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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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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3
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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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4
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Characterization by Gene Expression Analysis of Two Groups of Dopaminergic Cells Isolated from the Mouse Olfactory Bulb. BIOLOGY 2023; 12:biology12030367. [PMID: 36979058 PMCID: PMC10045757 DOI: 10.3390/biology12030367] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 02/02/2023] [Accepted: 02/23/2023] [Indexed: 03/02/2023]
Abstract
The olfactory bulb (OB) is one of two regions of the mammalian brain which undergo continuous neuronal replacement during adulthood. A significant fraction of the cells added in adulthood to the bulbar circuitry is constituted by dopaminergic (DA) neurons. We took advantage of a peculiar property of dopaminergic neurons in transgenic mice expressing eGFP under the tyrosine hydroxylase (TH) promoter: while DA neurons located in the glomerular layer (GL) display full electrophysiological maturation, eGFP+ cells in the mitral layer (ML) show characteristics of immature cells. In addition, they also display a lower fluorescence intensity, possibly reflecting different degrees of maturation. To investigate whether this difference in maturation might be confirmed at the gene expression level, we used a fluorescence-activated cell sorting technique on enzymatically dissociated cells of the OB. The cells were divided into two groups based on their level of fluorescence, possibly corresponding to immature ML cells and fully mature DA neurons from the GL. Semiquantitative real-time PCR was performed to detect the level of expression of genes linked to the degree of maturation of DA neurons. We showed that indeed the cells expressing low eGFP fluorescence are immature neurons. Our method can be further used to explore the differences between these two groups of DA neurons.
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5
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Seng C, Luo W, Földy C. Circuit formation in the adult brain. Eur J Neurosci 2022; 56:4187-4213. [PMID: 35724981 PMCID: PMC9546018 DOI: 10.1111/ejn.15742] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 06/08/2022] [Accepted: 06/09/2022] [Indexed: 11/30/2022]
Abstract
Neurons in the mammalian central nervous system display an enormous capacity for circuit formation during development but not later in life. In principle, new circuits could be also formed in adult brain, but the absence of the developmental milieu and the presence of growth inhibition and hundreds of working circuits are generally viewed as unsupportive for such a process. Here, we bring together evidence from different areas of neuroscience—such as neurological disorders, adult‐brain neurogenesis, innate behaviours, cell grafting, and in vivo cell reprogramming—which demonstrates robust circuit formation in adult brain. In some cases, adult‐brain rewiring is ongoing and required for certain types of behaviour and memory, while other cases show significant promise for brain repair in disease models. Together, these examples highlight that the adult brain has higher capacity for structural plasticity than previously recognized. Understanding the underlying mechanisms behind this retained plasticity has the potential to advance basic knowledge regarding the molecular organization of synaptic circuits and could herald a new era of neural circuit engineering for therapeutic repair.
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Affiliation(s)
- Charlotte Seng
- Laboratory of Neural Connectivity, Brain Research Institute, Faculties of Medicine and Science, University of Zurich, Zürich, Switzerland
| | - Wenshu Luo
- Laboratory of Neural Connectivity, Brain Research Institute, Faculties of Medicine and Science, University of Zurich, Zürich, Switzerland
| | - Csaba Földy
- Laboratory of Neural Connectivity, Brain Research Institute, Faculties of Medicine and Science, University of Zurich, Zürich, Switzerland
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6
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Deciphering heterogeneous populations of migrating cells based on the computational assessment of their dynamic properties. Stem Cell Reports 2022; 17:911-923. [PMID: 35303437 PMCID: PMC9023771 DOI: 10.1016/j.stemcr.2022.02.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 02/17/2022] [Accepted: 02/18/2022] [Indexed: 11/23/2022] Open
Abstract
Neuronal migration is a highly dynamic process, and multiple cell movement metrics can be extracted from time-lapse imaging datasets. However, these parameters alone are often insufficient to evaluate the heterogeneity of neuroblast populations. We developed an analytical pipeline based on reducing the dimensions of the dataset by principal component analysis (PCA) and determining sub-populations using k-means, supported by the elbow criterion method and validated by a decision tree algorithm. We showed that neuroblasts derived from the same adult neural stem cell (NSC) lineage as well as across different lineages are heterogeneous and can be sub-divided into different clusters based on their dynamic properties. Interestingly, we also observed overlapping clusters for neuroblasts derived from different NSC lineages. We further showed that genetic perturbations or environmental stimuli affect the migratory properties of neuroblasts in a sub-cluster-specific manner. Our data thus provide a framework for assessing the heterogeneity of migrating neuroblasts. Pipeline to study the heterogeneity of migrating cells based on their dynamic properties Neuroblasts derived from the same neural stem cell (NSC) lineage are heterogeneous Neuroblasts derived from different NSC lineages have overlapping and distinct clusters These clusters are differently affected by genetic factors or environmental stimuli
