1
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Szyszka P, Emonet T, Edwards TL. Extracting spatial information from temporal odor patterns: insights from insects. CURRENT OPINION IN INSECT SCIENCE 2023; 59:101082. [PMID: 37419251 PMCID: PMC10878403 DOI: 10.1016/j.cois.2023.101082] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 06/26/2023] [Accepted: 06/27/2023] [Indexed: 07/09/2023]
Abstract
Extracting spatial information from temporal stimulus patterns is essential for sensory perception (e.g. visual motion direction detection or concurrent sound segregation), but this process remains understudied in olfaction. Animals rely on olfaction to locate resources and dangers. In open environments, where odors are dispersed by turbulent wind, detection of wind direction seems crucial for odor source localization. However, recent studies showed that insects can extract spatial information from the odor stimulus itself, independently from sensing wind direction. This remarkable ability is achieved by detecting the fine-scale temporal pattern of odor encounters, which contains information about the location and size of an odor source, and the distance between different odor sources.
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Affiliation(s)
- Paul Szyszka
- Department of Zoology, University of Otago, Dunedin, New Zealand.
| | - Thierry Emonet
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, USA
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2
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Dasgupta D, Warner TPA, Erskine A, Schaefer AT. Coupling of Mouse Olfactory Bulb Projection Neurons to Fluctuating Odor Pulses. J Neurosci 2022; 42:4278-4296. [PMID: 35440491 PMCID: PMC9145232 DOI: 10.1523/jneurosci.1422-21.2022] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Revised: 03/24/2022] [Accepted: 03/29/2022] [Indexed: 11/28/2022] Open
Abstract
Odors are transported by turbulent air currents, creating complex temporal fluctuations in odor concentration that provide a potentially informative stimulus dimension. We have shown that mice are able to discriminate odor stimuli based on their temporal structure, indicating that information contained in the temporal structure of odor plumes can be extracted by the mouse olfactory system. Here, using in vivo extracellular and intracellular electrophysiological recordings, we show that mitral cells (MCs) and tufted cells (TCs) of the male C57BL/6 mouse olfactory bulb can encode the dominant temporal frequencies present in odor stimuli up to at least 20 Hz. A substantial population of cell-odor pairs showed significant coupling of their subthreshold membrane potential with the odor stimulus at both 2 Hz (29/70) and the suprasniff frequency 20 Hz (24/70). Furthermore, mitral/tufted cells (M/TCs) show differential coupling of their membrane potential to odor concentration fluctuations with tufted cells coupling more strongly for the 20 Hz stimulation. Frequency coupling was always observed to be invariant to odor identity, and M/TCs that coupled well to a mixture also coupled to at least one of the components of the mixture. Interestingly, pharmacological blocking of the inhibitory circuitry strongly modulated frequency coupling of cell-odor pairs at both 2 Hz (10/15) and 20 Hz (9/15). These results provide insight into how both cellular and circuit properties contribute to the encoding of temporal odor features in the mouse olfactory bulb.SIGNIFICANCE STATEMENT Odors in the natural environment have a strong temporal structure that can be extracted and used by mice in their behavior. Here, using in vivo extracellular and intracellular electrophysiological techniques, we show that the projection neurons in the olfactory bulb can encode and couple to the dominant frequency present in an odor stimulus. Furthermore, frequency coupling was observed to be differential between mitral and tufted cells and was odor invariant but strongly modulated by local inhibitory circuits. In summary, this study provides insight into how both cellular and circuit properties modulate encoding of odor temporal features in the mouse olfactory bulb.
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Affiliation(s)
- Debanjan Dasgupta
- Sensory Circuits and Neurotechnology Laboratory, Francis Crick Institute, London NW1 1AT, United Kingdom
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, United Kingdom
| | - Tom P A Warner
- Sensory Circuits and Neurotechnology Laboratory, Francis Crick Institute, London NW1 1AT, United Kingdom
| | - Andrew Erskine
- Sensory Circuits and Neurotechnology Laboratory, Francis Crick Institute, London NW1 1AT, United Kingdom
| | - Andreas T Schaefer
- Sensory Circuits and Neurotechnology Laboratory, Francis Crick Institute, London NW1 1AT, United Kingdom
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, United Kingdom
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3
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Influences of Indication Response Requirement and Target Prevalence on Dogs’ Performance in a Scent-detection Task. Appl Anim Behav Sci 2022. [DOI: 10.1016/j.applanim.2022.105657] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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4
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Neupert S, McCulloch GA, Foster BJ, Waters JM, Szyszka P. Reduced olfactory acuity in recently flightless insects suggests rapid regressive evolution. BMC Ecol Evol 2022; 22:50. [PMID: 35429979 PMCID: PMC9013461 DOI: 10.1186/s12862-022-02005-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Accepted: 04/08/2022] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Insects have exceptionally fast smelling capabilities, and some can track the temporal structure of odour plumes at rates above 100 Hz. It has been hypothesized that this fast smelling capability is an adaptation for flying. We test this hypothesis by comparing the olfactory acuity of sympatric flighted versus flightless lineages within a wing-polymorphic stonefly species.
Results
Our analyses of olfactory receptor neuron responses reveal that recently-evolved flightless lineages have reduced olfactory acuity. By comparing flighted versus flightless ecotypes with similar genetic backgrounds, we eliminate other confounding factors that might have affected the evolution of their olfactory reception mechanisms. Our detection of different patterns of reduced olfactory response strength and speed in independently wing-reduced lineages suggests parallel evolution of reduced olfactory acuity.
Conclusions
These reductions in olfactory acuity echo the rapid reduction of wings themselves, and represent an olfactory parallel to the convergent phenotypic shifts seen under selective gradients in other sensory systems (e.g. parallel loss of vision in cave fauna). Our study provides evidence for the hypothesis that flight poses a selective pressure on the speed and strength of olfactory receptor neuron responses and emphasizes the energetic costs of rapid olfaction.
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5
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Cai X, Guo Y, Bian L, Luo Z, Li Z, Xiu C, Fu N, Chen Z. Variation in the ratio of compounds in a plant volatile blend during transmission by wind. Sci Rep 2022; 12:6176. [PMID: 35418592 PMCID: PMC9007946 DOI: 10.1038/s41598-022-09450-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 02/18/2022] [Indexed: 11/30/2022] Open
Abstract
For plant volatiles to mediate interactions in tritrophic systems, they must convey accurate and reliable information to insects. However, it is unknown whether the ratio of compounds in plant volatile blends remains stable during wind transmission. In this study, volatiles released from an odor source were collected at different points in a wind tunnel and analyzed. The variation in the amounts of volatiles collected at different points formed a rough cone shape. The amounts of volatiles collected tended to decrease with increasing distance from the odor source. Principal component analyses showed that the volatile profiles were dissimilar among different collection points. The profiles of volatiles collected nearest the odor source were the most similar to the released odor. Higher wind speed resulted in a clearer spatial distribution of volatile compounds. Thus, variations in the ratios of compounds in odor plumes exist even during transport over short distances.
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Affiliation(s)
- Xiaoming Cai
- Key Laboratory of Tea Biology and Resource Utilization, Ministry of Agriculture, Tea Research Institute, Chinese Academy of Agricultural Science, Hangzhou, 310008, China
| | - Yuhang Guo
- Key Laboratory of Tea Biology and Resource Utilization, Ministry of Agriculture, Tea Research Institute, Chinese Academy of Agricultural Science, Hangzhou, 310008, China
| | - Lei Bian
- Key Laboratory of Tea Biology and Resource Utilization, Ministry of Agriculture, Tea Research Institute, Chinese Academy of Agricultural Science, Hangzhou, 310008, China
| | - Zongxiu Luo
- Key Laboratory of Tea Biology and Resource Utilization, Ministry of Agriculture, Tea Research Institute, Chinese Academy of Agricultural Science, Hangzhou, 310008, China
| | - Zhaoqun Li
- Key Laboratory of Tea Biology and Resource Utilization, Ministry of Agriculture, Tea Research Institute, Chinese Academy of Agricultural Science, Hangzhou, 310008, China
| | - Chunli Xiu
- Key Laboratory of Tea Biology and Resource Utilization, Ministry of Agriculture, Tea Research Institute, Chinese Academy of Agricultural Science, Hangzhou, 310008, China
| | - Nanxia Fu
- Key Laboratory of Tea Biology and Resource Utilization, Ministry of Agriculture, Tea Research Institute, Chinese Academy of Agricultural Science, Hangzhou, 310008, China
| | - Zongmao Chen
- Key Laboratory of Tea Biology and Resource Utilization, Ministry of Agriculture, Tea Research Institute, Chinese Academy of Agricultural Science, Hangzhou, 310008, China.
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6
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Jayaram V, Kadakia N, Emonet T. Sensing complementary temporal features of odor signals enhances navigation of diverse turbulent plumes. eLife 2022; 11:e72415. [PMID: 35072625 PMCID: PMC8871351 DOI: 10.7554/elife.72415] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 01/20/2022] [Indexed: 11/13/2022] Open
Abstract
We and others have shown that during odor plume navigation, walking Drosophila melanogaster bias their motion upwind in response to both the frequency of their encounters with the odor (Demir et al., 2020) and the intermittency of the odor signal, which we define to be the fraction of time the signal is above a detection threshold (Alvarez-Salvado et al., 2018). Here, we combine and simplify previous mathematical models that recapitulated these data to investigate the benefits of sensing both of these temporal features and how these benefits depend on the spatiotemporal statistics of the odor plume. Through agent-based simulations, we find that navigators that only use frequency or intermittency perform well in some environments - achieving maximal performance when gains are near those inferred from experiment - but fail in others. Robust performance across diverse environments requires both temporal modalities. However, we also find a steep trade-off when using both sensors simultaneously, suggesting a strong benefit to modulating how much each sensor is weighted, rather than using both in a fixed combination across plumes. Finally, we show that the circuitry of the Drosophila olfactory periphery naturally enables simultaneous intermittency and frequency sensing, enhancing robust navigation through a diversity of odor environments. Together, our results suggest that the first stage of olfactory processing selects and encodes temporal features of odor signals critical to real-world navigation tasks.
