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Fulton KA, Zimmerman D, Samuel A, Vogt K, Datta SR. Common principles for odour coding across vertebrates and invertebrates. Nat Rev Neurosci 2024; 25:453-472. [PMID: 38806946 DOI: 10.1038/s41583-024-00822-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/30/2024] [Indexed: 05/30/2024]
Abstract
The olfactory system is an ideal and tractable system for exploring how the brain transforms sensory inputs into behaviour. The basic tasks of any olfactory system include odour detection, discrimination and categorization. The challenge for the olfactory system is to transform the high-dimensional space of olfactory stimuli into the much smaller space of perceived objects and valence that endows odours with meaning. Our current understanding of how neural circuits address this challenge has come primarily from observations of the mechanisms of the brain for processing other sensory modalities, such as vision and hearing, in which optimized deep hierarchical circuits are used to extract sensory features that vary along continuous physical dimensions. The olfactory system, by contrast, contends with an ill-defined, high-dimensional stimulus space and discrete stimuli using a circuit architecture that is shallow and parallelized. Here, we present recent observations in vertebrate and invertebrate systems that relate the statistical structure and state-dependent modulation of olfactory codes to mechanisms of perception and odour-guided behaviour.
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Affiliation(s)
- Kara A Fulton
- Department of Neuroscience, Harvard Medical School, Boston, MA, USA
| | - David Zimmerman
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - Aravi Samuel
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - Katrin Vogt
- Department of Physics, Harvard University, Cambridge, MA, USA.
- Department of Biology, University of Konstanz, Konstanz, Germany.
- Centre for the Advanced Study of Collective Behaviour, University of Konstanz, Konstanz, Germany.
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2
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Matukhno AE, Petrushan MV, Kiroy VN, Arsenyev FV, Lysenko LV. The method for assessment of local permutations in the glomerular patterns of the rat olfactory bulb by aligning interindividual odor maps. J Comput Neurosci 2023; 51:433-444. [PMID: 37624481 DOI: 10.1007/s10827-023-00858-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 07/06/2023] [Accepted: 07/31/2023] [Indexed: 08/26/2023]
Abstract
The comparison of odor functional maps in rodents demonstrates a high degree of inter-individual variability in glomerular activity patterns. There are substantial methodological difficulties in the interindividual assessment of local permutations in the glomerular patterns, since the position of anatomical extracranial landmarks, as well as the size, shape and angular orientation of olfactory bulbs can vary significantly. A new method for defining anatomical coordinates of active glomeruli in the rat olfactory bulb has been developed. The method compares the interindividual odor functional maps and calculates probabilistic maps of glomerular activity with adjustment. This adjustment involves rotation, scaling and shift of the functional map relative to its expected position in probabilistic map, computed according to the anatomical coordinates. The calculation of the probabilistic map of the odorant-specific response compensates for potential anatoamical errors due to individual variability in olfactory bulb dimensions and angular orientation. We show its efficiency on real data from a large animal sample recorded by two-photon calcium imaging in dorsal surface of the rat olfactory bulb. The proposed method with probabilistic map calculation enables the spatial consistency of the effects of individual odorants in different rats to be assessed and allow stereotypical positions of odor-specific clusters in the glomerular layer of the olfactory bulb to be identified.
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Affiliation(s)
- Aleksey E Matukhno
- Research Center for Neurotechnology, Southern Federal University, Rostov-on-Don, 344090, Russia.
| | - Mikhail V Petrushan
- Research Center for Neurotechnology, Southern Federal University, Rostov-on-Don, 344090, Russia
| | - Valery N Kiroy
- Research Center for Neurotechnology, Southern Federal University, Rostov-on-Don, 344090, Russia
| | | | - Larisa V Lysenko
- Research Center for Neurotechnology, Southern Federal University, Rostov-on-Don, 344090, Russia
- Department of Physics, Southern Federal University, Rostov-on-Don, 344090, Russia
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3
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Huang JS, Kunkhyen T, Rangel AN, Brechbill TR, Gregory JD, Winson-Bushby ED, Liu B, Avon JT, Muggleton RJ, Cheetham CEJ. Immature olfactory sensory neurons provide behaviourally relevant sensory input to the olfactory bulb. Nat Commun 2022; 13:6194. [PMID: 36261441 PMCID: PMC9582225 DOI: 10.1038/s41467-022-33967-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 10/07/2022] [Indexed: 01/12/2023] Open
Abstract
Postnatal neurogenesis provides an opportunity to understand how newborn neurons integrate into circuits to restore function. Newborn olfactory sensory neurons (OSNs) wire into highly organized olfactory bulb (OB) circuits throughout life, enabling lifelong plasticity and regeneration. Immature OSNs form functional synapses capable of evoking firing in OB projection neurons but what contribution, if any, they make to odor processing is unknown. Here, we show that immature OSNs provide odor input to the mouse OB, where they form monosynaptic connections with excitatory neurons. Importantly, immature OSNs respond as selectively to odorants as mature OSNs and exhibit graded responses across a wider range of odorant concentrations than mature OSNs, suggesting that immature and mature OSNs provide distinct odor input streams. Furthermore, mice can successfully perform odor detection and discrimination tasks using sensory input from immature OSNs alone. Together, our findings suggest that immature OSNs play a previously unappreciated role in olfactory-guided behavior.
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Affiliation(s)
- Jane S Huang
- Department of Neurobiology, University of Pittsburgh, 200 Lothrop St, Pittsburgh, PA, 15232, USA
| | - Tenzin Kunkhyen
- Department of Neurobiology, University of Pittsburgh, 200 Lothrop St, Pittsburgh, PA, 15232, USA
| | - Alexander N Rangel
- Department of Neurobiology, University of Pittsburgh, 200 Lothrop St, Pittsburgh, PA, 15232, USA
| | - Taryn R Brechbill
- Department of Neurobiology, University of Pittsburgh, 200 Lothrop St, Pittsburgh, PA, 15232, USA
| | - Jordan D Gregory
- Department of Neurobiology, University of Pittsburgh, 200 Lothrop St, Pittsburgh, PA, 15232, USA
| | - Emily D Winson-Bushby
- Department of Neurobiology, University of Pittsburgh, 200 Lothrop St, Pittsburgh, PA, 15232, USA
| | - Beichen Liu
- Department of Neurobiology, University of Pittsburgh, 200 Lothrop St, Pittsburgh, PA, 15232, USA
- Department of Biological Sciences, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA, 15213, USA
| | - Jonathan T Avon
- Department of Neurobiology, University of Pittsburgh, 200 Lothrop St, Pittsburgh, PA, 15232, USA
| | - Ryan J Muggleton
- Department of Neurobiology, University of Pittsburgh, 200 Lothrop St, Pittsburgh, PA, 15232, USA
- Department of Biological Sciences, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA, 15213, USA
| | - Claire E J Cheetham
- Department of Neurobiology, University of Pittsburgh, 200 Lothrop St, Pittsburgh, PA, 15232, USA.
- Department of Biological Sciences, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA, 15213, USA.
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4
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Patel R, Hallem EA. Olfaction: One receptor drives opposite behaviors. Curr Biol 2022; 32:R93-R96. [PMID: 35077699 DOI: 10.1016/j.cub.2021.12.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Many odorants are attractive at low concentrations but repulsive at higher concentrations. A new study demonstrates that, in Caenorhabditis elegans, a single odorant receptor acts in two different neuron pairs to mediate both attractive and repulsive responses to an odorant.
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Affiliation(s)
- Ruhi Patel
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Elissa A Hallem
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA.
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5
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Contreras-Hernández E, Chávez D, Hernández E, Rudomin P. Discrete field potentials produced by coherent activation of spinal dorsal horn neurons. Exp Brain Res 2022; 240:665-686. [PMID: 35001174 DOI: 10.1007/s00221-021-06286-3] [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: 08/19/2021] [Accepted: 12/03/2021] [Indexed: 11/28/2022]
Abstract
In addition to the action potentials generated by the ongoing activation of single dorsal horn neurons in the anesthetized cat, we often recorded small negative field potentials with a fast-rising phase and a slow decay (dIFPs). These potentials could be separated in different classes, each with a specific and rather constant shape and amplitude. They were largest in spinal laminae III-V and gradually faded at deeper locations, without showing the polarity reversal displayed at these depths by the focal potentials produced by stimulation of muscle and cutaneous afferents. We propose that the dIFPs are postsynaptic field potentials generated by strongly coupled sets of dorsal horn neurons displaying a spatial orientation that generates closed field potentials in response to stimulation of high-threshold cutaneous and muscle afferents. These neuronal sets could form part of the spinal inhibitory circuitry that mediates presynaptic inhibition and Ib non-reciprocal postsynaptic inhibition and could be involved in the sensory-motor transformations activated by stimulation of high-threshold cutaneous afferents.
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Affiliation(s)
- Enrique Contreras-Hernández
- Department of Physiology, Biophysics and Neurosciences, Center for Research and Advanced Studies, National Polytechnic Institute, Ciudad de México, México
| | - Diógenes Chávez
- Department of Physiology, Biophysics and Neurosciences, Center for Research and Advanced Studies, National Polytechnic Institute, Ciudad de México, México
| | - Edson Hernández
- Department of Physiology, Biophysics and Neurosciences, Center for Research and Advanced Studies, National Polytechnic Institute, Ciudad de México, México
| | - Pablo Rudomin
- Department of Physiology, Biophysics and Neurosciences, Center for Research and Advanced Studies, National Polytechnic Institute, Ciudad de México, México. .,El Colegio Nacional, Ciudad de México, México.
