本研究操弄受試的食物剝奪程度以及鋰鹽（LiCl）去價值程序，觀察此兩種實驗操弄對於大白鼠舔舐行為的影響，以探討飢餓驅力調節完結行為的機制。實驗一連續觀察8天大白鼠舔舐15%蔗糖液的表現，結果顯示初期兩天剝奪受試和自由吃食受試的舔舐表現並沒有顯著差異，第三天起剝奪組才顯著高於自由吃食組。實驗二待大白鼠習於食物剝奪狀態下舔舐15%蔗糖液之後，進行僅舔舐空管的消除情境測試。實驗結果顯示將剝奪狀態改為自由吃食，不論有無接受誘因學習都不能降低受試舔舐空管的表現。實驗三則待大白鼠習於食物剝奪狀態下舔舐25%蔗糖液之後，接受空管測試（實驗三A、B、C）與舔水消除情境測試（實驗三B、C）。實驗三結果如同實驗二，將剝奪狀態改為自由吃食，不論有無接受誘因學習都不能降低受試舔舐空管或舔水的表現。實驗四使用柳橙香料配加蔗糖液（20%）進行舔舐訓練，以僅含柳橙香料水進行消除情境測試。實驗結果顯示受試不論是由剝奪狀態轉為自由吃食，或由自由吃食轉為剝奪，都顯示出當驅力高舔舐表現高或驅力低表現低的現象。實驗五進行鋰鹽去價值實驗，大白鼠先擁有舔飲柳橙香料糖精液（實驗五A）或草莓香料食鹽水（實驗五B）的經驗後，再進行鋰鹽去價值程序。實驗結果顯示大白鼠唯有舔舐香料糖精液或香料食鹽水後接受鋰鹽注射才能降低其舔舐香料水的表現；糖精－鋰鹽配對、糖精－鋰鹽配對後再舔飲一次糖精液，以及香料水－鋰鹽配對都無法降低受試舔飲香料水的表現。糖精或食鹽水只要和鋰鹽配對過，便能產生味覺嫌惡。本研究結論如下：（1）飢餓驅力調節舔舐行為的能力只顯現在舔飲蔗糖液以及舔舐柳橙香料水的消除情境測試中；（2）香料與糖精或香料與食鹽必須同時呈現與鋰鹽配對才能降低香料引發舔舐行為的能力。 / The effects of food deprivation and lithium chloride (LiCl)-induced devaluation on licking behavior were studied for the regulatory mechanism of hunger drive on licking behavior. The first experiment for measuring the licking of 15% sucrose solution for 8 days and found that deprived subjects did not lick more than non-deprived ones until the third day. In the second experiment, the rats trained to lick 15% sucrose in a food-deprivation state were shifted to a non-deprivation state and tested under extinction procedure by using the empty tube. This shift in deprivation did not suppress licking in empty tube test for subjects with or without incentive learning experiences. In the third experiment, the rats trained to lick 25% sucrose in a food-deprivation state were shifted to a non-deprivation state and tested in empty tube (Exp. 3A, B, C) or water-licking test (Exp. 3B, C) conditions. Independent of incentive learning, the shift in deprivation did not suppress licking in these two kinds of extinction conditions although the concentration of sucrose was increased. In the fourth experiment, rats were trained to lick 20% sucrose mixed with orange flavor and tested in orange flavor water-licking test condition. Deprived rats licked more than non-deprived ones in the test condition whether they were trained under deprivation or non-deprivation. In the fifth experiment, rats were trained to lick orange flavor saccharin solution (Exp. 5A) or strawberry flavor sodium chloride (NaCl) solution (Exp. 5B) and then tested by the LiCl devaluation procedure. Flavored saccharin or flavored NaCl paired with LiCl suppressed rats to lick flavored water. But none of saccharin paired with LiCl, incentive learning after saccharin devaluation, and flavored water paired with LiCl had any significant effect. Saccharin or NaCl paired with LiCl could induce taste aversion. In conclusion, hunger drive modulating licking behavior was only found in licking sucrose or the flavored water-licking test condition. Further, only flavored saccharin or flavored NaCl solutions paired with LiCl could suppress licking flavored water.

