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Sample records for model olfactory bulb

  1. Olfactory bulb as an alternative in neurotransplantation

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    Руслан Романович Новиков

    2015-05-01

    Full Text Available The article examines the ethical and legal aspects of transplantation of embryonic neural tissue, structure of the rat olfactory bulb. It is given substantiation for its use as a possible alternative version of the embryonic neural tissue at damage in the cerebral hemispheres in the experiment.Materials and methods. Detailed description of the fault model of the cerebral hemispheres of the brain of rats, olfactory bulb biopsy procedure, cultivation of olfactory bulb suspension and fetal neural tissue, comparison of the functional aspects of transplantation of the olfactory bulb and the embryonic neural tissue.Results. The obtained data are similar to structure of olfactory bulb and fetal tissues during culturing. Recovery in the motor areas varies by the time factor and less intense in the group of the olfactory bulb and the group without tissue transplantation.Conclusions. Comparative analysis of the effectiveness of transplantation of embryonic neural tissue and olfactory bulb in the injured brain allows us to speak about the positive results of these groups to the difference in the duration of the recovery process

  2. Distributed organization of a brain microcircuit analysed by three-dimensional modeling: the olfactory bulb

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    Michele eMigliore

    2014-04-01

    Full Text Available The functional consequences of the laminar organization observed in cortical systems cannot be easily studied using standard experimental techniques, abstract theoretical representations, or dimensionally reduced models built from scratch. To solve this problem we have developed a full implementation of an olfactory bulb microcircuit using realistic three-dimensional inputs, cell morphologies, and network connectivity. The results provide new insights into the relations between the functional properties of individual cells and the networks in which they are embedded. To our knowledge, this is the first model of the mitral-granule cell network to include a realistic representation of the experimentally-recorded complex spatial patterns elicited in the glomerular layer by natural odor stimulation. Although the olfactory bulb, due to its organization, has unique advantages with respect to other brain systems, the method is completely general, and can be integrated with more general approaches to other systems. The model makes experimentally testable predictions on distributed processing and on the differential backpropagation of somatic action potentials in each lateral dendrite following odor learning, providing a powerful three-dimensional framework for investigating the functions of brain microcircuits.

  3. Bifurcation analysis of oscillating network model of pattern recognition in the rabbit olfactory bulb

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    Baird, Bill

    1986-08-01

    A neural network model describing pattern recognition in the rabbit olfactory bulb is analysed to explain the changes in neural activity observed experimentally during classical Pavlovian conditioning. EEG activity recorded from an 8×8 arry of 64 electrodes directly on the surface on the bulb shows distinct spatial patterns of oscillation that correspond to the animal's recognition of different conditioned odors and change with conditioning to new odors. The model may be considered a variant of Hopfield's model of continuous analog neural dynamics. Excitatory and inhibitory cell types in the bulb and the anatomical architecture of their connection requires a nonsymmetric coupling matrix. As the mean input level rises during each breath of the animal, the system bifurcates from homogenous equilibrium to a spatially patterned oscillation. The theory of multiple Hopf bifurcations is employed to find coupled equations for the amplitudes of these unstable oscillatory modes independent of frequency. This allows a view of stored periodic attractors as fixed points of a gradient vector field and thereby recovers the more familiar dynamical systems picture of associative memory.

  4. Caffeine and the olfactory bulb.

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    Hadfield, M G

    1997-08-01

    Caffeine, a popular CNS stimulant, is the most widely used neuroactive drug. Present in coffee, tea, chocolate, and soft drinks as well as over-the-counter and prescription medications, it influences millions of users. This agent has achieved recent notoriety because its dependency consequences and addictive potential have been re-examined and emphasized. Caffeine's central actions are thought to be mediated through adenosine (A) receptors and monoamine neurotransmitters. The present article suggests that the olfactory bulb (OB) may be an important site in the brain that is responsible for caffeine's central actions in several species. This conclusion is based on the extraordinarily robust and selective effects of caffeine on norepinephrine (NE), dopamine (DA), and particularly serotonin (5HT) utilization in the OB of mice. We believe that these phenomena should be given appropriate consideration as a basis for caffeine's central actions, even in primates. Concurrently, we review a rich rodent literature concerned with A, 5HT, NE, and DA receptors in the OB and related structures along with other monoamine parameters. We also review a more limited literature concerned with the primate OB. Finally, we cite the literature that treats the dependency and addictive effects of caffeine in humans, and relate the findings to possible olfactory mechanisms.

  5. Proteomic Analysis of the Human Olfactory Bulb.

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    Dammalli, Manjunath; Dey, Gourav; Madugundu, Anil K; Kumar, Manish; Rodrigues, Benvil; Gowda, Harsha; Siddaiah, Bychapur Gowrishankar; Mahadevan, Anita; Shankar, Susarla Krishna; Prasad, Thottethodi Subrahmanya Keshava

    2017-08-01

    The importance of olfaction to human health and disease is often underappreciated. Olfactory dysfunction has been reported in association with a host of common complex diseases, including neurological diseases such as Alzheimer's disease and Parkinson's disease. For health, olfaction or the sense of smell is also important for most mammals, for optimal engagement with their environment. Indeed, animals have developed sophisticated olfactory systems to detect and interpret the rich information presented to them to assist in day-to-day activities such as locating food sources, differentiating food from poisons, identifying mates, promoting reproduction, avoiding predators, and averting death. In this context, the olfactory bulb is a vital component of the olfactory system receiving sensory information from the axons of the olfactory receptor neurons located in the nasal cavity and the first place that processes the olfactory information. We report in this study original observations on the human olfactory bulb proteome in healthy subjects, using a high-resolution mass spectrometry-based proteomic approach. We identified 7750 nonredundant proteins from human olfactory bulbs. Bioinformatics analysis of these proteins showed their involvement in biological processes associated with signal transduction, metabolism, transport, and olfaction. These new observations provide a crucial baseline molecular profile of the human olfactory bulb proteome, and should assist the future discovery of biomarker proteins and novel diagnostics associated with diseases characterized by olfactory dysfunction.

  6. Changes in olfactory bulb volume following lateralized olfactory training.

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    Negoias, S; Pietsch, K; Hummel, T

    2017-08-01

    Repeated exposure to odors modifies olfactory function. Consequently, "olfactory training" plays a significant role in hyposmia treatment. In addition, numerous studies show that the olfactory bulb (OB) volume changes in disorders associated with olfactory dysfunction. Aim of this study was to investigate whether and how olfactory bulb volume changes in relation to lateralized olfactory training in healthy people. Over a period of 4 months, 97 healthy participants (63 females and 34 males, mean age: 23.74 ± 4.16 years, age range: 19-43 years) performed olfactory training by exposing the same nostril twice a day to 4 odors (lemon, rose, eucalyptus and cloves) while closing the other nostril. Before and after olfactory training, magnetic resonance imaging (MRI) scans were performed to measure OB volume. Furthermore, participants underwent lateralized odor threshold and odor identification testing using the "Sniffin' Sticks" test battery.OB volume increased significantly after olfactory training (11.3 % and 13.1 % respectively) for both trained and untrained nostril. No significant effects of sex, duration and frequency of training or age of the subjects were seen. Interestingly, PEA odor thresholds worsened after training, while olfactory identification remained unchanged.These data show for the first time in humans that olfactory training may involve top-down process, which ultimately lead to a bilateral increase in olfactory bulb volume.

  7. Cortical feedback control of olfactory bulb circuits.

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    Boyd, Alison M; Sturgill, James F; Poo, Cindy; Isaacson, Jeffry S

    2012-12-20

    Olfactory cortex pyramidal cells integrate sensory input from olfactory bulb mitral and tufted (M/T) cells and project axons back to the bulb. However, the impact of cortical feedback projections on olfactory bulb circuits is unclear. Here, we selectively express channelrhodopsin-2 in olfactory cortex pyramidal cells and show that cortical feedback projections excite diverse populations of bulb interneurons. Activation of cortical fibers directly excites GABAergic granule cells, which in turn inhibit M/T cells. However, we show that cortical inputs preferentially target short axon cells that drive feedforward inhibition of granule cells. In vivo, activation of olfactory cortex that only weakly affects spontaneous M/T cell firing strongly gates odor-evoked M/T cell responses: cortical activity suppresses odor-evoked excitation and enhances odor-evoked inhibition. Together, these results indicate that although cortical projections have diverse actions on olfactory bulb microcircuits, the net effect of cortical feedback on M/T cells is an amplification of odor-evoked inhibition. Copyright © 2012 Elsevier Inc. All rights reserved.

  8. Olfactory bulb encoding during learning under anaesthesia

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    Alister U Nicol

    2014-06-01

    Full Text Available Neural plasticity changes within the olfactory bulb are important for olfactory learning, although how neural encoding changes support new associations with specific odours and whether they can be investigated under anaesthesia, remain unclear. Using the social transmission of food preference olfactory learning paradigm in mice in conjunction with in vivo microdialysis sampling we have shown firstly that a learned preference for a scented food odour smelled on the breath of a demonstrator animal occurs under isofluorane anaesthesia. Furthermore, subsequent exposure to this cued odour under anaesthesia promotes the same pattern of increased release of glutamate and GABA in the olfactory bulb as previously found in conscious animals following olfactory learning, and evoked GABA release was positively correlated with the amount of scented food eaten. In a second experiment, multiarray (24 electrodes electrophysiological recordings were made from olfactory bulb mitral cells under isofluorane anaesthesia before, during and after a novel scented food odour was paired with carbon disulfide. Results showed significant increases in overall firing frequency to the cued-odour during and after learning and decreases in response to an uncued odour. Analysis of patterns of changes in individual neurons revealed that a substantial proportion (>50% of them significantly changed their response profiles during and after learning with most of those previously inhibited becoming excited. A large number of cells exhibiting no response to the odours prior to learning were either excited or inhibited afterwards. With the uncued odour many previously responsive cells became unresponsive or inhibited. Learning associated changes only occurred in the posterior part of the olfactory bulb. Thus olfactory learning under anaesthesia promotes extensive, but spatially distinct, changes in mitral cell networks to both cued and uncued odours as well as in evoked glutamate and

  9. Human olfactory bulb neural stem cells mitigate movement disorders in a rat model of Parkinson's disease.

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    Marei, Hany E S; Lashen, Samah; Farag, Amany; Althani, Asmaa; Afifi, Nahla; A, Abd-Elmaksoud; Rezk, Shaymaa; Pallini, Roberto; Casalbore, Patrizia; Cenciarelli, Carlo

    2015-07-01

    Parkinson's disease (PD) is a neurological disorder characterized by the loss of midbrain dopaminergic (DA) neurons. Neural stem cells (NSCs) are multipotent stem cells that are capable of differentiating into different neuronal and glial elements. The production of DA neurons from NSCs could potentially alleviate behavioral deficits in Parkinsonian patients; timely intervention with NSCs might provide a therapeutic strategy for PD. We have isolated and generated highly enriched cultures of neural stem/progenitor cells from the human olfactory bulb (OB). If NSCs can be obtained from OB, it would alleviate ethical concerns associated with the use of embryonic tissue, and provide an easily accessible cell source that would preclude the need for invasive brain surgery. Following isolation and culture, olfactory bulb neural stem cells (OBNSCs) were genetically engineered to express hNGF and GFP. The hNFG-GFP-OBNSCs were transplanted into the striatum of 6-hydroxydopamin (6-OHDA) Parkinsonian rats. The grafted cells survived in the lesion environment for more than eight weeks after implantation with no tumor formation. The grafted cells differentiated in vivo into oligodendrocyte-like (25 ± 2.88%), neuron-like (52.63 ± 4.16%), and astrocyte -like (22.36 ± 1.56%) lineages, which we differentiated based on morphological and immunohistochemical criteria. Transplanted rats exhibited a significant partial correction in stepping and placing in non-pharmacological behavioral tests, pole and rotarod tests. Taken together, our data encourage further investigations of the possible use of OBNSCs as a promising cell-based therapeutic strategy for Parkinson's disease. © 2014 Wiley Periodicals, Inc.

  10. Olfactory Perceptual Learning Requires Action of Noradrenaline in the Olfactory Bulb: Comparison with Olfactory Associative Learning

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    Vinera, Jennifer; Kermen, Florence; Sacquet, Joëlle; Didier, Anne; Mandairon, Nathalie; Richard, Marion

    2015-01-01

    Noradrenaline contributes to olfactory-guided behaviors but its role in olfactory learning during adulthood is poorly documented. We investigated its implication in olfactory associative and perceptual learning using local infusion of mixed a1-ß adrenergic receptor antagonist (labetalol) in the adult mouse olfactory bulb. We reported that…

  11. A Mathematical Model of the Olfactory Bulb for the Selective Adaptation Mechanism in the Rodent Olfactory System.

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    Soh, Zu; Nishikawa, Shinya; Kurita, Yuichi; Takiguchi, Noboru; Tsuji, Toshio

    2016-01-01

    To predict the odor quality of an odorant mixture, the interaction between odorants must be taken into account. Previously, an experiment in which mice discriminated between odorant mixtures identified a selective adaptation mechanism in the olfactory system. This paper proposes an olfactory model for odorant mixtures that can account for selective adaptation in terms of neural activity. The proposed model uses the spatial activity pattern of the mitral layer obtained from model simulations to predict the perceptual similarity between odors. Measured glomerular activity patterns are used as input to the model. The neural interaction between mitral cells and granular cells is then simulated, and a dissimilarity index between odors is defined using the activity patterns of the mitral layer. An odor set composed of three odorants is used to test the ability of the model. Simulations are performed based on the odor discrimination experiment on mice. As a result, we observe that part of the neural activity in the glomerular layer is enhanced in the mitral layer, whereas another part is suppressed. We find that the dissimilarity index strongly correlates with the odor discrimination rate of mice: r = 0.88 (p = 0.019). We conclude that our model has the ability to predict the perceptual similarity of odorant mixtures. In addition, the model also accounts for selective adaptation via the odor discrimination rate, and the enhancement and inhibition in the mitral layer may be related to this selective adaptation.

  12. Organization and distribution of glomeruli in the bowhead whale olfactory bulb

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    Takushi Kishida

    2015-04-01

    Full Text Available Although modern baleen whales (Mysticeti retain a functional olfactory system that includes olfactory bulbs, cranial nerve I and olfactory receptor genes, their olfactory capabilities have been reduced to a great degree. This reduction likely occurred as a selective response to their fully aquatic lifestyle. The glomeruli that occur in the olfactory bulb can be divided into two non-overlapping domains, a dorsal domain and a ventral domain. Recent molecular studies revealed that all modern whales have lost olfactory receptor genes and marker genes that are specific to the dorsal domain. Here we show that olfactory bulbs of bowhead whales (Balaena mysticetus lack glomeruli on the dorsal side, consistent with the molecular data. In addition, we estimate that there are more than 4,000 glomeruli elsewhere in the bowhead whale olfactory bulb, which is surprising given that bowhead whales possess only 80 intact olfactory receptor genes. Olfactory sensory neurons that express the same olfactory receptors in rodents generally project to two specific glomeruli in an olfactory bulb, implying an approximate 1:2 ratio of the number of olfactory receptors to the number of glomeruli. Here we show that this ratio does not apply to bowhead whales, reiterating the conceptual limits of using rodents as model organisms for understanding the initial coding of odor information among mammals.

  13. Selenomethionine Ameliorates Neuropathology in the Olfactory Bulb of a Triple Transgenic Mouse Model of Alzheimer’s Disease

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    Zhong-Hao Zhang

    2016-09-01

    Full Text Available Olfactory dysfunction is an early and common symptom in Alzheimer′s disease (AD and is reported to be related to several pathologic changes, including the deposition of Aβ and hyperphosphorylated tau protein as well as synaptic impairment. Selenomethionine (Se-Met, the major form of selenium in animals and humans, may be a promising therapeutic option for AD as it decreases the deposition of Aβ and tau hyperphosphorylation in a triple transgenic mouse model of AD (3× Tg-AD. In this study, 4-month-old AD mice were treated with 6 µg/mL Se-Met in drinking water for 12 weeks and the effect of Se-Met on neuropathological deficits in olfactory bulb (OB of 3× Tg-AD mice was investigated. The administration of Se-Met effectively decreased the production and deposition of Aβ by inhibiting β-site amyloid precursor protein cleaving enzyme 1 (BACE1-regulated amyloid precursor protein (APP processing and reduced the level of total tau and phosphorylated tau, which depended on depressing the activity and expression of glycogen synthase kinase-3β (GSK-3β and cyclin-dependent kinase 5 (CDK5. Meanwhile, Se-Met reduced glial activation, relieved neuroinflammation and attenuated neuronal cell death in the OB of AD mice. So Se-Met could improve pathologic changes of AD in the OB, which further demonstrated the potential therapeutic effect of Se-Met in AD.

  14. DNA polymerase β decrement triggers death of olfactory bulb cells and impairs olfaction in a mouse model of Alzheimer's disease.

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    Misiak, Magdalena; Vergara Greeno, Rebeca; Baptiste, Beverly A; Sykora, Peter; Liu, Dong; Cordonnier, Stephanie; Fang, Evandro F; Croteau, Deborah L; Mattson, Mark P; Bohr, Vilhelm A

    2017-02-01

    Alzheimer's disease (AD) involves the progressive degeneration of neurons critical for learning and memory. In addition, patients with AD typically exhibit impaired olfaction associated with neuronal degeneration in the olfactory bulb (OB). Because DNA base excision repair (BER) is reduced in brain cells during normal aging and AD, we determined whether inefficient BER due to reduced DNA polymerase-β (Polβ) levels renders OB neurons vulnerable to degeneration in the 3xTgAD mouse model of AD. We interrogated OB histopathology and olfactory function in wild-type and 3xTgAD mice with normal or reduced Polβ levels. Compared to wild-type control mice, Polβ heterozygous (Polβ +/- ), and 3xTgAD mice, 3xTgAD/Polβ +/- mice exhibited impaired performance in a buried food test of olfaction. Polβ deficiency did not affect the proliferation of OB neural progenitor cells in the subventricular zone. However, numbers of newly generated neurons were reduced by approximately 25% in Polβ +/- and 3xTgAD mice, and by over 60% in the 3xTgAD/Polβ +/- mice compared to wild-type control mice. Analyses of DNA damage and apoptosis revealed significantly greater degeneration of OB neurons in 3xTgAD/Polβ +/- mice compared to 3xTgAD mice. Levels of amyloid β-peptide (Aβ) accumulation in the OB were similar in 3xTgAD and 3xTgAD/Polβ +/- mice, and cultured Polβ-deficient neurons exhibited increased vulnerability to Aβ-induced death. Olfactory deficit is an early sign in human AD, but the mechanism is not yet understood. Our findings in a new AD mouse model demonstrate that diminution of BER can endanger OB neurons, and suggest a mechanism underlying early olfactory impairment in AD. © 2016 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.

  15. Role of Centrifugal Projections to the Olfactory Bulb in Olfactory Processing

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    Kiselycznyk, Carly L.; Zhang, Steven; Linster, Christine

    2006-01-01

    While there is evidence that feedback projections from cortical and neuromodulatory structures to the olfactory bulb are crucial for maintaining the oscillatory dynamics of olfactory bulb processing, it is not clear how changes in dynamics are related to odor perception. Using electrical lesions of the olfactory peduncle, sparing output from the…

  16. Olfactory dysfunction, olfactory bulb pathology and urban air pollution

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    Calderón-Garcidueñas, Lilian; Franco-Lira, Maricela; Henríquez-Roldán, Carlos; Osnaya, Norma; González-Maciel, Angelica; Reynoso-Robles, Rafael; Villarreal-Calderon, Rafael; Herritt, Lou; Brooks, Diane; Keefe, Sheyla; Palacios-Moreno, Juan; Villarreal-Calderon, Rodolfo; Torres-Jardón, Ricardo; Medina-Cortina, Humberto; Delgado-Chávez, Ricardo; Aiello-Mora, Mario; Maronpot, Robert R.; Doty, Richard L

    2010-01-01

    Mexico City (MC) residents are exposed to severe air pollution and exhibit olfactory bulb inflammation. We compared the olfactory function of individuals living under conditions of extreme air pollution to that of controls from a relatively clean environment and explore associations between olfaction scores, apolipoprotein E (APOE) status, and pollution exposure. The olfactory bulbs (OBs) of 35 MC and 9 controls 20.8 ± 8.5 y were assessed by light and electron microscopy. The University of Pennsylvania Smell Identification Test (UPSIT) was administered to 62 MC / 25 controls 21.2 ±2.7 y. MC subjects had significantly lower UPSIT scores: 34.24 ± 0.42 versus controls 35.76 ± 0.40, p=0.03. Olfaction deficits were present in 35.5% MC and 12% of controls. MC APOE ε 4 carriers failed 2.4 ± 0.54 items in the 10-item smell identification scale from the UPSIT related to Alzheimer's disease, while APOE 2/3 and 3/3 subjects failed 1.36 ± 0.16 items, p = 0.01. MC residents exhibited OB endothelial hyperplasia, neuronal accumulation of particles (2/35), and immunoreactivity to beta amyloid βA42 (29/35) and/or α-synuclein (4/35) in neurons, glial cells and/or blood vessels. Ultrafine particles were present in OBs endothelial cytoplasm and basement membranes. Control OBs were unremarkable. Air pollution exposure is associated with olfactory dysfunction and OB pathology, APOE 4 may confer greater susceptibility to such abnormalities, and ultrafine particles could play a key role in the OB pathology. This study contributes to our understanding of the influences of air pollution on olfaction and its potential contribution to neurodegeneration. PMID:19297138

  17. MRI of the olfactory bulbs and sulci in human fetuses

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    Azoulay, Robin; Grabar, Sophie; Kalifa, Gabriel; Adamsbaum, Catherine; Fallet-Bianco, Catherine; Garel, Catherine

    2006-01-01

    There is limited knowledge of the MRI pattern of the development of fetal olfactory bulbs and sulci. To describe the MRI appearance of olfactory bulbs and sulci in normal in vivo fetuses according to gestational age. Olfactory bulbs and sulci were retrospectively assessed on brain MRI examinations of 88 normal fetuses between 24 and 39 weeks gestational age. Two reference centres were involved in the study and both used routine protocols that included axial and coronal T2- and T1-weighted sequences at 1.5 T. The results were compared both with the commonly used neuropathological data in the literature and with personal neuropathological data. Pearson's chi-squared test or Fisher's exact test were performed. One case of olfactory agenesis associated with CHARGE syndrome was identified. T2-weighted coronal sequences were the most sensitive for detecting olfactory bulbs and sulci. Olfactory sulci were significantly better detected from 30 weeks onwards (90.9-100%; P<0.001). MRI showed a posteroanterior development of these sulci. Olfactory bulbs were better detected from 30 to 34 weeks (80-90.9%; P<0.002). Comparison with neuropathological data confirmed the posteroanterior development of the sulci and showed an important delay in detection of the olfactory structures (bulbs and sulci). No difference was observed between the two centres involved. To date, fetal MRI can depict olfactory sulci from 30 weeks gestational age onwards and olfactory bulbs from 30 to 34 weeks gestational age. This preliminary reference standard is useful to assess the normality of the olfactory system and to diagnose olfactory agenesis. (orig.)

  18. Cholinergic innervation of the zebrafish olfactory bulb.

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    Edwards, Jeffrey G; Greig, Ann; Sakata, Yoko; Elkin, Dimitry; Michel, William C

    2007-10-20

    A number of fish species receive forebrain cholinergic input but two recent reports failed to find evidence of cholinergic cell bodies or fibers in the olfactory bulbs (OBs) of zebrafish. In the current study we sought to confirm these findings by examining the OBs of adult zebrafish for choline acetyltransferase (ChAT) immunoreactivity. We observed a diffuse network of varicose ChAT-positive fibers associated with the nervus terminalis ganglion innervating the mitral cell/glomerular layer (MC/GL). The highest density of these fibers occurred in the anterior region of the bulb. The cellular targets of this cholinergic input were identified by exposing isolated OBs to acetylcholine receptor (AChR) agonists in the presence of agmatine (AGB), a cationic probe that permeates some active ion channels. Nicotine (50 microM) significantly increased the activity-dependent labeling of mitral cells and juxtaglomerular cells but not of tyrosine hydroxlase-positive dopaminergic neurons (TH(+) cells) compared to control preparations. The nAChR antagonist mecamylamine, an alpha7-nAChR subunit-specific antagonist, calcium-free artificial cerebrospinal fluid, or a cocktail of ionotropic glutamate receptor (iGluR) antagonists each blocked nicotine-stimulated labeling, suggesting that AGB does not enter the labeled neurons through activated nAChRs but rather through activated iGluRs following ACh-stimulated glutamate release. Deafferentation of OBs did not eliminate nicotine-stimulated labeling, suggesting that cholinergic input is primarily acting on bulbar neurons. These findings confirm the presence of a functioning cholinergic system in the zebrafish OB.

  19. Voltage-Dependent Intrinsic Bursting in Olfactory Bulb Golgi Cells

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    Pressler, R. Todd; Rozman, Peter A.; Strowbridge, Ben W.

    2013-01-01

    In the mammalian olfactory bulb (OB), local synaptic circuits modulate the evolving pattern of activity in mitral and tufted cells following olfactory sensory stimulation. GABAergic granule cells, the most numerous interneuron subtype in this brain region, have been extensively studied. However, classic studies using Golgi staining methods…

  20. A circadian clock in the olfactory bulb anticipates feeding during food anticipatory activity.

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    Nolasco, Nahum; Juárez, Claudia; Morgado, Elvira; Meza, Enrique; Caba, Mario

    2012-01-01

    Rabbit pups ingest food, in this case milk, once a day with circadian periodicity and are a natural model of food anticipatory activity. During nursing, several sensory systems receive information about properties of the food, one of them being the olfactory system, which has received little attention in relation to synchronization by food. In addition, the olfactory bulb has a circadian pacemaker that exhibits rhythms independently of the suprachiasmatic nucleus, but the biological functions of these rhythms are largely unknown. In the present contribution, we hypothesized that circadian suckling of milk synchronizes rhythms in the olfactory bulb. To this aim we explored by immunohistochemistry, rhythms of FOS and PER1 proteins, as indicators of activation and reporter of oscillations, respectively, through a complete 24-h cycle in periglomerular, mitral and granular cell layers of both the main and the accessory olfactory bulb. Subjects were 7-day-old rabbit pups scheduled to nurse during the night (02:00 h) or day (10:00 h), and also fasted subjects, to explore the possible persistence of oscillations. In the three layers of the main olfactory bulb, FOS was high at time of nursing, then further increased 1.5 h afterward, and then decreased to increase again in advance of the next nursing bout. This pattern persisted, without the postprandial increase, in fasted subjects with a shift in subjects nursed at 02:00. PER1 was increased 2-8 h after nursing and this increase persisted in most cell layers, with a shift, in fasted subjects. In the accessory olfactory bulb we only observed a consistent pattern of FOS expression in the mitral cell layer of nursed subjects, similar to that of the main olfactory bulb. We conclude that the main olfactory bulb is synchronized during milk ingestion, but during fasting its oscillations perhaps are modulated by the suprachiasmatic nucleus, as proposed for rodents.

  1. A circadian clock in the olfactory bulb anticipates feeding during food anticipatory activity.

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    Nahum Nolasco

    Full Text Available Rabbit pups ingest food, in this case milk, once a day with circadian periodicity and are a natural model of food anticipatory activity. During nursing, several sensory systems receive information about properties of the food, one of them being the olfactory system, which has received little attention in relation to synchronization by food. In addition, the olfactory bulb has a circadian pacemaker that exhibits rhythms independently of the suprachiasmatic nucleus, but the biological functions of these rhythms are largely unknown. In the present contribution, we hypothesized that circadian suckling of milk synchronizes rhythms in the olfactory bulb. To this aim we explored by immunohistochemistry, rhythms of FOS and PER1 proteins, as indicators of activation and reporter of oscillations, respectively, through a complete 24-h cycle in periglomerular, mitral and granular cell layers of both the main and the accessory olfactory bulb. Subjects were 7-day-old rabbit pups scheduled to nurse during the night (02:00 h or day (10:00 h, and also fasted subjects, to explore the possible persistence of oscillations. In the three layers of the main olfactory bulb, FOS was high at time of nursing, then further increased 1.5 h afterward, and then decreased to increase again in advance of the next nursing bout. This pattern persisted, without the postprandial increase, in fasted subjects with a shift in subjects nursed at 02:00. PER1 was increased 2-8 h after nursing and this increase persisted in most cell layers, with a shift, in fasted subjects. In the accessory olfactory bulb we only observed a consistent pattern of FOS expression in the mitral cell layer of nursed subjects, similar to that of the main olfactory bulb. We conclude that the main olfactory bulb is synchronized during milk ingestion, but during fasting its oscillations perhaps are modulated by the suprachiasmatic nucleus, as proposed for rodents.

  2. Newborn Interneurons in the Accessory Olfactory Bulb Promote Mate Recognition in Female Mice

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    Livio eOboti

    2011-09-01

    Full Text Available In the olfactory bulb of adult rodents, local interneurons are constantly replaced by immature precursors derived from the subventricular zone. Whether any olfactory sensory process specifically relies on this cell renewal remains largely unclear. By using the well-known model of mating-induced imprinting, we demonstrate that this olfactory memory formation critically depends on the presence of newborn granule neurons in the accessory olfactory bulb. Accordingly, we show that, in adult female mice, exposure to male pheromones increases the number of new granule cells surviving in the accessory olfactory bulb. This neuronal addition depends on the detection of sensory cues by the vomeronasal organ and requires centrifugal feedback activity from the amygdala. The stimuli affecting neuronal survival are contained in the low molecular weight fraction of urine and are implied in pheromonal recognition during mating. By chemical depletion of newly generated bulbar interneurons, we show a direct role of renewed granule cells in the accessory olfactory bulb in preventing pregnancy block by mating male odours. Taken together, our results indicate that adult neurogenesis is essential for specific brain functions such as persistent odour learning and mate recognition.

  3. Specific olfactory receptor populations projecting to identified glomeruli in the rat olfactory bulb.

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    Jastreboff, P J; Pedersen, P E; Greer, C A; Stewart, W B; Kauer, J S; Benson, T E; Shepherd, G M

    1984-08-01

    A critical gap exists in our knowledge of the topographical relationship between the olfactory epithelium and olfactory bulb. The present report describes the application to this problem of a method involving horseradish peroxidase conjugated to wheat germ agglutinin. This material was iontophoretically delivered to circumscribed glomeruli in the olfactory bulb and the characteristics and distribution of retrogradely labeled receptor cells were assessed. After discrete injections into small glomerular groups in the caudomedial bulb, topographically defined populations of receptor cells were labeled. Labeled receptor cell somata appeared at several levels within the epithelium. The receptor cell apical dendrites followed a tight helical course towards the surface of the epithelium. The data thus far demonstrate that functional units within the olfactory system may include not only glomeruli as previously suggested but, in addition, a corresponding matrix of receptor cells possessing functional and topographical specificity.

  4. Stimulus-response functions of single avian olfactory bulb neurones.

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    McKeegan, Dorothy E F; Demmers, Theodorus G M; Wathes, Christopher M; Jones, R Bryan; Gentle, Michael J

    2002-10-25

    This study investigated olfactory processing in a functional context by examining the responses of single avian olfactory bulb neurones to two biologically important gases over relevant concentration ranges. Recordings of extracellular spike activity were made from 80 single units in the left olfactory bulb of 11 anaesthetised, freely breathing adult hens (Gallus domesticus). The units were spontaneously active, exhibiting widely variable firing rates (0.07-47.28 spikes/s) and variable temporal firing patterns. Single units were tested for their response to an ascending concentration series of either ammonia (2.5-100 ppm) or hydrogen sulphide (1-50 ppm), delivered directly to the olfactory epithelium. Stimulation with a calibrated gas delivery system resulted in modification of spontaneous activity causing either inhibition (47% of units) or excitation (53%) of firing. For ammonia, 20 of the 35 units tested exhibited a response, while for hydrogen sulphide, 25 of the 45 units tested were responsive. Approximate response thresholds for ammonia (median threshold 3.75 ppm (range 2.5-60 ppm, n=20)) and hydrogen sulphide (median threshold 1 ppm (range 1-10 ppm, n=25)) were determined with most units exhibiting thresholds near the lower end of these ranges. Stimulus response curves were constructed for 23 units; 16 (the most complete) were subjected to a linear regression analysis to determine whether they were best fitted by a linear, log or power function. No single function provided the best fit for all the curves (seven were linear, eight were log, one was power). These findings show that avian units respond to changes in stimulus concentration in a manner generally consistent with reported responses in mammalian olfactory bulb neurones. However, this study illustrates a level of fine-tuning to small step changes in concentration (<5 ppm) not previously demonstrated in vertebrate single olfactory bulb neurones.

  5. Consolidation of an olfactory memory trace in the olfactory bulb is required for learning-induced survival of adult-born neurons and long-term memory.

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    Florence Kermen

    Full Text Available BACKGROUND: It has recently been proposed that adult-born neurons in the olfactory bulb, whose survival is modulated by learning, support long-term olfactory memory. However, the mechanism used to select which adult-born neurons following learning will participate in the long-term retention of olfactory information is unknown. We addressed this question by investigating the effect of bulbar consolidation of olfactory learning on memory and neurogenesis. METHODOLOGY/PRINCIPAL FINDINGS: Initially, we used a behavioral ecological approach using adult mice to assess the impact of consolidation on neurogenesis. Using learning paradigms in which consolidation time was varied, we showed that a spaced (across days, but not a massed (within day, learning paradigm increased survival of adult-born neurons and allowed long-term retention of the task. Subsequently, we used a pharmacological approach to block consolidation in the olfactory bulb, consisting in intrabulbar infusion of the protein synthesis inhibitor anisomycin, and found impaired learning and no increase in neurogenesis, while basic olfactory processing and the basal rate of adult-born neuron survival remained unaffected. Taken together these data indicate that survival of adult-born neurons during learning depends on consolidation processes taking place in the olfactory bulb. CONCLUSION/SIGNIFICANCE: We can thus propose a model in which consolidation processes in the olfactory bulb determine both survival of adult-born neurons and long-term olfactory memory. The finding that adult-born neuron survival during olfactory learning is governed by consolidation in the olfactory bulb strongly argues in favor of a role for bulbar adult-born neurons in supporting olfactory memory.

  6. Consolidation of an olfactory memory trace in the olfactory bulb is required for learning-induced survival of adult-born neurons and long-term memory.

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    Kermen, Florence; Sultan, Sébastien; Sacquet, Joëlle; Mandairon, Nathalie; Didier, Anne

    2010-08-13

    It has recently been proposed that adult-born neurons in the olfactory bulb, whose survival is modulated by learning, support long-term olfactory memory. However, the mechanism used to select which adult-born neurons following learning will participate in the long-term retention of olfactory information is unknown. We addressed this question by investigating the effect of bulbar consolidation of olfactory learning on memory and neurogenesis. Initially, we used a behavioral ecological approach using adult mice to assess the impact of consolidation on neurogenesis. Using learning paradigms in which consolidation time was varied, we showed that a spaced (across days), but not a massed (within day), learning paradigm increased survival of adult-born neurons and allowed long-term retention of the task. Subsequently, we used a pharmacological approach to block consolidation in the olfactory bulb, consisting in intrabulbar infusion of the protein synthesis inhibitor anisomycin, and found impaired learning and no increase in neurogenesis, while basic olfactory processing and the basal rate of adult-born neuron survival remained unaffected. Taken together these data indicate that survival of adult-born neurons during learning depends on consolidation processes taking place in the olfactory bulb. We can thus propose a model in which consolidation processes in the olfactory bulb determine both survival of adult-born neurons and long-term olfactory memory. The finding that adult-born neuron survival during olfactory learning is governed by consolidation in the olfactory bulb strongly argues in favor of a role for bulbar adult-born neurons in supporting olfactory memory.

  7. Inducible Activation of ERK5 MAP Kinase Enhances Adult Neurogenesis in the Olfactory Bulb and Improves Olfactory Function

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    Wang, Wenbin; Lu, Song; Li, Tan; Pan, Yung-Wei; Zou, Junhui; Abel, Glen M.; Xu, Lihong; Storm, Daniel R.

    2015-01-01

    Recent discoveries have suggested that adult neurogenesis in the subventricular zone (SVZ) and olfactory bulb (OB) may be required for at least some forms of olfactory behavior in mice. However, it is unclear whether conditional and selective enhancement of adult neurogenesis by genetic approaches is sufficient to improve olfactory function under physiological conditions or after injury. Furthermore, specific signaling mechanisms regulating adult neurogenesis in the SVZ/OB are not fully defined. We previously reported that ERK5, a MAP kinase selectively expressed in the neurogenic regions of the adult brain, plays a critical role in adult neurogenesis in the SVZ/OB. Using a site-specific knock-in mouse model, we report here that inducible and targeted activation of the endogenous ERK5 in adult neural stem/progenitor cells enhances adult neurogenesis in the OB by increasing cell survival and neuronal differentiation. This conditional ERK5 activation also improves short-term olfactory memory and odor-cued associative olfactory learning under normal physiological conditions. Furthermore, these mice show enhanced recovery of olfactory function and have more adult-born neurons after a zinc sulfate-induced lesion of the main olfactory epithelium. We conclude that ERK5 MAP kinase is an important endogenous signaling pathway regulating adult neurogenesis in the SVZ/OB, and that conditional activation of endogenous ERK5 is sufficient to enhance adult neurogenesis in the OB thereby improving olfactory function both under normal conditions and after injury. PMID:25995470

  8. Accumulation of [35S]taurine in peripheral layers of the olfactory bulb

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    Quinn, M.R.; Wysocki, C.J.; Sturman, J.A.; Wen, G.Y.

    1981-01-01

    Accumulation of [ 35 S]taurine in the laminae of the olfactory bulb of the adult cat, rat, mouse and rabbit was examined autoradiographically. [ 35 S]Taurine was administered either i.p. or i.v. and olfactory bulbs were excised 24 h post-injection. High concentrations of [ 35 S]taurine were restricted to the olfactory nerve and glomerular layers of the olfactory bulb in all species examined. Olfactory neurons are continuously renewed and the results obtained suggest that taurine may have an important role in olfactory receptor axons. (Auth.)

  9. Learning-dependent neurogenesis in the olfactory bulb determines long-term olfactory memory.

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    Sultan, S; Mandairon, N; Kermen, F; Garcia, S; Sacquet, J; Didier, A

    2010-07-01

    Inhibitory interneurons of the olfactory bulb are subjected to permanent adult neurogenesis. Their number is modulated by learning, suggesting that they could play a role in plastic changes of the bulbar network associated with olfactory memory. Adult male C57BL/6 mice were trained in an associative olfactory task, and we analyzed long-term retention of the task 5, 30, and 90 d post-training. In parallel, we assessed the fate of these newborn cells, mapped their distribution in the olfactory bulb and measured their functional implication using the immediate early gene Zif268. In a second set of experiments, we pharmacologically modulated glutamatergic transmission and using the same behavioral task assessed the consequences on memory retention and neurogenesis. Finally, by local infusion of an antimitotic drug, we selectively blocked neurogenesis during acquisition of the task and looked at the effects on memory retention. First we demonstrated that retrieval of an associative olfactory task recruits the newborn neurons in odor-specific areas of the olfactory bulb selected to survive during acquisition of the task and that it does this in a manner that depends on the strength of learning. We then demonstrated that acquisition is not dependent on neurogenesis if long-term retention of the task is abolished by blocking neurogenesis. Adult-born neurons are thus involved in changes in the neural representation of an odor; this underlies long-term olfactory memory as the strength of learning is linked to the duration of this memory. Neurogenesis thus plays a crucial role in long-term olfactory memory.

  10. Olfactory aversive conditioning alters olfactory bulb mitral/tufted cell glomerular odor responses

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    Max L Fletcher

    2012-03-01

    Full Text Available The anatomical organization of receptor neuron input into the olfactory bulb (OB allows odor information to be transformed into an odorant-specific spatial map of mitral/tufted cell glomerular activity at the upper level of the olfactory bulb. In other sensory systems, neuronal representations of stimuli can be reorganized or enhanced following learning. While the mammalian OB has been shown to undergo experience-dependent plasticity at the glomerular level, it is still unclear if similar representational change occurs within mitral/tufted cell glomerular odor representations following learning. To address this, odorant-evoked glomerular activity patterns were imaged in mice expressing a GFP-based calcium indicator (GCaMP2 in OB mitral/tufted cells. Glomerular odor responses were imaged before and after olfactory associative conditioning to aversive foot shock. Following conditioning, we found no overall reorganization of the glomerular representation. Training, however, did significantly alter the amplitudes of individual glomeruli within the representation in mice in which the odor was presented together with foot shock. Further, the specific pairing of foot shock with odor presentations lead to increased responses primarily in initially weakly activated glomeruli. Overall, these results suggest that associative conditioning can enhance the initial representation of odors within the olfactory bulb by enhancing responses to the learned odor in some glomeruli.

  11. Serotonin increases synaptic activity in olfactory bulb glomeruli.

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    Brill, Julia; Shao, Zuoyi; Puche, Adam C; Wachowiak, Matt; Shipley, Michael T

    2016-03-01

    Serotoninergic fibers densely innervate olfactory bulb glomeruli, the first sites of synaptic integration in the olfactory system. Acting through 5HT2A receptors, serotonin (5HT) directly excites external tufted cells (ETCs), key excitatory glomerular neurons, and depolarizes some mitral cells (MCs), the olfactory bulb's main output neurons. We further investigated 5HT action on MCs and determined its effects on the two major classes of glomerular interneurons: GABAergic/dopaminergic short axon cells (SACs) and GABAergic periglomerular cells (PGCs). In SACs, 5HT evoked a depolarizing current mediated by 5HT2C receptors but did not significantly impact spike rate. 5HT had no measurable direct effect in PGCs. Serotonin increased spontaneous excitatory and inhibitory postsynaptic currents (sEPSCs and sIPSCs) in PGCs and SACs. Increased sEPSCs were mediated by 5HT2A receptors, suggesting that they are primarily due to enhanced excitatory drive from ETCs. Increased sIPSCs resulted from elevated excitatory drive onto GABAergic interneurons and augmented GABA release from SACs. Serotonin-mediated GABA release from SACs was action potential independent and significantly increased miniature IPSC frequency in glomerular neurons. When focally applied to a glomerulus, 5HT increased MC spontaneous firing greater than twofold but did not increase olfactory nerve-evoked responses. Taken together, 5HT modulates glomerular network activity in several ways: 1) it increases ETC-mediated feed-forward excitation onto MCs, SACs, and PGCs; 2) it increases inhibition of glomerular interneurons; 3) it directly triggers action potential-independent GABA release from SACs; and 4) these network actions increase spontaneous MC firing without enhancing responses to suprathreshold sensory input. This may enhance MC sensitivity while maintaining dynamic range. Copyright © 2016 the American Physiological Society.

  12. Olfactory disfunction and its relation olfactory bulb volume in Parkinson's disease.

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    Altinayar, S; Oner, S; Can, S; Kizilay, A; Kamisli, S; Sarac, K

    2014-01-01

    Olfactory dysfunction is the most frequently seen non-motor symptom of Idiopathic Parkinson's disease (IPD). The aim of this study is to analyze selective olfactory dysfunction, and olfactory bulb volume (OBV) in subtypes of IPD, and compare them with those of the healthy controls. Our study included 41 patients with IPD and age and gender matched 19 healthy controls. IPD patients were either tremor dominant (65.9%; TDPD) or non-tremor dominant (34.1%; NTDPD) type. All patients underwent neurological, ear, nose, and throat examinations, and orthonasal olfaction testing. Magnetic resonance imaging (MRI) technique was used to measure the volume of the olfactory bulb. A significant decrease in olfactory identification scores was found in the patient group. The patients had difficulty in discriminating between odors of mothballs, chocolate, Turkish coffee and soap. OBV did not differ between the patient, and the control groups. In the TDPD group, odor identification ability was decreased when compared to the control group. However, odor test results of NTDPD, control and TDPD groups were similar. OBV estimates of the TDPD group were not different from those of the control group, while in the NTDPD group OBVs were found to be decreased. In all patients with Parkinson's disease OBV values did not vary with age of the patients, duration of the disease, age at onset of the disease, and Unified Parkinson's Disease Rating Scale motor scores (UPDRS-m). Olfactory function is a complex process involving olfactory, and cortical structures as well. In Idiopathic Parkinson's disease, changes in OBV do not seem to be directly related to olfactory dysfunction.

  13. Odor memory stability after reinnervation of the olfactory bulb.

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    Eduardo Blanco-Hernández

    Full Text Available The olfactory system, particularly the olfactory epithelium, presents a unique opportunity to study the regenerative capabilities of the brain, because of its ability to recover after damage. In this study, we ablated olfactory sensory neurons with methimazole and followed the anatomical and functional recovery of circuits expressing genetic markers for I7 and M72 receptors (M72-IRES-tau-LacZ and I7-IRES-tau-GFP. Our results show that 45 days after methimazole-induced lesion, axonal projections to the bulb of M72 and I7 populations are largely reestablished. Furthermore, regenerated glomeruli are re-formed within the same areas as those of control, unexposed mice. This anatomical regeneration correlates with functional recovery of a previously learned odorant-discrimination task, dependent on the cognate ligands for M72 and I7. Following regeneration, mice also recover innate responsiveness to TMT and urine. Our findings show that regeneration of neuronal circuits in the olfactory system can be achieved with remarkable precision and underscore the importance of glomerular organization to evoke memory traces stored in the brain.

  14. Photoperiod mediated changes in olfactory bulb neurogenesis and olfactory behavior in male white-footed mice (Peromyscus leucopus.

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    James C Walton

    Full Text Available Brain plasticity, in relation to new adult mammalian neurons generated in the subgranular zone of the hippocampus, has been well described. However, the functional outcome of new adult olfactory neurons born in the subventricular zone of the lateral ventricles is not clearly defined, as manipulating neurogenesis through various methods has given inconsistent and conflicting results in lab mice. Several small rodent species, including Peromyscus leucopus, display seasonal (photoperiodic brain plasticity in brain volume, hippocampal function, and hippocampus-dependent behaviors; plasticity in the olfactory system of photoperiodic rodents remains largely uninvestigated. We exposed adult male P. leucopus to long day lengths (LD and short day lengths (SD for 10 to 15 weeks and then examined olfactory bulb cell proliferation and survival using the thymidine analog BrdU, olfactory bulb granule cell morphology using Golgi-Cox staining, and behavioral investigation of same-sex conspecific urine. SD mice did not differ from LD counterparts in granular cell morphology of the dendrites or in dendritic spine density. Although there were no differences due to photoperiod in habituation to water odor, SD mice rapidly habituated to male urine, whereas LD mice did not. In addition, short day induced changes in olfactory behavior were associated with increased neurogenesis in the caudal plexiform and granule cell layers of the olfactory bulb, an area known to preferentially respond to water-soluble odorants. Taken together, these data demonstrate that photoperiod, without altering olfactory bulb neuronal morphology, alters olfactory bulb neurogenesis and olfactory behavior in Peromyscus leucopus.

  15. Neuronal Subtype Generation During Postnatal Olfactory Bulb Neurogenesis.

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    Angelova, Alexandra; Tiveron, Marie-Catherine; Cremer, Harold; Beclin, Christophe

    2018-01-01

    In the perinatal and adult forebrain, regionalized neural stem cells lining the ventricular walls produce different types of olfactory bulb interneurons. Although these postnatal stem cells are lineage related to their embryonic counterparts that produce, for example, cortical, septal, and striatal neurons, their output at the level of neuronal phenotype changes dramatically. Tiveron et al. investigated the molecular determinants underlying stem cell regionalization and the gene expression changes inducing the shift from embryonic to adult neuron production. High-resolution gene expression analyses of different lineages revealed that the zinc finger proteins, Zic1 and Zic2, are postnatally induced in the dorsal olfactory bulb neuron lineage. Functional studies demonstrated that these factors confer a GABAergic and calretinin-positive phenotype to neural stem cells while repressing dopaminergic fate. Based on these findings, we discuss the molecular mechanisms that allow acquisition of new traits during the transition from embryonic to adult neurogenesis. We focus on the involvement of epigenetic marks and emphasize why the identification of master transcription factors, that instruct the fate of postnatally generated neurons, can help in deciphering the mechanisms driving fate transition from embryonic to adult neuron production.

  16. Neuronal Subtype Generation During Postnatal Olfactory Bulb Neurogenesis

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    Alexandra Angelova

    2018-02-01

    Full Text Available In the perinatal and adult forebrain, regionalized neural stem cells lining the ventricular walls produce different types of olfactory bulb interneurons. Although these postnatal stem cells are lineage related to their embryonic counterparts that produce, for example, cortical, septal, and striatal neurons, their output at the level of neuronal phenotype changes dramatically. Tiveron et al. investigated the molecular determinants underlying stem cell regionalization and the gene expression changes inducing the shift from embryonic to adult neuron production. High-resolution gene expression analyses of different lineages revealed that the zinc finger proteins, Zic1 and Zic2, are postnatally induced in the dorsal olfactory bulb neuron lineage. Functional studies demonstrated that these factors confer a GABAergic and calretinin-positive phenotype to neural stem cells while repressing dopaminergic fate. Based on these findings, we discuss the molecular mechanisms that allow acquisition of new traits during the transition from embryonic to adult neurogenesis. We focus on the involvement of epigenetic marks and emphasize why the identification of master transcription factors, that instruct the fate of postnatally generated neurons, can help in deciphering the mechanisms driving fate transition from embryonic to adult neuron production.

  17. Inducible activation of ERK5 MAP kinase enhances adult neurogenesis in the olfactory bulb and improves olfactory function.

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    Wang, Wenbin; Lu, Song; Li, Tan; Pan, Yung-Wei; Zou, Junhui; Abel, Glen M; Xu, Lihong; Storm, Daniel R; Xia, Zhengui

    2015-05-20

    Recent discoveries have suggested that adult neurogenesis in the subventricular zone (SVZ) and olfactory bulb (OB) may be required for at least some forms of olfactory behavior in mice. However, it is unclear whether conditional and selective enhancement of adult neurogenesis by genetic approaches is sufficient to improve olfactory function under physiological conditions or after injury. Furthermore, specific signaling mechanisms regulating adult neurogenesis in the SVZ/OB are not fully defined. We previously reported that ERK5, a MAP kinase selectively expressed in the neurogenic regions of the adult brain, plays a critical role in adult neurogenesis in the SVZ/OB. Using a site-specific knock-in mouse model, we report here that inducible and targeted activation of the endogenous ERK5 in adult neural stem/progenitor cells enhances adult neurogenesis in the OB by increasing cell survival and neuronal differentiation. This conditional ERK5 activation also improves short-term olfactory memory and odor-cued associative olfactory learning under normal physiological conditions. Furthermore, these mice show enhanced recovery of olfactory function and have more adult-born neurons after a zinc sulfate-induced lesion of the main olfactory epithelium. We conclude that ERK5 MAP kinase is an important endogenous signaling pathway regulating adult neurogenesis in the SVZ/OB, and that conditional activation of endogenous ERK5 is sufficient to enhance adult neurogenesis in the OB thereby improving olfactory function both under normal conditions and after injury. Copyright © 2015 the authors 0270-6474/15/357833-17$15.00/0.

  18. Sparse distributed representation of odors in a large-scale olfactory bulb circuit.

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    Yuguo Yu

    Full Text Available In the olfactory bulb, lateral inhibition mediated by granule cells has been suggested to modulate the timing of mitral cell firing, thereby shaping the representation of input odorants. Current experimental techniques, however, do not enable a clear study of how the mitral-granule cell network sculpts odor inputs to represent odor information spatially and temporally. To address this critical step in the neural basis of odor recognition, we built a biophysical network model of mitral and granule cells, corresponding to 1/100th of the real system in the rat, and used direct experimental imaging data of glomeruli activated by various odors. The model allows the systematic investigation and generation of testable hypotheses of the functional mechanisms underlying odor representation in the olfactory bulb circuit. Specifically, we demonstrate that lateral inhibition emerges within the olfactory bulb network through recurrent dendrodendritic synapses when constrained by a range of balanced excitatory and inhibitory conductances. We find that the spatio-temporal dynamics of lateral inhibition plays a critical role in building the glomerular-related cell clusters observed in experiments, through the modulation of synaptic weights during odor training. Lateral inhibition also mediates the development of sparse and synchronized spiking patterns of mitral cells related to odor inputs within the network, with the frequency of these synchronized spiking patterns also modulated by the sniff cycle.

  19. Ulex europaeus I and glycine max bind to the human olfactory bulb.

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    Nagao, M; Oka, N; Kamo, H; Akiguchi, I; Kimura, J

    1993-12-24

    The distribution of binding sites for the fucose-selective lectin Ulex europaeus I and the terminal N-acetylgalactosamine-selective lectin glycine max in the human olfactory bulb were studied. These lectins bound to primary olfactory axons in the olfactory nerve layer and the glomerular layer. They also bound to fibers located in the deeper layers such as the external plexiform layer and the granular layer. Furthermore they projected to the olfactory stalk but not in the cerebrum. The deeper projections of the lectin binding fibers may affect the function of the olfactory bulb in humans.

  20. Retro- and orthonasal olfactory function in relation to olfactory bulb volume in patients with hypogonadotrophic hypogonadism.

    Science.gov (United States)

    Salihoglu, Murat; Kurt, Onuralp; Ay, Seyid Ahmet; Baskoy, Kamil; Altundag, Aytug; Saglam, Muzaffer; Deniz, Ferhat; Tekeli, Hakan; Yonem, Arif; Hummel, Thomas

    2017-08-24

    Idiopathic hypogonadotrophic hypogonadism (IHH) with an olfactory deficit is defined as Kallmann syndrome (KS) and is distinct from normosmic IHH. Because olfactory perception not only consists of orthonasally gained impressions but also involves retronasal olfactory function, in this study we decided to comprehensively evaluate both retronasal and orthonasal olfaction in patients with IHH. This case-control study included 31 controls and 45 IHH patients. All participants whose olfactory and taste functions were evaluated with orthonasal olfaction (discrimination, identification and threshold), retronasal olfaction, taste function and olfactory bulb volume (OBV) measurement. The patients were separated into three groups according to orthonasal olfaction: anosmic IHH (aIHH), hyposmic IHH (hIHH) and normosmic IHH (nIHH). Discrimination, identification and threshold scores of patients with KS were significantly lower than controls. Threshold scores of patients with nIHH were significantly lower than those of controls, but discrimination and identification scores were not significantly different. Retronasal olfaction was reduced only in the aIHH group compared to controls. Identification of bitter, sweet, sour, and salty tastes was not significantly different when compared between the anosmic, hyposmic, and normosmic IHH groups and controls. OBV was lower bilaterally in all patient groups when compared with controls. The OBV of both sides was found to be significantly correlated with TDI scores in IHH patients. 1) There were no significant differences in gustatory function between controls and IHH patients; 2) retronasal olfaction was reduced only in anosmic patients but not in orthonasally hyposmic participants, possibly indicating presence of effective compensatory mechanisms; 3) olfactory bulb volumes were highly correlated with olfaction scores in the HH group. The current results indicate a continuum from anosmia to normosmia in IHH patients. Copyright © 2017

  1. Effect of basal forebrain stimulation on extracellular acetylcholine release and blood flow in the olfactory bulb.

    Science.gov (United States)

    Uchida, Sae; Kagitani, Fusako

    2017-05-12

    The olfactory bulb receives cholinergic basal forebrain input, as does the neocortex; however, the in vivo physiological functions regarding the release of extracellular acetylcholine and regulation of regional blood flow in the olfactory bulb are unclear. We used in vivo microdialysis to measure the extracellular acetylcholine levels in the olfactory bulb of urethane-anesthetized rats. Focal chemical stimulation by microinjection of L-glutamate into the horizontal limb of the diagonal band of Broca (HDB) in the basal forebrain, which is the main source of cholinergic input to the olfactory bulb, increased extracellular acetylcholine release in the ipsilateral olfactory bulb. When the regional cerebral blood flow was measured using laser speckle contrast imaging, the focal chemical stimulation of the HDB did not significantly alter the blood flow in the olfactory bulb, while increases were observed in the neocortex. Our results suggest a functional difference between the olfactory bulb and neocortex regarding cerebral blood flow regulation through the release of acetylcholine by cholinergic basal forebrain input.

  2. Olfactory bulb proteins linked to olfactory memory in C57BL/6J mice.

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    Li, Lin; Mauric, Veronika; Zheng, Jun-Fang; Kang, Sung Ung; Patil, Sudarshan; Höger, Harald; Lubec, Gert

    2010-08-01

    Information on systematic analysis of olfactory memory-related proteins is poor. In this study, the odor discrimination task to investigate olfactory recognition memory of adult male C57BL/6J mice was used. Subsequently, olfactory bulbs (OBs) were taken, proteins extracted, and run on two-dimensional gel electrophoresis with in-gel-protein digestion, followed by mass spectrometry and quantification of differentially expressed proteins. Dual specificity mitogen-activated protein kinase kinase 1 (MEK1), dihydropyrimidinase-related protein 1 (DRP1), and fascin are related with Lemon odor memory. Microtubule-associated protein RP/EB family member 3 is related to Rose odor memory. Hypoxanthine-guanine phosphoribosyltransferase is related with both Lemon and Rose odors memory. MEK1 and DRP1 levels were increased, while microtubule-associated protein RP/EB family member 3, fascin and hypoxanthine-guanine phosphoribosyltransferase levels were decreased during olfactory memory. In summary, neurogenesis, signal transduction, cytoskeleton, and nucleotide metabolism are involved in olfactory memory formation and storage of C57BL/6J mice.

  3. Size matters - The olfactory bulb as a marker for depression.

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    Rottstaedt, F; Weidner, K; Strauß, T; Schellong, J; Kitzler, H; Wolff-Stephan, S; Hummel, T; Croy, I

    2018-03-15

    Major Depression is mainly related to structural and functional alterations in brain networks involving limbic and prefrontal regions. Reduced olfactory sensitivity in depression is associated with reduced olfactory bulb (OB) volume. We determined if the OB volume reduction is a specific biomarker for depression and whether its diagnostic accuracy allows its use as a valid biomarker to support its diagnosis. 84 in-patients with mixed mental disorders and 51 age-matched healthy controls underwent structural MR imaging with a spin-echo T2-wheighted sequence. Individual OB volume was calculated manually (interrater-reliability = .81, p < .001) and compared between groups. Multiple regression analysis with OB volume as dependent variable and Receiver Operator Characteristic analysis to obtain its diagnostic accuracy for depression were ruled out. Patients exhibited a 13.5% reduced OB volume. Multiple regression analysis showed that the OB volume variation was best explained by depression (β = -.19), sex (β = -.31) and age (β = -.29), but not by any other mental disorder. OB volume attained a diagnostic accuracy of 68.1% for depression. The patient group mainly contained highly comorbid patients with mostly internalizing disorders which limits the generalisability of the results of the regression analysis. The OB may serve as a marker for depression. We assume that reduced neural olfactory input to subsequent limbic and salience processing structures moderates this relation. However, the OB was in an inferior position compared to conventional questionnaires for diagnosis of depression. Combination with further structural or functional measurements is suggested. Copyright © 2018 Elsevier B.V. All rights reserved.

  4. Olfactory bulb glomerular NMDA receptors mediate olfactory nerve potentiation and odor preference learning in the neonate rat.

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    Rebecca Lethbridge

    Full Text Available Rat pup odor preference learning follows pairing of bulbar beta-adrenoceptor activation with olfactory input. We hypothesize that NMDA receptor (NMDAR-mediated olfactory input to mitral cells is enhanced during training, such that increased calcium facilitates and shapes the critical cAMP pattern. Here, we demonstrate, in vitro, that olfactory nerve stimulation, at sniffing frequencies, paired with beta-adrenoceptor activation, potentiates olfactory nerve-evoked mitral cell firing. This potentiation is blocked by a NMDAR antagonist and by increased inhibition. Glomerular disinhibition also induces NMDAR-sensitive potentiation. In vivo, in parallel, behavioral learning is prevented by glomerular infusion of an NMDAR antagonist or a GABA(A receptor agonist. A glomerular GABA(A receptor antagonist paired with odor can induce NMDAR-dependent learning. The NMDA GluN1 subunit is phosphorylated in odor-specific glomeruli within 5 min of training suggesting early activation, and enhanced calcium entry, during acquisition. The GluN1 subunit is down-regulated 3 h after learning; and at 24 h post-training the GluN2B subunit is down-regulated. These events may assist memory stability. Ex vivo experiments using bulbs from trained rat pups reveal an increase in the AMPA/NMDA EPSC ratio post-training, consistent with an increase in AMPA receptor insertion and/or the decrease in NMDAR subunits. These results support a model of a cAMP/NMDA interaction in generating rat pup odor preference learning.

  5. Blocking muscarinic receptors in the olfactory bulb impairs performance on an olfactory short term memory task

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    Sasha eDevore

    2012-09-01

    Full Text Available Cholinergic inputs to cortical processing networks have long been associated with attentional and top-down processing. Experimental and theoretical studies suggest that cholinergic inputs to the main olfactory bulb (OB can modulate both neural and behavioral odor discrimination. Previous experiments from our laboratory and others demonstrate that blockade of nicotinic receptors directly impairs olfactory discrimination, whereas blockade of muscarinic receptors only measurably impairs olfactory perception when task demands are made more challenging, such as when very low-concentration odors are used or rats are required to maintain sensory memory over long durations. To further investigate the role of muscarinic signaling in the OB, we developed an olfactory delayed match-to-sample task using a digging-based behavioral paradigm. We find that rats are able to maintain robust short-term odor memory for tens to hundreds of seconds. To investigate the role of muscarinic signaling in task performance, we bilaterally infused scopolamine into the OB. We find that high dosages of scopolamine (38 mM impair performance on the task across all delays tested, including the baseline condition with no delay, whereas lower dosages (7.6 mM and 22.8 mM had no measureable effects. These results indicate that general execution of the match-to-sample task, even with no delay, is at least partially dependent on muscarinic signaling in the OB.

  6. Long-term potentiation and olfactory memory formation in the carp (Cyprinus carpio L.) olfactory bulb.

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    Satou, M; Anzai, S; Huruno, M

    2005-05-01

    Long-term potentiation of synaptic transmission is considered to be an elementary process underlying the cellular mechanism of memory formation. In the present study we aimed to examine whether or not the dendrodendritic mitral-to-granule cell synapses in the carp olfactory bulb show plastic changes after their repeated activation. It was found that: (1) the dendrodendritic mitral-to-granule cell synapses showed three types of plasticity after tetanic electrical stimulation applied to the olfactory tract-long-term potentiation (potentiation lasting >1 h), short-term potentiation (potentiation lasting 1 h) of the odor-evoked bulbar response accompanied the electrically-induced LTP, and; (4) repeated olfactory stimulation enhanced dendrodendritic mitral-to-granule cell transmission. Based on these results, it was proposed that long-term potentiation (as well as olfactory memory) occurs at the dendrodendritic mitral-to-granule cell synapses after strong and long-lasting depolarization of granule cells, which follows repeated and simultaneous synaptic activation of both the peripheral and deep dendrites (or somata).

  7. Nonlinear dynamics of pattern formation and pattern recognition in the rabbit olfactory bulb

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    Baird, Bill

    1986-10-01

    A mathematical model of the process of pattern recognition in the first olfactory sensory cortex of the rabbit is presented. It explains the formation and alteration of spatial patterns in neural activity observed experimentally during classical Pavlovian conditioning. On each inspiration of the animal, a surge of receptor input enters the olfactory bulb. EEG activity recorded at the surface of the bulb undergoes a transition from a low amplitude background state of temporal disorder to coherent oscillation. There is a distinctive spatial pattern of rms amplitude in this oscillation which changes reliably to a second pattern during each successful recognition by the animal of a conditioned stimulus odor. When a new odor is paired as conditioned stimulus, these patterns are replaced by new patterns that stabilize as the animal adapts to the new environment. I will argue that a unification of the theories of pattern formation and associative memory is required to account for these observations. This is achieved in a model of the bulb as a discrete excitable medium with spatially inhomogeneous coupling expressed by a connection matrix. The theory of multiple Hopf bifurcations is employed to find coupled equations for the amplitudes of competing unstable oscillatory modes. These may be created in the system by proper coupling and selectively evoked by specific classes of inputs. This allows a view of limit cycle attractors as “stored” fixed points of a gradient vector field and thereby recovers the more familiar dynamical systems picture of associative memory.

  8. A functional study of the rat olfactory bulb through autoradiography with 14C-2-deoxyglucose

    International Nuclear Information System (INIS)

    Verrier, Marie; Leveteau, Jean; Giachetti, Ismene; MacLeod, Patrick

    1978-01-01

    The autoradiographic methods has been used in the rat to map active regions in the olfactory bulb after a pulse of 14 C-2-deoxyglucose with electrical stimulation of the lateral olfactory tract. The highest optical densities were found at the external plexiform, mural, internal plexiform and granular layers: the lowest was found in the glomerular layer [fr

  9. Topological reorganization of odor representations in the olfactory bulb.

    Directory of Open Access Journals (Sweden)

    Emre Yaksi

    2007-07-01

    Full Text Available Odors are initially represented in the olfactory bulb (OB by patterns of sensory input across the array of glomeruli. Although activated glomeruli are often widely distributed, glomeruli responding to stimuli sharing molecular features tend to be loosely clustered and thus establish a fractured chemotopic map. Neuronal circuits in the OB transform glomerular patterns of sensory input into spatiotemporal patterns of output activity and thereby extract information about a stimulus. It is, however, unknown whether the chemotopic spatial organization of glomerular inputs is maintained during these computations. To explore this issue, we measured spatiotemporal patterns of odor-evoked activity across thousands of individual neurons in the zebrafish OB by temporally deconvolved two-photon Ca(2+ imaging. Mitral cells and interneurons were distinguished by transgenic markers and exhibited different response selectivities. Shortly after response onset, activity patterns exhibited foci of activity associated with certain chemical features throughout all layers. During the subsequent few hundred milliseconds, however, MC activity was locally sparsened within the initial foci in an odor-specific manner. As a consequence, chemotopic maps disappeared and activity patterns became more informative about precise odor identity. Hence, chemotopic maps of glomerular input activity are initially transmitted to OB outputs, but not maintained during pattern processing. Nevertheless, transient chemotopic maps may support neuronal computations by establishing important synaptic interactions within the circuit. These results provide insights into the functional topology of neural activity patterns and its potential role in circuit function.

  10. Not all sharks are "swimming noses": variation in olfactory bulb size in cartilaginous fishes.

    Science.gov (United States)

    Yopak, Kara E; Lisney, Thomas J; Collin, Shaun P

    2015-03-01

    Olfaction is a universal modality by which all animals sample chemical stimuli from their environment. In cartilaginous fishes, olfaction is critical for various survival tasks including localizing prey, avoiding predators, and chemosensory communication with conspecifics. Little is known, however, about interspecific variation in olfactory capability in these fishes, or whether the relative importance of olfaction in relation to other sensory systems varies with regard to ecological factors, such as habitat and lifestyle. In this study, we have addressed these questions by directly examining interspecific variation in the size of the olfactory bulbs (OB), the region of the brain that receives the primary sensory projections from the olfactory nerve, in 58 species of cartilaginous fishes. Relative OB size was compared among species occupying different ecological niches. Our results show that the OBs maintain a substantial level of allometric independence from the rest of the brain across cartilaginous fishes and that OB size is highly variable among species. These findings are supported by phylogenetic generalized least-squares models, which show that this variability is correlated with ecological niche, particularly habitat. The relatively largest OBs were found in pelagic-coastal/oceanic sharks, especially migratory species such as Carcharodon carcharias and Galeocerdo cuvier. Deep-sea species also possess large OBs, suggesting a greater reliance on olfaction in habitats where vision may be compromised. In contrast, the smallest OBs were found in the majority of reef-associated species, including sharks from the families Carcharhinidae and Hemiscyllidae and dasyatid batoids. These results suggest that there is great variability in the degree to which these fishes rely on olfactory cues. The OBs have been widely used as a neuroanatomical proxy for olfactory capability in vertebrates, and we speculate that differences in olfactory capabilities may be the result of

  11. Prenatal Alcohol Exposure Affects Progenitor Cell Numbers in Olfactory Bulbs and Dentate Gyrus of Vervet Monkeys

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    Mark W. Burke

    2016-10-01

    Full Text Available Fetal alcohol exposure (FAE alters hippocampal cell numbers in rodents and primates, and this may be due, in part, to a reduction in the number or migration of neuronal progenitor cells. The olfactory bulb exhibits substantial postnatal cellular proliferation and a rapid turnover of newly formed cells in the rostral migratory pathway, while production and migration of postnatal neurons into the dentate gyrus may be more complex. The relatively small size of the olfactory bulb, compared to the hippocampus, potentially makes this structure ideal for a rapid analysis. This study used the St. Kitts vervet monkey (Chlorocebus sabeus to (1 investigate the normal developmental sequence of post-natal proliferation in the olfactory bulb and dentate gyrus and (2 determine the effects of naturalistic prenatal ethanol exposure on proliferation at three different ages (neonate, five months and two years. Using design-based stereology, we found an age-related decrease of actively proliferating cells in the olfactory bulb and dentate gyrus for both control and FAE groups. Furthermore, at the neonatal time point, the FAE group had fewer actively proliferating cells as compared to the control group. These data are unique with respect to fetal ethanol effects on progenitor proliferation in the primate brain and suggest that the olfactory bulb may be a useful structure for studies of cellular proliferation.

  12. Electrophysiological mapping of the accessory olfactory bulb of the rabbit (Oryctolagus cuniculus).

    Science.gov (United States)

    van Groen, T; Ruardy, L; da Silva, F H

    1986-07-01

    Field potentials elicited by electrical stimulation of the vomeronasal nerve were measured in the accessory olfactory bulb of the rabbit. Maps were made of the distribution of surface field potentials and of the corresponding depth profiles. The surface maps followed closely the contours of the accessory olfactory bulb: at the frontal border the field potential tended to zero and at the center of the structure the field potential attained a maximum. Depth profiles of the field potentials through the accessory olfactory bulb presented a surface-negative wave and, in depth, a positive wave. The polarity reversal occurred at the deep part of the granule cell layer. The zero equipotential line followed closely the curvature of the granule cell layer. Current source density analysis of the depth profiles revealed a main sink at the external plexiform and granule cell layers. This indicates that the main activity in the accessory olfactory bulb is generated by the synapses between the mitral cells and the granule cells as is found in the main olfactory bulb.

  13. Understanding odor information segregation in the olfactory bulb by means of mitral and tufted cells.

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    Davide Polese

    Full Text Available Odor identification is one of the main tasks of the olfactory system. It is performed almost independently from the concentration of the odor providing a robust recognition. This capacity to ignore concentration information does not preclude the olfactory system from estimating concentration itself. Significant experimental evidence has indicated that the olfactory system is able to infer simultaneously odor identity and intensity. However, it is still unclear at what level or levels of the olfactory pathway this segregation of information occurs. In this work, we study whether this odor information segregation is performed at the input stage of the olfactory bulb: the glomerular layer. To this end, we built a detailed neural model of the glomerular layer based on its known anatomical connections and conducted two simulated odor experiments. In the first experiment, the model was exposed to an odor stimulus dataset composed of six different odorants, each one dosed at six different concentrations. In the second experiment, we conducted an odor morphing experiment where a sequence of binary mixtures going from one odor to another through intermediate mixtures was presented to the model. The results of the experiments were visualized using principal components analysis and analyzed with hierarchical clustering to unveil the structure of the high-dimensional output space. Additionally, Fisher's discriminant ratio and Pearson's correlation coefficient were used to quantify odor identity and odor concentration information respectively. Our results showed that the architecture of the glomerular layer was able to mediate the segregation of odor information obtaining output spiking sequences of the principal neurons, namely the mitral and external tufted cells, strongly correlated with odor identity and concentration, respectively. An important conclusion is also that the morphological difference between the principal neurons is not key to achieve odor

  14. Respiration Gates Sensory Input Responses in the Mitral Cell Layer of the Olfactory Bulb

    Science.gov (United States)

    Short, Shaina M.; Morse, Thomas M.; McTavish, Thomas S.; Shepherd, Gordon M.; Verhagen, Justus V.

    2016-01-01

    Respiration plays an essential role in odor processing. Even in the absence of odors, oscillating excitatory and inhibitory activity in the olfactory bulb synchronizes with respiration, commonly resulting in a burst of action potentials in mammalian mitral/tufted cells (MTCs) during the transition from inhalation to exhalation. This excitation is followed by inhibition that quiets MTC activity in both the glomerular and granule cell layers. Odor processing is hypothesized to be modulated by and may even rely on respiration-mediated activity, yet exactly how respiration influences sensory processing by MTCs is still not well understood. By using optogenetics to stimulate discrete sensory inputs in vivo, it was possible to temporally vary the stimulus to occur at unique phases of each respiration. Single unit recordings obtained from the mitral cell layer were used to map spatiotemporal patterns of glomerular evoked responses that were unique to stimulations occurring during periods of inhalation or exhalation. Sensory evoked activity in MTCs was gated to periods outside phasic respiratory mediated firing, causing net shifts in MTC activity across the cycle. In contrast, odor evoked inhibitory responses appear to be permitted throughout the respiratory cycle. Computational models were used to further explore mechanisms of inhibition that can be activated by respiratory activity and influence MTC responses. In silico results indicate that both periglomerular and granule cell inhibition can be activated by respiration to internally gate sensory responses in the olfactory bulb. Both the respiration rate and strength of lateral connectivity influenced inhibitory mechanisms that gate sensory evoked responses. PMID:28005923

  15. Prenatal alcohol exposure affects progenitor cell numbers in olfactory bulbs and dentate gyrus of vervet monkeys

    DEFF Research Database (Denmark)

    Burke, Mark W; Inyatkin, Alexey; Ptito, Maurice

    2016-01-01

    vervet monkey (Chlorocebus sabeus) to (1) investigate the normal developmental sequence of post-natal proliferation in the olfactory bulb and dentate gyrus and (2) determine the effects of naturalistic prenatal ethanol exposure on proliferation at three different ages (neonate, five months and two years......). Using design-based stereology, we found an age-related decrease of actively proliferating cells in the olfactory bulb and dentate gyrus for both control and FAE groups. Furthermore, at the neonatal time point, the FAE group had fewer actively proliferating cells as compared to the control group...