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6
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Deconstructing the mouse olfactory percept through an ethological atlas. Curr Biol 2021; 31:2809-2818.e3. [PMID: 33957076 DOI: 10.1016/j.cub.2021.04.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 03/09/2021] [Accepted: 04/09/2021] [Indexed: 10/21/2022]
Abstract
Odor perception in non-humans is poorly understood. Here, we generated the most comprehensive mouse olfactory ethological atlas to date, consisting of behavioral responses to a diverse panel of 73 odorants, including 12 at multiple concentrations. These data revealed that mouse behavior is incredibly diverse and changes in response to odorant identity and concentration. Using only behavioral responses observed in other mice, we could predict which of two odorants was presented to a held-out mouse 82% of the time. Considering all 73 possible odorants, we could uniquely identify the target odorant from behavior on the first try 20% of the time and 46% within five attempts. Although mouse behavior is difficult to predict from human perception, they share three fundamental properties: first, odor valence parameters explained the highest variance of olfactory perception. Second, physicochemical properties of odorants can be used to predict the olfactory percept. Third, odorant concentration quantitatively and qualitatively impacts olfactory perception. These results increase our understanding of mouse olfactory behavior and how it compares to human odor perception and provide a template for future comparative studies of olfactory percepts among species.
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Imamura F, Ito A, LaFever BJ. Subpopulations of Projection Neurons in the Olfactory Bulb. Front Neural Circuits 2020; 14:561822. [PMID: 32982699 PMCID: PMC7485133 DOI: 10.3389/fncir.2020.561822] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 08/12/2020] [Indexed: 12/17/2022] Open
Abstract
Generation of neuronal diversity is a biological strategy widely used in the brain to process complex information. The olfactory bulb is the first relay station of olfactory information in the vertebrate central nervous system. In the olfactory bulb, axons of the olfactory sensory neurons form synapses with dendrites of projection neurons that transmit the olfactory information to the olfactory cortex. Historically, the olfactory bulb projection neurons have been classified into two populations, mitral cells and tufted cells. The somata of these cells are distinctly segregated within the layers of the olfactory bulb; the mitral cells are located in the mitral cell layer while the tufted cells are found in the external plexiform layer. Although mitral and tufted cells share many morphological, biophysical, and molecular characteristics, they differ in soma size, projection patterns of their dendrites and axons, and odor responses. In addition, tufted cells are further subclassified based on the relative depth of their somata location in the external plexiform layer. Evidence suggests that different types of tufted cells have distinct cellular properties and play different roles in olfactory information processing. Therefore, mitral and different types of tufted cells are considered as starting points for parallel pathways of olfactory information processing in the brain. Moreover, recent studies suggest that mitral cells also consist of heterogeneous subpopulations with different cellular properties despite the fact that the mitral cell layer is a single-cell layer. In this review, we first compare the morphology of projection neurons in the olfactory bulb of different vertebrate species. Next, we explore the similarities and differences among subpopulations of projection neurons in the rodent olfactory bulb. We also discuss the timing of neurogenesis as a factor for the generation of projection neuron heterogeneity in the olfactory bulb. Knowledge about the subpopulations of olfactory bulb projection neurons will contribute to a better understanding of the complex olfactory information processing in higher brain regions.
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Affiliation(s)
- Fumiaki Imamura
- Department of Pharmacology, Penn State College of Medicine, Hershey, PA, United States
| | - Ayako Ito
- Department of Pharmacology, Penn State College of Medicine, Hershey, PA, United States
| | - Brandon J LaFever
- Department of Pharmacology, Penn State College of Medicine, Hershey, PA, United States
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8
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Direct Comparison of Odor Responses of Homologous Glomeruli in the Medial and Lateral Maps of the Mouse Olfactory Bulb. eNeuro 2020; 7:ENEURO.0449-19.2020. [PMID: 31974110 PMCID: PMC7073388 DOI: 10.1523/eneuro.0449-19.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 12/31/2019] [Accepted: 01/10/2020] [Indexed: 11/29/2022] Open
Abstract
Olfactory sensory neurons (OSNs) expressing same-type odorant receptors typically project to a pair of glomeruli in the medial and lateral sides of the olfactory bulbs (OBs) in rodents. This multiple glomerular representation of homologous inputs is considered to have more important functional roles for odor information processing than the redundant backup system. However, a consensus idea is lacking and this hinders interpretation of the phenomenon. In addition, the shared and unique odorant response properties of the homologous glomeruli remain unclear because the majority of medial glomeruli are hidden in the septal OB, and thus it is difficult to directly compare them. OSNs, which express trace amine-associated odorant receptors (TAARs), were recently identified that project to a pair of glomeruli uniquely located in the dorsal OB. In this study, we measured the odorant-induced calcium responses of homologous pairs of TAAR glomeruli simultaneously in anesthetized mice and directly compared their response patterns. We found that they exhibited similar temporal response patterns and could not find differences in onset latency, rise time, decay time, or response amplitude. However, the medial glomeruli had significantly larger respiration-locked calcium fluctuations than the lateral glomeruli. This trend was observed with/without odorant stimulation in postsynaptic neurons of GABAergic, dopaminergic, and mitral/tufted cells, but not in presynaptic olfactory sensory axon terminals. This indicates that, at least in these TAAR glomeruli, the medial rather than the lateral OB map enhances the respiration-locked rhythm and transfers this information to higher brain centers.
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Sanganahalli BG, Baker KL, Thompson GJ, Herman P, Shepherd GM, Verhagen JV, Hyder F. Orthonasal versus retronasal glomerular activity in rat olfactory bulb by fMRI. Neuroimage 2020; 212:116664. [PMID: 32087375 DOI: 10.1016/j.neuroimage.2020.116664] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 01/22/2020] [Accepted: 02/16/2020] [Indexed: 02/05/2023] Open
Abstract
Odorants can reach olfactory receptor neurons (ORNs) by two routes: orthonasally, when volatiles enter the nasal cavity during inhalation/sniffing, and retronasally, when food volatiles released in the mouth pass into the nasal cavity during exhalation/eating. Previous work in humans has shown that both delivery routes of the same odorant can evoke distinct perceptions and patterns of neural responses in the brain. Each delivery route is known to influence specific responses across the dorsal region of the glomerular sheet in the olfactory bulb (OB), but spatial distributions across the entire glomerular sheet throughout the whole OB remain largely unexplored. We used functional MRI (fMRI) to measure and compare activations across the entire glomerular sheet in rat OB resulting from both orthonasal and retronasal stimulations of the same odors. We observed reproducible fMRI activation maps of the whole OB during both orthonasal and retronasal stimuli. However, retronasal stimuli required double the orthonasal odor concentration for similar response amplitudes. Regardless, both the magnitude and spatial extent of activity were larger during orthonasal versus retronasal stimuli for the same odor. Orthonasal and retronasal response patterns show overlap as well as some route-specific dominance. Orthonasal maps were dominant in dorsal-medial regions, whereas retronasal maps were dominant in caudal and lateral regions. These different whole OB encodings likely underlie differences in odor perception between these biologically important routes for odorants among mammals. These results establish the relationships between orthonasal and retronasal odor representations in the rat 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.
| | - Keeley L Baker
- Department of Neuroscience, Yale University, New Haven, CT, USA; The John B. Pierce Laboratory, New Haven, CT, USA
| | - Garth J Thompson
- Magnetic Resonance Research Center (MRRC), Yale University, New Haven, CT, USA; iHuman Institute, ShanghaiTech University, Shanghai, 201210, China
| | - 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
| | | | - Justus V Verhagen
- Department of Neuroscience, 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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10
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Baker KL, Vasan G, Gumaste A, Pieribone VA, Verhagen JV. Spatiotemporal dynamics of odor responses in the lateral and dorsal olfactory bulb. PLoS Biol 2019; 17:e3000409. [PMID: 31532763 PMCID: PMC6768483 DOI: 10.1371/journal.pbio.3000409] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 09/30/2019] [Accepted: 08/22/2019] [Indexed: 01/04/2023] Open
Abstract
The mammalian olfactory bulb (OB) plays an essential role in odor processing during the perception of smell. Optical imaging of the OB has proven to be a key tool in elucidating the spatial odor mapping and temporal dynamics that underlie higher-order odor processing. Much is known about the activation of olfactory sensory neuron (OSN) glomerular responses in the dorsal olfactory bulb (dOB) during odor presentation. However, the dorsal bulb provides access to only approximately 25% of all glomeruli, and little is known about how the lateral bulb functions during this critical process. Here, we report, for the first time, simultaneous measurements of OSN glomerular activity from both the dOB and the lateral olfactory bulb (lOB), thus describing odor-specific spatial mapping and the temporal dynamics of olfactory input to both the dorsal and lateral bulb. Odor responses in the lateral bulb tended to be most prominent in the dorso-lateral (D-L) region. Lateral glomeruli became active in a dorso-ventral (D-V) sequence upon odor inhalation, unlike the anterio-posterior (A-P) activity wave typical of the dorsal glomeruli. Across the entire D-L bulb, the spatial organization of these dynamics can be explained neither by the purely mechanosensitive dynamics (to breathing clean air) nor by the response amplitudes across glomeruli. Instead, these dynamics can be explained by a combination of zonal receptor distributions, associated OB projections, and air flow paths across the epithelium upon inhalation. Remarkably, we also found that a subset of OSN glomeruli in the lOB was highly sensitive to extranasal air pressure changes, a response type that has not been reported in dorsal glomeruli. The mammalian olfactory bulb plays an essential role in odor processing during the perception of smell, but most studies have focused on the dorsal olfactory bulb, which contains only a quarter of all glomeruli. In this study, imaging of the lateral olfactory bulb reveals new properties in smell processing.
