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Si G, Kanwal JK, Hu Y, Tabone CJ, Baron J, Berck M, Vignoud G, Samuel ADT. Structured Odorant Response Patterns across a Complete Olfactory Receptor Neuron Population. Neuron 2019; 101:950-962.e7. [PMID: 30683545 DOI: 10.1016/j.neuron.2018.12.030] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 10/29/2018] [Accepted: 12/20/2018] [Indexed: 11/15/2022]
Abstract
Odor perception allows animals to distinguish odors, recognize the same odor across concentrations, and determine concentration changes. How the activity patterns of primary olfactory receptor neurons (ORNs), at the individual and population levels, facilitate distinguishing these functions remains poorly understood. Here, we interrogate the complete ORN population of the Drosophila larva across a broadly sampled panel of odorants at varying concentrations. We find that the activity of each ORN scales with the concentration of any odorant via a fixed dose-response function with a variable sensitivity. Sensitivities across odorants and ORNs follow a power-law distribution. Much of receptor sensitivity to odorants is accounted for by a single geometrical property of molecular structure. Similarity in the shape of temporal response filters across odorants and ORNs extend these relationships to fluctuating environments. These results uncover shared individual- and population-level patterns that together lend structure to support odor perceptions.
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Affiliation(s)
- Guangwei Si
- Department of Physics, Harvard University, Cambridge, MA 02138, USA; Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
| | - Jessleen K Kanwal
- Center for Brain Science, Harvard University, Cambridge, MA 02138, USA; Program in Neuroscience, Harvard University, Cambridge, MA 02138, USA
| | - Yu Hu
- Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
| | - Christopher J Tabone
- Department of Physics, Harvard University, Cambridge, MA 02138, USA; Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
| | - Jacob Baron
- Department of Physics, Harvard University, Cambridge, MA 02138, USA; Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
| | - Matthew Berck
- Department of Physics, Harvard University, Cambridge, MA 02138, USA; Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
| | - Gaetan Vignoud
- Department of Physics, Harvard University, Cambridge, MA 02138, USA; Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
| | - Aravinthan D T Samuel
- Department of Physics, Harvard University, Cambridge, MA 02138, USA; Center for Brain Science, Harvard University, Cambridge, MA 02138, USA.
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Abstract
The identification, in the late 20th century, of unexpectedly large families of G-protein-coupled chemosensory receptors revolutionised our understanding of the olfactory system. The discovery that non-selective olfactory sensory neurons express a single olfactory receptor type and project to a specific glomerulus in the main olfactory bulb provided fundamental insight into the spatial pattern of odour representation in the main olfactory bulb. Studies using head-fixed awake mice and optogenetics have revealed the importance of the timing of glomerular input in relation to the sniff cycle and the role of piriform cortex in odour object recognition. What in the 1970s had appeared to be a relatively simple dichotomy between odour detection by the main olfactory system and pheromone detection by the vomeronasal system has been found to consist of multiple subsystems. These mediate innate responses to odours and pheromones and to substances as diverse as O2, volatile urinary constituents, peptides and proteins.
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Affiliation(s)
- Peter A Brennan
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
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53
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Wanner AA, Vishwanathan A. Methods for Mapping Neuronal Activity to Synaptic Connectivity: Lessons From Larval Zebrafish. Front Neural Circuits 2018; 12:89. [PMID: 30410437 PMCID: PMC6209671 DOI: 10.3389/fncir.2018.00089] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 09/28/2018] [Indexed: 12/29/2022] Open
Abstract
For a mechanistic understanding of neuronal circuits in the brain, a detailed description of information flow is necessary. Thereby it is crucial to link neuron function to the underlying circuit structure. Multiphoton calcium imaging is the standard technique to record the activity of hundreds of neurons simultaneously. Similarly, recent advances in high-throughput electron microscopy techniques allow for the reconstruction of synaptic resolution wiring diagrams. These two methods can be combined to study both function and structure in the same specimen. Due to its small size and optical transparency, the larval zebrafish brain is one of the very few vertebrate systems where both, activity and connectivity of all neurons from entire, anatomically defined brain regions, can be analyzed. Here, we describe different methods and the tools required for combining multiphoton microscopy with dense circuit reconstruction from electron microscopy stacks of entire brain regions in the larval zebrafish.
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Affiliation(s)
- Adrian A Wanner
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ, United States
| | - Ashwin Vishwanathan
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ, United States
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Rupprecht P, Friedrich RW. Precise Synaptic Balance in the Zebrafish Homolog of Olfactory Cortex. Neuron 2018; 100:669-683.e5. [PMID: 30318416 DOI: 10.1016/j.neuron.2018.09.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 07/04/2018] [Accepted: 09/06/2018] [Indexed: 01/04/2023]
Abstract
Neuronal computations critically depend on the connectivity rules that govern the convergence of excitatory and inhibitory synaptic signals onto individual neurons. To examine the functional synaptic organization of a distributed memory network, we performed voltage clamp recordings in telencephalic area Dp of adult zebrafish, the homolog of olfactory cortex. In neurons of posterior Dp, odor stimulation evoked large, recurrent excitatory and inhibitory inputs that established a transient state of high conductance and synaptic balance. Excitation and inhibition in individual neurons were co-tuned to different odors and correlated on slow and fast timescales. This precise synaptic balance implies specific connectivity among Dp neurons, despite the absence of an obvious topography. Precise synaptic balance stabilizes activity patterns in different directions of coding space and in time while preserving high bandwidth. The coordinated connectivity of excitatory and inhibitory subnetworks in Dp therefore supports fast recurrent memory operations.
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Affiliation(s)
- Peter Rupprecht
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland; Faculty of Natural Sciences, University of Basel, 4003 Basel, Switzerland.
| | - Rainer W Friedrich
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland; Faculty of Natural Sciences, University of Basel, 4003 Basel, Switzerland.
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55
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Zebrafish: an emerging real-time model system to study Alzheimer's disease and neurospecific drug discovery. Cell Death Discov 2018; 4:45. [PMID: 30302279 PMCID: PMC6170431 DOI: 10.1038/s41420-018-0109-7] [Citation(s) in RCA: 89] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 08/21/2018] [Accepted: 08/23/2018] [Indexed: 12/22/2022] Open
Abstract
Zebrafish (Danio rerio) is emerging as an increasingly successful model for translational research on human neurological disorders. In this review, we appraise the high degree of neurological and behavioural resemblance of zebrafish with humans. It is highly validated as a powerful vertebrate model for investigating human neurodegenerative diseases. The neuroanatomic and neurochemical pathways of zebrafish brain exhibit a profound resemblance with the human brain. Physiological, emotional and social behavioural pattern similarities between them have also been well established. Interestingly, zebrafish models have been used successfully to simulate the pathology of Alzheimer’s disease (AD) as well as Tauopathy. Their relatively simple nervous system and the optical transparency of the embryos permit real-time neurological imaging. Here, we further elaborate on the use of recent real-time imaging techniques to obtain vital insights into the neurodegeneration that occurs in AD. Zebrafish is adeptly suitable for Ca2+ imaging, which provides a better understanding of neuronal activity and axonal dystrophy in a non-invasive manner. Three-dimensional imaging in zebrafish is a rapidly evolving technique, which allows the visualisation of the whole organism for an elaborate in vivo functional and neurophysiological analysis in disease condition. Suitability to high-throughput screening and similarity with humans makes zebrafish an excellent model for screening neurospecific compounds. Thus, the zebrafish model can be pivotal in bridging the gap from the bench to the bedside. This fish is becoming an increasingly successful model to understand AD with further scope for investigation in neurodevelopment and neurodegeneration, which promises exciting research opportunities in the future.
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Shamchuk AL, Blunt BJ, Lyons DD, Wang MQ, Gasheva A, Lewis CR, Tomlin K, Hazard ES, Hardiman G, Tierney KB. Nucleobase-containing compounds evoke behavioural, olfactory, and transcriptional responses in model fishes. Facets (Ott) 2018. [DOI: 10.1139/facets-2017-0101] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The sensory system of animals detects a massive and unknown array of chemical cues that evoke a diversity of physiological and behavioural responses. One group of nitrogen-containing carbon ring chemicals—nucleobases—are thought to be involved in numerous behaviours yet have received little attention. We took a top-down approach to examine responses evoked by nucleobases at behavioural, tissue, and gene expression levels. Fish generally avoided nucleobases, and this behaviour, when observed, was driven by purines but not pyrimidines. At the tissue level, olfactory neuron generator potential responses tended to be concentration specific and robust at concentrations lower than amino acid detection ranges. In terms of gene expression, more than 2000 genes were significantly upregulated following nucleobase exposure, some of which were expected (e.g., genes involved in purine binding) and some of which were not (e.g., tubulin-related genes). Humanized RNA pathway analysis showed that we had exposed the animal to a nucleobase. Our data indicate that responses to nucleobase-containing compounds may be highly structure based and are evident from changes in behaviour to mRNA expression. Many of these responses were surprising, and all provide numerous routes for further research endeavour.
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Affiliation(s)
- Angela L. Shamchuk
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - Brian J. Blunt
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - Danielle D. Lyons
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - Mo Qi Wang
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - Anastasia Gasheva
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - Carlie R. Lewis
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - Kirsten Tomlin
- Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2, Canada
| | - E. Starr Hazard
- Center for Genomic Medicine, Medical University of South Carolina, Charleston, SC 29425, USA
- Library Science and Informatics, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Gary Hardiman
- Center for Genomic Medicine, Medical University of South Carolina, Charleston, SC 29425, USA
- Department of Medicine and Public Health Sciences, Medical University of South Carolina, Charleston, SC 29425, USA
- Laboratory for Marine Systems Biology, Hollings Marine Laboratory, Charleston, SC 29412, USA
| | - Keith B. Tierney
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
- School of Public Health, University of Alberta, Edmonton, AB T6G 1C9, Canada
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57
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Rapid olfactory discrimination learning in adult zebrafish. Exp Brain Res 2018; 236:2959-2969. [PMID: 30088022 PMCID: PMC6223846 DOI: 10.1007/s00221-018-5352-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 08/02/2018] [Indexed: 01/24/2023]
Abstract
The zebrafish is a model organism to study olfactory information processing, but efficient behavioral procedures to analyze olfactory discrimination and memory are lacking. We devised an automated odor discrimination task for adult zebrafish based on olfactory conditioning of feeding behavior. Presentation of a conditioned odor (CS+), but not a neutral odor (CS−) was followed by food delivery at a specific location. Fish developed differential behavioral responses to CS+ and CS− within a few trials. The behavioral response to the CS+ was complex and included components reminiscent of food search such as increased swimming speed and water surface sampling. Appetitive behavior was therefore quantified by a composite score that combined measurements of multiple behavioral parameters. Robust discrimination behavior was observed in different strains, even when odors were chemically similar, and learned preferences could overcome innate odor preferences. These results confirm that zebrafish can rapidly learn to make fine odor discriminations. The procedure is efficient and provides novel opportunities to dissect the neural mechanisms underlying olfactory discrimination and memory.