  16. Calcium Signaling in Mitral Cell Dendrites of Olfactory Bulbs of Neonatal Rats and Mice during Olfactory Nerve Stimulation and Beta-Adrenoceptor Activation

    Science.gov (United States)

    Yuan, Qi; Mutoh, Hiroki; Debarbieux, Franck; Knopfel, Thomas

    2004-01-01

    Synapses formed by the olfactory nerve (ON) provide the source of excitatory synaptic input onto mitral cells (MC) in the olfactory bulb. These synapses, which relay odor-specific inputs, are confined to the distally tufted single primary dendrites of MCs, the first stage of central olfactory processing. Beta-adrenergic modulation of electrical…

  17. Direct transport of inhaled xylene and its metabolites from the olfactory mucosa to the glomeruli of the olfactory bulbs

    International Nuclear Information System (INIS)

    Lewis, J.L.; Dahl, A.R.; Kracko, D.A.

    1994-01-01

    The olfactory epithelium is a unique tissue in that single receptor neurons have dendrites in contact with the external environment at the nasal airway, and axon terminals that penetrate the cribriform plate and synapse in the olfactory bulb. The Central Nervous System (CNS) is protected from systematically circulating toxicants by a blood-brain barrier primarily composed of tight junctions between endothelial cells in cerebral vessels and a high metabolic capacity within these cells. No such barrier has yet been defined to protect the CNS from inhaled toxicants. Because all inhalants do not seem to access the CNS directly, a nose-brain barrier seems plausible. The purpose of the work described here is to determine whether or not a nose-brain barrier exists and to define its components. Although such a barrier is likely to be multi-faceted, the present work focuses only on the importance of gross histologic and metabolic characteristics of the olfactory epithelium in olfactory transport

  18. Implementation of Olfactory Bulb Glomerular Layer Computations in a Digital Neurosynaptic Core

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    Nabil eImam

    2012-06-01

    Full Text Available We present a biomimetic system that captures essential functional properties of the glomerular layer of the mammalian olfactory bulb, specifically including its capacity to decorrelate similar odor representations without foreknowledge of the statistical distributions of analyte features. Our system is based on a digital neuromorphic chip consisting of 256 leaky-integrate-and-fire neurons, 1024x256 crossbar synapses, and AER communication circuits. The neural circuits configured in the chip reflect established connections among mitral cells, periglomerular cells, external tufted cells and superficial short axon cells within the olfactory bulb, and accept input from convergent sets of sensors configured as olfactory sensory neurons. This configuration generates functional transformations comparable to those observed in the glomerular layer of the mammalian olfactory bulb. Our circuits, consuming only 45 pJ of active power per spike with a power supply voltage of 0.85V, can be used as the first stage of processing in low-power artificial chemical sensing devices inspired by natural olfactory systems.

  19. Implementation of olfactory bulb glomerular-layer computations in a digital neurosynaptic core.

    Science.gov (United States)

    Imam, Nabil; Cleland, Thomas A; Manohar, Rajit; Merolla, Paul A; Arthur, John V; Akopyan, Filipp; Modha, Dharmendra S

    2012-01-01

    We present a biomimetic system that captures essential functional properties of the glomerular layer of the mammalian olfactory bulb, specifically including its capacity to decorrelate similar odor representations without foreknowledge of the statistical distributions of analyte features. Our system is based on a digital neuromorphic chip consisting of 256 leaky-integrate-and-fire neurons, 1024 × 256 crossbar synapses, and address-event representation communication circuits. The neural circuits configured in the chip reflect established connections among mitral cells, periglomerular cells, external tufted cells, and superficial short-axon cells within the olfactory bulb, and accept input from convergent sets of sensors configured as olfactory sensory neurons. This configuration generates functional transformations comparable to those observed in the glomerular layer of the mammalian olfactory bulb. Our circuits, consuming only 45 pJ of active power per spike with a power supply of 0.85 V, can be used as the first stage of processing in low-power artificial chemical sensing devices inspired by natural olfactory systems.

  20. Vaginocervical stimulation enhances social recognition memory in rats via oxytocin release in the olfactory bulb.

    Science.gov (United States)

    Larrazolo-López, A; Kendrick, K M; Aburto-Arciniega, M; Arriaga-Avila, V; Morimoto, S; Frias, M; Guevara-Guzmán, R

    2008-03-27

    The ability of vaginocervical stimulation (VCS) to promote olfactory social recognition memory at different stages of the ovarian cycle was investigated in female rats. A juvenile social recognition paradigm was used and memory retention tested at 30 and 300 min after an adult was exposed to a juvenile during three 4-min trials. Results showed that an intact social recognition memory was present at 30 min in animals with or without VCS and at all stages of the estrus cycle. However, whereas no animals in any stage of the estrus cycle showed retention of the specific recognition memory at 300 min, those in the proestrus/estrus phase that received VCS 10 min before the trial started did. In vivo microdialysis studies showed that there was a significant release of oxytocin after VCS in the olfactory bulb during proestrus. There was also increased oxytocin immunoreactivity within the olfactory bulb after VCS in proestrus animals compared with diestrus ones. Furthermore, when animals received an infusion of an oxytocin antagonist directly into the olfactory bulb, or a systemic administration of alpha or beta noradrenaline-antagonists, they failed to show evidence for maintenance of a selective olfactory recognition memory at 300 min. Animals with vagus or pelvic nerve section also showed no memory retention when tested after 300 min. These results suggest that VCS releases oxytocin in the olfactory bulb to enhance the social recognition memory and that this may be due to modulatory actions on noradrenaline release. The vagus and pelvic nerves are responsible for carrying the information from the pelvic area to the CNS.

  1. [3H]GABA uptake as a marker for cell type in primary cultures of cerebellum and olfactory bulb

    International Nuclear Information System (INIS)

    Currie, D.N.; Dutton, G.R.

    1980-01-01

    Uptake of [ 3 H]GABA into cell cultures of rat cerebellum and olfactory bulb was studied by autoradiography, using β-alanine and aminocyclohexane carboxylic acid to distinguish neuronal-specific and glial-specific uptake. Neurons and astrocytes were also labelled by tetanus toxin and anti-GFAP respectively. This combination of markers allowed identification and quantification of several cell types. Cerebellar cultures were found to contain 77% granule neurons, 7.5% inhibitory neurons (probably stellate and basket cells) and 15% astrocytes. Olfactory bulb cultures were over 50% in small neurons which accumulated GABA, the olfactory bulb granule neuron being GABAergic in vivo. (Auth.)

  2. Regulation of spike timing-dependent plasticity of olfactory inputs in mitral cells in the rat olfactory bulb.

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    Teng-Fei Ma

    Full Text Available The recent history of activity input onto granule cells (GCs in the main olfactory bulb can affect the strength of lateral inhibition, which functions to generate contrast enhancement. However, at the plasticity level, it is unknown whether and how the prior modification of lateral inhibition modulates the subsequent induction of long-lasting changes of the excitatory olfactory nerve (ON inputs to mitral cells (MCs. Here we found that the repetitive stimulation of two distinct excitatory inputs to the GCs induced a persistent modification of lateral inhibition in MCs in opposing directions. This bidirectional modification of inhibitory inputs differentially regulated the subsequent synaptic plasticity of the excitatory ON inputs to the MCs, which was induced by the repetitive pairing of excitatory postsynaptic potentials (EPSPs with postsynaptic bursts. The regulation of spike timing-dependent plasticity (STDP was achieved by the regulation of the inter-spike-interval (ISI of the postsynaptic bursts. This novel form of inhibition-dependent regulation of plasticity may contribute to the encoding or processing of olfactory information in the olfactory bulb.

  3. Continuous spatial representations in the olfactory bulb may reflect perceptual categories

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    Benjamin eAuffarth

    2011-10-01

    Full Text Available In sensory processing of odors, the olfactory bulb is an important relay station, where odor representations are noise-filtered, sharpened, and possibly re-organized. An organization by perceptual qualities has been found previously in the piriform cortex, however several recent studies indicate that the olfactory bulb code reflects behaviorally relevant dimensions spatially as well as at the population level. We apply a statistical analysis on 2-deoxyglucose images, taken over the entire bulb of glomerular layer of the rat, in order to see how the recognition of odors in the nose is translated into a map of odor quality in the brain. We first confirm previous studies that the first principal component could be related to pleasantness, however the next higher principal components are not directly clear. We then find mostly continuous spatial representations for perceptual categories. We compare the space spanned by spatial and population codes to human reports of perceptual similarity between odors and our results suggest that perceptual categories could be already embedded in glomerular activations and that spatial representations give a better match than population codes. This suggests that human and rat perceptual dimensions of odorant coding are related and indicates that perceptual qualities could be represented as continuous spatial codes of the olfactory bulb glomerulus population.

  4. Odor preference learning and memory modify GluA1 phosphorylation and GluA1 distribution in the neonate rat olfactory bulb: testing the AMPA receptor hypothesis in an appetitive learning model.

    Science.gov (United States)

    Cui, Wen; Darby-King, Andrea; Grimes, Matthew T; Howland, John G; Wang, Yu Tian; McLean, John H; Harley, Carolyn W

    2011-01-01

    An increase in synaptic AMPA receptors is hypothesized to mediate learning and memory. AMPA receptor increases have been reported in aversive learning models, although it is not clear if they are seen with memory maintenance. Here we examine AMPA receptor changes in a cAMP/PKA/CREB-dependent appetitive learning model: odor preference learning in the neonate rat. Rat pups were given a single pairing of peppermint and 2 mg/kg isoproterenol, which produces a 24-h, but not a 48-h, peppermint preference in the 7-d-old rat pup. GluA1 PKA-dependent phosphorylation peaked 10 min after the 10-min training trial and returned to baseline within 90 min. At 24 h, GluA1 subunits did not change overall but were significantly increased in synaptoneurosomes, consistent with increased membrane insertion. Immunohistochemistry revealed a significant increase in GluA1 subunits in olfactory bulb glomeruli, the targets of olfactory nerve axons. Glomerular increases were seen at 3 and 24 h after odor exposure in trained pups, but not in control pups. GluA1 increases were not seen as early as 10 min after training and were no longer observed 48 h after training when odor preference is no longer expressed behaviorally. Thus, the pattern of increased GluA1 membrane expression closely follows the memory timeline. Further, blocking GluA1 insertion using an interference peptide derived from the carboxyl tail of the GluA1 subunit inhibited 24 h odor preference memory providing causative support for our hypothesis. PKA-mediated GluA1 phosphorylation and later GluA1 insertion could, conjointly, provide increased AMPA function to support both short-term and long-term appetitive memory.

  5. Participation of the Olfactory Bulb in Circadian Organization during Early Postnatal Life in Rabbits.

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    Erika Navarrete

    Full Text Available Experimental evidence indicates that during pre-visual stages of development in mammals, circadian regulation is still not under the control of the light-entrainable hypothalamic pacemaker, raising the possibility that the circadian rhythmicity that occurs during postnatal development is under the control of peripheral oscillators, such as the main olfactory bulb (MOB. We evaluated the outcome of olfactory bulbectomy on the temporal pattern of core body temperature and gross locomotor activity in newborn rabbits. From postnatal day 1 (P1, pups were randomly assigned to one of the following conditions: intact pups (INT, intact pups fed by enteral gavage (INT+ENT, sham operated pups (SHAM, pups with unilateral lesions of the olfactory bulb (OBx-UNI, and pups with bilateral lesions of the olfactory bulb (OBx-BI. At the beginning of the experiment, from P1-8, the animals in all groups were fed at 11:00, from P9-13 the feeding schedule was delayed 6 h (17:00, and finally, from P14-15 the animals were subjected to fasting conditions. The rabbit pups of the INT, INT+ENT, SHAM and OBx-UNI groups exhibited a clear circadian rhythmicity in body temperature and locomotor activity, with a conspicuous anticipatory rise hours prior to the nursing or feeding schedule, which persisted even during fasting conditions. In addition, phase delays in the nursing or feeding schedule induced a clear phase shift in both parameters. In contrast, the OBx-BI group exhibited atypical rhythmicity in both parameters under entrained conditions that altered the anticipatory component, as well as deficient phase control of both rhythms. The present results demonstrate that the expression of circadian rhythmicity at behavioral and physiological levels during early stages of rabbit development largely depends on the integrity of the main olfactory bulb.

  6. In Vivo Study of Dynamics and Stability of Dendritic Spines on Olfactory Bulb Interneurons in Xenopus laevis Tadpoles.

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    Yu-Bin Huang

    Full Text Available Dendritic spines undergo continuous remodeling during development of the nervous system. Their stability is essential for maintaining a functional neuronal circuit. Spine dynamics and stability of cortical excitatory pyramidal neurons have been explored extensively in mammalian animal models. However, little is known about spiny interneurons in non-mammalian vertebrate models. In the present study, neuronal morphology was visualized by single-cell electroporation. Spiny neurons were surveyed in the Xenopus tadpole brain and observed to be widely distributed in the olfactory bulb and telencephalon. DsRed- or PSD95-GFP-expressing spiny interneurons in the olfactory bulb were selected for in vivo time-lapse imaging. Dendritic protrusions were classified as filopodia, thin, stubby, or mushroom spines based on morphology. Dendritic spines on the interneurons were highly dynamic, especially the filopodia and thin spines. The stubby and mushroom spines were relatively more stable, although their stability significantly decreased with longer observation intervals. The 4 spine types exhibited diverse preferences during morphological transitions from one spine type to others. Sensory deprivation induced by severing the olfactory nerve to block the input of mitral/tufted cells had no significant effects on interneuron spine stability. Hence, a new model was established in Xenopus laevis tadpoles to explore dendritic spine dynamics in vivo.

  7. Reduction of Glucose Metabolism in Olfactory Bulb is an Earlier Alzheimer's Disease-related Biomarker in 5XFAD Mice

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    Nai-An Xiao

    2015-01-01

    Conclusions: The decline of (18F-FDG uptake in the olfactory bulb occurs earlier than other incidents, serving as an earlier in vivo biological marker of AD in 5XFAD mice and making early diagnosis of AD possibly.

  8. Pattern separation: a common function for new neurons in hippocampus and olfactory bulb.

    Science.gov (United States)

    Sahay, Amar; Wilson, Donald A; Hen, René

    2011-05-26

    While adult-born neurons in the olfactory bulb (OB) and the dentate gyrus (DG) subregion of the hippocampus have fundamentally different properties, they may have more in common than meets the eye. Here, we propose that new granule cells in the OB and DG may function as modulators of principal neurons to influence pattern separation and that adult neurogenesis constitutes an adaptive mechanism to optimally encode contextual or olfactory information. See the related Perspective from Aimone, Deng, and Gage, "Resolving New Memories: A Critical Look at the Dentate Gyrus, Adult Neurogenesis, and Pattern Separation," in this issue of Neuron. Copyright © 2011 Elsevier Inc. All rights reserved.

  9. Differences in peripheral sensory input to the olfactory bulb between male and female mice

    Science.gov (United States)

    Kass, Marley D.; Czarnecki, Lindsey A.; Moberly, Andrew H.; McGann, John P.

    2017-04-01

    Female mammals generally have a superior sense of smell than males, but the biological basis of this difference is unknown. Here, we demonstrate sexually dimorphic neural coding of odorants by olfactory sensory neurons (OSNs), primary sensory neurons that physically contact odor molecules in the nose and provide the initial sensory input to the brain’s olfactory bulb. We performed in vivo optical neurophysiology to visualize odorant-evoked OSN synaptic output into olfactory bub glomeruli in unmanipulated (gonad-intact) adult mice from both sexes, and found that in females odorant presentation evoked more rapid OSN signaling over a broader range of OSNs than in males. These spatiotemporal differences enhanced the contrast between the neural representations of chemically related odorants in females compared to males during stimulus presentation. Removing circulating sex hormones makes these signals slower and less discriminable in females, while in males they become faster and more discriminable, suggesting opposite roles for gonadal hormones in influencing male and female olfactory function. These results demonstrate that the famous sex difference in olfactory abilities likely originates in the primary sensory neurons, and suggest that hormonal modulation of the peripheral olfactory system could underlie differences in how males and females experience the olfactory world.

  10. Synchronized Activity in The Main and Accessory Olfactory Bulbs and Vomeronasal Amygdala Elicited by Chemical Signals in Freely Behaving Mice.

    Science.gov (United States)

    Pardo-Bellver, Cecília; Martínez-Bellver, Sergio; Martínez-García, Fernando; Lanuza, Enrique; Teruel-Martí, Vicent

    2017-08-30

    Chemosensory processing in mammals involves the olfactory and vomeronasal systems, but how the activity of both circuits is integrated is unknown. In our study, we recorded the electrophysiological activity in the olfactory bulbs and the vomeronasal amygdala in freely behaving mice exploring a battery of neutral and conspecific stimuli. The exploration of stimuli, including a neutral stimulus, induced synchronic activity in the olfactory bulbs characterized by a dominant theta rhythmicity, with specific theta-gamma coupling, distinguishing between vomeronasal and olfactory structures. The correlated activation of the bulbs suggests a coupling between the stimuli internalization in the nasal cavity and the vomeronasal pumping. In the amygdala, male stimuli are preferentially processed in the medial nucleus, whereas female cues induced a differential response in the posteromedial cortical amygdala. Thus, particular theta-gamma patterns in the olfactory network modulates the integration of chemosensory information in the amygdala, allowing the selection of an appropriate behaviour.

  11. Endogenous GABA and Glutamate Finely Tune the Bursting of Olfactory Bulb External Tufted Cells

    Science.gov (United States)

    Hayar, Abdallah; Ennis, Matthew

    2008-01-01

    In rat olfactory bulb slices, external tufted (ET) cells spontaneously generate spike bursts. Although ET cell bursting is intrinsically generated, its strength and precise timing may be regulated by synaptic input. We tested this hypothesis by analyzing whether the burst properties are modulated by activation of ionotropic γ-aminobutyric acid (GABA) and glutamate receptors. Blocking GABAA receptors increased—whereas blocking ionotropic glutamate receptors decreased—the number of spikes/burst without changing the interburst frequency. The GABAA agonist (isoguvacine, 10 μM) completely inhibited bursting or reduced the number of spikes/burst, suggesting a shunting effect. These findings indicate that the properties of ET cell spontaneous bursting are differentially controlled by GABAergic and glutamatergic fast synaptic transmission. We suggest that ET cell excitatory and inhibitory inputs may be encoded as a change in the pattern of spike bursting in ET cells, which together with mitral/tufted cells constitute the output circuit of the olfactory bulb. PMID:17567771

  12. 17β-estradiol enhances memory duration in the main olfactory bulb in CD-1 mice.

    Science.gov (United States)

    Dillon, T Samuel; Fox, Laura C; Han, Crystal; Linster, Christiane

    2013-12-01

    Rodents rely heavily on odor detection, discrimination, and memory to locate food, find mates, care for pups, and avoid predators. Estrogens have been shown to increase memory retention in rodents performing spatial memory and object placement tasks. Here we evaluate the extent to which 17β-estradiol modulates memory formation and duration in the olfactory system. Adult CD-1 mice were gonadectomized and given either systemic 17β-estradiol replacement, local 17β-estradiol in the main olfactory bulb, or no replacement. Before performing the behavioral task the mice were given saline or PHTPP (an estrogen receptor β [ER-β] antagonist) via bilateral infusion into the main olfactory bulb. As the beta-type estrogen receptor (ER-β) is more abundant than the alpha-type estrogen receptor in the murine main olfactory bulb, the current study focuses on 17β-estradiol and its interactions with ERβ. Habituation, a simple, nonassociative learning task in which an animal is exposed to the same odor over successive presentations, was used to evaluate the animals' ability to detect odors and form an olfactory memory. To evaluate memory duration, we added a final trial of intertrial interval time (30 or 60 min) in which we presented the habituated odor. Neither surgical nor drug manipulation affected the ability of mice to detect or habituate to an odor. After habituation, gonadectomized 17β-estradiol-treated mice retained memory of an odor for 30 min, whereas non-estradiol-treated, 17β-estradiol+ERβ antagonist (PHTPP), and untreated male mice did not remember an odor 30 min after habituation. The results show that both systemic and local bulbar infusions of 17β-estradiol enhance odor memory duration in mice.

  13. Stimulation of the Locus Ceruleus Modulates Signal-to-Noise Ratio in the Olfactory Bulb.

    Science.gov (United States)

    Manella, Laura C; Petersen, Nicholas; Linster, Christiane

    2017-11-29

    Norepinephrine (NE) has been shown to influence sensory, and specifically olfactory processing at the behavioral and physiological levels, potentially by regulating signal-to-noise ratio (S/N). The present study is the first to look at NE modulation of olfactory bulb (OB) in regards to S/N in vivo We show, in male rats, that locus ceruleus stimulation and pharmacological infusions of NE into the OB modulate both spontaneous and odor-evoked neural responses. NE in the OB generated a non-monotonic dose-response relationship, suppressing mitral cell activity at high and low, but not intermediate, NE levels. We propose that NE enhances odor responses not through direct potentiation of the afferent signal per se, but rather by reducing the intrinsic noise of the system. This has important implications for the ways in which an animal interacts with its olfactory environment, particularly as the animal shifts from a relaxed to an alert behavioral state. SIGNIFICANCE STATEMENT Sensory perception can be modulated by behavioral states such as hunger, fear, stress, or a change in environmental context. Behavioral state often affects neural processing via the release of circulating neurochemicals such as hormones or neuromodulators. We here show that the neuromodulator norepinephrine modulates olfactory bulb spontaneous activity and odor responses so as to generate an increased signal-to-noise ratio at the output of the olfactory bulb. Our results help interpret and improve existing ideas for neural network mechanisms underlying behaviorally observed improvements in near-threshold odor detection and discrimination. Copyright © 2017 the authors 0270-6474/17/3711605-11$15.00/0.

  14. Stressors impair odor recognition memory via an olfactory bulb-dependent noradrenergic mechanism

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    Laura C Manella

    2013-12-01

    Full Text Available Non-associative habituation and odor recognition tasks have been widely used to probe questions social recognition, odor memory duration, and odor memory specificity. Among others, these paradigms have provided valuable insight into how neuromodulation, and specifically norepinephrine/noradrenaline (NE influences odor memory. In general, NE levels are modulated by arousal, stress, and behavioral state, and there is sparse evidence of a direct relationship between NE and odor memory in adult rodents. The present study uses simple mild psychological stressors (bright light and sound, to modulate NE levels physiologically in order to probe its effect on olfactory memory. In rats with bilateral bulbar cannulations, we show that these stressors modulate olfactory memory and that this effect is at least partially mediated by olfactory bulb. Specifically, we show that the presence of stressors during the acquisition of odor memory suppresses memory for an odor when tested 30 minutes after the acquisition. This suppression is blocked by infusing NE antagonists into the olfactory bulb prior to odor acquisition. Additionally, we find that infusion of bulbar NE is sufficient to suppress odor memory in a manner mimicking that of our stressors. These effects are unlikely to be solely mediated by locomotor/exploratory changes produced by stressors, although these stressors influence certain behaviors not directly related to odor investigation. This study provides important information about how behaviorally relevant changes in NE can influence top-down sensory processing and odor memory.

  15. Blocking muscarinic receptors in the olfactory bulb impairs performance on an olfactory short-term memory task.

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    Devore, Sasha; Manella, Laura C; Linster, Christiane

    2012-01-01

    Cholinergic inputs to cortical processing networks have long been associated with attentional and top-down processing. Experimental and theoretical studies suggest that cholinergic inputs to the main olfactory bulb (OB) can modulate both neural and behavioral odor discrimination. Previous experiments from our laboratory and others demonstrate that blockade of nicotinic receptors directly impairs olfactory discrimination, whereas blockade of muscarinic receptors only measurably impairs olfactory perception when task demands are made more challenging, such as when very low-concentration odors are used or rats are required to maintain sensory memory over long durations. To further investigate the role of muscarinic signaling in the OB, we developed an olfactory delayed match-to-sample task using a digging-based behavioral paradigm. We find that rats are able to maintain robust short-term odor memory for 10-100 s. To investigate the role of muscarinic signaling in task performance, we bilaterally infused scopolamine into the OB. We find that high dosages of scopolamine (38 mM) impair performance on the task across all delays tested, including the baseline condition with no delay, whereas lower dosages (7.6 mM and 22.8 mM) had no measureable effects. These results indicate that general execution of the match-to-sample task, even with no delay, is at least partially dependent on muscarinic signaling in the OB.

  16. Associations of olfactory bulb and depth of olfactory sulcus with basal ganglia and hippocampus in patients with Parkinson's disease.

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    Tanik, Nermin; Serin, Halil Ibrahim; Celikbilek, Asuman; Inan, Levent Ertugrul; Gundogdu, Fatma

    2016-05-04

    Parkinson's disease (PD) is a neurodegenerative disorder characterized by hyposmia in the preclinical stages. We investigated the relationships of olfactory bulb (OB) volume and olfactory sulcus (OS) depth with basal ganglia and hippocampal volumes. The study included 25 patients with PD and 40 age- and sex-matched control subjects. Idiopathic PD was diagnosed according to published diagnostic criteria. The Hoehn and Yahr (HY) scale, the motor subscale of the Unified Parkinson's Disease Rating Scale (UPDRS III), and the Mini-Mental State Examination (MMSE) were administered to participants. Volumetric measurements of olfactory structures, the basal ganglia, and hippocampus were performed using magnetic resonance imaging (MRI). OB volume and OS depth were significantly reduced in PD patients compared to healthy control subjects (p<0.001 and p<0.001, respectively). The OB and left putamen volumes were significantly correlated (p=0.048), and the depth of the right OS was significantly correlated with right hippocampal volume (p=0.018). We found significant correlations between OB and putamen volumes and OS depth and hippocampal volume. Our study is the first to demonstrate associations of olfactory structures with the putamen and hippocampus using MRI volumetric measurements. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  17. Comprehensive connectivity of the mouse main olfactory bulb: analysis and online digital atlas

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    Houri eHintiryan

    2012-08-01

    Full Text Available We introduce the first open resource for mouse olfactory connectivity data produced as part of the Mouse Connectome Project (MCP at UCLA. The MCP aims to assemble a whole-brain connectivity atlas for the C57Bl/6J mouse using a double coinjection tracing method. Each coinjection consists of one anterograde and one retrograde tracer, which affords the advantage of simultaneously identifying efferent and afferent pathways and directly identifying reciprocal connectivity of injection sites. The systematic application of double coinjections potentially reveals interaction stations between injections and allows for the study of connectivity at the network level. To facilitate use of the data, raw images are made publicly accessible through our online interactive visualization tool, the iConnectome, where users can view and annotate the high-resolution, multi-fluorescent connectivity data (www.MouseConnectome.org. Systematic double coinjections were made into different regions of the main olfactory bulb (MOB and data from 18 MOB cases (~72 pathways; 36 efferent/36 afferent currently are available to view in iConnectome within their corresponding atlas level and their own bright-field cytoarchitectural background. Additional MOB injections and injections of the accessory olfactory bulb (AOB, anterior olfactory nucleus (AON, and other cortical olfactory areas gradually will be made available. Analysis of connections from different regions of the MOB revealed a novel, topographically arranged MOB projection roadmap, demonstrated disparate MOB connectivity with anterior versus posterior piriform cortical area, and exposed some novel aspects of well-established cortical olfactory projections.

  18. Neuronal and glial release of (3H)GABA from the rat olfactory bulb

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    Jaffe, E.H.; Cuello, A.C.

    1981-12-01

    Neuronal versus glial components of the (3H)gamma-aminobutyric acid ((3H)GABA) release studies were performed with two different microdissected layers of the olfactory bulb of the rat. In some experiments substantia nigra was used as a GABAergic axonal system and the trigeminal ganglia as a peripheral glial model. Spontaneous release of (3H)GABA was always lower in neuronal elements as compared with glial cells. A veratridine-evoked release was observed from the ONL but not from the trigeminal ganglia. Tetrodotoxin (TTX) abolished the veratridine-evoked release from the ONL, which also showed a partial inhibition when high magnesium concentrations were used in a Ca2+-free solution. beta-Alanine was strongly exchanged with (3H)GABA from the ONL of animals with the olfactory nerve lesioned and from animals with no lesion; but only a small heteroexchange was found from the external plexiform layer. The beta-alanine heteroexchange was able to deplete the releasable GABA store from the ONL of lesioned animals. In nonlesioned animals and the external plexiform layer, the veratridine-stimulated release of (3H)GABA was not significantly reduced after the beta-alanine heteroexchange. Stimulation of the (3H)GABA release by high concentrations of potassium elicited a higher release rate from axonal terminals than from dendrites or glia. Neurones and glia showed a similar inhibition of (3H)GABA release when a high magnesium concentration was added to a calcium-free solution. When D-600 was used as a calcium-flux blocker no inhibition of the release was observed in glial cells, whereas an almost complete blockage was found in both neuronal preparations (substantia nigra and EPL). These results provide further evidence for differential release mechanisms of GABA from CNS neurones and glial cells.

  19. [Oxidative metabolism of main and accessory olfactory bulbs, limpic system and hypothalamus during the estral cycle of the rat (author's transl)].

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    Sánchez-Criado, J E

    1979-06-01

    The in vitro oxidative metabolism of hypothalamus, olfactory and limbic systems from female rats in the estrous cycle have been measured. The accessory olfactory bulb becomes most active during diestrous when the hypothalamus reaches its lowest values.

  20. Prolonged Intracellular Na+ Dynamics Govern Electrical Activity in Accessory Olfactory Bulb Mitral Cells.

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    Asaph Zylbertal

    2015-12-01

    Full Text Available Persistent activity has been reported in many brain areas and is hypothesized to mediate working memory and emotional brain states and to rely upon network or biophysical feedback. Here, we demonstrate a novel mechanism by which persistent neuronal activity can be generated without feedback, relying instead on the slow removal of Na+ from neurons following bursts of activity. We show that mitral cells in the accessory olfactory bulb (AOB, which plays a major role in mammalian social behavior, may respond to a brief sensory stimulation with persistent firing. By combining electrical recordings, Ca2+ and Na+ imaging, and realistic computational modeling, we explored the mechanisms underlying the persistent activity in AOB mitral cells. We found that the exceptionally slow inward current that underlies this activity is governed by prolonged dynamics of intracellular Na+ ([Na+]i, which affects neuronal electrical activity via several pathways. Specifically, elevated dendritic [Na+]i reverses the Na+-Ca2+ exchanger activity, thus modifying the [Ca2+]i set-point. This process, which relies on ubiquitous membrane mechanisms, is likely to play a role in other neuronal types in various brain regions.

  1. Olfactory Bulb Field Potentials and Respiration in Sleep-Wake States of Mice.

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    Jessberger, Jakob; Zhong, Weiwei; Brankačk, Jurij; Draguhn, Andreas

    2016-01-01

    It is well established that local field potentials (LFP) in the rodent olfactory bulb (OB) follow respiration. This respiration-related rhythm (RR) in OB depends on nasal air flow, indicating that it is conveyed by sensory inputs from the nasal epithelium. Recently RR was found outside the olfactory system, suggesting that it plays a role in organizing distributed network activity. It is therefore important to measure RR and to delineate it from endogenous electrical rhythms like theta which cover similar frequency bands in small rodents. In order to validate such measurements in freely behaving mice, we compared rhythmic LFP in the OB with two respiration-related biophysical parameters: whole-body plethysmography (PG) and nasal temperature (thermocouple; TC). During waking, all three signals reflected respiration with similar reliability. Peak power of RR in OB decreased with increasing respiration rate whereas power of PG increased. During NREM sleep, respiration-related TC signals disappeared and large amplitude slow waves frequently concealed RR in OB. In this situation, PG provided a reliable signal while breathing-related rhythms in TC and OB returned only during microarousals. In summary, local field potentials in the olfactory bulb do reliably reflect respiratory rhythm during wakefulness and REM sleep but not during NREM sleep.

  2. Olfactory Bulb Field Potentials and Respiration in Sleep-Wake States of Mice

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    Jakob Jessberger

    2016-01-01

    Full Text Available It is well established that local field potentials (LFP in the rodent olfactory bulb (OB follow respiration. This respiration-related rhythm (RR in OB depends on nasal air flow, indicating that it is conveyed by sensory inputs from the nasal epithelium. Recently RR was found outside the olfactory system, suggesting that it plays a role in organizing distributed network activity. It is therefore important to measure RR and to delineate it from endogenous electrical rhythms like theta which cover similar frequency bands in small rodents. In order to validate such measurements in freely behaving mice, we compared rhythmic LFP in the OB with two respiration-related biophysical parameters: whole-body plethysmography (PG and nasal temperature (thermocouple; TC. During waking, all three signals reflected respiration with similar reliability. Peak power of RR in OB decreased with increasing respiration rate whereas power of PG increased. During NREM sleep, respiration-related TC signals disappeared and large amplitude slow waves frequently concealed RR in OB. In this situation, PG provided a reliable signal while breathing-related rhythms in TC and OB returned only during microarousals. In summary, local field potentials in the olfactory bulb do reliably reflect respiratory rhythm during wakefulness and REM sleep but not during NREM sleep.

  3. Role of olfactory bulb serotonin in olfactory learning in the greater short-nosed fruit bat, Cynopterus sphinx (Chiroptera: Pteropodidae).

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    Ganesh, Ambigapathy; Bogdanowicz, Wieslaw; Haupt, Moritz; Marimuthu, Ganapathy; Rajan, Koilmani Emmanuvel

    2010-09-17

    The role of olfactory bulb (OB) serotonin [5-hydroxytryptamine (5-HT)] in olfactory learning and memory was tested in the greater short-nosed fruit bat, Cynopterus sphinx (family Pteropodidae). Graded concentrations (25, 40, and 60microg) of 5,7-dihydroxytryptamine (5,7-DHT) or saline were injected into the OB of bats one day before training to the novel odor. In a behavioral test, 5,7-DHT (60microg) injected bats made significantly fewer feeding attempts and bouts when compared to saline-injected bats during learning and in the memory test. Subsequent biochemical analysis showed that 5-HT level was effectively depleted in the OB of 5,7-DHT injected bats. To test odor-induced 5-HT mediated changes in 5-HT receptors and second messenger cascade in the OB, we examined the expression of 5-HT receptors and mitogen-activated protein kinase (MAPK)/Erk cascade after training to the novel odor. We found that odor stimulation up-regulated the expression of 5-HT(1A) receptor, Erk1 and Creb1 mRNA, and phosphorylation of ERK1 and CREB1. Odor stimulation failed to induce expression in 5-HT-depleted bats, which is similar to control bats and significantly low compared to saline-treated bats. Together these data revealed that the level of 5-HT in the OB may regulate olfactory learning and memory in C. sphinx through Erk and CREB.

  4. Olfactory bulb and olfactory sulcus depths are associated with disease duration and attack frequency in multiple sclerosis patients.

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    Tanik, Nermin; Serin, Halil Ibrahim; Celikbilek, Asuman; Inan, Levent Ertugrul; Gundogdu, Fatma

    2015-11-15

    Multiple sclerosis (MS) is a neuroinflammatory and neurodegenerative disease that progresses to axonal loss and demyelinization. Olfactory dysfunction in patients with MS has been reported frequently. We were interested in the associations of olfactory bulb (OB) and olfactory sulcus depth (OSD) with disease duration and attack frequency. We included 25 patients with MS and 30 age- and sex-matched controls in this study. The Expanded Disability Status Scale, Beck Depression Inventory, and Mini Mental State Examination were applied. OB, OSD, and magnetic resonance imaging plaque numbers were calculated. OB volume and OSD in patients with MS were significantly lower than those in the control group (right and left OB: p<0.001; right OSD: p=0.001; and left OSD: p=0.039). Disease duration was negatively correlated with right and left OB volume (right OB: r=-0.434, p=0.030 and left OB: r=-0.518, p=0.008). Attack frequency was negatively correlated with left OB volume and left OSD (left OB: r=-0.428, p=0.033 and left OSD: r=-0.431, p=0.032). The OB and OSD were atrophied significantly in patients with MS, and this was correlated with disease duration and attack frequency. The left side tended to be dominant. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Evaluation of olfactory bulb size on MR imaging in normal volunteers and anosmic or hyposmic patients without nasal disease

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    Park, Jong Ho; Lee, Yul; Yoon, In Sook; Lee, Kyung Won; Yang, Ik; Chung, Soo Young; Yang, Kyung Hun

    1998-01-01

    The purpose of this study is to evaluate the size of the olfactory bulb using MRI in normal volunteers and anosmic or hyposmic patients without nasal diseases. MRI performed in 20 normal volunteers with a normal sense of smell, and in 15 anosmic or hyposmic or hyposmic patients without nasal disease but with abnormality in the olfactory function test. Coronal T1-weighted MRI was performed, with a section thickness of 3 mm. The cross sectional area, width and height of the olfactory bulb were measured in multiple sequential images and the largest values of these were analysed. The difference in the size of the olfactory bulb between normal volunteers and anosmic or hyposmic patients was evaluated and student''s test was used for statistical analysis. The size of the olfactory bulb is significantly less in anosmic or hyposmic patients without nasal disease than in normal volunteers; in such patients, olfactory MRI could be a useful evaluative modality. (author). 16 refs., 2 tabs., 4 figs

  6. Sensory-Evoked Intrinsic Imaging Signals in the Olfactory Bulb Are Independent of Neurovascular Coupling

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    Roberto Vincis

    2015-07-01

    Full Text Available Functional brain-imaging techniques used in humans and animals, such as functional MRI and intrinsic optical signal (IOS imaging, are thought to largely rely on neurovascular coupling and hemodynamic responses. Here, taking advantage of the well-described micro-architecture of the mouse olfactory bulb, we dissected the nature of odor-evoked IOSs. Using in vivo pharmacology in transgenic mouse lines reporting activity in different cell types, we show that parenchymal IOSs are largely independent of neurotransmitter release and neurovascular coupling. Furthermore, our results suggest that odor-evoked parenchymal IOSs originate from changes in light scattering of olfactory sensory neuron axons, mostly due to water movement following action potential propagation. Our study sheds light on a direct correlate of neuronal activity, which may be used for large-scale functional brain imaging.

  7. The olfactory bulb theta rhythm follows all frequencies of diaphragmatic respiration in the freely behaving rat

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    Daniel eRojas-Líbano

    2014-06-01

    Full Text Available Sensory-motor relationships are part of the normal operation of sensory systems. Sensing occurs in the context of active sensor movement, which in turn influences sensory processing. We address such a process in the rat olfactory system. Through recordings of the diaphragm electromyogram (EMG, we monitored the motor output of the respiratory circuit involved in sniffing behavior, simultaneously with the local field potential (LFP of the olfactory bulb (OB in rats moving freely in a familiar environment, where they display a wide range of respiratory frequencies. We show that the OB LFP represents the sniff cycle with high reliability at every sniff frequency and can therefore be used to study the neural representation of motor drive in a sensory cortex.

  8. Impaired mastication reduced newly generated neurons at the accessory olfactory bulb and pheromonal responses in mice.

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    Utsugi, Chizuru; Miyazono, Sadaharu; Osada, Kazumi; Matsuda, Mitsuyoshi; Kashiwayanagi, Makoto

    2014-12-01

    A large number of neurons are generated at the subventricular zone (SVZ) even during adulthood. In a previous study, we have shown that a reduced mastication impairs both neurogenesis in the SVZ and olfactory functions. Pheromonal signals, which are received by the vomeronasal organ, provide information about reproductive and social states. Vomeronasal sensory neurons project to the accessory olfactory bulb (AOB) located on the dorso-caudal surface of the main olfactory bulb. Newly generated neurons at the SVZ migrate to the AOB and differentiate into granule cells and periglomerular cells. This study aimed to explore the effects of changes in mastication on newly generated neurons and pheromonal responses. Bromodeoxyuridine-immunoreactive (BrdU-ir; a marker of DNA synthesis) and Fos-ir (a marker of neurons excited) structures in sagittal sections of the AOB after exposure to urinary odours were compared between the mice fed soft and hard diets. The density of BrdU-ir cells in the AOB in the soft-diet-fed mice after 1 month was essentially similar to that of the hard-diet-fed mice, while that was lower in the soft-diet-fed mice for 3 or 6 months than in the hard-diet-fed mice. The density of Fos-ir cells in the soft-diet-fed mice after 2 months was essentially similar to that in the hard-diet-fed mice, while that was lower in the soft-diet-fed mice for 4 months than in the hard-diet-fed mice. The present results suggest that impaired mastication reduces newly generated neurons at the AOB, which in turn impairs olfactory function at the AOB. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Newborn neurons in the olfactory bulb selected for long-term survival through olfactory learning are prematurely suppressed when the olfactory memory is erased.

    Science.gov (United States)

    Sultan, Sébastien; Rey, Nolwen; Sacquet, Joelle; Mandairon, Nathalie; Didier, Anne

    2011-10-19

    A role for newborn neurons in olfactory memory has been proposed based on learning-dependent modulation of olfactory bulb neurogenesis in adults. We hypothesized that if newborn neurons support memory, then they should be suppressed by memory erasure. Using an ecological approach in mice, we showed that behaviorally breaking a previously learned odor-reward association prematurely suppressed newborn neurons selected to survive during initial learning. Furthermore, intrabulbar infusions of the caspase pan-inhibitor ZVAD (benzyloxycarbonyl-Val-Ala-Asp) during the behavioral odor-reward extinction prevented newborn neurons death and erasure of the odor-reward association. Newborn neurons thus contribute to the bulbar network plasticity underlying long-term memory.

  10. Temporal Response Properties of Accessory Olfactory Bulb Neurons: Limitations and Opportunities for Decoding.

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    Yoles-Frenkel, Michal; Kahan, Anat; Ben-Shaul, Yoram

    2018-05-23

    The vomeronasal system (VNS) is a major vertebrate chemosensory system that functions in parallel to the main olfactory system (MOS). Despite many similarities, the two systems dramatically differ in the temporal domain. While MOS responses are governed by breathing and follow a subsecond temporal scale, VNS responses are uncoupled from breathing and evolve over seconds. This suggests that the contribution of response dynamics to stimulus information will differ between these systems. While temporal dynamics in the MOS are widely investigated, similar analyses in the accessory olfactory bulb (AOB) are lacking. Here, we have addressed this issue using controlled stimulus delivery to the vomeronasal organ of male and female mice. We first analyzed the temporal properties of AOB projection neurons and demonstrated that neurons display prolonged, variable, and neuron-specific characteristics. We then analyzed various decoding schemes using AOB population responses. We showed that compared with the simplest scheme (i.e., integration of spike counts over the entire response period), the division of this period into smaller temporal bins actually yields poorer decoding accuracy. However, optimal classification accuracy can be achieved well before the end of the response period by integrating spike counts within temporally defined windows. Since VNS stimulus uptake is variable, we analyzed decoding using limited information about stimulus uptake time, and showed that with enough neurons, such time-invariant decoding is feasible. Finally, we conducted simulations that demonstrated that, unlike the main olfactory bulb, the temporal features of AOB neurons disfavor decoding with high temporal accuracy, and, rather, support decoding without precise knowledge of stimulus uptake time. SIGNIFICANCE STATEMENT A key goal in sensory system research is to identify which metrics of neuronal activity are relevant for decoding stimulus features. Here, we describe the first systematic

  11. Neurodegenerative changes in the brainstem and olfactory bulb in people older than 50 years old: a descriptive study

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    Francine Hehn de Oliveira

    2015-07-01

    Full Text Available With the increase in life expectancy in Brazil, concerns have grown about the most prevalent diseases in elderly people. Among these diseases are neurodegenerative diseases, such as Alzheimer’s and Parkinson’s diseases. Protein deposits related to the development of these diseases can pre-date the symptomatic phases by years. The tau protein is particularly interesting: it might be found in the brainstem and olfactory bulb long before it reaches the limbic cortex, at which point symptoms occur. Of the 14 brains collected in this study, the tau protein was found in the brainstems of 10 (71.42% and in olfactory bulbs of 3 out 11. Of the 7 individuals who had a final diagnosis of Alzheimer’s disease (AD, 6 presented tau deposits in some region of the brainstem. Our data support the idea of the presence of tau protein in the brainstem and olfactory bulb in the earliest stages of AD.

  12. Neurogenesis in the olfactory bulb induced by paced mating in the female rat is opioid dependent.

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    Marianela Santoyo-Zedillo

    Full Text Available The possibility to control the rate of sexual stimulation that the female rat receives during a mating encounter (pacing increases the number of newborn neurons that reach the granular layer of the accessory olfactory bulb (AOB. If females mate repeatedly, the increase in the number of neurons is observed in other regions of the AOB and in the main olfactory bulb (MOB. It has also been shown that paced mating induces a reward state mediated by opioids. There is also evidence that opioids modulate neurogenesis. In the present study, we evaluated whether the opioid receptor antagonist naloxone (NX could reduce the increase in neurogenesis in the AOB induced by paced mating. Ovariectomized female rats were randomly divided in 5 different groups: 1 Control (not mated treated with saline, 2 control (not mated treated with naloxone, 3 females that mated without controlling the sexual interaction (no-pacing, 4 females injected with saline before pacing the sexual interaction and 5 females injected with NX before a paced mating session. We found, as previously described, that paced mating induced a higher number of new cells in the granular layer of the AOB. The administration of NX before paced mating, blocked the increase in the number of newborn cells and prevented these cells from differentiating into neurons. These data suggest that opioid peptides play a fundamental role in the neurogenesis induced by paced mating in female rats.

  13. The Effect of Chronic Methamphetamine Exposure on the Hippocampal and Olfactory Bulb Neuroproteomes of Rats.

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    Rui Zhu

    Full Text Available Nowadays, drug abuse and addiction are serious public health problems in the USA. Methamphetamine (METH is one of the most abused drugs and is known to cause brain damage after repeated exposure. In this paper, we conducted a neuroproteomic study to evaluate METH-induced brain protein dynamics, following a two-week chronic regimen of an escalating dose of METH exposure. Proteins were extracted from rat brain hippocampal and olfactory bulb tissues and subjected to liquid chromatography-mass spectrometry (LC-MS/MS analysis. Both shotgun and targeted proteomic analysis were performed. Protein quantification was initially based on comparing the spectral counts between METH exposed animals and their control counterparts. Quantitative differences were further confirmed through multiple reaction monitoring (MRM LC-MS/MS experiments. According to the quantitative results, the expression of 18 proteins (11 in the hippocampus and 7 in the olfactory bulb underwent a significant alteration as a result of exposing rats to METH. 13 of these proteins were up-regulated after METH exposure while 5 were down-regulated. The altered proteins belonging to different structural and functional families were involved in processes such as cell death, inflammation, oxidation, and apoptosis.

  14. Imaging of olfactory bulb and gray matter volumes in brain areas associated with olfactory function in patients with Parkinson's disease and multiple system atrophy

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    Chen, Shun, E-mail: shchen_2013@163.com [Department of Neurology, The First Affiliated Hospital of Guangzhou Medical College (China); Tan, Hong-yu, E-mail: honhyutan@21cn.com [Department of Neurology, The First Affiliated Hospital of Guangzhou Medical College (China); Wu, Zhuo-hua, E-mail: zhh88@126.com [Department of Neurology, The First Affiliated Hospital of Guangzhou Medical College (China); Sun, Chong-peng, E-mail: Suncp2002@gmail.com [Imaging Center, The First Affiliated Hospital of Guangzhou Medical College (China); He, Jian-xun, E-mail: xundog@163.com [Imaging Center, The First Affiliated Hospital of Guangzhou Medical College (China); Li, Xin-chun, E-mail: xinchunli@163.com [Imaging Center, The First Affiliated Hospital of Guangzhou Medical College (China); Shao, Ming, E-mail: yimshao@126.com [Department of Neurology, The First Affiliated Hospital of Guangzhou Medical College (China)

    2014-03-15

    We explored if magnetic resonance imaging sequences might aid in the clinical differential diagnosis of idiopathic Parkinson's disease (IPD) and multiple system atrophy (MSA). We measured the volumes of the olfactory bulb, the olfactory tract, and olfaction-associated cortical gray matter in 20 IPD patients, 14 MSA patients, and 12 normal subjects, using high-resolution magnetic resonance imaging sequences in combination with voxel-based statistical analysis. We found that, compared to normal subjects and MSA patients, the volumes of the olfactory bulb and tract were significantly reduced in IPD patients. The gray matter volume of IPD patients decreased in the following order: the olfactory area to the right of the piriform cortex, the right amygdala, the left entorhinal cortex, and the left occipital lobe. Further, the total olfactory bulb volume of IPD patients was associated with the duration of disease. The entorhinal cortical gray matter volume was negatively associated with the UPDRS III score. Conclusion: Structural volumes measured by high-resolution magnetic resonance imaging may potentially be used for differential diagnosis of IPD from MSA.

  15. Imaging of olfactory bulb and gray matter volumes in brain areas associated with olfactory function in patients with Parkinson's disease and multiple system atrophy

    International Nuclear Information System (INIS)

    Chen, Shun; Tan, Hong-yu; Wu, Zhuo-hua; Sun, Chong-peng; He, Jian-xun; Li, Xin-chun; Shao, Ming

    2014-01-01

    We explored if magnetic resonance imaging sequences might aid in the clinical differential diagnosis of idiopathic Parkinson's disease (IPD) and multiple system atrophy (MSA). We measured the volumes of the olfactory bulb, the olfactory tract, and olfaction-associated cortical gray matter in 20 IPD patients, 14 MSA patients, and 12 normal subjects, using high-resolution magnetic resonance imaging sequences in combination with voxel-based statistical analysis. We found that, compared to normal subjects and MSA patients, the volumes of the olfactory bulb and tract were significantly reduced in IPD patients. The gray matter volume of IPD patients decreased in the following order: the olfactory area to the right of the piriform cortex, the right amygdala, the left entorhinal cortex, and the left occipital lobe. Further, the total olfactory bulb volume of IPD patients was associated with the duration of disease. The entorhinal cortical gray matter volume was negatively associated with the UPDRS III score. Conclusion: Structural volumes measured by high-resolution magnetic resonance imaging may potentially be used for differential diagnosis of IPD from MSA

  16. Statistical analysis of coding for molecular properties in the olfactory bulb

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    Benjamin eAuffarth

    2011-07-01

    Full Text Available The relationship between molecular properties of odorants and neural activities is arguably one of the most important issues in olfaction and the rules governing this relationship are still not clear. In the olfactory bulb (OB, glomeruli relay olfactory information to second-order neurons which in turn project to cortical areas. We investigate relevance of odorant properties, spatial localization of glomerular coding sites, and size of coding zones in a dataset of 2-deoxyglucose images of glomeruli over the entire OB of the rat. We relate molecular properties to activation of glomeruli in the OB using a nonparametric statistical test and a support-vector machine classification study. Our method permits to systematically map the topographic representation of various classes of odorants in the OB. Our results suggest many localized coding sites for particular molecular properties and some molecular properties that could form the basis for a spatial map of olfactory information. We found that alkynes, alkanes, alkenes, and amines affect activation maps very strongly as compared to other properties and that amines, sulfur-containing compounds, and alkynes have small zones and high relevance to activation changes, while aromatics, alkanes, and carboxylics acid recruit very big zones in the dataset. Results suggest a local spatial encoding for molecular properties.

  17. The functional significance of newly born neurons integrated into olfactory bulb circuits.

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    Sakamoto, Masayuki; Kageyama, Ryoichiro; Imayoshi, Itaru

    2014-01-01

    The olfactory bulb (OB) is the first central processing center for olfactory information connecting with higher areas in the brain, and this neuronal circuitry mediates a variety of odor-evoked behavioral responses. In the adult mammalian brain, continuous neurogenesis occurs in two restricted regions, the subventricular zone (SVZ) of the lateral ventricle and the hippocampal dentate gyrus. New neurons born in the SVZ migrate through the rostral migratory stream and are integrated into the neuronal circuits of the OB throughout life. The significance of this continuous supply of new neurons in the OB has been implicated in plasticity and memory regulation. Two decades of huge investigation in adult neurogenesis revealed the biological importance of integration of new neurons into the olfactory circuits. In this review, we highlight the recent findings about the physiological functions of newly generated neurons in rodent OB circuits and then discuss the contribution of neurogenesis in the brain function. Finally, we introduce cutting edge technologies to monitor and manipulate the activity of new neurons.

  18. The functional significance of newly born neurons integrated into olfactory bulb circuits

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    Masayuki eSakamoto

    2014-05-01

    Full Text Available The olfactory bulb (OB is the first central processing center for olfactory information connecting with higher areas in the brain, and this neuronal circuitry mediates a variety of odor-evoked behavioral responses. In the adult mammalian brain, continuous neurogenesis occurs in two restricted regions, the subventricular zone (SVZ of the lateral ventricle and the hippocampal dentate gyrus. New neurons born in the SVZ migrate through the rostral migratory stream and are integrated into the neuronal circuits of the OB throughout life. The significance of this continuous supply of new neurons in the OB has been implicated in plasticity and memory regulation. Two decades of huge investigation in adult neurogenesis revealed the biological importance of integration of new neurons into the olfactory circuits. In this review, we highlight the recent findings about the physiological functions of newly generated neurons in rodent OB circuits and then discuss the contribution of neurogenesis in the brain function. Finally, we introduce cutting edge technologies to monitor and manipulate the activity of new neurons.

  19. Novel subdomains of the mouse olfactory bulb defined by molecular heterogeneity in the nascent external plexiform and glomerular layers

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    Yona Golan

    2007-05-01

    Full Text Available Abstract Background In the mouse olfactory system, the role of the olfactory bulb in guiding olfactory sensory neuron (OSN axons to their targets is poorly understood. What cell types within the bulb are necessary for targeting is unknown. What genes are important for this process is also unknown. Although projection neurons are not required, other cell-types within the external plexiform and glomerular layers also form synapses with OSNs. We hypothesized that these cells are important for targeting, and express spatially differentially expressed guidance cues that act to guide OSN axons within the bulb. Results We used laser microdissection and microarray analysis to find genes that are differentially expressed along the dorsal-ventral, medial-lateral, and anterior-posterior axes of the bulb. The expression patterns of these genes divide the bulb into previously unrecognized subdomains. Interestingly, some genes are expressed in both the medial and lateral bulb, showing for the first time the existence of symmetric expression along this axis. We use a regeneration paradigm to show that several of these genes are altered in expression in response to deafferentation, consistent with the interpretation that they are expressed in cells that interact with OSNs. Conclusion We demonstrate that the nascent external plexiform and glomerular layers of the bulb can be divided into multiple domains based on the expression of these genes, several of which are known to function in axon guidance, synaptogenesis, and angiogenesis. These genes represent candidate guidance cues that may act to guide OSN axons within the bulb during targeting.

  20. The Role of Astrocytes in the Generation, Migration, and Integration of New Neurons in the Adult Olfactory Bulb

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    Gengatharan, Archana; Bammann, Rodrigo R.; Saghatelyan, Armen

    2016-01-01

    In mammals, new neurons in the adult olfactory bulb originate from a pool of neural stem cells in the subventricular zone of the lateral ventricles. Adult-born cells play an important role in odor information processing by adjusting the neuronal network to changing environmental conditions. Olfactory bulb neurogenesis is supported by several non-neuronal cells. In this review, we focus on the role of astroglial cells in the generation, migration, integration, and survival of new neurons in the adult forebrain. In the subventricular zone, neural stem cells with astrocytic properties display regional and temporal specificity when generating different neuronal subtypes. Non-neurogenic astrocytes contribute to the establishment and maintenance of the neurogenic niche. Neuroblast chains migrate through the rostral migratory stream ensheathed by astrocytic processes. Astrocytes play an important regulatory role in neuroblast migration and also assist in the development of a vasculature scaffold in the migratory stream that is essential for neuroblast migration in the postnatal brain. In the olfactory bulb, astrocytes help to modulate the network through a complex release of cytokines, regulate blood flow, and provide metabolic support, which may promote the integration and survival of new neurons. Astrocytes thus play a pivotal role in various processes of adult olfactory bulb neurogenesis, and it is likely that many other functions of these glial cells will emerge in the near future. PMID:27092050

  1. Transcriptome profile and cytogenetic analysis of immortalized neuronally restricted progenitor cells derived from the porcine olfactory bulb

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    Recently, we established and phenotypically characterized an immortalized porcine olfactory bulb neuroblast cell line, OBGF400 (Uebing-Czipura et al., 2008). To facilitate the future application of these cells in studies of neurological dysfunction and neuronal replacement therapies, a comprehensive...

  2. Localisation of 3H-GABA in the rat olfactory bulb: An in vivo and in vitro autoradiographic study

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    Jaffe, E.H.; Cuello, A.C.; Priestley, J.V.

    1983-01-01

    In an attempt to further clarify the localisation of GABAergic elements in the olfactory bulb we have performed, in vivo and in vitro, autoradiographic studies with 3 H-GABA (#betta#-amino butyric acid) and 3 H-DABA (L-2,4 diamino butyric acid). The results have shown a strong labelling with 3 H-GABA of the glial cells in all the layers of the olfactory bulb. A high concentration of grains was observed in the periglomerular region. The labelling in the external plexiform layer was uniformly distributed in the neuropile with the strongest activity at the level of the dendritic processes of the granule cells, leaving the mitral cell dendrites and cell bodies almost free of grains. 3 H-DABA showed a very similar pattern to 3 H-GABA. When olfactory bulb slices were preincubated with #betta#-alanine the labelling of the glial elements almost disappeared especially at the level of the olfactory nerve layer. The labelling pattern of the other layers of the bulb remained mostly unchanged. This supports the view that a population of periglomerular and granule cells are GABAergic and that #betta#-alanine competes with GABA uptake sites only in glial cells. (orig.)

  3. Amyloid beta inhibits olfactory bulb activity and the ability to smell.

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    Reynaldo Alvarado-Martínez

    Full Text Available Early olfactory dysfunction has been consistently reported in both Alzheimer's disease (AD and in transgenic mice that reproduce some features of this disease. In AD transgenic mice, alteration in olfaction has been associated with increased levels of soluble amyloid beta protein (Aβ as well as with alterations in the oscillatory network activity recorded in the olfactory bulb (OB and in the piriform cortex. However, since AD is a multifactorial disease and transgenic mice suffer a variety of adaptive changes, it is still unknown if soluble Aβ, by itself, is responsible for OB dysfunction both at electrophysiological and behavioral levels. Thus, here we tested whether or not Aβ directly affects OB network activity in vitro in slices obtained from mice and rats and if it affects olfactory ability in these rodents. Our results show that Aβ decreases, in a concentration- and time-dependent manner, the network activity of OB slices at clinically relevant concentrations (low nM and in a reversible manner. Moreover, we found that intrabulbar injection of Aβ decreases the olfactory ability of rodents two weeks after application, an effect that is not related to alterations in motor performance or motivation to seek food and that correlates with the presence of Aβ deposits. Our results indicate that Aβ disrupts, at clinically relevant concentrations, the network activity of the OB in vitro and can trigger a disruption in olfaction. These findings open the possibility of exploring the cellular mechanisms involved in early pathological AD as an approach to reduce or halt its progress.

  4. Physical limits to autofluorescence signals in vivo recordings in the rat olfactory bulb: a Monte Carlo study

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    L'Heureux, B.; Gurden, H.; Pinot, L.; Mastrippolito, R.; Lefebvre, F.; Lanièce, P.; Pain, F.

    2007-07-01

    Understanding the cellular mechanisms of energy supply to neurons following physiological activation is still challenging and has strong implications to the interpretation of clinical functional images based on metabolic signals such as Blood Oxygen Level Dependent Magnetic Resonance Imaging or 18F-Fluorodexoy-Glucose Positron Emission Tomography. Intrinsic Optical Signal Imaging provides with high spatio temporal resolution in vivo imaging in the anaesthetized rat. In that context, intrinsic signals are mainly related to changes in the optical absorption of haemoglobin depending on its oxygenation state. This technique has been validated for imaging of the rat olfactory bulb, providing with maps of the actived olfactory glomeruli, the functional modules involved in the first step of olfactory coding. A complementary approach would be autofluorescence imaging relying on the fluorescence properties of endogenous Flavin Adenine Dinucleotide (FAD) or Nicotinamide Adenine Dinucleotide (NADH) both involved in intracellular metabolic pathways. The purpose of the present study was to investigate the feasibility of in vivo autofluorescence imaging in the rat olfactory bulb. We performed standard Monte Carlo simulations of photons scattering and absorption at the excitation and emission wavelengths of FAD and NADH fluorescence. Characterization of the fluorescence distribution in the glomerulus, effect of hemoglobin absorption at the excitation and absorption wavelengths as well as the effect of the blurring due to photon scattering and the depth of focus of the optical apparatus have been studied. Finally, optimal experimental parameters are proposed to achieve in vivo validation of the technique in the rat olfactory bulb.

  5. Olfactory bulb dysgenesis, mirror neuron system dysfunction, and autonomic dysregulation as the neural basis for autism.

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    Brang, David; Ramachandran, V S

    2010-05-01

    Autism is a disorder characterized by social withdrawal, impoverished language and empathy, and a profound inability to adopt another's viewpoint - a failure to construct a "theory of mind" for interpreting another person's thoughts and intentions. We previously showed that these symptoms might be explained, in part, by a paucity of mirror neurons. Prompted by an MRI report of an individual with autism, we now suggest that there may be, in addition, a congenital aplasia/dysplasia of the olfactory bulbs with consequent reduction of vasopressin and oxytocin receptor binding. There may also be sub-clinical temporal lobe epilepsy affecting the recently discovered third visual system that is rich in "empathy" related mirror neurons (MNS) and projects (via the TOP junction - just below the inferior parietal lobule) to limbic structures that regulate autonomic outflow. This causes deranged autonomic feedback, resulting in additional deficiencies in MNS with loss of emotional empathy and introspection.

  6. Age and gender-related differences in mitral cells of olfactory bulb

    International Nuclear Information System (INIS)

    Haq, I.H.; Tahir, M.

    2008-01-01

    To investigate the age and gender-related differences in mitral cells of the human cadaveric olfactory bulbs. Sixty olfactory bulbs, 30 each from male and female (age 20-76 years) human cadavers divided into six groups of age and gender-wise were collected from the mortuary of the King Edward Medical University, Lahore. Mitral cells were counted and their diameter was calculated from 10 micro m thick cresyl violet stained histological sections. Statistical analysis was done using ANOVA for age-related differences and independent t-test for gender-related differences. There was significant reduction in the number of mitral cells and diameter of their nuclei with age. There was significant decrease in the number of mitral cells in males, between groups I and II (p < 0.001); II and III (p < 0.001); and I and III (p < 0.001); statistically significant decrease also occurred in females, between groups IV and V (p < 0.001); V and VI (p < 0.001); and IV and VI (p < 0.001). In most cases, the distance between individual mitral cells was seen to be much greater than in younger group. In group VI, few mitral cells were observed in the cell layer. There was also significant decrease in the diameter of mitral cell nuclei in males, between groups I and III (p < 0.001); and II and III (p < 0.010); in females, between groups IV and VI (p < 0.001); and V and VI (p < 0.001). No gender-related differences were observed. The number of mitral cells and diameter of their nuclei decreased with advancing age. (author)

  7. Sexual activity increases the number of newborn cells in the accessory olfactory bulb of male rats.

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    Wendy ePortillo

    2012-07-01

    Full Text Available In rodents, sexual behavior depends on the adequate detection of sexually relevant stimuli. The olfactory bulb (OB is a region of the adult mammalian brain undergoing constant cell renewal by continuous integration of new granular and periglomerular neurons in the accessory (AOB and main (MOB olfactory bulbs. The proliferation, migration, survival, maturation, and integration of these new cells to the OB depend on the stimulus that the subjects received. We have previously shown that 15 days after females control (paced the sexual interaction an increase in the number of cells is observed in the AOB. No changes are observed in the number of cells when females are not allowed to control the sexual interaction. In the present study we investigated if in male rats sexual behavior increases the number of new cells in the OB. Male rats were divided in five groups: 1 males that did not receive any sexual stimulation, 2 males that were exposed to female odors, 3 males that mated for 1 h and could not pace their sexual interaction, 4 males that paced their sexual interaction and ejaculated 1 time and 5 males that paced their sexual interaction and ejaculated 3 times. All males received three injections of the DNA synthesis marker bromodeoxyuridine at 1h intervals, starting 1h before the beginning of the behavioral test. Fifteen days later, males were sacrificed and the brains were processed to identify new cells and to evaluate if they differentiated into neurons. The number of newborn cells increased in the granular cell layer (also known as the internal cell layer of the AOB in males that ejaculated one or three times controlling (paced the rate of the sexual interaction. Some of these new cells were identified as neurons. In contrast, no significant differences were found in the mitral cell layer (also known as the external cell layer and glomerular cell layer of the AOB. In addition, no significant differences were found between groups in the MOB in

  8. The Stem Cell Marker Lgr5 Defines a Subset of Postmitotic Neurons in the Olfactory Bulb.

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    Yu, Yiqun; Moberly, Andrew H; Bhattarai, Janardhan P; Duan, Chen; Zheng, Qian; Li, Fangqi; Huang, Hugh; Olson, William; Luo, Wenqin; Wen, Tieqiao; Yu, Hongmeng; Ma, Minghong

    2017-09-27

    Lgr5, leucine-rich repeat-containing G-protein coupled receptor 5, is a bona fide biomarker for stem cells in multiple tissues. Lgr5 is also expressed in the brain, but the identities and properties of these Lgr5 + cells are still elusive. Using an Lgr5-EGFP reporter mouse line, we found that, from early development to adulthood, Lgr5 is highly expressed in the olfactory bulb (OB), an area with ongoing neurogenesis. Immunostaining with stem cell, glial, and neuronal markers reveals that Lgr5 does not label stem cells in the OB but instead labels a heterogeneous population of neurons with preference in certain subtypes. Patch-clamp recordings in OB slices reveal that Lgr5-EGFP + cells fire action potentials and display spontaneous excitatory postsynaptic events, indicating that these neurons are integrated into OB circuits. Interestingly, R-spondin 3, a potential ligand of Lgr5, is also expressed in the adult OB. Collectively, our data indicate that Lgr5-expressing cells in the OB are fully differentiated neurons and imply distinct roles of Lgr5 and its ligand in postmitotic cells. SIGNIFICANCE STATEMENT Lgr5 (leucine-rich repeat-containing G-protein coupled receptor 5) is a bona fide stem cell marker in many body organs. Here we report that Lgr5 is also highly expressed in the olfactory bulb (OB), the first relay station in the brain for processing odor information and one of the few neural structures that undergo continuous neurogenesis. Surprisingly, Lgr5 is not expressed in the OB stem cells, but instead in a few subtypes of terminally differentiated neurons, which are incorporated into the OB circuit. This study reveals that Lgr5 + cells in the brain represent a nonstem cell lineage, implying distinct roles of Lgr5 in postmitotic neurons. Copyright © 2017 the authors 0270-6474/17/379403-12$15.00/0.

  9. Medullary neurons in the core white matter of the olfactory bulb: a new cell type.

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    Paredes, Raúl G; Larriva-Sahd, Jorge

    2010-02-01

    The structure of a new cell type, termed the medullary neuron (MN) because of its intimate association with the rostral migratory stream (RMS) in the bulbar core, is described in the adult rat olfactory bulb. The MN is a triangular or polygonal interneuron whose soma lies between the cellular clusters of the RMS or, less frequently, among the neuron progenitors therein. MNs are easily distinguished from adjacent cells by their large size and differentiated structure. Two MN subtypes have been categorized by the Golgi technique: spiny pyramidal neurons and aspiny neurons. Both MN subtypes bear a large dendritic field impinged upon by axons in the core bulbar white matter. A set of collaterals from the adjacent axons appears to terminate on the MN dendrites. The MN axon passes in close apposition to adjacent neuron progenitors in the RMS. MNs are immunoreactive with antisera raised against gamma-aminobutyric acid and glutamate decarboxylase 65/67. Electron-microscopic observations confirm that MNs correspond to fully differentiated, mature neurons. MNs seem to be highly conserved among macrosmatic species as they occur in Nissl-stained brain sections from mouse, guinea pig, and hedgehog. Although the functional role of MNs remains to be determined, we suggest that MNs represent a cellular interface between endogenous olfactory activity and the differentiation of new neurons generated during adulthood.

  10. Cholinergic Inputs from Basal Forebrain Add an Excitatory Bias to Odor Coding in the Olfactory Bulb

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    Rothermel, Markus; Carey, Ryan M.; Puche, Adam; Shipley, Michael T.

    2014-01-01

    Cholinergic modulation of central circuits is associated with active sensation, attention, and learning, yet the neural circuits and temporal dynamics underlying cholinergic effects on sensory processing remain unclear. Understanding the effects of cholinergic modulation on particular circuits is complicated by the widespread projections of cholinergic neurons to telencephalic structures that themselves are highly interconnected. Here we examined how cholinergic projections from basal forebrain to the olfactory bulb (OB) modulate output from the first stage of sensory processing in the mouse olfactory system. By optogenetically activating their axons directly in the OB, we found that cholinergic projections from basal forebrain regulate OB output by increasing the spike output of presumptive mitral/tufted cells. Cholinergic stimulation increased mitral/tufted cell spiking in the absence of inhalation-driven sensory input and further increased spiking responses to inhalation of odorless air and to odorants. This modulation was rapid and transient, was dependent on local cholinergic signaling in the OB, and differed from modulation by optogenetic activation of cholinergic neurons in basal forebrain, which led to a mixture of mitral/tufted cell excitation and suppression. Finally, bulbar cholinergic enhancement of mitral/tufted cell odorant responses was robust and occurred independent of the strength or even polarity of the odorant-evoked response, indicating that cholinergic modulation adds an excitatory bias to mitral/tufted cells as opposed to increasing response gain or sharpening response spectra. These results are consistent with a role for the basal forebrain cholinergic system in dynamically regulating the sensitivity to or salience of odors during active sensing of the olfactory environment. PMID:24672011

  11. Dendritic branching of olfactory bulb mitral and tufted cells: regulation by TrkB.

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    Fumiaki Imamura

    2009-08-01

    Full Text Available Projection neurons of mammalian olfactory bulb (OB, mitral and tufted cells, have dendrites whose morphologies are specifically differentiated for efficient odor information processing. The apical dendrite extends radially and arborizes in single glomerulus where it receives primary input from olfactory sensory neurons that express the same odor receptor. The lateral dendrites extend horizontally in the external plexiform layer and make reciprocal dendrodendritic synapses with granule cells, which moderate mitral/tufted cell activity. The molecular mechanisms regulating dendritic development of mitral/tufted cells is one of the unsolved important problems in the olfactory system. Here, we focused on TrkB receptors to test the hypothesis that neurotrophin-mediate mechanisms contributed to dendritic differentiation of OB mitral/tufted cells.With immunohistochemical analysis, we found that the TrkB neurotrophin receptor is expressed by both apical and lateral dendrites of mitral/tufted cells and that expression is evident during the early postnatal days when these dendrites exhibit their most robust growth and differentiation. To examine the effect of TrkB activation on mitral/tufted cell dendritic development, we cultured OB neurons. When BDNF or NT4 were introduced into the cultures, there was a significant increase in the number of primary neurites and branching points among the mitral/tufted cells. Moreover, BDNF facilitated filopodial extension along the neurites of mitral/tufted cells.In this report, we show for the first time that TrkB activation stimulates the dendritic branching of mitral/tufted cells in developing OB. This suggests that arborization of the apical dendrite in a glomerulus is under the tight regulation of TrkB activation.

  12. Mapping of odor-related neuronal activity in the olfactory bulb by high-resolution 2-deoxyglucose autoradiography

    International Nuclear Information System (INIS)

    Lancet, D.; Greer, C.A.; Kauer, J.S.; Shepherd, G.M.

    1982-01-01

    The spatial distribution of odor-induced neuronal activity in the olfactory bulb, the first relay station of the olfactory pathway, is believed to reflect important aspects of chemosensory coding. We report here the application of high-resolution 2-deoxyglucose autoradiography to the mapping of spatial patterns of metabolic activity at the level of single neurons in the olfactory bulb. It was found that glomeruli, which are synaptic complexes containing the first synaptic relay, tend to be uniformly active or inactive during odor exposure. Differential 2-deoxyglucose uptake was also observed in the somata of projection neurons (mitral cells) and interneurons (periglomerular and granule cells). This confirms and extends our previous studies in which odor-specific laminar and focal uptake patterns were revealed by the conventional x-ray film 2-deoxyglucose method due to Sokoloff and colleagues [Sokoloff, L., Reivich, M., Kennedy, C., DesRosiers, M. H., Patlak, C. S., Pettigrew, K. D., Sakurada, O. and Shinohara, M. (1977) J. Neurochem. 28, 897-916]. Based on results obtained by the two methods, it is suggested that the glomerulus as a whole serves as a functional unit of activity. The high-resolution results are interpreted in terms of the well-characterized synaptic organization of the olfactory bulb and also serve to illustrate the capability of the 2-deoxyglucose autoradiographic technique to map metabolic activity in single neurons of the vertebrate central nervous system

  13. Accumulation and turnover of metabolites of toluene and xylene in nasal mucosa and olfactory bulb in the mouse

    International Nuclear Information System (INIS)

    Ghantous, H.; Dencker, L.; Danielsson, B.R.G; Gabrielsson, J.; Bergman, K.

