1
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Burton SD, Malyshko CM, Urban NN. Fast-spiking interneuron detonation drives high-fidelity inhibition in the olfactory bulb. PLoS Biol 2024; 22:e3002660. [PMID: 39186804 PMCID: PMC11379389 DOI: 10.1371/journal.pbio.3002660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Revised: 09/06/2024] [Accepted: 07/26/2024] [Indexed: 08/28/2024] Open
Abstract
Inhibitory circuits in the mammalian olfactory bulb (OB) dynamically reformat olfactory information as it propagates from peripheral receptors to downstream cortex. To gain mechanistic insight into how specific OB interneuron types support this sensory processing, we examine unitary synaptic interactions between excitatory mitral and tufted cells (MTCs), the OB projection neurons, and a conserved population of anaxonic external plexiform layer interneurons (EPL-INs) using pair and quartet whole-cell recordings in acute mouse brain slices. Physiological, morphological, neurochemical, and synaptic analyses divide EPL-INs into distinct subtypes and reveal that parvalbumin-expressing fast-spiking EPL-INs (FSIs) perisomatically innervate MTCs with release-competent dendrites and synaptically detonate to mediate fast, short-latency recurrent and lateral inhibition. Sparse MTC synchronization supralinearly increases this high-fidelity inhibition, while sensory afferent activation combined with single-cell silencing reveals that individual FSIs account for a substantial fraction of total network-driven MTC lateral inhibition. OB output is thus powerfully shaped by detonation-driven high-fidelity perisomatic inhibition.
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Affiliation(s)
- Shawn D Burton
- Department of Biological Sciences, Lehigh University, Bethlehem, Pennsylvania, United States of America
| | - Christina M Malyshko
- Department of Biological Sciences, Lehigh University, Bethlehem, Pennsylvania, United States of America
| | - Nathaniel N Urban
- Department of Biological Sciences, Lehigh University, Bethlehem, Pennsylvania, United States of America
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2
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Wolf D, Hartig R, Zhuo Y, Scheller MF, Articus M, Moor M, Grinevich V, Linster C, Russo E, Weber-Fahr W, Reinwald JR, Kelsch W. Oxytocin induces the formation of distinctive cortical representations and cognitions biased toward familiar mice. Nat Commun 2024; 15:6274. [PMID: 39054324 PMCID: PMC11272796 DOI: 10.1038/s41467-024-50113-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 06/28/2024] [Indexed: 07/27/2024] Open
Abstract
Social recognition is essential for the formation of social structures. Many times, recognition comes with lesser exploration of familiar animals. This lesser exploration has led to the assumption that recognition may be a habituation memory. The underlying memory mechanisms and the thereby acquired cortical representations of familiar mice have remained largely unknown, however. Here, we introduce an approach directly examining the recognition process from volatile body odors among male mice. We show that volatile body odors emitted by mice are sufficient to identify individuals and that more salience is assigned to familiar mice. Familiarity is encoded by reinforced population responses in two olfactory cortex hubs and communicated to other brain regions. The underlying oxytocin-induced plasticity promotes the separation of the cortical representations of familiar from other mice. In summary, neuronal encoding of familiar animals is distinct and utilizes the cortical representational space more broadly, promoting storage of complex social relationships.
