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Lorenzon P, Antos K, Tripathi A, Vedin V, Berghard A, Medini P. In vivo spontaneous activity and coital-evoked inhibition of mouse accessory olfactory bulb output neurons. iScience 2023; 26:107545. [PMID: 37664596 PMCID: PMC10470370 DOI: 10.1016/j.isci.2023.107545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 04/11/2023] [Accepted: 08/01/2023] [Indexed: 09/05/2023] Open
Abstract
Little is known about estrous effects on brain microcircuits. We examined the accessory olfactory bulb (AOB) in vivo, in anesthetized naturally cycling females, as model microcircuit receiving coital somatosensory information. Whole-cell recordings demonstrate that output neurons are relatively hyperpolarized in estrus and unexpectedly fire high frequency bursts of action potentials. To mimic coitus, a calibrated artificial vagino-cervical stimulation (aVCS) protocol was devised. aVCS evoked stimulus-locked local field responses in the interneuron layer independent of estrous stage. The response is sensitive to α1-adrenergic receptor blockade, as expected since aVCS increases norepinephrine release in AOB. Intriguingly, only in estrus does aVCS inhibit AOB spike output. Estrus-specific output reduction coincides with prolonged aVCS activation of inhibitory interneurons. Accordingly, in estrus the AOB microcircuit sets the stage for coital stimulation to inhibit the output neurons, possibly via high frequency bursting-dependent enhancement of reciprocal synapse efficacy between inter- and output neurons.
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Affiliation(s)
- Paolo Lorenzon
- Department of Integrative Medical Biology, Umeå University, SE90187 Umeå, Sweden
| | - Kamil Antos
- Department of Integrative Medical Biology, Umeå University, SE90187 Umeå, Sweden
| | - Anushree Tripathi
- Department of Integrative Medical Biology, Umeå University, SE90187 Umeå, Sweden
| | - Viktoria Vedin
- Department of Molecular Biology, Umeå University, SE90187 Umeå, Sweden
| | - Anna Berghard
- Department of Molecular Biology, Umeå University, SE90187 Umeå, Sweden
| | - Paolo Medini
- Department of Integrative Medical Biology, Umeå University, SE90187 Umeå, Sweden
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Zheng N, Wang ZZ, Wang SW, Yang FJ, Zhu XT, Lu C, Manyande A, Rao XP, Xu FQ. Co-localization of two-color rAAV2-retro confirms the dispersion characteristics of efferent projections of mitral cells in mouse accessory olfactory bulb. Zool Res 2020; 41:148-156. [PMID: 31945810 PMCID: PMC7109009 DOI: 10.24272/j.issn.2095-8137.2020.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The accessory olfactory bulb (AOB), located at the posterior dorsal aspect of the main olfactory bulb (MOB), is the first brain relay of the accessory olfactory system (AOS), which can parallelly detect and process volatile and nonvolatile social chemosignals and mediate different sexual and social behaviors with the main olfactory system (MOS). However, due to its anatomical location and absence of specific markers, there is a lack of research on the internal and external neural circuits of the AOB. This issue was addressed by single-color labeling and fluorescent double labeling using retrograde rAAVs injected into the bed nucleus of the stria terminalis (BST), anterior cortical amygdalar area (ACo), medial amygdaloid nucleus (MeA), and posteromedial cortical amygdaloid area (PMCo) in mice. We demonstrated the effectiveness of this AOB projection neuron labeling method and showed that the mitral cells of the AOB exhibited efferent projection dispersion characteristics similar to those of the MOB. Moreover, there were significant differences in the number of neurons projected to different brain regions, which indicated that each mitral cell in the AOB could project to a different number of neurons in different cortices. These results provide a circuitry basis to help understand the mechanism by which pheromone information is encoded and decoded in the AOS.