    1990-01-01

    Autoradiography of male mice following inhalation of the radioactively labelled solvents, toluene, xylene, and styrene, revealed an accumulation of non-volatile metabolites in the nasal mucosa and olfactory bulb of the brain. Since no accumulation occurred after benzene inhalation, it was assumed that the activity represented aromatic acids, which are known metabolites of these solvents. This was supported by the finding that also radioactive benzoic acid (main metabolite of toluene) and salicylic acid accumulated in the olfactory bulb. High-performance liquid chromatography revealed that after toluene inhalation (for 1 hr), nasal mucosa and olfactory bulb contained mainly benzoic acid, with a strong accumulation in relation to blood plasma, and considerably less of its blycine conjugate, hippuric acid. After xylene inhalation, on the other hand, methyl hippuric acid dominated over the non-conjugated metabolite, toluic acid. The results indicate a specific, possibly axonal flow-mediated transport of aromatic acids from the nasal mucosa to the olfactory lobe of the brain. The toxicological significance of these results remains to be studied. (author)

  14. Dopaminergic modulation of mitral cell activity in the frog olfactory bulb: a combined radioligand binding-electrophysiological study

    International Nuclear Information System (INIS)

    Duchamp, A.; Moyse, E.; Delaleu, J.-C.; Coronas, V.; Duchamp-Viret, P.

    1997-01-01

    Dopamine content in the amphibian olfactory bulb is supplied by interneurons scattered among mitral cells in the external plexiform/mitral cell layer. In mammals, dopamine has been found to be involved in various aspects of bulbar information processing by influencing mitral cell odour responsiveness. Dopamine action in the bulb depends directly on the localization of its receptor targets, found to be mainly of the D 2 type in mammals. The present study assessed, in the frog, both the anatomical localization of D 2 -like, radioligand-labelled receptors of dopamine and the in vivo action of dopamine on unitary mitral cell activity in response to odours delivered over a wide range of concentrations. The [ 125 I]iodosulpride-labelled D 2 binding sites were visualized on frozen sagittal sections of frog brains by film radioautography. The sites were found to be restricted to the external plexiform/mitral cell layer; other layers of the olfactory bulb were devoid of specific labelling. Electrophysiological recordings of mitral unit activity revealed that dopamine or its agonist apomorphine induced a drastic reduction of spontaneous firing rate of mitral cells in most cases without altering odour intensity coding properties of these cells. Moreover, pre-treatment with the D 2 antagonist eticlopride blocked the dopamine-induced reduction of mitral cell spontaneous activity.In the frog olfactory bulb, both anatomical localization of D 2 -like receptors and functional data on dopamine involvement in information processing differ from those reported in mammals. This suggests a phylogenetic evolution of dopamine action in the olfactory bulb. In the frog, anatomical data perfectly corroborate electrophysiological results, together strongly suggesting a direct action of dopamine on mitral cells. In a physiologically operating system, such an action would result in a global improvement of signal-to-noise ratio. (Copyright (c) 1997 Elsevier Science B.V., Amsterdam. All rights

  15. Rasagiline ameliorates olfactory deficits in an alpha-synuclein mouse model of Parkinson's disease.

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    Géraldine H Petit

    Full Text Available Impaired olfaction is an early pre-motor symptom of Parkinson's disease. The neuropathology underlying olfactory dysfunction in Parkinson's disease is unknown, however α-synuclein accumulation/aggregation and altered neurogenesis might play a role. We characterized olfactory deficits in a transgenic mouse model of Parkinson's disease expressing human wild-type α-synuclein under the control of the mouse α-synuclein promoter. Preliminary clinical observations suggest that rasagiline, a monoamine oxidase-B inhibitor, improves olfaction in Parkinson's disease. We therefore examined whether rasagiline ameliorates olfactory deficits in this Parkinson's disease model and investigated the role of olfactory bulb neurogenesis. α-Synuclein mice were progressively impaired in their ability to detect odors, to discriminate between odors, and exhibited alterations in short-term olfactory memory. Rasagiline treatment rescued odor detection and odor discrimination abilities. However, rasagiline did not affect short-term olfactory memory. Finally, olfactory changes were not coupled to alterations in olfactory bulb neurogenesis. We conclude that rasagiline reverses select olfactory deficits in a transgenic mouse model of Parkinson's disease. The findings correlate with preliminary clinical observations suggesting that rasagiline ameliorates olfactory deficits in Parkinson's disease.

  16. Cellular and molecular cues of glucose sensing in the rat olfactory bulb

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    Dolly eAl Koborssy

    2014-10-01

    Full Text Available In the brain, glucose homeostasis of extracellular fluid is crucial to the point that systems specifically dedicated to glucose sensing are found in areas involved in energy regulation and feeding behavior. Olfaction is a major sensory modality regulating food consumption. Nutritional status in turn modulates olfactory detection. Recently it has been proposed that some olfactory bulb (OB neurons respond to glucose similarly to hypothalamic neurons. However, the precise molecular cues governing glucose sensing in the OB are largely unknown. To decrypt these molecular mechanisms, we first used immunostaining to demonstrate a strong expression of two neuronal markers of glucose-sensitivity, insulin-dependent glucose transporter type 4 (GLUT4, and sodium glucose co-transporter type 1 (SGLT1 in specific OB layers. We showed that expression and mapping of GLUT4 but not SGLT1 were feeding state-dependent. In order to investigate the impact of metabolic status on the delivery of blood-borne glucose to the OB, we measured extracellular fluid glucose concentration using glucose biosensors simultaneously in the OB and cortex of anesthetized rats. We showed that glucose concentration in the OB is higher than in the cortex, that metabolic steady-state glucose concentration is independent of feeding state in the two brain areas, and that acute changes in glycemic conditions affect bulbar glucose concentration alone. These data provide new evidence of a direct relationship between the OB and peripheral metabolism, and emphasize the importance of glucose for the OB network, providing strong arguments toward establishing the OB as a glucose-sensing organ.

  17. Glomerular and Mitral-Granule Cell Microcircuits Coordinate Temporal and Spatial Information Processing in the Olfactory Bulb.

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    Cavarretta, Francesco; Marasco, Addolorata; Hines, Michael L; Shepherd, Gordon M; Migliore, Michele

    2016-01-01

    The olfactory bulb processes inputs from olfactory receptor neurons (ORNs) through two levels: the glomerular layer at the site of input, and the granule cell level at the site of output to the olfactory cortex. The sequence of action of these two levels has not yet been examined. We analyze this issue using a novel computational framework that is scaled up, in three-dimensions (3D), with realistic representations of the interactions between layers, activated by simulated natural odors, and constrained by experimental and theoretical analyses. We suggest that the postulated functions of glomerular circuits have as their primary role transforming a complex and disorganized input into a contrast-enhanced and normalized representation, but cannot provide for synchronization of the distributed glomerular outputs. By contrast, at the granule cell layer, the dendrodendritic interactions mediate temporal decorrelation, which we show is dependent on the preceding contrast enhancement by the glomerular layer. The results provide the first insights into the successive operations in the olfactory bulb, and demonstrate the significance of the modular organization around glomeruli. This layered organization is especially important for natural odor inputs, because they activate many overlapping glomeruli.

  18. Glomerular and mitral-granule cell microcircuits coordinate temporal and spatial information processing in the olfactory bulb

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    Francesco Cavarretta

    2016-07-01

    Full Text Available The olfactory bulb processes inputs from olfactory receptor neurons (ORNs through two levels: the glomerular layer at the site of input, and the granule cell level at the site of output to the olfactory cortex. The sequence of action of these two levels has not yet been examined. We analyze this issue using a novel computational framework that is scaled up, in three-dimensions (3D, with realistic representations of the interactions between layers, activated by simulated natural odors, and constrained by experimental and theoretical analyses. We suggest that the postulated functions of glomerular circuits have as their primary role transforming a complex and disorganized input into a contrast-enhanced and normalized representation, but cannot provide for synchronization of the distributed glomerular outputs. By contrast, at the granule cell layer, the dendrodendritic interactions mediate temporal decorrelation, which we show is dependent on the preceding contrast enhancement by the glomerular layer. The results provide the first insights into the successive operations in the olfactory bulb, and demonstrate the significance of the modular organization around glomeruli. This layered organization is especially important for natural odor inputs, because they activate many overlapping glomeruli.

  19. Chronic Spinal Injury Repair by Olfactory Bulb Ensheathing Glia and Feasibility for Autologous Therapy

    Science.gov (United States)

    Muñoz-Quiles, Cintia; Santos-Benito, Fernando F.; Llamusí, M. Beatriz; Ramón-Cueto, Almudena

    2009-01-01

    Olfactory bulb ensheathing glia (OB-OEG) promote repair of spinal cord injury (SCI) in rats after transplantation at acute or subacute (up to 45 days) stages. The most relevant clinical scenario in humans, however, is chronic SCI, in which no more major cellular or molecular changes occur at the injury site; this occurs after the third month in rodents. Whether adult OB-OEG grafts promote repair of severe chronic SCI has not been previously addressed. Rats with complete SCI that were transplanted with OB-OEG 4 months after injury exhibited progressive improvement in motor function and axonal regeneration from different brainstem nuclei across and beyond the SCI site. A positive correlation between motor outcome and axonal regeneration suggested a role for brainstem neurons in the recovery. Functional and histological outcomes did not differ at subacute or chronic stages. Thus, autologous transplantation is a feasible approach as there is time for patient stabilization and OEG preparation in human chronic SCI; the healing effects of OB-OEG on established injuries may offer new therapeutic opportunities for chronic SCI patients. PMID:19915486

  20. Kinase activity in the olfactory bulb is required for odor memory consolidation.

    Science.gov (United States)

    Tong, Michelle T; Kim, Tae-Young P; Cleland, Thomas A

    2018-05-01

    Long-term fear memory formation in the hippocampus and neocortex depends upon brain-derived neurotrophic factor (BDNF) signaling after acquisition. Incremental, appetitive odor discrimination learning is thought to depend substantially on the differentiation of adult-born neurons within the olfactory bulb (OB)-a process that is closely associated with BDNF signaling. We sought to elucidate the role of neurotrophin signaling within the OB on odor memory consolidation. Male mice were trained on odor-reward associative discriminations after bilateral infusion of the kinase inhibitor K252a, or vehicle control, into the OB. K252a is a partially selective inhibitor of tyrosine kinase (Trk) receptors, including the TrkB receptor for BDNF, though it also inhibits other plasticity-related kinases such as PKC and CaMKII/IV. K252a infusion into the OB did not impair odor acquisition or short-term (2 h) memory for the learned discriminations, but significantly impaired long-term (48 h) odor memory (LTM). This LTM deficit also was associated with reduced selectivity for the conditioned odorant in a reward-seeking digging task. Infusions of K252a immediately prior to testing did not impair LTM recall. These results indicate that kinase activation in the OB is required for the consolidation of odor memory of incrementally acquired information. © 2018 Tong et al.; Published by Cold Spring Harbor Laboratory Press.

  1. Sequential generation of olfactory bulb glutamatergic neurons by Neurog2-expressing precursor cells

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    Brill Monika S

    2011-04-01

    Full Text Available Abstract Background While the diversity and spatio-temporal origin of olfactory bulb (OB GABAergic interneurons has been studied in detail, much less is known about the subtypes of glutamatergic OB interneurons. Results We studied the temporal generation and diversity of Neurog2-positive precursor progeny using an inducible genetic fate mapping approach. We show that all subtypes of glutamatergic neurons derive from Neurog2 positive progenitors during development of the OB. Projection neurons, that is, mitral and tufted cells, are produced at early embryonic stages, while a heterogeneous population of glutamatergic juxtaglomerular neurons are generated at later embryonic as well as at perinatal stages. While most juxtaglomerular neurons express the T-Box protein Tbr2, those generated later also express Tbr1. Based on morphological features, these juxtaglomerular cells can be identified as tufted interneurons and short axon cells, respectively. Finally, targeted electroporation experiments provide evidence that while the majority of OB glutamatergic neurons are generated from intrabulbar progenitors, a small portion of them originate from extrabulbar regions at perinatal ages. Conclusions We provide the first comprehensive analysis of the temporal and spatial generation of OB glutamatergic neurons and identify distinct populations of juxtaglomerular interneurons that differ in their antigenic properties and time of origin.

  2. The Role of Adult-Born Neurons in the Constantly Changing Olfactory Bulb Network

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    Sarah Malvaut

    2016-01-01

    Full Text Available The adult mammalian brain is remarkably plastic and constantly undergoes structurofunctional modifications in response to environmental stimuli. In many regions plasticity is manifested by modifications in the efficacy of existing synaptic connections or synapse formation and elimination. In a few regions, however, plasticity is brought by the addition of new neurons that integrate into established neuronal networks. This type of neuronal plasticity is particularly prominent in the olfactory bulb (OB where thousands of neuronal progenitors are produced on a daily basis in the subventricular zone (SVZ and migrate along the rostral migratory stream (RMS towards the OB. In the OB, these neuronal precursors differentiate into local interneurons, mature, and functionally integrate into the bulbar network by establishing output synapses with principal neurons. Despite continuous progress, it is still not well understood how normal functioning of the OB is preserved in the constantly remodelling bulbar network and what role adult-born neurons play in odor behaviour. In this review we will discuss different levels of morphofunctional plasticity effected by adult-born neurons and their functional role in the adult OB and also highlight the possibility that different subpopulations of adult-born cells may fulfill distinct functions in the OB neuronal network and odor behaviour.

  3. The Role of Adult-Born Neurons in the Constantly Changing Olfactory Bulb Network

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    Malvaut, Sarah; Saghatelyan, Armen

    2016-01-01

    The adult mammalian brain is remarkably plastic and constantly undergoes structurofunctional modifications in response to environmental stimuli. In many regions plasticity is manifested by modifications in the efficacy of existing synaptic connections or synapse formation and elimination. In a few regions, however, plasticity is brought by the addition of new neurons that integrate into established neuronal networks. This type of neuronal plasticity is particularly prominent in the olfactory bulb (OB) where thousands of neuronal progenitors are produced on a daily basis in the subventricular zone (SVZ) and migrate along the rostral migratory stream (RMS) towards the OB. In the OB, these neuronal precursors differentiate into local interneurons, mature, and functionally integrate into the bulbar network by establishing output synapses with principal neurons. Despite continuous progress, it is still not well understood how normal functioning of the OB is preserved in the constantly remodelling bulbar network and what role adult-born neurons play in odor behaviour. In this review we will discuss different levels of morphofunctional plasticity effected by adult-born neurons and their functional role in the adult OB and also highlight the possibility that different subpopulations of adult-born cells may fulfill distinct functions in the OB neuronal network and odor behaviour. PMID:26839709

  4. Adult neurogenesis and specific replacement of interneuron subtypes in the mouse main olfactory bulb

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    LaRocca Greg

    2007-11-01

    Full Text Available Abstract Background New neurons are generated in the adult brain from stem cells found in the subventricular zone (SVZ. These cells proliferate in the SVZ, generating neuroblasts which then migrate to the main olfactory bulb (MOB, ending their migration in the glomerular layer (GLL and the granule cell layer (GCL of the MOB. Neuronal populations in these layers undergo turnover throughout life, but whether all neuronal subtypes found in these areas are replaced and when neurons begin to express subtype-specific markers is not known. Results Here we use BrdU injections and immunohistochemistry against (calretinin, calbindin, N-copein, tyrosine hydroxylase and GABA and show that adult-generated neurons express markers of all major subtypes of neurons in the GLL and GCL. Moreover, the fractions of new neurons that express subtype-specific markers at 40 and 75 days post BrdU injection are very similar to the fractions of all neurons expressing these markers. We also show that many neurons in the glomerular layer do not express NeuN, but are readily and specifically labeled by the fluorescent nissl stain Neurotrace. Conclusion The expression of neuronal subtype-specific markers by new neurons in the GLL and GCL changes rapidly during the period from 14–40 days after BrdU injection before reaching adult levels. This period may represent a critical window for cell fate specification similar to that observed for neuronal survival.

  5. Morphological analysis of activity-reduced adult-born neurons in the mouse olfactory bulb

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    Jeffrey E Dahlen

    2011-05-01

    Full Text Available Adult born neurons are added to the olfactory bulb (OB throughout life in rodents. While many factors have been identified as regulating the survival and integration of adult-born neurons (ABNs into existing circuitry, the understanding of how these factors affect ABN morphology and connectivity is limited. Here we compare how cell intrinsic (siRNA knock down of voltage gated sodium channels NaV1.1-1.3 and circuit level (naris occlusion reductions in activity affect ABN morphology during integration into the OB. We found that both manipulations reduce the number of dendritic spines (and thus likely the number of reciprocal synaptic connections formed with the surrounding circuitry and inhibited dendritic ramification of ABNs. Further, we identified regions of ABN apical dendrites where the largest and most significant decreases occur following siRNA knock down or naris occlusion. In siRNA knock down cells, reduction of spines is observed in proximal regions of the apical dendrite. This suggests that distal regions of the dendrite may remain active independent of NaV1.1-1.3 channel expression, perhaps facilitated by activation of T-type calcium channels and NMDA receptors. By contrast, circuit level reduction of activity by naris occlusion resulted in a global depression of spine number. Together, these results indicate that ABNs retain the ability to develop their typical overall morphological features regardless of experienced activity, and activity modulates the number and location of formed connections.

  6. Lgl1 Is Required for Olfaction and Development of Olfactory Bulb in Mice

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    Li, Zhenzu; Zhang, Tingting; Lin, Zhuchun; Hou, Congzhe; Zhang, Jian; Men, Yuqin; Li, Huashun

    2016-01-01

    Lethal giant larvae 1 (Lgl1) was initially identified as a tumor suppressor in Drosophila and functioned as a key regulator of epithelial polarity and asymmetric cell division. In this study, we generated Lgl1 conditional knockout mice mediated by Pax2-Cre, which is expressed in olfactory bulb (OB). Next, we examined the effects of Lgl1 loss in the OB. First, we determined the expression patterns of Lgl1 in the neurogenic regions of the embryonic dorsal region of the LGE (dLGE) and postnatal OB. Furthermore, the Lgl1 conditional mutants exhibited abnormal morphological characteristics of the OB. Our behavioral analysis exhibited greatly impaired olfaction in Lgl1 mutant mice. To elucidate the possible mechanisms of impaired olfaction in Lgl1 mutant mice, we investigated the development of the OB. Interestingly, reduced thickness of the MCL and decreased density of mitral cells (MCs) were observed in Lgl1 mutant mice. Additionally, we observed a dramatic loss in SP8+ interneurons (e.g. calretinin and GABAergic/non-dopaminergic interneurons) in the GL of the OB. Our results demonstrate that Lgl1 is required for the development of the OB and the deletion of Lgl1 results in impaired olfaction in mice. PMID:27603780

  7. Structure and chemical organization of the accessory olfactory bulb in the goat.

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    Mogi, Kazutaka; Sakurai, Katsuyasu; Ichimaru, Toru; Ohkura, Satoshi; Mori, Yuji; Okamura, Hiroaki

    2007-03-01

    The structure and chemical composition of the accessory olfactory bulb (AOB) were examined in male and female goats. Sections were subjected to either Nissl staining, Klüver-Barrera staining, lectin histochemistry, or immunohistochemistry for nitric oxide synthase (NOS), neuropeptide Y (NPY), tyrosine hydroxylase (TH), dopamine beta-hydroxylase (DBH), and glutamic acid decarboxylase (GAD). The goat AOB was divided into four layers: the vomeronasal nerve layer (VNL), glomerular layer (GL), mitral/tufted (M/T) cell layer (MTL), and granule cell layer (GRL). Quantitative and morphometric analyses indicated that a single AOB contained 5,000-8,000 putative M/T cells with no sex differences, whereas the AOB was slightly larger in males. Of the 21 lectins examined, 7 specifically bound to the VNL and GL, and 1 bound not only to the VNL, but also to the MTL and GRL. In either of these cases, no heterogeneity of lectin staining was observed in the rostrocaudal direction. NOS-, TH-, DBH-, and GAD-immunoreactivity (ir) were observed in the MTL and GRL, whereas NPY-ir was present only in the GRL. In the GL, periglomerular cells with GAD-ir were found in abundance, and a subset of periglomerular cells containing TH-ir was also found. Double-labeling immunohistochemistry revealed that virtually all periglomerular cells containing TH-ir were colocalized with GAD-ir.

  8. The influence of early life interventions on olfactory memory related to palatable food, and on oxidative stress parameters and Na+/K+-ATPase activity in the hippocampus and olfactory bulb of female adult rats.

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    Noschang, Cristie; Krolow, Rachel; Arcego, Danusa M; Laureano, Daniela; Fitarelli, Luiza D; Huffell, Ana Paula; Ferreira, Andréa G K; da Cunha, Aline A; Machado, Fernanda Rossato; Wyse, Angela T S; Dalmaz, Carla

    2012-08-01

    The effects of neonatal handling and the absence of ovarian hormones on the olfactory memory related to a palatable food in adulthood were investigated. Oxidative stress parameters and Na+/K+-ATPase activity in the hippocampus and olfactory bulb of adult pre-puberty ovariectomized female rats handled or not in the neonatal period were also evaluated. Litters were non-handled or handled (10 min/day, days 1-10 after birth). Females from each litter were divided into: OVX (subjected to ovariectomy), sham, and intact. When adults, olfactory memory related to a palatable food (chocolate) was evaluate using the hole-board olfactory task. Additionally, oxidative stress parameters and Na+/K+-ATPase activity were measured in the hippocampus and olfactory bulb. No difference between groups was observed considering olfactory memory evaluation. Neonatal handled rats presented an increase in Na+/K+-ATPase activity in the hippocampus and in the olfactory bulb, compared to non-handled ones. Considering the surgical procedure, there was a decrease in Na+/K+-ATPase and catalase activities in sham and OVX groups, compared to intact animals in the olfactory bulb. We concluded that olfactory memory related to a palatable food in adulthood was not affected by neonatal handling or by pre-puberty surgery, with or without removal of ovaries. The difference observed between groups in catalase and Na+/K+-ATPase activity does not seem to be related to the olfactory memory. Additionally, the increase in Na+/K+-ATPase activity (an enzyme that maintains the neurochemical gradient necessary for neuronal excitability) induced by neonatal handling may be related to neuroplastic changes in the hippocampus and olfactory bulb.

  9. The Alzheimer's β-secretase enzyme BACE1 is required for accurate axon guidance of olfactory sensory neurons and normal glomerulus formation in the olfactory bulb

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    Rajapaksha Tharinda W

    2011-12-01

    Full Text Available Abstract Background The β-secretase, β-site amyloid precursor protein cleaving enzyme 1 (BACE1, is a prime therapeutic target for lowering cerebral β-amyloid (Aβ levels in Alzheimer's disease (AD. Clinical development of BACE1 inhibitors is being intensely pursued. However, little is known about the physiological functions of BACE1, and the possibility exists that BACE1 inhibition may cause mechanism-based side effects. Indeed, BACE1-/- mice exhibit a complex neurological phenotype. Interestingly, BACE1 co-localizes with presynaptic neuronal markers, indicating a role in axons and/or terminals. Moreover, recent studies suggest axon guidance molecules are potential BACE1 substrates. Here, we used a genetic approach to investigate the function of BACE1 in axon guidance of olfactory sensory neurons (OSNs, a well-studied model of axon targeting in vivo. Results We bred BACE1-/- mice with gene-targeted mice in which GFP is expressed from the loci of two odorant-receptors (ORs, MOR23 and M72, and olfactory marker protein (OMP to produce offspring that were heterozygous for MOR23-GFP, M72-GFP, or OMP-GFP and were either BACE1+/+ or BACE1-/-. BACE1-/- mice had olfactory bulbs (OBs that were smaller and weighed less than OBs of BACE1+/+ mice. In wild-type mice, BACE1 was present in OSN axon terminals in OB glomeruli. In whole-mount preparations and tissue sections, many OB glomeruli from OMP-GFP; BACE1-/- mice were malformed compared to wild-type glomeruli. MOR23-GFP; BACE1-/- mice had an irregular MOR23 glomerulus that was innervated by randomly oriented, poorly fasciculated OSN axons compared to BACE1+/+ mice. Most importantly, M72-GFP; BACE1-/- mice exhibited M72 OSN axons that were mis-targeted to ectopic glomeruli, indicating impaired axon guidance in BACE1-/- mice. Conclusions Our results demonstrate that BACE1 is required for the accurate targeting of OSN axons and the proper formation of glomeruli in the OB, suggesting a role for BACE1 in

  10. A model of olfactory associative learning

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    Tavoni, Gaia; Balasubramanian, Vijay

    We propose a mechanism, rooted in the known anatomy and physiology of the vertebrate olfactory system, by which presentations of rewarded and unrewarded odors lead to formation of odor-valence associations between piriform cortex (PC) and anterior olfactory nucleus (AON) which, in concert with neuromodulators release in the bulb, entrains a direct feedback from the AON representation of valence to a group of mitral cells (MCs). The model makes several predictions concerning MC activity during and after associative learning: (a) AON feedback produces synchronous divergent responses in a localized subset of MCs; (b) such divergence propagates to other MCs by lateral inhibition; (c) after learning, MC responses reconverge; (d) recall of the newly formed associations in the PC increases feedback inhibition in the MCs. These predictions have been confirmed in disparate experiments which we now explain in a unified framework. For cortex, our model further predicts that the response divergence developed during learning reshapes odor representations in the PC, with the effects of (a) decorrelating PC representations of odors with different valences, (b) increasing the size and reliability of those representations, and enabling recall correction and redundancy reduction after learning. Simons Foundation for Mathematical Modeling of Living Systems.

  11. Egr-1 antisense oligodeoxynucleotide administration into the olfactory bulb impairs olfactory learning in the greater short-nosed fruit bat Cynopterus sphinx.

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    Ganesh, Ambigapathy; Bogdanowicz, Wieslaw; Balamurugan, Krishnaswamy; Ragu Varman, Durairaj; Rajan, Koilmani Emmanuvel

    2012-08-30

    Postsynaptic densities (PSDs) contain proteins that regulate synaptic transmission. We examined two important examples of these, calcium/calmodulin-dependent protein kinase II (CaMKII) and PSD-95, in regard to the functional role of early growth response gene-1 (egr-1) in regulation of olfactory learning in the greater short-nosed fruit bat Cynopterus sphinx (family Pteropodidae). To test whether activation of egr-1 in the olfactory bulb (OB) is required for olfactory memory of these bats, bilaterally canulated individuals were infused with antisense (AS) or non-sense (NS)-oligodeoxynucleotides (ODN) of egr-1, or with phosphate buffer saline (PBS), 2h before the olfactory training. Our results showed that behavioral training significantly up-regulates immediate early gene (IEG) EGR-1 and key synaptic proteins Synaptotagmin-1(SYT-1), CaMKII and PSD-95, and phosphorylation of CaMKII in the OB at the protein level per se. Subsequently, we observed that egr-1 antisense-ODN infusion in the OB impaired olfactory memory and down regulates the expression of CaMKII and PSD-95, and the phosphorylation of CaMKII but not SYT-1. In contrast, NS-ODN or PBS had no effect on the expression of the PSDs CaMKII or PSD-95, or on the phosphorylation of CaMKII. When the egr-1 NS-ODN was infused in the OB after training for the novel odor there was no effect on olfactory memory. These findings suggest that egr-1 control the activation of CaMKII and PSD-95 during the process of olfactory memory formation. Copyright © 2012 Elsevier B.V. All rights reserved.

  12. Organisation and tyrosine hydroxylase and calretinin immunoreactivity in the main olfactory bulb of paca (Cuniculus paca): a large caviomorph rodent.

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    Sasahara, Tais Harumi de Castro; Leal, Leonardo Martins; Spillantini, Maria Grazia; Machado, Márcia Rita Fernandes

    2015-04-01

    The majority of neuroanatomical and chemical studies of the olfactory bulb have been performed in small rodents, such as rats and mice. Thus, this study aimed to describe the organisation and the chemical neuroanatomy of the main olfactory bulb (MOB) in paca, a large rodent belonging to the Hystricomorpha suborder and Caviomorpha infraorder. For this purpose, histological and immunohistochemical procedures were used to characterise the tyrosine hydroxylase (TH) and calretinin (CR) neuronal populations and their distribution. The paca MOB has eight layers: the olfactory nerve layer (ONL), the glomerular layer (GL), the external plexiform layer (EPL; subdivided into the inner and outer sublayers), the mitral cell layer (MCL), the internal plexiform layer (IPL), the granule cell layer (GCL), the periventricular layer and the ependymal layer. TH-ir neurons were found mostly in the GL, and moderate numbers of TH-ir neurons were scattered in the EPL. Numerous varicose fibres were distributed in the IPL and in the GCL. CR-ir neurons concentrated in the GL, around the base of the olfactory glomeruli. Most of the CR-ir neurons were located in the MCL, IPL and GCL. Some of the granule cells had an apical dendrite with a growth cone. The CR immunoreactivity was also observed in the ONL with olfactory nerves strongly immunostained. This study has shown that the MOB organisation in paca is consistent with the description in other mammals. The characterisation and distribution of the population of TH and CR in the MOB is not exclusively to this species. This large rodent shares common patterns to other caviomorph rodent, as guinea pig, and to the myomorph rodents, as mice, rats and hamsters.

  13. Activation of GABA(A) receptors in the accessory olfactory bulb does not prevent the formation of an olfactory memory in mice.

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    Otsuka, T; Hashida, M; Oka, T; Kaba, H

    2001-07-01

    When female mice are mated, they form a memory to the pheromonal signal of their male partner. The neural mechanisms underlying this memory involve changes at the reciprocal dendrodendritic synapses between glutamatergic mitral cells and gamma-aminobutyric acid (GABA)-ergic granule cells in the accessory olfactory bulb (AOB). Blockade of GABA(A) receptors in the AOB leads to the formation of an olfactory memory. In an attempt to disrupt memory formation at mating, we used local infusions of the GABA(A) receptor agonist muscimol into the AOB during the critical period for memory formation. Muscimol across a wide range of doses (1-1000 pmol) did not prevent memory formation. The resistance of this memory to GABA(A) receptor activation may reflect the complexity of synaptic microcircuits in the AOB.

  14. Extracting Behaviorally Relevant Traits from Natural Stimuli: Benefits of Combinatorial Representations at the Accessory Olfactory Bulb.

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    Anat Kahan

    2016-03-01

    Full Text Available For many animals, chemosensation is essential for guiding social behavior. However, because multiple factors can modulate levels of individual chemical cues, deriving information about other individuals via natural chemical stimuli involves considerable challenges. How social information is extracted despite these sources of variability is poorly understood. The vomeronasal system provides an excellent opportunity to study this topic due to its role in detecting socially relevant traits. Here, we focus on two such traits: a female mouse's strain and reproductive state. In particular, we measure stimulus-induced neuronal activity in the accessory olfactory bulb (AOB in response to various dilutions of urine, vaginal secretions, and saliva, from estrus and non-estrus female mice from two different strains. We first show that all tested secretions provide information about a female's receptivity and genotype. Next, we investigate how these traits can be decoded from neuronal activity despite multiple sources of variability. We show that individual neurons are limited in their capacity to allow trait classification across multiple sources of variability. However, simple linear classifiers sampling neuronal activity from small neuronal ensembles can provide a substantial improvement over that attained with individual units. Furthermore, we show that some traits are more efficiently detected than others, and that particular secretions may be optimized for conveying information about specific traits. Across all tested stimulus sources, discrimination between strains is more accurate than discrimination of receptivity, and detection of receptivity is more accurate with vaginal secretions than with urine. Our findings highlight the challenges of chemosensory processing of natural stimuli, and suggest that downstream readout stages decode multiple behaviorally relevant traits by sampling information from distinct but overlapping populations of AOB neurons.

  15. Estradiol-induced neurogenesis in the female accessory olfactory bulb is required for the learning of the male odor.

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    Brus, Maïna; Trouillet, Anne-Charlotte; Hellier, Vincent; Bakker, Julie

    2016-08-01

    Odors processed by the main and accessory olfactory bulbs (MOB, AOB) are important for sexual behavior. Interestingly, both structures continue to receive new neurons during adulthood. A role for olfactory neurogenesis in sexual behavior in female mice has recently been shown and gonadal hormones such as estradiol can modulate adult neurogenesis. Therefore, we wanted to determine the role of estradiol in learning the odors of sexual partners and in the adult neurogenesis of female aromatase knockout mice (ArKO), unable to produce estradiol. Female wild-type (WT) and ArKO mice were exposed to male odors during 7 days, and olfactory preferences, cell proliferation, cell survival and functional involvement of newborn neurons were analyzed, using BrdU injections, in combination with a marker of cell activation (Zif268) and neuronal fate (doublecortin, NeuN). Behavioral tasks indicated that both WT and ArKO females were able to discriminate between the odors of two different males, but ArKO mice failed to learn the familiar male odor. Proliferation of newborn cells was reduced in ArKO mice only in the dentate gyrus of the hippocampus. Olfactory exposure decreased cell survival in the AOB in WT females, suggesting a role for estradiol in a structure involved in sexual behavior. Finally, newborn neurons do not seem to be functionally involved in the AOB of ArKO mice compared with WT, when females were exposed to the odor of a familiar male, suggesting that estradiol-induced neurogenesis in the AOB is required for the learning of the male odor in female mice. Aromatase knockout mice (ArKO) presented deficits in olfactory preferences without affecting their olfactory discrimination abilities, and showed no functional involvement of newborn neurons in the accessory olfactory bulb (AOB) in response to the odor of a familiar male. These results suggest that estradiol-induced neurogenesis in the female AOB is required for the learning of the male odor. © 2016 International

  16. Precision of Classification of Odorant Value by the Power of Olfactory Bulb Oscillations Is Altered by Optogenetic Silencing of Local Adrenergic Innervation

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    Daniel Ramirez-Gordillo

    2018-03-01

    Full Text Available Neuromodulators such as noradrenaline appear to play a crucial role in learning and memory. The goal of this study was to determine the role of norepinephrine in representation of odorant identity and value by olfactory bulb oscillations in an olfactory learning task. We wanted to determine whether the different bandwidths of olfactory bulb oscillations encode information involved in associating the odor with the value, and whether norepinephrine is involved in modulating this association. To this end mice expressing halorhodopsin under the dopamine-beta-hydrolase (DBH promoter received an optetrode implant targeted to the olfactory bulb. Mice learned to differentiate odorants in a go-no-go task. A receiver operating characteristic (ROC analysis showed that there was development of a broadband differential rewarded vs. unrewarded odorant-induced change in the power of local field potential oscillations as the mice became proficient in discriminating between two odorants. In addition, the change in power reflected the value of the odorant rather than the identity. Furthermore, optogenetic silencing of local noradrenergic axons in the olfactory bulb altered the differential oscillatory power response to the odorants for the theta, beta, and gamma bandwidths.

  17. Precision of Classification of Odorant Value by the Power of Olfactory Bulb Oscillations Is Altered by Optogenetic Silencing of Local Adrenergic Innervation.

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    Ramirez-Gordillo, Daniel; Ma, Ming; Restrepo, Diego

    2018-01-01

    Neuromodulators such as noradrenaline appear to play a crucial role in learning and memory. The goal of this study was to determine the role of norepinephrine in representation of odorant identity and value by olfactory bulb oscillations in an olfactory learning task. We wanted to determine whether the different bandwidths of olfactory bulb oscillations encode information involved in associating the odor with the value, and whether norepinephrine is involved in modulating this association. To this end mice expressing halorhodopsin under the dopamine-beta-hydrolase (DBH) promoter received an optetrode implant targeted to the olfactory bulb. Mice learned to differentiate odorants in a go-no-go task. A receiver operating characteristic (ROC) analysis showed that there was development of a broadband differential rewarded vs. unrewarded odorant-induced change in the power of local field potential oscillations as the mice became proficient in discriminating between two odorants. In addition, the change in power reflected the value of the odorant rather than the identity. Furthermore, optogenetic silencing of local noradrenergic axons in the olfactory bulb altered the differential oscillatory power response to the odorants for the theta, beta, and gamma bandwidths.

  18. Electrophysiological evidence for a direct link between the main and accessory olfactory bulbs in the adult rat

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    Victor eVargas-Barroso

    2016-01-01

    Full Text Available It is accepted that the main- and accessory- olfactory systems exhibit overlapping responses to pheromones and odorants. We performed whole-cell patch-clamp recordings in adult rat olfactory bulb slices to define a possible interaction between the first central relay of these systems: the accessory olfactory bulb (AOB and the main olfactory bulb (MOB. This was tested by applying electrical field stimulation in the dorsal part of the MOB while recording large principal cells (LPCs of the anterior AOB (aAOB. Additional recordings of LPCs were performed at either side of the plane of intersection between the aAOB and posterior-AOB (pAOB halves, or linea alba, while applying field stimulation to the opposite half. A total of 92 recorded neurons were filled during whole-cell recordings with biocytin and studied at the light microscope. Neurons located in the aAOB (n = 6, 8% send axon collaterals to the MOB since they were antidromically activated in the presence of glutamate receptor antagonists (APV and CNQX. Recorded LPCs evoked orthodromic excitatory post-synaptic responses (n = 6, aAOB; n = 1, pAOB or antidromic action potentials (n = 8, aAOB; n = 7, pAOB when applying field stimulation to the opposite half of the recording site (e.g. recording in aAOB; stimulating in pAOB and vice-versa. Observation of the filled neurons revealed that indeed, LPCs send axon branches that cross the linea alba to resolve in the internal cellular layer. Additionally, LPCs of the aAOB send axon collaterals to dorsal-MOB territory. Notably, while performing AOB recordings we found a sub-population of neurons (24 % of the total that exhibited voltage-dependent bursts of action potentials. Our findings support the existence of: 1. a direct projection from aAOB LPCs to dorsal-MOB, 2. physiologically active synapses linking aAOB and pAOB, and 3. pacemaker-like neurons in both AOB halves. This work was presented in the form of an Abstract on SfN 2014 (719.14/EE17.

  19. Mitral and tufted cells are potential cellular targets of nitration in the olfactory bulb of aged mice.

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    Myung Jae Yang

    Full Text Available Olfactory sensory function declines with age; though, the underlying molecular changes that occur in the olfactory bulb (OB are relatively unknown. An important cellular signaling molecule involved in the processing, modulation, and formation of olfactory memories is nitric oxide (NO. However, excess NO can result in the production of peroxynitrite to cause oxidative and nitrosative stress. In this study, we assessed whether changes in the expression of 3-nitrotyrosine (3-NT, a neurochemical marker of peroxynitrite and thus oxidative damage, exists in the OB of young, adult, middle-aged, and aged mice. Our results demonstrate that OB 3-NT levels increase with age in normal C57BL/6 mice. Moreover, in aged mice, 3-NT immunoreactivity was found in some blood vessels and microglia throughout the OB. Notably, large and strongly immunoreactive puncta were found in mitral and tufted cells, and these were identified as lipofuscin granules. Additionally, we found many small-labeled puncta within the glomeruli of the glomerular layer and in the external plexiform layer, and these were localized to mitochondria and discrete segments of mitral and tufted dendritic plasma membranes. These results suggest that mitral and tufted cells are potential cellular targets of nitration, along with microglia and blood vessels, in the OB during aging.

  20. Neonatal citalopram exposure decreases serotonergic fiber density in the olfactory bulb of male but not female adult rats

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    Junlin eZhang

    2013-05-01

    Full Text Available Manipulation of serotonin (5HT during early development has been shown to induce long-lasting morphological changes within the raphe nuclear complex and serotonergic circuitry throughout the brain. Recent studies have demonstrated altered raphe-derived 5HT transporter (SERT immunoreactive axonal expression in several cortical target sites after brief perinatal exposure to selective 5HT reuptake inhibitors such as citalopram (CTM. Since the serotonergic raphe nuclear complex projects to the olfactory bulb (OB and perinatal 5HT disruption has been shown to disrupt olfactory behaviors, the goal of this study was to further investigate such developmental effects in the OB of CTM exposed animals. Male and female rat pups were exposed to CTM from postnatal day 8-21. After animals reach adulthood (>90 days, OB tissue sections were processed immunohistochemically for SERT antiserum. Our data revealed that the density of the SERT immunoreactive fibers decreased ~40% in the OB of CTM exposed male rats, but not female rats. Our findings support a broad and long-lasting change throughout most of the 5HT system, including the OB, after early manipulation of 5HT. Because dysfunction of the early 5HT system has been implicated in the etiology of neurodevelopmental disorders such as autism spectrum disorders (ASDs, these new findings may offer insight into the abnormal olfactory perception often noted in patients with ASD.

  1. Olfactory Bulb [alpha][subscript 2]-Adrenoceptor Activation Promotes Rat Pup Odor-Preference Learning via a cAMP-Independent Mechanism

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    Shakhawat, Amin MD.; Harley, Carolyn W.; Yuan, Qi

    2012-01-01

    In this study, three lines of evidence suggest a role for [alpha][subscript 2]-adrenoreceptors in rat pup odor-preference learning: olfactory bulb infusions of the [alpha][subscript 2]-antagonist, yohimbine, prevents learning; the [alpha][subscript 2]-agonist, clonidine, paired with odor, induces learning; and subthreshold clonidine paired with…

  2. Over-expression of hNGF in adult human olfactory bulb neural stem cells promotes cell growth and oligodendrocytic differentiation

    NARCIS (Netherlands)

    H.E.S. Marei (Hany); A. Althani (Asmaa); N. Afifi (Nahla); A. Abd-Elmaksoud (Ahmed); C. Bernardini (Camilla); F. Michetti (Fabrizio); M. Barba (Marta); M. Pescatori (Mario); G. Maira (Giulio); E. Paldino (Emanuela); L. Manni (Luigi); P. Casalbore (Patrizia); C. Cenciarelli (Carlo)

    2013-01-01

    textabstractThe adult human olfactory bulb neural stem/progenitor cells (OBNC/PC) are promising candidate for cell-based therapy for traumatic and neurodegenerative insults. Exogenous application of NGF was suggested as a promising therapeutic strategy for traumatic and neurodegenerative diseases,

  3. Analysis of blood flow in a third ventricular ependymoma and an olfactory bulb meningioma by usisng perfusion computed tomography

    International Nuclear Information System (INIS)

    Kishimoto, M.; Yamada, K.; Seok, J.S.; Shimizu, J.; Kobayashi, Y.; Akiba, Y.; Morishita, Y.; Iwasa, A.; Iwasaki, T.; Miyake, Y.

    2008-01-01

    Brain perfusion computed tomography (CT) scanning was performed in a mongrel dog and a golden retriever that were diagnosed with third ventricular tumor and olfactory bulb tumor, respectively, by contrast-enhanced CT. The tumors were pathologically diagnosed as ependymoma and meningioma, respectively. Perfusion CT results revealed that the ependymoma in this study had a lower blood flow, higher blood volume, and greater transit time of blood than the adjacent brain tissue. Further, the meningioma in this study had a higher blood flow, higher blood volume, and greater transit time of blood than the adjacent brain tissue. Perfusion CT can potentially be used for the grading of brain tumors and narrowing differential diagnosis, provided the perfusion CT data of animals are accumulated

  4. Altered morphologies and functions of the olfactory bulb and hippocampus induced by miR-30c

    Directory of Open Access Journals (Sweden)

    Tingting eSun

    2016-05-01

    Full Text Available Adult neurogenesis is considered to contribute to a certain degree of plasticity for the brain. However, the effects of adult-born neurons on the brain are still largely unknown. Here, we specifically altered the expression of miR-30c in the subventricular zone (SVZ and dentate gyrus (DG by stereotaxic injection with their respective up-and down-regulated lentiviruses. Results showed an increased level of miR-30c enhanced adult neurogenesis by prompting cell-cycles of stem cells, whereas down-regulated miR-30c led to the opposite results. When these effects of miR-30c lasted for three months, we detected significant morphological changes in the olfactory bulb (OB and lineage alteration in the hippocampus. Tests of olfactory sensitivity and associative and spatial memory showed that a certain amount of adult-born neurons are essential for the normal functions of the OB and hippocampus, but there also exist redundant newborn neurons that do not further improve the functioning of these areas. Our study revealed the interactions between miRNA, adult neurogenesis, brain morphology and function, and this provides a novel insight into understanding the role of newborn neurons in the adult brain.

  5. Retrograde monosynaptic tracing reveals the temporal evolution of inputs onto new neurons in the adult dentate gyrus and olfactory bulb

    Science.gov (United States)

    Deshpande, Aditi; Bergami, Matteo; Ghanem, Alexander; Conzelmann, Karl-Klaus; Lepier, Alexandra; Götz, Magdalena; Berninger, Benedikt

    2013-01-01

    Identifying the connectome of adult-generated neurons is essential for understanding how the preexisting circuitry is refined by neurogenesis. Changes in the pattern of connectivity are likely to control the differentiation process of newly generated neurons and exert an important influence on their unique capacity to contribute to information processing. Using a monosynaptic rabies virus-based tracing technique, we studied the evolving presynaptic connectivity of adult-generated neurons in the dentate gyrus (DG) of the hippocampus and olfactory bulb (OB) during the first weeks of their life. In both neurogenic zones, adult-generated neurons first receive local connections from multiple types of GABAergic interneurons before long-range projections become established, such as those originating from cortical areas. Interestingly, despite fundamental similarities in the overall pattern of evolution of presynaptic connectivity, there were notable differences with regard to the development of cortical projections: although DG granule neuron input originating from the entorhinal cortex could be traced starting only from 3 to 5 wk on, newly generated neurons in the OB received input from the anterior olfactory nucleus and piriform cortex already by the second week. This early glutamatergic input onto newly generated interneurons in the OB was matched in time by the equally early innervations of DG granule neurons by glutamatergic mossy cells. The development of connectivity revealed by our study may suggest common principles for incorporating newly generated neurons into a preexisting circuit. PMID:23487772

  6. Plasticity in the olfactory bulb of the maternal mouse is prevented by gestational stress

    Science.gov (United States)

    Belnoue, Laure; Malvaut, Sarah; Ladevèze, Elodie; Abrous, Djoher Nora; Koehl, Muriel

    2016-01-01

    Maternal stress is associated with an altered mother-infant relationship that endangers offspring development, leading to emotional/behavioral problems. However, little research has investigated the stress-induced alterations of the maternal brain that could underlie such a disruption of mother-infant bonding. Olfactory cues play an extensive role in the coordination of mother-infant interactions, suggesting that motherhood may be associated to enhanced olfactory performances, and that this effect may be abolished by maternal stress. To test this hypothesis, we analyzed the impact of motherhood under normal conditions or after gestational stress on olfactory functions in C57BL/6 J mice. We report that gestational stress alters maternal behavior and prevents both mothers’ ability to discriminate pup odors and motherhood-induced enhancement in odor memory. We investigated adult bulbar neurogenesis as a potential mechanism of the enhanced olfactory function in mothers and found that motherhood was associated with an increased complexity of the dendritic tree of newborn neurons. This motherhood-evoked remodeling was totally prevented by gestational stress. Altogether, our results may thus provide insight into the neural changes that could contribute to altered maternal behavior in stressed mothers. PMID:27886228

  7. Internal cholinergic regulation of learning and recall in a model of olfactory processing

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    Licurgo Benemann Almeida

    2016-11-01

    Full Text Available In the olfactory system, cholinergic modulation has been associated with contrast modulation and changes in receptive fields in the olfactory bulb, as well the learning of odor associations in olfactory cortex. Computational modeling and behavioral studies suggest that cholinergic modulation could improve sensory processing and learning while preventing pro-active interference when task demands are high. However, how sensory inputs and/or learning regulate incoming modulation has not yet been elucidated. We here use a computational model of the olfactory bulb, piriform cortex (PC and horizontal limb of the diagonal band of Broca (HDB to explore how olfactory learning could regulate cholinergic inputs to the system in a closed feedback loop. In our model, the novelty of an odor is reflected in firing rates and sparseness of cortical neurons in response to that odor and these firing rates can directly regulate learning in the system by modifying cholinergic inputs to the system. In the model, cholinergic neurons reduce their firing in response to familiar odors – reducing plasticity in the PC, but increase their firing in response to novel odor – increasing PC plasticity. Recordings from HDB neurons in awake behaving rats reflect predictions from the model by showing that a subset of neurons decrease their firing as an odor becomes familiar.

  8. Reproduction phase-related expression of GnRH-like immunoreactivity in the olfactory receptor neurons, their projections to the olfactory bulb and in the nervus terminalis in the female Indian major carp Cirrhinus mrigala (Ham.).

    Science.gov (United States)

    Biju, K C; Singru, Praful S; Schreibman, Martin P; Subhedar, Nishikant

    2003-10-01

    The reproductive biology of the Indian major carp Cirrhinus mrigala is tightly synchronized with the seasonal changes in the environment. While the ovaries show growth from February through June, the fish spawn in July-August to coincide with the monsoon; thereafter the fish pass into the postspawning and resting phases. We investigated the pattern of GnRH immunoreactivity in the olfactory system at regular intervals extending over a period of 35 months. Although no signal was detected in the olfactory organ of fish collected from April through February following year, distinct GnRH-like immunoreactivity appeared in the fish collected in March. Intense immunoreactivity was noticed in several olfactory receptor neurons (ORNs) and their axonal fibers as they extend over the olfactory nerve, spread in the periphery of the olfactory bulb (OB), and terminate in the glomerular layer. Strong immunoreactivity was seen in some fascicles of the medial olfactory tracts extending from the OB to the telencephalon. Some neurons of the ganglion cells of nervus terminalis showed GnRH immunostaining during March; no immunoreactivity was detected at other times of the year. Plexus of GnRH immunoreactive fibers extending throughout the bulb represented a different component of the olfactory system; the fiber density showed a seasonal pattern that could be related to the status of gonadal maturity. While it was highest in the prespawning phase, significant reduction in the fiber density was noticed in the fish of spawning and the following regressive phases. Taken together the data suggest that the GnRH in the olfactory system of C. mrigala may play a major role in translation of the environmental cues and influence the downstream signals leading to the stimulation of the brain-pituitary-ovary axis.

  9. MODELS OF HOURLY DRY BULB TEMPERATURE AND ...

    African Journals Online (AJOL)

    Hourly meteorological data of both dry bulb temperature and relative humidity for 18 locations in Nigeria for the period 1995 to 2009 were analysed to obtain the mean monthly average and monthly hourly average of each of the two meteorological variables for each month for each location. The difference between the ...

  10. Early Paradoxical Increase of Dopamine: A Neurochemical Study of Olfactory Bulb in Asymptomatic and Symptomatic MPTP Treated Monkeys

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    Christian Pifl

    2017-05-01

    Full Text Available Parkinson’s disease (PD is a neurodegenerative disease with both motor and non-motor manifestations. Hyposmia is one of the early non-motor symptoms, which can precede motor symptoms by several years. The relationship between hyposmia and PD remains elusive. Olfactory bulb (OB pathology shows an increased number of olfactory dopaminergic cells, protein aggregates and dysfunction of neurotransmitter systems. In this study we examined tissue levels of dopamine (DA and serotonin (5-hydroxytryptamine, 5-HT and their metabolites, of noradrenaline (NA and of the amino acid neurotransmitters aspartate, glutamate, taurine and γ-aminobutyric acid in OBs of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP treated Macaca fascicularis in different stages, including monkeys who were always asymptomatic, monkeys who recovered from mild parkinsonian signs, and monkeys with stable moderate or severe parkinsonism. DA was increased compared to controls, while neither NA and 5-HT nor the amino acid neurotransmitters were significantly changed. Furthermore, DA increased before stable motor deficits appear with +51% in asymptomatic and +96% in recovered monkeys. Unchanged DA metabolites suggest a special metabolic profile of the newly formed DA neurons. Significant correlation of homovanillic acid (HVA with taurine single values within the four MPTP groups and of aspartate with taurine within the asymptomatic and recovered MPTP groups, but not within the controls suggest interactions in the OB between taurine and the DA system and taurine and the excitatory neurotransmitter triggered by MPTP. This first investigation of OB in various stages after MPTP administration suggests that the DA increase seems to be an early phenomenon, not requiring profound nigrostriatal neurodegeneration or PD symptoms.

  11. SRXRF analysis of elemental distribution in the olfactory bulbs of rat after intranaris application of manganese chloride

    International Nuclear Information System (INIS)

    He Rui; Wang Xuxia; Lei Hao; Liu Nianqing; Huang Yuying; He Wei

    2005-01-01

    Manganese is a calcium analog, and it can enter activated neurons through voltage-gated calcium channel. Overexposure to manganese often result in its accumulation in the brain, causing symptoms similar to Parkinson's disease One of the routes by which manganese enters brain is the olfactory pathway. In this work, elementary distribution in the olfactory bulbs (OB) of rats after intranaris application of MnCl 2 solution was measured by SRXRF, and the effect of exogenous Mn on the distribution of other elements, particularly calcium, in the OB was also investigated. Four SD male rats were decapitated 9 hrs after intranaris application of MnCl 2 solution (5 μl, 400 mmol/L) in the right nasal cavity. The OB were removed, frozen by liquid nitrogen, cut into 100 m-thick sections with a microtome, and put onto polycarbonate films specially designed for SRXRF examination. It has been shown that unilateral intranaris application of MnCl 2 only results in manganese deposition in the ipsilateral hemisphere of the OB. The left hemisphere of the OB was therefore used as the control. All SRXRF spectra collected with a beam spot size of 60 m x 80 m were normalized to the acquisition time and the counting of the ion chambers, and the contribution from the supporting polycarbonate film was subtracted. The X-ray peak area for each element (A) and the Compton scattering intensity (B) for the whole OB section were obtained. The relative content for each element was taken as the ratio of A to B and analyzed by the SPSS software. The average Mn and Ca contents were found significantly higher in the ipsilateral hemisphere than in the contralateral hemisphere. The Mn content was found to be the highest in the glomerular layer (GL) of the ipsilateral OB hemisphere, consistent with previous findings obtained by magnetic resonance imaging detection. Bivariate correlation analysis showed that the distribution of Mn and Ca in the ipsilateral hemisphere had higher degree of correlation

  12. Npas4 Regulates Mdm2 and thus Dcx in Experience-Dependent Dendritic Spine Development of Newborn Olfactory Bulb Interneurons

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    Sei-ichi Yoshihara

    2014-08-01

    Full Text Available Sensory experience regulates the development of various brain structures, including the cortex, hippocampus, and olfactory bulb (OB. Little is known about how sensory experience regulates the dendritic spine development of OB interneurons, such as granule cells (GCs, although it is well studied in mitral/tufted cells. Here, we identify a transcription factor, Npas4, which is expressed in OB GCs immediately after sensory input and is required for dendritic spine formation. Npas4 overexpression in OB GCs increases dendritic spine density, even under sensory deprivation, and rescues reduction of dendrite spine density in the Npas4 knockout OB. Furthermore, loss of Npas4 upregulates expression of the E3-ubiquitin ligase Mdm2, which ubiquitinates a microtubule-associated protein Dcx. This leads to reduction in the dendritic spine density of OB GCs. Together, these findings suggest that Npas4 regulates Mdm2 expression to ubiquitinate and degrade Dcx during dendritic spine development in newborn OB GCs after sensory experience.

  13. Early x-irradiation of rats. Part 2. Effect of granule cells and their dendrodendritic synapses in the olfactory bulb

    Energy Technology Data Exchange (ETDEWEB)

    Halasz, N

    1987-01-01

    Low, repeated doses of X-rays from a Co/sup 60/ source were used to impair the development of the granule cells and their dendritic terminals in the olfactory bulb, and the resulting effect was studied under light and electron microscopes at 9 days of age. Irradiation of rats from embryonic day 18 (in utero) to postnatal day 5 resulted, among others, in maldevelopment of the (internal) granule cell and external plexiform layers. This was accompanied by a decrease in the number and the density of the granule cells, and the remaining granule cells contained less ribosomes, regardless of their position within the layer. This implies that both supposed subtypes of granule cells were effected. In the external plexiform layer, a reduced number of mature dendrodendritic synapses and signs of harmed granule gemmules were observed. The results suggest that intrauterinal plus postnatal irradiation with low, repeated doses of X-rays may be an effective tool impairing the development of prenatally forming neurons.

  14. The subrhinal paleocortex in the hedgehog tenrec: a multiarchitectonic characterization and an analysis of its connections with the olfactory bulb.

    Science.gov (United States)

    Künzle, H; Radtke-Schuller, S

    2000-12-01

    In the Madagascan hedgehog tenrec, Echinops telfairi, the entire paleocortical region (PCx) subjacent to the rhinal indentation is composed of three layers and occupies up to two thirds of the lateral hemisphere. A clear differentiation of PCx into its presumed constituents, the piriform cortex and the entorhinal cortex, as seen in other mammals, has not been obtained so far. To gain insight into location and intrinsic organization of these areas in a basal placental mammal we investigated the tenrec's PCx using cyto-, myelo- and chemoarchitectural criteria (zinc, acetylcholinesterase, NADPh-diaphorase, Wisteria floribunda agglutinin, parvalbumin, calbindin, calretinin) and analysed its connections with the olfactory bulb. The layers 2 and 3 of the tenrec's PCx differed from the corresponding layers in the rat. The layer 2 showed a complex distribution of corticobulbar cells but could not be subdivided, in contrast to layer 3. Additional cell groups in the depth of PCx were tentatively compared with subdivisions of the endopiriform region. The architectural and connectional features varied clearly along the rostrocaudal and dorso-ventral extents of PCx and gave hints for the presence of different paleocortical subdivisions. With the possible exception of an area located at the most caudal tip of the dorsomedial hemisphere, however, no conclusive evidence was obtained for the presence of a multilayered, entorhinal region. The bulbar projections to the PCx were very extensive and almost exclusively ipsilateral. The laterality of the projection is similar to that in higher mammals, but differs from that in the erinaceous hedgehog.

  15. Odor Preference Learning and Memory Modify GluA1 Phosphorylation and GluA1 Distribution in the Neonate Rat Olfactory Bulb: Testing the AMPA Receptor Hypothesis in an Appetitive Learning Model

    Science.gov (United States)

    Cui, Wen; Darby-King, Andrea; Grimes, Matthew T.; Howland, John G.; Wang, Yu Tian; McLean, John H.; Harley, Carolyn W.

    2011-01-01

    An increase in synaptic AMPA receptors is hypothesized to mediate learning and memory. AMPA receptor increases have been reported in aversive learning models, although it is not clear if they are seen with memory maintenance. Here we examine AMPA receptor changes in a cAMP/PKA/CREB-dependent appetitive learning model: odor preference learning in…

  16. Oxytocin Removes Estrous Female vs. Male Preference of Virgin Male Rats: Mediation of the Supraoptic Nucleus Via Olfactory Bulbs

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    Xiao-Yu Liu

    2017-10-01

    Full Text Available Social functions of oxytocin (OT have been explored extensively; however, relationship between the effect of intranasally applied OT (nasal OT on the social preference (SP and intracerebral actions of endogenous OT remains unclear. To resolve this question, we first observed effects of nasal OT on the SP of virgin young adult male rats toward unfamiliar virgin estrous female (EF vs. virgin male rats. The results showed that the test male rats exhibited significantly more times and longer duration accessing the female than the male, which were acutely eliminated by nasal OT. Then, we examined the approaches mediating nasal OT effects on the activity of potential brain targets in Western blots and found that nasal OT activated the olfactory bulbs (OBs and the supraoptic nucleus (SON, but not the piriform cortex, amygdala and hippocampus as shown by significant changes in the expression of c-Fos and/or phosphorylated extracellular signal-regulated protein kinase (pERK 1/2. Moreover, microinjection of TTX into the OBs blocked nasal OT-evoked increases in pERK1/2 levels as well as the molecular association between ERK1/2 and OT-neurophysin in the SON. Electrolytic lesions of the lateral olfactory tract did not significantly change the basal levels of pERK 1/2 in the SON; however, upon nasal OT, pERK 1/2 levels in the SON reduced significantly. Lastly, microinjection of L-aminoadipic acid (gliotoxin into the SON to reduce OT levels reduced the duration of the test male’s accessing the EF and blocked the nasal OT-evoked increase in the duration of test male’s accessing the male while significantly increasing pERK1/2 levels in the amygdala. These findings reveal for the first time that nasal OT acutely eliminates virgin males’ SP to EFs via the OB-SON route and that OT neurons could mediate the social effects of nasal OT by suppressing social phobia generated in the amygdala.

  17. Anisomycin administered in the olfactory bulb and dorsal hippocampus impaired social recognition memory consolidation in different time-points.

    Science.gov (United States)

    Pena, R R; Pereira-Caixeta, A R; Moraes, M F D; Pereira, G S

    2014-10-01

    To identify an individual as familiar, rodents form a specific type of memory named social recognition memory. The olfactory bulb (OB) is an important structure for social recognition memory, while the hippocampus recruitment is still controversial. The present study was designed to elucidate the OB and the dorsal hippocampus contribution to the consolidation of social memory. For that purpose, we tested the effect of anisomycin (ANI), which one of the effects is the inhibition of protein synthesis, on the consolidation of social recognition memory. Swiss adult mice with cannulae implanted into the CA1 region of the dorsal hippocampus or into the OB were exposed to a juvenile during 5 min (training session; TR), and once again 1.5 h or 24 h later to test social short-term memory (S-STM) or social long-term memory (S-LTM), respectively. To study S-LTM consolidation, mice received intra-OB or intra-CA1 infusion of saline or ANI immediately, 3, 6 or 18 h after TR. ANI impaired S-LTM consolidation in the OB, when administered immediately or 6h after TR. In the dorsal hippocampus, ANI was amnesic only if administered 3 h after TR. Furthermore, the infusion of ANI in either OB or CA1, immediately after training, did not affect S-STM. Moreover, ANI administered into the OB did not alter the animal's performance in the buried food-finding task. Altogether, our results suggest the consolidation of S-LTM requires both OB and hippocampus participation, although in different time points. This study may help shedding light on the specific roles of the OB and dorsal hippocampus in social recognition memory. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. Olfactory memory is impaired in a triple transgenic model of Alzheimer disease.

    Science.gov (United States)

    Cassano, Tommaso; Romano, Adele; Macheda, Teresa; Colangeli, Roberto; Cimmino, Concetta Stefania; Petrella, Antonio; LaFerla, Frank M; Cuomo, Vincenzo; Gaetani, Silvana

    2011-10-31

    Olfactory memory dysfunctions were investigated in the triple-transgenic murine model of Alzheimer's disease (3 × Tg-AD). In the social transmission of food preference test, 3 × Tg-AD mice presented severe deficits in odor-based memory, without gross changes in general odor-ability. Aβ and tau immunoreactivity was not observed in the primary processing regions for odor, the olfactory bulbs (OBs), whereas marked immunostaining was present in the piriform, entorhinal, and orbitofrontal cortex, as well as in the hippocampus. Our results suggest that the impairment in olfactory-based information processing might arise from degenerative mechanisms mostly affecting higher cortical regions and limbic areas, such as the hippocampus. Copyright © 2011 Elsevier B.V. All rights reserved.

  19. Effects of x irradiation on the postnatally-forming granule cell populations in the olfactory bulb, hippocampus, and cerebellum of the rat

    International Nuclear Information System (INIS)

    Bayer, S.A.; Altman, J.

    1975-01-01

    Beginning on the second postnatal day, either two (2X group), four (4X group) or six (6X group) daily or alternate daily exposures to low-level x irradiation (150 to 200 R) were used to interfere with the acquisition of granule cells in the olfactory bulb, hippocampus, and cerebellum of the rat. At 60 days of age, the relationship between post-irradiation recovery and permanent granule cell loss was assessed with two quantitative techniques. First, the total number of granule cells was determined to estimate the magnitude of permanent loss. Secondly, the number of labeled granule cells were counted on day 60 after a 3 H-thymidine injection given on either day 15 or on day 20 to estimate differential rates of cell proliferation during the recovery period. Permanent loss of granule cells was sustained in all regions by all schedules of irradiation. The time for the most effective exposures was earlier in the hippocampus and olfactory bulb than in the cerebellum. In all regions, both the irradiated groups and the controls showed a decrease in the level of cell proliferation between 15 and 20 days. The number of cells that could be labeled after either the 15 or 20 day injection was below control levels for all groups in the hippocampus, at control levels for all groups in the cerebellum, and either at (2X and 4X) or below (6X) control levels in the olfactory bulb. These results are discussed in the light of the formation time of the granule cells in each region

  20. Effects of x-irradiation on the postnatally-forming granule cell populations in the olfactory bulb, hippocampus, and cerebellum of the rat

    International Nuclear Information System (INIS)

    Bayer, S.A.; Altman, J.

    1975-01-01

    Beginning on the second postnatal day, either two (2X group), four (4X group) or six (6X group) daily or alternate daily exposures to low-level x irradiation (150-200 r) were used to interfere with the acquisition of granule cells in the olfactory bulb, hippocampus, and cerebellum of the rat. At 60 days of age, the relationship between post-irradiation recovery and permanent granule cell loss was assessed with two quantitative techniques. First, the total number of granule cells was determined to estimate the magnitude of permanent loss. Secondly, the number of labeled granule cells were counted on day 60 after a 3 H-thymidine injection given on either day 15 or on day 20 to estimate differential rates of cell proliferation during the recovery period. Permanent loss of granule cells was sustained in all regions by all schedules of irradiation. The time for the most effective exposures was earlier in the hippocampus and olfactory bulb than in the cerebellum. In all regions, both the irradiated groups and the controls showed a decrease in the level of cell proliferation between 15 and 20 days. The number of cells that could be labeled after either the 15 or 20 day injection was below control levels for all groups in the hippocampus, at control levels for all groups in the cerebellum, and either at (2X and 4X) or below (6X) control levels in the olfactory bulb. These results are discussed in the light of the formation time of the granule cells in each region

  1. A physiological increase of insulin in the olfactory bulb decreases detection of a learned aversive odor and abolishes food odor-induced sniffing behavior in rats.

    Directory of Open Access Journals (Sweden)

    Pascaline Aimé

    Full Text Available Insulin is involved in multiple regulatory mechanisms, including body weight and food intake, and plays a critical role in metabolic disorders such as obesity and diabetes. An increasing body of evidence indicates that insulin is also involved in the modulation of olfactory function. The olfactory bulb (OB contains the highest level of insulin and insulin receptors (IRs in the brain. However, a role for insulin in odor detection and sniffing behavior remains to be elucidated. Using a behavioral paradigm based on conditioned olfactory aversion (COA to isoamyl-acetate odor, we demonstrated that an intracerebroventricular (ICV injection of 14 mU insulin acutely decreased olfactory detection of fasted rats to the level observed in satiated animals. In addition, whereas fasted animals demonstrated an increase in respiratory frequency upon food odor detection, this effect was absent in fasted animals receiving a 14 mU insulin ICV injection as well as in satiated animals. In parallel, we showed that the OB and plasma insulin levels were increased in satiated rats compared to fasted rats, and that a 14 mU insulin ICV injection elevated the OB insulin level of fasted rats to that of satiated rats. We further quantified insulin receptors (IRs distribution and showed that IRs are preferentially expressed in the caudal and lateral parts of the main OB, with the highest labeling found in the mitral cells, the main OB projection neurons. Together, these data suggest that insulin acts on the OB network to modulate olfactory processing and demonstrate that olfactory function is under the control of signals involved in energy homeostasis regulation and feeding behaviors.

  2. Mitral cells of the olfactory bulb perform metabolic sensing and are disrupted by obesity at the level of the Kv1.3 ion channel.

    Directory of Open Access Journals (Sweden)

    Debra Ann Fadool

    Full Text Available Sixty-five percent of Americans are over-weight. While the neuroendocrine controls of energy homeostasis are well known, how sensory systems respond to and are impacted by obesity is scantily understood. The main accepted function of the olfactory system is to provide an internal depiction of our external chemical environment, starting from the detection of chemosensory cues. We hypothesized that the system additionally functions to encode internal chemistry via the detection of chemicals that are important indicators of metabolic state. We here uncovered that the olfactory bulb (OB subserves as an internal sensor of metabolism via insulin-induced modulation of the potassium channel Kv1.3. Using an adult slice preparation of the olfactory bulb, we found that evoked neural activity in Kv1.3-expressing mitral cells is enhanced following acute insulin application. Insulin mediated changes in mitral cell excitability are predominantly due to the modulation of Kv1.3 channels as evidenced by the lack of effect in slices from Kv1.3-null mice. Moreover, a selective Kv1.3 peptide blocker (ShK186 inhibits more than 80% of the outward current in parallel voltage-clamp studies, whereby insulin significantly decreases the peak current magnitude without altering the kinetics of inactivation or deactivation. Mice that were chronically administered insulin using intranasal delivery approaches exhibited either an elevation in basal firing frequency or fired a single cluster of action potentials. Following chronic administration of the hormone, mitral cells were inhibited by application of acute insulin rather than excited. Mice made obese through a diet of ∼32% fat exhibited prominent changes in mitral cell action potential shape and clustering behavior, whereby the subsequent response to acute insulin stimulation was either attenuated or completely absent. Our results implicate an inappropriate neural function of olfactory sensors following exposure to

  3. Fetal alcohol exposure leads to abnormal olfactory bulb development and impaired odor discrimination in adult mice

    NARCIS (Netherlands)

    K.G. Akers (Katherine); S.A. Kushner (Steven); A.T. Leslie (Ana); L. Clarke (Laura); D. van der Kooy (Derek); J.P. Lerch (Jason); P.W. Frankland (Paul)

    2011-01-01

    textabstractBackground: Children whose mothers consumed alcohol during pregnancy exhibit widespread brain abnormalities and a complex array of behavioral disturbances. Here, we used a mouse model of fetal alcohol exposure to investigate relationships between brain abnormalities and specific

  4. Acute Immobilization Stress Modulate GABA Release from Rat Olfactory Bulb: Involvement of Endocannabinoids—Cannabinoids and Acute Stress Modulate GABA Release

    Directory of Open Access Journals (Sweden)

    Alejandra Delgado

    2011-01-01

    Full Text Available We studied the effects of cannabinoids and acute immobilization stress on the regulation of GABA release in the olfactory bulb. Glutamate-stimulated 3H-GABA release was measured in superfused slices. We report that cannabinoids as WIN55, 212-2, methanandamide, and 2-arachidonoylglycerol were able to inhibit glutamate- and KCl-stimulated 3H-GABA release. This effect was blocked by the CB1 antagonist AM281. On the other hand, acute stress was able per se to increase endocannabinoid activity. This effect was evident since the inhibition of stimulated GABA release by acute stress was reversed with AM281 and tetrahydrolipstatin. Inhibition of the endocannabinoid transport or its catabolism showed reduction of GABA release, antagonized by AM281 in control and stressed animals. These results point to endocannabinoids as inhibitory modulators of GABA release in the olfactory bulb acting through an autocrine mechanism. Apparently, stress increases the endocannabinoid system, modulating GABAergic synaptic function in a primary sensory organ.

  5. The terminal nerve plays a prominent role in GnRH-1 neuronal migration independent from proper olfactory and vomeronasal connections to the olfactory bulbs

    Directory of Open Access Journals (Sweden)

    Ed Zandro M. Taroc

    2017-10-01

    Yoshihara et al., 2005. Our data prove that correct development of the OBs and axonal connection of the olfactory/vomeronasal sensory neurons to the forebrain are not required for GnRH-1 ns migration, and suggest that the terminal nerve, which forms the GnRH-1 migratory scaffold, follows different guidance cues and differs in gene expression from olfactory/vomeronasal sensory neurons.

  6. Modeling peripheral olfactory coding in Drosophila larvae.

    Directory of Open Access Journals (Sweden)

    Derek J Hoare

    Full Text Available The Drosophila larva possesses just 21 unique and identifiable pairs of olfactory sensory neurons (OSNs, enabling investigation of the contribution of individual OSN classes to the peripheral olfactory code. We combined electrophysiological and computational modeling to explore the nature of the peripheral olfactory code in situ. We recorded firing responses of 19/21 OSNs to a panel of 19 odors. This was achieved by creating larvae expressing just one functioning class of odorant receptor, and hence OSN. Odor response profiles of each OSN class were highly specific and unique. However many OSN-odor pairs yielded variable responses, some of which were statistically indistinguishable from background activity. We used these electrophysiological data, incorporating both responses and spontaneous firing activity, to develop a bayesian decoding model of olfactory processing. The model was able to accurately predict odor identity from raw OSN responses; prediction accuracy ranged from 12%-77% (mean for all odors 45.2% but was always significantly above chance (5.6%. However, there was no correlation between prediction accuracy for a given odor and the strength of responses of wild-type larvae to the same odor in a behavioral assay. We also used the model to predict the ability of the code to discriminate between pairs of odors. Some of these predictions were supported in a behavioral discrimination (masking assay but others were not. We conclude that our model of the peripheral code represents basic features of odor detection and discrimination, yielding insights into the information available to higher processing structures in the brain.

  7. Inhibition of Inflammation-Associated Olfactory Loss by Etanercept in an Inducible Olfactory Inflammation Mouse Model.

    Science.gov (United States)

    Jung, Yong Gi; Lane, Andrew P

    2016-06-01

    To determine the effect of a soluble human tumor necrosis factor alpha (TNF-α) receptor blocker (etanercept) on an inducible olfactory inflammation (IOI) mouse model. An in vivo study using a transgenic mouse model. Research laboratory. To study the impact of chronic inflammation on the olfactory system, a transgenic mouse model of chronic rhinosinusitis-associated olfactory loss was utilized (IOI mouse), expressing TNF-α in a temporally controlled fashion within the olfactory epithelium. In one group of mice (n = 4), etanercept was injected intraperitoneally (100 μg/dose, 3 times/week) concurrent with a 2-week period of TNF-α expression. A second group of mice (n = 2) underwent induction of TNF-α expression for 8 weeks, with etanercept treatment administered during the final 2 weeks of inflammation. Olfactory function was assayed by elecro-olfactogram (EOG), and olfactory tissue was processed for histology and immunohistochemical staining. Each group was compared with an equal-number control group. Compared with nontreated IOI mice, etanercept-treated IOI mice showed significantly improved EOG responses after 2 weeks (P loss of olfactory epithelium and no EOG response in nontreated IOI mice. However, in etanercept-treated mice, regeneration of olfactory epithelium was observed. Concomitant administration of etanercept in IOI mice results in interruption of TNF-α-induced olfactory loss and induction of neuroepithelial regeneration. This demonstrates that etanercept has potential utility as a tool for elucidating the role of TNF-α in other olfactory inflammation models. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2016.

  8. [Development of the Human Olfactory Bulbs in the Prenatal Ontogenesis: an Immunochistochemical Study with Markers of Presynaptic Terminals (anti-SNAP-25, -Synapsin-I, -Synaptophysin)].