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Affiliation(s)
- David Wolf
- Department of Psychiatry and Psychotherapy, University Medical Center, Johannes Gutenberg University, 55131, Mainz, Germany
- Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, 68159, Mannheim, Germany
| | - Renée Hartig
- Department of Psychiatry and Psychotherapy, University Medical Center, Johannes Gutenberg University, 55131, Mainz, Germany
| | - Yi Zhuo
- Department of Psychiatry and Psychotherapy, University Medical Center, Johannes Gutenberg University, 55131, Mainz, Germany
| | - Max F Scheller
- Department of Psychiatry and Psychotherapy, University Medical Center, Johannes Gutenberg University, 55131, Mainz, Germany
| | - Mirko Articus
- Department of Psychiatry and Psychotherapy, University Medical Center, Johannes Gutenberg University, 55131, Mainz, Germany
- Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, 68159, Mannheim, Germany
| | - Marcel Moor
- Department of Psychiatry and Psychotherapy, University Medical Center, Johannes Gutenberg University, 55131, Mainz, Germany
| | - Valery Grinevich
- Department of Neuropeptide Research in Psychiatry, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, 68159, Mannheim, Germany
| | - Christiane Linster
- Computational Physiology Laboratory, Department of Neurobiology and Behavior, Cornell University, Ithaca, New York, NY, 14850, USA
| | - Eleonora Russo
- Department of Psychiatry and Psychotherapy, University Medical Center, Johannes Gutenberg University, 55131, Mainz, Germany
- The BioRobotics Institute, Department of Excellence in Robotics and AI, Scuola Superiore Sant'Anna, 56127, Pisa, Italy
| | - Wolfgang Weber-Fahr
- Department of Neuroimaging, Translational Imaging, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, 68159, Mannheim, Germany
| | - Jonathan R Reinwald
- Department of Psychiatry and Psychotherapy, University Medical Center, Johannes Gutenberg University, 55131, Mainz, Germany
- Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, 68159, Mannheim, Germany
- Department of Neuroimaging, Translational Imaging, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, 68159, Mannheim, Germany
| | - Wolfgang Kelsch
- Department of Psychiatry and Psychotherapy, University Medical Center, Johannes Gutenberg University, 55131, Mainz, Germany.
- Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, 68159, Mannheim, Germany.
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3
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Chen Z, Padmanabhan K. Adult-neurogenesis allows for representational stability and flexibility in early olfactory system. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.02.601573. [PMID: 39005290 PMCID: PMC11244980 DOI: 10.1101/2024.07.02.601573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
In the early olfactory system, adult-neurogenesis, a process of neuronal replacement results in the continuous reorganization of synaptic connections and network architecture throughout the animal's life. This poses a critical challenge: How does the olfactory system maintain stable representations of odors and therefore allow for stable sensory perceptions amidst this ongoing circuit instability? Utilizing a detailed spiking network model of early olfactory circuits, we uncovered dual roles for adult-neurogenesis: one that both supports representational stability to faithfully encode odor information and also one that facilitates plasticity to allow for learning and adaptation. In the main olfactory bulb, adult-neurogenesis affects neural codes in individual mitral and tufted cells but preserves odor representations at the neuronal population level. By contrast, in the olfactory piriform cortex, both individual cell responses and overall population dynamics undergo progressive changes due to adult-neurogenesis. This leads to representational drift, a gradual alteration in sensory perception. Both processes are dynamic and depend on experience such that repeated exposure to specific odors reduces the drift due to adult-neurogenesis; thus, when the odor environment is stable over the course of adult-neurogenesis, it is neurogenesis that actually allows the representations to remain stable in piriform cortex; when those olfactory environments change, adult-neurogenesis allows the cortical representations to track environmental change. Whereas perceptual stability and plasticity due to learning are often thought of as two distinct, often contradictory processing in neuronal coding, we find that adult-neurogenesis serves as a shared mechanism for both. In this regard, the quixotic presence of adult-neurogenesis in the mammalian olfactory bulb that has been the focus of considerable debate in chemosensory neuroscience may be the mechanistic underpinning behind an array of complex computations.
