Mimura O, Wanaka Y, Iwasaki Y, Ikeda N, Takubo K, Shimo-oku M
Department of Ophthalmology, Hyogo College of Medicine, Nishinomiya, Japan.
Nippon Ganka Gakkai Zasshi. 1990 Sep;94(9):786-91.
In 12 adult cats, pulsed magnetic stimuli were applied to the scalp, with the center of the stimulating coil over the interparietal bone. Recordings were obtained from the superior rectus, lateral rectus and inferior oblique muscles with concentric needle electrodes. In all cats, single muscle action potentials were recorded easily in all the muscles examined with latencies of 3.2-37.5 ms (mean 15.6ms). These responses disappeared after intravenous administration of pancuronium bromide. Furthermore, the elicited action potentials in the inferior oblique muscles disappeared by amputation of the inferior oblique branch of the oculomotor nerve. In some motor units, stronger stimuli shortened the latency of the responses. In most units, however, stimulus intensity did not influence the latency of responses over a wide range. The mean latency (15.6ms) is coincident with the latency of cortical spike potentials preceding voluntary saccades. This remarkable coincidence suggests that our pulsed magnetic stimuli have a very strong possibility of generation of human saccades. Thus, magnetic stimulation of the scalp may provide further information relevant to the normal operation of the oculomotor system.
对12只成年猫的头皮施加脉冲磁刺激，刺激线圈的中心位于顶间骨上方。使用同心针电极从直肌、外直肌和下斜肌进行记录。在所有猫中，在所检查的所有肌肉中都很容易记录到单肌动作电位，潜伏期为3.2 - 37.5毫秒（平均15.6毫秒）。静脉注射泮库溴铵后，这些反应消失。此外，动眼神经下斜支切断后，下斜肌中引发的动作电位消失。在一些运动单位中，较强的刺激缩短了反应的潜伏期。然而，在大多数单位中，刺激强度在很宽的范围内并不影响反应的潜伏期。平均潜伏期（15.6毫秒）与自愿性扫视之前的皮质尖峰电位潜伏期一致。这种显著的巧合表明，我们的脉冲磁刺激极有可能引发人类的扫视。因此，头皮磁刺激可能会提供与动眼系统正常运作相关的更多信息。