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Affiliation(s)
- Viraaj Jayaram
- Department of Physics, Yale UniversityNew HavenUnited States
- Department of Molecular, Cellular and Developmental Biology, Yale UniversityNew HavenUnited States
- Quantitative Biology Institute, Yale UniversityNew HavenUnited States
| | - Nirag Kadakia
- Department of Molecular, Cellular and Developmental Biology, Yale UniversityNew HavenUnited States
- Quantitative Biology Institute, Yale UniversityNew HavenUnited States
| | - Thierry Emonet
- Department of Physics, Yale UniversityNew HavenUnited States
- Department of Molecular, Cellular and Developmental Biology, Yale UniversityNew HavenUnited States
- Quantitative Biology Institute, Yale UniversityNew HavenUnited States
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7
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Pannunzi M, Nowotny T. Non-synaptic interactions between olfactory receptor neurons, a possible key feature of odor processing in flies. PLoS Comput Biol 2021; 17:e1009583. [PMID: 34898600 PMCID: PMC8668107 DOI: 10.1371/journal.pcbi.1009583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 10/22/2021] [Indexed: 11/28/2022] Open
Abstract
When flies explore their environment, they encounter odors in complex, highly intermittent plumes. To navigate a plume and, for example, find food, they must solve several challenges, including reliably identifying mixtures of odorants and their intensities, and discriminating odorant mixtures emanating from a single source from odorants emitted from separate sources and just mixing in the air. Lateral inhibition in the antennal lobe is commonly understood to help solving these challenges. With a computational model of the Drosophila olfactory system, we analyze the utility of an alternative mechanism for solving them: Non-synaptic ("ephaptic") interactions (NSIs) between olfactory receptor neurons that are stereotypically co-housed in the same sensilla. We find that NSIs improve mixture ratio detection and plume structure sensing and do so more efficiently than the traditionally considered mechanism of lateral inhibition in the antennal lobe. The best performance is achieved when both mechanisms work in synergy. However, we also found that NSIs decrease the dynamic range of co-housed ORNs, especially when they have similar sensitivity to an odorant. These results shed light, from a functional perspective, on the role of NSIs, which are normally avoided between neurons, for instance by myelination.
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Affiliation(s)
- Mario Pannunzi
- School of Engineering and Informatics, University of Sussex, Brighton, United Kingdom
| | - Thomas Nowotny
- School of Engineering and Informatics, University of Sussex, Brighton, United Kingdom
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8
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Kuruppath P, Belluscio L. The influence of stimulus duration on olfactory perception. PLoS One 2021; 16:e0252931. [PMID: 34111206 PMCID: PMC8191971 DOI: 10.1371/journal.pone.0252931] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 05/25/2021] [Indexed: 12/04/2022] Open
Abstract
The duration of a stimulus plays an important role in the coding of sensory information. The role of stimulus duration is extensively studied in the tactile, visual, and auditory system. In the olfactory system, temporal properties of the stimulus are key for obtaining information when an odor is released in the environment. However, how the stimulus duration influences the odor perception is not well understood. To test this, we activated the olfactory bulbs with blue light in mice expressing channelrhodopsin in the olfactory sensory neurons (OSNs) and assessed the relevance of stimulus duration on olfactory perception using foot shock associated active avoidance behavioral task on a "two-arms maze". Our behavior data demonstrate that the stimulus duration plays an important role in olfactory perception and the associated behavioral responses.
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Affiliation(s)
- Praveen Kuruppath
- Developmental Neural Plasticity Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Leonardo Belluscio
- Developmental Neural Plasticity Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States of America
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9
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Fast odour dynamics are encoded in the olfactory system and guide behaviour. Nature 2021; 593:558-563. [PMID: 33953395 PMCID: PMC7611658 DOI: 10.1038/s41586-021-03514-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 03/23/2021] [Indexed: 02/03/2023]
Abstract
Odours are transported in turbulent plumes, which result in rapid concentration fluctuations1,2 that contain rich information about the olfactory scenery, such as the composition and location of an odour source2-4. However, it is unclear whether the mammalian olfactory system can use the underlying temporal structure to extract information about the environment. Here we show that ten-millisecond odour pulse patterns produce distinct responses in olfactory receptor neurons. In operant conditioning experiments, mice discriminated temporal correlations of rapidly fluctuating odours at frequencies of up to 40 Hz. In imaging and electrophysiological recordings, such correlation information could be readily extracted from the activity of mitral and tufted cells-the output neurons of the olfactory bulb. Furthermore, temporal correlation of odour concentrations5 reliably predicted whether odorants emerged from the same or different sources in naturalistic environments with complex airflow. Experiments in which mice were trained on such tasks and probed using synthetic correlated stimuli at different frequencies suggest that mice can use the temporal structure of odours to extract information about space. Thus, the mammalian olfactory system has access to unexpectedly fast temporal features in odour stimuli. This endows animals with the capacity to overcome key behavioural challenges such as odour source separation5, figure-ground segregation6 and odour localization7 by extracting information about space from temporal odour dynamics.
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10
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Abstract
With less than a million neurons, the western honeybee Apis mellifera is capable of complex olfactory behaviors and provides an ideal model for investigating the neurophysiology of the olfactory circuit and the basis of olfactory perception and learning. Here, we review the most fundamental aspects of honeybee's olfaction: first, we discuss which odorants dominate its environment, and how bees use them to communicate and regulate colony homeostasis; then, we describe the neuroanatomy and the neurophysiology of the olfactory circuit; finally, we explore the cellular and molecular mechanisms leading to olfactory memory formation. The vastity of histological, neurophysiological, and behavioral data collected during the last century, together with new technological advancements, including genetic tools, confirm the honeybee as an attractive research model for understanding olfactory coding and learning.
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Affiliation(s)
- Marco Paoli
- Research Centre on Animal Cognition, Center for Integrative Biology, CNRS, University of Toulouse, 31062, Toulouse, France.
| | - Giovanni C Galizia
- Department of Neuroscience, University of Konstanz, 78457, Konstanz, Germany.
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11
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Brachi G, Ruiz-Ramírez J, Dogra P, Wang Z, Cristini V, Ciardelli G, Rostomily RC, Ferrari M, Mikheev AM, Blanco E, Mattu C. Intratumoral injection of hydrogel-embedded nanoparticles enhances retention in glioblastoma. NANOSCALE 2020; 12:23838-23850. [PMID: 33237080 PMCID: PMC8062960 DOI: 10.1039/d0nr05053a] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 10/24/2020] [Indexed: 05/07/2023]
Abstract
Intratumoral drug delivery is a promising approach for the treatment of glioblastoma multiforme (GBM). However, drug washout remains a major challenge in GBM therapy. Our strategy, aimed at reducing drug clearance and enhancing site-specific residence time, involves the local administration of a multi-component system comprised of nanoparticles (NPs) embedded within a thermosensitive hydrogel (HG). Herein, our objective was to examine the distribution of NPs and their cargo following intratumoral administration of this system in GBM. We hypothesized that the HG matrix, which undergoes rapid gelation upon increases in temperature, would contribute towards heightened site-specific retention and permanence of NPs in tumors. BODIPY-containing, infrared dye-labeled polymeric NPs embedded in a thermosensitive HG (HG-NPs) were fabricated and characterized. Retention and distribution dynamics were subsequently examined over time in orthotopic GBM-bearing mice. Results demonstrate that the HG-NPs system significantly improved site-specific, long-term retention of both NPs and BODIPY, with co-localization analyses showing that HG-NPs covered larger areas of the tumor and the peri-tumor region at later time points. Moreover, NPs released from the HG were shown to undergo uptake by surrounding GBM cells. Findings suggest that intratumoral delivery with HG-NPs has immense potential for GBM treatment, as well as other strategies where site-specific, long-term retention of therapeutic agents is warranted.
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Affiliation(s)
- Giulia Brachi
- Politecnico di Torino
, DIMEAS
,
C.so Duca degli Abruzzi 24
, 10129 Torino
, Italy
.
; Tel: +390110906792
- Department of Nanomedicine
, Houston Methodist Research Institute
,
6670 Bertner Ave
, Houston
, TX 77030
, USA
| | - Javier Ruiz-Ramírez
- Mathematics in Medicine Program
, Houston Methodist Research Institute
,
6670 Bertner Ave
, Houston
, TX 77030
, USA
| | - Prashant Dogra
- Mathematics in Medicine Program
, Houston Methodist Research Institute
,
6670 Bertner Ave
, Houston
, TX 77030
, USA
| | - Zhihui Wang
- Mathematics in Medicine Program
, Houston Methodist Research Institute
,
6670 Bertner Ave
, Houston
, TX 77030
, USA
| | - Vittorio Cristini
- Mathematics in Medicine Program
, Houston Methodist Research Institute
,
6670 Bertner Ave
, Houston
, TX 77030
, USA
| | - Gianluca Ciardelli
- Politecnico di Torino
, DIMEAS
,
C.so Duca degli Abruzzi 24
, 10129 Torino
, Italy
.
; Tel: +390110906792
| | - Robert C. Rostomily
- Department of Neurosurgery
, Houston Methodist Research Institute
,
6670 Bertner Ave
, Houston
, TX 77030
, USA
| | - Mauro Ferrari
- Department of Nanomedicine
, Houston Methodist Research Institute
,
6670 Bertner Ave
, Houston
, TX 77030
, USA
| | - Andrei M. Mikheev
- Department of Neurosurgery
, Houston Methodist Research Institute
,
6670 Bertner Ave
, Houston
, TX 77030
, USA
| | - Elvin Blanco
- Department of Nanomedicine
, Houston Methodist Research Institute
,
6670 Bertner Ave
, Houston
, TX 77030
, USA
| | - Clara Mattu
- Politecnico di Torino
, DIMEAS
,
C.so Duca degli Abruzzi 24
, 10129 Torino
, Italy
.
