麻醉和清醒大鼠皮层神经元相互作用的关键变化
Critical Changes in Cortical Neuronal Interactions in Anesthetized and Awake Rats.
作者信息
Hudetz Anthony G, Vizuete Jeannette A, Pillay Siveshigan, Ropella Kristina M
机构信息
From the Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, Wisconsin (A.G.H., J.A.V., S.P.); and Department of Biomedical Engineering, Marquette University, Milwaukee, Wisconsin (J.A.V., K.M.R.).
出版信息
Anesthesiology. 2015 Jul;123(1):171-80. doi: 10.1097/ALN.0000000000000690.
BACKGROUND
Neuronal interactions are fundamental for information processing, cognition, and consciousness. Anesthetics reduce spontaneous cortical activity; however, neuronal reactivity to sensory stimuli is often preserved or augmented. How sensory stimulus-related neuronal interactions change under anesthesia has not been elucidated. In this study, the authors investigated the visual stimulus-related cortical neuronal interactions during stepwise emergence from desflurane anesthesia.
METHODS
Parallel spike trains were recorded with 64-contact extracellular microelectrode arrays from the primary visual cortex of chronically instrumented, unrestrained rats (N = 6) at 8, 6, 4, and 2% desflurane anesthesia and wakefulness. Light flashes were delivered to the retina by transcranial illumination at 5- to 15-s randomized intervals. Information theoretical indices, integration and interaction complexity, were calculated from the probability distribution of coincident spike patterns and used to quantify neuronal interactions before and after flash stimulation.
RESULTS
Integration and complexity showed significant negative associations with desflurane concentration (N = 60). Flash stimulation increased integration and complexity at all anesthetic levels (N = 60); the effect on complexity was reduced in wakefulness. During stepwise withdrawal of desflurane, the largest increase in integration (74%) and poststimulus complexity (35%) occurred before reaching 4% desflurane concentration-a level associated with the recovery of consciousness according to the rats' righting reflex.
CONCLUSIONS
Neuronal interactions in the cerebral cortex are augmented during emergence from anesthesia. Visual flash stimuli enhance neuronal interactions in both wakefulness and anesthesia; the increase in interaction complexity is attenuated as poststimulus complexity reaches plateau. The critical changes in cortical neuronal interactions occur during transition to consciousness.
背景
神经元相互作用是信息处理、认知和意识的基础。麻醉药可降低皮层自发活动；然而，神经元对感觉刺激的反应性通常得以保留或增强。麻醉状态下与感觉刺激相关的神经元相互作用如何变化尚未阐明。在本研究中，作者调查了在从地氟烷麻醉逐步苏醒过程中与视觉刺激相关的皮层神经元相互作用。
方法
使用64触点细胞外微电极阵列，在8%、6%、4%和2%地氟烷麻醉及清醒状态下，记录长期植入仪器、未受约束大鼠（N = 6）初级视觉皮层的平行峰电位序列。以5至15秒的随机间隔通过经颅照明向视网膜发送闪光。根据同时发生的峰电位模式的概率分布计算信息理论指标、整合度和相互作用复杂度，并用于量化闪光刺激前后的神经元相互作用。
结果
整合度和复杂度与地氟烷浓度呈显著负相关（N = 60）。在所有麻醉水平下，闪光刺激均增加了整合度和复杂度（N = 60）；在清醒状态下，对复杂度的影响减小。在逐步停用 地氟烷期间，整合度（74%）和刺激后复杂度（35%）的最大增加发生在达到4%地氟烷浓度之前——根据大鼠的翻正反射，该浓度与意识恢复相关。
结论
在麻醉苏醒过程中，大脑皮层中的神经元相互作用增强。视觉闪光刺激在清醒和麻醉状态下均增强神经元相互作用；随着刺激后复杂度达到平稳状态，相互作用复杂度的增加减弱。皮层神经元相互作用的关键变化发生在意识转变期间。
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