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Affiliation(s)
- Zhen Chen
- Department of Brain and Cognitive Sciences, University of Rochester, Rochester, NY14627
| | - Krishnan Padmanabhan
- Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642
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4
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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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5
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Burton SD, Malyshko CM, Urban NN. Fast-spiking interneuron detonation drives high-fidelity inhibition in the olfactory bulb. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.07.592874. [PMID: 38766161 PMCID: PMC11100763 DOI: 10.1101/2024.05.07.592874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Inhibitory circuits in the mammalian olfactory bulb (OB) dynamically reformat olfactory information as it propagates from peripheral receptors to downstream cortex. To gain mechanistic insight into how specific OB interneuron types support this sensory processing, we examine unitary synaptic interactions between excitatory mitral and tufted cells (MTCs), the OB projection cells, and a conserved population of anaxonic external plexiform layer interneurons (EPL-INs) using pair and quartet whole-cell recordings in acute mouse brain slices. Physiological, morphological, neurochemical, and synaptic analyses divide EPL-INs into distinct subtypes and reveal that parvalbumin-expressing fast-spiking EPL-INs (FSIs) perisomatically innervate MTCs with release-competent dendrites and synaptically detonate to mediate fast, short-latency recurrent and lateral inhibition. Sparse MTC synchronization supralinearly increases this high-fidelity inhibition, while sensory afferent activation combined with single-cell silencing reveals that individual FSIs account for a substantial fraction of total network-driven MTC lateral inhibition. OB output is thus powerfully shaped by detonation-driven high-fidelity perisomatic inhibition.
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Affiliation(s)
- Shawn D. Burton
- Department of Biological Sciences, Lehigh University, Bethlehem, PA, USA
| | | | - Nathaniel N. Urban
- Department of Biological Sciences, Lehigh University, Bethlehem, PA, USA
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6
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Zak JD, Reddy G, Konanur V, Murthy VN. Distinct information conveyed to the olfactory bulb by feedforward input from the nose and feedback from the cortex. Nat Commun 2024; 15:3268. [PMID: 38627390 PMCID: PMC11021479 DOI: 10.1038/s41467-024-47366-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Accepted: 03/29/2024] [Indexed: 04/19/2024] Open
Abstract
Sensory systems are organized hierarchically, but feedback projections frequently disrupt this order. In the olfactory bulb (OB), cortical feedback projections numerically match sensory inputs. To unravel information carried by these two streams, we imaged the activity of olfactory sensory neurons (OSNs) and cortical axons in the mouse OB using calcium indicators, multiphoton microscopy, and diverse olfactory stimuli. Here, we show that odorant mixtures of increasing complexity evoke progressively denser OSN activity, yet cortical feedback activity is of similar sparsity for all stimuli. Also, representations of complex mixtures are similar in OSNs but are decorrelated in cortical axons. While OSN responses to increasing odorant concentrations exhibit a sigmoidal relationship, cortical axonal responses are complex and nonmonotonic, which can be explained by a model with activity-dependent feedback inhibition in the cortex. Our study indicates that early-stage olfactory circuits have access to local feedforward signals and global, efficiently formatted information about odor scenes through cortical feedback.
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Affiliation(s)
- Joseph D Zak
- Department of Biological Sciences, University of Illinois Chicago, Chicago, IL, 60607, USA.
- Department of Psychology, University of Illinois Chicago, Chicago, IL, 60607, USA.
| | - Gautam Reddy
- Physics & Informatics Laboratories, NTT Research, Inc., Sunnyvale, CA, 94085, USA
- Department of Physics, Princeton University, Princeton, NJ, 08540, USA
- Center for Brain Science, Harvard University, Cambridge, MA, 02138, USA
| | - Vaibhav Konanur
- Department of Biological Sciences, University of Illinois Chicago, Chicago, IL, 60607, USA
| | - Venkatesh N Murthy
- Center for Brain Science, Harvard University, Cambridge, MA, 02138, USA
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, 02138, USA
- Kempner Institute for the Study of Natural and Artificial Intelligence, Harvard University, Allston, 02134, USA
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7
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Mallick A, Dacks AM, Gaudry Q. Olfactory Critical Periods: How Odor Exposure Shapes the Developing Brain in Mice and Flies. BIOLOGY 2024; 13:94. [PMID: 38392312 PMCID: PMC10886215 DOI: 10.3390/biology13020094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 01/26/2024] [Accepted: 01/30/2024] [Indexed: 02/24/2024]
Abstract
Neural networks have an extensive ability to change in response to environmental stimuli. This flexibility peaks during restricted windows of time early in life called critical periods. The ubiquitous occurrence of this form of plasticity across sensory modalities and phyla speaks to the importance of critical periods for proper neural development and function. Extensive investigation into visual critical periods has advanced our knowledge of the molecular events and key processes that underlie the impact of early-life experience on neuronal plasticity. However, despite the importance of olfaction for the overall survival of an organism, the cellular and molecular basis of olfactory critical periods have not garnered extensive study compared to visual critical periods. Recent work providing a comprehensive mapping of the highly organized olfactory neuropil and its development has in turn attracted a growing interest in how these circuits undergo plasticity during critical periods. Here, we perform a comparative review of olfactory critical periods in fruit flies and mice to provide novel insight into the importance of early odor exposure in shaping neural circuits and highlighting mechanisms found across sensory modalities.
