机器人人工嗅觉系统设计

利用半导体气体传感器的交叉敏特性,将气体传感器阵列与神经网络相结合,构建了一个用于临场感机器人的人工嗅觉系统,用于气体的定性识别.自组织神经网络(SOM)将被测气体的多维特征信息映射到一个二维平面上,从而实现了对被测气体的识别分类.实验结果表明半导体阵列人工嗅觉系统可以提高气体传感器的选择性,用SOM神经网络构建人工嗅觉识别模型是完全可行的.     

人工嗅觉系统在卷烟内在客观评定中的应用展望

概述了人工嗅觉系统的研究历史与应用现状，详细介绍了人工嗅觉系统的基本原理，了基于神经网络的人工嗅觉系统在卷烟内在质量评定中的广阔应用前景。     

嗅觉受体研究进展

嗅觉在动物的生命过程中起到很重要的作用。许多动物在很大程度上依赖它们的嗅觉协助活动、获得食物、辨别敌人和其他危险。嗅觉在配偶的选择、母子识别及群体之间的信号交流中发挥着作用[1,2]。然而,气体是怎样通过鼻子传递到脑呢?机体又如何辨别不同的气味呢?大量的研究发现,这个过程是通过结合嗅觉受体(Olfactory receptor,OR)而起作用的。Lancet等研究表明,OR基因的缺失能引起特异性的嗅觉分辨力下降或缺失[3]。1 OR基因的分布、信号途径及其功能嗅觉受体基因属于G蛋白偶联受体超家族。1991年Buck和Axel首次在褐家鼠(Rattusnorvegi…     

嗅觉可视化技术在猪肉新鲜度检测中的应用

针对肉类快速检测的需求和人工嗅觉技术存在的检测范围窄、受环境温度影响大等缺陷,根据金属卟啉化合物与有机小分子气体反应后发生颜色变化的原理,介绍了人工嗅觉可视化技术在肉类检测中的应用,首先介绍了金属卟啉化合物的特性及气体可视化传感器阵列的制作过程,然后对嗅觉可视化系统的组成做了简要介绍.     

人工嗅觉技术在智能火灾探测中的应用研究

介绍了人工嗅觉模拟技术的原理，提出了一种利用神经网络和模糊系统理论设计智能建筑火灾报警系统的方法。     

通向嗅觉之路

鲜花的芬芳，臭鸡蛋的腐味，不同的气味让我们对物质有着或喜爱或厌恶的感受。人类的嗅觉虽然无法与有些动物媲美，但这也足以令我们受用无穷了。     

气味受体的研究进展

气味爱体是哺乳动物识别各种气味分子和启动嗅信号转导的关键蛋白。气味受体位于嗅感觉神经元树突的纤毛上，属于G蛋白耦联受体超家族成员，由多基因家族编码。人类气味受体基因分布在几乎全部的染色体上。一个基因编码一种受体，一种受体可和几种气味分子结合。嗅觉系统可能是以一种组合的方式处理和识别嗅觉信息的。     

基于嗅觉可视化技术的猪肉新鲜度检测

嗅觉可视化技术是使非可见物质成像(主要是气体成像)的一种无损检测新技术,属人工嗅觉模拟技术的一个新分支.使用卟啉和pH指示剂作为嗅觉可视化传感器阵列的气敏材料,检测猪肉中的优势致腐菌和新鲜度.将3种优势致腐菌(梭状芽孢杆菌、热死环丝菌、假单胞菌)分别接种至3组猪肉样本中,在3种温度(-16℃,4℃和20℃)条件下分别贮藏不同的时间后,采用扫描仪获取可视化传感器阵列与每个样本反应前后的图像信息;将阵列反应前后的颜色差值作为样本特征值,对不同的猪肉样本经不同贮藏时间后产生的挥发性气味,可视化传感器阵列显示其特定的颜色图像与其对应.结果表明,嗅觉可视化技术可以用于检测猪肉的优势致腐菌以及判断猪肉的新鲜度.     

嗅觉在母性行为中的作用

母性攻击行为和识别行为是构成母性行为的重要组成部分 ,嗅觉在其中起主要作用 .主要嗅觉系统和梨鼻系统在母性攻击行为、识别行为中的作用不同 ,其它感觉模式在这两种行为中起辅助作用 ,而且动物的后天经验会影响母性行为 .     

