Impaired modulation of intracortical inhibition in focal hand dystonia.
Impaired modulation of intracortical inhibition in focal hand dystonia.
复制标题
局灶性手部肌张力障碍的皮质内抑制调节受损。
DOI：
10.1093/cercor/bhh017
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发表时间：
2004
期刊：
影响因子：
3.7
通讯作者：
W. Byblow
中科院分区：
文献类型：
--
作者：
C. Stinear;W. Byblow
先前的研究表明，皮质内抑制（ICI）在塑造初级运动皮层的输出方面发挥着重要作用，并且局灶性手肌张力障碍（FHD）患者的 ICI 可能会受到损害。本研究探讨了执行阶段性食指弯曲任务期间 ICI 的肌肉特异性和时间调节。八名对照受试者和七名 FHD 受试者被要求将惯用手放在电脑鼠标上，并用食指用 1 Hz 听觉节拍器及时按下鼠标按钮，同时保持手的其余部分尽可能放松。当受试者处于休息状态以及任务的“开启”和“关闭”阶段时，记录第一背侧骨间肌 (FDI) 和拇短展肌 (APB) 对单脉冲和成对脉冲经颅磁刺激的反应。对于运动期间的对照对象 (i)。正如预期的那样，FDI 运动诱发电位 (MEP) 振幅和预触发肌电图增加，ICI 减少，以及 (ii)。 APB 的 MEP 振幅或预触发 EMG 没有显着促进，这与运动期间 ICI 显着增加相关。这可能有助于防止这块肌肉不必要的激活。虽然 FHD 受试者对于 FDI 和 APB 表现出相同的 MEP 振幅和预触发 EMG 调制模式，但他们的 ICI 水平不受任务表现的调节。尽管受试者组之间在休息时观察到的 ICI 水平没有差异。这些发现表明，FHD 与执行精确体力任务期间 ICI 调节受损有关，这可能导致 M1 输出缺乏特异性以及肌张力障碍症状的发生。
Previous studies have shown that intracortical inhibition (ICI) plays an important role in shaping the output from primary motor cortex, and that ICI may be impaired in people with Focal Hand Dystonia (FHD). This study explored the muscle-specificity and temporal modulation of ICI during the performance of a phasic index finger flexion task. Eight control subjects and seven with FHD were asked to rest their dominant hand upon a computer mouse, and depress the mouse button using their index finger in time with a 1 Hz auditory metronome, while keeping the rest of their hand as relaxed as possible. Responses to single and paired-pulse transcranial magnetic stimulation were recorded from the first dorsal interosseous (FDI) and abductor pollicis brevis (APB) muscles while subjects were at rest and during 'on' and 'off' phases of the task. For control subjects during the movement (i). FDI motor evoked potential (MEP) amplitude and pretrigger EMG increased, and ICI decreased, as expected, and (ii). there was no significant facilitation of MEP amplitude or pretrigger EMG for APB, which was associated with a significant increase in ICI during the movement. This may have helped prevent the unwanted activation of this muscle. While FHD subjects demonstrated the same patterns of modulation of both MEP amplitude and pretrigger EMG for both FDI and APB, their levels of ICI were not modulated by task performance. This was despite no difference between subject groups in the level of ICI observed at rest. These findings suggest that FHD is associated with impaired modulation of ICI during performance of a precise manual task, which may contribute to a lack of specificity in the output from M1 and the development of dystonic symptoms.