1
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Puche AC, Hook C, Zhou FW. Cell type-specific and frequency-dependent centrifugal modulation in olfactory bulb output neurons in vivo. J Neurophysiol 2024; 131:1226-1239. [PMID: 38691531 DOI: 10.1152/jn.00078.2024] [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: 02/22/2024] [Revised: 04/11/2024] [Accepted: 04/25/2024] [Indexed: 05/03/2024] Open
Abstract
Mitral/tufted cells (M/TCs) form complex local circuits with interneurons in the olfactory bulb and are powerfully inhibited by these interneurons. The horizontal limb of the diagonal band of Broca (HDB), the only GABAergic/inhibitory source of centrifugal circuit with the olfactory bulb, is known to target olfactory bulb interneurons, and we have shown targeting also to olfactory bulb glutamatergic neurons in vitro. However, the net efficacy of these circuits under different patterns of activation in vivo and the relative balance between the various targeted intact local and centrifugal circuits was the focus of this study. Here channelrhodopsin-2 (ChR2) was expressed in HDB GABAergic neurons to investigate the short-term plasticity of HDB-activated disinhibitory rebound excitation of M/TCs. Optical activation of HDB interneurons increased spontaneous M/TC firing without odor presentation and increased odor-evoked M/TC firing. HDB activation induced disinhibitory rebound excitation (burst or cluster of spiking) in all classes of M/TCs. This excitation was frequency dependent, with short-term facilitation only at higher HDB stimulation frequency (5 Hz and above). However, frequency-dependent HDB regulation was more potent in the deeper layer M/TCs compared with more superficial layer M/TCs. In all neural circuits the balance between inhibition and excitation in local and centrifugal circuits plays a critical functional role, and this patterned input-dependent regulation of inhibitory centrifugal inputs to the olfactory bulb may help maintain the precise balance across the populations of output neurons in different environmental odors, putatively to sharpen the enhancement of tuning specificity of individual or classes of M/TCs to odors.NEW & NOTEWORTHY Neuronal local circuits in the olfactory bulb are modulated by centrifugal long circuits. In vivo study here shows that inhibitory horizontal limb of the diagonal band of Broca (HDB) modulates all five types of mitral/tufted cells (M/TCs), by direct inhibitory circuits HDB → M/TCs and indirect disinhibitory long circuits HDB → interneurons → M/TCs. The HDB net effect exerts excitation in all types of M/TCs but more powerful in deeper layer output neurons as HDB activation frequency increases, which may sharpen the tuning specificity of classes of M/TCs to odors during sensory processing.
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Affiliation(s)
- Adam C Puche
- Department of Anatomy and Neurobiology, Program in Neurosciences, University of Maryland School of Medicine, Baltimore, Maryland, United States
| | - Chelsea Hook
- Department of Anatomy and Neurobiology, Program in Neurosciences, University of Maryland School of Medicine, Baltimore, Maryland, United States
| | - Fu-Wen Zhou
- Department of Anatomy and Neurobiology, Program in Neurosciences, University of Maryland School of Medicine, Baltimore, Maryland, United States
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2
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Goodkey K, Wischmeijer A, Perrin L, Watson AES, Qureshi L, Cordelli DM, Toni F, Gnazzo M, Benedicenti F, Elmaleh-Bergès M, Low KJ, Voronova A. Olfactory bulb anomalies in KBG syndrome mouse model and patients. BMC Med 2024; 22:158. [PMID: 38616269 PMCID: PMC11017579 DOI: 10.1186/s12916-024-03363-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 03/18/2024] [Indexed: 04/16/2024] Open
Abstract
ANKRD11 (ankyrin repeat domain 11) is a chromatin regulator and the only gene associated with KBG syndrome, a rare neurodevelopmental disorder. We have previously shown that Ankrd11 regulates murine embryonic cortical neurogenesis. Here, we show a novel olfactory bulb phenotype in a KBG syndrome mouse model and two diagnosed patients. Conditional knockout of Ankrd11 in murine embryonic neural stem cells leads to aberrant postnatal olfactory bulb development and reduced size due to reduction of the olfactory bulb granule cell layer. We further show that the rostral migratory stream has incomplete migration of neuroblasts, reduced cell proliferation as well as aberrant differentiation of neurons. This leads to reduced neuroblasts and neurons in the olfactory bulb granule cell layer. In vitro, Ankrd11-deficient neural stem cells from the postnatal subventricular zone display reduced migration, proliferation, and neurogenesis. Finally, we describe two clinically and molecularly confirmed KBG syndrome patients with anosmia and olfactory bulb and groove hypo-dysgenesis/agenesis. Our report provides evidence that Ankrd11 is a novel regulator of olfactory bulb development and neuroblast migration. Moreover, our study highlights a novel clinical sign of KBG syndrome linked to ANKRD11 perturbations in mice and humans.
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Affiliation(s)
- Kara Goodkey
- Department of Medical Genetics, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB, T6G 2H7, Canada
- Women and Children's Health Research Institute, University of Alberta, 5-083 Edmonton Clinic Health Academy, Edmonton, AB, T6G 1C9, Canada
| | - Anita Wischmeijer
- Clinical Genetics Service and Coordination Center for Rare Diseases, Department of Pediatrics, Regional Hospital of Bolzano, Bolzano, Italy
| | | | - Adrianne E S Watson
- Department of Medical Genetics, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB, T6G 2H7, Canada
- Women and Children's Health Research Institute, University of Alberta, 5-083 Edmonton Clinic Health Academy, Edmonton, AB, T6G 1C9, Canada
| | - Leenah Qureshi
- Department of Medical Genetics, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB, T6G 2H7, Canada
| | - Duccio Maria Cordelli
- IRCCS Istituto Delle Scienze Neurologiche Di Bologna, UOC Neuropsichiatria Dell'età Pediatrica, Bologna, Italy
| | - Francesco Toni
- IRCCS Istituto Delle Scienze Neurologiche Di Bologna, Programma Di Neuroradiologia Con Tecniche Ad Elevata Complessità (PNTEC), Bologna, Italy
| | - Maria Gnazzo
- Laboratory of Medical Genetics, Translational Cytogenomics Research Unit, Bambino Gesù Children's Hospital, IRCCS, 00165, Rome, Italy
| | - Francesco Benedicenti
- Clinical Genetics Service and Coordination Center for Rare Diseases, Department of Pediatrics, Regional Hospital of Bolzano, Bolzano, Italy
| | | | - Karen J Low
- Department of Academic Child Health, Bristol Medical School, Population Health Sciences, University of Bristol, Bristol, UK
- Clinical Genetics Service, St. Michaels Hospital, Bristol, UK
| | - Anastassia Voronova
- Department of Medical Genetics, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB, T6G 2H7, Canada.
- Women and Children's Health Research Institute, University of Alberta, 5-083 Edmonton Clinic Health Academy, Edmonton, AB, T6G 1C9, Canada.
- Department of Cell Biology, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB, T6G 2H7, Canada.
- Faculty of Medicine & Dentistry, Neuroscience and Mental Health Institute, Edmonton, AB, T6G 2E1, Canada.
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3
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Troppoli TA, Yang C, Katsuki F, Uygun DS, Lin I, Aguilar D, Spratt T, Basheer R, McNally JM, Chan CS, McKenna JT, Brown RE. Neuronal PAS domain 1 identifies a major subpopulation of wakefulness-promoting GABAergic neurons in basal forebrain. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.09.566065. [PMID: 37986953 PMCID: PMC10659409 DOI: 10.1101/2023.11.09.566065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Here we describe a novel group of basal forebrain (BF) neurons expressing neuronal PAS domain 1 (Npas1), a developmental transcription factor linked to neuropsychiatric disorders. Immunohistochemical staining in Npas1-cre-2A-TdTomato mice revealed BF Npas1 + neurons are distinct from well-studied parvalbumin or cholinergic neurons. Npas1 staining in GAD67-GFP knock-in mice confirmed that the vast majority of Npas1 + neurons are GABAergic, with minimal colocalization with glutamatergic neurons in vGlut1-cre-tdTomato or vGlut2-cre-tdTomato mice. The density of Npas1 + neurons was high, 5-6 times that of neighboring cholinergic, parvalbumin or glutamatergic neurons. Anterograde tracing identified prominent projections of BF Npas1 + neurons to brain regions involved in sleep-wake control, motivated behaviors and olfaction such as the lateral hypothalamus, lateral habenula, nucleus accumbens shell, ventral tegmental area and olfactory bulb. Chemogenetic activation of BF Npas1 + neurons in the light (inactive) period increased the amount of wakefulness and the latency to sleep for 2-3 hr, due to an increase in long wake bouts and short NREM sleep bouts. Non-REM slow-wave (0-1.5 Hz) and sigma (9-15 Hz) power, as well as sleep spindle density, amplitude and duration, were reduced, reminiscent of findings in several neuropsychiatric disorders. Together with previous findings implicating BF Npas1 + neurons in stress responsiveness, the anatomical projections of BF Npas1 + neurons and the effect of activating them suggest a possible role for BF Npas1 + neurons in motivationally-driven wakefulness and stress-induced insomnia. Identification of this major subpopulation of BF GABAergic neurons will facilitate studies of their role in sleep disorders, dementia and other neuropsychiatric conditions involving BF. SIGNIFICANCE STATEMENT We characterize a group of basal forebrain (BF) neurons in the mouse expressing neuronal PAS domain 1 (Npas1), a developmental transcription factor linked to neuropsychiatric disorders. BF Npas1 + neurons are a major subset of GABAergic neurons distinct and more numerous than cholinergic, parvalbumin or glutamate neurons. BF Npas1 + neurons target brain areas involved in arousal, motivation and olfaction. Activation of BF Npas1 + neurons in the light (inactive) period increased wakefulness and the latency to sleep due to increased long wake bouts. Non-REM sleep slow waves and spindles were reduced reminiscent of findings in several neuropsychiatric disorders. Identification of this major subpopulation of BF GABAergic wake-promoting neurons will allow studies of their role in insomnia, dementia and other conditions involving BF.
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Brand G, Bontempi C, Jacquot L. Impact of deep brain stimulation (DBS) on olfaction in Parkinson's disease: Clinical features and functional hypotheses. Rev Neurol (Paris) 2023; 179:947-954. [PMID: 37301657 DOI: 10.1016/j.neurol.2022.12.013] [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: 09/30/2022] [Revised: 11/17/2022] [Accepted: 12/22/2022] [Indexed: 06/12/2023]
Abstract
Deep brain stimulation (DBS) is a surgical therapy typically applied in Parkinson's disease (PD). The efficacity of DBS on the control of motor symptoms in PD is well grounded while the efficacity on non-motor symptoms is more controversial, especially on olfactory disorders (ODs). The present review shows that DBS does not improve hyposmia but can affect positively identification/discrimination scores in PD. The functional hypotheses suggest complex mechanisms in terms of cerebral connectivity and neurogenesis process which could act indirectly on the olfactory bulb and olfactory pathways related to specific cognitive olfactory tasks. The functional hypotheses also suggest complex mechanisms of cholinergic neurotransmitter interactions involved in these pathways. Finally, the impact of DBS on general cognitive functions in PD could also be beneficial to identification/discrimination tasks in PD.
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Affiliation(s)
- G Brand
- Neuroscience Laboratory, University of Franche-Comte, Besançon, France.
| | - C Bontempi
- Neuroscience Laboratory, University of Franche-Comte, Besançon, France
| | - L Jacquot
- Neuroscience Laboratory, University of Franche-Comte, Besançon, France
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5
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Bowers JM, Li CY, Parker CG, Westbrook ME, Juntti SA. Pheromone Perception in Fish: Mechanisms and Modulation by Internal Status. Integr Comp Biol 2023; 63:407-427. [PMID: 37263784 PMCID: PMC10445421 DOI: 10.1093/icb/icad049] [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: 02/28/2023] [Revised: 05/24/2023] [Accepted: 05/27/2023] [Indexed: 06/03/2023] Open
Abstract
Pheromones are chemical signals that facilitate communication between animals, and most animals use pheromones for reproduction and other forms of social behavior. The identification of key ligands and olfactory receptors used for pheromonal communication provides insight into the sensory processing of these important cues. An individual's responses to pheromones can be plastic, as physiological status modulates behavioral outputs. In this review, we outline the mechanisms for pheromone sensation and highlight physiological mechanisms that modify pheromone-guided behavior. We focus on hormones, which regulate pheromonal communication across vertebrates including fish, amphibians, and rodents. This regulation may occur in peripheral olfactory organs and the brain, but the mechanisms remain unclear. While this review centers on research in fish, we will discuss other systems to provide insight into how hormonal mechanisms function across taxa.