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58
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Blin M, Tine E, Meister L, Elipot Y, Bibliowicz J, Espinasa L, Rétaux S. Developmental evolution and developmental plasticity of the olfactory epithelium and olfactory skills in Mexican cavefish. Dev Biol 2018; 441:242-251. [PMID: 29709597 DOI: 10.1016/j.ydbio.2018.04.019] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 04/19/2018] [Accepted: 04/24/2018] [Indexed: 11/16/2022]
Abstract
The fish Astyanax mexicanus comes in two forms: the normal surface-dwelling (SF) and the blind depigmented cave-adapted (CF) morphs. Among many phenotypic differences, cavefish show enhanced olfactory sensitivity to detect amino-acid odors and they possess large olfactory sensory organs. Here, we questioned the relationship between the size of the olfactory organ and olfactory capacities. Comparing olfactory detection abilities of CF, SF and F1 hybrids with various olfactory epithelium (OE) sizes in behavioral tests, we concluded that OE size is not the only factor involved. Other possibilities were envisaged. First, olfactory behavior was tested in SF raised in the dark or after embryonic lens ablation, which leads to eye degeneration and mimics the CF condition. Both absence of visual function and absence of visual organs improved the SF olfactory detection capacities, without affecting the size of their OE. This suggested that developmental plasticity occurs between the visual and the olfactory modalities, and can be recruited in SF after visual deprivation. Second, the development of the olfactory epithelium was compared in SF and CF in their first month of life. Proliferation, cell death, neuronal lifespan, and olfactory progenitor cell cycling properties were identical in the two morphs. By contrast, the proportions of the three main olfactory sensory neurons subtypes (ciliated, microvillous and crypt) in their OE differed. OMP-positive ciliated neurons were more represented in SF, TRPC2-positive microvillous neurons were proportionately more abundant in CF, and S100-positive crypt cells were found in equal densities in the two morphs. Thus, general proliferative properties of olfactory progenitors are identical but neurogenic properties differ and lead to variations in the neuronal composition of the OE in SF and CF. Together, these experiments suggest that there are at least two components in the evolution of cavefish olfactory skills: (1) one part of eye-dependent developmental phenotypic plasticity, which does not depend on the size of the olfactory organ, and (2) one part of developmental evolution of the OE, which may stem from embryonic specification of olfactory neurons progenitor pools.
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Affiliation(s)
- Maryline Blin
- Paris-Saclay Institute of Neuroscience, Université Paris-Sud, CNRS UMR9197, Université Paris-Saclay, Avenue de la terrasse, 91198 Gif-sur-Yvette, France
| | - Eugène Tine
- Paris-Saclay Institute of Neuroscience, Université Paris-Sud, CNRS UMR9197, Université Paris-Saclay, Avenue de la terrasse, 91198 Gif-sur-Yvette, France
| | - Lydvina Meister
- Paris-Saclay Institute of Neuroscience, Université Paris-Sud, CNRS UMR9197, Université Paris-Saclay, Avenue de la terrasse, 91198 Gif-sur-Yvette, France
| | - Yannick Elipot
- Paris-Saclay Institute of Neuroscience, Université Paris-Sud, CNRS UMR9197, Université Paris-Saclay, Avenue de la terrasse, 91198 Gif-sur-Yvette, France
| | - Jonathan Bibliowicz
- Paris-Saclay Institute of Neuroscience, Université Paris-Sud, CNRS UMR9197, Université Paris-Saclay, Avenue de la terrasse, 91198 Gif-sur-Yvette, France
| | - Luis Espinasa
- Paris-Saclay Institute of Neuroscience, Université Paris-Sud, CNRS UMR9197, Université Paris-Saclay, Avenue de la terrasse, 91198 Gif-sur-Yvette, France
| | - Sylvie Rétaux
- Paris-Saclay Institute of Neuroscience, Université Paris-Sud, CNRS UMR9197, Université Paris-Saclay, Avenue de la terrasse, 91198 Gif-sur-Yvette, France.
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59
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Integrative whole-brain neuroscience in larval zebrafish. Curr Opin Neurobiol 2018; 50:136-145. [PMID: 29486425 DOI: 10.1016/j.conb.2018.02.004] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 01/23/2018] [Accepted: 02/04/2018] [Indexed: 11/22/2022]
Abstract
Due to their small size and transparency, zebrafish larvae are amenable to a range of fluorescence microscopy techniques. With the development of sensitive genetically encoded calcium indicators, this has extended to the whole-brain imaging of neural activity with cellular resolution. This technique has been used to study brain-wide population dynamics accompanying sensory processing and sensorimotor transformations, and has spurred the development of innovative closed-loop behavioral paradigms in which stimulus-response relationships can be studied. More recently, microscopes have been developed that allow whole-brain calcium imaging in freely swimming and behaving larvae. In this review, we highlight the technologies underlying whole-brain functional imaging in zebrafish, provide examples of the sensory and motor processes that have been studied with this technique, and discuss the need to merge data from whole-brain functional imaging studies with neurochemical and anatomical information to develop holistic models of functional neural circuits.
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60
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Carcaud J, Giurfa M, Sandoz JC. Differential Processing by Two Olfactory Subsystems in the Honeybee Brain. Neuroscience 2018; 374:33-48. [PMID: 29374539 DOI: 10.1016/j.neuroscience.2018.01.029] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 01/08/2018] [Accepted: 01/12/2018] [Indexed: 10/18/2022]
Abstract
Among insects, Hymenoptera present a striking olfactory system with a clear neural dichotomy from the periphery to higher order centers, based on two main tracts of second-order (projection) neurons: the medial and lateral antennal lobe tracts (m-ALT and l-ALT). Despite substantial work on this dual pathway, its exact function is yet unclear. Here, we ask how attributes of odor quality and odor quantity are represented in the projection neurons (PNs) of the two pathways. Using in vivo calcium imaging, we compared the responses of m-ALT and l-ALT PNs of the honey bee Apis mellifera to a panel of 16 aliphatic odorants, and to three chosen odorants at eight concentrations. The results show that each pathway conveys differential information about odorants' chemical features or concentration to higher order centers. While the l-ALT primarily conveys information about odorants' chain length, the m-ALT informs about odorants' functional group. Furthermore, each tract can only predict chemical distances or bees' behavioral responses for odorants that differ according to its main feature, chain length or functional group. Generally l-ALT neurons displayed more graded dose-response relationships than m-ALT neurons, with a correspondingly smoother progression of inter-odor distances with increasing concentration. Comparison of these results with previous data recorded at AL input reveals differential processing by local networks within the two pathways. These results support the existence of parallel processing of odorant features in the insect brain.
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Affiliation(s)
- Julie Carcaud
- Evolution, Genomes, Behavior and Ecology, CNRS, Univ Paris-Sud, IRD, Université Paris Saclay, 1 avenue de la Terrasse, 91198 Gif-sur-Yvette, France; Centre de Recherches sur la Cognition Animale, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 31062 Toulouse Cedex 9, France
| | - Martin Giurfa
- Centre de Recherches sur la Cognition Animale, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 31062 Toulouse Cedex 9, France
| | - Jean-Christophe Sandoz
- Evolution, Genomes, Behavior and Ecology, CNRS, Univ Paris-Sud, IRD, Université Paris Saclay, 1 avenue de la Terrasse, 91198 Gif-sur-Yvette, France.
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61
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Kotrschal A, Zeng HL, van der Bijl W, Öhman-Mägi C, Kotrschal K, Pelckmans K, Kolm N. Evolution of brain region volumes during artificial selection for relative brain size. Evolution 2017; 71:2942-2951. [PMID: 28986929 DOI: 10.1111/evo.13373] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 09/14/2017] [Accepted: 09/24/2017] [Indexed: 12/28/2022]
Abstract
The vertebrate brain shows an extremely conserved layout across taxa. Still, the relative sizes of separate brain regions vary markedly between species. One interesting pattern is that larger brains seem associated with increased relative sizes only of certain brain regions, for instance telencephalon and cerebellum. Till now, the evolutionary association between separate brain regions and overall brain size is based on comparative evidence and remains experimentally untested. Here, we test the evolutionary response of brain regions to directional selection on brain size in guppies (Poecilia reticulata) selected for large and small relative brain size. In these animals, artificial selection led to a fast response in relative brain size, while body size remained unchanged. We use microcomputer tomography to investigate how the volumes of 11 main brain regions respond to selection for larger versus smaller brains. We found no differences in relative brain region volumes between large- and small-brained animals and only minor sex-specific variation. Also, selection did not change allometric scaling between brain and brain region sizes. Our results suggest that brain regions respond similarly to strong directional selection on relative brain size, which indicates that brain anatomy variation in contemporary species most likely stem from direct selection on key regions.
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Affiliation(s)
| | - Hong-Li Zeng
- Department of Mathematics, Uppsala University, Uppsala, Sweden
| | | | | | - Kurt Kotrschal
- Department of Behavioural Biology, University of Vienna, Vienna, Austria.,Konrad Lorenz Forschungsstelle, University of Vienna, Vienna, Austria.,Wolf Science Center, University of Veterinary Medicine Vienna, Ernstbrunn, Austria
| | | | - Niclas Kolm
- Department of Zoology, Stockholm University, Stockholm, Sweden
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62
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Odor-evoked inhibition of olfactory sensory neurons drives olfactory perception in Drosophila. Nat Commun 2017; 8:1357. [PMID: 29116083 PMCID: PMC5676773 DOI: 10.1038/s41467-017-01185-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 08/24/2017] [Indexed: 11/28/2022] Open
Abstract
Inhibitory response occurs throughout the nervous system, including the peripheral olfactory system. While odor-evoked excitation in peripheral olfactory cells is known to encode odor information, the molecular mechanism and functional roles of odor-evoked inhibition remain largely unknown. Here, we examined Drosophila olfactory sensory neurons and found that inhibitory odors triggered outward receptor currents by reducing the constitutive activities of odorant receptors, inhibiting the basal spike firing in olfactory sensory neurons. Remarkably, this odor-evoked inhibition of olfactory sensory neurons elicited by itself a full range of olfactory behaviors from attraction to avoidance, as did odor-evoked olfactory sensory neuron excitation. These results indicated that peripheral inhibition is comparable to excitation in encoding sensory signals rather than merely regulating excitation. Furthermore, we demonstrated that a bidirectional code with both odor-evoked inhibition and excitation in single olfactory sensory neurons increases the odor-coding capacity, providing a means of efficient sensory encoding. It is well established that odor-evoked excitation in olfactory sensory neurons (OSNs) encodes odor information. Here the authors report that odor-evoked inhibition in OSNs of Drosophila also encodes odor identity, and can in itself drive both attraction and avoidance behaviors.
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63
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Grabe V, Sachse S. Fundamental principles of the olfactory code. Biosystems 2017; 164:94-101. [PMID: 29054468 DOI: 10.1016/j.biosystems.2017.10.010] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 10/13/2017] [Accepted: 10/16/2017] [Indexed: 02/06/2023]
Abstract
Sensory coding represents a basic principle of all phyla in nature: species attempt to perceive their natural surroundings and to make sense of them. Ultimately, sensory coding is the only way to allow a species to make the kinds of crucial decisions that lead to a behavioral response. In this manner, animals are able to detect numerous parameters, ranging from temperature and humidity to light and sound to volatile or non-volatile chemicals. Most of these environmental cues represent a clearly defined stimulus array that can be described along a single physical parameter, such as wavelength or frequency; odorants, in contrast, cannot. The odor space encompasses an enormous and nearly infinite number of diverse stimuli that cannot be classified according to their positions along a single dimension. Hence, the olfactory system has to encode and translate the vast odor array into an accurate neural map in the brain. In this review, we will outline the relevant steps of the olfactory code and describe its progress along the olfactory pathway, i.e., from the peripheral olfactory organs to the first olfactory center in the brain and then to the higher processing areas where the odor perception takes place, enabling an organism to make odor-guided decisions. We will focus mainly on studies from the vinegar fly Drosophila melanogaster, but we will also indicate similarities to and differences from the olfactory system of other invertebrate species as well as of the vertebrate world.