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Affiliation(s)
- Ahana Mallick
- Department of Biology, University of Maryland, College Park, MD 20742, USA
| | - Andrew M Dacks
- Department of Biology, West Virginia University, Morgantown, WV 26505, USA
| | - Quentin Gaudry
- Department of Biology, University of Maryland, College Park, MD 20742, USA
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8
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Zavatone-Veth JA, Masset P, Tong WL, Zak JD, Murthy VN, Pehlevan C. Neural Circuits for Fast Poisson Compressed Sensing in the Olfactory Bulb. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.21.545947. [PMID: 37961548 PMCID: PMC10634677 DOI: 10.1101/2023.06.21.545947] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Within a single sniff, the mammalian olfactory system can decode the identity and concentration of odorants wafted on turbulent plumes of air. Yet, it must do so given access only to the noisy, dimensionally-reduced representation of the odor world provided by olfactory receptor neurons. As a result, the olfactory system must solve a compressed sensing problem, relying on the fact that only a handful of the millions of possible odorants are present in a given scene. Inspired by this principle, past works have proposed normative compressed sensing models for olfactory decoding. However, these models have not captured the unique anatomy and physiology of the olfactory bulb, nor have they shown that sensing can be achieved within the 100-millisecond timescale of a single sniff. Here, we propose a rate-based Poisson compressed sensing circuit model for the olfactory bulb. This model maps onto the neuron classes of the olfactory bulb, and recapitulates salient features of their connectivity and physiology. For circuit sizes comparable to the human olfactory bulb, we show that this model can accurately detect tens of odors within the timescale of a single sniff. We also show that this model can perform Bayesian posterior sampling for accurate uncertainty estimation. Fast inference is possible only if the geometry of the neural code is chosen to match receptor properties, yielding a distributed neural code that is not axis-aligned to individual odor identities. Our results illustrate how normative modeling can help us map function onto specific neural circuits to generate new hypotheses.
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Affiliation(s)
- Jacob A Zavatone-Veth
- Center for Brain Science, Harvard University Cambridge, MA 02138
- Department of Physics, Harvard University Cambridge, MA 02138
| | - Paul Masset
- Center for Brain Science, Harvard University Cambridge, MA 02138
- Department of Molecular and Cellular Biology, Harvard University Cambridge, MA 02138
| | - William L Tong
- Center for Brain Science, Harvard University Cambridge, MA 02138
- John A. Paulson School of Engineering and Applied Sciences, Harvard University Cambridge, MA 02138
- Kempner Institute for the Study of Natural and Artificial Intelligence, Harvard University Cambridge, MA 02138
| | - Joseph D Zak
- Department of Biological Sciences, University of Illinois at Chicago Chicago, IL 60607
| | - Venkatesh N Murthy
- Center for Brain Science, Harvard University Cambridge, MA 02138
- Department of Molecular and Cellular Biology, Harvard University Cambridge, MA 02138
| | - Cengiz Pehlevan
- Center for Brain Science, Harvard University Cambridge, MA 02138
- John A. Paulson School of Engineering and Applied Sciences, Harvard University Cambridge, MA 02138
- Kempner Institute for the Study of Natural and Artificial Intelligence, Harvard University Cambridge, MA 02138
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9