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Affiliation(s)
- Keeley L. Baker
- The John B. Pierce Laboratory, New Haven, Connecticut, United States of America
- Department of Neuroscience, Yale School of Medicine, New Haven, Connecticut, United States of America
| | - Ganesh Vasan
- The John B. Pierce Laboratory, New Haven, Connecticut, United States of America
- Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, Connecticut, United States of America
| | - Ankita Gumaste
- The John B. Pierce Laboratory, New Haven, Connecticut, United States of America
- Department of Neuroscience, Yale School of Medicine, New Haven, Connecticut, United States of America
| | - Vincent A. Pieribone
- The John B. Pierce Laboratory, New Haven, Connecticut, United States of America
- Department of Neuroscience, Yale School of Medicine, New Haven, Connecticut, United States of America
- Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, Connecticut, United States of America
| | - Justus V. Verhagen
- The John B. Pierce Laboratory, New Haven, Connecticut, United States of America
- Department of Neuroscience, Yale School of Medicine, New Haven, Connecticut, United States of America
- * E-mail:
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11
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Target specific functions of EPL interneurons in olfactory circuits. Nat Commun 2019; 10:3369. [PMID: 31358754 PMCID: PMC6662826 DOI: 10.1038/s41467-019-11354-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 06/27/2019] [Indexed: 12/02/2022] Open
Abstract
Inhibitory interneurons are integral to sensory processing, yet revealing their cell type-specific roles in sensory circuits remains an ongoing focus. To Investigate the mouse olfactory system, we selectively remove GABAergic transmission from a subset of olfactory bulb interneurons, EPL interneurons (EPL-INs), and assay odor responses from their downstream synaptic partners — tufted cells and mitral cells. Using a combination of in vivo electrophysiological and imaging analyses, we find that inactivating this single node of inhibition leads to differential effects in magnitude, reliability, tuning width, and temporal dynamics between the two principal neurons. Furthermore, tufted and not mitral cell responses to odor mixtures become more linearly predictable without EPL-IN inhibition. Our data suggest that olfactory bulb interneurons, through exerting distinct inhibitory functions onto their different synaptic partners, play a significant role in the processing of odor information. The precise cell-type specific role of inhibitory interneurons in regulating sensory responses in the olfactory bulb is not known. Here, the authors report that removing GABAergic inhibition from one layer differentially affects response dynamics of the two main output cell types and changes odor mixture processing.
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12
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Feng S, Suh JH, Gmitter FG, Wang Y. Differentiation between Flavors of Sweet Orange ( Citrus sinensis) and Mandarin ( Citrus reticulata). JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:203-211. [PMID: 0 DOI: 10.1021/acs.jafc.7b04968] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Affiliation(s)
- Shi Feng
- Department
of Food Science and Human Nutrition, University of Florida, 572 Newell
Drive, Gainesville, Florida 32611, United States
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Indistinguishable odour enantiomers: Differences between peripheral and central-nervous electrophysiological responses. Sci Rep 2017; 7:8978. [PMID: 28827647 PMCID: PMC5566401 DOI: 10.1038/s41598-017-09594-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 07/21/2017] [Indexed: 11/09/2022] Open
Abstract
The ability of humans to discriminate enantiomeric odour pairs is substance -specific. Current literature suggests that psychophysical discrimination of odour enantiomers mainly depends on the peripheral processing at the level of the olfactory sensory neurons (OSN). To study the influence of central processing in discrimination, we investigated differences in the electrophysiological responses to psychophysically indistinguishable (+)- and (-)- rose oxide enantiomers at peripheral and central-nervous levels in humans. We recorded the electro-olfactogram (EOG) from the olfactory epithelium and the EEG-derived olfactory event-related potentials (OERP). Results from a psychophysical three alternative forced choice test indicated indistinguishability of the two odour enantiomers. In a total of 19 young participants EOG could be recorded in 74 and OERP in 95% of subjects. Significantly different EOG amplitudes and latencies were recorded in response to the 2 stimuli. However, no such differences in amplitude or latency emerged for the OERP. In conclusion, although the pair of enantiomer could be discriminated at a peripheral level this did not lead to a central-nervous/cognitive differentiation of the two stimuli.
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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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15
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Milardi D, Cacciola A, Calamuneri A, Ghilardi MF, Caminiti F, Cascio F, Andronaco V, Anastasi G, Mormina E, Arrigo A, Bruschetta D, Quartarone A. The Olfactory System Revealed: Non-Invasive Mapping by using Constrained Spherical Deconvolution Tractography in Healthy Humans. Front Neuroanat 2017; 11:32. [PMID: 28443000 PMCID: PMC5385345 DOI: 10.3389/fnana.2017.00032] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2017] [Accepted: 03/28/2017] [Indexed: 11/27/2022] Open
Abstract
Although the olfactory sense has always been considered with less interest than the visual, auditive or somatic senses, it does plays a major role in our ordinary life, with important implication in dangerous situations or in social and emotional behaviors. Traditional Diffusion Tensor signal model and related tractography have been used in the past years to reconstruct the cranial nerves, including the olfactory nerve (ON). However, no supplementary information with regard to the pathways of the olfactory network have been provided. Here, by using the more advanced Constrained Spherical Deconvolution (CSD) diffusion model, we show for the first time in vivo and non-invasively that, in healthy humans, the olfactory system has a widely distributed anatomical network to several cortical regions as well as to many subcortical structures. Although the present study focuses on an healthy sample size, a similar approach could be applied in the near future to gain important insights with regard to the early involvement of olfaction in several neurodegenerative disorders.
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Affiliation(s)
- Demetrio Milardi
- Centro Neurolesi Bonino Pulejo (IRCCS)Messina, Italy.,Department of Biomedical, Dental Sciences and Morphological and Functional Images, University of MessinaMessina, Italy
| | | | - Alessandro Calamuneri
- Department of Biomedical, Dental Sciences and Morphological and Functional Images, University of MessinaMessina, Italy
| | - Maria F Ghilardi
- Sophie Davis School for Biomedical Education, City College New York (CCNY), The City University of New York (CUNY)New York, NY, USA.,The Fresco Institute for Parkinson's and Movement Disorders, NYU Langone Medical Center, New York UniversityNew York, NY, USA
| | | | - Filippo Cascio
- Department of Otorhinolaryngology, Papardo HospitalMessina, Italy
| | | | - Giuseppe Anastasi
- Department of Biomedical, Dental Sciences and Morphological and Functional Images, University of MessinaMessina, Italy
| | - Enricomaria Mormina
- Department of Biomedical, Dental Sciences and Morphological and Functional Images, University of MessinaMessina, Italy
| | - Alessandro Arrigo
- Department of Biomedical, Dental Sciences and Morphological and Functional Images, University of MessinaMessina, Italy
| | - Daniele Bruschetta
- Centro Neurolesi Bonino Pulejo (IRCCS)Messina, Italy.,Department of Biomedical, Dental Sciences and Morphological and Functional Images, University of MessinaMessina, Italy
| | - Angelo Quartarone
- Centro Neurolesi Bonino Pulejo (IRCCS)Messina, Italy.,Department of Biomedical, Dental Sciences and Morphological and Functional Images, University of MessinaMessina, Italy
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16
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17
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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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18
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Affiliation(s)
- Anne Tromelin
- CNRS; UMR6265 Centre des Sciences du Goût et de l'Alimentation; F-21000 Dijon France
- INRA; UMR1324 Centre des Sciences du Goût et de l'Alimentation; F-21000 Dijon France
- Université de Bourgogne; UMR Centre des Sciences du Goût et de l'Alimentation; F-21000 Dijon France
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19
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Nunez-Parra A, Li A, Restrepo D. Coding odor identity and odor value in awake rodents. PROGRESS IN BRAIN RESEARCH 2015; 208:205-22. [PMID: 24767484 DOI: 10.1016/b978-0-444-63350-7.00008-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
In the last decade, drastic changes in the understanding of the role of the olfactory bulb and piriform cortex in odor detection have taken place through awake behaving recording in rodents. It is clear that odor responses in mitral and granule cells are strikingly different in the olfactory bulb of anesthetized versus awake animals. In addition, sniff recording has evidenced that mitral cell responses to odors during the sniff can convey information on the odor identity and sniff phase. Moreover, we review studies that show that the mitral cell conveys information on not only odor identity but also whether the odor is rewarded or not (odor value). Finally, we discuss how the substantial increase in awake behaving recording raises questions for future studies.
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Affiliation(s)
- Alexia Nunez-Parra
- Department of Cell and Developmental Biology, Rocky Mountain Taste and Smell Center and Neuroscience Program, University of Colorado Medical School, Aurora, CO, USA
| | - Anan Li
- Department of Cell and Developmental Biology, Rocky Mountain Taste and Smell Center and Neuroscience Program, University of Colorado Medical School, Aurora, CO, USA; State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, The Chinese Academy of Sciences, Wuhan, China
| | - Diego Restrepo
- Department of Cell and Developmental Biology, Rocky Mountain Taste and Smell Center and Neuroscience Program, University of Colorado Medical School, Aurora, CO, USA.
