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Nag A, van Breugel F. Odour source distance is predictable from a time history of odour statistics for large scale outdoor plumes. J R Soc Interface 2024; 21:20240169. [PMID: 39079675 PMCID: PMC11288670 DOI: 10.1098/rsif.2024.0169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Accepted: 05/23/2024] [Indexed: 08/02/2024] Open
Abstract
Odour plumes in turbulent environments are intermittent and sparse. Laboratory-scaled experiments suggest that information about the source distance may be encoded in odour signal statistics, yet it is unclear whether useful and continuous distance estimates can be made under real-world flow conditions. Here, we analyse odour signals from outdoor experiments with a sensor moving across large spatial scales in desert and forest environments to show that odour signal statistics can yield useful estimates of distance. We show that achieving accurate estimates of distance requires integrating statistics from 5 to 10 s, with a high temporal encoding of the olfactory signal of at least 20 Hz. By combining distance estimates from a linear model with wind-relative motion dynamics, we achieved source distance estimates in a 60 × 60 m2 search area with median errors of 3-8 m, a distance at which point odour sources are often within visual range for animals such as mosquitoes.
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Affiliation(s)
- Arunava Nag
- Computer Science Engineering Department, University of Nevada, Reno, NV, USA
| | - Floris van Breugel
- Integrative Neuroscience Program, University of Nevada, Reno, NV, USA
- Ecology Evolution and Conservation Biology Program, University of Nevada, Reno, NV, USA
- Department of Mechanical Engineering, University of Nevada, Reno, NV, USA
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2
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Lewis SM, Suarez LM, Rigolli N, Franks KM, Steinmetz NA, Gire DH. The spiking output of the mouse olfactory bulb encodes large-scale temporal features of natural odor environments. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.01.582978. [PMID: 38496526 PMCID: PMC10942328 DOI: 10.1101/2024.03.01.582978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
In natural odor environments, odor travels in plumes. Odor concentration dynamics change in characteristic ways across the width and length of a plume. Thus, spatiotemporal dynamics of plumes have informative features for animals navigating to an odor source. Population activity in the olfactory bulb (OB) has been shown to follow odor concentration across plumes to a moderate degree (Lewis et al., 2021). However, it is unknown whether the ability to follow plume dynamics is driven by individual cells or whether it emerges at the population level. Previous research has explored the responses of individual OB cells to isolated features of plumes, but it is difficult to adequately sample the full feature space of plumes as it is still undetermined which features navigating mice employ during olfactory guided search. Here we released odor from an upwind odor source and simultaneously recorded both odor concentration dynamics and cellular response dynamics in awake, head-fixed mice. We found that longer timescale features of odor concentration dynamics were encoded at both the cellular and population level. At the cellular level, responses were elicited at the beginning of the plume for each trial, signaling plume onset. Plumes with high odor concentration elicited responses at the end of the plume, signaling plume offset. Although cellular level tracking of plume dynamics was observed to be weak, we found that at the population level, OB activity distinguished whiffs and blanks (accurately detected odor presence versus absence) throughout the duration of a plume. Even ~20 OB cells were enough to accurately discern odor presence throughout a plume. Our findings indicate that the full range of odor concentration dynamics and high frequency fluctuations are not encoded by OB spiking activity. Instead, relatively lower-frequency temporal features of plumes, such as plume onset, plume offset, whiffs, and blanks, are represented in the OB.
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Affiliation(s)
- Suzanne M. Lewis
- Department of Psychology, University of Washington, Seattle, WA, United States
- Department of Neurobiology, Duke University, Durham, NC, USA
| | - Lucas M. Suarez
- Department of Psychology, University of Washington, Seattle, WA, United States
| | - Nicola Rigolli
- Laboratoire de Physique, École Normale Supérieure (LPENS), Paris, France
| | - Kevin M. Franks
- Department of Neurobiology, Duke University, Durham, NC, USA
| | - Nicholas A. Steinmetz
- Department of Biological Structure, University of Washington, Seattle, WA, United States
| | - David H. Gire
- Department of Psychology, University of Washington, Seattle, WA, United States
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3
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Choi K, Rosenbluth W, Graf IR, Kadakia N, Emonet T. Bifurcation enhances temporal information encoding in the olfactory periphery. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.27.596086. [PMID: 38853849 PMCID: PMC11160621 DOI: 10.1101/2024.05.27.596086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
Living systems continually respond to signals from the surrounding environment. Survival requires that their responses adapt quickly and robustly to the changes in the environment. One particularly challenging example is olfactory navigation in turbulent plumes, where animals experience highly intermittent odor signals while odor concentration varies over many length- and timescales. Here, we show theoretically that Drosophila olfactory receptor neurons (ORNs) can exploit proximity to a bifurcation point of their firing dynamics to reliably extract information about the timing and intensity of fluctuations in the odor signal, which have been shown to be critical for odor-guided navigation. Close to the bifurcation, the system is intrinsically invariant to signal variance, and information about the timing, duration, and intensity of odor fluctuations is transferred efficiently. Importantly, we find that proximity to the bifurcation is maintained by mean adaptation alone and therefore does not require any additional feedback mechanism or fine-tuning. Using a biophysical model with calcium-based feedback, we demonstrate that this mechanism can explain the measured adaptation characteristics of Drosophila ORNs.
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4
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Choi K, Rosenbluth W, Graf IR, Kadakia N, Emonet T. Bifurcation enhances temporal information encoding in the olfactory periphery. ARXIV 2024:arXiv:2405.20135v2. [PMID: 38855541 PMCID: PMC11160886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
Living systems continually respond to signals from the surrounding environment. Survival requires that their responses adapt quickly and robustly to the changes in the environment. One particularly challenging example is olfactory navigation in turbulent plumes, where animals experience highly intermittent odor signals while odor concentration varies over many length- and timescales. Here, we show theoretically that Drosophila olfactory receptor neurons (ORNs) can exploit proximity to a bifurcation point of their firing dynamics to reliably extract information about the timing and intensity of fluctuations in the odor signal, which have been shown to be critical for odor-guided navigation. Close to the bifurcation, the system is intrinsically invariant to signal variance, and information about the timing, duration, and intensity of odor fluctuations is transferred efficiently. Importantly, we find that proximity to the bifurcation is maintained by mean adaptation alone and therefore does not require any additional feedback mechanism or fine-tuning. Using a biophysical model with calcium-based feedback, we demonstrate that this mechanism can explain the measured adaptation characteristics of Drosophila ORNs.
