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Coureaud G, Thomas-Danguin T, Sandoz JC, Wilson DA. Biological constraints on configural odour mixture perception. J Exp Biol 2022; 225:274695. [PMID: 35285471 PMCID: PMC8996812 DOI: 10.1242/jeb.242274] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Animals, including humans, detect odours and use this information to behave efficiently in the environment. Frequently, odours consist of complex mixtures of odorants rather than single odorants, and mixtures are often perceived as configural wholes, i.e. as odour objects (e.g. food, partners). The biological rules governing this 'configural perception' (as opposed to the elemental perception of mixtures through their components) remain weakly understood. Here, we first review examples of configural mixture processing in diverse species involving species-specific biological signals. Then, we present the original hypothesis that at least certain mixtures can be processed configurally across species. Indeed, experiments conducted in human adults, newborn rabbits and, more recently, in rodents and honeybees show that these species process some mixtures in a remarkably similar fashion. Strikingly, a mixture AB (A, ethyl isobutyrate; B, ethyl maltol) induces configural processing in humans, who perceive a mixture odour quality (pineapple) distinct from the component qualities (A, strawberry; B, caramel). The same mixture is weakly configurally processed in rabbit neonates, which perceive a particular odour for the mixture in addition to the component odours. Mice and honeybees also perceive the AB mixture configurally, as they respond differently to the mixture compared with its components. Based on these results and others, including neurophysiological approaches, we propose that certain mixtures are convergently perceived across various species of vertebrates/invertebrates, possibly as a result of a similar anatomical organization of their olfactory systems and the common necessity to simplify the environment's chemical complexity in order to display adaptive behaviours.
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Affiliation(s)
- Gérard Coureaud
- Centre de Recherche en Neurosciences de Lyon, Team Sensory Neuroethology (ENES), CNRS/INSERM/UCBL1/UJM, 69500 Lyon, France
| | - Thierry Thomas-Danguin
- Centre des Sciences du Goût et de l'Alimentation, Team Flavor, Food Oral Processing and Perception, INRAE, CNRS, Institut Agro Dijon, Université Bourgogne Franche-Comté, 21000 Dijon, France
| | - Jean-Christophe Sandoz
- Evolution, Genomes, Behavior and Ecology, CNRS, Université Paris-Saclay, IRD, 91190 Gif-sur-Yvette, France
| | - Donald A Wilson
- Department of Child & Adolescent Psychiatry, New York University Langone School of Medicine and Nathan S. Kline Institute for Psychiatric Research, New York, NY 10016, USA
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2
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Chen YC, Mishra D, Gläß S, Gerber B. Behavioral Evidence for Enhanced Processing of the Minor Component of Binary Odor Mixtures in Larval Drosophila. Front Psychol 2017; 8:1923. [PMID: 29163299 PMCID: PMC5672140 DOI: 10.3389/fpsyg.2017.01923] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 10/17/2017] [Indexed: 02/02/2023] Open
Abstract
A fundamental problem in deciding between mutually exclusive options is that the decision needs to be categorical although the properties of the options often differ but in grade. We developed an experimental handle to study this aspect of behavior organization. Larval Drosophila were trained such that in one set of animals odor A was rewarded, but odor B was not (A+/B), whereas a second set of animals was trained reciprocally (A/B+). We then measured the preference of the larvae either for A, or for B, or for "morphed" mixtures of A and B, that is for mixtures differing in the ratio of the two components. As expected, the larvae showed higher preference when only the previously rewarded odor was presented than when only the previously unrewarded odor was presented. For mixtures of A and B that differed in the ratio of the two components, the major component dominated preference behavior-but it dominated less than expected from a linear relationship between mixture ratio and preference behavior. This suggests that a minor component can have an enhanced impact in a mixture, relative to such a linear expectation. The current paradigm may prove useful in understanding how nervous systems generate discrete outputs in the face of inputs that differ only gradually.