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7
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Exercise mimetics: harnessing the therapeutic effects of physical activity. Nat Rev Drug Discov 2021; 20:862-879. [PMID: 34103713 DOI: 10.1038/s41573-021-00217-1] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/22/2021] [Indexed: 02/05/2023]
Abstract
Exercise mimetics are a proposed class of therapeutics that specifically mimic or enhance the therapeutic effects of exercise. Increased physical activity has demonstrated positive effects in preventing and ameliorating a wide range of diseases, including brain disorders such as Alzheimer disease and dementia, cancer, diabetes and cardiovascular disease. This article discusses the molecular mechanisms and signalling pathways associated with the beneficial effects of physical activity, focusing on effects on brain function and cognitive enhancement. Emerging therapeutic targets and strategies for the development of exercise mimetics, particularly in the field of central nervous system disorders, as well as the associated opportunities and challenges, are discussed.
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8
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Capsoni S, Fogli Iseppe A, Casciano F, Pignatelli A. Unraveling the Role of Dopaminergic and Calretinin Interneurons in the Olfactory Bulb. Front Neural Circuits 2021; 15:718221. [PMID: 34690707 PMCID: PMC8531203 DOI: 10.3389/fncir.2021.718221] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 08/31/2021] [Indexed: 11/27/2022] Open
Abstract
The perception and discriminating of odors are sensory activities that are an integral part of our daily life. The first brain region where odors are processed is the olfactory bulb (OB). Among the different cell populations that make up this brain area, interneurons play an essential role in this sensory activity. Moreover, probably because of their activity, they represent an exception compared to other parts of the brain, since OB interneurons are continuously generated in the postnatal and adult period. In this review, we will focus on periglomerular (PG) cells which are a class of interneurons found in the glomerular layer of the OB. These interneurons can be classified into distinct subtypes based on their neurochemical nature, based on the neurotransmitter and calcium-binding proteins expressed by these cells. Dopaminergic (DA) periglomerular cells and calretinin (CR) cells are among the newly generated interneurons and play an important role in the physiology of OB. In the OB, DA cells are involved in the processing of odors and the adaptation of the bulbar network to external conditions. The main role of DA cells in OB appears to be the inhibition of glutamate release from olfactory sensory fibers. Calretinin cells are probably the best morphologically characterized interneurons among PG cells in OB, but little is known about their function except for their inhibitory effect on noisy random excitatory signals arriving at the main neurons. In this review, we will mainly describe the electrophysiological properties related to the excitability profiles of DA and CR cells, with a particular view on the differences that characterize DA mature interneurons from cells in different stages of adult neurogenesis.
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Affiliation(s)
- Simona Capsoni
- Department of Neuroscience and Rehabilitation, University of Ferrara, Ferrara, Italy
- Bio@SNS Laboratory of Biology, Scuola Normale Superiore, Pisa, Italy
| | - Alex Fogli Iseppe
- Department of Neuroscience and Rehabilitation, University of Ferrara, Ferrara, Italy
| | - Fabio Casciano
- Department of Translational Medicine and LTTA Centre, University of Ferrara, Ferrara, Italy
- Interdepartmental Research Centre for the Study of Multiple Sclerosis and Inflammatory and Degenerative Diseases of the Nervous System, University of Ferrara, Ferrara, Italy
| | - Angela Pignatelli
- Department of Neuroscience and Rehabilitation, University of Ferrara, Ferrara, Italy
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9
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Marymonchyk A, Malvaut S, Saghatelyan A. In vivo live imaging of postnatal neural stem cells. Development 2021; 148:271820. [PMID: 34383894 DOI: 10.1242/dev.199778] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Neural stem cells (NSCs) are maintained in specific regions of the postnatal brain and contribute to its structural and functional plasticity. However, the long-term renewal potential of NSCs and their mode of division remain elusive. The use of advanced in vivo live imaging approaches may expand our knowledge of NSC physiology and provide new information for cell replacement therapies. In this Review, we discuss the in vivo imaging methods used to study NSC dynamics and recent live-imaging results with respect to specific intracellular pathways that allow NSCs to integrate and decode different micro-environmental signals. Lastly, we discuss future directions that may provide answers to unresolved questions regarding NSC physiology.
