1
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Naffaa MM. Neurogenesis dynamics in the olfactory bulb: deciphering circuitry organization, function, and adaptive plasticity. Neural Regen Res 2025; 20:1565-1581. [PMID: 38934393 DOI: 10.4103/nrr.nrr-d-24-00312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Accepted: 05/31/2024] [Indexed: 06/28/2024] Open
Abstract
Adult neurogenesis persists after birth in the subventricular zone, with new neurons migrating to the granule cell layer and glomerular layers of the olfactory bulb, where they integrate into existing circuitry as inhibitory interneurons. The generation of these new neurons in the olfactory bulb supports both structural and functional plasticity, aiding in circuit remodeling triggered by memory and learning processes. However, the presence of these neurons, coupled with the cellular diversity within the olfactory bulb, presents an ongoing challenge in understanding its network organization and function. Moreover, the continuous integration of new neurons in the olfactory bulb plays a pivotal role in regulating olfactory information processing. This adaptive process responds to changes in epithelial composition and contributes to the formation of olfactory memories by modulating cellular connectivity within the olfactory bulb and interacting intricately with higher-order brain regions. The role of adult neurogenesis in olfactory bulb functions remains a topic of debate. Nevertheless, the functionality of the olfactory bulb is intricately linked to the organization of granule cells around mitral and tufted cells. This organizational pattern significantly impacts output, network behavior, and synaptic plasticity, which are crucial for olfactory perception and memory. Additionally, this organization is further shaped by axon terminals originating from cortical and subcortical regions. Despite the crucial role of olfactory bulb in brain functions and behaviors related to olfaction, these complex and highly interconnected processes have not been comprehensively studied as a whole. Therefore, this manuscript aims to discuss our current understanding and explore how neural plasticity and olfactory neurogenesis contribute to enhancing the adaptability of the olfactory system. These mechanisms are thought to support olfactory learning and memory, potentially through increased complexity and restructuring of neural network structures, as well as the addition of new granule granule cells that aid in olfactory adaptation. Additionally, the manuscript underscores the importance of employing precise methodologies to elucidate the specific roles of adult neurogenesis amidst conflicting data and varying experimental paradigms. Understanding these processes is essential for gaining insights into the complexities of olfactory function and behavior.
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Affiliation(s)
- Moawiah M Naffaa
- Department of Psychology and Neuroscience, Duke University, Durham, NC, USA
- Department of Cell Biology, Duke University School of Medicine, Durham, NC, USA
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2
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Mihalj D, Bukatova S, Reichova A, Havranek T, Bacova Z, Szeiffova Bacova B, Bakos J. Developmental effects of oxytocin on GABAergic neurons in the olfactory brain regions. Neuroscience 2024; 555:184-193. [PMID: 39094821 DOI: 10.1016/j.neuroscience.2024.07.035] [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: 03/22/2024] [Revised: 07/17/2024] [Accepted: 07/21/2024] [Indexed: 08/04/2024]
Abstract
Oxytocin affects social recognition, interactions, and behavior in adults. Despite growing data on the role of oxytocin in the sensory systems, its effects on early olfactory system development remain poorly understood. The present study aimed to investigate the developmental impact of oxytocin on selected parameters of the GABAergic system in olfactory brain regions. We found a significant increase in the expression of GABAergic markers and scaffolding proteins in the olfactory bulb during the early stages of development in both male and female rats, regardless of oxytocin treatment administered on postnatal days 2 and 3 (P2 and P3, 5 µg/pup). Oxytocin administration markedly reduced the expression of the scaffolding protein Gephyrin in male rats and it led to a significant increase in the number of GABAergic synaptic puncta in the piriform cortex of male rats at P5, P7, and P9. Our data suggest that the developmental action of oxytocin in relation to the GABAergic system may represent a mechanism by which the plasticity and maturation of olfactory brain regions are regulated.
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Affiliation(s)
- Denisa Mihalj
- Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Stanislava Bukatova
- Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Alexandra Reichova
- Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Tomas Havranek
- Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia; Faculty of Medicine, Comenius University, Bratislava, Slovakia
| | - Zuzana Bacova
- Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Barbara Szeiffova Bacova
- Institute for Heart Research, Centre of Experimental Medicine, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Jan Bakos
- Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia; Faculty of Medicine, Comenius University, Bratislava, Slovakia.
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3
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Dejou J, Mandairon N, Didier A. Olfactory neurogenesis plays different parts at successive stages of life, implications for mental health. Front Neural Circuits 2024; 18:1467203. [PMID: 39175668 PMCID: PMC11338910 DOI: 10.3389/fncir.2024.1467203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2024] [Accepted: 07/31/2024] [Indexed: 08/24/2024] Open
Abstract
The olfactory bulb is a unique site of continuous neurogenesis, primarily generating inhibitory interneurons, a process that begins at birth and extends through infancy and adulthood. This review examines the characteristics of olfactory bulb neurogenesis, focusing on granule cells, the most numerous interneurons, and how their age and maturation affect their function. Adult-born granule cells, while immature, contribute to the experience-dependent plasticity of the olfactory circuit by enabling structural and functional synaptic changes. In contrast, granule cells born early in life form the foundational elements of the olfactory bulb circuit, potentially facilitating innate olfactory information processing. The implications of these neonatal cells on early life olfactory memory and their impact on adult perception, particularly in response to aversive events and susceptibility to emotional disorders, warrant further investigation.
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Affiliation(s)
- Jules Dejou
- INSERM, U1028; CNRS, UMR5292; Lyon Neuroscience Research Center, Neuroplasticity and Neuropathology of Olfactory Perception Team, Lyon, France
| | - Nathalie Mandairon
- INSERM, U1028; CNRS, UMR5292; Lyon Neuroscience Research Center, Neuroplasticity and Neuropathology of Olfactory Perception Team, Lyon, France
| | - Anne Didier
- INSERM, U1028; CNRS, UMR5292; Lyon Neuroscience Research Center, Neuroplasticity and Neuropathology of Olfactory Perception Team, Lyon, France
- Institut Universitaire de France, Paris, France
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4
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Sakelaris B, Riecke H. Adult Neurogenesis Reconciles Flexibility and Stability of Olfactory Perceptual Memory. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.03.583153. [PMID: 38737721 PMCID: PMC11087939 DOI: 10.1101/2024.03.03.583153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/14/2024]
Abstract
In brain regions featuring ongoing plasticity, the task of quickly encoding new information without overwriting old memories presents a significant challenge. In the rodent olfactory bulb, which is renowned for substantial structural plasticity driven by adult neurogenesis and persistent turnover of dendritic spines, we show that such plasticity is vital to overcoming this flexibility-stability dilemma. To do so, we develop a computational model for structural plasticity in the olfactory bulb and show that the maturation of adult-born neurons facilitates the abilities to learn quickly and forget slowly. Particularly important to achieve this goal are the transient enhancement of the plasticity, excitability, and susceptibility to apoptosis that characterizes young neurons. The model captures many experimental observations and makes a number of testable predictions. Overall, it identifies memory consolidation as an important role of adult neurogenesis in olfaction and exemplifies how the brain can maintain stable memories despite ongoing extensive plasticity.
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Affiliation(s)
- Bennet Sakelaris
- Engineering Sciences and Applied Mathematics, Northwestern University, Evanston, Illinois, United States of America
| | - Hermann Riecke
- Engineering Sciences and Applied Mathematics, Northwestern University, Evanston, Illinois, United States of America
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Ferreira A, Constantinescu VS, Malvaut S, Saghatelyan A, Hardy SV. Distinct forms of structural plasticity of adult-born interneuron spines in the mouse olfactory bulb induced by different odor learning paradigms. Commun Biol 2024; 7:420. [PMID: 38582915 PMCID: PMC10998910 DOI: 10.1038/s42003-024-06115-7] [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: 07/27/2023] [Accepted: 03/27/2024] [Indexed: 04/08/2024] Open
Abstract
The morpho-functional properties of neural networks constantly adapt in response to environmental stimuli. The olfactory bulb is particularly prone to constant reshaping of neural networks because of ongoing neurogenesis. It remains unclear whether the complexity of distinct odor-induced learning paradigms and sensory stimulation induces different forms of structural plasticity. In the present study, we automatically reconstructed spines in 3D from confocal images and performed unsupervised clustering based on morphometric features. We show that while sensory deprivation decreased the spine density of adult-born neurons without affecting the morphometric properties of these spines, simple and complex odor learning paradigms triggered distinct forms of structural plasticity. A simple odor learning task affected the morphometric properties of the spines, whereas a complex odor learning task induced changes in spine density. Our work reveals distinct forms of structural plasticity in the olfactory bulb tailored to the complexity of odor-learning paradigms and sensory inputs.
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Affiliation(s)
- Aymeric Ferreira
- CERVO Brain Research Center, Quebec City, QC, G1J 2G3, Canada
- Department of Biochemistry, Microbiology, and Bioinformatics, Université Laval, Quebec City, QC, G1V 0A6, Canada
| | - Vlad-Stefan Constantinescu
- CERVO Brain Research Center, Quebec City, QC, G1J 2G3, Canada
- Department of Psychiatry and Neuroscience, Université Laval, Quebec City, QC, G1V 0A6, Canada
| | - Sarah Malvaut
- CERVO Brain Research Center, Quebec City, QC, G1J 2G3, Canada
- Department of Psychiatry and Neuroscience, Université Laval, Quebec City, QC, G1V 0A6, Canada
| | - Armen Saghatelyan
- CERVO Brain Research Center, Quebec City, QC, G1J 2G3, Canada.
- Department of Psychiatry and Neuroscience, Université Laval, Quebec City, QC, G1V 0A6, Canada.
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, K1N 6N5, Canada.
| | - Simon V Hardy
- CERVO Brain Research Center, Quebec City, QC, G1J 2G3, Canada.
- Department of Biochemistry, Microbiology, and Bioinformatics, Université Laval, Quebec City, QC, G1V 0A6, Canada.
- Department of Computer Science and Software Engineering, Université Laval, Quebec City, QC, G1V 0A6, Canada.
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6
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Bao S, Romero JM, Belfort BD, Arenkiel BR. Signaling mechanisms underlying activity-dependent integration of adult-born neurons in the mouse olfactory bulb. Genesis 2024; 62:e23595. [PMID: 38553878 PMCID: PMC10987073 DOI: 10.1002/dvg.23595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 03/18/2024] [Accepted: 03/19/2024] [Indexed: 04/02/2024]
Abstract
Adult neurogenesis has fascinated the field of neuroscience for decades given the prospects of harnessing mechanisms that facilitate the rewiring and/or replacement of adult brain tissue. The subgranular zone of the hippocampus and the subventricular zone of the lateral ventricle are the two main areas in the brain that exhibit ongoing neurogenesis. Of these, adult-born neurons within the olfactory bulb have proven to be a powerful model for studying circuit plasticity, providing a broad and accessible avenue into neuron development, migration, and continued circuit integration within adult brain tissue. This review focuses on some of the recognized molecular and signaling mechanisms underlying activity-dependent adult-born neuron development. Notably, olfactory activity and behavioral states contribute to adult-born neuron plasticity through sensory and centrifugal inputs, in which calcium-dependent transcriptional programs, local translation, and neuropeptide signaling play important roles. This review also highlights areas of needed continued investigation to better understand the remarkable phenomenon of adult-born neuron integration.