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Affiliation(s)
- Yi-Chun Chen
- Abteilung Genetik von Lernen und Gedächtnis, Leibniz Institut für Neurobiologie, Magdeburg, Germany.,Genetik und Neurobiologie, Biozentrum, Universität Würzburg, Würzburg, Germany
| | - Dushyant Mishra
- Genetik und Neurobiologie, Biozentrum, Universität Würzburg, Würzburg, Germany
| | - Sebastian Gläß
- Abteilung Genetik von Lernen und Gedächtnis, Leibniz Institut für Neurobiologie, Magdeburg, Germany
| | - Bertram Gerber
- Abteilung Genetik von Lernen und Gedächtnis, Leibniz Institut für Neurobiologie, Magdeburg, Germany.,Genetik und Neurobiologie, Biozentrum, Universität Würzburg, Würzburg, Germany.,Center for Behavioral and Brain Sciences, Magdeburg, Germany.,Institut für Biologie, Universität Magdeburg, Magdeburg, Germany
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3
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Synergism and Combinatorial Coding for Binary Odor Mixture Perception in Drosophila. eNeuro 2016; 3:eN-NWR-0056-14. [PMID: 27588303 PMCID: PMC4994066 DOI: 10.1523/eneuro.0056-14.2016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Revised: 07/25/2016] [Accepted: 08/03/2016] [Indexed: 11/21/2022] Open
Abstract
Most odors in the natural environment are mixtures of several compounds. Olfactory receptors housed in the olfactory sensory neurons detect these odors and transmit the information to the brain, leading to decision-making. But whether the olfactory system detects the ingredients of a mixture separately or treats mixtures as different entities is not well understood. Using Drosophila melanogaster as a model system, we have demonstrated that fruit flies perceive binary odor mixtures in a manner that is heavily dependent on both the proportion and the degree of dilution of the components, suggesting a combinatorial coding at the peripheral level. This coding strategy appears to be receptor specific and is independent of interneuronal interactions.
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Chen YC, Gerber B. Generalization and discrimination tasks yield concordant measures of perceived distance between odours and their binary mixtures in larval Drosophila. ACTA ACUST UNITED AC 2015; 217:2071-7. [PMID: 24920835 PMCID: PMC4191342 DOI: 10.1242/jeb.100966] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Similarity between odours is notoriously difficult to measure. Widely used behavioural approaches in insect olfaction research are cross-adaptation, masking, as well as associative tasks based on olfactory learning and the subsequent testing for how specific the established memory is. A concern with such memory-based approaches is that the learning process required to establish an odour memory may alter the way the odour is processed, such that measures of perception taken at the test are distorted. The present study was therefore designed to see whether behavioural judgements of perceptual distance are different for two different memory-based tasks, namely generalization and discrimination. We used odour–reward learning in larval Drosophila as a study case. In order to challenge the larvae's olfactory system, we chose to work with binary mixtures and their elements (1-octanol, n-amyl acetate, 3-octanol, benzaldehyde and hexyl acetate). We determined the perceptual distance between each mixture and its elements, first in a generalization task, and then in a discrimination task. It turns out that scores of perceptual distance are correlated between both tasks. A re-analysis of published studies looking at element-to-element perceptual distances in larval reward learning and in adult punishment learning confirms this result. We therefore suggest that across a given set of olfactory stimuli, associative training does not grossly alter the pattern of perceptual distances.