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Affiliation(s)
- Jessica M Bowers
- Department of Biology, University of Maryland, 2128 Bioscience Research Bldg, College Park, MD 20742, USA
| | - Cheng-Yu Li
- Department of Biology, University of Maryland, 2128 Bioscience Research Bldg, College Park, MD 20742, USA
| | - Coltan G Parker
- Department of Biology, University of Maryland, 2128 Bioscience Research Bldg, College Park, MD 20742, USA
| | - Molly E Westbrook
- Department of Biology, University of Maryland, 2128 Bioscience Research Bldg, College Park, MD 20742, USA
| | - Scott A Juntti
- Department of Biology, University of Maryland, 2128 Bioscience Research Bldg, College Park, MD 20742, USA
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6
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Venegas JP, Navarrete M, Orellana-Garcia L, Rojas M, Avello-Duarte F, Nunez-Parra A. Basal Forebrain Modulation of Olfactory Coding In Vivo. Int J Psychol Res (Medellin) 2023; 16:62-86. [PMID: 38106956 PMCID: PMC10723750 DOI: 10.21500/20112084.6486] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 08/23/2022] [Accepted: 12/07/2022] [Indexed: 12/19/2023] Open
Abstract
Sensory perception is one of the most fundamental brain functions, allowing individuals to properly interact and adapt to a constantly changing environment. This process requires the integration of bottom-up and topdown neuronal activity, which is centrally mediated by the basal forebrain, a brain region that has been linked to a series of cognitive processes such as attention and alertness. Here, we review the latest research using optogenetic approaches in rodents and in vivo electrophysiological recordings that are shedding light on the role of this region, in regulating olfactory processing and decisionmaking. Moreover, we summarize evidence highlighting the anatomical and physiological differences in the basal forebrain of individuals with autism spectrum disorder, which could underpin the sensory perception abnormalities they exhibit, and propose this research line as a potential opportunity to understand the neurobiological basis of this disorder.
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Affiliation(s)
- Juan Pablo Venegas
- Physiology Laboratory, Biology Department, Faculty of Science, University of Chile, Chile.Universidad de ChileUniversity of ChileChile
| | - Marcela Navarrete
- Physiology Laboratory, Biology Department, Faculty of Science, University of Chile, Chile.Universidad de ChileUniversity of ChileChile
| | - Laura Orellana-Garcia
- Physiology Laboratory, Biology Department, Faculty of Science, University of Chile, Chile.Universidad de ChileUniversity of ChileChile
| | - Marcelo Rojas
- Physiology Laboratory, Biology Department, Faculty of Science, University of Chile, Chile.Universidad de ChileUniversity of ChileChile
| | - Felipe Avello-Duarte
- Physiology Laboratory, Biology Department, Faculty of Science, University of Chile, Chile.Universidad de ChileUniversity of ChileChile
| | - Alexia Nunez-Parra
- Physiology Laboratory, Biology Department, Faculty of Science, University of Chile, Chile.Universidad de ChileUniversity of ChileChile
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7
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Zhou FW, Hook C, Puche AC. Frequency-dependent centrifugal modulation of the activity of different classes of mitral and tufted cells in olfactory bulb. J Neurophysiol 2023; 129:1515-1533. [PMID: 37222431 PMCID: PMC10281792 DOI: 10.1152/jn.00390.2022] [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: 09/14/2022] [Revised: 05/22/2023] [Accepted: 05/22/2023] [Indexed: 05/25/2023] Open
Abstract
Mitral/tufted cells (M/TCs), the principal output neuron classes form complex circuits with bulbar neurons and long-range centrifugal circuits with higher processing areas such as the horizontal limb of the diagonal band of Broca (HDB). The precise excitability of output neurons is sculpted by local inhibitory circuits. Here, light-gated cation channel channelrhodopsin-2 (ChR2) was expressed in HDB GABAergic neurons to investigate the short-term plasticity of evoked postsynaptic currents/potentials of HDB input to all classes of M/TCs and effects on firing in the acute slice preparation. Activation of the HDB directly inhibited all classes of output neurons exhibiting frequency-dependent short-term depression of evoked inhibitory postsynaptic current (eIPSC)/potential (eIPSP), resulting in decreased inhibition of responses to olfactory nerve input as a function of input frequency. In contrast, activation of an indirect circuit of HDB→interneurons→M/TCs induced frequency-dependent disinhibition, resulting in short-term facilitation of evoked excitatory postsynaptic current (eEPSC) eliciting a burst or cluster of spiking in M/TCs. The facilitatory effects of elevated HDB input frequency were strongest on deeper output neurons (deep tufted and mitral cells) and negligible on peripheral output neurons (external and superficial tufted cells). Taken together, GABAergic HDB activation generates frequency-dependent regulation that differentially affects the excitability and responses across the five classes of M/TCs. This regulation may help maintain the precise balance between inhibition and excitation of neuronal circuits across the populations of output neurons in the face of changes in an animal sniffing rate, putatively to enhance and sharpen the tuning specificity of individual or classes of M/TCs to odors.NEW & NOTEWORTHY Neuronal circuits in the olfactory bulb closely modulate olfactory bulb output activity. Activation of GABAergic circuits from the HDB to the olfactory bulb has both direct and indirect action differentially across the five classes of M/TC bulbar output neurons. The net effect enhances the excitability of deeper output neurons as HDB frequency increases, altering the relative inhibition-excitation balance of output circuits. We hypothesize that this sharpens the tuning specificity of classes of M/TCs to odors during sensory processing.
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Affiliation(s)
- Fu-Wen Zhou
- Department of Neurobiology, Program in Neurosciences, University of Maryland School of Medicine, Baltimore, Maryland, United States
| | - Chelsea Hook
- Department of Neurobiology, Program in Neurosciences, University of Maryland School of Medicine, Baltimore, Maryland, United States
| | - Adam C Puche
- Department of Neurobiology, Program in Neurosciences, University of Maryland School of Medicine, Baltimore, Maryland, United States
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8
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Hook C, Puche AC. Bulbar projecting subcortical GABAergic neurons send collateral branches extensively and selectively to primary olfactory cortical regions. J Comp Neurol 2023; 531:451-460. [PMID: 36463397 PMCID: PMC9795336 DOI: 10.1002/cne.25434] [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: 07/06/2022] [Revised: 09/26/2022] [Accepted: 10/27/2022] [Indexed: 12/05/2022]
Abstract
Circuit operations of the olfactory bulb are modulated by higher order projections from multiple regions, many of which are themselves targets of bulbar output. Multiple glutamatergic regions project to the olfactory bulb, including the anterior olfactory nucleus (AON), prefrontal cortex (PFC), piriform cortex (PC), entorhinal cortex (EC), and tenia tecta (TT). In contrast, only one region provides GABAergic projections to the bulb. These GABA neurons are located in the horizontal limb of the diagonal band of Broca extending posteriorly through the magnocellular preoptic nucleus to the nucleus of the lateral olfactory bulb. However, it was unclear whether bulbar projecting GABAergic neurons collaterallize projecting to other brain regions. To address this, we mapped collateral projections from bulbar projecting GABAergic neurons using intersectional strategies of viral and traditional tract tracers. This approach revealed bulbar projecting GABAergic neurons show remarkable specificity targeting other primary olfactory cortical regions exhibiting abundant collateral projections into the accessory olfactory bulb, AON, PFC, PC, and TT. The only "nonolfactory" region receiving collateral projections was sparse connectivity to the medial prefrontal orbital cortex. This suggests that basal forebrain inhibitory feedback also modulates glutamatergic feedback areas that are themselves prominent bulbar projection regions. Thus, inhibitory feedback may be simultaneously modulating both synaptic processing of olfactory information in the bulb and associational processing of olfactory information from primary olfactory cortex. We hypothesize that these olfactory GABAergic feedback neurons are a regulator of the entire olfactory system.
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Affiliation(s)
- Chelsea Hook
- Department of Anatomy & Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Adam C Puche
- Department of Anatomy & Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
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9
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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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10
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Huang L, Zhang W, Han Y, Tang Y, Zhou W, Liu G, Shi W. Anti-Depressant Fluoxetine Hampers Olfaction of Goldfish by Interfering with the Initiation, Transmission, and Processing of Olfactory Signals. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:15848-15859. [PMID: 36260920 DOI: 10.1021/acs.est.2c02987] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The ubiquitous presence of fluoxetine (FLX) in aquatic environments poses great threat to fish species. However, little is known about its deleterious impacts on fish olfaction. In this study, the olfactory toxicity of FLX at environmentally realistic levels was assessed by monitoring the behavioral and electroolfactogram (EOG) responses to olfactory stimuli with goldfish (Carassius auratus), and the toxification mechanisms underlying the observed olfaction dysfunction were also investigated. Our results showed that the behavioral and EOG responses of goldfish to olfactory stimuli were significantly weakened by FLX, indicating an evident toxicity of FLX to olfaction. Moreover, FLX exposure led to significant alterations in olfactory initiation-related genes, suppression of ion pumps (Ca2+-ATPase and Na+/K+-ATPase), tissue lesions, and fewer olfactory sensory neurons in olfactory epithelium. In addition to altering the expression of olfactory transmission-related genes, comparative metabolomic analysis found that olfaction-related neurotransmitters (i.e., l-glutamate and acetylcholine) and the olfactory transduction pathway were significantly affected by FLX. Furthermore, evident tissue lesions, aggravated lipid peroxidation and apoptosis, and less neuropeptide Y were observed in the olfactory bulbs of FLX-exposed goldfish. Our findings indicate that FLX may hamper goldfish olfaction by interfering with the initiation, transmission, and processing of olfactory signals.
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Affiliation(s)
- Lin Huang
- College of Animal Sciences, Zhejiang University, Hangzhou 310058, P. R. China
| | - Weixia Zhang
- College of Animal Sciences, Zhejiang University, Hangzhou 310058, P. R. China
| | - Yu Han
- College of Animal Sciences, Zhejiang University, Hangzhou 310058, P. R. China
| | - Yu Tang
- College of Animal Sciences, Zhejiang University, Hangzhou 310058, P. R. China
| | - Weishang Zhou
- College of Animal Sciences, Zhejiang University, Hangzhou 310058, P. R. China
| | - Guangxu Liu
- College of Animal Sciences, Zhejiang University, Hangzhou 310058, P. R. China
| | - Wei Shi
- College of Animal Sciences, Zhejiang University, Hangzhou 310058, P. R. China
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11
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Zhou P, Liu P, Zhang Y, Wang D, Li A. The Response Dynamics and Function of Cholinergic and GABAergic Neurons in the Basal Forebrain During Olfactory Learning. Front Cell Neurosci 2022; 16:911439. [PMID: 35966196 PMCID: PMC9363711 DOI: 10.3389/fncel.2022.911439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Accepted: 06/23/2022] [Indexed: 11/13/2022] Open
Abstract
Modulation of neural circuits is essential for flexible sensory perception and decision-making in a changing environment. Cholinergic and GABAergic projections to the olfactory system from the horizontal limb of the diagonal band of Broca (HDB) in the basal forebrain are crucial for odor detection and olfactory learning. Although studies have demonstrated that HDB neurons respond during olfactory learning, how cholinergic and GABAergic neurons differ in their response dynamics and roles in olfactory learning remains unclear. In this study, we examined the response profiles of these two subpopulations of neurons during passive odor exposure and associative olfactory learning. We show that the excitatory responses in both cholinergic and GABAergic neurons tended to habituate during repeated passive odor exposure. However, while these habituated responses were also observed in GABAergic neurons during a go-go task, there was no such habituation in cholinergic neurons. Moreover, the responses to S+ and S− trials diverged in cholinergic neurons once mice learned a go/no-go task. Furthermore, the chemogenetic inactivation of cholinergic neurons in the HDB impaired odor discrimination. Together, these findings suggest that cholinergic neurons in the HDB reflect attention to positive reinforcement and may regulate odor discrimination via top–down inputs to the olfactory system.
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Affiliation(s)
| | | | | | | | - Anan Li
- *Correspondence: Dejuan Wang Anan Li
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12
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Urrutia-Piñones J, Morales-Moraga C, Sanguinetti-González N, Escobar AP, Chiu CQ. Long-Range GABAergic Projections of Cortical Origin in Brain Function. Front Syst Neurosci 2022; 16:841869. [PMID: 35392440 PMCID: PMC8981584 DOI: 10.3389/fnsys.2022.841869] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 02/10/2022] [Indexed: 12/12/2022] Open
Abstract
The study of long-range GABAergic projections has traditionally been focused on those with subcortical origin. In the last few years, cortical GABAergic neurons have been shown to not only mediate local inhibition, but also extend long-range axons to remote cortical and subcortical areas. In this review, we delineate the different types of long-range GABAergic neurons (LRGNs) that have been reported to arise from the hippocampus and neocortex, paying attention to the anatomical and functional circuits they form to understand their role in behavior. Although cortical LRGNs are similar to their interneuron and subcortical counterparts, they comprise distinct populations that show specific patterns of cortico-cortical and cortico-fugal connectivity. Functionally, cortical LRGNs likely induce timed disinhibition in target regions to synchronize network activity. Thus, LRGNs are emerging as a new element of cortical output, acting in concert with long-range excitatory projections to shape brain function in health and disease.