    Science.gov (United States)

    Kharlamova, A S; Barabanov, V M; Saveliev, S V

    2015-01-01

    We provide the data of the olfactory bulbs (OB) development in the human fetuses on the stages from 8 week to birth. Immunochistochemical markers of presynaptic terminals (anti-SNAP-25, -synapsin-I, -synaptophysin) were used to evaluate the maturation of the OB. Differentiation of the OB layers begins from periphery, which implicitly evidences that growth of the olfactory nerves fibers induses not only anatomical differentiation of the OB, but also differentiation of its functional layers. The sites of the developing glomerulus are revealed using the immunochistochemical prosedure on the stage before distinct glomerulus can be identified with common histological procedure. OB conductive system demonstrates immunoreactivity with the antibodies to the presynaptic proteins on the all stages from 10-11 weeks of fetus development. Four stages of the OB development are described. All functional layers of the OB are mature at the 22-weeks stage. Further differentiation of the OB neuroblasts, including lamina formation of the internal granular leyer, glomerular layer development, OB growth continue after 20-22 weeks stage until 38-40 weeks of the fetus develoment. Patterns of the immunoreactivity with antibodies to SNAP-25, synapsin-I and synaptophysin are completely appropriate to those of adult's OB on the 38-40 weeks of the prenatal development. Complete maturity of the human OB is achived at 38-40 weeks of the prenatal development.

  9. Sniff-Like Patterned Input Results in Long-Term Plasticity at the Rat Olfactory Bulb Mitral and Tufted Cell to Granule Cell Synapse

    Directory of Open Access Journals (Sweden)

    Mahua Chatterjee

    2016-01-01

    Full Text Available During odor sensing the activity of principal neurons of the mammalian olfactory bulb, the mitral and tufted cells (MTCs, occurs in repetitive bursts that are synchronized to respiration, reminiscent of hippocampal theta-gamma coupling. Axonless granule cells (GCs mediate self- and lateral inhibitory interactions between the excitatory MTCs via reciprocal dendrodendritic synapses. We have explored long-term plasticity at this synapse by using a theta burst stimulation (TBS protocol and variations thereof. GCs were excited via glomerular stimulation in acute brain slices. We find that TBS induces exclusively long-term depression in the majority of experiments, whereas single bursts (“single-sniff paradigm” can elicit both long-term potentiation and depression. Statistical analysis predicts that the mechanism underlying this bidirectional plasticity involves the proportional addition or removal of presynaptic release sites. Gamma stimulation with the same number of APs as in TBS was less efficient in inducing plasticity. Both TBS- and “single-sniff paradigm”-induced plasticity depend on NMDA receptor activation. Since the onset of plasticity is very rapid and requires little extra activity, we propose that these forms of plasticity might play a role already during an ongoing search for odor sources. Our results imply that components of both short-term and long-term olfactory memory may be encoded at this synapse.

  10. Olfactory bulb short axon cell release of GABA and dopamine produces a temporally biphasic inhibition-excitation response in external tufted cells.

    Science.gov (United States)

    Liu, Shaolin; Plachez, Celine; Shao, Zuoyi; Puche, Adam; Shipley, Michael T

    2013-02-13

    Evidence for coexpression of two or more classic neurotransmitters in neurons has increased, but less is known about cotransmission. Ventral tegmental area (VTA) neurons corelease dopamine (DA), the excitatory transmitter glutamate, and the inhibitory transmitter GABA onto target cells in the striatum. Olfactory bulb (OB) short axon cells (SACs) form interglomerular connections and coexpress markers for DA and GABA. Using an optogenetic approach, we provide evidence that mouse OB SACs release both GABA and DA onto external tufted cells (ETCs) in other glomeruli. Optical activation of channelrhodopsin specifically expressed in DAergic SACs produced a GABA(A) receptor-mediated monosynaptic inhibitory response, followed by DA-D(1)-like receptor-mediated excitatory response in ETCs. The GABA(A) receptor-mediated hyperpolarization activates I(h) current in ETCs; synaptically released DA increases I(h), which enhances postinhibitory rebound spiking. Thus, the opposing actions of synaptically released GABA and DA are functionally integrated by I(h) to generate an inhibition-to-excitation "switch" in ETCs. Consistent with the established role of I(h) in ETC burst firing, we show that endogenous DA release increases ETC spontaneous bursting frequency. ETCs transmit sensory signals to mitral/tufted output neurons and drive intraglomerular inhibition to shape glomerulus output to downstream olfactory networks. GABA and DA cotransmission from SACs to ETCs may play a key role in regulating output coding across the glomerular array.

  11. Microglia and their CX3CR1 signaling are involved in hippocampal- but not olfactory bulb-related memory and neurogenesis.

    Science.gov (United States)

    Reshef, Ronen; Kreisel, Tirzah; Beroukhim Kay, Dorsa; Yirmiya, Raz

    2014-10-01

    Recent studies demonstrate that microglia play an important role in cognitive and neuroplasticity processes, at least partly via microglial CX3C receptor 1 (CX3CR1) signaling. Furthermore, microglia are responsive to environmental enrichment (EE), which modulates learning, memory and neurogenesis. In the present study we examined the role of microglial CX3CR1 signaling in hippocampal- and olfactory-bulb (OB)-related memory and neurogenesis in homozygous mice with microglia-specific transgenic expression of GFP under the CX3CR1 promoter (CX3CR1(-/-) mice), in which the CX3CR1 gene is functionally deleted, as well as heterozygous CX3CR1(+/-) and WT controls. We report that the CX3CR1-deficient mice displayed better hippocampal-dependent memory functioning and olfactory recognition, along with increased number and soma size of hippocampal microglia, suggestive of mild activation status, but no changes in OB microglia. A similar increase in hippocampal-dependent memory functioning and microglia number was also induced by pharmacological inhibition of CX3CR1 signaling, using chronic (2weeks) i.c.v. administration of CX3CR1 blocking antibody. In control mice, EE improved hippocampal-dependent memory and neurogenesis, and increased hippocampal microglia number and soma size, whereas odor enrichment (OE) improved olfactory recognition and OB neurogenesis without changing OB microglia status. In CX3CR1-deficient mice, EE and OE did not produce any further improvement in memory functioning or neurogenesis and had no effect on microglial status. These results support the notion that in the hippocampus microglia and their interactions with neurons via the CX3CR1 play an important role in memory functioning and neurogenesis, whereas in the OB microglia do not seem to be involved in these processes. Copyright © 2014 Elsevier Inc. All rights reserved.

  12. Modulation of Olfactory Bulb Network Activity by Serotonin: Synchronous Inhibition of Mitral Cells Mediated by Spatially Localized GABAergic Microcircuits

    Science.gov (United States)

    Schmidt, Loren J.; Strowbridge, Ben W.

    2014-01-01

    Although inhibition has often been proposed as a central mechanism for coordinating activity in the olfactory system, relatively little is known about how activation of different inhibitory local circuit pathways can generate coincident inhibition of principal cells. We used serotonin (5-HT) as a pharmacological tool to induce spiking in ensembles…

  13. Odor discrimination learning in the Indian greater short-nosed fruit bat (Cynopterus sphinx): differential expression of Egr-1, C-fos and PP-1 in the olfactory bulb, amygdala and hippocampus.

    Science.gov (United States)

    Mukilan, Murugan; Bogdanowicz, Wieslaw; Marimuthu, Ganapathy; Rajan, Koilmani Emmanuvel

    2018-04-19

    Activity-dependent expression of immediate-early genes (IEGs) is induced by exposure to odor. The present study was designed to investigate whether there is differential expression of IEGs ( Egr-1 , C-fos ) in the brain region mediating olfactory memory in the Indian greater short-nosed fruit bat Cynopterus sphinx We assumed that differential expression of IEGs in different brain regions may orchestrate a preference odor (PO) and aversive odor (AO) memory in C. sphinx We used preferred (0.8% wt/wt of cinnamon powder) and aversive (0.4% wt/vol of citral) odor substances, with freshly-prepared chopped apple, to assess the behavioural response and induction of IEGs in the olfactory bulb, hippocampus and amygdala. After experiencing PO and AO, the bats initially responded to both, later only engaging in feeding bouts in response to the PO food. The expression pattern of Egr-1 and C-fos in the olfactory bulb, hippocampus and amygdala was similar at different time points (15, 30 and 60 min) following the response to PO, but different for AO. The response to AO elevated the level of C-fos expression within 30 min and reduced it at 60 min in both the olfactory bulb and the hippocampus, as opposed to the continuous increase noted in the amygdala. In addition, we tested whether an epigenetic mechanism entailing protein phosphatase-1 (PP-1) acts on IEG expression. The observed PP-1 expression and the level of unmethylated/methylated promoter revealed that the C-fos expression is possibly controlled by an odor-mediated regulation of PP-1. These results in turn imply that the differential expression of C-fos in the hippocampus and amygdala may contribute to olfactory learning and memory in C. sphinx . © 2018. Published by The Company of Biologists Ltd.

  14. Cytological organization of the alpha component of the anterior olfactory nucleus and olfactory limbus

    Directory of Open Access Journals (Sweden)

    Jorge A Larriva-Sahd

    2012-06-01

    Full Text Available This study describes the microscopic organization of a wedge-shaped area at the intersection of the main and accessory olfactory bulbs, or olfactory limbus , and an additional component of the anterior olfactory nucleus or alpha accessory olfactory bulb that lies underneath of the accessory olfactory bulb. The olfactory limbus consists of a modified bulbar cortex bounded anteriorly by the main olfactory bulb and posteriorly by the accessory olfactory bulb. In Nissl-stained specimens the olfactory limbus differs from the main olfactory bulb by a progressive, antero-posterior decrease in thickness or absence of the external plexiform, mitral/tufted cell, and granule cell layers. On cytoarchitectual grounds the olfactory limbus is divided from rostral to caudal into three distinct components: a stripe of glomerular-free cortex or preolfactory area, a second or necklace glomerular area, and a wedge-shaped or interstitial area crowned by the so-called modified glomeruli that appear to belong to the anterior accessory olfactory bulb. The strategic location and interactions with the main and accessory olfactory bulbs, together with the previously noted functional and connectional evidence, suggest that the olfactory limbus may be related to both sensory modalities. The alpha component of the anterior olfactory nucleus, a slender cellular cluster (i.e., 650 x 150 µm paralleling the base of the accessory olfactory bulb, contains two neuron types: a pyramidal-like neuron and an interneuron. Dendrites of pyramidal-like cells organize into a single bundle that ascends avoiding the accessory olfactory bulb to resolve in a trigone bounded by the edge of the olfactory limbus, the accessory olfactory bulb and the dorsal part of the anterior olfactory nucleus. Utrastructurally, the neuropil of the alpha component contains three types of synaptic terminals; one of them immunoreactive to the enzyme glutamate decarboxylase, isoform 67.

  15. Polyurethane/polylactide-based biomaterials combined with rat olfactory bulb-derived glial cells and adipose-derived mesenchymal stromal cells for neural regenerative medicine applications.

    Science.gov (United States)

    Grzesiak, Jakub; Marycz, Krzysztof; Szarek, Dariusz; Bednarz, Paulina; Laska, Jadwiga

    2015-01-01

    Research concerning the elaboration and application of biomaterial which may support the nerve tissue regeneration is currently one of the most promising directions. Biocompatible polymer devices are noteworthy group among the numerous types of potentially attractive biomaterials for regenerative medicine application. Polylactides and polyurethanes may be utilized for developing devices for supporting the nerve regeneration, like nerve guide conduits or bridges connecting the endings of broken nerve tracts. Moreover, the combination of these biomaterial devices with regenerative cell populations, like stem or precursor cells should significantly improve the final therapeutic effect. Therefore, the composition and structure of final device should support the proper adhesion and growth of cells destined for clinical application. In current research, the three polymer mats elaborated for connecting the broken nerve tracts, made from polylactide, polyurethane and their blend were evaluated both for physical properties and in vitro, using the olfactory-bulb glial cells and mesenchymal stem cells. The evaluation of Young's modulus, wettability and roughness of obtained materials showed the differences between analyzed samples. The analysis of cell adhesion, proliferation and morphology showed that the polyurethane-polylactide blend was the most neutral for cells in culture, while in the pure polymer samples there were significant alterations observed. Our results indicated that polyurethane-polylactide blend is an optimal composition for culturing and delivery of glial and mesenchymal stem cells. Copyright © 2015. Published by Elsevier B.V.

  16. In vivo layer visualization of rat olfactory bulb by a swept source optical coherence tomography and its confirmation through electrocoagulation and anatomy

    Science.gov (United States)

    Watanabe, Hideyuki; Rajagopalan, Uma Maheswari; Nakamichi, Yu; Igarashi, Kei M.; Madjarova, Violeta Dimitrova; Kadono, Hirofumi; Tanifuji, Manabu

    2011-01-01

    Here, we report in vivo 3-D visualization of the layered organization of a rat olfactory bulb (OB) by a swept source optical coherence tomography (SS-OCT). The SS-OCT operates at a wavelength of 1334 nm with respective theoretical depth and lateral resolutions of 6.7 μm and 15.4 μm in air and hence it is possible to get a 3D structural map of OB in vivo at the micron level resolution with millimeter-scale imaging depth. Up until now, with methods such as MRI, confocal microscopy, OB depth structure in vivo had not been clearly visualized as these do not satisfy the criterion of simultaneously providing micron-scale spatial resolution and imaging up to a few millimeter in depth. In order to confirm the OB’s layered organization revealed by SS-OCT, we introduced the technique of electrocoagulation to make landmarks across the layered structure. To our knowledge this is such a first study that combines electrocoagulation and OCT in vivo of rat OB. Our results confirmed the layered organization of OB, and moreover the layers were clearly identified by electrocoagulation landmarks both in the OCT structural and anatomical slice images. We expect such a combined study is beneficial for both OCT and neuroscience fields. PMID:21833364

  17. Intracranial dialysis measurement of oxytocin, monoamine and uric acid release from the olfactory bulb and substantia nigra of sheep during parturition, suckling, separation from lambs and eating.

    Science.gov (United States)

    Kendrick, K M; Keverne, E B; Chapman, C; Baldwin, B A

    1988-01-26

    Intracranial dialysis was used to measure the release of oxytocin (OXY), monoamines and their metabolites and uric acid (UA) from the substantia nigra (SN) and olfactory bulb (OB) of sheep during parturition, suckling, separation from lambs and eating. Results showed that OXY concentrations increased significantly during parturition, suckling and eating in the SN and during parturition and suckling in the OB. Concentrations of dopamine (DA) increased significantly in the SN during suckling and eating and in the OB during parturition and suckling. The dopamine metabolite, homovanillic acid, also increased significantly in the SN during parturition. Concentrations of the noradrenaline metabolite, 4-hydroxy-3-methoxyphenylethan-1,2-diol (MHPG) and the purine metabolite, UA, were significantly raised during parturition, suckling and separation from the lambs in the SN and increased UA levels were also found during eating. In a separate experiment it was confirmed that OXY was detectable in homogenates of both the SN and the OB. These results show that, in the sheep, OXY and DA release in the SN is associated with maternal and ingestive behaviour whereas similar release in the OB may only be related to maternal behaviour. Release of MHPG in the SN may be associated with maternal behaviour and/or stress.

  18. The Impact of Oxidative Stress Factors on the Viability, Senescence, and Methylation Status of Olfactory Bulb-Derived Glial Cells Isolated from Human Cadaver Donors.

    Science.gov (United States)

    Marycz, Krzysztof; Kornicka, Katarzyna; Grzesiak, Jakub; Tomaszewski, Krzysztof A; Szarek, Dariusz; Kopacz, Paweł

    2017-01-01

    The olfactory bulb (OB) is a unique structure in the central nervous system that retains the ability to create new neuronal connections. Glial cells isolated from the OB have been recently considered as a novel and promising tool to establish an effective therapy for central nervous system injuries. Due to the hindered access to autologous tissue for cell isolation, an allogeneic source of tissues obtained postmortem has been proposed. In this study, we focused on the morphological and molecular characteristics of human OB-derived glial cells isolated postmortem, at different time points after a donor's death. We evaluated the proliferative activity of the isolated cells, and investigated the ultrastructure of the mitochondria, the accumulation of intracellular reactive oxygen species, and the activity of superoxide dismutase. The data obtained clearly indicate that the duration of ischemia is crucial for the viability/senescence rate of OB-derived glial cells. The OB can be isolated during autopsy and still stand as a source of viable glial cells, but ischemia duration is a major factor limiting its potential usefulness in therapies. © 2017 S. Karger AG, Basel.

  19. The Beneficial Impact of Antidepressant Drugs on Prenatal Stress-Evoked Malfunction of the Insulin-Like Growth Factor-1 (IGF-1) Protein Family in the Olfactory Bulbs of Adult Rats.

    Science.gov (United States)

    Trojan, Ewa; Głombik, Katarzyna; Ślusarczyk, Joanna; Budziszewska, Bogusława; Kubera, Marta; Roman, Adam; Lasoń, Władysław; Basta-Kaim, Agnieszka

    2016-02-01

    Insulin-like growth factor-1 (IGF-1) promotes the growth, differentiation, and survival of both neurons and glial cells, and it is believed to exert antidepressant-like activity. Thus, disturbances in the IGF-1 system could be responsible for the course of depression. To date, there have been no papers showing the impact of chronic antidepressant treatment on the IGF-1 network in the olfactory bulb (OB) in an animal model of depression. Prenatal stress was used as model of depression. Twenty-four 3-month-old male offspring of control and stressed mothers were subjected to behavioral testing (forced swim test). The mRNA expression of IGF-1 and IGF-1 receptor (IGF-1R) and the protein level of IGF-1 and its phosphorylation, as well as the concentrations of IGF-binding proteins (IGFBP-2, -4, -3, and -6), were measured in OBs before and after chronic imipramine, fluoxetine, or tianeptine administration. Adult rats exposed prenatally to stressful stimuli displayed not only depression-like behavior but also decreased IGF-1 expression, dysregulation in the IGFBP network, and diminished mRNA expression, as well as IGF-1R phosphorylation, in the OB. The administration of antidepressants normalized most of the changes in the IGF-1 system of the OB evoked by prenatal stress. These results suggested a beneficial effect of chronic antidepressant drug treatment in the alleviation of IGF-1 family malfunction in OBs in an animal model of depression.

  20. THREE-DIMENSIONAL RECONSTRUCTION OF THE ANTERIOR OLFACTORY NUCLEUS IN THE HUMAN OLFACTORY BULB AND PEDUNCLE. Reconstrucción tridimiensional del núcleo olfatorio anterior en el bulbo y pedúnculo olfatorio humano

    Directory of Open Access Journals (Sweden)

    Steven Berendsen

    2016-03-01

    Full Text Available El bulbo y pedúnculo olfatorio humano contienen muchos grupos celulares más o menos separados que habitualmente son considerados como parte del núcleo olfatorio anterior retro-bulbar (AON. La presunción que estos grupos celulares sean considerados como extensión rostral del AON en el hemisferio rostral retrocede a la descripción de un único caso por Crosby y Humphrey (1941. Para mejorar nuestra comprensión de la anatomía del AON bulbar y peduncular humano investigamos la morfología, forma y tamaño de estas partes en este núcleo en tejido post-mortem de individuos de edades conocidas. Se obtuvieron seis bulbos y pedúnculos olfatorios, incluyendo la sustancia perforada anterior (SPA, de cerebros donados; se realizaron cortes seriales horizontales a 40µm y se tiñó con substancia de Nissl. Las neuronas de tamaño mediano a grande de esta parte del AON se tiñeron intensamente y tenían un diámetro promedio de 16µm. La reconstruc-ción tridimensional demostró que en todos los casos, excepto uno, el AON bulbar y peduncular consistieron en una cadena discontinua de grupos celulares conectados por puentes de neuropilas pobres o libres de células. El número de grupos celulares y de puentes conectores difiere en cada individuo. Concluimos que las porciones bulbar y peduncular del AON humano debería ser considerado como una especialización humana más que como una extensión rostral del área AON retro-bulbar. Esto es acorde con las propiedades neuro-clínicas previamente publicadas y la degeneración temprana selectiva, pre-clínica, de estos nichos celulares en la enfermedad neuro-degenerativa. The human olfactory bulb and peduncle contain several more or less separated cell groups that are usually regarded to be part of the retrobulbar anterior olfactory nucleus (AON. The assumption that these cell groups are to be considered as the rostral extension of the AON in the rostral hemisphere goes back to the description of one single

  1. models of hourly dry bulb temperature and relative humidity of key

    African Journals Online (AJOL)

    user

    3: Worst cases of MFE for Dry bulb temperature and Relative humidity. Fig. 4: Best cases of ... the Second Joint International Conference of. University of Ilorin, Ilorin, Nigeria and University ... Erbs, D. G., “Models and Applications for Weather.

  2. Nutritional status modulates behavioural and olfactory bulb Fos responses to isoamyl acetate or food odour in rats: roles of orexins and leptin.

    Science.gov (United States)

    Prud'homme, M J; Lacroix, M C; Badonnel, K; Gougis, S; Baly, C; Salesse, R; Caillol, M

    2009-09-15

    Food odours are major determinants for food choice, and their detection depends on nutritional status. The effects of different odour stimuli on both behavioural responses (locomotor activity and sniffing) and Fos induction in olfactory bulbs (OB) were studied in satiated or 48-h fasted rats. We focused on two odour stimuli: isoamyl acetate (ISO), as a neutral stimulus either unknown or familiar, and food pellet odour, that were presented to quiet rats during the light phase of the day. We found significant effects of nutritional status and odour stimulus on both behavioural and OB responses. The locomotor activity induced by odour stimuli was always more marked in fasted than in satiated rats, and food odour induced increased sniffing activity only in fasted rats. Fos expression was quantified in periglomerular, mitral and granular OB cell layers. As a new odour, ISO induced a significant increase in Fos expression in all OB layers, similar in fasted and satiated rats. Significant OB responses to familiar odours were only observed in fasted rats. Among the numerous peptides shown to vary after 48 h of fasting, we focused on orexins (for which immunoreactive fibres are present in the OB) and leptin, as a peripheral hormone linked to adiposity, and tested their effects of food odour. The administration of orexin A in satiated animals partially mimicked fasting, since food odour increased OB Fos responses, but did not induce sniffing. The treatment of fasted animals with either an orexin receptors antagonist (ACT-078573) or leptin significantly decreased both locomotor activity, time spent sniffing food odour and OB Fos induction in all cell layers, thus mimicking a satiated status. We conclude that orexins and leptin are some of the factors that can modify behavioural and OB Fos responses to a familiar food odour.

  3. Polyurethane/polylactide-based biomaterials combined with rat olfactory bulb-derived glial cells and adipose-derived mesenchymal stromal cells for neural regenerative medicine applications

    Energy Technology Data Exchange (ETDEWEB)

    Grzesiak, Jakub, E-mail: grzesiak.kuba@gmail.com [Electron Microscopy Laboratory, University of Environmental and Life Sciences, Kozuchowska 5b, 51-631 Wroclaw (Poland); Marycz, Krzysztof [Electron Microscopy Laboratory, University of Environmental and Life Sciences, Kozuchowska 5b, 51-631 Wroclaw (Poland); Szarek, Dariusz [Department of Neurosurgery, Lower Silesia Specialist Hospital of T. Marciniak, Emergency Medicine Center, Traugutta 116, 50-420 Wroclaw (Poland); Bednarz, Paulina [State Higher Vocational School in Tarnów, Mickiewicza 8, 33-100 Tarnów (Poland); Laska, Jadwiga [AGH University of Science and Technology, Faculty of Materials Science and Ceramics, Mickiewicza 30, 30-059 Kraków (Poland)

    2015-07-01

    Research concerning the elaboration and application of biomaterial which may support the nerve tissue regeneration is currently one of the most promising directions. Biocompatible polymer devices are noteworthy group among the numerous types of potentially attractive biomaterials for regenerative medicine application. Polylactides and polyurethanes may be utilized for developing devices for supporting the nerve regeneration, like nerve guide conduits or bridges connecting the endings of broken nerve tracts. Moreover, the combination of these biomaterial devices with regenerative cell populations, like stem or precursor cells should significantly improve the final therapeutic effect. Therefore, the composition and structure of final device should support the proper adhesion and growth of cells destined for clinical application. In current research, the three polymer mats elaborated for connecting the broken nerve tracts, made from polylactide, polyurethane and their blend were evaluated both for physical properties and in vitro, using the olfactory-bulb glial cells and mesenchymal stem cells. The evaluation of Young's modulus, wettability and roughness of obtained materials showed the differences between analyzed samples. The analysis of cell adhesion, proliferation and morphology showed that the polyurethane–polylactide blend was the most neutral for cells in culture, while in the pure polymer samples there were significant alterations observed. Our results indicated that polyurethane–polylactide blend is an optimal composition for culturing and delivery of glial and mesenchymal stem cells. - Highlights: • Polyurethane–polylactide blends exhibit different characteristics from pure polymers. • Pure PU and PLA negatively influence on morphology of glial and mesenchymal cells. • PU/PLA blend was neutral for glial and mesenchymal cell proliferation and morphology.

  4. Polyurethane/polylactide-based biomaterials combined with rat olfactory bulb-derived glial cells and adipose-derived mesenchymal stromal cells for neural regenerative medicine applications

    International Nuclear Information System (INIS)

    Grzesiak, Jakub; Marycz, Krzysztof; Szarek, Dariusz; Bednarz, Paulina; Laska, Jadwiga

    2015-01-01

    Research concerning the elaboration and application of biomaterial which may support the nerve tissue regeneration is currently one of the most promising directions. Biocompatible polymer devices are noteworthy group among the numerous types of potentially attractive biomaterials for regenerative medicine application. Polylactides and polyurethanes may be utilized for developing devices for supporting the nerve regeneration, like nerve guide conduits or bridges connecting the endings of broken nerve tracts. Moreover, the combination of these biomaterial devices with regenerative cell populations, like stem or precursor cells should significantly improve the final therapeutic effect. Therefore, the composition and structure of final device should support the proper adhesion and growth of cells destined for clinical application. In current research, the three polymer mats elaborated for connecting the broken nerve tracts, made from polylactide, polyurethane and their blend were evaluated both for physical properties and in vitro, using the olfactory-bulb glial cells and mesenchymal stem cells. The evaluation of Young's modulus, wettability and roughness of obtained materials showed the differences between analyzed samples. The analysis of cell adhesion, proliferation and morphology showed that the polyurethane–polylactide blend was the most neutral for cells in culture, while in the pure polymer samples there were significant alterations observed. Our results indicated that polyurethane–polylactide blend is an optimal composition for culturing and delivery of glial and mesenchymal stem cells. - Highlights: • Polyurethane–polylactide blends exhibit different characteristics from pure polymers. • Pure PU and PLA negatively influence on morphology of glial and mesenchymal cells. • PU/PLA blend was neutral for glial and mesenchymal cell proliferation and morphology

  5. Lineage analysis of quiescent regenerative stem cells in the adult brain by genetic labelling reveals spatially restricted neurogenic niches in the olfactory bulb.

    Science.gov (United States)

    Giachino, Claudio; Taylor, Verdon

    2009-07-01

    The subventricular zone (SVZ) of the lateral ventricles is the major neurogenic region in the adult mammalian brain, harbouring neural stem cells within defined niches. The identity of these stem cells and the factors regulating their fate are poorly understood. We have genetically mapped a population of Nestin-expressing cells during postnatal development to study their potential and fate in vivo. Taking advantage of the recombination characteristics of a nestin::CreER(T2) allele, we followed a subpopulation of neural stem cells and traced their fate in a largely unrecombined neurogenic niche. Perinatal nestin::CreER(T2)-expressing cells give rise to multiple glial cell types and neurons, as well as to stem cells of the adult SVZ. In the adult SVZ nestin::CreER(T2)-expressing neural stem cells give rise to several neuronal subtypes in the olfactory bulb (OB). We addressed whether the same population of neural stem cells play a role in SVZ regeneration. Following anti-mitotic treatment to eliminate rapidly dividing progenitors, relatively quiescent nestin::CreER(T2)-targeted cells are spared and contribute to SVZ regeneration, generating new proliferating precursors and neuroblasts. Finally, we have identified neurogenic progenitors clustered in ependymal-like niches within the rostral migratory stream (RMS) of the OB. These OB-RMS progenitors generate neuroblasts that, upon transplantation, graft, migrate and differentiate into granule and glomerular neurons. In summary, using conditional lineage tracing we have identified neonatal cells that are the source of neurogenic and regenerative neural stem cells in the adult SVZ and occupy a novel neurogenic niche in the OB.

  6. Chronic Blockade of Brain Endothelin Receptor Type-A (ETA Reduces Blood Pressure and Prevents Catecholaminergic Overactivity in the Right Olfactory Bulb of DOCA-Salt Hypertensive Rats

    Directory of Open Access Journals (Sweden)

    Luis R. Cassinotti

    2018-02-01

    Full Text Available Overactivity of the sympathetic nervous system and central endothelins (ETs are involved in the development of hypertension. Besides the well-known brain structures involved in the regulation of blood pressure like the hypothalamus or locus coeruleus, evidence suggests that the olfactory bulb (OB also modulates cardiovascular function. In the present study, we evaluated the interaction between the endothelinergic and catecholaminergic systems in the OB of deoxycorticosterone acetate (DOCA-salt hypertensive rats. Following brain ET receptor type A (ETA blockade by BQ610 (selective antagonist, transcriptional, traductional, and post-traductional changes in tyrosine hydroxylase (TH were assessed in the OB of normotensive and DOCA-salt hypertensive rats. Time course variations in systolic blood pressure and heart rate were also registered. Results showed that ETA blockade dose dependently reduced blood pressure in hypertensive rats, but it did not change heart rate. It also prevented the increase in TH activity and expression (mRNA and protein in the right OB of hypertensive animals. However, ETA blockade did not affect hemodynamics or TH in normotensive animals. Present results support that brain ETA are not involved in blood pressure regulation in normal rats, but they significantly contribute to chronic blood pressure elevation in hypertensive animals. Changes in TH activity and expression were observed in the right but not in the left OB, supporting functional asymmetry, in line with previous studies regarding cardiovascular regulation. Present findings provide further evidence on the role of ETs in the regulation of catecholaminergic activity and the contribution of the right OB to DOCA-salt hypertension.

  7. Chronic Blockade of Brain Endothelin Receptor Type-A (ETA) Reduces Blood Pressure and Prevents Catecholaminergic Overactivity in the Right Olfactory Bulb of DOCA-Salt Hypertensive Rats.

    Science.gov (United States)

    Cassinotti, Luis R; Guil, María J; Schöller, Mercedes I; Navarro, Mónica P; Bianciotti, Liliana G; Vatta, Marcelo S

    2018-02-27

    Overactivity of the sympathetic nervous system and central endothelins (ETs) are involved in the development of hypertension. Besides the well-known brain structures involved in the regulation of blood pressure like the hypothalamus or locus coeruleus, evidence suggests that the olfactory bulb (OB) also modulates cardiovascular function. In the present study, we evaluated the interaction between the endothelinergic and catecholaminergic systems in the OB of deoxycorticosterone acetate (DOCA)-salt hypertensive rats. Following brain ET receptor type A (ET A ) blockade by BQ610 (selective antagonist), transcriptional, traductional, and post-traductional changes in tyrosine hydroxylase (TH) were assessed in the OB of normotensive and DOCA-salt hypertensive rats. Time course variations in systolic blood pressure and heart rate were also registered. Results showed that ET A blockade dose dependently reduced blood pressure in hypertensive rats, but it did not change heart rate. It also prevented the increase in TH activity and expression (mRNA and protein) in the right OB of hypertensive animals. However, ET A blockade did not affect hemodynamics or TH in normotensive animals. Present results support that brain ET A are not involved in blood pressure regulation in normal rats, but they significantly contribute to chronic blood pressure elevation in hypertensive animals. Changes in TH activity and expression were observed in the right but not in the left OB, supporting functional asymmetry, in line with previous studies regarding cardiovascular regulation. Present findings provide further evidence on the role of ETs in the regulation of catecholaminergic activity and the contribution of the right OB to DOCA-salt hypertension.

  8. Olfactory Dysfunctions and Decreased Nitric Oxide Production in the Brain of Human P301L Tau Transgenic Mice.

    Science.gov (United States)

    Hu, Yang; Ding, Wenting; Zhu, Xiaonan; Chen, Ruzhu; Wang, Xuelan

    2016-04-01

    Different patterns of olfactory dysfunction have been found in both patients and mouse models of Alzheimer's Disease. However, the underlying mechanism of the dysfunction remained unknown. Deficits of nitric oxide production in brain can cause olfactory dysfunction by preventing the formation of olfactory memory. The aim of this study was to investigate the behavioral changes in olfaction and alterations in metabolites of nitric oxide, nitrate/nitrite concentration, in the brain of human P301L tau transgenic mice. The tau mice showed impairments in olfaction and increased abnormal phosphorylation of Tau protein at AT8 in different brain areas, especially in olfactory bulb. We now report that these olfactory deficits and Tau pathological changes were accompanied by decreased nitrate/nitrite concentration in the brain, especially in the olfactory bulb, and reduced expression of nNOS in the brain of tau mice. These findings provided evidence of olfactory dysfunctions correlated with decreased nitric oxide production in the brain of tau mice.

  9. Below-ground plant parts emit herbivore-induced volatiles: olfactory responses of a predatory mite to tulip bulbs infested by rust mites.

    Science.gov (United States)

    Aratchige, N S; Lesna, I; Sabelis, M W

    2004-01-01

    Although odour-mediated interactions among plants, spider mites and predatory mites have been extensively studied above-ground, belowground studies are in their infancy. In this paper, we investigate whether feeding by rust mites (Aceria tulipae) cause tulip bulbs to produce odours that attract predatory mites (Neoseiulus cucumeris). Since our aim was to demonstrate such odours and not their relevance under soil conditions, the experiments were carried out using a classic Y-tube olfactometer in which the predators moved on a Y-shaped wire in open air. We found that food-deprived female predators can discriminate between odours from infested bulbs and odours from uninfested bulbs or artificially wounded bulbs. No significant difference in attractiveness to predators was found between clean bulbs and bulbs either wounded 30 min or 3 h before the experiment. These results indicate that it may not be simply the wounding of the bulbs, but rather the feeding by rust mites, which causes the bulb to release odours that attract N. cucumeris. Since bulbs are belowground plant structures, the olfactometer results demonstrate the potential for odour-mediated interactions in the soil. However, their importance in the actual soil medium remains to be demonstrated.

  10. Acetylcholine and Olfactory Perceptual Learning

    Science.gov (United States)

    Wilson, Donald A.; Fletcher, Max L.; Sullivan, Regina M.

    2004-01-01

    Olfactory perceptual learning is a relatively long-term, learned increase in perceptual acuity, and has been described in both humans and animals. Data from recent electrophysiological studies have indicated that olfactory perceptual learning may be correlated with changes in odorant receptive fields of neurons in the olfactory bulb and piriform…

  11. Effects of repeated 9 and 30-day exposure to extremely low-frequency electromagnetic fields on social recognition behavior and estrogen receptors expression in olfactory bulb of Wistar female rats.

    Science.gov (United States)

    Bernal-Mondragón, C; Arriaga-Avila, V; Martínez-Abundis, E; Barrera-Mera, B; Mercado-Gómez, O; Guevara-Guzmán, R

    2017-02-01

    We investigated the short- and long-term effects of extremely low-frequency electromagnetic fields (EMF) on social recognition behavior and expression of α- and β-estrogen receptors (ER). Rats were exposed to 60-Hz electromagnetic fields for 9 or 30 days and tested for social recognition behavior. Immunohistochemistry and western blot assays were performed to evaluate α- and β-ER expression in the olfactory bulb of intact, ovariectomized (OVX), and ovariectomized+estradiol (E2) replacement (OVX+E2). Ovariectomization showed impairment of social recognition after 9 days of EMF exposure and a complete recovery after E2 replacement and so did those after 30 days. Short EMF exposure increased expression of β-ER in intact, but not in the others. Longer exposure produced a decrease in intact but an increase in OVX and OVX+E2. Our findings suggest a significant role for β-estrogen receptors and a lack of effect for α-estrogen receptors on a social recognition task. EMF: extremely low frequency electromagnetic fields; ERs: estrogen receptors; OB: olfactory bulb; OVX: ovariectomized; OVX + E 2 : ovariectomized + estradiol replacement; IEI: interexposure interval; β-ER: beta estrogen receptor; E 2 : replacement of estradiol; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; WB: Western blot; PBS: phosphate-buffer saline; PB: phosphate-buffer.

  12. A Robust Feedforward Model of the Olfactory System.

    Directory of Open Access Journals (Sweden)

    Yilun Zhang

    2016-04-01

    Full Text Available Most natural odors have sparse molecular composition. This makes the principles of compressed sensing potentially relevant to the structure of the olfactory code. Yet, the largely feedforward organization of the olfactory system precludes reconstruction using standard compressed sensing algorithms. To resolve this problem, recent theoretical work has shown that signal reconstruction could take place as a result of a low dimensional dynamical system converging to one of its attractor states. However, the dynamical aspects of optimization slowed down odor recognition and were also found to be susceptible to noise. Here we describe a feedforward model of the olfactory system that achieves both strong compression and fast reconstruction that is also robust to noise. A key feature of the proposed model is a specific relationship between how odors are represented at the glomeruli stage, which corresponds to a compression, and the connections from glomeruli to third-order neurons (neurons in the olfactory cortex of vertebrates or Kenyon cells in the mushroom body of insects, which in the model corresponds to reconstruction. We show that should this specific relationship hold true, the reconstruction will be both fast and robust to noise, and in particular to the false activation of glomeruli. The predicted connectivity rate from glomeruli to third-order neurons can be tested experimentally.

  13. Beyond Modeling: All-Atom Olfactory Receptor Model Simulations

    Directory of Open Access Journals (Sweden)

    Peter C Lai

    2012-05-01

    Full Text Available Olfactory receptors (ORs are a type of GTP-binding protein-coupled receptor (GPCR. These receptors are responsible for mediating the sense of smell through their interaction with odor ligands. OR-odorant interactions marks the first step in the process that leads to olfaction. Computational studies on model OR structures can validate experimental functional studies as well as generate focused and novel hypotheses for further bench investigation by providing a view of these interactions at the molecular level. Here we have shown the specific advantages of simulating the dynamic environment that is associated with OR-odorant interactions. We present a rigorous methodology that ranges from the creation of a computationally-derived model of an olfactory receptor to simulating the interactions between an OR and an odorant molecule. Given the ubiquitous occurrence of GPCRs in the membranes of cells, we anticipate that our OR-developed methodology will serve as a model for the computational structural biology of all GPCRs.

  14. PKA increases in the olfactory bulb act as unconditioned stimuli and provide evidence for parallel memory systems: pairing odor with increased PKA creates intermediate- and long-term, but not short-term, memories.

    Science.gov (United States)

    Grimes, Matthew T; Harley, Carolyn W; Darby-King, Andrea; McLean, John H

    2012-02-21

    Neonatal odor-preference memory in rat pups is a well-defined associative mammalian memory model dependent on cAMP. Previous work from this laboratory demonstrates three phases of neonatal odor-preference memory: short-term (translation-independent), intermediate-term (translation-dependent), and long-term (transcription- and translation-dependent). Here, we use neonatal odor-preference learning to explore the role of olfactory bulb PKA in these three phases of mammalian memory. PKA activity increased normally in learning animals 10 min after a single training trial. Inhibition of PKA by Rp-cAMPs blocked intermediate-term and long-term memory, with no effect on short-term memory. PKA inhibition also prevented learning-associated CREB phosphorylation, a transcription factor implicated in long-term memory. When long-term memory was rescued through increased β-adrenoceptor activation, CREB phosphorylation was restored. Intermediate-term and long-term, but not short-term odor-preference memories were generated by pairing odor with direct PKA activation using intrabulbar Sp-cAMPs, which bypasses β-adrenoceptor activation. Higher levels of Sp-cAMPs enhanced memory by extending normal 24-h retention to 48-72 h. These results suggest that increased bulbar PKA is necessary and sufficient for the induction of intermediate-term and long-term odor-preference memory, and suggest that PKA activation levels also modulate memory duration. However, short-term memory appears to use molecular mechanisms other than the PKA/CREB pathway. These mechanisms, which are also recruited by β-adrenoceptor activation, must operate in parallel with PKA activation.

  15. A spiking neural network model of self-organized pattern recognition in the early mammalian olfactory system

    Science.gov (United States)

    Kaplan, Bernhard A.; Lansner, Anders

    2014-01-01

    Olfactory sensory information passes through several processing stages before an odor percept emerges. The question how the olfactory system learns to create odor representations linking those different levels and how it learns to connect and discriminate between them is largely unresolved. We present a large-scale network model with single and multi-compartmental Hodgkin–Huxley type model neurons representing olfactory receptor neurons (ORNs) in the epithelium, periglomerular cells, mitral/tufted cells and granule cells in the olfactory bulb (OB), and three types of cortical cells in the piriform cortex (PC). Odor patterns are calculated based on affinities between ORNs and odor stimuli derived from physico-chemical descriptors of behaviorally relevant real-world odorants. The properties of ORNs were tuned to show saturated response curves with increasing concentration as seen in experiments. On the level of the OB we explored the possibility of using a fuzzy concentration interval code, which was implemented through dendro-dendritic inhibition leading to winner-take-all like dynamics between mitral/tufted cells belonging to the same glomerulus. The connectivity from mitral/tufted cells to PC neurons was self-organized from a mutual information measure and by using a competitive Hebbian–Bayesian learning algorithm based on the response patterns of mitral/tufted cells to different odors yielding a distributed feed-forward projection to the PC. The PC was implemented as a modular attractor network with a recurrent connectivity that was likewise organized through Hebbian–Bayesian learning. We demonstrate the functionality of the model in a one-sniff-learning and recognition task on a set of 50 odorants. Furthermore, we study its robustness against noise on the receptor level and its ability to perform concentration invariant odor recognition. Moreover, we investigate the pattern completion capabilities of the system and rivalry dynamics for odor mixtures. PMID

  16. Below-ground plant parts emit herbivore-induced volatiles: olfactory responses of a predatory mite to tulip bulbs infested by rust mites

    NARCIS (Netherlands)

    Aratchige, N.S.; Lesna, I.; Sabelis, M.W.

    2004-01-01

    Although odour-mediated interactions among plants, spider mites and predatory mites have been extensively studied above-ground, belowground studies are in their infancy. In this paper, we investigate whether feeding by rust mites (Aceria tulipae) cause tulip bulbs to produce odours that attract

  17. Sniffing and Oxytocin: Effects on Olfactory Memories.

    Science.gov (United States)

    Stoop, Ron

    2016-05-04

    In this issue of Neuron, Oettl et al. (2016) show how oxytocin can boost processing of olfactory information in female rats by a top-downregulation from the anterior olfactory nucleus onto the main olfactory bulb. As a result, interactions with juvenile conspecifics receive more attention and are longer memorized. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Equipment for fully homologous bulb turbine model testing in Laval University

    International Nuclear Information System (INIS)

    Fraser R; Vallée D; Jean Y; Deschênes C

    2014-01-01

    Within the context of liberalisation of the energy market, hydroelectricity remains a first class source of clean and renewable energy. Combining the growing demand of energy, its increasing value and the appreciation associated to the sustainable development, low head sites formerly considered as non-profitable are now exploitable. Bulb turbines likely to equip such sites are traditionally developed on model using right angle transmission leading to piers enlargement for power take off shaft passage, thus restricting possibilities to have fully homologous hydraulic passages. Aiming to sustain good quality development on fully homologous scale model of bulb turbines, the Hydraulic Machines Laboratory (LAMH) of Laval University has developed a brake with an enhanced power to weight ratio. This powerful brake is small enough to be located in the bulb shell while dissipating power without mandatory test head reduction. This paper first presents the basic technology of this brake and its application. Then both its main performance capabilities and dimensional characteristics will be detailed. The instrumentation used to perform accurate measurements will be finally presented

  19. Immunocytochemistry of the olfactory marker protein.

    Science.gov (United States)

    Monti-Graziadei, G A; Margolis, F L; Harding, J W; Graziadei, P P

    1977-12-01

    The olfactory marker protein has been localized, by means of immunohistochemical techniques in the primary olfactory neurons of mice. The olfactory marker protein is not present in the staminal cells of the olfactory neuroepithelium, and the protein may be regarded as indicative of the functional stage of the neurons. Our data indicate that the olfactory marker protein is present in the synaptic terminals of the olfactory neurons at the level of the olfactory bulb glomeruli. The postsynaptic profiles of both mitral and periglomerular cells are negative.

  20. The temporal expression pattern of alpha-synuclein modulates olfactory neurogenesis in transgenic mice.

    Directory of Open Access Journals (Sweden)

    Sebastian R Schreglmann

    Full Text Available Adult neurogenesis mirrors the brain´s endogenous capacity to generate new neurons throughout life. In the subventricular zone/ olfactory bulb system adult neurogenesis is linked to physiological olfactory function and has been shown to be impaired in murine models of neuronal alpha-Synuclein overexpression. We analyzed the degree and temporo-spatial dynamics of adult olfactory bulb neurogenesis in transgenic mice expressing human wild-type alpha-Synuclein (WTS under the murine Thy1 (mThy1 promoter, a model known to have a particularly high tg expression associated with impaired olfaction.Survival of newly generated neurons (NeuN-positive in the olfactory bulb was unchanged in mThy1 transgenic animals. Due to decreased dopaminergic differentiation a reduction in new dopaminergic neurons within the olfactory bulb glomerular layer was present. This is in contrast to our previously published data on transgenic animals that express WTS under the control of the human platelet-derived growth factor β (PDGF promoter, that display a widespread decrease in survival of newly generated neurons in regions of adult neurogenesis, resulting in a much more pronounced neurogenesis deficit. Temporal and quantitative expression analysis using immunofluorescence co-localization analysis and Western blots revealed that in comparison to PDGF transgenic animals, in mThy1 transgenic animals WTS is expressed from later stages of neuronal maturation only but at significantly higher levels both in the olfactory bulb and cortex.The dissociation between higher absolute expression levels of alpha-Synuclein but less severe impact on adult olfactory neurogenesis in mThy1 transgenic mice highlights the importance of temporal expression characteristics of alpha-Synuclein on the maturation of newborn neurons.

  1. Towards structural models of molecular recognition in olfactory receptors.

    Science.gov (United States)

    Afshar, M; Hubbard, R E; Demaille, J

    1998-02-01

    The G protein coupled receptors (GPCR) are an important class of proteins that act as signal transducers through the cytoplasmic membrane. Understanding the structure and activation mechanism of these proteins is crucial for understanding many different aspects of cellular signalling. The olfactory receptors correspond to the largest family of GPCRs. Very little is known about how the structures of the receptors govern the specificity of interaction which enables identification of particular odorant molecules. In this paper, we review recent developments in two areas of molecular modelling: methods for modelling the configuration of trans-membrane helices and methods for automatic docking of ligands into receptor structures. We then show how a subset of these methods can be combined to construct a model of a rat odorant receptor interacting with lyral for which experimental data are available. This modelling can help us make progress towards elucidating the specificity of interactions between receptors and odorant molecules.

  2. Matter-neutrino resonance in a multiangle neutrino bulb model

    Science.gov (United States)

    Vlasenko, Alexey; McLaughlin, G. C.

    2018-04-01

    Simulations of neutrino flavor evolution in compact merger environments have shown that neutrino flavor, and hence nucleosynthesis, can be strongly affected by the presence of matter-neutrino resonances (MNRs), where there is a cancelation between the matter and the neutrino potential. Simulations performed thus far follow flavor evolution along a single neutrino trajectory, but self-consistency requires all trajectories to be treated simultaneously, and it has not been known whether MNR phenomena would still occur in multiangle models. In this paper, we present the first fully multi-angle calculations of MNR. We find that familiar MNR phenomena, where neutrinos transform to a greater extent than anti-neutrinos and a feedback mechanism maintains the cancellation between the matter and neutrino potential, still occurs for a subset of angular bins, although the flavor transformation is not as efficient as in the single-angle case. In addition, we find other types of flavor transformation that are not seen in single-angle simulations. These flavor transformation phenomena appear to be robust and are present for a wide range of model parameters, as long as an MNR is present. Although computational constraints currently limit us to models with spherical symmetry, our results suggest that the presence of an MNR generally leads to large-scale neutrino flavor evolution in multiangle systems.

  3. Olfactory impairment in the rotenone model of Parkinson's disease is associated with bulbar dopaminergic D2 activity after REM sleep deprivation

    Directory of Open Access Journals (Sweden)

    Laís Soares Rodrigues

    2014-12-01

    Full Text Available Olfactory and rapid eye movement (REM sleep deficits are commonly found in untreated subjects with a recent diagnosis of Parkinson's disease (PD. Besides different studies reported declines in olfactory performances during a short period of sleep deprivation. Mechanisms underlying these clinical manifestations are poorly understood although the impairment in the dopamine (DA neurotransmission in the olfactory bulb and in the nigrostriatal pathway may have important roles in olfactory as well as in REM sleep disturbances. Therefore, we have led to the hypothesis that a modulation of the dopaminergic D2 receptors in the olfactory bulb could provide a more comprehensive understanding of the olfactory deficits in PD and after a short period of REM sleep deprivation (REMSD. We decided to investigate the olfactory, neurochemical and histological alterations generated by the administration of piribedil (a selective D2 agonist or raclopride (a selective D2 antagonist, within the glomerular layer of the olfactory bulb, in rats submitted to intranigral rotenone and REMSD. Our findings provided a remarkable evidence of the occurrence of a negative correlation (r = - 0.52, P = 0.04 between the number of periglomerular TH-ir neurons and the bulbar levels of DA in the rotenone, but not sham groups. A significant positive correlation (r = 0.34, P = 0.03 was observed between nigral DA and olfactory discrimination index (DI, for the sham groups, indicating that increased DA levels in the substantia nigra pars compacta (SNpc are associated to enhanced olfactory discrimination performance. Also, increased levels in bulbar and striatal DA induced by piribedil in the rotenone control and rotenone REMSD groups were consistent with reduced amounts of DI. The present evidence reinforce that DA produced by periglomerular neurons, and particularly the bulbar dopaminergic D2 receptors, are essential participants in the olfactory discrimination processes, as well as SNpc

  4. Olfactory impairment is related to REM sleep deprivation in rotenone model of Parkinson's disease

    Directory of Open Access Journals (Sweden)

    Mariana F. Aurich

    Full Text Available Introduction: Olfactory dysfunction affects about 85-90% of Parkinson's disease (PD patients with severe deterioration in the ability of discriminate several types of odors. In addition, studies reported declines in olfactory performances during a short period of sleep deprivation. Besides, PD is also known to strongly affect the occurrence and maintenance of rapid eye movement (REM sleep. Methods: Therefore, we investigated the mechanisms involved on discrimination of a social odor (dependent on the vomeronasal system and a non-social odor (related to the main olfactory pathway in the rotenone model of PD. Also, a concomitant impairment in REM sleep was inflicted with the introduction of two periods (24 or 48 h of REM sleep deprivation (REMSD. Rotenone promoted a remarkable olfactory impairment in both social and non-social odors, with a notable modulation induced by 24 h of REMSD for the non-social odor. Results: Our findings demonstrated the occurrence of a strong association between the density of nigral TH-ir neurons and the olfactory discrimination capacity for both odorant stimuli. Specifically, the rotenone-induced decrease of these neurons tends to elicit reductions in the olfactory discrimination ability. Conclusions: These results are consistent with the participation of the nigrostriatal dopaminergic system mainly in the olfactory discrimination of a non-social odor, probably through the main olfactory pathway. Such involvement may have produce relevant impact in the preclinical abnormalities found in PD patients.

  5. Olfactory discrimination and memory deficits in the Flinders Sensitive Line rodent model of depression.

    Science.gov (United States)

    Cook, A; Pfeiffer, L-M; Thiele, S; Coenen, V A; Döbrössy, M D

    2017-10-01

    Major Depressive Disorder (MDD) is a heterogeneous psychiatric disorder with broad symptomatic manifestations. The current study examined, for the first time, olfactory memory and discrimination in the Flinders Sensitive Line (FSL) rodent model of depression. Male FSL rats and controls were trained on an Olfactory Discrimination (OD) and a Social Interaction (SI) test. On the OD test, the FSL and controls performed similarly at the shortest inter-trial interval (5min), however, with extended delay of 30min, the FSLs had a recall and odour discrimination deficit. At the longest delay (60min) both groups performed poorly. The FSL rats i.) had a deficit in olfactory discrimination suggesting impairment in olfactory memory and recall; ii.) were less likely to socialize with unfamiliar rats. The data suggests that FSL animals have an impaired olfactory information processing capacity. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Heat balance model for a human body in the form of wet bulb globe temperature indices.

    Science.gov (United States)

    Sakoi, Tomonori; Mochida, Tohru; Kurazumi, Yoshihito; Kuwabara, Kohei; Horiba, Yosuke; Sawada, Shin-Ichi

    2018-01-01

    The purpose of this study is to expand the empirically derived wet bulb globe temperature (WBGT) index to a rational thermal index based on the heat balance for a human body. We derive the heat balance model in the same form as the WBGT for a human engaged in moderate intensity work with a metabolic heat production of 174W/m 2 while wearing typical vapor-permeable clothing under shady and sunny conditions. Two important relationships are revealed based on this derivation: (1) the natural wet bulb and black globe temperature coefficients in the WBGT coincide with the heat balance equation for a human body with a fixed skin wettedness of approximately 0.45 at a fixed skin temperature; and (2) the WBGT can be interpreted as the environmental potential to increase skin temperature rather than the heat storage rate of a human body. We propose an adjustment factor calculation method that supports the application of WBGT for humans dressed in various clothing types and working under various air velocity conditions. Concurrently, we note difficulties in adjusting the WBGT by using a single factor for humans wearing vapor-impermeable protective clothing. The WBGT for shady conditions does not need adjustment depending on the positive radiant field (i.e., when a radiant heat source exists), whereas that for the sunny condition requires adjustments because it underestimates heat stress, which may result in insufficient human protection measures. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Galantamine improves olfactory learning in the Ts65Dn mouse model of Down syndrome.

    Science.gov (United States)

    de Souza, Fabio M Simoes; Busquet, Nicolas; Blatner, Megan; Maclean, Kenneth N; Restrepo, Diego

    2011-01-01

    Down syndrome (DS) is the most common form of congenital intellectual disability. Although DS involves multiple disturbances in various tissues, there is little doubt that in terms of quality of life cognitive impairment is the most serious facet and there is no effective treatment for this aspect of the syndrome. The Ts65Dn mouse model of DS recapitulates multiple aspects of DS including cognitive impairment. Here the Ts65Dn mouse model of DS was evaluated in an associative learning paradigm based on olfactory cues. In contrast to disomic controls, trisomic mice exhibited significant deficits in olfactory learning. Treatment of trisomic mice with the acetylcholinesterase inhibitor galantamine resulted in a significant improvement in olfactory learning. Collectively, our study indicates that olfactory learning can be a sensitive tool for evaluating deficits in associative learning in mouse models of DS and that galantamine has therapeutic potential for improving cognitive abilities.

  8. Imaging the olfactory tract (Cranial Nerve no.1)

    International Nuclear Information System (INIS)

    Duprez, Thierry P.; Rombaux, Philippe

    2010-01-01

    This review paper browses pros and cons of the different radiological modalities for imaging the olfactory tract and highlights the potential benefits and limitation of more recent advances in MR and CT technology. A systematic pictorial overview of pathological conditions affecting olfactory sense is given. Techniques for collecting quantitative data on olfactory bulb volume and on olfactory sulcus depth are described. At last, insights into functional imaging of olfactory sense are shown.

  9. A computational model of conditioning inspired by Drosophila olfactory system.

    Science.gov (United States)

    Faghihi, Faramarz; Moustafa, Ahmed A; Heinrich, Ralf; Wörgötter, Florentin

    2017-03-01

    Recent studies have demonstrated that Drosophila melanogaster (briefly Drosophila) can successfully perform higher cognitive processes including second order olfactory conditioning. Understanding the neural mechanism of this behavior can help neuroscientists to unravel the principles of information processing in complex neural systems (e.g. the human brain) and to create efficient and robust robotic systems. In this work, we have developed a biologically-inspired spiking neural network which is able to execute both first and second order conditioning. Experimental studies demonstrated that volume signaling (e.g. by the gaseous transmitter nitric oxide) contributes to memory formation in vertebrates and invertebrates including insects. Based on the existing knowledge of odor encoding in Drosophila, the role of retrograde signaling in memory function, and the integration of synaptic and non-synaptic neural signaling, a neural system is implemented as Simulated fly. Simulated fly navigates in a two-dimensional environment in which it receives odors and electric shocks as sensory stimuli. The model suggests some experimental research on retrograde signaling to investigate neural mechanisms of conditioning in insects and other animals. Moreover, it illustrates a simple strategy to implement higher cognitive capabilities in machines including robots. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Evaporator bulb

    International Nuclear Information System (INIS)

    Stoll, W.

    1977-01-01

    In order to prevent the hazard of a possible excursion in an evaporator bulb for radioactive liquids there is provided in the bottom of the vessel a recess filled with a neutron-absorbing and moderating material. The bottom drain pipe is coming out sideways and connected with a heated pipe feeding above into the vessel tangentially. (TK) [de

  11. The comparative analysis of model and prototype test results of Bulb turbine

    International Nuclear Information System (INIS)

    Benisek, M; Bozic, I; Ignjatovic, B

    2010-01-01

    This paper presents the problem of the hydropower plant oblique water inflow and its influence on the turbines operation. Oblique water inflow on the low head hydropower plant with bulb turbines influences turbine characteristics. The characteristics change occurs due to swirl incidence in the turbine inlet which spreads to the guide vanes inlet. Downstream, the flow conditions change is caused in the turbine runner in relation to the flow conditions without swirl inflow. Special attention is paid to the phenomenon of swirl flow incidence in the turbine conduit. With the aim of presenting and analyzing the oblique water inflow consequences on the hydropower plant operation, the existing turbine model tests results, performed in the laboratories, and the in situ prototype testing results have been used.

  12. Assessment of Olfactory Memory in Olfactory Dysfunction.

    Science.gov (United States)

    Kollndorfer, Kathrin; Reichert, Johanna; Braunsteiner, Josephine; Schöpf, Veronika

    2017-01-01

    To assess all clinically relevant components of olfactory perception, examinations for olfactory sensitivity, discrimination, and identification are performed. Besides the standard perceptual test battery, episodic olfactory memory might offer additional information about olfactory abilities relative to these standard clinical tests. As both olfactory deficits and memory deficits are early symptoms in neurodegenerative disorders, olfactory memory may be of particular interest. However, to date little is known about episodic olfactory memory performance in patients with decreased olfactory function. This study includes the investigation of olfactory memory performance in 14 hyposmic patients (8 female, mean age 52.6 years) completing two episodic odor memory tests (Sniffin' Test of Odor Memory and Odor Memory Test). To control for a general impairment in memory function, a verbal and a figural memory test were carried out. A regression model with multiple predictors was calculated for both odor memory tests separately. Odor identification was identified as the only significant predictor for both odor memory tasks. From our results, we conclude that currently available olfactory memory tests are highly influenced by odor identification abilities, implying the need for the development and validation of additional tests in this field which could serve as additional olfactory perception variables for clinical assessment.

  13. Aversive cues fail to activate fos expression in the asymmetric olfactory-habenula pathway of zebrafish

    Directory of Open Access Journals (Sweden)

    Tagide N. Decarvalho

    2013-05-01

    Full Text Available The dorsal habenular nuclei of the zebrafish epithalamus have become a valuable model for studying the development of left-right (L-R asymmetry and its function in the vertebrate brain. The bilaterally paired dorsal habenulae exhibit striking differences in size, neuroanatomical organization and molecular properties. They also display differences in their efferent connections with the interpeduncular nucleus (IPN and in their afferent input, with a subset of mitral cells distributed on both sides of the olfactory bulb innervating only the right habenula. Previous studies have implicated the dorsal habenulae in modulating fear/anxiety responses in juvenile and adult zebrafish. It has been suggested that the asymmetric olfactory-habenula pathway (OB-Ha, revealed by selective labeling from an lhx2a:YFP transgene, mediates fear behaviors elicited by alarm pheromone. Here we show that expression of the fam84b gene demarcates a unique region of the right habenula that is the site of innervation by lhx2a:YFP-labeled olfactory axons. Upon ablation of the parapineal, which normally promotes left habenular identity; the fam84b domain is present in both dorsal habenulae and lhx2a:YFP-labeled olfactory bulb neurons form synapses on the left and the right side. To explore the relevance of the asymmetric olfactory projection and how it might influence habenular function, we tested activation of this pathway using odorants known to evoke behaviors. We find that alarm substance or other aversive odors, and attractive cues, activate fos expression in subsets of cells in the olfactory bulb but not in the lhx2a:YFP expressing population. Moreover, neither alarm pheromone nor chondroitin sulfate elicited fos activation in the dorsal habenulae. The results indicate that L-R asymmetry of the epithalamus sets the directionality of olfactory innervation, however, the lhx2a:YFP olfactory-habenula pathway does not appear to mediate fear responses to aversive odorants.

  14. Olfactory deficits in Niemann-Pick type C1 (NPC1 disease.

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    Marina Hovakimyan

    Full Text Available BACKGROUND: Niemann-Pick type C disease (NPC is a rare autosomal recessive lipid storage disease characterized by progressive neurodegeneration. As only a few studies have been conducted on the impact of NPC on sensory systems, we used a mutant mouse model (NPC1(-/- to examine the effects of this disorder to morphologically distinct regions of the olfactory system, namely the olfactory epithelium (OE and olfactory bulb (OB. METHODOLOGY/PRINCIPAL FINDINGS: For structural and functional analysis immunohistochemistry, electron microscopy, western blotting, and electrophysiology have been applied. For histochemistry and western blotting, we used antibodies against a series of neuronal and glia marker proteins, as well as macrophage markers. NPC1(-/- animals present myelin-like lysosomal deposits in virtually all types of cells of the peripheral and central olfactory system. Especially supporting cells of the OE and central glia cells are affected, resulting in pronounced astrocytosis and microgliosis in the OB and other olfactory cortices. Up-regulation of Galectin-3, Cathepsin D and GFAP in the cortical layers of the OB underlines the critical role and location of the OB as a possible entrance gate for noxious substances. Unmyelinated olfactory afferents of the lamina propria seem less affected than ensheathing cells. Supporting the structural findings, electro-olfactometry of the olfactory mucosa suggests that NPC1(-/- animals exhibit olfactory and trigeminal deficits. CONCLUSIONS/SIGNIFICANCE: Our data demonstrate a pronounced neurodegeneration and glia activation in the olfactory system of NPC1(-/-, which is accompanied by sensory deficits.

  15. Olfactory-Induced Synesthesias: A Review and Model

    Science.gov (United States)

    Stevenson, Richard J.; Tomiczek, Caroline

    2007-01-01

    Recent reviews of synesthesia concentrate upon rare neurodevelopmental examples and exclude common olfactory-induced experiences with which they may profitably be compared. Like the neurodevelopmental synesthesias, odor-induced experiences involve different sensory modalities; are reliable, asymmetric (concurrents cannot induce), and automatic;…

  16. Neural Correlates of Olfactory Learning: Critical Role of Centrifugal Neuromodulation

    Science.gov (United States)

    Fletcher, Max L.; Chen, Wei R.

    2010-01-01

    The mammalian olfactory system is well established for its remarkable capability of undergoing experience-dependent plasticity. Although this process involves changes at multiple stages throughout the central olfactory pathway, even the early stages of processing, such as the olfactory bulb and piriform cortex, can display a high degree of…

  17. Assessment of olfactory nerve by SPECT-MRI image with nasal thallium-201 administration in patients with olfactory impairments in comparison to healthy volunteers.

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    Hideaki Shiga

    Full Text Available PURPOSE: The aim of this study was to assess whether migration of thallium-201 ((201Tl to the olfactory bulb were reduced in patients with olfactory impairments in comparison to healthy volunteers after nasal administration of (201Tl. PROCEDURES: 10 healthy volunteers and 21 patients enrolled in the study (19 males and 12 females; 26-71 years old. The causes of olfactory dysfunction in the patients were head trauma (n = 7, upper respiratory tract infection (n = 7, and chronic rhinosinusitis (n = 7. (201TlCl was administered unilaterally to the olfactory cleft, and SPECT-CT was conducted 24 h later. Separate MRI images were merged with the SPECT images. (201Tl olfactory migration was also correlated with the volume of the olfactory bulb determined from MRI images, as well as with odor recognition thresholds measured by using T&T olfactometry. RESULTS: Nasal (201Tl migration to the olfactory bulb was significantly lower in the olfactory-impaired patients than in healthy volunteers. The migration of (201Tl to the olfactory bulb was significantly correlated with odor recognition thresholds obtained with T&T olfactometry and correlated with the volume of the olfactory bulb determined from MRI images when all subjects were included. CONCLUSIONS: Assessment of the (201Tl migration to the olfactory bulb was the new method for the evaluation of the olfactory nerve connectivity in patients with impaired olfaction.

  18. QUASARS ARE NOT LIGHT BULBS: TESTING MODELS OF QUASAR LIFETIMES WITH THE OBSERVED EDDINGTON RATIO DISTRIBUTION

    International Nuclear Information System (INIS)

    Hopkins, Philip F.; Hernquist, Lars

    2009-01-01

    We use the observed distribution of Eddington ratios as a function of supermassive black hole (BH) mass to constrain models of quasar/active galactic nucleus (AGN) lifetimes and light curves. Given the observed (well constrained) AGN luminosity function, a particular model for AGN light curves L(t) or, equivalently, the distribution of AGN lifetimes (time above a given luminosity t(>L)) translates directly and uniquely (without further assumptions) to a predicted distribution of Eddington ratios at each BH mass. Models for self-regulated BH growth, in which feedback produces a self-regulating 'decay' or 'blowout' phase after the AGN reaches some peak luminosity/BH mass and begins to expel gas and shut down accretion, make specific predictions for the light curves/lifetimes, distinct from, e.g., the expected distribution if AGN simply shut down by gas starvation (without feedback) and very different from the prediction of simple phenomenological 'light bulb' scenarios. We show that the present observations of the Eddington ratio distribution, spanning nearly 5 orders of magnitude in Eddington ratio, 3 orders of magnitude in BH mass, and redshifts z = 0-1, agree well with the predictions of self-regulated models, and rule out phenomenological 'light bulb' or pure exponential models, as well as gas starvation models, at high significance (∼5σ). We also compare with observations of the distribution of Eddington ratios at a given AGN luminosity, and find similar good agreement (but show that these observations are much less constraining). We fit the functional form of the quasar lifetime distribution and provide these fits for use, and show how the Eddington ratio distributions place precise, tight limits on the AGN lifetimes at various luminosities, in agreement with model predictions. We compare with independent estimates of episodic lifetimes and use this to constrain the shape of the typical AGN light curve, and provide simple analytic fits to these for use in

  19. Fus1 KO mouse as a model of oxidative stress-mediated sporadic Alzheimer’s disease: circadian disruption and long-term spatial and olfactory memory impairments.

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    Guillermo Coronas-Samano

    2016-11-01

    Full Text Available Insufficient advances in the development of effective therapeutic treatments of sporadic Alzheimer's Disease (sAD to date are largely due to the lack of sAD-relevant animal models. While the vast majority of models do recapitulate AD's hallmarks of plaques and tangles by virtue of tau and/or beta amyloid overexpression, these models do not reflect the fact that in sAD (unlike familial AD these genes are not risk factors per se and that other mechanisms like oxidative stress, metabolic dysregulation and inflammation play key roles in AD etiology. Here we characterize and propose the Fus1 KO mice that lack a mitochondrial protein Fus1/Tusc2 as a new sAD model. To establish sAD relevance, we assessed sAD related deficits in Fus1 KO and WT adult mice of 4-5 months old, the equivalent human age when the earliest cognitive and olfactory sAD symptoms arise. Fus1 KO mice showed oxidative stress (increased levels of ROS, decreased levels of PRDX1, disruption of metabolic homeostasis (decreased levels of ACC2, increased phosphorylation of AMPK, autophagy (decreased levels of LC3-II, PKC (decreased levels of RACK1 and calcium signaling (decreased levels of Calb2 in the olfactory bulb and/or hippocampus. Mice were behaviorally tested using objective and accurate video tracking (Noldus, in which Fus1 KO mice showed clear deficits in olfactory memory (decreased habituation/cross-habituation in the short and long term, olfactory guided navigation memory (inability to reduce their latency to find the hidden cookie, spatial memory (learning impairments on finding the platform in the Morris water maze and showed more sleep time during the diurnal cycle. Fus1 KO mice did not show clear deficits in olfactory perception (cross-habituation, association memory (passive avoidance or in species-typical behavior (nest building and no increased anxiety (open field, light-dark box or depression/anhedonia (sucrose preference at this relatively young age. These

  20. Fus1 KO Mouse As a Model of Oxidative Stress-Mediated Sporadic Alzheimer's Disease: Circadian Disruption and Long-Term Spatial and Olfactory Memory Impairments.

    Science.gov (United States)

    Coronas-Samano, Guillermo; Baker, Keeley L; Tan, Winston J T; Ivanova, Alla V; Verhagen, Justus V

    2016-01-01

    Insufficient advances in the development of effective therapeutic treatments of sporadic Alzheimer's Disease (sAD) to date are largely due to the lack of sAD-relevant animal models. While the vast majority of models do recapitulate AD's hallmarks of plaques and tangles by virtue of tau and/or beta amyloid overexpression, these models do not reflect the fact that in sAD (unlike familial AD) these genes are not risk factors per se and that other mechanisms like oxidative stress, metabolic dysregulation and inflammation play key roles in AD etiology. Here we characterize and propose the Fus1 KO mice that lack a mitochondrial protein Fus1/Tusc2 as a new sAD model. To establish sAD relevance, we assessed sAD related deficits in Fus1 KO and WT adult mice of 4-5 months old, the equivalent human age when the earliest cognitive and olfactory sAD symptoms arise. Fus1 KO mice showed oxidative stress (increased levels of ROS, decreased levels of PRDX1), disruption of metabolic homeostasis (decreased levels of ACC2, increased phosphorylation of AMPK), autophagy (decreased levels of LC3-II), PKC (decreased levels of RACK1) and calcium signaling (decreased levels of Calb2) in the olfactory bulb and/or hippocampus. Mice were behaviorally tested using objective and accurate video tracking (Noldus), in which Fus1 KO mice showed clear deficits in olfactory memory (decreased habituation/cross-habituation in the short and long term), olfactory guided navigation memory (inability to reduce their latency to find the hidden cookie), spatial memory (learning impairments on finding the platform in the Morris water maze) and showed more sleep time during the diurnal cycle. Fus1 KO mice did not show clear deficits in olfactory perception (cross-habituation), association memory (passive avoidance) or in species-typical behavior (nest building) and no increased anxiety (open field, light-dark box) or depression/anhedonia (sucrose preference) at this relatively young age. These neurobehavioral

  1. Olfactory Fear Conditioning Induces Field Potential Potentiation in Rat Olfactory Cortex and Amygdala

    Science.gov (United States)

    Messaoudi, Belkacem; Granjon, Lionel; Mouly, Anne-Marie; Sevelinges, Yannick; Gervais, Remi

    2004-01-01

    The widely used Pavlovian fear-conditioning paradigms used for studying the neurobiology of learning and memory have mainly used auditory cues as conditioned stimuli (CS). The present work assessed the neural network involved in olfactory fear conditioning, using olfactory bulb stimulation-induced field potential signal (EFP) as a marker of…

  2. Reorganization of neuronal circuits of the central olfactory system during postprandial sleep

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    Masahiro eYamaguchi

    2013-08-01

    Full Text Available Plastic changes in neuronal circuits often occur in association with specific behavioral states. In this review, we focus on an emerging view that neuronal circuits in the olfactory system are reorganized along the wake-sleep cycle. Olfaction is crucial to sustaining the animals’ life, and odor-guided behaviors have to be newly acquired or updated to successfully cope with a changing odor world. It is therefore likely that neuronal circuits in the olfactory system are highly plastic and undergo repeated reorganization in daily life. A remarkably plastic feature of the olfactory system is that newly generated neurons are continually integrated into neuronal circuits of the olfactory bulb (OB throughout life. New neurons in the OB undergo an extensive selection process, during which many are eliminated by apoptosis for the fine tuning of neuronal circuits. The life and death decision of new neurons occurs extensively during a short time window of sleep after food consumption (postprandial sleep, a typical daily olfactory behavior. We review recent studies that explain how olfactory information is transferred between the OB and the olfactory cortex (OC along the course of the wake-sleep cycle. Olfactory sensory input is effectively transferred from the OB to the OC during waking, while synchronized top-down inputs from the OC to the OB are promoted during the slow-wave sleep. We discuss possible neuronal circuit mechanisms for the selection of new neurons in the OB, which involves the encoding of olfactory sensory inputs and memory trace formation during waking and internally generated activities in the OC and OB during subsequent sleep. The plastic changes in the OB and OC are well coordinated along the course of olfactory behavior during wakefulness and postbehavioral rest and sleep. We therefore propose that the olfactory system provides an excellent model in which to understand behavioral state-dependent plastic mechanisms of the neuronal

  3. Suppression of Neuroinflammatory and Apoptotic Signaling Cascade by Curcumin Alone and in Combination with Piperine in Rat Model of Olfactory Bulbectomy Induced Depression

    Science.gov (United States)

    Rinwa, Puneet; Kumar, Anil; Garg, Sukant

    2013-01-01

    Objectives Bilateral destruction of the olfactory bulbs is known to cause behavioral changes analogous to symptoms of depression. Curcumin, a traditional Indian spice is currently being investigated in different psychiatric problems including depression. Dietary phytochemicals are currently used as an adjuvant therapy to accelerate their therapeutic efficacy. Therefore, the present study is an attempt to elucidate the neuroprotective mechanism of curcumin and its co-administration with piperine against olfactory bulbectomy induced depression in rats. Methods Rats undergone olfactory bulbs ablations were analyzed after post-surgical rehabilitation period of 2 weeks. Animals were then treated with different doses of curcumin (100, 200 and 400 mg/kg; p.o.), piperine (20 mg/kg; p.o.) and their combination daily for another 2 weeks. Imipramine (10 mg/kg; i.p.) served as a standard control. Various behavioral tests like forced swim test (FST), open field behaviour and sucrose preference test (SPT) were performed, followed by estimation of biochemical, mitochondrial, molecular and histopathological parameters in rat brain. Results Ablation of olfactory bulbs caused depression-like symptoms as evidenced by increased immobility time in FST, hyperactivity in open field arena, and anhedonic like response in SPT along with alterations in mitochondrial enzyme complexes, increased serum corticosterone levels and oxidative damage. These deficits were integrated with increased inflammatory cytokines (TNF-α) and apoptotic factor (caspase-3) levels along with a marked reduction in neurogenesis factor (BDNF) in the brain of olfactory bulbectomized (OBX) rats. Curcumin treatment significantly and dose-dependently restored all these behavioral, biochemical, mitochondrial, molecular and histopathological alterations associated with OBX induced depression. Further, co-administration of piperine with curcumin significantly potentiated their neuroprotective effects as compared to their

  4. Suppression of neuroinflammatory and apoptotic signaling cascade by curcumin alone and in combination with piperine in rat model of olfactory bulbectomy induced depression.