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20
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Distinct roles of bulbar muscarinic and nicotinic receptors in olfactory discrimination learning. J Neurosci 2014; 34:11244-60. [PMID: 25143606 DOI: 10.1523/jneurosci.1499-14.2014] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The olfactory bulb (OB) and piriform cortex receive dense cholinergic projections from the basal forebrain. Cholinergic modulation within the piriform cortex has long been proposed to serve important functions in olfactory learning and memory. We here investigate how olfactory discrimination learning is regulated by cholinergic modulation of the OB inputs to the piriform cortex. We examined rats' performance on a two-alternative choice odor discrimination task following local, bilateral blockade of cholinergic nicotinic and/or muscarinic receptors in the OB. Results demonstrate that acquisition, but not recall, of novel discrimination problems is impaired following blockade of OB cholinergic receptors, although the relative contribution of muscarinic and nicotinic receptors depends on task difficulty. Blocking muscarinic receptors impairs learning for nearly all odor sets, whereas blocking nicotinic receptors only affects performance for perceptually similar odors. This pattern of behavioral effects is consistent with predictions from a model of cholinergic modulation in the OB and piriform cortex (de Almeida et al., 2013). Model simulations suggest that muscarinic and nicotinic receptors may serve complementary roles in regulating coherence and sparseness of the OB network output, which in turn differentially regulate the strength and overlap in cortical odor representations. Overall, our results suggest that muscarinic receptor blockade results in a bona fide learning impairment that may arise because cortical neurons are activated less often. Behavioral impairment following nicotinic receptor blockade may not be due to the inability of the cortex to learn, but rather arises because the cortex is unable to resolve highly overlapping input patterns.
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21
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Gautam SH, Short SM, Verhagen JV. Retronasal odor concentration coding in glomeruli of the rat olfactory bulb. Front Integr Neurosci 2014; 8:81. [PMID: 25386123 PMCID: PMC4208450 DOI: 10.3389/fnint.2014.00081] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Accepted: 09/26/2014] [Indexed: 11/22/2022] Open
Abstract
The mammalian olfactory system processes odorants presented orthonasally (inhalation through the nose) and also retronasally (exhalation), enabling identification of both external as well as internal objects during food consumption. There are distinct differences between ortho- and retronasal air flow patterns, psychophysics, multimodal integration, and glomerular responses. Recent work indicates that rats can also detect odors retronasally, that rats can associate retronasal odors with tastes, and that their olfactory bulbs (OBs) can respond to retronasal odorants but differently than to orthonasal odors. To further characterize retronasal OB input activity patterns, experiments here focus on determining the effects of odor concentration on glomerular activity by monitoring calcium activity in the dorsal OB of rats using a dextran-conjugated calcium-sensitive dye in vivo. Results showed reliable concentration-response curves that differed between odorants, and recruitment of additional glomeruli, as odor concentration increased. We found evidence of different concentration-response functions between glomeruli, that in turn depended on odor. Further, the relation between dynamics and concentration differed remarkably among retronasal odorants. These dynamics are suggested to reduce the odor map ambiguity based on response amplitude. Elucidating the coding of retronasal odor intensity is fundamental to the understanding of feeding behavior and the neural basis of flavor. These data further establish and refine the rodent model of flavor neuroscience.
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Affiliation(s)
- Shree Hari Gautam
- The John B. Pierce Laboratory New Haven, CT, USA ; Department of Neurobiology, Yale University School of Medicine New Haven, CT, USA
| | - Shaina M Short
- The John B. Pierce Laboratory New Haven, CT, USA ; Department of Neurobiology, Yale University School of Medicine New Haven, CT, USA
| | - Justus V Verhagen
- The John B. Pierce Laboratory New Haven, CT, USA ; Department of Neurobiology, Yale University School of Medicine New Haven, CT, USA
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22
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Zeng HL, Rao X, Zhang LK, Zhao X, Zhang WP, Wang J, Xu F, Guo L. Quantitative proteomics reveals olfactory input-dependent alterations in the mouse olfactory bulb proteome. J Proteomics 2014; 109:125-42. [PMID: 24998433 DOI: 10.1016/j.jprot.2014.06.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2014] [Revised: 06/17/2014] [Accepted: 06/23/2014] [Indexed: 02/04/2023]
Abstract
UNLABELLED Olfactory sensory information is processed and integrated by circuits within the olfactory bulb (OB) before being sent to the olfactory cortex. In the mammalian OB, neural activity driven by external stimuli can lead to experience-dependent changes in structures and functions. In this study, quantitative proteomics techniques were employed to study proteome-wide changes in the OB under four levels of neural activity (from low to high): devoid of peripheral input (using a transgenic model), wild-type control, and short-term and long-term odor exposures. Our results revealed that proteins related to various processes were altered in the OBs of odor-deprived and odor-stimulated mice compared to the wild-type controls. These changes induced by odor stimulation were quite different from those induced by a deficit in peripheral olfactory inputs. Detailed analysis demonstrated that metabolic process and synaptic transmission were the most commonly altered pathways and that the effects of peripheral deprivation were more profound. Our comparative proteomics analysis indicated that olfactory deprivation and odor exposure lead to different alterations in the OB proteome, which provides new clues about the mechanisms underlying the olfactory deprivation- or odor stimulation-induced plasticity of OB function and organization. BIOLOGICAL SIGNIFICANCE By combining quantitative proteomics, bioinformatics and WB/IHC analysis, this study reports the results of the first comparative study on proteome-wide changes in the olfactory bulb under different levels of olfactory input. Odor deprivation and stimulation induced proteomic changes clearly demonstrate significant metabolic shifts and alterations on synaptic transmission. This quantitative system biology study leads to a new level of understanding in the development of olfactory bulb plasticity induced by odor deprivation or stimulation, and provides many new clues for the olfactory bulb related functional studies.
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Affiliation(s)
- Hao-Long Zeng
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Xiaoping Rao
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, China
| | - Lei-Ke Zhang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Xiaolu Zhao
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Wei-Ping Zhang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Jie Wang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, China
| | - Fuqiang Xu
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, China.
| | - Lin Guo
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China.
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23
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Osmanski B, Martin C, Montaldo G, Lanièce P, Pain F, Tanter M, Gurden H. Functional ultrasound imaging reveals different odor-evoked patterns of vascular activity in the main olfactory bulb and the anterior piriform cortex. Neuroimage 2014; 95:176-84. [DOI: 10.1016/j.neuroimage.2014.03.054] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Revised: 03/05/2014] [Accepted: 03/11/2014] [Indexed: 11/29/2022] Open
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24
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Imahashi M, Watanabe M, Jha SK, Hayashi K. Olfaction-inspired sensing using a sensor system with molecular recognition and optimal classification ability for comprehensive detection of gases. SENSORS 2014; 14:5221-38. [PMID: 24625745 PMCID: PMC4003990 DOI: 10.3390/s140305221] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 02/20/2014] [Accepted: 03/10/2014] [Indexed: 11/20/2022]
Abstract
In this study, we examined the comprehensive detection of numerous volatile molecules based on the olfactory information constructed by using olfaction-inspired sensor technology. The sensor system can simultaneously detect multiple odors by the separation and condensation ability of molecularly imprinted filtering adsorbents (MIFAs), where a MIP filter with a molecular sieve was deposited on a polydimethylsiloxane (PDMS) substrate. The adsorption properties of MIFAs were evaluated using the solid-phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS). The results demonstrated that the system embedded with MIFAs possesses high sensitivity and specific selectivity. The digitization and comprehensive classification of odors were accomplished by using artificial odor maps constructed through this system.
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Affiliation(s)
- Masahiro Imahashi
- Department of Electronics, Graduate School of Information Science and Electrical Engineering, Kyushu University, 744 Motooka, Fukuoka 819-0395, Japan.
| | - Masashi Watanabe
- Department of Electronics, Graduate School of Information Science and Electrical Engineering, Kyushu University, 744 Motooka, Fukuoka 819-0395, Japan.
| | - Sunil Kumar Jha
- Department of Electronics, Graduate School of Information Science and Electrical Engineering, Kyushu University, 744 Motooka, Fukuoka 819-0395, Japan.
| | - Kenshi Hayashi
- Department of Electronics, Graduate School of Information Science and Electrical Engineering, Kyushu University, 744 Motooka, Fukuoka 819-0395, Japan.
