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Sample records for model olfactory bulb

  1. Functional neurology of a brain system: a 3D olfactory bulb model to process natural odorants.

    Science.gov (United States)

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

    2013-01-01

    The network of interactions between mitral and granule cells in the olfactory bulb is a critical step in the processing of odor information underlying the neural basis of smell perception. We are building the first computational model in 3 dimensions of this network in order to analyze the rules for connectivity and function within it. The initial results indicate that this network can be modeled to simulate experimental results on the activation of the olfactory bulb by natural odorants, providing a much more powerful approach for 3D simulation of brain neurons and microcircuits.

  2. 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

  3. Impaired adult olfactory bulb neurogenesis in the R6/2 mouse model of Huntington's disease

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    Kohl Zacharias

    2010-09-01

    Full Text Available Abstract Background Huntington's disease (HD is an autosomal dominant neurodegenerative disorder linked to expanded CAG-triplet nucleotide repeats within the huntingtin gene. Intracellular huntingtin aggregates are present in neurons of distinct brain areas, among them regions of adult neurogenesis including the hippocampus and the subventricular zone/olfactory bulb system. Previously, reduced hippocampal neurogenesis has been detected in transgenic rodent models of HD. Therefore, we hypothesized that mutant huntingtin also affects newly generated neurons derived from the subventricular zone of adult R6/2 HD mice. Results We observed a redirection of immature neuroblasts towards the striatum, however failed to detect new mature neurons. We further analyzed adult neurogenesis in the granular cell layer and the glomerular layer of the olfactory bulb, the physiological target region of subventricular zone-derived neuroblasts. Using bromodeoxyuridine to label proliferating cells, we observed in both neurogenic regions of the olfactory bulb a reduction in newly generated neurons. Conclusion These findings suggest that the striatal environment, severely affected in R6/2 mice, is capable of attracting neuroblasts, however this region fails to provide sufficient signals for neuronal maturation. Moreover, in transgenic R6/2 animals, the hostile huntingtin-associated microenvironment in the olfactory bulb interferes with the survival and integration of new mature neurons. Taken together, endogenous cell repair strategies in HD may require additional factors for the differentiation and survival of newly generated neurons both in neurogenic and non-neurogenic regions.

  4. Computational modeling suggests distinct, location-specific function of norepinephrine in olfactory bulb and piriform cortex

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    Licurgo ede Almeida

    2015-06-01

    Full Text Available Noradrenergic modulation from the locus coerulus is often associated with the regulation of sensory signal-to-noise ratio. In the olfactory system, noradrenergic modulation affects both bulbar and cortical processing, and has been show to modulate the detection of low concentration stimuli. We here implemented a computational model of the olfactory bulb and piriform cortex, based on known experimental results, to explore how noradrenergic modulation in the olfactory bulb and piriform cortex interact to regulate odor processing. We show that as predicted by behavioral experiments in our lab, norepinephrine can play a critical role in modulating the detection and associative learning of very low odor concentrations. Our simulations show that bulbar norepinephrine serves to pre-process odor representations to facilitate cortical learning, but not recall. We observe the typical non-uniform dose – response functions described for norepinephrine modulation and show that these are imposed mainly by bulbar, but not cortical processing.

  5. Computational modeling suggests distinct, location-specific function of norepinephrine in olfactory bulb and piriform cortex.

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    de Almeida, Licurgo; Reiner, Seungdo J; Ennis, Matthew; Linster, Christiane

    2015-01-01

    Noradrenergic modulation from the locus coerulus is often associated with the regulation of sensory signal-to-noise ratio. In the olfactory system, noradrenergic modulation affects both bulbar and cortical processing, and has been shown to modulate the detection of low concentration stimuli. We here implemented a computational model of the olfactory bulb and piriform cortex, based on known experimental results, to explore how noradrenergic modulation in the olfactory bulb and piriform cortex interact to regulate odor processing. We show that as predicted by behavioral experiments in our lab, norepinephrine can play a critical role in modulating the detection and associative learning of very low odor concentrations. Our simulations show that bulbar norepinephrine serves to pre-process odor representations to facilitate cortical learning, but not recall. We observe the typical non-uniform dose-response functions described for norepinephrine modulation and show that these are imposed mainly by bulbar, but not cortical processing.

  6. Neuronal organization of olfactory bulb circuits

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    Shin eNagayama

    2014-09-01

    Full Text Available Olfactory sensory neurons extend their axons solely to the olfactory bulb, which is dedicated to odor information processing. The olfactory bulb is divided into multiple layers, with different types of neurons found in each of the layers. Therefore, neurons in the olfactory bulb have conventionally been categorized based on the layers in which their cell bodies are found; namely, juxtaglomerular cells in the glomerular layer, tufted cells in the external plexiform layer, mitral cells in the mitral cell layer, and granule cells in the granule cell layer. More recently, numerous studies have revealed the heterogeneous nature of each of these cell types, allowing them to be further divided into subclasses based on differences in morphological, molecular, and electrophysiological properties. In addition, technical developments and advances have resulted in an increasing number of studies regarding cell types other than the conventionally categorized ones described above, including short-axon cells and adult-generated interneurons. Thus, the expanding diversity of cells in the olfactory bulb is now being acknowledged. However, our current understanding of olfactory bulb neuronal circuits is mostly based on the conventional and simplest classification of cell types. Few studies have taken neuronal diversity into account for understanding the function of the neuronal circuits in this region of the brain. This oversight may contribute to the roadblocks in developing more precise and accurate models of olfactory neuronal networks. The purpose of this review is therefore to discuss the expanse of existing work on neuronal diversity in the olfactory bulb up to this point, so as to provide an overall picture of the olfactory bulb circuit.

  7. A model of cholinergic modulation in olfactory bulb and piriform cortex.

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    de Almeida, Licurgo; Idiart, Marco; Linster, Christiane

    2013-03-01

    In this work we investigate in a computational model how cholinergic inputs to the olfactory bulb (OB) and piriform cortex (PC) modulate odor representations. We use experimental data derived from different physiological studies of ACh modulation of the bulbar and cortical circuitry and the interaction between these two areas. The results presented here indicate that cholinergic modulation in the OB significantly increases contrast and synchronization in mitral cell output. Each of these effects is derived from distinct neuronal interactions, with different groups of interneurons playing different roles. Both bulbar modulation effects contribute to more stable learned representations in PC, with pyramidal networks trained with cholinergic-modulated inputs from the bulb exhibiting more robust learning than those trained with unmodulated bulbar inputs. This increased robustness is evidenced as better recovery of memories from corrupted patterns and lower-concentration inputs as well as increased memory capacity.

  8. 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.

  9. Centrifugal innervation of the mammalian olfactory bulb.

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    Matsutani, Shinji; Yamamoto, Noboru

    2008-12-01

    Although it has been known for decades that the mammalian olfactory bulb receives a substantial number of centrifugal inputs from other regions of the brain, relatively few data have been available on the function of the centrifugal olfactory system. Knowing the role of the centrifugal projection and how it works is of critical importance to fully understanding olfaction. The centrifugal fibers can be classified into two groups, a group that release neuromodulators, such as noradrenaline, serotonin, or acetylcholine, and a group originating in the olfactory cortex. Accumulating evidence suggests that centrifugal neuromodulatory inputs are associated with acquisition of odor memory. Because the distribution of the terminals on these fibers is diffuse and widespread, the neuromodulatory inputs must affect diverse subsets of bulbar neurons at the same time. In contrast, knowledge of the role of centrifugal fibers from the olfactory cortical areas is limited. Judging from recent morphological evidence, these fibers may modify the activity of neurons located in sparse and discrete loci in the olfactory bulb. Given the modular organization of the olfactory bulb, centrifugal fibers from the olfactory cortex may help coordinate the activities of restricted subsets of neurons belonging to distinct functional modules in an odor-specific manner. Because the olfactory cortex receives inputs from limbic and neocortical areas in addition to inputs from the bulb, the centrifugal inputs from the cortex can modulate odor processing in the bulb in response to non-olfactory as well as olfactory cues.

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

    OpenAIRE

    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

    2009-01-01

    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 Pe...

  11. Olfactory consciousness and gamma oscillation couplings across the olfactory bulb, olfactory cortex, and orbitofrontal cortex.

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    Mori, Kensaku; Manabe, Hiroyuki; Narikiyo, Kimiya; Onisawa, Naomi

    2013-01-01

    The orbitofrontal cortex receives multi-modality sensory inputs, including olfactory input, and is thought to be involved in conscious perception of the olfactory image of objects. Generation of olfactory consciousness may require neuronal circuit mechanisms for the "binding" of distributed neuronal activities, with each constituent neuron representing a specific component of an olfactory percept. The shortest neuronal pathway for odor signals to reach the orbitofrontal cortex is olfactory sensory neuron-olfactory bulb-olfactory cortex-orbitofrontal cortex, but other pathways exist, including transthalamic pathways. Here, we review studies on the structural organization and functional properties of the shortest pathway, and propose a model of neuronal circuit mechanisms underlying the temporal bindings of distributed neuronal activities in the olfactory cortex. We describe a hypothesis that suggests functional roles of gamma oscillations in the bindings. This hypothesis proposes that two types of projection neurons in the olfactory bulb, tufted cells and mitral cells, play distinct functional roles in bindings at neuronal circuits in the olfactory cortex: tufted cells provide specificity-projecting circuits which send odor information with early-onset fast gamma synchronization, while mitral cells give rise to dispersedly-projecting feed-forward binding circuits which transmit the response synchronization timing with later-onset slow gamma synchronization. This hypothesis also suggests a sequence of bindings in the olfactory cortex: a small-scale binding by the early-phase fast gamma synchrony of tufted cell inputs followed by a larger-scale binding due to the later-onset slow gamma synchrony of mitral cell inputs. We discuss that behavioral state, including wakefulness and sleep, regulates gamma oscillation couplings across the olfactory bulb, olfactory cortex, and orbitofrontal cortex.

  12. Olfactory consciousness and gamma oscillation couplings across the olfactory bulb, olfactory cortex and orbitofrontal cortex

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    Kensaku eMori

    2013-10-01

    Full Text Available The orbitofrontal cortex receives multi-modality sensory inputs, including olfactory input, and is thought to be involved in conscious perception of the olfactory image of objects. Generation of olfactory consciousness requires neuronal circuit mechanisms for the ‘binding’ of distributed neuronal activities, with each constituent neuron representing a specific component of an olfactory percept. The shortest neuronal pathway for odor signals to reach the orbitofrontal cortex is olfactory sensory neuron – olfactory bulbolfactory cortex – orbitofrontal cortex, but other pathways exist, including transthalamic pathways. Here, we review studies on the structural organization and functional properties of the shortest pathway, and propose a model of neuronal circuit mechanisms underlying the temporal bindings of distributed neuronal activities in the olfactory cortex. We describe a hypothesis that suggests functional roles of gamma oscillations in the bindings. This hypothesis proposes that two types of projection neurons in the olfactory bulb, tufted cells and mitral cells, play distinct functional roles in bindings at neuronal circuits in the olfactory cortex: tufted cells provide specificity-projecting circuits which send odor information with early-onset fast gamma synchronization, while mitral cells give rise to dispersedly-projecting feed-forward binding circuits which transmit the response synchronization timing with later-onset slow gamma synchronization. This hypothesis also suggests a sequence of bindings in the olfactory cortex: a small-scale binding by the early-phase fast gamma synchrony of tufted cell inputs followed by a larger-scale binding due to the later-onset slow gamma synchrony of mitral cell inputs. We discuss that behavioral state, including wakefulness and sleep, regulates gamma oscillation couplings across the olfactory bulb, olfactory cortex, and orbitofrontal cortex.

  13. Local neurons play key roles in the mammalian olfactory bulb.

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    Saghatelyan, Armen; Carleton, Alan; Lagier, Samuel; de Chevigny, Antoine; Lledo, Pierre-Marie

    2003-01-01

    Over the past few decades, research exploring how the brain perceives, discriminates, and recognizes odorant molecules has received a growing interest. Today, olfaction is no longer considered a matter of poetry. Chemical senses entered the biological era when an increasing number of scientists started to elucidate the early stages of the olfactory pathway. A combination of genetic, biochemical, cellular, electrophysiological and behavioral methods has provided a picture of how odor information is processed in the olfactory system as it moves from the periphery to higher areas of the brain. Our group is exploring the physiology of the main olfactory bulb, the first processing relay in the mammalian brain. From different electrophysiological approaches, we are attempting to understand the cellular rules that contribute to the synaptic transmission and plasticity at this central relay. How olfactory sensory inputs, originating from the olfactory epithelium located in the nasal cavity, are encoded in the main olfactory bulb remains a crucial question for understanding odor processing. More importantly, the persistence of a high level of neurogenesis continuously supplying the adult olfactory bulb with newborn local neurons provides an attractive model to investigate how basic olfactory functions are maintained when a large proportion of local neurons are continuously renewed. For this purpose, we summarize the current ideas concerning the molecular mechanisms and organizational strategies used by the olfactory system to encode and process information in the main olfactory bulb. We discuss the degree of sensitivity of the bulbar neuronal network activity to the persistence of this high level of neurogenesis that is modulated by sensory experience. Finally, it is worth mentioning that analyzing the molecular mechanisms and organizational strategies used by the olfactory system to transduce, encode, and process odorant information in the olfactory bulb should aid in

  14. Functional differentiation of cholinergic and noradrenergic modulation in a biophysical model of olfactory bulb granule cells.

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    Li, Guoshi; Linster, Christiane; Cleland, Thomas A

    2015-12-01

    Olfactory bulb granule cells are modulated by both acetylcholine (ACh) and norepinephrine (NE), but the effects of these neuromodulators have not been clearly distinguished. We used detailed biophysical simulations of granule cells, both alone and embedded in a microcircuit with mitral cells, to measure and distinguish the effects of ACh and NE on cellular and microcircuit function. Cholinergic and noradrenergic modulatory effects on granule cells were based on data obtained from slice experiments; specifically, ACh reduced the conductance densities of the potassium M current and the calcium-dependent potassium current, whereas NE nonmonotonically regulated the conductance density of an ohmic potassium current. We report that the effects of ACh and NE on granule cell physiology are distinct and functionally complementary to one another. ACh strongly regulates granule cell firing rates and afterpotentials, whereas NE bidirectionally regulates subthreshold membrane potentials. When combined, NE can regulate the ACh-induced expression of afterdepolarizing potentials and persistent firing. In a microcircuit simulation developed to investigate the effects of granule cell neuromodulation on mitral cell firing properties, ACh increased spike synchronization among mitral cells, whereas NE modulated the signal-to-noise ratio. Coapplication of ACh and NE both functionally improved the signal-to-noise ratio and enhanced spike synchronization among mitral cells. In summary, our computational results support distinct and complementary roles for ACh and NE in modulating olfactory bulb circuitry and suggest that NE may play a role in the regulation of cholinergic function.

  15. Functional differentiation of cholinergic and noradrenergic modulation in a biophysical model of olfactory bulb granule cells

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    Linster, Christiane

    2015-01-01

    Olfactory bulb granule cells are modulated by both acetylcholine (ACh) and norepinephrine (NE), but the effects of these neuromodulators have not been clearly distinguished. We used detailed biophysical simulations of granule cells, both alone and embedded in a microcircuit with mitral cells, to measure and distinguish the effects of ACh and NE on cellular and microcircuit function. Cholinergic and noradrenergic modulatory effects on granule cells were based on data obtained from slice experiments; specifically, ACh reduced the conductance densities of the potassium M current and the calcium-dependent potassium current, whereas NE nonmonotonically regulated the conductance density of an ohmic potassium current. We report that the effects of ACh and NE on granule cell physiology are distinct and functionally complementary to one another. ACh strongly regulates granule cell firing rates and afterpotentials, whereas NE bidirectionally regulates subthreshold membrane potentials. When combined, NE can regulate the ACh-induced expression of afterdepolarizing potentials and persistent firing. In a microcircuit simulation developed to investigate the effects of granule cell neuromodulation on mitral cell firing properties, ACh increased spike synchronization among mitral cells, whereas NE modulated the signal-to-noise ratio. Coapplication of ACh and NE both functionally improved the signal-to-noise ratio and enhanced spike synchronization among mitral cells. In summary, our computational results support distinct and complementary roles for ACh and NE in modulating olfactory bulb circuitry and suggest that NE may play a role in the regulation of cholinergic function. PMID:26334007

  16. 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

  17. Olfactory bulb encoding during learning under anesthesia

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    Nicol, Alister U.; Sanchez-Andrade, Gabriela; Collado, Paloma; Segonds-Pichon, Anne; Kendrick, Keith M.

    2014-01-01

    Neural plasticity changes within the olfactory bulb are important for olfactory learning, although how neural encoding changes support new associations with specific odors and whether they can be investigated under anesthesia, 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 odor smelled on the breath of a demonstrator animal occurs under isofluorane anesthesia. Furthermore, subsequent exposure to this cued odor under anesthesia promotes the same pattern of increased release of glutamate and gamma-aminobutyric acid (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 anesthesia before, during and after a novel scented food odor was paired with carbon disulfide. Results showed significant increases in overall firing frequency to the cued-odor during and after learning and decreases in response to an uncued odor. 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 odors prior to learning were either excited or inhibited afterwards. With the uncued odor 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 anesthesia promotes extensive, but spatially distinct, changes in mitral cell networks to both cued and uncued odors as well as in evoked glutamate and GABA

  18. 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.

  19. Neurogenesis in the adult olfactory bulb

    Institute of Scientific and Technical Information of China (English)

    Angela Pignatelli; Cristina Gambardella; Ottorino Belluzzi

    2011-01-01

    Neurogenesis is the process by which cells divide, migrate, and subsequently differentiate into a neuronal phenotype. Significant rates of neurogenesis persist into adulthood in two brain regions, the subgranular zone of the dentate gyrus and the subventricular zone of the lateral ventricles. Cells of the subventricular zone divide and migrate via the rostral migratory stream to the olfactory bulb where they differentiate into granule and periglomerular cells. With the discovery of large-scale neurogenesis in the adult brain, there have been significant efforts to identify the mechanisms that control this process as well as the role of these cells in neuronal functioning. Although many questions remain unanswered, new insights appear daily about adult neurogenesis, regulatory mechanisms, and the fates of the progeny. In this review we highlight the main studies investigating factors that regulate neurogenesis in the subventricular zone, neuronal migration to the olfactory bulb, neuronal integration into the existing bulbar network and shortly discuss the functional meaning of this process.

  20. 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.

  1. Human olfactory bulb neural stem cells expressing hNGF restore cognitive deficit in Alzheimer's disease rat model.

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

    2015-01-01

    In this study, we aim to demonstrate the fate of allogenic adult human olfactory bulb neural stem/progenitor cells (OBNSC/NPCs) transplanted into the rat hippocampus treated with ibotenic acid (IBO), a neurotoxicant specific to hippocampal cholinergic neurons that are lost in Alzheimer's disease. We assessed their possible ability to survive, integrate, proliferate, and differentiate into different neuronal and glial elements: we also evaluate their possible therapeutic potential, and the mechanism(s) relevant to neuroprotection following their engraftment into the CNS milieu. OBNSC/NPCs were isolated from adult human olfactory bulb patients, genetically engineered to express GFP and human nerve growth factor (hNGF) by lentivirus-mediated infection, and stereotaxically transplanted into the hippocampus of IBO-treated animals and controls. Stereological analysis of engrafted OBNSCs eight weeks post transplantation revealed a 1.89 fold increase with respect to the initial cell population, indicating a marked ability for survival and proliferation. In addition, 54.71 ± 11.38%, 30.18 ± 6.00%, and 15.09 ± 5.38% of engrafted OBNSCs were identified by morphological criteria suggestive of mature neurons, oligodendrocytes and astrocytes respectively. Taken together, this work demonstrated that human OBNSCs expressing NGF ameliorate the cognitive deficiencies associated with IBO-induced lesions in AD model rats, and the improvement can probably be attributed primarily to neuronal and glial cell replacement as well as the trophic influence exerted by the secreted NGF. © 2014 Wiley Periodicals, Inc.

  2. Enhanced assymetrical noradrenergic transmission in the olfactory bulb of deoxycorticosterone acetate-salt hypertensive rats.

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    Abramoff, Tamara; Guil, María J; Morales, Vanina P; Hope, Sandra I; Soria, Celeste; Bianciotti, Liliana G; Vatta, Marcelo S

    2013-10-01

    The ablation of olfactory bulb induces critical changes in dopamine, and monoamine oxidase activity in the brain stem. Growing evidence supports the participation of this telencephalic region in the regulation blood pressure and cardiovascular activity but little is known about its contribution to hypertension. We have previously reported that in the olfactory bulb of normotensive rats endothelins enhance noradrenergic activity by increasing tyrosine hydroxylase activity and norepinephrine release. In the present study we sought to establish the status of noradrenergic activity in the olfactory bulb of deoxycorticosterone acetate (DOCA)-salt hypertensive rats. Different steps in norepinephrine transmission including tyrosine hydroxylase activity, neuronal norepinephrine release and uptake were assessed in the left and right olfactory bulb of DOCA-salt hypertensive rats. Increased tyrosine hydroxylase activity, and decreased neuronal norepinephrine uptake were observed in the olfactory bulb of DOCA-salt hypertensive rats. Furthermore the expression of tyrosine hydroxylase and its phosphorylated forms were also augmented. Intriguingly, asymmetrical responses between the right and left olfactory bulb of normotensive and hypertensive rats were observed. Neuronal norepinephrine release was increased in the right but not in the left olfactory bulb of DOCA-salt hypertensive rats, whereas non asymmetrical differences were observed in normotensive animals. Present findings indicate that the olfactory bulb of hypertensive rats show an asymmetrical increase in norepinephrine activity. The observed changes in noradrenergic transmission may likely contribute to the onset and/or progression of hypertension in this animal model.

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

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    Zhang, Zhong-Hao; Chen, Chen; Wu, Qiu-Yan; Zheng, Rui; Chen, Yao; Liu, Qiong; Ni, Jia-Zuan; Song, Guo-Li

    2016-01-01

    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. PMID:27689994

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

    Directory of Open Access Journals (Sweden)

    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.

  5. Signal processing inspired from the olfactory bulb for electronic noses

    Science.gov (United States)

    Jing, Ya-Qi; Meng, Qing-Hao; Qi, Pei-Feng; Zeng, Ming; Liu, Ying-Jie

    2017-01-01

    A bio-inspired signal processing method is proposed for electronic noses (e-noses). The proposed method contains an olfactory bulb model and a feature generation step. The structure of the olfactory bulb model is similar to the anatomical structure of mammals’ olfactory bulb. It consists of olfactory receptor neurons, mitral cells, granule cells, periglomerular cells, and short axon cells. This model uses gas sensors’ original response curves and transforms them to neuron spiking series no matter what kind the response curve is. This largely simplifies the follow-up feature generation step. Recurrence quantification analysis is employed to perform feature generation and the five most important features are selected. Finally, in order to verify the performance of the proposed method, seven kinds of Chinese liquors are tested and three classification methods are used to classify them. The experimental results demonstrate that the proposed method has a higher classification rate (99.05%) and also a steadier performance with the change of sensor number and types than the classic one.

  6. Function of attention in learning process in the olfactory bulb

    Institute of Scientific and Technical Information of China (English)

    马宝生; 王顺鹏; 李岩; 冯春华; 郭爱克

    2003-01-01

    It has been suggested that in the olfactory bulb, odor information is processed through parallel channels and learning depends on the cognitive environment. The synapse's spike effective time is defined as the effective time for a spike from pre-synapse to post-synapse, which varies with the type of synapse. A learning model of the olfactory bulb was constructed for synapses with varying spike effective times. The simulation results showed that such a model can realize the multi-channel processing of information in the bulb. Furthermore, the effect of the cognitive environment on the learning process was also studied. Different feedback frequencies were used to express different attention states. Considering the information's multi-channel processing requirement for learning, a learning rule considering both spike timing and average spike frequency is proposed. Simulation results showed that habituation and anti-habituation of an odor in the olfactory bulb might be the result of learning guided by a common local learning rule but at different attention states.

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

    Energy Technology Data Exchange (ETDEWEB)

    Azoulay, Robin; Grabar, Sophie; Kalifa, Gabriel; Adamsbaum, Catherine [Paris V, Faculte de Medecine, Department of Radiology, Hopital Saint Vincent de Paul, Paris Cedex 14 (France); Fallet-Bianco, Catherine [Hopital Sainte-Anne, Paris (France); Garel, Catherine [Hopital Robert Debre, Paris (France)

    2006-02-01

    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.)

  8. Localization of neurotrophin receptors in olfactory epithelium and bulb.

    Science.gov (United States)

    Deckner, M L; Frisén, J; Verge, V M; Hökfelt, T; Risling, M

    1993-12-13

    We used in situ hybridization to localize trk, trkB and trkC mRNA, in rat and cat olfactory bulb. Expression of mRNA encoding truncated trkB receptors was seen in all layers, while only very modest full-length trkB expression could be detected. trkC hybridization was seen in all layers, most dense in the mitral cell layer. The localization of full-length tyrosine kinase trkB receptor in olfactory bulb and epithelium was examined with immunohistochemistry. trkB-like immunoreactivity was seen in the fila olfactoria, epithelium and in vitro, in olfactory sensory neurones. Since BDNF is expressed by olfactory sensory neurone target cells in the olfactory bulb, these data suggest that BDNF may act as a target derived neurotrophic factor in the primary olfactory system.

  9. Neural sensitivity to odorants in deprived and normal olfactory bulbs.

    Directory of Open Access Journals (Sweden)

    Francisco B Rodríguez

    Full Text Available Early olfactory deprivation in rodents is accompanied by an homeostatic regulation of the synaptic connectivity in the olfactory bulb (OB. However, its consequences in the neural sensitivity and discrimination have not been elucidated. We compared the odorant sensitivity and discrimination in early sensory deprived and normal OBs in anesthetized rats. We show that the deprived OB exhibits an increased sensitivity to different odorants when compared to the normal OB. Our results indicate that early olfactory stimulation enhances discriminability of the olfactory stimuli. We found that deprived olfactory bulbs adjusts the overall excitatory and inhibitory mitral cells (MCs responses to odorants but the receptive fields become wider than in the normal olfactory bulbs. Taken together, these results suggest that an early natural sensory stimulation sharpens the receptor fields resulting in a larger discrimination capability. These results are consistent with previous evidence that a varied experience with odorants modulates the OB's synaptic connections and increases MCs selectivity.

  10. Synaptic clusters function as odor operators in the olfactory bulb

    OpenAIRE

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

    2015-01-01

    How the olfactory bulb organizes and processes odor inputs through fundamental operations of its microcircuits is still controversial. To reveal these operations we hypothesize that one of the key mechanisms underlying odor coding is the interaction among spatially restricted and well-defined clusters of potentiated mitral–granule cell synapses. These experimentally observed clusters selectively gate the propagation of neuronal activity within the olfactory bulb and extensively contribute to ...

  11. Exploring parameter space in detailed single neuron models: simulations of the mitral and granule cells of the olfactory bulb.