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Affiliation(s)
- Veit Grabe
- Max Planck Institute for Chemical Ecology, Department of EvolutionaryNeuroethology, Hans-Knoell-Str. 8, 07745 Jena, Germany
| | - Silke Sachse
- Max Planck Institute for Chemical Ecology, Department of EvolutionaryNeuroethology, Hans-Knoell-Str. 8, 07745 Jena, Germany.
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64
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Shao X, Lakhina V, Dang P, Cheng RP, Marcaccio CL, Raper JA. Olfactory sensory axons target specific protoglomeruli in the olfactory bulb of zebrafish. Neural Dev 2017; 12:18. [PMID: 29020985 PMCID: PMC5637265 DOI: 10.1186/s13064-017-0095-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 09/24/2017] [Indexed: 01/08/2023] Open
Abstract
Background The axons of Olfactory Sensory Neurons (OSNs) project to reproducible target locations within the Olfactory Bulb (OB), converting odorant experience into a spatial map of neural activity. We characterized the initial targeting of OSN axons in the zebrafish, a model system suitable for studying axonal targeting early in development. In this system the initial targets of OSN axons are a small number of distinct, individually identifiable neuropilar regions called protoglomeruli. Previously, Olfactory Marker Protein-expressing and TRPC2-expressing classes of OSNs were shown to project to specific, non-overlapping sets of protoglomeruli, indicating that particular subsets of OSNs project to specific protoglomerular targets. We set out to map the relationship between the classical Odorant Receptor (OR) an OSN chooses to express and the protoglomerulus its axon targets. Methods A panel of BACs were recombineered so that the axons of OSNs choosing to express modified ORs were fluorescently labeled. Axon projections were followed into the olfactory bulb to determine the protoglomeruli in which they terminated. Results RNA-seq demonstrates that OSNs express a surprisingly wide variety of ORs and Trace Amine Associated Receptors (TAARs) very early when sensory axons are arriving in the bulb. Only a single OR is expressed in any given OSN even at these early developmental times. We used a BAC expression technique to map the trajectories of OSNs expressing specific odorant receptors. ORs can be divided into three clades based upon their sequence similarities. OSNs expressing ORs from two of these clades project to the CZ protoglomerulus, while OSNs expressing ORs from the third clade project to the DZ protoglomerulus. In contrast, OSNs expressing a particular TAAR project to multiple protoglomeruli. Neither OR choice nor axonal targeting are related to the position an OSN occupies within the olfactory pit. Conclusions Our results demonstrate that it is not the choice of a particular OR, but of one from a category of ORs, that is related to initial OSN target location within the olfactory bulb. These choices are not related to OSN position within the olfactory epithelium.
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Affiliation(s)
- Xin Shao
- Department of Neuroscience, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Vanisha Lakhina
- Department of Neuroscience, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA.,Department of Molecular Biology, Princeton University, Princeton, NJ, 08540, USA
| | - Puneet Dang
- Department of Neuroscience, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Ryan P Cheng
- Department of Neuroscience, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Christina L Marcaccio
- Department of Neuroscience, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Jonathan A Raper
- Department of Neuroscience, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA. .,, 105 Johnson Pavilion, 3610 Hamilton Walk, Philadelphia, PA, 19104, USA.
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Terni B, Pacciolla P, Masanas H, Gorostiza P, Llobet A. Tight temporal coupling between synaptic rewiring of olfactory glomeruli and the emergence of odor-guided behavior in Xenopus tadpoles. J Comp Neurol 2017; 525:3769-3783. [PMID: 28815589 DOI: 10.1002/cne.24303] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 08/09/2017] [Accepted: 08/10/2017] [Indexed: 12/13/2022]
Abstract
Olfactory sensory neurons (OSNs) are chemoreceptors that establish excitatory synapses within glomeruli of the olfactory bulb. OSNs undergo continuous turnover throughout life, causing the constant replacement of their synaptic contacts. Using Xenopus tadpoles as an experimental system to investigate rewiring of glomerular connectivity, we show that novel OSN synapses can transfer information immediately after formation, mediating olfactory-guided behavior. Tadpoles recover the ability to detect amino acids 4 days after bilateral olfactory nerve transection. Restoration of olfactory-guided behavior depends on the efficient reinsertion of OSNs to the olfactory bulb. Presynaptic terminals of incipient synaptic contacts generate calcium transients in response to odors, triggering long lasting depolarization of olfactory glomeruli. The functionality of reconnected terminals relies on well-defined readily releasable and cytoplasmic vesicle pools. The continuous growth of non-compartmentalized axonal processes provides a vesicle reservoir to nascent release sites, which contrasts to the gradual development of cytoplasmic vesicle pools in conventional excitatory synapses. The immediate availability of fully functional synapses upon formation supports an age-independent contribution of OSNs to the generation of odor maps.
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Affiliation(s)
- Beatrice Terni
- Laboratory of Neurobiology, Department of Pathology and Experimental Therapeutics, Faculty of Medicine, University of Barcelona, Barcelona, Spain.,Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain
| | - Paolo Pacciolla
- Laboratory of Neurobiology, Department of Pathology and Experimental Therapeutics, Faculty of Medicine, University of Barcelona, Barcelona, Spain.,Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain
| | - Helena Masanas
- Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain.,Institut de Bioenginyeria de Catalunya (IBEC), Barcelona, Spain
| | - Pau Gorostiza
- Institut de Bioenginyeria de Catalunya (IBEC), Barcelona, Spain.,Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain.,Network Biomedic Research Center in Biophysics, Bioengineering and Nanomedicine (CIBER-bbn), Madrid, Spain
| | - Artur Llobet
- Laboratory of Neurobiology, Department of Pathology and Experimental Therapeutics, Faculty of Medicine, University of Barcelona, Barcelona, Spain.,Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain.,Institute of Neurosciences, University of Barcelona, Barcelona, Spain
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66
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Hinaux H, Devos L, Blin M, Elipot Y, Bibliowicz J, Alié A, Rétaux S. Sensory evolution in blind cavefish is driven by early embryonic events during gastrulation and neurulation. Development 2017; 143:4521-4532. [PMID: 27899509 DOI: 10.1242/dev.141291] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 10/20/2016] [Indexed: 11/20/2022]
Abstract
Natural variations in sensory systems constitute adaptive responses to the environment. Here, we compared sensory placode development in the blind cave-adapted morph and the eyed river-dwelling morph of Astyanax mexicanus Focusing on the lens and olfactory placodes, we found a trade-off between these two sensory components in the two morphs: from neural plate stage onwards, cavefish have larger olfactory placodes and smaller lens placodes. In a search for developmental mechanisms underlying cavefish sensory evolution, we analyzed the roles of Shh, Fgf8 and Bmp4 signaling, which are known to be fundamental in patterning the vertebrate head and are subtly modulated in space and time during cavefish embryogenesis. Modulating these signaling systems at the end of gastrulation shifted the balance toward a larger olfactory derivative. Olfactory tests to assess potential behavioral outcomes of such developmental evolution revealed that Astyanax cavefish are able to respond to a 105-fold lower concentration of amino acids than their surface-dwelling counterparts. We suggest that similar evolutionary developmental mechanisms may be used throughout vertebrates to drive adaptive sensory specializations according to lifestyle and habitat.
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Affiliation(s)
- Hélène Hinaux
- DECA group, Paris-Saclay Institute of Neuroscience, CNRS, Université Paris Sud, Université Paris-Saclay, Avenue de la terrasse, Gif-sur-Yvette 91198, France
| | - Lucie Devos
- DECA group, Paris-Saclay Institute of Neuroscience, CNRS, Université Paris Sud, Université Paris-Saclay, Avenue de la terrasse, Gif-sur-Yvette 91198, France
| | - Maryline Blin
- DECA group, Paris-Saclay Institute of Neuroscience, CNRS, Université Paris Sud, Université Paris-Saclay, Avenue de la terrasse, Gif-sur-Yvette 91198, France
| | - Yannick Elipot
- DECA group, Paris-Saclay Institute of Neuroscience, CNRS, Université Paris Sud, Université Paris-Saclay, Avenue de la terrasse, Gif-sur-Yvette 91198, France
| | - Jonathan Bibliowicz
- DECA group, Paris-Saclay Institute of Neuroscience, CNRS, Université Paris Sud, Université Paris-Saclay, Avenue de la terrasse, Gif-sur-Yvette 91198, France
| | - Alexandre Alié
- DECA group, Paris-Saclay Institute of Neuroscience, CNRS, Université Paris Sud, Université Paris-Saclay, Avenue de la terrasse, Gif-sur-Yvette 91198, France
| | - Sylvie Rétaux
- DECA group, Paris-Saclay Institute of Neuroscience, CNRS, Université Paris Sud, Université Paris-Saclay, Avenue de la terrasse, Gif-sur-Yvette 91198, France
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67
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Wolf S, Gelis L, Dörrich S, Hatt H, Kraft P. Evidence for a shape-based recognition of odorants in vivo in the human nose from an analysis of the molecular mechanism of lily-of-the-valley odorants detection in the Lilial and Bourgeonal family using the C/Si/Ge/Sn switch strategy. PLoS One 2017; 12:e0182147. [PMID: 28763484 PMCID: PMC5538716 DOI: 10.1371/journal.pone.0182147] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 07/13/2017] [Indexed: 01/20/2023] Open
Abstract
We performed an analysis of possible mechanisms of ligand recognition in the human nose. The analysis is based on in vivo odor threshold determination and in vitro Ca2+ imaging assays with a C/Si/Ge/Sn switch strategy applied to the compounds Lilial and Bourgeonal, to differentiate between different molecular mechanisms of odorant detection. Our results suggest that odorant detection under threshold conditions is mainly based on the molecular shape, i.e. the van der Waals surface, and electrostatics of the odorants. Furthermore, we show that a single olfactory receptor type is responsible for odor detection of Bourgeonal at the threshold level in humans in vivo. Carrying out a QM analysis of vibrational energies contained in the odorants, there is no evidence for a vibration-based recognition.
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Affiliation(s)
- Steffen Wolf
- Department of Biophysics, CAS-MPG Partner Institute for Computational Biology, Key Laboratory of Computational Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, P.R. China
- Department of Biophysics, Ruhr-University Bochum, Bochum, Germany
| | - Lian Gelis
- Department of Cellphysiology, Ruhr-University Bochum, Bochum, Germany
| | - Steffen Dörrich
- Institute of Inorganic Chemistry, University of Würzburg, Würzburg, Germany
| | - Hanns Hatt
- Department of Cellphysiology, Ruhr-University Bochum, Bochum, Germany
| | - Philip Kraft
- Fragrance Research, Givaudan Schweiz AG, Dübendorf, Switzerland
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68
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Processing of Intraoral Olfactory and Gustatory Signals in the Gustatory Cortex of Awake Rats. J Neurosci 2017; 37:244-257. [PMID: 28077705 DOI: 10.1523/jneurosci.1926-16.2016] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 11/08/2016] [Accepted: 11/11/2016] [Indexed: 12/28/2022] Open
Abstract
The integration of gustatory and olfactory information is essential to the perception of flavor. Human neuroimaging experiments have pointed to the gustatory cortex (GC) as one of the areas involved in mediating flavor perception. Although GC's involvement in encoding the chemical identity and hedonic value of taste stimuli is well studied, it is unknown how single GC neurons process olfactory stimuli emanating from the mouth. In this study, we relied on multielectrode recordings to investigate how single GC neurons respond to intraorally delivered tastants and tasteless odorants dissolved in water and whether/how these two modalities converge in the same neurons. We found that GC neurons could either be unimodal, responding exclusively to taste (taste-only) or odor (odor-only), or bimodal, responding to both gustatory and olfactory stimuli. Odor responses were confirmed to result from retronasal olfaction: monitoring respiration revealed that exhalation preceded odor-evoked activity and reversible inactivation of olfactory receptors in the nasal epithelium significantly reduced responses to intraoral odorants but not to tastants. Analysis of bimodal neurons revealed that they encode palatability significantly better than the unimodal taste-only group. Bimodal neurons exhibited similar responses to palatable tastants and odorants dissolved in water. This result suggested that odorized water could be palatable. This interpretation was further supported with a brief access task, where rats avoided consuming aversive taste stimuli and consumed the palatable tastants and dissolved odorants. These results demonstrate the convergence of the chemosensory components of flavor onto single GC neurons and provide evidence for the integration of flavor with palatability coding. SIGNIFICANCE STATEMENT Food perception and choice depend upon the concurrent processing of olfactory and gustatory signals from the mouth. The primary gustatory cortex has been proposed to integrate chemosensory stimuli; however, no study has examined the single-unit responses to intraoral odorant presentation. Here we found that neurons in gustatory cortex can respond either exclusively to tastants, exclusively to odorants, or to both (bimodal). Several differences exist between these groups' responses; notably, bimodal neurons code palatability significantly better than unimodal neurons. This group of neurons might represent a substrate for how odorants gain the quality of tastants.