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Affiliation(s)
- Kiri Choi
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut 06511, USA
- Quantitative Biology Institute, Yale University, New Haven, Connecticut 06511, USA
- Swartz Foundation for Theoretical Neuroscience, Yale University, New Haven, Connecticut 06511, USA
| | - Will Rosenbluth
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut 06511, USA
| | - Isabella R. Graf
- Quantitative Biology Institute, Yale University, New Haven, Connecticut 06511, USA
- Department of Physics, Yale University, New Haven, Connecticut 06511, USA
| | - Nirag Kadakia
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut 06511, USA
- Quantitative Biology Institute, Yale University, New Haven, Connecticut 06511, USA
- Swartz Foundation for Theoretical Neuroscience, Yale University, New Haven, Connecticut 06511, USA
| | - Thierry Emonet
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut 06511, USA
- Quantitative Biology Institute, Yale University, New Haven, Connecticut 06511, USA
- Department of Physics, Yale University, New Haven, Connecticut 06511, USA
- Interdepartmental Neuroscience Program, Yale University, New Haven, Connecticut 06511, USA
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5
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Ma T, Hermundstad AM. A vast space of compact strategies for effective decisions. SCIENCE ADVANCES 2024; 10:eadj4064. [PMID: 38905348 PMCID: PMC11192086 DOI: 10.1126/sciadv.adj4064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 05/15/2024] [Indexed: 06/23/2024]
Abstract
Inference-based decision-making, which underlies a broad range of behavioral tasks, is typically studied using a small number of handcrafted models. We instead enumerate a complete ensemble of strategies that could be used to effectively, but not necessarily optimally, solve a dynamic foraging task. Each strategy is expressed as a behavioral "program" that uses a limited number of internal states to specify actions conditioned on past observations. We show that the ensemble of strategies is enormous-comprising a quarter million programs with up to five internal states-but can nevertheless be understood in terms of algorithmic "mutations" that alter the structure of individual programs. We devise embedding algorithms that reveal how mutations away from a Bayesian-like strategy can diversify behavior while preserving performance, and we construct a compositional description to link low-dimensional changes in algorithmic structure with high-dimensional changes in behavior. Together, this work provides an alternative approach for understanding individual variability in behavior across animals and tasks.
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Affiliation(s)
- Tzuhsuan Ma
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Ann M. Hermundstad
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
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6
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Gumaste A, Baker KL, Izydorczak M, True AC, Vasan G, Crimaldi JP, Verhagen J. Behavioral discrimination and olfactory bulb encoding of odor plume intermittency. eLife 2024; 13:e85303. [PMID: 38441541 PMCID: PMC11001298 DOI: 10.7554/elife.85303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 03/04/2024] [Indexed: 04/09/2024] Open
Abstract
In order to survive, animals often need to navigate a complex odor landscape where odors can exist in airborne plumes. Several odor plume properties change with distance from the odor source, providing potential navigational cues to searching animals. Here, we focus on odor intermittency, a temporal odor plume property that measures the fraction of time odor is above a threshold at a given point within the plume and decreases with increasing distance from the odor source. We sought to determine if mice can use changes in intermittency to locate an odor source. To do so, we trained mice on an intermittency discrimination task. We establish that mice can discriminate odor plume samples of low and high intermittency and that the neural responses in the olfactory bulb can account for task performance and support intermittency encoding. Modulation of sniffing, a behavioral parameter that is highly dynamic during odor-guided navigation, affects both behavioral outcome on the intermittency discrimination task and neural representation of intermittency. Together, this work demonstrates that intermittency is an odor plume property that can inform olfactory search and more broadly supports the notion that mammalian odor-based navigation can be guided by temporal odor plume properties.
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Affiliation(s)
- Ankita Gumaste
- Interdepartmental Neuroscience Program, Yale UniversityNew HavenUnited States
- John B. Pierce LaboratoryNew HavenUnited States
- Department of Neuroscience, Yale School of MedicineNew HavenUnited States
| | - Keeley L Baker
- John B. Pierce LaboratoryNew HavenUnited States
- Department of Neuroscience, Yale School of MedicineNew HavenUnited States
| | | | - Aaron C True
- Department of Civil, Environmental and Architectural Engineering, University of ColoradoBoulderUnited States
| | | | - John P Crimaldi
- Department of Civil, Environmental and Architectural Engineering, University of ColoradoBoulderUnited States
| | - Justus Verhagen
- Interdepartmental Neuroscience Program, Yale UniversityNew HavenUnited States
- John B. Pierce LaboratoryNew HavenUnited States
- Department of Neuroscience, Yale School of MedicineNew HavenUnited States
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7
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Ryan C, Martins MCI, Healy K, Bejder L, Cerchio S, Christiansen F, Durban J, Fearnbach H, Fortune S, Friedlaender A, Koski WR, Miller C, Rodríguez-González FM, Segre PS, Urbán R J, Vivier F, Weir CR, Moore MJ. Morphology of nares associated with stereo-olfaction in baleen whales. Biol Lett 2024; 20:20230479. [PMID: 38290551 PMCID: PMC10827433 DOI: 10.1098/rsbl.2023.0479] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 01/04/2024] [Indexed: 02/01/2024] Open
Abstract
The sensory mechanisms used by baleen whales (Mysticeti) for locating ephemeral, dense prey patches in vast marine habitats are poorly understood. Baleen whales have a functional olfactory system with paired rather than single blowholes (nares), potentially enabling stereo-olfaction. Dimethyl sulfide (DMS) is an odorous gas emitted by phytoplankton in response to grazing by zooplankton. Some seabirds use DMS to locate prey, but this ability has not been demonstrated in whales. For 14 extant species of baleen whale, nares morphometrics (imagery from unoccupied aerial systems, UAS) was related to published trophic level indices using Bayesian phylogenetic mixed modelling. A significant negative relationship was found between nares width and whale trophic level (β = -0.08, lower 95% CI = -0.13, upper 95% CI = -0.03), corresponding with a 39% increase in nares width from highest to lowest trophic level. Thus, species with nasal morphology best suited to stereo-olfaction are more zooplanktivorous. These findings provide evidence that some baleen whale species may be able to localize odorants e.g. DMS. Our results help direct future behavioural trials of olfaction in baleen whales, by highlighting the most appropriate species to study. This is a research priority, given the potential for DMS-mediated plastic ingestion by whales.
