1.初级视觉皮层功能，GABA系统功能在衰老过程中的变化; 2.奖赏机制，极低频磁场的生物学效应研究
文献类型：学位论文
| 作者 | 付玉 |
| 学位类别 | 博士 |
| 答辩日期 | 2008-06 |
| 授予单位 | 中国科学院研究生院 |
| 授予地点 | 北京 |
| 导师 | 马原野 |
| 关键词 | 老化 初级视觉皮层 衰老早期 戊巴比妥钠 氯胺酮 奖赏系统 眶额叶皮质 极低频磁场 Y-迷宫 空间认知功能 |
| 其他题名 | 1 THE FUNCTION OF PRIMARY VISUAL CORTEX AND GABA SYSTEM DURING SENESCENCE; 2 RESEARCHES ON THE REWARD MECHANISM AND THE BIOLOGICAL EFFECTS OF THE EXTREMELY LOW-FREQUENCY MAGNETIC FIELDS |
| 学位专业 | 神经生物学 |
| 中文摘要 | 1 初级视觉皮层功能，GABA系统功能在衰老过程中的变化 本章首先对衰老过程中神经形态学和神经电生理学上的研究进行了综述，然后报道了作者的博士学位论文研究工作。实验采用神经电生理的手段，探讨初级视觉皮层（primary visual cortex；V1）功能，以及GABA（gamma-aminobutyric acid）系统功能在衰老过程中的变化。 实验1和2均采用单细胞记录技术，检测了中年猴V1细胞的方位选择性、方向选择性、自发放和最大反应，并与年轻和老年猴进行对比；比较了年轻和老年猴V1细胞的感受野外周抑制能力。在实验3中，我们记录了年轻和中年大鼠在给予GABA直接或间接的激动剂，戊巴比妥钠或氯胺酮{通过拮抗NMDA（N-methyl-D-aspartate）受体}后，其皮层的EEG（electroencephalogram）活动，并分析与年龄相关的差异。结果如下： 实验1：中年猴V1细胞的方向选择性和自发放介于年轻猴和老年猴之间，而方位选择性和最大反应与年龄之间没有相关性。 实验2：感受野外周区的最优刺激明显降低了年轻和老年猴具有高方位选择性细胞的比例。同时，年轻猴所有细胞，以及老年猴高方位选择性细胞具有较高的最大抑制比，与它们相比，老年猴无明显方位偏好细胞的最大抑制比显著降低； 实验3：戊巴比妥钠注射后，在年轻和中年大鼠上，alpha (8-12 Hz) 和beta (12-20 Hz) 频段EEG功率增加，theta (4-8 Hz) 功率减少，这些变化在中年大鼠上较为明显。氯胺酮注射后，中年大鼠theta功率比年轻大鼠具有更大幅度的降低。 我们的结果表明，视觉皮层功能的下调在衰老早期就已发生，其机制可能与抑制系统功能普遍降低有关. 2 奖赏机制，极低频磁场的生物学效应研究 本章首先对自然奖赏和药物成瘾机制、极低频磁场生物学效应，以及极低频磁场对奖赏系统的影响进行了综述，然后报道了作者的博士论文研究工作。实验目的是探讨大鼠眶额叶皮质（orbitofrontal cortex；OFC）活动与食物奖赏刺激的相关性，以及极低频磁场对小鼠空间认知能力的影响。 实验1采用EEG记录技术，检测了大鼠OFC在食物奖赏和渴求过程中EEG各频段的功率变化。在实验2中，使用了一种探索型Y-迷宫实验范式，它仅依赖于啮齿类动物天生的探索欲望，避免了奖赏效应的干扰，利用此新型迷宫，我们检测了25和50 Hz磁场对小鼠空间识别记忆能力的影响。其结果如下： 实验1：大鼠OFC的delta频段（2-4 Hz）EEG活动与食物刺激显著相关，其相对功率在食物渴求时下降，在食物奖赏时升高。 实验2：与短时照射相比，长时的50 Hz磁场照射降低了小鼠对新异臂的探索能力，而25和50 Hz磁场暴露都不影响小鼠的活动力。 本研究表明，食物奖赏与OFC的delta频段EEG活动密切相关，而我们以前发现，大鼠和猴OFC的gamma（20-100 Hz）活动与吗啡成瘾相关，提示了OFC在自然奖赏和药物成瘾中具有不同的作用；另外，本实验首次证明，极低频磁场损害了小鼠不依赖于奖赏系统的空间认知能力，而我们先前发现，极低频磁场可以强化吗啡诱导的条件化位置偏好，从而说明极低频磁场对吗啡成瘾具有独特的生物学效应。 |
| 英文摘要 | 1 The function of primary visual cortex and GABA system during senescence The chapter reviewed studies on neuromorphology and neuroelectrophysiology about aging, and then reported our researches during my postgraduate period. With neuroelectrophysiology techoniques, we investigated changes in function of primary visual cortex (V1), as well as GABA system during senescence. In Experiment 1 and 2, with unit-recording techniques, the orientation and direction biases, spontaneous activities and peak responses were investigated in V1 cells in middle-aged monkeys, which were compared with those in young and old monkeys; the suppression indexes of surround region of the receptive field of V1 cells were also measured in young and old monkeys. In Experiment 3, we recorded the cortical EEG during pentobarbital (GABA agonist) or ketamine (NMDA antagonist indirectly activates GABAa receptor) anesthesia in young and aged rats. Our results are as follows: In Experiment 1, the direction biases and spontaneous activities in middle-aged monkey cells were in between young and old monkey cells. However, the orientation biases and peak responses were not correlated with age. In Experiment 2, in both age groups, the orientation biases decreased in cells that were biased for orientation when the optimal surround suppression was presented. However, cells showing no significant orientation selectivity more strongly reduced surround