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69
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Measuring the olfactory bulb input-output transformation reveals a contribution to the perception of odorant concentration invariance. Nat Commun 2017; 8:81. [PMID: 28724907 PMCID: PMC5517565 DOI: 10.1038/s41467-017-00036-2] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 05/01/2017] [Indexed: 11/23/2022] Open
Abstract
Humans and other animals can recognize an odorant as the same over a range of odorant concentrations. It remains unclear whether the olfactory bulb, the brain structure that mediates the first stage of olfactory information processing, participates in generating this perceptual concentration invariance. Olfactory bulb glomeruli are regions of neuropil that contain input and output processes: olfactory receptor neuron nerve terminals (input) and mitral/tufted cell apical dendrites (output). Differences between the input and output of a brain region define the function(s) carried out by that region. Here we compare the activity signals from the input and output across a range of odorant concentrations. The output maps maintain a relatively stable representation of odor identity over the tested concentration range, even though the input maps and signals change markedly. These results provide direct evidence that the mammalian olfactory bulb likely participates in generating the perception of concentration invariance of odor quality. Humans and animals recognize an odorant across a range of odorant concentrations, but where in the olfactory processing pathway this invariance is generated is unclear. By measuring and comparing olfactory bulb outputs to inputs, the authors show that the olfactory bulb participates in generating the perception of odorant concentration invariance.
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70
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An Adenosine Receptor for Olfaction in Fish. Curr Biol 2017; 27:1437-1447.e4. [PMID: 28502661 DOI: 10.1016/j.cub.2017.04.014] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 03/14/2017] [Accepted: 04/10/2017] [Indexed: 11/22/2022]
Abstract
Nucleotides released from food sources into environmental water are supposed to act as feeding cues for many fish species. However, it remains unknown how fish can sensitively detect those nucleotides. Here we discover a novel olfactory mechanism for ATP sensing in zebrafish. Upon entering into the nostril, ATP is efficiently converted into adenosine through enzymatic reactions of two ecto-nucleotidases expressed in the olfactory epithelium. Adenosine subsequently activates a small population of olfactory sensory neurons expressing a novel adenosine receptor A2c that is unique to fishes and amphibians. The information is then transmitted to a single glomerulus in the olfactory bulb and further to four regions in higher olfactory centers. These results provide conclusive evidence for a sophisticated enzyme-linked receptor mechanism underlying detection of ATP as a food-derived attractive odorant linking to foraging behavior that is crucial and common to aquatic lower vertebrates.
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71
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Li L, Wojtowicz JL, Malin JH, Huang T, Lee EB, Chen Z. GnRH-mediated olfactory and visual inputs promote mating-like behaviors in male zebrafish. PLoS One 2017; 12:e0174143. [PMID: 28329004 PMCID: PMC5362193 DOI: 10.1371/journal.pone.0174143] [Citation(s) in RCA: 23] [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: 09/07/2016] [Accepted: 03/03/2017] [Indexed: 01/13/2023] Open
Abstract
The engagement of sexual behaviors is regulated by a number of factors which include gene expression, hormone circulation, and multi-sensory information integration. In zebrafish, when a male and a female are placed in the same container, they show mating-like behaviors regardless of whether they are kept together or separated by a net. No mating-like behaviors are observed when same-sex animals are put together. Through the olfacto-visual centrifugal pathway, activation of the terminalis nerve in the olfactory bulb increases GnRH signaling in the brain and triggers mating-like behaviors between males. In zebrafish mutants or wild-type fish in which the olfacto-visual centrifugal pathway is impaired or chemically ablated, in response to odor stimulation the mating-like behaviors between males are no longer evident. Together, the data suggest that the combination of olfactory and visual signals alter male zebrafish's mating-like behaviors via GnRH signaling.
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Affiliation(s)
- Lei Li
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, United States of America
- * E-mail:
| | - Jennifer L. Wojtowicz
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, United States of America
| | - John H. Malin
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, United States of America
| | - Tao Huang
- Center for Reproductive Medicine, Shandong University, Jinan,China
| | - Eric B. Lee
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, United States of America
| | - Zijiang Chen
- Center for Reproductive Medicine, Shandong University, Jinan,China
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72
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Green WW, Boyes K, McFadden C, Daghfous G, Auclair F, Zhang H, Li W, Dubuc R, Zielinski BS. Odorant organization in the olfactory bulb of the sea lamprey. ACTA ACUST UNITED AC 2017; 220:1350-1359. [PMID: 28183864 DOI: 10.1242/jeb.150466] [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] [Received: 09/27/2016] [Accepted: 01/27/2017] [Indexed: 11/20/2022]
Abstract
Olfactory sensory neurons innervate the olfactory bulb, where responses to different odorants generate a chemotopic map of increased neural activity within different bulbar regions. In this study, insight into the basal pattern of neural organization of the vertebrate olfactory bulb was gained by investigating the lamprey. Retrograde labelling established that lateral and dorsal bulbar territories receive the axons of sensory neurons broadly distributed in the main olfactory epithelium and that the medial region receives sensory neuron input only from neurons projecting from the accessory olfactory organ. The response duration for local field potential recordings was similar in the lateral and dorsal regions, and both were longer than medial responses. All three regions responded to amino acid odorants. The dorsal and medial regions, but not the lateral region, responded to steroids. These findings show evidence for olfactory streams in the sea lamprey olfactory bulb: the lateral region responds to amino acids from sensory input in the main olfactory epithelium, the dorsal region responds to steroids (taurocholic acid and pheromones) and to amino acids from sensory input in the main olfactory epithelium, and the medial bulbar region responds to amino acids and steroids stimulating the accessory olfactory organ. These findings indicate that olfactory subsystems are present at the base of vertebrate evolution and that regionality in the lamprey olfactory bulb has some aspects previously seen in other vertebrate species.
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Affiliation(s)
- Warren W Green
- Department of Biological Sciences, University of Windsor, Windsor, ON, Canada N9B3P4
| | - Karl Boyes
- Department of Biological Sciences, University of Windsor, Windsor, ON, Canada N9B3P4
| | - Charrie McFadden
- Department of Biological Sciences, University of Windsor, Windsor, ON, Canada N9B3P4
| | - Gheylen Daghfous
- Groupe de Recherche en Activité Physique Adaptée, Département des sciences de l'activité physique, Université du Québec à Montréal, Montréal, QC, Canada H3C3P8.,Groupe de Recherche sur le Système Nerveux Central, Département de neurosciences, Université de Montréal, Montréal, QC, Canada H3C3J7
| | - François Auclair
- Groupe de Recherche en Activité Physique Adaptée, Département des sciences de l'activité physique, Université du Québec à Montréal, Montréal, QC, Canada H3C3P8.,Groupe de Recherche sur le Système Nerveux Central, Département de neurosciences, Université de Montréal, Montréal, QC, Canada H3C3J7
| | - Huiming Zhang
- Department of Biological Sciences, University of Windsor, Windsor, ON, Canada N9B3P4
| | - Weiming Li
- Department of Fisheries and Wildlife, Michigan State University, East Lansing, MI 48824, USA
| | - Réjean Dubuc
- Groupe de Recherche en Activité Physique Adaptée, Département des sciences de l'activité physique, Université du Québec à Montréal, Montréal, QC, Canada H3C3P8.,Groupe de Recherche sur le Système Nerveux Central, Département de neurosciences, Université de Montréal, Montréal, QC, Canada H3C3J7
| | - Barbara S Zielinski
- Department of Biological Sciences, University of Windsor, Windsor, ON, Canada N9B3P4 .,Great Lakes Institute for Environmental Research, University of Windsor, Windsor, ON, Canada N9B3P4
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73
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Ochs CL, Suntres T, Zygowska A, Pitcher T, Zielinski BS. Organization of glomerular territories in the olfactory bulb of post-embryonic wild chinook salmonOncorhynchus tshawytscha. J Morphol 2017; 278:464-474. [DOI: 10.1002/jmor.20641] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 12/01/2016] [Accepted: 12/04/2016] [Indexed: 12/30/2022]
Affiliation(s)
- Cory L. Ochs
- Department of Biological Sciences; University of Windsor; 401 Sunset Avenue Windsor Ontario Canada N9B 3P4
| | - Tina Suntres
- Department of Biological Sciences; University of Windsor; 401 Sunset Avenue Windsor Ontario Canada N9B 3P4
| | - Alexandra Zygowska
- Department of Biological Sciences; University of Windsor; 401 Sunset Avenue Windsor Ontario Canada N9B 3P4
| | - Trevor Pitcher
- Department of Biological Sciences; University of Windsor; 401 Sunset Avenue Windsor Ontario Canada N9B 3P4
- Great Lakes Institute for Environmental Research, University of Windsor; 2990 Riverside Dr. W. Windsor Ontario N9C 1A2
| | - Barbara S. Zielinski
- Department of Biological Sciences; University of Windsor; 401 Sunset Avenue Windsor Ontario Canada N9B 3P4
- Great Lakes Institute for Environmental Research, University of Windsor; 2990 Riverside Dr. W. Windsor Ontario N9C 1A2
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74
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Ko HJ, Park TH. Bioelectronic nose and its application to smell visualization. J Biol Eng 2016; 10:17. [PMID: 27999616 PMCID: PMC5154139 DOI: 10.1186/s13036-016-0041-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 12/05/2016] [Indexed: 11/10/2022] Open
Abstract
There have been many trials to visualize smell using various techniques in order to objectively express the smell because information obtained from the sense of smell in human is very subjective. So far, well-trained experts such as a perfumer, complex and large-scale equipment such as GC-MS, and an electronic nose have played major roles in objectively detecting and recognizing odors. Recently, an optoelectronic nose was developed to achieve this purpose, but some limitations regarding the sensitivity and the number of smells that can be visualized still persist. Since the elucidation of the olfactory mechanism, numerous researches have been accomplished for the development of a sensing device by mimicking human olfactory system. Engineered olfactory cells were constructed to mimic the human olfactory system, and the use of engineered olfactory cells for smell visualization has been attempted with the use of various methods such as calcium imaging, CRE reporter assay, BRET, and membrane potential assay; however, it is not easy to consistently control the condition of cells and it is impossible to detect low odorant concentration. Recently, the bioelectronic nose was developed, and much improved along with the improvement of nano-biotechnology. The bioelectronic nose consists of the following two parts: primary transducer and secondary transducer. Biological materials as a primary transducer improved the selectivity of the sensor, and nanomaterials as a secondary transducer increased the sensitivity. Especially, the bioelectronic noses using various nanomaterials combined with human olfactory receptors or nanovesicles derived from engineered olfactory cells have a potential which can detect almost all of the smells recognized by human because an engineered olfactory cell might be able to express any human olfactory receptor as well as can mimic human olfactory system. Therefore, bioelectronic nose will be a potent tool for smell visualization, but only if two technologies are completed. First, a multi-channel array-sensing system has to be applied for the integration of all of the olfactory receptors into a single chip for mimicking the performance of human nose. Second, the processing technique of the multi-channel system signals should be simultaneously established with the conversion of the signals to visual images. With the use of this latest sensing technology, the realization of a proper smell-visualization technology is expected in the near future.