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Affiliation(s)
- Conor Ryan
- Scottish Association for Marine Science, Argyll PA37 1QA, UK
| | - Maria C. I. Martins
- Sea Mammal Research Unit, Scottish Oceans Institute, School of Biology, University of St Andrews, East Sands KY16 8LB, UK
| | - Kevin Healy
- Zoology Department, School of Natural Sciences, National University of Ireland Galway, Galway H91 TK33, Ireland
| | - Lars Bejder
- Marine Mammal Research Program, Hawai'i Institute of Marine Biology, University of Hawai‘i at Mānoa, Kāne'ohe, Hawai'i, USA
| | - Salvatore Cerchio
- African Aquatic Conservation Fund, P.O. Box 366, Chilmark, MA 02535, USA
| | - Fredrik Christiansen
- Marine Mammal Research, Department of Ecoscience, Aarhus University, 4000 Roskilde, Denmark
| | - John Durban
- SR3, SeaLife Response, Rehabilitation and Research, Des Moines, WA, USA
| | - Holly Fearnbach
- SR3, SeaLife Response, Rehabilitation and Research, Des Moines, WA, USA
| | - Sarah Fortune
- Department of Oceanography, Dalhousie University, Halifax, NS, Canada
| | - Ari Friedlaender
- Institute of Marine Sciences, University of California, Santa Cruz, Santa Cruz, CA, USA
| | - William R. Koski
- LGL Limited Environmental Research Associates, 22 Fisher Street, King City, Ontario, Canada, L7B 1A6
| | - Carolyn Miller
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | | | - Paolo S. Segre
- Department of Natural and Applied Sciences, University of Wisconsin, Green Bay, WI, USA
- Hopkins Marine Station, Oceans Department, Stanford University, Stanford, CA, USA
| | - Jorge Urbán R
- Departamento de Ciencias Marinas y Costeras, Universidad Autónoma de Baja California Sur, La Paz, BCS, México
| | - Fabien Vivier
- Marine Mammal Research Program, Hawai'i Institute of Marine Biology, University of Hawai‘i at Mānoa, Kāne'ohe, Hawai'i, USA
| | - Caroline R. Weir
- Falklands Conservation, Jubilee Villas, 41 Ross Road, Stanley, Falkland Islands
| | - Michael J. Moore
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
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8
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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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9
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Chen KS, Wu R, Gershow MH, Leifer AM. Continuous odor profile monitoring to study olfactory navigation in small animals. eLife 2023; 12:e85910. [PMID: 37489570 PMCID: PMC10425172 DOI: 10.7554/elife.85910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 07/21/2023] [Indexed: 07/26/2023] Open
Abstract
Olfactory navigation is observed across species and plays a crucial role in locating resources for survival. In the laboratory, understanding the behavioral strategies and neural circuits underlying odor-taxis requires a detailed understanding of the animal's sensory environment. For small model organisms like Caenorhabditis elegans and larval Drosophila melanogaster, controlling and measuring the odor environment experienced by the animal can be challenging, especially for airborne odors, which are subject to subtle effects from airflow, temperature variation, and from the odor's adhesion, adsorption, or reemission. Here, we present a method to control and measure airborne odor concentration in an arena compatible with an agar substrate. Our method allows continuous controlling and monitoring of the odor profile while imaging animal behavior. We construct stationary chemical landscapes in an odor flow chamber through spatially patterned odorized air. The odor concentration is measured with a spatially distributed array of digital gas sensors. Careful placement of the sensors allows the odor concentration across the arena to be continuously inferred in space and monitored through time. We use this approach to measure the odor concentration that each animal experiences as it undergoes chemotaxis behavior and report chemotaxis strategies for C. elegans and D. melanogaster larvae populations as they navigate spatial odor landscapes.
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Affiliation(s)
- Kevin S Chen
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
| | - Rui Wu
- Department of Physics, New York UniversityNew YorkUnited States
| | - Marc H Gershow
- Department of Physics, New York UniversityNew YorkUnited States
- Center for Neural Science, New York UniversityNew YorkUnited States
| | - Andrew M Leifer
- Princeton Neuroscience Institute, Princeton UniversityPrincetonUnited States
- Department of Physics, Princeton UniversityPrincetonUnited States
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10
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Jayaram V, Sehdev A, Kadakia N, Brown EA, Emonet T. Temporal novelty detection and multiple timescale integration drive Drosophila orientation dynamics in temporally diverse olfactory environments. PLoS Comput Biol 2023; 19:e1010606. [PMID: 37167321 DOI: 10.1371/journal.pcbi.1010606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 05/23/2023] [Accepted: 04/03/2023] [Indexed: 05/13/2023] Open
Abstract
To survive, insects must effectively navigate odors plumes to their source. In natural plumes, turbulent winds break up smooth odor regions into disconnected patches, so navigators encounter brief bursts of odor interrupted by bouts of clean air. The timing of these encounters plays a critical role in navigation, determining the direction, rate, and magnitude of insects' orientation and speed dynamics. Disambiguating the specific role of odor timing from other cues, such as spatial structure, is challenging due to natural correlations between plumes' temporal and spatial features. Here, we use optogenetics to isolate temporal features of odor signals, examining how the frequency and duration of odor encounters shape the navigational decisions of freely-walking Drosophila. We find that fly angular velocity depends on signal frequency and intermittency-the fraction of time signal can be detected-but not directly on durations. Rather than switching strategies when signal statistics change, flies smoothly transition between signal regimes, by combining an odor offset response with a frequency-dependent novelty-like response. In the latter, flies are more likely to turn in response to each odor hit only when the hits are sparse. Finally, the upwind bias of individual turns relies on a filtering scheme with two distinct timescales, allowing rapid and sustained responses in a variety of signal statistics. A quantitative model incorporating these ingredients recapitulates fly orientation dynamics across a wide range of environments and shows that temporal novelty detection, when combined with odor motion detection, enhances odor plume navigation.
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Affiliation(s)
- Viraaj Jayaram
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut, United States of America
- Quantitative Biology Institute, Yale University, New Haven, Connecticut, United States of America
- Department of Physics, Yale University, New Haven, Connecticut, United States of America
| | - Aarti Sehdev
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut, United States of America
- Quantitative Biology Institute, Yale University, New Haven, Connecticut, United States of America
| | - Nirag Kadakia
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut, United States of America
- Quantitative Biology Institute, Yale University, New Haven, Connecticut, United States of America
- Swartz Foundation for Theoretical Neuroscience, Yale University, New Haven, Connecticut, United States of America
| | - Ethan A Brown
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut, United States of America
- Quantitative Biology Institute, Yale University, New Haven, Connecticut, United States of America
- Yale College, Yale University, New Haven, Connecticut, United States of America
| | - Thierry Emonet
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut, United States of America
- Quantitative Biology Institute, Yale University, New Haven, Connecticut, United States of America
- Department of Physics, Yale University, New Haven, Connecticut, United States of America
- Interdepartmental Neuroscience Program, Yale University, New Haven, Connecticut, United States of America
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11
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Heinonen RA, Biferale L, Celani A, Vergassola M. Optimal policies for Bayesian olfactory search in turbulent flows. Phys Rev E 2023; 107:055105. [PMID: 37329026 DOI: 10.1103/physreve.107.055105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 03/27/2023] [Indexed: 06/18/2023]
Abstract
In many practical scenarios, a flying insect must search for the source of an emitted cue which is advected by the atmospheric wind. On the macroscopic scales of interest, turbulence tends to mix the cue into patches of relatively high concentration over a background of very low concentration, so that the insect will detect the cue only intermittently and cannot rely on chemotactic strategies which simply climb the concentration gradient. In this work we cast this search problem in the language of a partially observable Markov decision process and use the Perseus algorithm to compute strategies that are near-optimal with respect to the arrival time. We test the computed strategies on a large two-dimensional grid, present the resulting trajectories and arrival time statistics, and compare these to the corresponding results for several heuristic strategies, including (space-aware) infotaxis, Thompson sampling, and QMDP. We find that the near-optimal policy found by our implementation of Perseus outperforms all heuristics we test by several measures. We use the near-optimal policy to study how the search difficulty depends on the starting location. We also discuss the choice of initial belief and the robustness of the policies to changes in the environment. Finally, we present a detailed and pedagogical discussion about the implementation of the Perseus algorithm, including the benefits-and pitfalls-of employing a reward-shaping function.