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    Puneet Rinwa

    Full Text Available OBJECTIVES: Bilateral destruction of the olfactory bulbs is known to cause behavioral changes analogous to symptoms of depression. Curcumin, a traditional Indian spice is currently being investigated in different psychiatric problems including depression. Dietary phytochemicals are currently used as an adjuvant therapy to accelerate their therapeutic efficacy. Therefore, the present study is an attempt to elucidate the neuroprotective mechanism of curcumin and its co-administration with piperine against olfactory bulbectomy induced depression in rats. METHODS: Rats undergone olfactory bulbs ablations were analyzed after post-surgical rehabilitation period of 2 weeks. Animals were then treated with different doses of curcumin (100, 200 and 400 mg/kg; p.o., piperine (20 mg/kg; p.o. and their combination daily for another 2 weeks. Imipramine (10 mg/kg; i.p. served as a standard control. Various behavioral tests like forced swim test (FST, open field behaviour and sucrose preference test (SPT were performed, followed by estimation of biochemical, mitochondrial, molecular and histopathological parameters in rat brain. RESULTS: Ablation of olfactory bulbs caused depression-like symptoms as evidenced by increased immobility time in FST, hyperactivity in open field arena, and anhedonic like response in SPT along with alterations in mitochondrial enzyme complexes, increased serum corticosterone levels and oxidative damage. These deficits were integrated with increased inflammatory cytokines (TNF-α and apoptotic factor (caspase-3 levels along with a marked reduction in neurogenesis factor (BDNF in the brain of olfactory bulbectomized (OBX rats. Curcumin treatment significantly and dose-dependently restored all these behavioral, biochemical, mitochondrial, molecular and histopathological alterations associated with OBX induced depression. Further, co-administration of piperine with curcumin significantly potentiated their neuroprotective effects as

  5. CNPase Expression in Olfactory Ensheathing Cells

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    Christine Radtke

    2011-01-01

    Full Text Available A large body of work supports the proposal that transplantation of olfactory ensheathing cells (OECs into nerve or spinal cord injuries can promote axonal regeneration and remyelination. Yet, some investigators have questioned whether the transplanted OECs associate with axons and form peripheral myelin, or if they recruit endogenous Schwann cells that form myelin. Olfactory bulbs from transgenic mice expressing the enhanced green fluorescent protein (eGFP under the control of the 2-3-cyclic nucleotide 3-phosphodiesterase (CNPase promoter were studied. CNPase is expressed in myelin-forming cells throughout their lineage. We examined CNPase expression in both in situ in the olfactory bulb and in vitro to determine if OECs express CNPase commensurate with their myelination potential. eGFP was observed in the outer nerve layer of the olfactory bulb. Dissociated OECs maintained in culture had both intense eGFP expression and CNPase immunostaining. Transplantation of OECs into transected peripheral nerve longitudinally associated with the regenerated axons. These data indicate that OECs in the outer nerve layer of the olfactory bulb of CNPase transgenic mice express CNPase. Thus, while OECs do not normally form myelin on olfactory nerve axons, their expression of CNPase is commensurate with their potential to form myelin when transplanted into injured peripheral nerve.

  6. From chemical neuroanatomy to an understanding of the olfactory system

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    L. Oboti

    2011-10-01

    Full Text Available The olfactory system is the appropriate model for studying several aspects of neuronal physiology spanning from the developmental stage to neural network remodelling in the adult brain. Both the morphological and physiological understanding of this system were strongly supported by classical histochemistry. It is emblematic the case of the Olfactory Marker Protein (OMP staining, the first, powerful marker for fully differentiated olfactory receptor neurons and a key tool to investigate the dynamic relations between peripheral sensory epithelia and central relay regions given its presence within olfactory fibers reaching the olfactory bulb (OB. Similarly, the use of thymidine analogues was able to show neurogenesis in an adult mammalian brain far before modern virus labelling and lipophilic tracers based methods. Nowadays, a wealth of new histochemical techniques combining cell and molecular biology approaches is available, giving stance to move from the analysis of the chemically identified circuitries to functional research. The study of adult neurogenesis is indeed one of the best explanatory examples of this statement. After defining the cell types involved and the basic physiology of this phenomenon in the OB plasticity, we can now analyze the role of neurogenesis in well testable behaviours related to socio-chemical communication in rodents.

  7. From chemical neuroanatomy to an understanding of the olfactory system

    Science.gov (United States)

    Oboti, L.; Peretto, P.; De Marchis, S.; Fasolo, A.

    2011-01-01

    The olfactory system of mammals is the appropriate model for studying several aspects of neuronal physiology spanning from the developmental stage to neural network remodelling in the adult brain. Both the morphological and physiological understanding of this system were strongly supported by classical histochemistry. It is emblematic the case of the Olfactory Marker Protein (OMP) staining, the first, powerful marker for fully differentiated olfactory receptor neurons and a key tool to investigate the dynamic relations between peripheral sensory epithelia and central relay regions given its presence within olfactory fibers reaching the olfactory bulb (OB). Similarly, the use of thymidine analogues was able to show neurogenesis in an adult mammalian brain far before modern virus labelling and lipophilic tracers based methods. Nowadays, a wealth of new histochemical techniques combining cell and molecular biology approaches is available, giving stance to move from the analysis of the chemically identified circuitries to functional research. The study of adult neurogenesis is indeed one of the best explanatory examples of this statement. After defining the cell types involved and the basic physiology of this phenomenon in the OB plasticity, we can now analyze the role of neurogenesis in well testable behaviours related to socio-chemical communication in rodents. PMID:22297441

  8. Energy saving during bulb storage applying modeling with computational fluid dynamics (CFD)

    Energy Technology Data Exchange (ETDEWEB)

    Sapounas, A.A.; Campen, J.B.; Wildschut, J.; Bot, G.P. [Wageningen UR Greenhouse Horticutlure and Applied Plant Research, Wageningen (Netherlands)

    2010-07-01

    Tulip bulbs are stored in ventilated containers to avoid high ethylene concentration between the bulbs. A commercial computational fluid dynamics (CFD) code was used in this study to examine the distribution of air flow between the containers and the potential energy saving by applying simple solutions concerning the design of the air inlet area and the adjustment of the ventilation rate. The variation in container ventilation was calculated to be between 60 and 180 per cent, with 100 per cent being the average flow through the containers. Various improvement measures were examined. The study showed that 7 per cent energy can be saved by smoothing the sharp corners of the entrance channels of the ventilation wall. The most effective and simple improvement was to cover the open top containers. In this case, the variation was between 80 and 120 per cent. The energy saving was about 38 per cent by adjusting the overall ventilation to the container with the minimal acceptable air flow.

  9. The olfactory gonadotropin-releasing hormone immunoreactive system in mouse.

    Science.gov (United States)

    Jennes, L

    1986-10-29

    The olfactory gonadotropin-releasing hormone (GnRH) system in mice was studied with immunofluorescence in combination with lesions of the olfactory bulb and retrograde transport of horseradish peroxidase (HRP) which was administered intravascularly, intranasally or into the subarachnoid space. GnRH-positive neurons were located in the two major branches forming the septal roots of the nervus terminalis, in the ganglion terminale, within the fascicles of the nervus terminalis throughout its extent, in a conspicuous band which connects the ventral neck of the caudal olfactory bulb with the accessory olfactory bulb and in the nasal mucosa. GnRH-positive fibers were seen in all areas in which neurons were found, i.e. in the rostral septum, the ganglion and nervus terminalis and in the nasal subepithelium. In addition, a broad bundle of fibers was observed to surround the entire caudal olfactory bulb, connecting the rostral sulcus rhinalis with the ventrocaudal olfactory bulb. Fibers were seen in close association with the main and accessory olfactory bulb, with the fila olfactoria and with the nasal mucosa. Throughout the olfactory bulb and the nasal epithelium, an association of GnRH fibers with blood vessels was apparent. Intravascular and intranasal injection of HRP resulted in labeling of certain GnRH neurons in the septal roots of the nervus terminalis, the ganglion terminale, the nervus terminalis, the caudal ventrodorsal connection and in the accessory olfactory bulb. After placement of HRP into the subarachnoid space dorsal to the accessory olfactory bulb, about 50% of the GnRH neurons in the accessory olfactory bulb and in the ventrodorsal connection were labeled with HRP. Also, a few GnRH neurons in the rostral septum, the ganglion terminale and in the fascicles of the nervus terminalis had taken up the enzyme. Lesions of the nervus terminalis caudal to the ganglion terminale resulted in sprouting of GnRH fibers at both sites of the knife cut. Lesions rostral

  10. Molecular modeling of ligand-receptor interactions in the OR5 olfactory receptor.

    Science.gov (United States)

    Singer, M S; Shepherd, G M

    1994-06-02

    Olfactory receptors belong to the superfamily of seven transmembrane domain, G protein-coupled receptors. In order to begin analysis of mechanisms of receptor activation, a computer model of the OR5 olfactory receptor has been constructed and compared with other members of this superfamily. We have tested docking of the odor molecule lyral, which is known to activate the OR5 receptor. The results point to specific ligand-binding residues on helices III through VII that form a binding pocket in the receptor. Some of these residues occupy sequence positions identical to ligand-binding residues conserved among other superfamily members. The results provide new insights into possible molecular mechanisms of odor recognition and suggest hypotheses to guide future experimental studies using site-directed mutagenesis.

  11. Olfactory Information Processing in the Drosophila Antennal Lobe : Anything Goes?

    OpenAIRE

    Silbering, Ana F.; Okada, Ryuichi; Ito, Kei; Galizia, Cosmas Giovanni

    2008-01-01

    When an animal smells an odor, olfactory sensory neurons generate an activity pattern across olfactory glomeruli of the first sensory neuropil, the insect antennal lobe or the vertebrate olfactory bulb. Here, several networks of local neurons interact with sensory neurons and with output neurons-insect projection neurons, or vertebrate mitral/tufted cells. The extent and form of information processing taking place in these local networks has been subject of controversy. To investigate the ro...

  12. Olfactory Memory

    Science.gov (United States)

    Eichenbaum, Howard; Robitsek, R. Jonathan

    2009-01-01

    Odor-recognition memory in rodents may provide a valuable model of cognitive aging. In a recent study we used signal detection analyses to distinguish odor recognition based on recollection versus that based on familiarity. Aged rats were selectively impaired in recollection, with relative sparing of familiarity, and the deficits in recollection were correlated with spatial memory impairments. These results complement electro-physiological findings indicating age-associated deficits in the ability of hippocampal neurons to differentiate contextual information, and this information-processing impairment may underlie the common age-associated decline in olfactory and spatial memory. PMID:19686208

  13. Routine magnetic resonance imaging for idiopathic olfactory loss: a modeling-based economic evaluation.

    Science.gov (United States)

    Rudmik, Luke; Smith, Kristine A; Soler, Zachary M; Schlosser, Rodney J; Smith, Timothy L

    2014-10-01

    Idiopathic olfactory loss is a common clinical scenario encountered by otolaryngologists. While trying to allocate limited health care resources appropriately, the decision to obtain a magnetic resonance imaging (MRI) scan to investigate for a rare intracranial abnormality can be difficult. To evaluate the cost-effectiveness of ordering routine MRI in patients with idiopathic olfactory loss. We performed a modeling-based economic evaluation with a time horizon of less than 1 year. Patients included in the analysis had idiopathic olfactory loss defined by no preceding viral illness or head trauma and negative findings of a physical examination and nasal endoscopy. Routine MRI vs no-imaging strategies. We developed a decision tree economic model from the societal perspective. Effectiveness, probability, and cost data were obtained from the published literature. Litigation rates and costs related to a missed diagnosis were obtained from the Physicians Insurers Association of America. A univariate threshold analysis and multivariate probabilistic sensitivity analysis were performed to quantify the degree of certainty in the economic conclusion of the reference case. The comparative groups included those who underwent routine MRI of the brain with contrast alone and those who underwent no brain imaging. The primary outcome was the cost per correct diagnosis of idiopathic olfactory loss. The mean (SD) cost for the MRI strategy totaled $2400.00 ($1717.54) and was effective 100% of the time, whereas the mean (SD) cost for the no-imaging strategy totaled $86.61 ($107.40) and was effective 98% of the time. The incremental cost-effectiveness ratio for the MRI strategy compared with the no-imaging strategy was $115 669.50, which is higher than most acceptable willingness-to-pay thresholds. The threshold analysis demonstrated that when the probability of having a treatable intracranial disease process reached 7.9%, the incremental cost-effectiveness ratio for MRI vs no

  14. Nervus terminalis, olfactory nerve, and optic nerve representation of luteinizing hormone-releasing hormone in primates.

    Science.gov (United States)

    Witkin, J W

    1987-01-01

    The luteinizing hormone-releasing hormone (LHRH) system was examined immunocytochemically in olfactory bulbs of adult monkeys, including two New World species (squirrel monkey, Saimiri sciureus and owl monkey, Aotus trivirgatus) and one Old World species (cynomolgus macaque, Macaca fasciculata), and in the brain and nasal region of a fetal rhesus macaque Macaca mulatta. LHRH neurons and fibers were found sparsely distributed in the olfactory bulbs in all adult monkeys. There was more LHRH in the accessory olfactory bulb (which is absent in Old World monkeys). In the fetal macaque there was a rich distribution of LHRH neurons and fibers along the pathway of the nervus terminalis, anterior and ventral to the olfactory bulb, and in the nasal septum, with fibers branching into the olfactory epithelium. In addition, there were LHRH neurons and fibers in the optic nerve.

  15. Olfactory nerve--a novel invasion route of Neisseria meningitidis to reach the meninges.

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    Hong Sjölinder

    Full Text Available Neisseria meningitidis is a human-specific pathogen with capacity to cause septic shock and meningitis. It has been hypothesized that invasion of the central nervous system (CNS is a complication of a bacteremic condition. In this study, we aimed to characterize the invasion route of N. meningitidis to the CNS. Using an intranasally challenged mouse disease model, we found that twenty percent of the mice developed lethal meningitis even though no bacteria could be detected in blood. Upon bacterial infection, epithelial lesions and redistribution of intracellular junction protein N-cadherin were observed at the nasal epithelial mucosa, especially at the olfactory epithelium, which is functionally and anatomically connected to the CNS. Bacteria were detected in the submucosa of the olfactory epithelium, along olfactory nerves in the cribriform plate, at the olfactory bulb and subsequently at the meninges and subarachnoid space. Furthermore, our data suggest that a threshold level of bacteremia is required for the development of meningococcal sepsis. Taken together, N. meningitidis is able to pass directly from nasopharynx to meninges through the olfactory nerve system. This study enhances our understanding how N. meningitidis invades the meninges. The nasal olfactory nerve system may be a novel target for disease prevention that can improve outcome and survival.

  16. Olfactory nerve--a novel invasion route of Neisseria meningitidis to reach the meninges.

    Science.gov (United States)

    Sjölinder, Hong; Jonsson, Ann-Beth

    2010-11-18

    Neisseria meningitidis is a human-specific pathogen with capacity to cause septic shock and meningitis. It has been hypothesized that invasion of the central nervous system (CNS) is a complication of a bacteremic condition. In this study, we aimed to characterize the invasion route of N. meningitidis to the CNS. Using an intranasally challenged mouse disease model, we found that twenty percent of the mice developed lethal meningitis even though no bacteria could be detected in blood. Upon bacterial infection, epithelial lesions and redistribution of intracellular junction protein N-cadherin were observed at the nasal epithelial mucosa, especially at the olfactory epithelium, which is functionally and anatomically connected to the CNS. Bacteria were detected in the submucosa of the olfactory epithelium, along olfactory nerves in the cribriform plate, at the olfactory bulb and subsequently at the meninges and subarachnoid space. Furthermore, our data suggest that a threshold level of bacteremia is required for the development of meningococcal sepsis. Taken together, N. meningitidis is able to pass directly from nasopharynx to meninges through the olfactory nerve system. This study enhances our understanding how N. meningitidis invades the meninges. The nasal olfactory nerve system may be a novel target for disease prevention that can improve outcome and survival.

  17. Olfactory Nerve—A Novel Invasion Route of Neisseria meningitidis to Reach the Meninges

    Science.gov (United States)

    Sjölinder, Hong; Jonsson, Ann-Beth

    2010-01-01

    Neisseria meningitidis is a human-specific pathogen with capacity to cause septic shock and meningitis. It has been hypothesized that invasion of the central nervous system (CNS) is a complication of a bacteremic condition. In this study, we aimed to characterize the invasion route of N. meningitidis to the CNS. Using an intranasally challenged mouse disease model, we found that twenty percent of the mice developed lethal meningitis even though no bacteria could be detected in blood. Upon bacterial infection, epithelial lesions and redistribution of intracellular junction protein N-cadherin were observed at the nasal epithelial mucosa, especially at the olfactory epithelium, which is functionally and anatomically connected to the CNS. Bacteria were detected in the submucosa of the olfactory epithelium, along olfactory nerves in the cribriform plate, at the olfactory bulb and subsequently at the meninges and subarachnoid space. Furthermore, our data suggest that a threshold level of bacteremia is required for the development of meningococcal sepsis. Taken together, N. meningitidis is able to pass directly from nasopharynx to meninges through the olfactory nerve system. This study enhances our understanding how N. meningitidis invades the meninges. The nasal olfactory nerve system may be a novel target for disease prevention that can improve outcome and survival. PMID:21124975

  18. Residue conservation and dimer-interface analysis of olfactory receptor molecular models

    Directory of Open Access Journals (Sweden)

    Ramanathan Sowdhamini

    2012-10-01

    Full Text Available Olfactory Receptors (ORs are members of the Class A rhodopsin like G-protein coupled receptors (GPCRs which are the initial players in the signal transduction cascade, leading to the generation of nerve impulses transmitted to the brain and resulting in the detection of odorant molecules. Despite the accumulation of thousands of olfactory receptor sequences, no crystal structures of ORs are known tο date. However, the recent availability of crystallographic models of a few GPCRs allows us to generate homology models of ORs and analyze their amino acid patterns, as there is a huge diversity in OR sequences. In this study, we have generated three-dimensional models of 100 representative ORs from Homo sapiens, Mus musculus, Drosophila melanogaster, Caenorhabditis elegans and Sacharomyces cerevisiae which were selected on the basis of a composite classification scheme and phylogenetic analysis. The crystal structure of bovine rhodopsin was used as a template and it was found that the full-length models have more than 90% of their residues in allowed regions of the Ramachandran plot. The structures were further used for analysis of conserved residues in the transmembrane and extracellular loop regions in order to identify functionally important residues. Several ORs are known to be functional as dimers and hence dimer interfaces were predicted for OR models to analyse their oligomeric functional state.

  19. Altered ingestive behavior, weight changes, and intact olfactory sense in an APP overexpression model.

    Science.gov (United States)

    Vloeberghs, Ellen; Van Dam, Debby; Franck, Frieda; Serroyen, Jan; Geert, Molenberghs; Staufenbiel, Matthias; De Deyn, Peter Paul

    2008-06-01

    Transgenic APP23 mice were generated to model Alzheimer's disease. The APP23 model develops pathological features, learning deficits, and memory deficits analogous to dementing patients. In this report, transgenic mice exhibited several behavioral disturbances indicating the presence of neuropsychiatric symptoms of dementia. Aiming to verify whether the model also develops other behavioral problems, the authors investigated ingestive behavior in APP23 males of 3, 6 and 12 months. In addition, body weights of a naive male group were longitudinally monitored starting at weaning. Olfactory acuity was evaluated in mice of different age groups. Although olfactory functioning of APP23 mice appeared intact, they drank more and took more food pellets compared with wild-type littermates during a 1-week registration period. From the age of 4.5 weeks onward, APP23 males weighed significantly less than their control littermates, whereas this difference became more prominent with increasing age. Our results suggest the presence of a hypermetabolic state in this model. This is the first report, evidencing the presence of changes in eating and drinking behavior in a single transgenic Alzheimer mouse model. (Copyright) 2008 APA, all rights reserved.

  20. Correlation of olfactory dysfunction of different etiologies in MRI and comparison with subjective and objective olfactometry

    International Nuclear Information System (INIS)

    Goektas, Oender; Fleiner, Franca; Sedlmaier, Benedikt; Bauknecht, Christian

    2009-01-01

    Background: The clinical diagnosis of olfactory dysfunction of different etiologies has been standardized by the German Working Group of Olfactology and Gustology, but there is no agreement about the most suitable imaging modality for diagnosing this disorder. Material and methods: A total of 24 patients (13 women, 11 men; mean age 52 years) with different types of olfactory dysfunction (anosmia, hyposmia) were examined by objective and subjective olfactometry and magnetic resonance imaging (MRI) of the olfactory bulb. Results: There was a positive correlation between objective olfactometry and volumetry of the olfactory bulb but no correlation between subjective olfactometry and MRI. Conclusion: MRI allows an evaluation of the olfactory bulb and appears to be superior to other modalities such as computed tomography (CT). Objective olfactometry remains the gold standard for reliable diagnosis of olfactory dysfunction.

  1. Olfactory memory: a bridge between humans and animals in models of cognitive aging.

    Science.gov (United States)

    Eichenbaum, Howard; Robitsek, R Jonathan

    2009-07-01

    Odor-recognition memory in rodents may provide a valuable model of cognitive aging. In a recent study we used signal detection analyses to distinguish odor recognition based on recollection versus that based on familiarity. Aged rats were selectively impaired in recollection, with relative sparing of familiarity, and the deficits in recollection were correlated with spatial memory impairments. These results complement electrophysiological findings indicating age-associated deficits in the ability of hippocampal neurons to differentiate contextual information, and this information-processing impairment may underlie the common age-associated decline in olfactory and spatial memory.

  2. The usefulness of olfactory fear conditioning for the study of early emotional and cognitive impairment in reserpine model.

    Science.gov (United States)

    Souza, Rimenez R; França, Sanmara L; Bessa, Marília M; Takahashi, Reinaldo N

    2013-11-01

    Due to the ability for depleting neuronal storages of monoamines, the reserpine model is a suitable approach for the investigation of the neurobiology of neurodegenerative diseases. However, the behavioral effects of low doses of reserpine are not always detected by classic animal tests of cognition, emotion, and sensory ability. In this study, the effects of reserpine (0.5-1.0mg/kg) were evaluated in olfactory fear conditioning, inhibitory avoidance, open-field, elevated plus-maze, and olfactory discrimination. Possible protective effects were also investigated. We found that single administration of reserpine impaired the acquisition of olfactory fear conditioning (in both doses) as well as olfactory discrimination (in the higher dose), while no effects were seen in all other tests. Additionally, we demonstrated that prior exposure to environmental enrichment prevented effects of reserpine in animals tested in olfactory fear conditioning. Altogether, these findings suggest that a combined cognitive, emotional and sensory-dependent task would be more sensitive to the effects of the reserpine model. In addition, the present data support the environmental enrichment as an useful approach for the study of resilience mechanisms in neurodegenerative processes. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. Phylogenic aspects of the amphibian dual olfactory system.

    Science.gov (United States)

    Taniguchi, Kazumi; Saito, Shouichiro; Oikawa, Toshihiro; Taniguchi, Kazuyuki

    2008-01-01

    The phylogenic significance of the subdivision of dual olfactory system is reviewed mainly on the basis of our findings by electron microscopy and lectin histochemistry in the three amphibian species. The dual olfactory system is present in common in these species and consists of the projection from the olfactory epithelium (OE) to the main olfactory bulb (MOB) and that from the vomeronasal epithelium (VNE) to the accessory olfactory bulb (AOB). The phylogenic significance of subdivisions in the dual olfactory system in the amphibian must differently be interpreted. The subdivision of the MOB into its dorsal region (D-MOB) and ventral region (V-MOB) in Xenopus laevis must be attributed to the primitive features in their olfactory receptors. The middle cavity epithelium lining the middle cavity of this frog possesses both ciliated sensory cells and microvillous sensory cells, reminding the OE in fish. The subdivision of the AOB into the rostral (R-AOB) and caudal part (C-AOB) in Bufo japonicus formosus must be regarded as an advanced characteristic. The lack of subdivisions in both MOB and AOB in Cynops pyrrhogaster may reflect their phylogenic primitiveness. Since our lectin histochemistry to detect glycoconjugates expressed in the olfactory pathway reveals the subdivisions in the dual olfactory system in the amphibian, the glycoconjugates may deeply participate in the organization and function of olfactory pathways in phylogeny.

  4. Olfactory Impact of Higher Alcohols on Red Wine Fruity Ester Aroma Expression in Model Solution.

    Science.gov (United States)

    Cameleyre, Margaux; Lytra, Georgia; Tempere, Sophie; Barbe, Jean-Christophe

    2015-11-11

    This study focused on the impact of five higher alcohols on the perception of fruity aroma in red wines. Various aromatic reconstitutions were prepared, consisting of 13 ethyl esters and acetates and 5 higher alcohols, all at the average concentrations found in red wine. These aromatic reconstitutions were prepared in several matrices. Sensory analysis revealed the interesting behavior of certain compounds among the five higher alcohols following their individual addition or omission. The "olfactory threshold" of the fruity pool was evaluated in several matrices: dilute alcohol solution, dilute alcohol solution containing 3-methylbutan-1-ol or butan-1-ol individually, and dilute alcohol solution containing the mixture of five higher alcohols, blended together at various concentrations. The presence of 3-methylbutan-1-ol or butan-1-ol alone led to a significant decrease in the "olfactory threshold" of the fruity reconstitution, whereas the mixture of alcohols raised the olfactory threshold. Sensory profiles highlighted changes in the perception of fruity nuances in the presence of the mixture of higher alcohols, with specific perceptive interactions, including a relevant masking effect on fresh- and jammy-fruit notes of the fruity mixture in both dilute alcohol solution and dearomatized red wine matrices. When either 3-methylbutan-1-ol or butan-1-ol was added to the fruity reconstitution in dilute alcohol solution, an enhancement of butyric notes was reported with 3-methylbutan-1-ol and fresh- and jammy-fruit with butan-1-ol. This study, the first to focus on the impact of higher alcohols on fruity aromatic expression, revealed that these compounds participate, both quantitatively and qualitatively, in masking fruity aroma perception in a model fruity wine mixture.

  5. Modulation of olfactory sensitivity and glucose sensing by the feeding state in obese Zucker rats.

    Directory of Open Access Journals (Sweden)

    Pascaline eAimé

    2014-09-01

    Full Text Available The Zucker fa/fa rat has been widely used as an animal model to study obesity, since it recapitulates most of its behavioral and metabolic dysfunctions, such as hyperphagia, hyperglycemia and insulin resistance. Although it is well established that olfaction is under nutritional and hormonal influences, little is known about the impact of metabolic dysfunctions on olfactory performances and glucose-sensing in the olfactory system of the obese Zucker rat. In the present study, using a behavioral paradigm based on a conditioned olfactory aversion, we have shown that both obese and lean Zucker rats have a better olfactory sensitivity when they are fasted than when they are satiated. Interestingly, the obese Zucker rats displayed a higher olfactory sensitivity than their lean controls. By investigating the molecular mechanisms involved in glucose-sensing in the olfactory system, we demonstrated that sodium-coupled glucose transporters 1 (SGLT1 and insulin dependent glucose transporters 4 (GLUT4 are both expressed in the olfactory bulb (OB. By comparing the expression of GLUT4 and SGLT1 in OB of obese and lean Zucker rats, we found that only SGLT1 is regulated in genotype-dependent manner. Next, we used glucose oxidase biosensors to simultaneously measure in vivo the extracellular fluid glucose concentrations ([Gluc]ECF in the OB and the cortex. Under metabolic steady state, we have determined that the OB contained twice the amount of glucose found in the cortex. In both regions, the [Gluc]ECF was 2 fold higher in obese rats compared to their lean controls. Under induced dynamic glycemia conditions, insulin injection produced a greater decrease of [Gluc]ECF in the OB than in the cortex. Glucose injection did not affect OB [Gluc]ECF in Zucker fa/fa rats. In conclusion, these results emphasize the importance of glucose for the OB network function and provide strong arguments towards establishing the OB glucose-sensing as a key factor for sensory

  6. Development of a model and test equipment for cold flow tests at 500 atm of small nuclear light bulb configurations

    Science.gov (United States)

    Jaminet, J. F.

    1972-01-01

    A model and test equipment were developed and cold-flow-tested at greater than 500 atm in preparation for future high-pressure rf plasma experiments and in-reactor tests with small nuclear light bulb configurations. With minor exceptions, the model chamber is similar in design and dimensions to a proposed in-reactor geometry for tests with fissioning uranium plasmas in the nuclear furnace. The model and the equipment were designed for use with the UARL 1.2-MW rf induction heater in tests with rf plasmas at pressures up to 500 atm. A series of cold-flow tests of the model was then conducted at pressures up to about 510 atm. At 504 atm, the flow rates of argon and cooling water were 3.35 liter/sec (STP) and 26 gal/min, respectively. It was demonstrated that the model is capable of being operated for extended periods at the 500-atm pressure level and is, therefore, ready for use in initial high-pressure rf plasma experiments.

  7. Effects of radiotherapy on olfactory function

    International Nuclear Information System (INIS)

    Hoelscher, Tobias; Seibt, Annedore; Appold, Steffen; Doerr, Wolfgang; Herrmann, Thomas; Huettenbrink, Karl-Bernd; Hummel, Thomas

    2005-01-01

    Background and Purpose: Changes in olfactory function have been reported in patients receiving significant doses of radiation to the olfactory epithelium. Aim of this study was to investigate severity and time course of changes in olfactory function in patients irradiated for tumours of the head and neck region. Material and Methods: Forty-four patients receiving radiotherapy (RT) for tumours in the area of the head and neck participated (16 women, 28 men; age 11-81 y; mean 55 y). Olfactory function was measured before and bi-weekly during RT for 6 weeks. A subgroup (25 patients) was followed for 12 months. Patients were divided into two groups according to the dose to the olfactory epithelium. Twenty-two patients ('OLF group') had radiation doses to the olfactory epithelium between 23.7 and 79.5 Gy (median 62.2 Gy). In the 22 patients of the 'non-OLF group' the dose applied to the olfactory epithelium was significantly lower (2.9-11.1 Gy, median 5.9 Gy). Total tumour dose (30-76.8 Gy), age, sex distribution, and baseline chemosensory function were not significantly different between groups. Testing was performed for odour identification, odour discrimination, and olfactory thresholds. Results: Odour discrimination, but not odour identification or odour threshold, was significantly decreased 2-6 weeks after begin of therapy in the OLF group. In addition, a significant effect of the radiation dose was observed for odour discrimination. More than 6 months after therapy, OLF group patients had significantly lower odour identification scores compared to the non-OLF group. Conclusion: As indicated through the non-significant change of olfactory thresholds, the olfactory epithelium is relatively resistant against effects of radiation. It is hypothesized that RT has additional effects on the olfactory bulb/orbitofrontal cortex responsible for the observed changes of suprathreshold olfactory function

  8. Microencapsulation improves inhibitory effects of transplanted olfactory ensheathing cells on pain after sciatic nerve injury

    Directory of Open Access Journals (Sweden)

    Hao Zhao

    2015-01-01

    Full Text Available Olfactory bulb tissue transplantation inhibits P2X2/3 receptor-mediated neuropathic pain. However, the olfactory bulb has a complex cellular composition, and the mechanism underlying the action of purified transplanted olfactory ensheathing cells (OECs remains unclear. In the present study, we microencapsulated OECs in alginic acid, and transplanted free and microencapsulated OECs into the region surrounding the injured sciatic nerve in rat models of chronic constriction injury. We assessed mechanical nociception in the rat models 7 and 14 days after surgery by measuring paw withdrawal threshold, and examined P2X2/3 receptor expression in L 4-5 dorsal root ganglia using immunohistochemistry. Rats that received free and microencapsulated OEC transplants showed greater withdrawal thresholds than untreated model rats, and weaker P2X2/3 receptor immunoreactivity in dorsal root ganglia. At 14 days, paw withdrawal threshold was much higher in the microencapsulated OEC-treated animals. Our results confirm that microencapsulated OEC transplantation suppresses P2X2/3 receptor expression in L 4-5 dorsal root ganglia in rat models of neuropathic pain and reduces allodynia, and also suggest that transplantation of microencapsulated OECs is more effective than transplantation of free OECs for the treatment of neuropathic pain.

  9. Dynamical modeling of the moth pheromone-sensitive olfactory receptor neuron within its sensillar environment.

    Directory of Open Access Journals (Sweden)

    Yuqiao Gu

    Full Text Available In insects, olfactory receptor neurons (ORNs, surrounded with auxiliary cells and protected by a cuticular wall, form small discrete sensory organs--the sensilla. The moth pheromone-sensitive sensillum is a well studied example of hair-like sensillum that is favorable to both experimental and modeling investigations. The model presented takes into account both the molecular processes of ORNs, i.e. the biochemical reactions and ionic currents giving rise to the receptor potential, and the cellular organization and compartmentalization of the organ represented by an electrical circuit. The number of isopotential compartments needed to describe the long dendrite bearing pheromone receptors was determined. The transduction parameters that must be modified when the number of compartments is increased were identified. This model reproduces the amplitude and time course of the experimentally recorded receptor potential. A first complete version of the model was analyzed in response to pheromone pulses of various strengths. It provided a quantitative description of the spatial and temporal evolution of the pheromone-dependent conductances, currents and potentials along the outer dendrite and served to determine the contribution of the various steps in the cascade to its global sensitivity. A second simplified version of the model, utilizing a single depolarizing conductance and leak conductances for repolarizing the ORN, was derived from the first version. It served to analyze the effects on the sensory properties of varying the electrical parameters and the size of the main sensillum parts. The consequences of the results obtained on the still uncertain mechanisms of olfactory transduction in moth ORNs--involvement or not of G-proteins, role of chloride and potassium currents--are discussed as well as the optimality of the sensillum organization, the dependence of biochemical parameters on the neuron spatial extension and the respective contributions

  10. An information theoretic model of information processing in the Drosophila olfactory system: the role of inhibitory neurons for system efficiency.

    Science.gov (United States)

    Faghihi, Faramarz; Kolodziejski, Christoph; Fiala, André; Wörgötter, Florentin; Tetzlaff, Christian

    2013-12-20

    Fruit flies (Drosophila melanogaster) rely on their olfactory system to process environmental information. This information has to be transmitted without system-relevant loss by the olfactory system to deeper brain areas for learning. Here we study the role of several parameters of the fly's olfactory system and the environment and how they influence olfactory information transmission. We have designed an abstract model of the antennal lobe, the mushroom body and the inhibitory circuitry. Mutual information between the olfactory environment, simulated in terms of different odor concentrations, and a sub-population of intrinsic mushroom body neurons (Kenyon cells) was calculated to quantify the efficiency of information transmission. With this method we study, on the one hand, the effect of different connectivity rates between olfactory projection neurons and firing thresholds of Kenyon cells. On the other hand, we analyze the influence of inhibition on mutual information between environment and mushroom body. Our simulations show an expected linear relation between the connectivity rate between the antennal lobe and the mushroom body and firing threshold of the Kenyon cells to obtain maximum mutual information for both low and high odor concentrations. However, contradicting all-day experiences, high odor concentrations cause a drastic, and unrealistic, decrease in mutual information for all connectivity rates compared to low concentration. But when inhibition on the mushroom body is included, mutual information remains at high levels independent of other system parameters. This finding points to a pivotal role of inhibition in fly information processing without which the system efficiency will be substantially reduced.

  11. Anatomy, histochemistry and immunohistochemistry of the olfactory subsystems in mice

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    Arthur William Barrios

    2014-07-01

    Full Text Available The four regions of the murine nasal cavity featuring olfactory neurons were studied anatomically and by labelling with lectins and relevant antibodies with a view to establishing criteria for the identification of olfactory subsystems that are readily applicable to other mammals. In the main olfactory epithelium and the septal organ the olfactory sensory neurons (OSNs are embedded in quasi-stratified columnar epithelium; vomeronasal OSNs are embedded in epithelium lining the medial interior wall of the vomeronasal duct and do not make contact with the mucosa of the main nasal cavity; and in Grüneberg’s ganglion a small isolated population of OSNs lies adjacent to, but not within, the epithelium. With the exception of Grüneberg’s ganglion, all the tissues expressing olfactory marker protein (OMP (the above four nasal territories, the vomeronasal and main olfactory nerves, and the main and accessory olfactory bulbs are also labelled by Lycopersicum esculentum agglutinin, while Ulex europaeus agglutinin I labels all and only tissues expressing Gi2 (the apical sensory neurons of the vomeronasal organ, their axons, and their glomerular destinations in the anterior accessory olfactory bulb. These staining patterns of UEA-I and LEA may facilitate the characterization of olfactory anatomy in other species. A 710-section atlas of the anatomy of the murine nasal cavity has been made available on line.

  12. Olfactory nerve transport of macromolecular drugs to the brain. A problem in olfactory impaired patients

    International Nuclear Information System (INIS)

    Shiga, Hideaki; Yamamoto, Junpei; Miwa, Takaki

    2012-01-01

    Nasal administration of macromolecular drugs (including peptides and nanoparticles) has the potential to enable drug delivery system beyond the blood brain barrier (BBB) via olfactory nerve transport. Basic research on drug deliver systems to the brain via nasal administration has been well reported. Insulin-like growth factor-I (IGF-I) is associated with the development and growth of the central nervous system. Clinical application of IGF-I with nasal administration is intended to enable drug delivery to brain through the BBB. Uptake of IGF-I in the olfactory bulb and central nervous system increased according to the dosage of nasally administered IGF-I in normal ICR mice, however IGF-I uptake in the trigeminal nerve remained unchanged. Olfactory nerve transport is important for the delivery of nasally administered IGF-I to the brain in vivo. Because a safe olfactory nerve tracer has not been clinically available, olfactory nerve transport has not been well studied in humans. Nasal thallium-201 ( 201 Tl) administration has been safely used to assess the direct pathway to the brain via the nose in healthy volunteers with a normal olfactory threshold. 201 Tl olfactory nerve transport has recently been shown to decrease in patients with hyposmia. The olfactory nerve transport function in patients with olfactory disorders will be determined using 201 Tl olfacto-scintigraphy for the exclusion of candidates in a clinical trial to assess the usefulness of nasal administration of IGF-I. (author)

  13. Olfactory dreams, olfactory interest, and imagery : Relationships to olfactory memory

    OpenAIRE

    Arshamian, Artin

    2007-01-01

    Existing evidence for olfactory imagery is mixed and mainly based on reports from hallucinations and volitional imagery. Using a questionnaire, Stevenson and Case (2005) showed that olfactory dreams provided a good source for olfactory imagery studies. This study applied an extended version of the same questionnaire and examined olfactory dreams and their relation to real-life experienced odors, volitional imagery, and olfactory interest. Results showed that olfactory dreams were similar to r...

  14. Uptake and transport of manganese in primary and secondary olfactory neurones in pike.

    Science.gov (United States)

    Tjälve, H; Mejàre, C; Borg-Neczak, K

    1995-07-01

    gamma-spectrometry and autoradiography were used to examine the axoplasmic flow of manganese in the olfactory nerves and to study the uptake of the metal in the brain after application of 54Mn2+ in the olfactory chambers of pikes. The results show that the 54Mn2+ is taken up in the olfactory receptor cells and is transported at a constant rate along the primary olfactory neurones into the brain. The maximal velocity for the transported 54Mn2+ was 2.90 +/- 0.21 mm/hr (mean +/- S.E.) at 10 degrees, which was the temperature used in the experiments. The 54Mn2+ accumulated in the entire olfactory bulbs, although most marked in central and caudal parts. The metal was also seen to migrate into large areas of the telencephalon, apparently mainly via the secondary olfactory axons present in the medial olfactory tract. A transfer along fibres of the medial olfactory tract probably also explains the labelling which was seen in the diencephalon down to the hypothalamus. The results also showed that there is a pathway connecting the two olfactory bulbs of the pike and that this can carry the metal. Our data further showed a marked accumulation of 54Mn2+ in the meningeal epithelium and in the contents of the meningeal sacs surrounding the olfactory bulbs. It appears from our study that manganese has the ability to pass the synaptic junctions between the primary and the secondary olfactory neurones in the olfactory bulbs and to migrate along secondary olfactory pathways into the telencephalon and the diencephalon.(ABSTRACT TRUNCATED AT 250 WORDS)

  15. Localization of α1-2 Fucose Glycan in the Mouse Olfactory Pathway.

    Science.gov (United States)

    Kondoh, Daisuke; Kamikawa, Akihiro; Sasaki, Motoki; Kitamura, Nobuo

    2017-01-01

    Glycoconjugates in the olfactory system play critical roles in neuronal formation, and α1-2 fucose (α1-2Fuc) glycan mediates neurite outgrowth and synaptic plasticity. Histochemical findings of α1-2Fuc glycan in the mouse olfactory system detected using Ulex europaeus agglutinin-I (UEA-I) vary. This study histochemically assessed the main olfactory and vomeronasal pathways in male and female ICR and C57BL/6J mice aged 3-4 months using UEA-I. Ulex europaeus agglutinin-I reacted with most receptor cells arranged mainly at the basal region of the olfactory epithelium. The olfactory nerve layer and glomerular layer of the main olfactory bulb were speckled with positive UEA-I staining, and positive fibers were scattered from the glomerular to the internal plexiform layer. The lateral olfactory tract and rostral migratory stream were also positive for UEA-I. We identified superficial short-axon cells, interneurons of the external plexiform layer, external, middle and internal tufted cells, mitral cells and granule cells as the origins of the UEA-I-positive fibers in the main olfactory bulb. The anterior olfactory nucleus, anterior piriform cortex and olfactory tubercle were negative for UEA-I. Most receptor cells in the vomeronasal epithelium and most glomeruli of the accessory olfactory bulb were positive for UEA-I. Our findings indicated that α1-2Fuc glycan is located within the primary and secondary, but not the ternary, pathways of the main olfactory system, in local circuits of the main olfactory bulb and within the primary, but not secondary, pathway of the vomeronasal system. © 2016 S. Karger AG, Basel.

  16. Neuronal nitric oxide synthase in the olfactory system of an adult teleost fish Oreochromis mossambicus.

    Science.gov (United States)

    Singru, Praful S; Sakharkar, Amul J; Subhedar, Nishikant

    2003-07-11

    The aim of the present study is to explore the distribution of nitric oxide synthase in the olfactory system of an adult teleost, Oreochromis mossambicus using neuronal nitric oxide synthase (nNOS) immunocytochemistry and nicotinamide adenine dinucleotide phosphate diaphorase (NADPHd) histochemistry methods. Intense nNOS immunoreactivity was noticed in several olfactory receptor neurons (ORNs), in their axonal extensions over the olfactory nerve and in some basal cells of the olfactory epithelium. nNOS containing fascicles of the ORNs enter the bulb from its rostral pole, spread in the olfactory nerve layer in the periphery of the bulb and display massive innervation of the olfactory glomeruli. Unilateral ablation of the olfactory organ resulted in dramatic loss of nNOS immunoreactivity in the olfactory nerve layer of the ipsilateral bulb. In the olfactory bulb of intact fish, some granule cells showed intense immunoreactivity; dendrites arising from the granule cells could be traced to the glomerular layer. Of particular interest is the occurrence of nNOS immunoreactivity in the ganglion cells of the nervus terminalis. nNOS containing fibers were also encountered in the medial olfactory tracts as they extend to the telencephalon. The NADPHd staining generally coincides with that of nNOS suggesting that it may serve as a marker for nNOS in the olfactory system of this fish. However, mismatch was encountered in the case of mitral cells, while all are nNOS-negative, few were NADPHd positive. The present study for the first time revealed the occurrence of nNOS immunoreactivity in the ORNs of an adult vertebrate and suggests a role for nitric oxide in the transduction of odor stimuli, regeneration of olfactory epithelium and processing of olfactory signals.

  17. Changes in Olfactory Sensory Neuron Physiology and Olfactory Perceptual Learning After Odorant Exposure in Adult Mice.

    Science.gov (United States)

    Kass, Marley D; Guang, Stephanie A; Moberly, Andrew H; McGann, John P

    2016-02-01

    The adult olfactory system undergoes experience-dependent plasticity to adapt to the olfactory environment. This plasticity may be accompanied by perceptual changes, including improved olfactory discrimination. Here, we assessed experience-dependent changes in the perception of a homologous aldehyde pair by testing mice in a cross-habituation/dishabituation behavioral paradigm before and after a week-long ester-odorant exposure protocol. In a parallel experiment, we used optical neurophysiology to observe neurotransmitter release from olfactory sensory neuron (OSN) terminals in vivo, and thus compared primary sensory representations of the aldehydes before and after the week-long ester-odorant exposure in individual animals. Mice could not discriminate between the aldehydes during pre-exposure testing, but ester-exposed subjects spontaneously discriminated between the homologous pair after exposure, whereas home cage control mice cross-habituated. Ester exposure did not alter the spatial pattern, peak magnitude, or odorant-selectivity of aldehyde-evoked OSN input to olfactory bulb glomeruli, but did alter the temporal dynamics of that input to make the time course of OSN input more dissimilar between odorants. Together, these findings demonstrate that odor exposure can induce both physiological and perceptual changes in odor processing, and suggest that changes in the temporal patterns of OSN input to olfactory bulb glomeruli could induce differences in odor quality. © The Author 2015. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  18. Pattern Classification Using an Olfactory Model with PCA Feature Selection in Electronic Noses: Study and Application

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    Junbao Zheng

    2012-03-01

    Full Text Available Biologically-inspired models and algorithms are considered as promising sensor array signal processing methods for electronic noses. Feature selection is one of the most important issues for developing robust pattern recognition models in machine learning. This paper describes an investigation into the classification performance of a bionic olfactory model with the increase of the dimensions of input feature vector (outer factor as well as its parallel channels (inner factor. The principal component analysis technique was applied for feature selection and dimension reduction. Two data sets of three classes of wine derived from different cultivars and five classes of green tea derived from five different provinces of China were used for experiments. In the former case the results showed that the average correct classification rate increased as more principal components were put in to feature vector. In the latter case the results showed that sufficient parallel channels should be reserved in the model to avoid pattern space crowding. We concluded that 6~8 channels of the model with principal component feature vector values of at least 90% cumulative variance is adequate for a classification task of 3~5 pattern classes considering the trade-off between time consumption and classification rate.

  19. What a Nostril Knows: Olfactory Nerve-Evoked AMPA Responses Increase while NMDA Responses Decrease at 24-h Post-Training for Lateralized Odor Preference Memory in Neonate Rat

    Science.gov (United States)

    Yuan, Qi; Harley, Carolyn W.

    2012-01-01

    Increased AMPA signaling is proposed to mediate long-term memory. Rat neonates acquire odor preferences in a single olfactory bulb if one nostril is occluded at training. Memory testing here confirmed that only trained bulbs support increased odor preference at 24 h. Olfactory nerve field potentials were tested at 24 h in slices from trained and…

  20. Electrophysiological characterization of male goldfish (Carassius auratus ventral preoptic area neurons receiving olfactory inputs

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    Wudu E. Lado

    2014-06-01

    Full Text Available Chemical communication via sex pheromones is critical for successful reproduction but the underlying neural mechanisms are not well-understood. The goldfish is a tractable model because sex pheromones have been well-characterized in this species. We used male goldfish forebrain explants in vitro and performed whole-cell current clamp recordings from single neurons in the ventral preoptic area (vPOA to characterize their membrane properties and synaptic inputs from the olfactory bulbs (OB. Principle component and cluster analyses based on intrinsic membrane properties of vPOA neurons (N = 107 revealed five (I-V distinct cell groups. These cells displayed differences in their input resistance (Rinput: I II = IV > III = V. Evidence from electrical stimulation of the OB and application of receptor antagonists suggests that vPOA neurons receive monosynaptic glutamatergic inputs via the medial olfactory tract, with connectivity varying among neuronal groups [I (24%, II (40%, III (0%, IV (34% and V (2%].

  1. Neurobiology of mammalian olfactory learning that occurs during sensitive periods

    Directory of Open Access Journals (Sweden)

    Hideto KABA

    2010-12-01

    Full Text Available This review examines the organizational principles underlying olfactory learning in three specialized contexts that occur during sensitive periods of enhanced neural plasticity and emphasizes some of their common features. All three forms of olfactory learning are associated with neural changes in the olfactory bulb (OB at the first stage of sensory processing. These changes require the association of the olfactory and somatosensory signals in the OB. They all depend on somatosensory stimulation-induced release of noradrenaline that induces structural and functional changes at mitral-granule cell reciprocal synapses in the OB, resulting in increases in inhibitory transmission. In the accessory olfactory bulb, this represents the enhanced self-inhibition of mitral cells, which selectively disrupts the transmission of the mating male’s pregnancy-blocking signal at this level. In contrast, an extensive network of secondary dendrites of mitral cells in the main olfactory bulb probably results in a sharpening of the odor-induced pattern of activity, due to increases in lateral inhibition, leading to offspring recognition in sheep and neonatal learning in rats and rabbits. These findings show that inhibitory interneurons play a critical role in olfactory learning. Further work on how these neurons shape olfactory circuit function could provide important clues to understand memory functions of interneurons in other systems. Moreover, recent research has suggested that three forms of olfactory learning are controlled by synergistic, redundant, and distributed neural mechanisms. This has general implications regarding the mechanisms that may contribute to the robustness of memories [Current Zoology 56 (6: 819–833, 2010].

  2. Neuropeptide Y in the olfactory system, forebrain and pituitary of the teleost, Clarias batrachus.

    Science.gov (United States)

    Gaikwad, Archana; Biju, K C; Saha, Subhash G; Subhedar, Nishikant

    2004-03-01

    Distribution of neuropeptide Y (NPY)-like immunoreactivity in the forebrain of catfish Clarias batrachus was examined with immunocytochemistry. Conspicuous immunoreactivity was seen in the olfactory receptor neurons (ORNs), their projections in the olfactory nerve, fascicles of the olfactory nerve layer in the periphery of bulb and in the medial olfactory tracts as they extend to the telencephalic lobes. Ablation of the olfactory organ resulted in loss of immunoreactivity in the olfactory nerve layer of the bulb and also in the fascicles of the medial olfactory tracts. This evidence suggests that NPY may serve as a neurotransmitter in the ORNs and convey chemosensory information to the olfactory bulb, and also to the telencephalon over the extrabulbar projections. In addition, network of beaded immunoreactive fibers was noticed throughout the olfactory bulb, which did not respond to ablation experiment. These fibers may represent centrifugal innervation of the bulb. Strong immunoreactivity was encountered in some ganglion cells of nervus terminalis. Immunoreactive fibers and terminal fields were widely distributed in the telencephalon. Several neurons of nucleus entopeduncularis were moderately immunoreactive; and a small population of neurons in nucleus preopticus periventricularis was also labeled. Immunoreactive terminal fields were particularly conspicuous in the preoptic, the tuberal areas, and the periventricular zone around the third ventricle and inferior lobes. NPY immunoreactive cells and fibers were detected in all the lobes of the pituitary gland. Present results describing the localization of NPY in the forebrain of C. batrachus are in concurrence with the pattern of the immunoreactivity encountered in other teleosts. However, NPY in olfactory system of C. batrachus is a novel feature that suggests a role for the peptide in processing of chemosensory information.

  3. The Heat Strain of Various Athletic Surfaces: A Comparison Between Observed and Modeled Wet-Bulb Globe Temperatures.

    Science.gov (United States)

    Pryor, J Luke; Pryor, Riana R; Grundstein, Andrew; Casa, Douglas J

    2017-11-01

      The National Athletic Trainers' Association recommends using onsite wet-bulb globe temperature (WBGT) measurement to determine whether to modify or cancel physical activity. However, not all practitioners do so and instead they may rely on the National Weather Service (NWS) to monitor weather conditions.   To compare regional NWS WBGT estimates with local athletic-surface readings and compare WBGT measurements among various local athletic surfaces.   Observational study.   Athletic fields.   Measurements from 2 identical WBGT devices were averaged on 10 athletic surfaces within an NWS station reporting radius. Athletic surfaces consisted of red and black all-weather tracks (track), blue and black hard tennis courts (tennis), nylon-knit artificial green turf, green synthetic turfgrass, volleyball sand, softball clay, natural grass (grass), and a natural lake (water). Measurements (n = 143 data pairs) were taken over 18 days (May through September) between 1 pm and 4:30 pm in direct sunlight 1.2 m above ground. The starting location was counterbalanced across surfaces. The NWS weather data were entered into an algorithm to model NWS WBGT.   Black tennis, black track, red track, and volleyball sand WBGT recordings were greater than NWS estimates ( P ≤ .05). When all athletic-surface measurements were combined, NWS (26.85°C ± 2.93°C) underestimated athletic-surface WBGT measurements (27.52°C ± 3.13°C; P < .001). The range of difference scores (-4.42°C to 6.14°C) and the absolute mean difference (1.71°C ± 1.32°C) were large. The difference between the onsite and NWS WBGT measurements resulted in misclassification of the heat-safety activity category 45% (65/143) of the time ([Formula: see text]= 3.857, P = .05). The WBGT of water was 1.4°C to 2.7°C lower than that of all other athletic surfaces ( P = .04). We observed no other differences among athletic surfaces but noted large WBGT measurement variability among athletic playing surfaces.

  4. Lateral presynaptic inhibition mediates gain control in an olfactory circuit.

    Science.gov (United States)

    Olsen, Shawn R; Wilson, Rachel I

    2008-04-24

    Olfactory signals are transduced by a large family of odorant receptor proteins, each of which corresponds to a unique glomerulus in the first olfactory relay of the brain. Crosstalk between glomeruli has been proposed to be important in olfactory processing, but it is not clear how these interactions shape the odour responses of second-order neurons. In the Drosophila antennal lobe (a region analogous to the vertebrate olfactory bulb), we selectively removed most interglomerular input to genetically identified second-order olfactory neurons. Here we show that this broadens the odour tuning of these neurons, implying that interglomerular inhibition dominates over interglomerular excitation. The strength of this inhibitory signal scales with total feedforward input to the entire antennal lobe, and has similar tuning in different glomeruli. A substantial portion of this interglomerular inhibition acts at a presynaptic locus, and our results imply that this is mediated by both ionotropic and metabotropic receptors on the same nerve terminal.

  5. Linking adult olfactory neurogenesis to social behavior

    Directory of Open Access Journals (Sweden)

    Claudia E Feierstein

    2012-11-01

    Full Text Available In the adult brain, new neurons are added to two brain areas: the olfactory bulb and the hippocampus. Newly-generated neurons integrate into the preexisting circuits, bringing a set of unique properties, such as increased plasticity and responsiveness to stimuli. However, the functional implications of the constant addition of these neurons remain unclear, although they are believed to be important for learning and memory. The levels of neurogenesis are regulated by a variety of environmental factors, as well as during learning, suggesting that new neurons could be important for coping with changing environmental demands. Notably, neurogenesis has been shown to be physiologically regulated in relation to reproductive behavior: neurogenesis increases in female mice upon exposure to cues of the mating partners, during pregnancy and lactation, and in male mice upon exposure to their offspring. In this scenario, and because of the key contribution of olfaction to maternal behavior, we sought to investigate the contribution of adult-generated neurons in the olfactory system to maternal behavior and offspring recognition. To do so, we selectively disrupted neurogenesis in the olfactory pathway of female mice using focal irradiation. Disruption of adult neurogenesis in the olfactory bulb did not affect maternal behavior, or the ability of female mice to discriminate familiar from unfamiliar pups. However, reduction of olfactory neurogenesis resulted in abnormal social interaction of female mice, specifically with male conspecifics. Because the olfactory system is crucial for sex recognition, we suggest that the abnormal interaction with males could result from the inability to detect or discriminate male-specific odors and could therefore have implications for the recognition of potential mating partners. Here, I review the results of this and other studies, and discuss their implications for our understanding of the function of adult neurogenesis.

  6. Olfactory neuroblastoma

    International Nuclear Information System (INIS)

    Rashid, D.; Ahmed, B.; Malik, S.M.; Khan, M.

    2000-01-01

    Olfactory neuroblastoma/esthesioneuroblastoma in a rare malignant tumour of the olfactory neuroepithelium. This is a report of 5 cases managed over the last 10 years at Combined Military Hospital, Rawalpindi. Age of the patients at presentation ranged from 27 to 70 years. The main symptoms were unilateral nasal obstruction and intermittent epistaxis. The mean duration of symptoms at presentation was 11 months. Two patients were staged as B and 3 as C at presentation. The stage of the disease correlated with the duration of symptoms. All the cases were diagnosed on histopathology. Three were offered combination of surgery and radiotherapy. One patient received only surgical treatment and one patient received radiotherapy and chemotherapy. Combination of surgery and radiotherapy showed best results. (author)

  7. Disrupted Olfactory Integration in Schizophrenia: Functional Connectivity Study.

    Science.gov (United States)

    Kiparizoska, Sara; Ikuta, Toshikazu

    2017-09-01

    Evidence for olfactory dysfunction in schizophrenia has been firmly established. However, in the typical understanding of schizophrenia, olfaction is not recognized to contribute to or interact with the illness. Despite the solid presence of olfactory dysfunction in schizophrenia, its relation to the rest of the illness remains largely unclear. Here, we aimed to examine functional connectivity of the olfactory bulb, olfactory tract, and piriform cortices and isolate the network that would account for the altered olfaction in schizophrenia. We examined the functional connectivity of these specific olfactory regions in order to isolate other brain regions associated with olfactory processing in schizophrenia. Using the resting state functional MRI data from the Center for Biomedical Research Excellence in Brain Function and Mental Illness, we compared 84 patients of schizophrenia and 90 individuals without schizophrenia. The schizophrenia group showed disconnectivity between the anterior piriform cortex and the nucleus accumbens, between the posterior piriform cortex and the middle frontal gyrus, and between the olfactory tract and the visual cortices. The current results suggest functional disconnectivity of olfactory regions in schizophrenia, which may account for olfactory dysfunction and disrupted integration with other sensory modalities in schizophrenia. © The Author 2017. Published by Oxford University Press on behalf of CINP.

  8. Cladistic analysis of olfactory and vomeronasal systems.

    Science.gov (United States)

    Ubeda-Bañon, Isabel; Pro-Sistiaga, Palma; Mohedano-Moriano, Alicia; Saiz-Sanchez, Daniel; de la Rosa-Prieto, Carlos; Gutierrez-Castellanos, Nicolás; Lanuza, Enrique; Martinez-Garcia, Fernando; Martinez-Marcos, Alino

    2011-01-01

    Most tetrapods possess two nasal organs for detecting chemicals in their environment, which are the sensory detectors of the olfactory and vomeronasal systems. The seventies' view that the olfactory system was only devoted to sense volatiles, whereas the vomeronasal system was exclusively specialized for pheromone detection was challenged by accumulating data showing deep anatomical and functional interrelationships between both systems. In addition, the assumption that the vomeronasal system appeared as an adaptation to terrestrial life is being questioned as well. The aim of the present work is to use a comparative strategy to gain insight in our understanding of the evolution of chemical "cortex." We have analyzed the organization of the olfactory and vomeronasal cortices of reptiles, marsupials, and placental mammals and we have compared our findings with data from other taxa in order to better understand the evolutionary history of the nasal sensory systems in vertebrates. The olfactory and vomeronsasal cortices have been re-investigated in garter snakes (Thamnophis sirtalis), short-tailed opossums (Monodelphis domestica), and rats (Rattus norvegicus) by tracing the efferents of the main and accessory olfactory bulbs using injections of neuroanatomical anterograde tracers (dextran-amines). In snakes, the medial olfactory tract is quite evident, whereas the main vomeronasal-recipient structure, the nucleus sphaericus is a folded cortical-like structure, located at the caudal edge of the amygdala. In marsupials, which are acallosal mammals, the rhinal fissure is relatively dorsal and the olfactory and vomeronasal cortices relatively expanded. Placental mammals, like marsupials, show partially overlapping olfactory and vomeronasal projections in the rostral basal telencephalon. These data raise the interesting question of how the telencephalon has been re-organized in different groups according to the biological relevance of chemical senses.

  9. PKA Increases in the Olfactory Bulb Act as Unconditioned Stimuli and Provide Evidence for Parallel Memory Systems: Pairing Odor with Increased PKA Creates Intermediate- and Long-Term, but Not Short-Term, Memories

    Science.gov (United States)

    Grimes, Matthew T.; Harley, Carolyn W.; Darby-King, Andrea; McLean, John H.

    2012-01-01

    Neonatal odor-preference memory in rat pups is a well-defined associative mammalian memory model dependent on cAMP. Previous work from this laboratory demonstrates three phases of neonatal odor-preference memory: short-term (translation-independent), intermediate-term (translation-dependent), and long-term (transcription- and…

  10. The jugular bulb diverticulum

    International Nuclear Information System (INIS)

    Wadin, K.; Wilbrand, H.

    1986-01-01

    Two hundred and forty-five temporal bone specimens were examined radiographically. Subsequently the topographic relationship between the jugular fossa and surrounding structures was evaluated in plastic casts of the specimens. Fifty-eight casts showed a high jugular fossa and in 17 a jugular bulb diverticulum was found. A diverticulum is regarded as an anomaly of the high jugular bulb and presumably has a potential for expansion. Most frequently a diverticulum was directed medially into the space between the internal acoustic meatus, the vestibular aqueduct and the posterior cranial fossa. Seven diverticula reached the level of the internal acoustic meatus. Encroachment upon the vestibular aqueduct was seen in 4 casts and both the internal acoustic meatus and the cochlear aqueduct were very close to the diverticulum. A few diverticula were directed postero-laterally close to the facial canal and the stapedius muscle. The investigation was supplemented with a selected clinical material of radiographs of temporal bones with high fossae. The results corresponded to those of the experimental investigation. The jugular bulb diverticulum is a relatively common feature and should be regarded as an anomaly with a potential to give rise to clinical symptoms consequent to its intrusion upon surrounding structures. (orig.)

  11. Olfactory stem cells, a new cellular model for studying molecular mechanisms underlying familial dysautonomia.

    Directory of Open Access Journals (Sweden)

    Nathalie Boone

    Full Text Available BACKGROUND: Familial dysautonomia (FD is a hereditary neuropathy caused by mutations in the IKBKAP gene, the most common of which results in variable tissue-specific mRNA splicing with skipping of exon 20. Defective splicing is especially severe in nervous tissue, leading to incomplete development and progressive degeneration of sensory and autonomic neurons. The specificity of neuron loss in FD is poorly understood due to the lack of an appropriate model system. To better understand and modelize the molecular mechanisms of IKBKAP mRNA splicing, we collected human olfactory ecto-mesenchymal stem cells (hOE-MSC from FD patients. hOE-MSCs have a pluripotent ability to differentiate into various cell lineages, including neurons and glial cells. METHODOLOGY/PRINCIPAL FINDINGS: We confirmed IKBKAP mRNA alternative splicing in FD hOE-MSCs and identified 2 novel spliced isoforms also present in control cells. We observed a significant lower expression of both IKBKAP transcript and IKAP/hELP1 protein in FD cells resulting from the degradation of the transcript isoform skipping exon 20. We localized IKAP/hELP1 in different cell compartments, including the nucleus, which supports multiple roles for that protein. We also investigated cellular pathways altered in FD, at the genome-wide level, and confirmed that cell migration and cytoskeleton reorganization were among the processes altered in FD. Indeed, FD hOE-MSCs exhibit impaired migration compared to control cells. Moreover, we showed that kinetin improved exon 20 inclusion and restores a normal level of IKAP/hELP1 in FD hOE-MSCs. Furthermore, we were able to modify the IKBKAP splicing ratio in FD hOE-MSCs, increasing or reducing the WT (exon 20 inclusion:MU (exon 20 skipping ratio respectively, either by producing free-floating spheres, or by inducing cells into neural differentiation. CONCLUSIONS/SIGNIFICANCE: hOE-MSCs isolated from FD patients represent a new approach for modeling FD to better

  12. Statistical approach in search for optimal signal in simple olfactory neuronal models

    Czech Academy of Sciences Publication Activity Database

    Pokora, Ondřej; Lánský, Petr

    2008-01-01

    Roč. 214, 1-2 (2008), s. 100-108 ISSN 0025-5564 R&D Projects: GA MŠk(CZ) LC554; GA AV ČR(CZ) 1ET400110401 Grant - others:GA MŠk(CZ) LC06024 Institutional research plan: CEZ:AV0Z50110509 Keywords : Fisher information * olfactory neuron Subject RIV: BO - Biophysics Impact factor: 1.148, year: 2008

  13. Kappe neurons, a novel population of olfactory sensory neurons.

    Science.gov (United States)

    Ahuja, Gaurav; Bozorg Nia, Shahrzad; Zapilko, Veronika; Shiriagin, Vladimir; Kowatschew, Daniel; Oka, Yuichiro; Korsching, Sigrun I

    2014-02-10

    Perception of olfactory stimuli is mediated by distinct populations of olfactory sensory neurons, each with a characteristic set of morphological as well as functional parameters. Beyond two large populations of ciliated and microvillous neurons, a third population, crypt neurons, has been identified in teleost and cartilaginous fishes. We report here a novel, fourth olfactory sensory neuron population in zebrafish, which we named kappe neurons for their characteristic shape. Kappe neurons are identified by their Go-like immunoreactivity, and show a distinct spatial distribution within the olfactory epithelium, similar to, but significantly different from that of crypt neurons. Furthermore, kappe neurons project to a single identified target glomerulus within the olfactory bulb, mdg5 of the mediodorsal cluster, whereas crypt neurons are known to project exclusively to the mdg2 glomerulus. Kappe neurons are negative for established markers of ciliated, microvillous and crypt neurons, but appear to have microvilli. Kappe neurons constitute the fourth type of olfactory sensory neurons reported in teleost fishes and their existence suggests that encoding of olfactory stimuli may require a higher complexity than hitherto assumed already in the peripheral olfactory system.

  14. A brain slice culture model for studies of endogenous and exogenous precursor cell migration in the rostral migratory stream

    DEFF Research Database (Denmark)

    Tanvig, Mette; Blaabjerg, Morten; Andersen, Rikke K

    2009-01-01

    The rostral migratory stream (RMS) is the main pathway by which newly born subventricular zone (SVZ) cells reach the olfactory bulb (OB) in rodents. This migration has been well studied in vivo, but an organotypic in vitro model would facilitate more experimental investigations. Here we introduce...

  15. Projections from the posterolateral olfactory amygdala to the ventral striatum: neural basis for reinforcing properties of chemical stimuli

    Directory of Open Access Journals (Sweden)

    Lanuza Enrique

    2007-11-01

    Full Text Available Abstract Background Vertebrates sense chemical stimuli through the olfactory receptor neurons whose axons project to the main olfactory bulb. The main projections of the olfactory bulb are directed to the olfactory cortex and olfactory amygdala (the anterior and posterolateral cortical amygdalae. The posterolateral cortical amygdaloid nucleus mainly projects to other amygdaloid nuclei; other seemingly minor outputs are directed to the ventral striatum, in particular to the olfactory tubercle and the islands of Calleja. Results Although the olfactory projections have been previously described in the literature, injection of dextran-amines into the rat main olfactory bulb was performed with the aim of delimiting the olfactory tubercle and posterolateral cortical amygdaloid nucleus in our own material. Injection of dextran-amines into the posterolateral cortical amygdaloid nucleus of rats resulted in anterograde labeling in the ventral striatum, in particular in the core of the nucleus accumbens, and in the medial olfactory tubercle including some islands of Calleja and the cell bridges across the ventral pallidum. Injections of Fluoro-Gold into the ventral striatum were performed to allow retrograde confirmation of these projections. Conclusion The present results extend previous descriptions of the posterolateral cortical amygdaloid nucleus efferent projections, which are mainly directed to the core of the nucleus accumbens and the medial olfactory tubercle. Our data indicate that the projection to the core of the nucleus accumbens arises from layer III; the projection to the olfactory tubercle arises from layer II and is much more robust than previously thought. This latter projection is directed to the medial olfactory tubercle including the corresponding islands of Calleja, an area recently described as critical node for the neural circuit of addiction to some stimulant drugs of abuse.

  16. Expression of calmodulin mRNA in rat olfactory neuroepithelium.

    Science.gov (United States)

    Biffo, S; Goren, T; Khew-Goodall, Y S; Miara, J; Margolis, F L

    1991-04-01

    A calmodulin (CaM) cDNA was isolated by differential hybridization screening of a lambda gt10 library prepared from rat olfactory mucosa. This cDNA fragment, containing most of the open reading frame of the rat CaMI gene, was subcloned and used to characterize steady-state expression of CaM mRNA in rat olfactory neuroepithelium and bulb. Within the bulb mitral cells are the primary neuronal population expressing CaM mRNA. The major CaM mRNA expressed in the olfactory mucosa is 1.7 kb with smaller contributions from mRNAs of 4.0 and 1.4 kb. CaM mRNA was primarily associated with the olfactory neurons and, despite the cellular complexity of the tissue and the known involvement of CaM in diverse cellular processes, was only minimally evident in sustentacular cells, gland cells or respiratory epithelium. Following bulbectomy CaM mRNA declines in the olfactory neuroepithelium as does olfactory marker protein (OMP) mRNA. In contrast to the latter, CaM mRNA makes a partial recovery by one month after surgery. These results, coupled with those from in situ hybridization, indicate that CaM mRNA is expressed in both mature and immature olfactory neurons. The program regulating CaM gene expression in olfactory neurons is distinct from those controlling expression of B50/GAP43 in immature, or OMP in mature, neurons respectively.

  17. Peripheral-type benzodiazepine receptors in the central nervous system: localization to olfactory nerves.

    Science.gov (United States)

    Anholt, R R; Murphy, K M; Mack, G E; Snyder, S H

    1984-02-01

    Binding levels of [3H]Ro5-4864, a ligand selective for peripheral-type benzodiazepine receptors, are substantially higher in homogenates of the olfactory bulb than in the rest of the brain. Among peripheral tissues evaluated, high levels of [3H]Ro5-4864 binding are found in the nasal epithelium. Drug displacement studies show that these binding sites are pharmacologically of the peripheral type. Their presence in the nasal epithelium and in the olfactory bulb can be demonstrated in several different mammalian species. Autoradiographic studies of murine nose reveal a bipolar staining pattern around the cell bodies of the olfactory receptor cells, suggesting the presence of peripheral-type benzodiazepine receptors on both processes of these bipolar neurons. In the brain a high density of [3H]Ro5-4864 binding sites occurs in the nerve fiber and glomerular layers of the olfactory bulb. Throughout the rest of the brain [3H]Ro5-4864-associated silver grains are diffusely distributed with intense staining over the choroid plexus and along the ependymal linings of the ventricles. Both the distribution and the ontogenic development of the peripheral-type benzodiazepine receptors differ from the central-type receptors. Intranasal irrigation with 5% ZnSO4 results in a 50% reduction of peripheral-type benzodiazepine receptors in the olfactory bulb without affecting the density of central-type benzodiazepine receptors. Thus, [3H]Ro5-4864 binding sites in the olfactory bulb appear in large part to be localized to olfactory nerves which originate in the nasal epithelium.

  18. Functional MRI of the olfactory system in conscious dogs.

    Directory of Open Access Journals (Sweden)

    Hao Jia

    Full Text Available We depend upon the olfactory abilities of dogs for critical tasks such as detecting bombs, landmines, other hazardous chemicals and illicit substances. Hence, a mechanistic understanding of the olfactory system in dogs is of great scientific interest. Previous studies explored this aspect at the cellular and behavior levels; however, the cognitive-level neural substrates linking them have never been explored. This is critical given the fact that behavior is driven by filtered sensory representations in higher order cognitive areas rather than the raw odor maps of the olfactory bulb. Since sedated dogs cannot sniff, we investigated this using functional magnetic resonance imaging of conscious dogs. We addressed the technical challenges of head motion using a two pronged strategy of behavioral training to keep dogs' head as still as possible and a single camera optical head motion tracking system to account for residual jerky movements. We built a custom computer-controlled odorant delivery system which was synchronized with image acquisition, allowing the investigation of brain regions activated by odors. The olfactory bulb and piriform lobes were commonly activated in both awake and anesthetized dogs, while the frontal cortex was activated mainly in conscious dogs. Comparison of responses to low and high odor intensity showed differences in either the strength or spatial extent of activation in the olfactory bulb, piriform lobes, cerebellum, and frontal cortex. Our results demonstrate the viability of the proposed method for functional imaging of the olfactory system in conscious dogs. This could potentially open up a new field of research in detector dog technology.