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Trejo DH, Ciuparu A, da Silva PG, Velasquez CM, Rebouillat B, Gross MD, Davis MB, Muresan RC, Albeanu DF. Fast updating feedback from piriform cortex to the olfactory bulb relays multimodal reward contingency signals during rule-reversal. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.12.557267. [PMID: 37745564 PMCID: PMC10515864 DOI: 10.1101/2023.09.12.557267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
While animals readily adjust their behavior to adapt to relevant changes in the environment, the neural pathways enabling these changes remain largely unknown. Here, using multiphoton imaging, we investigated whether feedback from the piriform cortex to the olfactory bulb supports such behavioral flexibility. To this end, we engaged head-fixed mice in a multimodal rule-reversal task guided by olfactory and auditory cues. Both odor and, surprisingly, the sound cues triggered cortical bulbar feedback responses which preceded the behavioral report. Responses to the same sensory cue were strongly modulated upon changes in stimulus-reward contingency (rule reversals). The re-shaping of individual bouton responses occurred within seconds of the rule-reversal events and was correlated with changes in the behavior. Optogenetic perturbation of cortical feedback within the bulb disrupted the behavioral performance. Our results indicate that the piriform-to-olfactory bulb feedback carries reward contingency signals and is rapidly re-formatted according to changes in the behavioral context.
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Affiliation(s)
| | - Andrei Ciuparu
- Transylvanian Institute of Neuroscience, Cluj-Napoca, Romania
| | - Pedro Garcia da Silva
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
- current address – Champalimaud Neuroscience Program, Lisbon, Portugal
| | - Cristina M. Velasquez
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
- current address – University of Oxford, UK
| | - Benjamin Rebouillat
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
- current address –École Normale Supérieure, Paris, France
| | | | | | - Raul C. Muresan
- Transylvanian Institute of Neuroscience, Cluj-Napoca, Romania
- STAR-UBB Institute, Babeş-Bolyai University, Cluj-Napoca, Romania
| | - Dinu F. Albeanu
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
- School for Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
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10
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Brunert D, Quintela RM, Rothermel M. The anterior olfactory nucleus revisited - an emerging role for neuropathological conditions? Prog Neurobiol 2023:102486. [PMID: 37343762 DOI: 10.1016/j.pneurobio.2023.102486] [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: 12/23/2022] [Revised: 06/14/2023] [Accepted: 06/16/2023] [Indexed: 06/23/2023]
Abstract
Olfaction is an important sensory modality for many species and greatly influences animal and human behavior. Still, much about olfactory perception remains unknown. The anterior olfactory nucleus is one of the brain's central early olfactory processing areas. Located directly posterior to the olfactory bulb in the olfactory peduncle with extensive in- and output connections and unique cellular composition, it connects olfactory processing centers of the left and right hemispheres. Almost 20 years have passed since the last comprehensive review on the anterior olfactory nucleus has been published and significant advances regarding its anatomy, function, and pathophysiology have been made in the meantime. Here we briefly summarize previous knowledge on the anterior olfactory nucleus, give detailed insights into the progress that has been made in recent years, and map out its emerging importance in translational research of neurological diseases.
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Affiliation(s)
- Daniela Brunert
- Institute of Physiology, Medical Faculty, Otto-von-Guericke-University, 39120 Magdeburg, Germany
| | | | - Markus Rothermel
- Institute of Physiology, Medical Faculty, Otto-von-Guericke-University, 39120 Magdeburg, Germany.