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Affiliation(s)
- Suyang Bao
- Development, Disease Models, and Therapeutics Graduate Program, Baylor College of Medicine, Houston, Texas 77030, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, Texas 77030, USA
| | - Juan M. Romero
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, Texas 77030, USA
- Medical Scientist Training Program, Baylor College of Medicine, Houston, Texas 77030, USA
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Benjamin D.W. Belfort
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, Texas 77030, USA
- Medical Scientist Training Program, Baylor College of Medicine, Houston, Texas 77030, USA
- Genetics and Genomics Graduate Program, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Benjamin R. Arenkiel
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, Texas 77030, USA
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030, USA
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7
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Srinivasan S, Daste S, Modi MN, Turner GC, Fleischmann A, Navlakha S. Effects of stochastic coding on olfactory discrimination in flies and mice. PLoS Biol 2023; 21:e3002206. [PMID: 37906721 PMCID: PMC10618007 DOI: 10.1371/journal.pbio.3002206] [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] [Received: 03/21/2022] [Accepted: 08/21/2023] [Indexed: 11/02/2023] Open
Abstract
Sparse coding can improve discrimination of sensory stimuli by reducing overlap between their representations. Two factors, however, can offset sparse coding's benefits: similar sensory stimuli have significant overlap and responses vary across trials. To elucidate the effects of these 2 factors, we analyzed odor responses in the fly and mouse olfactory regions implicated in learning and discrimination-the mushroom body (MB) and the piriform cortex (PCx). We found that neuronal responses fall along a continuum from extremely reliable across trials to extremely variable or stochastic. Computationally, we show that the observed variability arises from noise within central circuits rather than sensory noise. We propose this coding scheme to be advantageous for coarse- and fine-odor discrimination. More reliable cells enable quick discrimination between dissimilar odors. For similar odors, however, these cells overlap and do not provide distinguishing information. By contrast, more unreliable cells are decorrelated for similar odors, providing distinguishing information, though these benefits only accrue with extended training with more trials. Overall, we have uncovered a conserved, stochastic coding scheme in vertebrates and invertebrates, and we identify a candidate mechanism, based on variability in a winner-take-all (WTA) inhibitory circuit, that improves discrimination with training.
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Affiliation(s)
- Shyam Srinivasan
- Kavli Institute for Brain and Mind, University of California, San Diego, California, United States of America
- Salk Institute for Biological Studies, La Jolla, California, United States of America
| | - Simon Daste
- Department of Neuroscience, Division of Biology and Medicine, Brown University, Providence, Rhode Island, United States of America
- Robert J. and Nancy D. Carney Institute for Brain Science, Brown University, Providence, Rhode Island, United States of America
| | - Mehrab N. Modi
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, United States of America
| | - Glenn C. Turner
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, United States of America
| | - Alexander Fleischmann
- Department of Neuroscience, Division of Biology and Medicine, Brown University, Providence, Rhode Island, United States of America
- Robert J. and Nancy D. Carney Institute for Brain Science, Brown University, Providence, Rhode Island, United States of America
| | - Saket Navlakha
- Simons Center for Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, United States of America
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8
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Su X, Kovalchuk Y, Mojtahedi N, Kamari F, Claassen M, Garaschuk O. Neuronal silence as a prosurvival factor for adult-born olfactory bulb interneurons. Stem Cell Reports 2023; 18:1182-1195. [PMID: 37116486 DOI: 10.1016/j.stemcr.2023.03.018] [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: 09/13/2022] [Revised: 03/29/2023] [Accepted: 03/29/2023] [Indexed: 04/30/2023] Open
Abstract
Adult-born cells, arriving daily into the rodent olfactory bulb, either integrate into the neural circuitry or get eliminated. However, whether these two populations differ in their morphological or functional properties remains unclear. Using longitudinal in vivo two-photon imaging, we monitored dendritic morphogenesis, odor-evoked responsiveness, ongoing Ca2+ signaling, and survival/death of adult-born juxtaglomerular neurons (abJGNs). We found that the maturation of abJGNs is accompanied by a significant reduction in dendritic complexity, with surviving and subsequently eliminated cells showing similar degrees of dendritic remodeling. Surprisingly, ∼63% of eliminated abJGNs acquired odor responsiveness before death, with amplitudes and time courses of odor-evoked responses similar to those recorded in surviving cells. However, the subsequently eliminated cell population exhibited significantly higher ongoing Ca2+ signals, with a difference visible even 10 days before death. Quantitative supervised machine learning analysis revealed a relationship between the abJGNs' activity and survival probability, with low neuronal activity being supportive for survival.
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Affiliation(s)
- Xin Su
- Department of Neurophysiology, Institute of Physiology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Yury Kovalchuk
- Department of Neurophysiology, Institute of Physiology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Nima Mojtahedi
- Department of Neurophysiology, Institute of Physiology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Farzin Kamari
- Department of Neurophysiology, Institute of Physiology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Manfred Claassen
- Department of Internal Medicine I, University Hospital Tübingen, Tübingen, Germany; Department of Computer Science, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Olga Garaschuk
- Department of Neurophysiology, Institute of Physiology, Eberhard Karls University of Tübingen, Tübingen, Germany.
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9
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Zuk KE, Cansler HL, Wang J, Meeks JP. Arc-Expressing Accessory Olfactory Bulb Interneurons Support Chemosensory Social Behavioral Plasticity. J Neurosci 2023; 43:1178-1190. [PMID: 36623874 PMCID: PMC9962775 DOI: 10.1523/jneurosci.0847-22.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 11/18/2022] [Accepted: 11/22/2022] [Indexed: 01/11/2023] Open
Abstract
The accessory olfactory system (AOS) is critical for the development and expression of social behavior. The first dedicated circuit in the AOS, the accessory olfactory bulb (AOB), exhibits cellular and network plasticity in male and female mice after social experience. In the AOB, interneurons called internal granule cells (IGCs) express the plasticity-associated immediate-early gene Arc following intermale aggression or mating. Here, we sought to better understand how Arc-expressing IGCs shape AOB information processing and social behavior in the context of territorial aggression. We used "ArcTRAP" (Arc-CreERT2) transgenic mice to selectively and permanently label Arc-expressing IGCs following male-male resident-intruder interactions. Using whole-cell patch-clamp electrophysiology, we found that Arc-expressing IGCs display increased intrinsic excitability for several days after a single resident-intruder interaction. Further, we found that Arc-expressing IGCs maintain this increased excitability across repeated resident-intruder interactions, during which resident mice increase or "ramp" their aggression. We tested the hypothesis that Arc-expressing IGCs participate in ramping aggression. Using a combination of ArcTRAP mice and chemogenetics (Cre-dependent hM4D(Gi)-mCherry AAV injections), we found that disruption of Arc-expressing IGC activity during repeated resident-intruder interactions abolishes the ramping aggression exhibited by resident male mice. This work shows that Arc-expressing AOB IGC ensembles are activated by specific chemosensory environments, and play an integral role in the establishment and expression of sex-typical social behavior. These studies identify a population of plastic interneurons in an early chemosensory circuit that display physiological features consistent with simple memory formation, increasing our understanding of central chemosensory processing and mammalian social behavior.SIGNIFICANCE STATEMENT The accessory olfactory system plays a vital role in rodent chemosensory social behavior. We studied experience-dependent plasticity in the accessory olfactory bulb and found that internal granule cells expressing the immediate-early gene Arc after the resident-intruder paradigm increase their excitability for several days. We investigated the roles of these Arc-expressing internal granule cells on chemosensory social behavior by chemogenetically manipulating their excitability during repeated social interactions. We found that inhibiting these cells eliminated intermale aggressive ramping behavior. These studies identify a population of plastic interneurons in an early chemosensory circuit that display physiological features consistent with simple memory formation, increasing our understanding of central chemosensory processing and mammalian social behavior.
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Affiliation(s)
- Kelsey E Zuk
- Neuroscience Graduate Program, University of Texas Southwestern Medical Center, Dallas, Texas 75390
- Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642
| | - Hillary L Cansler
- Department of Pharmacology, University of Florida College of Medicine, Gainesville, Florida 32603
| | - Jinxin Wang
- Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642
| | - Julian P Meeks
- Department of Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642
- Department of Pediatrics, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642
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10
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Shani-Narkiss H, Beniaguev D, Segev I, Mizrahi A. Stability and flexibility of odor representations in the mouse olfactory bulb. Front Neural Circuits 2023; 17:1157259. [PMID: 37151358 PMCID: PMC10157098 DOI: 10.3389/fncir.2023.1157259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 03/27/2023] [Indexed: 05/09/2023] Open
Abstract
Dynamic changes in sensory representations have been basic tenants of studies in neural coding and plasticity. In olfaction, relatively little is known about the dynamic range of changes in odor representations under different brain states and over time. Here, we used time-lapse in vivo two-photon calcium imaging to describe changes in odor representation by mitral cells, the output neurons of the mouse olfactory bulb. Using anesthetics as a gross manipulation to switch between different brain states (wakefulness and under anesthesia), we found that odor representations by mitral cells undergo significant re-shaping across states but not over time within state. Odor representations were well balanced across the population in the awake state yet highly diverse under anesthesia. To evaluate differences in odor representation across states, we used linear classifiers to decode odor identity in one state based on training data from the other state. Decoding across states resulted in nearly chance-level accuracy. In contrast, repeating the same procedure for data recorded within the same state but in different time points, showed that time had a rather minor impact on odor representations. Relative to the differences across states, odor representations remained stable over months. Thus, single mitral cells can change dynamically across states but maintain robust representations across months. These findings have implications for sensory coding and plasticity in the mammalian brain.
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Affiliation(s)
- Haran Shani-Narkiss
- The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - David Beniaguev
- The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Idan Segev
- The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
- Department of Neurobiology, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Adi Mizrahi
- The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
- Department of Neurobiology, The Hebrew University of Jerusalem, Jerusalem, Israel
- *Correspondence: Adi Mizrahi,
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11
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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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12
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Meng JH, Riecke H. Structural spine plasticity: Learning and forgetting of odor-specific subnetworks in the olfactory bulb. PLoS Comput Biol 2022; 18:e1010338. [PMID: 36279303 PMCID: PMC9632792 DOI: 10.1371/journal.pcbi.1010338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 11/03/2022] [Accepted: 09/28/2022] [Indexed: 11/05/2022] Open
Abstract
Learning to discriminate between different sensory stimuli is essential for survival. In rodents, the olfactory bulb, which contributes to odor discrimination via pattern separation, exhibits extensive structural synaptic plasticity involving the formation and removal of synaptic spines, even in adult animals. The network connectivity resulting from this plasticity is still poorly understood. To gain insight into this connectivity we present here a computational model for the structural plasticity of the reciprocal synapses between the dominant population of excitatory principal neurons and inhibitory interneurons. It incorporates the observed modulation of spine stability by odor exposure. The model captures the striking experimental observation that the exposure to odors does not always enhance their discriminability: while training with similar odors enhanced their discriminability, training with dissimilar odors actually reduced the discriminability of the training stimuli. Strikingly, this differential learning does not require the activity-dependence of the spine stability and occurs also in a model with purely random spine dynamics in which the spine density is changed homogeneously, e.g., due to a global signal. However, the experimentally observed odor-specific reduction in the response of principal cells as a result of extended odor exposure and the concurrent disinhibition of a subset of principal cells arise only in the activity-dependent model. Moreover, this model predicts the experimentally testable recovery of odor response through weak but not through strong odor re-exposure and the forgetting of odors via exposure to interfering odors. Combined with the experimental observations, the computational model provides strong support for the prediction that odor exposure leads to the formation of odor-specific subnetworks in the olfactory bulb. A key feature of the brain is its ability to learn through the plasticity of its network. The olfactory bulb in the olfactory system is a remarkable brain area whose anatomical structure evolves substantially still in adult animals by establishing new synaptic connections and removing existing ones. We present a computational model for this process and employ it to interpret recent experimental results. By comparing the results of our model with those of a random control model we identify various experimental observations that lend strong support to the notion that the network of the olfactory bulb comprises learned, odor-specific subnetworks. Moreover, our model explains the recent observation that the learning of odors does not always improve their discriminability and provides testable predictions for the recovery of odor response after repeated odor exposure and for when the learning of new odors interferes with retaining the memory of familiar odors.
