Configurational and nonconfigurational interactions between odorants in binary mixtures.

Studies on odor mixture perception suggest that although odor components can often be identified in mixtures, mixtures can also give rise to novel perceptual qualities that are not present in the components. Using an olfactory habituation task, the authors evaluated how the perceptual similarity between components in a mixture affects the perceptual quality of the mixture itself. Rats perceived binary mixtures composed of similar components as different from their 2 components, whereas binary mixtures composed of dissimilar components were perceived as very similar to their components. Results show that for both types of mixtures, pretraining to Component A reduces subsequent learning about Component B in rats trained in the presence of A. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A New Method for Comparing Orthonasal and Retronasal Olfaction.

Odors seem to be perceived differently when presented ortho- or retronasally. In this study, stimuli of controlled concentration and duration were applied in either the anterior nasal cavity or epipharynx by means of air-dilution olfactometry. Stimulus concentration was monitored in the olfactory cleft. In Experiment 1, odor thresholds to a food (chocolate) and a nonfood (lavender) odor were lower for orthonasal, compared with retronasal, stimulation. In Experiment 2, intensity ratings to suprathreshold odor concentrations were significantly higher for orthonasal than for retronasal stimulation with hydro- hydrogen sulfide, but not phenyl ethyl alcohol. Accordingly, amplitudes and latencies of olfactory event-related gen potentials to retronasal stimuli were found to be smaller and prolonged, respectively. This indicates differential processing of olfactory stimuli presented through the retronasal or orthonasal routes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Olfactory aposematism

Visual and acoustic cues may serve as aposematic signals that warn predators of poisonous foods. Olfactory aposematism, the use of innocuous odors as warning signals for toxic foods, is another possible means of alerting an animal that a potential food item is unpalatable. Although it has been suggested that olfactory aposematism might be the principle mode of warning utilized by plants in their defense against herbivores, experimental evidence is lacking. This study demonstrates that the opossum,Didelphis virginiana, can utilize an innocuous volatile compound found naturally in a mushroom as a warning signal for a delayed illness caused by mushroom toxin. This supports the contention that characteristic odors of toxic plants may serve a warning function, protecting herbivores from being poisoned and plants from being consumed.     

Airborne differences in odors emitted byRattus norvegicus in response to reward and nonreward

To test the hypothesis that rats (Rattus norvegicus) emit airborne, differential odors in response to reward and nonreward, donor rats received random sequences of rewarded and nonrewarded placements in small compartments and an airstream transported odors from these compartments to test rats in a separate chamber. When donors remained in the compartments during, or were removed just prior to, air transport, test rats utilized transported odors as discriminative cues signaling their own reward and nonreward for a lever-press response. When the airstream was passed through a clean compartment containing paper flooring extracted from donor compartments, test rats were not able to discriminate. Test trials to assess for control by food odors suggest that donor-produced odors, rather than food odors per se, provided the discriminative signals for test rats. Results confirm the existence of somewhat volatile, although apparently stable, odors emitted in response to reward and nonreward, and implicate a differential in amount and/or type of odor produced by donors to these two events as the source of discriminative control.     

基于移动机器人的主动嗅觉技术研究

使用移动机器人来定位气味源已经成为一个研究热点,机器人主动嗅觉是指使用机器人自主发现并跟踪烟羽,最终确定气味源所在位置的技术。本文对当前主动嗅觉技术进行概述,并根据生物嗅觉行为介绍一种气味源定位算法,这种算法不依赖某一点气味浓度值,仅依靠气味浓度变化率就可找到气味源。并在高斯模型下对烟羽分布模型进行仿真。     

Olfactory coding in the perception of semiochemicals

Information processing in the olfactory pathway underlying the perception of semiochemicals by insects is discussed. Both the chemical message for mates and the message for food consist of blends of chemicals. Olfactory receptors in an insect species are tuned to the detection of those compounds which comprise such chemical messages for that species. The classification of receptors as specialists or generalists coincides with two concepts of information processing, i.e., labeled lines and across-fiber patterns, respectively. The olfactory code coming from antennal receptors inPieris brassicae larvae is a combination of labeled lines and across-fiber patterning. When antennae of adult Colorado potato beetles,Leptinotarsa decemlineata, are stimulated by binary mixtures of leaf odor components, the pattern of neural activities in the olfactory receptors shows some separation into two channels, quantitative versus qualitative detection. The separation is complete in the antennal lobe of this beetle.Presented at the Symposium on Insect Chemical Communications: Unifying Concepts. ACS 194th National Meeting, New Orleans, Louisiana, August 31, 1987.     

Sex-identifying urine and molt signals in lobster (Homarus americanus)

During courtship, premolt female lobsters,Homarus americanus, choose a male and initiate a pair bond by repeated approaches to his shelter. The male allows such a female to share his shelter for about one week. This knowledge formed the basis to search for quantitative evidence for lobster sex pheromone(s) used in courtship: male cues to allow premolt females to identify a preferred male, and female cues to allow males to identify a premolt mature female. In each of four 1500-liter naturalistic aquaria, the behavioral responses of one female and two male lobsters to male and female lobster urine (0.5 ml) and body odor (20 ml) stimuli were observed. These stimuli were injected once or twice per day into a continuously flowing delivery tube attached to lobster shelters. Habituation to stimulus introduction—a serious problem in earlier experiments—was apparently avoided in the more natural social and physical environment we employed in these experiments. We demonstrated that male and female molt body odors contain different chemical substances: females responded to male molt body odor and males responded to female molt body odor but not vice versa. In general, male and female intermolt urine caused strong responses; however, females responded only weakly to male urine. This suggests that male and female urine are chemically different. Female urine and molt body odor caused a typically male high-on-legs response. These results show that molt body odors and intermolt urine contain sex-specific substances, which may be used in lobster courtship as well as other social interactions.     

响应曲面法优化河蚬发酵去腥工艺

采用生物发酵法对河蚬进行去腥处理,通过单因素试验研究酵母用量、发酵温度和发酵时间对去腥效果的影响,再运用响应曲面试验设计进行优化试验,确定最佳发酵去腥工艺条件。其最佳工艺条件为：以lOOg河蚬计,酵母2g、发酵温度36℃、发酵时间2h。     

基于金属氧化物气体传感器的气味罗盘的实验分析研究

设计一种由TGS2620金属氧化物气体传感器构建的气味罗盘系统。研制了气味罗盘的信号采样系统及辅助电路。在点气源及平流环境下对该系统进行了360°静态气源定位实验,提取传感器阻值响应比为特征量,并论证了该特征量与罗盘偏转角度α的对应关系。实验表明气味罗盘对相差30°方向的气源据有较大的响应差,以响应比值为特征量进行分析能够排除同类型传感器个体差异对分析结果的影响。     

Opposing Effects of D? and D? Receptor Activation on Odor Discrimination Learning.

Dopaminergic modulation of cortical activity has been implicated in the formation of reward associations. There is abundant evidence for dopaminergic effects on olfactory processing. Using an olfactory discrimination task, the authors show that D? and D? dopamine receptors can regulate rats' olfactory discrimination capacities and that the effects of receptor activation functionally oppose one another. Injection of either the D? agonist SKF 38393 (10 mg/kg) or the D? antagonist spiperone (0.62 mg/kg) facilitated the discrimination of similar odorants but had no effect on the discrimination of dissimilar odorants, whereas both the D, antagonist SCH 23390 (0.025 mg/kg) and the D? agonist quinpirole (0.2 mg/kg) significantly impaired rats' ability to discriminate similar and dissimilar odorants. (PsycINFO Database Record (c) 2010 APA, all rights reserved)