Dynamics of Ketamine-induced Loss and Return of Consciousness across Primate Neocortex
Dynamics of Ketamine-induced Loss and Return of Consciousness across Primate Neocortex
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DOI：
10.1097/aln.0000000000003159
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发表时间：
2020-04-01
期刊：
影响因子：
8.8
通讯作者：
Ishizawa, Yumiko
中科院分区：
文献类型：
--
作者：
Ballesteros, Jesus J.;Huang, Pamela;Ishizawa, Yumiko
背景：氯胺酮是一种非竞争性N-甲基-d-天冬氨酸拮抗剂，在脑电图中具有独特的电生理特征。然而，氯胺酮诱导的意识丧失的机制尚不清楚。作者研究了氯胺酮引起的意识丧失和恢复的神经元动力学，以及多感觉处理是如何修改的灵长类neocortical.Methods：作者进行了皮层内记录的局部场电位和单个单位的活动，在氯胺酮引起的意识状态改变的躯体感觉和腹侧前运动网络。这些动物接受了训练，执行按住按钮的任务，以表明警惕性。在每次试验中，无论他们的行为反应如何，都随机对面部或声音进行吹气。氯胺酮输注60 min。结果：氯胺酮引起的意识丧失过程中确定的高β-γ振荡的逐渐演变。缓慢的振荡似乎在氯胺酮麻醉的后期发展。在伽马振荡逐渐向β频率漂移期间，观察到意识恢复和麻醉前性能水平恢复（性能恢复）。氯胺酮诱导的意识丧失、意识恢复和性能恢复都是在动力学逐渐变化的过程中确定的，与丙泊酚诱导的意识丧失和意识恢复时的突然神经变化不同。多感觉反应表明，在氯胺酮麻醉期间，抽吸诱发电位和对抽吸的单单位放电反应都被保留，但声音反应被选择性地减弱。单位与抑制的反应和双峰反应出现抑制氯胺酮和延迟recovery.Conclusions：氯胺酮产生独特的皮质内动力学在其改变的意识状态，这表明从根本上不同的神经元过程从异丙酚。逐渐变化的动力学表明持续的意识或做梦状态，而在氯胺酮下没有反应，直到其更深的阶段与缓慢的δ振荡。在氯胺酮麻醉期间，躯体感觉处理得以保留，但多感觉处理似乎在氯胺酮下和恢复过程中减少。
Background:Ketamine is a noncompetitive N-methyl-d-aspartate antagonist and is known for unique electrophysiologic profiles in electroencephalography. However, the mechanisms of ketamine-induced unconsciousness are not clearly understood. The authors have investigated neuronal dynamics of ketamine-induced loss and return of consciousness and how multisensory processing is modified in the primate neocortex.Methods:The authors performed intracortical recordings of local field potentials and single unit activity during ketamine-induced altered states of consciousness in a somatosensory and ventral premotor network. The animals were trained to perform a button holding task to indicate alertness. Air puff to face or sound was randomly delivered in each trial regardless of their behavioral response. Ketamine was infused for 60 min.Results:Ketamine-induced loss of consciousness was identified during a gradual evolution of the high beta-gamma oscillations. The slow oscillations appeared to develop at a later stage of ketamine anesthesia. Return of consciousness and return of preanesthetic performance level (performance return) were observed during a gradual drift of the gamma oscillations toward the beta frequency. Ketamine-induced loss of consciousness, return of consciousness, and performance return are all identified during a gradual change of the dynamics, distinctive from the abrupt neural changes at propofol-induced loss of consciousness and return of consciousness. Multisensory responses indicate that puff evoked potentials and single-unit firing responses to puff were both preserved during ketamine anesthesia, but sound responses were selectively diminished. Units with suppressed responses and those with bimodal responses appeared to be inhibited under ketamine and delayed in recovery.Conclusions:Ketamine generates unique intracortical dynamics during its altered states of consciousness, suggesting fundamentally different neuronal processes from propofol. The gradually shifting dynamics suggest a continuously conscious or dreaming state while unresponsive under ketamine until its deeper stage with the slow-delta oscillations. Somatosensory processing is preserved during ketamine anesthesia, but multisensory processing appears to be diminished under ketamine and through recovery.