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Affiliation(s)
- Jocelyn Urrutia-Piñones
- Ph.D. Program in Neuroscience, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
- Facultad de Ciencias, Instituto de Neurociencia, Universidad de Valparaíso, Valparaíso, Chile
| | - Camila Morales-Moraga
- Facultad de Ciencias, Instituto de Neurociencia, Universidad de Valparaíso, Valparaíso, Chile
- Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
| | - Nicole Sanguinetti-González
- Ph.D. Program in Neuroscience, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
- Facultad de Ciencias, Instituto de Neurociencia, Universidad de Valparaíso, Valparaíso, Chile
| | - Angelica P. Escobar
- Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
- Centro de Neurobiología y Fisiopatología Integrativa, Universidad de Valparaíso, Valparaíso, Chile
| | - Chiayu Q. Chiu
- Facultad de Ciencias, Instituto de Neurociencia, Universidad de Valparaíso, Valparaíso, Chile
- Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
- *Correspondence: Chiayu Q. Chiu,
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13
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De Saint Jan D. Target-specific control of olfactory bulb periglomerular cells by GABAergic and cholinergic basal forebrain inputs. eLife 2022; 11:71965. [PMID: 35225232 PMCID: PMC8901171 DOI: 10.7554/elife.71965] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 02/16/2022] [Indexed: 11/13/2022] Open
Abstract
The olfactory bulb (OB), the first relay for odor processing in the brain, receives dense GABAergic and cholinergic long-range projections from basal forebrain (BF) nuclei that provide information about the internal state and behavioral context of the animal. However, the targets, impact, and dynamic of these afferents are still unclear. How BF synaptic inputs modulate activity in diverse subtypes of periglomerular (PG) interneurons using optogenetic stimulation and loose cell-attached or whole-cell patch-clamp recording in OB slices from adult mice were studied in this article. GABAergic BF inputs potently blocked PG cells firing except in a minority of calretinin-expressing cells in which GABA release elicited spiking. Parallel cholinergic projections excited a previously overlooked PG cell subtype via synaptic activation of M1 muscarinic receptors. Low-frequency stimulation of the cholinergic axons drove persistent firing in these PG cells, thereby increasing tonic inhibition in principal neurons. Taken together, these findings suggest that modality-specific BF inputs can orchestrate synaptic inhibition in OB glomeruli using multiple, potentially independent, inhibitory or excitatory target-specific pathways.
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Affiliation(s)
- Didier De Saint Jan
- Institut des Neurosciences Cellulaires et Intégratives, Centre National de la Recherche Scientifique, Strasbourg, France
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14
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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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15
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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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16
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Manzini I, Schild D, Di Natale C. Principles of odor coding in vertebrates and artificial chemosensory systems. Physiol Rev 2021; 102:61-154. [PMID: 34254835 DOI: 10.1152/physrev.00036.2020] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The biological olfactory system is the sensory system responsible for the detection of the chemical composition of the environment. Several attempts to mimic biological olfactory systems have led to various artificial olfactory systems using different technical approaches. Here we provide a parallel description of biological olfactory systems and their technical counterparts. We start with a presentation of the input to the systems, the stimuli, and treat the interface between the external world and the environment where receptor neurons or artificial chemosensors reside. We then delineate the functions of receptor neurons and chemosensors as well as their overall I-O relationships. Up to this point, our account of the systems goes along similar lines. The next processing steps differ considerably: while in biology the processing step following the receptor neurons is the "integration" and "processing" of receptor neuron outputs in the olfactory bulb, this step has various realizations in electronic noses. For a long period of time, the signal processing stages beyond the olfactory bulb, i.e., the higher olfactory centers were little studied. Only recently there has been a marked growth of studies tackling the information processing in these centers. In electronic noses, a third stage of processing has virtually never been considered. In this review, we provide an up-to-date overview of the current knowledge of both fields and, for the first time, attempt to tie them together. We hope it will be a breeding ground for better information, communication, and data exchange between very related but so far little connected fields.
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Affiliation(s)
- Ivan Manzini
- Animal Physiology and Molecular Biomedicine, Justus-Liebig-University Gießen, Gießen, Germany
| | - Detlev Schild
- Institute of Neurophysiology and Cellular Biophysics, University Medical Center, University of Göttingen, Göttingen, Germany
| | - Corrado Di Natale
- Department of Electronic Engineering, University of Rome Tor Vergata, Rome, Italy
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17
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Średniawa W, Wróbel J, Kublik E, Wójcik DK, Whittington MA, Hunt MJ. Network and synaptic mechanisms underlying high frequency oscillations in the rat and cat olfactory bulb under ketamine-xylazine anesthesia. Sci Rep 2021; 11:6390. [PMID: 33737621 PMCID: PMC7973548 DOI: 10.1038/s41598-021-85705-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 02/25/2021] [Indexed: 11/09/2022] Open
Abstract
Wake-related ketamine-dependent high frequency oscillations (HFO) can be recorded in local field potentials (LFP) from cortical and subcortical regions in rodents. The mechanisms underlying their generation and occurrence in higher mammals are unclear. Unfortunately, anesthetic doses of pure ketamine attenuate HFO, which has precluded their investigation under anesthesia. Here, we show ketamine-xylazine (KX) anesthesia is associated with a prominent 80–130 Hz rhythm in the olfactory bulb (OB) of rats, whereas 30–65 Hz gamma power is diminished. Simultaneous LFP and thermocouple recordings revealed the 80–130 Hz rhythm was dependent on nasal respiration. This rhythm persisted despite surgical excision of the piriform cortex. Silicon probes spanning the dorsoventral aspect of the OB revealed this rhythm was strongest in ventral areas and associated with microcurrent sources about the mitral layer. Pharmacological microinfusion studies revealed dependency on excitatory-inhibitory synaptic activity, but not gap junctions. Finally, a similar rhythm occurred in the OB of KX-anesthetized cats, which shared key features with our rodent studies. We conclude that the activity we report here is driven by nasal airflow, local excitatory-inhibitory interactions, and conserved in higher mammals. Additionally, KX anesthesia is a convenient model to investigate further the mechanisms underlying wake-related ketamine-dependent HFO.
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Affiliation(s)
- Władysław Średniawa
- Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Street, 02-093, Warsaw, Poland.,University of Warsaw, Faculty of Biology, Miecznikowa 1, 02-096, Warsaw, Poland
| | - Jacek Wróbel
- Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Street, 02-093, Warsaw, Poland
| | - Ewa Kublik
- Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Street, 02-093, Warsaw, Poland
| | - Daniel Krzysztof Wójcik
- Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Street, 02-093, Warsaw, Poland.,Faculty of Management and Social Communication, Jagiellonian University, 30-348, Cracow, Poland
| | | | - Mark Jeremy Hunt
- Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Street, 02-093, Warsaw, Poland. .,University of York, Heslington, NY, YO10 5DD, United Kingdom.
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18
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Zhou FW, Puche AC. Short-Term Plasticity in Cortical GABAergic Synapses on Olfactory Bulb Granule Cells Is Modulated by Endocannabinoids. Front Cell Neurosci 2021; 15:629052. [PMID: 33633545 PMCID: PMC7899975 DOI: 10.3389/fncel.2021.629052] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 01/14/2021] [Indexed: 01/20/2023] Open
Abstract
Olfactory bulb and higher processing areas are synaptically interconnected, providing rapid regulation of olfactory bulb circuit dynamics and sensory processing. Short-term plasticity changes at any of these synapses could modulate sensory processing and potentially short-term sensory memory. A key olfactory bulb circuit for mediating cortical feedback modulation is granule cells, which are targeted by multiple cortical regions including both glutamatergic excitatory inputs and GABAergic inhibitory inputs. There is robust endocannabinoid modulation of excitatory inputs to granule cells and here we explored whether there was also endocannabinoid modulation of the inhibitory cortical inputs to granule cells. We expressed light-gated cation channel channelrhodopsin-2 (ChR2) in GABAergic neurons in the horizontal limb of the diagonal band of Broca (HDB) and their projections to granule cells in olfactory bulb. Selective optical activation of ChR2 positive axons/terminals generated strong, frequency-dependent short-term depression of GABAA-mediated-IPSC in granule cells. As cannabinoid type 1 (CB1) receptor is heavily expressed in olfactory bulb granule cell layer (GCL) and there is endogenous endocannabinoid release in GCL, we investigated whether activation of CB1 receptor modulated the HDB IPSC and short-term depression at the HDB→granule cell synapse. Activation of the CB1 receptor by the exogenous agonist Win 55,212-2 significantly decreased the peak amplitude of individual IPSC and decreased short-term depression, while blockade of the CB1 receptor by AM 251 slightly increased individual IPSCs and increased short-term depression. Thus, we conclude that there is tonic endocannabinoid activation of the GABAergic projections of the HDB to granule cells, similar to the modulation observed with glutamatergic projections to granule cells. Modulation of inhibitory synaptic currents and frequency-dependent short-term depression could regulate the precise balance of cortical feedback excitation and inhibition of granule cells leading to changes in granule cell mediated inhibition of olfactory bulb output to higher processing areas.
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Affiliation(s)
- Fu-Wen Zhou
- Department of Anatomy and Neurobiology, Program in Neurosciences, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Adam C Puche
- Department of Anatomy and Neurobiology, Program in Neurosciences, University of Maryland School of Medicine, Baltimore, MD, United States
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19
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Hanson E, Brandel-Ankrapp KL, Arenkiel BR. Dynamic Cholinergic Tone in the Basal Forebrain Reflects Reward-Seeking and Reinforcement During Olfactory Behavior. Front Cell Neurosci 2021; 15:635837. [PMID: 33603646 PMCID: PMC7884767 DOI: 10.3389/fncel.2021.635837] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 01/11/2021] [Indexed: 11/13/2022] Open
Abstract
Sensory perception underlies how we internalize and interact with the external world. In order to adapt to changing circumstances and interpret signals in a variety of contexts, sensation needs to be reliable, but perception of sensory input needs to be flexible. An important mediator of this flexibility is top-down regulation from the cholinergic basal forebrain. Basal forebrain projection neurons serve as pacemakers and gatekeepers for downstream neural networks, modulating circuit activity across diverse neuronal populations. This top-down control is necessary for sensory cue detection, learning, and memory, and is disproportionately disrupted in neurodegenerative diseases associated with cognitive decline. Intriguingly, cholinergic signaling acts locally within the basal forebrain to sculpt the activity of basal forebrain output neurons. To determine how local cholinergic signaling impacts basal forebrain output pathways that participate in top-down regulation, we sought to define the dynamics of cholinergic signaling within the basal forebrain during motivated behavior and learning. Toward this, we utilized fiber photometry and the genetically encoded acetylcholine indicator GAChR2.0 to define temporal patterns of cholinergic signaling in the basal forebrain during olfactory-guided, motivated behaviors and learning. We show that cholinergic signaling reliably increased during reward seeking behaviors, but was strongly suppressed by reward delivery in a go/no-go olfactory-cued discrimination task. The observed transient reduction in cholinergic tone was mirrored by a suppression in basal forebrain GABAergic neuronal activity. Together, these findings suggest that cholinergic tone in the basal forebrain changes rapidly to reflect reward-seeking behavior and positive reinforcement and may impact downstream circuitry that modulates olfaction.