用嗅觉去感受世界--2004年诺贝尔生理学或医学奖成果简介

嗅觉系统对我们的生活非常重要,人类和其它哺乳动物利用嗅觉系统可以识别环境中巨大数量的化学物质。嗅觉是如何产生的？为解开这个难题,美国两位科学家阿克塞尔和巴克从编码气味受体的基因入手,发现了识别气味分子的受体,并且证明了嗅觉系统的组织方式,从而告诉世界我们是如何感受气味的。为表彰两人的贡献,Karolinska医学院诺贝尔奖评审委员会决定授予他们2004年诺贝尔生理学或医学奖。介绍了两位科学家是如何破解这个难题的。     

Genetic tracing reveals a stereotyped sensory map in the olfactory cortex.

The olfactory system translates myriad chemical structures into diverse odour perceptions. To gain insight into how this is accomplished, we prepared mice that coexpressed a transneuronal tracer with only one of about 1,000 different odorant receptors. The tracer travelled from nasal neurons expressing that receptor to the olfactory bulb and then to the olfactory cortex, allowing visualization of cortical neurons that receive input from a particular odorant receptor. These studies revealed a stereotyped sensory map in the olfactory cortex in which signals from a particular receptor are targeted to specific clusters of neurons. Inputs from different receptors overlap spatially and could be combined in single neurons, potentially allowing for an integration of the components of an odorant's combinatorial receptor code. Signals from the same receptor are targeted to multiple olfactory cortical areas, permitting the parallel, and perhaps differential, processing of inputs from a single receptor before delivery to the neocortex and limbic system.     

Innate versus learned odour processing in the mouse olfactory bulb

The mammalian olfactory system mediates various responses, including aversive behaviours to spoiled foods and fear responses to predator odours. In the olfactory bulb, each glomerulus represents a single species of odorant receptor. Because a single odorant can interact with several different receptor species, the odour information received in the olfactory epithelium is converted to a topographical map of multiple glomeruli activated in distinct areas in the olfactory bulb. To study how the odour map is interpreted in the brain, we generated mutant mice in which olfactory sensory neurons in a specific area of the olfactory epithelium are ablated by targeted expression of the diphtheria toxin gene. Here we show that, in dorsal-zone-depleted mice, the dorsal domain of the olfactory bulb was devoid of glomerular structures, although second-order neurons were present in the vacant areas. The mutant mice lacked innate responses to aversive odorants, even though they were capable of detecting them and could be conditioned for aversion with the remaining glomeruli. These results indicate that, in mice, aversive information is received in the olfactory bulb by separate sets of glomeruli, those dedicated for innate and those for learned responses.     

Cortical representations of olfactory input by trans-synaptic tracing

In the mouse, each class of olfactory receptor neurons expressing a given odorant receptor has convergent axonal projections to two specific glomeruli in the olfactory bulb, thereby creating an odour map. However, it is unclear how this map is represented in the olfactory cortex. Here we combine rabies-virus-dependent retrograde mono-trans-synaptic labelling with genetics to control the location, number and type of 'starter' cortical neurons, from which we trace their presynaptic neurons. We find that individual cortical neurons receive input from multiple mitral cells representing broadly distributed glomeruli. Different cortical areas represent the olfactory bulb input differently. For example, the cortical amygdala preferentially receives dorsal olfactory bulb input, whereas the piriform cortex samples the whole olfactory bulb without obvious bias. These differences probably reflect different functions of these cortical areas in mediating innate odour preference or associative memory. The trans-synaptic labelling method described here should be widely applicable to mapping connections throughout the mouse nervous system.     

C. elegans odour discrimination requires asymmetric diversity in olfactory neurons

Caenorhabditis elegans senses at least five attractive odours with a single pair of olfactory neurons, AWC, but can distinguish among these odours in behavioural assays. The two AWC neurons are structurally and functionally similar, but the G-protein-coupled receptor STR-2 is randomly expressed in either the left or the right AWC neuron, never in both. Here we describe the isolation of a mutant, ky542, with specific defects in odour discrimination and odour chemotaxis. ky542 is an allele of nsy-1, a neuronal symmetry, or Nsy, mutant in which STR-2 is expressed in both AWC neurons. Other Nsy mutants exhibit discrimination and olfactory defects like those of nsy-1 mutants. Laser ablation of the AWC neuron that does not express STR-2 (AWCOFF) recapitulates the behavioural phenotype of Nsy mutants, whereas laser ablation of the STR-2-expressing AWC neuron (AWCON) causes different chemotaxis defects. We propose that odour discrimination can be achieved by segregating the detection of different odours into distinct olfactory neurons or into unique combinations of olfactory neurons.     