  19. Properties and mechanisms of olfactory learning and memory

    Directory of Open Access Journals (Sweden)

    Michelle T Tong

    2014-07-01

    Full Text Available Memories are dynamic physical phenomena with psychometric forms as well as characteristic timescales. Most of our understanding of the cellular mechanisms underlying the neurophysiology of memory, however, derives from one-trial learning paradigms that, while powerful, do not fully embody the gradual, representational, and statistical aspects of cumulative learning. The early olfactory system -- particularly olfactory bulb -- comprises a reasonably well-understood and experimentally accessible neuronal network with intrinsic plasticity that underlies both one-trial (adult aversive, neonatal and cumulative (adult appetitive odor learning. These olfactory circuits employ many of the same molecular and structural mechanisms of memory as, for example, hippocampal circuits following inhibitory avoidance conditioning, but the temporal sequences of post-conditioning molecular events are likely to differ owing to the need to incorporate new information from ongoing learning events into the evolving memory trace. Moreover, the shapes of acquired odor representations, and their gradual transformation over the course of cumulative learning, also can be directly measured, adding an additional representational dimension to the traditional metrics of memory strength and persistence. In this review, we describe some established molecular and structural mechanisms of memory with a focus on the timecourses of post-conditioning molecular processes. We describe the properties of odor learning intrinsic to the olfactory bulb and review the utility of the olfactory system of adult rodents as a memory system in which to study the cellular mechanisms of cumulative learning.

  20. Extrabulbar olfactory system and nervus terminalis FMRFamide immunoreactive components in Xenopus laevis ontogenesis.

    Science.gov (United States)

    Pinelli, Claudia; D'Aniello, Biagio; Polese, Gianluca; Rastogi, Rakesh K

    2004-09-01

    The extrabulbar olfactory system (EBOS) is a collection of nerve fibers which originate from primary olfactory receptor-like neurons and penetrate into the brain bypassing the olfactory bulbs. Our description is based upon the application of two neuronal tracers (biocytin, carbocyanine DiI) in the olfactory sac, at the cut end of the olfactory nerve and in the telencephalon of the developing clawed frog. The extrabulbar olfactory system was observed already at stage 45, which is the first developmental stage compatible with our techniques; at this stage, the extrabulbar olfactory system fibers terminated diffusely in the preoptic area. A little later in development, i.e. at stage 50, the extrabulbar olfactory system was maximally developed, extending as far caudally as the rhombencephalon. In the metamorphosing specimens, the extrabulbar olfactory system appeared reduced in extension; caudally, the fiber terminals did not extend beyond the diencephalon. While a substantial overlapping of biocytin/FMRFamide immunoreactivity was observed along the olfactory pathways as well as in the telencephalon, FMRFamide immunoreactivity was never observed to be colocalized in the same cellular or fiber components visualized by tracer molecules. The question whether the extrabulbar olfactory system and the nervus terminalis (NT) are separate anatomical entities or represent an integrated system is discussed.

  1. Neurorestorative clinical application standards for the culture and quality control of olfactory ensheathing cells

    Directory of Open Access Journals (Sweden)

    Xiao J

    2017-09-01

    Full Text Available Juan Xiao,1,2 Lin Chen,3 Gengsheng Mao,1 Wenyong Gao,1,2 Ming Lu,4 Xijing He,5 Hongyun Huang1,2 On behalf of the Neurorestoratology Professional Committee of Chinese Medical Doctors Association (Chinese Association of Neurorestoratology 1Institute of Neurorestoratology, The General Hospital of Chinese People’s Armed Police Forces, Beijing, People’s Republic of China; 2Cell Therapy Center, Beijing Hongtianji Neuroscience Academy, Beijing, People’s Republic of China; 3Department of Neurosurgery, Tsinghua University Yuquan Hospital, Beijing, People’s Republic of China; 4Department of Neurosurgery, 163 Hospital of PLA (Second Affiliated Hospital of Hunan Normal University, Changsha, Hunan Province, People’s Republic of China; 5Department of Orthopedics, Second Affiliated Hospital of Xi’an Jiaotong University, Xian, Shanxi Provine, People’s Republic of China Abstract: Olfactory ensheathing cells (OECs are a novel type of glial cell that can perform and promote many neurorestorative processes in vivo after transplant. To date, dozens of preclinical and clinical studies have confirmed that OECs have unique restoring effects in animal models and human subjects with neurological degeneration or damage, such as spinal cord injury, stroke, cerebral palsy, traumatic brain injury, and motor neuron disease (amyotrophic lateral sclerosis. To ensure the safety and effectiveness of clinical applications utilizing this type of cell, it is important to standardize cell-culture and quality-control processes. Based on a comprehensive review of published clinical studies, as well as existing methods of OEC culture and quality control currently utilized by hospitals and biomedical enterprises, the Chinese Association of Neurorestoratology has developed a set of standards for the culture and quality control of olfactory ensheathing cells for use in clinical applications. These guidelines include standardized training and management procedures for

  2. Therapeutic strategies in an animal model of neurodegeneration

    NARCIS (Netherlands)

    Borre, Y.E.

    2013-01-01

    Neurodegenerative diseases have complex and multifactorial etiologies, creating an enormous burden on society without an effective treatment. This thesis utilized olfactory bulbectomized rats to investigate therapeutic approaches to neurodegenerative disorders. Removal of the olfactory bulbs, leads

  3. Olfactory Neuroblastoma: Diagnostic Difficulty

    Directory of Open Access Journals (Sweden)

    Vidya MN,

    2011-01-01

    Full Text Available Olfactory neuroblastoma is an uncommon malignant tumor of sinonasal tract arising from the olfactory neuro epithelium. The olfactory neuroblastomas presenting with divergent histomorphologies like, epithelial appearance of cells, lacking a neuro fibrillary background and absence of rosettes are difficult to diagnose. Such cases require immunohistochemistry to establish the diagnosis. We describe the clinical features, pathological and immunohistochemical findings of grade IV Olfactory neuroblastoma in a 57 year old man

  4. Odorant responses of olfactory sensory neurons expressing the odorant receptor MOR23: A patch clamp analysis in gene-targeted mice

    OpenAIRE

    Grosmaitre, Xavier; Vassalli, Anne; Mombaerts, Peter; Shepherd, Gordon M.; Ma, Minghong

    2006-01-01

    A glomerulus in the mammalian olfactory bulb receives axonal inputs from olfactory sensory neurons (OSNs) that express the same odorant receptor (OR). Glomeruli are generally thought to represent functional units of olfactory coding, but there are no data on the electrophysiological properties of OSNs that express the same endogenous OR. Here, using patch clamp recordings in an intact epithelial preparation, we directly measured the transduction currents and receptor potentials from the dendr...

  5. Radiosensitivity of garlic air bulbs

    International Nuclear Information System (INIS)

    Zhila, Eh.D.

    1975-01-01

    The paper presents data on the radiosensitivity of various sorts of garlic. It is shown that the frequency of chromosomal aberrations in the irradiated aerial bulbs of stemmed varieties of garlic is directly dependent upon the gmma-ray dose. With increasing dose the germination capacity and the viability of the plants diminishes. A dose of 750 r was found to be critical for the bulbs of the garlic varieties studied

  6. Gender-typical olfactory regulation of sexual behavior in goldfish

    Directory of Open Access Journals (Sweden)

    Makito eKobayashi

    2014-04-01

    Full Text Available It is known that olfaction is essential for the occurrence of sexual behavior in male goldfish. Sex pheromones from ovulatory females elicit male sexual behavior, chasing and sperm releasing act. In female goldfish, ovarian prostaglandin F2α (PGF elicits female sexual behavior, egg releasing act. It has been considered that olfaction does not affect sexual behavior in female goldfish. In the present study, we reexamined the involvement of olfaction in sexual behavior of female goldfish. Olfaction was blocked in male and female goldfish by two methods: nasal occlusion (NO which blocks the reception of olfactants, and olfactory tract section (OTX which blocks transmission of olfactory information from the olfactory bulb to the telencephalon. Sexual behavior of goldfish was induced by administration of PGF to females, an established method for inducing goldfish sexual behavior in both sexes. Sexual behavior in males was suppressed by NO and OTX as previously reported because of lack of pheromone stimulation. In females, NO suppressed sexual behavior but OTX did not affect the occurrence of sexual behavior. Females treated with both NO and OTX performed sexual behavior normally. These results indicate that olfaction is essential in female goldfish to perform sexual behavior as in males but in a different manner. The lack of olfaction in males causes lack of pheromonal stimulation, resulting in no behavior elicited. Whereas the results of female experiments suggest that lack of olfaction in females causes strong inhibition of sexual behavior mediated by the olfactory pathway. Olfactory tract section is considered to block the pathway and remove this inhibition, resulting in the resumption of the behavior. By subtract sectioning of the olfactory tract, it was found that this inhibition was mediated by the medial olfactory tracts, not the lateral olfactory tracts. Thus, it is concluded that goldfish has gender-typical olfactory regulation for sexual

  7. Olfactory learning without the mushroom bodies: Spiking neural network models of the honeybee lateral antennal lobe tract reveal its capacities in odour memory tasks of varied complexities.

    Science.gov (United States)

    MaBouDi, HaDi; Shimazaki, Hideaki; Giurfa, Martin; Chittka, Lars

    2017-06-01

    The honeybee olfactory system is a well-established model for understanding functional mechanisms of learning and memory. Olfactory stimuli are first processed in the antennal lobe, and then transferred to the mushroom body and lateral horn through dual pathways termed medial and lateral antennal lobe tracts (m-ALT and l-ALT). Recent studies reported that honeybees can perform elemental learning by associating an odour with a reward signal even after lesions in m-ALT or blocking the mushroom bodies. To test the hypothesis that the lateral pathway (l-ALT) is sufficient for elemental learning, we modelled local computation within glomeruli in antennal lobes with axons of projection neurons connecting to a decision neuron (LHN) in the lateral horn. We show that inhibitory spike-timing dependent plasticity (modelling non-associative plasticity by exposure to different stimuli) in the synapses from local neurons to projection neurons decorrelates the projection neurons' outputs. The strength of the decorrelations is regulated by global inhibitory feedback within antennal lobes to the projection neurons. By additionally modelling octopaminergic modification of synaptic plasticity among local neurons in the antennal lobes and projection neurons to LHN connections, the model can discriminate and generalize olfactory stimuli. Although positive patterning can be accounted for by the l-ALT model, negative patterning requires further processing and mushroom body circuits. Thus, our model explains several-but not all-types of associative olfactory learning and generalization by a few neural layers of odour processing in the l-ALT. As an outcome of the combination between non-associative and associative learning, the modelling approach allows us to link changes in structural organization of honeybees' antennal lobes with their behavioural performances over the course of their life.

  8. Olfactory Dysfunction as an Early Biomarker in Parkinson's Disease

    Institute of Scientific and Technical Information of China (English)

    Michelle E.Fullard; James F.Morley; John E.Duda

    2017-01-01

    Olfactory dysfunction is common in Parkinson's disease (PD) and often predates the diagnosis by years,reflecting early deposition of Lewy pathology,the histologic hallmark of PD,in the olfactory bulb.Clinical tests are available that allow for the rapid characterization of olfactory dysfunction,including tests of odor identification,discrimination,detection,and recognition thresholds,memory,and tests assessing the build-up of odor intensity across increasing suprathreshold stimulus concentrations.The high prevalence of olfactory impairment,along with the ease and low cost of assessment,has fostered great interest in olfaction as a potential biomarker for PD.Hyposmia may help differentiate PD from other causes of parkinsonism,and may also aid in the identification of "pre-motor" PD due to the early pathologic involvement of olfactory pathways.Olfactory function is also correlated with other non-motor features of PD and may serve as a predictor of cognitive decline.In this article,we summarize the existing literature on olfaction in PD,focusing on the potential for olfaction as a biomarker for early or differential diagnosis and prognosis.

  9. OBscure but not OBsolete: Perturbations of the frontal cortex in common between rodent olfactory bulbectomy model and major depression.

    Science.gov (United States)

    Rajkumar, Ramamoorthy; Dawe, Gavin S

    2018-04-07

    Olfactory bulbectomy (OBX) has been used as a model of depression over several decades. This model presupposes a mechanism that is still not proven in clinical depression. A wealth of clinical literature has focused on the derangements in frontal cortex (prefrontal, orbitofrontal and anterior cingulate cortices) associated with depression. In this comprehensive review, anatomical, electrophysiological and molecular sequelae of bulbectomy in the rodent frontal cortex are explored and compared with findings on brains of humans with major depression. Certain commonalities in neurobiological features of the perturbed frontal cortex in the bulbectomised rodent and the depressed human brain are evident. Also, meta-analysis reports on clinical studies on depressed patients provide prima facie evidence that perturbations in the frontal cortex are associated with major depression. Analysing the pattern of perturbations in the chemical neuroanatomy of the frontal cortex will contribute to understanding of the neurobiology of depression. Revisiting the OBX model of depression to examine these neurobiological changes in frontal cortex with contemporary imaging, proteomics, lipidomics, metabolomics and epigenomics technologies is proposed as an approach to enhance the translational value of this animal model to facilitate identification of targets and biomarkers for clinical depression. Copyright © 2018 Elsevier B.V. All rights reserved.

  10. Associative cortex features in the first olfactory brain relay station.

    Science.gov (United States)

    Doucette, Wilder; Gire, David H; Whitesell, Jennifer; Carmean, Vanessa; Lucero, Mary T; Restrepo, Diego

    2011-03-24

    Synchronized firing of mitral cells (MCs) in the olfactory bulb (OB) has been hypothesized to help bind information together in olfactory cortex (OC). In this survey of synchronized firing by suspected MCs in awake, behaving vertebrates, we find the surprising result that synchronized firing conveys information on odor value ("Is it rewarded?") rather than odor identity ("What is the odor?"). We observed that as mice learned to discriminate between odors, synchronous firing responses to the rewarded and unrewarded odors became divergent. Furthermore, adrenergic blockage decreases the magnitude of odor divergence of synchronous trains, suggesting that MCs contribute to decision-making through adrenergic-modulated synchronized firing. Thus, in the olfactory system information on stimulus reward is found in MCs one synapse away from the sensory neuron. Copyright © 2011 Elsevier Inc. All rights reserved.

  11. The olfactory tubercle encodes odor valence in behaving mice.

    Science.gov (United States)

    Gadziola, Marie A; Tylicki, Kate A; Christian, Diana L; Wesson, Daniel W

    2015-03-18

    Sensory information acquires meaning to adaptively guide behaviors. Despite odors mediating a number of vital behaviors, the components of the olfactory system responsible for assigning meaning to odors remain unclear. The olfactory tubercle (OT), a ventral striatum structure that receives monosynaptic input from the olfactory bulb, is uniquely positioned to transform odor information into behaviorally relevant neural codes. No information is available, however, on the coding of odors among OT neurons in behaving animals. In recordings from mice engaged in an odor discrimination task, we report that the firing rate of OT neurons robustly and flexibly encodes the valence of conditioned odors over identity, with rewarded odors evoking greater firing rates. This coding of rewarded odors occurs before behavioral decisions and represents subsequent behavioral responses. We predict that the OT is an essential region whereby odor valence is encoded in the mammalian brain to guide goal-directed behaviors. Copyright © 2015 the authors 0270-6474/15/354515-13$15.00/0.

  12. Apolipoprotein E4 causes early olfactory network abnormalities and short-term olfactory memory impairments.

    Science.gov (United States)

    Peng, Katherine Y; Mathews, Paul M; Levy, Efrat; Wilson, Donald A

    2017-02-20

    While apolipoprotein (Apo) E4 is linked to increased incidence of Alzheimer's disease (AD), there is growing evidence that it plays a role in functional brain irregularities that are independent of AD pathology. However, ApoE4-driven functional differences within olfactory processing regions have yet to be examined. Utilizing knock-in mice humanized to ApoE4 versus the more common ApoE3, we examined a simple olfactory perceptual memory that relies on the transfer of information from the olfactory bulb (OB) to the piriform cortex (PCX), the primary cortical region involved in higher order olfaction. In addition, we have recorded in vivo resting and odor-evoked local field potentials (LPF) from both brain regions and measured corresponding odor response magnitudes in anesthetized young (6-month-old) and middle-aged (12-month-old) ApoE mice. Young ApoE4 compared to ApoE3 mice exhibited a behavioral olfactory deficit coinciding with hyperactive odor-evoked response magnitudes within the OB that were not observed in older ApoE4 mice. Meanwhile, middle-aged ApoE4 compared to ApoE3 mice exhibited heightened response magnitudes in the PCX without a corresponding olfactory deficit, suggesting a shift with aging in ApoE4-driven effects from OB to PCX. Interestingly, the increased ApoE4-specific response in the PCX at middle-age was primarily due to a dampening of baseline spontaneous activity rather than an increase in evoked response power. Our findings indicate that early ApoE4-driven olfactory memory impairments and OB network abnormalities may be a precursor to later network dysfunction in the PCX, a region that not only is targeted early in AD, but may be selectively vulnerable to ApoE4 genotype. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

  13. [Blockade of the pheromonal effects in rat by central deafferentation of the accessory olfactory system].

    Science.gov (United States)

    Sánchez-Criado, J E

    1979-06-01

    Female rats reared without sex odours from male rats have a five day stral cycle. With exposure to male odour the estral cycle is shortened from five to four days. This pheromonal effect is blocked on deafferenting the vomeronasal system by electrolytically damaging both accessory olfactory bulbs.

  14. Learning-dependent and -independent enhancement of mitral/tufted cell glomerular odor responses following olfactory fear conditioning in awake mice.

    Science.gov (United States)

    Ross, Jordan M; Fletcher, Max L

    2018-04-18

    Associative fear learning produces fear toward the conditioned stimulus (CS) and often generalization, the expansion of fear from the CS to similar, unlearned stimuli. However, how fear learning affects early sensory processing of learned and unlearned stimuli in relation to behavioral fear responses to these stimuli remains unclear. We subjected male and female mice expressing the fluorescent calcium indicator GCaMP3 in olfactory bulb mitral and tufted cells to a classical olfactory fear conditioning paradigm. We then used awake, in vivo calcium imaging to quantify learning-induced changes in glomerular odor responses, which constitute the first site of olfactory processing in the brain. The results demonstrate that odor-shock pairing non-specifically enhances glomerular odor representations in a learning-dependent manner and increases representational similarity between the CS and non-conditioned odors, potentially priming the system towards generalization of learned fear. Additionally, CS-specific glomerular enhancements remain even when associative learning is blocked, suggesting two separate mechanisms lead to enhanced glomerular responses following odor-shock pairings. SIGNIFICANCE STATEMENT In the olfactory bulb (OB), odors are uniquely coded in a spatial map that represents odor identity, making the OB a unique model system for investigating how learned fear alters sensory processing. Classical fear conditioning causes fear of the conditioned stimulus (CS) and of neutral stimuli, known as generalization. Combining fear conditioning with fluorescent calcium imaging of OB glomeruli, we found enhanced glomerular responses of the CS as well as neutral stimuli in awake mice, which mirrors fear generalization. We report that CS and neutral stimuli enhancements are, respectively, learning- independent and learning-dependent. Together, these results reveal distinct mechanisms leading to enhanced OB processing of fear-inducing stimuli and provide important

  15. Could Cells from Your Nose Fix Your Heart? Transplantation of Olfactory Stem Cells in a Rat Model of Cardiac Infarction

    Directory of Open Access Journals (Sweden)

    Cameron McDonald

    2010-01-01

    Full Text Available This study examines the hypothesis that multipotent olfactory mucosal stem cells could provide a basis for the development of autologous cell transplant therapy for the treatment of heart attack. In humans, these cells are easily obtained by simple biopsy. Neural stem cells from the olfactory mucosa are multipotent, with the capacity to differentiate into developmental fates other than neurons and glia, with evidence of cardiomyocyte differentiation in vitro and after transplantation into the chick embryo. Olfactory stem cells were grown from rat olfactory mucosa. These cells are propagated as neurosphere cultures, similar to other neural stem cells. Olfactory neurospheres were grown in vitro, dissociated into single cell suspensions, and transplanted into the infarcted hearts of congeneic rats. Transplanted cells were genetically engineered to express green fluorescent protein (GFP in order to allow them to be identified after transplantation. Functional assessment was attempted using echocardiography in three groups of rats: control, unoperated; infarct only; infarcted and transplanted. Transplantation of neurosphere-derived cells from adult rat olfactory mucosa appeared to restore heart rate with other trends towards improvement in other measures of ventricular function indicated. Importantly, donor-derived cells engrafted in the transplanted cardiac ventricle and expressed cardiac contractile proteins.

  16. Antidepressant-like effects of the aqueous macerate of the bulb of Gladiolus dalenii Van Geel (Iridaceae) in a rat model of epilepsy-associated depression.

    Science.gov (United States)

    Ngoupaye, Gwladys Temkou; Bum, Elisabeth Ngo; Daniels, Willie Mark Uren

    2013-10-20

    In Cameroonian traditional medicine various extracts of Gladiolus dalenii Van Geel (Iridaceae) have been used as a cure for various ailments that include headaches, digestive problems, muscle and joint aches, and some central nervous system disorders such as epilepsy, schizophrenia and mood disorders. Owning to this background, the aim of the study was to investigate whether an aqueous macerate of the bulb of Gladiolus dalenii has any antidepressant activity focusing specifically on depression-like behaviours associated with epilepsy. We used the combined administration of atropine and pilocarpine to rats as our animal model of epilepsy. The forced swim test and spontaneous locomotor activity in the open field test were the two tools used to assess the presence of depression-like behaviour in epileptic and control animals. The following depression-related parameters were determined: plasma ACTH, plasma corticosterone, adrenal gland weight and hippocampal levels of brain-derived neurotrophic factor (BDNF). The effects of Gladiolus dalenii were compared to that of fluoxetine. Our results showed that we had a valid animal model of epilepsy-induced depression as all 3 measures of construct, predictive and face validity were satisfied. The data indicated that Gladiolus dalenii significantly reduced the immobility times in the forced swim test and the locomotor activity as assessed in the open field. A similar pattern was observed when the HPA axis parameters were analysed. Gladiolus dalenii significantly reduced the levels of ACTH, corticosterone, but not the adrenal gland weight. Gladiolus dalenii significantly increased the level of BDNF in the hippocampus. In all parameters measured the effects of Gladiolus dalenii were significantly greater than those of fluoxetine. The results show that Gladiolus dalenii has antidepressant-like properties similar to those of fluoxetine in epilepsy-associated depressive states. The antidepressant activity of Gladiolus dalenii is

  17. CD36 is involved in oleic acid detection by the murine olfactory system.

    Directory of Open Access Journals (Sweden)

    Sonja eOberland

    2015-09-01

    Full Text Available Olfactory signals influence food intake in a variety of species. To maximize the chances of finding a source of calories, an animal’s preference for fatty foods and triglycerides already becomes apparent during olfactory food search behavior. However, the molecular identity of both receptors and ligands mediating olfactory-dependent fatty acid recognition are, so far, undescribed. We here describe that a subset of olfactory sensory neurons expresses the fatty acid receptor CD36 and demonstrate a receptor-like localization of CD36 in olfactory cilia by STED microscopy. CD36-positive olfactory neurons share olfaction-specific transduction elements and project to numerous glomeruli in the ventral olfactory bulb. In accordance with the described roles of CD36 as fatty acid receptor or co-receptor in other sensory systems, the number of olfactory neurons responding to oleic acid, a major milk component, in Ca2+ imaging experiments is drastically reduced in young CD36 knock-out mice. Strikingly, we also observe marked age-dependent changes in CD36 localization, which is prominently present in the ciliary compartment only during the suckling period. Our results support the involvement of CD36 in fatty acid detection by the mammalian olfactory system.

  18. Beta and gamma oscillatory activities associated with olfactory memory tasks: different rhythms for different functional networks?

    Science.gov (United States)

    Martin, Claire; Ravel, Nadine

    2014-01-01

    Olfactory processing in behaving animals, even at early stages, is inextricable from top down influences associated with odor perception. The anatomy of the olfactory network (olfactory bulb, piriform, and entorhinal cortices) and its unique direct access to the limbic system makes it particularly attractive to study how sensory processing could be modulated by learning and memory. Moreover, olfactory structures have been early reported to exhibit oscillatory population activities easy to capture through local field potential recordings. An attractive hypothesis is that neuronal oscillations would serve to "bind" distant structures to reach a unified and coherent perception. In relation to this hypothesis, we will assess the functional relevance of different types of oscillatory activity observed in the olfactory system of behaving animals. This review will focus primarily on two types of oscillatory activities: beta (15-40 Hz) and gamma (60-100 Hz). While gamma oscillations are dominant in the olfactory system in the absence of odorant, both beta and gamma rhythms have been reported to be modulated depending on the nature of the olfactory task. Studies from the authors of the present review and other groups brought evidence for a link between these oscillations and behavioral changes induced by olfactory learning. However, differences in studies led to divergent interpretations concerning the respective role of these oscillations in olfactory processing. Based on a critical reexamination of those data, we propose hypotheses on the functional involvement of beta and gamma oscillations for odor perception and memory.

  19. Beta and gamma oscillatory activities associated with olfactory memory tasks: Different rhythms for different functional networks?

    Directory of Open Access Journals (Sweden)

    Claire eMartin

    2014-06-01

    Full Text Available Olfactory processing in behaving animals, even at early stages, is inextricable from top down influences associated with odor perception. The anatomy of the olfactory network (olfactory bulb, piriform and entorhinal cortices and its unique direct access to the limbic system makes it particularly attractive to study how sensory processing could be modulated by learning and memory. Moreover, olfactory structures have been early reported to exhibit oscillatory population activities easy to capture through local field potential recordings. An attractive hypothesis is that neuronal oscillations would serve to ‘bind’ distant structures to reach a unified and coherent perception. In relation to this hypothesis, we will assess the functional relevance of different types of oscillatory activity observed in the olfactory system of behaving animals. This review will focus primarily on two types of oscillatory activities: beta (15-40 Hz and gamma (60-100 Hz. While gamma oscillations are dominant in the olfactory system in the absence of odorant, both beta and gamma rhythms have been reported to be modulated depending on the nature of the olfactory task. Studies from the authors of the present review and other groups brought evidence for a link between these oscillations and behavioral changes induced by olfactory learning. However, differences in studies led to divergent interpretations concerning the respective role of these oscillations in olfactory processing. Based on a critical reexamination of those data, we propose hypotheses on the functional involvement of beta and gamma oscillations for odor perception and memory.

  20. Unique in vivo properties of olfactory ensheathing cells that may contribute to neural repair and protection following spinal cord injury

    Science.gov (United States)

    Kocsis, Jeffery D.; Lankford, Karen L.; Sasaki, Masanori; Radtke, Christine

    2009-01-01

    Olfactory ensheathing cells (OECs) are specialized glial cells that guide olfactory receptor axons from the nasal mucosa into the brain where they make synaptic contacts in the olfactory bulb. While a number of studies have demonstrated that in vivo transplantation of OECs into injured spinal cord results in improved functional outcome, precise cellular mechanisms underlying this improvement are not fully understood. Current thinking is that OECs can encourage axonal regeneration, provide trophic support for injured neurons and for angiogenesis, and remyelinate axons. However, Schwann cell (SC) transplantation also results in significant functional improvement in animal models of spinal cord injury. In culture SCs and OECs share a number of phenotypic properties such as expression of the low affinity NGF receptor (p75). An important area of research has been to distinguish potential differences in the in vivo behavior of OECs and SCs to determine if one cell type may offer greater advantage as a cellular therapeutic candidate. In this review we focus on several unique features of OECs when they are transplanted into the spinal cord. PMID:19429149

  1. Botrytis species on bulb crops

    NARCIS (Netherlands)

    Lorbeer, J.W.; Seyb, A.M.; Boer, de M.; Ende, van den J.E.

    2007-01-01

    Abstract. A number of Botrytis species are pathogens of bulb crops. Botrytis squamosa (teleomorph=Botrytotinia squamosa) causal agent of botrytis leaf blight and B. allii the causal agent of botrytis neck rotare two of the most important fungal diseases of onion. The taxonomics of several of the

  2. Modeling the cellular mechanisms and olfactory input underlying the triphasic response of moth pheromone-sensitive projection neurons.

    Directory of Open Access Journals (Sweden)

    Yuqiao Gu

    Full Text Available In the antennal lobe of the noctuid moth Agrotis ipsilon, most pheromone-sensitive projection neurons (PNs exhibit a triphasic firing pattern of excitation (E1-inhibition (I-excitation (E2 in response to a pulse of the sex pheromone. To understand the mechanisms underlying this stereotypical discharge, we developed a biophysical model of a PN receiving inputs from olfactory receptor neurons (ORNs via nicotinic cholinergic synapses. The ORN is modeled as an inhomogeneous Poisson process whose firing rate is a function of time and is fitted to extracellular data recorded in response to pheromone stimulations at various concentrations and durations. The PN model is based on the Hodgkin-Huxley formalism with realistic ionic currents whose parameters were derived from previous studies. Simulations revealed that the inhibitory phase I can be produced by a SK current (Ca2+-gated small conductance K+ current and that the excitatory phase E2 can result from the long-lasting response of the ORNs. Parameter analysis further revealed that the ending time of E1 depends on some parameters of SK, Ca2+, nACh and Na+ currents; I duration mainly depends on the time constant of intracellular Ca2+ dynamics, conductance of Ca2+ currents and some parameters of nACh currents; The mean firing frequency of E1 and E2 depends differentially on the interaction of various currents. Thus it is likely that the interplay between PN intrinsic currents and feedforward synaptic currents are sufficient to generate the triphasic firing patterns observed in the noctuid moth A. ipsilon.

  3. Morphological study on the olfactory systems of the snapping turtle, Chelydra serpentina.

    Science.gov (United States)

    Nakamuta, Nobuaki; Nakamuta, Shoko; Kato, Hideaki; Yamamoto, Yoshio

    2016-06-01

    In this study, the olfactory system of a semi-aquatic turtle, the snapping turtle, has been morphologically investigated by electron microscopy, immunohistochemistry, and lectin histochemistry. The nasal cavity of snapping turtle was divided into the upper and lower chambers, lined by the sensory epithelium containing ciliated and non-ciliated olfactory receptor neurons, respectively. Each neuron expressed both Gαolf, the α-subunit of G-proteins coupling to the odorant receptors, and Gαo, the α-subunit of G-proteins coupling to the type 2 vomeronasal receptors. The axons originating from the upper chamber epithelium projected to the ventral part of the olfactory bulb, while those from the lower chamber epithelium to the dorsal part of the olfactory bulb. Despite the identical expression of G-protein α-subunits in the olfactory receptor neurons, these two projections were clearly distinguished from each other by the differential expression of glycoconjugates. In conclusion, these data indicate the presence of two types of olfactory systems in the snapping turtle. Topographic arrangement of the upper and lower chambers and lack of the associated glands in the lower chamber epithelium suggest their possible involvement in the detection of odorants: upper chamber epithelium in the air and the lower chamber epithelium in the water. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Gad67 haploinsufficiency reduces amyloid pathology and rescues olfactory memory deficits in a mouse model of Alzheimer's disease.

    Science.gov (United States)

    Wang, Yue; Wu, Zheng; Bai, Yu-Ting; Wu, Gang-Yi; Chen, Gong

    2017-10-10

    Alzheimer's disease (AD) is the most common age-related neurodegenerative disorder, affecting millions of people worldwide. Although dysfunction of multiple neurotransmitter systems including cholinergic, glutamatergic and GABAergic systems has been associated with AD progression the underlying mechanisms remain elusive. We and others have recently found that GABA content is elevated in AD brains and linked to cognitive deficits in AD mouse models. The glutamic acid decarboxylase 67 (GAD67) is the major enzyme converting glutamate into GABA and has been implied in a number of neurological disorders such as epilepsy and schizophrenia. However, whether Gad67 is involved in AD pathology has not been well studied. Here, we investigate the functional role of GAD67 in an AD mouse model with Gad67 haploinsufficiency that is caused by replacing one allele of Gad67 with green fluorescent protein (GFP) gene during generation of GAD67-GFP mice. To genetically reduce GAD67 in AD mouse brains, we crossed the Gad67 haploinsufficient mice (GAD67-GFP +/- ) with 5xFAD mice (harboring 5 human familial AD mutations in APP and PS1 genes) to generate a new line of bigenic mice. Immunostaining, ELISA, electrophysiology and behavior test were applied to compare the difference between groups. We found that reduction of GAD67 resulted in a significant decrease of amyloid β production in 5xFAD mice. Concurrently, the abnormal astrocytic GABA and tonic GABA currents, as well as the microglial reactivity were significantly reduced in the 5xFAD mice with Gad67 haploinsufficiency. Importantly, the olfactory memory deficit of 5xFAD mice was rescued by Gad67 haploinsufficiency. Our results demonstrate that GAD67 plays an important role in AD pathology, suggesting that GAD67 may be a potential drug target for modulating the progress of AD.

  5. Type 2 diabetes impairs odour detection, olfactory memory and olfactory neuroplasticity; effects partly reversed by the DPP-4 inhibitor Linagliptin.

    Science.gov (United States)

    Lietzau, Grazyna; Davidsson, William; Östenson, Claes-Göran; Chiazza, Fausto; Nathanson, David; Pintana, Hiranya; Skogsberg, Josefin; Klein, Thomas; Nyström, Thomas; Darsalia, Vladimer; Patrone, Cesare

    2018-02-23

    Recent data suggest that olfactory deficits could represent an early marker and a pathogenic mechanism at the basis of cognitive decline in type 2 diabetes (T2D). However, research is needed to further characterize olfactory deficits in diabetes, their relation to cognitive decline and underlying mechanisms.The aim of this study was to determine whether T2D impairs odour detection, olfactory memory as well as neuroplasticity in two major brain areas responsible for olfaction and odour coding: the main olfactory bulb (MOB) and the piriform cortex (PC), respectively. Dipeptidyl peptidase-4 inhibitors (DPP-4i) are clinically used T2D drugs exerting also beneficial effects in the brain. Therefore, we aimed to determine whether DPP-4i could reverse the potentially detrimental effects of T2D on the olfactory system.Non-diabetic Wistar and T2D Goto-Kakizaki rats, untreated or treated for 16 weeks with the DPP-4i linagliptin, were employed. Odour detection and olfactory memory were assessed by using the block, the habituation-dishabituation and the buried pellet tests. We assessed neuroplasticity in the MOB by quantifying adult neurogenesis and GABAergic inhibitory interneurons positive for calbindin, parvalbumin and carletinin. In the PC, neuroplasticity was assessed by quantifying the same populations of interneurons and a newly identified form of olfactory neuroplasticity mediated by post-mitotic doublecortin (DCX) + immature neurons.We show that T2D dramatically reduced odour detection and olfactory memory. Moreover, T2D decreased neurogenesis in the MOB, impaired the differentiation of DCX+ immature neurons in the PC and altered GABAergic interneurons protein expression in both olfactory areas. DPP-4i did not improve odour detection and olfactory memory. However, it normalized T2D-induced effects on neuroplasticity.The results provide new knowledge on the detrimental effects of T2D on the olfactory system. This knowledge could constitute essentials for

  6. A novel neural substrate for the transformation of olfactory inputs into motor output.

    Directory of Open Access Journals (Sweden)

    Dominique Derjean

    2010-12-01

    Full Text Available It is widely recognized that animals respond to odors by generating or modulating specific motor behaviors. These reactions are important for daily activities, reproduction, and survival. In the sea lamprey, mating occurs after ovulated females are attracted to spawning sites by male sex pheromones. The ubiquity and reliability of olfactory-motor behavioral responses in vertebrates suggest tight coupling between the olfactory system and brain areas controlling movements. However, the circuitry and the underlying cellular neural mechanisms remain largely unknown. Using lamprey brain preparations, and electrophysiology, calcium imaging, and tract tracing experiments, we describe the neural substrate responsible for transforming an olfactory input into a locomotor output. We found that olfactory stimulation with naturally occurring odors and pheromones induced large excitatory responses in reticulospinal cells, the command neurons for locomotion. We have also identified the anatomy and physiology of this circuit. The olfactory input was relayed in the medial part of the olfactory bulb, in the posterior tuberculum, in the mesencephalic locomotor region, to finally reach reticulospinal cells in the hindbrain. Activation of this olfactory-motor pathway generated rhythmic ventral root discharges and swimming movements. Our study bridges the gap between behavior and cellular neural mechanisms in vertebrates, identifying a specific subsystem within the CNS, dedicated to producing motor responses to olfactory inputs.

  7. Nested Expression Domains for Odorant Receptors in Zebrafish Olfactory Epithelium

    Science.gov (United States)

    Weth, Franco; Nadler, Walter; Korsching, Sigrun

    1996-11-01

    The mapping of high-dimensional olfactory stimuli onto the two-dimensional surface of the nasal sensory epithelium constitutes the first step in the neuronal encoding of olfactory input. We have used zebrafish as a model system to analyze the spatial distribution of odorant receptor molecules in the olfactory epithelium by quantitative in situ hybridization. To this end, we have cloned 10 very divergent zebrafish odorant receptor molecules by PCR. Individual genes are expressed in sparse olfactory receptor neurons. Analysis of the position of labeled cells in a simplified coordinate system revealed three concentric, albeit overlapping, expression domains for the four odorant receptors analyzed in detail. Such regionalized expression should result in a corresponding segregation of functional response properties. This might represent the first step of spatial encoding of olfactory input or be essential for the development of the olfactory system.

  8. Induction of an Olfactory Memory by the Activation of a Metabotropic Glutamate Receptor

    Science.gov (United States)

    Kaba, Hideto; Hayashi, Yasunori; Higuchi, Takashi; Nakanishi, Shigetada

    1994-07-01

    Female mice form an olfactory memory of male pheromones at mating; exposure to the pheromones of a strange male after that mating will block pregnancy. The formation of this memory is mediated by the accessory olfactory system, in which an increase in norepinephrine after mating reduces inhibitory transmission of γ-aminobutyric acid from the granule cells to the mitral cells. This study shows that the activation of mGluR2, a metabotropic glutamate receptor that suppresses the γ-aminobutyric acid inhibition of the mitral cells, permits the formation of a specific olfactory memory without the occurrence of mating by infusion of mGluR2 agonists into the female's accessory olfactory bulb. This memory faithfully reflects the memory formed at mating.

  9. An olfactory cocktail party: figure-ground segregation of odorants in rodents.

    Science.gov (United States)

    Rokni, Dan; Hemmelder, Vivian; Kapoor, Vikrant; Murthy, Venkatesh N

    2014-09-01

    In odorant-rich environments, animals must be able to detect specific odorants of interest against variable backgrounds. However, studies have found that both humans and rodents are poor at analyzing the components of odorant mixtures, suggesting that olfaction is a synthetic sense in which mixtures are perceived holistically. We found that mice could be easily trained to detect target odorants embedded in unpredictable and variable mixtures. To relate the behavioral performance to neural representation, we imaged the responses of olfactory bulb glomeruli to individual odors in mice expressing the Ca(2+) indicator GCaMP3 in olfactory receptor neurons. The difficulty of segregating the target from the background depended strongly on the extent of overlap between the glomerular responses to target and background odors. Our study indicates that the olfactory system has powerful analytic abilities that are constrained by the limits of combinatorial neural representation of odorants at the level of the olfactory receptors.

  10. Ionotropic crustacean olfactory receptors.

    Directory of Open Access Journals (Sweden)

    Elizabeth A Corey

    Full Text Available The nature of the olfactory receptor in crustaceans, a major group of arthropods, has remained elusive. We report that spiny lobsters, Panulirus argus, express ionotropic receptors (IRs, the insect chemosensory variants of ionotropic glutamate receptors. Unlike insects IRs, which are expressed in a specific subset of olfactory cells, two lobster IR subunits are expressed in most, if not all, lobster olfactory receptor neurons (ORNs, as confirmed by antibody labeling and in situ hybridization. Ligand-specific ORN responses visualized by calcium imaging are consistent with a restricted expression pattern found for other potential subunits, suggesting that cell-specific expression of uncommon IR subunits determines the ligand sensitivity of individual cells. IRs are the only type of olfactory receptor that we have detected in spiny lobster olfactory tissue, suggesting that they likely mediate olfactory signaling. Given long-standing evidence for G protein-mediated signaling in activation of lobster ORNs, this finding raises the interesting specter that IRs act in concert with second messenger-mediated signaling.

  11. Effect of kamikihito (TJ-137) on paclitaxel-induced olfactory neuropathy in vivo

    International Nuclear Information System (INIS)

    Yamamoto, Junpei

    2012-01-01

    A Kampo product, kamikihito (product name code: TJ-137), has ingredients that promote nerve growth. Paclitaxel, a cancer chemotherapeutic agent, is toxic to olfactory nerve cells in vivo. We found that TJ-137 is effective in reducing paclitaxel induced olfactory neuropathy in vivo. Female 7-week-old Bulb/c mice were fed food containing TJ-137, or control food, for 14 days before and after intravenous paclitaxel administration. 201 Tl uptake in nasal turbinates of TJ-137 treated mice (n=8) and control mice (n=9) was assessed by gamma spectrometry 6 hrs after nasal administration of 201 Tl. The epithelial changes in the nasal turbinates of mice were assessed by H and E and immunohistochemical staining for the olfactory marker protein (OMP). The accumulation of the neuronal tracer (Dextran tetramethylrhodamine) in the olfactory bulb was assessed in frozen sections of mice 48 hrs after nasal administration of the tracer. The epithelium of nasal turbinates of TJ-137 treated mice was less injured than that of the control mice after paclitaxel administration. The nasal epithelium was significantly thicker in TJ-137 treated mice compared to control mice (P=0.019). The accumulation of the neuronal tracer in the olfactory bulb was higher in the TJ-137 treated mice compared to controls. 201 Tl uptake per weight in nasal turbinate of TJ-137 treated mice was significantly higher than that of control mice (P=0.008). Pre-medication with TJ-137 (kamikihito) was effective in increasing olfactory nerve viability after paclitaxel administration in vivo. (author)

  12. Functional Reintegration of Sensory Neurons and Transitional Dendritic Reduction of Mitral/Tufted Cells during Injury-Induced Recovery of the Larval Xenopus Olfactory Circuit

    Directory of Open Access Journals (Sweden)

    Sara J. Hawkins

    2017-11-01

    Full Text Available Understanding the mechanisms involved in maintaining lifelong neurogenesis has a clear biological and clinical interest. In the present study, we performed olfactory nerve transection on larval Xenopus to induce severe damage to the olfactory circuitry. We surveyed the timing of the degeneration, subsequent rewiring and functional regeneration of the olfactory system following injury. A range of structural labeling techniques and functional calcium imaging were performed on both tissue slices and whole brain preparations. Cell death of olfactory receptor neurons and proliferation of stem cells in the olfactory epithelium were immediately increased following lesion. New olfactory receptor neurons repopulated the olfactory epithelium and once again showed functional responses to natural odorants within 1 week after transection. Reinnervation of the olfactory bulb (OB by newly formed olfactory receptor neuron axons also began at this time. Additionally, we observed a temporary increase in cell death in the OB and a subsequent loss in OB volume. Mitral/tufted cells, the second order neurons of the olfactory system, largely survived, but transiently lost dendritic tuft complexity. The first odorant-induced responses in the OB were observed 3 weeks after nerve transection and the olfactory network showed signs of major recovery, both structurally and functionally, after 7 weeks.

  13. How to handle and care for bulbs in ophthalmic equipment

    Directory of Open Access Journals (Sweden)

    Ismael Cordero

    2013-08-01

    Full Text Available Many devices used in eye care rely on light bulbs or lamps for their operation. All light bulbs have a limited lifespan and when the bulb fails the device becomes unusable. Therefore, knowing how to handle, how to inspect and how to replace bulbs is important. Just as important is keeping spare bulbs to hand!

  14. Gonadotropin-releasing hormone immunoreactivity in the adult and fetal human olfactory system.

    Science.gov (United States)

    Kim, K H; Patel, L; Tobet, S A; King, J C; Rubin, B S; Stopa, E G

    1999-05-01

    Studies in fetal brain tissue of rodents, nonhuman primates and birds have demonstrated that cells containing gonadotropin-releasing hormone (GnRH) migrate from the olfactory placode across the nasal septum into the forebrain. The purpose of this study was to examine GnRH neurons in components of the adult and fetal human olfactory system. In the adult human brain (n=4), immunoreactive GnRH was evident within diffusely scattered cell bodies and processes in the olfactory bulb, olfactory nerve, olfactory cortex, and nervus terminalis located on the anterior surface of the gyrus rectus. GnRH-immunoreactive structures showed a similar distribution in 20-week human fetal brains (n=2), indicating that the migration of GnRH neurons is complete at this time. In 10-11-week fetal brains (n=2), more cells were noted in the nasal cavity than in the brain. Our data are consistent with observations made in other species, confirming olfactory derivation and migration of GnRH neurons into the brain from the olfactory placode. Copyright 1999 Elsevier Science B.V.

  15. Heterogeneous sensory innervation and extensive intrabulbar connections of olfactory necklace glomeruli.

    Directory of Open Access Journals (Sweden)

    Renee E Cockerham

    Full Text Available The mammalian nose employs several olfactory subsystems to recognize and transduce diverse chemosensory stimuli. These subsystems differ in their anatomical position within the nasal cavity, their targets in the olfactory forebrain, and the transduction mechanisms they employ. Here we report that they can also differ in the strategies they use for stimulus coding. Necklace glomeruli are the sole main olfactory bulb (MOB targets of an olfactory sensory neuron (OSN subpopulation distinguished by its expression of the receptor guanylyl cyclase GC-D and the phosphodiesterase PDE2, and by its chemosensitivity to the natriuretic peptides uroguanylin and guanylin and the gas CO(2. In stark contrast to the homogeneous sensory innervation of canonical MOB glomeruli from OSNs expressing the same odorant receptor (OR, we find that each necklace glomerulus of the mouse receives heterogeneous innervation from at least two distinct sensory neuron populations: one expressing GC-D and PDE2, the other expressing olfactory marker protein. In the main olfactory system it is thought that odor identity is encoded by a combinatorial strategy and represented in the MOB by a pattern of glomerular activation. This combinatorial coding scheme requires functionally homogeneous sensory inputs to individual glomeruli by OSNs expressing the same OR and displaying uniform stimulus selectivity; thus, activity in each glomerulus reflects the stimulation of a single OSN type. The heterogeneous sensory innervation of individual necklace glomeruli by multiple, functionally distinct, OSN subtypes precludes a similar combinatorial coding strategy in this olfactory subsystem.

  16. Refining the dual olfactory hypothesis: pheromone reward and odour experience.

    Science.gov (United States)

    Martínez-García, Fernando; Martínez-Ricós, Joana; Agustín-Pavón, Carmen; Martínez-Hernández, Jose; Novejarque, Amparo; Lanuza, Enrique

    2009-06-25

    In rodents, sexual advertisement and gender recognition are mostly (if not exclusively) mediated by chemosignals. Specifically, there is ample evidence indicating that female mice are 'innately' attracted by male sexual pheromones that have critical non-volatile components and are detected by the vomeronasal organ. These pheromones can only get access to the vomeronasal organ by active pumping mechanisms that require close contact with the source of the stimulus (e.g. urine marks) during chemoinvestigation. We have hypothesised that male sexual pheromones are rewarding to female mice. Indeed, male-soiled bedding can be used as a reinforcer to induce conditioned place preference, provided contact with the bedding is allowed. The neural mechanisms of pheromone reward seem, however, different from those employed by other natural reinforcers, such as the sweetness or postingestive effects of sucrose. In contrast to vomeronasal-detected male sexual pheromones, male-derived olfactory stimuli (volatiles) are not intrinsically attractive to female mice. However, after repeated exposure to male-soiled bedding, intact female mice develop an acquired preference for male odours. On the contrary, in females whose accessory olfactory bulbs have been lesioned, exposure to male-soiled bedding induces aversion to male odorants. These considerations, together with data on the different properties of olfactory and vomeronasal receptors, lead us to make a proposal for the complementary roles that the olfactory and vomeronasal systems play in intersexual attraction and in other forms of intra- or inter-species communication.

  17. Neural circuits containing olfactory neurons are involved in prepulse inhibition of the startle reflex in rats

    Directory of Open Access Journals (Sweden)

    Haichen eNiu

    2015-03-01

    Full Text Available Many neuropsychiatric disorders, such as schizophrenia, have been associated with abnormalities in the function of the olfactory system and prepulse inhibition (PPI of the startle reflex. However, whether these two abnormalities are related is unclear. The present study was designed to determine whether inhibiting olfactory sensory input via the infusion of zinc sulfate (ZnE, 0.17 M, 0.5 ml into the olfactory naris disrupts PPI. Furthermore, lidocaine/MK801 was bilaterally microinjected into the olfactory bulb (OB to examine whether the blockade of olfactory sensory input impairs PPI. To identify the neural projections that connect the olfaction- and PPI-related areas of the CNS, trans-synaptic retrograde tracing using a recombinant pseudorabies virus (PRV was performed. Our results demonstrated that blocking olfactory sensory input altered olfaction-related behavior. At the functional level, we demonstrated that the inhibition of olfactory sensory input impaired PPI of the startle response subsequent to a decrease in c-fos expression in relevant brain regions. Furthermore, the results of a similar and more robust experiment indicated that blocking olfactory sensory input via the microinjection of lidocaine/MK801 into the OB impaired PPI. At the circuit level, based on trans-synaptic retrograde tracing using PRV, we demonstrated that a large portion of the labeled neurons in several regions of the olfactory cortices connected to the pedunculopontine tegmental nucleus (PPTg. Thus, these data suggest that the olfactory system participates in the regulation of PPI and plays a role in the effect of PPI on the startle response in rats.

  18. The main but not the accessory olfactory system is involved in the processing of socially relevant chemosignals in ungulates.

    Directory of Open Access Journals (Sweden)

    Matthieu eKELLER

    2012-09-01

    Full Text Available Ungulates like sheep and goats have, like many other mammalian species, two complementary olfactory systems. The relative role played by these two systems has long been of interest regarding the sensory control of social behavior. The study of ungulate social behavior could represent a complimentary alternative to rodent studies because they live in a more natural environment and their social behaviors depend heavily on olfaction. In addition, the relative size of the main olfactory bulb (in comparison to the accessory olfactory bulb is more developped than in many other lissencephalic species like rodents. In this review, we present data showing a clear involvement of the main olfactory system in two well-characterized social situations under olfactory control in ungulates, namely maternal behavior and offspring recognition at birth and the reactivation of the gonadotropic axis of females exposed to males during the anestrous season. In conclusion, we discuss the apparent discrepancy between the absence of evidence for a role of the vomeronasal system in ungulate social behavior and the existence of a developed accessory olfactory system in these species.

  19. Olfactory circuits and behaviors of nematodes.

    Science.gov (United States)

    Rengarajan, Sophie; Hallem, Elissa A

    2016-12-01

    Over one billion people worldwide are infected with parasitic nematodes. Many parasitic nematodes actively search for hosts to infect using volatile chemical cues, so understanding the olfactory signals that drive host seeking may elucidate new pathways for preventing infections. The free-living nematode Caenorhabditis elegans is a powerful model for parasitic nematodes: because sensory neuroanatomy is conserved across nematode species, an understanding of the microcircuits that mediate olfaction in C. elegans may inform studies of olfaction in parasitic nematodes. Here we review circuit mechanisms that allow C. elegans to respond to odorants, gases, and pheromones. We also highlight work on the olfactory behaviors of parasitic nematodes that lays the groundwork for future studies of their olfactory microcircuits. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. A second look at the structure of human olfactory memory.

    Science.gov (United States)

    White, Theresa L

    2009-07-01

    How do we remember olfactory information? Is the architecture of human olfactory memory unique compared with that of memory for other types of stimuli? Ten years ago, a review article evaluated these questions, as well as the distinction between long- and short-term olfactory memory, with three lines of evidence: capacity differences, coding differences, and neuropsychological evidence, though serial position effects were also considered. From the data available at the time, the article preliminarily suggested that olfactory memory was a two-component system that was not qualitatively different from memory systems for other types of stimuli. The decade that has elapsed since then has ushered in considerable changes in theories of memory structure and provided huge advances in neuroscience capabilities. Not only have many studies exploring various aspects of olfactory memory been published, but a model of olfactory perception that includes an integral unitary memory system also has been presented. Consequently, the structure of olfactory memory is reevaluated in the light of further information currently available with the same theoretical lines of evidence previously considered. This evaluation finds that the preponderance of evidence suggests that, as in memory for other types of sensory stimuli, the short-term-long-term distinction remains a valuable dissociation for conceptualizing olfactory memory, though perhaps not as architecturally separate systems.

  1. IGF1-Dependent Synaptic Plasticity of Mitral Cells in Olfactory Memory during Social Learning.

    Science.gov (United States)

    Liu, Zhihui; Chen, Zijun; Shang, Congping; Yan, Fei; Shi, Yingchao; Zhang, Jiajing; Qu, Baole; Han, Hailin; Wang, Yanying; Li, Dapeng; Südhof, Thomas C; Cao, Peng

    2017-07-05

    During social transmission of food preference (STFP), mice form long-term memory of food odors presented by a social partner. How does the brain associate a social context with odor signals to promote memory encoding? Here we show that odor exposure during STFP, but not unconditioned odor exposure, induces glomerulus-specific long-term potentiation (LTP) of synaptic strength selectively at the GABAergic component of dendrodendritic synapses of granule and mitral cells in the olfactory bulb. Conditional deletion of synaptotagmin-10, the Ca 2+ sensor for IGF1 secretion from mitral cells, or deletion of IGF1 receptor in the olfactory bulb prevented the socially relevant GABAergic LTP and impaired memory formation after STFP. Conversely, the addition of IGF1 to acute olfactory bulb slices elicited the GABAergic LTP in mitral cells by enhancing postsynaptic GABA receptor responses. Thus, our data reveal a synaptic substrate for a socially conditioned long-term memory that operates at the level of the initial processing of sensory information. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. On the olfactory anatomy in an archaic whale (Protocetidae, Cetacea) and the minke whale Balaenoptera acutorostrata (Balaenopteridae, Cetacea).

    Science.gov (United States)

    Godfrey, Stephen J; Geisler, Jonathan; Fitzgerald, Erich M G

    2013-02-01

    The structure of the olfactory apparatus is not well known in both archaic and extant whales; the result of poor preservation in most fossils and locational isolation deep within the skulls in both fossil and Recent taxa. Several specimens now shed additional light on the subject. A partial skull of an archaic cetacean is reported from the Pamunkey River, Virginia, USA. The specimen probably derives from the upper middle Eocene (Piney Point Formation) and is tentatively assigned to the Protocetidae. Uncrushed cranial cavities associated with the olfactory apparatus were devoid of sediment. CT scans clearly reveal the dorsal nasal meatus, ethmoturbinates within the olfactory recess, the cribriform plate, the area occupied by the olfactory bulbs, and the olfactory nerve tract. Several sectioned skulls of the minke whale (Balaenoptera acutorostrata) were also examined, and olfactory structures are remarkably similar to those observed in the fossil skull from the Pamunkey River. One important difference between the two is that the fossil specimen has an elongate olfactory nerve tract. The more forward position of the external nares in extant balaenopterids when compared with those of extant odontocetes is interpreted to be the result of the need to retain a functional olfactory apparatus and the forward position of the supraoccipital/cranial vertex. An increase in the distance between the occipital condyles and the vertex in balaenopterids enhances the mechanical advantage of the epaxial musculature that inserts on the occiput, a specialization that likely stabilizes the head of these enormous mammals during lunge feeding. Copyright © 2012 Wiley Periodicals, Inc.

  3. Olfactory fingerprints for major histocompatibility complex-determined body odors.

    Science.gov (United States)

    Schaefer, M L; Young, D A; Restrepo, D

    2001-04-01

    Recognition of individual body odors is analogous to human face recognition in that it provides information about identity. Individual body odors determined by differences at the major histocompatibility complex (MHC or H-2) have been shown to influence mate choice, pregnancy block, and maternal behavior in mice. Unfortunately, the mechanism and extent of the main olfactory bulb (MOB) and accessory olfactory bulb (AOB) involvement in the discrimination of animals according to H-2-type has remained ambiguous. Here we study the neuronal activation patterns evoked in the MOB in different individuals on exposure to these complex, biologically meaningful sensory stimuli. We demonstrate that body odors from H-2 disparate mice evoke overlapping but distinct maps of neuronal activation in the MOB. The spatial patterns of odor-evoked activity are sufficient to be used like fingerprints to predict H-2 identity using a novel computer algorithm. These results provide functional evidence for discrimination of H-2-determined body odors in the MOB, but do not preclude a role for the AOB. These data further our understanding of the neural strategies used to decode socially relevant odors.

  4. Development of organic membrane and biosensor. ; Artificial membrane chemical sensor on the model of olfactory cells. Seitaimaku to bio sensor no hatten. ; Kyusaibo wo model to shita jinkomaku kagaku sensor

    Energy Technology Data Exchange (ETDEWEB)

    Enomoto, S; Kashiwayanagi, M; Kurihara, K [Hokkaido University, Sapporo (Japan). Faculty of Pharmaceutical Science

    1991-05-05

    The olfactory cell is the most prominent chemical sensor to detect various kinds of external chemical substances with high sensibility. Consequently, on the model of such an organic chemical sensor mechanism, an artificial membrane with functions to detect and distinguish various chemical substances has been developed. In this study, a test using a lipid bimolecular membrane was carried out. As a result, it was found that the lipid bimolecular membrane showed membrane potential changes responding to various odorants. The mambrane with proper lipid composition presented almost the same sensibility to odorants as an olfactory organ. Response characteristic against various odors changed greatly due to the lipid composition and the addition of protein. It was also found that various odors can be discriminated by analyzing response information obtained from a lot of mambranes with different compositions Such ideas can be applied to the odor discrimination of the artificial membrane sensor. 14 refs., 13 figs.

  5. Species-specific control of cellular proliferation and the impact of large animal models for the use of olfactory ensheathing cells and Schwann cells in spinal cord repair.

    Science.gov (United States)

    Wewetzer, Konstantin; Radtke, Christine; Kocsis, Jeffery; Baumgärtner, Wolfgang

    2011-05-01

    Autologous transplantation of olfactory ensheathing cells (OECs) and Schwann cells (SCs) is considered a promising option to promote axonal regrowth and remyelination after spinal cord injury in humans. However, if the experimental data from the rodent model can be directly extrapolated to humans, as widely believed, remains to be established. While limitations of the rodent system have recently been discussed with regard to the distinct organization of the motor systems, the question whether OECs and SCs may display species-specific properties has not been fully addressed. Prompted by recent studies on canine and porcine glia, we performed a detailed analysis of the in vitro and in vivo properties of OECs and SCs and show that rodent but not human, monkey, porcine, and canine glia require mitogens for in vitro expansion, display a complex response to elevated intracellular cAMP, and undergo spontaneous immortalization upon prolonged mitogen stimulation. These data indicate fundamental inter-species differences of the control of cellular proliferation. Whether OECs and SCs from large animals and humans share growth-promoting in vivo properties with their rodent counterpart is not yet clear. Autologous implantation studies in humans did not reveal adverse effects of cell transplantation so far. However, in vivo studies of large animal or human glia and rodent recipients mainly focused on the remyelinating potential of the transplanted cells. Thus, further experimental in vivo studies in large animals are essential to fully define the axonal growth-promoting potential of OECs and SCs. Based on the homology of the in vitro growth control between porcine, canine and human glia, it is concluded that these species may serve as valuable translational models for scaling up human procedures. This article is part of a Special Issue entitled: Understanding olfactory ensheathing glia and their prospect for nervous system repair. Copyright © 2010 Elsevier Inc. All rights

  6. Jugular bulb diverticulum combined with high jugular bulb: a case report with CT and MRA findings

    International Nuclear Information System (INIS)

    Ko, Seog Wan

    2004-01-01

    Jugular bulb diverticulum is a rare condition that is characterized by the outpouching of the jugular bulb, and this can lead to hearing loss, tinnitus and vertigo. A few reports have revealed the radiologic findings about jugular bulb diverticulum, but none of them have described the MRA findings concerning this lesion. We present here the CT and MR venography findings in regards to a large high jugular blub and diverticulum we observed in a 47-year-old woman

  7. Jugular bulb diverticulum combined with high jugular bulb: a case report with CT and MRA findings

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Seog Wan [College of Medicine, Chonbuk National Univ., Jeonju (Korea, Republic of)

    2004-12-01

    Jugular bulb diverticulum is a rare condition that is characterized by the outpouching of the jugular bulb, and this can lead to hearing loss, tinnitus and vertigo. A few reports have revealed the radiologic findings about jugular bulb diverticulum, but none of them have described the MRA findings concerning this lesion. We present here the CT and MR venography findings in regards to a large high jugular blub and diverticulum we observed in a 47-year-old woman.

  8. From Batteries and Bulbs to High Tech.

    Science.gov (United States)

    Schwartz, Maurice L.; Schwartz, Ivan C.

    1986-01-01

    Presents a new, high-technology approach to making bulbs light in series and parallel circuits. Contains diagrams that illustrate the circuit patterns. Provides suggestions for applying the electronic principles that were addressed in the activities. (ML)

  9. Olfactory marker protein: turnover and transport in normal and regenerating neurons

    International Nuclear Information System (INIS)

    Kream, R.M.; Margolis, F.L.

    1984-01-01

    A 19,000-dalton acidic protein designated olfactory marker protein (OMP) is a cell-specific marker of mature olfactory chemosensory neurons. Intranasal irrigation of mouse olfactory epithelium with [ 35 S]methionine labeled OMP to high specific activity. Turnover and transport characteristics of 35 S-labeled OMP were compared to those of 35 S-labeled global cytosol protein in groups of young, adult, and Triton-treated adult mice. The latter contained primarily large numbers of regenerating olfactory neurons. In olfactory epithelium of young and Triton-treated mice, the specific activity of OMP was three times that of global cytosol protein, whereas in adults the two measures were equal. In all three groups, however, the rate of degradation of OMP was roughly equal to that of cytosol protein (T1/2 . 5 to 6 days). By contrast, differences in T1/2 for OMP decline in the bulb of adult, young, and Triton-treated adult mice were highly significant (T1/2's of 9.3, 6.1, and 4 to 5 days, respectively; p . 0.001). The specific activity of [35S]methionine incorporated in OMP exceeded that of the free amino acid 5-fold, indicating minimal precursor reutilization during the course of our experiments. Turnover data indicate that increased isotope incorporation into OMP in the epithelium is matched by an accelerated rate of degradation in the bulb. This may be correlated with the physiological state or developmental age of the primary neurons since in young and Triton-treated adult mice, rapidly maturing ''young'' olfactory neurons represent a larger proportion of the total population than in adults. Thus, OMP behaves as a typical, relatively slowly transported soluble protein (v . 2 to 4 mm/day, slow component b)

  10. Hydrodynamic Interactions Between Olfactory Appendages and Odor Plumes

    National Research Council Canada - National Science Library

    Koseff, Jeffrey

    2000-01-01

    .... A model lobster was then placed in the laboratory flume and we measured the odor concentration distribution around the olfactory appendage using high-speed video and laser-induced fluorescence techniques...

  11. Odorant responsiveness of embryonic mouse olfactory sensory neurons expressing the odorant receptors S1 or MOR23.

    Science.gov (United States)

    Lam, Rebecca S; Mombaerts, Peter

    2013-07-01

    The mammalian olfactory system has developed some functionality by the time of birth. There is behavioral and limited electrophysiological evidence for prenatal olfaction in various mammalian species. However, there have been no reports, in any mammalian species, of recordings from prenatal olfactory sensory neurons (OSNs) that express a given odorant receptor (OR) gene. Here we have performed patch-clamp recordings from mouse OSNs that express the OR gene S1 or MOR23, using the odorous ligands 2-phenylethyl alcohol or lyral, respectively. We found that, out of a combined total of 20 OSNs from embryos of these two strains at embryonic day (E)16.5 or later, all responded to a cognate odorous ligand. By contrast, none of six OSNs responded to the ligand at E14.5 or E15.5. The kinetics of the odorant-evoked electrophysiological responses of prenatal OSNs are similar to those of postnatal OSNs. The S1 and MOR23 glomeruli in the olfactory bulb are formed postnatally, but the axon terminals of OSNs expressing these OR genes may be synaptically active in the olfactory bulb at embryonic stages. The upper limit of the acquisition of odorant responsiveness for S1 and MOR23 OSNs at E16.5 is consistent with the developmental expression patterns of components of the olfactory signaling pathway. © 2013 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  12. Primary olfactory projections and the nervus terminalis in the African lungfish: implications for the phylogeny of cranial nerves.

    Science.gov (United States)

    von Bartheld, C S; Claas, B; Münz, H; Meyer, D L

    1988-08-01

    Primary olfactory and central projections of the nervus terminalis were investigated by injections of horseradish peroxidase into the olfactory epithelium in the African lungfish. In addition, gonadotropin-releasing hormone (GnRH) immunoreactivity of the nervus terminalis system was investigated. The primary olfactory projections are restricted to the olfactory bulb located at the rostral pole of the telencephalon; they do not extend into caudal parts of the telencephalon. A vomeronasal nerve and an accessory olfactory bulb could not be identified. The nervus terminalis courses through the dorsomedial telencephalon. Major targets include the nucleus of the anterior commissure and the nucleus praeopticus pars superior. some fibers cross to the contralateral side. A few fibers reach the diencephalon and mesencephalon. No label is present in the "posterior root of the nervus terminalis" (= "Pinkus's nerve" or "nervus praeopticus"). GnRH immunoreactivity is lacking in the "anterior root of the nervus terminalis," whereas it is abundant in nervus praeopticus (Pinkus's nerve). These findings may suggest that the nervus terminalis system originally consisted of two distinct cranial nerves, which have fused-in evolution-in most vertebrates. Theories of cranial nerve phylogeny are discussed in the light of the assumed "binerval origin" of the nervus terminalis system.

  13. Intrinsic and Extrinsic Neuromodulation of Olfactory Processing.

    Science.gov (United States)

    Lizbinski, Kristyn M; Dacks, Andrew M

    2017-01-01

    Neuromodulation is a ubiquitous feature of neural systems, allowing flexible, context specific control over network dynamics. Neuromodulation was first described in invertebrate motor systems and early work established a basic dichotomy for neuromodulation as having either an intrinsic origin (i.e., neurons that participate in network coding) or an extrinsic origin (i.e., neurons from independent networks). In this conceptual dichotomy, intrinsic sources of neuromodulation provide a "memory" by adjusting network dynamics based upon previous and ongoing activation of the network itself, while extrinsic neuromodulators provide the context of ongoing activity of other neural networks. Although this dichotomy has been thoroughly considered in motor systems, it has received far less attention in sensory systems. In this review, we discuss intrinsic and extrinsic modulation in the context of olfactory processing in invertebrate and vertebrate model systems. We begin by discussing presynaptic modulation of olfactory sensory neurons by local interneurons (LNs) as a mechanism for gain control based on ongoing network activation. We then discuss the cell-class specific effects of serotonergic centrifugal neurons on olfactory processing. Finally, we briefly discuss the integration of intrinsic and extrinsic neuromodulation (metamodulation) as an effective mechanism for exerting global control over olfactory network dynamics. The heterogeneous nature of neuromodulation is a recurring theme throughout this review as the effects of both intrinsic and extrinsic modulation are generally non-uniform.

  14. Metal X-ray microanalysis in the olfactory system of rainbow trout exposed to low level of copper

    International Nuclear Information System (INIS)

    Julliard, A.K.; Astic, L.; Saucier, D.

    1995-01-01

    It has recently been shown that a chronic copper exposure induces specific degeneration of olfactory receptor cells in rainbow trout; however, the exact mechanism of action of the metal is not yet known. Using X-ray microanalysis in transmission electron microscopy, we have studied the distribution of metal in the olfactory system of fish exposed for 15,30 and 60 days to 20 μg/l of copper. This was done in order to determine if it was accumulated in receptor cells and transported into the central nervous system via the olfactory nerve. No copper accumulation was detected either in the olfactory epithelium, in the olfactory nerve or in the olfactory bulb. The heavy metal was exclusively found within melanosomes of melanophores located in the lamina propria. After 60 days of exposure, the copper content in melanosomes was about two-fold higher than that in controls. As far as some morphological recovery took place in the olfactory organ during the metal exposure, which lets us suppose that some detoxication mechanism occurs, it could be suggested that metanophores might be somehow involved in such a mechanism. (authors). 57 refs., 15 figs

  15. Olfactory dysfunction in neuromyelitis optica spectrum disorders

    NARCIS (Netherlands)

    Zhang, L.J.; Zhao, N.; Fu, Y.; Zhang, D.Q.; Wang, J.; Qin, W.; Zhang, N.N.N.; Wood, K.; Liu, Y.; Yu, C.S.; Shi, F.D.; Yang, L.

    2015-01-01

    Few data were available for the understanding of olfactory function in neuromyelitis optica spectrum disorders (NMOSDs). The aims of our study were to investigate the incidence of olfactory dysfunction and characterize olfactory structures, using MRI, in patients with NMOSDs. Olfactory function was

  16. Roentgenologic image of penetrating duodenal bulb ulcer

    International Nuclear Information System (INIS)

    Strunin, A.E.

    1986-01-01

    When studying a series of aimed roentgenograms in patients with peptic ulcer a gas bubble of irregular spherical configuration or two-layer niche were determined near the bulb medial contour. Gas bubble was from 0.5-0.7 to 3.5 cm in diameter. In such cases penetrating ulcers were determined in operations. Along with other signs gas bubble symptom, sometimes two-layer signs may be used for timely and exact roentgenological diagnosis of penetrating duodenal bulb ulcer in peptic ulcer disease

  17. Sprout inhibition in roots, tubers and bulbs

    International Nuclear Information System (INIS)

    Luna C, P.C.

    1992-05-01

    The treatment with ionizing radiations to low dose impedes that appear sprouts in the tubers (potatoes); bulbs (onion and garlic) and in roots like the ginger and the yucca. The purpose is to inhibit the germination during the process of manipulation and storage, and this way to avoid the lost ones post crop of these products. The radiation dose required to inhibit the germination goes to depend of: the development conditions, the differences of variety, of the storage state of the bulbs and the conditions of cured and storage. (Author)

  18. Influence of vernalization and bulb size on the production of lily cut flowers and lily bulbs

    Directory of Open Access Journals (Sweden)

    Diogo Brito de Almeida

    2017-08-01

    Full Text Available Exposure of bulbs to cold, a physiological phenomenon called vernalization, and bulb size are important factors in the production of lily bulbs and flowers. This study aimed to verify the influence of vernalization of bulbs on flowering cut lily plants, as well as the impact of size and shape of harvest on the production and quality of flowers and bulbs. In turn, the way the stems of the plants used for cut-flower production are cropped is of higher importance for the production of new flower bulbs. In this sense, the experiment was conducted in Viçosa, MG, in a greenhouse in a randomized block design, in split splot scheme with three replications, in which the vernalization periods (25, 35 and 45 days at 4 ± 1 C constituted the plots; bulb sizes (diameters of 3.2-3.8 cm; 2.5-3.2 cm 1.9- and 2.5 cm, subplots and ways to harvest (full harvest of the stem at the required length for the commercial harvest of the flower, commercial stem harvest at the commercial length, maintaining 10cm of stem in the soil; removal of the floral buds as soon as their appearance is observed and harvest at the end of the season, the sub subplots. The bulbs were planted in beds, with 15 x 20 cm spacing. It was evaluated the number of plants that flowered and the number of flowers, the length and the diameter of the floral buds, fresh and dry weights, diameter and plant height as well as number, perimeter and amount of fresh and dry bulbs. There was a decrease in the plant height with the increase of the vernalization period and a reduction of the diameter of the planted bulbs, as well as of the number and the fresh and dry weights of the produced buds. The production of flowers and buds in number, size and weight was directly proportional to the size of the planted bulbs, while the form of harvest with removal of flower buds increased the number, the perimeter and the fresh and dry weights of the buds. Bulbs with diameter between 3.2 - 3.8 cm, stored for 25 days in

  19. Hydroponic technology for lily flowers and bulbs production using ...

    African Journals Online (AJOL)

    Aghomotsegin

    2015-07-22

    Jul 22, 2015 ... the utilization of the hydroponic technology to produce flower and bulb of Asiatic ... when they became 2 cm long and mother bulb scales were removed at ..... cell layer culture system in Lilium:Rgeneration and transformation.

  20. Olfactory identification deficits and associated response inhibition in obsessive-compulsive disorder: on the scent of the orbitofronto-striatal model.

    Science.gov (United States)

    Bersani, Giuseppe; Quartini, Adele; Ratti, Flavia; Pagliuca, Giulio; Gallo, Andrea

    2013-11-30

    Olfactory identification ability implicates the integrity of the orbitofrontal cortex (OFC). The fronto-striatal circuits including the OFC have been involved in the neuropathology of Obsessive Compulsive Disorder (OCD). However, only a few studies have examined olfactory function in patients with OCD. The Brief Smell Identification Test (B-SIT) and tests from the Cambridge Neuropsychological Automated Battery (CANTAB) were administered to 25 patients with OCD and to 21 healthy matched controls. OCD patients showed a significant impairment in olfactory identification ability as well as widely distributed cognitive deficits in visual memory, executive functions, attention, and response inhibition. The degree of behavioural impairment on motor impulsivity (prolonged response inhibition Stop-Signal Reaction Time) strongly correlated with the B-SIT score. Our study is the first to indicate a shared OFC pathological neural substrate underlying olfactory identification impairment, impulsivity, and OCD. Deficits in visual memory, executive functions and attention further indicate that regions outside of the orbitofronto-striatal loop may be involved in this disorder. Such results may help delineate the clinical complexity of OCD and support more targeted investigations and interventions. In this regard, research on the potential diagnostic utility of olfactory identification deficits in the assessment of OCD would certainly be useful. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  1. Neoseiulus paspalivorus, a predator from coconut, as a candidate for controlling dry bulb mites infesting stored tulip bulbs.