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Affiliation(s)
- R A Heinonen
- Department of Physics and INFN, University of Rome "Tor Vergata," Via della Ricerca Scientifica 1, 00133 Rome, Italy
| | - L Biferale
- Department of Physics and INFN, University of Rome "Tor Vergata," Via della Ricerca Scientifica 1, 00133 Rome, Italy
| | - A Celani
- Quantitative Life Sciences, Abdus Salam International Centre for Theoretical Physics, 34151 Trieste, Italy
| | - M Vergassola
- Laboratoire de Physique, École Normale Supérieure, CNRS, PSL Research University, Sorbonne University, 75005 Paris, France
- Department of Physics, University of California San Diego, La Jolla, California 92093, USA
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12
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Wechsler SP, Bhandawat V. Behavioral algorithms and neural mechanisms underlying odor-modulated locomotion in insects. J Exp Biol 2023; 226:jeb200261. [PMID: 36637433 PMCID: PMC10086387 DOI: 10.1242/jeb.200261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Odors released from mates and resources such as a host and food are often the first sensory signals that an animal can detect. Changes in locomotion in response to odors are an important mechanism by which animals access resources important to their survival. Odor-modulated changes in locomotion in insects constitute a whole suite of flexible behaviors that allow insects to close in on these resources from long distances and perform local searches to locate and subsequently assess them. Here, we review changes in odor-mediated locomotion across many insect species. We emphasize that changes in locomotion induced by odors are diverse. In particular, the olfactory stimulus is sporadic at long distances and becomes more continuous at short distances. This distance-dependent change in temporal profile produces a corresponding change in an insect's locomotory strategy. We also discuss the neural circuits underlying odor modulation of locomotion.
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Affiliation(s)
- Samuel P. Wechsler
- School of Biomedical Engineering, Sciences and Health Systems, Drexel University, Philadelphia, PA 19104, USA
| | - Vikas Bhandawat
- School of Biomedical Engineering, Sciences and Health Systems, Drexel University, Philadelphia, PA 19104, USA
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13
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Jacobs LF. The PROUST hypothesis: the embodiment of olfactory cognition. Anim Cogn 2023; 26:59-72. [PMID: 36542172 PMCID: PMC9877075 DOI: 10.1007/s10071-022-01734-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 11/20/2022] [Accepted: 12/06/2022] [Indexed: 12/24/2022]
Abstract
The extension of cognition beyond the brain to the body and beyond the body to the environment is an area of debate in philosophy and the cognitive sciences. Yet, these debates largely overlook olfaction, a sensory modality used by most animals. Here, I use the philosopher's framework to explore the implications of embodiment for olfactory cognition. The philosopher's 4E framework comprises embodied cognition, emerging from a nervous system characterized by its interactions with its body. The necessity of action for perception adds enacted cognition. Cognition is further embedded in the sensory inputs of the individual and is extended beyond the individual to information stored in its physical and social environments. Further, embodiment must fulfill the criterion of mutual manipulability, where an agent's cognitive state is involved in continual, reciprocal influences with its environment. Cognition cannot be understood divorced from evolutionary history, however, and I propose adding evolved, as a fifth term to the 4E framework. We must, therefore, begin at the beginning, with chemosensation, a sensory modality that underlies purposive behavior, from bacteria to humans. The PROUST hypothesis (perceiving and reconstructing odor utility in space and time) describers how olfaction, this ancient scaffold and common denominator of animal cognition, fulfills the criteria of embodied cognition. Olfactory cognition, with its near universal taxonomic distribution as well as the near absence of conscious representation in humans, may offer us the best sensorimotor system for the study of embodiment.
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Affiliation(s)
- Lucia F. Jacobs
- Department of Psychology, University of California, Berkeley, 2121 Berkeley Way, Berkeley, CA 94720-1650 USA
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14
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Kadakia N, Demir M, Michaelis BT, DeAngelis BD, Reidenbach MA, Clark DA, Emonet T. Odour motion sensing enhances navigation of complex plumes. Nature 2022; 611:754-761. [PMID: 36352224 PMCID: PMC10039482 DOI: 10.1038/s41586-022-05423-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 10/06/2022] [Indexed: 11/11/2022]
Abstract
Odour plumes in the wild are spatially complex and rapidly fluctuating structures carried by turbulent airflows1-4. To successfully navigate plumes in search of food and mates, insects must extract and integrate multiple features of the odour signal, including odour identity5, intensity6 and timing6-12. Effective navigation requires balancing these multiple streams of olfactory information and integrating them with other sensory inputs, including mechanosensory and visual cues9,12,13. Studies dating back a century have indicated that, of these many sensory inputs, the wind provides the main directional cue in turbulent plumes, leading to the longstanding model of insect odour navigation as odour-elicited upwind motion6,8-12,14,15. Here we show that Drosophila melanogaster shape their navigational decisions using an additional directional cue-the direction of motion of odours-which they detect using temporal correlations in the odour signal between their two antennae. Using a high-resolution virtual-reality paradigm to deliver spatiotemporally complex fictive odours to freely walking flies, we demonstrate that such odour-direction sensing involves algorithms analogous to those in visual-direction sensing16. Combining simulations, theory and experiments, we show that odour motion contains valuable directional information that is absent from the airflow alone, and that both Drosophila and virtual agents are aided by that information in navigating naturalistic plumes. The generality of our findings suggests that odour-direction sensing may exist throughout the animal kingdom and could improve olfactory robot navigation in uncertain environments.
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Affiliation(s)
- Nirag Kadakia
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
- Quantitative Biology Institute, Yale University, New Haven, CT, USA
- Swartz Foundation for Theoretical Neuroscience, Yale University, New Haven, CT, USA
| | - Mahmut Demir
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
- Quantitative Biology Institute, Yale University, New Haven, CT, USA
| | - Brenden T Michaelis
- Department of Environmental Sciences, University of Virginia, Charlottesville, VA, USA
| | - Brian D DeAngelis
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
- Quantitative Biology Institute, Yale University, New Haven, CT, USA
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT, USA
| | - Matthew A Reidenbach
- Department of Environmental Sciences, University of Virginia, Charlottesville, VA, USA
| | - Damon A Clark
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA.