Lateral presynaptic inhibition mediates gain control in an olfactory circuit

Olfactory signals are transduced by a large family of odorant receptor proteins, each of which corresponds to a unique glomerulus in the first olfactory relay of the brain. Crosstalk between glomeruli has been proposed to be important in olfactory processing, but it is not clear how these interactions shape the odour responses of second-order neurons. In the Drosophila antennal lobe (a region analogous to the vertebrate olfactory bulb), we selectively removed most interglomerular input to genetically identified second-order olfactory neurons. Here we show that this broadens the odour tuning of these neurons, implying that interglomerular inhibition dominates over interglomerular excitation. The strength of this inhibitory signal scales with total feedforward input to the entire antennal lobe, and has similar tuning in different glomeruli. A substantial portion of this interglomerular inhibition acts at a presynaptic locus, and our results imply that this is mediated by both ionotropic and metabotropic receptors on the same nerve terminal.     

黑鲷化学感觉发育和摄食关系

研究了黑鲷（Ｓｐａｒｕｓｍａｃｒｏｃｅｐｈａｌｕｓ）仔、稚、幼鱼嗅觉和味觉器官的基本结构及嗅觉、味觉与摄食的关系，初孵仔鱼的嗅囊很小、很浅，细胞没有分化。５ｄ的嗅囊细胞开始分化，２４ｄ嗅囊分化完毕，嗅觉开始功能化，参与摄食反应。初孵仔鱼味蕾没分化，５ｄ的仔鱼味蕾分化形成，参与摄食反应。随发育的进行，先后从口咽腔、头部、躯干、尾部、鳍等处依次出现味蕾。嗅觉和味觉是鱼类的化学感觉，嗅觉可以对远、近距离的食物发生反应，而味觉只能对接触的或几乎接触的食物发生反应。化学感觉对摄食的作用是对黑暗条件下视觉摄食的补充。     

Discrimination of signal oscillations in the in vitro olfactory bulb with microelectrode array

The aim of the present study was to investigate the electrophysiological characteristics of the different layers of the olfactory bulb (OB). We used an in vitro OB slice coupled onto a microelectrode array (MEA) for simultaneous detection of spontaneous activities of OB neurons at different sites. Different frequency oscillations dominated the different layers of the OB slice, and the gamma frequency oscillations mainly appeared in the glomerular layer. The waves consisted of negative, positive, and bidirectional spikes, and were distributed at the different layers of the OB slice. Thus, combination of the OB slice with MEA is a useful technique for identifying signal oscillations by multi-site synchronous measurement, and will allow further studies on olfactory information coding and processing function.     

小菜蛾对蔬菜气味的定向行为

采用“Y”型管嗅觉仪 ,在实验室条件下 ,对十字花科蔬菜 -小菜蛾 -小菜蛾绒茧蜂系统中 ,害虫和寄生蜂对挥发物的定向行为进行了初步的研究。结果表明蔬菜的挥发性气味对小菜蛾有明显的引诱作用 ,在反应强度上 ,雌蛾明显高于雄蛾 ,且不同的蔬菜引诱效果之间也存在差异。触角切除实验证明了 ,在小菜蛾成虫感受植物挥发性气味的过程中触角起着主要作用     

The progress of olfactory transduction and biomimetic olfactory-based biosensors

Olfaction is a very important sensation for all animals. Recently great progress has been made in the research of olfactory transduction. Especially the novel finding of the gene superfamily encoding olfactory receptors has led to rapid advances in olfactory transduction. These advances also promoted the research of biomimetic olfactory-based biosensors and some obvious achievements have been obtained due to their potential commercial prospects and promising industrial applications. This paper briefly introduces the biological basis of olfaction, summarizes the progress of olfactory signal transduction in the olfactory neuron, the olfactory bulb and the olfactory cortex, outlines the latest devel- opments and applications of biomimetic olfactory-based biosensors. Finally, the olfactory biosensor based on light addressable potentiometric sensor (LAPS) is addressed in detail based on our recent work and the research trends of olfactory biosensors in future are discussed.     

嗅觉神经系统的电位发放

利用描述抑制结构的WLC模型,数值分析嗅觉神经系统各个神经元的电位发放,得到嗅觉神经系统中球周细胞层、嗅球、僧帽细胞层、颗粒细胞层、前嗅核和前梨状皮层内各个神经元的电位发放,模拟了Freeman嗅觉系统各K系列模型的电位发放模式,数值说明僧帽细胞具有丰富的发放形式,神经元之间的具有两种信号传递模式,数值结果和嗅觉实验现象相吻合.