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Affiliation(s)
- Alina Marymonchyk
- CERVO Brain Research Center, Quebec City, QC, CanadaG1J 2G3.,Department of Psychiatry and Neuroscience, Université Laval, Quebec City, QC, CanadaG1V 0A6
| | - Sarah Malvaut
- CERVO Brain Research Center, Quebec City, QC, CanadaG1J 2G3.,Department of Psychiatry and Neuroscience, Université Laval, Quebec City, QC, CanadaG1V 0A6
| | - Armen Saghatelyan
- CERVO Brain Research Center, Quebec City, QC, CanadaG1J 2G3.,Department of Psychiatry and Neuroscience, Université Laval, Quebec City, QC, CanadaG1V 0A6
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10
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Forest J, Chalençon L, Midroit M, Terrier C, Caillé I, Sacquet J, Benetollo C, Martin K, Richard M, Didier A, Mandairon N. Role of Adult-Born Versus Preexisting Neurons Born at P0 in Olfactory Perception in a Complex Olfactory Environment in Mice. Cereb Cortex 2021; 30:534-549. [PMID: 31216001 DOI: 10.1093/cercor/bhz105] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 03/26/2019] [Accepted: 04/21/2019] [Indexed: 12/11/2022] Open
Abstract
Olfactory perceptual learning is defined as an improvement in the discrimination of perceptually close odorants after passive exposure to these odorants. In mice, simple olfactory perceptual learning involving the discrimination of two odorants depends on an increased number of adult-born neurons in the olfactory bulb, which refines the bulbar output. However, the olfactory environment is complex, raising the question of the adjustment of the bulbar network to multiple discrimination challenges. Perceptual learning of 1 to 6 pairs of similar odorants led to discrimination of all learned odor pairs. Increasing complexity did not increase adult-born neuron survival but enhanced the number of adult-born neurons responding to learned odorants and their spine density. Moreover, only complex learning induced morphological changes in neurons of the granule cell layer born during the first day of life (P0). Selective optogenetic inactivation of either population confirmed functional involvement of adult-born neurons regardless of the enrichment complexity, while preexisting neurons were required for complex discrimination only.
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Affiliation(s)
- Jérémy Forest
- INSERM, U1028; CNRS, UMR5292; Lyon Neuroscience Research Center, Neuroplasticity and Neuropathology of Olfactory Perception Team, Lyon, F-69000, France.,Claude Bernard University Lyon1 and University of Lyon, Lyon F-69000, France
| | - Laura Chalençon
- INSERM, U1028; CNRS, UMR5292; Lyon Neuroscience Research Center, Neuroplasticity and Neuropathology of Olfactory Perception Team, Lyon, F-69000, France.,Claude Bernard University Lyon1 and University of Lyon, Lyon F-69000, France
| | - Maëllie Midroit
- INSERM, U1028; CNRS, UMR5292; Lyon Neuroscience Research Center, Neuroplasticity and Neuropathology of Olfactory Perception Team, Lyon, F-69000, France.,Claude Bernard University Lyon1 and University of Lyon, Lyon F-69000, France
| | - Claire Terrier
- INSERM, U1028; CNRS, UMR5292; Lyon Neuroscience Research Center, Neuroplasticity and Neuropathology of Olfactory Perception Team, Lyon, F-69000, France.,Claude Bernard University Lyon1 and University of Lyon, Lyon F-69000, France
| | - Isabelle Caillé
- Sorbonne Universités, Université Pierre et Marie Curie-Paris 06, Centre National de la Recherche Scientifique, UMR8246, INSERM U1130, Institut de Biologie Paris Seine, Neuroscience Paris Seine, and Sorbonne Paris Cité, Université Paris Diderot-Paris 7, Paris, France
| | - Joëlle Sacquet
- INSERM, U1028; CNRS, UMR5292; Lyon Neuroscience Research Center, Neuroplasticity and Neuropathology of Olfactory Perception Team, Lyon, F-69000, France.,Claude Bernard University Lyon1 and University of Lyon, Lyon F-69000, France
| | - Claire Benetollo
- INSERM, U1028, CNRS, UMR5292, Lyon Neuroscience Research Center, Neurogenetic and Optogenetic Platform, University Lyon 1 and University of Lyon, Lyon F-69000, France
| | - Killian Martin