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Affiliation(s)
- John Hongyu Meng
- Engineering Sciences and Applied Mathematics, Northwestern University, Evanston, Illinois, United States of America
| | - Hermann Riecke
- Engineering Sciences and Applied Mathematics, Northwestern University, Evanston, Illinois, United States of America
- * E-mail:
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13
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Aghvami SS, Kubota Y, Egger V. Anatomical and Functional Connectivity at the Dendrodendritic Reciprocal Mitral Cell-Granule Cell Synapse: Impact on Recurrent and Lateral Inhibition. Front Neural Circuits 2022; 16:933201. [PMID: 35937203 PMCID: PMC9355734 DOI: 10.3389/fncir.2022.933201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Accepted: 05/27/2022] [Indexed: 11/16/2022] Open
Abstract
In the vertebrate olfactory bulb, reciprocal dendrodendritic interactions between its principal neurons, the mitral and tufted cells, and inhibitory interneurons in the external plexiform layer mediate both recurrent and lateral inhibition, with the most numerous of these interneurons being granule cells. Here, we used recently established anatomical parameters and functional data on unitary synaptic transmission to simulate the strength of recurrent inhibition of mitral cells specifically from the reciprocal spines of rat olfactory bulb granule cells in a quantitative manner. Our functional data allowed us to derive a unitary synaptic conductance on the order of 0.2 nS. The simulations predicted that somatic voltage deflections by even proximal individual granule cell inputs are below the detection threshold and that attenuation with distance is roughly linear, with a passive length constant of 650 μm. However, since recurrent inhibition in the wake of a mitral cell action potential will originate from hundreds of reciprocal spines, the summated recurrent IPSP will be much larger, even though there will be substantial mutual shunting across the many inputs. Next, we updated and refined a preexisting model of connectivity within the entire rat olfactory bulb, first between pairs of mitral and granule cells, to estimate the likelihood and impact of recurrent inhibition depending on the distance between cells. Moreover, to characterize the substrate of lateral inhibition, we estimated the connectivity via granule cells between any two mitral cells or all the mitral cells that belong to a functional glomerular ensemble (i.e., which receive their input from the same glomerulus), again as a function of the distance between mitral cells and/or entire glomerular mitral cell ensembles. Our results predict the extent of the three regimes of anatomical connectivity between glomerular ensembles: high connectivity within a glomerular ensemble and across the first four rings of adjacent glomeruli, substantial connectivity to up to eleven glomeruli away, and negligible connectivity beyond. Finally, in a first attempt to estimate the functional strength of granule-cell mediated lateral inhibition, we combined this anatomical estimate with our above simulation results on attenuation with distance, resulting in slightly narrowed regimes of a functional impact compared to the anatomical connectivity.
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Affiliation(s)
- S. Sara Aghvami
- School of Cognitive Sciences, Institute for Research in Fundamental Sciences (IPM), Tehran, Iran
| | - Yoshiyuki Kubota
- Division of Cerebral Circuitry, National Institute for Physiological Sciences (NIPS), Okazaki, Japan
| | - Veronica Egger
- Neurophysiology, Institute of Zoology, Regensburg University, Regensburg, Germany
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14
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Baklaushev VP, Yusubalieva GM, Samoilova EM, Belopasov VV. Resident Neural Stem Cell Niches and Regeneration: The Splendors and Miseries of Adult Neurogenesis. Russ J Dev Biol 2022. [DOI: 10.1134/s1062360422030080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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15
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Kurematsu C, Sawada M, Ohmuraya M, Tanaka M, Kuboyama K, Ogino T, Matsumoto M, Oishi H, Inada H, Ishido Y, Sakakibara Y, Nguyen HB, Thai TQ, Kohsaka S, Ohno N, Yamada MK, Asai M, Sokabe M, Nabekura J, Asano K, Tanaka M, Sawamoto K. Synaptic pruning of murine adult-born neurons by microglia depends on phosphatidylserine. J Exp Med 2022; 219:213073. [PMID: 35297954 PMCID: PMC9195048 DOI: 10.1084/jem.20202304] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Revised: 08/13/2021] [Accepted: 11/30/2021] [Indexed: 12/21/2022] Open
Abstract
New neurons, continuously added in the adult olfactory bulb (OB) and hippocampus, are involved in information processing in neural circuits. Here, we show that synaptic pruning of adult-born neurons by microglia depends on phosphatidylserine (PS), whose exposure on dendritic spines is inversely correlated with their input activity. To study the role of PS in spine pruning by microglia in vivo, we developed an inducible transgenic mouse line, in which the exposed PS is masked by a dominant-negative form of milk fat globule-EGF-factor 8 (MFG-E8), MFG-E8D89E. In this transgenic mouse, the spine pruning of adult-born neurons by microglia is impaired in the OB and hippocampus. Furthermore, the electrophysiological properties of these adult-born neurons are altered in MFG-E8D89E mice. These data suggest that PS is involved in the microglial spine pruning and the functional maturation of adult-born neurons. The MFG-E8D89E-based genetic approach shown in this study has broad applications for understanding the biology of PS-mediated phagocytosis in vivo.
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Affiliation(s)
- Chihiro Kurematsu
- Department of Developmental and Regenerative Neurobiology, Institute of Brain Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Masato Sawada
- Department of Developmental and Regenerative Neurobiology, Institute of Brain Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.,Division of Neural Development and Regeneration, National Institute for Physiological Sciences, Okazaki, Japan
| | - Masaki Ohmuraya
- Department of Genetics, Hyogo College of Medicine, Nishinomiya, Japan
| | - Motoki Tanaka
- Department of Disease Model, Institute for Developmental Research, Aichi Developmental Disability Center, Kasugai, Japan
| | - Kazuya Kuboyama
- Department of Developmental and Regenerative Neurobiology, Institute of Brain Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Takashi Ogino
- Department of Developmental and Regenerative Neurobiology, Institute of Brain Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Mami Matsumoto
- Department of Developmental and Regenerative Neurobiology, Institute of Brain Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.,Section of Electron Microscopy, Supportive Center for Brain Research, National Institute for Physiological Sciences, Okazaki, Japan
| | - Hisashi Oishi
- Department of Comparative and Experimental Medicine, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Hiroyuki Inada
- Division of Homeostatic Development, National Institute for Physiological Sciences, Okazaki, Japan
| | - Yuri Ishido
- Department of Developmental and Regenerative Neurobiology, Institute of Brain Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Yukina Sakakibara
- Department of Developmental and Regenerative Neurobiology, Institute of Brain Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Huy Bang Nguyen
- Section of Electron Microscopy, Supportive Center for Brain Research, National Institute for Physiological Sciences, Okazaki, Japan.,Department of Anatomy, Faculty of Medicine, University of Medicine and Pharmacy at Ho Chi Minh City, Ho Chi Minh City, Vietnam
| | - Truc Quynh Thai
- Section of Electron Microscopy, Supportive Center for Brain Research, National Institute for Physiological Sciences, Okazaki, Japan.,Department of Histology-Embryology-Genetics, Faculty of Basic Medical Sciences, Pham Ngoc Thach University of Medicine, Ho Chi Minh City, Vietnam
| | - Shinichi Kohsaka
- National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Japan
| | - Nobuhiko Ohno
- Department of Anatomy, Division of Histology and Cell Biology, Jichi Medical University, School of Medicine, Shimotsuke, Japan.,Division of Ultrastructural Research, National Institute for Physiological Sciences, Okazaki, Japan
| | - Maki K Yamada
- Department of Neuropharmacology, Kagawa School of Pharmaceutical Sciences and Institute of Neuroscience, Tokushima Bunri University, Sanuki, Japan
| | - Masato Asai
- Department of Disease Model, Institute for Developmental Research, Aichi Developmental Disability Center, Kasugai, Japan
| | - Masahiro Sokabe
- Mechanobiology Laboratory, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Junichi Nabekura
- Division of Homeostatic Development, National Institute for Physiological Sciences, Okazaki, Japan
| | - Kenichi Asano
- Laboratory of Immune Regulation, Tokyo University of Pharmacy and Life Sciences, Hachioji, Japan
| | - Masato Tanaka
- Laboratory of Immune Regulation, Tokyo University of Pharmacy and Life Sciences, Hachioji, Japan
| | - Kazunobu Sawamoto
- Department of Developmental and Regenerative Neurobiology, Institute of Brain Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.,Division of Neural Development and Regeneration, National Institute for Physiological Sciences, Okazaki, Japan
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16
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Chen Z, Padmanabhan K. Top-down feedback enables flexible coding strategies in the olfactory cortex. Cell Rep 2022; 38:110545. [PMID: 35320723 DOI: 10.1016/j.celrep.2022.110545] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 12/30/2021] [Accepted: 03/01/2022] [Indexed: 11/03/2022] Open
Abstract
In chemical sensation, multiple models have been proposed to explain how odors are represented in the olfactory cortex. One hypothesis is that the combinatorial identity of active neurons within sniff-related time windows is critical, whereas another model proposes that it is the temporal structure of neural activity that is essential for encoding odor information. We find that top-down feedback to the main olfactory bulb dictates the information transmitted to the piriform cortex and switches between these coding strategies. Using a detailed network model, we demonstrate that feedback control of inhibition influences the excitation-inhibition balance in mitral cells, restructuring the dynamics of piriform cortical cells. This results in performance improvement in odor discrimination tasks. These findings present a framework for early olfactory computation, where top-down feedback to the bulb flexibly shapes the temporal structure of neural activity in the piriform cortex, allowing the early olfactory system to dynamically switch between two distinct coding models.
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Affiliation(s)
- Zhen Chen
- Department of Brain and Cognitive Sciences, University of Rochester, Rochester, NY 14627, USA
| | - Krishnan Padmanabhan
- Department of Neuroscience, Neuroscience Graduate Program, Del Monte Institute for Neuroscience, Center for Visual Sciences, Intellectual and Developmental Disability Research Center, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA.
