Neck rotation modulates flexion synergy torques, indicating an ipsilateral reticulospinal source for impairment in stroke
Neck rotation modulates flexion synergy torques, indicating an ipsilateral reticulospinal source for impairment in stroke
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DOI：
10.1152/jn.01030.2011
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发表时间：
2012-12-01
影响因子：
2.5
通讯作者：
Dewald, Julius P. A.
中科院分区：
文献类型：
--
作者：
Ellis, Michael D.;Drogos, Justin;Dewald, Julius P. A.
Ellis MD，Drogos J，Carmona C，Keller T，Dewald JP.颈部旋转调节屈曲协同扭矩，表明中风损伤的同侧网状脊髓来源。J Neurophysiol 108：3096-3104，2012.首次发表于2012年9月5日; doi：10.1152/jn.01030.2011.-在26名中风患者和9名年龄范围匹配的对照者中，通过自然诱发（主动头部旋转）不对称强直性颈反射（ATNR），研究了网状结构兴奋性对最大随意扭矩（MVT）产生和相关肩肘肌肉激活的影响。通过旋转头部量化肩部和肘部的等距MVT生成（面部指向）对侧和同侧的麻痹（中风）和优势（控制）手臂。鉴于肘关节屈曲与肩关节外展的异常扭矩耦合的优势，（屈曲协同作用）在中风和发育良好的动物模型中证明了网状结构与同侧肘屈肌和肩外展肌之间的联系，我们假设屈曲协同作用的组成扭矩，特别是肘关节屈曲和肩关节外展，将随着对侧头部旋转而增加。调查结果支持这一假设。在对侧头部旋转过程中，仅在中风患者中观察到四种屈曲协同成分中的三种（肘关节屈曲、肩关节外展和肩关节外旋）的MVT增加。相关肌肉共激活的肌电图数据无显著性，但鉴于该特定变量的统计设计可能不足，因此将其列出以供考虑。这项研究不仅为中风后ATNR的重新出现提供了证据，而且还表明了一个共同的神经解剖学联系，即对同侧网状脊髓通路的依赖性增加，这可能是导致独立关节控制丧失的ATNR和屈曲协同作用表达的潜在机制。
Ellis MD, Drogos J, Carmona C, Keller T, Dewald JP. Neck rotation modulates flexion synergy torques, indicating an ipsilateral reticulospinal source for impairment in stroke. J Neurophysiol 108: 3096-3104, 2012. First published September 5, 2012; doi: 10.1152/jn.01030.2011.-The effect of reticular formation excitability on maximum voluntary torque (MVT) generation and associated muscle activation at the shoulder and elbow was investigated through natural elicitation (active head rotation) of the asymmetric tonic neck reflex (ATNR) in 26 individuals with stroke and 9 age-range-matched controls. Isometric MVT generation at the shoulder and elbow was quantified with the head rotated (face pointing) contralateral and ipsilateral to the paretic (stroke) and dominant (control) arm. Given the dominance of abnormal torque coupling of elbow flexion with shoulder abduction (flexion synergy) in stroke and well-developed animal models demonstrating a linkage between reticular formation and ipsilateral elbow flexors and shoulder abductors, we hypothesized that constituent torques of flexion synergy, specifically elbow flexion and shoulder abduction, would increase with contralateral head rotation. The findings of this investigation support this hypothesis. Increases in MVT for three of four flexion synergy constituents (elbow flexion, shoulder abduction, and shoulder external rotation) were observed during contralateral head rotation only in individuals with stroke. Electromyographic data of the associated muscle coactivations were nonsignificant but are presented for consideration in light of a likely underpowered statistical design for this specific variable. This study not only provides evidence for the reemergence of ATNR following stroke but also indicates a common neuroanatomical link, namely, an increased reliance on ipsilateral reticulospinal pathways, as the likely mechanism underlying the expression of both ATNR and flexion synergy that results in the loss of independent joint control.