Usami Kiyohide, Matsumoto Riki, Kobayashi Katsuya, Hitomi Takefumi, Shimotake Akihiro, Kikuchi Takayuki, Matsuhashi Masao, Kunieda Takeharu, Mikuni Nobuhiro, Miyamoto Susumu, Fukuyama Hidenao, Takahashi Ryosuke, Ikeda Akio
Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, 606-8507, Japan.
Department of Epilepsy, Movement Disorders and Physiology, Kyoto University Graduate School of Medicine, Kyoto, 606-8507, Japan.
Hum Brain Mapp. 2015 Nov;36(11):4714-29. doi: 10.1002/hbm.22948. Epub 2015 Aug 26.
Sleep-induced changes in human brain connectivity/excitability and their physiologic basis remain unclear, especially in the frontal lobe. We investigated sleep-induced connectivity and excitability changes in 11 patients who underwent chronic implantation of subdural electrodes for epilepsy surgery. Single-pulse electrical stimuli were directly injected to a part of the cortices, and cortico-cortical evoked potentials (CCEPs) and CCEP-related high-gamma activities (HGA: 100-200 Hz) were recorded from adjacent and remote cortices as proxies of effective connectivity and induced neuronal activity, respectively. HGA power during the initial CCEP component (N1) correlated with the N1 size itself across all states investigated. The degree of cortical connectivity and excitability changed during sleep depending on sleep stage, approximately showing dichotomy of awake vs. non-rapid eye movement (REM) [NREM] sleep. On the other hand, REM sleep partly had properties of both awake and NREM sleep, placing itself in the intermediate state between them. Compared with the awake state, single-pulse stimulation especially during NREM sleep induced increased connectivity (N1 size) and neuronal excitability (HGA increase at N1), which was immediately followed by intense inhibition (HGA decrease). The HGA decrease was temporally followed by the N2 peak (the second CCEP component), and then by HGA re-increase during sleep across all lobes. This HGA rebound or re-increase of neuronal synchrony was largest in the frontal lobe compared with the other lobes. These properties of sleep-induced changes of the cortex may be related to unconsciousness during sleep and frequent nocturnal seizures in frontal lobe epilepsy.
睡眠引起的人脑连接性/兴奋性变化及其生理基础仍不清楚，尤其是在额叶。我们调查了11例因癫痫手术而接受慢性硬膜下电极植入的患者睡眠引起的连接性和兴奋性变化。将单脉冲电刺激直接注入部分皮质，并从相邻和远处皮质记录皮质-皮质诱发电位（CCEP）和与CCEP相关的高伽马活动（HGA：100 - 200Hz），分别作为有效连接性和诱导神经元活动的指标。在所研究的所有状态下，初始CCEP成分（N1）期间的HGA功率与N1大小本身相关。睡眠期间皮质连接性和兴奋性的程度根据睡眠阶段而变化，大致呈现清醒与非快速眼动（REM）[NREM]睡眠的二分法。另一方面，REM睡眠部分具有清醒和NREM睡眠的特性，处于两者之间的中间状态。与清醒状态相比，单脉冲刺激尤其是在NREM睡眠期间会诱导连接性增加（N1大小）和神经元兴奋性增加（N1处HGA增加），随后立即出现强烈抑制（HGA降低）。HGA降低在时间上随后出现N2峰（第二个CCEP成分），然后在所有脑叶的睡眠期间HGA再次增加。与其他脑叶相比，这种HGA反弹或神经元同步性的再次增加在额叶中最大。皮质睡眠诱导变化的这些特性可能与睡眠期间的无意识状态以及额叶癫痫中频繁的夜间发作有关。