- Quantitative Biology Institute, Yale University, New Haven, CT, USA.
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT, USA.
- Department of Physics, Yale University, New Haven, CT, USA.
| | - Thierry Emonet
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA.
- Quantitative Biology Institute, Yale University, New Haven, CT, USA.
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT, USA.
- Department of Physics, Yale University, New Haven, CT, USA.
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15
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Rigolli N, Magnoli N, Rosasco L, Seminara A. Learning to predict target location with turbulent odor plumes. eLife 2022; 11:72196. [PMID: 35959726 PMCID: PMC9374438 DOI: 10.7554/elife.72196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 07/18/2022] [Indexed: 11/13/2022] Open
Abstract
Animal behavior and neural recordings show that the brain is able to measure both the intensity and the timing of odor encounters. However, whether intensity or timing of odor detections is more informative for olfactory-driven behavior is not understood. To tackle this question, we consider the problem of locating a target using the odor it releases. We ask whether the position of a target is best predicted by measures of timing vs intensity of its odor, sampled for a short period of time. To answer this question, we feed data from accurate numerical simulations of odor transport to machine learning algorithms that learn how to connect odor to target location. We find that both intensity and timing can separately predict target location even from a distance of several meters; however, their efficacy varies with the dilution of the odor in space. Thus, organisms that use olfaction from different ranges may have to switch among different modalities. This has implications on how the brain should represent odors as the target is approached. We demonstrate simple strategies to improve accuracy and robustness of the prediction by modifying odor sampling and appropriately combining distinct measures together. To test the predictions, animal behavior and odor representation should be monitored as the animal moves relative to the target, or in virtual conditions that mimic concentrated vs dilute environments.
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Affiliation(s)
- Nicola Rigolli
- Department of Physics, University of Genova, Genova, Italy.,Institut de Physique de Nice, Université Côte d'Azur, Centre National de la Recherche Scientifique, Nice, France.,National Institute of Nuclear Physics, Genova, Italy.,MalGa, Department of Civil, Chemical and Environmental Engineering, University of Genoa, Genoa, Italy
| | - Nicodemo Magnoli
- Department of Physics, University of Genova, Genova, Italy.,National Institute of Nuclear Physics, Genova, Italy
| | - Lorenzo Rosasco
- MaLGa, Department of computer science, bioengineering, robotics and systems engineering, University of Genova, Genova, Italy
| | - Agnese Seminara
- Institut de Physique de Nice, Université Côte d'Azur, Centre National de la Recherche Scientifique, Nice, France.,MalGa, Department of Civil, Chemical and Environmental Engineering, University of Genoa, Genoa, Italy
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16
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Jacobs LF. How the evolution of air breathing shaped hippocampal function. Philos Trans R Soc Lond B Biol Sci 2022; 377:20200532. [PMID: 34957846 PMCID: PMC8710879 DOI: 10.1098/rstb.2020.0532] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 11/15/2021] [Indexed: 12/25/2022] Open
Abstract
To make maps from airborne odours requires dynamic respiratory patterns. I propose that this constraint explains the modulation of memory by nasal respiration in mammals, including murine rodents (e.g. laboratory mouse, laboratory rat) and humans. My prior theories of limbic system evolution offer a framework to understand why this occurs. The answer begins with the evolution of nasal respiration in Devonian lobe-finned fishes. This evolutionary innovation led to adaptive radiations in chemosensory systems, including the emergence of the vomeronasal system and a specialization of the main olfactory system for spatial orientation. As mammals continued to radiate into environments hostile to spatial olfaction (air, water), there was a loss of hippocampal structure and function in lineages that evolved sensory modalities adapted to these new environments. Hence the independent evolution of echolocation in bats and toothed whales was accompanied by a loss of hippocampal structure (whales) and an absence of hippocampal theta oscillations during navigation (bats). In conclusion, models of hippocampal function that are divorced from considerations of ecology and evolution fall short of explaining hippocampal diversity across mammals and even hippocampal function in humans. This article is part of the theme issue 'Systems neuroscience through the lens of evolutionary theory'.
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Affiliation(s)
- Lucia F. Jacobs
- Department of Psychology, University of California, 2121 Berkeley Way, Berkeley, CA 94720-1650, USA
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17
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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; 11:72415. [PMID: 35072625 PMCID: PMC8871351 DOI: 10.7554/elife.72415] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [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 tradeoff 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)
| | - Nirag Kadakia
- Department of Molecular, Cellular and Developmental Biology, Yale University
| | - Thierry Emonet
- Department of Molecular, Cellular and Developmental Biology, Yale University
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18
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Zjacic N, Scholz M. The role of food odor in invertebrate foraging. GENES, BRAIN, AND BEHAVIOR 2022; 21:e12793. [PMID: 34978135 PMCID: PMC9744530 DOI: 10.1111/gbb.12793] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 12/01/2021] [Accepted: 12/18/2021] [Indexed: 11/30/2022]
Abstract
Foraging for food is an integral part of animal survival. In small insects and invertebrates, multisensory information and optimized locomotion strategies are used to effectively forage in patchy and complex environments. Here, the importance of olfactory cues for effective invertebrate foraging is discussed in detail. We review how odors are used by foragers to move toward a likely food source and the recent models that describe this sensory-driven behavior. We argue that smell serves a second function by priming an organism for the efficient exploitation of food. By appraising food odors, invertebrates can establish preferences and better adapt to their ecological niches, thereby promoting survival. The smell of food pre-prepares the gastrointestinal system and primes feeding motor programs for more effective ingestion as well. Optimizing resource utilization affects longevity and reproduction as a result, leading to drastic changes in survival. We propose that models of foraging behavior should include odor priming, and illustrate this with a simple toy model based on the marginal value theorem. Lastly, we discuss the novel techniques and assays in invertebrate research that could investigate the interactions between odor sensing and food intake. Overall, the sense of smell is indispensable for efficient foraging and influences not only locomotion, but also organismal physiology, which should be reflected in behavioral modeling.
