Liu X, Branston N M, Kawauchi M, Jellinek D A, Symon L
Gough-Cooper Department of Neurological Surgery, Institute of Neurology, London, U.K.
Electroencephalogr Clin Neurophysiol. 1992 Jun;85(3):209-14. doi: 10.1016/0168-5597(92)90134-w.
In 7 baboons maintained under propofol anaesthesia, pyramidal tract responses were related to the corresponding peripheral EMG evoked by electrical stimulation of the motor cortex under conditions of focal cortical ischaemia. Pyramidal responses were recorded epidurally at the C5 level and the EMG was recorded from the contralateral hand or foot muscle using subdermal needle electrodes. Cortical ischaemia was produced by transorbital occlusion of the common anterior cerebral artery, and regional cortical blood flow was measured by the hydrogen clearance method. In the normally perfused brain, the later I waves of the C5 response required a lower stimulus strength to elicit them than the earlier I1 wave. It was more difficult to record the EMG from the hand than from the foot following stimulation of the corresponding cortex even though the C5 responses were always obtained in both cases. With moderate ischaemia, the later I waves were selectively abolished, leaving the D and I1 waves. EMG amplitude was significantly correlated with cortical blood flow (r = 0.88, P less than 0.005), and the threshold of cortical flow for the EMG was 10-13 ml/100 g/min. Our results indicate that changes in amplitude of the late I waves and particularly of the EMG are sensitive indicators of cortical ischaemia.
在7只接受丙泊酚麻醉的狒狒中，在局灶性皮质缺血的情况下，锥体束反应与电刺激运动皮质所诱发的相应外周肌电图相关。锥体反应在C5水平硬膜外记录，肌电图使用皮下针电极从对侧手部或足部肌肉记录。通过经眶阻断大脑前动脉主干产生皮质缺血，并用氢清除法测量局部皮质血流量。在正常灌注的大脑中，C5反应的较晚I波比早期I1波需要更低的刺激强度来引出。尽管在两种情况下均总能获得C5反应，但刺激相应皮质后，从手部记录肌电图比从足部更困难。在中度缺血时，较晚的I波被选择性消除，仅留下D波和I1波。肌电图幅度与皮质血流量显著相关（r = 0.88，P < 0.005），肌电图的皮质血流阈值为10 - 13 ml/100 g/min。我们的结果表明，较晚I波尤其是肌电图幅度的变化是皮质缺血的敏感指标。