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Affiliation(s)
- Hwi Jin Ko
- Bio-MAX Institute, Seoul, 151-742 Republic of Korea
| | - Tai Hyun Park
- Bio-MAX Institute, Seoul, 151-742 Republic of Korea ; School of Chemical and Biological Engineering, Seoul National University, Seoul, 151-742 Republic of Korea ; Advanced Institutes of Convergence Technology, Suwon, Gyeonggido 443-270 Republic of Korea
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75
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Wanner AA, Genoud C, Friedrich RW. 3-dimensional electron microscopic imaging of the zebrafish olfactory bulb and dense reconstruction of neurons. Sci Data 2016; 3:160100. [PMID: 27824337 PMCID: PMC5100684 DOI: 10.1038/sdata.2016.100] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 09/22/2016] [Indexed: 01/27/2023] Open
Abstract
Large-scale reconstructions of neuronal populations are critical for structural analyses of neuronal cell types and circuits. Dense reconstructions of neurons from image data require ultrastructural resolution throughout large volumes, which can be achieved by automated volumetric electron microscopy (EM) techniques. We used serial block face scanning EM (SBEM) and conductive sample embedding to acquire an image stack from an olfactory bulb (OB) of a zebrafish larva at a voxel resolution of 9.25×9.25×25 nm3. Skeletons of 1,022 neurons, 98% of all neurons in the OB, were reconstructed by manual tracing and efficient error correction procedures. An ergonomic software package, PyKNOSSOS, was created in Python for data browsing, neuron tracing, synapse annotation, and visualization. The reconstructions allow for detailed analyses of morphology, projections and subcellular features of different neuron types. The high density of reconstructions enables geometrical and topological analyses of the OB circuitry. Image data can be accessed and viewed through the neurodata web services (http://www.neurodata.io). Raw data and reconstructions can be visualized in PyKNOSSOS.
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Affiliation(s)
- Adrian A. Wanner
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
- University of Basel, 4003 Basel, Switzerland
| | - Christel Genoud
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Rainer W. Friedrich
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
- University of Basel, 4003 Basel, Switzerland
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76
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Thompson AW, Scott EK. Characterisation of sensitivity and orientation tuning for visually responsive ensembles in the zebrafish tectum. Sci Rep 2016; 6:34887. [PMID: 27713561 PMCID: PMC5054398 DOI: 10.1038/srep34887] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 09/19/2016] [Indexed: 01/23/2023] Open
Abstract
Sensory coding relies on ensembles of co-active neurons, but these ensembles change from trial to trial of the same stimulus. This is due in part to wide variability in the responsiveness of neurons within these ensembles, with some neurons responding regularly to a stimulus while others respond inconsistently. The specific functional properties that cause neurons to respond more or less consistently have not been thoroughly explored. Here, we have examined neuronal ensembles in the zebrafish tectum responsive to repeated presentations of a visual stimulus, and have explored how these populations change when the orientation or brightness of the stimulus is altered. We found a continuum of response probabilities across the neurons in the visual ensembles, with the most responsive neurons focused toward the spatial centre of the ensemble. As the visual stimulus was made dimmer, these neurons remained active, suggesting higher overall responsiveness. However, these cells appeared to represent the most consistent end of a continuum, rather than a functionally distinct “core” of highly responsive neurons. Reliably responsive cells were broadly tuned to a range of stimulus orientations suggesting that, at least for this stimulus property, tight stimulus tuning was not responsible for their consistent responses.
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Affiliation(s)
- A W Thompson
- School of Biomedical Sciences The University of Queensland, St Lucia, QLD, 4072, Australia
| | - E K Scott
- School of Biomedical Sciences The University of Queensland, St Lucia, QLD, 4072, Australia.,The Queensland Brain Institute, The University of Queensland, St Lucia, QLD, 4072, Australia
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77
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Roberts AC, Pearce KC, Choe RC, Alzagatiti JB, Yeung AK, Bill BR, Glanzman DL. Long-term habituation of the C-start escape response in zebrafish larvae. Neurobiol Learn Mem 2016; 134 Pt B:360-8. [PMID: 27555232 DOI: 10.1016/j.nlm.2016.08.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 08/10/2016] [Accepted: 08/18/2016] [Indexed: 01/01/2023]
Abstract
The cellular and molecular basis of long-term memory in vertebrates remains poorly understood. Knowledge regarding long-term memory has been impeded by the enormous complexity of the vertebrate brain, particularly the mammalian brain, as well as by the relative complexity of the behavioral alterations examined in most studies of long-term memory in vertebrates. Here, we demonstrate a long-term form of nonassociative learning-specifically, long-term habituation (LTH)-of a simple reflexive escape response, the C-start, in zebrafish larvae. The C-start is triggered by the activation of one of a pair of giant neurons in the zebrafish's hindbrain, the Mauthner cells. We show that LTH of the C-start requires the activity of NMDA receptors and involves macromolecular synthesis. We further show that the long-term habituated reflex can by rapidly dishabituated by a brief tactile stimulus. Our results set the stage for rigorous, mechanistic investigations of the long-term memory for habituation of a reflexive behavioral response, one that is mediated by a relatively simple, neurobiologically tractable, neural circuit. Moreover, the demonstration of NMDAR and transcriptionally dependent LTH in a translucent vertebrate organism should facilitate the use of optical recording, and optogenetic manipulation, of neuronal activity to elucidate the cellular basis of a long-term vertebrate memory.
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Affiliation(s)
- Adam C Roberts
- Department of Integrative Biology and Physiology, University of California Los Angeles, Los Angeles, CA, United States
| | - Kaycey C Pearce
- Department of Integrative Biology and Physiology, University of California Los Angeles, Los Angeles, CA, United States
| | - Ronny C Choe
- Department of Integrative Biology and Physiology, University of California Los Angeles, Los Angeles, CA, United States
| | - Joseph B Alzagatiti
- Department of Integrative Biology and Physiology, University of California Los Angeles, Los Angeles, CA, United States
| | - Anthony K Yeung
- Department of Integrative Biology and Physiology, University of California Los Angeles, Los Angeles, CA, United States
| | - Brent R Bill
- Center for Autism Research and Program in Neurobehavioral Genetics, Semel Institute for Neuroscience and Human Behavior at UCLA, Los Angeles, CA, United States; Department of Psychiatry, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States; Department of Biology, University of Texas at Tyler, Tyler, TX, United States
| | - David L Glanzman
- Department of Integrative Biology and Physiology, University of California Los Angeles, Los Angeles, CA, United States; Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States; Integrative Center for Learning and Memory, Brain Research Institute, University of California Los Angeles, Los Angeles, CA, United States.
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78
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Decoding of Context-Dependent Olfactory Behavior in Drosophila. Neuron 2016; 91:155-67. [PMID: 27321924 DOI: 10.1016/j.neuron.2016.05.022] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Revised: 03/22/2016] [Accepted: 05/11/2016] [Indexed: 11/23/2022]
Abstract
Odor information is encoded in the activity of a population of glomeruli in the primary olfactory center. However, how this information is decoded in the brain remains elusive. Here, we address this question in Drosophila by combining neuronal imaging and tracking of innate behavioral responses. We find that the behavior is accurately predicted by a model summing normalized glomerular responses, in which each glomerulus contributes a specific, small amount to odor preference. This model is further supported by targeted manipulations of glomerular input, which biased the behavior. Additionally, we observe that relative odor preference changes and can even switch depending on the context, an effect correctly predicted by our normalization model. Our results indicate that olfactory information is decoded from the pooled activity of a glomerular repertoire and demonstrate the ability of the olfactory system to adapt to the statistics of its environment.
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79
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80
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Olfactory receptor for prostaglandin F2α mediates male fish courtship behavior. Nat Neurosci 2016; 19:897-904. [PMID: 27239939 DOI: 10.1038/nn.4314] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 04/29/2016] [Indexed: 02/02/2023]
Abstract
Pheromones play vital roles for survival and reproduction in various organisms. In many fishes, prostaglandin F2α acts not only as a female reproductive hormone, facilitating ovulation and spawning, but also as a sex pheromone inducing male reproductive behaviors. Here, we unravel the molecular and neural circuit mechanisms underlying the pheromonal action of prostaglandin F2α in zebrafish. Prostaglandin F2α specifically activates two olfactory receptors with different sensitivities and expression in distinct populations of ciliated olfactory sensory neurons. Pheromone information is then transmitted to two ventromedial glomeruli in the olfactory bulb and further to four regions in higher olfactory centers. Mutant male zebrafish deficient in the high-affinity receptor exhibit loss of attractive response to prostaglandin F2α and impairment of courtship behaviors toward female fish. These findings demonstrate the functional significance and activation of selective neural circuitry for the sex pheromone prostaglandin F2α and its cognate olfactory receptor in fish reproductive behavior.