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Affiliation(s)
- Elizabeth Hanson
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States
| | - Katie L. Brandel-Ankrapp
- Postbaccalaureate Research Education 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
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20
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Martínez-García I, Hernández-Soto R, Villasana-Salazar B, Ordaz B, Peña-Ortega F. Alterations in Piriform and Bulbar Activity/Excitability/Coupling Upon Amyloid-β Administration in vivo Related to Olfactory Dysfunction. J Alzheimers Dis 2021; 82:S19-S35. [PMID: 33459655 DOI: 10.3233/jad-201392] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Deficits in odor detection and discrimination are premature symptoms of Alzheimer's disease (AD) that correlate with pathological signs in the olfactory bulb (OB) and piriform cortex (PCx). Similar olfactory dysfunction has been characterized in AD transgenic mice that overproduce amyloid-β peptide (Aβ), which can be prevented by reducing Aβ levels by immunological and pharmacological means, suggesting that olfactory dysfunction depends on Aβ accumulation and Aβ-driven alterations in the OB and/or PCx, as well as on their activation. However, this possibility needs further exploration. OBJECTIVE To characterize the effects of Aβ on OB and PCx excitability/coupling and on olfaction. METHODS Aβ oligomerized solution (containing oligomers, monomers, and protofibrils) or its vehicle were intracerebroventricularlly injected two weeks before OB and PCx excitability and synchrony were evaluated through field recordings in vivo and in brain slices. Synaptic transmission from the OB to the PCx was also evaluated in slices. Olfaction was assessed through the habituation/dishabituation test. RESULTS Aβ did not affect lateral olfactory tract transmission into the PCx but reduced odor habituation and cross-habituation. This olfactory dysfunction was related to a reduction of PCx and OB network activity power in vivo. Moreover, the coherence between PCx-OB activities was also reduced by Aβ. Finally, Aβ treatment exacerbated the 4-aminopyridine-induced excitation in the PCx in slices. CONCLUSION Our results show that Aβ-induced olfactory dysfunction involves a complex set of pathological changes at different levels of the olfactory pathway including alterations in PCx excitability and its coupling with the OB. These pathological changes might contribute to hyposmia in AD.
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Affiliation(s)
- Ignacio Martínez-García
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, UNAM-Campus Juriquilla, México
| | - Rebeca Hernández-Soto
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, UNAM-Campus Juriquilla, México
| | - Benjamín Villasana-Salazar
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, UNAM-Campus Juriquilla, México
| | - Benito Ordaz
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, UNAM-Campus Juriquilla, México
| | - Fernando Peña-Ortega
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, UNAM-Campus Juriquilla, México
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21
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Brunert D, Rothermel M. Extrinsic neuromodulation in the rodent olfactory bulb. Cell Tissue Res 2021; 383:507-524. [PMID: 33355709 PMCID: PMC7873007 DOI: 10.1007/s00441-020-03365-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 11/24/2020] [Indexed: 12/16/2022]
Abstract
Evolutionarily, olfaction is one of the oldest senses and pivotal for an individual's health and survival. The olfactory bulb (OB), as the first olfactory relay station in the brain, is known to heavily process sensory information. To adapt to an animal's needs, OB activity can be influenced by many factors either from within (intrinsic neuromodulation) or outside (extrinsic neuromodulation) the OB which include neurotransmitters, neuromodulators, hormones, and neuropeptides. Extrinsic sources seem to be of special importance as the OB receives massive efferent input from numerous brain centers even outweighing the sensory input from the nose. Here, we review neuromodulatory processes in the rodent OB from such extrinsic sources. We will discuss extrinsic neuromodulation according to points of origin, receptors involved, affected circuits, and changes in behavior. In the end, we give a brief outlook on potential future directions in research on neuromodulation in the OB.
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Affiliation(s)
- Daniela Brunert
- Department of Chemosensation, AG Neuromodulation, Institute for Biology II, RWTH Aachen University, 52074, Aachen, Germany
| | - Markus Rothermel
- Department of Chemosensation, AG Neuromodulation, Institute for Biology II, RWTH Aachen University, 52074, Aachen, Germany.
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22
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Losacco J, George NM, Hiratani N, Restrepo D. The Olfactory Bulb Facilitates Use of Category Bounds for Classification of Odorants in Different Intensity Groups. Front Cell Neurosci 2020; 14:613635. [PMID: 33362477 PMCID: PMC7759615 DOI: 10.3389/fncel.2020.613635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 11/16/2020] [Indexed: 11/22/2022] Open
Abstract
Signal processing of odor inputs to the olfactory bulb (OB) changes through top-down modulation whose shaping of neural rhythms in response to changes in stimulus intensity is not understood. Here we asked whether the representation of a high vs. low intensity odorant in the OB by oscillatory neural activity changed as the animal learned to discriminate odorant concentration ranges in a go-no go task. We trained mice to discriminate between high vs. low concentration odorants by learning to lick to the rewarded group (low or high). We recorded the local field potential (LFP) in the OB of these mice and calculated the theta-referenced beta or gamma oscillation power (theta phase-referenced power, or tPRP). We found that as the mouse learned to differentiate odorant concentrations, tPRP diverged between trials for the rewarded vs. the unrewarded concentration range. For the proficient animal, linear discriminant analysis was able to predict the rewarded odorant group and the performance of this classifier correlated with the percent correct behavior in the odor concentration discrimination task. Interestingly, the behavioral response and decoding accuracy were asymmetric as a function of concentration when the rewarded stimulus was shifted between the high and low odorant concentration ranges. A model for decision making motivated by the statistics of OB activity that uses a single threshold in a logarithmic concentration scale displays this asymmetry. Taken together with previous studies on the intensity criteria for decisions on odorant concentrations, our finding suggests that OB oscillatory events facilitate decision making to classify concentrations using a single intensity criterion.
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Affiliation(s)
- Justin Losacco
- Neuroscience Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Nicholas M. George
- Neuroscience Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Naoki Hiratani
- Gatsby Computational Neuroscience Unit, University College London, London, United Kingdom
| | - Diego Restrepo
- Neuroscience Graduate Program, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
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23
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Wang D, Chen Y, Chen Y, Li X, Liu P, Yin Z, Li A. Improved Separation of Odor Responses in Granule Cells of the Olfactory Bulb During Odor Discrimination Learning. Front Cell Neurosci 2020; 14:579349. [PMID: 33192325 PMCID: PMC7581703 DOI: 10.3389/fncel.2020.579349] [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: 07/02/2020] [Accepted: 09/14/2020] [Indexed: 01/01/2023] Open
Abstract
In the olfactory bulb, olfactory information is translated into ensemble representations by mitral/tufted cells, and these representations change dynamically in a context-dependent manner. In particular, odor representations in mitral/tufted cells display pattern separation during odor discrimination learning. Although granule cells provide major inhibitory input to mitral/tufted cells and play an important role in pattern separation and olfactory learning, the dynamics of odor responses in granule cells during odor discrimination learning remain largely unknown. Here, we studied odor responses in granule cells of the olfactory bulb using fiber photometry recordings in awake behaving mice. We found that odors evoked reliable, excitatory responses in the granule cell population. Intriguingly, during odor discrimination learning, odor responses in granule cells exhibited improved separation and contained information about odor value. In conclusion, we show that granule cells in the olfactory bulb display learning-related plasticity, suggesting that they may mediate pattern separation in mitral/tufted cells.
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Affiliation(s)
- Dejuan Wang
- Jiangsu Key Laboratory of Brain Disease and Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical University, Xuzhou, China
| | - Yang Chen
- Jiangsu Key Laboratory of Brain Disease and Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical University, Xuzhou, China
| | - Yiling Chen
- Jiangsu Key Laboratory of Brain Disease and Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical University, Xuzhou, China
| | - Xiaowen Li
- Jiangsu Key Laboratory of Brain Disease and Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical University, Xuzhou, China
| | - Penglai Liu
- Jiangsu Key Laboratory of Brain Disease and Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical University, Xuzhou, China
| | - Zhaoyang Yin
- Jiangsu Key Laboratory of Brain Disease and Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical University, Xuzhou, China
| | - Anan Li
- Jiangsu Key Laboratory of Brain Disease and Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical University, Xuzhou, China
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24
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Kouremenou I, Piper M, Zalucki O. Adult Neurogenesis in the Olfactory System: Improving Performance for Difficult Discrimination Tasks? Bioessays 2020; 42:e2000065. [PMID: 32767425 DOI: 10.1002/bies.202000065] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 07/17/2020] [Indexed: 02/04/2023]
Abstract
What is the function of new neurons entering the olfactory bulb? Many insights regarding the molecular control of adult neurogenesis have been uncovered, but the purpose of new neurons entering the olfactory bulb has been difficult to ascertain. Here, studies investigating the role of adult neurogenesis in olfactory discrimination in mice are reviewed. Studies in which adult neurogenesis is affected are highlighted, with a focus on the role of environment enrichment and what happens during ageing. There is evidence for a role of adult neurogenesis in fine discrimination tasks, as underscored by studies that enhance adult neurogenesis. This is also observed in ageing studies, where older mice with reduced levels of adult neurogenesis perform poorly in olfactory discrimination. Differences in methodology that could account for alternative conclusions, and the importance of specificity in methods being used to investigate the effect of adult neurogenesis in olfactory performance are emphasized.
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Affiliation(s)
- Ioanna Kouremenou
- The School of Biomedical Sciences, The University of Queensland, Brisbane, 4072, Australia
| | - Michael Piper
- The School of Biomedical Sciences, The University of Queensland, Brisbane, 4072, Australia.,Queensland Brain Institute, The University of Queensland, Brisbane, 4072, Australia
| | - Oressia Zalucki
- The School of Biomedical Sciences, The University of Queensland, Brisbane, 4072, Australia
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25
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Böhm E, Brunert D, Rothermel M. Input dependent modulation of olfactory bulb activity by HDB GABAergic projections. Sci Rep 2020; 10:10696. [PMID: 32612119 PMCID: PMC7329849 DOI: 10.1038/s41598-020-67276-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 05/27/2020] [Indexed: 12/16/2022] Open
Abstract
Basal forebrain modulation of central circuits is associated with active sensation, attention, and learning. While cholinergic modulations have been studied extensively the effect of non-cholinergic basal forebrain subpopulations on sensory processing remains largely unclear. Here, we directly compare optogenetic manipulation effects of two major basal forebrain subpopulations on principal neuron activity in an early sensory processing area, i.e. mitral/tufted cells (MTCs) in the olfactory bulb. In contrast to cholinergic projections, which consistently increased MTC firing, activation of GABAergic fibers from basal forebrain to the olfactory bulb leads to differential modulation effects: while spontaneous MTC activity is mainly inhibited, odor-evoked firing is predominantly enhanced. Moreover, sniff-triggered averages revealed an enhancement of maximal sniff evoked firing amplitude and an inhibition of firing rates outside the maximal sniff phase. These findings demonstrate that GABAergic neuromodulation affects MTC firing in a bimodal, sensory-input dependent way, suggesting that GABAergic basal forebrain modulation could be an important factor in attention mediated filtering of sensory information to the brain.
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Affiliation(s)
- Erik Böhm
- Department of Chemosensation, AG Neuromodulation, Institute for Biology II, RWTH Aachen University, Aachen, 52074, Germany
| | - Daniela Brunert
- Department of Chemosensation, AG Neuromodulation, Institute for Biology II, RWTH Aachen University, Aachen, 52074, Germany
| | - Markus Rothermel
- Department of Chemosensation, AG Neuromodulation, Institute for Biology II, RWTH Aachen University, Aachen, 52074, Germany.
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26
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Nunez-Parra A, Cea-Del Rio CA, Huntsman MM, Restrepo D. The Basal Forebrain Modulates Neuronal Response in an Active Olfactory Discrimination Task. Front Cell Neurosci 2020; 14:141. [PMID: 32581716 PMCID: PMC7289987 DOI: 10.3389/fncel.2020.00141] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 04/27/2020] [Indexed: 02/02/2023] Open
Abstract
Successful completion of sensory decision-making requires focusing on relevant stimuli, adequate signal/noise ratio for stimulus discrimination, and stimulus valence evaluation. Different brain regions are postulated to play a role in these computations; however, evidence suggests that sensory and decision-making circuits are required to interact through a common neuronal pathway to elicit a context-adequate behavioral response. Recently, the basal forebrain (BF) region has emerged as a good candidate, since its heterogeneous projecting neurons innervate most of the cortical mantle and sensory processing circuits modulating different aspects of the sensory decision-making process. Moreover, evidence indicates that the BF plays an important role in attention and in fast modulation of neuronal activity that enhance visual and olfactory sensory perception. Here, we study in awake mice the involvement of BF in initiation and completion of trials in a reward-driven olfactory detection task. Using tetrode recordings, we find that BF neurons (including cholinergics) are recruited during sensory discrimination, reward, and interestingly slightly before trial initiation in successful discrimination trials. The precue neuronal activity was correlated with animal performance, indicating that this circuit could play an important role in adaptive context-dependent behavioral responses.
