Motor cortex excitability in stiff-person syndrome.
Motor cortex excitability in stiff-person syndrome.
复制标题
僵人综合症中运动皮层的兴奋性。
DOI：
10.1093/brain/123.11.2231
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
Floeter,MK
中科院分区：
文献类型：
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作者：
Sandbrink,F;Syed,NA;Fujii,MD;Dalakas,MC;Floeter,MK
僵人综合征(SPS)的肌肉僵硬是由运动单位的连续非自愿放电引起的，这种运动单位被认为是由自身免疫介导的GABA能抑制神经元功能障碍引起的。我们推测，仅从脊髓神经元间失去GABA能输入不足以产生运动神经元的紧张性放电，并且脊髓上过度兴奋也可能起作用。为了确定SPS是否与棘上GABA能神经元功能障碍有关，我们评估了七名SPS患者和七名年龄匹配的健康志愿者经颅磁刺激(TMS)后运动皮质的兴奋性。SPS患者中枢运动传导时间正常，小腿肌肉运动诱发电位(MEP)阈值正常，MEP刺激-反应募集曲线正常，静息手部和腿部肌肉TMS强度增加。腿部肌肉皮质静止期缩短。当从拇短展肌记录时，使用配对的脉冲TMS范式和阈值下的条件反射刺激，评估皮层内的抑制和兴奋。患者在短时间间隔内抑制减少，促进作用显著增加。使用配对的阈值上TM，患者在20ms和40ms的间隔表现出更强的易化性。这些结果表明，SPS的运动皮质具有高度兴奋性，这可能是由于脊髓上的GABA能神经元受损，导致抑制性和兴奋性皮质内回路之间的平衡受损。
Muscle stiffness in stiff-person syndrome (SPS) is produced by continuous, involuntary firing of motor units that is thought to be caused by an autoimmune mediated dysfunction of GABA-ergic inhibitory neurones. We have postulated that the loss of GABA-ergic inputs from spinal interneurones alone is insufficient to produce tonic firing of motor neurones and that excessive supraspinal excitation could also play a role. To determine whether SPS is associated with dysfunction in supraspinal GABA-ergic neurones, we assessed the excitability of the motor cortex with transcranial magnetic stimulation (TMS) in seven SPS patients and seven age-matched healthy volunteers. SPS patients had normal central motor conduction times, normal thresholds for motor evoked potentials (MEPs) in leg muscles, and a normal MEP stimulus versus response recruitment curve with increasing TMS intensities in resting hand and leg muscles. Cortical silent periods were shortened in leg muscles. Intracortical inhibition and excitation were assessed while recording from the abductor pollicis brevis, using a paired pulse TMS paradigm with subthreshold conditioning stimuli. Patients had decreased inhibition and markedly increased facilitation at short intervals. Using paired suprathreshold TMS, patients exhibited increased facilitation at 20- and 40-ms intervals. These results point to a hyperexcitability of the motor cortex in SPS, which could be explained by impairment of supraspinal GABA-ergic neurones, leading to an impaired balance between inhibitory and excitatory intracortical circuitry.