    Science.gov (United States)

    Lesna, Izabela; da Silva, Fernando R; Sato, Yukie; Sabelis, Maurice W; Lommen, Suzanne T E

    2014-06-01

    The dry bulb mite, Aceria tulipae, is the most important pest of stored tulip bulbs in The Netherlands. This tiny, eriophyoid mite hides in the narrow space between scales in the interior of the bulb. To achieve biological control of this hidden pest, candidate predators small enough to move in between the bulb scales are required. Earlier experiments have shown this potential for the phytoseiid mite, Neoseiulus cucumeris, but only after the bulbs were exposed to ethylene, a plant hormone that causes a slight increase in the distance between tulip bulb scales, just sufficient to allow this predator to reach the interior part of the bulb. Applying ethylene, however, is not an option in practice because it causes malformation of tulip flowers. In fact, to prevent this cosmetic damage, bulb growers ventilate rooms where tulip bulbs are stored, thereby removing ethylene produced by the bulbs (e.g. in response to mite or fungus infestation). Recently, studies on the role of predatory mites in controlling another eriophyoid mite on coconuts led to the discovery of an exceptionally small phytoseiid mite, Neoseiulus paspalivorus. This predator is able to move under the perianth of coconuts where coconut mites feed on meristematic tissue of the fruit. This discovery prompted us to test N. paspalivorus for its ability to control A. tulipae on tulip bulbs under storage conditions (ventilated rooms with bulbs in open boxes; 23 °C; storage period June-October). Using destructive sampling we monitored predator and prey populations in two series of replicated experiments, one at a high initial level of dry bulb mite infestation, late in the storage period, and another at a low initial dry bulb mite infestation, halfway the storage period. The first and the second series involved treatment with N. paspalivorus and a control experiment, but the second series had an additional treatment in which the predator N. cucumeris was released. Taking the two series of experiments together

  2. Olfactory granule cell development in normal and hyperthyroid rats.

    Science.gov (United States)

    Brunjes, P C; Schwark, H D; Greenough, W T

    1982-10-01

    Dendritic development was examined in olfactory bulbs of both normal 7-, 14-, 21- and 60-day-old rats and littermates treated on postnatal days 1-4 with 1 microgram/g body weight of L-thyroxine sodium. Tissue was processed via the Golgi-Cox technique and subjected to quantitative analyses of mitral and internal layer granule cell development. These populations of granule cells were selected because their pattern of late proliferation suggested potentially greater susceptibility to postnatal hormonal alterations. Although neonatal hyperthyroidism induces widespread acceleration of maturation, including precocious chemosensitivity, granule cell development was unaffected relative to littermate controls. Both normal and hyperthyroid groups exhibited an inverted U-shaped pattern of cellular development, with rapid dendritic dendritic growth and expansion occurring during the earliest ages tested, but with loss of processes and dendritic field size occurring after day 21.

  3. Constant Light Desynchronizes Olfactory versus Object and Visuospatial Recognition Memory Performance.

    Science.gov (United States)

    Tam, Shu K E; Hasan, Sibah; Choi, Harry M C; Brown, Laurence A; Jagannath, Aarti; Hughes, Steven; Hankins, Mark W; Foster, Russell G; Vyazovskiy, Vladyslav V; Bannerman, David M; Peirson, Stuart N

    2017-03-29

    Circadian rhythms optimize physiology and behavior to the varying demands of the 24 h day. The master circadian clock is located in the suprachiasmatic nuclei (SCN) of the hypothalamus and it regulates circadian oscillators in tissues throughout the body to prevent internal desynchrony. Here, we demonstrate for the first time that, under standard 12 h:12 h light/dark (LD) cycles, object, visuospatial, and olfactory recognition performance in C57BL/6J mice is consistently better at midday relative to midnight. However, under repeated exposure to constant light ( r LL), recognition performance becomes desynchronized, with object and visuospatial performance better at subjective midday and olfactory performance better at subjective midnight. This desynchrony in behavioral performance is mirrored by changes in expression of the canonical clock genes Period1 and Period2 ( Per1 and Per2 ), as well as the immediate-early gene Fos in the SCN, dorsal hippocampus, and olfactory bulb. Under r LL, rhythmic Per1 and Fos expression is attenuated in the SCN. In contrast, hippocampal gene expression remains rhythmic, mirroring object and visuospatial performance. Strikingly, Per1 and Fos expression in the olfactory bulb is reversed, mirroring the inverted olfactory performance. Temporal desynchrony among these regions does not result in arrhythmicity because core body temperature and exploratory activity rhythms persist under r LL. Our data provide the first demonstration that abnormal lighting conditions can give rise to temporal desynchrony between autonomous circadian oscillators in different regions, with different consequences for performance across different sensory domains. Such a dispersed network of dissociable circadian oscillators may provide greater flexibility when faced with conflicting environmental signals. SIGNIFICANCE STATEMENT A master circadian clock in the suprachiasmatic nuclei (SCN) of the hypothalamus regulates physiology and behavior across the 24 h day by

  4. Constant Light Desynchronizes Olfactory versus Object and Visuospatial Recognition Memory Performance

    Science.gov (United States)

    Tam, Shu K.E.; Hasan, Sibah; Brown, Laurence A.; Jagannath, Aarti; Hankins, Mark W.; Foster, Russell G.; Vyazovskiy, Vladyslav V.

    2017-01-01

    Circadian rhythms optimize physiology and behavior to the varying demands of the 24 h day. The master circadian clock is located in the suprachiasmatic nuclei (SCN) of the hypothalamus and it regulates circadian oscillators in tissues throughout the body to prevent internal desynchrony. Here, we demonstrate for the first time that, under standard 12 h:12 h light/dark (LD) cycles, object, visuospatial, and olfactory recognition performance in C57BL/6J mice is consistently better at midday relative to midnight. However, under repeated exposure to constant light (rLL), recognition performance becomes desynchronized, with object and visuospatial performance better at subjective midday and olfactory performance better at subjective midnight. This desynchrony in behavioral performance is mirrored by changes in expression of the canonical clock genes Period1 and Period2 (Per1 and Per2), as well as the immediate-early gene Fos in the SCN, dorsal hippocampus, and olfactory bulb. Under rLL, rhythmic Per1 and Fos expression is attenuated in the SCN. In contrast, hippocampal gene expression remains rhythmic, mirroring object and visuospatial performance. Strikingly, Per1 and Fos expression in the olfactory bulb is reversed, mirroring the inverted olfactory performance. Temporal desynchrony among these regions does not result in arrhythmicity because core body temperature and exploratory activity rhythms persist under rLL. Our data provide the first demonstration that abnormal lighting conditions can give rise to temporal desynchrony between autonomous circadian oscillators in different regions, with different consequences for performance across different sensory domains. Such a dispersed network of dissociable circadian oscillators may provide greater flexibility when faced with conflicting environmental signals. SIGNIFICANCE STATEMENT A master circadian clock in the suprachiasmatic nuclei (SCN) of the hypothalamus regulates physiology and behavior across the 24 h day by

  5. Ectopic gastric mucosa in the duodenal bulb

    International Nuclear Information System (INIS)

    Schnell, H.; Oehler, G.; Schulz, A.; Rau, W.S.; Giessen Univ.; Giessen Univ.

    1989-01-01

    The radiological and clinical findings of 12 patients with ectopic gastric mucosa in the duodenal bulb are presented. This is a defined disease with characteristic radiological features: multiple small nodular defects of the contrast medium of 1-3 mm diameter. Histology shows complete heterotopia. Pathogenesis and clinical significance are discussed with reference to the literature on this subject. (orig.) [de

  6. Organic Flower Bulbs From Holland - Outlook for the French Market

    NARCIS (Netherlands)

    Kamphuis, Elise

    2002-01-01

    The Netherlands is a major exporter of flower bulbs in the world. France is amongst the top10 of the biggest importers of Dutch flower bulbs. However, the growing of bulbs is very damaging to the environment. With the use of 1,5 million kilograms of pesticide and 16 million kilograms of artificial

  7. Bud abortion in tulip bulbs studied by magnetic resonance imaging

    NARCIS (Netherlands)

    Kilsdonk, van M.G.; Nicolaij, K.; Franssen, J.M.; Kollöffel, C.

    2002-01-01

    After storage and subsequent planting of flower bulbs, the flower bud frequently appears to be aborted. This physiological aberration is probably caused by a change in the water status of the bulb and may be initiated during storage. The development of bud abortion in tulip bulbs was studied during

  8. Lesion of the olfactory epithelium accelerates prion neuroinvasion and disease onset when prion replication is restricted to neurons.

    Directory of Open Access Journals (Sweden)

    Jenna Crowell

    Full Text Available Natural prion diseases of ruminants are moderately contagious and while the gastrointestinal tract is the primary site of prion agent entry, other mucosae may be entry sites in a subset of infections. In the current study we examined prion neuroinvasion and disease induction following disruption of the olfactory epithelium in the nasal mucosa since this site contains environmentally exposed olfactory sensory neurons that project directly into the central nervous system. Here we provide evidence for accelerated prion neuroinvasion and clinical onset from the olfactory mucosa after disruption and regeneration of the olfactory epithelium and when prion replication is restricted to neurons. In transgenic mice with neuron restricted replication of prions, there was a reduction in survival when the olfactory epithelium was disrupted prior to intranasal inoculation and there was >25% decrease in the prion incubation period. In a second model, the neurotropic DY strain of transmissible mink encephalopathy was not pathogenic in hamsters by the nasal route, but 50% of animals exhibited brain infection and/or disease when the olfactory epithelium was disrupted prior to intranasal inoculation. A time course analysis of prion deposition in the brain following loss of the olfactory epithelium in models of neuron-restricted prion replication suggests that neuroinvasion from the olfactory mucosa is via the olfactory nerve or brain stem associated cranial nerves. We propose that induction of neurogenesis after damage to the olfactory epithelium can lead to prion infection of immature olfactory sensory neurons and accelerate prion spread to the brain.

  9. Lesion of the Olfactory Epithelium Accelerates Prion Neuroinvasion and Disease Onset when Prion Replication Is Restricted to Neurons

    Science.gov (United States)

    Crowell, Jenna; Wiley, James A.; Bessen, Richard A.

    2015-01-01

    Natural prion diseases of ruminants are moderately contagious and while the gastrointestinal tract is the primary site of prion agent entry, other mucosae may be entry sites in a subset of infections. In the current study we examined prion neuroinvasion and disease induction following disruption of the olfactory epithelium in the nasal mucosa since this site contains environmentally exposed olfactory sensory neurons that project directly into the central nervous system. Here we provide evidence for accelerated prion neuroinvasion and clinical onset from the olfactory mucosa after disruption and regeneration of the olfactory epithelium and when prion replication is restricted to neurons. In transgenic mice with neuron restricted replication of prions, there was a reduction in survival when the olfactory epithelium was disrupted prior to intranasal inoculation and there was >25% decrease in the prion incubation period. In a second model, the neurotropic DY strain of transmissible mink encephalopathy was not pathogenic in hamsters by the nasal route, but 50% of animals exhibited brain infection and/or disease when the olfactory epithelium was disrupted prior to intranasal inoculation. A time course analysis of prion deposition in the brain following loss of the olfactory epithelium in models of neuron-restricted prion replication suggests that neuroinvasion from the olfactory mucosa is via the olfactory nerve or brain stem associated cranial nerves. We propose that induction of neurogenesis after damage to the olfactory epithelium can lead to prion infection of immature olfactory sensory neurons and accelerate prion spread to the brain. PMID:25822718

  10. Are olfactory receptors really olfactive?

    DEFF Research Database (Denmark)

    Giorgi, Franco; Maggio, Roberto; Bruni, Luis Emilio

    2011-01-01

    environmental conditions. By adopting this standpoint, the functional attribution as olfactory or chemotactic sensors to these receptors should not be seen neither as a cause conditioning receptor gene expression, nor as a final effect resulting from genetically predetermined programs, but as a direct...... and odor-decoding processes. However, this type of explanation does not entirely justify the role olfactory receptors have played during evolution, since they are also expressed ectopically in different organs and/or tissues. Homologous olfactory genes have in fact been found in such diverse cells and....../or organs as spermatozoa, testis and kidney where they are assumed to act as chemotactic sensors or renin modulators. To justify their functional diversity, homologous olfactory receptors are assumed to share the same basic role: that of conferring a self-identity to cells or tissues under varying...

  11. Effect of olive mill wastewater on growth and bulb production of tulip plants infected by bulb diseases

    Energy Technology Data Exchange (ETDEWEB)

    Lykas, C.; Vegalas, I.; Gougaulias, N.

    2014-06-01

    The effect of olive mill wastewater (OMW) on growth of tulip plants infected by common diseases as well as on their new bulbs production is analyzed in this work. Filtered and sterilized OMW was tested as growth inhibitor of Botrytis tulipae, Fusarium oxysporum, Aspergillus niger and Penicillium spp. mycelium. The effect of filtered OMW on uninfected tulip bulbs was also tested as well as on the growth of bulbs infected with the fungus B. tulipae and A. niger in vivo. The mycelium length, severity of scab-like lesions, plant height (PH), fresh mass (FM) and dry mass (DM) of plants and production of new bulbs were recorded. Only the filtered OMW inhibited the in vitro mycelium growth of all tested fungi. However filtered OMW caused infections when it sprayed on uninfected bulbs, malformations on 30% of the plants grown from these bulbs and decrease PH, FM and DM as well as new bulbs production at 75%, 72.4%, 79.1% and 50% respectively. The treatment of B. tulipae infected bulbs with filtered OMW reduced further the PH, FM, DM and the production of new bulbs in 92.1%, 81.4%, 78.7% and 97% respectively. In contrast the treatment of infected bulbs by B. tulipae + A. niger with filtered OMW did not affect PH, FM and the number of new bulbs produced and significantly improved plants DM and the mass of new bulbs. (Author)

  12. Effect of olive mill wastewater on growth and bulb production of tulip plants infected by bulb diseases

    Directory of Open Access Journals (Sweden)

    Christos Lykas

    2014-02-01

    Full Text Available The effect of olive mill wastewater (OMW on growth of tulip plants infected by common diseases as well as on their new bulbs production is analyzed in this work. Filtered and sterilized OMW was tested as growth inhibitor of Botrytis tulipae, Fusarium oxysporum, Aspergillus niger and Penicillium spp. mycelium. The effect of filtered OMW on uninfected tulip bulbs was also tested as well as on the growth of bulbs infected with the fungus B. tulipae and A. niger in vivo. The mycelium length, severity of scab-like lesions, plant height (PH, fresh mass (FM and dry mass (DM of plants and production of new bulbs were recorded. Only the filtered OMW inhibited the in vitro mycelium growth of all tested fungi. However filtered OMW caused infections when it sprayed on uninfected bulbs, malformations on 30% of the plants grown from these bulbs and decrease PH, FM and DM as well as new bulbs production at 75%, 72.4%, 79.1% and 50% respectively. The treatment of B. tulipae infected bulbs with filtered OMW reduced further the PH, FM, DM and the production of new bulbs in 92.1%, 81.4%, 78.7% and 97% respectively. In contrast the treatment of infected bulbs by B. tulipae + A. niger with filtered OMW did not affect PH, FM and the number of new bulbs produced and significantly improved plants DM and the mass of new bulbs.

  13. Genetic diversity of canine olfactory receptors

    Directory of Open Access Journals (Sweden)

    Hitte Christophe

    2009-01-01

    Full Text Available Abstract Background Evolution has resulted in large repertoires of olfactory receptor (OR genes, forming the largest gene families in mammalian genomes. Knowledge of the genetic diversity of olfactory receptors is essential if we are to understand the differences in olfactory sensory capability between individuals. Canine breeds constitute an attractive model system for such investigations. Results We sequenced 109 OR genes considered representative of the whole OR canine repertoire, which consists of more than 800 genes, in a cohort of 48 dogs of six different breeds. SNP frequency showed the overall level of polymorphism to be high. However, the distribution of SNP was highly heterogeneous among OR genes. More than 50% of OR genes were found to harbour a large number of SNP, whereas the rest were devoid of SNP or only slightly polymorphic. Heterogeneity was also observed across breeds, with 25% of the SNP breed-specific. Linkage disequilibrium within OR genes and OR clusters suggested a gene conversion process, consistent with a mean level of polymorphism higher than that observed for introns and intergenic sequences. A large proportion (47% of SNP induced amino-acid changes and the Ka/Ks ratio calculated for all alleles with a complete ORF indicated a low selective constraint with respect to the high level of redundancy of the olfactory combinatory code and an ongoing pseudogenisation process, which affects dog breeds differently. Conclusion Our demonstration of a high overall level of polymorphism, likely to modify the ligand-binding capacity of receptors distributed differently within the six breeds tested, is the first step towards understanding why Labrador Retrievers and German Shepherd Dogs have a much greater potential for use as sniffer dogs than Pekingese dogs or Greyhounds. Furthermore, the heterogeneity in OR polymorphism observed raises questions as to why, in a context in which most OR genes are highly polymorphic, a subset of

  14. Functional neuroanatomy of Drosophila olfactory memory formation.

    Science.gov (United States)

    Guven-Ozkan, Tugba; Davis, Ronald L

    2014-10-01

    New approaches, techniques and tools invented over the last decade and a half have revolutionized the functional dissection of neural circuitry underlying Drosophila learning. The new methodologies have been used aggressively by researchers attempting to answer three critical questions about olfactory memories formed with appetitive and aversive reinforcers: (1) Which neurons within the olfactory nervous system mediate the acquisition of memory? (2) What is the complete neural circuitry extending from the site(s) of acquisition to the site(s) controlling memory expression? (3) How is information processed across this circuit to consolidate early-forming, disruptable memories to stable, late memories? Much progress has been made and a few strong conclusions have emerged: (1) Acquisition occurs at multiple sites within the olfactory nervous system but is mediated predominantly by the γ mushroom body neurons. (2) The expression of long-term memory is completely dependent on the synaptic output of α/β mushroom body neurons. (3) Consolidation occurs, in part, through circuit interactions between mushroom body and dorsal paired medial neurons. Despite this progress, a complete and unified model that details the pathway from acquisition to memory expression remains elusive. © 2014 Guven-Ozkan and Davis; Published by Cold Spring Harbor Laboratory Press.

  15. Synaptic degeneration and remodelling after fast kindling of the olfactory bulb

    DEFF Research Database (Denmark)

    Woldbye, D P; Bolwig, T G; Kragh, J

    1996-01-01

    in the basolateral amygdala and dentate gyrus, suggesting that these regions may be functionally altered during the kindling process. In the piriform cortex and dentate gyrus increased NCAM/D3(SNAP-25) ratios found ipsilaterally at seven days after kindling probably reflect an elevated rate of synaptic remodelling...

  16. Regulation of granule cell excitability by a low-threshold calcium spike in turtle olfactory bulb

    DEFF Research Database (Denmark)

    Pinato, Giulietta; Midtgaard, Jens

    2003-01-01

    of the cell usually increased their amplitude so that they more easily boosted Na spike initiation. The LTS persisted in the presence of TTX but was antagonized by blockers of T-type calcium channels. The voltage dependence, kinetics, and inactivation properties of the LTS were characteristic of a low......-threshold calcium spike. The threshold of the LTS was slightly above the resting potential but well below the Na spike threshold, and the LTS was often evoked in isolation in normal medium. Tetraethylammonium (TEA) and 4-aminopyridine (4-AP) had only minimal effects on the LTS but revealed the presence of a high...

  17. Connectivity from OR37 expressing olfactory sensory neurons to distinct cell types in the hypothalamus

    Directory of Open Access Journals (Sweden)

    Andrea eBader

    2012-11-01

    Full Text Available Olfactory sensory neurons which express a member from the OR37 subfamily of odorant receptor genes are wired to the main olfactory bulb in a unique monoglomerular fashion; from these glomeruli an untypical connectivity into higher brain centers exists. In the present study we have investigated by DiI and transsynaptic tracing approaches how the connection pattern from these glomeruli into distinct hypothalamic nuclei is organized. The application of DiI onto the ventral domain of the bulb which harbors the OR37 glomeruli resulted in the labeling of fibers within the paraventricular and supraoptic nucleus of the hypothalamus; some of these fibers were covered with varicose-like structures. No DiI-labeled cell somata were detectable in these nuclei. The data indicate that projection neurons which originate in the OR37 region of the main olfactory bulb form direct connections into these nuclei. The cells that were labeled by the transsynaptic tracer WGA in these nuclei were further characterized. Their distribution pattern in the paraventricular nucleus was reminiscent of cells which produce distinct neuropeptides. Double labeling experiments confirmed that they contained vasopressin, but not the related neuropeptide oxytocin. Morphological analysis revealed that they comprise of magno- and parvocellular cells. A comparative investigation of the WGA-positive cells in the supraoptic nucleus demonstrated that these were vasopressin-positive, as well, whereas oxytocin-producing cells of this nucleus also contained no transsynaptic tracer. Together, the data demonstrate a connectivity from OR37 expressing sensory neurons to distinct hypothalamic neurons with the same neuropeptide content.

  18. Olfactory short-term memory encoding and maintenance - an event-related potential study.

    Science.gov (United States)

    Lenk, Steffen; Bluschke, Annet; Beste, Christian; Iannilli, Emilia; Rößner, Veit; Hummel, Thomas; Bender, Stephan

    2014-09-01

    This study examined whether the memory encoding and short term maintenance of olfactory stimuli is associated with neurophysiological activation patterns which parallel those described for sensory modalities such as vision and auditory. We examined olfactory event-related potentials in an olfactory change detection task in twenty-four healthy adults and compared the measured activation to that found during passive olfactory stimulation. During the early olfactory post-processing phase, we found a sustained negativity over bilateral frontotemporal areas in the passive perception condition which was enhanced in the active memory task. There was no significant lateralization in either experimental condition. During the maintenance interval at the end of the delay period, we still found sustained activation over bilateral frontotemporal areas which was more negative in trials with correct - as compared to incorrect - behavioural responses. This was complemented by a general significantly stronger frontocentral activation. Summarizing, we were able to show that olfactory short term memory involves a parallel sequence of activation as found in other sensory modalities. In addition to olfactory-specific frontotemporal activations in the memory encoding phase, we found slow cortical potentials over frontocentral areas during the memory maintenance phase indicating the activation of a supramodal memory maintenance system. These findings could represent the neurophysiological underpinning of the 'olfactory flacon', the olfactory counter-part to the visual sketchpad and phonological loop embedded in Baddeley's working memory model. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. Increased Regenerative Capacity of the Olfactory Epithelium in Niemann–Pick Disease Type C1

    Directory of Open Access Journals (Sweden)

    Anja Meyer

    2017-04-01

    Full Text Available Niemann–Pick disease type C1 (NPC1 is a fatal neurovisceral lysosomal lipid storage disorder. The mutation of the NPC1 protein affects the homeostasis and transport of cholesterol and glycosphingolipids from late endosomes/lysosomes to the endoplasmic reticulum resulting in progressive neurodegeneration. Since olfactory impairment is one of the earliest symptoms in many neurodegenerative disorders, we focused on alterations of the olfactory epithelium in an NPC1 mouse model. Previous findings revealed severe morphological and immunohistochemical alterations in the olfactory system of NPC1−/− mutant mice compared with healthy controls (NPC1+/+. Based on immunohistochemical evaluation of the olfactory epithelium, we analyzed the impact of neurodegeneration in the olfactory epithelium of NPC1−/− mice and observed considerable loss of mature olfactory receptor neurons as well as an increased number of proliferating and apoptotic cells. Additionally, after administration of two different therapy approaches using either a combination of miglustat, 2-hydroxypropyl-β-cyclodextrin (HPβCD and allopregnanolone or a monotherapy with HPβCD, we recorded a remarkable reduction of morphological damages in NPC1−/− mice and an up to four-fold increase of proliferating cells within the olfactory epithelium. Numbers of mature olfactory receptor neurons doubled after both therapy approaches. Interestingly, we also observed therapy-induced alterations in treated NPC1+/+ controls. Thus, olfactory testing may provide useful information to monitor pharmacologic treatment approaches in human NPC1.

  20. Smelly primes – when olfactory primes do or do not work

    Directory of Open Access Journals (Sweden)

    Monique A Smeets

    2014-02-01

    Full Text Available In applied olfactory cognition the effects that olfactory stimulation can have on (human behavior are investigated. To enable an efficient application of olfactory stimuli a model of how they may lead to a change in behavior is proposed. To this end we use the concept of olfactory priming. Olfactory priming may prompt a special view on priming as the olfactory sense has some unique properties which make odors special types of primes. Examples of such properties are the ability of odors to influence our behavior outside of awareness, to lead to strong affective evaluations, to evoke specific memories, and to associate easily and quickly to other environmental stimuli. Opportunities and limitations for using odors as primes are related to these properties, and alternative explanations for reported findings are offered. Implications for olfactory semantic, construal, behavior and goal priming are given based on a brief overview of the priming literature from social psychology and from olfactory perception science. We end by formulating recommendations and ideas for a future research agenda and applications for olfactory priming.

  1. Discordance between olfactory psychophysical measurements and olfactory event related potentials in five patients with olfactory dysfunction following upper respiratory infection.

    Science.gov (United States)

    Guan, Jing; Ni, Dao-feng; Wang, Jian; Gao, Zhi-qiang

    2009-07-05

    Subjective olfactory tests are easy to perform and popularly applied in the clinic, but using only these, it is difficult to diagnose all disorders of the olfactory system. The olfactory event related potentials technique offers further insight into the olfactory system and is an ideal objective test. This analysis was of subjective and objective data on the olfactory function of twelve patients with loss of smell associated with an upper respiratory infection (URI). We tested the twelve patients with URI induced olfactory loss by medical history, physical examination of the head and neck, olfactory tests and medical imaging. Olfactory function was assessed by Toyota and Takagi olfactometry including olfactory detection and recognition thresholds and olfactory event-related potentials (OERPs) recorded with OEP-98C Olfactometer. An unusual phenomenon was observed in five patients in whom the subjective detection and recognition thresholds were normal, while the expected OERPs were not detectable. We suggest that the discordance between olfactory psychophysical measurements and OERPs might be the results of abnormal electrophysiology related with olfactory neuropathy caused by viral URI. In addition, the measurement of OERPs might play a significant role in evaluating olfactory dysfunction.

  2. Discordance between olfactory psychophysical measurements and olfactory event related potentials in five patients with olfactory dysfunction following upper respiratory infection

    Institute of Scientific and Technical Information of China (English)

    GUAN Jing; NI Dao-feng; WANG Jian; GAO Zhi-qiang

    2009-01-01

    Background Subjective olfactory tests are easy to perform and popularly applied in the clinic, but using only these, it is difficult to diagnose all disorders of the olfactory system. The olfactory event related potentials technique offers further insight into the olfactory system and is an ideal objective test. This analysis was of subjective and objective data on the olfactory function of twelve patients with loss of smell associated with an upper respiratory infection (URI). Methods We tested the twelve patients with URI induced olfactory loss by medical history, physical examination of the head and neck, olfactory tests and medical imaging. Olfactory function was assessed by Toyota and Takagi olfactometry including olfactory detection and recognition thresholds and olfactory event-related potentials (OERPs) recorded with OEP-98C Olfactometer. Results An unusual phenomenon was observed in five patients in whom the subjective detection and recognition thresholds were normal, while the expected OERPs were not detectable. Conclusions We suggest that the discordance between olfactory psychophysical measurements and OERPs might be the results of abnormal electrephysiology related with olfactory neuropathy caused by viral URI. In addition, the measurement of OERPs might play a significant role in evaluating olfactory dysfunction.

  3. Effects of blood-feeding on olfactory sensitivity of the malaria mosquito Anopheles gambiae: application of mixed linear models to account for repeated measurements

    NARCIS (Netherlands)

    Qiu, Y.T.; Gort, G.; Torricelli, A.; Takken, W.; Loon, van J.J.A.

    2013-01-01

    Olfaction plays an important role in the host-seeking behavior of the malaria mosquito Anopheles gambiae. After a complete blood meal, female mosquitoes will not engage in host-seeking behavior until oviposition has occurred. We investigated if peripheral olfactory sensitivity changed after a blood

  4. Cellular Mechanisms of Action of Drug Abuse on Olfactory Neurons

    Directory of Open Access Journals (Sweden)

    Thomas Heinbockel

    2015-12-01

    Full Text Available Cannabinoids (Δ9-tetrahydrocannabinol are the active ingredient of marijuana (cannabis which is the most commonly abused illicit drug in the USA. In addition to being known and used as recreational drugs, cannabinoids are produced endogenously by neurons in the brain (endocannabinoids and serve as important signaling molecules in the nervous system and the rest of the body. Cannabinoids have been implicated in bodily processes both in health and disease. Recent pharmacological and physiological experiments have described novel aspects of classic brain signaling mechanisms or revealed unknown mechanisms of cellular communication involving the endocannabinoid system. While several forms of signaling have been described for endocannabinoids, the most distinguishing feature of endocannabinoids is their ability to act as retrograde messengers in neural circuits. Neurons in the main olfactory bulb express high levels of cannabinoid receptors. Here, we describe the cellular mechanisms and function of this novel brain signaling system in regulating neural activity at synapses in olfactory circuits. Results from basic research have the potential to provide the groundwork for translating the neurobiology of drug abuse to the realm of the pharmacotherapeutic treatment of addiction, specifically marijuana substance use disorder.

  5. Fos Expression in the Olfactory Pathway of High- and Low-Sexually Performing Rams Exposed to Urine from Estrous or Ovariectomized Ewes

    Science.gov (United States)

    Mirto, AJ; Austin, KJ; Uthlaut, VA; Roselli, CE; Alexander, BM

    2015-01-01

    Exposure to estrous ewe urine stimulates investigation and mounting activity in sexually active but not sexually inactive rams. It was hypothesized sexual indifference may result from an inability to detect olfactory cues or an interruption of the pathway from detection of the olfactory stimulus to the motor response. Sexually active (n=4) and inactive (n=3) rams were exposed to urine from estrous ewes. An additional group of sexually active rams (n=3) were exposed to urine from ovariectomized ewes. Rams were exsanguinated following 1 h of exposure to stimulus. Neural activity was determined in tissues of interest by the presence of fos and fos-related proteins detected by immunohistochemistry procedures. Sexually active rams exposed to urine from ovariectomized ewes had more (P ≤ 0.05) fos-positive cells in the olfactory bulb, but fewer (P = 0.03) fos-positive cells in the cortical amygdala compared to sexually active rams exposed to urine from estrous ewes. Sexually inactive rams had similar (P ≥ 0.13) numbers of fos positive neurons in the olfactory bulb and medial amygdala but fewer (P ≤ 0.04) in the central amygdala, bed nucleus of the stria terminalis and the medial preoptic area compared to sexually active rams exposed to urine from estrous ewes. Sexual inactivity was not associated with decreased hypothalamic function since fos activity was similar (P ≥ 0.14) among groups in the suprachiasmatic and ventral medial nucleus. Sexual inactivity is not likely due to an impaired ability to detect or process olfactory stimuli by the main olfactory bulb and medial-cortical amygdala. Sexually inactive rams may have reduced attentiveness to sexual stimuli and/or decreased responsiveness of regions in the brain which regulate reproductive behaviors. PMID:28348447

  6. Mucuna pruriens (Velvet bean) rescues motor, olfactory, mitochondrial and synaptic impairment in PINK1B9 Drosophila melanogaster genetic model of Parkinson's disease.

    Science.gov (United States)

    Poddighe, Simone; De Rose, Francescaelena; Marotta, Roberto; Ruffilli, Roberta; Fanti, Maura; Secci, Pietro Paolo; Mostallino, Maria Cristina; Setzu, Maria Dolores; Zuncheddu, Maria Antonietta; Collu, Ignazio; Solla, Paolo; Marrosu, Francesco; Kasture, Sanjay; Acquas, Elio; Liscia, Anna

    2014-01-01

    The fruit fly Drosophila melanogaster (Dm) mutant for PTEN-induced putative kinase 1 (PINK1B9) gene is a powerful tool to investigate physiopathology of Parkinson's disease (PD). Using PINK1B9 mutant Dm we sought to explore the effects of Mucuna pruriens methanolic extract (Mpe), a L-Dopa-containing herbal remedy of PD. The effects of Mpe on PINK1B9 mutants, supplied with standard diet to larvae and adults, were assayed on 3-6 (I), 10-15 (II) and 20-25 (III) days old flies. Mpe 0.1% significantly extended lifespan of PINK1B9 and fully rescued olfactory response to 1-hexanol and improved climbing behavior of PINK1B9 of all ages; in contrast, L-Dopa (0.01%, percentage at which it is present in Mpe 0.1%) ameliorated climbing of only PINK1B9 flies of age step II. Transmission electron microscopy analysis of antennal lobes and thoracic ganglia of PINK1B9 revealed that Mpe restored to wild type (WT) levels both T-bars and damaged mitochondria. Western blot analysis of whole brain showed that Mpe, but not L-Dopa on its own, restored bruchpilot (BRP) and tyrosine hydroxylase (TH) expression to age-matched WT control levels. These results highlight multiple sites of action of Mpe, suggesting that its effects cannot only depend upon its L-Dopa content and support the clinical observation of Mpe as an effective medication with intrinsic ability of delaying the onset of chronic L-Dopa-induced long-term motor complications. Overall, this study strengthens the relevance of using PINK1B9 Dm as a translational model to study the properties of Mucuna pruriens for PD treatment.

  7. Mucuna pruriens (Velvet bean) Rescues Motor, Olfactory, Mitochondrial and Synaptic Impairment in PINK1B9 Drosophila melanogaster Genetic Model of Parkinson’s Disease

    Science.gov (United States)

    Ruffilli, Roberta; Fanti, Maura; Secci, Pietro Paolo; Mostallino, Maria Cristina; Setzu, Maria Dolores; Zuncheddu, Maria Antonietta; Collu, Ignazio; Solla, Paolo; Marrosu, Francesco; Kasture, Sanjay; Acquas, Elio; Liscia, Anna

    2014-01-01

    The fruit fly Drosophila melanogaster (Dm) mutant for PTEN-induced putative kinase 1 (PINK1B9) gene is a powerful tool to investigate physiopathology of Parkinson's disease (PD). Using PINK1B9 mutant Dm we sought to explore the effects of Mucuna pruriens methanolic extract (Mpe), a L-Dopa-containing herbal remedy of PD. The effects of Mpe on PINK1B9 mutants, supplied with standard diet to larvae and adults, were assayed on 3–6 (I), 10–15 (II) and 20–25 (III) days old flies. Mpe 0.1% significantly extended lifespan of PINK1B9 and fully rescued olfactory response to 1-hexanol and improved climbing behavior of PINK1B9 of all ages; in contrast, L-Dopa (0.01%, percentage at which it is present in Mpe 0.1%) ameliorated climbing of only PINK1B9 flies of age step II. Transmission electron microscopy analysis of antennal lobes and thoracic ganglia of PINK1B9 revealed that Mpe restored to wild type (WT) levels both T-bars and damaged mitochondria. Western blot analysis of whole brain showed that Mpe, but not L-Dopa on its own, restored bruchpilot (BRP) and tyrosine hydroxylase (TH) expression to age-matched WT control levels. These results highlight multiple sites of action of Mpe, suggesting that its effects cannot only depend upon its L-Dopa content and support the clinical observation of Mpe as an effective medication with intrinsic ability of delaying the onset of chronic L-Dopa-induced long-term motor complications. Overall, this study strengthens the relevance of using PINK1B9 Dm as a translational model to study the properties of Mucuna pruriens for PD treatment. PMID:25340511

  8. Mucuna pruriens (Velvet bean rescues motor, olfactory, mitochondrial and synaptic impairment in PINK1B9 Drosophila melanogaster genetic model of Parkinson's disease.

    Directory of Open Access Journals (Sweden)

    Simone Poddighe

    Full Text Available The fruit fly Drosophila melanogaster (Dm mutant for PTEN-induced putative kinase 1 (PINK1B9 gene is a powerful tool to investigate physiopathology of Parkinson's disease (PD. Using PINK1B9 mutant Dm we sought to explore the effects of Mucuna pruriens methanolic extract (Mpe, a L-Dopa-containing herbal remedy of PD. The effects of Mpe on PINK1B9 mutants, supplied with standard diet to larvae and adults, were assayed on 3-6 (I, 10-15 (II and 20-25 (III days old flies. Mpe 0.1% significantly extended lifespan of PINK1B9 and fully rescued olfactory response to 1-hexanol and improved climbing behavior of PINK1B9 of all ages; in contrast, L-Dopa (0.01%, percentage at which it is present in Mpe 0.1% ameliorated climbing of only PINK1B9 flies of age step II. Transmission electron microscopy analysis of antennal lobes and thoracic ganglia of PINK1B9 revealed that Mpe restored to wild type (WT levels both T-bars and damaged mitochondria. Western blot analysis of whole brain showed that Mpe, but not L-Dopa on its own, restored bruchpilot (BRP and tyrosine hydroxylase (TH expression to age-matched WT control levels. These results highlight multiple sites of action of Mpe, suggesting that its effects cannot only depend upon its L-Dopa content and support the clinical observation of Mpe as an effective medication with intrinsic ability of delaying the onset of chronic L-Dopa-induced long-term motor complications. Overall, this study strengthens the relevance of using PINK1B9 Dm as a translational model to study the properties of Mucuna pruriens for PD treatment.

  9. Sensory memory for odors is encoded in spontaneous correlated activity between olfactory glomeruli.

    Science.gov (United States)

    Galán, Roberto F; Weidert, Marcel; Menzel, Randolf; Herz, Andreas V M; Galizia, C Giovanni

    2006-01-01

    Sensory memory is a short-lived persistence of a sensory stimulus in the nervous system, such as iconic memory in the visual system. However, little is known about the mechanisms underlying olfactory sensory memory. We have therefore analyzed the effect of odor stimuli on the first odor-processing network in the honeybee brain, the antennal lobe, which corresponds to the vertebrate olfactory bulb. We stained output neurons with a calcium-sensitive dye and measured across-glomerular patterns of spontaneous activity before and after a stimulus. Such a single-odor presentation changed the relative timing of spontaneous activity across glomeruli in accordance with Hebb's theory of learning. Moreover, during the first few minutes after odor presentation, correlations between the spontaneous activity fluctuations suffice to reconstruct the stimulus. As spontaneous activity is ubiquitous in the brain, modifiable fluctuations could provide an ideal substrate for Hebbian reverberations and sensory memory in other neural systems.

  10. [New data on olfactory control of estral receptivity of female rats].

    Science.gov (United States)

    Satli, M A; Aron, C

    1976-03-01

    Olfactory bulb deprivation increased sexual receptivity in 4-day cyclic female rats on the late afternoon of prooestrus (6-7, p.m.). The proportion of receptive females was higher in bulbectomized (B) than in sham operated (SH) animals. On the contrary the same proportion of B and SH females mated in the evening of prooestrus (10. 30-11. 30 p.m.). An increased lordosis quotient was observed in the B females at either of these two stages of the cycle.

  11. Bulb turbine operating at medium head: XIA JIANG case study

    International Nuclear Information System (INIS)

    Loiseau, F; Desrats, C; Petit, P; Liu, J

    2012-01-01

    With lots of references for 4-blade bulb turbines, such as these of Wu Jin Xia (4 units – 36.1 MW per unit – 9.2 m rated head), Chang Zhou (15 units – 46.7 MW per unit – 9.5 m rated head) and Tong Wan (4 units – 46.2 MW per unit – 11 m rated head), ALSTOM Power Hydro is one of the major suppliers of bulb turbines operating under medium head for the Chinese market. ALSTOM Power Hydro has been awarded in November 2010 a contract by Jiang Xi Province Xia Jiang Water Control Project Headquarters to equip Xia Jiang's new hydropower plant. The power dam is located on the Gan Jiang river, at about 160 km away from Nan Chang town in South Eastern China. The supply will consist in 5 bulb units including the furniture of both the turbine and its generator, for a total capacity of 200 MW, under a rated net head of 8.6 m. The prototype turbine is a 7.8 m diameter runner, rotating at 71.4 rpm speed. For this project, ALSTOM has proposed a fully new design of 4-blade bulb runner. This paper outlines the main steps of the hydraulic development. First of all, a fine tuning of the blade geometry was performed to enhance the runner behaviour at high loads and low heads, so that to fulfill the demanding requirements of efficiencies and maximum output. The challenge was also to keep an excellent cavitation behaviour, especially at the outer blade diameter in order to avoid cavitation erosion on the prototype. The shape of the blade was optimized by using the latest tools in computational fluid dynamics. Steady state simulations of the distributor and the runner were performed, in order to simulate more accurately the pressure fields on the blade and the velocity distribution at the outlet of the runner. Moreover, draft tube computations have been performed close to the design point and at higher loads. Then, a model fully homologous with the prototype was manufactured and tested at ALSTOM's laboratory in Grenoble (France). The model test results confirmed the predicted

  12. Bulb turbine operating at medium head: XIA JIANG case study

    Science.gov (United States)

    Loiseau, F.; Desrats, C.; Petit, P.; Liu, J.

    2012-11-01

    With lots of references for 4-blade bulb turbines, such as these of Wu Jin Xia (4 units - 36.1 MW per unit - 9.2 m rated head), Chang Zhou (15 units - 46.7 MW per unit - 9.5 m rated head) and Tong Wan (4 units - 46.2 MW per unit - 11 m rated head), ALSTOM Power Hydro is one of the major suppliers of bulb turbines operating under medium head for the Chinese market. ALSTOM Power Hydro has been awarded in November 2010 a contract by Jiang Xi Province Xia Jiang Water Control Project Headquarters to equip Xia Jiang's new hydropower plant. The power dam is located on the Gan Jiang river, at about 160 km away from Nan Chang town in South Eastern China. The supply will consist in 5 bulb units including the furniture of both the turbine and its generator, for a total capacity of 200 MW, under a rated net head of 8.6 m. The prototype turbine is a 7.8 m diameter runner, rotating at 71.4 rpm speed. For this project, ALSTOM has proposed a fully new design of 4-blade bulb runner. This paper outlines the main steps of the hydraulic development. First of all, a fine tuning of the blade geometry was performed to enhance the runner behaviour at high loads and low heads, so that to fulfill the demanding requirements of efficiencies and maximum output. The challenge was also to keep an excellent cavitation behaviour, especially at the outer blade diameter in order to avoid cavitation erosion on the prototype. The shape of the blade was optimized by using the latest tools in computational fluid dynamics. Steady state simulations of the distributor and the runner were performed, in order to simulate more accurately the pressure fields on the blade and the velocity distribution at the outlet of the runner. Moreover, draft tube computations have been performed close to the design point and at higher loads. Then, a model fully homologous with the prototype was manufactured and tested at ALSTOM's laboratory in Grenoble (France). The model test results confirmed the predicted ones: the

  13. Structural model and trans-interaction of the entire ectodomain of the olfactory cell adhesion molecule

    DEFF Research Database (Denmark)

    Kulahin, Nikolaj; Kristensen, Ole; Rasmussen, Kim K

    2011-01-01

    of six recombinant proteins corresponding to different regions of the ectodomain. The model is the longest experimentally based composite structural model of an entire IgCAM ectodomain. It displays an essentially linear arrangement of IgI-V, followed by bends between IgV and Fn3I and between Fn3I and Fn3...

  14. Interglomerular Connectivity within the Canonical and GC-D/Necklace Olfactory Subsystems.

    Directory of Open Access Journals (Sweden)

    Cedric R Uytingco

    Full Text Available The mammalian main olfactory system contains several subsystems that differ not only in the receptors they express and the glomerular targets they innervate within the main olfactory bulb (MOB, but also in the strategies they use to process odor information. The canonical main olfactory system employs a combinatorial coding strategy that represents odorant identity as a pattern of glomerular activity. By contrast, the "GC-D/necklace" olfactory subsystem-formed by olfactory sensory neurons expressing the receptor guanylyl cyclase GC-D and their target necklace glomeruli (NGs encircling the caudal MOB-is critical for the detection of a small number of semiochemicals that promote the acquisition of food preferences. The formation of these socially-transmitted food preferences requires the animal to integrate information about two types of olfactory stimuli: these specialized social chemosignals and the food odors themselves. However, the neural mechanisms with which the GC-D/necklace subsystem processes this information are unclear. We used stimulus-induced increases in intrinsic fluorescence signals to map functional circuitry associated with NGs and canonical glomeruli (CGs in the MOB. As expected, CG-associated activity spread laterally through both the glomerular and external plexiform layers associated with activated glomeruli. Activation of CGs or NGs resulted in activity spread between the two types of glomeruli; there was no evidence of preferential connectivity between individual necklace glomeruli. These results support previous anatomical findings that suggest the canonical and GC-D/necklace subsystems are functionally connected and may integrate general odor and semiochemical information in the MOB.

  15. Selective enhancement of main olfactory input to the medial amygdala by GnRH.

    Science.gov (United States)

    Blake, Camille Bond; Meredith, Michael

    2010-03-04

    In male hamsters mating behavior is dependent on chemosensory input from the main olfactory and vomeronasal systems, whose central pathways contain cell bodies and fibers of gonadotropin-releasing hormone (GnRH) neurons. In sexually naive males, vomeronasal organ removal (VNX), but not main olfactory lesions, impairs mating behavior. Intracerebroventricular (i.c.v.)-GnRH restores mating in sexually naive VNX males and enhances medial amygdala (Me) immediate-early gene activation by chemosensory stimulation. In sexually experienced males, VNX does not impair mating and i.c.v.-GnRH suppresses Me activation. Thus, the main olfactory system is sufficient for mating in experienced-VNX males, but not in naive-VNX males. We investigated the possibility that GnRH enhances main olfactory input to the amygdala in naive-VNX males using i.c.v.-GnRH and pharmacological stimulation (bicuculline/D,L-homocysteic acid mixture) of the main olfactory bulb (MOB). In sexually naive intact males there was a robust increase of Fos protein expression in the anteroventral medial amygdala (MeAv) with MOB stimulation, but no effect of GnRH. There was no effect of stimulation or GnRH in posterodorsal medial amygdala (MePd). In naive-VNX animals, GnRH increased Fos in MeAv and MePv. Only combined MOB stimulation and i.c.v.-GnRH produced a significant increase in Fos in the dorsal (reproduction-related) portion of MeP (MePd). When the animals were sexually experienced before VNX, a condition in which GnRH does not enhance mating, i.c.v.-GnRH combined with MOB stimulation suppressed Fos expression in MePd. This suggests a more selective effect of GnRH on olfactory input in MePd than elsewhere in medial amygdala of VNX males. 2009 Elsevier B.V. All rights reserved.

  16. Urban air pollution: influences on olfactory function and pathology in exposed children and young adults.

    Science.gov (United States)

    Calderón-Garcidueñas, Lilian; Franco-Lira, Maricela; Henríquez-Roldán, Carlos; Osnaya, Norma; González-Maciel, Angelica; Reynoso-Robles, Rafael; Villarreal-Calderon, Rafael; Herritt, Lou; Brooks, Diane; Keefe, Sheyla; Palacios-Moreno, Juan; Villarreal-Calderon, Rodolfo; Torres-Jardón, Ricardo; Medina-Cortina, Humberto; Delgado-Chávez, Ricardo; Aiello-Mora, Mario; Maronpot, Robert R; Doty, Richard L

    2010-01-01

    Mexico City (MC) residents are exposed to severe air pollution and exhibit olfactory bulb inflammation. We compared the olfactory function of individuals living under conditions of extreme air pollution to that of controls from a relatively clean environment and explore associations between olfaction scores, apolipoprotein E (APOE) status, and pollution exposure. The olfactory bulbs (OBs) of 35 MC and 9 controls 20.8+/-8.5 years were assessed by light and electron microscopy. The University of Pennsylvania Smell Identification Test (UPSIT) was administered to 62 MC/25 controls 21.2+/-2.7 years. MC subjects had significantly lower UPSIT scores: 34.24+/-0.42 versus controls 35.76+/-0.40, p=0.03. Olfaction deficits were present in 35.5% MC and 12% of controls. MC APOE epsilon 4 carriers failed 2.4+/-0.54 items in the 10-item smell identification scale from the UPSIT related to Alzheimer's disease, while APOE 2/3 and 3/3 subjects failed 1.36+/-0.16 items, p=0.01. MC residents exhibited OB endothelial hyperplasia, neuronal accumulation of particles (2/35), and immunoreactivity to beta amyloid betaA(42) (29/35) and/or alpha-synuclein (4/35) in neurons, glial cells and/or blood vessels. Ultrafine particles were present in OBs endothelial cytoplasm and basement membranes. Control OBs were unremarkable. Air pollution exposure is associated with olfactory dysfunction and OB pathology, APOE 4 may confer greater susceptibility to such abnormalities, and ultrafine particles could play a key role in the OB pathology. This study contributes to our understanding of the influences of air pollution on olfaction and its potential contribution to neurodegeneration. Copyright 2009 Elsevier GmbH. All rights reserved.

  17. An olfactory ‘stress test’ may detect preclinical Alzheimer’s disease

    Directory of Open Access Journals (Sweden)

    Schofield Peter W

    2012-05-01

    Full Text Available Abstract Background The olfactory bulb (OB receives extensive cholinergic input from the basal forebrain and is affected very early in Alzheimer’s disease (AD. We speculated that an olfactory ‘stress test’ (OST, targeting the OB, might be used to unmask incipient AD. We investigated if change in olfactory performance following intranasal atropine was associated with several known antecedents or biomarkers of AD. Methods We measured change in performance on the University of Pennsylvania Smell Identification Test (UPSIT in the left nostril before (20-items and after (remaining 20-items intranasal administration of 1 mg of atropine. We administered cognitive tests, measured hippocampal volume from MRI scans and recorded Apolipoprotein E genotype as indices relevant to underlying AD. Results In a convenience sample of 56 elderly individuals (14 probable AD, 13 cognitive impairment no dementia, 29 cognitively intact the change in UPSIT score after atropine (‘atropine effect’ = AE correlated significantly with demographically scaled episodic memory score (r = 0.57, p Conclusions The OST using atropine as an olfactory probe holds promise as a simple, inexpensive screen for early and preclinical AD and further work, including longitudinal studies, is needed to explore this possibility.

  18. The mouse olfactory peduncle. 3. Development of neurons, glia and centrifugal afferents

    Directory of Open Access Journals (Sweden)

    Peter eBrunjes

    2014-06-01

    Full Text Available The present series of studies was designed to provide a general overview of the development of the region connecting the olfactory bulb to the forebrain. The olfactory peduncle contains several structures involved in processing odor information with the anterior olfactory nucleus (cortex being the largest and most studied. Results indicate that considerable growth occurs in the peduncle from postnatal day (P10-P20, with reduced expansion from P20-P30. No evidence was found for the addition of new projection or interneurons during the postnatal period. GABAergic cells decreased in both number and density after P10. Glial populations exhibited different patterns of development, with astrocytes declining in density from P10-P30, and both oligodendrocytes and microglia increasing through the interval. Myelination in the anterior commissure emerged between P11-14. Dense cholinergic innervation was observed at P10 and remained relatively stable through P30, while considerable maturation of serotonergic innervation occurred through the period. Unilateral naris occlusion from P1-P30 resulted in about a 30% reduction in the size of the ipsilateral peduncle but few changes were observed on the contralateral side. The ipsilateral peduncle also exhibited higher densities of GAD67- containing interneurons and cholinergic fibers suggesting a delay in normal developmental pruning. Lower densities of interneurons expressing CCK, somatostatin and NPY and in myelin basic protein staining were also observed. Understanding variations in developmental trajectories within the olfactory peduncle may be an important tool for unravelling the functions of the region.

  19. Connections of the corticomedial amygdala in the golden hamster. II. Efferents of the ''olfactory amygdala''

    International Nuclear Information System (INIS)

    Kevetter, G.A.; Winans, S.S.

    1981-01-01

    The anterior cortical (C1) and posterolateral cortical (C2) nuclei of the amygdala are designated the ''olfactory amygdala'' because they each receive direct projections from the main olfactory bulb. The efferents of these nuclei were traced after stereotaxic placement of 1-5 muCi tritiated proline in the corticomedial amygdala of the male golden hamsters. Following survival times of 12, 24, or 48 hours, 20 micron frozen sections of the brains were processed for light microscopic autoradiography. Efferents from C2 terminate in layers II and III of the olfactory tubercle and in layer Ib of pars ventralis and pars medialis of the anterior olfactory nucleus. Fibers from this nucleus also project to layers I and II of the infralimbic cortex and to the molecular layer of the agranular insular cortex. More posteriorly, fibers from C2 terminate in layer I of the dorsolateral entorhinal cortex, and in the endopiriform nucleus. From C1, efferent fibers travel in the stria terminalis and terminate in the precommissural bed nucleus of the stria terminalis and in the mediobasal hypothalamus. Efferents from C1 also innervate the molecular layer of C2, the amygdalo-hippocampal area, and the adjacent piriform cortex. Neurons in both C1 and C2 project to the molecular layer of the medial amygdaloid nucleus and the posteromedial cortical nucleus of the amygdala, the plexiform layer of the ventral subiculum, and the molecular layer of the lateral entorhinal cortex

  20. Differential Axonal Projection of Mitral and Tufted Cells in the Mouse Main Olfactory System

    Directory of Open Access Journals (Sweden)

    Shin Nagayama

    2010-09-01

    Full Text Available In the past decade, much has been elucidated regarding the functional organization of the axonal connection of olfactory sensory neurons to olfactory bulb (OB glomeruli. However, the manner in which projection neurons of the OB process odorant input and send this information to higher brain centers remains unclear. Here, we report long-range, large-scale tracing of the axonal projection patterns of OB neurons using two-photon microscopy. Tracer injection into a single glomerulus demonstrated widely distributed mitral/tufted cell axonal projections on the lateroventral surface of the mouse brain, including the anterior/posterior piriform cortex (PC and olfactory tubercle (OT. We noted two distinct groups of labeled axons: PC-orienting axons and OT-orienting axons. Each group occupied distinct parts of the lateral olfactory tract. PC-orienting axons projected axon collaterals to a wide area of the PC but only a few collaterals to the OT. OT-orienting axons densely projected axon collaterals primarily to the anterolateral OT (alOT. Different colored dye injections into the superficial and deep portions of the OB external plexiform layer revealed that the PC-orienting axon populations originated in presumed mitral cells and the OT-orienting axons in presumed tufted cells. These data suggest that although mitral and tufted cells receive similar odor signals from a shared glomerulus, they process the odor information in different ways and send their output to different higher brain centers via the PC and alOT.

  1. Olfactory groove meningiomas.

    Science.gov (United States)

    Hentschel, Stephen J; DeMonte, Franco

    2003-06-15

    Olfactory groove meningiomas (OGMs) arise over the cribriform plate and may reach very large sizes prior to presentation. They can be differentiated from tuberculum sellae meningiomas because OGMs arise more anterior in the skull base and displace the optic nerve and chiasm inferiorly rather than superiorly. The authors searched the neurosurgery database at the M. D. Anderson Cancer Center for cases of OGM treated between 1993 and 2003. The records of these patients were then reviewed retrospectively for details regarding clinical presentation, imaging findings, surgical results and complications, and follow-up status. Thirteen patients, (12 women and one man, mean age 56 years) harbored OGMs (mean size 5.7 cm). All patients underwent bifrontal craniotomies and biorbital osteotomies. There were 11 complete resections (including the hyperostotic bone and dura of the cribriform plate and any extension into the ethmoid sinuses) and two subtotal resections with minimal residual tumor left in patients with recurrent lesions. No complication directly due to the surgery occurred in any patient. There were no recurrences in a mean follow-up period of 2 years (range 0-5 years). With current microsurgical techniques, the results of OGM resection are excellent, with a high rate of total resection and a low incidence of complications. All hyperostotic bone should be removed with the dura of the anterior skull base to minimize the risk of recurrence.

  2. The European Commission's light bulb decree: Another costly regulation?

    International Nuclear Information System (INIS)

    Frondel, Manuel; Lohmann, Steffen

    2011-01-01

    Since September 2009, Regulation 244/2009 of the European Commission enforces the gradual phase-out of incandescent light bulbs. As of September 2012, only energy-efficient lighting sources will be allowed for sale. Among these are halogen light bulbs, light-emitting diodes (LED), or compact fluorescent light bulbs-often referred to as energy-saving light bulbs. The Commission's justification for the phase-out of conventional light bulbs maintains that a reduction in the electricity consumed will not only lead to lower energy cost for private households and industrial consumers, but at the same time lead to a decrease in greenhouse gas emissions. This article discusses possible reasons for the slow market diffusion of energy-saving light bulbs and shows that the investment in energy-efficient light bulbs does not necessarily lead to significant cost reductions. Drawing on some illustrative examples, we demonstrate that the use of cheaper incandescent bulbs instead of energy-saving light bulbs can be economically rational in cases of rather low usage times, in which the higher initial purchasing price might only pay off after very long time spans. Furthermore, due to the coexistence with the European Emissions Trading Scheme (ETS), this regulation attains no additional emission reductions beyond those achieved by the ETS alone. We thus conclude that the general ban of incandescent light bulbs is inappropriate and should be abolished by the Commission. - Research highlights: → This article discusses reasons for the slow market diffusion of energy-saving light bulbs. → We show that using incandescent bulbs can be rational in cases of rather low usage times. → We conclude that the general ban of incandescent light bulbs should be abolished by the Commission.

  3. Olfactory Receptor Database: a sensory chemoreceptor resource

    OpenAIRE

    Skoufos, Emmanouil; Marenco, Luis; Nadkarni, Prakash M.; Miller, Perry L.; Shepherd, Gordon M.

    2000-01-01

    The Olfactory Receptor Database (ORDB) is a WWW-accessible database that has been expanded from an olfactory receptor resource to a chemoreceptor resource. It stores data on six classes of G-protein-coupled sensory chemoreceptors: (i) olfactory receptor-like proteins, (ii) vomeronasal receptors, (iii) insect olfactory receptors, (iv) worm chemoreceptors, (v) taste papilla receptors and (vi) fungal pheromone receptors. A complementary database of the ligands of these receptors (OdorDB) has bee...

  4. Olfactory Memory Impairment in Neurodegenerative Diseases

    OpenAIRE

    Bahuleyan, Biju; Singh, Satendra

    2012-01-01

    Olfactory disorders are noted in a majority of neurodegenerative diseases, but they are often misjudged and are rarely rated in the clinical setting. Severe changes in the olfactory tests are observed in Parkinson's disease. Olfactory deficits are an early feature in Alzheimer's disease and they worsen with the disease progression. Alterations in the olfactory function are also noted after severe head injuries, temporal lobe epilepsy, multiple sclerosis, and migraine. The purpose of the prese...

  5. Which bulb is brighter? It depends on connection! Strategies for illuminating electrical concepts using light bulbs

    Science.gov (United States)

    Wong, Darren; Lee, Paul; Foong, S. K.

    2017-11-01

    In this paper, we examined teachers’ understanding of electrical concepts such as power, current and potential difference based on how these concepts were applied to understand the relative brightness seen in bulbs of different wattage under different connections—series or parallel. From the responses of teachers to a concept question, we identified common lines of reasoning and the associated conceptual difficulties. To support the explanation of the concept question, we set up relevant circuits and made measurements of the circuits. We discuss the temperature dependence of the resistance of the light bulb which although critical for in depth understanding of the relative brightness, was often omitted in the teacher responses. Lastly, we share insights and strategies to elicit and confront students' thinking and to help them resolve, extend and apply their thinking with regard to the related electrical concepts using various light bulb activities.

  6. Processing of Sensory Information in the Olfactory System

    DEFF Research Database (Denmark)

    The olfactory system is an attractive model system due to the easy control of sensory input and the experimental accessibility in animal studies. The odorant signals are processed from receptor neurons to a neural network of mitral and granular cells while various types of nonlinear behaviour can...... and equation-free techniques allow for a better reproduction and understanding of recent experimental findings. Talks: Olfaction as a Model System for Sensory-Processing Neural Networks (Jens Midtgaard, University of Copenhagen, Denmark) Nonlinear Effects of Signal Transduction in Olfactory Sensory Neurons...

  7. Olfactory memory: a case study in cognitive psychology.

    Science.gov (United States)

    Annett, J M

    1996-05-01

    Over the last decade, interest in the general applicability of psychological research has increased significantly, leading to doubts among some critics of cognitive psychology regarding the usefulness of the modern information-processing approach. In particular, current cognitive models of memory address mainly visual and verbal information processing, with little acknowledgement of the existence of other sensory modalities. However, since the mid-1970's, the literature on olfactory memory has expanded rapidly, and it has remained relatively independent of mainstream memory research. This article outlines the olfactory literature, which has focused principally on examination of the Proustian characteristics of smell. The relationship between olfactory and other types of memory is also examined. The author notes that there is evidence that models of memory intended to be general have taken insufficient account of findings from olfaction and other sensory modalities, an approach that could be considered symptomatic of dangerous tendency to base purportedly general theories on databases that are too narrow.

  8. Effect of irradiation on olfactory function

    International Nuclear Information System (INIS)

    Aiba, Tsunemasa; Sugimoto, Midori; Matsuda, Yasuaki; Sugiura, Yoshikazu; Nakai, Yoshiaki; Nakajima, Toshifumi

    1990-01-01

    The effects of therapeutic irradiation on olfactory function were investigated in 20 patients who received radiation therapy because of a malignant tumor of the nose or paranasal sinuses. The standard olfaction test with a T and T olfactometer and an intravenous olfaction test were given before the radiation therapy, during the period of radiation therapy and 1, 3, 6 and 12 months or more later. Five patients whose olfactory epithelium was outside the radiation field showed no damage to olfactory function. The olfactory function of the other 15 patients whose olfactory epithelium had been exposed to radiation was not obviously changed or damaged at the time of radiation therapy. However, 6 months after irradiation, some patients showed a decline in olfactory function, and after 12 months, 4 of 7 patients showed severe damage to olfactory function. These results suggest that a therapeutic dose of irradiation will not cause severe damage to the olfactory function during the period of radiation therapy, but could cause delayed olfactory disorders in some patients after a few years. These olfactory disorders might be caused by damage to or degeneration of the olfactory epithelium or olfactory nerve. (author)

  9. Traumatic brain injury and olfactory deficits

    DEFF Research Database (Denmark)

    Fortin, Audrey; Lefebvre, Mathilde Beaulieu; Ptito, Maurice

    2010-01-01

    . Between 40-44% of the patients showing olfactory impairments were not aware of their deficit. CONCLUSIONS: Since a significant proportion of the patients showing olfactory impairments were not aware of their deficit, it is recommended than clinicians systematically evaluate olfactory functions using...

  10. Olfactory insights into sleep-dependent learning and memory.

    Science.gov (United States)

    Shanahan, Laura K; Gottfried, Jay A

    2014-01-01

    Sleep is pervasive throughout most of the animal kingdom-even jellyfish and honeybees do it. Although the precise function of sleep remains elusive, research increasingly suggests that sleep plays a key role in memory consolidation. Newly formed memories are highly labile and susceptible to interference, and the sleep period offers an optimal window in which memories can be strengthened or modified. Interestingly, a small but growing research area has begun to explore the ability of odors to modulate memories during sleep. The unique anatomical organization of the olfactory system, including its intimate overlap with limbic systems mediating emotion and memory, and the lack of a requisite thalamic intermediary between the nasal periphery and olfactory cortex, suggests that odors may have privileged access to the brain during sleep. Indeed, it has become clear that the long-held assumption that odors have no impact on the sleeping brain is no longer tenable. Here, we summarize recent studies in both animal and human models showing that odor stimuli experienced in the waking state modulate olfactory cortical responses in sleep-like states, that delivery of odor contextual cues during sleep can enhance declarative memory and extinguish fear memory, and that olfactory associative learning can even be achieved entirely within sleep. Data reviewed here spotlight the emergence of a new research area that should hold far-reaching implications for future neuroscientific investigations of sleep, learning and memory, and olfactory system function. © 2014 Elsevier B.V. All rights reserved.

  11. Quantum Dot Distribution in the Olfactory Epithelium After Nasal Delivery

    Science.gov (United States)

    Garzotto, D.; De Marchis, S.

    2010-10-01

    Nanoparticles are used in a wide range of human applications from industrial to bio-medical fields. However, the unique characteristics of nanoparticles, such as the small size, large surface area per mass and high reactivity raises great concern on the adverse effects of these particles on ecological systems and human health. There are several pioneer studies reporting translocation of inhaled particulates to the brain through a potential neuronal uptake mediated by the olfactory nerve (1, 2, 3). However, no direct evidences have been presented up to now on the pathway followed by the nanoparticles from the nose to the brain. In addition to a neuronal pathway, nanoparticles could gain access to the central nervous system through extracellular pathways (perineuronal, perivascular and cerebrospinal fluid paths). In the present study we investigate the localization of intranasally delivered fluorescent nanoparticles in the olfactory epithelium. To this purpose we used quantum dots (QDs), a model of innovative fluorescent semiconductor nanocrystals commonly used in cell and animal biology (4). Intranasal treatments with QDs were performed acutely on adult CD1 mice. The olfactory epithelium was collected and analysed by confocal microscopy at different survival time after treatment. Data obtained indicate that the neuronal components of the olfactory epithelium are not preferentially involved in QDs uptake, thus suggesting nanoparticles can cross the olfactory epithelium through extracellular pathways.

  12. Reliability of the Bulb Dynamometer for Assessing Grip Strength

    Directory of Open Access Journals (Sweden)

    Colleen Maher

    2018-04-01

    Full Text Available Background: Hand function is an overall indicator of health and is often measured using grip strength. Handheld dynamometry is the most common method of measuring grip strength. The purpose of this study was to determine the inter-rater and test-retest reliability, the reliability of one trial versus three trials, and the preliminary norms for a young adult population using the Baseline® Pneumatic Squeeze Bulb Dynamometer (30 psi. Methods: This study used a one-group methodological design. One hundred and three healthy adults (30 males and 73 females were recruited. Six measurements were collected for each hand per participant. The data was analyzed using Intraclass Correlation Coefficients (ICC two-way effects model (2,2 and paired-samples t-tests. Results: The ICC for inter-rater reliability ranged from 0.955 to 0.977. Conclusion: The results of this study suggest that the bulb dynamometer is a reliable tool to measure grip strength and should be further explored for reliable and valid use in diverse populations and as an alternative to the Jamar dynamometer.

  13. Serine/threonine-protein phosphatase 1 α levels are paralleling olfactory memory formation in the CD1 mouse.

    Science.gov (United States)

    Winding, Christiana; Sun, Yanwei; Höger, Harald; Bubna-Littitz, Hermann; Pollak, Arnold; Schmidt, Peter; Lubec, Gert

    2011-06-01

    Although olfactory discrimination has already been studied in several mouse strains, data on protein levels linked to olfactory memory are limited. Wild mouse strains Mus musculus musculus, Mus musculus domesticus and CD1 laboratory outbred mice were tested in a conditioned odor preference task and trained to discriminate between two odors, Rose and Lemon, by pairing one odor with a sugar reward. Six hours following the final test, mice were sacrificed and olfactory bulbs (OB) were taken for gel-based proteomics analyses and immunoblotting. OB proteins were extracted, separated by 2-DE and quantified using specific software (Proteomweaver). Odor-trained mice showed a preference for the previously rewarded odor suggesting that conditioned odor preference occurred. In CD1 mice levels, one out of 482 protein spots was significantly increased in odor-trained mice as compared with the control group; it was in-gel digested by trypsin and chymotrypsin and analyzed by tandem mass spectrometry (nano-ESI-LC-MS/MS). The spot was unambiguously identified as serine/threonine-protein phosphatase PP1-α catalytic subunit (PP-1A) and differential levels observed in gel-based proteomic studies were verified by immunoblotting. PP-1A is a key signalling element in synaptic plasticity and memory processes and is herein shown to be paralleling olfactory discrimination representing olfactory memory. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Neurobiological correlates of visual and olfactory recognition in sheep.

    Science.gov (United States)

    Kendrick, K M

    1994-12-01

    ability to selectively recognise the odour signatures of its own lambs within the first few hours of giving birth. Electrophysiological recordings from mitral cells in the olfactory bulb have shown that none of them respond preferentially to lamb odours pre-partum, when the ewes show no interest in lambs, whereas 60% of them do so after ewes have bonded with their lambs. A sub-population of mitral cells also responds differentially to own and alien lamb odours post-partum. Neurochemical studies have shown that lamb odours do not evoke transmitter release within the olfactory bulb pre-partum whereas, post-partum, own lamb odours stimulate release of the intrinsic amino acid transmitters, GABA and glutamate whereas both own and alien lamb odours evoke equivalent increases in the release of the centrifugal pathway transmitters, acetylcholine and nonadrenaline. Overall these experiments provide compelling evidence that the sheep, which is after all a social animal, makes use of sophisticated visual cues from the face and body and of olfactory cues from the body and wool to recognise different individuals. The neural pathways which are involved in both of these recognition processes also show remarkable evidence of plasticity. However, there appears to be a much closer link between recognition and emotional significance demonstrated in the coding strategies employed by the neural circuits involved in individual recognition in the sheep brain compared to that of a primate and, indeed, they seem to be organised more for identifying a small number of different categories of individuals rather than for a large number of individuals per se. It is possible therefore that social evolutionary pressures to specifically identify large numbers of individuals of similar emotional significance has been achieved by weakening the organisational influence of affect on coding strategies of cells in the temporal cortex in favour of a more extensive feature detection system allowing accurate

  15. Qualitative and quantitative changes in phospholipids and proteins investigated by spectroscopic techniques in olfactory bulbectomy animal depression model.

    Science.gov (United States)

    Depciuch, J; Parlinska-Wojtan, M

    2018-01-30

    Depression becomes nowadays a high mortality civilization disease with one of the potential causes being impaired smell. In this study Raman, Fourier Transform Infra Red (FTIR) and Ultraviolet-Visible (UV-vis) spectroscopies were used to determine the changes in the quantity and structure of phospholipids and proteins in the blood serum of bulbectomized rats (OB_NaCl), which is a common animal depression model. The efficiency of amitriptyline (AMI) treatment was also evaluated. The obtained results show a significant decrease in the phospholipid and protein fractions (as well as changes in their secondary structures) in blood serum of bulbectomized rats. AMI treatment in bulbectomized rats increased protein level and did not affect the level of phospholipids. Structural information from phospholipids and proteins was obtained from UV-vis spectroscopy combined with the second derivative of the FTIR spectra. Indeed, the structure of proteins in blood serum of bulbectomized rats was normalized after amitriptyline therapy, while the damaged structure of phospholipids remained unaffected. These findings strongly suggest that impaired smell could be one of the causes of depression and may induce permanent (irreversible) damages into the phospholipid structure identified as shortened carbon chains. This study shows a possible new application of spectroscopic techniques in the diagnosis and therapy monitoring of depression. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Olfactory memory impairment in neurodegenerative diseases.

    Science.gov (United States)

    Bahuleyan, Biju; Singh, Satendra

    2012-10-01

    Olfactory disorders are noted in a majority of neurodegenerative diseases, but they are often misjudged and are rarely rated in the clinical setting. Severe changes in the olfactory tests are observed in Parkinson's disease. Olfactory deficits are an early feature in Alzheimer's disease and they worsen with the disease progression. Alterations in the olfactory function are also noted after severe head injuries, temporal lobe epilepsy, multiple sclerosis, and migraine. The purpose of the present review was to discuss the available scientific knowledge on the olfactory memory and to relate its impairment with neurodegenerative diseases.

  17. Women have better olfactory perception for wine aromas

    Directory of Open Access Journals (Sweden)

    Wurz Douglas André

    2017-01-01

    in the olfactory bulb, which is the brain region responsible for smell detection.

  18. An Olfactory Cinema: Smelling Perfume

    Directory of Open Access Journals (Sweden)

    Jiaying Sim

    2014-09-01

    Full Text Available While technological improvements from the era of silent movies to that of sound cinema have altered and continued to affect audience’s cinematic experiences, the question is not so much how technology has increased possibility of a sensory response to cinema, rather, it is one that exposes how such technological changes only underscore the participation of our senses and the body in one’s experience of watching film, highlighting the inherently sensorial nature of the cinematic experience. This paper aims to address the above question through an olfactory cinema, by close analysis of Perfume: The Story of a Murderer (2006 by Tom Tykwer. What is an olfactory cinema, and how can such an approach better our understanding of sensorial aspects found within a cinema that ostensibly favours audio-visual senses? What can we benefit from an olfactory cinema? Perhaps, it is through an olfactory cinema that one may begin to embrace the sensual quality of cinema that has been overshadowed by the naturalized ways of experiencing films solely with our eyes and ears, so much so that we desensitize ourselves to the role our senses play in cinematic experiences altogether

  19. Olfactory memory traces in Drosophila.

    Science.gov (United States)

    Berry, Jacob; Krause, William C; Davis, Ronald L

    2008-01-01

    In Drosophila, the fruit fly, coincident exposure to an odor and an aversive electric shock can produce robust behavioral memory. This behavioral memory is thought to be regulated by cellular memory traces within the central nervous system of the fly. These molecular, physiological, or structural changes in neurons, induced by pairing odor and shock, regulate behavior by altering the neurons' response to the learned environment. Recently, novel in vivo functional imaging techniques have allowed researchers to observe cellular memory traces in intact animals. These investigations have revealed interesting temporal and spatial dynamics of cellular memory traces. First, a short-term cellular memory trace was discovered that exists in the antennal lobe, an early site of olfactory processing. This trace represents the recruitment of new synaptic activity into the odor representation and forms for only a short period of time just after training. Second, an intermediate-term cellular memory trace was found in the dorsal paired medial neuron, a neuron thought to play a role in stabilizing olfactory memories. Finally, a long-term protein synthesis-dependent cellular memory trace was discovered in the mushroom bodies, a structure long implicated in olfactory learning and memory. Therefore, it appears that aversive olfactory associations are encoded by multiple cellular memory traces that occur in different regions of the brain with different temporal domains.

  20. Experimental and numerical study on inlet and outlet conditions of a bulb turbine with considering free surface

    International Nuclear Information System (INIS)

    Zhao, Y P; Liao, W L; Feng, H D; Ruan, H; Luo, X Q

    2012-01-01

    For a bulb turbine, it has a low head and a big runner diameter, and the free surface influences the flow at the inlet and outlet of the turbine, which bring many problems such as vibration, cracks and cavitation to the turbine. Therefore, it is difficult to get the precise internal flow characteristics through a numerical simulation with conventional ideal flow conditions. In this paper, both numerical and experimental methods are adopted to investigate the flow characteristics at the inlet and outlet of the bulb turbine with considering free surface. Firstly, experimental and numerical studies in a low head pressure pipeline are conducted, and the corresponding boundary condition according with reality is obtained through the comparison between the model test result and the CFD simulation result. Then, through an analysis of the velocity and pressure fields at the inlet of the bulb turbine at different heads, the flow characteristics and rules at the entrance of the bulb turbine have been revealed with considering free surface; Finally, the performance predictions for a bulb turbine have been conducted by using the obtained flow rules at the inlet as the boundary condition of a turbine, and the causes that lead to non-uniform forces on blades, cavitation and vibration have been illustrated in this paper, which also provide a theory basis for an accurate numerical simulation and optimization design of a bulb turbine.