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Affiliation(s)
- Yi-chun Chen
- Universität Würzburg, Biozentrum, Lehrstuhl für Genetik und Neurobiologie, 97074 Würzburg, Germany
| | - Bertram Gerber
- Universität Würzburg, Biozentrum, Lehrstuhl für Genetik und Neurobiologie, 97074 Würzburg, Germany Otto von Guericke Universität Magdeburg, Institut für Biologie, Verhaltensgenetik, 39106 Magdeburg, Germany Center for Behavioral Brain Science (CBBS), 39106 Magdeburg, Germany Leibniz Institut für Neurobiologie (LIN), Abteilung Genetik von Lernen und Gedächtnis, 39118 Magdeburg, Germany
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5
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Thomas-Danguin T, Sinding C, Romagny S, El Mountassir F, Atanasova B, Le Berre E, Le Bon AM, Coureaud G. The perception of odor objects in everyday life: a review on the processing of odor mixtures. Front Psychol 2014; 5:504. [PMID: 24917831 PMCID: PMC4040494 DOI: 10.3389/fpsyg.2014.00504] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Accepted: 05/08/2014] [Indexed: 11/13/2022] Open
Abstract
Smelling monomolecular odors hardly ever occurs in everyday life, and the daily functioning of the sense of smell relies primarily on the processing of complex mixtures of volatiles that are present in the environment (e.g., emanating from food or conspecifics). Such processing allows for the instantaneous recognition and categorization of smells and also for the discrimination of odors among others to extract relevant information and to adapt efficiently in different contexts. The neurophysiological mechanisms underpinning this highly efficient analysis of complex mixtures of odorants is beginning to be unraveled and support the idea that olfaction, as vision and audition, relies on odor-objects encoding. This configural processing of odor mixtures, which is empirically subject to important applications in our societies (e.g., the art of perfumers, flavorists, and wine makers), has been scientifically studied only during the last decades. This processing depends on many individual factors, among which are the developmental stage, lifestyle, physiological and mood state, and cognitive skills; this processing also presents striking similarities between species. The present review gathers the recent findings, as observed in animals, healthy subjects, and/or individuals with affective disorders, supporting the perception of complex odor stimuli as odor objects. It also discusses peripheral to central processing, and cognitive and behavioral significance. Finally, this review highlights that the study of odor mixtures is an original window allowing for the investigation of daily olfaction and emphasizes the need for knowledge about the underlying biological processes, which appear to be crucial for our representation and adaptation to the chemical environment.
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Affiliation(s)
- Thierry Thomas-Danguin
- Centre des Sciences du Goût et de l'Alimentation, CNRS UMR6265, INRA UMR1324, Université de Bourgogne Dijon, France
| | - Charlotte Sinding
- Smell and Taste Clinic, Department of Otorhinolaryngoly TU Dresden, Dresden, Germany
| | - Sébastien Romagny
- Centre des Sciences du Goût et de l'Alimentation, CNRS UMR6265, INRA UMR1324, Université de Bourgogne Dijon, France
| | - Fouzia El Mountassir
- Centre des Sciences du Goût et de l'Alimentation, CNRS UMR6265, INRA UMR1324, Université de Bourgogne Dijon, France
| | | | | | - Anne-Marie Le Bon
- Centre des Sciences du Goût et de l'Alimentation, CNRS UMR6265, INRA UMR1324, Université de Bourgogne Dijon, France
| | - Gérard Coureaud
- Centre des Sciences du Goût et de l'Alimentation, CNRS UMR6265, INRA UMR1324, Université de Bourgogne Dijon, France
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Barth J, Dipt S, Pech U, Hermann M, Riemensperger T, Fiala A. Differential associative training enhances olfactory acuity in Drosophila melanogaster. J Neurosci 2014; 34:1819-37. [PMID: 24478363 PMCID: PMC6827587 DOI: 10.1523/jneurosci.2598-13.2014] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Revised: 12/13/2013] [Accepted: 12/17/2013] [Indexed: 11/21/2022] Open
Abstract
Training can improve the ability to discriminate between similar, confusable stimuli, including odors. One possibility of enhancing behaviorally expressed discrimination (i.e., sensory acuity) relies on differential associative learning, during which animals are forced to detect the differences between similar stimuli. Drosophila represents a key model organism for analyzing neuronal mechanisms underlying both odor processing and olfactory learning. However, the ability of flies to enhance fine discrimination between similar odors through differential associative learning has not been analyzed in detail. We performed associative conditioning experiments using chemically similar odorants that we show to evoke overlapping neuronal activity in the fly's antennal lobes and highly correlated activity in mushroom body lobes. We compared the animals' performance in discriminating between these odors after subjecting them to one of two types of training: either absolute conditioning, in which only one odor is reinforced, or differential conditioning, in which one odor is reinforced and a second odor is explicitly not reinforced. First, we show that differential conditioning decreases behavioral generalization of similar odorants in a choice situation. Second, we demonstrate that this learned enhancement in olfactory acuity relies on both conditioned excitation and conditioned inhibition. Third, inhibitory local interneurons in the antennal lobes are shown to be required for behavioral fine discrimination between the two similar odors. Fourth, differential, but not absolute, training causes decorrelation of odor representations in the mushroom body. In conclusion, differential training with similar odors ultimately induces a behaviorally expressed contrast enhancement between the two similar stimuli that facilitates fine discrimination.