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Affiliation(s)
- Alexia Nunez-Parra
- Department of Cell and Developmental Biology, Rocky Mountain Taste and Smell Center and Neuroscience Program, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
- Department of Biology, Faculty of Science, Universidad de Chile, Santiago, Chile
| | - Christian A. Cea-Del Rio
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
- Centro de Investigacion Biomedica y Aplicada (CIBAP), Escuela de Medicina, Facultad de Ciencias Medicas, Universidad de Santiago de Chile, Santiago, Chile
| | - Molly M. Huntsman
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
- Department of Pediatrics, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Diego Restrepo
- Department of Cell and Developmental Biology, Rocky Mountain Taste and Smell Center and Neuroscience Program, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
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27
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Hanson E, Swanson J, Arenkiel BR. GABAergic Input From the Basal Forebrain Promotes the Survival of Adult-Born Neurons in the Mouse Olfactory Bulb. Front Neural Circuits 2020; 14:17. [PMID: 32390805 PMCID: PMC7190813 DOI: 10.3389/fncir.2020.00017] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 03/31/2020] [Indexed: 12/15/2022] Open
Abstract
A unique feature of the olfactory system is the continuous generation and integration of new neurons throughout adulthood. Adult-born neuron survival and integration is dependent on activity and sensory experience, which is largely mediated by early synaptic inputs that adult-born neurons receive upon entering the olfactory bulb (OB). As in early postnatal development, the first synaptic inputs onto adult-born neurons are GABAergic. However, the specific sources of early synaptic GABA and the influence of specific inputs on adult-born neuron development are poorly understood. Here, we use retrograde and anterograde viral tracing to reveal robust GABAergic projections from the basal forebrain horizontal limb of the diagonal band of Broca (HDB) to the granule cell layer (GCL) and glomerular layer (GL) of the mouse OB. Whole-cell electrophysiological recordings indicate that these projections target interneurons in the GCL and GL, including adult-born granule cells (abGCs). Recordings from birth-dated abGCs reveal a developmental time course in which HDB GABAergic input onto abGCs emerges as the neurons first enter the OB, and strengthens throughout the critical period of abGC development. Finally, we show that removing GABAergic signaling from HDB neurons results in decreased abGC survival. Together these data show that GABAergic projections from the HDB synapse onto immature abGCs in the OB to promote their survival through the critical period, thus representing a source of long-range input modulating plasticity in the adult OB.
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Affiliation(s)
- Elizabeth Hanson
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States
| | - Jessica Swanson
- Department of Molecular and Human Genetics, 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
- Program in Developmental Biology, 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 at Texas Children’s Hospital, Baylor College of Medicine, Houston, TX, United States
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28
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Mitf Links Neuronal Activity and Long-Term Homeostatic Intrinsic Plasticity. eNeuro 2020; 7:ENEURO.0412-19.2020. [PMID: 32193365 PMCID: PMC7174873 DOI: 10.1523/eneuro.0412-19.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 02/07/2020] [Accepted: 03/02/2020] [Indexed: 12/25/2022] Open
Abstract
Neuroplasticity forms the basis for neuronal circuit complexity and differences between otherwise similar circuits. We show that the microphthalmia-associated transcription factor (Mitf) plays a central role in intrinsic plasticity of olfactory bulb (OB) projection neurons. Mitral and tufted (M/T) neurons from Mitf mutant mice are hyperexcitable, have a reduced A-type potassium current (IA) and exhibit reduced expression of Kcnd3, which encodes a potassium voltage-gated channel subunit (Kv4.3) important for generating the IA Furthermore, expression of the Mitf and Kcnd3 genes is activity dependent in OB projection neurons and the MITF protein activates expression from Kcnd3 regulatory elements. Moreover, Mitf mutant mice have changes in olfactory habituation and have increased habituation for an odorant following long-term exposure, indicating that regulation of Kcnd3 is pivotal for long-term olfactory adaptation. Our findings show that Mitf acts as a direct regulator of intrinsic homeostatic feedback and links neuronal activity, transcriptional changes and neuronal function.
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29
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Lane G, Zhou G, Noto T, Zelano C. Assessment of direct knowledge of the human olfactory system. Exp Neurol 2020; 329:113304. [PMID: 32278646 DOI: 10.1016/j.expneurol.2020.113304] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 01/13/2020] [Accepted: 04/08/2020] [Indexed: 12/31/2022]
Affiliation(s)
- Gregory Lane
- Northwestern University Feinberg School of Medicine, Department of Neurology, 303 E Chicago Ave, Chicago, IL 60611, USA.
| | - Guangyu Zhou
- Northwestern University Feinberg School of Medicine, Department of Neurology, 303 E Chicago Ave, Chicago, IL 60611, USA.
| | - Torben Noto
- Northwestern University Feinberg School of Medicine, Department of Neurology, 303 E Chicago Ave, Chicago, IL 60611, USA
| | - Christina Zelano
- Northwestern University Feinberg School of Medicine, Department of Neurology, 303 E Chicago Ave, Chicago, IL 60611, USA
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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: 17] [Impact Index Per Article: 4.3] [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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Sudden Intrabulbar Amyloid Increase Simultaneously Disrupts Olfactory Bulb Oscillations and Odor Detection. Neural Plast 2019; 2019:3424906. [PMID: 31531013 PMCID: PMC6721117 DOI: 10.1155/2019/3424906] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 06/11/2019] [Accepted: 06/24/2019] [Indexed: 02/07/2023] Open
Abstract
There seems to be a correlation between soluble amyloid beta protein (Aβ) accumulation in the main olfactory bulb (OB) and smell deterioration in both Alzheimer's disease (AD) patients and animal models. Moreover, this loss of smell appears to be related to alterations in neural network activity in several olfactory-related circuits, including the OB, as has been observed in anesthetized animals and brain slices. It is possible that there is a correlation between these two pathological phenomena, but a direct and simultaneous evaluation of the acute and direct effect of Aβ on OB activity while animals are actually smelling has not been performed. Thus, here, we tested the effects of acute intrabulbar injection of Aβ at a low dose (200 pmol) on the OB local field potential before and during the presence of a hidden piece of smelly food. Our results show that Aβ decreases the power of OB network activity while impairing the animal's ability to reach the hidden food. We found a strong relationship between the power of the OB oscillations and the correlation between OBs and the olfactory detection test scores. These findings provide a direct link between Aβ-induced OB network dysfunction and smell loss in rodents, which could be extrapolated to AD patients.
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32
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Notsu E, Toida K. Examination of morphological and synaptic features of calbindin-immunoreactive neurons in deep layers of the rat olfactory bulb with correlative laser and volume electron microscopy. Microscopy (Oxf) 2019; 68:316-329. [PMID: 31062844 DOI: 10.1093/jmicro/dfz019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 03/21/2019] [Accepted: 04/09/2019] [Indexed: 06/09/2023] Open
Abstract
The olfactory bulb (OB) contains various interneuron types that play key roles in processing olfactory information via synaptic contacts. Many previous studies have reported synaptic connections of heterogeneous interneurons in superficial OB layers. In contrast, few studies have examined synaptic connections in deep layers because of the lack of a selective marker for intrinsic neurons located in the deeper layers, including the mitral cell layer, internal plexiform layer (IPL) and granule cell layer. However, neural circuits in the deep layers are likely to have a strong effect on the output of the OB because of the cellular composition of these regions. Here, we analyzed the calbindin-immunoreactive neurons in the IPL, one of the clearly neurochemically defined interneuron types in the deep layers, using multiple immunolabeling and confocal laser scanning microscopy combined with electron microscopic three-dimensional serial-section reconstruction, enabling correlated laser and volume electron microscopy (EM). Despite a resemblance to the morphological features of deep short axon cells, IPL calbindin-immunoreactive (IPL-CB-ir) neurons lacked axons. Furthermore, multiple immunolabeling for plural neurochemicals indicated that IPL-CB-ir neurons differed from any interneuron types reported previously. We identified symmetrical synapses formed by IPL-CB-ir neurons on granule cells (GCs) using correlated laser and volume EM. These synapses might inhibit GCs and thus disinhibit mitral and tufted cells. Our present findings indicate, for the first time, that IPL-CB-ir neurons are involved in regulating the activities of projection neurons, further suggesting their involvement in synaptic circuitry for output from the deeper layers of the OB, which has not previously been clarified.
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Affiliation(s)
- Eiji Notsu
- Department of Anatomy, Kawasaki Medical School, Kurashiki, Okayama 701-0192, Japan
| | - Kazunori Toida
- Department of Anatomy, Kawasaki Medical School, Kurashiki, Okayama 701-0192, Japan
- Research Center for Ultra-High Voltage Electron Microscopy, Osaka University, Ibaraki, Osaka 567-0047, Japan
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33
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Zhang X, Coates K, Dacks A, Günay C, Lauritzen JS, Li F, Calle-Schuler SA, Bock D, Gaudry Q. Local synaptic inputs support opposing, network-specific odor representations in a widely projecting modulatory neuron. eLife 2019; 8:46839. [PMID: 31264962 PMCID: PMC6660217 DOI: 10.7554/elife.46839] [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: 03/14/2019] [Accepted: 07/01/2019] [Indexed: 12/14/2022] Open
Abstract
Serotonin plays different roles across networks within the same sensory modality. Previously, we used whole-cell electrophysiology in Drosophila to show that serotonergic neurons innervating the first olfactory relay are inhibited by odorants (Zhang and Gaudry, 2016). Here we show that network-spanning serotonergic neurons segregate information about stimulus features, odor intensity and identity, by using opposing coding schemes in different olfactory neuropil. A pair of serotonergic neurons (the CSDns) innervate the antennal lobe and lateral horn, which are first and second order neuropils. CSDn processes in the antennal lobe are inhibited by odors in an identity independent manner. In the lateral horn, CSDn processes are excited in an odor identity dependent manner. Using functional imaging, modeling, and EM reconstruction, we demonstrate that antennal lobe derived inhibition arises from local GABAergic inputs and acts as a means of gain control on branch-specific inputs that the CSDns receive within the lateral horn.
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Affiliation(s)
- Xiaonan Zhang
- Department of Biology, University of Maryland, College Park, United States
| | - Kaylynn Coates
- Department of Biology, West Virginia University, Morgantown, United States
| | - Andrew Dacks
- Department of Biology, West Virginia University, Morgantown, United States
| | - Cengiz Günay
- School of Science and Technology, Georgia Gwinnett College, Lawrenceville, United States
| | - J Scott Lauritzen
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Feng Li
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | | | - Davi Bock
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, United States.,Department of Neurological Sciences, Larner College of Medicine, University of Vermont, Burlington, United States
| | - Quentin Gaudry
- Department of Biology, University of Maryland, College Park, United States
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34
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Wen P, Rao X, Xu L, Zhang Z, Jia F, He X, Xu F. Cortical Organization of Centrifugal Afferents to the Olfactory Bulb: Mono- and Trans-synaptic Tracing with Recombinant Neurotropic Viral Tracers. Neurosci Bull 2019; 35:709-723. [PMID: 31069620 DOI: 10.1007/s12264-019-00385-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 09/14/2018] [Indexed: 01/14/2023] Open
Abstract
Sensory processing is strongly modulated by different brain and behavioral states, and this is based on the top-down modulation. In the olfactory system, local neural circuits in the olfactory bulb (OB) are innervated by centrifugal afferents in order to regulate the processing of olfactory information in the OB under different behavioral states. The purpose of the present study was to explore the organization of neural networks in olfactory-related cortices and modulatory nuclei that give rise to direct and indirect innervations to the glomerular layer (GL) of the OB at the whole-brain scale. Injection of different recombinant attenuated neurotropic viruses into the GL showed that it received direct inputs from each layer in the OB, centrifugal inputs from the ipsilateralanterior olfactory nucleus (AON), anterior piriform cortex (Pir), and horizontal limb of diagonal band of Broca (HDB), and various indirect inputs from bilateral cortical neurons in the AON, Pir, amygdala, entorhinal cortex, hippocampus, HDB, dorsal raphe, median raphe and locus coeruleus. These results provide a circuitry basis that will help further understand the mechanism by which olfactory information-processing in the OB is regulated.
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Affiliation(s)
- Pengjie Wen
- Center of Brain Science, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Institute of Physics and Mathematics, Center for Excellence in Brain Science and Intelligent Technology, Chinese Academy of Sciences, Wuhan, 430071, China
- University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiaoping Rao
- Center of Brain Science, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Institute of Physics and Mathematics, Center for Excellence in Brain Science and Intelligent Technology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Liuying Xu
- College of Life Science, Wuhan University, Wuhan, 430072, China
| | - Zhijian Zhang
- Center of Brain Science, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Institute of Physics and Mathematics, Center for Excellence in Brain Science and Intelligent Technology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Fan Jia
- Center of Brain Science, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Institute of Physics and Mathematics, Center for Excellence in Brain Science and Intelligent Technology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Xiaobin He
- Center of Brain Science, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Institute of Physics and Mathematics, Center for Excellence in Brain Science and Intelligent Technology, Chinese Academy of Sciences, Wuhan, 430071, China.
| | - Fuqiang Xu
- Center of Brain Science, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Institute of Physics and Mathematics, Center for Excellence in Brain Science and Intelligent Technology, Chinese Academy of Sciences, Wuhan, 430071, China.
