EEG 40 Hz Coherence Decreases in REM Sleep and Ketamine Model of Psychosis
EEG 40 Hz Coherence Decreases in REM Sleep and Ketamine Model of Psychosis
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DOI：
10.3389/fpsyt.2018.00766
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发表时间：
2019-01-17
影响因子：
4.7
通讯作者：
Torterolo, Pablo
中科院分区：
文献类型：
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作者：
Castro-Zaballa, Santiago;Cavelli, Matias Lorenzo;Torterolo, Pablo
认知过程在清醒时通过皮层和皮层下区域之间的广泛相互作用来进行。在精神病等精神疾病中，这些过程会发生改变。有趣的是，大多数梦都发生在REM睡眠中，与精神病有着共同的电生理学、药理学和神经化学特征。正因为如此，REM睡眠被认为是精神病的自然模型。氯胺酮是一种非竞争性N-甲基-D-天冬氨酸（NMDA）受体拮抗剂，在亚麻醉剂量下可诱导人类和动物的拟精神病样作用，并用作精神病的药理学模型。脑电图（EEG）的伽马频带（主要在约40 Hz）中的振荡已经涉及认知功能。因此，本研究旨在分析猫在自然（REM睡眠）和药理学（亚麻醉剂量的氯胺酮）精神病模型中的EEG低伽马（30-45 Hz）频带功率和相干性。这些结果与警觉（AW）和安静觉醒（OW）以及非REM（NREM）睡眠期间的伽马活动进行了比较。五只猫长期准备多导睡眠图记录，在不同的皮层区域的电极。获得基础记录，并将氯胺酮（5、10和15 mg/kg，i.m.）被管理。在上述条件下分析伽马活性（功率和相干性）。与清醒和NREM睡眠相比，氯胺酮给药后，所有研究的皮质区域的伽马相干性降低;在REM睡眠期间观察到相同的相干性。相反，氯胺酮下的γ功率相对较高，与OW和REM睡眠相似。我们的结论是，在两个实验模型的精神病皮质区之间的功能相互作用在伽马频带减少。这种伽马频率活动的分离可能与做梦和精神病共有的认知特征有关。
Cognitive processes are carried out during wakefulness by means of extensive interactions between cortical and subcortical areas. In psychiatric conditions, such as psychosis, these processes are altered. Interestingly, REM sleep where most dreams occurs, shares electrophysiological, pharmacological, and neurochemical features with psychosis. Because of this fact, REM sleep is considered a natural model of psychosis. Ketamine is a non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist that at sub-anesthetic dose induces psychotomimetic-like effects in humans and animals, and is employed as a pharmacological model of psychosis. Oscillations in the gamma frequency band of the electroencephalogram (EEG), mainly at about 40 Hz, have been involved in cognitive functions. Hence, the present study was conducted to analyze the EEG low gamma (30-45 Hz) band power and coherence of the cat, in natural (REM sleep) and pharmacological (sub-anesthetic doses of ketamine) models of psychosis. These results were compared with the gamma activity during alert (AW) and quiet wakefulness (OW), as well as during non-REM (NREM) sleep. Five cats were chronically prepared for polysomnographic recordings, with electrodes in different cortical areas. Basal recordings were obtained and ketamine (5, 10, and 15 mg/kg, i.m.) was administrated. Gamma activity (power and coherence) was analyzed in the abovementioned conditions. Compared to wakefulness and NREM sleep, following ketamine administration gamma coherence decreased among all cortical regions studied; the same coherence profile was observed during REM sleep. On the contrary, gamma power was relatively high under ketamine, and similar to OW and REM sleep. We conclude that functional interactions between cortical areas in the gamma frequency band decrease in both experimental models of psychosis. This uncoupling of gamma frequency activity may be involved in the cognitive features shared by dreaming and psychosis.