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25
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Single Scale for Odor Intensity in Rat Olfaction. Curr Biol 2014; 24:568-73. [DOI: 10.1016/j.cub.2014.01.059] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Revised: 01/08/2014] [Accepted: 01/28/2014] [Indexed: 11/20/2022]
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26
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Kaplan BA, Lansner A. A spiking neural network model of self-organized pattern recognition in the early mammalian olfactory system. Front Neural Circuits 2014; 8:5. [PMID: 24570657 PMCID: PMC3916767 DOI: 10.3389/fncir.2014.00005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Accepted: 01/09/2014] [Indexed: 01/01/2023] Open
Abstract
Olfactory sensory information passes through several processing stages before an odor percept emerges. The question how the olfactory system learns to create odor representations linking those different levels and how it learns to connect and discriminate between them is largely unresolved. We present a large-scale network model with single and multi-compartmental Hodgkin-Huxley type model neurons representing olfactory receptor neurons (ORNs) in the epithelium, periglomerular cells, mitral/tufted cells and granule cells in the olfactory bulb (OB), and three types of cortical cells in the piriform cortex (PC). Odor patterns are calculated based on affinities between ORNs and odor stimuli derived from physico-chemical descriptors of behaviorally relevant real-world odorants. The properties of ORNs were tuned to show saturated response curves with increasing concentration as seen in experiments. On the level of the OB we explored the possibility of using a fuzzy concentration interval code, which was implemented through dendro-dendritic inhibition leading to winner-take-all like dynamics between mitral/tufted cells belonging to the same glomerulus. The connectivity from mitral/tufted cells to PC neurons was self-organized from a mutual information measure and by using a competitive Hebbian-Bayesian learning algorithm based on the response patterns of mitral/tufted cells to different odors yielding a distributed feed-forward projection to the PC. The PC was implemented as a modular attractor network with a recurrent connectivity that was likewise organized through Hebbian-Bayesian learning. We demonstrate the functionality of the model in a one-sniff-learning and recognition task on a set of 50 odorants. Furthermore, we study its robustness against noise on the receptor level and its ability to perform concentration invariant odor recognition. Moreover, we investigate the pattern completion capabilities of the system and rivalry dynamics for odor mixtures.
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Affiliation(s)
- Bernhard A Kaplan
- Department of Computational Biology, School of Computer Science and Communication, Royal Institute of Technology Stockholm, Sweden ; Stockholm Brain Institute, Karolinska Institute Stockholm, Sweden
| | - Anders Lansner
- Department of Computational Biology, School of Computer Science and Communication, Royal Institute of Technology Stockholm, Sweden ; Stockholm Brain Institute, Karolinska Institute Stockholm, Sweden ; Department of Numerical Analysis and Computer Science, Stockholm University Stockholm, Sweden
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27
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Yoder WM, Setlow B, Bizon JL, Smith DW. Characterizing olfactory perceptual similarity using carbon chain discrimination in Fischer 344 rats. Chem Senses 2014; 39:323-31. [PMID: 24488965 DOI: 10.1093/chemse/bju001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Performance on olfactory tests can be influenced by a number of stimulus characteristics including chemical structure, concentration, perceptual similarity, and previous experience with the test odorants. Few of these parameters have been extensively characterized in the Fischer 344 rat strain. To investigate how odor quality affects perception in this rat strain, we measured how graded perceptual similarity, created by varying carbon chain length across a series of homologous alcohol pairs, influenced odor discrimination using a liquid-motivated go/no-go task. We employed an automated, liquid-dilution olfactometer to train Fischer 344 rats (N = 8) on a 2-odor discrimination task. Six odorants (1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol, and 1-octanol) were arranged to produce 15 novel odorant pairs differing between 1 and 5 carbon atoms; testing sessions included presentation of only 1 pseudorandomly assigned pair daily (200 trials). Results show that although rats can learn to discriminate between any 2 odorant pairs, performance declines systematically as the pairs become more structurally similar and, therefore, more perceptually confusing. As such, the easier discrimination pairs produced reliable ceiling effects across all rats, whereas performance for the difficult discrimination pairs was consistently worse, even after repeated testing. These data emphasize the importance of considering odorant stimulus dimensions in experimental designs employing olfactory stimuli. Moreover, establishing baseline olfactory performance in Fischer 344 rats may be particularly useful for predicting age-related cognitive decline in this model.
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Affiliation(s)
- Wendy M Yoder
- Department of Psychology, University of Florida, 114 Psychology Building, PO Box 11250, Gainesville, FL 32611, USA.
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28
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Bracey EF, Pichler B, Schaefer AT, Wallace DJ, Margrie TW. Perceptual judgements and chronic imaging of altered odour maps indicate comprehensive stimulus template matching in olfaction. Nat Commun 2013; 4:2100. [PMID: 23820818 PMCID: PMC3715885 DOI: 10.1038/ncomms3100] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Accepted: 06/03/2013] [Indexed: 11/09/2022] Open
Abstract
Lesion experiments suggest that odour input to the olfactory bulb contains significant redundant signal such that rodents can discern odours using minimal stimulus-related information. Here we investigate the dependence of odour-quality perception on the integrity of glomerular activity by comparing odour-evoked activity maps before and after epithelial lesions. Lesions prevent mice from recognizing previously experienced odours and differentially delay discrimination learning of unrecognized and novel odour pairs. Poor recognition results not from mice experiencing an altered concentration of an odour but from perception of apparent novel qualities. Consistent with this, relative intensity of glomerular activity following lesions is altered compared with maps recorded in shams and by varying odour concentration. Together, these data show that odour recognition relies on comprehensively matching input patterns to a previously generated stimulus template. When encountering novel odours, access to all glomerular activity ensures rapid generation of new templates to perform accurate perceptual judgements.
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Affiliation(s)
- Edward F Bracey
- Department of Neuroscience, Physiology and Pharmacology, University College London, University Street, London, UK
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29
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Shirasu M, Yoshikawa K, Takai Y, Nakashima A, Takeuchi H, Sakano H, Touhara K. Olfactory receptor and neural pathway responsible for highly selective sensing of musk odors. Neuron 2013; 81:165-78. [PMID: 24361078 DOI: 10.1016/j.neuron.2013.10.021] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/04/2013] [Indexed: 11/27/2022]
Abstract
Musk odorants are used widely in cosmetic industries because of their fascinating animalic scent. However, how this aroma is perceived in the mammalian olfactory system remains a great mystery. Here, we show that muscone, one musk odor secreted by various animals from stink glands, activates a few glomeruli clustered in a neuroanatomically unique anteromedial olfactory bulb. The muscone-responsive glomeruli are highly specific to macrocyclic ketones; interestingly, other synthetic musk odorants with nitro or polycyclic moieties or ester bonds activate distinct but nearby glomeruli. Anterodorsal bulbar lesions cause muscone anosmia, suggesting that this region is involved in muscone perception. Finally, we identified the mouse olfactory receptor, MOR215-1, that was a specific muscone receptor expressed by neurons innervating the muscone-responsive anteromedial glomeruli and also the human muscone receptor, OR5AN1. The current study documents the olfactory neural pathway in mice that senses and transmits musk signals from receptor to brain.
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Affiliation(s)
- Mika Shirasu
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan; ERATO Touhara Chemosensory Signal Project, JST, The University of Tokyo, Tokyo 113-8657, Japan
| | - Keiichi Yoshikawa
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan
| | - Yoshiki Takai
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan
| | - Ai Nakashima
- Department of Brain Function, School of Medical Science, University of Fukui, Fukui 910-1193, Japan
| | - Haruki Takeuchi
- Department of Brain Function, School of Medical Science, University of Fukui, Fukui 910-1193, Japan
| | - Hitoshi Sakano
- Department of Brain Function, School of Medical Science, University of Fukui, Fukui 910-1193, Japan
| | - Kazushige Touhara
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan; ERATO Touhara Chemosensory Signal Project, JST, The University of Tokyo, Tokyo 113-8657, Japan.
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30
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Auffarth B. Understanding smell—The olfactory stimulus problem. Neurosci Biobehav Rev 2013; 37:1667-79. [DOI: 10.1016/j.neubiorev.2013.06.009] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Revised: 05/09/2013] [Accepted: 06/13/2013] [Indexed: 01/30/2023]
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31
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Spatiotemporal alterations in primary odorant representations in olfactory marker protein knockout mice. PLoS One 2013; 8:e61431. [PMID: 23630588 PMCID: PMC3632605 DOI: 10.1371/journal.pone.0061431] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Accepted: 03/11/2013] [Indexed: 11/19/2022] Open
Abstract
Olfactory marker protein (OMP) is highly and selectively expressed in primary olfactory sensory neurons (OSNs) across species, but its physiological function remains unclear. Previous studies in the olfactory epithelium suggest that it accelerates the neural response to odorants and may modulate the odorant-selectivity of OSNs. Here we used a line of gene-targeted mice that express the fluorescent exocytosis indicator synaptopHluorin in place of OMP to compare spatiotemporal patterns of odorant-evoked neurotransmitter release from OSNs in adult mice that were heterozygous for OMP or OMP-null. We found that these patterns, which constitute the primary neural representation of each odorant, developed more slowly during the odorant presentation in OMP knockout mice but eventually reached the same magnitude as in heterozygous mice. In the olfactory bulb, each glomerulus receives synaptic input from a subpopulation of OSNs that all express the same odor receptor and thus typically respond to a specific subset of odorants. We observed that in OMP knockout mice, OSNs innervating a given glomerulus typically responded to a broader range of odorants than in OMP heterozygous mice and thus each odorant evoked synaptic input to a larger number of glomeruli. In an olfactory habituation task, OMP knockout mice behaved differently than wild-type mice, exhibiting a delay in their onset to investigate an odor stimulus during its first presentation and less habituation to that stimulus over repeated presentations. These results suggest that the actions of OMP in olfactory transduction carry through to the primary sensory representations of olfactory stimuli in adult mice in vivo.