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81
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Berck ME, Khandelwal A, Claus L, Hernandez-Nunez L, Si G, Tabone CJ, Li F, Truman JW, Fetter RD, Louis M, Samuel AD, Cardona A. The wiring diagram of a glomerular olfactory system. eLife 2016; 5. [PMID: 27177418 PMCID: PMC4930330 DOI: 10.7554/elife.14859] [Citation(s) in RCA: 116] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Accepted: 05/06/2016] [Indexed: 12/12/2022] Open
Abstract
The sense of smell enables animals to react to long-distance cues according to learned and innate valences. Here, we have mapped with electron microscopy the complete wiring diagram of the Drosophila larval antennal lobe, an olfactory neuropil similar to the vertebrate olfactory bulb. We found a canonical circuit with uniglomerular projection neurons (uPNs) relaying gain-controlled ORN activity to the mushroom body and the lateral horn. A second, parallel circuit with multiglomerular projection neurons (mPNs) and hierarchically connected local neurons (LNs) selectively integrates multiple ORN signals already at the first synapse. LN-LN synaptic connections putatively implement a bistable gain control mechanism that either computes odor saliency through panglomerular inhibition, or allows some glomeruli to respond to faint aversive odors in the presence of strong appetitive odors. This complete wiring diagram will support experimental and theoretical studies towards bridging the gap between circuits and behavior. DOI:http://dx.doi.org/10.7554/eLife.14859.001 Our sense of smell can tell us about bread being baked faraway in the kitchen, or whether a leftover piece finally went bad. Similarly to the eyes, the nose enables us to make up a mental image of what lies at a distance. In mammals, the surface of the nose hosts a huge number of olfactory sensory cells, each of which is tuned to respond to a small set of scent molecules. The olfactory sensory cells communicate with a region of the brain called the olfactory bulb. Olfactory sensory cells of the same type converge onto the same small pocket of the olfactory bulb, forming a structure called a glomerulus. Similarly to how the retina generates an image, the combined activity of multiple glomeruli defines an odor. A particular smell is the combination of many volatile compounds, the odorants. Therefore the interactions between different olfactory glomeruli are important for defining the nature of the perceived odor. Although the types of neurons involved in these interactions were known in insects, fish and mice, a precise wiring diagram of a complete set of glomeruli had not been described. In particular, the points of contact through which neurons communicate with each other – known as synapses – among all the neurons participating in an olfactory system were not known. Berck, Khandelwal et al. have now taken advantage of the small size of the olfactory system of the larvae of Drosophila fruit flies to fully describe, using high-resolution imaging, all its neurons and their synapses. The results define the complete wiring diagram of the neural circuit that processes the signals sent by olfactory sensory neurons in the larva’s olfactory circuits. In addition to the neurons that read out the activity of a single glomerulus and send it to higher areas of the brain for further processing, there are also numerous neurons that read out activity from multiple glomeruli. These neurons represent a system, encoded in the genome, for quickly extracting valuable olfactory information and then relaying it to other areas of the brain. An essential aspect of sensation is the ability to stop noticing a stimulus if it doesn't change. This allows an animal to, for example, find food by moving in a direction that increases the intensity of an odor. Inhibition mediates some aspects of this capability. The discovery of structure in the inhibitory connections among glomeruli, together with prior findings on the inner workings of the olfactory system, enabled Berck, Khandelwal et al. to hypothesize how the olfactory circuits enable odor gradients to be navigated. Further investigation revealed more about how the circuits could detect slight changes in odor concentration regardless of whether the overall odor intensity is strong or faint. And, crucially, it revealed how the worst odors – which can signal danger – can still be perceived in the presence of very strong pleasant odors. With the wiring diagram, theories about the sense of smell can now be tested using the genetic tools available for Drosophila, leading to an understanding of how neural circuits work. DOI:http://dx.doi.org/10.7554/eLife.14859.002
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Affiliation(s)
- Matthew E Berck
- Department of Physics, Harvard University, Cambridge, United States.,Center for Brain Science, Harvard University, Cambridge, United States
| | - Avinash Khandelwal
- EMBL-CRG Systems Biology Program, Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, Barcelona, Spain.,Universitat Pompeu Fabra, Barcelona, Spain
| | - Lindsey Claus
- Department of Physics, Harvard University, Cambridge, United States.,Center for Brain Science, Harvard University, Cambridge, United States
| | - Luis Hernandez-Nunez
- Department of Physics, Harvard University, Cambridge, United States.,Center for Brain Science, Harvard University, Cambridge, United States
| | - Guangwei Si
- Department of Physics, Harvard University, Cambridge, United States.,Center for Brain Science, Harvard University, Cambridge, United States
| | | | - Feng Li
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - James W Truman
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Rick D Fetter
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Matthieu Louis
- EMBL-CRG Systems Biology Program, Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, Barcelona, Spain.,Universitat Pompeu Fabra, Barcelona, Spain
| | - Aravinthan Dt Samuel
- Department of Physics, Harvard University, Cambridge, United States.,Center for Brain Science, Harvard University, Cambridge, United States
| | - Albert Cardona
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
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82
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Wanner AA, Genoud C, Masudi T, Siksou L, Friedrich RW. Dense EM-based reconstruction of the interglomerular projectome in the zebrafish olfactory bulb. Nat Neurosci 2016; 19:816-25. [PMID: 27089019 DOI: 10.1038/nn.4290] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 03/22/2016] [Indexed: 12/12/2022]
Abstract
The dense reconstruction of neuronal circuits from volumetric electron microscopy (EM) data has the potential to uncover fundamental structure-function relationships in the brain. To address bottlenecks in the workflow of this emerging methodology, we developed a procedure for conductive sample embedding and a pipeline for neuron reconstruction. We reconstructed ∼98% of all neurons (>1,000) in the olfactory bulb of a zebrafish larva with high accuracy and annotated all synapses on subsets of neurons representing different types. The organization of the larval olfactory bulb showed marked differences from that of the adult but similarities to that of the insect antennal lobe. Interneurons comprised multiple types but granule cells were rare. Interglomerular projections of interneurons were complex and bidirectional. Projections were not random but biased toward glomerular groups receiving input from common types of sensory neurons. Hence, the interneuron network in the olfactory bulb exhibits a specific topological organization that is governed by glomerular identity.
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Affiliation(s)
- Adrian A Wanner
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Christel Genoud
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Tafheem Masudi
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Léa Siksou
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Rainer W Friedrich
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland.,University of Basel, Basel, Switzerland
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83
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Daly KC, Bradley S, Chapman PD, Staudacher EM, Tiede R, Schachtner J. Space Takes Time: Concentration Dependent Output Codes from Primary Olfactory Networks Rapidly Provide Additional Information at Defined Discrimination Thresholds. Front Cell Neurosci 2016; 9:515. [PMID: 26834563 PMCID: PMC4712294 DOI: 10.3389/fncel.2015.00515] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Accepted: 12/22/2015] [Indexed: 11/13/2022] Open
Abstract
As odor concentration increases, primary olfactory network representations expand in spatial distribution, temporal complexity and duration. However, the direct relationship between concentration dependent odor representations and the psychophysical thresholds of detection and discrimination is poorly understood. This relationship is absolutely critical as thresholds signify transition points whereby representations become meaningful to the organism. Here, we matched stimulus protocols for psychophysical assays and intracellular recordings of antennal lobe (AL) projection neurons (PNs) in the moth Manduca sexta to directly compare psychophysical thresholds and the output representations they elicit. We first behaviorally identified odor detection and discrimination thresholds across an odor dilution series for a panel of structurally similar odors. We then characterized spatiotemporal spiking patterns across a population of individually filled and identified AL PNs in response to those odors at concentrations below, at, and above identified thresholds. Using spatial and spatiotemporal based analyses we observed that each stimulus produced unique representations, even at sub-threshold concentrations. Mean response latency did not decrease and the percent glomerular activation did not increase with concentration until undiluted odor. Furthermore, correlations between spatial patterns for odor decreased, but only significantly with undiluted odor. Using time-integrated Euclidean distance (ED) measures, we determined that added spatiotemporal information was present at the discrimination but not detection threshold. This added information was evidenced by an increase in integrated distance between the sub-detection and discrimination threshold concentrations (of the same odor) that was not present in comparison of the sub-detection and detection threshold. After consideration of delays for information to reach the AL we find that it takes ~120-140 ms for the AL to output identity information. Overall, these results demonstrate that as odor concentration increases, added information about odor identity is embedded in the spatiotemporal representation at the discrimination threshold.
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Affiliation(s)
- Kevin C Daly
- Department of Biology, West Virginia University Morgantown, WV, USA
| | - Samual Bradley
- Department of Biology, West Virginia University Morgantown, WV, USA
| | | | | | - Regina Tiede
- Fachbereich Biologie, Philipps-Universität Marburg, Germany
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84
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Sanganahalli BG, Rebello MR, Herman P, Papademetris X, Shepherd GM, Verhagen JV, Hyder F. Comparison of glomerular activity patterns by fMRI and wide-field calcium imaging: Implications for principles underlying odor mapping. Neuroimage 2015; 126:208-18. [PMID: 26631819 DOI: 10.1016/j.neuroimage.2015.11.048] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Revised: 11/18/2015] [Accepted: 11/20/2015] [Indexed: 10/22/2022] Open
Abstract
Functional imaging signals arise from distinct metabolic and hemodynamic events at the neuropil, but how these processes are influenced by pre- and post-synaptic activities need to be understood for quantitative interpretation of stimulus-evoked mapping data. The olfactory bulb (OB) glomeruli, spherical neuropil regions with well-defined neuronal circuitry, can provide insights into this issue. Optical calcium-sensitive fluorescent dye imaging (OICa(2+)) reflects dynamics of pre-synaptic input to glomeruli, whereas high-resolution functional magnetic resonance imaging (fMRI) using deoxyhemoglobin contrast reveals neuropil function within the glomerular layer where both pre- and post-synaptic activities contribute. We imaged odor-specific activity patterns of the dorsal OB in the same anesthetized rats with fMRI and OICa(2+) and then co-registered the respective maps to compare patterns in the same space. Maps by each modality were very reproducible as trial-to-trial patterns for a given odor, overlapping by ~80%. Maps evoked by ethyl butyrate and methyl valerate for a given modality overlapped by ~80%, suggesting activation of similar dorsal glomerular networks by these odors. Comparison of maps generated by both methods for a given odor showed ~70% overlap, indicating similar odor-specific maps by each method. These results suggest that odor-specific glomerular patterns by high-resolution fMRI primarily tracks pre-synaptic input to the OB. Thus combining OICa(2+) and fMRI lays the framework for studies of OB processing over a range of spatiotemporal scales, where OICa(2+) can feature the fast dynamics of dorsal glomerular clusters and fMRI can map the entire glomerular sheet in the OB.
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Affiliation(s)
- Basavaraju G Sanganahalli
- Magnetic Resonance Research Center (MRRC), Yale University, New Haven, CT, USA; Quantitative Neuroscience with Magnetic Resonance (QNMR) Core Center, Yale University, New Haven, CT, USA; Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA.
| | - Michelle R Rebello
- Department of Neurobiology, Yale University, New Haven, CT, USA; The John B. Pierce Laboratory, New Haven, CT, USA
| | - Peter Herman
- Magnetic Resonance Research Center (MRRC), Yale University, New Haven, CT, USA; Quantitative Neuroscience with Magnetic Resonance (QNMR) Core Center, Yale University, New Haven, CT, USA; Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA
| | - Xenophon Papademetris
- Quantitative Neuroscience with Magnetic Resonance (QNMR) Core Center, Yale University, New Haven, CT, USA; Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA; Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | | | - Justus V Verhagen
- Department of Neurobiology, Yale University, New Haven, CT, USA; The John B. Pierce Laboratory, New Haven, CT, USA.
| | - Fahmeed Hyder
- Magnetic Resonance Research Center (MRRC), Yale University, New Haven, CT, USA; Quantitative Neuroscience with Magnetic Resonance (QNMR) Core Center, Yale University, New Haven, CT, USA; Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, USA; Department of Biomedical Engineering, Yale University, New Haven, CT, USA.
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85
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Hansson KA, Døving KB, Skjeldal FM. Mixed input to olfactory glomeruli from two subsets of ciliated sensory neurons does not impede relay neuron specificity in the crucian carp. ACTA ACUST UNITED AC 2015; 218:3257-63. [PMID: 26347551 DOI: 10.1242/jeb.125476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 08/19/2015] [Indexed: 11/20/2022]
Abstract
The consensus view of olfactory processing is that the axons of receptor-specific primary olfactory sensory neurons (OSNs) converge to a small subset of glomeruli, thus preserving the odour identity before the olfactory information is processed in higher brain centres. In the present study, we show that two different subsets of ciliated OSNs with different odorant specificities converge to the same glomeruli. In order to stain different ciliated OSNs in the crucian carp Carassius carassius we used two different chemical odorants, a bile salt and a purported alarm substance, together with fluorescent dextrans. The dye is transported within the axons and stains glomeruli in the olfactory bulb. Interestingly, the axons from the ciliated OSNs co-converge to the same glomeruli. Despite intermingled innervation of glomeruli, axons and terminal fields from the two different subsets of ciliated OSNs remained mono-coloured. By 4-6 days after staining, the dye was transported trans-synaptically to separately stained axons of relay neurons. These findings demonstrate that specificity of the primary neurons is retained in the olfactory pathways despite mixed innervation of the olfactory glomeruli. The results are discussed in relation to the emerging concepts about non-mammalian glomeruli.