- INSERM, U1028; CNRS, UMR5292; Lyon Neuroscience Research Center, Neuroplasticity and Neuropathology of Olfactory Perception Team, Lyon, F-69000, France.,Claude Bernard University Lyon1 and University of Lyon, Lyon F-69000, France
| | - Marion Richard
- INSERM, U1028; CNRS, UMR5292; Lyon Neuroscience Research Center, Neuroplasticity and Neuropathology of Olfactory Perception Team, Lyon, F-69000, France.,Claude Bernard University Lyon1 and University of Lyon, Lyon F-69000, France
| | - Anne Didier
- INSERM, U1028; CNRS, UMR5292; Lyon Neuroscience Research Center, Neuroplasticity and Neuropathology of Olfactory Perception Team, Lyon, F-69000, France.,Claude Bernard University Lyon1 and University of Lyon, Lyon F-69000, France
| | - Nathalie Mandairon
- INSERM, U1028; CNRS, UMR5292; Lyon Neuroscience Research Center, Neuroplasticity and Neuropathology of Olfactory Perception Team, Lyon, F-69000, France.,Claude Bernard University Lyon1 and University of Lyon, Lyon F-69000, France
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11
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Gengatharan A, Malvaut S, Marymonchyk A, Ghareghani M, Snapyan M, Fischer-Sternjak J, Ninkovic J, Götz M, Saghatelyan A. Adult neural stem cell activation in mice is regulated by the day/night cycle and intracellular calcium dynamics. Cell 2021; 184:709-722.e13. [PMID: 33482084 DOI: 10.1016/j.cell.2020.12.026] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 08/25/2020] [Accepted: 12/15/2020] [Indexed: 01/06/2023]
Abstract
Neural stem cells (NSCs) in the adult brain transit from the quiescent state to proliferation to produce new neurons. The mechanisms regulating this transition in freely behaving animals are, however, poorly understood. We customized in vivo imaging protocols to follow NSCs for several days up to months, observing their activation kinetics in freely behaving mice. Strikingly, NSC division is more frequent during daylight and is inhibited by darkness-induced melatonin signaling. The inhibition of melatonin receptors affected intracellular Ca2+ dynamics and promoted NSC activation. We further discovered a Ca2+ signature of quiescent versus activated NSCs and showed that several microenvironmental signals converge on intracellular Ca2+ pathways to regulate NSC quiescence and activation. In vivo NSC-specific optogenetic modulation of Ca2+ fluxes to mimic quiescent-state-like Ca2+ dynamics in freely behaving mice blocked NSC activation and maintained their quiescence, pointing to the regulatory mechanisms mediating NSC activation in freely behaving animals.
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Affiliation(s)
- Archana Gengatharan
- CERVO Brain Research Center, Quebec City, QC G1J 2G3, Canada; Université Laval, Quebec City, QC G1V 0A6, Canada
| | - Sarah Malvaut
- CERVO Brain Research Center, Quebec City, QC G1J 2G3, Canada; Université Laval, Quebec City, QC G1V 0A6, Canada
| | - Alina Marymonchyk
- CERVO Brain Research Center, Quebec City, QC G1J 2G3, Canada; Université Laval, Quebec City, QC G1V 0A6, Canada
| | - Majid Ghareghani
- CERVO Brain Research Center, Quebec City, QC G1J 2G3, Canada; Université Laval, Quebec City, QC G1V 0A6, Canada
| | - Marina Snapyan
- CERVO Brain Research Center, Quebec City, QC G1J 2G3, Canada; Université Laval, Quebec City, QC G1V 0A6, Canada
| | - Judith Fischer-Sternjak
- Division of Physiological Genomics, BioMedical Center, Ludwig-Maximilians-Universität München, Munich, Germany; Institute of Stem Cell Research, Helmholtz Center, Munich, Germany
| | - Jovica Ninkovic
- Institute of Stem Cell Research, Helmholtz Center, Munich, Germany; Department of Cell Biology and Anatomy, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Magdalena Götz
- Division of Physiological Genomics, BioMedical Center, Ludwig-Maximilians-Universität München, Munich, Germany; Institute of Stem Cell Research, Helmholtz Center, Munich, Germany; Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Armen Saghatelyan
- CERVO Brain Research Center, Quebec City, QC G1J 2G3, Canada; Université Laval, Quebec City, QC G1V 0A6, Canada.
