意識在學習記憶中的角色到現今仍未完全明瞭。過去研究發現即使在缺乏完整意識的麻醉狀態下，仍具有形成記憶的可能，特別是內隱記憶。而麻醉藥劑的特性與學習作業的本質可能都會影響麻醉下學習的效果。本論文選用右美托嘧啶(dexmedetomidine, DEX)，一種α2型腎上腺素致效劑，作為行為實驗用的麻醉藥。並透過改良後的抑制型逃避學習作業來探討麻醉下習得恐懼制約的可能。首先，初步探索性實驗發現，在DEX麻醉下反覆進行電擊與暗箱的配對訓練之後動物可以習得恐懼制約。接下來以這個訓練程序為基礎，進一步解析何項程序對麻醉下學習是重要的。結果顯示，第一天動物探索整個環境以及每天麻醉下電擊訓練前暴露在沒有電擊的亮箱區域對這個學習都扮演重要角色。再者，暴露在亮箱的階段若是被麻醉，學習效果便會稍微減弱。本論文也檢測訓練前於周邊注射腎上腺素對麻醉下學習的影響，結果顯示腎上腺素能促進麻醉下學習，讓沒有受到亮箱暴露階段的動物也能在麻醉下學習，但是動物仍需要在第一天探索過整個實驗箱環境。最後，利用永久性毀除手術或顱內微量注射暫時性抑制基底外側杏仁核或背側海馬迴功能，來瞭解這兩個區域在麻醉下學習的重要性。實驗結果發現這兩個區域受到毀除後，動物皆無法在麻醉下學習。另外，基底外側杏仁核在電擊訓練階段被抑制會導致動物無法在麻醉下學習，但在亮箱暴露階段被抑制則仍可學會。背側海馬迴在亮箱暴露階段受到抑制時會損害學習，電擊訓練階段有類似的趨勢但未達統計顯著。總之，本篇論文成功地建立麻醉下學習抑制性逃避學習作業的程序，且初步探索腎上腺素對此學習的促進效果，以及杏仁核與海馬迴在此學習中扮演的角色。希冀未來能延續此成果，藉由更廣泛而深入地研究各種麻醉狀態下的學習記憶探討意識所扮演的角色。

Anesthesia may interfere with brain and cognitive function, but animals and human still can perform certain kinds of learning and memory under anesthesia. These lines of evidence indicate that fully consciousness may not be required for all kind of learning. The aim of present study is to establish a training protocol of a modified inhibitory avoidance (IA) task when rats were anesthetized by dexmedetomidine (DEX). In the first experiment, anesthetized rats showed improved learning after repeated training sessions. We further examined which part of the procedure is important to the learning under anesthesia. Our results showed that free exploration of the entire apparatus, and exposure to the light chamber (light-exposure) under anesthesia are important. We also demonstrated that even light-exposure was performed under anesthesia, rats can still acquire this learning. In addition, we found that epinephrine enhanced the learning under DEX-anesthesia. Finally, we investigated the neural mechanism underlying this learning. Lesions of the amygdala, basolateral amygdala (BLA) or dorsal hippocampus (DH) caused impaired memory retention. Furthermore, infusion of lidocaine into the BLA during dark-shock pairing stage impaired this learning. In contrast, infusion of lidocaine into the DH during light-exposure stage impaired this learning. These findings are consistent with those results from awake animals: the hippocampus is involved in spatial related memory, whereas the amygdala is involved in aversive learning. Further experiments are required to investigate the difference between the learning under anesthesia or awake.

陳可欣(2017)。「恐懼條件學習改變得麻效鎮靜狀態大鼠之血氧濃度信號與功能性連結」(未出版之博士論文)。國立台灣大學心理學研究所。
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