    Science.gov (United States)

    Bhalla, U S; Bower, J M

    1993-06-01

    1. Detailed compartmental computer simulations of single mitral and granule cells of the vertebrate olfactory bulb were constructed using previously published geometric data. Electrophysiological properties were determined by comparing model output to previously published experimental data, mainly current-clamp recordings. 2. The passive electrical properties of each model were explored by comparing model output with intracellular potential data from hyperpolarizing current injection experiments. The results suggest that membrane resistivity in both cells is nonuniform, with somatas having a substantially lower resistivity than the dendrites. 3. The active properties of these cells were explored by incorporating active ion channels into modeled compartments. On the basis of evidence from the literature, the mitral cell model included six channel types: fast sodium, fast delayed rectifier (Kfast), slow delayed rectifier (K), transient outward potassium current (KA), voltage- and calcium-dependent potassium current (KCa), and L-type calcium current. The granule cell model included four channel types: rat brain sodium, K, KA, and the non-inactivating muscarinic potassium current (KM). Modeled channels were based on the Hodgkin-Huxley formalism. 4. Representative kinetics for each of the channel classes above were obtained from the literature. The experimentally unknown spatial distributions of each included channel were obtained by systematic parameter searches. These were conducted in two ways: large-scale simulation series, in which each parameter was varied in turn, and an adaptation of a multidimensional conjugate gradient method. In each case, the simulated results were compared wtih experimental data using a curve-matching function evaluating mean squared differences of several aspects of the simulated and experimental voltage waveforms. 5. Systematic parameter variations revealed a single distinct region of parameter space in which the mitral cell model best

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

    Science.gov (United States)

    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…

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

    Science.gov (United States)

    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…

  14. Broadcasting of cortical activity to the olfactory bulb.

    Science.gov (United States)

    Boyd, Alison M; Kato, Hiroyuki K; Komiyama, Takaki; Isaacson, Jeffry S

    2015-02-24

    Odor representations are initially formed in the olfactory bulb, which contains a topographic glomerular map of odor molecular features. The bulb transmits sensory information directly to piriform cortex, where it is encoded by distributed ensembles of pyramidal cells without spatial order. Intriguingly, piriform cortex pyramidal cells project back to the bulb, but the information contained in this feedback projection is unknown. Here, we use imaging in awake mice to directly monitor activity in the presynaptic boutons of cortical feedback fibers. We show that the cortex provides the bulb with a rich array of information for any individual odor and that cortical feedback is dependent on brain state. In contrast to the stereotyped, spatial arrangement of olfactory bulb glomeruli, cortical inputs tuned to different odors commingle and indiscriminately target individual glomerular channels. Thus, the cortex modulates early odor representations by broadcasting sensory information diffusely onto spatially ordered bulbar circuits.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    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.

  17. Analytical processing of binary mixture information by olfactory bulb glomeruli.

    Directory of Open Access Journals (Sweden)

    Max L Fletcher

    Full Text Available Odors are rarely composed of a single compound, but rather contain a large and complex variety of chemical components. Often, these mixtures are perceived as having unique qualities that can be quite different than the combination of their components. In many cases, a majority of the components of a mixture cannot be individually identified. This synthetic processing of odor information suggests that individual component representations of the mixture must interact somewhere along the olfactory pathway. The anatomical nature of sensory neuron input into segregated glomeruli with the bulb suggests that initial input of odor information into the bulb is analytic. However, a large network of interneurons within the olfactory bulb could allow for mixture interactions via mechanisms such as lateral inhibition. Currently in mammals, it is unclear if postsynaptic mitral/tufted cell glomerular mixture responses reflect the analytical mixture input, or provide the initial basis for synthetic processing with the olfactory system. To address this, olfactory bulb glomerular binary mixture representations were compared to representations of each component using transgenic mice expressing the calcium indicator G-CaMP2 in olfactory bulb mitral/tufted cells. Overall, dorsal surface mixture representations showed little mixture interaction and often appeared as a simple combination of the component representations. Based on this, it is concluded that dorsal surface glomerular mixture representations remain largely analytical with nearly all component information preserved.

  18. The olfactory bulb and the number of its glomeruli in the common marmoset (Callithrix jacchus).

    Science.gov (United States)

    Moriya-Ito, Keiko; Tanaka, Ikuko; Umitsu, Yoshitomo; Ichikawa, Masumi; Tokuno, Hironobu

    2015-04-01

    The olfactory system has been well studied in mammals such as mice and rats. However, few studies have focused on characterizing this system in diurnal primates that rely on their sense of smell to a lesser extent due to their ecological environment. In the present study, we determined the histological organization of the olfactory bulb in the common marmoset (Callithrix jacchus). We then constructed 3-dimensional models of the glomeruli of the olfactory bulb, and estimated the number of glomeruli. Olfactory glomeruli are the functional units of olfactory processing, and have been investigated in detail using mice. There are approximately 1800 glomeruli in a mouse hemibulb, and olfactory sensory neurons expressing one selected olfactory receptor converge onto one or two glomeruli. Because mice have about 1000 olfactory receptor genes, it is proposed that the number of glomeruli in mammals is nearly double that of olfactory receptor genes. The common marmoset carries only about 400 intact olfactory receptor genes. The present study revealed that the number of glomeruli in a marmoset hemibulb was approximately 1500-1800. This result suggests that the number of glomeruli is not positively correlated with the number of intact olfactory receptor genes in mammals.

  19. Parvalbumin-expressing interneurons linearly control olfactory bulb output.

    Science.gov (United States)

    Kato, Hiroyuki K; Gillet, Shea N; Peters, Andrew J; Isaacson, Jeffry S; Komiyama, Takaki

    2013-12-04

    In the olfactory bulb, odor representations by principal mitral cells are modulated by local inhibitory circuits. While dendrodendritic synapses between mitral and granule cells are typically thought to be a major source of this modulation, the contributions of other inhibitory neurons remain unclear. Here we demonstrate the functional properties of olfactory bulb parvalbumin-expressing interneurons (PV cells) and identify their important role in odor coding. Using paired recordings, we find that PV cells form reciprocal connections with the majority of nearby mitral cells, in contrast to the sparse connectivity between mitral and granule cells. In vivo calcium imaging in awake mice reveals that PV cells are broadly tuned to odors. Furthermore, selective PV cell inactivation enhances mitral cell responses in a linear fashion while maintaining mitral cell odor preferences. Thus, dense connections between mitral and PV cells underlie an inhibitory circuit poised to modulate the gain of olfactory bulb output.

  20. Neurogenesis, neurodegeneration, interneuron vulnerability and amyloid-β in the olfactory bulb of APP/PS1 mouse model of Alzheimer’s disease

    Directory of Open Access Journals (Sweden)

    Carlos eDe La Rosa Prieto

    2016-05-01

    Full Text Available Alzheimer´s disease is the most prevalent neurodegenerative disease, mostly idiopathic and with palliative treatment. Neuropathologically, it is characterized by intracellular neurofibrillary tangles of tau protein and extracellular plaques of amyloid β peptides. The relationship between Alzheimer’s disease and neurogenesis is unknown, but two facts are particularly relevant. First, early aggregation sites of both proteinopathies include the hippocampal formation and the olfactory bulb, which have been correlated to memory and olfactory deficits, respectively. These areas are well-recognized integration zones of newly-born neurons in the adult brain. Second, molecules, such as amyloid precursor protein and presenilin-1 are common to both Alzheimer’s disease etiology and neurogenic development. Adult neurogenesis in Alzheimer’s disease models has been studied in the hippocampus, but only occasionally addressed in the olfactory bulb and results are contradictory. To gain insight on the relationship between adult neurogenesis and Alzheimer’s disease, this work analyzes neurogenesis, neurodegeneration, interneuron vulnerability and amyloid-β involvement in the olfactory bulb of an Alzheimer’s disease model. Control and double-transgenic mice carrying the amyloid precursor protein and the presenilin-1 genes, which give rise amyloid β plaques have been used. BrdU-treated animals have been studied at 16, 30, 43 and 56 weeks of age. New-born cell survival (BrdU, neuronal loss (using neuronal markers NeuN and PGP9.5, differential interneuron (calbindin-, parvalbumin-, calretinin- and somatostatin-expressing populations vulnerability and involvement by amyloid β have been analyzed. Neurogenesis increases with aging in the granule cell layer of control animals from 16 to 43 weeks. No neuronal loss has been observed after quantifying NeuN or PGP9.5. Regarding interneuron population vulnerability: calbindin-expressing neurons remains unchanged

  1. Construction of odor representations by olfactory bulb microcircuits.

    Science.gov (United States)

    Cleland, Thomas A

    2014-01-01

    Like other sensory systems, the olfactory system transduces specific features of the external environment and must construct an organized sensory representation from these highly fragmented inputs. As with these other systems, this representation is not accurate per se, but is constructed for utility, and emphasizes certain, presumably useful, features over others. I here describe the cellular and circuit mechanisms of the peripheral olfactory system that underlie this process of sensory construction, emphasizing the distinct architectures and properties of the two prominent computational layers in the olfactory bulb. Notably, while the olfactory system solves essentially similar conceptual problems to other sensory systems, such as contrast enhancement, activity normalization, and extending dynamic range, its peculiarities often require qualitatively different computational algorithms than are deployed in other sensory modalities. In particular, the olfactory modality is intrinsically high dimensional, and lacks a simple, externally defined basis analogous to wavelength or pitch on which elemental odor stimuli can be quantitatively compared. Accordingly, the quantitative similarities of the receptive fields of different odorant receptors (ORs) vary according to the statistics of the odor environment. To resolve these unusual challenges, the olfactory bulb appears to utilize unique nontopographical computations and intrinsic learning mechanisms to perform the necessary high-dimensional, similarity-dependent computations. In sum, the early olfactory system implements a coordinated set of early sensory transformations directly analogous to those in other sensory systems, but accomplishes these with unique circuit architectures adapted to the properties of the olfactory modality.

  2. Neuronal circuits and computations: pattern decorrelation in the olfactory bulb.

    Science.gov (United States)

    Friedrich, Rainer W; Wiechert, Martin T

    2014-08-01

    Neuronal circuits in the olfactory bulb transform odor-evoked activity patterns across the input channels, the olfactory glomeruli, into distributed activity patterns across the output neurons, the mitral cells. One computation associated with this transformation is a decorrelation of activity patterns representing similar odors. Such a decorrelation has various benefits for the classification and storage of information by associative networks in higher brain areas. Experimental results from adult zebrafish show that pattern decorrelation involves a redistribution of activity across the population of mitral cells. These observations imply that pattern decorrelation cannot be explained by a global scaling mechanism but that it depends on interactions between distinct subsets of neurons in the network. This article reviews insights into the network mechanism underlying pattern decorrelation and discusses recent results that link pattern decorrelation in the olfactory bulb to odor discrimination behavior.

  3. Relation of the volume of the olfactory bulb to psychophysical measures of olfactory function.

    Science.gov (United States)

    Mazal, Patricia Portillo; Haehner, Antje; Hummel, Thomas

    2016-01-01

    The aim of this review is to investigate whether changes in olfactory bulb volume relate to changes in specific olfactory functions. We studied currently available peer-reviewed articles on the volume of the human olfactory bulb that also included a psychophysical measure of olfactory function. In the present review, we observed a very clear and consistent correlation between general olfactory function and olfactory bulb (OB) volume. We were not able to find a clear relationship between a specific smell component and OB volume, even when analyzing pathologic conditions separately. In some cases, changes were observed for different subtests, but these changes did not significantly correlate with OB volume or had only a borderline correlation. In other cases, we found contradictory data. Several factors may contribute to the difficulties in finding correlations with the different components of smell: (1) the OB volume may be influenced by information from olfactory receptor neurons (bottom-up effect), information from central nervous system (top-down effect) and by direct damage; (2) most pathologic conditions affect more than one area of the olfactory pathway; (3) small sample sizes of hyposmic subjects were used. We believe that it is necessary to do further studies with larger numbers of subjects to answer the currently investigated question.

  4. Odor recognition and segmentation by coupled olfactory bulb and cortical networks

    CERN Document Server

    Li, Z; Li, Zhaoping; Hertz, John

    1999-01-01

    We present a model of a coupled system of the olfactory bulb and cortex. Odor inputs to the epithelium are transformed to oscillatory bulbar activities. The cortex recognizes the odor by resonating to the bulbar oscillating pattern when the amplitude and phase patterns from the bulb match an odor memory stored in the intracortical synapses. We assume a cortical structure which transforms the odor information in the oscillatory pattern to a slow DC feedback signal to the bulb. This feedback suppresses the bulbar response to the pre-existing odor, allowing subsequent odor objects to be segmented out for recognition.

  5. The source of spontaneous activity in the main olfactory bulb of the rat.

    Directory of Open Access Journals (Sweden)

    Josif Stakic

    Full Text Available INTRODUCTION: In vivo, most neurons in the main olfactory bulb exhibit robust spontaneous activity. This paper tests the hypothesis that spontaneous activity in olfactory receptor neurons drives much of the spontaneous activity in mitral and tufted cells via excitatory synapses. METHODS: Single units were recorded in vivo from the main olfactory bulb of a rat before, during, and after application of lidocaine to the olfactory nerve. The effect of lidocaine on the conduction of action potentials from the olfactory epithelium to the olfactory bulb was assessed by electrically stimulating the olfactory nerve rostral to the application site and monitoring the field potential evoked in the bulb. RESULTS: Lidocaine caused a significant decrease in the amplitude of the olfactory nerve evoked field potential that was recorded in the olfactory bulb. By contrast, the lidocaine block did not significantly alter the spontaneous activity of single units in the bulb, nor did it alter the field potential evoked by electrical stimulation of the lateral olfactory tract. Lidocaine block also did not change the temporal patters of action potential or their synchronization with respiration. CONCLUSIONS: Spontaneous activity in neurons of the main olfactory bulb is not driven mainly by activity in olfactory receptor neurons despite the extensive convergence onto mitral and tufted cells. These results suggest that spontaneous activity of mitral and tufted is either an inherent property of these cells or is driven by centrifugal inputs to the bulb.

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

    Science.gov (United States)

    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.

  7. Olfactory bulb size, odor discrimination and magnetic insensitivity in hummingbirds.

    Science.gov (United States)

    Ioalé, P; Papi, F

    1989-05-01

    Relative olfactory bulb size with respect to telencephalic hemispheres (olfactory ratio) was measured in five species of hummingbirds. Trochiliformes were found to be next to last among 25 avian orders with respect to olfactory bulb development. One hummingbird species, the White-vented Violetear (Colibri serrirostris), was trained in a successive go/no-go discrimination task, and learned to feed or not to feed from a container dependent on the olfactory stimuli associated with it. Test birds learned to discriminate amyl acetate vs. turpentine essence, jasmine essence vs. lavender essence, eucalyptus essence vs. no odor, beta-ionone vs. no odor, carvone vs. eucalyptol. In contrast, 1-phenylethanol vs. beta-ionone discrimination, two odorants which appear similar to humans, was unsuccessful. Using a similar procedure, attempts were made to condition a White-vented Violetear and a Versicolored Emerald (Amazilia versicolor) to magnetic stimuli. The birds were unable to discriminate between a normal field and an oscillating field (square wave, 1 Hz, amplitude +/- 0.40 G).

  8. Centrifugal telencephalic afferent connections to the main and accessory olfactory bulbs

    Directory of Open Access Journals (Sweden)

    Alicia eMohedanoMoriano

    2012-05-01

    Full Text Available Parallel to the olfactory system, most mammals possess an accessory olfactory or vomeronasal system. The olfactory and vomeronasal epithelia project to the main and accessory olfactory bulbs, which in turn project to adjacent areas of the telencephalon, respectively. New data indicate that projections arising from the main and accessory olfactory bulbs partially converge in the rostral telencephalon and are non-overlapping at caudal telencephalic levels. Therefore, the basal telencephalon should be reclassified in olfactory, vomeronasal and mixed areas. On the other hand, it has been demonstrated that virtually all olfactory- and vomeronasal-recipient structures send reciprocal projections to the main and accessory olfactory bulbs, respectively. Further, non-chemosensory recipient structures also projects centrifugally to the olfactory bulbs. These feed-back projections appear to be essential modulating processing of chemosensory information. The present work aims at characterizing centrifugal projections to the main and accessory olfactory bulbs arising from olfactory, vomeronasal, mixed and non-chemosensory recipient telencephalic areas. This issue has been addressed by using tracer injections in the rat and mouse brain. Tracer injections were delivered into the main and accessory olfactory bulbs as well as in olfactory, vomeronasal, mixed and non-chemosensory recipient telencephalic structures. The results confirm that olfactory- and vomeronasal-recipient structures project to the main and accessory olfactory bulbs, respectively. Interestingly, olfactory (e.g., piriform cortex, vomeronasal (e.g., posteromedial cortical amygdala, mixed (e.g., the medial amygdala and non-chemosensory-recipient (e.g., the nucleus of the diagonal band structures project to the main and to the accessory olfactory bulbs thus providing the possibility of simultaneous modulation and interaction of both systems at different stages of chemosensory processing.

  9. Centrifugal telencephalic afferent connections to the main and accessory olfactory bulbs

    Science.gov (United States)

    Mohedano-Moriano, Alicia; de la Rosa-Prieto, Carlos; Saiz-Sanchez, Daniel; Ubeda-Bañon, Isabel; Pro-Sistiaga, Palma; de Moya-Pinilla, Miguel; Martinez-Marcos, Alino

    2012-01-01

    Parallel to the olfactory system, most mammals possess an accessory olfactory or vomeronasal system. The olfactory and vomeronasal epithelia project to the main and accessory olfactory bulbs, which in turn project to adjacent areas of the telencephalon, respectively. New data indicate that projections arising from the main and accessory olfactory bulbs partially converge in the rostral telencephalon and are non-overlapping at caudal telencephalic levels. Therefore, the basal telencephalon should be reclassified in olfactory, vomeronasal, and mixed areas. On the other hand, it has been demonstrated that virtually all olfactory- and vomeronasal-recipient structures send reciprocal projections to the main and accessory olfactory bulbs, respectively. Further, non-chemosensory recipient structures also projects centrifugally to the olfactory bulbs. These feed-back projections appear to be essential modulating processing of chemosensory information. The present work aims at characterizing centrifugal projections to the main and accessory olfactory bulbs arising from olfactory, vomeronasal, mixed, and non-chemosensory recipient telencephalic areas. This issue has been addressed by using tracer injections in the rat and mouse brain. Tracer injections were delivered into the main and accessory olfactory bulbs as well as in olfactory, vomeronasal, mixed, and non-chemosensory recipient telencephalic structures. The results confirm that olfactory- and vomeronasal-recipient structures project to the main and accessory olfactory bulbs, respectively. Interestingly, olfactory (e.g., piriform cortex), vomeronasal (e.g., posteromedial cortical amygdala), mixed (e.g., the anterior medial amygdaloid nucleus), and non-chemosensory-recipient (e.g., the nucleus of the diagonal band) structures project to the main and to the accessory olfactory bulbs thus providing the possibility of simultaneous modulation and interaction of both systems at different stages of chemosensory processing

  10. Volumetric study of the olfactory bulb in patients with chronic rhinonasal sinusitis using MRI

    Directory of Open Access Journals (Sweden)

    Reda A. Alarabawy

    2016-06-01

    Conclusions: MRI with volumetric analysis is a useful tool in assessment of the olfactory bulb volume in patients with olfactory loss and appears to be of help in assessment of the degree of recovery in patients after sinus surgery.

  11. Timescale-dependent shaping of correlation by olfactory bulb lateral inhibition.

    Science.gov (United States)

    Giridhar, Sonya; Doiron, Brent; Urban, Nathaniel N

    2011-04-05

    Neurons respond to sensory stimuli by altering the rate and temporal pattern of action potentials. These spike trains both encode and propagate information that guides behavior. Local inhibitory networks can affect the information encoded and propagated by neurons by altering correlations between different spike trains. Correlations introduce redundancy that can reduce encoding but also facilitate propagation of activity to downstream targets. Given this trade-off, how can networks maximize both encoding and propagation efficacy? Here, we examine this problem by measuring the effects of olfactory bulb inhibition on the pairwise statistics of mitral cell spiking. We evoked spiking activity in the olfactory bulb in vitro and measured how lateral inhibition shapes correlations across timescales. We show that inhibitory circuits simultaneously increase fast correlation (i.e., synchrony increases) and decrease slow correlation (i.e., firing rates become less similar). Further, we use computational models to show the benefits of fast correlation/slow decorrelation in the context of odor coding. Olfactory bulb inhibition enhances population-level discrimination of similar inputs, while improving propagation of mitral cell activity to cortex. Our findings represent a targeted strategy by which a network can optimize the correlation structure of its output in a dynamic, activity-dependent manner. This trade-off is not specific to the olfactory system, but rather our work highlights mechanisms by which neurons can simultaneously accomplish multiple, and sometimes competing, aspects of sensory processing.

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

    Directory of Open Access Journals (Sweden)

    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.

  13. Serotonin increases synaptic activity in olfactory bulb glomeruli.

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  15. Odor Memory Stability after Reinnervation of the Olfactory Bulb

    Science.gov (United States)

    Blanco-Hernández, Eduardo; Valle-Leija, Pablo; Zomosa-Signoret, Viviana; Drucker-Colín, René; Vidaltamayo, Román

    2012-01-01

    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. PMID:23071557

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

    Directory of Open Access Journals (Sweden)

    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.

  17. Changes in the neural representation of odorants after olfactory deprivation in the adult mouse olfactory bulb.

    Science.gov (United States)

    Kass, Marley D; Pottackal, Joseph; Turkel, Daniel J; McGann, John P

    2013-01-01

    Olfactory sensory deprivation during development has been shown to induce significant alterations in the neurophysiology of olfactory receptor neurons (ORNs), the primary sensory inputs to the brain's olfactory bulb. Deprivation has also been shown to alter the neurochemistry of the adult olfactory system, but the physiological consequences of these changes are poorly understood. Here we used in vivo synaptopHluorin (spH) imaging to visualize odorant-evoked neurotransmitter release from ORNs in adult transgenic mice that underwent 4 weeks of unilateral olfactory deprivation. Deprivation reduced odorant-evoked spH signals compared with sham-occluded mice. Unexpectedly, this reduction was equivalent between ORNs on the open and plugged sides. Changes in odorant selectivity of glomerular subpopulations of ORNs were also observed, but only in ORNs on the open side of deprived mice. These results suggest that naris occlusion in adult mice produces substantial changes in primary olfactory processing which may reflect not only the decrease in olfactory stimulation on the occluded side but also the alteration of response properties on the intact side. We also observed a modest effect of true sham occlusions that included noseplug insertion and removal, suggesting that conventional noseplug techniques may have physiological effects independent of deprivation per se and thus require more careful controls than has been previously appreciated.

  18. Dendrodendritic Synapses in the Mouse Olfactory Bulb External Plexiform Layer

    Science.gov (United States)

    Bartel, Dianna L.; Rela, Lorena; Hsieh, Lawrence; Greer, Charles A.

    2014-01-01

    Odor information relayed by olfactory bulb projection neurons, mitral and tufted cells (M/T), is modulated by pairs of reciprocal dendrodendritic synaptic circuits in the external plexiform layer (EPL). Interneurons, which are accounted for largely by granule cells, receive depolarizing input from M/T dendrites and in turn inhibit current spread in M/T dendrites via hyperpolarizing reciprocal dendrodendritic synapses. Because the location of dendrodendritic synapses may significantly affect the cascade of odor information, we assessed synaptic properties and density within sublaminae of the EPL and along the length of M/T secondary dendrites. In electron micrographs the M/T to granule cell synapse appeared to predominate and were equivalent in both the outer and inner EPL. However, the dendrodendritic synapses from granule cell spines onto M/T dendrites, were more prevalent in the outer EPL. In contrast, individual gephyrin-IR puncta, a postsynaptic scaffolding protein at inhibitory synapses used here as a proxy for the granule to M/T dendritic synapse was equally distributed throughout the EPL. Of significance to the organization of intrabulbar circuits, gephyrin-IR synapses are not uniformly distributed along M/T secondary dendrites. Synaptic density, expressed as a function of surface area, increases distal to the cell body. Furthermore, the distributions of gephyrin-IR puncta are heterogeneous and appear as clusters along the length of the M/T dendrites. Consistent with computational models, our data suggest that temporal coding in M/T cells is achieved by precisely located inhibitory input and that distance from the soma is compensated with an increase in synaptic density. PMID:25420934

  19. Reduction in subventricular zone-derived olfactory bulb neurogenesis in a rat model of Huntington's disease is accompanied by striatal invasion of neuroblasts.

    Directory of Open Access Journals (Sweden)

    Mahesh Kandasamy

    Full Text Available Huntington's disease (HD is an inherited progressive neurodegenerative disorder caused by an expanded CAG repeat in exon 1 of the huntingtin gene (HTT. The primary neuropathology of HD has been attributed to the preferential degeneration of medium spiny neurons (MSN in the striatum. Reports on striatal neurogenesis have been a subject of debate; nevertheless, it should be considered as an endogenous attempt to repair the brain. The subventricular zone (SVZ might offer a close-by region to supply the degenerated striatum with new cells. Previously, we have demonstrated that R6/2 mice, a widely used preclinical model representing an early onset HD, showed reduced olfactory bulb (OB neurogenesis but induced striatal migration of neuroblasts without affecting the proliferation of neural progenitor cell (NPCs in the SVZ. The present study revisits these findings, using a clinically more relevant transgenic rat model of late onset HD (tgHD rats carrying the human HTT gene with 51 CAG repeats and mimicking many of the neuropathological features of HD seen in patients. We demonstrate that cell proliferation is reduced in the SVZ and OB of tgHD rats compared to WT rats. In the OB of tgHD rats, although cell survival was reduced, the frequency of neuronal differentiation was not altered in the granule cell layer (GCL compared to the WT rats. However, an increased frequency of dopamenergic neuronal differentiation was noticed in the glomerular layer (GLOM of tgHD rats. Besides this, we observed a selective proliferation of neuroblasts in the adjacent striatum of tgHD rats. There was no evidence for neuronal maturation and survival of these striatal neuroblasts. Therefore, the functional role of these invading neuroblasts still needs to be determined, but they might offer an endogenous alternative for stem or neuronal cell transplantation strategies.

  20. 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.

  1. Olfactory consciousness and gamma oscillation couplings across the olfactory bulb, olfactory cortex, and orbitofrontal cortex

    OpenAIRE

    Kensaku eMori; Hiroyuki eManabe; Kimiya eNarikiyo; Naomi eOnisawa

    2013-01-01

    The orbitofrontal cortex receives multi-modality sensory inputs, including olfactory input, and is thought to be involved in conscious perception of the olfactory image of objects. Generation of olfactory consciousness requires neuronal circuit mechanisms for the ‘binding’ of distributed neuronal activities, with each constituent neuron representing a specific component of an olfactory percept. The shortest neuronal pathway for odor signals to reach the orbitofrontal cortex is olfactory senso...

  2. Visualizing olfactory learning functional imaging of experience-induced olfactory bulb changes.

    Science.gov (United States)

    Fletcher, Max L; Bendahmane, Mounir

    2014-01-01

    The anatomical organization of sensory neuron input allows odor information to be transformed into odorant-specific spatial maps of mitral/tufted cell glomerular activity. In other sensory systems, neuronal representations of sensory stimuli can be reorganized or enhanced following learning or experience. Similarly, several studies have demonstrated both structural and physiological experience-induced changes throughout the olfactory system. As experience-induced changes within this circuit likely serve as an initial site for odor memory formation, the olfactory bulb is an ideal site for optical imaging studies of olfactory learning, as they allow for the visualization of experience-induced changes in the glomerular circuit following learning and how these changes impact of odor representations with the bulb. Presently, optical imaging techniques have been used to visualize experience-induced changes in glomerular odor representations in a variety of paradigms in short-term habituation, chronic odor exposure, and olfactory associative conditioning. © 2014 Elsevier B.V. All rights reserved.

  3. The olfactory bulb structure of African giant rat (Cricetomys gambianus, Waterhouse 1840) I: cytoarchitecture.

    Science.gov (United States)

    Olude, M A; Ogunbunmi, T K; Olopade, J O; Ihunwo, A O

    2014-09-01

    The olfactory system typically consists of two parallel systems: the main olfactory system and the accessory olfactory system. The main olfactory bulb (MOB) acts as the initial processing site for volatile chemical stimuli and receives input from the olfactory receptor cells located in the olfactory epithelium. The African giant rat is reputed to have abilities to detect landmines and tuberculosis samples by sniffing. This study therefore is a preliminary study on the histological and immunohistochemical anatomy of the olfactory bulb of the African giant rat (Cricetomys gambianus, Waterhouse). Nissl and Klüver-Barrera histological staining of the olfactory bulb revealed a cytoarchitecture typical of most mammals with 6 cell layers, and 1-2-layered glomeruli measuring approximately 150 μm each in diameter. Immunohistochemical staining with glial fibrillary acidic protein (GFAP) and 2',3'-cyclic nucleotide 3-phosphodiesterase (CNPase) revealed cellular conformations relative to most mammals. GFAP immunohistochemistry also revealed cell bodies and processes within the periglomerular area which may potentiate signaling from the olfactory receptor cells, while CNPase largely showed soma and evidence of myelin sheath deposition, confirming myelination at different layers of the bulb. Neurogenesis was examined using the neurogenic markers doublecortin (DCX) and Ki-67. Migration of newly generated cells was observed in all layers of the MOB with DCX and in most layers with Ki-67. The anatomy of the olfactory bulb is described as relatively large in the African giant rat, having a neuroarchitecture similar to most rodents.