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Furudono Y, Cruz G, Lowe G. Glomerular input patterns in the mouse olfactory bulb evoked by retronasal odor stimuli. BMC Neurosci 2013; 14:45. [PMID: 23565900 PMCID: PMC3626767 DOI: 10.1186/1471-2202-14-45] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Accepted: 04/03/2013] [Indexed: 12/05/2022] Open
Abstract
Background Odorant stimuli can access the olfactory epithelium either orthonasally, by inhalation through the external nares, or retronasally by reverse airflow from the oral cavity. There is evidence that odors perceived through these two routes can differ in quality and intensity. We were curious whether such differences might potentially have a neural basis in the peripheral mechanisms of odor coding. To explore this possibility, we compared olfactory receptor input to glomeruli in the dorsal olfactory bulb evoked by orthonasal and retronasal stimulation. Maps of glomerular response were acquired by optical imaging of transgenic mice expressing synaptopHluorin (spH), a fluorescent reporter of presynaptic activity, in olfactory nerve terminals. Results We found that retronasally delivered odorants were able to activate inputs to multiple glomeruli in the dorsal olfactory bulb. The retronasal responses were smaller than orthonasal responses to odorants delivered at comparable concentrations and flow rates, and they displayed higher thresholds and right-shifted dose–response curves. Glomerular maps of orthonasal and retronasal responses were usually well overlapped, with fewer total numbers of glomeruli in retronasal maps. However, maps at threshold could be quite distinct with little overlap. Retronasal responses were also more narrowly tuned to homologous series of aliphatic odorants of varying carbon chain length, with longer chain, more hydrophobic compounds evoking little or no response at comparable vapor levels. Conclusions Several features of retronasal olfaction are possibly referable to the observed properties of glomerular odorant responses. The finding that retronasal responses are weaker and sparser than orthonasal responses is consistent with psychophysical studies showing lower sensitivity for retronasal olfaction in threshold and suprathreshold tests. The similarity and overlap of orthonasal and retronasal odor maps at suprathreshold concentrations agrees with generally similar perceived qualities for the same odorant stimuli administered by the two routes. However, divergence of maps near threshold is a potential factor in perceptual differences between orthonasal and retronasal olfaction. Narrower tuning of retronasal responses suggests that they may be less influenced by chromatographic adsorption effects.
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Abstract
The olfactory system encodes information about molecules by spatiotemporal patterns of activity across distributed populations of neurons and extracts information from these patterns to control specific behaviors. Recent studies used in vivo recordings, optogenetics, and other methods to analyze the mechanisms by which odor information is encoded and processed in the olfactory system, the functional connectivity within and between olfactory brain areas, and the impact of spatiotemporal patterning of neuronal activity on higher-order neurons and behavioral outputs. The results give rise to a faceted picture of olfactory processing and provide insights into fundamental mechanisms underlying neuronal computations. This review focuses on some of this work presented in a Mini-Symposium at the Annual Meeting of the Society for Neuroscience in 2012.
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Kass MD, Pottackal J, Turkel DJ, McGann JP. Changes in the neural representation of odorants after olfactory deprivation in the adult mouse olfactory bulb. Chem Senses 2012; 38:77-89. [PMID: 23125347 DOI: 10.1093/chemse/bjs081] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Olfactory sensory deprivation during development has been shown to induce significant alterations in the neurophysiology of olfactory receptor neurons (ORNs), the primary sensory inputs to the brain's olfactory bulb. Deprivation has also been shown to alter the neurochemistry of the adult olfactory system, but the physiological consequences of these changes are poorly understood. Here we used in vivo synaptopHluorin (spH) imaging to visualize odorant-evoked neurotransmitter release from ORNs in adult transgenic mice that underwent 4 weeks of unilateral olfactory deprivation. Deprivation reduced odorant-evoked spH signals compared with sham-occluded mice. Unexpectedly, this reduction was equivalent between ORNs on the open and plugged sides. Changes in odorant selectivity of glomerular subpopulations of ORNs were also observed, but only in ORNs on the open side of deprived mice. These results suggest that naris occlusion in adult mice produces substantial changes in primary olfactory processing which may reflect not only the decrease in olfactory stimulation on the occluded side but also the alteration of response properties on the intact side. We also observed a modest effect of true sham occlusions that included noseplug insertion and removal, suggesting that conventional noseplug techniques may have physiological effects independent of deprivation per se and thus require more careful controls than has been previously appreciated.
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Affiliation(s)
- Marley D Kass
- Behavioral and Systems Neuroscience Section, Department of Psychology, Rutgers, The State University of New Jersey, USA
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35
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Chen Q, Cichon J, Wang W, Qiu L, Lee SJR, Campbell NR, Destefino N, Goard MJ, Fu Z, Yasuda R, Looger LL, Arenkiel BR, Gan WB, Feng G. Imaging neural activity using Thy1-GCaMP transgenic mice. Neuron 2012; 76:297-308. [PMID: 23083733 DOI: 10.1016/j.neuron.2012.07.011] [Citation(s) in RCA: 156] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/03/2012] [Indexed: 12/23/2022]
Abstract
The ability to chronically monitor neuronal activity in the living brain is essential for understanding the organization and function of the nervous system. The genetically encoded green fluorescent protein-based calcium sensor GCaMP provides a powerful tool for detecting calcium transients in neuronal somata, processes, and synapses that are triggered by neuronal activities. Here we report the generation and characterization of transgenic mice that express improved GCaMPs in various neuronal subpopulations under the control of the Thy1 promoter. In vitro and in vivo studies show that calcium transients induced by spontaneous and stimulus-evoked neuronal activities can be readily detected at the level of individual cells and synapses in acute brain slices, as well as chronically in awake, behaving animals. These GCaMP transgenic mice allow investigation of activity patterns in defined neuronal populations in the living brain and will greatly facilitate dissecting complex structural and functional relationships of neural networks.
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Affiliation(s)
- Qian Chen
- McGovern Institute for Brain Research, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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Blanco-Hernández E, Valle-Leija P, Zomosa-Signoret V, Drucker-Colín R, Vidaltamayo R. Odor memory stability after reinnervation of the olfactory bulb. PLoS One 2012; 7:e46338. [PMID: 23071557 PMCID: PMC3468571 DOI: 10.1371/journal.pone.0046338] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Accepted: 08/31/2012] [Indexed: 11/19/2022] Open
Abstract
The olfactory system, particularly the olfactory epithelium, presents a unique opportunity to study the regenerative capabilities of the brain, because of its ability to recover after damage. In this study, we ablated olfactory sensory neurons with methimazole and followed the anatomical and functional recovery of circuits expressing genetic markers for I7 and M72 receptors (M72-IRES-tau-LacZ and I7-IRES-tau-GFP). Our results show that 45 days after methimazole-induced lesion, axonal projections to the bulb of M72 and I7 populations are largely reestablished. Furthermore, regenerated glomeruli are re-formed within the same areas as those of control, unexposed mice. This anatomical regeneration correlates with functional recovery of a previously learned odorant-discrimination task, dependent on the cognate ligands for M72 and I7. Following regeneration, mice also recover innate responsiveness to TMT and urine. Our findings show that regeneration of neuronal circuits in the olfactory system can be achieved with remarkable precision and underscore the importance of glomerular organization to evoke memory traces stored in the brain.
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Affiliation(s)
- Eduardo Blanco-Hernández
- Departamento de Neuropatología Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Distrito Federal, México
| | - Pablo Valle-Leija
- Departamento de Neuropatología Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Distrito Federal, México
| | - Viviana Zomosa-Signoret
- Departamento de Bioquímica, Facultad de Medicina, Universidad Autónoma de Nuevo León, Nuevo León, México
| | - René Drucker-Colín
- Departamento de Neuropatología Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Distrito Federal, México
| | - Román Vidaltamayo
- Departamento de Ciencias Básicas, Centro de Diagnóstico Molecular y Medicina Personalizada, Universidad de Monterrey, Nuevo León, México
- * E-mail:
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Abstract
Animals perceive their olfactory environment not only from odors originating in the external world (orthonasal route) but also from odors released in the oral cavity while eating food (retronasal route). Retronasal olfaction is crucial for the perception of food flavor in humans. However, little is known about the retronasal stimulus coding in the brain. The most basic questions are if and how route affects the odor representations at the level of the olfactory bulb (OB), where odor quality codes originate. We used optical calcium imaging of presynaptic dorsal OB responses to odorants in anesthetized rats to ask whether the rat OB could be activated retronasally, and how these responses compare to orthonasal responses under similar conditions. We further investigated the effects of specific odorant properties on orthonasal versus retronasal response patterns. We found that at a physiologically relevant flow rate, retronasal odorants can effectively reach the olfactory receptor neurons, eliciting glomerular response patterns that grossly overlap with those of orthonasal responses, but differ from the orthonasal patterns in the response amplitude and temporal dynamics. Interestingly, such differences correlated well with specific odorant properties. Less volatile odorants yielded relatively smaller responses retronasally, but volatility did not affect relative temporal profiles. More polar odorants responded with relatively longer onset latency and time to peak retronasally, but polarity did not affect relative response magnitudes. These data provide insight into the early stages of retronasal stimulus coding and establish relationships between orthonasal and retronasal odor representations in the rat OB.