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17
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12 months is a pivotal age for olfactory perceptual learning and its underlying neuronal plasticity in aging mice. Neurobiol Aging 2022; 114:73-83. [DOI: 10.1016/j.neurobiolaging.2022.03.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 03/04/2022] [Accepted: 03/06/2022] [Indexed: 11/23/2022]
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18
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Sailor KA, Agoranos G, López-Manzaneda S, Tada S, Gillet-Legrand B, Guerinot C, Masson JB, Vestergaard CL, Bonner M, Gagnidze K, Veres G, Lledo PM, Cartier N. Hematopoietic stem cell transplantation chemotherapy causes microglia senescence and peripheral macrophage engraftment in the brain. Nat Med 2022; 28:517-527. [DOI: 10.1038/s41591-022-01691-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 01/10/2022] [Indexed: 02/07/2023]
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19
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Kersen DEC, Tavoni G, Balasubramanian V. Connectivity and dynamics in the olfactory bulb. PLoS Comput Biol 2022; 18:e1009856. [PMID: 35130267 PMCID: PMC8853646 DOI: 10.1371/journal.pcbi.1009856] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 02/17/2022] [Accepted: 01/22/2022] [Indexed: 12/22/2022] Open
Abstract
Dendrodendritic interactions between excitatory mitral cells and inhibitory granule cells in the olfactory bulb create a dense interaction network, reorganizing sensory representations of odors and, consequently, perception. Large-scale computational models are needed for revealing how the collective behavior of this network emerges from its global architecture. We propose an approach where we summarize anatomical information through dendritic geometry and density distributions which we use to calculate the connection probability between mitral and granule cells, while capturing activity patterns of each cell type in the neural dynamical systems theory of Izhikevich. In this way, we generate an efficient, anatomically and physiologically realistic large-scale model of the olfactory bulb network. Our model reproduces known connectivity between sister vs. non-sister mitral cells; measured patterns of lateral inhibition; and theta, beta, and gamma oscillations. The model in turn predicts testable relationships between network structure and several functional properties, including lateral inhibition, odor pattern decorrelation, and LFP oscillation frequency. We use the model to explore the influence of cortex on the olfactory bulb, demonstrating possible mechanisms by which cortical feedback to mitral cells or granule cells can influence bulbar activity, as well as how neurogenesis can improve bulbar decorrelation without requiring cell death. Our methodology provides a tractable tool for other researchers.
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Affiliation(s)
- David E. Chen Kersen
- Computational Neuroscience Initiative, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Gaia Tavoni
- Computational Neuroscience Initiative, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- Department of Neuroscience, Washington University in St. Louis, St. Louis, Missouri, United States of America
| | - Vijay Balasubramanian
- Computational Neuroscience Initiative, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- Department of Neuroscience, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
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20
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Sankar R, Rougier NP, Leblois A. Computational benefits of structural plasticity, illustrated in songbirds. Neurosci Biobehav Rev 2021; 132:1183-1196. [PMID: 34801257 DOI: 10.1016/j.neubiorev.2021.10.033] [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: 06/16/2021] [Revised: 10/13/2021] [Accepted: 10/25/2021] [Indexed: 11/29/2022]
Abstract
The plasticity of nervous systems allows animals to quickly adapt to a changing environment. In particular, the structural plasticity of brain networks is often critical to the development of the central nervous system and the acquisition of complex behaviors. As an example, structural plasticity is central to the development of song-related brain circuits and may be critical for song acquisition in juvenile songbirds. Here, we review current evidences for structural plasticity and their significance from a computational point of view. We start by reviewing evidence for structural plasticity across species and categorizing them along the spatial axes as well as the along the time course during development. We introduce the vocal learning circuitry in zebra finches, as a useful example of structural plasticity, and use this specific case to explore the possible contributions of structural plasticity to computational models. Finally, we discuss current modeling studies incorporating structural plasticity and unexplored questions which are raised by such models.
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Affiliation(s)
- Remya Sankar
- Inria Bordeaux Sud-Ouest, Talence, France; Institut des Maladies Neurodégénératives, Université de Bordeaux, Bordeaux, France; Institut des Maladies Neurodégénératives, CNRS, UMR 5293, France; LaBRI, Université de Bordeaux, INP, CNRS, UMR 5800, Talence, France
| | - Nicolas P Rougier
- Inria Bordeaux Sud-Ouest, Talence, France; Institut des Maladies Neurodégénératives, Université de Bordeaux, Bordeaux, France; Institut des Maladies Neurodégénératives, CNRS, UMR 5293, France; LaBRI, Université de Bordeaux, INP, CNRS, UMR 5800, Talence, France
| | - Arthur Leblois
- Institut des Maladies Neurodégénératives, Université de Bordeaux, Bordeaux, France; Institut des Maladies Neurodégénératives, CNRS, UMR 5293, France.
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21
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Tavoni G, Kersen DEC, Balasubramanian V. Cortical feedback and gating in odor discrimination and generalization. PLoS Comput Biol 2021; 17:e1009479. [PMID: 34634035 PMCID: PMC8530364 DOI: 10.1371/journal.pcbi.1009479] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Revised: 10/21/2021] [Accepted: 09/24/2021] [Indexed: 11/30/2022] Open
Abstract
A central question in neuroscience is how context changes perception. In the olfactory system, for example, experiments show that task demands can drive divergence and convergence of cortical odor responses, likely underpinning olfactory discrimination and generalization. Here, we propose a simple statistical mechanism for this effect based on unstructured feedback from the central brain to the olfactory bulb, which represents the context associated with an odor, and sufficiently selective cortical gating of sensory inputs. Strikingly, the model predicts that both convergence and divergence of cortical odor patterns should increase when odors are initially more similar, an effect reported in recent experiments. The theory in turn predicts reversals of these trends following experimental manipulations and in neurological conditions that increase cortical excitability.
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Affiliation(s)
- Gaia Tavoni
- Computational Neuroscience Initiative, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- Department of Neuroscience, Washington University in St. Louis, St. Louis, Missouri, United States of America
| | - David E. Chen Kersen
- Computational Neuroscience Initiative, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Vijay Balasubramanian
- Computational Neuroscience Initiative, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- Department of Neuroscience, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
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22
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Gribaudo S, Saraulli D, Nato G, Bonzano S, Gambarotta G, Luzzati F, Costanzi M, Peretto P, Bovetti S, De Marchis S. Neurogranin Regulates Adult-Born Olfactory Granule Cell Spine Density and Odor-Reward Associative Memory in Mice. Int J Mol Sci 2021; 22:ijms22084269. [PMID: 33924098 PMCID: PMC8074334 DOI: 10.3390/ijms22084269] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 04/14/2021] [Accepted: 04/16/2021] [Indexed: 11/16/2022] Open
Abstract
Neurogranin (Ng) is a brain-specific postsynaptic protein, whose role in modulating Ca2+/calmodulin signaling in glutamatergic neurons has been linked to enhancement in synaptic plasticity and cognitive functions. Accordingly, Ng knock-out (Ng-ko) mice display hippocampal-dependent learning and memory impairments associated with a deficit in long-term potentiation induction. In the adult olfactory bulb (OB), Ng is expressed by a large population of GABAergic granule cells (GCs) that are continuously generated during adult life, undergo high synaptic remodeling in response to the sensory context, and play a key role in odor processing. However, the possible implication of Ng in OB plasticity and function is yet to be investigated. Here, we show that Ng expression in the OB is associated with the mature state of adult-born GCs, where its active-phosphorylated form is concentrated at post-synaptic sites. Constitutive loss of Ng in Ng-ko mice resulted in defective spine density in adult-born GCs, while their survival remained unaltered. Moreover, Ng-ko mice show an impaired odor-reward associative memory coupled with reduced expression of the activity-dependent transcription factor Zif268 in olfactory GCs. Overall, our data support a role for Ng in the molecular mechanisms underlying GC plasticity and the formation of olfactory associative memory.
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Affiliation(s)
- Simona Gribaudo
- Department of Life Sciences and Systems Biology (DBIOS), University of Torino, 10123 Turin, Italy; (S.G.); (G.N.); (S.B.); (F.L.); (P.P.)
| | - Daniele Saraulli
- Institute of Cell Biology and Neurobiology (IBCN), National Research Council, 00143 Rome, Italy;
| | - Giulia Nato
- Department of Life Sciences and Systems Biology (DBIOS), University of Torino, 10123 Turin, Italy; (S.G.); (G.N.); (S.B.); (F.L.); (P.P.)
- Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, 10043 Turin, Italy;
| | - Sara Bonzano
- Department of Life Sciences and Systems Biology (DBIOS), University of Torino, 10123 Turin, Italy; (S.G.); (G.N.); (S.B.); (F.L.); (P.P.)
- Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, 10043 Turin, Italy;
| | - Giovanna Gambarotta
- Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, 10043 Turin, Italy;
- Department of Clinical and Biological Sciences (DSCB), University of Torino, 10043 Turin, Italy
| | - Federico Luzzati
- Department of Life Sciences and Systems Biology (DBIOS), University of Torino, 10123 Turin, Italy; (S.G.); (G.N.); (S.B.); (F.L.); (P.P.)
- Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, 10043 Turin, Italy;
| | - Marco Costanzi
- Department of Human Sciences, LUMSA University, 00193 Rome, Italy;
| | - Paolo Peretto
- Department of Life Sciences and Systems Biology (DBIOS), University of Torino, 10123 Turin, Italy; (S.G.); (G.N.); (S.B.); (F.L.); (P.P.)
- Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, 10043 Turin, Italy;
| | - Serena Bovetti
- Department of Life Sciences and Systems Biology (DBIOS), University of Torino, 10123 Turin, Italy; (S.G.); (G.N.); (S.B.); (F.L.); (P.P.)
- Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, 10043 Turin, Italy;
- Correspondence: (S.B.); (S.D.M.)
| | - Silvia De Marchis
- Department of Life Sciences and Systems Biology (DBIOS), University of Torino, 10123 Turin, Italy; (S.G.); (G.N.); (S.B.); (F.L.); (P.P.)
- Neuroscience Institute Cavalieri Ottolenghi (NICO), Orbassano, 10043 Turin, Italy;
- Correspondence: (S.B.); (S.D.M.)
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23
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Egger V, Kuner T. Olfactory bulb granule cells: specialized to link coactive glomerular columns for percept generation and discrimination of odors. Cell Tissue Res 2021; 383:495-506. [PMID: 33404844 PMCID: PMC7873091 DOI: 10.1007/s00441-020-03402-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 12/14/2020] [Indexed: 12/16/2022]
Abstract
The role of granule cells in olfactory processing is surrounded by several enigmatic observations, such as the purpose of reciprocal spines and the mechanisms for GABA release, the apparently low firing activity and recurrent inhibitory drive of granule cells, the missing proof for functional reciprocal connectivity, and the apparently negligible contribution to lateral inhibition. Here, we summarize recent results with regard to both the mechanisms of GABA release and the behavioral relevance of granule cell activity during odor discrimination. We outline a novel hypothesis that has the potential to resolve most of these enigmas and allows further predictions on the function of granule cells in odor processing. Briefly, recent findings imply that GABA release from the reciprocal spine requires a local spine action potential and the cooperative action of NMDA receptors and high voltage-activated Ca2+ channels. Thus, lateral inhibition is conditional on activity in the principal neurons connected to a granule cell and tightly intertwined with recurrent inhibition. This notion allows us to infer that lateral inhibition between principal neurons occurs "on demand," i.e., selectively on coactive mitral and tufted cells, and thus can provide directed, dynamically switched lateral inhibition in a sensory system with 1000 input channels organized in glomerular columns. The mechanistic underpinnings of this hypothesis concur with findings from odor discrimination behavior in mice with synaptic proteins deleted in granule cells. In summary, our hypothesis explains the unusual microcircuit of the granule cell reciprocal spine as a means of olfactory combinatorial coding.