  4. Structure and diversity in mammalian accessory olfactory bulb.

    Science.gov (United States)

    Meisami, E; Bhatnagar, K P

    1998-12-15

    The accessory olfactory bulb (AOB) is the first neural integrative center for the olfactory-like vomeronasal sensory system. In this article, we first briefly present an overview of vomeronasal system organization and review the history of the discovery of mammalian AOB. Next, we briefly review the evolution of the vomeronasal system in vertebrates, in particular the reptiles. Following these introductory aspects, the structure of the rodent AOB, as typical of the well-developed mammalian AOB, is presented, detailing laminar organization and cell types as well as aspects of the homology with the main olfactory bulb. Then, the evolutionary origin and diversity of the AOB in mammalian orders and species is discussed, describing structural, phylogenetic, and species-specific variation in the AOB location, shape, and size and morphologic differentiation and development. The AOB is believed to be absent in fishes but present in terrestrial tetrapods including amphibians; among the reptiles AOB is absent in crocodiles, present in turtles, snakes, and some lizards where it may be as large or larger than the main bulb. The AOB is absent in bird and in the aquatic mammals (whales, porpoises, manatees). Among other mammals, AOB is present in the monotremes and marsupials, edentates, and in the majority of the placental mammals like carnivores, herbivores, as well as rodents and lagomorphs. Most bat species do not have an AOB and among those where one is found, it shows marked variation in size and morphologic development. Among insectivores and primates, AOB shows marked variation in occurrence, size, and morphologic development. It is small in shrews and moles, large in hedgehogs and prosimians; AOB continues to persist in New World monkeys but is not found in the adults of the higher primates such as the Old World monkeys, apes, and humans. In many species where AOB is absent in the adult, it often develops in the embryo and fetus but regresses in later stages of

  5. Preliminary Modeling and Simulation Study on Olfactory Cell Sensation

    Science.gov (United States)

    Zhou, Jun; Yang, Wei; Chen, Peihua; Liu, Qingjun; Wang, Ping

    2009-05-01

    This paper introduced olfactory sensory neuron's whole-cell model with a concrete voltage-gated ionic channels and simulation. Though there are many models in olfactory sensory neuron and olfactory bulb, it remains uncertain how they express the logic of olfactory information processing. In this article, the olfactory neural network model is also introduced. This model specifies the connections among neural ensembles of the olfactory system. The simulation results of the neural network model are consistent with the observed olfactory biological characteristics such as 1/f-type power spectrum and oscillations.

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

    Science.gov (United States)

    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.

  7. Synaptic Inhibition in the Olfactory Bulb Accelerates Odor Discrimination in Mice

    National Research Council Canada - National Science Library

    Abraham, Nixon M; Egger, Veronica; Shimshek, Derya R; Renden, Robert; Fukunaga, Izumi; Sprengel, Rolf; Seeburg, Peter H; Klugmann, Matthias; Margrie, Troy W; Schaefer, Andreas T; Kuner, Thomas

    2010-01-01

    ... translate into behavioral performance. In the olfactory bulb, inhibition of mitral/tufted cells via granule cells may contribute to odor discrimination behavior by refining neuronal representations of odors...

  8. Diversity in olfactory bulb size in birds reflects allometry, ecology and phylogeny

    Directory of Open Access Journals (Sweden)

    Jeremy Richard Corfield

    2015-07-01

    Full Text Available The relative size of olfactory bulbs is correlated with olfactory capabilities across vertebrates and is widely used to assess the relative importance of olfaction to a species’ ecology. In birds, variations in the relative size of olfactory bulbs are correlated with some behaviors, however, the factors that have led to the high level of diversity seen in olfactory bulb sizes across birds are still not well understood. In this study, we use the relative size of olfactory bulbs as a neuroanatomical proxy for olfactory capabilities in 135 species of birds, representing 21 orders. We examine the scaling of olfactory bulbs with brain size across avian orders, determined likely ancestral states and test for correlations between OB sizes and habitat, ecology and behavior. The size of avian OBs varied with the size of the brain and this allometric relationship was for the most part isometric, although species did deviate from this trend. Large olfactory bulbs were characteristic of more basal species and in more recently derived species the OBs were small. Living and foraging in a semi aquatic environment was the strongest variable driving the evolution of large olfactory bulbs in birds; olfaction may provide cues for navigation and foraging in this otherwise featureless environment. Some of the diversity in OB sizes was also undoubtedly due to differences in migratory behavior, foraging strategies and social structure. In summary, relative OB size in birds reflect allometry, phylogeny and behavior in ways that parallel that of other vertebrate classes. This provides comparative evidence that supports recent experimental studies into avian olfaction and suggests that olfaction is a critically important sensory modality for all avian species.

  9. Organisation and chemical neuroanatomy of the African elephant (Loxodonta africana) olfactory bulb.

    Science.gov (United States)

    Ngwenya, Ayanda; Patzke, Nina; Ihunwo, Amadi O; Manger, Paul R

    2011-11-01

    The olfactory system of mammals can be divided into a main and accessory olfactory system with initial processing for each system occurring in the olfactory bulb. The main and accessory olfactory bulbs have similar structural features, even though they appear to be functionally independent. In mammals the main olfactory bulb (MOB) is also one of two established sites of lifelong generation of new cells. The present study describes the histological and immunohistochemical neuroanatomy of the olfactory bulb of the African elephant (Loxodonta africana). The morphology of MOB of the elephant does not differ significantly from that described in other mammals; however, it lacks the internal plexiform layer. In addition, the glomeruli of the glomerular layer are organised in 2-4 "honey-combed" layers, a feature not commonly observed. The cell types and structures revealed with immunohistochemical stains (parvalbumin, calbindin, calretinin, tyrosine hydroxylase, orexin-A, glial fibrillary acidic protein) were similar to other mammals. Neurogenesis was examined using the neurogenic marker doublecortin. Migration of newly generated cells was observed in most layers of the MOB. No accessory olfactory bulb (AOB) was observed. Based on the general anatomy and the immunohistochemical observations, it is evident that the morphology of the African elephant MOB is, for the most part, similar to that of all mammals, although very large in absolute size.

  10. An arterially perfused nose-olfactory bulb preparation of the rat.

    Science.gov (United States)

    Pérez de los Cobos Pallarés, Fernando; Stanić, Davor; Farmer, David; Dutschmann, Mathias; Egger, Veronica

    2015-09-01

    A main feature of the mammalian olfactory bulb network is the presence of various rhythmic activities, in particular, gamma, beta, and theta oscillations, with the latter coupled to the respiratory rhythm. Interactions between those oscillations as well as the spatial distribution of network activation are likely to determine olfactory coding. Here, we describe a novel semi-intact perfused nose-olfactory bulb-brain stem preparation in rats with both a preserved olfactory epithelium and brain stem, which could be particularly suitable for the study of oscillatory activity and spatial odor mapping within the olfactory bulb, in particular, in hitherto inaccessible locations. In the perfused olfactory bulb, we observed robust spontaneous oscillations, mostly in the theta range. Odor application resulted in an increase in oscillatory power in higher frequency ranges, stimulus-locked local field potentials, and excitation or inhibition of individual bulbar neurons, similar to odor responses reported from in vivo recordings. Thus our method constitutes the first viable in situ preparation of a mammalian system that uses airborne odor stimuli and preserves these characteristic features of odor processing. This preparation will allow the use of highly invasive experimental procedures and the application of techniques such as patch-clamp recording, high-resolution imaging, and optogenetics within the entire olfactory bulb.

  11. Culture and purification of human fetal olfactory bulb ensheathing cells

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Objective: To obtain high purity of human fetal olfactory bulb ensheathing cells (OB-hOECs) in vitro and to develop a simple and effective method for primary culture of OB-hOECs. Methods: OB-hOECs were cultured based on the differential rates of attachment of the various harvested cell types. Then the method was combined with arabinoside cytosine (Ara-C)inhibition, serum-free starvation or intermittent neurotrophin 3 (NT3) nutrition method to observe cell states in different cultural environments. The purity of OB-hOECs was assessed with immunocytochemical analysis. Results: OB-hOECs appeared bipolar and tripolar shape, with slender processes forming network. The purity of OECs reached 88% with the selective attachment method on day 6, and then fibroblast proliferated quickly and reduced the purity. When combined with the starvation method, the purity of OECs was 91% on day 6 and 86% on day 9, however, OECs were in a poor state. While combined with the NT3 method, the purity reached 95% on day 9 and 83% on day 12, respectively. The cells still remained in a good state. Conclusion: A combination of selective attachment and intermittent NT3 nutrition is an effective method to obtain OECs with higher purity and quality.

  12. Rapid odor perception in rat olfactory bulb by microelectrode array

    Institute of Scientific and Technical Information of China (English)

    Jun ZHOU; Qi DONG; Liu-jing ZHUANG; Rong LI; Ping WANG

    2012-01-01

    Responses of 302 mitral/tufted (M/T) cells in the olfactory bulb were recorded from 42 anesthetized freely breathing rats using a 16-channel microwire electrode array.Saturated vapors of four pure chemicals,anisole,carvone,citral and isoamyl acetate were applied.After aligning spike trains to the iritial phase of the inhalation after odor onset,the responses of M/T cells showed transient temporal features including excitatory and inhibitory patterns.Both odor-evoked patterns indicated that mammals recognize odors within a short respiration cycle after odor stimulus.Due to the small amount of information received from a single cell,we pooled results from all responsive M/T cells to study the ensemble activity.The firing rates of the cell ensembles were computed over 100 ms bins and population vectors were constructed.The high dimension vectors were condensed into three dimensions for visualization using principal component analysis.The trajectories of both excitatory and inhibitory cell ensembles displayed strong dynamics during odor stimulation.The distances among cluster centers were enlarged compared to those of the resting state.Thus,we presumed that pictures of odor information sent to higher brain regions were depicted and odor discrimination was completed within the first breathing cycle.

  13. 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.

  14. Histone acetylation in the olfactory bulb of young rats facilitates aversive olfactory learning and synaptic plasticity.

    Science.gov (United States)

    Wang, Y-J; Okutani, F; Murata, Y; Taniguchi, M; Namba, T; Kaba, H

    2013-03-01

    Epigenetic mechanisms play an important role in memory formation and synaptic plasticity. Specifically, histone-associated heterochromatin undergoes changes in structure during the early stages of long-term memory formation. In keeping with the classical conditioning paradigm, young rats have been shown to exhibit aversion to an odor stimulus initially presented during foot shock. We previously showed that synaptic plasticity at the dendrodendritic synapses between mitral and granule cells in the olfactory bulb (OB) underlies this aversive olfactory learning. However, the epigenetic mechanisms involved are not well characterized. Therefore, we examined whether intrabulbar infusion of trichostatin A (TSA), a histone deacetylase inhibitor, facilitates olfactory learning in young rats. TSA infusion during odor-shock training enhanced a conditioned odor aversion in a dose-dependent manner and prolonged the learned aversion. Western blot and immunohistochemical analyses showed that the level of histone H4 acetylation significantly increased until 4 h after odor-shock training in both mitral and granule cells in the OB, whereas histone H3 acetylation returned to the control level at 2 h after the training. We also obtained evidence that TSA infusion elevated acetylation of histone H4 or H3. Furthermore, in vitro electrophysiological analysis using slices of the OB revealed that application of TSA significantly enhanced the long-term potentiation induced in synaptic transmission from mitral to granule cells at dendrodendritic synapses. Taken together, these results provide evidence that histone H4 and H3 acetylation in the OB is an epigenetic mechanism associated with aversive olfactory learning in young rats.

  15. Olfactory bulb and retrobulbar regions in the hedgehog tenrec: organization and interconnections.

    Science.gov (United States)

    Radtke-Schuller, S; Künzle, H

    2000-08-01

    The Madagascan lesser hedgehog tenrec (Echinops telfairi) is a terrestrial, nocturnal insectivore with a low encephalization index and a huge olfactory bulb. To gain insight into the organization and evolution of olfactory regions in placental mammals, the cytoarchitecture (Nissl), neurochemical attributes [zinc and acetylcholinesterase stain, nicotinamide adenine dinucleotide phosphate (NADPh)-diaphorase, and calcium-binding proteins], and interconnections (injections of wheat germ agglutinin-horseradish peroxidase and biotinylated dextran amine) of tenrec bulbar and retrobulbar regions were examined. The tenrec has a well-laminated main olfactory bulb, and modified (atypical) glomeruli are found that, to date, have been demonstrated only in murine rodents. Compared with the main olfactory bulb, the accessory bulb is relatively small, with clearly different staining characteristics, particularly with respect to NADPh-diaphorase, anticalbindin, and anticalretinin. External and central anterior olfactory nuclei also show characteristic cytoarchitectural and chemoarchitectural features. The medial olfactory peduncle seems to differ considerably from that in rodents. A small taenial structure can be separated from the hippocampal continuation. This taenia tecti presumably corresponds to the superior part of the tenia tecti in rodents, but no homologue of the rodent's prominent inferior taenia tecti could be found. The connections of bulbar and retrobulbar regions are similar to those seen in other mammals. Interbulbar projection systems connect the two olfactory bulbs through an external (topographic) and central (nontopographic) anterior nucleus; however, the topographic arrangement of the intrabulbar association system seems to differ from that seen in rodents. A reciprocity of direct olfactory bulb connections with the frontal (sulcal/orbital) cortex was found in the tenrec that has not been reported so far in other species.

  16. 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

  17. Comparison of social interaction and neural activation in the main olfactory bulb and the accessory olfactory bulb between Microtus mandarinus and Microtus fortis

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    Fadao TAI, Wanying WANG, Hugh BRODERS, Ruyong SUN, Limin LIU , Hongyuan WANG

    2009-08-01

    Full Text Available To gain insight into the function of AOB and MOB during different social interaction and in different vole species, the behaviors and neural activation of the olfactory bulbs in social interactions of mandarin voles Microtus mandarinus and reed voles Microtus fortis were compared in the present research. Mandarin voles spent significantly more time attacking and sniffing its opponent and sniffing sawdust than reed voles. During same sex encounters, mandarin voles attacked its opponent for a significantly longer time and sniffed its opponent for shorter time compared with male-female interactions. However, no significant behavioral differences were found during encounters of two individual reed voles, regardless of gender composition of the pair. Using c-Fos as an indicator of neural activation, we observed that neural activation was significantly higher in almost all sub-regions of the main olfactory bulb (MOB and the accessory olfactory bulb (AOB of mandarin voles compared with reed voles. Numbers of c-Fos-ir neurons in almost all sub-regions of the AOB and the MOB during male-female interactions were also higher than those in interactions of the same sex. Anterior-posterior ratios of Fos-ir neurons in the AOBM (AOBMR and the AOBG (AOBGR in male-female interaction were significantly higher than those in interaction of the same sex. The AOBMR of male mandarin voles and reed voles were larger than those of females in male-female interactions. Behavioral patterns are consistent with cellular activity patterns. Consistent level of neural activation in MOB and AOB suggests important roles of both the main olfactory bulb and the accessory olfactory bulb in social interaction in two species [Current Zoology 55(4: 279 –287, 2009].

  18. Effects of Human Alpha-Synuclein A53T-A30P Mutations on SVZ and Local Olfactory Bulb Cell Proliferation in a Transgenic Rat Model of Parkinson Disease

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    Faustine Lelan

    2011-01-01

    Full Text Available A transgenic Sprague Dawley rat bearing the A30P and A53T α-synuclein (α-syn human mutations under the control of the tyrosine hydroxylase promoter was generated in order to get a better understanding of the role of the human α-syn mutations on the neuropathological events involved in the progression of the Parkinson’s disease (PD. This rat displayed olfactory deficits in the absence of motor impairments as observed in most early PD cases. In order to investigate the role of the mutated α-syn on cell proliferation, we focused on the subventricular zone (SVZ and the olfactory bulbs (OB as a change of the proliferation could affect OB function. The effect on OB dopaminergic innervation was investigated. The human α-syn co-localized in TH-positive OB neurons. No human α-syn was visualized in the SVZ. A significant increase in resident cell proliferation in the glomerular but not in the granular layers of the OB and in the SVZ was observed. TH innervation was significantly increased within the glomerular layer without an increase in the size of the glomeruli. Our rat could be a good model to investigate the role of human mutated α-syn on the development of olfactory deficits.

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

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    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

  20. Ablation of mouse adult neurogenesis alters olfactory bulb structure and olfactory fear conditioning

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    Matthew Valley

    2009-11-01

    Full Text Available Adult neurogenesis replenishes olfactory bulb (OB interneurons throughout the life of most mammals, yet during this constant fl ux it remains unclear how the OB maintains a constant structure and function. In the mouse OB, we investigated the dynamics of turnover and its impact on olfactory function by ablating adult neurogenesis with an x-ray lesion to the subventricular zone (SVZ. Regardless of the magnitude of the lesion to the SVZ, we found no change in the survival of young adult born granule cells (GCs born after the lesion, and a gradual decrease in the population of GCs born before the lesion. After a lesion producing a 96% reduction of incoming adult born GCs to the OB, we found a diminished behavioral fear response to conditioned odor cues but not to audio cues. Interestingly, despite this behavioral defi cit and gradual anatomical changes, we found no electrophysiological changes in the GC population assayed in vivo through dendro-dendritic synaptic plasticity and odor-evoked local fi eld potential oscillations. These data indicate that turnover in the granule cell layer is generally decoupled from the rate of adult neurogenesis, and that OB adult neurogenesis plays a role in a wide behavioral system extending beyond the OB.

  1. 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

    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...

  2. Activity-induced remodeling of olfactory bulb microcircuits revealed by monosynaptic tracing.

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    Benjamin R Arenkiel

    Full Text Available The continued addition of new neurons to mature olfactory circuits represents a remarkable mode of cellular and structural brain plasticity. However, the anatomical configuration of newly established circuits, the types and numbers of neurons that form new synaptic connections, and the effect of sensory experience on synaptic connectivity in the olfactory bulb remain poorly understood. Using in vivo electroporation and monosynaptic tracing, we show that postnatal-born granule cells form synaptic connections with centrifugal inputs and mitral/tufted cells in the mouse olfactory bulb. In addition, newly born granule cells receive extensive input from local inhibitory short axon cells, a poorly understood cell population. The connectivity of short axon cells shows clustered organization, and their synaptic input onto newborn granule cells dramatically and selectively expands with odor stimulation. Our findings suggest that sensory experience promotes the synaptic integration of new neurons into cell type-specific olfactory circuits.

  3. 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…

  4. Disruption of adult neurogenesis in the olfactory bulb affects social interaction but not maternal behavior

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    Claudia E Feierstein

    2010-12-01

    Full Text Available Adult-born neurons arrive to the olfactory bulb and integrate into the existing circuit throughout life. Despite the prevalence of this phenomenon, its functional impact is still poorly understood. Recent studies point to the importance of newly generated neurons to olfactory learning and memory. Adult neurogenesis is regulated by a variety of factors, notably by instances related to reproductive behavior, such as exposure to mating partners, pregnancy and lactation, and exposure to offspring. To study the contribution of olfactory neurogenesis to maternal behavior and social recognition, here we selectively disrupted olfactory bulb neurogenesis using focal irradiation of the subventricular zone in adult female mice. We show that reduction of olfactory neurogenesis results in an abnormal social interaction pattern with male, but not female, conspecifics; we suggest that this effect could result from inability to detect or discriminate male odors and could therefore have implications for the recognition of potential mating partners. Disruption of olfactory bulb neurogenesis, however, neither impaired maternal-related behaviors, nor did it affect the ability of mothers to discriminate their own progeny from others.

  5. The mannose receptor is expressed by olfactory ensheathing cells in the rat olfactory bulb.

    Science.gov (United States)

    Carvalho, Litia A; Nobrega, Alberto F; Soares, Igor D P; Carvalho, Sergio L; Allodi, Silvana; Baetas-da-Cruz, Wagner; Cavalcante, Leny A

    2013-12-01

    Complex carbohydrate structures are essential molecules of infectious bacteria, parasites, and host cells and are involved in cell signaling associated with immune responses, glycoprotein homeostasis, and cell migration. The uptake of mannose-tailed glycans is usually carried out by professional phagocytes to trigger MHC class I- and MHC class II-restricted antigen presentation or, alternatively, to end inflammation. We have detected the mannose receptor (MR) in cultured olfactory ensheathing cells (OECs), so we investigated by flow cytometry whether recently dissociated cells of the olfactory bulb (OB) nerve fiber layer (ONL) could bind a mannosylated ligand (fluorescein conjugate of mannosyl bovine serum albumin; Man/BSA-FITC) in a specific manner. In addition, we estimated the relative proportion of ONL OECs, microglia, and astrocytes, tagged by 2'3'-cyclic nucleotide 3'-phosphodiesterase (CNPase), by the B4 isolectin of Griffonia simplicifonia (IB4), and by glial fibrillary acidic protein (GFAP), respectively, that were Man/BSA-FITC(+) . We also determined by histochemistry and/or immunohistochemistry whether Man/BSA-FITC or an anti-MR antibody (anti-C-terminal MR peptide; anti-cMR) labeled OECs and/or parenchymal microglia. In addition, we confirmed by Western blot with the K1K2 (against the entire MR molecule) antibody that a band of about 180 kDA is expressed in the OB. Our findings are compatible with a prospective sentinel role of OECs against pathogens of the upper airways and/or damage-associated glycidic patterns as well as with homeostasis of OB mannosylated glycoproteins. Copyright © 2013 Wiley Periodicals, Inc.

  6. Olfactory sensory deprivation increases the number of proBDNF-immunoreactive mitral cells in the olfactory bulb of mice.

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    Biju, K C; Mast, Thomas Gerald; Fadool, Debra Ann

    2008-12-05

    In the olfactory bulb, apoptotic cell-death induced by sensory deprivation is restricted to interneurons in the glomerular and granule cell layers, and to a lesser extent in the external plexiform layer, whereas mitral cells do not typically undergo apoptosis. With the goal to understand whether brain-derived neurotrophic factor (BDNF) mediates mitral cell survival, we performed unilateral naris occlusion on mice at postnatal day one (P1) and examined the subsequent BDNF-immunoreactive (BDNF-ir) profile of the olfactory bulb at P20, P30, and P40. Ipsilateral to the naris occlusion, there was a significant increase in the number of BDNF-ir mitral cells per unit area that was independent of the duration of the sensory deprivation induced by occlusion. The number of BDNF-ir juxtaglomerular cells per unit area, however, was clearly diminished. Western blot analysis revealed the presence of primarily proBDNF in the olfactory bulb. These data provide evidence for a neurotrophic role of proBDNF in the olfactory system of mice and suggest that proBDNF may act to protect mitral cells from the effects of apoptotic changes induced by odor sensory deprivation.

  7. Context-driven activation of odor representations in the absence of olfactory stimuli in the olfactory bulb and piriform cortex.

    Science.gov (United States)

    Mandairon, Nathalie; Kermen, Florence; Charpentier, Caroline; Sacquet, Joelle; Linster, Christiane; Didier, Anne

    2014-01-01

    Sensory neural activity is highly context dependent and shaped by experience and expectation. In the olfactory bulb (OB), the first cerebral relay of olfactory processing, responses to odorants are shaped by previous experiences including contextual information thanks to strong feedback connections. In the present experiment, mice were conditioned to associate an odorant with a visual context and were then exposed to the visual context alone. We found that the visual context alone elicited exploration of the odor port similar to that elicited by the stimulus when it was initially presented. In the OB, the visual context alone elicited a neural activation pattern, assessed by mapping the expression of the immediate early gene zif268 (egr-1) that was highly similar to that evoked by the conditioned odorant, but not other odorants. This OB activation was processed by olfactory network as it was transmitted to the piriform cortex. Interestingly, a novel context abolished neural and behavioral responses. In addition, the neural representation in response to the context was dependent on top-down inputs, suggesting that context-dependent representation is initiated in cortex. Modeling of the experimental data suggests that odor representations are stored in cortical networks, reactivated by the context and activate bulbar representations. Activation of the OB and the associated behavioral response in the absence of physical stimulus showed that mice are capable of internal representations of sensory stimuli. The similarity of activation patterns induced by imaged and the corresponding physical stimulus, triggered only by the relevant context provides evidence for an odor-specific internal representation.

  8. Soft-diet feeding impairs neural transmission between mitral cells and interneurons in the mouse olfactory bulb.

    Science.gov (United States)

    Noguchi, Tomohiro; Utsugi, Chizuru; Kashiwayanagi, Makoto

    2017-07-29

    (Objective) The subventricular zone in mice generates a lot of neuroblasts even during adulthood. These neuroblasts migrate to the olfactory bulb and differentiate into inhibitory interneurons such as granule cells and periglomerular cells. Olfactory sensory neurons receive information from various odorants and transmit it to the olfactory bulb. Our previous study showed that soft-diet feeding impairs neurogenesis in the subventricular zone, in turn leading to the reduction of odor-induced behaviors and Fos-immunoreactivities, the latter of which are markers of neural activity, at the olfactory bulb after exposure to odors. Release of GABA from inhibitory interneurons at the olfactory bulb induces inhibitory currents at the mitral cells, which are output neurons from the olfactory bulb. (Design) In the present study, we measured spontaneous inhibitory postsynaptic currents (sIPSCs) at the mitral cells of mice fed a soft diet in order to explore the effects of changes in texture of diets on neural function at the olfactory bulb. (Results) The soft-diet feeding extended the intervals between sIPSCs and reduced their peak amplitudes. (Conclusions) The present results suggest that soft-diet feeding in mice attenuates the neural functions of inhibitory interneurons at the olfactory bulb. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Trajectory and terminal distribution of single centrifugal axons from olfactory cortical areas in the rat olfactory bulb.

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    Matsutani, S

    2010-08-11

    The olfactory bulb receives a large number of centrifugal fibers whose functions remain unclear. To gain insight into the function of the bulbar centrifugal system, the morphology of individual centrifugal axons from olfactory cortical areas was examined in detail. An anterograde tracer, Phaseolus vulgaris leucoagglutinin, was injected into rat olfactory cortical areas, including the pars lateralis of the anterior olfactory nucleus (lAON) and the anterior part of the piriform cortex (aPC). Reconstruction from serial sections revealed that the extrabulbar segments of centrifugal axons from the lAON and those from the aPC had distinct trajectories: the former tended to innervate the pars externa of the AON before entering the olfactory bulb, while the latter had extrabulbar collaterals that extended to a variety of targets. In contrast to the extrabulbar segments, no clear differences were found between the intrabulbar segments of axons from the lAON and from the aPC. The intrabulbar segments of centrifugal axons were mainly found in the granule cell layer but a few axons extended into the external plexiform and glomerular layer. Approximately 40% of centrifugal axons innervated both the medial and lateral aspects of the olfactory bulb. The number of boutons found on single intrabulbar segments was typically less than 1000. Boutons tended to aggregate and form complex terminal tufts with short axonal branches. Terminal tufts, no more than 10 in single axons from ipsilateral cortical areas, were localized to the granule cell layer with varying intervals; some tufts formed patchy clusters and others were scattered over areas that extended for a few millimeters. The patchy, widespread distribution of terminals suggests that the centrifugal axons are able to couple the activity of specific subsets of bulbar neurons even when the subsets are spatially separated.

  10. Parallel odor processing by two anatomically distinct olfactory bulb target structures.

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    Colleen A Payton

    Full Text Available The olfactory cortex encompasses several anatomically distinct regions each hypothesized to provide differential representation and processing of specific odors. Studies exploring whether or not the diversity of olfactory bulb input to olfactory cortices has functional meaning, however, are lacking. Here we tested whether two anatomically major olfactory cortical structures, the olfactory tubercle (OT and piriform cortex (PCX, differ in their neural representation and processing dynamics of a small set of diverse odors by performing in vivo extracellular recordings from the OT and PCX of anesthetized mice. We found a wealth of similarities between structures, including odor-evoked response magnitudes, breadth of odor tuning, and odor-evoked firing latencies. In contrast, only few differences between structures were found, including spontaneous activity rates and odor signal-to-noise ratios. These results suggest that despite major anatomical differences in innervation by olfactory bulb mitral/tufted cells, the basic features of odor representation and processing, at least within this limited odor set, are similar within the OT and PCX. We predict that the olfactory code follows a distributed processing stream in transmitting behaviorally and perceptually-relevant information from low-level stations.