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Fonollosa J, Gutierrez-Galvez A, Marco S. Quality coding by neural populations in the early olfactory pathway: analysis using information theory and lessons for artificial olfactory systems. PLoS One 2012; 7:e37809. [PMID: 22719851 PMCID: PMC3377695 DOI: 10.1371/journal.pone.0037809] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Accepted: 04/23/2012] [Indexed: 01/08/2023] Open
Abstract
In this article, we analyze the ability of the early olfactory system to detect and discriminate different odors by means of information theory measurements applied to olfactory bulb activity images. We have studied the role that the diversity and number of receptor neuron types play in encoding chemical information. Our results show that the olfactory receptors of the biological system are low correlated and present good coverage of the input space. The coding capacity of ensembles of olfactory receptors with the same receptive range is maximized when the receptors cover half of the odor input space - a configuration that corresponds to receptors that are not particularly selective. However, the ensemble's performance slightly increases when mixing uncorrelated receptors of different receptive ranges. Our results confirm that the low correlation between sensors could be more significant than the sensor selectivity for general purpose chemo-sensory systems, whether these are biological or biomimetic.
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Affiliation(s)
- Jordi Fonollosa
- Department of Electronics, Universitat de Barcelona, Barcelona, Spain
- Artificial Olfaction Group, Institute for Bioengineering of Catalonia, Barcelona, Spain
| | - Agustin Gutierrez-Galvez
- Department of Electronics, Universitat de Barcelona, Barcelona, Spain
- Artificial Olfaction Group, Institute for Bioengineering of Catalonia, Barcelona, Spain
| | - Santiago Marco
- Department of Electronics, Universitat de Barcelona, Barcelona, Spain
- Artificial Olfaction Group, Institute for Bioengineering of Catalonia, Barcelona, Spain
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Carcaud J, Hill T, Giurfa M, Sandoz JC. Differential coding by two olfactory subsystems in the honeybee brain. J Neurophysiol 2012; 108:1106-21. [PMID: 22572948 DOI: 10.1152/jn.01034.2011] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Sensory systems use parallel processing to extract and process different features of environmental stimuli. Parallel processing has been studied in the auditory, visual, and somatosensory systems, but equivalent research in the olfactory modality is scarce. The honeybee Apis mellifera is an interesting model for such research as its relatively simple brain contains a dual olfactory system, with a clear neural dichotomy from the periphery to higher-order centers, based on two main neuronal tracts [medial (m) and lateral (l) antenno-protocerebral tract (APT)]. The function of this dual system is as yet unknown, and attributes like odor quality and odor quantity might be separately encoded in these subsystems. We have thus studied olfactory coding at the input of both subsystems, using in vivo calcium imaging. As one of the subsystems (m-APT) has never been imaged before, a novel imaging preparation was developed to this end, and responses to a panel of aliphatic odorants at different concentrations were compared in both subsystems. Our data show a global redundancy of olfactory coding at the input of both subsystems but unravel some specificities for encoding chemical group and carbon chain length of odor molecules.
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Affiliation(s)
- Julie Carcaud
- Université de Toulouse (UPS), Centre de Recherches sur la Cognition Animale, Toulouse Cedex, France
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40
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Can Güven S, Laska M. Olfactory sensitivity and odor structure-activity relationships for aliphatic carboxylic acids in CD-1 mice. PLoS One 2012; 7:e34301. [PMID: 22479594 PMCID: PMC3316622 DOI: 10.1371/journal.pone.0034301] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Accepted: 02/27/2012] [Indexed: 12/21/2022] Open
Abstract
Using a conditioning paradigm, the olfactory sensitivity of CD-1 mice for a homologous series of aliphatic n-carboxylic acids (ethanoic acid to n-octanoic acid) and several of their isomeric forms was investigated. With all 14 odorants, the animals significantly discriminated concentrations as low as 0.03 ppm (parts per million) from the solvent, and with four odorants the best-scoring animals even detected concentrations as low as 3 ppt (parts per trillion). Analysis of odor structure-activity relationships showed that the correlation between olfactory detection thresholds of the mice for the unbranched carboxylic acids and carbon chain length can best be described as a U-shaped function with the lowest threshold values at n-butanoic acid. A significant positive correlation between olfactory detection thresholds and carbon chain length of the carboxylic acids with their branching next to the functional carboxyl group was found. In contrast, no such correlation was found for carboxylic acids with their branching at the distal end of the carbon chain relative to the functional carboxyl group. Finally, a significant correlation was found between olfactory detection thresholds and the position of the branching of the carboxylic acids. Across-species comparisons suggest that mice are more sensitive for short-chained (C2 to C4) aliphatic n-carboxylic acids than other mammalian species, but not for longer-chained ones (C5 to C8). Further comparisons suggest that odor structure-activity relationships are both substance class- and species-specific.
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Affiliation(s)
| | - Matthias Laska
- Department of Physics, Chemistry and Biology, Linköping University, Linköping, Sweden
- * E-mail:
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41
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Falasconi M, Gutierrez-Galvez A, Leon M, Johnson BA, Marco S. Cluster analysis of rat olfactory bulb responses to diverse odorants. Chem Senses 2012; 37:639-53. [PMID: 22459165 DOI: 10.1093/chemse/bjs045] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In an effort to deepen our understanding of mammalian olfactory coding, we have used an objective method to analyze a large set of odorant-evoked activity maps collected systematically across the rat olfactory bulb to determine whether such an approach could identify specific glomerular regions that are activated by related odorants. To that end, we combined fuzzy c-means clustering methods with a novel validity approach based on cluster stability to evaluate the significance of the fuzzy partitions on a data set of glomerular layer responses to a large diverse group of odorants. Our results confirm the existence of glomerular response clusters to similar odorants. They further indicate a partial hierarchical chemotopic organization wherein larger glomerular regions can be subdivided into smaller areas that are rather specific in their responses to particular functional groups of odorants. These clusters bear many similarities to, as well as some differences from, response domains previously proposed for the glomerular layer of the bulb. These data also provide additional support for the concept of an identity code in the mammalian olfactory system.
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Affiliation(s)
- Matteo Falasconi
- Department of Chemistry and Physics, University of Brescia and CNR-IDASC, Via Valotti 9, 25133 Brescia, Italy
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42
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Cleland TA, Chen SYT, Hozer KW, Ukatu HN, Wong KJ, Zheng F. Sequential mechanisms underlying concentration invariance in biological olfaction. FRONTIERS IN NEUROENGINEERING 2012; 4:21. [PMID: 22287949 PMCID: PMC3251820 DOI: 10.3389/fneng.2011.00021] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Accepted: 12/19/2011] [Indexed: 11/13/2022]
Abstract
Concentration invariance-the capacity to recognize a given odorant (analyte) across a range of concentrations-is an unusually difficult problem in the olfactory modality. Nevertheless, humans and other animals are able to recognize known odors across substantial concentration ranges, and this concentration invariance is a highly desirable property for artificial systems as well. Several properties of olfactory systems have been proposed to contribute to concentration invariance, but none of these alone can plausibly achieve full concentration invariance. We here propose that the mammalian olfactory system uses at least six computational mechanisms in series to reduce the concentration-dependent variance in odor representations to a level at which different concentrations of odors evoke reasonably similar representations, while preserving variance arising from differences in odor quality. We suggest that the residual variance then is treated like any other source of stimulus variance, and categorized appropriately into "odors" via perceptual learning. We further show that naïve mice respond to different concentrations of an odorant just as if they were differences in quality, suggesting that, prior to odor categorization, the learning-independent compensatory mechanisms are limited in their capacity to achieve concentration invariance.
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Affiliation(s)
- Thomas A Cleland
- Computational Physiology Laboratory, Department of Psychology, Cornell University, Ithaca NY, USA
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43
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Auffarth B, Kaplan B, Lansner A. Map formation in the olfactory bulb by axon guidance of olfactory neurons. Front Syst Neurosci 2011; 5:84. [PMID: 22013417 PMCID: PMC3190187 DOI: 10.3389/fnsys.2011.00084] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Accepted: 09/22/2011] [Indexed: 11/28/2022] Open
Abstract
The organization of representations in the brain has been observed to locally reflect subspaces of inputs that are relevant to behavioral or perceptual feature combinations, such as in areas receptive to lower and higher-order features in the visual system. The early olfactory system developed highly plastic mechanisms and convergent evidence indicates that projections from primary neurons converge onto the glomerular level of the olfactory bulb (OB) to form a code composed of continuous spatial zones that are differentially active for particular physico-chemical feature combinations, some of which are known to trigger behavioral responses. In a model study of the early human olfactory system, we derive a glomerular organization based on a set of real-world, biologically relevant stimuli, a distribution of receptors that respond each to a set of odorants of similar ranges of molecular properties, and a mechanism of axon guidance based on activity. Apart from demonstrating activity-dependent glomeruli formation and reproducing the relationship of glomerular recruitment with concentration, it is shown that glomerular responses reflect similarities of human odor category perceptions and that further, a spatial code provides a better correlation than a distributed population code. These results are consistent with evidence of functional compartmentalization in the OB and could suggest a function for the bulb in encoding of perceptual dimensions.