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Affiliation(s)
| | - Kjell B Døving
- Department of Biosciences, University of Oslo, Oslo N-0316, Norway
| | - Frode M Skjeldal
- Department of Biosciences, University of Oslo, Oslo N-0316, Norway
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86
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Whitlock KE. The loss of scents: do defects in olfactory sensory neuron development underlie human disease? ACTA ACUST UNITED AC 2015; 105:114-25. [PMID: 26111003 DOI: 10.1002/bdrc.21094] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Accepted: 05/12/2015] [Indexed: 12/20/2022]
Abstract
The olfactory system is a fascinating and beguiling sensory system: olfactory sensory neurons detect odors underlying behaviors essential for mate choice, food selection, and escape from predators, among others. These sensory neurons are unique in that they have dendrites contacting the outside world, yet their first synapse lies in the central nervous system. The information entering the central nervous system is used to create odor memories that play a profound role in recognition of individuals, places, and appropriate foods. Here, the structure of the olfactory epithelium is given as an overview to discuss the origin of the olfactory placode, the plasticity of the olfactory sensory neurons, and finally the origins of the gonadotropin-releasing hormone neuroendocrine cells. For the purposes of this review, the development of the peripheral sensory system will be analyzed, incorporating recently published studies highlighting the potential novelties in development mechanisms. Specifically, an emerging model where the olfactory epithelium and olfactory bulb develop simultaneously from a continuous neurectoderm patterned at the end of gastrulation, and the multiple origins of the gonadotropin-releasing hormone neuroendocrine cells associated with the olfactory sensory system development will be presented. Advances in the understanding of the basic mechanisms underlying olfactory sensory system development allows for a more thorough understanding of the potential causes of human disease.
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Affiliation(s)
- Kathleen E Whitlock
- Centro Interdisciplinario de Neurociencia de Valparaíso (CINV), Facultad de Ciencias, Universidad de Valparaiso, Valparaiso, Chile
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87
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Wyatt C, Bartoszek EM, Yaksi E. Methods for studying the zebrafish brain: past, present and future. Eur J Neurosci 2015; 42:1746-63. [PMID: 25900095 DOI: 10.1111/ejn.12932] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Revised: 04/16/2015] [Accepted: 04/20/2015] [Indexed: 01/16/2023]
Abstract
The zebrafish (Danio rerio) is one of the most promising new model organisms. The increasing popularity of this amazing small vertebrate is evident from the exponentially growing numbers of research articles, funded projects and new discoveries associated with the use of zebrafish for studying development, brain function, human diseases and screening for new drugs. Thanks to the development of novel technologies, the range of zebrafish research is constantly expanding with new tools synergistically enhancing traditional techniques. In this review we will highlight the past and present techniques which have made, and continue to make, zebrafish an attractive model organism for various fields of biology, with a specific focus on neuroscience.
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Affiliation(s)
- Cameron Wyatt
- Neuro-Electronics Research Flanders, Imec Campus, Kapeldreef, Leuven, Belgium.,VIB, Leuven, Belgium
| | - Ewelina M Bartoszek
- Neuro-Electronics Research Flanders, Imec Campus, Kapeldreef, Leuven, Belgium.,VIB, Leuven, Belgium.,Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Norwegian University of Science and Technology, Trondheim, Norway
| | - Emre Yaksi
- Neuro-Electronics Research Flanders, Imec Campus, Kapeldreef, Leuven, Belgium.,VIB, Leuven, Belgium.,KU Leuven, Leuven, Belgium.,Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Norwegian University of Science and Technology, Trondheim, Norway
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88
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Monitoring brain activity with protein voltage and calcium sensors. Sci Rep 2015; 5:10212. [PMID: 25970202 PMCID: PMC4429559 DOI: 10.1038/srep10212] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 04/07/2015] [Indexed: 11/08/2022] Open
Abstract
Understanding the roles of different cell types in the behaviors generated by neural circuits requires protein indicators that report neural activity with high spatio-temporal resolution. Genetically encoded fluorescent protein (FP) voltage sensors, which optically report the electrical activity in distinct cell populations, are, in principle, ideal candidates. Here we demonstrate that the FP voltage sensor ArcLight reports odor-evoked electrical activity in the in vivo mammalian olfactory bulb in single trials using both wide-field and 2-photon imaging. ArcLight resolved fast odorant-responses in individual glomeruli, and distributed odorant responses across a population of glomeruli. Comparisons between ArcLight and the protein calcium sensors GCaMP3 and GCaMP6f revealed that ArcLight had faster temporal kinetics that more clearly distinguished activity elicited by individual odorant inspirations. In contrast, the signals from both GCaMPs were a saturating integral of activity that returned relatively slowly to the baseline. ArcLight enables optical electrophysiology of mammalian neuronal population activity in vivo.
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89
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Abstract
Animals need to discriminate differences in spatiotemporally distributed sensory signals in terms of quality as well as quantity for generating adaptive behavior. Olfactory signals characterized by odor identity and concentration are intermittently distributed in the environment. From these intervals of stimulation, animals process odorant concentration to localize partners or food sources. Although concentration-response characteristics in olfactory neurons have traditionally been investigated using single stimulus pulses, their behavior under intermittent stimulus regimens remains largely elusive. Using the silkmoth (Bombyx mori) pheromone processing system, a simple and behaviorally well-defined model for olfaction, we investigated the neuronal representation of odorant concentration upon intermittent stimulation in the naturally occurring range. To the first stimulus in a series, the responses of antennal lobe (AL) projection neurons (PNs) showed a concentration dependence as previously shown in many olfactory systems. However, PN response amplitudes dynamically changed upon exposure to intermittent stimuli of the same odorant concentration and settled to a constant, largely concentration-independent level. As a result, PN responses emphasized odorant concentration changes rather than encoding absolute concentration in pulse trains of stimuli. Olfactory receptor neurons did not contribute to this response transformation which was due to long-lasting inhibition affecting PNs in the AL. Simulations confirmed that inhibition also provides advantages when stimuli have naturalistic properties. The primary olfactory center thus functions as an odorant concentration differentiator to efficiently detect concentration changes, thereby improving odorant source orientation over a wide concentration range.
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90
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Ahuja G, Korsching S. Zebrafish olfactory receptor ORA1 recognizes a putative reproductive pheromone. Commun Integr Biol 2014; 7:970501. [PMID: 26842458 PMCID: PMC4594460 DOI: 10.4161/19420889.2014.970501] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Accepted: 09/03/2014] [Indexed: 02/03/2023] Open
Abstract
Teleost v1r-related ora genes constitute a small and
highly conserved olfactory receptor gene family, and their direct orthologs are present in
lineages as distant as cartilaginous fishes. Recently, the first member of the
ora gene family was deorphanized. ORA1 detects p-hydroxyphenylacetic
acid with high sensitivity and specificity. This compound elicits olfactory-mediated
oviposition behavior in adult zebrafish mating pairs, suggesting a potential function as a
reproductive pheromone for pHPAA itself or a related substance. This association of an
odor and its cognate receptor with an oviposition response may provide a molecular basis
for studying neural circuits involved in fish reproduction.
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Affiliation(s)
- Gaurav Ahuja
- Institute for Genetics; University at Cologne ; Cologne, Germany
| | - Sigrun Korsching
- Institute for Genetics; University at Cologne ; Cologne, Germany
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91
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White EJ, Kounelis SK, Byrd-Jacobs CA. Plasticity of glomeruli and olfactory-mediated behavior in zebrafish following detergent lesioning of the olfactory epithelium. Neuroscience 2014; 284:622-631. [PMID: 25450960 DOI: 10.1016/j.neuroscience.2014.10.036] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 10/10/2014] [Accepted: 10/21/2014] [Indexed: 10/24/2022]
Abstract
The zebrafish olfactory system is a valuable model for examining neural regeneration after damage due to the remarkable plasticity of this sensory system and of fish species. We applied detergent to the olfactory organ and examined the effects on both morphology and function of the olfactory system in adult zebrafish. Olfactory organs were treated once with Triton X-100 unilaterally to study glomerular innervation patterns or bilaterally to study odor detection. Fish were allowed to recover for 4-10 days and were compared to untreated control fish. Axonal projections were analyzed using whole mount immunocytochemistry with anti-keyhole limpet hemocyanin, a marker of olfactory axons in teleosts. Chemical lesioning of the olfactory organ with a single dose of Triton X-100 had profound effects on glomerular distribution in the olfactory bulb at 4 days after treatment, with the most significant effects in the medial region of the bulb. Glomeruli had returned by 7 days post-treatment. Analysis of the ability of the fish to detect cocktails of amino acids or bile salts consisted of counting the number of turns the fish made before and after odorant delivery. Control fish turned more after exposure to both odorants. Fish tested 4 and 7 days after chemical lesioning made more turns in response to amino acids but did not respond to bile salts. At 10 days post-lesion, these fish had regained the ability to detect bile salts. Thus, the changes seen in bulbar innervation patterns correlated to odorant-mediated behavior. We show that the adult zebrafish brain has the capacity to recover rapidly from detergent damage of the olfactory epithelium, with both glomerular distribution and odorant-mediated behavior returning in 10 days.
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Affiliation(s)
- E J White
- Department of Biological Sciences, Western Michigan University, 1903 West Michigan Avenue, Kalamazoo, MI 49008-5410, USA.
| | - S K Kounelis
- Department of Biological Sciences, Western Michigan University, 1903 West Michigan Avenue, Kalamazoo, MI 49008-5410, USA.
| | - C A Byrd-Jacobs
- Department of Biological Sciences, Western Michigan University, 1903 West Michigan Avenue, Kalamazoo, MI 49008-5410, USA.
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92
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93
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Syed AS, Korsching SI. Positive Darwinian selection in the singularly large taste receptor gene family of an 'ancient' fish, Latimeria chalumnae. BMC Genomics 2014; 15:650. [PMID: 25091523 PMCID: PMC4132921 DOI: 10.1186/1471-2164-15-650] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Accepted: 07/29/2014] [Indexed: 11/11/2022] Open
Abstract
Background Chemical senses are one of the foremost means by which organisms make sense of their environment, among them the olfactory and gustatory sense of vertebrates and arthropods. Both senses use large repertoires of receptors to achieve perception of complex chemosensory stimuli. High evolutionary dynamics of some olfactory and gustatory receptor gene families result in considerable variance of chemosensory perception between species. Interestingly, both ora/v1r genes and the closely related t2r genes constitute small and rather conserved families in teleost fish, but show rapid evolution and large species differences in tetrapods. To understand this transition, chemosensory gene repertoires of earlier diverging members of the tetrapod lineage, i.e. lobe-finned fish such as Latimeria would be of high interest. Results We report here the complete T2R repertoire of Latimeria chalumnae, using thorough data mining and extensive phylogenetic analysis. Eighty t2r genes were identified, by far the largest family reported for any species so far. The genomic neighborhood of t2r genes is enriched in repeat elements, which may have facilitated the extensive gene duplication events resulting in such a large family. Examination of non-synonymous vs. synonymous substitution rates (dN/dS) suggests pronounced positive Darwinian selection in Latimeria T2Rs, conceivably ensuring efficient neo-functionalization of newly born t2r genes. Notably, both traits, positive selection and enrichment of repeat elements in the genomic neighborhood, are absent in the twenty v1r genes of Latimeria. Sequence divergence in Latimeria T2Rs and V1Rs is high, reminescent of the corresponding teleost families. Some conserved sequence motifs of Latimeria T2Rs and V1Rs are shared with the respective teleost but not tetrapod genes, consistent with a potential role of such motifs in detection of aquatic chemosensory stimuli. Conclusions The singularly large T2R repertoire of Latimeria may have been generated by facilitating local gene duplication via increased density of repeat elements, and efficient neofunctionalization via positive Darwinian selection. The high evolutionary dynamics of tetrapod t2r gene families precedes the emergence of tetrapods, i.e. the water-to-land transition, and thus constitutes a basal feature of the lobe-finned lineage of vertebrates. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-650) contains supplementary material, which is available to authorized users.