; Tel: +390110906792
- Department of Nanomedicine
, Houston Methodist Research Institute
,
6670 Bertner Ave
, Houston
, TX 77030
, USA
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12
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Penker S, Licht T, Hofer KT, Rokni D. Mixture Coding and Segmentation in the Anterior Piriform Cortex. Front Syst Neurosci 2020; 14:604718. [PMID: 33328914 PMCID: PMC7710992 DOI: 10.3389/fnsys.2020.604718] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 11/02/2020] [Indexed: 12/14/2022] Open
Abstract
Coding of odorous stimuli has been mostly studied using single isolated stimuli. However, a single sniff of air in a natural environment is likely to introduce airborne chemicals emitted by multiple objects into the nose. The olfactory system is therefore faced with the task of segmenting odor mixtures to identify objects in the presence of rich and often unpredictable backgrounds. The piriform cortex is thought to be the site of object recognition and scene segmentation, yet the nature of its responses to odorant mixtures is largely unknown. In this study, we asked two related questions. (1) How are mixtures represented in the piriform cortex? And (2) Can the identity of individual mixture components be read out from mixture representations in the piriform cortex? To answer these questions, we recorded single unit activity in the piriform cortex of naïve mice while sequentially presenting single odorants and their mixtures. We find that a normalization model explains mixture responses well, both at the single neuron, and at the population level. Additionally, we show that mixture components can be identified from piriform cortical activity by pooling responses of a small population of neurons-in many cases a single neuron is sufficient. These results indicate that piriform cortical representations are well suited to perform figure-background segmentation without the need for learning.
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Affiliation(s)
| | | | | | - Dan Rokni
- Department of Medical Neurobiology, School of Medicine and IMRIC, The Hebrew University of Jerusalem, Jerusalem, Israel
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13
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Pannunzi M, Nowotny T. Non-synaptic interactions between olfactory receptor neurons, a possible key feature of odor processing in flies.. [DOI: 10.1101/2020.07.23.217216] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
Abstract
AbstractWhen flies explore their environment, they encounter odors in complex, highly intermittent plumes. To navigate a plume and, for example, find food, they must solve several challenges, including reliably identifying mixtures of odorants and their intensities, and discriminating odorant mixtures emanating from a single source from odorants emitted from separate sources and just mixing in the air. Lateral inhibition in the antennal lobe is commonly understood to help solving these challenges. With a computational model of the Drosophila olfactory system, we analyze the utility of an alternative mechanism for solving them: Non-synaptic (“ephaptic”) interactions (NSIs) between olfactory receptor neurons that are stereotypically co-housed in the same sensilla.We found that NSIs improve mixture ratio detection and plume structure sensing and they do so more efficiently than the traditionally considered mechanism of lateral inhibition in the antennal lobe. However, we also found that NSIs decrease the dynamic range of co-housed ORNs, especially when they have similar sensitivity to an odorant. These results shed light, from a functional perspective, on the role of NSIs, which are normally avoided between neurons, for instance by myelination.Author summaryMyelin is important to isolate neurons and avoid disruptive electrical interference between them; it can be found in almost any neural assembly. However, there are a few exceptions to this rule and it remains unclear why. One particularly interesting case is the electrical interaction between olfactory sensory neurons co-housed in the sensilla of insects. Here, we created a computational model of the early stages of the Drosophila olfactory system and observed that the electrical interference between olfactory receptor neurons can be a useful trait that can help flies, and other insects, to navigate the complex plumes of odorants in their natural environment.With the model we were able to shed new light on the trade-off of adopting this mechanism: We found that the non-synaptic interactions (NSIs) improve both the identification of the concentration ratio in mixtures of odorants and the discrimination of odorant mixtures emanating from a single source from odorants emitted from separate sources – both highly advantageous. However, they also decrease the dynamic range of the olfactory sensory neurons – a clear disadvantage.
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14
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Desurmont GA, von Arx M, Turlings TCJ, Schiestl FP. Floral Odors Can Interfere With the Foraging Behavior of Parasitoids Searching for Hosts. Front Ecol Evol 2020. [DOI: 10.3389/fevo.2020.00148] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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15
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Abstract
Habituation is a form of simple memory that suppresses neural activity in response to repeated, neutral stimuli. This process is critical in helping organisms guide attention toward the most salient and novel features in the environment. Here, we follow known circuit mechanisms in the fruit fly olfactory system to derive a simple algorithm for habituation. We show, both empirically and analytically, that this algorithm is able to filter out redundant information, enhance discrimination between odors that share a similar background, and improve detection of novel components in odor mixtures. Overall, we propose an algorithmic perspective on the biological mechanism of habituation and use this perspective to understand how sensory physiology can affect odor perception. Our framework may also help toward understanding the effects of habituation in other more sophisticated neural systems.
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16
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Betkiewicz R, Lindner B, Nawrot MP. Circuit and Cellular Mechanisms Facilitate the Transformation from Dense to Sparse Coding in the Insect Olfactory System. eNeuro 2020; 7:ENEURO.0305-18.2020. [PMID: 32132095 PMCID: PMC7294456 DOI: 10.1523/eneuro.0305-18.2020] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2018] [Revised: 10/31/2019] [Accepted: 02/19/2020] [Indexed: 11/21/2022] Open
Abstract
Transformations between sensory representations are shaped by neural mechanisms at the cellular and the circuit level. In the insect olfactory system, the encoding of odor information undergoes a transition from a dense spatiotemporal population code in the antennal lobe to a sparse code in the mushroom body. However, the exact mechanisms shaping odor representations and their role in sensory processing are incompletely identified. Here, we investigate the transformation from dense to sparse odor representations in a spiking model of the insect olfactory system, focusing on two ubiquitous neural mechanisms: spike frequency adaptation at the cellular level and lateral inhibition at the circuit level. We find that cellular adaptation is essential for sparse representations in time (temporal sparseness), while lateral inhibition regulates sparseness in the neuronal space (population sparseness). The interplay of both mechanisms shapes spatiotemporal odor representations, which are optimized for the discrimination of odors during stimulus onset and offset. Response pattern correlation across different stimuli showed a nonmonotonic dependence on the strength of lateral inhibition with an optimum at intermediate levels, which is explained by two counteracting mechanisms. In addition, we find that odor identity is stored on a prolonged timescale in the adaptation levels but not in the spiking activity of the principal cells of the mushroom body, providing a testable hypothesis for the location of the so-called odor trace.
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Affiliation(s)
- Rinaldo Betkiewicz
- Bernstein Center for Computational Neuroscience Berlin, 10115 Berlin, Germany
- Computational Systems Neuroscience, Institute of Zoology, University of Cologne, 50674 Cologne, Germany
- Department of Physics, Humboldt University Berlin, 12489 Berlin, Germany
| | - Benjamin Lindner
- Bernstein Center for Computational Neuroscience Berlin, 10115 Berlin, Germany
- Department of Physics, Humboldt University Berlin, 12489 Berlin, Germany
| | - Martin P Nawrot
- Bernstein Center for Computational Neuroscience Berlin, 10115 Berlin, Germany
- Computational Systems Neuroscience, Institute of Zoology, University of Cologne, 50674 Cologne, Germany
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17
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Xu M, Dupuis-Roy N, Jiang J, Guo C, Xiao X. Event-Related Brain Potentials Associated With the Olfactory-Visual Stroop Effect and Its Modulation by Olfactory-Induced Emotional States. Front Psychol 2020; 11:583. [PMID: 32328011 PMCID: PMC7160315 DOI: 10.3389/fpsyg.2020.00583] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2019] [Accepted: 03/11/2020] [Indexed: 11/23/2022] Open
Abstract
This study investigated the event-related brain potentials associated with the olfactory-visual cross-modal Stroop effect and its modulation by olfactory-induced and self-reported affective states. Eighteen healthy participants were presented with an olfactory stimulus and the image of a plant, and they had to categorize the olfactory attribute of the image as “aromatic” or “pungent” by pressing the relevant button as quickly as possible. The type of olfactory-visual stimuli (congruent or incongruent) and the valence of the olfactory-induced emotional states (positive or negative) were manipulated following a 2 × 2 factorial design. Interference effects were observed at the behavioral and the electrophysiological levels: response times recorded in the incongruent condition were higher than those observed in the congruent condition; an incongruent minus congruent negative difference component was discovered between 350 and 550 ms after stimulus onset in the negative—but not in the positive—olfactory-induced emotional state condition. This ND350-550 component was interpreted as reflecting the amount of selective attention involved in the olfactory-visual cross-modal Stroop effect. These results are also consistent with a facilitatory effect of positive emotional state on selective attention which could reduce brain potentials associated with the cross-modal interference effect.
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Affiliation(s)
- Miaomiao Xu
- School of Public Health and Management, Chongqing Medical University, Chongqing, China.,Research Center for Medicine and Social Development, Chongqing Medical University, Chongqing, China.,Innovation Center for Social Risk Governance in Health, Chongqing Medical University, Chongqing, China
| | | | - Jun Jiang
- Department of Basic Psychology, School of Psychology, Third Military Medical University, Chongqing, China
| | - Chengyao Guo
- School of Public Health and Management, Chongqing Medical University, Chongqing, China
| | - Xiao Xiao
- School of Public Health and Management, Chongqing Medical University, Chongqing, China.,Research Center for Medicine and Social Development, Chongqing Medical University, Chongqing, China.,Innovation Center for Social Risk Governance in Health, Chongqing Medical University, Chongqing, China
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18
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Gorur-Shandilya S, Martelli C, Demir M, Emonet T. Controlling and measuring dynamic odorant stimuli in the laboratory. ACTA ACUST UNITED AC 2019; 222:jeb.207787. [PMID: 31672728 DOI: 10.1242/jeb.207787] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 10/24/2019] [Indexed: 12/28/2022]
Abstract
Animals experience complex odorant stimuli that vary widely in composition, intensity and temporal properties. However, stimuli used to study olfaction in the laboratory are much simpler. This mismatch arises from the challenges in measuring and controlling them precisely and accurately. Even simple pulses can have diverse kinetics that depend on their molecular identity. Here, we introduce a model that describes how stimulus kinetics depend on the molecular identity of the odorant and the geometry of the delivery system. We describe methods to deliver dynamic odorant stimuli of several types, including broadly distributed stimuli that reproduce some of the statistics of naturalistic plumes, in a reproducible and precise manner. Finally, we introduce a method to calibrate a photo-ionization detector to any odorant it can detect, using no additional components. Our approaches are affordable and flexible and can be used to advance our understanding of how olfactory neurons encode real-world odor signals.
