清醒小鼠嗅皮层细胞对气味反应的研究

发布时间：2019-05-13 20:16

【摘要】：哺乳动物的嗅皮层接受来之嗅球的信息,并被认为是形成气味感知的重要部位,目前还不清楚嗅皮层是如何编码和表征气味信息的,也不知道其是否具有类似其他感觉皮层对刺激信息的时间和空间编码规律。另外,由于目前大部分的研究结论都是基于麻醉动物上的实验得到的,麻醉剂的影响产生一些难以预知的干扰,引起实验结果的不确定。本文通过对清醒动物的嗅皮层神经元进行细胞外电生理记录,研究了嗅皮层中单个神经元对气味是如何反应的。记录完成后标记出神经元,并通过所标记细胞的形态,电生理特性,以及神经递质类型把细胞分为主神经元以及不同类型的中间神经元。本文发现嗅皮层神经元对气味信息有着非常不同的选择性和反应调谐特性。在嗅皮层上,大约有1/4的主神经元可以被分子结构不同的气味广泛激活,有1/4的主神经元被分子结构不同的气味广泛抑制,而其他约1/2的主神经元对实验中用到的大部分气味没有任何反应,有非常高的气味选择性。作者还发现GABA神经元对测试气味选择性较低,且很少会被气味抑制。其他非GABA的中间神经元则被许多气味强烈抑制。总的来说,这些结果显示在清醒小鼠的嗅皮层上气味信息是被众多气味选择性不同的神经元表征和编码的,这些反应调谐曲线不同的神经元也许在气味感知和编码中发挥着不同的作用。本文通过比较嗅皮层邻近细胞对气味的反应情况,发现当一个细胞对测试气味有某种反应特性,与之距离小于50μm的细胞很可能具有类似的反应特征,这暗示着嗅皮层对气味的编码并非完全没有空间规律。最后,本文研究了动物生理与行为状态对嗅皮层细胞活动的影响,实验发现动物的运动状态与嗅皮层细胞的自发活动有紧密关联,即快速运动状态下嗅皮层细胞基本不发放,当动物停止运动和静止时,细胞恢复自发放电。这暗示嗅皮层细胞对气味反应也可能与动物的行为状态有关,提示我们在不同的生理状态下,嗅皮层细胞对气味信息的处理和编码有可能不同。
[Abstract]:The olfactory cortex of mammals receives information from the olfactory bulb and is considered to be an important part of odor perception. It is not clear how the olfactory cortex encodes and represents odor information. It is also not known whether it has a temporal and spatial coding law similar to that of other sensory cortex on stimulation information. In addition, because most of the current research conclusions are based on the experiments in anesthetized animals, the effects of anesthetics have some unpredictable interference, resulting in uncertainty of the experimental results. In this paper, the extracellular electrophysiological records of olfactory cortical neurons in awake animals were carried out to study how a single neuron in the olfactory cortex responds to odour. After recording, the neurons were marked, and the cells were divided into main neurons and different types of intermediate neurons according to the morphology, electrophysiological characteristics and neurotransmitter types of the labeled cells. In this paper, it is found that olfactory cortical neurons have very different selectivity and response tuning characteristics to odor information. In the olfactory cortex, about 1 脳 4 of the main neurons can be widely activated by odors with different molecular structures, and 1 / 4 of the main neurons can be widely suppressed by different odors of different molecular structures. The other main neurons, about 1 脳 2, had no response to most of the odors used in the experiment and had very high odour selectivity. The authors also found that GABA neurons were less selective to test odors and were rarely suppressed by odors. Other non-GABA intermediate neurons were strongly suppressed by many odors. In general, these results show that odour information on the olfactory cortex of awake mice is characterized and encoded by many neurons with different odors selectivity. These neurons with different response tuning curves may play different roles in odor perception and coding. In this paper, by comparing the response of cells adjacent to olfactory skin layer to odour, it is found that when a cell has a certain response characteristic to the tested odor, the cells whose distance is less than 50 渭 m are likely to have similar response characteristics. This suggests that the coding of odors in the olfactory cortex is not completely spatial. Finally, the effects of physiological and behavioral states on the activity of olfactory cortical cells were studied. It was found that the motor state of animals was closely related to the spontaneous activity of olfactory cortical cells, that is, the olfactory cortical cells were basically not released under the condition of rapid movement. When the animal stops moving and resting, the cell resumes spontaneous discharge. This suggests that the response of olfactory cortical cells to odour may also be related to the behavior of animals, suggesting that the processing and coding of odor information by olfactory cortical cells may be different under different physiological conditions.
【学位授予单位】：华中科技大学
【学位级别】：博士
【学位授予年份】：2011
【分类号】：R339.1

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