Axmacher Nikolai, Helmstaedter Christoph, Elger Christian E, Fell Juergen
Department of Epileptology, University of Bonn, 53105 Bonn, Germany.
Neural Plast. 2008;2008:563028. doi: 10.1155/2008/563028.
Interregional interactions of oscillatory activity are crucial for the integrated processing of multiple brain regions. However, while the EEG in virtually all brain structures passes through substantial modifications during sleep, it is still an open question whether interactions between neocortical and medial temporal EEG oscillations also depend on the state of alertness. Several previous studies in animals and humans suggest that hippocampal-neocortical interactions crucially depend on the state of alertness (i.e., waking state or sleep). Here, we analyzed scalp and intracranial EEG recordings during sleep and waking state in epilepsy patients undergoing presurgical evaluation. We found that the amplitudes of oscillations within the medial temporal lobe and the neocortex were more closely correlated during sleep, in particular during non-REM sleep, than during waking state. Possibly, the encoding of novel sensory inputs, which mainly occurs during waking state, requires that medial temporal dynamics are rather independent from neocortical dynamics, while the consolidation of memories during sleep may demand closer interactions between MTL and neocortex.
振荡活动的区域间相互作用对于多个脑区的整合处理至关重要。然而，尽管几乎所有脑结构中的脑电图在睡眠期间都会经历实质性改变，但新皮质与内侧颞叶脑电图振荡之间的相互作用是否也取决于警觉状态仍是一个悬而未决的问题。先前在动物和人类中的几项研究表明，海马体与新皮质的相互作用关键取决于警觉状态（即清醒状态或睡眠状态）。在此，我们分析了接受术前评估的癫痫患者在睡眠和清醒状态下的头皮和颅内脑电图记录。我们发现，内侧颞叶和新皮质内振荡的振幅在睡眠期间，尤其是在非快速眼动睡眠期间，比在清醒状态下更密切相关。可能，主要发生在清醒状态下的新感觉输入的编码要求内侧颞叶动力学与新皮质动力学相当独立，而睡眠期间记忆的巩固可能需要内侧颞叶与新皮质之间更密切的相互作用。