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11
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LaFever BJ, Imamura F. Effects of nasal inflammation on the olfactory bulb. J Neuroinflammation 2022; 19:294. [PMID: 36494744 PMCID: PMC9733073 DOI: 10.1186/s12974-022-02657-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 11/24/2022] [Indexed: 12/13/2022] Open
Abstract
Sinonasal diseases, such as rhinosinusitis, affect up to 12% of individuals each year which constitutes these diseases as some of the most common medical conditions in the world. Exposure to environmental pathogens and toxicants via the nasal cavity can result in a severe inflammatory state commonly observed in these conditions. It is well understood that the epithelial and neuronal cells lining the olfactory mucosa, including olfactory sensory neurons (OSNs), are significantly damaged in these diseases. Prolonged inflammation of the nasal cavity may also lead to hyposmia or anosmia. Although various environmental agents induce inflammation in different ways via distinct cellular and molecular interactions, nasal inflammation has similar consequences on the structure and homeostatic function of the olfactory bulb (OB) which is the first relay center for olfactory information in the brain. Atrophy of the OB occurs via thinning of the superficial OB layers including the olfactory nerve layer, glomerular layer, and superficial external plexiform layer. Intrabulbar circuits of the OB which include connectivity between OB projection neurons, OSNs, and interneurons become significantly dysregulated in which synaptic pruning and dendritic retraction take place. Furthermore, glial cells and other immune cells become hyperactivated and induce a state of inflammation in the OB which results in upregulated cytokine production. Moreover, many of these features of nasal inflammation are present in the case of SARS-CoV-2 infection. This review summarizes the impact of nasal inflammation on the morphological and physiological features of the rodent OB.
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Affiliation(s)
- Brandon J. LaFever
- grid.240473.60000 0004 0543 9901Department of Pharmacology, Penn State College of Medicine, 500 University Dr., Hershey, PA 17033 USA
| | - Fumiaki Imamura
- grid.240473.60000 0004 0543 9901Department of Pharmacology, Penn State College of Medicine, 500 University Dr., Hershey, PA 17033 USA
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12
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Mazo C, Nissant A, Saha S, Peroni E, Lledo PM, Lepousez G. Long-range GABAergic projections contribute to cortical feedback control of sensory processing. Nat Commun 2022; 13:6879. [PMID: 36371430 PMCID: PMC9653434 DOI: 10.1038/s41467-022-34513-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 10/25/2022] [Indexed: 11/15/2022] Open
Abstract
In the olfactory system, the olfactory cortex sends glutamatergic projections back to the first stage of olfactory processing, the olfactory bulb (OB). Such corticofugal excitatory circuits - a canonical circuit motif described in all sensory systems- dynamically adjust early sensory processing. Here, we uncover a corticofugal inhibitory feedback to OB, originating from a subpopulation of GABAergic neurons in the anterior olfactory cortex and innervating both local and output OB neurons. In vivo imaging and network modeling showed that optogenetic activation of cortical GABAergic projections drives a net subtractive inhibition of both spontaneous and odor-evoked activity in local as well as output neurons. In output neurons, stimulation of cortical GABAergic feedback enhances separation of population odor responses in tufted cells, but not mitral cells. Targeted pharmacogenetic silencing of cortical GABAergic axon terminals impaired discrimination of similar odor mixtures. Thus, corticofugal GABAergic projections represent an additional circuit motif in cortical feedback control of sensory processing.
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Affiliation(s)
- Camille Mazo
- Institut Pasteur, Université Paris Cité, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 3571, Perception and Memory Unit, F-75015, Paris, France.
- Champalimaud Foundation, Lisbon, Portugal.
| | - Antoine Nissant
- Institut Pasteur, Université Paris Cité, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 3571, Perception and Memory Unit, F-75015, Paris, France
| | - Soham Saha
- Institut Pasteur, Université Paris Cité, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 3571, Perception and Memory Unit, F-75015, Paris, France
| | - Enzo Peroni
- Institut Pasteur, Université Paris Cité, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 3571, Perception and Memory Unit, F-75015, Paris, France
| | - Pierre-Marie Lledo
- Institut Pasteur, Université Paris Cité, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 3571, Perception and Memory Unit, F-75015, Paris, France.
| | - Gabriel Lepousez
- Institut Pasteur, Université Paris Cité, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 3571, Perception and Memory Unit, F-75015, Paris, France.
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