  11. Synaptic connectivity of the cholinergic axons in the olfactory bulb of the cynomolgus monkey

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    Teresa eLiberia

    2015-03-01

    Full Text Available The olfactory bulb of mammals receives cholinergic afferents from the horizontal limb of the diagonal band of Broca. At present, the synaptic connectivity of the cholinergic axons on the circuits of the olfactory bulb has only been investigated in the rat. In this report, we analyze the synaptic connectivity of the cholinergic axons in the olfactory bulb of the cynomolgus monkey (Macaca fascicularis. Our aim is to investigate whether the cholinergic innervation of the bulbar circuits is phylogenetically conserved between macrosmatic and microsmatic mammals. Our results demonstrate that the cholinergic axons form synaptic contacts on interneurons. In the glomerular layer, their main targets are the periglomerular cells, which receive axo-somatic and axo-dendritic synapses. In the inframitral region, their main targets are the granule cells, which receive synaptic contacts on their dendritic shafts and spines. Although the cholinergic boutons were frequently found in close vicinity of the dendrites of principal cells, we have not found synaptic contacts on them. From a comparative perspective, our data indicate that the synaptic connectivity of the cholinergic circuits is highly preserved in the olfactory bulb of macrosmatic and microsmatic mammals.

  12. Postnatal Developmental Expression of Calbindin, Calretinin and Parvalbumin in Mouse Main Olfactory Bulb

    Institute of Scientific and Technical Information of China (English)

    Zhao-Ping QIN; Shu-Ming YE; Ji-Zeng DU; Gong-Yu SHEN

    2005-01-01

    The distribution of calbindin, calretinin and parvalbumin during the development of the mouse main olfactory bulb (MOB) was studied using immunohistochemistry techniques. The results are as follows:(1) caibindin-immunoreactive profiles were mainly located in the glomerular layer, and few large calbindinimmunoreactive cells were found in the subependymal layer of postnatal day 10 (P10) to postnatal day 40 (P40) mice; (2) no calbindin was detected in the mitral cell layer at any stage; (3) calretinin-immunoreactive profiles were present in all layers of the main olfactory bulb at all stages, especially in the olfactory nerve layer, glomerular layer and granule cell layer; (4) parvalbumin-immunoreactive profiles were mainly located in the external plexiform layer (except for P10 mice); (5) weakly stained parvalbumin-immunoreactive profiles were present in the glomerular layer at all stages; and (6) no parvalbumin was detected in the mitral cell layer at any stage.

  13. Cluster Analysis of the Rat Olfactory Bulb Activity in Response to Different Odorants

    Science.gov (United States)

    Falasconi, M.; Gutierrez, A.; Auffarth, B.; Sberveglieri, G.; Marco, S.

    2009-05-01

    With the goal of deepen in the understanding of coding of chemical information in the olfactory system, a large data set consisting of rat's olfactory bulb activity values in response to several different volatile compounds has been analyzed by fuzzy c-means clustering methods. Clustering should help to discover groups of glomeruli that are similary activated according to their response profiles across the odorants. To investigate the significance of the achieved fuzzy partitions we developed and applied a novel validity approach based on cluster stability. Our results show certain level of glomerular clustering in the olfactory bulb and indicate that exist a main chemo-topic subdivision of the glomerular layer in few macro-area which are rather specific to particular functional groups of the volatile molecules.

  14. Mesenchymal stem cells from rat olfactory bulbs can differentiate into cells with cardiomyocyte characteristics.

    Science.gov (United States)

    Huang, Yuahn-Sieh; Li, I-Hsun; Chueh, Sheau-Huei; Hueng, Dueng-Yuan; Tai, Ming-Cheng; Liang, Chang-Min; Lien, Shiu-Bii; Sytwu, Huey-Kang; Ma, Kuo-Hsing

    2015-12-01

    Mesenchymal stromal/stem cells (MSCs) are widely distributed in different tissues such as bone marrow, adipose tissues, peripheral blood, umbilical cord and amnionic fluid. Recently, MSC-like cells were also found to exist in rat olfactory bulb and are capable of inducing differentiation into mesenchymal lineages - osteocytes, chondrocytes and adipocytes. However, whether these cells can differentiate into myocardial cells is not known. In this study, we examined whether olfactory bulb-derived MSCs could differentiate into myocardial cells in vitro. Fibroblast-like cells isolated from the olfactory bulb of neonatal rats were grown under four conditions: no treatment; in the presence of growth factors (neuregulin-1, bFGF and forskolin); co-cultured with cardiomyocytes; and co-cultured with cardiomyocytes plus neuregulin-1, bFGF and forskolin. Cell differentiation into myocardial cells was monitored by RT-PCR, light microscopy immunofluorescence, western blot analysis and contractile response to pharmacological treatments. The isolated olfactory bulb-derived fibroblast-like cells expressed CD29, CD44, CD90, CD105, CD166 but not CD34 and CD45, consistent with the characteristics of MSCs. Long cylindical cells that spontaneously contracted were only observed following 7 days of co-culture of MSCs with rat cardiomyocytes plus neuregulin-1, bFGF and forskolin. RT-PCR and western blot analysis indicated that the cylindrical cells expressed myocardial markers, such as Nkx2.5, GATA4, sarcomeric α-actinin, cardiac troponin I, cardiac myosin heavy chain, atrial natriuretic peptide and connexin 43. They also contained sarcomeres and gap junction and were sensitive to pharmacological treatments (adrenal and cholinergic agonists and antagonists). These findings indicate that rat olfactory bulb-derived fibroblast-like cells with MSC characteristics can differentiate into myocardial-like cells.

  15. Pharmacological analysis of ionotropic glutamate receptor function in neuronal circuits of the zebrafish olfactory bulb.

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    Rico Tabor

    Full Text Available Although synaptic functions of ionotropic glutamate receptors in the olfactory bulb have been studied in vitro, their roles in pattern processing in the intact system remain controversial. We therefore examined the functions of ionotropic glutamate receptors during odor processing in the intact olfactory bulb of zebrafish using pharmacological manipulations. Odor responses of mitral cells and interneurons were recorded by electrophysiology and 2-photon Ca(2+ imaging. The combined blockade of AMPA/kainate and NMDA receptors abolished odor-evoked excitation of mitral cells. The blockade of AMPA/kainate receptors alone, in contrast, increased the mean response of mitral cells and decreased the mean response of interneurons. The blockade of NMDA receptors caused little or no change in the mean responses of mitral cells and interneurons. However, antagonists of both receptor types had diverse effects on the magnitude and time course of individual mitral cell and interneuron responses and, thus, changed spatio-temporal activity patterns across neuronal populations. Oscillatory synchronization was abolished or reduced by AMPA/kainate and NMDA receptor antagonists, respectively. These results indicate that (1 interneuron responses depend mainly on AMPA/kainate receptor input during an odor response, (2 interactions among mitral cells and interneurons regulate the total olfactory bulb output activity, (3 AMPA/kainate receptors participate in the synchronization of odor-dependent neuronal ensembles, and (4 ionotropic glutamate receptor-containing synaptic circuits shape odor-specific patterns of olfactory bulb output activity. These mechanisms are likely to be important for the processing of odor-encoding activity patterns in the olfactory bulb.

  16. Efferent and afferent connections of the olfactory bulb and prepiriform cortex in the pigeon (Columba livia).

    Science.gov (United States)

    Atoji, Yasuro; Wild, J Martin

    2014-06-01

    Although olfaction in birds is known to be involved in a variety of behaviors, there is comparatively little detailed information on the olfactory brain. In the pigeon brain, the olfactory bulb (OB) is known to project to the prepiriform cortex (CPP), piriform cortex (CPi), and dorsolateral corticoid area (CDL), which together are called the olfactory pallium, but centrifugal pathways to the OB have not been fully explored. Fiber connections of CPi and CDL have been reported, but those of other olfactory pallial nuclei remain unknown. The present study examines the fiber connections of OB and CPP in pigeons to provide a more detailed picture of their connections using tract-tracing methods. When anterograde and retrograde tracers were injected in OB, projections to a more extensive olfactory pallium were revealed, including the anterior olfactory nucleus, CPP, densocellular part of the hyperpallium, tenia tecta, hippocampal continuation, CPi, and CDL. OB projected commissural fibers to the contralateral OB but did not receive afferents from the contralateral olfactory pallium. When tracers were injected in CPP, reciprocal ipsilateral connections with OB and nuclei of the olfactory pallium were observed, and CPP projected to the caudolateral nidopallium and the limbic system, including the hippocampal formation, septum, lateral hypothalamic nucleus, and lateral mammillary nucleus. These results show that the connections of OB have a wider distribution throughout the olfactory pallium than previously thought and that CPP provides a centrifugal projection to the OB and acts as a relay station to the limbic system.

  17. 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.

  18. Retronasal odor concentration coding in glomeruli of the rat olfactory bulb

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    ShreeHari eGautam

    2014-10-01

    Full Text Available The mammalian olfactory system processes odorants presented orthonasally (inhalation through the nose and also retronasally (exhalation, enabling identification of both external as well as internal objects during food consumption. There are distinct differences between ortho- and retronasal air flow patterns, psychophysics, multimodal integration and glomerular responses. Recent work indicates that rats can also detect odors retronasally, that rats can associate retronasal odors with tastes, and that their olfactory bulbs (OBs can respond to retronasal odorants but differently than to orthonasal odors. To further characterize retronasal OB input activity patterns, experiments here focus on determining the effects of odorant concentration on glomerular activity by monitoring calcium activity in the dorsal OB of rats using a dextran-conjugated calcium-sensitive dye in vivo. Results showed reliable concentration-response curves that differed between odorants, and recruitment of additional glomeruli, as odorant concentration increases. We found evidence of different concentration-response functions between glomeruli, that in turn depended on odor. Further, the relation between dynamics and concentration differed remarkably among retronasal odorants. These dynamics are suggested to reduce the odor map ambiguity based on response amplitude. Elucidating the coding of retronasal odor intensity is fundamental to the understanding of feeding behavior and the neural basis of flavor. These data further establish and refine the rodent model of flavor neuroscience.

  19. Retronasal odor concentration coding in glomeruli of the rat olfactory bulb

    Science.gov (United States)

    Gautam, Shree Hari; Short, Shaina M.; Verhagen, Justus V.

    2014-01-01

    The mammalian olfactory system processes odorants presented orthonasally (inhalation through the nose) and also retronasally (exhalation), enabling identification of both external as well as internal objects during food consumption. There are distinct differences between ortho- and retronasal air flow patterns, psychophysics, multimodal integration, and glomerular responses. Recent work indicates that rats can also detect odors retronasally, that rats can associate retronasal odors with tastes, and that their olfactory bulbs (OBs) can respond to retronasal odorants but differently than to orthonasal odors. To further characterize retronasal OB input activity patterns, experiments here focus on determining the effects of odor concentration on glomerular activity by monitoring calcium activity in the dorsal OB of rats using a dextran-conjugated calcium-sensitive dye in vivo. Results showed reliable concentration-response curves that differed between odorants, and recruitment of additional glomeruli, as odor concentration increased. We found evidence of different concentration-response functions between glomeruli, that in turn depended on odor. Further, the relation between dynamics and concentration differed remarkably among retronasal odorants. These dynamics are suggested to reduce the odor map ambiguity based on response amplitude. Elucidating the coding of retronasal odor intensity is fundamental to the understanding of feeding behavior and the neural basis of flavor. These data further establish and refine the rodent model of flavor neuroscience. PMID:25386123

  20. Entorhinal cortex stimulation modulates amygdala and piriform cortex responses to olfactory bulb inputs in the rat.

    Science.gov (United States)

    Mouly, A-M; Di Scala, G

    2006-01-01

    The rodent olfactory bulb sends direct projections to the piriform cortex and to two structures intimately implicated in memory processes, the entorhinal cortex and the amygdala. The piriform cortex has monosynaptic projections with the amygdala and the piriform cortex and is therefore in a position to modulate olfactory input either directly in the piriform cortex, or via the amygdala. In order to investigate this hypothesis, field potential signals induced in anesthetized rats by electrical stimulation of the olfactory bulb or the entorhinal cortex were recorded simultaneously in the piriform cortex (anterior part and posterior part) and the amygdala (basolateral nucleus and cortical nucleus). Single-site paired-pulse stimulation was used to assess the time courses of short-term inhibition and facilitation in each recording site in response to electrical stimulation of the olfactory bulb and entorhinal cortex. Paired-pulse stimulation of the olfactory bulb induced homosynaptic inhibition for short interpulse interpulse intervals (20-30 ms) in all the recording sites, with a significantly lower degree of inhibition in the anterior piriform cortex than in the other structures. At longer intervals (40-80 ms), paired-pulse facilitation was observed in all the structures. Paired-pulse stimulation of the entorhinal cortex mainly resulted in inhibition for the shortest interval duration (20 ms) in anterior piriform cortex, posterior piriform cortex and amygdala basolateral but not cortical nucleus. Double-site paired-pulse stimulation was then applied to determine if stimulation of the entorhinal cortex can modulate responses to olfactory bulb stimulation. For short interpulse intervals (20 ms) heterosynaptic inhibition was observed in anterior piriform cortex, posterior piriform cortex and amygdala basolateral but not cortical nucleus. The level of inhibition was greater in the basolateral nucleus than in the other structures. Taken together these data suggest that the

  1. 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.

  2. 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.

  3. Subtype-specific reduction of olfactory bulb interneurons in Pax6 heterozygous mutant mice.

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    Haba, Hasumi; Nomura, Tadashi; Suto, Fumikazu; Osumi, Noriko

    2009-09-01

    Interneurons in the olfactory bulb (OB) play essential roles in the processing of olfactory information. They are classified into several subpopulations by the expression of different neurochemical markers. Here we focused on a transcription factor Pax6, and examined its expression and function in distinct subtypes of OB interneurons. We identified Pax6 expression in specific subtypes of interneurons in the external plexiform layer (EPL). The number of these interneuron subtypes was dramatically decreased in Pax6 heterozygous mutant mice. These results indicate that Pax6 is required for differentiation and/or maintenance of EPL interneurons in the adult mouse OB.

  4. Cerebral complexity preceded enlarged brain size and reduced olfactory bulbs in Old World monkeys.

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    Gonzales, Lauren A; Benefit, Brenda R; McCrossin, Monte L; Spoor, Fred

    2015-07-03

    Analysis of the only complete early cercopithecoid (Old World monkey) endocast currently known, that of 15-million-year (Myr)-old Victoriapithecus, reveals an unexpectedly small endocranial volume (ECV) relative to body size and a large olfactory bulb volume relative to ECV, similar to extant lemurs and Oligocene anthropoids. However, the Victoriapithecus brain has principal and arcuate sulci of the frontal lobe not seen in the stem catarrhine Aegyptopithecus, as well as a distinctive cercopithecoid pattern of gyrification, indicating that cerebral complexity preceded encephalization in cercopithecoids. Since larger ECVs, expanded frontal lobes, and reduced olfactory bulbs are already present in the 17- to 18-Myr-old ape Proconsul these features evolved independently in hominoids (apes) and cercopithecoids and much earlier in the former. Moreover, the order of encephalization and brain reorganization was apparently different in hominoids and cercopithecoids, showing that brain size and cerebral organization evolve independently.

  5. Mature and Precursor Brain-Derived Neurotrophic Factor Have Individual Roles in the Mouse Olfactory Bulb

    OpenAIRE

    Thomas Gerald Mast; Debra Ann Fadool

    2012-01-01

    BACKGROUND: Sensory deprivation induces dramatic morphological and neurochemical changes in the olfactory bulb (OB) that are largely restricted to glomerular and granule layer interneurons. Mitral cells, pyramidal-like neurons, are resistant to sensory-deprivation-induced changes and are associated with the precursor to brain-derived neurotrophic factor (proBDNF); here, we investigate its unknown function in the adult mouse OB. PRINCIPAL FINDINGS: As determined using brain-slice electrophysio...

  6. Calretinin-Periglomerular Interneurons in Mice Olfactory Bulb: Cells of Few Words

    OpenAIRE

    Alex Fogli Iseppe; Angela Pignatelli; Ottorino Belluzzi

    2016-01-01

    Within the olfactory bulb (OB), periglomerular (PG) cells consist of various types of interneurons, generally classified by their chemical properties such as neurotransmitter and calcium binding proteins.Calretinin (CR) characterizes morphologically and functionally the more numerous and one of the less known subpopulation of PG cells in the OB. Using of transgenic mice expressing eGFP under the CR promoter, we have tried to obtain the first functional characterization of these cells. Electro...

  7. Cerebral complexity preceded enlarged brain size and reduced olfactory bulbs in Old World monkeys

    OpenAIRE

    Gonzales, L.; Benefit, B.; McCrossin, M.; Spoor, F.

    2015-01-01

    Analysis of the only complete early cercopithecoid (Old World monkey) endocast currently known, that of 15-million-year (Myr)-old Victoriapithecus, reveals an unexpectedly small endocranial volume (ECV) relative to body size and a large olfactory bulb volume relative to ECV, similar to extant lemurs and Oligocene anthropoids. However, the Victoriapithecus brain has principal and arcuate sulci of the frontal lobe not seen in the stem catarrhine Aegyptopithecus, as well as a distinctive cercopi...

  8. Gender differences in elements of human anterior commissure and olfactory bulb and tract.

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    Tohno, Setsuko; Ongkana, Nutcharin; Ke, Lining; Mahakkanukrauh, Pasuk; Minami, Takeshi; Suwannahoy, Patipath; Sinthubua, Apichat; Tohno, Yoshiyuki

    2010-10-01

    To examine whether there were gender differences in the various brain regions, the authors investigated the gender differences in seven element contents of the anterior commissure, mammillary body, and olfactory bulb and tract by direct chemical analysis. After ordinary dissection at Nara Medical University was finished, the anterior commissures, mammillary bodies, and olfactory bulbs and tracts were resected from the cerebra cut at median line. The brain samples were treated with 99.5% ethanol three times to remove lipids. After ashing with nitric acid and perchloric acid, the seven element contents Ca, P, S, Mg, Zn, Fe, and Na were determined by inductively coupled plasma-atomic emission spectrometry. It was found that the Zn content was significantly higher in the anterior commissures of men than in those of women. In the olfactory bulbs and tracts, it was found that the Ca, P, and Zn contents were significantly higher in men than in women. In contrast, no significant difference was found between the mammillary bodies of men and women regarding the seven element contents.

  9. Activity patterns elicited by airflow in the olfactory bulb and their possible functions.

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    Wu, Ruiqi; Liu, Yue; Wang, Li; Li, Bo; Xu, Fuqiang

    2017-10-02

    Olfactory sensory neurons (OSNs) can sense both odorants and airflows. In the olfactory bulb (OB), the coding of odor information is well studied, but the coding of mechanical stimulation is rarely investigated. Unlike odor sensing, the functions of airflow sensing of OSNs are also largely unknown. Here, the activity patterns elicited by mechanical airflow in male rat OBs were mapped using fMRI and correlated with local field potential recordings. In an attempt to reveal possible functions of airflow sensing, the relationship between airflow patterns and physiological parameters was also examined. We found that: a) the activity pattern in the OB evoked by airflow in the nasal cavity was more broadly distributed, compared with those evoked by odors; b) the pattern intensity increases with total airflow, while the pattern topography is rather similar; and c) the heart rate, spontaneous respiratory rate, and EEG power in β-band were reduced under regular mechanical airflow, compared with no airflow through the nasal cavity. The mapping results provide evidence that the signals elicited by mechanical airflow in OSNs are transmitted to the OB, and that the OB has the potential to code and process mechanical information. Our functional data indicate that airflow rhythm in the olfactory system is able to regulate the physiological and brain states, providing an explanation for the effects of breath controlling in meditation, yoga, and Taoism practices.Significant statementThe studies about presentation of odor information in the olfactory bulb is comprehensive, while that of breathing features is rare. Here we investigated the global activity patterns in the rat olfactory bulb elicited by airflow in the nasal cavity using BOLD-fMRI for the first time and found that the activity pattern elicited by airflow is broadly distributed, with increasing pattern intensity and similar topography under increasing total airflow. Further, heart rate, spontaneous respiratory rate in

  10. Presynaptic gain control by endogenous cotransmission of dopamine and GABA in the olfactory bulb.

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    Vaaga, Christopher E; Yorgason, Jordan T; Williams, John T; Westbrook, Gary L

    2017-03-01

    In the olfactory bulb, lateral inhibition mediated by local juxtaglomerular interneurons has been proposed as a gain control mechanism, important for decorrelating odorant responses. Among juxtaglomerular interneurons, short axon cells are unique as dual-transmitter neurons that release dopamine and GABA. To examine their intraglomerular function, we expressed channelrhodopsin under control of the DAT-cre promoter and activated olfactory afferents within individual glomeruli. Optical stimulation of labeled cells triggered endogenous dopamine release as measured by cyclic voltammetry and GABA release as measured by whole cell GABAA receptor currents. Activation of short axon cells reduced the afferent presynaptic release probability via D2 and GABAB receptor activation, resulting in reduced spiking in both mitral and external tufted cells. Our results suggest that short axon cells influence glomerular activity not only by direct inhibition of external tufted cells but also by inhibition of afferent inputs to external tufted and mitral cells.NEW & NOTEWORTHY Sensory systems, including the olfactory system, encode information across a large dynamic range, making synaptic mechanisms of gain control critical to proper function. Here we demonstrate that a dual-transmitter interneuron in the olfactory bulb controls the gain of intraglomerular afferent input via two distinct mechanisms, presynaptic inhibition as well as inhibition of a principal neuron subtype, and thereby potently controls the synaptic gain of afferent inputs. Copyright © 2017 the American Physiological Society.

  11. BDNF over-expression increases olfactory bulb granule cell dendritic spine density in vivo.

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    McDole, B; Isgor, C; Pare, C; Guthrie, K

    2015-09-24

    Olfactory bulb granule cells (GCs) are axon-less, inhibitory interneurons that regulate the activity of the excitatory output neurons, the mitral and tufted cells, through reciprocal dendrodendritic synapses located on GC spines. These contacts are established in the distal apical dendritic compartment, while GC basal dendrites and more proximal apical segments bear spines that receive glutamatergic inputs from the olfactory cortices. This synaptic connectivity is vital to olfactory circuit function and is remodeled during development, and in response to changes in sensory activity and lifelong GC neurogenesis. Manipulations that alter levels of the neurotrophin brain-derived neurotrophic factor (BDNF) in vivo have significant effects on dendritic spine morphology, maintenance and activity-dependent plasticity for a variety of CNS neurons, yet little is known regarding BDNF effects on bulb GC spine maturation or maintenance. Here we show that, in vivo, sustained bulbar over-expression of BDNF in transgenic mice produces a marked increase in GC spine density that includes an increase in mature spines on their apical dendrites. Morphometric analysis demonstrated that changes in spine density were most notable in the distal and proximal apical domains, indicating that multiple excitatory inputs are potentially modified by BDNF. Our results indicate that increased levels of endogenous BDNF can promote the maturation and/or maintenance of dendritic spines on GCs, suggesting a role for this factor in modulating GC functional connectivity within adult olfactory circuitry.

  12. 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.

  13. Multimodal imaging of subventricular zone neural stem/progenitor cells in the cuprizone mouse model reveals increased neurogenic potential for the olfactory bulb pathway, but no contribution to remyelination of the corpus callosum.

    Science.gov (United States)

    Guglielmetti, Caroline; Praet, Jelle; Rangarajan, Janaki Raman; Vreys, Ruth; De Vocht, Nathalie; Maes, Frederik; Verhoye, Marleen; Ponsaerts, Peter; Van der Linden, Annemie

    2014-02-01

    Multiple sclerosis is a devastating demyelinating disease of the central nervous system (CNS) in which endogenous remyelination, and thus recovery, often fails. Although the cuprizone mouse model allowed elucidation of many molecular factors governing remyelination, currently very little is known about the spatial origin of the oligodendrocyte progenitor cells that initiate remyelination in this model. Therefore, we here investigated in this model whether subventricular zone (SVZ) neural stem/progenitor cells (NSPCs) contribute to remyelination of the splenium following cuprizone-induced demyelination. Experimentally, from the day of in situ NSPC labeling, C57BL/6J mice were fed a 0.2% cuprizone diet during a 4-week period and then left to recover on a normal diet for 8weeks. Two in situ labeling strategies were employed: (i) NSPCs were labeled by intraventricular injection of micron-sized iron oxide particles and then followed up longitudinally by means of magnetic resonance imaging (MRI), and (ii) SVZ NSPCs were transduced with a lentiviral vector encoding the eGFP and Luciferase reporter proteins for longitudinal monitoring by means of in vivo bioluminescence imaging (BLI). In contrast to preceding suggestions, no migration of SVZ NSPC towards the demyelinated splenium was observed using both MRI and BLI, and further validated by histological analysis, thereby demonstrating that SVZ NSPCs are unable to contribute directly to remyelination of the splenium in the cuprizone model. Interestingly, using longitudinal BLI analysis and confirmed by histological analysis, an increased migration of SVZ NSPC-derived neuroblasts towards the olfactory bulb was observed following cuprizone treatment, indicative for a potential link between CNS inflammation and increased neurogenesis. © 2013.

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

    Science.gov (United States)

    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.

  15. Odor-Induced Neuronal Rhythms in the Olfactory Bulb Are Profoundly Modified in ob/ob Obese Mice

    Science.gov (United States)

    Chelminski, Yan; Magnan, Christophe; Luquet, Serge H.; Everard, Amandine; Meunier, Nicolas; Gurden, Hirac; Martin, Claire

    2017-01-01

    Leptin, the product of the Ob(Lep) gene, is a peptide hormone that plays a major role in maintaining the balance between food intake and energy expenditure. In the brain, leptin receptors are expressed by hypothalamic cells but also in the olfactory bulb, the first central structure coding for odors, suggesting a precise function of this hormone in odor-evoked activities. Although olfaction plays a key role in feeding behavior, the ability of the olfactory bulb to integrate the energy-related signal leptin is still missing. Therefore, we studied the fate of odor-induced activity in the olfactory bulb in the genetic context of leptin deficiency using the obese ob/ob mice. By means of an odor discrimination task with concomitant local field potential recordings, we showed that ob/ob mice perform better than wild-type (WT) mice in the early stage of the task. This behavioral gain of function was associated in parallel with profound changes in neuronal oscillations in the olfactory bulb. The distribution of the peaks in the gamma frequency range was shifted toward higher frequencies in ob/ob mice compared to WT mice before learning. More notably, beta oscillatory activity, which has been shown previously to be correlated with olfactory discrimination learning, was longer and stronger in expert ob/ob mice after learning. Since oscillations in the olfactory bulb emerge from mitral to granule cell interactions, our results suggest that cellular dynamics in the olfactory bulb are deeply modified in ob/ob mice in the context of olfactory learning.

  16. Mature and precursor brain-derived neurotrophic factor have individual roles in the mouse olfactory bulb.

    Directory of Open Access Journals (Sweden)

    Thomas Gerald Mast

    Full Text Available BACKGROUND: Sensory deprivation induces dramatic morphological and neurochemical changes in the olfactory bulb (OB that are largely restricted to glomerular and granule layer interneurons. Mitral cells, pyramidal-like neurons, are resistant to sensory-deprivation-induced changes and are associated with the precursor to brain-derived neurotrophic factor (proBDNF; here, we investigate its unknown function in the adult mouse OB. PRINCIPAL FINDINGS: As determined using brain-slice electrophysiology in a whole-cell configuration, brain-derived neurotrophic factor (BDNF, but not proBDNF, increased mitral cell excitability. BDNF increased mitral cell action potential firing frequency and decreased interspike interval in response to current injection. In a separate set of experiments, intranasal delivery of neurotrophic factors to awake, adult mice was performed to induce sustained interneuron neurochemical changes. ProBDNF, but not BDNF, increased activated-caspase 3 and reduced tyrosine hydroxylase immunoreactivity in OB glomerular interneurons. In a parallel set of experiments, short-term sensory deprivation produced by unilateral naris occlusion generated an identical phenotype. CONCLUSIONS: Our results indicate that only mature BDNF increases mitral cell excitability whereas proBDNF remains ineffective. Our demonstration that proBDNF activates an apoptotic marker in vivo is the first for any proneurotrophin and establishes a role for proBDNF in a model of neuronal plasticity.