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Affiliation(s)
- Srinivas Gorur-Shandilya
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT 06511, USA.,Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06511, USA
| | - Carlotta Martelli
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06511, USA.,Department of Biology, University of Konstanz, Konstanz 78457, Germany
| | - Mahmut Demir
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06511, USA
| | - Thierry Emonet
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT 06511, USA .,Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06511, USA.,Department of Physics, Yale University, New Haven, CT 06511, USA
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19
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Pannunzi M, Nowotny T. Odor Stimuli: Not Just Chemical Identity. Front Physiol 2019; 10:1428. [PMID: 31827441 PMCID: PMC6890726 DOI: 10.3389/fphys.2019.01428] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 11/04/2019] [Indexed: 01/14/2023] Open
Abstract
In most sensory modalities the underlying physical phenomena are well understood, and stimulus properties can be precisely controlled. In olfaction, the situation is different. The presence of specific chemical compounds in the air (or water) is the root cause for perceived odors, but it remains unknown what organizing principles, equivalent to wavelength for light, determine the dimensions of odor space. Equally important, but less in the spotlight, odor stimuli are also complex with respect to their physical properties, including concentration and time-varying spatio-temporal distribution. We still lack a complete understanding or control over these properties, in either experiments or theory. In this review, we will concentrate on two important aspects of the physical properties of odor stimuli beyond the chemical identity of the odorants: (1) The amplitude of odor stimuli and their temporal dynamics. (2) The spatio-temporal structure of odor plumes in a natural environment. Concerning these issues, we ask the following questions: (1) Given any particular experimental protocol for odor stimulation, do we have a realistic estimate of the odorant concentration in the air, and at the olfactory receptor neurons? Can we control, or at least know, the dynamics of odorant concentration at olfactory receptor neurons? (2) What do we know of the spatio-temporal structure of odor stimuli in a natural environment both from a theoretical and experimental perspective? And how does this change if we consider mixtures of odorants? For both topics, we will briefly summarize the underlying principles of physics and review the experimental and theoretical Neuroscience literature, focusing on the aspects that are relevant to animals’ physiology and behavior. We hope that by bringing the physical principles behind odor plume landscapes to the fore we can contribute to promoting a new generation of experiments and models.
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20
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Lan B, Kanzaki R, Ando N. Dropping Counter: A Detection Algorithm for Identifying Odour-Evoked Responses from Noisy Electroantennograms Measured by a Flying Robot. SENSORS 2019; 19:s19204574. [PMID: 31640187 PMCID: PMC6832354 DOI: 10.3390/s19204574] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 10/12/2019] [Accepted: 10/18/2019] [Indexed: 11/30/2022]
Abstract
The electroantennogram (EAG) is a technique used for measuring electrical signals from the antenna of an insect. Its rapid response time, quick recovery speed, and high sensitivity make it suitable for odour-tracking tasks employing mobile robots. However, its application to flying robots has not been extensively studied owing to the electrical and mechanical noises generated. In this study, we investigated the characteristics of the EAG mounted on a tethered flying quadcopter and developed a special counter-based algorithm for detecting the odour-generated responses. As the EAG response is negative, the algorithm creates a window and compares the values inside it. Once a value is smaller than the first one, the counter will increase by one and finally turns the whole signal into a clearer odour stimulated result. By experimental evaluation, the new algorithm gives a higher cross-correlation coefficient when compared with the fixed-threshold method. The result shows that the accuracy of this novel algorithm for recognising odour-evoked EAG signals from noise exceeds that of the traditional method; furthermore, the use of insect antennae as odour sensors for flying robots is demonstrated to be feasible.
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Affiliation(s)
- Bluest Lan
- Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Meguro-ku, Komaba, Tokyo 153-8904, Japan.
| | - Ryohei Kanzaki
- Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Meguro-ku, Komaba, Tokyo 153-8904, Japan.
| | - Noriyasu Ando
- Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Meguro-ku, Komaba, Tokyo 153-8904, Japan.
- Department of Systems Life Engineering, Faculty of Engineering, Maebashi Institute of Technology, 460-1 Kamisadori-cho, Maebashi, Gunma 371-0816, Japan.
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21
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Wu F, Ma C, Han B, Meng L, Hu H, Fang Y, Feng M, Zhang X, Rueppell O, Li J. Behavioural, physiological and molecular changes in alloparental caregivers may be responsible for selection response for female reproductive investment in honey bees. Mol Ecol 2019; 28:4212-4227. [DOI: 10.1111/mec.15207] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 07/31/2019] [Accepted: 07/31/2019] [Indexed: 12/16/2022]
Affiliation(s)
- Fan Wu
- Institute of Apicultural Research/Key Laboratory of Pollinating Insect Biology Ministry of Agriculture Chinese Academy of Agricultural Science Beijing China
| | - Chuan Ma
- Institute of Apicultural Research/Key Laboratory of Pollinating Insect Biology Ministry of Agriculture Chinese Academy of Agricultural Science Beijing China
| | - Bin Han
- Institute of Apicultural Research/Key Laboratory of Pollinating Insect Biology Ministry of Agriculture Chinese Academy of Agricultural Science Beijing China
| | - Lifeng Meng
- Institute of Apicultural Research/Key Laboratory of Pollinating Insect Biology Ministry of Agriculture Chinese Academy of Agricultural Science Beijing China
| | - Han Hu
- Institute of Apicultural Research/Key Laboratory of Pollinating Insect Biology Ministry of Agriculture Chinese Academy of Agricultural Science Beijing China
| | - Yu Fang
- Institute of Apicultural Research/Key Laboratory of Pollinating Insect Biology Ministry of Agriculture Chinese Academy of Agricultural Science Beijing China
| | - Mao Feng
- Institute of Apicultural Research/Key Laboratory of Pollinating Insect Biology Ministry of Agriculture Chinese Academy of Agricultural Science Beijing China
| | - Xufeng Zhang
- Institute of Apicultural Research/Key Laboratory of Pollinating Insect Biology Ministry of Agriculture Chinese Academy of Agricultural Science Beijing China
| | - Olav Rueppell
- Department of Biology University of North Carolina at Greensboro Greensboro NC USA
| | - Jianke Li
- Institute of Apicultural Research/Key Laboratory of Pollinating Insect Biology Ministry of Agriculture Chinese Academy of Agricultural Science Beijing China
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22
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Martinez D, Burgués J, Marco S. Fast Measurements with MOX Sensors: A Least-Squares Approach to Blind Deconvolution. SENSORS 2019; 19:s19184029. [PMID: 31540524 PMCID: PMC6766816 DOI: 10.3390/s19184029] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 09/09/2019] [Accepted: 09/12/2019] [Indexed: 11/28/2022]
Abstract
Metal oxide (MOX) sensors are widely used for chemical sensing due to their low cost, miniaturization, low power consumption and durability. Yet, getting instantaneous measurements of fluctuating gas concentration in turbulent plumes is not possible due to their slow response time. In this paper, we show that the slow response of MOX sensors can be compensated by deconvolution, provided that an invertible, parametrized, sensor model is available. We consider a nonlinear, first-order dynamic model that is mathematically tractable for MOX identification and deconvolution. By transforming the sensor signal in the log-domain, the system becomes linear in the parameters and these can be estimated by the least-squares techniques. Moreover, we use the MOX diversity in a sensor array to avoid training with a supervised signal. The information provided by two (or more) sensors, exposed to the same flow but responding with different dynamics, is exploited to recover the ground truth signal (gas input). This approach is known as blind deconvolution. We demonstrate its efficiency on MOX sensors recorded in turbulent plumes. The reconstructed signal is similar to the one obtained with a fast photo-ionization detector (PID). The technique is thus relevant to track a fast-changing gas concentration with MOX sensors, resulting in a compensated response time comparable to that of a PID.
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Affiliation(s)
- Dominique Martinez
- Laboratoire Lorrain de Recherche en Informatique et ses Applications (LORIA), CNRS, INRIA, 54506 Vandoeuvre-lès-Nancy, France
- Correspondence:
| | - Javier Burgués
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, Baldiri Reixac 10-12, 08028 Barcelona, Spain; (J.B.); (S.M.)
- Department of Electronics and Biomedical Engineering, Universitat de Barcelona, Marti i Franqués 1, 08028 Barcelona, Spain
| | - Santiago Marco
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, Baldiri Reixac 10-12, 08028 Barcelona, Spain; (J.B.); (S.M.)