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Affiliation(s)
- Ning Zheng
- 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, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, Hubei 430071, China.,University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Zhi-Zhong Wang
- Department of Automation, School of Electrical Engineering, Zhengzhou University, Zhengzhou, Henan 450001, China
| | - Song-Wei Wang
- Department of Automation, School of Electrical Engineering, Zhengzhou University, Zhengzhou, Henan 450001, China
| | - Fang-Jia Yang
- School of Life Science, Wuhan University, Wuhan, Hubei 430072, China
| | - Xu-Tao Zhu
- 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, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, Hubei 430071, China
| | - Chen Lu
- School of Life Science, Wuhan University, Wuhan, Hubei 430072, China
| | - Anne Manyande
- School of Human and Social Sciences, University of West London, Middlesex TW89GA, UK
| | - Xiao-Ping 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, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, Hubei 430071, China. E-mail:
| | - Fu-Qiang 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, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, Hubei 430071, China.,University of the Chinese Academy of Sciences, Beijing 100049, China.,Divisions of Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Wuhan, Hubei 430074, China. E-mail:
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Zhang X, Meeks JP. Paradoxically Sparse Chemosensory Tuning in Broadly Integrating External Granule Cells in the Mouse Accessory Olfactory Bulb. J Neurosci 2020; 40:5247-5263. [PMID: 32503886 PMCID: PMC7329303 DOI: 10.1523/jneurosci.2238-19.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 04/20/2020] [Accepted: 04/23/2020] [Indexed: 12/20/2022] Open
Abstract
The accessory olfactory bulb (AOB), the first neural circuit in the mouse accessory olfactory system, is critical for interpreting social chemosignals. Despite its importance, AOB information processing is poorly understood compared with the main olfactory bulb (MOB). Here, we sought to fill gaps in the understanding of AOB interneuron function. We used 2-photon GCaMP6f Ca2+ imaging in an ex vivo preparation to study chemosensory tuning in AOB external granule cells (EGCs), interneurons hypothesized to broadly inhibit activity in excitatory mitral cells (MCs). In ex vivo preparations from mice of both sexes, we measured MC and EGC tuning to natural chemosignal blends and monomolecular ligands, finding that EGC tuning was sparser, not broader, than upstream MCs. Simultaneous electrophysiological recording and Ca2+ imaging showed no differences in GCaMP6f-to-spiking relationships in these cell types during simulated sensory stimulation, suggesting that measured EGC sparseness was not due to cell type-dependent variability in GCaMP6f performance. Ex vivo patch-clamp recordings revealed that EGC subthreshold responsivity was far broader than indicated by GCaMP6f Ca2+ imaging, and that monomolecular ligands rarely elicited EGC spiking. These results indicate that EGCs are selectively engaged by chemosensory blends, suggesting different roles for EGCs than analogous interneurons in the MOB.SIGNIFICANCE STATEMENT The mouse accessory olfactory system (AOS) interprets social chemosignals, but we poorly understand AOS information processing. Here, we investigate the functional properties of external granule cells (EGCs), a major class of interneurons in the accessory olfactory bulb (AOB). We hypothesized that EGCs, which are densely innervated by excitatory mitral cells (MCs), would show broad chemosensory tuning, suggesting a role in divisive normalization. Using ex vivo GCaMP6f imaging, we found that EGCs were instead more sparsely tuned than MCs. This was not due to weaker GCaMP6f signaling in EGCs than in MCs. Instead, we found that many MC-activating chemosignals caused only subthreshold EGC responses. This indicates a different role for AOB EGCs compared with analogous cells in the main olfactory bulb.
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Affiliation(s)
- Xingjian Zhang
- University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Julian P Meeks
- University of Texas Southwestern Medical Center, Dallas, Texas 75390
- University of Rochester School of Medicine and Dentistry, Rochester, NY, 14642
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Mohrhardt J, Nagel M, Fleck D, Ben-Shaul Y, Spehr M. Signal Detection and Coding in the Accessory Olfactory System. Chem Senses 2019; 43:667-695. [PMID: 30256909 PMCID: PMC6211456 DOI: 10.1093/chemse/bjy061] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
In many mammalian species, the accessory olfactory system plays a central role in guiding behavioral and physiological responses to social and reproductive interactions. Because of its relatively compact structure and its direct access to amygdalar and hypothalamic nuclei, the accessory olfactory pathway provides an ideal system to study sensory control of complex mammalian behavior. During the last several years, many studies employing molecular, behavioral, and physiological approaches have significantly expanded and enhanced our understanding of this system. The purpose of the current review is to integrate older and newer studies to present an updated and comprehensive picture of vomeronasal signaling and coding with an emphasis on early accessory olfactory system processing stages. These include vomeronasal sensory neurons in the vomeronasal organ, and the circuitry of the accessory olfactory bulb. Because the overwhelming majority of studies on accessory olfactory system function employ rodents, this review is largely focused on this phylogenetic order, and on mice in particular. Taken together, the emerging view from both older literature and more recent studies is that the molecular, cellular, and circuit properties of chemosensory signaling along the accessory olfactory pathway are in many ways unique. Yet, it has also become evident that, like the main olfactory system, the accessory olfactory system also has the capacity for adaptive learning, experience, and state-dependent plasticity. In addition to describing what is currently known about accessory olfactory system function and physiology, we highlight what we believe are important gaps in our knowledge, which thus define exciting directions for future investigation.