  17. 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.

  18. Vasoactive intestinal polypeptide mediates circadian rhythms in mammalian olfactory bulb and olfaction.

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    Miller, Jae-Eun Kang; Granados-Fuentes, Daniel; Wang, Thomas; Marpegan, Luciano; Holy, Timothy E; Herzog, Erik D

    2014-04-23

    Accumulating evidence suggests that the olfactory bulbs (OBs) function as an independent circadian system regulating daily rhythms in olfactory performance. However, the cells and signals in the olfactory system that generate and coordinate these circadian rhythms are unknown. Using real-time imaging of gene expression, we found that the isolated olfactory epithelium and OB, but not the piriform cortex, express similar, sustained circadian rhythms in PERIOD2 (PER2). In vivo, PER2 expression in the OB of mice is circadian, approximately doubling with a peak around subjective dusk. Furthermore, mice exhibit circadian rhythms in odor detection performance with a peak at approximately subjective dusk. We also found that circadian rhythms in gene expression and odor detection performance require vasoactive intestinal polypeptide (VIP) or its receptor VPAC2R. VIP is expressed, in a circadian manner, in interneurons in the external plexiform and periglomerular layers, whereas VPAC2R is expressed in mitral and external tufted cells in the OB. Together, these results indicate that VIP signaling modulates the output from the OB to maintain circadian rhythms in the mammalian olfactory system.

  19. Direction of Head Trauma and its Effect on Olfactory Bulb Volume in Post-Traumatic Anosmia

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    S Farshchi

    2012-09-01

    Full Text Available Background: Anosmia is a physical sign in post-traumatic patients, which significantly reduces the quality of life. Anosmia occurs in up to 30% of cases with head trauma. In this study we aimed to compare the Olfactory Bulb Volume (OBV in patients with posttraumatic anosmia in different impact positions and also with healthy individuals to find the relation between the two variables. Methods: Thirty-eight patients with posttraumatic anosmia and 27 healthy individuals with normal olfactory function were recruited in this case-control study performed in Amir Alam Hospital in Tehran, Iran. Variables of age, sex, time of trauma, site of trauma (frontoparietal/occipital, side of trauma, OBV, the results of olfactory identification tests and olfactory threshold were extracted and evaluated. We used non-contrasted 1.5-Tesla coronal brain MRI for the measurement of OBV.Results: There were no significant differences between cases and controls regarding sex and age. Olfactory bulb volume was significantly smaller in cases compared to the controls (P=0.004. Among the case group, OBV was smaller in anterior versus posterior head traumas (P=0.02. OBV was also smaller in ipsilateral rather than the contralateral side of trauma (P=0.01.Conclusion: The direction of trauma had a significant effect on OBV and it was smaller in traumas to the anterior and also ipsilateral sides of the head. It seems that changes in OBV differ due to the direction of head trauma and it can be helpful in predicting the prognosis of posttraumatic anosmia. Further studies are required for more conclusive statements.

  20. Intrinsic conductances actively shape excitatory and inhibitory postsynaptic responses in olfactory bulb external tufted cells.

    Science.gov (United States)

    Liu, Shaolin; Shipley, Michael T

    2008-10-08

    The initial synapse in the olfactory system is from olfactory nerve (ON) terminals to postsynaptic targets in olfactory bulb glomeruli. Recent studies have disclosed multiple presynaptic factors that regulate this important linkage, but less is known about the contribution of postsynaptic intrinsic conductances to integration at these synapses. The present study demonstrates voltage-dependent amplification of EPSPs in external tufted (ET) cells in response to monosynaptic (ON) inputs. This amplification is mainly exerted by persistent Na(+) conductance. Larger EPSPs, which bring the membrane potential to a relatively depolarized level, are further boosted by the low-voltage-activated Ca(2+) conductance. In contrast, the hyperpolarization-activated nonselective cation conductance (I(h)) attenuates EPSPs mainly by reducing EPSP duration; this also reduces temporal summation of multiple EPSPs. Regulation of EPSPs by these subthreshold, voltage-dependent conductances can enhance both the signal-to-noise ratio and the temporal summation of multiple synaptic inputs and thus help ET cells differentiate high- and low-frequency synaptic inputs. I(h) can also transform inhibitory inputs to postsynaptic excitation. When the ET cell membrane potential is relatively depolarized, as during a burst of action potentials, IPSPs produce classic inhibition. However, near resting membrane potentials where I(h) is engaged, IPSPs produce rebound bursts of action potentials. ET cells excite GABAergic PG cells. Thus, the transformation of inhibitory inputs to postsynaptic excitation in ET cells may enhance intraglomerular inhibition of mitral/tufted cells, the main output neurons in the olfactory bulb, and hence shape signaling to olfactory cortex.

  1. 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.

  2. Protein expression differs between neural progenitor cells from the adult rat brain subventricular zone and olfactory bulb

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    Bürgers Heinrich F

    2008-01-01

    Full Text Available Abstract Background Neural progenitor cells can be isolated from various regions of the adult mammalian brain, including the forebrain structures of the subventricular zone and the olfactory bulb. Currently it is unknown whether functional differences in these progenitor cell populations can already be found on the molecular level. Therefore, we compared protein expression profiles between progenitor cells isolated from the subventricular zone and the olfactory bulb using a proteomic approach based on two-dimensional gel electrophoresis and mass spectrometry. The subventricular zone and the olfactory bulb are connected by the Rostral Migratory Stream (RMS, in which glial fibrillary acidic protein (GFAP-positive cells guide neuroblasts. Recent literature suggested that these GFAP-positive cells possess neurogenic potential themselves. In the current study, we therefore compared the cultured neurospheres for the fraction of GFAP-positive cells and their morphology of over a prolonged period of time. Results We found significant differences in the protein expression patterns between subventricular zone and olfactory bulb neural progenitor cells. Of the differentially expressed protein spots, 105 were exclusively expressed in the subventricular zone, 23 showed a lower expression and 51 a higher expression in the olfactory bulb. The proteomic data showed that more proteins are differentially expressed in olfactory bulb progenitors with regard to proteins involved in differentiation and microenvironmental integration, as compared to the subventricular zone progenitors. Compared to 94% of all progenitors of the subventricular zone expressed GFAP, nearly none in the olfactory bulb cultures expressed GFAP. Both GFAP-positive subpopulations differed also in morphology, with the olfactory bulb cells showing more branching. No differences in growth characteristics such as doubling time, and passage lengths could be found over 26 consecutive passages in the

  3. 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.

  4. 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.

  5. Coding Odorant Concentration through Activation Timing between the Medial and Lateral Olfactory Bulb

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    Zhishang Zhou

    2012-11-01

    Full Text Available In mammals, each olfactory bulb (OB contains a pair of mirror-symmetric glomerular maps organized to reflect odorant receptor identity. The functional implication of maintaining these symmetric medial-lateral maps within each OB remains unclear. Here, using in vivo multielectrode recordings to simultaneously detect odorant-induced activity across the entire OB, we reveal a timing difference in the odorant-evoked onset latencies between the medial and lateral halves. Interestingly, the latencies in the medial and lateral OB decreased at different rates as odorant concentration increased, causing the timing difference between them to also diminish. As a result, output neurons in the medial and lateral OB fired with greater synchrony at higher odorant concentrations. Thus, we propose that temporal differences in activity between the medial and lateral OB can dynamically code odorant concentration, which is subsequently decoded in the olfactory cortex through the integration of synchronous action potentials.

  6. Olfactory Bulb Deep Short-Axon Cells Mediate Widespread Inhibition of Tufted Cell Apical Dendrites.

    Science.gov (United States)

    Burton, Shawn D; LaRocca, Greg; Liu, Annie; Cheetham, Claire E J; Urban, Nathaniel N

    2017-02-01

    In the main olfactory bulb (MOB), the first station of sensory processing in the olfactory system, GABAergic interneuron signaling shapes principal neuron activity to regulate olfaction. However, a lack of known selective markers for MOB interneurons has strongly impeded cell-type-selective investigation of interneuron function. Here, we identify the first selective marker of glomerular layer-projecting deep short-axon cells (GL-dSACs) and investigate systematically the structure, abundance, intrinsic physiology, feedforward sensory input, neuromodulation, synaptic output, and functional role of GL-dSACs in the mouse MOB circuit. GL-dSACs are located in the internal plexiform layer, where they integrate centrifugal cholinergic input with highly convergent feedforward sensory input. GL-dSAC axons arborize extensively across the glomerular layer to provide highly divergent yet selective output onto interneurons and principal tufted cells. GL-dSACs are thus capable of shifting the balance of principal tufted versus mitral cell activity across large expanses of the MOB in response to diverse sensory and top-down neuromodulatory input. The identification of cell-type-selective molecular markers has fostered tremendous insight into how distinct interneurons shape sensory processing and behavior. In the main olfactory bulb (MOB), inhibitory circuits regulate the activity of principal cells precisely to drive olfactory-guided behavior. However, selective markers for MOB interneurons remain largely unknown, limiting mechanistic understanding of olfaction. Here, we identify the first selective marker of a novel population of deep short-axon cell interneurons with superficial axonal projections to the sensory input layer of the MOB. Using this marker, together with immunohistochemistry, acute slice electrophysiology, and optogenetic circuit mapping, we reveal that this novel interneuron population integrates centrifugal cholinergic input with broadly tuned feedforward sensory

  7. 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.

  8. The neuroanatomical organization of projection neurons associated with different olfactory bulb pathways in the sea lamprey, Petromyzon marinus.

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    Warren W Green

    Full Text Available Although there is abundant evidence for segregated processing in the olfactory system across vertebrate taxa, the spatial relationship between the second order projection neurons (PNs of olfactory subsystems connecting sensory input to higher brain structures is less clear. In the sea lamprey, there is tight coupling between olfaction and locomotion via PNs extending to the posterior tuberculum from the medial region of the olfactory bulb. This medial region receives peripheral input predominantly from the accessory olfactory organ. However, the axons from olfactory sensory neurons residing in the main olfactory epithelium extend to non-medial regions of the olfactory bulb, and the non-medial bulbar PNs extend their axons to the lateral pallium. It is not known if the receptive fields of the PNs in the two output pathways overlap; nor has the morphology of these PNs been investigated. In this study, retrograde labelling was utilized to investigate the PNs belonging to medial and non-medial projections. The dendrites and somata of the medial PNs were confined to medial glomerular neuropil, and dendrites of non-medial PNs did not enter this territory. The cell bodies and dendrites of the non-medial PNs were predominantly located below the glomeruli (frequently deeper in the olfactory bulb. While PNs in both locations contained single or multiple primary dendrites, the somal size was greater for medial than for non-medial PNs. When considered with the evidence-to-date, this study shows different neuroanatomical organization for medial olfactory bulb PNs extending to locomotor control centers and non-medial PNs extending to the lateral pallium in this vertebrate.

  9. The neuroanatomical organization of projection neurons associated with different olfactory bulb pathways in the sea lamprey, Petromyzon marinus.

    Science.gov (United States)

    Green, Warren W; Basilious, Alfred; Dubuc, Réjean; Zielinski, Barbara S

    2013-01-01

    Although there is abundant evidence for segregated processing in the olfactory system across vertebrate taxa, the spatial relationship between the second order projection neurons (PNs) of olfactory subsystems connecting sensory input to higher brain structures is less clear. In the sea lamprey, there is tight coupling between olfaction and locomotion via PNs extending to the posterior tuberculum from the medial region of the olfactory bulb. This medial region receives peripheral input predominantly from the accessory olfactory organ. However, the axons from olfactory sensory neurons residing in the main olfactory epithelium extend to non-medial regions of the olfactory bulb, and the non-medial bulbar PNs extend their axons to the lateral pallium. It is not known if the receptive fields of the PNs in the two output pathways overlap; nor has the morphology of these PNs been investigated. In this study, retrograde labelling was utilized to investigate the PNs belonging to medial and non-medial projections. The dendrites and somata of the medial PNs were confined to medial glomerular neuropil, and dendrites of non-medial PNs did not enter this territory. The cell bodies and dendrites of the non-medial PNs were predominantly located below the glomeruli (frequently deeper in the olfactory bulb). While PNs in both locations contained single or multiple primary dendrites, the somal size was greater for medial than for non-medial PNs. When considered with the evidence-to-date, this study shows different neuroanatomical organization for medial olfactory bulb PNs extending to locomotor control centers and non-medial PNs extending to the lateral pallium in this vertebrate.

  10. 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.

  11. Dissecting local circuits: parvalbumin interneurons underlie broad feedback control of olfactory bulb output.

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    Miyamichi, Kazunari; Shlomai-Fuchs, Yael; Shu, Marvin; Weissbourd, Brandon C; Luo, Liqun; Mizrahi, Adi

    2013-12-04

    In the mouse olfactory bulb, information from sensory neurons is extensively processed by local interneurons before being transmitted to the olfactory cortex by mitral and tufted (M/T) cells. The precise function of these local networks remains elusive because of the vast heterogeneity of interneurons, their diverse physiological properties, and their complex synaptic connectivity. Here we identified the parvalbumin interneurons (PVNs) as a prominent component of the M/T presynaptic landscape by using an improved rabies-based transsynaptic tracing method for local circuits. In vivo two-photon-targeted patch recording revealed that PVNs have exceptionally broad olfactory receptive fields and exhibit largely excitatory and persistent odor responses. Transsynaptic tracing indicated that PVNs receive direct input from widely distributed M/T cells. Both the anatomical and functional extent of this M/T→PVN→M/T circuit contrasts with the narrowly confined M/T→granule cell→M/T circuit, suggesting that olfactory information is processed by multiple local circuits operating at distinct spatial scales.

  12. BDNF promoter-mediated beta-galactosidase expression in the olfactory epithelium and bulb.

    Science.gov (United States)

    Clevenger, Amy C; Salcedo, Ernesto; Jones, Kevin R; Restrepo, Diego

    2008-07-01

    The neurotrophin brain-derived neurotrophic factor (BDNF) has been implicated in the generation and differentiation of new olfactory sensory neurons (OSNs) and in the regulation of branching of OSN axons in their target glomeruli. However, previous reports of BDNF mRNA and protein expression in olfactory epithelium and olfactory bulb (OB) have been inconsistent, raising questions on the proposed roles for BDNF. Here, we report on beta-galactosidase (beta-gal) expression in adult gene-targeted mice where the BDNF promoter drives expression of the Escherichia coli lacZ gene (BDNF(lacZneo) mice). We find that beta-gal is expressed in a small subset of OSNs with axons that reach the olfactory nerve layers throughout the OB. In the OB, we find expression of beta-gal in gamma-aminobutyric acidergic but not dopaminergic periglomerular cells and external tufted cells and in interneurons located in the mitral cell layer. Our results are inconsistent with the regulation of generation and differentiation of new OSNs elicited by the release of BDNF from horizontal basal cells. The results are consistent with a role for BDNF in competitive branching of OSN axons within the glomeruli of the OB.

  13. Dissecting Local Circuits: Parvalbumin Interneurons Underlie Broad Feedback Control of Olfactory Bulb Output

    Science.gov (United States)

    Miyamichi, Kazunari; Shlomai-Fuchs, Yael; Shu, Marvin; Weissbourd, Brandon C.

    2014-01-01

    Summary In the mouse olfactory bulb, information from sensory neurons is extensively processed by local interneurons before being transmitted to the olfactory cortex by mitral and tufted (M/T) cells. The precise function of these local networks remains elusive because of the vast heterogeneity of interneurons, their diverse physiological properties, and their complex synaptic connectivity. Here we identified the parvalbumin interneurons (PVNs) as a prominent component of the M/T presynaptic landscape by using an improved rabies-based trans-synaptic tracing method for local circuits. In vivo two-photon targeted patch recording revealed that PVNs have exceptionally broad olfactory receptive fields, and exhibit largely excitatory and persistent odor responses. Trans-synaptic tracing indicated that PVNs receive direct input from widely distributed M/T cells. Both the anatomical and functional extent of this M/T→PVN→M/T circuit contrasts with the narrowly confined M/T→granule cell→M/T circuit, suggesting that olfactory information is processed by multiple local circuits operating at distinct spatial scales. PMID:24239125

  14. The olfactory bulb in newborn piglet is a reservoir of neural stem and progenitor cells.

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    Lee J Martin

    Full Text Available The olfactory bulb (OB periventricular zone is an extension of the forebrain subventricular zone (SVZ and thus is a source of neuroprogenitor cells and neural stem cells. While considerable information is available on the SVZ-OB neural stem cell (NSC/neuroprogenitor cell (NPC niche in rodents, less work has been done on this system in large animals. The newborn piglet is used as a preclinical translational model of neonatal hypoxic-ischemic brain damage, but information about the endogenous sources of NSCs/NPCs in piglet is needed to implement endogenous or autologous cell-based therapies in this model. We characterized NSC/NPC niches in piglet forebrain and OB-SVZ using western blotting, histological, and cell culture methods. Immunoblotting revealed nestin, a NSC/NPC marker, in forebrain-SVZ and OB-SVZ in newborn piglet. Several progenitor or newborn neuron markers, including Dlx2, musashi, doublecortin, and polysialated neural cell adhesion molecule were also detected in OB-SVZ by immunoblotting. Immunohistochemistry confirmed the presence of nestin, musashi, and doublecortin in forebrain-SVZ and OB-SVZ. Bromodeoxyuridine (BrdU labeling showed that the forebrain-SVZ and OB-SVZ accumulate newly replicated cells. BrdU-positive cells were immunolabeled for astroglial, oligodendroglial, and neuronal markers. A lateral migratory pathway for newly born neuron migration to primary olfactory cortex was revealed by BrdU labeling and co-labeling for doublecortin and class III β tubulin. Isolated and cultured forebrain-SVZ and OB-SVZ cells from newborn piglet had the capacity to generate numerous neurospheres. Single cell clonal analysis of neurospheres revealed the capacity for self-renewal and multipotency. Neurosphere-derived cells differentiated into neurons, astrocytes, and oligodendrocytes and were amenable to permanent genetic tagging with lentivirus encoding green fluorescent protein. We conclude that the piglet OB-SVZ is a reservoir of NSCs

  15. The olfactory bulb in newborn piglet is a reservoir of neural stem and progenitor cells.

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    Martin, Lee J; Katzenelson, Alyssa; Koehler, Raymond C; Chang, Qing

    2013-01-01

    The olfactory bulb (OB) periventricular zone is an extension of the forebrain subventricular zone (SVZ) and thus is a source of neuroprogenitor cells and neural stem cells. While considerable information is available on the SVZ-OB neural stem cell (NSC)/neuroprogenitor cell (NPC) niche in rodents, less work has been done on this system in large animals. The newborn piglet is used as a preclinical translational model of neonatal hypoxic-ischemic brain damage, but information about the endogenous sources of NSCs/NPCs in piglet is needed to implement endogenous or autologous cell-based therapies in this model. We characterized NSC/NPC niches in piglet forebrain and OB-SVZ using western blotting, histological, and cell culture methods. Immunoblotting revealed nestin, a NSC/NPC marker, in forebrain-SVZ and OB-SVZ in newborn piglet. Several progenitor or newborn neuron markers, including Dlx2, musashi, doublecortin, and polysialated neural cell adhesion molecule were also detected in OB-SVZ by immunoblotting. Immunohistochemistry confirmed the presence of nestin, musashi, and doublecortin in forebrain-SVZ and OB-SVZ. Bromodeoxyuridine (BrdU) labeling showed that the forebrain-SVZ and OB-SVZ accumulate newly replicated cells. BrdU-positive cells were immunolabeled for astroglial, oligodendroglial, and neuronal markers. A lateral migratory pathway for newly born neuron migration to primary olfactory cortex was revealed by BrdU labeling and co-labeling for doublecortin and class III β tubulin. Isolated and cultured forebrain-SVZ and OB-SVZ cells from newborn piglet had the capacity to generate numerous neurospheres. Single cell clonal analysis of neurospheres revealed the capacity for self-renewal and multipotency. Neurosphere-derived cells differentiated into neurons, astrocytes, and oligodendrocytes and were amenable to permanent genetic tagging with lentivirus encoding green fluorescent protein. We conclude that the piglet OB-SVZ is a reservoir of NSCs and NPCs suitable

  16. Specific entrainment of mitral cells during gamma oscillation in the rat olfactory bulb.

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    David, François O; Hugues, Etienne; Cenier, Tristan; Fourcaud-Trocmé, Nicolas; Buonviso, Nathalie

    2009-10-01

    Local field potential (LFP) oscillations are often accompanied by synchronization of activity within a widespread cerebral area. Thus, the LFP and neuronal coherence appear to be the result of a common mechanism that underlies neuronal assembly formation. We used the olfactory bulb as a model to investigate: (1) the extent to which unitary dynamics and LFP oscillations can be correlated and (2) the precision with which a model of the hypothesized underlying mechanisms can accurately explain the experimental data. For this purpose, we analyzed simultaneous recordings of mitral cell (MC) activity and LFPs in anesthetized and freely breathing rats in response to odorant stimulation. Spike trains were found to be phase-locked to the gamma oscillation at specific firing rates and to form odor-specific temporal patterns. The use of a conductance-based MC model driven by an approximately balanced excitatory-inhibitory input conductance and a relatively small inhibitory conductance that oscillated at the gamma frequency allowed us to provide one explanation of the experimental data via a mode-locking mechanism. This work sheds light on the way network and intrinsic MC properties participate in the locking of MCs to the gamma oscillation in a realistic physiological context and may result in a particular time-locked assembly. Finally, we discuss how a self-synchronization process with such entrainment properties can explain, under experimental conditions: (1) why the gamma bursts emerge transiently with a maximal amplitude position relative to the stimulus time course; (2) why the oscillations are prominent at a specific gamma frequency; and (3) why the oscillation amplitude depends on specific stimulus properties. We also discuss information processing and functional consequences derived from this mechanism.

  17. Spontaneous firing in olfactory bulb neurons of Bufo bufo gargarizans in and after hibernation

    Institute of Scientific and Technical Information of China (English)

    Chuancheng Liang; Shaokang Bian; Xia Peng; Liwen Wang

    2011-01-01

    Microelectrode technique was used to record the spontaneous electrical activities of the neurons in olfactory bulb of the Bufo bufo gargarizans, both in hibernation and after hibernation. This study investigated the electrophysiological characteristics of amphibian olfactory bulb in the period of hibernation and after hibernation and its effects on the start of hibernation and spontaneous awakening. The research showed four forms of spontaneous firings: single spontaneous firing, burst spontaneous firing, irregular spontaneous firing and consecutive single spontaneous firing. The single spontaneous firing includes slow depolarized spontaneous firing and fast depolarized spontaneous firing, and the slow depolarized spontaneous firing occurs only during the hibernation period. In hibernation, the low amplitude and low frequency firing with a longer duration may be relevant to maintaining the tonicity of the central nervous system in toads that are in hibernation, and this kind of firing may also provide an excited basis for their arousal from hibernation. After hibernation, the amplitude and frequency of firing increase, but the firing duration gets shorter. This form of short-term firing, which may be a phenomenon of sensory neurons fast adapting, is one of the neuronal mechanisms for the arousal of hibernating animals.

  18. A transient, RCK4-like K+ current in cultured Xenopus olfactory bulb neurons.

    Science.gov (United States)

    Engel, J; Rabba, J; Schild, D

    1996-09-01

    A transient K+ current in cultured olfactory bulb neurons of Xenopus tadpoles was studied using the whole-cell patch-clamp technique. The current, which was resistant to 80 mM tetraethylammoniumchloride (TEA) and 10 nM charybdotoxin but blocked by 5 mM 4-aminopyridine (4-AP), activated between -60 and -40 mV and showed time- and voltage-dependent inactivation. Its peak amplitude was nearly independent of the extracellular K+ concentration ([K+]o) in the range of 0.05 to 10 mM, indicating that its conductance increased upon increasing [K+]o. The transient K+ current showed a slow recovery from inactivation with the time for half-maximum recovery from a conditioning pulse to 80 mV for 1 s varying from 100 ms to 500 ms. Complete recovery required as much as 5-10 s at -80 mV, but could be speeded up at hyperpolarized potentials. The current resembles the RCK4 (Kv1.4) current of rat neurons except that its recovery from inactivation was independent of [K+]o. High-frequency stimulation (20-67 Hz) of the neurons with short (5 ms) voltage pulses resulted in a frequency-dependent, progressive inactivation of the transient K+ current. This suggests that, during phasic responses of olfactory bulb neurons, inactivation of the transient K+ current occurs and may lead to lengthening of action potentials and facilitation of synaptic transmission.

  19. Impact of actin filament stabilization on adult hippocampal and olfactory bulb neurogenesis.

    Science.gov (United States)

    Kronenberg, Golo; Gertz, Karen; Baldinger, Tina; Kirste, Imke; Eckart, Sarah; Yildirim, Ferah; Ji, Shengbo; Heuser, Isabella; Schröck, Helmut; Hörtnagl, Heide; Sohr, Reinhard; Djoufack, Pierre Chryso; Jüttner, René; Glass, Rainer; Przesdzing, Ingo; Kumar, Jitender; Freyer, Dorette; Hellweg, Rainer; Kettenmann, Helmut; Fink, Klaus Benno; Endres, Matthias

    2010-03-03

    Rearrangement of the actin cytoskeleton is essential for dynamic cellular processes. Decreased actin turnover and rigidity of cytoskeletal structures have been associated with aging and cell death. Gelsolin is a Ca(2+)-activated actin-severing protein that is widely expressed throughout the adult mammalian brain. Here, we used gelsolin-deficient (Gsn(-/-)) mice as a model system for actin filament stabilization. In Gsn(-/-) mice, emigration of newly generated cells from the subventricular zone into the olfactory bulb was slowed. In vitro, gelsolin deficiency did not affect proliferation or neuronal differentiation of adult neural progenitors cells (NPCs) but resulted in retarded migration. Surprisingly, hippocampal neurogenesis was robustly induced by gelsolin deficiency. The ability of NPCs to intrinsically sense excitatory activity and thereby implement coupling between network activity and neurogenesis has recently been established. Depolarization-induced [Ca(2+)](i) increases and exocytotic neurotransmitter release were enhanced in Gsn(-/-) synaptosomes. Importantly, treatment of Gsn(-/-) synaptosomes with mycotoxin cytochalasin D, which, like gelsolin, produces actin disassembly, decreased enhanced Ca(2+) influx and subsequent exocytotic norepinephrine release to wild-type levels. Similarly, depolarization-induced glutamate release from Gsn(-/-) brain slices was increased. Furthermore, increased hippocampal neurogenesis in Gsn(-/-) mice was associated with a special microenvironment characterized by enhanced density of perfused vessels, increased regional cerebral blood flow, and increased endothelial nitric oxide synthase (NOS-III) expression in hippocampus. Together, reduced filamentous actin turnover in presynaptic terminals causes increased Ca(2+) influx and, subsequently, elevated exocytotic neurotransmitter release acting on neural progenitors. Increased neurogenesis in Gsn(-/-) hippocampus is associated with a special vascular niche for neurogenesis.

  20. 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.

  1. Odour perception following bilateral damage to the olfactory bulbs: a possible case of blind smell.

    Science.gov (United States)

    Zucco, Gesualdo M; Prior, Massimo; Sartori, Giuseppe; Stevenson, Richard J

    2013-02-01

    Unconsciously detected chemicals may affect human behaviour (Kirk-Smith et al., 1983; Stern and McClintock, 1998; Zucco et al., 2009), likeability judgements (Li et al., 2007) and brain activity (Lorig et al., 1990; Sobel et al., 1999). No studies, however, have investigated blind smell - the hypothetical olfactory counterpart of blindsight (Weiskrantz et al., 1974). In this report, free and cued olfactory identification of suprathreshold odorants varying in irritancy (i.e., low or no irritant odours versus irritant odours), and taste identification abilities, were examined in patient MB who had undergone surgery for a meningioma. Post-operative imaging revealed encephalomalacia in the left gyrus rectus, with ablation of the left olfactory bulb and damage to the right, subcortical abnormality on the left near the orbital cortex, and damage to a small section of the right gyrus rectus. On free identification MB, while denying a capacity to smell the odours, still correctly identified some and detected others significantly above chance. In contrast, awareness always accompanied correct detections of irritant odours. Cued odour identification was at chance and no taste impairments were observed. We suggest, tentatively, that MB's unusual pattern of awareness when detecting and identifying odours relative to irritant odours may represent an example of 'blind smell'. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. Expression of transient receptor potential (TRP) channel mRNAs in the mouse olfactory bulb.