- Department of Electronics and Biomedical Engineering, Universitat de Barcelona, Marti i Franqués 1, 08028 Barcelona, Spain
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23
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Conchou L, Lucas P, Meslin C, Proffit M, Staudt M, Renou M. Insect Odorscapes: From Plant Volatiles to Natural Olfactory Scenes. Front Physiol 2019; 10:972. [PMID: 31427985 PMCID: PMC6688386 DOI: 10.3389/fphys.2019.00972] [Citation(s) in RCA: 94] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 07/11/2019] [Indexed: 11/13/2022] Open
Abstract
Olfaction is an essential sensory modality for insects and their olfactory environment is mostly made up of plant-emitted volatiles. The terrestrial vegetation produces an amazing diversity of volatile compounds, which are then transported, mixed, and degraded in the atmosphere. Each insect species expresses a set of olfactory receptors that bind part of the volatile compounds present in its habitat. Insect odorscapes are thus defined as species-specific olfactory spaces, dependent on the local habitat, and dynamic in time. Manipulations of pest-insect odorscapes are a promising approach to answer the strong demand for pesticide-free plant-protection strategies. Moreover, understanding their olfactory environment becomes a major concern in the context of global change and environmental stresses to insect populations. A considerable amount of information is available on the identity of volatiles mediating biotic interactions that involve insects. However, in the large body of research devoted to understanding how insects use olfaction to locate resources, an integrative vision of the olfactory environment has rarely been reached. This article aims to better apprehend the nature of the insect odorscape and its importance to insect behavioral ecology by reviewing the literature specific to different disciplines from plant ecophysiology to insect neuroethology. First, we discuss the determinants of odorscape composition, from the production of volatiles by plants (section "Plant Metabolism and Volatile Emissions") to their filtering during detection by the olfactory system of insects (section "Insect Olfaction: How Volatile Plant Compounds Are Encoded and Integrated by the Olfactory System"). We then summarize the physical and chemical processes by which volatile chemicals distribute in space (section "Transportation of Volatile Plant Compounds and Spatial Aspects of the Odorscape") and time (section "Temporal Aspects: The Dynamics of the Odorscape") in the atmosphere. The following sections consider the ecological importance of background odors in odorscapes and how insects adapt to their olfactory environment. Habitat provides an odor background and a sensory context that modulate the responses of insects to pheromones and other olfactory signals (section "Ecological Importance of Odorscapes"). In addition, insects do not respond inflexibly to single elements in their odorscape but integrate several components of their environment (section "Plasticity and Adaptation to Complex and Variable Odorscapes"). We finally discuss existing methods of odorscape manipulation for sustainable pest insect control and potential future developments in the context of agroecology (section "Odorscapes in Plant Protection and Agroecology").
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Affiliation(s)
- Lucie Conchou
- INRA, Sorbonne Université, INRA, CNRS, UPEC, IRD, University P7, Institute of Ecology and Environmental Sciences of Paris, Paris, France
| | - Philippe Lucas
- INRA, Sorbonne Université, INRA, CNRS, UPEC, IRD, University P7, Institute of Ecology and Environmental Sciences of Paris, Paris, France
| | - Camille Meslin
- INRA, Sorbonne Université, INRA, CNRS, UPEC, IRD, University P7, Institute of Ecology and Environmental Sciences of Paris, Paris, France
| | - Magali Proffit
- CEFE, CNRS, EPHE, IRD, Université de Montpellier, Université Paul-Valéry Montpellier, Montpellier, France
| | - Michael Staudt
- CEFE, CNRS, EPHE, IRD, Université de Montpellier, Université Paul-Valéry Montpellier, Montpellier, France
| | - Michel Renou
- INRA, Sorbonne Université, INRA, CNRS, UPEC, IRD, University P7, Institute of Ecology and Environmental Sciences of Paris, Paris, France
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24
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Sehdev A, Szyszka P. Segregation of Unknown Odors From Mixtures Based on Stimulus Onset Asynchrony in Honey Bees. Front Behav Neurosci 2019; 13:155. [PMID: 31354447 PMCID: PMC6639674 DOI: 10.3389/fnbeh.2019.00155] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 06/25/2019] [Indexed: 01/14/2023] Open
Abstract
Animals use olfaction to search for distant objects. Unlike vision, where objects are spaced out, olfactory information mixes when it reaches olfactory organs. Therefore, efficient olfactory search requires segregating odors that are mixed with background odors. Animals can segregate known odors by detecting short differences in the arrival of mixed odorants (stimulus onset asynchrony). However, it is unclear whether animals can also use stimulus onset asynchrony to segregate odorants that they had no previous experience with and which have no innate or learned relevance (unknown odorants). Using behavioral experiments in honey bees, we here show that stimulus onset asynchrony also improves segregation of those unknown odorants. The stimulus onset asynchrony necessary to segregate unknown odorants is in the range of seconds, which is two orders of magnitude larger than the previously reported stimulus asynchrony sufficient for segregating known odorants. We propose that for unknown odorants, segregating odorant A from a mixture with B requires sensory adaptation to B.
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Affiliation(s)
- Aarti Sehdev
- Department of Biology, Neurobiology, University of Konstanz, Konstanz, Germany
| | - Paul Szyszka
- Department of Biology, Neurobiology, University of Konstanz, Konstanz, Germany
- Department of Zoology, University of Otago, Dunedin, New Zealand
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25
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Martelli C, Fiala A. Slow presynaptic mechanisms that mediate adaptation in the olfactory pathway of Drosophila. eLife 2019; 8:43735. [PMID: 31169499 PMCID: PMC6581506 DOI: 10.7554/elife.43735] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Accepted: 06/05/2019] [Indexed: 12/14/2022] Open
Abstract
The olfactory system encodes odor stimuli as combinatorial activity of populations of neurons whose response depends on stimulus history. How and on which timescales previous stimuli affect these combinatorial representations remains unclear. We use in vivo optical imaging in Drosophila to analyze sensory adaptation at the first synaptic step along the olfactory pathway. We show that calcium signals in the axon terminals of olfactory receptor neurons (ORNs) do not follow the same adaptive properties as the firing activity measured at the antenna. While ORNs calcium responses are sustained on long timescales, calcium signals in the postsynaptic projection neurons (PNs) adapt within tens of seconds. We propose that this slow component of the postsynaptic response is mediated by a slow presynaptic depression of vesicle release and enables the combinatorial population activity of PNs to adjust to the mean and variance of fluctuating odor stimuli.
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Affiliation(s)
- Carlotta Martelli
- Molecular Neurobiology of Behavior, Johann-Friedrich-Blumenbach-Institute for Zoology and Anthropology, University of Goettingen, Goettingen, Germany.,Department of Biology, Neurobiology, University of Konstanz, Konstanz, Germany
| | - André Fiala
- Molecular Neurobiology of Behavior, Johann-Friedrich-Blumenbach-Institute for Zoology and Anthropology, University of Goettingen, Goettingen, Germany
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26
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Olfactory Object Recognition Based on Fine-Scale Stimulus Timing in Drosophila. iScience 2019; 13:113-124. [PMID: 30826726 PMCID: PMC6402261 DOI: 10.1016/j.isci.2019.02.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 01/09/2019] [Accepted: 02/12/2019] [Indexed: 01/31/2023] Open
Abstract
Odorants of behaviorally relevant objects (e.g., food sources) intermingle with those from other sources. Therefore to determine whether an odor source is good or bad—without actually visiting it—animals first need to segregate the odorants from different sources. To do so, animals could use temporal stimulus cues, because odorants from one source exhibit correlated fluctuations, whereas odorants from different sources are less correlated. However, the behaviorally relevant timescales of temporal stimulus cues for odor source segregation remain unclear. Using behavioral experiments with free-flying flies, we show that (1) odorant onset asynchrony increases flies' attraction to a mixture of two odorants with opposing innate or learned valence and (2) attraction does not increase when the attractive odorant arrives first. These data suggest that flies can use stimulus onset asynchrony for odor source segregation and imply temporally precise neural mechanisms for encoding odors and for segregating them into distinct objects. Flies can detect whether two mixed odorants arrive synchronously or asynchronously This temporal sensitivity occurs for odorants with innate and learned valences Flies' behavior suggests use of odor onset asynchrony for odor source segregation
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27
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Abstract
In most sensory modalities the underlying physical phenomena are well understood, and stimulus properties can be precisely controlled. In olfaction, the situation is different. The presence of specific chemical compounds in the air (or water) is the root cause for perceived odors, but it remains unknown what organizing principles, equivalent to wavelength for light, determine the dimensions of odor space. Equally important, but less in the spotlight, odor stimuli are also complex with respect to their physical properties, including concentration and time-varying spatio-temporal distribution. We still lack a complete understanding or control over these properties, in either experiments or theory. In this review, we will concentrate on two important aspects of the physical properties of odor stimuli beyond the chemical identity of the odorants: (1) The amplitude of odor stimuli and their temporal dynamics. (2) The spatio-temporal structure of odor plumes in a natural environment. Concerning these issues, we ask the following questions: (1) Given any particular experimental protocol for odor stimulation, do we have a realistic estimate of the odorant concentration in the air, and at the olfactory receptor neurons? Can we control, or at least know, the dynamics of odorant concentration at olfactory receptor neurons? (2) What do we know of the spatio-temporal structure of odor stimuli in a natural environment both from a theoretical and experimental perspective? And how does this change if we consider mixtures of odorants? For both topics, we will briefly summarize the underlying principles of physics and review the experimental and theoretical Neuroscience literature, focusing on the aspects that are relevant to animals' physiology and behavior. We hope that by bringing the physical principles behind odor plume landscapes to the fore we can contribute to promoting a new generation of experiments and models.
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28
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Odor mixture training enhances dogs' olfactory detection of Home-Made Explosive precursors. Heliyon 2018; 4:e00947. [PMID: 30582032 PMCID: PMC6299160 DOI: 10.1016/j.heliyon.2018.e00947] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 07/21/2018] [Accepted: 11/15/2018] [Indexed: 11/24/2022] Open
Abstract
Complex odor mixtures have traditionally been thought to be perceived configurally, implying that there is little identification of the individual components in the mixture. Prior research has suggested that the chemical and or perceptual similarity of components in a mixture may influence whether they can be detected individually; however, how experience and training influence the ability to identify individual components in complex mixtures (a figure-background segregation) is less clear. Figure-background segregation is a critical task for dogs tasked with discriminating between Home Made Explosives and very similar, but innocuous, complex odor mixtures. In a cross-over experimental design, we evaluated the effect of two training procedures on dogs' ability to identify the presence of a critical oxidizer in complex odor mixtures. In the Mixture training procedure, dogs received odor mixtures that varied from trial to trial with and without an oxidizer. In the more typical procedure for canine detection training, dogs were presented with the pure oxidizer only, and had to discriminate this from decoy mixtures (target-only training). Mixture training led to above chance discrimination of the oxidizer from variable backgrounds and dogs were able to readily generalize performance, with no decrement, to mixtures containing novel odorants. Target-only training, however, led to a precipitous drop in hit rate when the oxidizer was presented in a mixture background containing either familiar and/or novel odorants. Furthermore, by giving Target-only trained dogs Mixture training, they learned to identify the oxidizer in mixtures. Together, these results demonstrate that training method has significant impacts on the perception of components in odor mixtures and highlights the importance of olfactory learning for the effective detection of Home Made Explosives by dogs.
