Altered excitability of motor neuron pathways after stroke: more than upper motor neuron impairments

Stroke and Vascular Neurology

article

Pingping Li¹  Chunyong Chen¹  Baozi Huang¹  Zimu Jiang¹  Jiating Wei¹  Jinsheng Zeng¹ 

[1] Department of Neurology and Stroke Center, National Key Clinical Department and Key Discipline of Neurology , The First Affiliated Hospital, Sun Yat-sen University;Department of Neurology , The First Affiliated Hospital of Guangxi Medical University

关键词: stroke;    cerebral infarction;    cerebrovascular disorders;    spinal cord;   

DOI  :  10.1136/svn-2022-001568

学科分类：社会科学、人文和艺术（综合）

来源: BMJ Publishing Group

【 摘 要 】

Background Previous studies have suggested that impairment occurs in the lower motor neuron (LMN) pathway after stroke, but more research remains to be supported.Objective In this study, we tested the hypotheses: (1) both motor cortex and peripheral nerve pathways have decreased excitability and structural damage after stroke; (2) parameters of transcranial magnetic stimulation motor evoked potentials (TMS-MEP) can be used as predictors of motor function and stroke prognosis.Methods We studied five male cynomolgus monkeys with ischaemic stroke. TMS-MEP, cranial MRI, behavioural assessment, neurological scales and pathology were applied.Results Elevated resting motor threshold (RMT) (p<0.05), decreased TMS-MEP amplitudes (p<0.05) and negative RMT lateralisation were detected in both the affected motor cortex (AMC) and the paretic side median nerve (PMN) at 2 weeks poststroke. Disturbed structure and loose arrangement of myelin sheaths were observed in the PMN through H&E staining and LFB staining at 12 weeks poststroke. The primate Rankin Scale (used for assess the stroke prognosis) scores at 2–12 weeks after middle cerebral artery occlusion were [1, (1; 3)], [1, (1;2)], [1, (1; 1.5)] and [1, (1; 1.5)], respectively. The RMT and RMT lateralisation (AMC) were predictors of stroke prognosis, and the RMT lateralisation of PMN and latency of AMC were predictors of motor impairment.Conclusions Both upper motor neuron (UMN) and LMN pathway excitability is reduced after stroke, and structural damage in median nerve 12 weeks after stroke occur. In addition, RMT and RMT lateralisation are predictors of stroke prognosis and motor impairment.

【 授权许可】

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