之一，在不完全性SCI后表现出极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。在此，我们使用StartReact范式，对一名损伤后5个月的布朗 - 色夸加综合征（Brown-Séquard-plus Syndrome，BSPS）患者不同肌肉的RS运动驱动进行了研究。比较了同侧和对侧肌肉的RS驱动，并将其与功能恢复的指标相关联。此外，在一部分肌肉中使用经颅磁刺激（transcranial magnetic stimulation，TMS）研究了皮质脊髓（corticospinal，CS）驱动。肱二头肌在同侧与对侧相比显示出RS驱动的显著增强，而在同侧未发现CS可塑性的迹象。这一发现意味着同侧肘关节屈曲的运动恢复主要由RS系统驱动。同侧胫前肌的结果则相反，其RS驱动未增强，但运动诱发电位在损伤后6个月内恢复，表明CS可塑性有助于改善踝关节背屈。我们的研究结果表明，RS和CS可塑性在运动恢复中的作用因肌肉而异，CS可塑性对于远端肢体运动功能的恢复至关重要，而RS可塑性对于人类SCI后近端屈肌的功能恢复很重要。
