Osipova Daria, Ahveninen Jyrki, Kaakkola Seppo, Jääskeläinen Iiro P, Huttunen Juha, Pekkonen Eero
Cognitive Brain Research Unit, Department of Psychology, University of Helsinki, P.O. Box 9 00014, Helsinki, Finland.
Clin Neurophysiol. 2003 Oct;114(10):1902-7. doi: 10.1016/s1388-2457(03)00165-2.
Scopolamine, a muscarinic receptor antagonist, can produce temporary cognitive impairments as well as electroencephalographic changes that partially resemble those observed in Alzheimer's disease. In order to test the sensitivity of spectral power and hemispheric coherence to changes in cholinergic transmission, we evaluated quantitative magnetoencephalogram (MEG) after intravenous injection of scopolamine.
MEG of 8 elderly healthy subjects (59-80 years) were measured with a whole-head magnetometer after intravenous injection of scopolamine. An injection of glycopyrrolate, a peripheral muscarinic antagonist, was used as the placebo in a double-blind, randomized, cross-over design. Spectral power and coherence were computed over 7 brain regions in 3 frequency bands.
Scopolamine administration increased theta activity (4-8 Hz) and resulted in the abnormal pattern of MEG desynchronization in eyes-open vs. eyes-closed conditions in the alpha band (8-13 Hz). These effects were most prominent over the posterior regions. Interhemispheric and left intrahemispheric coherence was significantly decreased in the theta band (4-8 Hz).
Spontaneous cortical activity at the theta and alpha range and functional coupling in the theta band are modulated by the cholinergic system. MEG may provide a tool for monitoring brain dynamics in neurological disorders associated with cholinergic abnormalities.
东莨菪碱是一种毒蕈碱受体拮抗剂，可产生暂时性认知障碍以及脑电图变化，这些变化部分类似于在阿尔茨海默病中观察到的变化。为了测试频谱功率和半球相干性对胆碱能传递变化的敏感性，我们在静脉注射东莨菪碱后评估了定量脑磁图（MEG）。
在8名老年健康受试者（59 - 80岁）静脉注射东莨菪碱后，用全头磁强计测量其MEG。在双盲、随机、交叉设计中，使用外周毒蕈碱拮抗剂格隆溴铵注射作为安慰剂。计算3个频段内7个脑区的频谱功率和相干性。
给予东莨菪碱后增加了θ波活动（4 - 8Hz），并导致α波频段（8 - 13Hz）在睁眼与闭眼条件下MEG去同步化的异常模式。这些效应在后部区域最为明显。半球间和左侧半球内相干性在θ波频段（4 - 8Hz）显著降低。
胆碱能系统调节θ波和α波范围内的自发皮质活动以及θ波频段的功能耦合。MEG可能为监测与胆碱能异常相关的神经疾病中的脑动力学提供一种工具。