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Affiliation(s)
- Nicolina Zjacic
- Max Planck Research Group Neural Information FlowCenter of Advanced European Studies and Research (Caesar)BonnGermany
| | - Monika Scholz
- Max Planck Research Group Neural Information FlowCenter of Advanced European Studies and Research (Caesar)BonnGermany
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19
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Franco LM, Yaksi E. Experience-dependent plasticity modulates ongoing activity in the antennal lobe and enhances odor representations. Cell Rep 2021; 37:110165. [PMID: 34965425 PMCID: PMC8739562 DOI: 10.1016/j.celrep.2021.110165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 09/10/2021] [Accepted: 12/01/2021] [Indexed: 11/28/2022] Open
Abstract
Ongoing neural activity has been observed across several brain regions and is thought to reflect the internal state of the brain. Yet, it is important to understand how ongoing neural activity interacts with sensory experience and shapes sensory representations. Here, we show that the projection neurons of the fruit fly antennal lobe exhibit spatiotemporally organized ongoing activity. After repeated exposure to odors, we observe a gradual and cumulative decrease in the amplitude and number of calcium events occurring in the absence of odor stimulation, as well as a reorganization of correlations between olfactory glomeruli. Accompanying these plastic changes, we find that repeated odor experience decreases trial-to-trial variability and enhances the specificity of odor representations. Our results reveal an odor-experience-dependent modulation of ongoing and sensory-evoked activity at peripheral levels of the fruit fly olfactory system. The fruit fly antennal lobe exhibits spatiotemporally organized ongoing activity Repeated odor experience decreases the amplitude and number of ongoing calcium events Odor experience enhances the robustness and the specificity of odor representations Representations of different odors become more dissimilar upon repeated exposure
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Affiliation(s)
- Luis M Franco
- Neuroelectronics Research Flanders (NERF), KU Leuven, Leuven 3001, Belgium; VIB Center for the Biology of Disease, KU Leuven, Leuven 3000, Belgium; Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA.
| | - Emre Yaksi
- Neuroelectronics Research Flanders (NERF), KU Leuven, Leuven 3001, Belgium; Kavli Institute for Systems Neuroscience and Centre for Neural Computation, NTNU, Trondheim 7030, Norway.
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20
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Raithel CU, Gottfried JA. Using your nose to find your way: Ethological comparisons between human and non-human species. Neurosci Biobehav Rev 2021; 128:766-779. [PMID: 34214515 PMCID: PMC8359807 DOI: 10.1016/j.neubiorev.2021.06.040] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 06/10/2021] [Accepted: 06/25/2021] [Indexed: 02/08/2023]
Abstract
Olfaction is arguably the least valued among our sensory systems, and its significance for human behavior is often neglected. Spatial navigation represents no exception to the rule: humans are often characterized as purely visual navigators, a view that undermines the contribution of olfactory cues. Accordingly, research investigating whether and how humans use olfaction to navigate space is rare. In comparison, research on olfactory navigation in non-human species is abundant, and identifies behavioral strategies along with neural mechanisms characterizing the use of olfactory cues during spatial tasks. Using an ethological approach, our review draws from studies on olfactory navigation across species to describe the adaptation of strategies under the influence of selective pressure. Mammals interact with spatial environments by abstracting multisensory information into cognitive maps. We thus argue that olfactory cues, alongside inputs from other sensory modalities, play a crucial role in spatial navigation for mammalian species, including humans; that is, odors constitute one of the many building blocks in the formation of cognitive maps.
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Affiliation(s)
- Clara U Raithel
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, 3400 Hamilton Walk, Stemmler Hall, Room G10, Philadelphia, PA, 19104, USA; Department of Psychology, School of Arts and Sciences, University of Pennsylvania, 425 S. University Avenue, Stephen A. Levin Building, Philadelphia, PA, 19104, USA.
| | - Jay A Gottfried
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, 3400 Hamilton Walk, Stemmler Hall, Room G10, Philadelphia, PA, 19104, USA; Department of Psychology, School of Arts and Sciences, University of Pennsylvania, 425 S. University Avenue, Stephen A. Levin Building, Philadelphia, PA, 19104, USA
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21
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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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22
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Abstract
The olfactory system translates chemical signals into neuronal signals that inform behavioral decisions of the animal. Odors are cues for source identity, but if monitored long enough, they can also be used to localize the source. Odor representations should therefore be robust to changing conditions and flexible in order to drive an appropriate behavior. In this review, we aim at discussing the main computations that allow robust and flexible encoding of odor information in the olfactory neural pathway.
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23
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Marin AC, Schaefer AT, Ackels T. Spatial information from the odour environment in mammalian olfaction. Cell Tissue Res 2021; 383:473-483. [PMID: 33515294 PMCID: PMC7872987 DOI: 10.1007/s00441-020-03395-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 12/10/2020] [Indexed: 11/24/2022]
Abstract
The sense of smell is an essential modality for many species, in particular nocturnal and crepuscular mammals, to gather information about their environment. Olfactory cues provide information over a large range of distances, allowing behaviours ranging from simple detection and recognition of objects, to tracking trails and navigating using odour plumes from afar. In this review, we discuss the features of the natural olfactory environment and provide a brief overview of how odour information can be sampled and might be represented and processed by the mammalian olfactory system. Finally, we discuss recent behavioural approaches that address how mammals extract spatial information from the environment in three different contexts: odour trail tracking, odour plume tracking and, more general, olfactory-guided navigation. Recent technological developments have seen the spatiotemporal aspect of mammalian olfaction gain significant attention, and we discuss both the promising aspects of rapidly developing paradigms and stimulus control technologies as well as their limitations. We conclude that, while still in its beginnings, research on the odour environment offers an entry point into understanding the mechanisms how mammals extract information about space.
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Affiliation(s)
- Alina Cristina Marin
- Sensory Circuits and Neurotechnology Laboratory, The Francis Crick Institute, London, UK
- Department of Neuroscience, Physiology & Pharmacology, University College London, London, UK
| | - Andreas T Schaefer
- Sensory Circuits and Neurotechnology Laboratory, The Francis Crick Institute, London, UK.
- Department of Neuroscience, Physiology & Pharmacology, University College London, London, UK.
| | - Tobias Ackels
- Sensory Circuits and Neurotechnology Laboratory, The Francis Crick Institute, London, UK.
- Department of Neuroscience, Physiology & Pharmacology, University College London, London, UK.
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24
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Rapp H, Nawrot MP. A spiking neural program for sensorimotor control during foraging in flying insects. Proc Natl Acad Sci U S A 2020; 117:28412-28421. [PMID: 33122439 PMCID: PMC7668073 DOI: 10.1073/pnas.2009821117] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Foraging is a vital behavioral task for living organisms. Behavioral strategies and abstract mathematical models thereof have been described in detail for various species. To explore the link between underlying neural circuits and computational principles, we present how a biologically detailed neural circuit model of the insect mushroom body implements sensory processing, learning, and motor control. We focus on cast and surge strategies employed by flying insects when foraging within turbulent odor plumes. Using a spike-based plasticity rule, the model rapidly learns to associate individual olfactory sensory cues paired with food in a classical conditioning paradigm. We show that, without retraining, the system dynamically recalls memories to detect relevant cues in complex sensory scenes. Accumulation of this sensory evidence on short time scales generates cast-and-surge motor commands. Our generic systems approach predicts that population sparseness facilitates learning, while temporal sparseness is required for dynamic memory recall and precise behavioral control. Our work successfully combines biological computational principles with spike-based machine learning. It shows how knowledge transfer from static to arbitrary complex dynamic conditions can be achieved by foraging insects and may serve as inspiration for agent-based machine learning.
