Cortical projections to spinal motoneurons: Changes with aging and amyotrophic lateral sclerosis
Cortical projections to spinal motoneurons: Changes with aging and amyotrophic lateral sclerosis
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DOI：
10.1212/wnl.46.5.1396
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发表时间：
1996-05-01
期刊：
影响因子：
9.9
通讯作者：
Stewart, H
中科院分区：
文献类型：
--
作者：
Eisen, A;EntezariTaher, M;Stewart, H
应用随机磁刺激法记录42例正常人（24 ~ 83岁）和42例肌萎缩侧索硬化（ALS）患者（37 ~ 84岁）趾总伸肌（EDC）单个运动单位放电的刺激周时间直方图（PSTH）。正常受试者有一个早期的发射概率增加发生在约20毫秒poststimulus，反映了潜在的复合兴奋性突触后电位（EPSP）引起的快速传导，下行volleys的corticomotoneuronal核心促进单个脊髓运动神经元。EPSP的振幅随年龄增长呈线性下降（r = 0.673）。我们估计，到50岁时，正常对照组中约有35%的皮质运动神经元丢失或无功能。与年龄匹配的对照组相比，大多数ALS患者的EPSP降低，6例患者的EPSP不可测量。我们假设这反映了皮质运动神经元的损失。7例（16.7%）与其他患者表型相同的EPSP大于年龄预测值。这可能反映了ALS亚组中谷氨酸诱导的兴奋性毒性。1例慢性脊髓性肌萎缩患者EPSP正常。
Peristimulus time histograms (PSTHs) of discharging single motor units, recorded from the extensor digitorum communis (EDC) during randomly applied cortical magnetic stimulation, were obtained in 42 normal subjects aged 24 to 83 years and 42 patients with amyotrophic lateral sclerosis (ALS) aged 37 to 84 years. Normal subjects had an early period of increased firing probability occurring at about 20 msec poststimulus, reflecting an underlying compound excitatory postsynaptic potential (EPSP) induced by fast-conducting, descending volleys of the corticomotoneuronal core facilitating the single spinal motoneuron. There was an age-dependent, linear decline in the amplitude of the EPSP (r = 0.673). We estimated that by age 50 years about 35% of corticomotoneurons are lost or nonfunctioning in normal controls, Compared with age-matched controls, the EPSP in most patients with ALS was reduced, and it was unmeasurable in six. We postulate this reflects a loss of corticomotoneurons. Seven (16.7%) patients phenotypically the same as the others had EPSPs that were larger than age-predicted values. This may reflect glutamate-induced excitotoxicity in a subset of ALS. In a single patient with chronic spinal muscular atrophy the EPSP was normal.