Tarkka I M, Treede R D, Bromm B
Institute of Physiology, University Hospital Eppendorf, Hamburg, Germany.
Acta Neurol Scand. 1992 Oct;86(4):359-64. doi: 10.1111/j.1600-0404.1992.tb05101.x.
The processing of a sensory stimulus leading to a simple motor command was studied with scalp-recorded long latency cortical potentials in humans. Two sensory modalities were tested in their ability to activate descending motor pathways: auditory stimuli and painful cutaneous stimuli produced by a CO2 laser. Subjects were asked to react to stimuli with voluntary index finger movements. The stimulus-related and movement-related cortical potentials were recorded simultaneously with five midline electrodes on the scalp. The auditory reaction time, measured from the stimulus to the onset of electromyogram (EMG), was faster (150 ms) than the laser reaction time (350 ms). The onset of EMG of finger movements occurred only after the first negative components following auditory or laser stimuli but before the positive components. The latency from the auditory negativity to the onset of EMG was about 50 ms and the latency from the laser negativity to the onset of EMG was about 110 ms. This finding indicates that not only the peripheral afferent conduction but also central processing takes longer in a pain-related somatosensory task than in an auditory task. The frontal peak of Motor Potential (fpMP), a cortical potential related to the sensory feedback from movement, occurred with a constant latency after the onset of EMG (100 ms) and was unaffected by the task.
利用头皮记录的人类长潜伏期皮质电位，研究了导致简单运动指令的感觉刺激处理过程。测试了两种感觉模态激活下行运动通路的能力：听觉刺激和二氧化碳激光产生的疼痛性皮肤刺激。要求受试者通过自愿的食指运动对刺激做出反应。刺激相关和运动相关的皮质电位通过头皮上的五个中线电极同时记录。从刺激到肌电图（EMG）开始测量的听觉反应时间（150毫秒）比激光反应时间（350毫秒）快。手指运动的EMG开始仅在听觉或激光刺激后的第一个负成分之后但在正成分之前出现。从听觉负波到EMG开始的潜伏期约为50毫秒，从激光负波到EMG开始的潜伏期约为110毫秒。这一发现表明，在与疼痛相关的体感任务中，不仅外周传入传导，而且中枢处理都比听觉任务花费更长的时间。运动电位的额叶峰值（fpMP）是一种与运动感觉反馈相关的皮质电位，在EMG开始后以恒定的潜伏期出现（100毫秒），并且不受任务影响。
