Buchwald J S, Rubinstein E H, Schwafel J, Strandburg R J
Department of Physiology, UCLA School of Medicine 90024.
Electroencephalogr Clin Neurophysiol. 1991 Jul-Aug;80(4):303-9. doi: 10.1016/0168-5597(91)90114-d.
The effects of a cholinergic antagonist (scopolamine) and agonist (physostigmine) on the auditory middle latency evoked responses (MLRs) were studied in 7 normal male volunteers. Scalp recordings were made from a central (Cz) electrode referenced to linked ear lobes on one channel and to a non-cephalic, sternovertebral reference on a second channel. Three components were statistically analyzed for changes in latency and amplitude: Pa, with peak positivity in the 25-40 msec latency range, Nb, with peak negativity 40-50 msec, and P1, with peak positivity 50-65 msec. Control recordings included responses to click rates of 1, 5, 8 and 10/sec; as has been previously reported, P1 showed a marked decrease and disappeared at the faster rates of stimulation whereas Pa showed no change in amplitude. Intravenous injections of scopolamine resulted in a rapid and complete disappearance of P1 and a slight increase in Pa; concurrently, the subjects reported feeling drowsy but were awake with eyes open through the recordings. Subsequent injections of physostigmine resulted in a rapid reversal of the scopolamine effects so that the subjects became alert, Pa decreased, and P1 reappeared and increased to control amplitudes. Rapid click rates caused P1 to diminish, as in the control period, indicating a common P1 recovery cycle in both the control and physostigmine conditions. These data are discussed in terms of the hypothesis that the P1 generator system is comprised of a cholinergic brain-stem-thalamic component of the ascending reticular activating system.
在7名正常男性志愿者中研究了胆碱能拮抗剂（东莨菪碱）和激动剂（毒扁豆碱）对听觉中潜伏期诱发反应（MLRs）的影响。在一个通道上，以连接耳垂为参考电极，从头顶中央（Cz）电极进行头皮记录；在另一个通道上，以非头部的胸骨脊椎为参考电极。对三个成分的潜伏期和波幅变化进行了统计学分析：Pa，在25 - 40毫秒潜伏期范围内出现正向峰值；Nb，在40 - 50毫秒出现负向峰值；P1，在50 - 65毫秒出现正向峰值。对照记录包括对每秒1、5、8和10次的点击速率的反应；如先前报道，在较快的刺激速率下，P1波幅显著降低并消失，而Pa波幅无变化。静脉注射东莨菪碱导致P1迅速完全消失，Pa略有增加；同时，受试者报告感到困倦，但在记录过程中睁着眼睛保持清醒。随后注射毒扁豆碱导致东莨菪碱的作用迅速逆转，受试者变得警觉，Pa降低，P1重新出现并增加到对照波幅。快速点击速率导致P1像在对照期一样减小，表明在对照和毒扁豆碱条件下P1有共同的恢复周期。根据P1发生器系统由上行网状激活系统的胆碱能脑干 - 丘脑成分组成这一假说对这些数据进行了讨论。