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12
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Developmental Potential and Plasticity of Olfactory Epithelium Stem Cells Revealed by Heterotopic Grafting in the Adult Brain. Stem Cell Reports 2020; 14:692-702. [PMID: 32243847 PMCID: PMC7160358 DOI: 10.1016/j.stemcr.2020.03.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 03/05/2020] [Accepted: 03/06/2020] [Indexed: 12/12/2022] Open
Abstract
The neural stem cells (NSCs) residing in the olfactory epithelium (OE) regenerate damaged olfactory sensory neurons throughout adulthood. The accessibility and availability of these NSCs in living individuals, including humans, makes them a promising candidate for harvesting their potential for cell replacement therapies. However, this requires an in-depth understanding of their developmental potential after grafting. Here, we investigated the developmental potential and plasticity of mouse OE-derived NSCs after grafting into the adult subventricular zone (SVZ) neurogenic niche. Our results showed that OE-derived NSCs integrate and proliferate just like endogenous SVZ stem cells, migrate with similar dynamics as endogenous neuroblasts toward the olfactory bulb, and mature and acquire similar electrophysiological properties as endogenous adult-born bulbar interneurons. These results reveal the developmental potential and plasticity of OE-derived NSCs in vivo and show that they can respond to heterotopic neurogenic cues to adapt their phenotype and become functional neurons in ectopic brain regions. OE-derived NSCs integrate in the SVZ after heterotopic transplantation OE-derived NSCs respond to SVZ niche factors and change their developmental program The development of OE-derived and SVZ NSCs are indistinguishable OE-derived NSCs grafted into the SVZ become functional bulbar interneurons
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13
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Static Magnetic Field Exposure In Vivo Enhances the Generation of New Doublecortin-expressing Cells in the Sub-ventricular Zone and Neocortex of Adult Rats. Neuroscience 2019; 425:217-234. [PMID: 31809729 DOI: 10.1016/j.neuroscience.2019.11.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 11/01/2019] [Accepted: 11/04/2019] [Indexed: 01/28/2023]
Abstract
Static magnetic field (SMF) is gaining interest as a potential technique for modulating CNS neuronal activity. Previous studies have shown a pro-neurogenic effect of short periods of extremely low frequency pulsatile magnetic fields (PMF) in vivo and pro-survival effect of low intensity SMF in cultured neurons in vitro, but little is known about the in vivo effects of low to moderate intensity SMF on brain functions. We investigated the effect of continuously-applied SMF on subventricular zone (SVZ) neurogenesis and immature doublecortin (DCX)-expressing cells in the neocortex of young adult rats and in primary cultures of cortical neurons in vitro. A small (3 mm diameter) magnetic disc was implanted on the skull of rats at bregma, producing an average field strength of 4.3 mT at SVZ and 12.9 mT at inner neocortex. Levels of proliferation of SVZ stem cells were determined by 5-ethynyl-2'-deoxyuridine (EdU) labelling, and early neuronal phenotype development was determined by expression of doublecortin (DCX). To determine the effect of SMF on neurogenesis in vitro, permanent magnets were placed beneath the culture dishes. We found that low intensity SMF exposure enhances cell proliferation in SVZ and new DCX-expressing cells in neocortical regions of young adult rats. In primary cortical neuronal cultures, SMF exposure increased the expression of newly generated cells co-labelled with EdU and DCX or the mature neuronal marker NeuN, while activating a set of pro neuronal bHLH genes. SMF exposure has potential for treatment of neurodegenerative disease and conditions such as CNS trauma and affective disorders in which increased neurogenesis is desirable.