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Affiliation(s)
- Julia Mohrhardt
- Department of Chemosensation, Institute for Biology II, RWTH Aachen University, Aachen, Germany
| | - Maximilian Nagel
- Department of Chemosensation, Institute for Biology II, RWTH Aachen University, Aachen, Germany
| | - David Fleck
- Department of Chemosensation, Institute for Biology II, RWTH Aachen University, Aachen, Germany
| | - Yoram Ben-Shaul
- Department of Medical Neurobiology, School of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Marc Spehr
- Department of Chemosensation, Institute for Biology II, RWTH Aachen University, Aachen, Germany
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Noguchi T, Sasajima H, Miyazono S, Kashiwayanagi M. Similar rate of information transfer on stimulus intensity in accessory and main olfactory bulb output neurons. Neurosci Lett 2014; 576:56-61. [PMID: 24909616 DOI: 10.1016/j.neulet.2014.05.058] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 05/15/2014] [Accepted: 05/29/2014] [Indexed: 01/29/2023]
Abstract
Recently, evidence has accumulated that the vomeronasal system cooperates with the main olfactory system to process volatile cues that regulate the animal's behavior. This is contradictory to the traditional view that the vomeronasal system is quite different from the main olfactory system in the time scale of information processing. Particularly, the firing rate of mitral/tufted cells in the accessory olfactory bulb (MTAOB) is known to be significantly lower than that of mitral cells in the main olfactory bulb (MCMOB). To address this question of whether the low-frequency firing in MTAOB carries less information than the high-frequency firing in MCMOB in the early stages of stimulation, we compared MTAOB and MCMOB for their firing mechanisms and information transfer characteristics. A model computation demonstrated that the inherent channel kinetics of MTAOB was responsible for their firing at a lower frequency than MCMOB. Nevertheless, our analysis suggested that MTAOB were comparable to MCMOB in both the amount and speed of information transfer about depolarizing current intensity immediately after current injection onset (<200ms). Our results support a hypothesis of simultaneous processing of common cues in both systems.
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Affiliation(s)
- Tomohiro Noguchi
- Department of Sensory Physiology, Asahikawa Medical University, Midorigaokahigashi 2-1-1-1, Asahikawa 078-8510, Japan.
| | - Hitoshi Sasajima
- Department of Sensory Physiology, Asahikawa Medical University, Midorigaokahigashi 2-1-1-1, Asahikawa 078-8510, Japan.
| | - Sadaharu Miyazono
- Department of Sensory Physiology, Asahikawa Medical University, Midorigaokahigashi 2-1-1-1, Asahikawa 078-8510, Japan.
| | - Makoto Kashiwayanagi
- Department of Sensory Physiology, Asahikawa Medical University, Midorigaokahigashi 2-1-1-1, Asahikawa 078-8510, Japan.
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Oboti L, Peretto P. How neurogenesis finds its place in a hardwired sensory system. Front Neurosci 2014; 8:102. [PMID: 24847202 PMCID: PMC4023038 DOI: 10.3389/fnins.2014.00102] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 04/18/2014] [Indexed: 02/05/2023] Open
Abstract
So far most studies on adult neurogenesis aimed to unravel mechanisms and molecules regulating the integration of newly generated neurons in the mature brain parenchyma. The exceedingly abundant amount of results that followed, rather than being beneficial in the perspective of brain repair, provided a clear evidence that adult neurogenesis constitutes a necessary feature to the correct functioning of the hosting brain regions. In particular, the rodent olfactory system represents a privileged model to study how neuronal plasticity and neurogenesis interact with sensory functions. Until recently, the vomeronasal system (VNS) has been commonly described as being specialized in the detection of innate chemosignals. Accordingly, its circuitry has been considered necessarily stable, if not hard-wired, in order to allow stereotyped behavioral responses. However, both first and second order projections of the rodent VNS continuously change their synaptic connectivity due to ongoing postnatal and adult neurogenesis. How the functional integrity of a neuronal circuit is maintained while newborn neurons are continuously added—or lost—is a fundamental question for both basic and applied neuroscience. The VNS is proposed as an alternative model to answer such question. Hereby the underlying motivations will be reviewed.
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Affiliation(s)
- Livio Oboti
- Children's National Health System, Center for Neuroscience Research Washington, DC, USA
| | - Paolo Peretto
- Department of Life Sciences and Systems Biology, Neuroscience Institute Cavalieri Ottolenghi, University of Torino Orbassano, Italy
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