    Science.gov (United States)

    Dong, Hong-Wei; Davis, James C; Ding, ShengYuan; Nai, Qiang; Zhou, Fu-Ming; Ennis, Matthew

    2012-08-22

    Transient receptor potential (TRP) channels are a large family of cation channels. The 28 TRP channel subtypes in rodent are divided into 6 subfamilies: TRPC1-7, TRPV1-6, TRPM1-8, TRPP2/3/5, TRPML1-3 and TRPA1. TRP channels are involved in peripheral olfactory transduction. Several TRPC channels are expressed in unidentified neurons in the main olfactory bulb (OB), but the expression of most TRP channels in the OB has not been investigated. The present study employed RT-PCR as an initial survey of the expression of TRP channel mRNAs in the mouse OB and in 3 cell types: external tufted, mitral and granule cells. All TRP channel mRNAs except TRPV5 were detected in OB tissue. Single cell RT-PCR revealed that external tufted, mitral and granule cell populations expressed in aggregate 14 TRP channel mRNAs encompassing members of all 6 subfamilies. These different OB neuron populations expressed 7-12 channel mRNAs. Common channel expression was more similar among external tufted and mitral cells than among these cells and granule cells. These results indicate that a large number of TRP channel subtypes are expressed in OB neurons, providing the molecular bases for these channels to regulate OB neuron activity and central olfactory processing.

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

    Directory of Open Access Journals (Sweden)

    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.

  4. Greater addition of neurons to the olfactory bulb than to the cerebral cortex of eulipotyphlans but not rodents, afrotherians or primates

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    Pedro Furtado De Mattos Ribeiro

    2014-04-01

    Full Text Available The olfactory bulb is an evolutionarily old structure that antedates the appearance of a six-layered mammalian cerebral cortex. As such, the neuronal scaling rules that apply to scaling the mass of the olfactory bulb as a function of its number of neurons might be shared across mammalian groups, as we have found to be the case for the ensemble of non-cortical, non-cerebellar brain structures. Alternatively, the neuronal scaling rules that apply to the olfactory bulb might be distinct in those mammals that rely heavily on olfaction. The group previously referred to as Insectivora includes small mammals, some of which are now placed in Afrotheria, a base group in mammalian radiation, and others in Eulipotyphla, a group derived later, at the base of Laurasitheria. Here we show that the neuronal scaling rules that apply to building the olfactory bulb differ across eulipotyphlans and other mammals such that eulipotyphlans have more neurons concentrated in an olfactory bulb of similar size than afrotherians, glires and primates. Most strikingly, while the cerebral cortex gains neurons at a faster pace than the olfactory bulb in glires, and afrotherians follow this trend, it is the olfactory bulb that gains neurons at a faster pace than the cerebral cortex in eulipotyphlans, which contradicts the common view that the cerebral cortex is the fastest expanding structure in brain evolution. Our findings emphasize the importance of not using brain structure size as a proxy for numbers of neurons across mammalian orders, and are consistent with the notion that different selective pressures have acted upon the olfactory system of eulipotyphlans, glires and primates, with eulipotyphlans relying more on olfaction for their behavior than glires and primates. Surprisingly, however, the neuronal scaling rules for primates predict that the human olfactory bulb has as many neurons as the larger eulipotyphlan olfactory bulbs, which questions the classification of

  5. Effects of total saponins of Panax notoginseng on immature neuroblasts in the adult olfactory bulb following global cerebral ischemia/reperfusion

    Institute of Scientific and Technical Information of China (English)

    Xu He; Feng-jun Deng; Jin-wen Ge; Xiao-xin Yan; Ai-hua Pan; Zhi-yuan Li

    2015-01-01

    The main active components extracted from Panax notoginseng are total saponins. They have been shown to inhibit platelet aggregation, increase cerebral blood lfow, improve neurological behavior, decrease infarct volume and promote proliferation and differentiation of neural stem cells in the hippocampus and lateral ventricles. However, there is a lack of studies on whether total saponins of Panax notoginseng have potential benefits on immature neuroblasts in the olfactory bulb following ischemia and reperfusion. This study established a rat model of global cerebral ischemia and reperfusion using four-vessel occlusion. Rats were administered total sa-ponins of Panax notoginseng at 75 mg/kg intraperitoneally 30 minutes after ischemia then once a day, for either 7 or 14 days. Total saponins of Panax notoginseng enhanced the number of dou-blecortin (DCX)+ neural progenitor cells and increased co-localization of DCX with neuronal nuclei and phosphorylated cAMP response element-binding/DCX+ neural progenitor cells in the olfactory bulb at 7 and 14 days post ischemia. These ifndings indicate that following global brain ischemia/reperfusion, total saponins of Panax notoginseng promote differentiation of DCX+ cells expressing immature neuroblasts in the olfactory bulb and the underlying mechanism is related to the activation of the signaling pathway of cyclic adenosine monophosphate response element binding protein.

  6. Effects of total saponins of Panax notoginseng on immature neuroblasts in the adult olfactory bulb following global cerebral ischemia/reperfusion

    Directory of Open Access Journals (Sweden)

    Xu He

    2015-01-01

    Full Text Available The main active components extracted from Panax notoginseng are total saponins. They have been shown to inhibit platelet aggregation, increase cerebral blood flow, improve neurological behavior, decrease infarct volume and promote proliferation and differentiation of neural stem cells in the hippocampus and lateral ventricles. However, there is a lack of studies on whether total saponins of Panax notoginseng have potential benefits on immature neuroblasts in the olfactory bulb following ischemia and reperfusion. This study established a rat model of global cerebral ischemia and reperfusion using four-vessel occlusion. Rats were administered total saponins of Panax notoginseng at 75 mg/kg intraperitoneally 30 minutes after ischemia then once a day, for either 7 or 14 days. Total saponins of Panax notoginseng enhanced the number of doublecortin (DCX + neural progenitor cells and increased co-localization of DCX with neuronal nuclei and phosphorylated cAMP response element-binding/DCX + neural progenitor cells in the olfactory bulb at 7 and 14 days post ischemia. These findings indicate that following global brain ischemia/reperfusion, total saponins of Panax notoginseng promote differentiation of DCX + cells expressing immature neuroblasts in the olfactory bulb and the underlying mechanism is related to the activation of the signaling pathway of cyclic adenosine monophosphate response element binding protein.

  7. 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.

  8. Functional recovery of odor representations in regenerated sensory inputs to the olfactory bulb

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    Man C Cheung

    2014-01-01

    Full Text Available The olfactory system has a unique capacity for recovery from peripheral damage. After injury to the olfactory epithelium, olfactory sensory neurons (OSNs regenerate and re-converge on target glomeruli of the olfactory bulb (OB. Thus far, this process has been described anatomically for only a few defined populations of OSNs. Here we characterize this regeneration at a functional level by assessing how odor representations carried by OSN inputs to the OB recover after massive loss and regeneration of the sensory neuron population. We used chronic imaging of mice expressing synaptopHluorin in OSNs to monitor odor representations in the dorsal OB before lesion by the olfactotoxin methyl bromide and after a 12 week recovery period. Methyl bromide eliminated functional inputs to the OB, and these inputs recovered to near-normal levels of response magnitude within 12 weeks. We also found that the functional topography of odor representations recovered after lesion, with odorants evoking OSN input to glomerular foci within the same functional domains as before lesion. At a finer spatial scale, however, we found evidence for mistargeting of regenerated OSN axons onto OB targets, with odorants evoking synaptopHluorin signals in small foci that did not conform to a typical glomerular structure but whose distribution was nonetheless odorant-specific. These results indicate that OSNs have a robust ability to reestablish functional inputs to the OB and that the mechanisms underlying the topography of bulbar reinnervation during development persist in the adult and allow primary sensory representations to be largely restored after massive sensory neuron loss.

  9. Glycyrrhizin ameliorates oxidative stress and inflammation in hippocampus and olfactory bulb in lithium/pilocarpine-induced status epilepticus in rats.

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    González-Reyes, Susana; Santillán-Cigales, Juan Jair; Jiménez-Osorio, Angélica Saraí; Pedraza-Chaverri, José; Guevara-Guzmán, Rosalinda

    2016-10-01

    Glycyrrhizin (GL) is a triterpene present in the roots and rhizomes of Glycyrrhiza glabra that has anti-inflammatory, hepatoprotective and neuroprotective effects. Recently, it was demonstrated that GL produced neuroprotective effects on the postischemic brain as well as on the kainic acid injury model in rats. In addition to this, GL also prevented excitotoxic effects on primary cultures. The aims of the present study were to evaluate GL scavenging properties and to investigate GL's effect on oxidative stress and inflammation in the lithium/pilocarpine-induced seizure model in two cerebral regions, hippocampus and olfactory bulb, at acute time intervals (3 or 24h) after status epilepticus (SE). Fluorometric methods showed that GL scavenged three reactive oxygen species: hydrogen peroxide, peroxyl radicals and superoxide anions. In contrast, GL was unable to scavenge peroxynitrite, hydroxyl radicals, singlet oxygen and 2,2-diphenil-1-picrylhydrazyl (DPPH) radicals suggesting that GL is a weak scavenger. Additionally, administration of GL (50mg/kg, i.p.) 30min before pilocarpine administration significantly suppressed oxidative stress. Moreover, malondialdehyde levels were diminished and glutathione levels were maintained at control values in both cerebral regions at 3 and 24 after SE. At 24h after SE, glutathione S-transferase and superoxide dismutase activity increased in the hippocampus, while both glutathione reductase and glutathione peroxidase activity were unchanged in the olfactory bulb at that time. In addition, GL suppressed the induction of the proinflammatory cytokines interleukin-1 beta (IL-1β) and tumor necrosis factor alpha (TNF-α) in both cerebral regions evaluated. These results suggest that GL confers protection against pilocarpine damage via antioxidant and anti-inflammatory effects.

  10. A divergent pattern of sensory axonal projections is rendered convergent by second-order neurons in the accessory olfactory bulb.

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    Del Punta, Karina; Puche, Adam; Adams, Niels C; Rodriguez, Ivan; Mombaerts, Peter

    2002-09-12

    The mammalian vomeronasal system is specialized in pheromone detection. The neural circuitry of the accessory olfactory bulb (AOB) provides an anatomical substrate for the coding of pheromone information. Here, we describe the axonal projection pattern of vomeronasal sensory neurons to the AOB and the dendritic connectivity pattern of second-order neurons. Genetically traced sensory neurons expressing a given gene of the V2R class of vomeronasal receptors project their axons to six to ten glomeruli distributed in globally conserved areas of the AOB, a theme similar to V1R-expressing neurons. Surprisingly, second-order neurons tend to project their dendrites to glomeruli innervated by axons of sensory neurons expressing the same V1R or the same V2R gene. Convergence of receptor type information in the olfactory bulb may represent a common design in olfactory systems.

  11. 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

    Granule cells excitability in the turtle olfactory bulb was analyzed using whole cell recordings in current- and voltage-clamp mode. Low-threshold spikes (LTSs) were evoked at potentials that are subthreshold for Na spikes in normal medium. The LTSs were evoked from rest, but hyperpolarization...... 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...

  12. Functional roles of distributed synaptic clusters in the mitral-granule cell network of the olfactory bulb

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    Michele Migliore

    2010-09-01

    Full Text Available Odors are encoded in spatio-temporal patterns within the olfactory bulb, but the mechanisms of odor recognition and discrimination are poorly understood. It is reasonable to postulate that the olfactory code is sculpted by lateral and feedforward inhibition mediated by granule cells onto the mitral cells. Recent viral tracing and physiological studies revealed patterns of distributed granule cell synaptic clusters that provided additional clues to the possible mechanisms at the network level. The emerging properties and functional roles of these patterns, however, are unknown. Here, using a realistic model of 5 mitral and 100 granule cells we show how their synaptic network can dynamically self-organize and interact through an activity-dependent dendrodendritic mechanism. The results suggest that the patterns of distributed mitral-granule cell connectivity may represent the most recent history of odor inputs, and may contribute to the basic processes underlying mixture perception and odor qualities. The model predicts how and why the dynamical interactions between the active mitral cells through the granule cell synaptic clusters can account for a variety of puzzling behavioral results on odor mixtures and on the emergence of synthetic or analytic perception.

  13. 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

  14. Spatio-temporal characteristics of inhibition mapped by optical stimulation in mouse olfactory bulb

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    Alexander eLehmann

    2016-03-01

    Full Text Available Mitral and tufted cells (MTCs of the mammalian olfactory bulb (OB are connected via dendrodendritic synapses with inhibitory interneurons in the external plexiform layer. The range, spatial layout and temporal properties of inhibitory interactions between MTCs mediated by inhibitory interneurons remain unclear. Therefore we tested for inhibitory interactions using an optogenetic approach. We optically stimulated MTCs expressing channelrhodopsin-2 in transgenic mice, while recording from individual MTCs in juxtacellular or whole-cell configuration in vivo. We used a spatial noise stimulus for mapping interactions between MTCs belonging to different glomeruli in the dorsal bulb. Analyzing firing responses of MTCs to the stimulus, we did not find robust lateral inhibitory effects that were spatially specific. However, analysis of sub-threshold changes in the membrane potential revealed evidence for inhibitory interactions between MTCs that belong to different glomerular units. These lateral inhibitory effects were short-lived and spatially specific. MTC response maps showed hyperpolarizing effects radially extending over more than 5 glomerular diameters. The inhibitory maps exhibited non-symmetrical yet distance-dependent characteristics.

  15. Diabetes Impairs Wnt3 Protein-induced Neurogenesis in Olfactory Bulbs via Glutamate Transporter 1 Inhibition.

    Science.gov (United States)

    Wakabayashi, Tamami; Hidaka, Ryo; Fujimaki, Shin; Asashima, Makoto; Kuwabara, Tomoko

    2016-07-15

    Diabetes is associated with impaired cognitive function. Streptozotocin (STZ)-induced diabetic rats exhibit a loss of neurogenesis and deficits in behavioral tasks involving spatial learning and memory; thus, impaired adult hippocampal neurogenesis may contribute to diabetes-associated cognitive deficits. Recent studies have demonstrated that adult neurogenesis generally occurs in the dentate gyrus of the hippocampus, the subventricular zone, and the olfactory bulbs (OB) and is defective in patients with diabetes. We hypothesized that OB neurogenesis and associated behaviors would be affected in diabetes. In this study, we show that inhibition of Wnt3-induced neurogenesis in the OB causes several behavioral deficits in STZ-induced diabetic rats, including impaired odor discrimination, cognitive dysfunction, and increased anxiety. Notably, the sodium- and chloride-dependent GABA transporters and excitatory amino acid transporters that localize to GABAergic and glutamatergic terminals decreased in the OB of diabetic rats. Moreover, GAT1 inhibitor administration also hindered Wnt3-induced neurogenesis in vitro Collectively, these data suggest that STZ-induced diabetes adversely affects OB neurogenesis via GABA and glutamate transporter systems, leading to functional impairments in olfactory performance.

  16. Profound context-dependent plasticity of mitral cell responses in olfactory bulb.

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    Wilder Doucette

    2008-10-01

    Full Text Available On the basis of its primary circuit it has been postulated that the olfactory bulb (OB is analogous to the retina in mammals. In retina, repeated exposure to the same visual stimulus results in a neural representation that remains relatively stable over time, even as the meaning of that stimulus to the animal changes. Stability of stimulus representation at early stages of processing allows for unbiased interpretation of incoming stimuli by higher order cortical centers. The alternative is that early stimulus representation is shaped by previously derived meaning, which could allow more efficient sampling of odor space providing a simplified yet biased interpretation of incoming stimuli. This study helps place the olfactory system on this continuum of subjective versus objective early sensory representation. Here we show that odor responses of the output cells of the OB, mitral cells, change transiently during a go-no-go odor discrimination task. The response changes occur in a manner that increases the ability of the circuit to convey information necessary to discriminate among closely related odors. Remarkably, a switch between which of the two odors is rewarded causes mitral cells to switch the polarity of their divergent responses. Taken together these results redefine the function of the OB as a transiently modifiable (active filter, shaping early odor representations in behaviorally meaningful ways.

  17. Diversity in olfactory bulb size in birds reflects allometry, ecology, and phylogeny.

    Science.gov (United States)

    Corfield, Jeremy R; Price, Kasandra; Iwaniuk, Andrew N; Gutierrez-Ibañez, Cristian; Birkhead, Tim; Wylie, Douglas R

    2015-01-01

    The relative size of olfactory bulbs (OBs) is correlated with olfactory capabilities across vertebrates and is widely used to assess the relative importance of olfaction to a species' ecology. In birds, variations in the relative size of OBs are correlated with some behaviors; however, the factors that have led to the high level of diversity seen in OB sizes across birds are still not well understood. In this study, we use the relative size of OBs as a neuroanatomical proxy for olfactory capabilities in 135 species of birds, representing 21 orders. We examine the scaling of OBs with brain size across avian orders, determine likely ancestral states and test for correlations between OB sizes and habitat, ecology, and behavior. The size of avian OBs varied with the size of the brain and this allometric relationship was for the most part isometric, although species did deviate from this trend. Large OBs were characteristic of more basal species and in more recently derived species the OBs were small. Living and foraging in a semi-aquatic environment was the strongest variable driving the evolution of large OBs in birds; olfaction may provide cues for navigation and foraging in this otherwise featureless environment. Some of the diversity in OB sizes was also undoubtedly due to differences in migratory behavior, foraging strategies and social structure. In summary, relative OB size in birds reflect allometry, phylogeny and behavior in ways that parallel that of other vertebrate classes. This provides comparative evidence that supports recent experimental studies into avian olfaction and suggests that olfaction is an important sensory modality for all avian species.

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

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    Fumiaki Imamura

    Full Text Available BACKGROUND: 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. PRINCIPAL FINDINGS: 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. SIGNIFICANCE: 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.

  19. Structural basis for cholinergic regulation of neural circuits in the mouse olfactory bulb.

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    Hamamoto, Masakazu; Kiyokage, Emi; Sohn, Jaerin; Hioki, Hiroyuki; Harada, Tamotsu; Toida, Kazunori

    2017-02-15

    Odor information is regulated by olfactory inputs, bulbar interneurons, and centrifugal inputs in the olfactory bulb (OB). Cholinergic neurons projecting from the nucleus of the horizontal limb of the diagonal band of Broca and the magnocellular preoptic nucleus are one of the primary centrifugal inputs to the OB. In this study, we focused on cholinergic regulation of the OB and analyzed neural morphology with a particular emphasis on the projection pathways of cholinergic neurons. Single-cell imaging of a specific neuron within dense fibers is critical to evaluate the structure and function of the neural circuits. We labeled cholinergic neurons by infection with virus vector and then reconstructed them three-dimensionally. We also examined the ultramicrostructure of synapses by electron microscopy tomography. To further clarify the function of cholinergic neurons, we performed confocal laser scanning microscopy to investigate whether other neurotransmitters are present within cholinergic axons in the OB. Our results showed the first visualization of complete cholinergic neurons, including axons projecting to the OB, and also revealed frequent axonal branching within the OB where it innervated multiple glomeruli in different areas. Furthermore, electron tomography demonstrated that cholinergic axons formed asymmetrical synapses with a morphological variety of thicknesses of the postsynaptic density. Although we have not yet detected the presence of other neurotransmitters, the range of synaptic morphology suggests multiple modes of transmission. The present study elucidates the ways that cholinergic neurons could contribute to the elaborate mechanisms involved in olfactory processing in the OB. J. Comp. Neurol. 525:574-591, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  20. Calretinin periglomerular interneurons in mice olfactory bulb: cells of few words

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    Alex Fogli Iseppe

    2016-10-01

    Full Text Available Within the olfactory bulb (OB, periglomerular (PG cells consist of various types of interneurons, generally classified by their chemical properties such as neurotransmitter and calcium binding proteins.Calretinin (CR characterizes morphologically and functionally the more numerous and one of the less known subpopulation of PG cells in the OB. Using of transgenic mice expressing eGFP under the CR promoter, we have tried to obtain the first functional characterization of these cells. Electrophysiological recordings were made in these cells using the patch-clamp technique in thin slices. Using ion substitution methods and specific blockers, we dissected the main voltage-dependent conductances present, obtaining a complete kinetic description for each of them.The more peculiar property of these cells from the electrophysiological point of view is the presence only of a single K-current, the IA - there is no trace of delayed rectifier or of Ca-dependent K-current. Other currents identified, isolated and fully characterised are two inward currents, a fast sodium current and a small L-type calcium current, and an inward rectifier, h-type cationic current. As a consequence of the peculiar complement of voltage-dependent conductances present in these cells, and in particular the absence of delayed-rectifier potassium currents, under the functional point of view these cells present two interesting properties.First, in response to prolonged depolarisations, after the inactivation of the A-current, these cells behave as a purely ohmic elements, showing no outward rectification. Second, the CR cells studied can respond only with a single action potential to excitatory inputs; since they send inhibitory synapses to projection neurones, they seem to be designed to inhibit responses of the main neurones to isolated, random excitatory signals, losing their vetoing effect for more structured, repetitive excitatory signals, as result from odour detection

  1. Experience-Dependent Plasticity in Accessory Olfactory Bulb Interneurons following Male-Male Social Interaction.

    Science.gov (United States)

    Cansler, Hillary L; Maksimova, Marina A; Meeks, Julian P

    2017-07-26

    Chemosensory information processing in the mouse accessory olfactory system guides the expression of social behavior. After salient chemosensory encounters, the accessory olfactory bulb (AOB) experiences changes in the balance of excitation and inhibition at reciprocal synapses between mitral cells (MCs) and local interneurons. The mechanisms underlying these changes remain controversial. Moreover, it remains unclear whether MC-interneuron plasticity is unique to specific behaviors, such as mating, or whether it is a more general feature of the AOB circuit. Here, we describe targeted electrophysiological studies of AOB inhibitory internal granule cells (IGCs), many of which upregulate the immediate-early gene Arc after male-male social experience. Following the resident-intruder paradigm, Arc-expressing IGCs in acute AOB slices from resident males displayed stronger excitation than nonexpressing neighbors when sensory inputs were stimulated. The increased excitability of Arc-expressing IGCs was not correlated with changes in the strength or number of excitatory synapses with MCs but was instead associated with increased intrinsic excitability and decreased HCN channel-mediated IH currents. Consistent with increased inhibition by IGCs, MCs responded to sensory input stimulation with decreased depolarization and spiking following resident-intruder encounters. These results reveal that nonmating behaviors drive AOB inhibitory plasticity and indicate that increased MC inhibition involves intrinsic excitability changes in Arc-expressing interneurons.SIGNIFICANCE STATEMENT The accessory olfactory bulb (AOB) is a site of experience-dependent plasticity between excitatory mitral cells (MCs) and inhibitory internal granule cells (IGCs), but the physiological mechanisms and behavioral conditions driving this plasticity remain unclear. Here, we report studies of AOB neuronal plasticity following male-male social chemosensory encounters. We show that the plasticity

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Duchamp, A.; Moyse, E.; Delaleu, J.-C.; Coronas, V.; Duchamp-Viret, P. [Laboratoire de Physiologie Neurosensorielle, Universite Claude Bernard and CNRS, F69622 Villeurbanne (France)

    1997-04-28

    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{sub 2} type in mammals. The present study assessed, in the frog, both the anatomical localization of D{sub 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 [{sup 125}I]iodosulpride-labelled D{sub 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{sub 2} antagonist eticlopride blocked the dopamine-induced reduction of mitral cell spontaneous activity.In the frog olfactory bulb, both anatomical localization of D{sub 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

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

    Institute of Scientific and Technical Information of China (English)

    Nai-An Xiao; Jing Zhang; Meng Zhou; Zhen Wei; Xi-Lin Wu; Xiao-Man Dai; Yuan-Gui Zhu

    2015-01-01

    Background:Early diagnosis assumes a vital role in an effective treatment of Alzheimer's disease (AD).Most of the current studies can only make anAD diagnosis after the manifestation of typical clinical symptoms.The present study aimed to investigate typical and other biomarkers of AD to find a possible early biomarker.Methods:A total of 14 5XFAD mice (at 3 and 6 months old),with 14 age-matched wild-type (WT) mice as control,were enrolled in this case-control study.Morris water maze test was performed to evaluate the cognitive function;buried food pellet test and olfactory maze test were employed to investigate the olfactory function;immunofluorescence to detect amyloid deposition and positron emission tomography to examine 2-deoxy-2-(18F) fluoro-D-glucose ([18F]-FDG) uptake in the hippocampus and cerebral cortex.Results:With the increasing age,cognitive performance (P =0.0262) and olfactory function were significantly deteriorated (day 1 P =0.0012,day 2 P =0.0031,day 3 P =0.0160,respectively) and the (18F)-FDG uptake was markedly decreased in multi-cerebral regions including the olfactory bulb (P < 0.0001),hippocampus (P =0.0121),and cerebral cortex (P < 0.0001).Of note,in 3-month-old 5XFAD mice,a significant decline of (18F)-FDG uptake in the olfactory bulb was found when compared with that of age-matched WT mice (P =0.023) while no significant difference was present when the uptakes in other cerebral regions were compared.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.

  5. A novel bioelectronic nose based on brain-machine interface using implanted electrode recording in vivo in olfactory bulb.

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    Dong, Qi; Du, Liping; Zhuang, Liujing; Li, Rong; Liu, Qingjun; Wang, Ping

    2013-11-15

    The mammalian olfactory system has merits of higher sensitivity, selectivity and faster response than current electronic nose system based on chemical sensor array. It is advanced and feasible to detect and discriminate odors by mammalian olfactory system. The purpose of this study is to develop a novel bioelectronic nose based on the brain-machine interface (BMI) technology for odor detection by in vivo electrophysiological measurements of olfactory bulb. In this work, extracellular potentials of mitral/tufted (M/T) cells in olfactory bulb (OB) were recorded by implanted 16-channel microwire electrode arrays. The odor-evoked response signals were analyzed. We found that neural activities of different neurons showed visible different firing patterns both in temporal features and rate features when stimulated by different small molecular odorants. The detection low limit is below 1 ppm for some specific odors. Odors were classified by an algorithm based on population vector similarity and support vector machine (SVM). The results suggested that the novel bioelectonic nose was sensitive to odorant stimuli. The best classifying accuracy was up to 95%. With the development of the BMI and olfactory decoding methods, we believe that this system will represent emerging and promising platforms for wide applications in medical diagnosis and security fields.

  6. Mating behavior induces changes of expression of Fos protein, plasma testosterone and androgen receptors in the accessory olfactory bulb (AOB) of the male mandarin vole Microtus mandarinus

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    Fengqin HE, Fadao TAI

    2009-01-01

    In order to investigate the neuroendocrine mechanism of the mating behavior in the adult male mandarin voles Microtus mandarinus, the radioimmunoassay (RIA) and immunohistochemistry methods were used to investigate the differences in plasma testosterone (T) concentrations and distribution of T immunoreactive neurons (T-IRs), androgen receptor immunoreactive neurons (AR-IRs) and Fos protein immunoreactive neurons (Fos-IRs) in the accessory olfactory bulb (AOB) and the main olfactory bulb (MOB)...

  7. Inducible and targeted deletion of the ERK5 MAP kinase in adult neurogenic regions impairs adult neurogenesis in the olfactory bulb and several forms of olfactory behavior.

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    Yung-Wei Pan

    Full Text Available Although adult-born neurons in the subventricular zone (SVZ and olfactory bulb (OB have been extensively characterized at the cellular level, their functional impact on olfactory behavior is still highly controversial with many conflicting results reported in the literature. Furthermore, signaling mechanisms regulating adult SVZ/OB neurogenesis are not well defined. Here we report that inducible and targeted deletion of erk5, a MAP kinase selectively expressed in the adult neurogenic regions of the adult brain, impairs adult neurogenesis in the SVZ and OB of transgenic mice. Although erk5 deletion had no effect on olfactory discrimination among discrete odorants in the habituation/dishabituation assay, it reduced short-term olfactory memory as well as detection sensitivity to odorants and pheromones including those evoking aggression and fear. Furthermore, these mice show impaired acquisition of odor-cued associative olfactory learning, a novel phenotype that had not been previously linked to adult neurogenesis. These data suggest that ERK5 MAP kinase is a critical kinase signaling pathway regulating adult neurogenesis in the SVZ/OB, and provide strong evidence supporting a functional role for adult neurogenesis in several distinct forms of olfactory behavior.