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Affiliation(s)
- Hannes Rapp
- Computational Systems Neuroscience, Institute of Zoology, University of Cologne, Cologne 50674, Germany
| | - Martin Paul Nawrot
- Computational Systems Neuroscience, Institute of Zoology, University of Cologne, Cologne 50674, Germany
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25
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Demir M, Kadakia N, Anderson HD, Clark DA, Emonet T. Walking Drosophila navigate complex plumes using stochastic decisions biased by the timing of odor encounters. eLife 2020; 9:e57524. [PMID: 33140723 PMCID: PMC7609052 DOI: 10.7554/elife.57524] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 09/15/2020] [Indexed: 11/16/2022] Open
Abstract
How insects navigate complex odor plumes, where the location and timing of odor packets are uncertain, remains unclear. Here we imaged complex odor plumes simultaneously with freely-walking flies, quantifying how behavior is shaped by encounters with individual odor packets. We found that navigation was stochastic and did not rely on the continuous modulation of speed or orientation. Instead, flies turned stochastically with stereotyped saccades, whose direction was biased upwind by the timing of prior odor encounters, while the magnitude and rate of saccades remained constant. Further, flies used the timing of odor encounters to modulate the transition rates between walks and stops. In more regular environments, flies continuously modulate speed and orientation, even though encounters can still occur randomly due to animal motion. We find that in less predictable environments, where encounters are random in both space and time, walking flies navigate with random walks biased by encounter timing.
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Affiliation(s)
- Mahmut Demir
- Department of Molecular, Cellular and Developmental Biology, Yale UniversityNew HavenUnited States
| | - Nirag Kadakia
- Department of Molecular, Cellular and Developmental Biology, Yale UniversityNew HavenUnited States
- Swartz Foundation Fellow, Yale UniversityNew HavenUnited States
| | - Hope D Anderson
- Department of Molecular, Cellular and Developmental Biology, Yale UniversityNew HavenUnited States
| | - Damon A Clark
- Department of Molecular, Cellular and Developmental Biology, Yale UniversityNew HavenUnited States
- Interdepartmental Neuroscience Program, Yale UniversityNew HavenUnited States
- Department of Physics, Yale UniversityNew HavenUnited States
| | - Thierry Emonet
- Department of Molecular, Cellular and Developmental Biology, Yale UniversityNew HavenUnited States
- Interdepartmental Neuroscience Program, Yale UniversityNew HavenUnited States
- Department of Physics, Yale UniversityNew HavenUnited States
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26
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Abstract
Human navigation relies on inputs to our paired eyes and ears. Although we also have two nasal passages, there has been little empirical indication that internostril differences yield directionality in human olfaction without involving the trigeminal system. By using optic flow that captures the pattern of apparent motion of surface elements in a visual scene, we demonstrate through formal psychophysical testing that a moderate binaral concentration disparity of a nontrigeminal odorant consistently biases recipients' perceived direction of self-motion toward the higher-concentration side, despite that they cannot verbalize which nostril smells a stronger odor. We further show that the effect depends on the internostril ratio of odor concentrations and not the numeric difference in concentration between the two nostrils. Taken together, our findings provide behavioral evidence that humans smell in stereo and subconsciously utilize stereo olfactory cues in spatial navigation.
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27
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Young BD, Escalon JA, Mathew D. Odors: from chemical structures to gaseous plumes. Neurosci Biobehav Rev 2020; 111:19-29. [PMID: 31931034 DOI: 10.1016/j.neubiorev.2020.01.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 01/07/2020] [Accepted: 01/07/2020] [Indexed: 10/25/2022]
Abstract
We are immersed within an odorous sea of chemical currents that we parse into individual odors with complex structures. Odors have been posited as determined by the structural relation between the molecules that compose the chemical compounds and their interactions with the receptor site. But, naturally occurring smells are parsed from gaseous odor plumes. To give a comprehensive account of the nature of odors the chemosciences must account for these large distributed entities as well. We offer a focused review of what is known about the perception of odor plumes for olfactory navigation and tracking, which we then connect to what is known about the role odorants play as properties of the plume in determining odor identity with respect to odor quality. We end by motivating our central claim that more research needs to be conducted on the role that odorants play within the odor plume in determining odor identity.
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Affiliation(s)
- Benjamin D Young
- Philosophy and Neuroscience, University of Nevada, 1664 N Virginia St, Reno, NV 89557, United States.
| | | | - Dennis Mathew
- Biology and Neuroscience, University of Nevada, Reno, United States.
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28
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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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29
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Olfactory Navigation and the Receptor Nonlinearity. J Neurosci 2019; 39:3713-3727. [PMID: 30846614 DOI: 10.1523/jneurosci.2512-18.2019] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 01/29/2019] [Accepted: 02/23/2019] [Indexed: 11/21/2022] Open
Abstract
The demands on a sensory system depend not only on the statistics of its inputs but also on the task. In olfactory navigation, for example, the task is to find the plume source; allocation of sensory resources may therefore be driven by aspects of the plume that are informative about source location, rather than concentration per se. Here we explore the implications of this idea for encoding odor concentration. To formalize the notion that sensory resources are limited, we considered coding strategies that partitioned the odor concentration range into a set of discriminable intervals. We developed a dynamic programming algorithm that, given the distribution of odor concentrations at several locations, determines the partitioning that conveys the most information about location. We applied this analysis to planar laser-induced fluorescence measurements of spatiotemporal odor fields with realistic advection speeds (5-20 cm/s), with or without a nearby boundary or obstacle. Across all environments, the optimal coding strategy allocated more resources (i.e., more and finer discriminable intervals) to the upper end of the concentration range than would be expected from histogram equalization, the optimal strategy if the goal were to reconstruct the plume, rather than to navigate. Finally, we show that ligand binding, as captured by the Hill equation, transforms odorant concentration into response levels in a way that approximates information maximization for navigation. This behavior occurs when the Hill dissociation constant is near the mean odor concentration, an adaptive set-point that has been observed in the olfactory system of flies.SIGNIFICANCE STATEMENT The first step of olfactory processing is receptor binding, and the resulting relationship between odorant concentration and the bound receptor fraction is a saturating one. While this Hill nonlinearity can be viewed as a distortion that is imposed by the biophysics of receptor binding, here we show that it also plays an important information-processing role in olfactory navigation. Specifically, by combining a novel dynamic-programming algorithm with physical measurements of turbulent plumes, we determine the optimal strategy for encoding odor concentration when the goal is to determine location. This strategy is distinct from histogram equalization, the strategy that maximizes information about plume concentration, and is closely approximated by the Hill nonlinearity when the binding constant is near the ambient mean.