- Divisions of Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Wuhan, 430074, China.
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35
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Nocera S, Simon A, Fiquet O, Chen Y, Gascuel J, Datiche F, Schneider N, Epelbaum J, Viollet C. Somatostatin Serves a Modulatory Role in the Mouse Olfactory Bulb: Neuroanatomical and Behavioral Evidence. Front Behav Neurosci 2019; 13:61. [PMID: 31024270 PMCID: PMC6465642 DOI: 10.3389/fnbeh.2019.00061] [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: 10/03/2018] [Accepted: 03/12/2019] [Indexed: 11/30/2022] Open
Abstract
Somatostatin (SOM) and somatostatin receptors (SSTR1-4) are present in all olfactory structures, including the olfactory bulb (OB), where SOM modulates physiological gamma rhythms and olfactory discrimination responses. In this work, histological, viral tracing and transgenic approaches were used to characterize SOM cellular targets in the murine OB. We demonstrate that SOM targets all levels of mitral dendritic processes in the OB with somatostatin receptor 2 (SSTR2) detected in the dendrites of previously uncharacterized mitral-like cells. We show that inhibitory interneurons of the glomerular layer (GL) express SSTR4 while SSTR3 is confined to the granule cell layer (GCL). Furthermore, SOM cells in the OB receive synaptic inputs from olfactory cortical afferents. Behavioral studies demonstrate that genetic deletion of SSTR4, SSTR2 or SOM differentially affects olfactory performance. SOM or SSTR4 deletion have no major effect on olfactory behavioral performances while SSTR2 deletion impacts olfactory detection and discrimination behaviors. Altogether, these results describe novel anatomical and behavioral contributions of SOM, SSTR2 and SSTR4 receptors in olfactory processing.
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Affiliation(s)
- Sonia Nocera
- INSERM, UMR 894-Center for Psychiatry and Neuroscience (CPN), Paris, France
- Université Paris Descartes-Sorbonne Paris Cité, Paris, France
| | - Axelle Simon
- INSERM, UMR 894-Center for Psychiatry and Neuroscience (CPN), Paris, France
- Université Paris Descartes-Sorbonne Paris Cité, Paris, France
| | - Oriane Fiquet
- INSERM, UMR 894-Center for Psychiatry and Neuroscience (CPN), Paris, France
- Université Paris Descartes-Sorbonne Paris Cité, Paris, France
| | - Ying Chen
- INSERM, UMR 894-Center for Psychiatry and Neuroscience (CPN), Paris, France
- Université Paris Descartes-Sorbonne Paris Cité, Paris, France
| | - Jean Gascuel
- CNRS UMR 6265—Centre des Sciences du Goût et de l’Alimentation (CSGA), Dijon, France
| | - Frédérique Datiche
- CNRS UMR 6265—Centre des Sciences du Goût et de l’Alimentation (CSGA), Dijon, France
| | - Nanette Schneider
- CNRS UMR 6265—Centre des Sciences du Goût et de l’Alimentation (CSGA), Dijon, France
| | - Jacques Epelbaum
- INSERM, UMR 894-Center for Psychiatry and Neuroscience (CPN), Paris, France
- Université Paris Descartes-Sorbonne Paris Cité, Paris, France
| | - Cécile Viollet
- INSERM, UMR 894-Center for Psychiatry and Neuroscience (CPN), Paris, France
- Université Paris Descartes-Sorbonne Paris Cité, Paris, France
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36
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Sanz Diez A, Najac M, De Saint Jan D. Basal forebrain GABAergic innervation of olfactory bulb periglomerular interneurons. J Physiol 2019; 597:2547-2563. [PMID: 30920662 DOI: 10.1113/jp277811] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Accepted: 03/22/2019] [Indexed: 12/30/2022] Open
Abstract
KEY POINTS Basal forebrain long-range projections to the olfactory bulb are important for olfactory sensitivity and odour discrimination. Using optogenetics, it was confirmed that basal forebrain afferents mediate IPSCs on granule and deep short axon cells. It was also shown that they selectively innervate specific subtypes of periglomerular (PG) cells. Three different subtypes of type 2 PG cells receive GABAergic IPSCs from the basal forebrain but not from other PG cells. Type 1 PG cells, in contrast, do not receive inputs from the basal forebrain but do receive inhibition from other PG cells. These results shed new light on the complexity and specificity of glomerular inhibitory circuits, as well as on their modulation by the basal forebrain. ABSTRACT Olfactory bulb circuits are dominated by multiple inhibitory pathways that finely tune the activity of mitral and tufted cells, the principal neurons, and regulate odour discrimination. Granule cells mediate interglomerular lateral inhibition between mitral and tufted cells' lateral dendrites whereas diverse subtypes of periglomerular (PG) cells mediate intraglomerular lateral inhibition between their apical dendrites. Deep short axon cells form broad intrabulbar inhibitory circuits that regulate both populations of interneurons. Little is known about the extrabulbar GABAergic circuits that control the activity of these various interneurons. We examined this question using patch-clamp recordings and optogenetics in olfactory bulb slices from transgenic mice. We showed that axonal projections emanating from diverse basal forebrain GABAergic neurons densely project in all layers of the olfactory bulb. These long-range GABAergic projections provide a prominent synaptic input on granule and short axon cells in deep layers as well as on selective subtypes of PG cells. Specifically, three different subclasses of type 2 PG cells receive robust and target-specific basal forebrain inputs but have little local interactions with other PG cells. In contrast, type 1 PG cells are not innervated by basal forebrain fibres but do interact with other PG cells. Thus, attention-regulated basal forebrain inputs regulate inhibition in all layers of the olfactory bulb with a previously overlooked synaptic complexity that further defines interneuron subclasses.
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Affiliation(s)
- Alvaro Sanz Diez
- Institut des Neurosciences Cellulaires et Intégratives, Centre National de la Recherche Scientifique, Unité Propre de Recherche 3212, Université de Strasbourg, 67084, Strasbourg, France
| | - Marion Najac
- Department of Neurobiology, Northwestern University, Evanston, IL, 60208, USA
| | - Didier De Saint Jan
- Institut des Neurosciences Cellulaires et Intégratives, Centre National de la Recherche Scientifique, Unité Propre de Recherche 3212, Université de Strasbourg, 67084, Strasbourg, France
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37
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Tseng CS, Chou SJ, Huang YS. CPEB4-Dependent Neonate-Born Granule Cells Are Required for Olfactory Discrimination. Front Behav Neurosci 2019; 13:5. [PMID: 30728769 PMCID: PMC6351472 DOI: 10.3389/fnbeh.2019.00005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 01/08/2019] [Indexed: 11/23/2022] Open
Abstract
The rodent olfactory bulb (OB) contains two distinct populations of postnatally born interneurons, mainly granule cells (GCs), to support local circuits throughout life. During the early postnatal period (i.e., 2 weeks after birth), GCs are mostly produced locally from progenitor cells in the OB with a proportion of them deriving from proliferating cells in the rostral migratory stream (RMS). Afterward, the replenishment of GCs involves differentiated neuroblasts from the subventricular zone (SVZ) in a process known as adult neurogenesis. Although numerous studies have addressed the role of SVZ-born GCs in olfactory behaviors, the function of GCs produced early postnatally in the OB remains elusive. Our previous study demonstrated that the translational regulator, cytoplasmic polyadenylation element-binding protein 4 (CPEB4), is a survival factor exclusively for neonate-born but not SVZ/adult-derived GCs, so CPEB4-knockout (KO) mice provide unique leverage to study early postnatal-born GC-regulated olfactory functions. CPEB4-KO mice with hypoplastic OBs showed normal olfactory sensitivity and short-term memory, but impaired ability to spontaneously discriminate two odors. Such olfactory dysfunction was recapitulated in specific ablation of Cpeb4 gene in inhibitory interneurons but not in excitatory projection neurons or SVZ-derived interneurons. The continuous supply of GCs from adult neurogenesis eventually restored the OB size but not the discrimination function in 6-month-old KO mice. Hence, in the early postnatal OB, whose function cannot be replaced by adult-born GCs, construct critical circuits for odor discrimination.
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Affiliation(s)
- Ching-San Tseng
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Shen-Ju Chou
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan
| | - Yi-Shuian Huang
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
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Zhou FW, Puche AC, Shipley MT. Short-Term Plasticity at Olfactory Cortex to Granule Cell Synapses Requires Ca V2.1 Activation. Front Cell Neurosci 2018; 12:387. [PMID: 30416429 PMCID: PMC6212651 DOI: 10.3389/fncel.2018.00387] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 10/09/2018] [Indexed: 11/30/2022] Open
Abstract
Output projections of the olfactory bulb (OB) to the olfactory cortex (OCX) and reciprocal feedback projections from OCX provide rapid regulation of OB circuit dynamics and odor processing. Short-term synaptic plasticity (STP), a feature of many synaptic connections in the brain, can modulate the strength of feedback based on preceding network activity. We used light-gated cation channel channelrhodopsin-2 (ChR2) to investigate plasticity of excitatory synaptic currents (EPSCs) evoked at the OCX to granule cell (GC) synapse in the OB. Selective activation of OCX glutamatergic axons/terminals in OB generates strong, frequency-dependent STP in GCs. This plasticity was critically dependent on activation of CaV2.1 channels. As acetylcholine (ACh) modulates CaV2.1 channels in other brain regions and as cholinergic projections from the basal forebrain heavily target the GC layer (GCL) in OB, we investigated whether ACh modulates STP at the OCX→GC synapse. ACh decreases OCX→GC evoked EPSCs, it had no effect on STP. Thus, ACh impact on cortical feedback is independent of CaV2.1-mediated STP. Modulation of OCX feedback to the bulb by modulatory transmitters, such as ACh, or by frequency-dependent STP could regulate the precise balance of excitation and inhibition of GCs. As GCs are a major inhibitory source for OB output neurons, plasticity at the cortical feedback synapse can differentially impact OB output to higher-order networks in situations where ACh inputs are activated or by active sniff sampling of odors.
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Affiliation(s)
- Fu-Wen Zhou
- Department of Anatomy and Neurobiology, Program in Neurosciences, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Adam C Puche
- Department of Anatomy and Neurobiology, Program in Neurosciences, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Michael T Shipley
- Department of Anatomy and Neurobiology, Program in Neurosciences, University of Maryland School of Medicine, Baltimore, MD, United States
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Shang M, Xing J. Blocking of Dendrodendritic Inhibition Unleashes Widely Spread Lateral Propagation of Odor-evoked Activity in the Mouse Olfactory Bulb. Neuroscience 2018; 391:50-59. [PMID: 30208337 DOI: 10.1016/j.neuroscience.2018.09.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 09/01/2018] [Accepted: 09/03/2018] [Indexed: 01/27/2023]
Abstract
The olfactory circuitry in mice involves a well-characterized, vertical receptor type-specific organization, but the localized inhibitory effect from granule cells on action potentials that propagate laterally in secondary dendrites of mitral cell remains open to debate. To understand the functional dynamics of the lateral (horizontal) circuits, we analyzed odor-induced signaling using transgenic mice expressing a genetically encoded Ca2+ indicator specifically in mitral/tufted and some juxtaglomerular cells. Optical imaging of the dorsal olfactory bulb (dOB) revealed specific patterns of glomerular activation in response to odor presentation or direct electric stimulation of the olfactory nerve (ON). Application of a mixture of ionotropic and metabotropic glutamate receptor antagonists onto the exposed dOB completely abolished the responses to direct stimulation of the ON as well as discrete odor-evoked glomerular responses patterns, while a spatially more widespread response component increased and expanded into previously nonresponsive regions. To test whether the widespread odor response component represented signal propagation along mitral cell secondary dendrites, an NMDA receptor antagonist alone was applied to the dOB and was found to also increase and expand odor-evoked response patterns. Finally, with dOB excitatory synaptic transmission completely blocked, application of 1 mM muscimol (a GABAA receptor agonist) to a circumscribed volume in the deep external plexiform layer (EPL) induced an odor non-responsive area. These results indicate that odor stimulation can activate olfactory reciprocal synapses and control lateral interactions among olfactory glomerular modules along a wide range of mitral cell secondary dendrites by modulating the inhibitory effect from granule cells.
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Affiliation(s)
- Mengjuan Shang
- Department of Radiation Medicine, Faculty of Preventive Medicine, Airforce Medical University, 169(#) ChangLe West Road, Xi'an 710032, China
| | - Junling Xing
- Department of Radiation Biology, Faculty of Preventive Medicine, Airforce Medical University, 169(#) ChangLe West Road, Xi'an 710032, China; Department of Neurobiology, Yale University School of Medicine, New Haven, CT 06520-8001, USA.