本研究以神經毒素ibotenic acid破壞不同尾核區域以及鋰鹽去價值程序為操弄變項，觀測此兩種實驗操弄對於大鼠之迷津行為之影響，進而探討標誌系統之行為內涵及神經機制。實驗所採用的作業為線索學習作業以及自我中心作業，分別代表標誌系統下的線索導引策略及體位導向策略。實驗一及實驗二在於檢驗尾核功能缺損對於大鼠迷津行為之影響，從探測嘗試發現大鼠在線索學習的行為表現需依賴砂紙線索的導引，而在自我中心作業之行為則不以環境刺激為依據（實驗一A、二A），顯示大鼠在各迷津作業的行為符合標誌系統的運作原則。神經機制之操弄結果顯示在記憶習得階段，尾核破壞之受試在線索學習作業上的表現並沒有顯著變差，尾核功能缺損並未導致學習的延宕或阻斷，其進步的速度仍與控制組相同（實驗一B）。相較於線索學習作業，尾核破壞之受試在自我中心作業上的表現則明顯變差，幾乎沒有進步的趨勢（實驗二B）。而在記憶保持階段，不管是線索學習作業或自我中心作業之表現皆會因尾核破壞而顯著變差（實驗一C、二C）。實驗三及實驗四則利用鋰鹽去價值程序降低食餌之誘因價值，觀測大鼠行為有無相對應改變。結果發現去價值程序的操弄只會影響到大鼠在自我中心作業的行為表現（實驗四），而不影響其在線索學習作業之行為（實驗三）。由此可知，兩種迷津作業所形成的記憶表徵是不同的，自我中心學習歷程會將增強物表徵在聯結單位中，而線索學習之習得歷程則不會。綜合上述實驗結果，標誌系統下確實有兩個不同空間行為機制，一個為線索導引策略，另一個為體位導向策略，雖皆受到尾核的調節，但調節的程度是不同的。不管是記憶習得或保持階段，尾核在體位導向策略的運作中皆扮演重要的角色，而在線索導引策略只參與了記憶保持歷程的運作。另外，兩個空間行為機制在學習內涵上也不盡相同，以線索導引策略為依據之空間行為會形成刺激反應(S-R)的聯結型態，而以體位導向策略為依據之空間行為則會形成反應及增強物(R-S*)聯結。 / This study investigated the neurobehavioral mechanisms of taxon system of spatial memory through manipulating lesions of subareas in the caudate nucleus by ibotenic acid and lithium chloride (LiCl)-induced reward devaluation. With respect to behavioral measurement in an eight-arm radial maze, a cue learning task and an egocentric task were used for testing the guidance and orientation hypotheses of taxon system, respectively. Data from probing procedures showed that the performance of rats in the cue learning task was impaired when the cue was removed, but the performance in the egocentric task was not affected by changing the context (Experiments 1A and 2A). These results indicate that behavior reactions in two tasks are corresponding to those two operational principles of taxon system. In terms of the acquisition, deficits were significantly produced by the lesion of the dorsomedial caudate on egocentric task, while the ibotenate lesions did not affect cue learning task (Experiments 1B and 2B). For retention test, the performances in both cue learning and egocentric tasks were impaired by dorsomedial caudate lesion, no such impairment was observed from dorsolateral and posterolateral caudate lesions (Experiments 1C and 2C). In the third and fourth experiments, LiCl devaluation procedure was employed to lower the reward value of the bait in the maze. This manipulation significantly impaired the performance of egocentric task but not that of the cue learning task. These results indicate that the memory representations in the two tasks used in the present study are different. The memory representation in the egocentric task contains the reinforcer, whereas that in the cue learning task is not necessarily relevant to the reinforcer. In conclusion, the guidance and orientation hypotheses can be differentiated as behavioral mechanisms existing in the taxon system of spatial memory. Although the caudate nucleus is critically important for the operation of both hypotheses, the degrees of this brain site to get involved are different. The caudate nucleus participates in the acquisition and retention of orientation hypothesis, but only in the retention of guidance hypothesis. In addition, behavioral performance of the spatial memory using guidance hypothesis is based on forming the association of stimulus and response (S-R), while that using orientation hypothesis is based on forming the association of response and reinforcer (R-S*).