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Jacobs LF. The navigational nose: a new hypothesis for the function of the human external pyramid. ACTA ACUST UNITED AC 2019; 222:222/Suppl_1/jeb186924. [PMID: 30728230 DOI: 10.1242/jeb.186924] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
One of the outstanding questions in evolution is why Homo erectus became the first primate species to evolve the external pyramid, i.e. an external nose. The accepted hypothesis for this trait has been its role in respiration, to warm and humidify air as it is inspired. However, new studies testing the key assumptions of the conditioning hypothesis, such as the importance of turbulence to enhance heat and moisture exchange, have called this hypothesis into question. The human nose has two functions, however, respiration and olfaction. It is thus also possible that the external nose evolved in response to selection for olfaction. The genus Homo had many adaptations for long-distance locomotion, which allowed Homo erectus to greatly expand its species range, from Africa to Asia. Long-distance navigation in birds and other species is often accomplished by orientation to environmental odors. Such olfactory navigation, in turn, is enhanced by stereo olfaction, made possible by the separation of the olfactory sensors. By these principles, the human external nose could have evolved to separate olfactory inputs to enhance stereo olfaction. This could also explain why nose shape later became so variable: as humans became more sedentary in the Neolithic, a decreasing need for long-distance movements could have been replaced by selection for other olfactory functions, such as detecting disease, that would have been critical to survival in newly dense human settlements.
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Affiliation(s)
- Lucia F Jacobs
- Department of Psychology and Helen Wills Neuroscience Institute, University of California, 2121 Berkeley Way, Berkeley, CA 94720-1650, USA
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31
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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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Baker KL, Dickinson M, Findley TM, Gire DH, Louis M, Suver MP, Verhagen JV, Nagel KI, Smear MC. Algorithms for Olfactory Search across Species. J Neurosci 2018; 38:9383-9389. [PMID: 30381430 PMCID: PMC6209839 DOI: 10.1523/jneurosci.1668-18.2018] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 09/15/2018] [Accepted: 09/18/2018] [Indexed: 11/21/2022] Open
Abstract
Localizing the sources of stimuli is essential. Most organisms cannot eat, mate, or escape without knowing where the relevant stimuli originate. For many, if not most, animals, olfaction plays an essential role in search. While microorganismal chemotaxis is relatively well understood, in larger animals the algorithms and mechanisms of olfactory search remain mysterious. In this symposium, we will present recent advances in our understanding of olfactory search in flies and rodents. Despite their different sizes and behaviors, both species must solve similar problems, including meeting the challenges of turbulent airflow, sampling the environment to optimize olfactory information, and incorporating odor information into broader navigational systems.
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Affiliation(s)
- Keeley L Baker
- Department of Neuroscience, Yale School of Medicine, New Haven 06519, Connecticut
- John B. Pierce Laboratory, New Haven 06519, Connecticut
| | - Michael Dickinson
- Division of Biology and Bioengineering, California Institute of Technology, Pasadena 91125, California
| | - Teresa M Findley
- Institute of Neuroscience, University of Oregon, Eugene 97403, Oregon
- Department of Biology, University of Oregon, Eugene 97403, Oregon
| | - David H Gire
- Department of Psychology, University of Washington, Seattle 98195, Washington
| | - Matthieu Louis
- Neuroscience Research Institute, University of Santa Barbara, Santa Barbara 93106, California
- Department of Molecular, Cellular, and Developmental Biology, University of Santa Barbara, Santa Barbara 93106, California
- Department of Physics, University of Santa Barbara, Santa Barbara 93106, California
| | - Marie P Suver
- Neuroscience Institute, New York University Langone Medical Center, New York 10016, New York, and
| | - Justus V Verhagen
- Department of Neuroscience, Yale School of Medicine, New Haven 06519, Connecticut
- John B. Pierce Laboratory, New Haven 06519, Connecticut
| | - Katherine I Nagel
- Neuroscience Institute, New York University Langone Medical Center, New York 10016, New York, and
| | - Matthew C Smear
- Institute of Neuroscience, University of Oregon, Eugene 97403, Oregon,
- Department of Psychology, University of Oregon, Eugene 97403, Oregon
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Álvarez-Salvado E, Licata AM, Connor EG, McHugh MK, King BMN, Stavropoulos N, Victor JD, Crimaldi JP, Nagel KI. Elementary sensory-motor transformations underlying olfactory navigation in walking fruit-flies. eLife 2018; 7:e37815. [PMID: 30129438 PMCID: PMC6103744 DOI: 10.7554/elife.37815] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 07/16/2018] [Indexed: 12/25/2022] Open
Abstract
Odor attraction in walking Drosophila melanogaster is commonly used to relate neural function to behavior, but the algorithms underlying attraction are unclear. Here, we develop a high-throughput assay to measure olfactory behavior in response to well-controlled sensory stimuli. We show that odor evokes two behaviors: an upwind run during odor (ON response), and a local search at odor offset (OFF response). Wind orientation requires antennal mechanoreceptors, but search is driven solely by odor. Using dynamic odor stimuli, we measure the dependence of these two behaviors on odor intensity and history. Based on these data, we develop a navigation model that recapitulates the behavior of flies in our apparatus, and generates realistic trajectories when run in a turbulent boundary layer plume. The ability to parse olfactory navigation into quantifiable elementary sensori-motor transformations provides a foundation for dissecting neural circuits that govern olfactory behavior.
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Affiliation(s)
- Efrén Álvarez-Salvado
- Neuroscience InstituteNew York University Langone Medical CenterNew YorkUnited States
| | - Angela M Licata
- Neuroscience InstituteNew York University Langone Medical CenterNew YorkUnited States
| | - Erin G Connor
- Department of Civil, Environmental and Architectural EngineeringUniversity of Colorado BoulderBoulderUnited States
| | - Margaret K McHugh
- Department of Civil, Environmental and Architectural EngineeringUniversity of Colorado BoulderBoulderUnited States
| | - Benjamin MN King
- Neuroscience InstituteNew York University Langone Medical CenterNew YorkUnited States
| | - Nicholas Stavropoulos
- Neuroscience InstituteNew York University Langone Medical CenterNew YorkUnited States
| | - Jonathan D Victor
- Institute for Computational BiomedicineWeill Cornell Medical CollegeNew YorkUnited States
- Feil Family Brain and Mind Research InstituteWeill Cornell Medical CollegeNew YorkUnited States
| | - John P Crimaldi
- Department of Civil, Environmental and Architectural EngineeringUniversity of Colorado BoulderBoulderUnited States
| | - Katherine I Nagel
- Neuroscience InstituteNew York University Langone Medical CenterNew YorkUnited States
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