Human Motor Control Laboratory, School of Psychology, University of Tasmania, Hobart, Tasmania, Australia.
J Neurophysiol. 2013 Sep;110(5):1062-9. doi: 10.1152/jn.00075.2013. Epub 2013 Jun 12.
A disruptive transcranial magnetic stimulation (TMS) approach was used to determine whether the increased frontal activation and reduced hemispheric laterality brain activation patterns observed in older adults during motor tasks play a functional role. Young and older adults abducted their left index finger as soon as possible after a visual imperative signal presented 500 ms after a warning signal. TMS was applied to the dorsal premotor (PMd) or primary motor (M1) cortex in the left or right hemisphere at seven times during response preparation and execution. Both groups exhibited faster reaction times in their left hand after stimulation of the left PMd (i.e., ipsilateral to the responding hand) relative to trials with no TMS, indicating a functional role of the left PMd in the regulation of impulse control. This result also suggests that the function of the left PMd appears to be unaffected by the healthy aging process. Right M1 TMS resulted in a response time delay in both groups. Only for older adults did left M1 stimulation delay responses, suggesting the involvement of ipsilateral motor pathways in the preparation of motor actions in older adults.
一种干扰性经颅磁刺激（TMS）方法被用于确定在运动任务中观察到的老年人额部激活增加和大脑半球侧化激活模式减少是否具有功能作用。年轻和老年受试者在警告信号后 500 毫秒出现视觉命令信号后，尽快将左手食指外展。TMS 在反应准备和执行过程中的 7 个时间点施加于左侧或右侧背侧运动前皮质（PMd）或初级运动皮质（M1）。在没有 TMS 的情况下，与试验相比，左侧 PMd（即与反应手同侧）刺激后，两组的左手反应时间都更快，这表明左侧 PMd 在调节冲动控制方面具有功能作用。这一结果还表明，左侧 PMd 的功能似乎不受健康衰老过程的影响。右侧 M1 的 TMS 导致两组的反应时间延迟。只有对于老年受试者，左侧 M1 刺激会延迟反应，这表明在老年受试者中，同侧运动通路参与了运动动作的准备。
