Abstract Abundant evidence from slow wave sleep, anesthesia, coma, and epileptic seizures links high-voltage, slow electroencephalogram (EEG) activity to loss of consciousness. This well-established correlation is challenged by the observation that children with Angelman syndrome (AS), while fully awake and displaying volitional behavior, display a hypersynchronous delta (1–4 Hz) frequency EEG phenotype typical of unconsciousness. Because the trough of the delta oscillation is associated with down-states in which cortical neurons are silenced, the presence of volitional behavior and wakefulness in AS amidst diffuse delta rhythms presents a paradox. Moreover, high-voltage, slow EEG activity is generally assumed to lack complexity, yet many theories view functional brain complexity as necessary for consciousness. Here, we use abnormal cortical dynamics in AS to assess whether EEG complexity may scale with the relative level of consciousness despite a background of hypersynchronous delta activity. As characterized by multiscale metrics, EEGs from 35 children with AS feature significantly greater complexity during wakefulness compared with sleep, even when comparing the most pathological segments of wakeful EEG to the segments of sleep EEG least likely to contain conscious mentation and when factoring out delta power differences across states. These findings (i) warn against reverse inferring an absence of consciousness solely on the basis of high-amplitude EEG delta oscillations, (ii) corroborate rare observations of preserved consciousness under hypersynchronization in other conditions, (iii) identify biomarkers of consciousness that have been validated under conditions of abnormal cortical dynamics, and (iv) lend credence to theories linking consciousness with complexity.

中文翻译：

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高压弥散性三角律与安格曼综合症的清醒意识和复杂性相吻合

摘要慢波睡眠，麻醉，昏迷和癫痫发作的大量证据将高电压，缓慢的脑电图（EEG）活动与意识丧失联系在一起。观察发现，具有安格曼综合症（AS）的儿童在完全清醒并表现出自愿行为的同时，表现出超同步三角洲（1-4 Hz）频率的EEG表型，这是无意识的典型现象，从而挑战了这一公认的相关性。因为三角洲振荡的低谷与皮层神经元沉默的下降状态有关，所以在弥漫性三角洲节律中，AS的意志行为和清醒性存在悖论。此外，通常认为高电压，缓慢的脑电活动缺乏复杂性，但是许多理论认为功能性大脑的复杂性是意识所必需的。这里，我们使用AS中异常的皮质动力学来评估脑电图复杂性是否与意识相对水平成正比，尽管背景存在高度同步的三角活动。以多尺度指标为特征，即使将唤醒性脑电图的大部分病理部分与最不可能包含清醒思维的睡眠脑电图部分进行比较，并且将三角洲能力排除在外，来自35名AS儿童的脑电图在觉醒期间的复杂性也要比睡眠时高得多。州之间的差异。这些发现（i）警告不要仅根据高振幅EEG三角波振荡来逆向推断意识缺失，（ii）确证其他条件下在超同步下保持意识的罕见观察，