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Fujioka T, Kaneko N, Sawamoto K. Blood vessels as a scaffold for neuronal migration. Neurochem Int 2019; 126:69-73. [PMID: 30851365 DOI: 10.1016/j.neuint.2019.03.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 02/27/2019] [Accepted: 03/02/2019] [Indexed: 12/19/2022]
Abstract
Neurogenesis and angiogenesis share regulatory factors that contribute to the formation of vascular networks and neuronal circuits in the brain. While crosstalk mechanisms between neural stem cells (NSCs) and the vasculature have been extensively investigated, recent studies have provided evidence that blood vessels also play an essential role in neuronal migration in the brain during development and regeneration. The mechanisms of the neuronal migration along blood vessels, referred to as "vascular-guided migration," are now being elucidated. The vascular endothelial cells secrete soluble factors that attract and promote neuronal migration in collaboration with astrocytes that enwrap the blood vessels. In addition, especially in the adult brain, the blood vessels serve as a migration scaffold for adult-born immature neurons generated in the ventricular-subventricular zone (V-SVZ), a germinal zone surrounding the lateral ventricles. The V-SVZ-derived immature neurons use the vascular scaffold to assist their migration toward an injured area after ischemic stroke, and contribute to neuronal regeneration. Here we review the current knowledge about the role of vasculature in neuronal migration and the molecular mechanisms controlling this process. While most of this research has been done in rodents, a comprehensive understanding of vasculature-guided neuronal migration could contribute to new therapeutic approaches for increasing new neurons in the brain after injury.
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Affiliation(s)
- Teppei Fujioka
- Department of Developmental and Regenerative Biology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, 467-8601, Japan; Department of Neurology and Neuroscience, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, 467-8601, Japan
| | - Naoko Kaneko
- Department of Developmental and Regenerative Biology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, 467-8601, Japan
| | - Kazunobu Sawamoto
- Department of Developmental and Regenerative Biology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, 467-8601, Japan; Division of Neural Development and Regeneration, National Institute for Physiological Sciences, Okazaki, Aichi, 444-8585, Japan.
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Fanibunda SE, Desouza LA, Kapoor R, Vaidya RA, Vaidya VA. Thyroid Hormone Regulation of Adult Neurogenesis. VITAMINS AND HORMONES 2018; 106:211-251. [DOI: 10.1016/bs.vh.2017.04.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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16
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Miranda-Martínez A, Mercado-Gómez OF, Arriaga-Ávila V, Guevara-Guzmán R. Distribution of Adiponectin Receptors 1 and 2 in the Rat Olfactory Bulb and the Effect of Adiponectin Injection on Insulin Receptor Expression. Int J Endocrinol 2017; 2017:4892609. [PMID: 29463982 PMCID: PMC5804105 DOI: 10.1155/2017/4892609] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 11/08/2017] [Accepted: 11/14/2017] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Adiponectin (APN) is an adipocyte-derived hormone that has peripheral beneficial effects. Although its receptors AdipoR1 and AdipoR2 are expressed in the brain, their function in neurons is poorly understood. The aims of this work were to describe the distribution of APN receptors in the olfactory bulb (OB) as well as the possible effects of APN injection on the insulin receptor (InsR) content and Akt kinase. METHOD We performed the double immunofluorescence technique to describe the distribution of AdipoRs and the cellular type they were expressing. mRNA transcript and protein content were assessed by RT-PCR and Western blot, respectively. APN injection was performed to analyze its possible effect on the insulin pathway. RESULTS We found that AdipoRs were localized in all cell layers and in both neurons and astrocytes. We observed the presence of mRNA transcripts and immunoblot analysis confirmed the protein on the intact OB; APN injection in the OB resulted in a slight decrease of the total InsR and Akt phosphorylation and a reduction of phopho-InsR content. CONCLUSIONS These data demonstrated that AdipoRs are expressed in OB regions, and APN injection could act as an insulin pathway modulator in the OB and thus possibly contribute to olfaction physiology.