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Affiliation(s)
- Jonas Barth
- Georg-August-University Göttingen, Johann-Friedrich-Blumenbach-Institute for Zoology and Anthropology, Molecular Neurobiology of Behavior, 37077 Göttingen, Germany
| | - Shubham Dipt
- Georg-August-University Göttingen, Johann-Friedrich-Blumenbach-Institute for Zoology and Anthropology, Molecular Neurobiology of Behavior, 37077 Göttingen, Germany
| | - Ulrike Pech
- Georg-August-University Göttingen, Johann-Friedrich-Blumenbach-Institute for Zoology and Anthropology, Molecular Neurobiology of Behavior, 37077 Göttingen, Germany
| | - Moritz Hermann
- Georg-August-University Göttingen, Johann-Friedrich-Blumenbach-Institute for Zoology and Anthropology, Molecular Neurobiology of Behavior, 37077 Göttingen, Germany
| | - Thomas Riemensperger
- Georg-August-University Göttingen, Johann-Friedrich-Blumenbach-Institute for Zoology and Anthropology, Molecular Neurobiology of Behavior, 37077 Göttingen, Germany
| | - André Fiala
- Georg-August-University Göttingen, Johann-Friedrich-Blumenbach-Institute for Zoology and Anthropology, Molecular Neurobiology of Behavior, 37077 Göttingen, Germany
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Clifford MR, Riffell JA. Mixture and odorant processing in the olfactory systems of insects: a comparative perspective. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2013; 199:911-28. [PMID: 23660810 DOI: 10.1007/s00359-013-0818-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Revised: 04/06/2013] [Accepted: 04/08/2013] [Indexed: 01/18/2023]
Abstract
Natural olfactory stimuli are often complex mixtures of volatiles, of which the identities and ratios of constituents are important for odor-mediated behaviors. Despite this importance, the mechanism by which the olfactory system processes this complex information remains an area of active study. In this review, we describe recent progress in how odorants and mixtures are processed in the brain of insects. We use a comparative approach toward contrasting olfactory coding and the behavioral efficacy of mixtures in different insect species, and organize these topics around four sections: (1) Examples of the behavioral efficacy of odor mixtures and the olfactory environment; (2) mixture processing in the periphery; (3) mixture coding in the antennal lobe; and (4) evolutionary implications and adaptations for olfactory processing. We also include pertinent background information about the processing of individual odorants and comparative differences in wiring and anatomy, as these topics have been richly investigated and inform the processing of mixtures in the insect olfactory system. Finally, we describe exciting studies that have begun to elucidate the role of the processing of complex olfactory information in evolution and speciation.