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29
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High Precision of Spike Timing across Olfactory Receptor Neurons Allows Rapid Odor Coding in Drosophila. iScience 2018; 4:76-83. [PMID: 30240755 PMCID: PMC6147046 DOI: 10.1016/j.isci.2018.05.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 04/19/2018] [Accepted: 05/14/2018] [Indexed: 01/10/2023] Open
Abstract
In recent years, it has become evident that olfaction is a fast sense, and millisecond short differences in stimulus onsets are used by animals to analyze their olfactory environment. In contrast, olfactory receptor neurons are thought to be relatively slow and temporally imprecise. These observations have led to a conundrum: how, then, can an animal resolve fast stimulus dynamics and smell with high temporal acuity? Using parallel recordings from olfactory receptor neurons in Drosophila, we found hitherto unknown fast and temporally precise odorant-evoked spike responses, with first spike latencies (relative to odorant arrival) down to 3 ms and with a SD below 1 ms. These data provide new upper bounds for the speed of olfactory processing and suggest that the insect olfactory system could use the precise spike timing for olfactory coding and computation, which can explain insects' rapid processing of temporal stimuli when encountering turbulent odor plumes. Olfactory receptor neuron responses are fast and temporally precise Odor-evoked spikes can occur 3 ms after odorant arrival and jitter less than 1 ms First-spike timing varies over a wider concentration range than spike rate Neural network model demonstrates the plausibility of a spike-timing code for odors
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30
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Strube-Bloss MF, Rössler W. Multimodal integration and stimulus categorization in putative mushroom body output neurons of the honeybee. ROYAL SOCIETY OPEN SCIENCE 2018; 5:171785. [PMID: 29515886 PMCID: PMC5830775 DOI: 10.1098/rsos.171785] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 01/15/2018] [Indexed: 06/11/2023]
Abstract
Flowers attract pollinating insects like honeybees by sophisticated compositions of olfactory and visual cues. Using honeybees as a model to study olfactory-visual integration at the neuronal level, we focused on mushroom body (MB) output neurons (MBON). From a neuronal circuit perspective, MBONs represent a prominent level of sensory-modality convergence in the insect brain. We established an experimental design allowing electrophysiological characterization of olfactory, visual, as well as olfactory-visual induced activation of individual MBONs. Despite the obvious convergence of olfactory and visual pathways in the MB, we found numerous unimodal MBONs. However, a substantial proportion of MBONs (32%) responded to both modalities and thus integrated olfactory-visual information across MB input layers. In these neurons, representation of the olfactory-visual compound was significantly increased compared with that of single components, suggesting an additive, but nonlinear integration. Population analyses of olfactory-visual MBONs revealed three categories: (i) olfactory, (ii) visual and (iii) olfactory-visual compound stimuli. Interestingly, no significant differentiation was apparent regarding different stimulus qualities within these categories. We conclude that encoding of stimulus quality within a modality is largely completed at the level of MB input, and information at the MB output is integrated across modalities to efficiently categorize sensory information for downstream behavioural decision processing.
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31
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Jacob V, Monsempès C, Rospars JP, Masson JB, Lucas P. Olfactory coding in the turbulent realm. PLoS Comput Biol 2017; 13:e1005870. [PMID: 29194457 PMCID: PMC5736211 DOI: 10.1371/journal.pcbi.1005870] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2017] [Revised: 12/19/2017] [Accepted: 11/01/2017] [Indexed: 01/10/2023] Open
Abstract
Long-distance olfactory search behaviors depend on odor detection dynamics. Due to turbulence, olfactory signals travel as bursts of variable concentration and spacing and are characterized by long-tail distributions of odor/no-odor events, challenging the computing capacities of olfactory systems. How animals encode complex olfactory scenes to track the plume far from the source remains unclear. Here we focus on the coding of the plume temporal dynamics in moths. We compare responses of olfactory receptor neurons (ORNs) and antennal lobe projection neurons (PNs) to sequences of pheromone stimuli either with white-noise patterns or with realistic turbulent temporal structures simulating a large range of distances (8 to 64 m) from the odor source. For the first time, we analyze what information is extracted by the olfactory system at large distances from the source. Neuronal responses are analyzed using linear-nonlinear models fitted with white-noise stimuli and used for predicting responses to turbulent stimuli. We found that neuronal firing rate is less correlated with the dynamic odor time course when distance to the source increases because of improper coding during long odor and no-odor events that characterize large distances. Rapid adaptation during long puffs does not preclude however the detection of puff transitions in PNs. Individual PNs but not individual ORNs encode the onset and offset of odor puffs for any temporal structure of stimuli. A higher spontaneous firing rate coupled to an inhibition phase at the end of PN responses contributes to this coding property. This allows PNs to decode the temporal structure of the odor plume at any distance to the source, an essential piece of information moths can use in their tracking behavior.
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Affiliation(s)
- Vincent Jacob
- Institute of Ecology and Environmental Sciences, INRA, route de St Cyr, Versailles, France
- Peuplements végétaux et bioagresseurs en milieu végétal, CIRAD, Université de la Réunion, Saint Pierre, Ile de la Réunion, France
| | - Christelle Monsempès
- Institute of Ecology and Environmental Sciences, INRA, route de St Cyr, Versailles, France
| | - Jean-Pierre Rospars
- Institute of Ecology and Environmental Sciences, INRA, route de St Cyr, Versailles, France
| | - Jean-Baptiste Masson
- Decision and Bayesian Computation, Pasteur Institute, CNRS UMR 3571, 25-28 rue du Dr Roux, 75015 Paris, France
- Bioinformatics and Biostatistics Hub, C3BI, Pasteur Institute, CNRS USR 3756, 25-28 rue du Dr Roux, 75015 Paris, France
| | - Philippe Lucas
- Institute of Ecology and Environmental Sciences, INRA, route de St Cyr, Versailles, France
- * E-mail:
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Nagari M, Szyszka P, Galizia G, Bloch G. Task-Related Phasing of Circadian Rhythms in Antennal Responsiveness to Odorants and Pheromones in Honeybees. J Biol Rhythms 2017; 32:593-608. [PMID: 28984167 DOI: 10.1177/0748730417733573] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The insect antennae receive olfactory information from the environment. In some insects, it has been shown that antennal responsiveness is dynamically regulated by circadian clocks. However, it is unknown how general this phenomenon is and what functions it serves. Circadian regulation in honeybee workers is particularly interesting in this regard because they show natural task-related chronobiological plasticity. Forager bees show strong circadian rhythms in behavior and brain gene expression, whereas nurse bees tend brood around-the-clock and have attenuated circadian rhythms in activity and whole-brain gene expression. Here, we tested the hypothesis that there is task-related plasticity in circadian rhythms of antennal responsiveness to odorants in worker honeybees. We used electroantennogram (EAG) to measure the antennal responsiveness of nurses and foragers to general odorants and pheromones around the day. The capacity to track 10-Hz odorant pulses varied with time of day for both task groups but with different phases. The antennal pulse-tracking capacity was higher during the subjective day for the day-active foragers, whereas it was better during the night for around-the-clock active nurses. The task-related phases of pulse-tracking rhythms were similar for all the tested stimuli. We also found evidence for circadian rhythms in the EAG response magnitude of foragers but not of nurses. To the best of our knowledge, these results provide the first evidence for circadian regulation of antennal olfactory responsiveness and odorant pulse-tracking capacity in bees or any other hymenopteran insect. Importantly, our study shows for the first time that the circadian phase of olfactory responsiveness may be socially regulated.
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Affiliation(s)
- Moshe Nagari
- Department of Ecology, Evolution, and Behavior, The A. Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Paul Szyszka
- Department of Neuroscience, University of Konstanz, Germany
| | | | - Guy Bloch
- Department of Ecology, Evolution, and Behavior, The A. Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
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Ando N, Kanzaki R. Using insects to drive mobile robots - hybrid robots bridge the gap between biological and artificial systems. ARTHROPOD STRUCTURE & DEVELOPMENT 2017; 46:723-735. [PMID: 28254451 DOI: 10.1016/j.asd.2017.02.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 02/21/2017] [Accepted: 02/21/2017] [Indexed: 06/06/2023]
Abstract
The use of mobile robots is an effective method of validating sensory-motor models of animals in a real environment. The well-identified insect sensory-motor systems have been the major targets for modeling. Furthermore, mobile robots implemented with such insect models attract engineers who aim to avail advantages from organisms. However, directly comparing the robots with real insects is still difficult, even if we successfully model the biological systems, because of the physical differences between them. We developed a hybrid robot to bridge the gap. This hybrid robot is an insect-controlled robot, in which a tethered male silkmoth (Bombyx mori) drives the robot in order to localize an odor source. This robot has the following three advantages: 1) from a biomimetic perspective, the robot enables us to evaluate the potential performance of future insect-mimetic robots; 2) from a biological perspective, the robot enables us to manipulate the closed-loop of an onboard insect for further understanding of its sensory-motor system; and 3) the robot enables comparison with insect models as a reference biological system. In this paper, we review the recent works regarding insect-controlled robots and discuss the significance for both engineering and biology.