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Affiliation(s)
- Alfredo Miranda-Martínez
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, Del. Coyoacán, 04510 Ciudad de México, Mexico
- Programa de Doctorado en Ciencias Biológicas, Coordinación del Posgrado en Ciencias Biológicas, Edificio B, 1° Piso. Circuito de Posgrados, Ciudad Universitaria, Del. Coyoacán, 04510 Ciudad de México, Mexico
| | - Octavio Fabián Mercado-Gómez
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, Del. Coyoacán, 04510 Ciudad de México, Mexico
| | - Virginia Arriaga-Ávila
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, Del. Coyoacán, 04510 Ciudad de México, Mexico
| | - Rosalinda Guevara-Guzmán
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, Del. Coyoacán, 04510 Ciudad de México, Mexico
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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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Malvaut S, Gribaudo S, Hardy D, David LS, Daroles L, Labrecque S, Lebel-Cormier MA, Chaker Z, Coté D, De Koninck P, Holzenberger M, Trembleau A, Caille I, Saghatelyan A. CaMKIIα Expression Defines Two Functionally Distinct Populations of Granule Cells Involved in Different Types of Odor Behavior. Curr Biol 2017; 27:3315-3329.e6. [PMID: 29107547 DOI: 10.1016/j.cub.2017.09.058] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 08/23/2017] [Accepted: 09/27/2017] [Indexed: 12/25/2022]
Abstract
Granule cells (GCs) in the olfactory bulb (OB) play an important role in odor information processing. Although they have been classified into various neurochemical subtypes, the functional roles of these subtypes remain unknown. We used in vivo two-photon Ca2+ imaging combined with cell-type-specific identification of GCs in the mouse OB to examine whether functionally distinct GC subtypes exist in the bulbar network. We showed that half of GCs express Ca2+/calmodulin-dependent protein kinase IIα (CaMKIIα+) and that these neurons are preferentially activated by olfactory stimulation. The higher activity of CaMKIIα+ neurons is due to the weaker inhibitory input that they receive compared to their CaMKIIα-immunonegative (CaMKIIα-) counterparts. In line with these functional data, immunohistochemical analyses showed that 75%-90% of GCs expressing the immediate early gene cFos are CaMKIIα+ in naive animals and in mice that have been exposed to a novel odor and go/no-go operant conditioning, or that have been subjected to long-term associative memory and spontaneous habituation/dishabituation odor discrimination tasks. On the other hand, a perceptual learning task resulted in increased activation of CaMKIIα- cells. Pharmacogenetic inhibition of CaMKIIα+ GCs revealed that this subtype is involved in habituation/dishabituation and go/no-go odor discrimination, but not in perceptual learning. In contrast, pharmacogenetic inhibition of GCs in a subtype-independent manner affected perceptual learning. Our results indicate that functionally distinct populations of GCs exist in the OB and that they play distinct roles during different odor tasks.
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Affiliation(s)
- Sarah Malvaut
- CERVO Brain Research Center, Quebec City, QC G1J 2G3, Canada
| | - Simona Gribaudo
- Sorbonne Universités, UPMC Université Paris 06, INSERM, CNRS, Institut de Biologie Paris Seine, Neuroscience Paris Seine, 75005 Paris, France
| | - Delphine Hardy
- CERVO Brain Research Center, Quebec City, QC G1J 2G3, Canada
| | | | - Laura Daroles
- Sorbonne Universités, UPMC Université Paris 06, INSERM, CNRS, Institut de Biologie Paris Seine, Neuroscience Paris Seine, 75005 Paris, France
| | - Simon Labrecque
- CERVO Brain Research Center, Quebec City, QC G1J 2G3, Canada
| | | | - Zayna Chaker
- INSERM and Sorbonne Universités, UPMC, Centre de Recherche Saint-Antoine, Paris, France
| | - Daniel Coté
- CERVO Brain Research Center, Quebec City, QC G1J 2G3, Canada; Faculté des Sciences et de Génie, Université Laval, Quebec City, QC G1V 0A6, Canada
| | - Paul De Koninck
- CERVO Brain Research Center, Quebec City, QC G1J 2G3, Canada; Faculté des Sciences et de Génie, Université Laval, Quebec City, QC G1V 0A6, Canada
| | - Martin Holzenberger
- INSERM and Sorbonne Universités, UPMC, Centre de Recherche Saint-Antoine, Paris, France
| | - Alain Trembleau
- Sorbonne Universités, UPMC Université Paris 06, INSERM, CNRS, Institut de Biologie Paris Seine, Neuroscience Paris Seine, 75005 Paris, France
| | - Isabelle Caille
- Sorbonne Universités, UPMC Université Paris 06, INSERM, CNRS, Institut de Biologie Paris Seine, Neuroscience Paris Seine, 75005 Paris, France; Université Paris Diderot, Sorbonne Paris Cité, 75013 Paris, France.
| | - 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.
