|Title: ||1.海马beta受体在场景恐惧记忆读出中的作用 2.弥猴计数功能的研究|
|Degree Level: ||博士
|Issued Date: ||2005-06-16
|Degree Grantor: ||中国科学院上海生命科学研究院
|Place of Degree Grantor: ||上海生命科学研究院
|Abstract: ||第一部分: 大鼠海马CA1区b-受体与场景恐惧记忆的读出
研究表明，海马CA1区b-受体参与调控长时程增强（long-term potrntiation）和记忆巩固。但是， CA1区b-受体是否参与记忆读出，并不十分清楚。本实验中，我们应用场景恐惧条件化行为模型，研究CA1区b-受体在记忆读出中的作用。大鼠接受场景恐惧条件化训练，训练后1天或7天进行记忆保持测试，测试前30分钟在海马CA1区局部注射受体激动剂异丙肾上腺素(每侧10μg，1μl）或拮抗剂心得安(每侧15μg，1μl）。实验结果如下：注射异丙肾上腺素激活CA1区b-受体损害7天场景恐惧记忆的读出，但不影响1天场景恐惧记忆的读出；注射心得安阻断CA1区b-受体对1天和7天场景恐惧记忆的读出均没有影响。本研究提示，海马CA1区b-受体对场景恐惧记忆的读出不重要，b-受体激活对场景恐惧记忆的读出甚至是有害的。
|English Abstract: ||Part 1: β-Adrenoceptors in hippocampal CA1 and the retrieval of contextual fear memory
It is known that b-Adrenoceptors (b-ARs) in area CA1 are involved in regulating long-term potentiation and memory consolidation. However, it is not clear if b-ARs in area CA1 is also important in memory retrieval. In the present study, we used a hippocampus-dependent behavioral paradigm, contextual fear conditioning, to address the role of b-ARs in area CA1 in retrieval of contextual fear memory (CFM). Our results show that, infusion of the b-adrenergic agonist isoproterenol (10μg each side，1μl) into area CA1 impaired the retrieval of 7-day’s CFM (remote memory), but was without effect on the retrival of 1-day’s CFM (recent memory). Similar administration of the b-adrenergic antagonist propranolol (15μg each side，1μl) had no effect on the retrieval of both remote and recent CFMs. Our results suggest that the b-ARs in area CA1 are not critical, and even harmful, for the retrieval of contextual fear memory.
Part 2: Rhesus monkey can count from 1 to 7
It is known that non-human primates have a numerical concept and they can make relative numerical judgments. However, it is still in controversy if non-human primates posses counting ability. In the present study, we trained two rhesus monkeys to select a target pattern from a list of patterns presented sequentially on a touch screen. The monkeys were trained step by step: they were required to touch the first pattern in the 1-counting task, the 2nd one in the 1-to-2 counting task, the 3rd one in the 1-to-3 counting task, and so forth. Finally, the monkeys were required to select the 7th pattern. The inter-pattern-interval was randomized between 500~1500ms. Thus, the monkeys could not use a timing strategy to solve task problem. In the 1- through 1-to-6 counting tasks, each pattern had the same size, shape and color, while in the 1-to-7 counting task each pattern has different size, shape and color. After the monkeys learned each counting task with >85% correct rate in 5 consecutive daily sessions, they were introduced to the next step of training, with the counting load plus one. Up to now, both monkeys successfully learned the 1-to-7 counting task. The present study provides the 1st evidence that monkey has an ability to count sequentially-presented items up to seven.
Part 3: The monkey ventral prefrontal cortex is essential for counting performance
Behavioral studies have demonstrated that monkeys have numerical concept, they are able to make relative numerical judgment, and they have a competence to count items. Behavioral electrophysiological studies in monkeys have implicated the prefrontal cortex (PFC) and the parietal cortex in numerical judgments. However, little is known about the brain mechanism underlying counting performance. In the present study, we trained two rhesus monkeys on a 1-to-5 counting task: the monkeys were required to touch the 5th visual pattern from a set of patterns presented sequentially on a touch screen. We investigated how the task performance was affected following inactivation of the prefrontal cortical areas. Local infusion of the GABAergic agonist muscimol into the ventral prefrontal cortex produced a severe deficit in the counting performance: trials where the monkeys failed to select the 5th pattern to respond increased significantly. Similar infusion of muscimol into the dorsal prefrontal cortex was without effect. The present study suggests that the ventral prefrontal cortex plays a critical role in counting sequentially presented items.|
|Content Type: ||学位论文
|Appears in Collections:||神经所(总)_学位论文|
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