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Affiliation(s)
- Veronica Egger
- Institute of Zoology, Regensburg University, Universitätsstr. 30, 93040, Regensburg, Germany.
| | - Thomas Kuner
- Department of Functional Neuroanatomy, Institute for Anatomy and Cell Biology, Heidelberg University, Im Neuenheimer Feld 307, 69120, Heidelberg, Germany
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24
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Lage-Rupprecht V, Zhou L, Bianchini G, Aghvami SS, Mueller M, Rózsa B, Sassoè-Pognetto M, Egger V. Presynaptic NMDARs cooperate with local spikes toward GABA release from the reciprocal olfactory bulb granule cell spine. eLife 2020; 9:e63737. [PMID: 33252329 PMCID: PMC7704106 DOI: 10.7554/elife.63737] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 11/10/2020] [Indexed: 12/16/2022] Open
Abstract
In the rodent olfactory bulb the smooth dendrites of the principal glutamatergic mitral cells (MCs) form reciprocal dendrodendritic synapses with large spines on GABAergic granule cells (GC), where unitary release of glutamate can trigger postsynaptic local activation of voltage-gated Na+-channels (Navs), that is a spine spike. Can such single MC input evoke reciprocal release? We find that unitary-like activation via two-photon uncaging of glutamate causes GC spines to release GABA both synchronously and asynchronously onto MC dendrites. This release indeed requires activation of Navs and high-voltage-activated Ca2+-channels (HVACCs), but also of NMDA receptors (NMDAR). Simulations show temporally overlapping HVACC- and NMDAR-mediated Ca2+-currents during the spine spike, and ultrastructural data prove NMDAR presence within the GABAergic presynapse. This cooperative action of presynaptic NMDARs allows to implement synapse-specific, activity-dependent lateral inhibition, and thus could provide an efficient solution to combinatorial percept synthesis in a sensory system with many receptor channels.
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Affiliation(s)
- Vanessa Lage-Rupprecht
- Neurophysiology, Institute of Zoology, Universität RegensburgRegensburgGermany
- Department of Bioinformatics, Fraunhofer SCAISankt AugustinGermany
| | - Li Zhou
- Neurophysiology, Institute of Zoology, Universität RegensburgRegensburgGermany
| | - Gaia Bianchini
- Neurophysiology, Institute of Zoology, Universität RegensburgRegensburgGermany
| | - S Sara Aghvami
- Neurophysiology, Institute of Zoology, Universität RegensburgRegensburgGermany
- School of Electrical and Computer Engineering, University of TehranTehranIslamic Republic of Iran
- School of Cognitive Sciences, Institute for Research in Fundamental Sciences (IPM)TehranIslamic Republic of Iran
| | - Max Mueller
- Neurophysiology, Institute of Zoology, Universität RegensburgRegensburgGermany
| | - Balázs Rózsa
- Two-Photon Imaging Center, Institute of Experimental Medicine, Hungarian Academy of SciencesBudapestHungary
| | | | - Veronica Egger
- Neurophysiology, Institute of Zoology, Universität RegensburgRegensburgGermany
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25
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Sokolov AM, Holmberg JC, Feliciano DM. The amino acid transporter Slc7a5 regulates the mTOR pathway and is required for granule cell development. Hum Mol Genet 2020; 29:3003-3013. [PMID: 32821949 PMCID: PMC7645712 DOI: 10.1093/hmg/ddaa186] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 07/03/2020] [Accepted: 08/15/2020] [Indexed: 12/11/2022] Open
Abstract
Pathogenic mutations in the solute carrier family 7 member 5 (SLC7A5) gene, which encodes an amino acid transporter cause microcephaly and seizures, yet the mechanisms responsible for these phenotypes are unclear. Models have demonstrated that Slc7a5 deletion is embryonic lethal and that these embryos lack a fully formed telencephalon. This phenotype is similar to that of mammalian target of rapamycin (mTOR) protein kinase deletion or mTOR inhibition. Notably, in many cells, Slc7a5 import of amino acids is required to maintain mTOR activity. Slc7a5 is present within neurogenic regions during embryogenesis, is found in cultured neurons and can modulate neuronal electrophysiological properties. However, Slc7a5 is also highly expressed within endothelial cells of the blood-brain barrier where removal in conditional mice leads to severe behavioral defects and non-cell autonomous changes in neurons. Therefore, the extent that neural Slc7a5 is required for development is unclear. Here, subventricular zone neural stem cells that generate olfactory bulb granule cell neurons were electroporated with SLC7A5 or Slc7a5 short hairpin RNA encoding plasmids. Although early phases of neural development were unaltered, Slc7a5 knockdown effected late phases of GC dendrite maturation and survival. Slc7a5 knockdown also decreased mTOR pathway activity. Ras homolog enriched in brain, an mTOR activator, rescued the effect of Slc7a5 knockdown on mTOR pathway activity and dendrite arbors. The data presented here demonstrate that Slc7a5 is required for GC mTOR pathway activity, maturation and survival, which may help explain why Slc7a5 mutations prevent normal brain development and function.
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Affiliation(s)
- Aidan M Sokolov
- Department of Biological Sciences, Clemson University, Clemson, SC 29634-0314, USA
| | - Jennie C Holmberg
- Department of Biological Sciences, Clemson University, Clemson, SC 29634-0314, USA
| | - David M Feliciano
- Department of Biological Sciences, Clemson University, Clemson, SC 29634-0314, USA
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26
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Wu A, Yu B, Chen Q, Matthews GA, Lu C, Campbell E, Tye KM, Komiyama T. Context-dependent plasticity of adult-born neurons regulated by cortical feedback. SCIENCE ADVANCES 2020; 6:6/42/eabc8319. [PMID: 33067236 PMCID: PMC7567600 DOI: 10.1126/sciadv.abc8319] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Accepted: 09/02/2020] [Indexed: 05/26/2023]
Abstract
In a complex and dynamic environment, the brain flexibly adjusts its circuits to preferentially process behaviorally relevant information. Here, we investigated how the olfactory bulb copes with this demand by examining the plasticity of adult-born granule cells (abGCs). We found that learning of olfactory discrimination elevates odor responses of young abGCs and increases their apical dendritic spines. This plasticity did not occur in abGCs during passive odor experience nor in resident granule cells (rGCs) during learning. Furthermore, we found that feedback projections from the piriform cortex show elevated activity during learning, and activating piriform feedback elicited stronger excitatory postsynaptic currents in abGCs than rGCs. Inactivation of piriform feedback blocked abGC plasticity during learning, and activation of piriform feedback during passive experience induced learning-like plasticity of abGCs. Our work describes a neural circuit mechanism that uses adult neurogenesis to update a sensory circuit to flexibly adapt to new behavioral demands.
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Affiliation(s)
- An Wu
- Neurobiology Section, and Center for Neural Circuits and Behavior, University of California San Diego, La Jolla, CA 92093, USA.
- Department of Neurosciences, and Halıcıoğlu Data Science Institute, University of California San Diego, La Jolla, CA 92093, USA
| | - Bin Yu
- Neurobiology Section, and Center for Neural Circuits and Behavior, University of California San Diego, La Jolla, CA 92093, USA
- Department of Neurosciences, and Halıcıoğlu Data Science Institute, University of California San Diego, La Jolla, CA 92093, USA
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA 92093, USA
| | - Qiyu Chen
- Neurobiology Section, and Center for Neural Circuits and Behavior, University of California San Diego, La Jolla, CA 92093, USA
- Department of Neurosciences, and Halıcıoğlu Data Science Institute, University of California San Diego, La Jolla, CA 92093, USA
| | | | - Chen Lu
- Neurobiology Section, and Center for Neural Circuits and Behavior, University of California San Diego, La Jolla, CA 92093, USA
- Department of Neurosciences, and Halıcıoğlu Data Science Institute, University of California San Diego, La Jolla, CA 92093, USA
| | - Evan Campbell
- Neurobiology Section, and Center for Neural Circuits and Behavior, University of California San Diego, La Jolla, CA 92093, USA
| | - Kay M Tye
- Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Takaki Komiyama
- Neurobiology Section, and Center for Neural Circuits and Behavior, University of California San Diego, La Jolla, CA 92093, USA.
- Department of Neurosciences, and Halıcıoğlu Data Science Institute, University of California San Diego, La Jolla, CA 92093, USA
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27
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Shepherd GM, Hines ML, Migliore M, Chen WR, Greer CA. Predicting brain organization with a computational model: 50-year perspective on lateral inhibition and oscillatory gating by dendrodendritic synapses. J Neurophysiol 2020; 124:375-387. [PMID: 32639901 DOI: 10.1152/jn.00175.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The first compartmental computer models of brain neurons using the Rall method predicted novel and unexpected dendrodendritic interactions between mitral and granule cells in the olfactory bulb. We review the models from a 50-year perspective on the work that has challenged, supported, and extended the original proposal that these interactions mediate both lateral inhibition and oscillatory activity, essential steps in the neural basis of olfactory processing and perception. We highlight strategies behind the neurophysiological experiments and the Rall methods that enhance the ability of detailed compartmental modeling to give counterintuitive predictions that lead to deeper insights into neural organization at the synaptic and circuit level. The application of these methods to mechanisms of neurogenesis and plasticity are exciting challenges for the future.
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Affiliation(s)
- Gordon M Shepherd
- Department of Neuroscience, Yale University School of Medicine, New Haven, Connecticut
| | - Michael L Hines
- Department of Neuroscience, Yale University School of Medicine, New Haven, Connecticut
| | - Michele Migliore
- Institute of Biophysics, National Research Council, Palermo, Italy
| | | | - Charles A Greer
- Department of Neuroscience, Yale University School of Medicine, New Haven, Connecticut
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28
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Effect of Interglomerular Inhibitory Networks on Olfactory Bulb Odor Representations. J Neurosci 2020; 40:5954-5969. [PMID: 32561671 DOI: 10.1523/jneurosci.0233-20.2020] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 06/06/2020] [Accepted: 06/09/2020] [Indexed: 11/21/2022] Open
Abstract
Lateral inhibition is a fundamental feature of circuits that process sensory information. In the mammalian olfactory system, inhibitory interneurons called short axon cells (SACs) comprise the first network mediating lateral inhibition between glomeruli, the functional units of early olfactory coding and processing. The connectivity of this network and its impact on odor representations is not well understood. To explore this question, we constructed a computational model of the interglomerular inhibitory network using detailed characterizations of SAC morphologies taken from mouse olfactory bulb (OB). We then examined how this network transformed glomerular patterns of odorant-evoked sensory input (taken from previously-published datasets) as a function of the selectivity of interglomerular inhibition. We examined three connectivity schemes: selective (each glomerulus connects to few others with heterogeneous strength), nonselective (glomeruli connect to most others with heterogenous strength), or global (glomeruli connect to all others with equal strength). We found that both selective and nonselective interglomerular networks could mediate heterogeneous patterns of inhibition across glomeruli when driven by realistic sensory input patterns, but that global inhibitory networks were unable to produce input-output transformations that matched experimental data and were poor mediators of intensity-dependent gain control. We further found that networks whose interglomerular connectivities were tuned by sensory input profile decorrelated odor representations moreeffectively. These results suggest that, despite their multiglomerular innervation patterns, SACs are capable of mediating odorant-specific patterns of inhibition between glomeruli that could, theoretically, be tuned by experience or evolution to optimize discrimination of particular odorants.SIGNIFICANCE STATEMENT Lateral inhibition is a key feature of circuitry in many sensory systems including vision, audition, and olfaction. We investigate how lateral inhibitory networks mediated by short axon cells (SACs) in the mouse olfactory bulb (OB) might shape odor representations as a function of their interglomerular connectivity. Using a computational model of interglomerular connectivity derived from experimental data, we find that SAC networks, despite their broad innervation patterns, can mediate heterogeneous patterns of inhibition across glomeruli, and that the canonical model of global inhibition does not generate experimentally observed responses to stimuli. In addition, inhibitory connections tuned by input statistics yield enhanced decorrelation of similar input patterns. These results elucidate how the organization of inhibition between neural elements may affect computations.