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Affiliation(s)
- Marie R Clifford
- Department of Biology, University of Washington, Seattle, WA, 98195, USA,
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8
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‘Decision Making’ in Larval Drosophila. ACTA ACUST UNITED AC 2013. [DOI: 10.1016/b978-0-12-415823-8.00005-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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9
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Szyszka P, Stierle JS, Biergans S, Galizia CG. The speed of smell: odor-object segregation within milliseconds. PLoS One 2012; 7:e36096. [PMID: 22558344 PMCID: PMC3338635 DOI: 10.1371/journal.pone.0036096] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Accepted: 03/28/2012] [Indexed: 11/29/2022] Open
Abstract
Segregating objects from background, and determining which of many concurrent stimuli belong to the same object, remains one of the most challenging unsolved problems both in neuroscience and in technical applications. While this phenomenon has been investigated in depth in vision and audition it has hardly been investigated in olfaction. We found that for honeybees a 6-ms temporal difference in stimulus coherence is sufficient for odor-object segregation, showing that the temporal resolution of the olfactory system is much faster than previously thought.
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Affiliation(s)
- Paul Szyszka
- Department of Biology, University of Konstanz, Konstanz, Germany.
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Sinding C, Thomas-Danguin T, Crepeaux G, Schaal B, Coureaud G. Experience influences elemental and configural perception of certain binary odour mixtures in newborn rabbits. J Exp Biol 2011; 214:4171-8. [DOI: 10.1242/jeb.063610] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
Elemental and configural olfactory perception allows interaction with the environment from very early in life. To evaluate how newborn rabbits can extract and respond to information from the highly complex chemical surroundings, and how experience acts on this sensory, cognitive and behavioural capability, we ran a study in four steps including a total of eight experiments. We mainly used a binary AB mixture comprising ethyl isobutyrate (component A) and ethyl maltol (component B), previously shown as a bearer of blending properties; in rabbit pups (as in human adults), the mixture elicits a weak configural perception, i.e. the perception of a configural odour different from the odours of the components. First, a repeated exposure to one component of AB led to a more elemental perception of this mixture; conversely, a repeated exposure to AB facilitated its configural processing. Second, similar impact of experience did not appear with a non-blending AC mixture (ethyl isobutyrate-guaïacol). Third, repeated exposure to AB impacted not only the perception of AB, but also and in the same way the perception of the AC mixture sharing one component, and reciprocally. However, facilitation to perceive one mixture in one mode (configural/elemental) was not generalized to a mixture sharing no components with the experienced mixture [AB versus DE (damascenone and vanillin)]. Thus, experience contributes to the neonatal perception of odour mixtures and adds plasticity to the perceptual system. However, this impact remains dependent on the chemical composition of the mixtures.
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Affiliation(s)
- Charlotte Sinding
- Centre des Sciences du Goût et de l'Alimentation, UMR 6265 CNRS, UMR 1324 INRA, Université de Bourgogne, Agrosup Dijon, 9E Boulevard Jeanne d'Arc, 21000 Dijon, France
| | - Thierry Thomas-Danguin
- Centre des Sciences du Goût et de l'Alimentation, UMR 6265 CNRS, UMR 1324 INRA, Université de Bourgogne, Agrosup Dijon, 9E Boulevard Jeanne d'Arc, 21000 Dijon, France
| | - Guillemette Crepeaux
- Centre des Sciences du Goût et de l'Alimentation, UMR 6265 CNRS, UMR 1324 INRA, Université de Bourgogne, Agrosup Dijon, 9E Boulevard Jeanne d'Arc, 21000 Dijon, France
| | - Benoist Schaal
- Centre des Sciences du Goût et de l'Alimentation, UMR 6265 CNRS, UMR 1324 INRA, Université de Bourgogne, Agrosup Dijon, 9E Boulevard Jeanne d'Arc, 21000 Dijon, France
| | - Gérard Coureaud
- Centre des Sciences du Goût et de l'Alimentation, UMR 6265 CNRS, UMR 1324 INRA, Université de Bourgogne, Agrosup Dijon, 9E Boulevard Jeanne d'Arc, 21000 Dijon, France
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