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Affiliation(s)
- Noriyasu Ando
- Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan.
| | - Ryohei Kanzaki
- Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan
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Biergans SD, Claudianos C, Reinhard J, Galizia CG. DNA methylation mediates neural processing after odor learning in the honeybee. Sci Rep 2017; 7:43635. [PMID: 28240742 PMCID: PMC5378914 DOI: 10.1038/srep43635] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 01/26/2017] [Indexed: 01/04/2023] Open
Abstract
DNA methyltransferases (Dnmts) - epigenetic writers catalyzing the transfer of methyl-groups to cytosine (DNA methylation) - regulate different aspects of memory formation in many animal species. In honeybees, Dnmt activity is required to adjust the specificity of olfactory reward memories and bees' relearning capability. The physiological relevance of Dnmt-mediated DNA methylation in neural networks, however, remains unknown. Here, we investigated how Dnmt activity impacts neuroplasticity in the bees' primary olfactory center, the antennal lobe (AL) an equivalent of the vertebrate olfactory bulb. The AL is crucial for odor discrimination, an indispensable process in forming specific odor memories. Using pharmacological inhibition, we demonstrate that Dnmt activity influences neural network properties during memory formation in vivo. We show that Dnmt activity promotes fast odor pattern separation in trained bees. Furthermore, Dnmt activity during memory formation increases both the number of responding glomeruli and the response magnitude to a novel odor. These data suggest that Dnmt activity is necessary for a form of homoeostatic network control which might involve inhibitory interneurons in the AL network.
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Affiliation(s)
- Stephanie D Biergans
- Queensland Brain Institute, The University of Queensland, Australia.,Neurobiologie, Universität Konstanz, Germany
| | - Charles Claudianos
- Queensland Brain Institute, The University of Queensland, Australia.,Monash Institute of Cognitive and Clinical Neuroscience, Faculty of Medicine, Nursing Health and Sciences, Monash University, Australia
| | - Judith Reinhard
- Queensland Brain Institute, The University of Queensland, Australia
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Raiser G, Galizia CG, Szyszka P. A High-Bandwidth Dual-Channel Olfactory Stimulator for Studying Temporal Sensitivity of Olfactory Processing. Chem Senses 2016; 42:141-151. [PMID: 27988494 DOI: 10.1093/chemse/bjw114] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Animals encounter fine-scale temporal patterns of odorant mixtures that contain information about the distance and number of odorant sources. To study the role of such temporal cues for odorant detection and source localization, one needs odorant delivery devices that are capable of mimicking the temporal stimulus statistics of natural odor plumes. However, current odorant delivery devices either lack temporal resolution or are limited to a single odorant channel. Here, we present an olfactory stimulator that features precise control of high-bandwidth stimulus dynamics, which allows generating arbitrary fluctuating binary odorant mixtures. We provide a comprehensive characterization of the stimulator's performance and use it to demonstrate that odor background affects the temporal resolution of insect olfactory receptor neurons, and we present a hitherto unknown odor pulse-tracking capability of up to 60 Hz in Kenyon cells, which are higher order olfactory neurons of the insect brain. This stimulator might help investigating whether and how animals use temporal stimulus cues for odor detection and source localization. Because the stimulator is easy to replicate it can facilitate generating the same odor stimulus dynamics at different experimental setups and across different labs.
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Affiliation(s)
- Georg Raiser
- Department of Neuroscience, University of Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany and.,International Max-Planck Research School for Organismal Biology, University of Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany
| | - C Giovanni Galizia
- Department of Neuroscience, University of Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany and
| | - Paul Szyszka
- Department of Neuroscience, University of Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany and
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Reisenman CE, Lei H, Guerenstein PG. Neuroethology of Olfactory-Guided Behavior and Its Potential Application in the Control of Harmful Insects. Front Physiol 2016; 7:271. [PMID: 27445858 PMCID: PMC4928593 DOI: 10.3389/fphys.2016.00271] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 06/16/2016] [Indexed: 11/26/2022] Open
Abstract
Harmful insects include pests of crops and storage goods, and vectors of human and animal diseases. Throughout their history, humans have been fighting them using diverse methods. The fairly recent development of synthetic chemical insecticides promised efficient crop and health protection at a relatively low cost. However, the negative effects of those insecticides on human health and the environment, as well as the development of insect resistance, have been fueling the search for alternative control tools. New and promising alternative methods to fight harmful insects include the manipulation of their behavior using synthetic versions of "semiochemicals", which are natural volatile and non-volatile substances involved in the intra- and/or inter-specific communication between organisms. Synthetic semiochemicals can be used as trap baits to monitor the presence of insects, so that insecticide spraying can be planned rationally (i.e., only when and where insects are actually present). Other methods that use semiochemicals include insect annihilation by mass trapping, attract-and- kill techniques, behavioral disruption, and the use of repellents. In the last decades many investigations focused on the neural bases of insect's responses to semiochemicals. Those studies help understand how the olfactory system detects and processes information about odors, which could lead to the design of efficient control tools, including odor baits, repellents or ways to confound insects. Here we review our current knowledge about the neural mechanisms controlling olfactory responses to semiochemicals in harmful insects. We also discuss how this neuroethology approach can be used to design or improve pest/vector management strategies.
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Affiliation(s)
- Carolina E. Reisenman
- Department of Molecular and Cell Biology and Essig Museum of Entomology, University of California, BerkeleyBerkeley, CA, USA
| | - Hong Lei
- Department of Neuroscience, University of ArizonaTucson, AZ, USA
| | - Pablo G. Guerenstein
- Lab. de Estudio de la Biología de Insectos, CICyTTP-CONICETDiamante, Argentina
- Facultad de Ingeniería, Universidad Nacional de Entre RíosOro Verde, Argentina
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Rusch C, Broadhead GT, Raguso RA, Riffell JA. Olfaction in context-sources of nuance in plant-pollinator communication. CURRENT OPINION IN INSECT SCIENCE 2016; 15:53-60. [PMID: 27436732 DOI: 10.1016/j.cois.2016.03.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 03/12/2016] [Accepted: 03/15/2016] [Indexed: 05/09/2023]
Abstract
Floral scents act as long-distance signals to attract pollinators, but volatiles emitted from the vegetation and neighboring plant community may modify this mutualistic communication system. What impact does the olfactory background have on pollination systems and their evolution? We consider recent behavioral studies that address the context of when and where volatile backgrounds influence a pollinator's perception of floral blends. In parallel, we review neurophysiological studies that show the importance of blend composition and background in modifying the representation of floral blends in the pollinator brain, as well as experience-dependent plasticity in increasing the representation of a rewarding odor. Here, we suggest that the efficacy of the floral blend in different environments may be an important selective force shaping differences in pollinator olfactory receptor expression and underlying neural mechanisms that mediate flower visitation and plant reproductive isolation.
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Affiliation(s)
- Claire Rusch
- Department of Biology, University of Washington, Seattle, WA 98195, United States
| | - Geoffrey T Broadhead
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, United States
| | - Robert A Raguso
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, United States.
| | - Jeffrey A Riffell
- Department of Biology, University of Washington, Seattle, WA 98195, United States.
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Park IJ, Hein AM, Bobkov YV, Reidenbach MA, Ache BW, Principe JC. Neurally Encoding Time for Olfactory Navigation. PLoS Comput Biol 2016; 12:e1004682. [PMID: 26730727 PMCID: PMC4711578 DOI: 10.1371/journal.pcbi.1004682] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 11/30/2015] [Indexed: 11/19/2022] Open
Abstract
Accurately encoding time is one of the fundamental challenges faced by the nervous system in mediating behavior. We recently reported that some animals have a specialized population of rhythmically active neurons in their olfactory organs with the potential to peripherally encode temporal information about odor encounters. If these neurons do indeed encode the timing of odor arrivals, it should be possible to demonstrate that this capacity has some functional significance. Here we show how this sensory input can profoundly influence an animal’s ability to locate the source of odor cues in realistic turbulent environments—a common task faced by species that rely on olfactory cues for navigation. Using detailed data from a turbulent plume created in the laboratory, we reconstruct the spatiotemporal behavior of a real odor field. We use recurrence theory to show that information about position relative to the source of the odor plume is embedded in the timing between odor pulses. Then, using a parameterized computational model, we show how an animal can use populations of rhythmically active neurons to capture and encode this temporal information in real time, and use it to efficiently navigate to an odor source. Our results demonstrate that the capacity to accurately encode temporal information about sensory cues may be crucial for efficient olfactory navigation. More generally, our results suggest a mechanism for extracting and encoding temporal information from the sensory environment that could have broad utility for neural information processing. Many animals navigate turbulent environments using odor cues, a behavior known as olfactory search. We propose a neural mechanism for olfactory search based on evidence that a functional subset of olfactory receptor neurons (ORNs) called bursting ORNs or bORNs can encode the time intervals between successive encounters with odor. We show that these time intervals are estimators of the recurrence time, an information-rich statistic of the turbulent flow. Using a computational model parameterized with data from an actual turbulent plume, we demonstrate that a searcher can locate an odor source efficiently using only input from bORNs. These findings provide scientific evidence that the most important navigational information captured by the olfactory system may come in the form of measurements of time.
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Affiliation(s)
- In Jun Park
- Department of Electrical and Computer Engineering, University of Florida, Gainesville, Florida, United States of America
| | - Andrew M. Hein
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, United States of America
- * E-mail:
| | - Yuriy V. Bobkov
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, Florida, United States of America
- Center for Smell and Taste, and McKnight Brain Institute, University of Florida, Gainesville, Florida, United States of America
| | - Matthew A. Reidenbach
- Department of Environmental Sciences, University of Virginia, Charlottesville, Virginia, United States of America
| | - Barry W. Ache
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, Florida, United States of America
- Center for Smell and Taste, and McKnight Brain Institute, University of Florida, Gainesville, Florida, United States of America
- Departments of Biology and Neuroscience, University of Florida, Gainesville, Florida, United States of America
| | - Jose C. Principe
- Department of Electrical and Computer Engineering, University of Florida, Gainesville, Florida, United States of America
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Borges RM. On the Air: Broadcasting and Reception of Volatile Messages in Brood-Site Pollination Mutualisms. SIGNALING AND COMMUNICATION IN PLANTS 2016. [DOI: 10.1007/978-3-319-33498-1_10] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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40
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High-speed odor transduction and pulse tracking by insect olfactory receptor neurons. Proc Natl Acad Sci U S A 2014; 111:16925-30. [PMID: 25385618 DOI: 10.1073/pnas.1412051111] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Sensory systems encode both the static quality of a stimulus (e.g., color or shape) and its kinetics (e.g., speed and direction). The limits with which stimulus kinetics can be resolved are well understood in vision, audition, and somatosensation. However, the maximum temporal resolution of olfactory systems has not been accurately determined. Here, we probe the limits of temporal resolution in insect olfaction by delivering high frequency odor pulses and measuring sensory responses in the antennae. We show that transduction times and pulse tracking capabilities of olfactory receptor neurons are faster than previously reported. Once an odorant arrives at the boundary layer of the antenna, odor transduction can occur within less than 2 ms and fluctuating odor stimuli can be resolved at frequencies more than 100 Hz. Thus, insect olfactory receptor neurons can track stimuli of very short duration, as occur when their antennae encounter narrow filaments in an odor plume. These results provide a new upper bound to the kinetics of odor tracking in insect olfactory receptor neurons and to the latency of initial transduction events in olfaction.