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29
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Wallace J, Lord J, Dissing-Olesen L, Stevens B, Murthy VN. Microglial depletion disrupts normal functional development of adult-born neurons in the olfactory bulb. eLife 2020; 9:e50531. [PMID: 32150529 PMCID: PMC7062469 DOI: 10.7554/elife.50531] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 01/13/2020] [Indexed: 12/11/2022] Open
Abstract
Microglia play key roles in regulating synapse development and refinement in the developing brain, but it is unknown whether they are similarly involved during adult neurogenesis. By transiently depleting microglia from the healthy adult mouse brain, we show that microglia are necessary for the normal functional development of adult-born granule cells (abGCs) in the olfactory bulb. Microglial depletion reduces the odor responses of developing, but not preexisting GCs in vivo in both awake and anesthetized mice. Microglia preferentially target their motile processes to interact with mushroom spines on abGCs, and when microglia are absent, abGCs develop smaller spines and receive weaker excitatory synaptic inputs. These results suggest that microglia promote the development of excitatory synapses onto developing abGCs, which may impact the function of these cells in the olfactory circuit.
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Affiliation(s)
- Jenelle Wallace
- Molecules, Cells, and Organisms Training Program, Harvard UniversityCambridgeUnited States
- Center for Brain Science, Harvard UniversityCambridgeUnited States
- Department of Molecular and Cellular Biology, Harvard UniversityCambridgeUnited States
- FM Kirby Neurobiology Center, Boston Children’s HospitalBostonUnited States
| | - Julia Lord
- Department of Molecular and Cellular Biology, Harvard UniversityCambridgeUnited States
| | - Lasse Dissing-Olesen
- FM Kirby Neurobiology Center, Boston Children’s HospitalBostonUnited States
- Harvard Medical SchoolBostonUnited States
| | - Beth Stevens
- FM Kirby Neurobiology Center, Boston Children’s HospitalBostonUnited States
- Harvard Medical SchoolBostonUnited States
- Stanley Center for Psychiatric Research, Broad Institute of MIT and HarvardCambridgeUnited States
- Howard Hughes Medical Institute, Boston Children’s HospitalBostonUnited States
| | - Venkatesh N Murthy
- Molecules, Cells, and Organisms Training Program, Harvard UniversityCambridgeUnited States
- Center for Brain Science, Harvard UniversityCambridgeUnited States
- Department of Molecular and Cellular Biology, Harvard UniversityCambridgeUnited States
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30
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Wu A, Yu B, Komiyama T. Plasticity in olfactory bulb circuits. Curr Opin Neurobiol 2020; 64:17-23. [PMID: 32062045 DOI: 10.1016/j.conb.2020.01.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 11/27/2019] [Accepted: 01/15/2020] [Indexed: 12/24/2022]
Abstract
Olfaction is crucial for animal survival and human well-being. The olfactory bulb is the obligatory input station for olfactory information. In contrast to the traditional view as a static relay station, recent evidence indicates that the olfactory bulb dynamically processes olfactory information in an experience-dependent and context-dependent manner. Here, we review recent studies on experience-dependent plasticity of the main circuit components within the olfactory bulb of rodents. We argue that the olfactory bulb plasticity allows optimal representations of behaviorally-relevant odors in the continuously changing olfactory environment.
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Affiliation(s)
- An Wu
- Neurobiology Section, Center for Neural Circuits and Behavior, University of California San Diego, La Jolla, CA 92093, USA; Department of Neurosciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Bin Yu
- Neurobiology Section, Center for Neural Circuits and Behavior, University of California San Diego, La Jolla, CA 92093, USA; Department of Neurosciences, University of California San Diego, La Jolla, CA 92093, USA; Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA 92093, USA
| | - Takaki Komiyama
- Neurobiology Section, Center for Neural Circuits and Behavior, University of California San Diego, La Jolla, CA 92093, USA; Department of Neurosciences, University of California San Diego, La Jolla, CA 92093, USA.
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31
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Pekarek BT, Hunt PJ, Arenkiel BR. Oxytocin and Sensory Network Plasticity. Front Neurosci 2020; 14:30. [PMID: 32063835 PMCID: PMC7000660 DOI: 10.3389/fnins.2020.00030] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 01/10/2020] [Indexed: 12/22/2022] Open
Abstract
An essential characteristic of nervous systems is their capacity to reshape functional connectivity in response to physiological and environmental cues. Endogenous signals, including neuropeptides, governs nervous system plasticity. Particularly, oxytocin has been recognized for its role in mediating activity-dependent circuit changes. These oxytocin-dependent changes occur at the synaptic level and consequently shape the cellular composition of circuits. Here we discuss recent advances that illustrate how oxytocin functions to reshape neural circuitry in response to environmental changes. Excitingly, recent findings pave the way for promising therapeutic applications of oxytocin to treat neurodevelopmental and neuropsychiatric diseases.
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Affiliation(s)
- Brandon T. Pekarek
- Genetics and Genomics Program, Baylor College of Medicine, Houston, TX, United States
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States
| | - Patrick J. Hunt
- Genetics and Genomics Program, Baylor College of Medicine, Houston, TX, United States
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States
- Medical Scientist Training Program, Baylor College of Medicine, Houston, TX, United States
| | - Benjamin R. Arenkiel
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, United States
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Houston, TX, United States
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32
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The use of bioactive matrices in regenerative therapies for traumatic brain injury. Acta Biomater 2020; 102:1-12. [PMID: 31751809 DOI: 10.1016/j.actbio.2019.11.032] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 10/22/2019] [Accepted: 11/13/2019] [Indexed: 01/01/2023]
Abstract
Functional deficits due to neuronal loss are a common theme across multiple neuropathologies, including traumatic brain injury (TBI). Apart from mitigating cell death, another approach to treating brain injuries involves re-establishing the neural circuitry at the lesion site by utilizing exogeneous and/or endogenous stem cells to achieve functional recovery. While there has been limited success, the emergence of new bioactive matrices that promote neural repair introduces new perspectives on the development of regenerative therapies for TBI. This review briefly discusses current development on cell-based therapies and the use of bioactive matrices, hydrogels in particular, when incorporated in regenerative therapies. Desirable characteristics of bioactive matrices that have been shown to augment neural repair in TBI models were identified and further discussed. Understanding the relative outcomes of newly developed biomaterials implanted in vivo can better guide the development of biomaterials as a therapeutic strategy, for biomaterial-based cellular therapies are still in their nascent stages. Nonetheless, the value of bioactive matrices as a treatment for acute brain injuries should be appreciated and further developed. STATEMENT OF SIGNIFICANCE: Cell-based therapies have received attention as an alternative therapeutic strategy to improve clinical outcome post-traumatic brain injury but have achieved limited success. Whilst the incorporation of newly developed biomaterials in regenerative therapies has shown promise in augmenting neural repair, studies have revealed new hurdles which must be overcome to improve their therapeutic efficacy. This review discusses the recent development of cell-based therapies with a specific focus on the use of bioactive matrices in the form of hydrogels, to complement cell transplantation within the injured brain. Moreover, this review consolidates in vivo animal studies that demonstrate relative functional outcome upon the implantation of different biomaterials to highlight their desirable traits to guide their development for regenerative therapies in traumatic brain injury.
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33
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Xu X, Cang J, Riecke H. Development and binocular matching of orientation selectivity in visual cortex: a computational model. J Neurophysiol 2020; 123:1305-1319. [PMID: 31913758 DOI: 10.1152/jn.00386.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In mouse visual cortex, right after eye opening binocular cells have different preferred orientations for input from the two eyes. With normal visual experience during a critical period, these preferred orientations evolve and eventually become well matched. To gain insight into the matching process, we developed a computational model of a cortical cell receiving orientation selective inputs via plastic synapses. The model captures the experimentally observed matching of the preferred orientations, the dependence of matching on ocular dominance of the cell, and the relationship between the degree of matching and the resulting monocular orientation selectivity. Moreover, our model puts forward testable predictions: 1) The matching speed increases with initial ocular dominance. 2) While the matching improves more slowly for cells that are more orientation selective, the selectivity increases faster for better matched cells during the matching process. This suggests that matching drives orientation selectivity but not vice versa. 3) There are two main routes to matching: the preferred orientations either drift toward each other or one of the orientations switches suddenly. The latter occurs for cells with large initial mismatch and can render the cells monocular. We expect that these results provide insight more generally into the development of neuronal systems that integrate inputs from multiple sources, including different sensory modalities.NEW & NOTEWORTHY Animals gather information through multiple modalities (vision, audition, touch, etc.). These information streams have to be merged coherently to provide a meaningful representation of the world. Thus, for neurons in visual cortex V1, the orientation selectivities for inputs from the two eyes have to match to enable binocular vision. We analyze the postnatal process underlying this matching using computational modeling. It captures recent experimental results and reveals interdependence between matching, ocular dominance, and orientation selectivity.
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Affiliation(s)
- Xize Xu
- Department of Engineering Science and Applied Mathematics, Northwestern University, Evanston, Illinois
| | - Jianhua Cang
- Department of Biology and Department of Psychology, University of Virginia, Charlottesville, Virginia
| | - Hermann Riecke
- Department of Engineering Science and Applied Mathematics, Northwestern University, Evanston, Illinois
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34
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Platel JC, Angelova A, Bugeon S, Wallace J, Ganay T, Chudotvorova I, Deloulme JC, Béclin C, Tiveron MC, Coré N, Murthy VN, Cremer H. Neuronal integration in the adult mouse olfactory bulb is a non-selective addition process. eLife 2019; 8:44830. [PMID: 31294694 PMCID: PMC6634973 DOI: 10.7554/elife.44830] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 07/07/2019] [Indexed: 12/25/2022] Open
Abstract
Adult neurogenesis in the olfactory bulb (OB) is considered as a competition in which neurons scramble during a critical selection period for integration and survival. Moreover, newborn neurons are thought to replace pre-existing ones that die. Despite indirect evidence supporting this model, systematic in vivo observations are still scarce. We used two-photon in vivo imaging to study neuronal integration and survival. We show that loss of new neurons in the OB after arrival at terminal positions occurs only at low levels. Moreover, long-term observations showed that no substantial cell death occurred at later stages. Neuronal death was induced by standard doses of thymidine analogs, but disappeared when low doses were used. Finally, we demonstrate that the OB grows throughout life. This shows that neuronal selection during OB-neurogenesis does not occur after neurons reached stable positions. Moreover, this suggests that OB neurogenesis does not represent neuronal turnover but lifelong neuronal addition.
