Activities of the Primary and Supplementary Motor Areas Increase in Preparation and Execution of Voluntary Muscle Relaxation: An Event-Related fMRI Study
Activities of the Primary and Supplementary Motor Areas Increase in Preparation and Execution of Voluntary Muscle Relaxation: An Event-Related fMRI Study
复制标题
主要和辅助运动区的活动在自愿肌肉放松的准备和执行中增加：一项与事件相关的功能磁共振成像研究
作者：
K. Toma;M. Honda;T. Hanakawa;T. Okada;H. Fukuyama;A. Ikeda;S. Nishizawa;J. Konishi;H. Shibasaki
采用事件相关功能磁共振成像（fMRI）技术，观察了运动过程中脑功能的变化。受试者自愿放松或收缩右上肢肌肉。每种运动模式都有两个条件;一个需要关节运动，另一个不需要。使用回波平面1.5特斯拉MRI扫描仪，每秒获得一次覆盖主要运动区（M1）和辅助运动区（SMA）的五个轴向图像。一个会话包括60个动态扫描（即，60秒）。受试者进行单次运动试验（即，放松或收缩）在一个会议期间在他自己的时间。每项任务进行10次会议。在fMRI扫描期间，从右前臂肌肉监测肌电图（EMG）以识别运动起始。我们计算得到的fMRI信号和预期的血流动力学反应之间的相关性。肌肉松弛显示瞬时信号增加时间锁定到运动对侧M1和双侧SMA中的EMG偏移，其中在肌肉收缩中也观察到激活。SMA头端和尾端的激活体积在肌肉舒张时均显著大于肌肉收缩时（p < 0.05）。结果表明，随意性肌肉松弛的发生是由于兴奋的皮质脊髓投射神经元或皮质内抑制性中间神经元，或两者兼而有之，在M1和SMA，和SMA前和SMA本身在运动抑制中发挥重要作用。
Brain activity associated with voluntary muscle relaxation was examined by applying event-related functional magnetic resonance imaging (fMRI) technique, which enables us to observe change of fMRI signals associated with a single motor trial. The subject voluntarily relaxed or contracted the right upper limb muscles. Each motor mode had two conditions; one required joint movement, and the other did not. Five axial images covering the primary motor area (M1) and supplementary motor area (SMA) were obtained once every second, using an echoplanar 1.5 tesla MRI scanner. One session consisted of 60 dynamic scans (i.e., 60 sec). The subject performed a single motor trial (i.e., relaxation or contraction) during one session in his own time. Ten sessions were done for each task. During fMRI scanning, electromyogram (EMG) was monitored from the right forearm muscles to identify the motor onset. We calculated the correlation between the obtained fMRI signal and the expected hemodynamic response. The muscle relaxation showed transient signal increase time-locked to the EMG offset in the M1 contralateral to the movement and bilateral SMAs, where activation was observed also in the muscle contraction. Activated volume in both the rostral and caudal parts of SMA was significantly larger for the muscle relaxation than for the muscle contraction (p < 0.05). The results suggest that voluntary muscle relaxation occurs as a consequence of excitation of corticospinal projection neurons or intracortical inhibitory interneurons, or both, in the M1 and SMA, and both pre-SMA and SMA proper play an important role in motor inhibition.
DOI：
10.1073/pnas.95.3.773
发表时间：
1998-02-03
影响因子：
11.1
作者：
Rosen, BR;Buckner, RL;Dale, AM
通讯作者：
Dale, AM