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41
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Locatelli FF, Rela L. Mosaic activity patterns and their relation to perceptual similarity: open discussions on the molecular basis and circuitry of odor recognition. J Neurochem 2014; 131:546-53. [PMID: 25123415 DOI: 10.1111/jnc.12931] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 08/08/2014] [Accepted: 08/11/2014] [Indexed: 02/04/2023]
Abstract
Enormous advances have been made in the recent years in regard to the mechanisms and neural circuits by which odors are sensed and perceived. Part of this understanding has been gained from parallel studies in insects and rodents that show striking similarity in the mechanisms they use to sense, encode, and perceive odors. In this review, we provide a short introduction to the functioning of olfactory systems from transduction of odorant stimuli into electrical signals in sensory neurons to the anatomical and functional organization of the networks involved in neural representation of odors in the central nervous system. We make emphasis on the functional and anatomical architecture of the first synaptic relay of the olfactory circuit, the olfactory bulb in vertebrates and the antennal lobe in insects. We discuss how the exquisite and conserved architecture of this structure is established and how different odors are encoded in mosaic activity patterns. Finally, we discuss the validity of methods used to compare activation patterns in relation to perceptual similarity.
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Affiliation(s)
- Fernando F Locatelli
- Laboratorio de Neurobiología de la Memoria, Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, IFIByNE-CONICET, Argentina
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42
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Martinez D, Arhidi L, Demondion E, Masson JB, Lucas P. Using insect electroantennogram sensors on autonomous robots for olfactory searches. J Vis Exp 2014:e51704. [PMID: 25145980 PMCID: PMC4692349 DOI: 10.3791/51704] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Robots designed to track chemical leaks in hazardous industrial facilities or explosive traces in landmine fields face the same problem as insects foraging for food or searching for mates: the olfactory search is constrained by the physics of turbulent transport. The concentration landscape of wind borne odors is discontinuous and consists of sporadically located patches. A pre-requisite to olfactory search is that intermittent odor patches are detected. Because of its high speed and sensitivity, the olfactory organ of insects provides a unique opportunity for detection. Insect antennae have been used in the past to detect not only sex pheromones but also chemicals that are relevant to humans, e.g., volatile compounds emanating from cancer cells or toxic and illicit substances. We describe here a protocol for using insect antennae on autonomous robots and present a proof of concept for tracking odor plumes to their source. The global response of olfactory neurons is recorded in situ in the form of electroantennograms (EAGs). Our experimental design, based on a whole insect preparation, allows stable recordings within a working day. In comparison, EAGs on excised antennae have a lifetime of 2 hr. A custom hardware/software interface was developed between the EAG electrodes and a robot. The measurement system resolves individual odor patches up to 10 Hz, which exceeds the time scale of artificial chemical sensors. The efficiency of EAG sensors for olfactory searches is further demonstrated in driving the robot toward a source of pheromone. By using identical olfactory stimuli and sensors as in real animals, our robotic platform provides a direct means for testing biological hypotheses about olfactory coding and search strategies. It may also prove beneficial for detecting other odorants of interests by combining EAGs from different insect species in a bioelectronic nose configuration or using nanostructured gas sensors that mimic insect antennae.
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Affiliation(s)
- Dominique Martinez
- UMR 7503, Laboratoire Lorrain de Recherche en Informatique et ses Applications (LORIA), Centre National de la Recherche Scientifique (CNRS);
| | - Lotfi Arhidi
- UMR 7503, Laboratoire Lorrain de Recherche en Informatique et ses Applications (LORIA), Centre National de la Recherche Scientifique (CNRS)
| | - Elodie Demondion
- UMR 1392 iEES-Paris, Institut d'Ecologie et des Sciences de l'Environnement de Paris
| | | | - Philippe Lucas
- UMR 1392 iEES-Paris, Institut d'Ecologie et des Sciences de l'Environnement de Paris
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Afify A, Horlacher B, Roller J, Galizia CG. Different repellents for Aedes aegypti against blood-feeding and oviposition. PLoS One 2014; 9:e103765. [PMID: 25079819 PMCID: PMC4117642 DOI: 10.1371/journal.pone.0103765] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Accepted: 07/04/2014] [Indexed: 11/18/2022] Open
Abstract
Methyl N,N-dimethyl anthranilate (MDA), ethyl anthranilate (EA) and butyl anthranilate (BA) were previously shown to repel Aedes aegypti mosquitoes from landing on human skin. However, the effect of these compounds on the orientation of flying mosquitoes in a choice situation and their effect on mosquito oviposition are not yet known. Here, we used a modified Y-tube olfactometer to test the effect of these compounds on the orientation of Aedes aegypti flying towards skin odor (human fingers), and we tested their effect on Aedes aegypti oviposition choice in a cage assay. In both behavioral situations we compared the effect to the well-documented repellent N,N-diethyl-meta-toluamide (DEET). MDA, EA, and DEET inhibited Aedes aegypti from flying towards skin odor while BA had no such effect. Conversely, MDA had no effect on oviposition while EA, BA, and DEET deterred oviposition, with the strongest effect observed for BA. Thus, we confirm that EA and DEET are generally repellent, while MDA is repellent only in a host-seeking context, and BA is deterrent only in an oviposition context. These compounds appear of potential use in mosquito control programs.
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Affiliation(s)
- Ali Afify
- Neurobiology, University of Konstanz, Konstanz, Germany
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44
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Affiliation(s)
- Paul Szyszka
- Department of Neurobiology, University of Konstanz, 78457 Konstanz, Germany.
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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: 109] [Impact Index Per Article: 10.9] [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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Galizia CG. Olfactory coding in the insect brain: data and conjectures. Eur J Neurosci 2014; 39:1784-95. [PMID: 24698302 PMCID: PMC4237541 DOI: 10.1111/ejn.12558] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 02/11/2014] [Accepted: 02/13/2014] [Indexed: 11/28/2022]
Abstract
Much progress has been made recently in understanding how olfactory coding works in insect brains. Here, I propose a wiring diagram for the major steps from the first processing network (the antennal lobe) to behavioral readout. I argue that the sequence of lateral inhibition in the antennal lobe, non-linear synapses, threshold-regulating gated spring network, selective lateral inhibitory networks across glomeruli, and feedforward inhibition to the lateral protocerebrum cover most of the experimental results from different research groups and model species. I propose that the main difference between mushroom bodies and the lateral protocerebrum is not about learned vs. innate behavior. Rather, mushroom bodies perform odor identification, whereas the lateral protocerebrum performs odor evaluation (both learned and innate). I discuss the concepts of labeled line and combinatorial coding and postulate that, under restrictive experimental conditions, these networks lead to an apparent existence of 'labeled line' coding for special odors. Modulatory networks are proposed as switches between different evaluating systems in the lateral protocerebrum. A review of experimental data and theoretical conjectures both contribute to this synthesis, creating new hypotheses for future research.
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Szyszka P, Stierle JS. Mixture processing and odor-object segregation in insects. PROGRESS IN BRAIN RESEARCH 2014; 208:63-85. [PMID: 24767479 DOI: 10.1016/b978-0-444-63350-7.00003-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
When enjoying the scent of grinded coffee or cut grass, most of us are unaware that these scents consist of up to hundreds of volatile substances. We perceive these odorant mixtures as a unitary scent rather than a combination of multiple odorants. The olfactory system processes odor mixtures into meaningful odor objects to provide animals with information that is relevant in everyday tasks, such as habitat localization, foraging, social communication, reproduction, and orientation. For example, odor objects can be a particular flower species on which a bee feeds or the receptive female moth which attracts males by its specific pheromone blend. Using odor mixtures as cues for odor-driven behavior rather than single odorants allows unambiguous identification of a potentially infinite number of odor objects. When multiple odor objects are present at the same time, they form a temporally complex mixture. In order to segregate this mixture into its meaningful constituents, animals must have evolved odor-object segregation mechanisms which are robust against the interference by background odors. In this review, we describe how insects use information of the olfactory environment to either bind odorants into unitary percepts or to segregate them from each other.
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Affiliation(s)
- Paul Szyszka
- Department of Biology-Neurobiology, University of Konstanz, Konstanz, Germany.
| | - Jacob S Stierle
- Department of Biology-Neurobiology, University of Konstanz, Konstanz, Germany
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Auffarth B. Understanding smell—The olfactory stimulus problem. Neurosci Biobehav Rev 2013; 37:1667-79. [DOI: 10.1016/j.neubiorev.2013.06.009] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Revised: 05/09/2013] [Accepted: 06/13/2013] [Indexed: 01/30/2023]
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Nowotny T, Galizia CG, Szyszka P. Data-driven honeybee antennal lobe model demonstrates how stimulus-onset asynchrony can aid odor segregation. BMC Neurosci 2013. [PMCID: PMC3704718 DOI: 10.1186/1471-2202-14-s1-p378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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