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Affiliation(s)
| | | | - Stephane Bugeon
- Aix-Marseille University, CNRS, IBDM, UMR 7288, Marseille, France
| | - Jenelle Wallace
- Department of Molecular & Cellular Biology, Harvard University, Cambridge, United States
| | - Thibault Ganay
- Aix-Marseille University, CNRS, IBDM, UMR 7288, Marseille, France
| | | | | | | | | | - Nathalie Coré
- Aix-Marseille University, CNRS, IBDM, UMR 7288, Marseille, France
| | - Venkatesh N Murthy
- Department of Molecular & Cellular Biology, Harvard University, Cambridge, United States
| | - Harold Cremer
- Aix-Marseille University, CNRS, IBDM, UMR 7288, Marseille, France
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35
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Farhoodi R, Lansdell BJ, Kording KP. Quantifying How Staining Methods Bias Measurements of Neuron Morphologies. Front Neuroinform 2019; 13:36. [PMID: 31191283 PMCID: PMC6541099 DOI: 10.3389/fninf.2019.00036] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Accepted: 04/25/2019] [Indexed: 12/20/2022] Open
Abstract
The process through which neurons are labeled is a key methodological choice in measuring neuron morphology. However, little is known about how this choice may bias measurements. To quantify this bias we compare the extracted morphology of neurons collected from the same rodent species, experimental condition, gender distribution, age distribution, brain region and putative cell type, but obtained with 19 distinct staining methods. We found strong biases on measured features of morphology. These were largest in features related to the coverage of the dendritic tree (e.g., the total dendritic tree length). Understanding measurement biases is crucial for interpreting morphological data.
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Affiliation(s)
- Roozbeh Farhoodi
- Department of Mathematics, Sharif University of Technology, Tehran, Iran
| | | | - Konrad Paul Kording
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, United States.,Department of Neuroscience, University of Pennsylvania, Philadelphia, PA, United States
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36
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Li S, Li W, Wu X, Li J, Yang J, Tu C, Ye X, Ling S. Olfactory deficit is associated with mitral cell dysfunction in the olfactory bulb of P301S tau transgenic mice. Brain Res Bull 2019; 148:34-45. [PMID: 30902575 DOI: 10.1016/j.brainresbull.2019.03.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Revised: 03/09/2019] [Accepted: 03/14/2019] [Indexed: 01/24/2023]
Abstract
Neurofibrillary tangles consisting of hyperphosphorylated tau (P-tau) are the neuropathological hallmark of Alzheimer's disease (AD), and olfaction disorder is an early symptom of AD. However, the link between P-tau aggregation and olfaction disorder remains unclear. In this study, the expression of P-tau in the olfactory bulb (OB), particularly in the mitral cell layer (MCL), external plexiform layer (EPL), and granule cell layer (GCL), of AD patients was found to be significantly higher than that in the OB of normal aging subjects, which suggested that these layers in the OB were susceptible to P-tau. The P301S tau transgenic mice (P301S mice) exhibit AD-like features, which can be characterized by olfactory dysfunction that precedes cognitive disorder. Importantly, the excessive P-tau expression in the OB of P301S mice, particularly in MCs, was associated with MC loss at 9 months of age, and decreased MC firing activities started to be observed at 2 months of age. Our results revealed that MCs might contribute to olfactory dysfunction in P301S mice. Furthermore, we described an aberrant dendro-dendritic synaptic structure between granule cells (GCs) and MCs and abnormal gamma oscillations in the EPL of the OB, and these findings indicated that P-tau might disrupt the regulation of MCs by GCs in P301S mice starting at 5 months of age. These data showed that the reduction in the MC firing frequency at 2 months of age might not be caused by GC suppression. Based on these findings, we speculated that MCs are a putative target for the treatment of P-tau-induced early olfactory dysfunction, and thus, an exploration of the specific causes and mechanisms of MC functional changes in P301S mice is crucial.
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Affiliation(s)
- Shanshan Li
- Institute of Neuroscience and Anatomy, School of Medicine, Zhejiang University, Hangzhou, China
| | - Weiyun Li
- Institute of Neuroscience and Anatomy, School of Medicine, Zhejiang University, Hangzhou, China; Department of Clinical Medicine, Zhejiang University City College, Hangzhou, China
| | - Xuewei Wu
- Institute of Neuroscience and Anatomy, School of Medicine, Zhejiang University, Hangzhou, China
| | - Jing Li
- Institute of Neuroscience and Anatomy, School of Medicine, Zhejiang University, Hangzhou, China
| | - Jing Yang
- Institute of Neuroscience and Anatomy, School of Medicine, Zhejiang University, Hangzhou, China
| | - Chunlong Tu
- Biosensor National Special Laboratory, Key Laboratory of BME of the Ministry of Education, Zhejiang University, Hangzhou, China
| | - Xuesong Ye
- Biosensor National Special Laboratory, Key Laboratory of BME of the Ministry of Education, Zhejiang University, Hangzhou, China.
| | - Shucai Ling
- Institute of Neuroscience and Anatomy, School of Medicine, Zhejiang University, Hangzhou, China.
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37
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Adams W, Graham JN, Han X, Riecke H. Top-down inputs drive neuronal network rewiring and context-enhanced sensory processing in olfaction. PLoS Comput Biol 2019; 15:e1006611. [PMID: 30668563 PMCID: PMC6358160 DOI: 10.1371/journal.pcbi.1006611] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2018] [Revised: 02/01/2019] [Accepted: 10/29/2018] [Indexed: 11/18/2022] Open
Abstract
Much of the computational power of the mammalian brain arises from its extensive top-down projections. To enable neuron-specific information processing these projections have to be precisely targeted. How such a specific connectivity emerges and what functions it supports is still poorly understood. We addressed these questions in silico in the context of the profound structural plasticity of the olfactory system. At the core of this plasticity are the granule cells of the olfactory bulb, which integrate bottom-up sensory inputs and top-down inputs delivered by vast top-down projections from cortical and other brain areas. We developed a biophysically supported computational model for the rewiring of the top-down projections and the intra-bulbar network via adult neurogenesis. The model captures various previous physiological and behavioral observations and makes specific predictions for the cortico-bulbar network connectivity that is learned by odor exposure and environmental contexts. Specifically, it predicts that-after learning-the granule-cell receptive fields with respect to sensory and with respect to cortical inputs are highly correlated. This enables cortical cells that respond to a learned odor to enact disynaptic inhibitory control specifically of bulbar principal cells that respond to that odor. For this the reciprocal nature of the granule cell synapses with the principal cells is essential. Functionally, the model predicts context-enhanced stimulus discrimination in cluttered environments ('olfactory cocktail parties') and the ability of the system to adapt to its tasks by rapidly switching between different odor-processing modes. These predictions are experimentally testable. At the same time they provide guidance for future experiments aimed at unraveling the cortico-bulbar connectivity.
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Affiliation(s)
- Wayne Adams
- Engineering Sciences and Applied Mathematics, Northwestern University, Evanston, IL, USA
| | - James N. Graham
- Engineering Sciences and Applied Mathematics, Northwestern University, Evanston, IL, USA
| | - Xuchen Han
- Mathematics, Northwestern University, Evanston, IL, USA
| | - Hermann Riecke
- Engineering Sciences and Applied Mathematics, Northwestern University, Evanston, IL, USA
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38
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Vinograd A, Fuchs-Shlomai Y, Stern M, Mukherjee D, Gao Y, Citri A, Davison I, Mizrahi A. Functional Plasticity of Odor Representations during Motherhood. Cell Rep 2018; 21:351-365. [PMID: 29020623 PMCID: PMC5643523 DOI: 10.1016/j.celrep.2017.09.038] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 06/21/2017] [Accepted: 09/11/2017] [Indexed: 01/24/2023] Open
Abstract
Motherhood is accompanied by new behaviors aimed at ensuring the wellbeing of the offspring. Olfaction plays a key role in guiding maternal behaviors during this transition. We studied functional changes in the main olfactory bulb (OB) of mothers in mice. Using in vivo two-photon calcium imaging, we studied the sensory representation of odors by mitral cells (MCs). We show that MC responses to monomolecular odors become sparser and weaker in mothers. In contrast, responses to biologically relevant odors are spared from sparsening or strengthen. MC responses to mixtures and to a range of concentrations suggest that these differences between odor responses cannot be accounted for by mixture suppressive effects or gain control mechanisms. In vitro whole-cell recordings show an increase in inhibitory synaptic drive onto MCs. The increase of inhibitory tone may contribute to the general decrease in responsiveness and concomitant enhanced representation of specific odors. MCs of mothers show sparser responses for pure odors MCs of mothers have stronger inhibitory drive onto MCs MCs of mothers show stronger responses to natural odors MC ensemble coding is improved for natural but not pure odors
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Affiliation(s)
- Amit Vinograd
- Department of Neurobiology, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 91904, Israel; The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 91904, Israel
| | - Yael Fuchs-Shlomai
- Department of Neurobiology, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 91904, Israel; The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 91904, Israel
| | - Merav Stern
- Department of Applied Mathematics, University of Washington, Seattle, WA, USA
| | - Diptendu Mukherjee
- Department of Chemical Biology, Institute of Life Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 91904, Israel; The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 91904, Israel
| | - Yuan Gao
- Department of Biology, Boston University, Boston, MA, USA
| | - Ami Citri
- Department of Chemical Biology, Institute of Life Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 91904, Israel; The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 91904, Israel
| | - Ian Davison
- Department of Biology, Boston University, Boston, MA, USA
| | - Adi Mizrahi
- Department of Neurobiology, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 91904, Israel; The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 91904, Israel.
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39
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Synchronization by uncorrelated noise: interacting rhythms in interconnected oscillator networks. Sci Rep 2018; 8:6949. [PMID: 29725054 PMCID: PMC5934367 DOI: 10.1038/s41598-018-24670-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 04/06/2018] [Indexed: 12/28/2022] Open
Abstract
Oscillators coupled in a network can synchronize with each other to yield a coherent population rhythm. How do multiple such rhythms interact with each other? Do these collective oscillations synchronize like individual oscillators? We show that this is not the case: for strong, inhibitory coupling rhythms can become synchronized by noise. In contrast to stochastic synchronization, this new mechanism synchronizes the rhythms even if the noisy inputs to different oscillators are completely uncorrelated. Key for the synchrony across networks is the reduced synchrony within the networks: it substantially increases the frequency range across which the networks can be entrained by other networks or by periodic pacemaker-like inputs. We demonstrate this type of robust synchronization for different classes of oscillators and network connectivities. The synchronization of different population rhythms is expected to be relevant for brain rhythms.
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40
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Galliano E, Franzoni E, Breton M, Chand AN, Byrne DJ, Murthy VN, Grubb MS. Embryonic and postnatal neurogenesis produce functionally distinct subclasses of dopaminergic neuron. eLife 2018; 7:e32373. [PMID: 29676260 PMCID: PMC5935487 DOI: 10.7554/elife.32373] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 04/04/2018] [Indexed: 11/13/2022] Open
Abstract
Most neurogenesis in the mammalian brain is completed embryonically, but in certain areas the production of neurons continues throughout postnatal life. The functional properties of mature postnatally generated neurons often match those of their embryonically produced counterparts. However, we show here that in the olfactory bulb (OB), embryonic and postnatal neurogenesis produce functionally distinct subpopulations of dopaminergic (DA) neurons. We define two subclasses of OB DA neuron by the presence or absence of a key subcellular specialisation: the axon initial segment (AIS). Large AIS-positive axon-bearing DA neurons are exclusively produced during early embryonic stages, leaving small anaxonic AIS-negative cells as the only DA subtype generated via adult neurogenesis. These populations are functionally distinct: large DA cells are more excitable, yet display weaker and - for certain long-latency or inhibitory events - more broadly tuned responses to odorant stimuli. Embryonic and postnatal neurogenesis can therefore generate distinct neuronal subclasses, placing important constraints on the functional roles of adult-born neurons in sensory processing.