suppression indexes in old than in young monkeys. In Experiment 3, in both age groups, pentobarbital anaesthesia induced an increase in relative power in alpha and beta bands and a decrease in the theta band, but the degrees of these power variations were more marked in aged rats. Ketamine anaesthesia decreased relative power in the theta band, with aged rats showing more markedly decreased power. In brief, the functional deficits in visual cells appeared during the early stage of senescence, which may result from general degradation of intracortical inhibition with age. 2 Researches on the reward mechanism and the biological effects of the extremely low-frequency magnetic fields This chapter firstly reviewed the reward mechanism including natural rewards and drug addiction, the biological effects of the extremely low-frequency (ELF; 0–300 Hz) magnetic fields, and the influence of the ELF magnetic fields on the reward system. Secondly, we reported our studies during my postgraduate period. The studies assessed the activities of the orbitofrontal cortex (OFC) in rats during the process of food-related stimulus, and the effects of the ELF magnetic fields on spatial cognitive function in mice. In Experiment 1, we recorded EEG activity in the OFC in rats during the development of food reward and craving. In Experiment 2, the short- and long-term effects of 50 Hz and 25 Hz magnetic fields on spatial recognition memory in mice by using a two-trial recognition Y-maze that is based on the innate tendency of rodents to explore novel environments, in which no rewards are involved. Our results are as following: In Experiment 1, the EEG activity peaking in delta band (2-4 Hz) was significantly correlated with the stimulus in the food-related environment, increasing during food reward and decreasing during food craving when compared with that in the control environment; In Experiment 2, long-term exposure to 50 Hz fields reduced recognition of the novel arm. However, neither short- nor long-term exposure to magnetic fields affects the locomotor activity of mice in the Y-maze. In summary, the delta EEG activity in the OFC could be altered by the food reward, and still in this region the gamma activity has been found to correlate with opiate addiction. Thus, these studies suggested that the OFC may play differential effects during the process of drug addction and natural rewards. Additionally, the ELF magnetic fields impair spatial recognition memory in the Y-maze in mice depending on the field strength and/or duration of exposure. Our study demonstrates, for the first time, that long-term exposure to 50 Hz electromagnetic fields impairs spatial recognition memory in a task that does not involve reward. The ELF magnetic fields have been found to potentiate morphine-induced conditional place preferences in rats. Therefore, the ELF magnetic fields may take special biological effects on drug addiction. |
| 语种 | 中文 |
| 公开日期 | 2010-10-15 |
| 源URL | [http://159.226.149.42:8088/handle/152453/6279]  |
| 专题 | 昆明动物研究所_认知障碍病理学 |
| 推荐引用方式 GB/T 7714 | 付玉. 1.初级视觉皮层功能，GABA系统功能在衰老过程中的变化; 2.奖赏机制，极低频磁场的生物学效应研究[D]. 北京. 中国科学院研究生院. 2008. |
入库方式： OAI收割
来源：昆明动物研究所
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