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94
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Prevedel R, Yoon YG, Hoffmann M, Pak N, Wetzstein G, Kato S, Schrödel T, Raskar R, Zimmer M, Boyden ES, Vaziri A. Simultaneous whole-animal 3D imaging of neuronal activity using light-field microscopy. Nat Methods 2014; 11:727-730. [PMID: 24836920 PMCID: PMC4100252 DOI: 10.1038/nmeth.2964] [Citation(s) in RCA: 382] [Impact Index Per Article: 38.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Accepted: 04/22/2014] [Indexed: 12/20/2022]
Abstract
High-speed, large-scale three-dimensional (3D) imaging of neuronal activity poses a major challenge in neuroscience. Here we demonstrate simultaneous functional imaging of neuronal activity at single-neuron resolution in an entire Caenorhabditis elegans and in larval zebrafish brain. Our technique captures the dynamics of spiking neurons in volumes of ∼700 μm × 700 μm × 200 μm at 20 Hz. Its simplicity makes it an attractive tool for high-speed volumetric calcium imaging.
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Affiliation(s)
- Robert Prevedel
- Research Institute of Molecular Pathology, Vienna, Austria
- Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
- Research Platform Quantum Phenomena & Nanoscale Biological Systems (QuNaBioS), University of Vienna, Austria
| | - Young-Gyu Yoon
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
- MIT Media Lab, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
| | - Maximilian Hoffmann
- Research Institute of Molecular Pathology, Vienna, Austria
- Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
- Research Platform Quantum Phenomena & Nanoscale Biological Systems (QuNaBioS), University of Vienna, Austria
| | - Nikita Pak
- MIT Media Lab, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
- Department of Mechanical Engineering, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
| | - Gordon Wetzstein
- MIT Media Lab, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
| | - Saul Kato
- Research Institute of Molecular Pathology, Vienna, Austria
| | - Tina Schrödel
- Research Institute of Molecular Pathology, Vienna, Austria
| | - Ramesh Raskar
- MIT Media Lab, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
| | - Manuel Zimmer
- Research Institute of Molecular Pathology, Vienna, Austria
| | - Edward S Boyden
- MIT Media Lab, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
- Department of Biological Engineering, Massachusetts Institute of Technology(MIT), Cambridge, MA, USA
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
- McGovern Institute, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
| | - Alipasha Vaziri
- Research Institute of Molecular Pathology, Vienna, Austria
- Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
- Research Platform Quantum Phenomena & Nanoscale Biological Systems (QuNaBioS), University of Vienna, Austria
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95
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Friedrich RW, Wiechert MT. Neuronal circuits and computations: pattern decorrelation in the olfactory bulb. FEBS Lett 2014; 588:2504-13. [PMID: 24911205 DOI: 10.1016/j.febslet.2014.05.055] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Revised: 05/28/2014] [Accepted: 05/29/2014] [Indexed: 11/15/2022]
Abstract
Neuronal circuits in the olfactory bulb transform odor-evoked activity patterns across the input channels, the olfactory glomeruli, into distributed activity patterns across the output neurons, the mitral cells. One computation associated with this transformation is a decorrelation of activity patterns representing similar odors. Such a decorrelation has various benefits for the classification and storage of information by associative networks in higher brain areas. Experimental results from adult zebrafish show that pattern decorrelation involves a redistribution of activity across the population of mitral cells. These observations imply that pattern decorrelation cannot be explained by a global scaling mechanism but that it depends on interactions between distinct subsets of neurons in the network. This article reviews insights into the network mechanism underlying pattern decorrelation and discusses recent results that link pattern decorrelation in the olfactory bulb to odor discrimination behavior.
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Affiliation(s)
- Rainer W Friedrich
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland; University of Basel, 4003 Basel, Switzerland.
| | - Martin T Wiechert
- Laboratory for Perception and Memory, Institut Pasteur, 25 rue du Docteur Roux, 75724 Paris, France; CNRS UMR3571, 25 rue du Docteur Roux, 75724 Paris, France
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96
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Abstract
How is sensory information represented in the brain? A long-standing debate in neural coding is whether and how timing of spikes conveys information to downstream neurons. Although we know that neurons in the olfactory bulb (OB) exhibit rich temporal dynamics, the functional relevance of temporal coding remains hotly debated. Recent recording experiments in awake behaving animals have elucidated highly organized temporal structures of activity in the OB. In addition, the analysis of neural circuits in the piriform cortex (PC) demonstrated the importance of not only OB afferent inputs but also intrinsic PC neural circuits in shaping odor responses. Furthermore, new experiments involving stimulation of the OB with specific temporal patterns allowed for testing the relevance of temporal codes. Together, these studies suggest that the relative timing of neuronal activity in the OB conveys odor information and that neural circuits in the PC possess various mechanisms to decode temporal patterns of OB input.
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Affiliation(s)
- Naoshige Uchida
- Department of Molecular and Cellular Biology, Center for Brain Science, Harvard University, Cambridge, Massachusetts 02138;
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97
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Behrens M, Frank O, Rawel H, Ahuja G, Potting C, Hofmann T, Meyerhof W, Korsching S. ORA1, a zebrafish olfactory receptor ancestral to all mammalian V1R genes, recognizes 4-hydroxyphenylacetic acid, a putative reproductive pheromone. J Biol Chem 2014; 289:19778-88. [PMID: 24831010 DOI: 10.1074/jbc.m114.573162] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The teleost v1r-related ora genes are a small, highly conserved olfactory receptor gene family of only six genes, whose direct orthologues can be identified in lineages as far as that of cartilaginous fish. However, no ligands for fish olfactory receptor class A related genes (ORA) had been uncovered so far. Here we have deorphanized the ORA1 receptor using heterologous expression and calcium imaging. We report that zebrafish ORA1 recognizes with high specificity and sensitivity 4-hydroxyphenylacetic acid. The carboxyl group of this compound is required in a particular distance from the aromatic ring, whereas the hydroxyl group in the para-position is not essential, but strongly enhances the binding efficacy. Low concentrations of 4-hydroxyphenylacetic acid elicit increases in oviposition frequency in zebrafish mating pairs. This effect is abolished by naris closure. We hypothesize that 4-hydroxyphenylacetic acid might function as a pheromone for reproductive behavior in zebrafish. ORA1 is ancestral to mammalian V1Rs, and its putative function as pheromone receptor is reminiscent of the role of several mammalian V1Rs as pheromone receptors.
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Affiliation(s)
- Maik Behrens
- From the Department of Molecular Genetics, German Institute of Human Nutrition Potsdam-Rehbruecke, Arthur-Scheunert-Allee 114-116, 14558 Nuthetal
| | - Oliver Frank
- the Chair of Food Chemistry and Molecular Sensory Science, Technische Universität München, Lise-Meitner-Strasse 34, 85354 Freising
| | - Harshadrai Rawel
- the Institute of Nutrition Science, University of Potsdam, Arthur-Scheunert-Allee 114-116, 14558 Nuthetal, and
| | - Gaurav Ahuja
- the Institute of Genetics, University at Cologne, Zülpicher Str. 47A, 50674 Cologne, Germany
| | - Christoph Potting
- the Institute of Genetics, University at Cologne, Zülpicher Str. 47A, 50674 Cologne, Germany
| | - Thomas Hofmann
- the Chair of Food Chemistry and Molecular Sensory Science, Technische Universität München, Lise-Meitner-Strasse 34, 85354 Freising
| | - Wolfgang Meyerhof
- From the Department of Molecular Genetics, German Institute of Human Nutrition Potsdam-Rehbruecke, Arthur-Scheunert-Allee 114-116, 14558 Nuthetal
| | - Sigrun Korsching
- the Institute of Genetics, University at Cologne, Zülpicher Str. 47A, 50674 Cologne, Germany
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98
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Olfactory projectome in the zebrafish forebrain revealed by genetic single-neuron labelling. Nat Commun 2014; 5:3639. [DOI: 10.1038/ncomms4639] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Accepted: 03/12/2014] [Indexed: 11/08/2022] Open
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99
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Friedrich RW. Calcium imaging in the intact olfactory system of zebrafish and mouse. Cold Spring Harb Protoc 2014; 2014:310-6. [PMID: 24591696 DOI: 10.1101/pdb.prot081166] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Odors are first detected by olfactory sensory neurons (OSNs) and evoke stimulus-specific patterns of activation across the input channels of the olfactory bulb (OB), the glomeruli. The output of the OB consists of spatiotemporal activity patterns across mitral/tufted cells that are conveyed to multiple pallial and subpallial target areas. In the main olfactory system of vertebrates, as well as in the olfactory system of insects, odor information is encoded by distributed patterns of activity across a large number of glomeruli or neurons. Ca(2+) imaging has therefore become an important approach used to analyse the encoding and processing of olfactory information by populations of glomeruli or neurons. Experiments in the intact olfactory system are important to maintain the integrity of the system, to analyse activity patterns evoked by natural odors, and to examine the influence of active sampling strategies, such as sniffing in mammals. This protocol focuses on how to visualize glomerular Ca(2+) signals after loading a dextran-coupled Ca(2+) indicator into OSNs. Separate procedures are described for zebrafish and mice.
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100
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Fujiwara T, Kazawa T, Haupt SS, Kanzaki R. Postsynaptic odorant concentration dependent inhibition controls temporal properties of spike responses of projection neurons in the moth antennal lobe. PLoS One 2014; 9:e89132. [PMID: 24586546 PMCID: PMC3929629 DOI: 10.1371/journal.pone.0089132] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2013] [Accepted: 01/21/2014] [Indexed: 11/24/2022] Open
Abstract
Although odorant concentration-response characteristics of olfactory neurons have been widely investigated in a variety of animal species, the effect of odorant concentration on neural processing at circuit level is still poorly understood. Using calcium imaging in the silkmoth (Bombyx mori) pheromone processing circuit of the antennal lobe (AL), we studied the effect of odorant concentration on second-order projection neuron (PN) responses. While PN calcium responses of dendrites showed monotonic increases with odorant concentration, calcium responses of somata showed decreased responses at higher odorant concentrations due to postsynaptic inhibition. Simultaneous calcium imaging and electrophysiology revealed that calcium responses of PN somata but not dendrites reflect spiking activity. Inhibition shortened spike response duration rather than decreasing peak instantaneous spike frequency (ISF). Local interneurons (LNs) that were specifically activated at high odorant concentrations at which PN responses were suppressed are the putative source of inhibition. Our results imply the existence of an intraglomerular mechanism that preserves time resolution in olfactory processing over a wide odorant concentration range.
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Affiliation(s)
- Terufumi Fujiwara
- Graduate School of Information Science and Technology, The University of Tokyo, Tokyo, Japan
| | - Tomoki Kazawa
- Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan
| | - Stephan Shuichi Haupt
- Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan
| | - Ryohei Kanzaki
- Graduate School of Information Science and Technology, The University of Tokyo, Tokyo, Japan
- Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan
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