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Affiliation(s)
- Elisa Galliano
- Centre for Developmental NeurobiologyInstitute of Psychiatry, Psychology and Neuroscience, King’s College LondonLondonUnited Kingdom
- Department of Molecular and Cellular BiologyHarvard UniversityCambridgeUnited States
- Centre for Brain ScienceHarvard UniversityCambridgeUnited States
| | - Eleonora Franzoni
- Centre for Developmental NeurobiologyInstitute of Psychiatry, Psychology and Neuroscience, King’s College LondonLondonUnited Kingdom
| | - Marine Breton
- Centre for Developmental NeurobiologyInstitute of Psychiatry, Psychology and Neuroscience, King’s College LondonLondonUnited Kingdom
| | - Annisa N Chand
- Centre for Developmental NeurobiologyInstitute of Psychiatry, Psychology and Neuroscience, King’s College LondonLondonUnited Kingdom
| | - Darren J Byrne
- Centre for Developmental NeurobiologyInstitute of Psychiatry, Psychology and Neuroscience, King’s College LondonLondonUnited Kingdom
| | - Venkatesh N Murthy
- Department of Molecular and Cellular BiologyHarvard UniversityCambridgeUnited States
- Centre for Brain ScienceHarvard UniversityCambridgeUnited States
| | - Matthew S Grubb
- Centre for Developmental NeurobiologyInstitute of Psychiatry, Psychology and Neuroscience, King’s College LondonLondonUnited Kingdom
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41
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Ackels T, Schaefer AT. The maps they are a-changin': plasticity in odor representation in interneurons. Nat Neurosci 2018; 20:128-129. [PMID: 28127039 DOI: 10.1038/nn.4484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Tobias Ackels
- Neurophysiology of Behaviour Lab, The Francis Crick Institute, London, UK
| | - Andreas T Schaefer
- Neurophysiology of Behaviour Lab, The Francis Crick Institute, London, UK.,Department of Neuroscience, Physiology &Pharmacology, University College London, London, UK
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42
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Li WL, Chu MW, Wu A, Suzuki Y, Imayoshi I, Komiyama T. Adult-born neurons facilitate olfactory bulb pattern separation during task engagement. eLife 2018; 7:e33006. [PMID: 29533179 PMCID: PMC5912906 DOI: 10.7554/elife.33006] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2017] [Accepted: 03/12/2018] [Indexed: 11/18/2022] Open
Abstract
The rodent olfactory bulb incorporates thousands of newly generated inhibitory neurons daily throughout adulthood, but the role of adult neurogenesis in olfactory processing is not fully understood. Here we adopted a genetic method to inducibly suppress adult neurogenesis and investigated its effect on behavior and bulbar activity. Mice without young adult-born neurons (ABNs) showed normal ability in discriminating very different odorants but were impaired in fine discrimination. Furthermore, two-photon calcium imaging of mitral cells (MCs) revealed that the ensemble odor representations of similar odorants were more ambiguous in the ablation animals. This increased ambiguity was primarily due to a decrease in MC suppressive responses. Intriguingly, these deficits in MC encoding were only observed during task engagement but not passive exposure. Our results indicate that young olfactory ABNs are essential for the enhancement of MC pattern separation in a task engagement-dependent manner, potentially functioning as a gateway for top-down modulation.
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Affiliation(s)
- Wankun L Li
- Neurobiology Section, Center for Neural Circuits and BehaviorUniversity of California, San DiegoSan DiegoUnited States
- Department of NeurosciencesUniversity of California, San DiegoSan DiegoUnited States
| | - Monica W Chu
- Neurobiology Section, Center for Neural Circuits and BehaviorUniversity of California, San DiegoSan DiegoUnited States
- Department of NeurosciencesUniversity of California, San DiegoSan DiegoUnited States
| | - An Wu
- Neurobiology Section, Center for Neural Circuits and BehaviorUniversity of California, San DiegoSan DiegoUnited States
- Department of NeurosciencesUniversity of California, San DiegoSan DiegoUnited States
| | - Yusuke Suzuki
- Medical Innovation Center/SK Project, Graduate School of MedicineKyoto UniversityKyotoJapan
| | | | - Takaki Komiyama
- Neurobiology Section, Center for Neural Circuits and BehaviorUniversity of California, San DiegoSan DiegoUnited States
- Department of NeurosciencesUniversity of California, San DiegoSan DiegoUnited States
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43
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Abstract
Odor–reward association during appetitive learning is a fundamental process that requires multiple forms of plasticity. In the adult olfactory bulb, the continual production of newborn interneurons contributes to the functional plasticity of the system, placing the newcomers in a key position to participate in olfactory associative learning. Here, we demonstrate that adult-born neurons, but not preexisting ones, contain information about learned positive value. Moreover, specific heightening of this signal improves associative learning and odor value update and is enough in some cases to trigger behavior even without odor stimulus. Collectively, our findings show an important role of this adult-born interneuron population in odor–reward association and unveil the relevance of odor value encoding at early stages of sensory processing. Olfaction is an important sensory modality driving fundamental behaviors. During odor-dependent learning, a positive value is commonly assigned to an odorant, and multiple forms of plasticity are involved when such odor–reward associations are formed. In rodents, one of the mechanisms underlying plasticity in the olfactory bulb consists in recruiting new neurons daily throughout life. However, it is still unknown whether adult-born neurons might participate in encoding odor value. Here, we demonstrate that exposure to reward-associated odors specifically increases activity of adult-born neurons but not preexisting neurons. Remarkably, adult-born neuron activation during rewarded odor presentation heightens discrimination learning and enhances the ability to update the odor value during reversal association. Moreover, in some cases, activation of this interneuron population can trigger olfactory learning without sensory stimulation. Taken together, our results show a specific involvement of adult-born neurons in facilitating odor–reward association during adaptive learning.
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44
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Wallace JL, Wienisch M, Murthy VN. Development and Refinement of Functional Properties of Adult-Born Neurons. Neuron 2017; 96:883-896.e7. [PMID: 29056299 PMCID: PMC5789450 DOI: 10.1016/j.neuron.2017.09.039] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 07/26/2017] [Accepted: 09/22/2017] [Indexed: 01/21/2023]
Abstract
New neurons appear only in a few regions of the adult mammalian brain and become integrated into existing circuits. Little is known about the functional development of individual neurons in vivo. We examined the functional life history of adult-born granule cells (abGCs) in the olfactory bulb using multiphoton imaging in awake and anesthetized mice. We found that abGCs can become responsive to odorants soon after they arrive in the olfactory bulb. Tracking identified abGCs over weeks revealed that the robust and broadly tuned responses of most newly arrived abGCs gradually become more selective over a period of ∼3 weeks, but a small fraction achieves broader tuning with maturation. Enriching the olfactory environment of mice prolonged the period over which abGCs were strongly and broadly responsive to odorants. Our data offer direct support for rapid integration of adult-born neurons into existing circuits, followed by experience-dependent refinement of their functional connectivity.
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Affiliation(s)
- Jenelle L Wallace
- Molecules, Cells, and Organisms training program, Harvard University, Cambridge, MA 02138, USA; Center for Brain Science, Harvard University, Cambridge, MA 02138, USA; Department of Molecular & Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Martin Wienisch
- Center for Brain Science, Harvard University, Cambridge, MA 02138, USA; Department of Molecular & Cellular Biology, Harvard University, Cambridge, MA 02138, USA.
| | - Venkatesh N Murthy
- Center for Brain Science, Harvard University, Cambridge, MA 02138, USA; Department of Molecular & Cellular Biology, Harvard University, Cambridge, MA 02138, USA.
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45
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Xu M, Huang Y, Li K, Cheng X, Li G, Liu M, Nie Y, Geng S, Zhao S. Developmental exposure of decabromodiphenyl ether impairs subventricular zone neurogenesis and morphology of granule cells in mouse olfactory bulb. Arch Toxicol 2017; 92:529-539. [DOI: 10.1007/s00204-017-2059-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 08/31/2017] [Indexed: 11/29/2022]
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46
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Hardy D, Saghatelyan A. Different forms of structural plasticity in the adult olfactory bulb. NEUROGENESIS 2017; 4:e1301850. [PMID: 28596977 DOI: 10.1080/23262133.2017.1301850] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Revised: 02/24/2017] [Accepted: 02/27/2017] [Indexed: 12/26/2022]
Abstract
The adult olfactory bulb (OB) continuously receives new interneurons that integrate into the functional neuronal network and that play an important role in odor information processing and olfactory behavior. Adult neuronal progenitors are derived from neural stem cells in the subventricular zone (SVZ) bordering the lateral ventricle. They migrate long distances along the rostral migratory stream (RMS) toward the OB where they differentiate into interneurons, mature, and establish synapses with tufted or mitral cells (MC), the principal neurons in the OB. The plasticity provided by both adult-born and pre-existing early-born neurons depends on the formation and pruning of new synaptic contacts that adapt the functioning of the bulbar network to changing environmental conditions. However, the formation of new synapses occurs over a long time scale (hours-days), whereas some changes in environmental conditions can occur more rapidly, requiring a much faster adjustment of neuronal networks. A new form of structural remodeling of adult-born, but not early-born, neurons was recently brought to light. This plasticity, which is based on the activity-dependent relocation of mature spines of GCs toward the dendrites of active principal cells, may allow a more rapid adjustment of the neuronal network in response to quick and persistent changes in sensory inputs. In this mini-review we discuss the different forms of structural plasticity displayed by adult-born and early-born neurons and the possibility that these different forms of structural remodeling may fulfill distinct roles in odor information processing.
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Affiliation(s)
- Delphine Hardy
- Cellular Neurobiology Unit, Centre de Recherche de l'Institut Universitaire en Santé Mentale de Québec, Quebec City, QC, Canada
| | - Armen Saghatelyan
- Cellular Neurobiology Unit, Centre de Recherche de l'Institut Universitaire en Santé Mentale de Québec, Quebec City, QC, Canada.,Department of Psychiatry and Neuroscience, Université Laval, Quebec City, QC, Canada
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47
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Sailor KA, Schinder AF, Lledo PM. Adult neurogenesis beyond the niche: its potential for driving brain plasticity. Curr Opin Neurobiol 2016; 42:111-117. [PMID: 28040643 DOI: 10.1016/j.conb.2016.12.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 11/30/2016] [Accepted: 12/05/2016] [Indexed: 12/14/2022]
Abstract
Adult neurogenesis emerges as a tremendous form of plasticity with the continuous addition and loss of neurons in the adult brain. It is unclear how preexisting adult circuits generated during development are capable of modifying existing connections to accommodate the thousands of new synapses formed and exchanged each day. Here we first make parallels with sensory deprivation studies and its ability to induce preexisting non-neurogenic adult circuits to undergo massive reorganization. We then review recent studies that show high structural and synaptic plasticity in circuits directly connected to adult-born neurons. Finally, we propose future directions in the field to decipher how host circuits can accommodate new neuron integration and to determine the impact of adult neurogenesis on global brain plasticity.
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Affiliation(s)
- Kurt A Sailor
- Laboratory for Perception and Memory, Pasteur Institute, F-75015 Paris, France; Centre National de la Recherche Scientifique (CNRS), Unité de Recherche Associée (UMR3571), F-75015 Paris, France
| | - Alejandro F Schinder
- Laboratory of Neuronal Plasticity, Leloir Institute (IIBBA - CONICET), Av. Patricias Argentinas 435, Buenos Aires C1405BWE, Argentina
| | - Pierre-Marie Lledo
- Laboratory for Perception and Memory, Pasteur Institute, F-75015 Paris, France; Centre National de la Recherche Scientifique (CNRS), Unité de Recherche Associée (UMR3571), F-75015 Paris, France.
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