  8. Multiple conductances cooperatively regulate spontaneous bursting in mouse olfactory bulb external tufted cells.

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    Liu, Shaolin; Shipley, Michael T

    2008-02-13

    External tufted (ET) cells are juxtaglomerular neurons that spontaneously generate bursts of action potentials, which persist when fast synaptic transmission is blocked. The intrinsic mechanism of this autonomous bursting is unknown. We identified a set of voltage-dependent conductances that cooperatively regulate spontaneous bursting: hyperpolarization-activated inward current (I(h)), persistent Na+ current (I(NaP)), low-voltage-activated calcium current (I(L/T)) mediated by T- and/or L-type Ca2+ channels, and large-conductance Ca2+-dependent K+ current (I(BK)). I(h) is important in setting membrane potential and depolarizes the cell toward the threshold of I(NaP) and I(T/L), which are essential to generate the depolarizing envelope that is crowned by a burst of action potentials. Action potentials depolarize the membrane and induce Ca2+ influx via high-voltage-activated Ca2+ channels (I(HVA)). The combined depolarization and increased intracellular Ca2+ activates I(BK), which terminates the burst by hyperpolarizing the membrane. Hyperpolarization activates I(h) and the cycle is regenerated. A novel finding is the role of L-type Ca2+ channels in autonomous ET cells bursting. A second novel feature is the role of BK channels, which regulate burst duration. I(L) and I(BK) may go hand-in-hand, the slow inactivation of I(L) requiring I(BK)-dependent hyperpolarization to deactivate inward conductances and terminate the burst. ET cells receive monosynaptic olfactory nerve input and drive the major inhibitory interneurons of the glomerular circuit. Modulation of the conductances identified here can regulate burst frequency, duration, and spikes per burst in ET cells and thus significantly shape the impact of glomerular circuits on mitral and tufted cells, the output channels of the olfactory bulb.

  9. Role of intraglomerular circuits in shaping temporally structured responses to naturalistic inhalation-driven sensory input to the olfactory bulb.

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    Carey, Ryan M; Sherwood, William Erik; Shipley, Michael T; Borisyuk, Alla; Wachowiak, Matt

    2015-05-01

    Olfaction in mammals is a dynamic process driven by the inhalation of air through the nasal cavity. Inhalation determines the temporal structure of sensory neuron responses and shapes the neural dynamics underlying central olfactory processing. Inhalation-linked bursts of activity among olfactory bulb (OB) output neurons [mitral/tufted cells (MCs)] are temporally transformed relative to those of sensory neurons. We investigated how OB circuits shape inhalation-driven dynamics in MCs using a modeling approach that was highly constrained by experimental results. First, we constructed models of canonical OB circuits that included mono- and disynaptic feedforward excitation, recurrent inhibition and feedforward inhibition of the MC. We then used experimental data to drive inputs to the models and to tune parameters; inputs were derived from sensory neuron responses during natural odorant sampling (sniffing) in awake rats, and model output was compared with recordings of MC responses to odorants sampled with the same sniff waveforms. This approach allowed us to identify OB circuit features underlying the temporal transformation of sensory inputs into inhalation-linked patterns of MC spike output. We found that realistic input-output transformations can be achieved independently by multiple circuits, including feedforward inhibition with slow onset and decay kinetics and parallel feedforward MC excitation mediated by external tufted cells. We also found that recurrent and feedforward inhibition had differential impacts on MC firing rates and on inhalation-linked response dynamics. These results highlight the importance of investigating neural circuits in a naturalistic context and provide a framework for further explorations of signal processing by OB networks.

  10. 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.

  11. Age-Dependent Neurogenesis and Neuron Numbers within the Olfactory Bulb and Hippocampus of Homing Pigeons

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    Meskenaite, Virginia; Krackow, Sven; Lipp, Hans-Peter

    2016-01-01

    Many birds are supreme long-distance navigators that develop their navigational ability in the first months after fledgling but update the memorized environmental information needed for navigation also later in life. We studied the extent of juvenile and adult neurogenesis that could provide such age-related plasticity in brain regions known to mediate different mechanisms of pigeon homing: the olfactory bulb (OB), and the triangular area of the hippocampal formation (HP tr). Newly generated neurons (visualized by doublecortin, DCX) and mature neurons were counted stereologically in 35 pigeon brains ranging from 1 to 168 months of age. At the age of 1 month, both areas showed maximal proportions of DCX positive neurons, which rapidly declined during the first year of life. In the OB, the number of DCX-positive periglomerular neurons declined further over time, but the number of mature periglomerular cells appeared unchanged. In the hippocampus, the proportion of DCX-positive neurons showed a similar decline yet to a lesser extent. Remarkably, in the triangular area of the hippocampus, the oldest birds showed nearly twice the number of neurons as compared to young adult pigeons, suggesting that adult born neurons in these regions expanded the local circuitry even in aged birds. This increase might reflect navigational experience and, possibly, expanded spatial memory. On the other hand, the decrease of juvenile neurons in the aging OB without adding new circuitry might be related to the improved attachment to the loft characterizing adult and old pigeons. PMID:27445724

  12. Rhythm sequence through the olfactory bulb layers during the time window of a respiratory cycle.

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    Buonviso, Nathalie; Amat, Corine; Litaudon, Philippe; Roux, Stephane; Royet, Jean-Pierre; Farget, Vincent; Sicard, Gilles

    2003-05-01

    The mammalian olfactory bulb is characterized by prominent oscillatory activity of its local field potentials. Breathing imposes the most important rhythm. Other rhythms have been described in the beta- and gamma-frequency ranges. We recorded unitary activities in different bulbar layers simultaneously with local field potentials in order to examine the different relationships existing between (i) breathing and field potential oscillations, and (ii) breathing and spiking activity of different cell types. We show that, whatever the layer, odour-induced gamma oscillations always occur around the transition point between inhalation and exhalation while beta oscillations appear during early exhalation and may extend up to the end of inhalation. By contrast, unitary activities exhibit different characteristics according to the layer. They vary in (i) their temporal relationship with respect to the respiratory cycle; (ii) their spike rates; (iii) their temporal patterns defined according to the respiratory cycle. The time window of a respiratory cycle might thus be split into three main epochs based on the deceleration of field potential rhythms (from gamma to beta oscillations) and a simultaneous gradient of spike discharge frequencies ranging from 180 to 30 Hz. We discuss the possibility that each rhythm could serve different functions as priming, gating or tuning for the bulbar network.

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

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    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

  14. 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.

  15. Regional Specializations of the PAZ Proteomes Derived from Mouse Hippocampus, Olfactory Bulb and Cerebellum

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    Jens Weingarten

    2015-05-01

    Full Text Available Neurotransmitter release as well as structural and functional dynamics at the presynaptic active zone (PAZ comprising synaptic vesicles attached to the presynaptic plasma membrane are mediated and controlled by its proteinaceous components. Here we describe a novel experimental design to immunopurify the native PAZ-complex from individual mouse brain regions such as olfactory bulb, hippocampus, and cerebellum with high purity that is essential for comparing their proteome composition. Interestingly, quantitative immunodetection demonstrates significant differences in the abundance of prominent calcium-dependent PAZ constituents. Furthermore, we characterized the proteomes of the immunoisolated PAZ derived from the three brain regions by mass spectrometry. The proteomes of the release sites from the respective regions exhibited remarkable differences in the abundance of a large variety of PAZ constituents involved in various functional aspects of the release sites such as calcium homeostasis, synaptic plasticity and neurogenesis. On the one hand, our data support an identical core architecture of the PAZ for all brain regions and, on the other hand, demonstrate that the proteinaceous composition of their presynaptic active zones vary, suggesting that changes in abundance of individual proteins strengthen the ability of the release sites to adapt to specific functional requirements.

  16. Persistent Structural Plasticity Optimizes Sensory Information Processing in the Olfactory Bulb.

    Science.gov (United States)

    Sailor, Kurt A; Valley, Matthew T; Wiechert, Martin T; Riecke, Hermann; Sun, Gerald J; Adams, Wayne; Dennis, James C; Sharafi, Shirin; Ming, Guo-Li; Song, Hongjun; Lledo, Pierre-Marie

    2016-07-20

    In the mammalian brain, the anatomical structure of neural circuits changes little during adulthood. As a result, adult learning and memory are thought to result from specific changes in synaptic strength. A possible exception is the olfactory bulb (OB), where activity guides interneuron turnover throughout adulthood. These adult-born granule cell (GC) interneurons form new GABAergic synapses that have little synaptic strength plasticity. In the face of persistent neuronal and synaptic turnover, how does the OB balance flexibility, as is required for adapting to changing sensory environments, with perceptual stability? Here we show that high dendritic spine turnover is a universal feature of GCs, regardless of their developmental origin and age. We find matching dynamics among postsynaptic sites on the principal neurons receiving the new synaptic inputs. We further demonstrate in silico that this coordinated structural plasticity is consistent with stable, yet flexible, decorrelated sensory representations. Together, our study reveals that persistent, coordinated synaptic structural plasticity between interneurons and principal neurons is a major mode of functional plasticity in the OB.

  17. Regional Specializations of the PAZ Proteomes Derived from Mouse Hippocampus, Olfactory Bulb and Cerebellum

    Science.gov (United States)

    Weingarten, Jens; Laßek, Melanie; Mueller, Benjamin F.; Rohmer, Marion; Baeumlisberger, Dominic; Beckert, Benedikt; Ade, Jens; Gogesch, Patricia; Acker-Palmer, Amparo; Karas, Michael; Volknandt, Walter

    2015-01-01

    Neurotransmitter release as well as structural and functional dynamics at the presynaptic active zone (PAZ) comprising synaptic vesicles attached to the presynaptic plasma membrane are mediated and controlled by its proteinaceous components. Here we describe a novel experimental design to immunopurify the native PAZ-complex from individual mouse brain regions such as olfactory bulb, hippocampus, and cerebellum with high purity that is essential for comparing their proteome composition. Interestingly, quantitative immunodetection demonstrates significant differences in the abundance of prominent calcium-dependent PAZ constituents. Furthermore, we characterized the proteomes of the immunoisolated PAZ derived from the three brain regions by mass spectrometry. The proteomes of the release sites from the respective regions exhibited remarkable differences in the abundance of a large variety of PAZ constituents involved in various functional aspects of the release sites such as calcium homeostasis, synaptic plasticity and neurogenesis. On the one hand, our data support an identical core architecture of the PAZ for all brain regions and, on the other hand, demonstrate that the proteinaceous composition of their presynaptic active zones vary, suggesting that changes in abundance of individual proteins strengthen the ability of the release sites to adapt to specific functional requirements.

  18. The Adult Ventricular-Subventricular Zone (V-SVZ) and Olfactory Bulb (OB) Neurogenesis.

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    Lim, Daniel A; Alvarez-Buylla, Arturo

    2016-05-02

    A large population of neural stem/precursor cells (NSCs) persists in the ventricular-subventricular zone (V-SVZ) located in the walls of the lateral brain ventricles. V-SVZ NSCs produce large numbers of neuroblasts that migrate a long distance into the olfactory bulb (OB) where they differentiate into local circuit interneurons. Here, we review a broad range of discoveries that have emerged from studies of postnatal V-SVZ neurogenesis: the identification of NSCs as a subpopulation of astroglial cells, the neurogenic lineage, new mechanisms of neuronal migration, and molecular regulators of precursor cell proliferation and migration. It has also become evident that V-SVZ NSCs are regionally heterogeneous, with NSCs located in different regions of the ventricle wall generating distinct OB interneuron subtypes. Insights into the developmental origins and molecular mechanisms that underlie the regional specification of V-SVZ NSCs have also begun to emerge. Other recent studies have revealed new cell-intrinsic molecular mechanisms that enable lifelong neurogenesis in the V-SVZ. Finally, we discuss intriguing differences between the rodent V-SVZ and the corresponding human brain region. The rapidly expanding cellular and molecular knowledge of V-SVZ NSC biology provides key insights into postnatal neural development, the origin of brain tumors, and may inform the development regenerative therapies from cultured and endogenous human neural precursors.

  19. 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

  20. Early in vivo Effects of the Human Mutant Amyloid-β Protein Precursor (hAβPPSwInd) on the Mouse Olfactory Bulb.

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    Rusznák, Zoltán; Kim, Woojin Scott; Hsiao, Jen-Hsiang T; Halliday, Glenda M; Paxinos, George; Fu, YuHong

    2016-01-01

    The amyloid-β protein precursor (AβPP) has long been linked to Alzheimer's disease (AD). Using J20 mice, which express human AβPP with Swedish and Indiana mutations, we studied early pathological changes in the olfactory bulb. The presence of AβPP/amyloid-β (Aβ) was examined in mice aged 3 months (before the onset of hippocampal Aβ deposition) and over 5 months (when hippocampal Aβ deposits are present). The number of neurons, non-neurons, and proliferating cells was assessed using the isotropic fractionator method. Our results demonstrate that although AβPP is overexpressed in some of the mitral cells, widespread Aβ deposition and microglia aggregates are not prevalent in the olfactory bulb. The olfactory bulbs of the younger J20 group harbored significantly fewer neurons than those of the age-matched wild-type mice (5.57±0.13 million versus 6.59±0.36 million neurons; p = 0.011). In contrast, the number of proliferating cells was higher in the young J20 than in the wild-type group (i.e., 6617±425 versus 4455±623 cells; p = 0.011). A significant increase in neurogenic activity was also observed in the younger J20 olfactory bulb. In conclusion, our results indicate that (1) neurons participating in the mouse olfactory function overexpress AβPP; (2) the cellular composition of the young J20 olfactory bulb is different from that of wild-type littermates; (3) these differences may reflect altered neurogenic activity and/or delayed development of the J20 olfactory system; and (4) AβPP/Aβ-associated pathological changes that take place in the J20 hippocampus and olfactory bulb are not identical.

  1. Dichotomous Distribution of Putative Cholinergic Interneurons in Mouse Accessory Olfactory Bulb

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    Marking, Sarah; Krosnowski, Kurt; Ogura, Tatsuya; Lin, Weihong

    2017-01-01

    Sensory information processing in the olfactory bulb (OB) relies on diverse populations of bulbar interneurons. In rodents, the accessory OB (AOB) is divided into two bulbar regions, the anterior (aAOB) and posterior (pAOB), which differ substantially in their circuitry connections and associated behaviors. We previously identified and characterized a large number of morphologically diverse cholinergic interneurons in the main OB (MOB) using transgenic mice to visualize the cell bodies of choline acetyltransferase (ChAT-expressing neurons and immunolabeling (Krosnowski et al., 2012)). However, whether there are cholinergic neurons in the AOB is controversial and there is no detailed characterization of such neurons. Using the same line of ChAT(bacterial artificial chromosome, BAC)-enhanced green fluorescent protein (eGFP) transgenic mice, we investigated cholinergic neurons in the AOB. We found significant differences in the number and location of GFP-expressing (GFP+), putative cholinergic interneurons between the aAOB and pAOB. The highest numbers of GFP+ interneurons were found in the aAOB glomerular layer (aGL) and pAOB mitral/tufted cell layer (pMCL). We also noted a high density of GFP+ interneurons encircling the border region of the pMCL. Interestingly, a small subset of glomeruli in the middle of the GL receives strong MCL GFP+ nerve processes. These local putative cholinergic-innervated glomeruli are situated just outside the aGL, setting the boundary between the pGL and aGL. Many but not all GFP+ neurons in the AOB were weakly labeled with antibodies against ChAT and vesicular acetylcholine transporter (VAChT). We further determined if these GFP+ interneurons differ from other previously characterized interneuron populations in the AOB and found that AOB GFP+ interneurons express neither GABAergic nor dopaminergic markers and most also do not express the glutamatergic marker. Similar to the cholinergic interneurons of the MOB, some AOB GFP+ interneurons

  2. Calretinin-Periglomerular Interneurons in Mice Olfactory Bulb: Cells of Few Words.

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    Fogli Iseppe, Alex; Pignatelli, Angela; Belluzzi, Ottorino

    2016-01-01

    Within the olfactory bulb (OB), periglomerular (PG) cells consist of various types of interneurons, generally classified by their chemical properties such as neurotransmitter and calcium binding proteins. Calretinin (CR) characterizes morphologically and functionally the more numerous and one of the less known subpopulation of PG cells in the OB. Using of transgenic mice expressing eGFP under the CR promoter, we have tried to obtain the first functional characterization of these cells. Electrophysiological recordings were made in these cells using the patch-clamp technique in thin slices. Using ion substitution methods and specific blockers, we dissected the main voltage-dependent conductances present, obtaining a complete kinetic description for each of them. The more peculiar property of these cells from the electrophysiological point of view is the presence only of a single K-current, A-type - there is no trace of delayed rectifier or of Ca-dependent K-current. Other currents identified, isolated and fully characterized are a fast sodium current, a small L-type calcium current, and an inward rectifier, h-type cationic current. As a consequence of the peculiar complement of voltage-dependent conductances present in these cells, and in particular the absence of delayed-rectifier potassium currents, under the functional point of view these cells present two interesting properties. First, in response to prolonged depolarisations, after the inactivation of the A-current these cells behave as a purely ohmic elements, showing no outward rectification. Second, the CR cells studied can respond only with a single action potential to excitatory inputs; since they send inhibitory synapses to projection neurones, they seem to be designed to inhibit responses of the main neurones to isolated, random excitatory signals, rapidly losing their vetoing effect in response to more structured, repetitive excitatory signals. We propose that a possible role for these rather untalkative

  3. Generation of GABAergic and dopaminergic interneurons from endogenous embryonic olfactory bulb precursor cells.

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    Vergaño-Vera, Eva; Yusta-Boyo, María J; de Castro, Fernando; Bernad, Antonio; de Pablo, Flora; Vicario-Abejón, Carlos

    2006-11-01

    During the embryonic period, many olfactory bulb (OB) interneurons arise in the lateral ganglionic eminence (LGE) from precursor cells expressing Dlx2, Gsh2 and Er81 transcription factors. Whether GABAergic and dopaminergic interneurons are also generated within the embryonic OB has not been studied thoroughly. In contrast to abundant Dlx2 and Gsh2 expression in ganglionic eminences (GE), Dlx2 and Gsh2 proteins are not expressed in the E12.5-13.5 mouse OB, whereas the telencephalic pallial domain marker Pax6 is abundant. We found GABAergic and dopaminergic neurons originating from dividing precursor cells in E13.5 OB and in short-term dissociated cultures prepared from the rostral half of E13.5 OB. In OB cultures, 22% of neurons were GAD+, of which 53% were Dlx2+, whereas none expressed Gsh2. By contrast, 70% of GAD+ cells in GE cultures were Dlx2+ and 16% expressed Gsh2. In E13.5 OB slices transplanted with EGFP-labeled E13.5 OB precursor cells, 31.7% of EGFP+ cells differentiated to GABAergic neurons. OB and LGE precursors transplanted into early postnatal OB migrated and differentiated in distinct patterns. Transplanted OB precursors gave rise to interneurons with dendritic spines in close proximity to synaptophysin-positive boutons. Interneurons were also abundant in differentiating OB neural stem cell cultures; the neurons responded to the neurotrophin Bdnf and expressed presynaptic proteins. In vivo, the Bdnf receptor TrkB colocalized with synaptic proteins at the glomeruli. These findings suggest that, in addition to receiving interneurons from the LGE, the embryonic OB contains molecularly distinct local precursor cells that generate mature GABAergic and dopaminergic neurons.

  4. 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.

  5. Dendritic Arborization Patterns of Small Juxtaglomerular Cell Subtypes within the Rodent Olfactory Bulb

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    Bywalez, Wolfgang G.; Ona-Jodar, Tiffany; Lukas, Michael; Ninkovic, Jovica; Egger, Veronica

    2017-01-01

    Within the glomerular layer of the rodent olfactory bulb, numerous subtypes of local interneurons contribute to early processing of incoming sensory information. Here we have investigated dopaminergic and other small local juxtaglomerular cells in rats and mice and characterized their dendritic arborization pattern with respect to individual glomeruli by fluorescent labeling via patching and reconstruction of dendrites and glomerular contours from two-photon imaging data. Dopaminergic neurons were identified in a transgenic mouse line where the expression of dopamine transporter (DAT) was labeled with GFP. Among the DAT+ cells we found a small short-axon cell (SAC) subtype featuring hitherto undescribed dendritic specializations. These densely ramifying structures clasped mostly around somata of other juxtaglomerular neurons, which were also small, non-dopaminergic and to a large extent non-GABAergic. Clasping SACs were observed also in wild-type mice and juvenile rats. In DAT+ SAC dendrites, single backpropagating action potentials evoked robust calcium entry throughout both clasping and non-clasping compartments. Besides clasping SACs, most other small neurons either corresponded to the classical periglomerular cell type (PGCs), which was never DAT+, or were undersized cells with a small dendritic tree and low excitability. Aside from the presence of clasps in SAC dendrites, many descriptors of dendritic morphology such as the number of dendrites and the extent of branching were not significantly different between clasping SACs and PGCs. However, a detailed morphometric analysis in relation to glomerular contours revealed that the dendrites of clasping SACs arborized mostly in the juxtaglomerular space and never entered more than one glomerulus (if at all), whereas most PGC dendrites were restricted to their parent glomerulus, similar to the apical tufts of mitral cells. These complementary arborization patterns might underlie a highly complementary functional

  6. Afterhyperpolarization (AHP) regulates the frequency and timing of action potentials in the mitral cells of the olfactory bulb: role of olfactory experience.

    Science.gov (United States)

    Duménieu, Maël; Fourcaud-Trocmé, Nicolas; Garcia, Samuel; Kuczewski, Nicola

    2015-05-01

    Afterhyperpolarization (AHP) is a principal feedback mechanism in the control of the frequency and patterning of neuronal firing. In principal projection neurons of the olfactory bulb, the mitral cells (MCs), the AHP is produced by three separate components: classical potassium-mediated hyperpolarization, and the excitatory and inhibitory components, which are generated by the recurrent dendrodendritic synaptic transmission. Precise spike timing is involved in olfactory coding and learning, as well as in the appearance of population oscillatory activity. However, the contribution of the AHP and its components to these processes remains unknown. In this study, we demonstrate that the AHP is developed with the MC firing frequency and is dominated by the potassium component. We also show that recurrent synaptic transmission significantly modifies MC AHP and that the strength of the hyperpolarization produced by the AHP in the few milliseconds preceding the action potential (AP) emission determines MC firing frequency and AP timing. Moreover, we show that the AHP area is larger in younger animals, possibly owing to increased Ca(2+) influx during MC firing. Finally, we show that olfactory experience selectively reduces the early component of the MC AHP (under 25 msec), thus producing a modification of the AP timing limited to the higher firing frequency. On the basis of these results, we propose that the AHP, and its susceptibility to be selectively modulated by the recurrent synaptic transmission and olfactory experience, participate in odor coding and learning by modifying the frequency and pattern of MC firing.

  7. The Origin, Development and Molecular Diversity of Rodent Olfactory Bulb Glutamatergic Neurons Distinguished by Expression of Transcription Factor NeuroD1.

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    Laurent Roybon

    Full Text Available Production of olfactory bulb neurons occurs continuously in the rodent brain. Little is known, however, about cellular diversity in the glutamatergic neuron subpopulation. In the central nervous system, the basic helix-loop-helix transcription factor NeuroD1 (ND1 is commonly associated with glutamatergic neuron development. In this study, we utilized ND1 to identify the different subpopulations of olfactory bulb glutamategic neurons and their progenitors, both in the embryo and postnatally. Using knock-in mice, transgenic mice and retroviral transgene delivery, we demonstrate the existence of several different populations of glutamatergic olfactory bulb neurons, the progenitors of which are ND1+ and ND1- lineage-restricted, and are temporally and regionally separated. We show that the first olfactory bulb glutamatergic neurons produced - the mitral cells - can be divided into molecularly diverse subpopulations. Our findings illustrate the complexity of neuronal diversity in the olfactory bulb and that seemingly homogenous neuronal populations can consist of multiple subpopulations with unique molecular signatures of transcription factors and expressing neuronal subtype-specific markers.

  8. Alteration of sensory-evoked metabolic and oscillatory activities in the olfactory bulb of GLAST-deficient mice

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    Claire eMartin

    2012-01-01

    Full Text Available Astrocytes are key cellular elements in both the tripartite synapse and the neuro-vascular unit. To fulfill this dual role in synaptic activity and metabolism, they express a panel of receptors and transporters that sense glutamate. Among them, the GLT-1 and GLAST transporters are known to regulate extracellular glutamate concentrations at excitatory synapses and consequently modulate glutamate receptor signaling. These major uptake systems are also involved in energy supply to neurons. However, the functional role of GLAST in concurrent regulation of metabolic and neuronal activity is currently unknown. We took advantage of the attractive structural and functional features of the main olfactory bulb to explore the impact of GLAST on sensory information processing while probing both glutamate uptake and neuronal activity in glomeruli and deeper cellular layers respectively. Using odor-evoked 2-deoxyglucose imaging and local field potential recordings in GLAST knock-out mice, we show in vivo that deletion of GLAST alters both glucose uptake and neuronal oscillations in olfactory bulb networks.

  9. Dynamic expression of the pro-dopaminergic transcription factors Pax6 and Dlx2 during postnatal olfactory bulb neurogenesis

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    Antoine ede Chevigny

    2012-02-01

    Full Text Available Olfactory bulb neurogenesis generates neurons that use GABA, dopamine or glutamine as their neurotransmitters throughout life. Regionalized stem cell populations in the periventricular zone (PVZ of the lateral ventricles have been shown to be at the basis of neuronal diversity in the system. For example dopaminergic neurons arise predominantly from neural stem cells residing in the dorsal PVZ and depend on the expression of the transcription factors Pax6 and Dlx2 for their specification. In addition Dlx2 is required for neurogenesis in general. Using targeted in vivo electroporation combined with immuno-fluorescence imaging and micro-array analysis, we provide here detailed spatial and temporal expression data with cellular resolution in this system. We find that all along the neurogenic process Pax6 expression remains restricted to the dorsal PVZ, whereas nearly all neuroblasts express Dlx2, including those of the dorsal lineage which are switched on for Dlx2 when they enter the RMS. These data allow to explain and precise the functions of these 2 genes in post-natal olfactory bulb neurogenesis.

  10. Linear correlation between the number of olfactory sensory neurons expressing a given mouse odorant receptor gene and the total volume of the corresponding glomeruli in the olfactory bulb

    Science.gov (United States)

    Bressel, Olaf Christian; Khan, Mona

    2015-01-01

    ABSTRACT Chemosensory specificity in the main olfactory system of the mouse relies on the expression of ∼1,100 odorant receptor (OR) genes across millions of olfactory sensory neurons (OSNs) in the main olfactory epithelium (MOE), and on the coalescence of OSN axons into ∼3,600 glomeruli in the olfactory bulb. A traditional approach for visualizing OSNs and their axons consists of tagging an OR gene genetically with an axonal marker that is cotranslated with the OR by virtue of an internal ribosome entry site (IRES). Here we report full cell counts for 15 gene‐targeted strains of the OR‐IRES‐marker design coexpressing a fluorescent protein. These strains represent 11 targeted OR genes, a 1% sample of the OR gene repertoire. We took an empirical, “count every cell” strategy: we counted all fluorescent cell profiles with a nuclear profile within the cytoplasm, on all serial coronal sections under a confocal microscope, a total of 685,673 cells in 56 mice at postnatal day 21. We then applied a strain‐specific Abercrombie correction to these OSN counts in order to obtain a closer approximation of the true OSN numbers. We found a 17‐fold range in the average (corrected) OSN number across these 11 OR genes. In the same series of coronal sections, we then determined the total volume of the glomeruli (TGV) formed by coalescence of the fluorescent axons. We found a strong linear correlation between OSN number and TGV, suggesting that TGV can be used as a surrogate measurement for estimating OSN numbers in these gene‐targeted strains. J. Comp. Neurol. 524:199–209, 2016. © 2015 Wiley Periodicals, Inc. PMID:26100963

  11. Slits and Robo-2 regulate the coalescence of subsets of olfactory sensory neuron axons within the ventral region of the olfactory bulb.