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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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Petri R, Pircs K, Jönsson ME, Åkerblom M, Brattås PL, Klussendorf T, Jakobsson J. let-7 regulates radial migration of new-born neurons through positive regulation of autophagy. EMBO J 2017; 36:1379-1391. [PMID: 28336683 DOI: 10.15252/embj.201695235] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 02/23/2017] [Accepted: 03/01/2017] [Indexed: 01/22/2023] Open
Abstract
During adult neurogenesis, newly formed olfactory bulb (OB) interneurons migrate radially to integrate into specific layers of the OB Despite the importance of this process, the intracellular mechanisms that regulate radial migration remain poorly understood. Here, we find that microRNA (miRNA) let-7 regulates radial migration by modulating autophagy in new-born neurons. Using Argonaute2 immunoprecipitation, we performed global profiling of miRNAs in adult-born OB neurons and identified let-7 as a highly abundant miRNA family. Knockdown of let-7 in migrating neuroblasts prevented radial migration and led to an immature morphology of newly formed interneurons. This phenotype was accompanied by a decrease in autophagic activity. Overexpression of Beclin-1 or TFEB in new-born neurons lacking let-7 resulted in re-activation of autophagy and restored radial migration. Thus, these results reveal a miRNA-dependent link between autophagy and adult neurogenesis with implications for neurodegenerative diseases where these processes are impaired.
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Affiliation(s)
- Rebecca Petri
- Laboratory of Molecular Neurogenetics, Department of Experimental Medical Science, Wallenberg Neuroscience Center and Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Karolina Pircs
- Laboratory of Molecular Neurogenetics, Department of Experimental Medical Science, Wallenberg Neuroscience Center and Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Marie E Jönsson
- Laboratory of Molecular Neurogenetics, Department of Experimental Medical Science, Wallenberg Neuroscience Center and Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Malin Åkerblom
- Laboratory of Molecular Neurogenetics, Department of Experimental Medical Science, Wallenberg Neuroscience Center and Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Per Ludvik Brattås
- Laboratory of Molecular Neurogenetics, Department of Experimental Medical Science, Wallenberg Neuroscience Center and Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Thies Klussendorf
- Laboratory of Molecular Neurogenetics, Department of Experimental Medical Science, Wallenberg Neuroscience Center and Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Johan Jakobsson
- Laboratory of Molecular Neurogenetics, Department of Experimental Medical Science, Wallenberg Neuroscience Center and Lund Stem Cell Center, Lund University, Lund, Sweden
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Pignatelli A, Belluzzi O. Dopaminergic Neurones in the Main Olfactory Bulb: An Overview from an Electrophysiological Perspective. Front Neuroanat 2017; 11:7. [PMID: 28261065 PMCID: PMC5306133 DOI: 10.3389/fnana.2017.00007] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 02/02/2017] [Indexed: 02/03/2023] Open
Abstract
The olfactory bulb (OB), the first center processing olfactory information, is characterized by a vigorous life-long activity-dependent plasticity responsible for a variety of odor-evoked behavioral responses. It hosts the more numerous group of dopaminergic (DA) neurones in the central nervous system, cells strategically positioned at the entry of the bulbar circuitry, directly in contact with the olfactory nerve terminals, which play a key role in odor processing and in the adaptation of the bulbar network to external conditions. Here, we focus mainly on the electrophysiological properties of DA interneurones, reviewing findings concerning their excitability profiles in adulthood and in different phases of adult neurogenesis. We also discuss dynamic changes of the DA interneurones related to environmental stimuli and their possible functional implications.
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Affiliation(s)
- Angela Pignatelli
- Life Sciences and Biotechnology, University of Ferrara Ferrara, Italy
| | - Ottorino Belluzzi
- Life Sciences and Biotechnology, University of Ferrara Ferrara, Italy
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