Samulack D D, Waters R S, Dykes R W, McKinley P A
Department of Physiology, McGill University, Montreal.
Can J Neurol Sci. 1990 Feb;17(1):24-9. doi: 10.1017/s0317167100029978.
Intracortical microstimulation (ICMS) was used to map the primary motor cortex of four adult female baboons, anesthetized with a mixture of halothane and nitrous oxide and supplemented with sodium pentobarbital. The sequence of observed muscle contractions in response to ICMS provided evidence of an orderly mototopic representation of the tongue, face, hand, forearm and upper body. A zone of cortex unresponsive to microstimulation was consistently observed at the border between the face and hand representation of the mototopic map. This zone was observed in all four animals and was consistent over time. Repeated confirmations of the unresponsive nature of these regions were obtained both early and late in the same experiment. No motor-unit responses or muscle contractions were detected by electromyographic (EMG) recording during stimulation of the unresponsive zones. The absence of both visually observed and EMG-recorded contractions and the fact that muscle contractions could be elicited from adjacent regions of cortex with ICMS as low as 1-5 microA provide compelling evidence that the finding reflects a true physiological condition rather than an experimental artifact.
采用皮层内微刺激（ICMS）对四只成年雌性狒狒的初级运动皮层进行映射，这些狒狒用氟烷和一氧化二氮的混合物麻醉，并辅以戊巴比妥钠。观察到的对ICMS作出反应的肌肉收缩序列为舌、面部、手、前臂和上身的有序运动定位表征提供了证据。在运动定位图的面部和手部表征之间的边界处，始终观察到一个对微刺激无反应的皮层区域。在所有四只动物中均观察到该区域，并且随时间保持一致。在同一实验的早期和晚期均反复证实了这些区域的无反应特性。在刺激无反应区域期间，通过肌电图（EMG）记录未检测到运动单位反应或肌肉收缩。视觉观察和EMG记录的收缩均不存在，并且使用低至1 - 5微安的ICMS可从相邻皮层区域诱发肌肉收缩，这一事实提供了令人信服的证据，表明该发现反映了一种真实的生理状况，而非实验假象。