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Takahashi H, Yoshihara S, Tsuboi A. The Functional Role of Olfactory Bulb Granule Cell Subtypes Derived From Embryonic and Postnatal Neurogenesis. Front Mol Neurosci 2018; 11:229. [PMID: 30034321 PMCID: PMC6043811 DOI: 10.3389/fnmol.2018.00229] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 06/12/2018] [Indexed: 02/01/2023] Open
Abstract
It has been shown in a variety of mammalian species that sensory experience can regulate the development of various structures, including the retina, cortex, hippocampus, and olfactory bulb (OB). In the mammalian OB, the development of dendrites in excitatory projection neurons, such as mitral and tufted cells, is well known to be dependent on odor experience. Odor experience is also involved in the development of another OB population, a subset of inhibitory interneurons that are generated in the ventricular-subventricular zone throughout life and differentiate into granule cells (GCs) and periglomerular cells. However, the roles that each type of interneuron plays in the control of olfactory behaviors are incompletely understood. We recently found that among the various types of OB interneurons, a subtype of GCs expressing the oncofetal trophoblast glycoprotein 5T4 gene is required for odor detection and discrimination behaviors. Our results suggest that embryonic-born OB interneurons, including 5T4-positive GCs, play a crucial role in fundamental olfactory responses such as simple odor detection and discrimination behaviors. By contrast, postnatal- and adult-born OB interneurons are important in the learning of more complicated olfactory behaviors. Here, we highlight the subtypes of OB GCs, and discuss their roles in olfactory processing and behavior, with a particular focus on the relative contributions of embryonically and postnatally generated subsets of GCs in rodents.
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Affiliation(s)
- Hiroo Takahashi
- Laboratory for the Molecular Biology of Neural Systems, Advanced Medical Research Center, Nara Medical University, Kashihara, Japan
| | - Seiichi Yoshihara
- Laboratory for the Molecular Biology of Neural Systems, Advanced Medical Research Center, Nara Medical University, Kashihara, Japan
| | - Akio Tsuboi
- Laboratory for the Molecular Biology of Neural Systems, Advanced Medical Research Center, Nara Medical University, Kashihara, Japan.,Laboratory for the Molecular and Cellular Neuroscience, Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
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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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Lack of Pattern Separation in Sensory Inputs to the Olfactory Bulb during Perceptual Learning. eNeuro 2017; 4:eN-NWR-0287-17. [PMID: 28955724 PMCID: PMC5615249 DOI: 10.1523/eneuro.0287-17.2017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 09/04/2017] [Accepted: 09/11/2017] [Indexed: 11/21/2022] Open
Abstract
Recent studies revealed changes in odor representations in the olfactory bulb during active olfactory learning (Chu et al., 2016; Yamada et al., 2017). Specifically, mitral cell ensemble responses to very similar odorant mixtures sparsened and became more distinguishable as mice learned to discriminate the odorants over days (Chu et al., 2016). In this study, we explored whether changes in the sensory inputs to the bulb underlie the observed changes in mitral cell responses. Using two-photon calcium imaging to monitor the odor responses of the olfactory sensory neuron (OSN) axon terminals in the glomeruli of the olfactory bulb during a discrimination task, we found that OSN inputs to the bulb are stable during discrimination learning. During one week of training to discriminate between very similar odorant mixtures in a Go/No-go task, OSN responses did not show significant sparsening, and the responses to the trained similar odorants did not diverge throughout training. These results suggest that the adaptive changes of mitral cell responses during perceptual learning are ensured by mechanisms downstream of OSN input, possibly in local circuits within olfactory bulb.
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Wang S, Hu T, Wang Z, Li N, Zhou L, Liao L, Wang M, Liao L, Wang H, Zeng L, Fan C, Zhou H, Xiong K, Huang J, Chen D. Macroglia-derived thrombospondin 2 regulates alterations of presynaptic proteins of retinal neurons following elevated hydrostatic pressure. PLoS One 2017; 12:e0185388. [PMID: 28953973 PMCID: PMC5617560 DOI: 10.1371/journal.pone.0185388] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 09/12/2017] [Indexed: 02/03/2023] Open
Abstract
Many studies on retinal injury and repair following elevated intraocular pressure suggest that the survival ratio of retinal neurons has been improved by various measures. However, the visual function recovery is far lower than expected. The homeostasis of retinal synapses in the visual signal pathway is the key structural basis for the delivery of visual signals. Our previous studies found that complicated changes in the synaptic structure between retinal neurons occurred much earlier than obvious degeneration of retinal ganglion cells in rat retinae. The lack of consideration of these earlier retinal synaptic changes in the rescue strategy may be partly responsible for the limited visual function recovery with the types of protective methods for retinal neurons used following elevated intraocular pressure. Thus, research on the modulatory mechanisms of the synaptic changes after elevated intraocular pressure injury may give new light to visual function rescue. In this study, we found that thrombospondin 2, an important regulator of synaptogenesis in central nervous system development, was distributed in retinal macroglia cells, and its receptor α2δ-1 was in retinal neurons. Cell cultures including mixed retinal macroglia cells/neuron cultures and retinal neuron cultures were exposed to elevated hydrostatic pressure for 2 h. The expression levels of glial fibrillary acidic protein (the marker of activated macroglia cells), thrombospondin 2, α2δ-1 and presynaptic proteins were increased following elevated hydrostatic pressure in mixed cultures, but the expression levels of postsynaptic proteins were not changed. SiRNA targeting thrombospondin 2 could decrease the upregulation of presynaptic proteins induced by the elevated hydrostatic pressure. However, in retinal neuron cultures, elevated hydrostatic pressure did not affect the expression of presynaptic or postsynaptic proteins. Rather, the retinal neuron cultures with added recombinant thrombospondin 2 protein upregulated the level of presynaptic proteins. Finally, gabapentin decreased the expression of presynaptic proteins in mixed cultures by blocking the interaction of thrombospondin 2 and α2δ-1. Taken together, these results indicate that activated macroglia cells may participate in alterations of presynaptic proteins of retinal neurons following elevated hydrostatic pressure, and macroglia-derived thrombospondin 2 may modulate these changes via binding to its neuronal receptor α2δ-1.
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Affiliation(s)
- Shuchao Wang
- Department of Anatomy and Neurobiology, Central South University School of Basic Medical Sciences, Changsha, Hunan, China
| | - Tu Hu
- Department of Anatomy and Neurobiology, Central South University School of Basic Medical Sciences, Changsha, Hunan, China
| | - Zhen Wang
- Department of Anatomy and Neurobiology, Central South University School of Basic Medical Sciences, Changsha, Hunan, China
| | - Na Li
- Department of Anatomy and Neurobiology, Central South University School of Basic Medical Sciences, Changsha, Hunan, China
| | - Lihong Zhou
- Department of Anatomy and Neurobiology, Central South University School of Basic Medical Sciences, Changsha, Hunan, China
| | - Lvshuang Liao
- Department of Anatomy and Neurobiology, Central South University School of Basic Medical Sciences, Changsha, Hunan, China
| | - Mi Wang
- Department of Anatomy and Neurobiology, Central South University School of Basic Medical Sciences, Changsha, Hunan, China
| | - Libin Liao
- Department of Anatomy and Neurobiology, Central South University School of Basic Medical Sciences, Changsha, Hunan, China
| | - Hui Wang
- Department of Anatomy and Neurobiology, Central South University School of Basic Medical Sciences, Changsha, Hunan, China
| | - Leping Zeng
- Department of Anatomy and Neurobiology, Central South University School of Basic Medical Sciences, Changsha, Hunan, China
| | - Chunling Fan
- Department of Anatomy and Neurobiology, Central South University School of Basic Medical Sciences, Changsha, Hunan, China
| | - Hongkang Zhou
- Department of Anatomy and Neurobiology, Central South University School of Basic Medical Sciences, Changsha, Hunan, China
| | - Kun Xiong
- Department of Anatomy and Neurobiology, Central South University School of Basic Medical Sciences, Changsha, Hunan, China
| | - Jufang Huang
- Department of Anatomy and Neurobiology, Central South University School of Basic Medical Sciences, Changsha, Hunan, China
- * E-mail: (JH); (DC)
| | - Dan Chen
- Department of Anatomy and Neurobiology, Central South University School of Basic Medical Sciences, Changsha, Hunan, China
- * E-mail: (JH); (DC)
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Burton SD. Inhibitory circuits of the mammalian main olfactory bulb. J Neurophysiol 2017; 118:2034-2051. [PMID: 28724776 DOI: 10.1152/jn.00109.2017] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 07/14/2017] [Accepted: 07/14/2017] [Indexed: 01/15/2023] Open
Abstract
Synaptic inhibition critically influences sensory processing throughout the mammalian brain, including the main olfactory bulb (MOB), the first station of sensory processing in the olfactory system. Decades of research across numerous laboratories have established a central role for granule cells (GCs), the most abundant GABAergic interneuron type in the MOB, in the precise regulation of principal mitral and tufted cell (M/TC) firing rates and synchrony through lateral and recurrent inhibitory mechanisms. In addition to GCs, however, the MOB contains a vast diversity of other GABAergic interneuron types, and recent findings suggest that, while fewer in number, these oft-ignored interneurons are just as important as GCs in shaping odor-evoked M/TC activity. Here I challenge the prevailing centrality of GCs. In this review, I first outline the specific properties of each GABAergic interneuron type in the rodent MOB, with particular emphasis placed on direct interneuron recordings and cell type-selective manipulations. On the basis of these properties, I then critically reevaluate the contribution of GCs vs. other interneuron types to the regulation of odor-evoked M/TC firing rates and synchrony via lateral, recurrent, and other inhibitory mechanisms. This analysis yields a novel model in which multiple interneuron types with distinct abundances, connectivity patterns, and physiologies complement one another to regulate M/TC activity and sensory processing.
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Affiliation(s)
- Shawn D Burton
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania; and .,Center for the Neural Basis of Cognition, Pittsburgh, Pennsylvania
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Cell-Type-Specific Modulation of Sensory Responses in Olfactory Bulb Circuits by Serotonergic Projections from the Raphe Nuclei. J Neurosci 2017; 36:6820-35. [PMID: 27335411 DOI: 10.1523/jneurosci.3667-15.2016] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Accepted: 05/17/2016] [Indexed: 12/15/2022] Open
Abstract
UNLABELLED Serotonergic neurons in the brainstem raphe nuclei densely innervate the olfactory bulb (OB), where they can modulate the initial representation and processing of olfactory information. Serotonergic modulation of sensory responses among defined OB cell types is poorly characterized in vivo Here, we used cell-type-specific expression of optical reporters to visualize how raphe stimulation alters sensory responses in two classes of GABAergic neurons of the mouse OB glomerular layer, periglomerular (PG) and short axon (SA) cells, as well as mitral/tufted (MT) cells carrying OB output to piriform cortex. In PG and SA cells, brief (1-4 s) raphe stimulation elicited a large increase in the magnitude of responses linked to inhalation of ambient air, as well as modest increases in the magnitude of odorant-evoked responses. Near-identical effects were observed when the optical reporter of glutamatergic transmission iGluSnFR was expressed in PG and SA cells, suggesting enhanced excitatory input to these neurons. In contrast, in MT cells imaged from the dorsal OB, raphe stimulation elicited a strong increase in resting GCaMP fluorescence with only a slight enhancement of inhalation-linked responses to odorant. Finally, optogenetically stimulating raphe serotonergic afferents in the OB had heterogeneous effects on presumptive MT cells recorded extracellularly, with an overall modest increase in resting and odorant-evoked responses during serotonergic afferent stimulation. These results suggest that serotonergic afferents from raphe dynamically modulate olfactory processing through distinct effects on multiple OB targets, and may alter the degree to which OB output is shaped by inhibition during behavior. SIGNIFICANCE STATEMENT Modulation of the circuits that process sensory information can profoundly impact how information about the external world is represented and perceived. This study investigates how the serotonergic system modulates the initial processing of olfactory information by the olfactory bulb, an obligatory relay between sensory neurons and cortex. We find that serotonergic projections from the raphe nuclei to the olfactory bulb dramatically enhance the responses of two classes of inhibitory interneurons to sensory input, that this effect is mediated by increased glutamatergic drive onto these neurons, and that serotonergic afferent activation alters the responses of olfactory bulb output neurons in vivo These results elucidate pathways by which neuromodulatory systems can dynamically regulate brain circuits during behavior.