  1. Olfactory training in patients with Parkinson's disease.

    Directory of Open Access Journals (Sweden)

    Antje Haehner

    Full Text Available OBJECTIVE: Decrease of olfactory function in Parkinson's disease (PD is a well-investigated fact. Studies indicate that pharmacological treatment of PD fails to restore olfactory function in PD patients. The aim of this investigation was whether patients with PD would benefit from "training" with odors in terms of an improvement of their general olfactory function. It has been hypothesized that olfactory training should produce both an improved sensitivity towards the odors used in the training process and an overall increase of olfactory function. METHODS: We recruited 70 subjects with PD and olfactory loss into this single-center, prospective, controlled non-blinded study. Thirty-five patients were assigned to the olfactory training group and 35 subjects to the control group (no training. Olfactory training was performed over a period of 12 weeks while patients exposed themselves twice daily to four odors (phenyl ethyl alcohol: rose, eucalyptol: eucalyptus, citronellal: lemon, and eugenol: cloves. Olfactory testing was performed before and after training using the "Sniffin' Sticks" (thresholds for phenyl ethyl alcohol, tests for odor discrimination, and odor identification in addition to threshold tests for the odors used in the training process. RESULTS: Compared to baseline, trained PD patients experienced a significant increase in their olfactory function, which was observed for the Sniffin' Sticks test score and for thresholds for the odors used in the training process. Olfactory function was unchanged in PD patients who did not perform olfactory training. CONCLUSION: The present results indicate that olfactory training may increase olfactory sensitivity in PD patients.

  2. The role of dopamine in Drosophila larval classical olfactory conditioning.

    Directory of Open Access Journals (Sweden)

    Mareike Selcho

    Full Text Available Learning and memory is not an attribute of higher animals. Even Drosophila larvae are able to form and recall an association of a given odor with an aversive or appetitive gustatory reinforcer. As the Drosophila larva has turned into a particularly simple model for studying odor processing, a detailed neuronal and functional map of the olfactory pathway is available up to the third order neurons in the mushroom bodies. At this point, a convergence of olfactory processing and gustatory reinforcement is suggested to underlie associative memory formation. The dopaminergic system was shown to be involved in mammalian and insect olfactory conditioning. To analyze the anatomy and function of the larval dopaminergic system, we first characterize dopaminergic neurons immunohistochemically up to the single cell level and subsequent test for the effects of distortions in the dopamine system upon aversive (odor-salt as well as appetitive (odor-sugar associative learning. Single cell analysis suggests that dopaminergic neurons do not directly connect gustatory input in the larval suboesophageal ganglion to olfactory information in the mushroom bodies. However, a number of dopaminergic neurons innervate different regions of the brain, including protocerebra, mushroom bodies and suboesophageal ganglion. We found that dopamine receptors are highly enriched in the mushroom bodies and that aversive and appetitive olfactory learning is strongly impaired in dopamine receptor mutants. Genetically interfering with dopaminergic signaling supports this finding, although our data do not exclude on naïve odor and sugar preferences of the larvae. Our data suggest that dopaminergic neurons provide input to different brain regions including protocerebra, suboesophageal ganglion and mushroom bodies by more than one route. We therefore propose that different types of dopaminergic neurons might be involved in different types of signaling necessary for aversive and appetitive

  3. Olfactory interference during inhibitory backward pairing in honey bees.

    Directory of Open Access Journals (Sweden)

    Matthieu Dacher

    Full Text Available Restrained worker honey bees are a valuable model for studying the behavioral and neural bases of olfactory plasticity. The proboscis extension response (PER; the proboscis is the mouthpart of honey bees is released in response to sucrose stimulation. If sucrose stimulation is preceded one or a few times by an odor (forward pairing, the bee will form a memory for this association, and subsequent presentations of the odor alone are sufficient to elicit the PER. However, backward pairing between the two stimuli (sucrose, then odor has not been studied to any great extent in bees, although the vertebrate literature indicates that it elicits a form of inhibitory plasticity.If hungry bees are fed with sucrose, they will release a long lasting PER; however, this PER can be interrupted if an odor is presented 15 seconds (but not 7 or 30 seconds after the sucrose (backward pairing. We refer to this previously unreported process as olfactory interference. Bees receiving this 15 second backward pairing show reduced performance after a subsequent single forward pairing (excitatory conditioning trial. Analysis of the results supported a relationship between olfactory interference and a form of backward pairing-induced inhibitory learning/memory. Injecting the drug cimetidine into the deutocerebrum impaired olfactory interference.Olfactory interference depends on the associative link between odor and PER, rather than between odor and sucrose. Furthermore, pairing an odor with sucrose can lead either to association of this odor to PER or to the inhibition of PER by this odor. Olfactory interference may provide insight into processes that gate how excitatory and inhibitory memories for odor-PER associations are formed.

  4. Telencephalic organization of the olfactory system in homing pigeons (Columba livia).

    Science.gov (United States)

    Patzke, N; Manns, M; Güntürkün, O

    2011-10-27

    Pigeons use olfactory cues to navigate over unfamiliar areas, and any impairment of the olfactory system generates remarkable reduction of homing performance. Lesion and deprivation studies suggest a critical involvement of the right nostril and thus, the right olfactory bulb (OB) and the left piriform cortex (CPi) for initial orientation. This functional pattern suggests that OB and CPi are asymmetrically connected with a stronger projection from the right OB to the left CPi. However, the structural organization of the olfactory system is not unequivocally clarified yet. Thus, we re-analyzed the system by antero- and retrograde tract tracing with biotinylated dextran amine and choleratoxin subunit B, and we especially evaluated quantitative differences in the number of cells in the OB innervating the left and right CPi. Our anterograde tracing data verified a strong bilateral input to the CPi, and the prepiriform cortex (CPP), as well as small projections to the ipsilateral medial septum and the dorsolateral corticoid area and the nucleus taeniae of the amygdala in both hemispheres. Apart from the bilateral bulbar afferents, CPi in turn receives unequivocal input from the ipsilateral CPP, hyperpallium densocellulare, dorsal arcopallium, and from a cluster of cells located within the frontolateral nidopallium. Thus, an indirect connection between OB and CPi is only mediated by the CPP. For quantitative analysis of bulbar input to the CPi, we counted the number of ipsi- and contralaterally projecting neurons located in the OB after injections into the left or right CPi. Retrogradely labeled cells were found bilaterally in the OB with a higher number of ipsilaterally located cells. The bilaterality index did not differ after left- or right-sided CPi injections indicating that the functional lateralization of the olfactory system is not simply based on differences in the number of projecting axons of the major processing stream. Copyright © 2011 IBRO. Published by

  5. Activity-dependent expression of miR-132 regulates immediate-early gene induction during olfactory learning in the greater short-nosed fruit bat, Cynopterus sphinx.

    Science.gov (United States)

    Mukilan, Murugan; Ragu Varman, Durairaj; Sudhakar, Sivasubramaniam; Rajan, Koilmani Emmanuvel

    2015-04-01

    The activity-dependent expression of immediate-early genes (IEGs) and microRNA (miR)-132 has been implicated in synaptic plasticity and the formation of long-term memory (LTM). In the present study, we show that olfactory training induces the expression of IEGs (EGR-1, C-fos, C-jun) and miR-132 at similar time scale in olfactory bulb (OB) of Cynopterus sphinx. We examined the role of miR-132 in the OB using antisense oligodeoxynucleotide (AS-ODN) and demonstrated that a local infusion of AS-ODN in the OB 2h prior to training impaired olfactory memory formation in C. sphinx. However, the infusion of AS-ODN post-training did not cause a deficit in memory formation. Furthermore, the inhibition of miR-132 reduced the olfactory training-induced expression of IEGs and post synaptic density protein-95 (PSD-95) in the OB. Additionally, we show that miR-132 regulates the activation of calcium/calmodulin-dependent protein kinase-II (CaMKII) and cAMP response element binding protein (CREB), possibly through miR-148a. These data suggest that olfactory training induces the expression of miR-132 and IEGs, which in turn activates post-synaptic proteins that regulate olfactory memory formation. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Phytochemical analysis of Cyrtanthus obliquus bulbs from the ...

    African Journals Online (AJOL)

    Proff.Adewunmi

    dihydroxy-lanosta-8-ene was also isolated from the bulbs. The ... Fresh bulbs from C. obliquus were purchased at the Berea market in Durban and identified by a curator from the School of Biological and. Conservation Sciences, UKZN, Westville ...

  7. New treatment of vertigo caused by jugular bulb abnormalities.

    Science.gov (United States)

    Hitier, Martin; Barbier, Charlotte; Marie-Aude, Thenint; Moreau, Sylvain; Courtheoux, Patrick; Patron, Vincent

    2014-08-01

    Jugular bulb abnormalities can induce tinnitus, hearing loss, or vertigo. Vertigo can be very disabling and may need surgical treatments with risk of hearing loss, major bleeding or facial palsy. Hence, we have developed a new treatment for vertigo caused by jugular bulb anomalies, using an endovascular technique. Three patients presented with severe vertigos mostly induced by high venous pressure. One patient showed downbeat vertical nystagmus during the Valsalva maneuver. The temporal-bone computed tomography scan showed a high rising jugular bulb or a jugular bulb diverticulum with dehiscence and compression of the vestibular aqueduct in all cases. We plugged the upper part of the bulb with coils, and we used a stent to maintain the coils and preserving the venous permeability. After 12- to 24-month follow-up, those patients experienced no more vertigo, allowing return to work. The 3-month arteriographs showed good permeability of the sigmoid sinus and jugular bulb through the stent, with complete obstruction of the upper part of the bulb in all cases. Disabling vertigo induced by jugular bulb abnormalities can be effectively treated by an endovascular technique. This technique is minimally invasive with a probable greater benefit/risk ratio compare with surgery. © The Author(s) 2013.

  8. RESPONSE OF ONION (Allium cepa L.) BULB YIELD TO DAY ...

    African Journals Online (AJOL)

    PROF EKWUEME

    2012-06-17

    Jun 17, 2012 ... to the significance of onion bulbs in Nigeria, research efforts at the National Horticultural ... of Jos, Plateau State, Nigeria. O. A. T. Namo, Department of Plant Science and Technology, University of Jos, Plateau State, Nigeria ... plants to a source of light (two mercury solar light fluorescence bulbs of 150 watts ...

  9. The "Brightness Rules" Alternative Conception for Light Bulb Circuits

    Science.gov (United States)

    Bryan, Joel A.; Stuessy, Carol

    2006-01-01

    An alternative conception for the observed differences in light bulb brightness was revealed during an unguided inquiry investigation in which prospective elementary teachers placed identical bulbs in series, parallel, and combination direct current circuits. Classroom observations, document analyses, and video and audio transcriptions led to the…

  10. Exogenous ethylene inhibits sprout growth in onion bulbs.

    Science.gov (United States)

    Bufler, Gebhard

    2009-01-01

    Exogenous ethylene has recently gained commercial interest as a sprouting inhibitor of onion bulbs. The role of ethylene in dormancy and sprouting of onions, however, is not known. A cultivar (Allium cepa 'Copra') with a true period of dormancy was used. Dormant and sprouting states of onion bulbs were treated with supposedly saturating doses of ethylene or with the ethylene-action inhibitor 1-methylcyclopropene (1-MCP). Initial sprouting was determined during storage at 18 degrees C by monitoring leaf blade elongation in a specific size class of leaf sheaths. Changes in ATP content and sucrose synthase activity in the sprout leaves, indicators of the sprouting state, were determined. CO(2) and ethylene production of onion bulbs during storage were recorded. Exogenous ethylene suppressed sprout growth of both dormant and already sprouting onion bulbs by inhibiting leaf blade elongation. In contrast to this growth-inhibiting effect, ethylene stimulated CO(2) production by the bulbs about 2-fold. The duration of dormancy was not significantly affected by exogenous ethylene. However, treatment of dormant bulbs with 1-MCP caused premature sprouting. Exogenous ethylene proved to be a powerful inhibitor of sprout growth in onion bulbs. The dormancy breaking effect of 1-MCP indicates a regulatory role of endogenous ethylene in onion bulb dormancy.

  11. Defining sale ethylene for long term storage of tulip bulbs

    NARCIS (Netherlands)

    Wild, de H.P.J.; Peppelenbos, H.W.; Dijkstra, M.H.G.E.; Gude, H.

    2002-01-01

    The maximum ethylene level that can be permitted in storage rooms, without causing damage to tulip bulbs, is not exactly known. Therefore, a zero-tolerance for the presence of ethylene during storage of tulip bulbs is common practice. This results in excessive ventilation and coherent large energy

  12. Conservation of garlic bulbs (Allium sativum L. ) by gamma irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, J.; Arranz, T.

    1979-01-01

    The effect of different doses of gamma radiation (from 5 to 30 krad) on the conservation of garlic bulbs during a 12 months period is studied. Irradiations were made at three different times and the best results were obtained with the treatment given during the two months following harvest. During this period, 5 krad are enough to inhibit garlic bulbs sprouting.

  13. Heat pump applications in Dutch flower bulb farms

    NARCIS (Netherlands)

    Wit, J.B. de

    1999-01-01

    Increasing numbers of flower bulb fanns in the Netherlands are using heat pumps for conditioning bulbs. The main advantage of the (electric) heat pump is that it combines all conditioning steps (drying, cooling and heating) in one device. Another advantage is that it makes process control simple and

  14. Conservation of garlic bulbs (allium sativum L.) by gamma irradiation

    International Nuclear Information System (INIS)

    Fernandez, J.; Arranz, T.

    1979-01-01

    The effect of different doses of gamma radiation (from 5 to 30 krad) on the conservation of garlic bulbs during a 12 months period is studied. Irradiations were made at three different times and the best results were obtained with the treatment given during the two months following harvest. During this period, 5krad are enough to inhibit garlic bulbs sprouting. (author)

  15. Identification of the Ulex europaeus agglutinin-I-binding protein as a unique glycoform of the neural cell adhesion molecule in the olfactory sensory axons of adults rats.

    Science.gov (United States)

    Pestean, A; Krizbai, I; Böttcher, H; Párducz, A; Joó, F; Wolff, J R

    1995-08-04

    Histochemical localization of two lectins, Ulex europaeus agglutinin-I (UEA-I) and Tetragonolobus purpureus (TPA), was studied in the olfactory bulb of adult rats. In contrast to TPA, UEA-I detected a fucosylated glycoprotein that is only present in the surface membranes of olfactory sensory cells including the whole course of their neurites up to the final arborization in glomeruli. Immunoblotting revealed that UEA-I binds specifically to a protein of 205 kDa, while TPA stains several other glycoproteins. Affinity chromatography with the use of a UEA-I column identified the 205 kDa protein as a glycoform of neural cell adhesion molecule (N-CAM), specific for the rat olfactory sensory nerves.

  16. Olfactory memory in the old and very old: relations to episodic and semantic memory and APOE genotype.

    Science.gov (United States)

    Larsson, Maria; Hedner, Margareta; Papenberg, Goran; Seubert, Janina; Bäckman, Lars; Laukka, Erika J

    2016-02-01

    The neuroanatomical organization that underlies olfactory memory is different from that of other memory types. The present work examines olfactory memory in an elderly population-based sample (Swedish National Study on Aging and Care in Kungsholmen) aged 60-100 years (n = 2280). We used structural equation modeling to investigate whether olfactory memory in old age is best conceptualized as a distinct category, differentiated from episodic and semantic memory. Further, potential olfactory dedifferentiation and genetic associations (APOE) to olfactory function in late senescence were investigated. Results are in support of a 3-factor solution where olfactory memory, as indexed by episodic odor recognition and odor identification, is modeled separately from episodic and semantic memory for visual and verbal information. Increasing age was associated with poorer olfactory memory performance, and observed age-related deficits were further exacerbated for carriers of the APOE ε4 allele; these effects tended to be larger for olfactory memory compared to episodic and semantic memory pertaining to other sensory systems (vision, auditory). Finally, stronger correlations between olfactory and episodic memory, indicating dedifferentiation, were observed in the older age groups. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Numerical simulation of draft tube flow of a bulb turbine

    Energy Technology Data Exchange (ETDEWEB)

    Coelho, J.G. [Federal University of Triangulo Mineiro, Institute of Technological and Exact Sciences, Avenida Doutor Randolfo Borges Junior, 1250 – Uberaba – MG (Brazil); Brasil, A.C.P. Jr. [University of Brasilia, Department of Mechanical Engineering, Campus Darcy Ribeiro, Brasilia – DF (Brazil)

    2013-07-01

    In this work a numerical study of draft tube of a bulb hydraulic turbine is presented, where a new geometry is proposed. This new proposal of draft tube has the unaffected ratio area, a great reduction in his length and approximately the same efficiency of the draft tube conventionally used. The numerical simulations were obtained in commercial software of calculation of flow (CFX-14), using the turbulence model SST, that allows a description of the field fluid dynamic near to the wall. The simulation strategy has an intention of identifying the stall of the boundary layer precisely limits near to the wall and recirculations in the central part, once those are the great causes of the decrease of efficiency of a draft tube. Finally, it is obtained qualitative and quantitative results about the flow in draft tubes.

  18. Hepatoprotective Activity of Easter Lily (Lilium longiflorum Thunb.) Bulb Extracts.

    Science.gov (United States)

    Tang, Wenping; Munafo, John P; Palatini, Kimberly; Esposito, Debora; Huang, Mou-Tuan; Komarnytsky, Slavko; Ho, Chi-Tang; Gianfagna, Thomas J

    2015-11-11

    The hepatoprotective activities of two different extracts, a hydroethanolic crude bulb extract (CB) and a steroidal glycoside-rich 1-butanol extract (BuOH), prepared from the bulbs of Easter lily (Lilium longiflorum Thunb.), were evaluated in a 24 week study in the female KK.Cg-A(y)/J Type 2 diabetic mouse model. Animals were divided into six groups (n = 16): control mice received Easter lily bulb extract-free drinking water together with a low- or high-fat diet (diabetic control); drinking water for the remaining groups was supplemented with CB extract (1%), BuOH extract (0.1 or 0.2%), and reference drug Metformin (0.001%), together with a high-fat diet. Both CB and BuOH extract treatment groups exhibited significantly improved liver function based on comparisons of triglycerides [diabetic 219 ± 34 mg/dL, CB 131 ± 27 mg/dL, BuOH(0.2%) 114 ± 35 mg/dL], CB total cholesterol (TC) (diabetic 196 ± 12 mg/dL, CB 159 ± 5 mg/dL), average liver mass [diabetic 2.96 ± 0.13 g, CB 2.58 ± 0.08 g, BuOH(0.1%) 2.48 ± 0.13 g], alanine transferase [diabetic 74 ± 5 units/L, CB 25 ± 1 units/L, BuOH(0.1%) 45 ± 1 units/L], and histological examinations. Glucose metabolism was improved only in CB, which was confirmed by oral glucose tolerance tests (OGTT) in diet-induced obese C57BL/6J mice exposed to CB extract. These data suggest that steroidal glycosides 1-5 might play a role in the hepatoprotective activity of the BuOH extracts, while the results of the TC measurements and OGTT study indicate that other constituents present in the CB extract are responsible for its hypocholesterolemic and hypoglycemic activity.

  19. Odor-evoked inhibition of olfactory sensory neurons drives olfactory perception in Drosophila.

    Science.gov (United States)

    Cao, Li-Hui; Yang, Dong; Wu, Wei; Zeng, Xiankun; Jing, Bi-Yang; Li, Meng-Tong; Qin, Shanshan; Tang, Chao; Tu, Yuhai; Luo, Dong-Gen

    2017-11-07

    Inhibitory response occurs throughout the nervous system, including the peripheral olfactory system. While odor-evoked excitation in peripheral olfactory cells is known to encode odor information, the molecular mechanism and functional roles of odor-evoked inhibition remain largely unknown. Here, we examined Drosophila olfactory sensory neurons and found that inhibitory odors triggered outward receptor currents by reducing the constitutive activities of odorant receptors, inhibiting the basal spike firing in olfactory sensory neurons. Remarkably, this odor-evoked inhibition of olfactory sensory neurons elicited by itself a full range of olfactory behaviors from attraction to avoidance, as did odor-evoked olfactory sensory neuron excitation. These results indicated that peripheral inhibition is comparable to excitation in encoding sensory signals rather than merely regulating excitation. Furthermore, we demonstrated that a bidirectional code with both odor-evoked inhibition and excitation in single olfactory sensory neurons increases the odor-coding capacity, providing a means of efficient sensory encoding.

  20. Freezing Injury in Onion Bulb Cells

    Science.gov (United States)

    Palta, Jiwan P.; Levitt, Jacob; Stadelmann, Eduard J.

    1977-01-01

    Onion (Allium cepa L.) bulbs were frozen to −4 and −11 C and kept frozen for up to 12 days. After slow thawing, a 2.5-cm square from a bulb scale was transferred to 25 ml deionized H2O. After shaking for standard times, measurements were made on the effusate and on the effused cells. The results obtained were as follows. Even when the scale tissue was completely infiltrated, and when up to 85% of the ions had diffused out, all of the cells were still alive, as revealed by cytoplasmic streaming and ability to plasmolyze. The osmotic concentration of the cell sap, as measured plasmolytically, decreased in parallel to the rise in conductivity of the effusate. The K+ content of the effusate, plus its assumed counterion, accounted for only 20% of the total solutes, but for 100% of the conductivity. A large part of the nonelectrolytes in the remaining 80% of the solutes was sugars. The increased cell injury and infiltration in the −11 C treatment, relative to the −4 C and control (unfrozen) treatments, were paralleled by increases in conductivity, K+ content, sugar content, and pH of the effusate. In spite of the 100% infiltration of the tissue and the large increase in conductivity of the effusate following freezing, no increase in permeability of the cells to water could be detected. The above observations may indicate that freezing or thawing involves a disruption of the active transport system before the cells reveal any injury microscopically. PMID:16660100

  1. Transplantation of olfactory ensheathing cells as adjunct cell therapy for peripheral nerve injury.

    Science.gov (United States)

    Radtke, Christine; Wewetzer, Konstantin; Reimers, Kerstin; Vogt, Peter M

    2011-01-01

    Traumatic events, such as work place trauma or motor vehicle accident violence, result in a significant number of severe peripheral nerve lesions, including nerve crush and nerve disruption defects. Transplantation of myelin-forming cells, such as Schwann cells (SCs) or olfactory ensheathing cells (OECs), may be beneficial to the regenerative process because the applied cells could mediate neurotrophic and neuroprotective effects by secretion of chemokines. Moreover, myelin-forming cells are capable of bridging the repair site by establishing an environment permissive to axonal regeneration. The cell types that are subject to intense investigation include SCs and OECs either derived from the olfactory bulb or the olfactory mucosa, stromal cells from bone marrow (mesenchymal stem cells, MSCs), and adipose tissue-derived cells. OECs reside in the peripheral and central nervous system and have been suggested to display unique regenerative properties. However, so far OECs were mainly used in experimental studies to foster central regeneration and it was not until recently that their regeneration-promoting activity for the peripheral nervous system was recognized. In the present review, we summarize recent experimental evidence regarding the regenerative effects of OECs applied to the peripheral nervous system that may be relevant to design novel autologous cell transplantation therapies. © 2011 Cognizant Comm. Corp.

  2. Vomeronasal versus olfactory epithelium: is there a cellular basis for human vomeronasal perception?

    Science.gov (United States)

    Witt, Martin; Hummel, Thomas

    2006-01-01

    The vomeronasal organ (VNO) constitutes an accessory olfactory organ that receives chemical stimuli, pheromones, which elicit behavioral, reproductive, or neuroendocrine responses among individuals of the same species. In many macrosmatic animals, the morphological substrate constitutes a separate organ system consisting of a vomeronasal duct (ductus vomeronasalis, VND), equipped with chemosensory cells, and a vomeronasal nerve (nervus vomeronasalis, VNN) conducting information into the accessory olfactory bulb (AOB) in the central nervous system (CNS). Recent data require that the long-accepted dual functionality of a main olfactory system and the VNO be reexamined, since all species without a VNO are nevertheless sexually active, and species possessing a VNO also can sense other than "vomeronasal" stimuli via the vomeronasal epithelium (VNE). The human case constitutes a borderline situation, as its embryonic VNO anlage exerts a developmental track common to most macrosmatics, but later typical structures such as the VNN, AOB, and probably most of the chemoreceptor cells within the still existent VND are lost. This review also presents recent information on the VND including immunohistochemical expression of neuronal markers, intermediate filaments, lectins, integrins, caveolin, CD44, and aquaporins. Further, we will address the issue of human pheromone candidates.

  3. Coincidence of pheromone and plant odor leads to sensory plasticity in the heliothine olfactory system.

    Directory of Open Access Journals (Sweden)

    Elena Ian

    Full Text Available Male moths possess a highly specialized olfactory system comprised of two segregated sub-arrangements dedicated to processing information about plant odors and pheromones, respectively. Communication between these two sub-systems has been described at the peripheral level, but relatively little is known about putative interactions at subsequent synaptic relays. The male moth faces the challenge of seeking out the conspecific female in a highly dynamic odor world. The female-produced pheromone blend, which is a limited resource serving as guidance for the male, will reach his antennae in intermittent pockets of odor filaments mixed with volatiles from various plants. In the present study we performed calcium imaging for measuring odor-evoked responses in the uni-glomerular antennal-lobe projection neurons (analog to mitral cells in the vertebrate olfactory bulb of Helicoverpa armigera. In order to investigate putative interactions between the two sub-systems tuned to plant volatiles and pheromones, respectively, we performed repeated stimulations with a selection of biologically relevant odors. We found that paired stimulation with a plant odor and the pheromone led to suppressed responses in both sub-systems as compared to those evoked during initial stimulation including application of each odor stimulus alone. The fact that the suppression persisted also after pairing, indicates the existence of a Hebbian-like plasticity in the primary olfactory center established by temporal pairing of the two odor stimulation categories.

  4. SLEEP AND OLFACTORY CORTICAL PLASTICITY

    Directory of Open Access Journals (Sweden)

    Dylan eBarnes

    2014-04-01

    Full Text Available In many systems, sleep plays a vital role in memory consolidation and synaptic homeostasis. These processes together help store information of biological significance and reset synaptic circuits to facilitate acquisition of information in the future. In this review, we describe recent evidence of sleep-dependent changes in olfactory system structure and function which contribute to odor memory and perception. During slow-wave sleep, the piriform cortex becomes hypo-responsive to odor stimulation and instead displays sharp-wave activity similar to that observed within the hippocampal formation. Furthermore, the functional connectivity between the piriform cortex and other cortical and limbic regions is enhanced during slow-wave sleep compared to waking. This combination of conditions may allow odor memory consolidation to occur during a state of reduced external interference and facilitate association of odor memories with stored hedonic and contextual cues. Evidence consistent with sleep-dependent odor replay within olfactory cortical circuits is presented. These data suggest that both the strength and precision of odor memories is sleep-dependent. The work further emphasizes the critical role of synaptic plasticity and memory in not only odor memory but also basic odor perception. The work also suggests a possible link between sleep disturbances that are frequently co-morbid with a wide range of pathologies including Alzheimer’s disease, schizophrenia and depression and the known olfactory impairments associated with those disorders.

  5. Draft tube flow phenomena across the bulb turbine hill chart

    International Nuclear Information System (INIS)

    Duquesne, P; Fraser, R; Maciel, Y; Aeschlimann, V; Deschênes, C

    2014-01-01

    In the framework of the BulbT project launched by the Consortium on Hydraulic Machines and the LAMH (Hydraulic Machine Laboratory of Laval University) in 2011, an intensive campaign to identify flow phenomena in the draft tube of a model bulb turbine has been done. A special focus was put on the draft tube component since it has a particular importance for recuperation in low head turbines. Particular operating points were chosen to analyse flow phenomena in this component. For each of these operating points, power, efficiency and pressure were measured following the IEC 60193 standard. Visualizations, unsteady wall pressure and efficiency measurements were performed in this component. The unsteady wall pressure was monitored at seven locations in the draft tube. The frequency content of each pressure signal was analyzed in order to characterize the flow phenomena across the efficiency hill chart. Visualizations were recorded with a high speed camera using tufts and cavitation bubbles as markers. The predominant detected phenomena were mapped and categorized in relation to the efficiency hill charts obtained for three runner blade openings. At partial load, the vortex rope was detected and characterized. An inflection in the partial load efficiency curves was found to be related to complex vortex rope instabilities. For overload conditions, the efficiency curves present a sharp drop after the best efficiency point, corresponding to an inflection on the power curves. This break off is more severe towards the highest blade openings. It is correlated to a flow separation at the wall of the draft tube. Also, due to the separation occurring in these conditions, a hysteresis effect was observed on the efficiency curves

  6. Fabrication of Closed Hollow Bulb Obturator Using Thermoplastic Resin Material

    Directory of Open Access Journals (Sweden)

    Bidhan Shrestha

    2015-01-01

    Full Text Available Purpose. Closed hollow bulb obturators are used for the rehabilitation of postmaxillectomy patients. However, the time consuming process, complexity of fabrication, water leakage, and discoloration are notable disadvantages of this technique. This paper describes a clinical report of fabricating closed hollow bulb obturator using a single flask and one time processing method for an acquired maxillary defect. Hard thermoplastic resin sheet has been used for the fabrication of hollow bulb part of the obturator. Method. After fabrication of master cast conventionally, bulb and lid part of the defect were formed separately and joined by autopolymerizing acrylic resin to form one sized smaller hollow body. During packing procedure, the defect area was loaded with heat polymerizing acrylic resin and then previously fabricated smaller hollow body was adapted over it. The whole area was then loaded with heat cure acrylic. Further processes were carried out conventionally. Conclusion. This technique uses single flask which reduces laboratory time and makes the procedure simple. The thickness of hollow bulb can be controlled and light weight closed hollow bulb prosthesis can be fabricated. It also minimizes the disadvantages of closed hollow bulb obturator such as water leakage, bacterial infection, and discoloration.

  7. Is TrpM5 a reliable marker for chemosensory cells? Multiple types of microvillous cells in the main olfactory epithelium of mice

    Directory of Open Access Journals (Sweden)

    Finger Thomas E

    2008-12-01

    Full Text Available Abstract Background In the past, ciliated receptor neurons, basal cells, and supporting cells were considered the principal components of the main olfactory epithelium. Several studies reported the presence of microvillous cells but their function is unknown. A recent report showed cells in the main olfactory epithelium that express the transient receptor potential channel TrpM5 claiming that these cells are chemosensory and that TrpM5 is an intrinsic signaling component of mammalian chemosensory organs. We asked whether the TrpM5-positive cells in the olfactory epithelium are microvillous and whether they belong to a chemosensory system, i.e. are olfactory neurons or trigeminally-innervated solitary chemosensory cells. Results We investigated the main olfactory epithelium of mice at the light and electron microscopic level and describe several subpopulations of microvillous cells. The ultrastructure of the microvillous cells reveals at least three morphologically different types two of which express the TrpM5 channel. None of these cells have an axon that projects to the olfactory bulb. Tests with a large panel of cell markers indicate that the TrpM5-positive cells are not sensory since they express neither neuronal markers nor are contacted by trigeminal nerve fibers. Conclusion We conclude that TrpM5 is not a reliable marker for chemosensory cells. The TrpM5-positive cells of the olfactory epithelium are microvillous and may be chemoresponsive albeit not part of the sensory apparatus. Activity of these microvillous cells may however influence functionality of local elements of the olfactory system.

  8. Olfactory memories are intensity specific in larval Drosophila.

    Science.gov (United States)

    Mishra, Dushyant; Chen, Yi-Chun; Yarali, Ayse; Oguz, Tuba; Gerber, Bertram

    2013-05-01

    Learning can rely on stimulus quality, stimulus intensity, or a combination of these. Regarding olfaction, the coding of odour quality is often proposed to be combinatorial along the olfactory pathway, and working hypotheses are available concerning short-term associative memory trace formation of odour quality. However, it is less clear how odour intensity is coded, and whether olfactory memory traces include information about the intensity of the learnt odour. Using odour-sugar associative conditioning in larval Drosophila, we first describe the dose-effect curves of learnability across odour intensities for four different odours (n-amyl acetate, 3-octanol, 1-octen-3-ol and benzaldehyde). We then chose odour intensities such that larvae were trained at an intermediate odour intensity, but were tested for retention with either that trained intermediate odour intensity, or with respectively higher or lower intensities. We observed a specificity of retention for the trained intensity for all four odours used. This adds to the appreciation of the richness in 'content' of olfactory short-term memory traces, even in a system as simple as larval Drosophila, and to define the demands on computational models of associative olfactory memory trace formation. We suggest two kinds of circuit architecture that have the potential to accommodate intensity learning, and discuss how they may be implemented in the insect brain.

  9. Sensory quality of irradiated onion and garlic bulbs

    International Nuclear Information System (INIS)

    Curzio, O.A.; Urioste, A.M.

    1994-01-01

    The radioinhibition process has shown to prolong shelf-life of ''Valenciana sintetica 14'' onion variety and ''Colorado'' garlic variety. Sensory attributes of the irradiated bulbs were tested monthly by trained judges during extended storage in warehouse conditions (6-32C, R.H. 40-50%). The sensory properties observed were external and internal appearance, firmness and odor. The irradiated bulbs were judged to be superior in quality with respect to internal and external appearance (p 0.01) and firmness (p 0.01), after 180 days postharvest. The irradiated bulbs showed no difference in odor (p 0.05), when compared to unirradiated ones, through the storage period

  10. Oxytocin administration selectively improves olfactory detection thresholds for lyral in patients with schizophrenia.

    Science.gov (United States)

    Woolley, J D; Lam, O; Chuang, B; Ford, J M; Mathalon, D H; Vinogradov, S

    2015-03-01

    Olfaction plays an important role in mammalian social behavior. Olfactory deficits are common in schizophrenia and correlate with negative symptoms and low social drive. Despite their prominence and possible clinical relevance, little is understood about the pathological mechanisms underlying olfactory deficits in schizophrenia and there are currently no effective treatments for these deficits. The prosocial neuropeptide oxytocin may affect the olfactory system when administered intranasally to humans and there is growing interest in its therapeutic potential in schizophrenia. To examine this model, we administered 40IU of oxytocin and placebo intranasally to 31 patients with a schizophrenia spectrum illness and 34 age-matched healthy control participants in a randomized, double-blind, placebo-controlled, cross-over study. On each test day, participants completed an olfactory detection threshold test for two different odors: (1) lyral, a synthetic fragrance compound for which patients with schizophrenia have specific olfactory detection threshold deficits, possibly related to decreased cyclic adenosine 3',5'-monophosphate (cAMP) signaling; and (2) anise, a compound for which olfactory detection thresholds change with menstrual cycle phase in women. On the placebo test day, patients with schizophrenia did not significantly differ from healthy controls in detection of either odor. We found that oxytocin administration significantly and selectively improved olfactory detection thresholds for lyral but not for anise in patients with schizophrenia. In contrast, oxytocin had no effect on detection of either odor in healthy controls. Our data indicate that oxytocin administration may ameliorate olfactory deficits in schizophrenia and suggest the effects of intranasal oxytocin may extend to influencing the olfactory system. Given that oxytocin has been found to increase cAMP signaling in vitro a possible mechanism for these effects is discussed. Published by Elsevier Ltd.

  11. Induction of associative olfactory memory by targeted activation of single olfactory neurons in Drosophila larvae.

    Science.gov (United States)

    Honda, Takato; Lee, Chi-Yu; Yoshida-Kasikawa, Maki; Honjo, Ken; Furukubo-Tokunaga, Katsuo

    2014-04-25

    It has been postulated that associative memory is formed by at least two sets of external stimuli, CS and US, that are transmitted to the memory centers by distinctive conversing pathways. However, whether associative memory can be induced by the activation of only the olfactory CS and a biogenic amine-mediated US pathways remains to be elucidated. In this study, we substituted the reward signals with dTrpA1-mediated thermogenetic activation of octopaminergic neurons and the odor signals by ChR2-mediated optical activation of a specific class of olfactory neurons. We show that targeted activation of the olfactory receptor and the octopaminergic neurons is indeed sufficient for the formation of associative olfactory memory in the larval brain. We also show that targeted stimulation of only a single type of olfactory receptor neurons is sufficient to induce olfactory memory that is indistinguishable from natural memory induced by the activation of multiple olfactory receptor neurons.

  12. Biological complexity and adaptability of simple mammalian olfactory memory systems.

    Science.gov (United States)

    Brennan, P; Keverne, E B

    2015-03-01

    Chemosensory systems play vital roles in the lives of most mammals, including the detection and identification of predators, as well as sex and reproductive status and the identification of individual conspecifics. All of these capabilities require a process of recognition involving a combination of innate (kairomonal/pheromonal) and learned responses. Across very different phylogenies, the mechanisms for pheromonal and odour learning have much in common. They are frequently associated with plasticity of GABA-ergic feedback at the initial level of processing the chemosensory information, which enhances its pattern separation capability. Association of odourant features into an odour object primarily involves anterior piriform cortex for non-social odours. However, the medial amygdala appears to be involved in both the recognition of social odours and their association with chemosensory information sensed by the vomeronasal system. Unusually not only the sensory neurons themselves, but also the GABA-ergic interneurons in the olfactory bulb are continually being replaced, with implications for the induction and maintenance of learned chemosensory responses. Crown Copyright © 2014. Published by Elsevier Ltd. All rights reserved.

  13. New Penicillium species associated with bulbs and root vegetables

    DEFF Research Database (Denmark)

    Overy, David Patrick; Frisvad, Jens Christian

    2003-01-01

    Taxa of the Penicillium series Corymbifera are known for their strongly fasciculate growth and association with the rhizosphere of vegetables and flower bulbs. Using micromorphology, colony characteristics on various media and chemotaxonomic profiling, P. albocoremium sensu stricto and two new...

  14. Hydroponic technology for lily flowers and bulbs production using ...

    African Journals Online (AJOL)

    Aghomotsegin

    2015-07-22

    EC) and .... rock wool cubes as growing medium; the tang measures were 112 ... and weight of bulb roots, stem roots, bulblets roots per plant were ... The statistical analysis system (SAS, 2012) was used to effect ..... In vitro cell.

  15. Posttraining ablation of adult-generated olfactory granule cells degrades odor-reward memories.

    Science.gov (United States)

    Arruda-Carvalho, Maithe; Akers, Katherine G; Guskjolen, Axel; Sakaguchi, Masanori; Josselyn, Sheena A; Frankland, Paul W

    2014-11-19

    Proliferation of neural progenitor cells in the subventricular zone leads to the continuous generation of new olfactory granule cells (OGCs) throughout life. These cells synaptically integrate into olfactory bulb circuits after ∼2 weeks and transiently exhibit heightened plasticity and responses to novel odors. Although these observations suggest that adult-generated OGCs play important roles in olfactory-related memories, global suppression of olfactory neurogenesis does not typically prevent the formation of odor-reward memories, perhaps because residual OGCs can compensate. Here, we used a transgenic strategy to selectively ablate large numbers of adult-generated OGCs either before or after learning in mice. Consistent with previous studies, pretraining ablation of adult-generated OGCs did not prevent the formation of an odor-reward memory, presumably because existing OGCs can support memory formation in their absence. However, ablation of a similar cohort of adult-generated OGCs after training impaired subsequent memory expression, indicating that if these cells are available at the time of training, they play an essential role in subsequent expression of odor-reward memories. Memory impairment was associated with the loss of adult-generated OGCs that were >10 d in age and did not depend on the developmental stage in which they were generated, suggesting that, once sufficiently mature, OGCs generated during juvenility and adulthood play similar roles in the expression of odor-reward memories. Finally, ablation of adult-generated OGCs 1 month after training did not produce amnesia, indicating that adult-generated OGCs play a time-limited role in the expression of odor-reward memories. Copyright © 2014 the authors 0270-6474/14/3415793-11$15.00/0.

  16. Degeneration of the olfactory guanylyl cyclase D gene during primate evolution.

    Directory of Open Access Journals (Sweden)

    Janet M Young

    2007-09-01

    Full Text Available The mammalian olfactory system consists of several subsystems that detect specific sets of chemical cues and underlie a variety of behavioral responses. Within the main olfactory epithelium at least three distinct types of chemosensory neurons can be defined by their expression of unique sets of signal transduction components. In rodents, one set of neurons expresses the olfactory-specific guanylyl cyclase (GC-D gene (Gucy2d, guanylyl cyclase 2d and other cell-type specific molecules. GC-D-positive neurons project their axons to a small group of atypical "necklace" glomeruli in the olfactory bulb, some of which are activated in response to suckling in neonatal rodents and to atmospheric CO2 in adult mice. Because GC-D is a pseudogene in humans, signaling through this system appears to have been lost at some point in primate evolution.Here we used a combination of bioinformatic analysis of trace-archive and genome-assembly data and sequencing of PCR-amplified genomic DNA to determine when during primate evolution the functional gene was lost. Our analysis reveals that GC-D is a pseudogene in a large number of primate species, including apes, Old World and New World monkeys and tarsier. In contrast, the gene appears intact and has evolved under purifying selection in mouse, rat, dog, lemur and bushbaby.These data suggest that signaling through GC-D-expressing cells was probably compromised more than 40 million years ago, prior to the divergence of New World monkeys from Old World monkeys and apes, and thus cannot be involved in chemosensation in most primates.

  17. Duration and specificity of olfactory nonassociative memory.

    Science.gov (United States)

    Freedman, Kaitlin G; Radhakrishna, Sreya; Escanilla, Olga; Linster, Christiane

    2013-05-01

    Olfactory habituation is a simple form of nonassociative memory in which responsiveness to stable but behaviorally nonsignificant stimuli is decreased. Olfactory habituation has recently become a paradigm widely used to probe the neural substrate underlying olfactory perception and memory. This simple behavioral paradigm has been used successfully used to probe many aspects of olfactory processing, and it has recently become clear that the neural processes underlying olfactory habituation can depend on the task parameters used. We here further investigate memory specificity and duration using 2 variations in task parameters: the number of habituation trials and the time delay between habituation and cross-habituation testing. We find that memory specificity increases with the number of habituation trials but decreases with time after the last habituation trial.

  18. Different importance of the volatile and non-volatile fractions of an olfactory signature for individual social recognition in rats versus mice and short-term versus long-term memory.

    Science.gov (United States)

    Noack, Julia; Richter, Karin; Laube, Gregor; Haghgoo, Hojjat Allah; Veh, Rüdiger W; Engelmann, Mario

    2010-11-01

    When tested in the olfactory cued social recognition/discrimination test, rats and mice differ in their retention of a recognition memory for a previously encountered conspecific juvenile: Rats are able to recognize a given juvenile for approximately 45 min only whereas mice show not only short-term, but also long-term recognition memory (≥ 24 h). Here we modified the social recognition/social discrimination procedure to investigate the neurobiological mechanism(s) underlying the species differences. We presented a conspecific juvenile repeatedly to the experimental subjects and monitored the investigation duration as a measure for recognition. Presentation of only the volatile fraction of the juvenile olfactory signature was sufficient for both short- and long-term recognition in mice but not rats. Applying additional volatile, mono-molecular odours to the "to be recognized" juveniles failed to affect short-term memory in both species, but interfered with long-term recognition in mice. Finally immunocytochemical analysis of c-Fos as a marker for cellular activation, revealed that juvenile exposure stimulated areas involved in the processing of olfactory signals in both the main and the accessory olfactory bulb in mice. In rats, we measured an increased c-Fos synthesis almost exclusively in cells of the accessory olfactory bulb. Our data suggest that the species difference in the retention of social recognition memory is based on differences in the processing of the volatile versus non-volatile fraction of the individuals' olfactory signature. The non-volatile fraction is sufficient for retaining a short-term social memory only. Long-term social memory - as observed in mice - requires a processing of both the volatile and non-volatile fractions of the olfactory signature. Copyright © 2010 Elsevier Inc. All rights reserved.

  19. Calcium signals in olfactory neurons.

    Science.gov (United States)

    Tareilus, E; Noé, J; Breer, H

    1995-11-09

    Laser scanning confocal microscopy in combination with the fluorescent calcium indicators Fluo-3 and Fura-Red was employed to estimate the intracellular concentration of free calcium ions in individual olfactory receptor neurons and to monitor temporal and spatial changes in the Ca(2+)-level upon stimulation. The chemosensory cells responded to odorants with a significant increase in the calcium concentration, preferentially in the dendritic knob. Applying various stimulation paradigma, it was found that in a population of isolated cells, subsets of receptor neurons display distinct patterns of responsiveness.

  20. A Closer Look at Acid-Base Olfactory Titrations

    Science.gov (United States)

    Neppel, Kerry; Oliver-Hoyo, Maria T.; Queen, Connie; Reed, Nicole

    2005-01-01

    Olfactory titrations using raw onions and eugenol as acid-base indicators are reported. An in-depth investigation on olfactory titrations is presented to include requirements for potential olfactory indicators and protocols for using garlic, onions, and vanillin as acid-base olfactory indicators are tested.

  1. The role of main olfactory and vomeronasal systems in animal ...

    African Journals Online (AJOL)

    In many terrestrial tetrapod, olfactory sensory communication is mediated by two anatomically and functionally distinct sensory systems; the main olfactory system and vomeronasal system (accessory olfactory system). Recent anatomical studies of the central pathways of the olfactory and vomeronasal systems showed that ...

  2. Behavioural and neurophysiological study of olfactory perception and learning in honeybees

    Directory of Open Access Journals (Sweden)

    Jean-Christophe eSandoz

    2011-12-01

    Full Text Available The honeybee Apis mellifera has been a central insect model in the study of olfactory perception and learning for more than a century, starting with pioneer work by Karl von Frisch. Research on olfaction in honeybees has greatly benefited from the advent of a range of behavioural and neurophysiological paradigms in the Lab. Here I review major findings about how the honeybee brain detects, processes, and learns odours, based on behavioural, neuroanatomical and neurophysiological approaches. I first address the behavioural study of olfactory learning, from experiments on free-flying workers visiting artificial flowers to laboratory-based conditioning protocols on restrained individuals. I explain how the study of olfactory learning has allowed understanding the discrimination and generalization ability of the honeybee olfactory system, its capacity to grant special properties to olfactory mixtures as well as to retain individual component information. Next, based on the impressive amount of anatomical and immunochemical studies of the bee brain, I detail our knowledge of olfactory pathways. I then show how functional recordings of odour-evoked activity in the brain allow following the transformation of the olfactory message from the periphery until higher-order central structures. Data from extra- and intracellular electrophysiological approaches as well as from the most recent optical imaging developments are described. Lastly, I discuss results addressing how odour representation changes as a result of experience. This impressive ensemble of behavioural, neuroanatomical and neurophysiological data available in the bee make it an attractive model for future research aiming to understand olfactory perception and learning in an integrative fashion.

  3. Widespread ectopic expression of olfactory receptor genes

    Directory of Open Access Journals (Sweden)

    Yanai Itai

    2006-05-01

    Full Text Available Abstract Background Olfactory receptors (ORs are the largest gene family in the human genome. Although they are expected to be expressed specifically in olfactory tissues, some ectopic expression has been reported, with special emphasis on sperm and testis. The present study systematically explores the expression patterns of OR genes in a large number of tissues and assesses the potential functional implication of such ectopic expression. Results We analyzed the expression of hundreds of human and mouse OR transcripts, via EST and microarray data, in several dozens of human and mouse tissues. Different tissues had specific, relatively small OR gene subsets which had particularly high expression levels. In testis, average expression was not particularly high, and very few highly expressed genes were found, none corresponding to ORs previously implicated in sperm chemotaxis. Higher expression levels were more common for genes with a non-OR genomic neighbor. Importantly, no correlation in expression levels was detected for human-mouse orthologous pairs. Also, no significant difference in expression levels was seen between intact and pseudogenized ORs, except for the pseudogenes of subfamily 7E which has undergone a human-specific expansion. Conclusion The OR superfamily as a whole, show widespread, locus-dependent and heterogeneous expression, in agreement with a neutral or near neutral evolutionary model for transcription control. These results cannot reject the possibility that small OR subsets might play functional roles in different tissues, however considerable care should be exerted when offering a functional interpretation for ectopic OR expression based only on transcription information.

  4. Olfactory Functioning in First-Episode Psychosis.

    Science.gov (United States)

    Kamath, Vidyulata; Lasutschinkow, Patricia; Ishizuka, Koko; Sawa, Akira

    2018-04-06

    Though olfactory deficits are well-documented in schizophrenia, fewer studies have examined olfactory performance profiles across the psychosis spectrum. The current study examined odor identification, discrimination, and detection threshold performance in first-episode psychosis (FEP) patients diagnosed with schizophrenia, schizoaffective disorder, bipolar disorder with psychotic features, major depression with psychotic features, and other psychotic conditions. FEP patients (n = 97) and healthy adults (n = 98) completed birhinal assessments of odor identification, discrimination, and detection threshold sensitivity for lyral and citralva. Participants also completed measures of anticipatory pleasure, anhedonia, and empathy. Differences in olfactory performances were assessed between FEP patients and controls and within FEP subgroups. Sex-stratified post hoc analyses were employed for a complete analysis of sex differences. Relationships between self-report measures and olfactory scores were also examined. Individuals with psychosis had poorer scores across all olfactory measures when compared to the control group. Within the psychosis cohort, patients with schizophrenia-associated psychosis had poorer odor identification, discrimination, and citralva detection threshold scores relative to controls. In schizophrenia patients, greater olfactory disturbance was associated with increased negative symptomatology, greater self-reported anhedonia, and lower self-reported anticipatory pleasure. Patients with mood-associated psychosis performed comparable to controls though men and women in this cohort showed differential olfactory profiles. These findings indicate that olfactory deficits extend beyond measures of odor identification in FEP with greater deficits observed in schizophrenia-related subgroups of psychosis. Studies examining whether greater olfactory dysfunction confers greater risk for developing schizophrenia relative to other forms of psychosis are

  5. Cigarette Smoke-Induced Cell Death Causes Persistent Olfactory Dysfunction in Aged Mice

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    Rumi Ueha

    2018-06-01

    Full Text Available Introduction: Exposure to cigarette smoke is a cause of olfactory dysfunction. We previously reported that in young mice, cigarette smoke damaged olfactory progenitors and decreased mature olfactory receptor neurons (ORNs, then, mature ORNs gradually recovered after smoking cessation. However, in aged populations, the target cells in ORNs by cigarette smoke, the underlying molecular mechanisms by which cigarette smoke impairs the regenerative ORNs, and the degree of ORN regeneration after smoking cessation remain unclear.Objectives: To explore the effects of cigarette smoke on the ORN cell system using an aged mouse model of smoking, and to investigate the extent to which smoke-induced damage to ORNs recovers following cessation of exposure to cigarette smoke in aged mice.Methods: We intranasally administered a cigarette smoke solution (CSS to 16-month-old male mice over 24 days, then examined ORN existence, cell survival, changes of inflammatory cytokines in the olfactory epithelium (OE, and olfaction using histological analyses, gene analyses and olfactory habituation/dishabituation tests.Results: CSS administration reduced the number of mature ORNs in the OE and induced olfactory dysfunction. These changes coincided with an increase in the number of apoptotic cells and Tumor necrosis factor (TNF expression and a decrease in Il6 expression. Notably, the reduction in mature ORNs did not recover even on day 28 after cessation of treatment with CSS, resulting in persistent olfactory dysfunction.Conclusion: In aged mice, by increasing ORN death, CSS exposure could eventually overwhelm the regenerative capacity of the OE, resulting in continued reduction in the number of mature ORNs and olfactory dysfunction.

  6. Clinical diagnosis and treatment of olfactory meningioma

    International Nuclear Information System (INIS)

    Li Xiangdong; Wang Zhong; Zhang Shiming; Zhu Fengqing; Zhou Dai; Hui Guozhen

    2005-01-01

    Objective: To analyze the clinical diagnosis and treatment of olfactory meningioma. Methods: In this group 17 olfactory meningiomas were operated, and the clinical presentations and the surgery results were obtained. Results: The symptoms of psychiatrical disorder, visual disturbances and eclipse at presentation was higher. In 16 cases the grade of resection was Simpson II, 1 case Simpson III, most of the cases had a good recovery. Conclusion: Attention should be paid to the early symptom at presentation such as psychiatrical disorder to obtain an early diagnosis. Microsurgery is useful in the treatment of olfactory meningioma. (authors)

  7. Adult neurogenesis in the olfactory system shapes odor memory and perception.

    Science.gov (United States)

    Gheusi, Gilles; Lledo, Pierre-Marie

    2014-01-01

    The olfactory system is a dynamic place. In mammals, not only are sensory neurons located in the sensory organ renewed through adult life, but also its first central relay is reconstructed by continuous neuronal recruitment. Despite these numerous morphological and physiological changes, olfaction is a unique sensory modality endowed with a privileged link to memory. This raises a clear conundrum; how does the olfactory system balance its neuronal turnover with its participation in long-term memory? This review concentrates on the functional aspects of adult neurogenesis, addressing how the integration of late-born neurons participates in olfactory perception and memory. After outlining the properties of adult neurogenesis in the olfactory system, and after describing their regulation by internal and environmental factors, we ask how the process of odorant perception can be influenced by constant neuronal turnover. We then explore the possible functional roles that newborn neurons might have for olfactory memory. Throughout this review, and as we concentrate almost exclusively on mammalian models, we stress the idea that adult neurogenesis is yet another form of plasticity used by the brain to copes with a constantly changing olfactory world. © 2014 Elsevier B.V. All rights reserved.

  8. The Accessory Olfactory System Facilitates the Recovery of the Attraction to Familiar Volatile Female Odors in Male Mice.

    Science.gov (United States)

    Muroi, Yoshikage; Nishimura, Masakazu; Ishii, Toshiaki

    2017-10-31

    Odors in female mice induce sexual arousal in male mice. Repeated exposure to female odors attenuates male attraction, which recovers when the odors are removed. The neuronal mechanisms for the recovery of male attraction have not been clarified. In this study, we examined how olfactory systems are involved in the recovery of male attraction to female odors following habituation in mice. Presentation with volatile female odors for 5 min induced habituation in males. To evaluate male attraction to familiar volatile female odors, we measured the duration for investigating volatile female odors from the same female mouse, which was presented twice for 5 min with 1-, 3-, or 5-min interval. Intranasal irrigation with ZnSO4 solution almost completely suppressed investigating behavior, indicating that the main olfactory system is indispensable for inducing the attraction to volatile female odors. In contrast, removal of the vomeronasal organ, bilateral lesions of the accessory olfactory bulb (AOB), or pharmacological blockage of neurotransmission in the AOB did not affect the investigation time at the first odor presentation. However, each one of the treatments decreased the investigation time in the second presentation, compared to that in the first presentation, at longer intervals than control treatment, indicating that the disturbance of neurotransmission in the accessory olfactory system delayed the recovery of the attraction attenuated by the first presentation. These results suggest that the accessory olfactory system facilitates the recovery of the attraction to familiar volatile female odors in male mice. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  9. Olfactory memory capacity of the cricket Gryllus bimaculatus.

    Science.gov (United States)

    Matsumoto, Yukihisa; Mizunami, Makoto

    2006-12-22

    Olfactory learning in insects is a useful model for studying neural mechanisms underlying learning and memory, but memory storage capacity for olfactory learning in insects has not been studied. We investigate whether crickets are capable of simultaneously memorizing seven odour pairs. Fourteen odours were grouped into seven A/B pairs, and crickets in one group were trained to associate A odours with water reward and B odours with saline punishment for all the seven pairs. Crickets in another group were trained with the opposite stimulus arrangement. Crickets in all the groups exhibited significantly greater preference for the odours associated with water reward for all the seven odour pairs. We conclude that crickets are capable of memorizing seven odour pairs at the same time.

  10. Radioinhibition process in Argentinian garlic and onion bulbs

    Science.gov (United States)

    Curzio, O. A.; Croci, C. A.

    Technological aspects of garlic and onion bulbs subjected to the radioinhibition process and extended storage under warehouse conditions were studied. Garlic and onion of the "Colorado" and "Valenciana sintética 14" varieties respectively, were irradiated in dormancy period with an average dose of 50.0 Gy of 60Co gamma rays and kept in storage up to ten months post-harvest. Throughout the control period (180-300 days post-harvest) obvious benefits were attained as to reducing the weight loss and increasing the percentage of marketable bulbs. In general, the irradiated bulbs were superior to the non-irradiated ones with regard to the external aspect, firmness and internal aspect, while the odor of the bulbs was not affected by the process. The radioinhibition process does not seem to affect adversely the levels of dry matter, carbohydrates and ascorbic acid as well as the acidity in onion bulbs. In two marketing trials a very favourable reception was perceived in the consumer public regarding the quality of the products. These studies have promoted the construction of a multipurpose irradiation facility in the Universidad Nacional del Sur for the development of the radiation processing technology.

  11. Olfactory cuing of autobiographical memory.

    Science.gov (United States)

    Rubin, D C; Groth, E; Goldsmith, D J

    1984-01-01

    In Experiment 1, subjects were presented with either the odors or the names of 15 common objects. In Experiment 2, subjects were presented with either the odors, photographs, or names of 16 common objects. All subjects were asked to describe an autobiographical memory evoked by each cue, to date each memory, and to rate each memory on vividness, pleasantness, and the number of times that the memory had been thought of and talked about prior to the experiment. Compared with memories evoked by photographs or names, memories evoked by odors were reported to be thought of and talked about less often prior to the experiment and were more likely to be reported as never having been thought of or talked about prior to the experiment. No other effects were consistently found, though there was a suggestion that odors might evoke more pleasant and emotional memories than other types of cues. The relation of these results to the folklore concerning olfactory cuing is discussed.

  12. Methods to measure olfactory behavior in mice.

    Science.gov (United States)

    Zou, Junhui; Wang, Wenbin; Pan, Yung-Wei; Lu, Song; Xia, Zhengui

    2015-02-02

    Mice rely on the sense of olfaction to detect food sources, recognize social and mating partners, and avoid predators. Many behaviors of mice, including learning and memory, social interaction, fear, and anxiety are closely associated with their function of olfaction, and behavior tasks designed to evaluate those brain functions may use odors as cues. Accurate assessment of olfaction is not only essential for the study of olfactory system but also critical for proper interpretation of various mouse behaviors, especially learning and memory, emotionality and affect, and sociality. Here we describe a series of behavior experiments that offer multidimensional and quantitative assessments for mouse olfactory function, including olfactory habituation, discrimination, odor preference, odor detection sensitivity, and olfactory memory, with respect to both social and nonsocial odors. Copyright © 2015 John Wiley & Sons, Inc.

  13. Functional neuroanatomy of Drosophila olfactory memory formation

    OpenAIRE

    Guven-Ozkan, Tugba; Davis, Ronald L.

    2014-01-01

    New approaches, techniques and tools invented over the last decade and a half have revolutionized the functional dissection of neural circuitry underlying Drosophila learning. The new methodologies have been used aggressively by researchers attempting to answer three critical questions about olfactory memories formed with appetitive and aversive reinforcers: (1) Which neurons within the olfactory nervous system mediate the acquisition of memory? (2) What is the complete neural circuitry exten...

  14. Management of maxillectomy defect with a hybrid hollow bulb obturator

    Science.gov (United States)

    Singh, Kamleshwar; Singh, Saumyendra V; Mishra, Niraj; Agrawal, Kaushal Kishor

    2013-01-01

    A woman having already undergone maxillectomy came to the department complaining of difficulty in eating and speech. During the construction of an obturator, the bulb area should be hollowed to reduce weight so that the teeth and supporting tissues are not stressed unnecessarily. The conventional open design drains fluid from the adjacent mucosa, possibly increasing the weight of the prosthesis, and is difficult to clean. The closed bulb design does not drain secretions and may cause obstruction and susceptibility to infection in the paranasal and pharyngeal regions, though it is easier to maintain. An alternative to the two designs, combining their advantages, is presented in this report. As the open hollow part of the obturator was shallow, it was easy to clean. Making the inferior part of the bulb hollow and closed led to a reduction in the overall weight of the prosthesis while increasing its resonance. PMID:23436886

  15. Controversial bulb disks still marketed as energy savers

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, W.

    1982-05-24

    Despite a 1980 DOE study showing that incandescent bulb disks decrease lamp efficiency by reducing light output as well as energy consumption, at least two manufacturers are still marketing the disks. The companies claim that the Power Disc and Lite-Saver will extend bulb life up to 100 times and reduce wattage 42%, although they both acknowledge that light output is reduced as much as 74% for a 53% efficiency drop. Some users claim the life-extension feature is important when bulb replacement is difficult. The DOE study concludes that the disks are not cost-effective if the user wants equivalent lighting, and questions some of the manufacturers' advertising claims. Satisfied users counter with reports of good performance and no problems with shock or other safety hazards. (DCK)

  16. Depletion of biogenic amines and enhancement of cholinergic activity in the olfactory bulb and central olfactory connections with chronic methedrine intoxication

    Directory of Open Access Journals (Sweden)

    O. Duarte-Escalante

    1970-06-01

    Full Text Available Em seqüência a estudos anteriores os autores visam, neste relato, a apresentar as alterações histoquímicas que ocorrem no sistema olfatório de gatos nos quais se desenvolveu nítida estereotipia de fungação (sniffing após administração prolongada de metedrina. Foram intoxicados 12 gatos mediante injeções diárias, durante 10 dias, de doses progressivas de metedrina. Os tecidos a examinar (bulbos olfatórios e suas conexões centrais foram preparados histoquimicamente para demonstrar a fluorescência das aminas biogênicas e reações colinérgicas. Mediante algumas modificações à metodologia recomendada por outros pesquisadores, os autores puderam demonstrar a presença de monoaminas e de acetilcolina no bulbo olfatório e de grupos de fibras adrenérgicas curtas e multi-ramificadas que parecem ser conectadas com os neurônios fluorescentes do bulbo olfatório, a partir de onde estabelecem conexões, pelo tracto olfatório medial, com os neurônios do septum e, pelo tracto olfatório lateral, com os neurônios do complexo amigdalóide.

  17. [Deficits in medical counseling in olfactory dysfunction].

    Science.gov (United States)

    Haxel, B R; Nisius, A; Fruth, K; Mann, W J; Muttray, A

    2012-05-01

    Olfactory dysfunctions are common with a prevalence of up to 20% in the population. An impaired sense of smell can lead to specific dangers, therefore, counseling and warning of hazardous situations to raise patient awareness is an important medical function. In this study 105 patients presenting to the University of Mainz Medical Centre with dysosmia were evaluated using a questionnaire. For quantification of the olfactory dysfunction a standardized olfactory test (Sniffin' Sticks) was used. Of the patients 46% were hyposmic and 40% were functionally anosmic. The median duration of the olfactory impairment was 10 months and the main causes of dysosmia were upper respiratory tract infections and idiopathic disorders. More than 90% of the patients consulted an otorhinolaryngologist and 60% a general practitioner before presenting to the University of Mainz Medical Center. More than two thirds of the patients conducted a professional activity, 95% of patients reported that they had not received any medical counseling and 6% of the subjects were forced to discontinue their profession because of olfactory dysfunction. In patients with olfactory dysfunctions appropriate diagnostics, including olfactometry should be performed. Furthermore, correct medical counseling concerning necessary additional arrangements (e.g. installation of smoke or gas detectors, precautions while cooking or for hygiene) has to be performed. For patients in a profession an analysis of the hazards at work is crucial.

  18. Insect olfactory memory in time and space.

    Science.gov (United States)

    Liu, Xu; Davis, Ronald L

    2006-12-01

    Recent studies using functional optical imaging have revealed that cellular memory traces form in different areas of the insect brain after olfactory classical conditioning. These traces are revealed as increased calcium signals or synaptic release from defined neurons, and include a short-lived trace that forms immediately after conditioning in antennal lobe projection neurons, an early trace in dopaminergic neurons, and a medium-term trace in dorsal paired medial neurons. New molecular genetic tools have revealed that for normal behavioral memory performance, synaptic transmission from the mushroom body neurons is required only during retrieval, whereas synaptic transmission from dopaminergic neurons is required at the time of acquisition and synaptic transmission from dorsal paired medial neurons is required during the consolidation period. Such experimental results are helping to identify the types of neurons that participate in olfactory learning and when their participation is required. Olfactory learning often occurs alongside crossmodal interactions of sensory information from other modalities. Recent studies have revealed complex interactions between the olfactory and the visual senses that can occur during olfactory learning, including the facilitation of learning about subthreshold olfactory stimuli due to training with concurrent visual stimuli.

  19. Glow curve characteristics of bulb type thermoluminescent dosimeters

    International Nuclear Information System (INIS)

    Deme, S.; Feher, I.; Felszerfalvi, J.

    1993-01-01

    TL dosemeter readers are equipped usually with thermocouples connected to the heater unit. This layout can well be applied to stabilize the position of the glow curve as a function of heating-up time. Bulb type TL dosemeters do not have temperature sensors, no possibility for stabilization, which can cause an additional readout error of dose determination. For this reason, the time dependence of glow curves for bulb-type TL dosemeters was measured, and a new microprocessor controlled readout device was developed. (N.T.) 2 refs.; 2 figs

  20. Olfactory responses to natal stream water in sockeye salmon by BOLD fMRI.

    Directory of Open Access Journals (Sweden)

    Hiroshi Bandoh

    Full Text Available Many studies have shown that juvenile salmon imprint olfactory memory of natal stream odors during downstream migration, and adults recall this stream-specific odor information to discriminate their natal stream during upstream migration for spawning. The odor information processing of the natal stream in the salmon brain, however, has not been clarified. We applied blood oxygenation level-dependent (BOLD functional magnetic resonance imaging to investigate the odor information processing of the natal stream in the olfactory bulb and telencephalon of lacustrine sockeye salmon (Oncorhynchus nerka. The strong responses to the natal stream water were mainly observed in the lateral area of dorsal telencephalon (Dl, which are homologous to the medial pallium (hippocampus in terrestrial vertebrates. Although the concentration of L-serine (1 mM in the control water was 20,000-times higher than that of total amino acid in the natal stream water (47.5 nM, the BOLD signals resulting from the natal stream water were stronger than those by L-serine in the Dl. We concluded that sockeye salmon could process the odor information of the natal stream by integrating information in the Dl area of the telencephalon.

  1. A neuroimaging study of pleasant and unpleasant olfactory perceptions of virgin olive oil

    Directory of Open Access Journals (Sweden)

    J. Vivancos

    2016-12-01

    Full Text Available Functional magnetic resonance imaging (fMRI has been used to collect information from neurons that receive direct input from olfactory bulbs when subjects smell virgin olive oil. The pleasant aroma of three extra virgin olive oils (var. Royal, Arbequina and Picual and three virgin olive oils with sensory defects (rancid, fusty and winey/vinegary were presented to 14 subjects while a fMRI scan acquired data from the brain activity. Data were subjected to a two-sample t test analysis, which allows a better interpretation of results particularly when data are studied across different subjects. Most of the activations, which were located in the frontal lobe, are related to the olfactory task regardless of the hedonic component of perception (e.g. Brodmann areas 10, 11. Comparing the samples with pleasant and unpleasant aromas, differences were found at the anterior cingulate gyrus (Brodmann area 32, at the temporal lobe (Brodmann area 38, and inferior frontal gyrus (Brodmann area 47, while intense aromas activated Brodmann area 6. The actual perceptions described by the subjects and the concentration of the odorant compounds in the samples were considered in the interpretation of the results.

  2. A neuroimaging study of pleasant and unpleasant olfactory perceptions of virgin olive oil

    International Nuclear Information System (INIS)

    Vivancos, J.; Tena, N.; Morales, M.T.; Aparicio, R.; Garcia-Gonzalez, D.L.

    2016-01-01

    Functional magnetic resonance imaging (fMRI) has been used to collect information from neurons that receive direct input from olfactory bulbs when subjects smell virgin olive oil. The pleasant aroma of three extra virgin olive oils (var. Royal, Arbequina and Picual) and three virgin olive oils with sensory defects (rancid, fusty and winey/vinegary) were presented to 14 subjects while a fMRI scan acquired data from the brain activity. Data were subjected to a two-sample t test analysis, which allows a better interpretation of results particularly when data are studied across different subjects. Most of the activations, which were located in the frontal lobe, are related to the olfactory task regardless of the hedonic component of perception (e.g. Brodmann areas 10, 11). Comparing the samples with pleasant and unpleasant aromas, differences were found at the anterior cingulate gyrus (Brodmann area 32), at the temporal lobe (Brodmann area 38), and inferior frontal gyrus (Brodmann area 47), while intense aromas activated Brodmann area 6. The actual perceptions described by the subjects and the concentration of the odorant compounds in the samples were considered in the interpretation of the results. [es

  3. Constitutively expressed Protocadherin-α regulates the coalescence and elimination of homotypic olfactory axons through its cytoplasmic region

    Directory of Open Access Journals (Sweden)

    Sonoko eHasegawa

    2012-10-01

    Full Text Available Olfactory sensory neuron (OSN axons coalesce into specific glomeruli in the olfactory bulb (OB according to their odorant receptor (OR expression. Several guidance molecules enhance the coalescence of homotypic OSN projections, in an OR-specific- and neural-activity-dependent manner. However, the mechanism by which homotypic OSN axons are organized into glomeruli is unsolved. We previously reported that the clustered protocadherin-α (Pcdh-α family of diverse cadherin-related molecules plays roles in the coalescence and elimination of homotypic OSN axons throughout development. Here we showed that the elimination of small ectopic homotypic glomeruli required the constitutive expression of a Pcdh-α isoform and Pcdh-α’s cytoplasmic region, but not OR specificity or neural activity. These results suggest that Pcdh-α proteins provide a cytoplasmic signal to regulate repulsive activity for homotypic OSN axons independently of OR expression and neural activity. The counterbalancing effect of Pcdh-α proteins for the axonal coalescence mechanisms mediated by other olfactory guidance molecules indicate a possible mechanism for the organization of homotypic OSN axons into glomeruli during development.

  4. Structural olfactory nerve changes in patients suffering from idiopathic intracranial hypertension.

    Directory of Open Access Journals (Sweden)

    Christoph Schmidt

    Full Text Available BACKGROUND: Complications of idiopathic intracranial hypertension (IIH are usually caused by elevated intracranial pressure (ICP. In a similar way as in the optic nerve, elevated ICP could also compromise the olfactory nerve system. On the other side, there is growing evidence that an extensive lymphatic network system around the olfactory nerves could be disturbed in cerebrospinal fluid disorders like IIH. The hypothesis that patients with IIH suffer from hyposmia has been suggested in the past. However, this has not been proven in clinical studies yet. This pilot study investigates whether structural changes of the olfactory nerve system can be detected in patients with IIH. METHODOLOGY/PRINCIPAL FINDINGS: Twenty-three patients with IIH and 23 matched controls were included. Olfactory bulb volume (OBV and sulcus olfactorius (OS depth were calculated by magnetic resonance techniques. While mean values of total OBV (128.7±38.4 vs. 130.0±32.6 mm(3, p=0.90 and mean OS depth (8.5±1.2 vs. 8.6±1.1 mm, p=0.91 were similar in both groups, Pearson correlation showed that patients with a shorter medical history IIH revealed a smaller OBV (r=0.53, p<0.01. In untreated symptomatic patients (n=7, the effect was greater (r=0.76, p<0.05. Patients who suffered from IIH for less than one year (n=8, total OBV was significantly smaller than in matched controls (116.6±24.3 vs. 149.3±22.2 mm(3, p=0.01. IIH patients with visual disturbances (n=21 revealed a lower OS depth than patients without (8.3±0.9 vs. 10.8±1.0 mm, p<0.01. CONCLUSIONS/SIGNIFICANCE: The results suggest that morphological changes of the olfactory nerve system could be present in IIH patients at an early stage of disease.

  5. Olfactory processing and odor specificity: a meta-analysis of menstrual cycle variation in olfactory sensitivity

    Directory of Open Access Journals (Sweden)

    Martinec Nováková Lenka

    2014-12-01

    Full Text Available Cycle-correlated variation in olfactory threshold, with women becoming more sensitive to odors mid-cycle, is somewhat supported by the literature but the evidence is not entirely consistent, with several studies finding no, or mixed, effects. It has been argued that cyclic shifts in olfactory threshold might be limited to odors relevant to the mating context.

  6. The protective effect of curcumin in Olfactory Ensheathing Cells exposed to hypoxia.

    Science.gov (United States)

    Bonfanti, Roberta; Musumeci, Teresa; Russo, Cristina; Pellitteri, Rosalia

    2017-02-05

    Curcumin, a phytochemical component derived from the rhizomes of Curcuma longa, has shown a great variety of pharmacological activities, such as anti-inflammatory, anti-tumor, anti-depression and anti-oxidant activity. Therefore, in the last years it has been used as a therapeutic agent since it confers protection in different neurodegenerative diseases, cerebral ischemia and excitotoxicity. Olfactory Ensheathing Cells (OECs) are glial cells of the olfactory system. They are able to secrete several neurotrophic growth factors, promote axonal growth and support the remyelination of damaged axons. OEC transplantation has emerged as a possible experimental therapy to induce repair of spinal cord injury, even if the functional recovery is still limited. Since hypoxia is a secondary effect in spinal cord injury, this in vitro study investigates the protective effect of curcumin in OECs exposed to hypoxia. Primary OECs were obtained from neonatal rat olfactory bulbs and placed both in normal and hypoxic conditions. Furthermore, some cells were grown with basic Fibroblast Growth Factor (bFGF) and/or curcumin at different concentration and times. The results obtained through immunocytochemical procedures and MTT test show that curcumin stimulates cell viability in OECs grown in normal and hypoxic conditions. Furthermore, the synergistic effect o