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Affiliation(s)
- Benjamin Auffarth
- Department of Computational Biology, Royal Institute of Technology Stockholm, Sweden
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44
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Pain F, L'heureux B, Gurden H. Visualizing odor representation in the brain: a review of imaging techniques for the mapping of sensory activity in the olfactory glomeruli. Cell Mol Life Sci 2011; 68:2689-709. [PMID: 21584811 PMCID: PMC11114686 DOI: 10.1007/s00018-011-0708-4] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2010] [Revised: 03/30/2011] [Accepted: 04/21/2011] [Indexed: 01/15/2023]
Abstract
The brain transforms clues from the external world, the sensory stimuli, into activities in neuroglial networks. These circuits are activated in specialized sensory cortices where specific functional modules are responsible for the spatiotemporal coding of the stimulus. A major challenge in the neuroscience field has been to image the spatial distribution and follow the temporal dynamics of the activation of such large populations in vivo. Functional imaging techniques developed in the last 30 years have enabled researchers to solve this critical issue, and are reviewed here. These techniques utilize sources of contrast of radioisotopic, magnetic and optical origins and exploit two major families of signals to image sensory activity: the first class uses sources linked to cellular energy metabolism and hemodynamics, while the second involves exogenous indicators of neuronal activity. The whole panel of imaging techniques has fostered the functional exploration of the olfactory bulb which is one of the most studied sensory structures. We summarize the major results obtained using these techniques that describe the spatial and temporal activity patterns in the olfactory glomeruli, the first relay of olfactory information processing in the main olfactory bulb. We conclude this review by describing promising technical developments in optical imaging and future directions in the study of olfactory spatiotemporal coding.
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Affiliation(s)
- F Pain
- Laboratoire Imagerie et Modélisation en Neurobiologie et Cancérologie, UMR Université Paris Sud, CNRS, Campus d'Orsay Bat, France.
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45
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Masurkar AV, Chen WR. Potassium currents of olfactory bulb juxtaglomerular cells: characterization, simulation, and implications for plateau potential firing. Neuroscience 2011; 192:247-62. [PMID: 21704678 DOI: 10.1016/j.neuroscience.2011.06.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Revised: 05/06/2011] [Accepted: 06/03/2011] [Indexed: 12/23/2022]
Abstract
Odor identity is encoded by the activity of olfactory bulb glomeruli, which receive primary sensory input and transfer it to projection neurons. Juxtaglomerular cells (JGCs) may influence glomerular processing via firing of long lasting plateau potentials. Though inward currents have been investigated, little is known regarding potassium current contribution to JGC plateau potentials. We pursued study of these currents, with the overarching goal of creating components for a computational model of JGC plateau potential firing. In conditions minimizing calcium-activated potassium current (I(K(Ca))), we used whole cell voltage clamp and in vitro slice preparations to characterize three potassium currents in rat JGCs. The prominent component I(kt1) displayed rapid kinetics (τ(10%-90% rise), 0.6-2 ms; τ(inactivation), 5-10 ms) and was blocked by high concentration 4-aminopyridine (4-AP) (5 mM) and tetramethylammonium (TEA) (40 mM). It had half maximal activation at -10 mV (V(½)max) and little inactivation at rest. I(kt2), with slower kinetics (τ(10%-90% rise), 11-15 ms; τ(inactivation), 100-300 ms), was blocked by low concentration 4-AP (0.5 mM) and TEA (5 mM). The V(½)max was 0 mV and inactivation was also minimal at rest. Sustained current I(kt3) showed sensitivity to low concentration 4-AP and TEA, and had V(½)max of +10 mV. Further experiments, in conditions of physiologic calcium buffering, suggested that I(K(Ca)) contributed to I(kt3) with minimal effect on plateau potential evolution. We transformed these characterizations into Hodgkin-Huxley models that robustly mimicked experimental data. Further simulation demonstrated that I(kt1) would be most efficiently activated by plateau potential waveforms, predicting a critical role in shaping JGC firing. These studies demonstrated that JGCs possess a unique potassium current profile, with delayed rectifier (I(kt3)), atypical A-current (I(kt1)), and D-current (I(kt2)) in accordance with known expression patterns in olfactory bulb (OB) glomeruli. Our simulations also provide an initial framework for more integrative models of JGC plateau potential firing.
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Affiliation(s)
- A V Masurkar
- Department of Neurobiology, Yale University School of Medicine, New Haven, CT 06520, USA.
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Masurkar AV, Chen WR. Calcium currents of olfactory bulb juxtaglomerular cells: profile and multiple conductance plateau potential simulation. Neuroscience 2011; 192:231-46. [PMID: 21704681 DOI: 10.1016/j.neuroscience.2011.06.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Revised: 05/06/2011] [Accepted: 06/03/2011] [Indexed: 11/25/2022]
Abstract
The olfactory glomerulus is the locus of information transfer between olfactory sensory neurons and output neurons of the olfactory bulb. Juxtaglomerular cells (JGCs) may influence intraglomerular processing by firing plateau potentials that support multiple spikes. It is unclear what inward currents mediate this firing pattern. In previous work, we characterized potassium currents of JGCs. We focus here on the inward currents using whole cell current clamp and voltage recording in a rat in vitro slice preparation, as well as computer simulation. We first showed that sodium current was not required to mediate plateau potentials. Voltage clamp characterization of calcium current (I(Ca)) determined that I(Ca) consisted of a slow activating, rapidly inactivating (τ(10%-90% rise) 6-8 ms, τ(inactivation) 38-77 ms) component I(cat1), similar to T-type currents, and a sustained (τ(inactivation)>>500 ms) component I(cat2), likely composed of L-type and P/Q-type currents. We used computer simulation to test their roles in plateau potential firing. We robustly modeled I(cat1) and I(cat2) to Hodgkin-Huxley schemes (m(3)h and m(2), respectively) and simulated a JGC plateau potential with six conductances: calcium currents as above, potassium currents from our prior study (A-type I(kt1), D-type I(kt2), delayed rectifier I(kt3)), and a fast sodium current (I(Na)). We demonstrated that I(cat1) was required for mediating the plateau potential, unlike I(Na) and I(cat2), and its τ(inactivation) determined plateau duration. We also found that I(kt1) dictated plateau potential shape more than I(kt2) and I(kt3). The influence of these two transient and opposing conductances suggests a unique mechanism of plateau potential physiology.
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Affiliation(s)
- A V Masurkar
- Department of Neurobiology, Yale University School of Medicine, New Haven, CT 06520, USA.
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47
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Raman B, Stopfer M, Semancik S. Mimicking biological design and computing principles in artificial olfaction. ACS Chem Neurosci 2011; 2:487-499. [PMID: 22081790 DOI: 10.1021/cn200027r] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Biology has inspired solutions to many engineering problems, including chemical sensing. Modern approaches to chemical sensing have been based on the biological principle of combining cross-selective chemical sensors with a pattern recognition engine to identify odors. Here, we review some recent advances made in mimicking biological design and computing principles to develop an electronic nose. The resulting technology will have important applications in fundamental biological research, as well as in industrial, security, and medical domains.
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Affiliation(s)
- Baranidharan Raman
- Department of Biomedical Engineering, Washington University, St. Louis, Missouri 63130, United States
| | - Mark Stopfer
- National Institute of Child Health & Development, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Steve Semancik
- Biochemical Science Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
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48
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Sensory experience selectively regulates transmitter synthesis enzymes in interglomerular circuits. Brain Res 2011; 1382:70-6. [PMID: 21276774 DOI: 10.1016/j.brainres.2011.01.068] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2010] [Revised: 01/19/2011] [Accepted: 01/20/2011] [Indexed: 11/23/2022]
Abstract
Sensory experience influences brain organization and function. A particularly striking example is in the olfactory bulb where reduction of odorant sensory signals profoundly down-regulates dopamine in glomerular neurons. There are two large populations of glomerular inhibitory interneurons: (1) GABAergic periglomerular (PG) cells, whose processes are limited to a single glomerulus, regulate intraglomerular processing and (2) DAergic-GABAergic short axon (SA) cells, whose processes contact multiple glomeruli, regulate interglomerular processing. The inhibitory neurotransmitter GABA is synthesized from L-glutamic acid by the enzyme glutamic acid decarboxylase (GAD) of which there are two major isoforms: GAD65 and GAD67. GAD65 is expressed in uniglomerular PG cells. GAD67 is expressed by SA cells, which also co-express the rate-limiting enzyme for dopamine synthesis, tyrosine hydroxylase (TH). Deafferentation or sensory deprivation decreases TH expression but it is not known if sensory input alters GAD isoforms. Here we report that either deafferentation or reduction of sensory input by nares occlusion significantly reduced GAD67 protein and the number of SA cells expressing GAD67. However, neither manipulation altered GAD65 protein or the number of GAD65 PG cells. These findings show that sensory experience strongly impacts transmitter regulation in the circuit that controls neural processing across glomeruli but not in the circuit that regulates intraglomerular processing.
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49
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Matsutani S. Trajectory and terminal distribution of single centrifugal axons from olfactory cortical areas in the rat olfactory bulb. Neuroscience 2010; 169:436-48. [DOI: 10.1016/j.neuroscience.2010.05.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2010] [Revised: 04/27/2010] [Accepted: 05/01/2010] [Indexed: 11/26/2022]
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Abstract
In many regions of the visual system, the activity of a neuron is normalized by the activity of other neurons in the same region. Here we show that a similar normalization occurs during olfactory processing in the Drosophila antennal lobe. We exploit the orderly anatomy of this circuit to independently manipulate feedforward and lateral input to second-order projection neurons (PNs). Lateral inhibition increases the level of feedforward input needed to drive PNs to saturation, and this normalization scales with the total activity of the olfactory receptor neuron (ORN) population. Increasing total ORN activity also makes PN responses more transient. Strikingly, a model with just two variables (feedforward and total ORN activity) accurately predicts PN odor responses. Finally, we show that discrimination by a linear decoder is facilitated by two complementary transformations: the saturating transformation intrinsic to each processing channel boosts weak signals, while normalization helps equalize responses to different stimuli.
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