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Experience-Dependent Plasticity in Accessory Olfactory Bulb Interneurons following Male-Male Social Interaction. J Neurosci 2017; 37:7240-7252. [PMID: 28659282 DOI: 10.1523/jneurosci.1031-17.2017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 06/01/2017] [Accepted: 06/22/2017] [Indexed: 12/19/2022] Open
Abstract
Chemosensory information processing in the mouse accessory olfactory system guides the expression of social behavior. After salient chemosensory encounters, the accessory olfactory bulb (AOB) experiences changes in the balance of excitation and inhibition at reciprocal synapses between mitral cells (MCs) and local interneurons. The mechanisms underlying these changes remain controversial. Moreover, it remains unclear whether MC-interneuron plasticity is unique to specific behaviors, such as mating, or whether it is a more general feature of the AOB circuit. Here, we describe targeted electrophysiological studies of AOB inhibitory internal granule cells (IGCs), many of which upregulate the immediate-early gene Arc after male-male social experience. Following the resident-intruder paradigm, Arc-expressing IGCs in acute AOB slices from resident males displayed stronger excitation than nonexpressing neighbors when sensory inputs were stimulated. The increased excitability of Arc-expressing IGCs was not correlated with changes in the strength or number of excitatory synapses with MCs but was instead associated with increased intrinsic excitability and decreased HCN channel-mediated IH currents. Consistent with increased inhibition by IGCs, MCs responded to sensory input stimulation with decreased depolarization and spiking following resident-intruder encounters. These results reveal that nonmating behaviors drive AOB inhibitory plasticity and indicate that increased MC inhibition involves intrinsic excitability changes in Arc-expressing interneurons.SIGNIFICANCE STATEMENT The accessory olfactory bulb (AOB) is a site of experience-dependent plasticity between excitatory mitral cells (MCs) and inhibitory internal granule cells (IGCs), but the physiological mechanisms and behavioral conditions driving this plasticity remain unclear. Here, we report studies of AOB neuronal plasticity following male-male social chemosensory encounters. We show that the plasticity-associated immediate-early gene Arc is selectively expressed in IGCs from resident males following the resident-intruder assay. After behavior, Arc-expressing IGCs are more strongly excited by sensory input stimulation and MC activation is suppressed. Arc-expressing IGCs do not show increased excitatory synaptic drive but instead show increased intrinsic excitability. These data indicate that MC-IGC plasticity is induced after male-male social chemosensory encounters, resulting in enhanced MC suppression by Arc-expressing IGCs.
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Marking S, Krosnowski K, Ogura T, Lin W. Dichotomous Distribution of Putative Cholinergic Interneurons in Mouse Accessory Olfactory Bulb. Front Neuroanat 2017; 11:10. [PMID: 28289379 PMCID: PMC5326757 DOI: 10.3389/fnana.2017.00010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 02/10/2017] [Indexed: 01/14/2023] Open
Abstract
Sensory information processing in the olfactory bulb (OB) relies on diverse populations of bulbar interneurons. In rodents, the accessory OB (AOB) is divided into two bulbar regions, the anterior (aAOB) and posterior (pAOB), which differ substantially in their circuitry connections and associated behaviors. We previously identified and characterized a large number of morphologically diverse cholinergic interneurons in the main OB (MOB) using transgenic mice to visualize the cell bodies of choline acetyltransferase (ChAT-expressing neurons and immunolabeling (Krosnowski et al., 2012)). However, whether there are cholinergic neurons in the AOB is controversial and there is no detailed characterization of such neurons. Using the same line of ChAT(bacterial artificial chromosome, BAC)-enhanced green fluorescent protein (eGFP) transgenic mice, we investigated cholinergic neurons in the AOB. We found significant differences in the number and location of GFP-expressing (GFP+), putative cholinergic interneurons between the aAOB and pAOB. The highest numbers of GFP+ interneurons were found in the aAOB glomerular layer (aGL) and pAOB mitral/tufted cell layer (pMCL). We also noted a high density of GFP+ interneurons encircling the border region of the pMCL. Interestingly, a small subset of glomeruli in the middle of the GL receives strong MCL GFP+ nerve processes. These local putative cholinergic-innervated glomeruli are situated just outside the aGL, setting the boundary between the pGL and aGL. Many but not all GFP+ neurons in the AOB were weakly labeled with antibodies against ChAT and vesicular acetylcholine transporter (VAChT). We further determined if these GFP+ interneurons differ from other previously characterized interneuron populations in the AOB and found that AOB GFP+ interneurons express neither GABAergic nor dopaminergic markers and most also do not express the glutamatergic marker. Similar to the cholinergic interneurons of the MOB, some AOB GFP+ interneurons express the calcium binding protein, calbindin-D28K. Moreover, exposure to either a male intruder or soiled bedding from a mating cage leads to an increase in the number of c-Fos-expressing MCL GFP+ neurons. Taken together, our data reveal a population of largely unidentified putative cholinergic neurons in the AOB. Their dichotomous distribution in the aAOB and pAOB suggests region-specific cholinergic involvement in olfactory information processing.
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Affiliation(s)
- Sarah Marking
- Department of Biological Sciences, University of Maryland, Baltimore County Baltimore, MD, USA
| | - Kurt Krosnowski
- Department of Biological Sciences, University of Maryland, Baltimore County Baltimore, MD, USA
| | - Tatsuya Ogura
- Department of Biological Sciences, University of Maryland, Baltimore County Baltimore, MD, USA
| | - Weihong Lin
- Department of Biological Sciences, University of Maryland, Baltimore County Baltimore, MD, USA
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Behavioral Status Influences the Dependence of Odorant-Induced Change in Firing on Prestimulus Firing Rate. J Neurosci 2017; 37:1835-1852. [PMID: 28093474 DOI: 10.1523/jneurosci.3132-16.2017] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2016] [Revised: 01/07/2017] [Accepted: 01/08/2017] [Indexed: 11/21/2022] Open
Abstract
The firing rate of the mitral/tufted cells in the olfactory bulb is known to undergo significant trial-to-trial variability and is affected by anesthesia. Here we ask whether odorant-elicited changes in firing rate depend on the rate before application of the stimulus in the awake and anesthetized mouse. We find that prestimulus firing rate varies widely on a trial-to-trial basis and that the stimulus-induced change in firing rate decreases with increasing prestimulus firing rate. Interestingly, this prestimulus firing rate dependence was different when the behavioral task did not involve detecting the valence of the stimulus. Finally, when the animal was learning to associate the odor with reward, the prestimulus firing rate was smaller for false alarms compared with correct rejections, suggesting that intrinsic activity reflects the anticipatory status of the animal. Thus, in this sensory modality, changes in behavioral status alter the intrinsic prestimulus activity, leading to a change in the responsiveness of the second-order neurons. We speculate that this trial-to-trial variability in odorant responses reflects sampling of the massive parallel input by subsets of mitral cells.SIGNIFICANCE STATEMENT The olfactory bulb must deal with processing massive parallel input from ∼1200 distinct olfactory receptors. In contrast, the visual system receives input from a small number of photoreceptors and achieves recognition of complex stimuli by allocating processing for distinct spatial locations to different brain areas. Here we find that the change in firing rate elicited by the odorant in second-order mitral cells depends on the intrinsic activity leading to a change of magnitude in the responsiveness of these neurons relative to this prestimulus activity. Further, we find that prestimulus firing rate is influenced by behavioral status. This suggests that there is top-down modulation allowing downstream brain processing areas to perform dynamic readout of olfactory information.
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Olfactory Bulb Deep Short-Axon Cells Mediate Widespread Inhibition of Tufted Cell Apical Dendrites. J Neurosci 2016; 37:1117-1138. [PMID: 28003347 DOI: 10.1523/jneurosci.2880-16.2016] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 11/14/2016] [Accepted: 12/03/2016] [Indexed: 01/10/2023] Open
Abstract
In the main olfactory bulb (MOB), the first station of sensory processing in the olfactory system, GABAergic interneuron signaling shapes principal neuron activity to regulate olfaction. However, a lack of known selective markers for MOB interneurons has strongly impeded cell-type-selective investigation of interneuron function. Here, we identify the first selective marker of glomerular layer-projecting deep short-axon cells (GL-dSACs) and investigate systematically the structure, abundance, intrinsic physiology, feedforward sensory input, neuromodulation, synaptic output, and functional role of GL-dSACs in the mouse MOB circuit. GL-dSACs are located in the internal plexiform layer, where they integrate centrifugal cholinergic input with highly convergent feedforward sensory input. GL-dSAC axons arborize extensively across the glomerular layer to provide highly divergent yet selective output onto interneurons and principal tufted cells. GL-dSACs are thus capable of shifting the balance of principal tufted versus mitral cell activity across large expanses of the MOB in response to diverse sensory and top-down neuromodulatory input. SIGNIFICANCE STATEMENT The identification of cell-type-selective molecular markers has fostered tremendous insight into how distinct interneurons shape sensory processing and behavior. In the main olfactory bulb (MOB), inhibitory circuits regulate the activity of principal cells precisely to drive olfactory-guided behavior. However, selective markers for MOB interneurons remain largely unknown, limiting mechanistic understanding of olfaction. Here, we identify the first selective marker of a novel population of deep short-axon cell interneurons with superficial axonal projections to the sensory input layer of the MOB. Using this marker, together with immunohistochemistry, acute slice electrophysiology, and optogenetic circuit mapping, we reveal that this novel interneuron population integrates centrifugal cholinergic input with broadly tuned feedforward sensory input to modulate principal cell activity selectively.
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Genovese F, Bauersachs HG, Gräßer I, Kupke J, Magin L, Daiber P, Nakajima J, Möhrlen F, Messlinger K, Frings S. Possible role of calcitonin gene-related peptide in trigeminal modulation of glomerular microcircuits of the rodent olfactory bulb. Eur J Neurosci 2016; 45:587-600. [PMID: 27891688 DOI: 10.1111/ejn.13490] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 11/17/2016] [Accepted: 11/21/2016] [Indexed: 11/29/2022]
Abstract
Chemosensation in the mammalian nose comprises detection of odorants, irritants and pheromones. While the traditional view assigned one distinct sub-system to each stimulus type, recent research has produced a more complex picture. Odorants are not only detected by olfactory sensory neurons but also by the trigeminal system. Irritants, in turn, may have a distinct odor, and some pheromones are detected by the olfactory epithelium. Moreover, it is well established that irritants change odor perception and vice versa. A wealth of psychophysical evidence on olfactory-trigeminal interactions in humans contrasts with a paucity of structural insight. In particular, it is unclear whether the two systems communicate just by sharing stimuli, or whether neuronal connections mediate cross-modal signaling. One connection could exist in the olfactory bulb that performs the primary processing of olfactory signals and receives trigeminal innervation. In the present study, neuroanatomical tracing of the mouse ethmoid system illustrates how peptidergic fibers enter the glomerular layer of the olfactory bulb, where local microcircuits process and filter the afferent signal. Biochemical assays reveal release of calcitonin gene-related peptide from olfactory bulb slices and attenuation of cAMP signaling by the neuropeptide. In the non-stimulated tissue, the neuropeptide specifically inhibited the basal activity of calbindin-expressing periglomerular interneurons, but did not affect the basal activity of neurons expressing calretinin, parvalbumin, or tyrosine hydroxylase, nor the activity of astrocytes. This study represents a first step towards understanding trigeminal neuromodulation of olfactory-bulb microcircuits and provides a working hypothesis for trigeminal inhibition of olfactory signal processing. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Federica Genovese
- Department of Animal Molecular Physiology, Centre of Organismal Studies, Heidelberg University, Heidelberg, Germany
| | - Hanke Gwendolyn Bauersachs
- Department of Animal Molecular Physiology, Centre of Organismal Studies, Heidelberg University, Heidelberg, Germany
| | - Ines Gräßer
- Department of Animal Molecular Physiology, Centre of Organismal Studies, Heidelberg University, Heidelberg, Germany
| | - Janina Kupke
- Department of Animal Molecular Physiology, Centre of Organismal Studies, Heidelberg University, Heidelberg, Germany
| | - Laila Magin
- Department of Animal Molecular Physiology, Centre of Organismal Studies, Heidelberg University, Heidelberg, Germany
| | - Philipp Daiber
- Interfacultary Biomedical Faculty, Heidelberg University, Heidelberg, Germany
| | - Julika Nakajima
- Institute of Physiology and Pathophysiology, University of Erlangen-Nuernberg, Erlangen, Germany
| | - Frank Möhrlen
- Department of Animal Molecular Physiology, Centre of Organismal Studies, Heidelberg University, Heidelberg, Germany
| | - Karl Messlinger
- Institute of Physiology and Pathophysiology, University of Erlangen-Nuernberg, Erlangen, Germany
| | - Stephan Frings
- Department of Animal Molecular Physiology, Centre of Organismal Studies, Heidelberg University, Heidelberg, Germany
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