    Science.gov (United States)

    Cho, Jin H; Kam, Joseph W K; Cloutier, Jean-François

    2012-11-15

    Olfactory sensory neurons (OSNs) project their axons to second-order neurons in the olfactory bulb (OB) to form a precise glomerular map and these stereotypic connections are crucial for accurate odorant information processing by animals. To form these connections, olfactory sensory neuron (OSN) axons respond to axon guidance molecules that direct their growth and coalescence. We have previously implicated the axon guidance receptor Robo-2 in the accurate coalescence of OSN axons within the dorsal region of the OB (Cho et al., 2011). Herein, we have examined whether Robo-2 and its ligands, the Slits, contribute to the formation of an accurate glomerular map within more ventral regions of the OB. We have ablated expression of Robo-2 in OSNs and assessed the targeting accuracy of axons expressing either the P2 or MOR28 olfactory receptors, which innervate two different regions of the ventral OB. We show that P2-positive axons, which express Robo-2, coalesce into glomeruli more ventrally and form additional glomeruli in the OB of robo-2(lox/lox);OMP-Cre mice. We also demonstrate that Robo-2-mediated targeting of P2 axons along the dorsoventral axis of the OB is controlled by Slit-1 and Slit-3 expression. Interestingly, although MOR28-positive OSNs only express low levels of Robo-2, a reduced number of MOR28-positive glomeruli is observed in the OB of robo-2(lox/lox);OMP-Cre mice. Taken together, our results demonstrate that Slits and Robo-2 are required for the formation of an accurate glomerular map in the ventral region of the OB.

  12. 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.

  13. Lack of effect on sexual behaviour or the development of testicular function after removal of olfactory bulbs in prepubertal boars.

    Science.gov (United States)

    Booth, W D; Baldwin, B A

    1980-01-01

    Bilateral olfactory bulb ablation was carried out surgically on 8 prepubertal Large White boars when they were 10-12 weeks of age. Between 26 weeks and slaughter at 47-49 weeks of age, androgen was determined in peripheral blood plasma of bulbectomized and unoperated control animals. The pigs were exposed to oestrous female pigs to observe mating behaviour, and to alien boars to observe aggressive behaviour. Saliva produced during behaviour tests was extracted with diethyl ether and levels of the pheromonal 16-androstene steroids in the extracts were determined by a colorimetric assay. After slaughter the testes, accessory organs and submaxillary glands were weighed, and pices of tissue together with olfactory epithelium were processed for light microscopy; fructose and zinc were determined in the seminal vesicles. The results showed that, contrary to findings in some rodents, prepubertal bilateral bulbectomy in the male pig had no significant effect on mating or aggressive behaviour, or testicular function in so far as complete spermatogenesis was present and normal levels of androgen and pheromone were maintained together with the integrity of the accessory organs. However, in keeping with findings in other species, the height of the olfactory epithelium was generally reduced in the bulbectomized pigs.

  14. 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.

  15. Neuroanatomical relationships between FMRFamide-immunoreactive components of the nervus terminalis and the topology of olfactory bulbs in teleost fish.

    Science.gov (United States)

    D'Aniello, Biagio; Polese, Gianluca; Luongo, Luciano; Scandurra, Anna; Magliozzi, Laura; Aria, Massimo; Pinelli, Claudia

    2016-04-01

    The nervus terminalis (NT) is the most anterior of the vertebrate cranial nerves. In teleost fish, the NT runs across all olfactory components and shows high morphological variability within this taxon. We compare the anatomical distribution, average number and size of the FMRFamide-immunoreactive (ir) NT cells of fourteen teleost species with different positions of olfactory bulbs (OBs) with respect to the ventral telencephalic area. Based on the topology of the OBs, three different neuroanatomical organizations of the telencephalon can be defined, viz., fish having sessile (Type I), pseudosessile (short stalked; Type II) or stalked (Type III) OBs. Type III topology of OBs appears to be a feature associated with more basal species, whereas Types I and II occur in derived and in basal species. The displacement of the OBs is positively correlated with the peripheral distribution of the FMRFamide-ir NT cells. The number of cells is negatively correlated with the size of the cells. A dependence analysis related to the type of OB topology revealed a positive relationship with the number of cells and with the size of the cells, with Type I and II topologies of OBs showing significantly fewer cells and larger cells than Type III. A dendrogram based on similarities obtained by taking into account all variables under study, i.e., the number and size of the FMRFamide-ir NT cells and the topology of OBs, does not agree with the phylogenetic relationships amongst species, suggesting that divergent or convergent evolutionary phenomena produced the olfactory components studied.

  16. 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, h

  17. Gene expression changes in the olfactory bulb of mice induced by exposure to diesel exhaust are dependent on animal rearing environment.

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    Satoshi Yokota

    Full Text Available There is an emerging concern that particulate air pollution increases the risk of cranial nerve disease onset. Small nanoparticles, mainly derived from diesel exhaust particles reach the olfactory bulb by their nasal depositions. It has been reported that diesel exhaust inhalation causes inflammation of the olfactory bulb and other brain regions. However, these toxicological studies have not evaluated animal rearing environment. We hypothesized that rearing environment can change mice phenotypes and thus might alter toxicological study results. In this study, we exposed mice to diesel exhaust inhalation at 90 µg/m(3, 8 hours/day, for 28 consecutive days after rearing in a standard cage or environmental enrichment conditions. Microarray analysis found that expression levels of 112 genes were changed by diesel exhaust inhalation. Functional analysis using Gene Ontology revealed that the dysregulated genes were involved in inflammation and immune response. This result was supported by pathway analysis. Quantitative RT-PCR analysis confirmed 10 genes. Interestingly, background gene expression of the olfactory bulb of mice reared in a standard cage environment was changed by diesel exhaust inhalation, whereas there was no significant effect of diesel exhaust exposure on gene expression levels of mice reared with environmental enrichment. The results indicate for the first time that the effect of diesel exhaust exposure on gene expression of the olfactory bulb was influenced by rearing environment. Rearing environment, such as environmental enrichment, may be an important contributive factor to causation in evaluating still undefined toxic environmental substances such as diesel exhaust.

  18. 嗅球结构及其对生物节律的调控%Structure and regulation of biological rhythms of olfactory bulb

    Institute of Scientific and Technical Information of China (English)

    徐兴远; 王毅群

    2011-01-01

    Olfactory bulb is a key component of olfaction. Recent researches have found that olfactory bulb regulates the biological rhythms, and it expresses regulatory genes relatively independent of suprachiasmatic nucleus. Based on the research of the structure and regulation of biological rhythms of olfactory bulb, it has become a new focus in basic and clinical medicineto study some nervous system diseases and biological rhythms such as sleep. This article summarizes the structure and the effect on regulating biological rhythms of olfactory bulb.%嗅球是人体控制嗅觉的关键部位.近年来研究发现,嗅球还参与了生物节律的调控,其相对独立于视交叉上核表达节律调控基因.基于嗅球与脑内的神经联系以及其对生物节律调控的作用,深入研究一些神经系统疾病和睡眠等人体自身节律可能会成为基础和临床医学研究的新热点.本文将介绍嗅球的结构,并对其参与调控生物节律的功能进行分析总结.

  19. Functional imaging of olfaction by CBV fMRI in monkeys: insight into the role of olfactory bulb in habituation.

    Science.gov (United States)

    Zhao, Fuqiang; Holahan, Marie A; Houghton, Andrea K; Hargreaves, Richard; Evelhoch, Jeffrey L; Winkelmann, Christopher T; Williams, Donald S

    2015-02-01

    Cerebral blood volume (CBV) fMRI with superparamagnetic iron oxide nanoparticles (USPIO) as contrast agent was used to investigate the odorant-induced olfaction in anesthetized rhesus monkeys. fMRI data were acquired in 24 axial slices covering the entire brain, with isoamyl-acetate as the odor stimulant. For each experiment, multiple fMRI measurements were made during a 1- or 2-h period, with each measurement consisting of a baseline period, a stimulation period, and a recovery period. Three different stimulation paradigms with a stimulation period of 1 min, 2 min, or 8 min, respectively, were used to study the olfactory responses in the olfactory bulb (OB). Odorant-induced CBV increases were observed in the OB of each individual monkey. The spatial and temporal activation patterns were reproducible within and between animals. The sensitivity of CBV fMRI in OB was comparable with the sensitivities reported in previous animal fMRI studies. The CBV responses during the 1-min, 2-min, or 8-min odor stimulation period were relatively stable, and did not show attenuation. The amplitudes of CBV response to the repeated stimuli during the 1- or 2-h period were also stable. The stable CBV response in the OB to both continuous and repeated odor stimuli suggests that the OB may not play a major role in olfactory habituation. The technical approach described in this report can enable more extensive fMRI studies of olfactory processing in OB of both humans and non-human primates.

  20. Functional ultrasound imaging reveals different odor-evoked patterns of vascular activity in the main olfactory bulb and the anterior piriform cortex.

    Science.gov (United States)

    Osmanski, B F; Martin, C; Montaldo, G; Lanièce, P; Pain, F; Tanter, M; Gurden, H

    2014-07-15

    Topographic representation of the outside world is a key feature of sensory systems, but so far it has been difficult to define how the activity pattern of the olfactory information is distributed at successive stages in the olfactory system. We studied odor-evoked activation patterns in the main olfactory bulb and the anterior piriform cortex of rats using functional ultrasound (fUS) imaging. fUS imaging is based on the use of ultrafast ultrasound scanners and detects variations in the local blood volume during brain activation. It makes deep brain imaging of ventral structures, such as the piriform cortex, possible. Stimulation with two different odors (hexanal and pentylacetate) induced the activation of odor-specific zones that were spatially segregated in the main olfactory bulb. Interestingly, the same odorants triggered the activation of the entire anterior piriform cortex, in all layers, with no distinguishable odor-specific areas detected in the power Doppler images. These fUS imaging results confirm the spatial distribution of odor-evoked activity in the main olfactory bulb, and furthermore, they reveal the absence of such a distribution in the anterior piriform cortex at the macroscopic scale in vivo.

  1. Automatic segmentation of odor maps in the mouse olfactory bulb using regularized non-negative matrix factorization.

    Science.gov (United States)

    Soelter, Jan; Schumacher, Jan; Spors, Hartwig; Schmuker, Michael

    2014-09-01

    Segmentation of functional parts in image series of functional activity is a common problem in neuroscience. Here we apply regularized non-negative matrix factorization (rNMF) to extract glomeruli in intrinsic optical signal (IOS) images of the olfactory bulb. Regularization allows us to incorporate prior knowledge about the spatio-temporal characteristics of glomerular signals. We demonstrate how to identify suitable regularization parameters on a surrogate dataset. With appropriate regularization segmentation by rNMF is more resilient to noise and requires fewer observations than conventional spatial independent component analysis (sICA). We validate our approach in experimental data using anatomical outlines of glomeruli obtained by 2-photon imaging of resting synapto-pHluorin fluorescence. Taken together, we show that rNMF provides a straightforward method for problem tailored source separation that enables reliable automatic segmentation of functional neural images, with particular benefit in situations with low signal-to-noise ratio as in IOS imaging.

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

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    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.

  3. 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

  4. Long-term plasticity in the regulation of olfactory bulb activity by centrifugal fibers from piriform cortex.

    Science.gov (United States)

    Cauthron, Joy L; Stripling, Jeffrey S

    2014-07-16

    Olfactory bulb granule cells are activated synaptically via two main pathways. Mitral/tufted (M/T) cells form dendrodendritic synapses on granule cells that can be activated by antidromic stimulation of the lateral olfactory tract (LOT). Centrifugal fibers originating from the association fiber (AF) system in piriform cortex (PC) make axodendritic synapses on granule cells within the granule cell layer (GCL) that can be activated by orthodromic stimulation of AF axons in the PC. We explored functional plasticity in the AF pathway by recording extracellularly from individual M/T cells and presumed granule cells in male Long-Evans rats under urethane anesthesia while testing their response to LOT and AF stimulation. Presumed granule cells driven synaptically by LOT stimulation (type L cells) were concentrated in the superficial half of the GCL and were activated at short latencies, whereas those driven synaptically by AF stimulation (type A cells) were concentrated in the deep half of the GCL and were activated at longer latencies. Type A cells were readily detected only in animals in which the AF input to the GCL had been previously potentiated by repeated high-frequency stimulation. An additional bout of high-frequency stimulation administered under urethane caused an immediate increase in the number of action potentials evoked in type A cells by AF test stimulation and a concomitant increase in inhibition of M/T cells. These results underscore the importance of the role played in olfactory processing by PC regulation of OB activity and document the long-lasting potentiation of that regulation by repeated high-frequency AF activation.

  5. The type 3 adenylyl cyclase is required for the survival and maturation of newly generated granule cells in the olfactory bulb.

    Science.gov (United States)

    Luo, Jie; Chen, Xuanmao; Pan, Yung-Wei; Lu, Song; Xia, Zhengui; Storm, Daniel R

    2015-01-01

    The type 3 adenylyl cyclase (AC3) is localized to olfactory cilia in the main olfactory epithelium (MOE) and primary cilia in the adult mouse brain. Although AC3 has been strongly implicated in odor perception and olfactory sensory neuron (OSN) targeting, its role in granule cells (GCs), the most abundant interneurons in the main olfactory bulb (MOB), remains largely unknown. Here, we report that the deletion of AC3 leads to a significant reduction in the size of the MOB as well as the level of adult neurogenesis. The cell proliferation and cell cycle in the subventricular zone (SVZ), however, are not suppressed in AC3-/- mice. Furthermore, AC3 deletion elevates the apoptosis of GCs and disrupts the maturation of newly formed GCs. Collectively, our results identify a fundamental role for AC3 in the development of adult-born GCs in the MOB.

  6. The type 3 adenylyl cyclase is required for the survival and maturation of newly generated granule cells in the olfactory bulb.

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    Jie Luo

    Full Text Available The type 3 adenylyl cyclase (AC3 is localized to olfactory cilia in the main olfactory epithelium (MOE and primary cilia in the adult mouse brain. Although AC3 has been strongly implicated in odor perception and olfactory sensory neuron (OSN targeting, its role in granule cells (GCs, the most abundant interneurons in the main olfactory bulb (MOB, remains largely unknown. Here, we report that the deletion of AC3 leads to a significant reduction in the size of the MOB as well as the level of adult neurogenesis. The cell proliferation and cell cycle in the subventricular zone (SVZ, however, are not suppressed in AC3-/- mice. Furthermore, AC3 deletion elevates the apoptosis of GCs and disrupts the maturation of newly formed GCs. Collectively, our results identify a fundamental role for AC3 in the development of adult-born GCs in the MOB.

  7. Toxic effects of inhaled manganese on the olfactory bulb: an ultrastructural approach in mice.

    Science.gov (United States)

    Colin-Barenque, L; Souza-Gallardo, L M; Fortoul, T I

    2011-01-01

    Olfactory dysfunction is a common symptom reported by patients with neurodegenerative disorders such as Alzheimer's and Parkinson's diseases. Despite the knowledge gathered about the pathology of these diseases, little information has been generated regarding the ultrastructure modifications of the granule cells that regulate the information for odor identification. Swollen organelles and nuclear invaginations identified the exposed mice. Necrosis was evidenced at 4th week of exposure, whereas apoptosis arose at 8th week of exposure. A ruffled electron-dense membrane changes were also found. The changes observed could be explained by the reactive oxygen species generated by manganese and its effects on the membrane's structure and on the cytoskeleton's function. This study contributes to correlate metal air pollution and neurodegenerative changes with olfactory affection.

  8. 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.

  9. Pheromones from males of different familiarity exert divergent effects on adult neurogenesis in the female accessory olfactory bulb.

    Science.gov (United States)

    Wu, Jyun-Han; Han, Yueh-Ting; Yu, Jenn-Yah; Wang, Tsu-Wei

    2013-08-01

    Pheromones from urine of unfamiliar conspecific male animals can reinitiate a female's estrus cycle to cause pregnancy block through the vomeronasal organ (VNO)-accessory olfactory bulb (AOB)-hypothalamic pathway. This phenomenon is called the Bruce effect. Pheromones from the mate of the female, however, do not trigger re-entrance of the estrus cycle because an olfactory memory toward its mate is formed. The activity of the VNO-AOB-hypothalamic pathway is negatively modulated by GABAergic granule cells in the AOB. Since these cells are constantly replenished by neural stem cells in the subventricular zone (SVZ) of the lateral ventricle throughout adulthood and adult neurogenesis is required for mate recognition and fertility, we tested the hypothesis that pheromones from familiar and unfamiliar males may have different effects on adult AOB neurogenesis in female mice. When female mice were exposed to bedding used by a male or lived with one, cell proliferation and neuroblast production in the SVZ were increased. Furthermore, survival of newly generated cells in the AOB was enhanced. This survival effect was transient and mediated by norepinephrine. Interestingly, male bedding-induced newborn cell survival in the AOB but not cell proliferation in the SVZ was attenuated when females were subjected to bedding from an unfamiliar male. Our results indicate that male pheromones from familiar and unfamiliar males exert different effects on neurogenesis in the adult female AOB. Given that adult neurogenesis is required for reproductive behaviors, these divergent pheromonal effects may provide a mechanism for the Bruce effect. © 2013 Wiley Periodicals, Inc. Develop Neurobiol 73: 632-645, 2013. Copyright © 2013 Wiley Periodicals, Inc.

  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. Organization of the main olfactory bulbs of some mammals: musk shrews, moles, hedgehogs, tree shrews, bats, mice, and rats.

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    Kosaka, Katsuko; Kosaka, Toshio

    2004-04-19

    We immunohistochemically examined the organization of the main olfactory bulbs (MOBs) in seven mammalian species, including moles, hedgehogs, tree shrews, bats, and mice as well as laboratory musk shrews and rats. We focused our investigation on two points: 1) whether nidi, particular spheroidal synaptic regions subjacent to glomeruli, which we previously reported for the laboratory musk shrew MOBs, are also present in other animals and 2) whether the compartmental organization of glomeruli and two types of periglomerular cells we proposed for the rat MOBs are general in other animals. The general laminar pattern was similar among these seven species, but discrete nidi and the nidal layer were recognized only in two insectivores, namely, the mole and laboratory musk shrew. Olfactory marker protein-immunoreactive (OMP-IR) axons extended beyond the limits of the glomerular layer (GL) into the superficial region of the external plexiform layer (EPL) or the nidal layer in the laboratory musk shrew, mole, hedgehog, and tree shrew but not in bat, mouse, and rat. We observed, in nidi and the nidal layer in the mole and laboratory musk shrew MOBs, only a few OMP-IR axons. In the hedgehog, another insectivore, OMP-IR processes extending from the glomeruli were scattered and intermingled with calbindin D28k-IR cells at the border between the GL and the EPL. In the superficial region of the EPL of the tree shrew MOBs, there were a small number of tiny glomerulus-like spheroidal structures where OMP-IR axons protruding from glomeruli were intermingled with dendritic branches of surrounding calbindin D28k-IR cells. Furthermore, we recognized the compartmental organization of glomeruli and two types of periglomerular cells in the MOBs of all of the mammals we examined. These structural features are therefore considered to be common and important organizational principles of the MOBs.

  12. Reduction of rat hippocampal calcium-binding protein following commissural, amygdala, septal, perforant path, and olfactory bulb kindling.

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    Baimbridge, K G; Mody, I; Miller, J J

    1985-01-01

    The calcium-binding protein (CaBP) content of the hippocampal formation was determined by radioimmunoassay in control and kindled rats. Kindling of a number of different sites resulted in a reduction in the CaBP content of the hippocampal formation, which was shown immunohistochemically to be restricted to the dentate granule cells and their processes. The maximum decline in CaBP varied with the different kindling sites: perforant path, 33%; commissural path, 32%; septum, 30%; amygdala, 18%; and olfactory bulbs, 15%. There were no changes in the CaBP content of the stimulated areas themselves. In cases where the kindling stimulus was delivered unilaterally (perforant path and amygdala), the maximum decrease in hippocampal CaBP was observed ipsilateral to the site of stimulation when the criterion for full kindling was established (six consecutive stage 5 motor seizures). Further kindling trials were required to produce a similar magnitude decrease in the CaBP content of the contralateral hippocampus. These observations are discussed both in relation to the possible role of CaBP in the establishment of a seizure response to kindling and also as a potential compensatory mechanism that may serve to overcome the epileptogenic effects of kindling.

  13. The transcription factor Sp8 is required for the production of parvalbumin-expressing interneurons in the olfactory bulb.

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    Li, Xiaosu; Sun, Chifei; Lin, Chao; Ma, Tong; Madhavan, Mayur C; Campbell, Kenneth; Yang, Zhengang

    2011-06-08

    Interneurons in the olfactory bulb (OB) represent a heterogeneous population, which are first produced at embryonic stages and persisting into adulthood. Using the BrdU birthdating method combined with immunostaining for several different neuronal markers, we provide the integrated temporal patterns of distinct mouse OB interneuron production from embryonic day 14 to postnatal day 365. We show that although the majority of OB interneuron subtypes continue to be generated throughout life, most subtypes show a similar "bell-like" temporal production pattern with a peak around birth. Tyrosine hydroxylase and calretinin-expressing interneurons are produced at a relatively low rate in the adult OB, while parvalbumin-expressing (PV+) interneuron production is confined to later embryonic and early postnatal stages. We also show that Dlx5/6-expressing progenitors contribute to PV+ interneurons in the OB. Interestingly, all PV+ interneurons in the external plexiform layer (EPL) express the transcription factor Sp8. Genetic ablation of Sp8 by cre/loxP-based recombination severely reduces the number of PV+ interneurons in the EPL of the OB. Our results suggest that Sp8 is required for the normal production of PV+ interneurons in the EPL of the OB. These data expand our understanding of the temporal and molecular regulation of OB interneuron neurogenesis.

  14. Opposite-sex attraction in male mice requires testosterone-dependent regulation of adult olfactory bulb neurogenesis

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    Schellino, Roberta; Trova, Sara; Cimino, Irene; Farinetti, Alice; Jongbloets, Bart C.; Pasterkamp, R. Jeroen; Panzica, Giancarlo; Giacobini, Paolo; De Marchis, Silvia; Peretto, Paolo

    2016-01-01

    Opposite-sex attraction in most mammals depends on the fine-tuned integration of pheromonal stimuli with gonadal hormones in the brain circuits underlying sexual behaviour. Neural activity in these circuits is regulated by sensory processing in the accessory olfactory bulb (AOB), the first central station of the vomeronasal system. Recent evidence indicates adult neurogenesis in the AOB is involved in sex behaviour; however, the mechanisms underlying this function are unknown. By using Semaphorin 7A knockout (Sema7A ko) mice, which show a reduced number of gonadotropin-releasing-hormone neurons, small testicles and subfertility, and wild-type males castrated during adulthood, we demonstrate that the level of circulating testosterone regulates the sex-specific control of AOB neurogenesis and the vomeronasal system activation, which influences opposite-sex cue preference/attraction in mice. Overall, these data highlight adult neurogenesis as a hub for the integration of pheromonal and hormonal cues that control sex-specific responses in brain circuits. PMID:27782186

  15. Interactions between odorant functional group and hydrocarbon structure influence activity in glomerular response modules in the rat olfactory bulb.

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    Johnson, Brett A; Farahbod, Haleh; Leon, Michael

    2005-03-07

    To investigate the effect of odorant hydrocarbon structure on spatial representations in the olfactory bulb systematically, we exposed rats to odorant chemicals possessing one of four different oxygen-containing functional groups on one of five different hydrocarbon backbones. We also used several hydrocarbon odorants lacking other functional groups. Hydrocarbon structural categories included straight-chained, branched, double-bonded, alicyclic, and aromatic features. Activity throughout the entire glomerular layer was measured as uptake of [(14)C]2-deoxyglucose and was mapped into anatomically standardized data matrices for statistical comparisons across different animals. Patterns evoked by straight-chained aliphatic odorants confirmed an association of activity in particular glomerular response modules with particular functional groups. However, the amount of activity in these same modules also was affected significantly by differences in hydrocarbon structure. Thus, the molecular features recognized by receptors projecting to these response modules appear to involve both functional group and hydrocarbon structural elements. In addition, particular benzyl and cyclohexyl odorants evoked activity in dorsal modules previously associated with the ketone functional group, which represents an exception to the rule of one feature per response module that had emerged from our previous studies. These dorsal modules also responded to nitrogen-containing aromatic compounds involving pyridine and pyrazine rings. The unexpected overlap in modular responses to ketones and odorants seemingly unrelated to ketones may reflect some covert shared molecular feature, the existence of odorant sensory neurons with multiple specificities, or a mosaic of sensory neuron projections to these particular modules.

  16. 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.

  17. The production of somatostatin interneurons in the olfactory bulb is regulated by the transcription factor sp8.

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    Xuhua Jiang

    Full Text Available Somatostatin (Som, one of the most concentrated neuropeptides in the brain, is highly expressed in the olfactory bulb (OB. However, the temporal profile by which OB somatostatin-expressing (Som+ interneurons are produced and the molecular mechanisms controlling this profile are totally unknown. In the present study, we found that all the Som+ interneurons in the mouse external plexiform layer (EPL and the rat glomerular layer (GL express the transcription factor Sp8.Using the 5-bromo-2'-deoxyuridine (BrdU birth dating method, combined with immunostaining, we showed that the generation of Som+ interneurons in the mouse and rat OB is confined to the later embryonic and earlier postnatal stages. Within the mouse OB, the production of Som+ interneurons is maximal during late embryogenesis and decreases after birth, whereas the generation of Som+ interneurons is low during embryogenesis and increases gradually after birth in the rat OB. Interestingly, genetic ablation of Sp8 by cre/loxP-based recombination severely reduces the number of Som+ interneurons in the EPL of the mouse OB. Taken together, these results suggest that Sp8 is required for the normal production of Som+ interneurons in the EPL of the mouse OB.

  18. Olfactory bulb transplantation in complete spinal cord injury: axonal regeneration and locomotor recovery

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    Carlos Abraham Arellanes-Chávez

    2015-03-01

    Full Text Available OBJECTIVES: To determine whether the intervention in rats is effective in terms of spinal cord regeneration and locomotor recovery, in order to obtain sufficient evidence to apply the therapy in humans. METHODS: a randomized, controlled, experimental, prospective, randomized trial was conducted, with a sample of 15 adult female Sprague-Dawley rats weighing 250 gr. They were divided into three equal groups, and trained for 2 weeks based on Pavlov's classical conditioning method, to strengthen the muscles of the 4 legs, stimulate the rats mentally, and keep them healthy for the surgery. RESULTS: It was observed that implantation of these cells into the site of injury may be beneficial to the process of spinal cord regeneration after spinal trauma, to mediate secretion of neurotrophic and neuroprotective chemokines, and that the OECs have the ability to bridge the repair site and decrease the formation of gliosis, creating a favorable environment for axonal regeneration. CONCLUSION: It is emphasized that the olfactory ensheathing glial cells possess unique regenerative properties; however, it was not until recently that the activity of promoting central nervous system regeneration was recognized.

  19. High-Field MRI Reveals a Drastic Increase of Hypoxia-Induced Microhemorrhages upon Tissue Reoxygenation in the Mouse Brain with Strong Predominance in the Olfactory Bulb.

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    Hoffmann, Angelika; Kunze, Reiner; Helluy, Xavier; Milford, David; Heiland, Sabine; Bendszus, Martin; Pham, Mirko; Marti, Hugo H

    2016-01-01

    Human pathophysiology of high altitude hypoxic brain injury is not well understood and research on the underlying mechanisms is hampered by the lack of well-characterized animal models. In this study, we explored the evolution of brain injury by magnetic resonance imaging (MRI) and histological methods in mice exposed to normobaric hypoxia at 8% oxygen for 48 hours followed by rapid reoxygenation and incubation for further 24 h under normoxic conditions. T2*-, diffusion-weighted and T2-relaxometry MRI was performed before exposure, immediately after 48 hours of hypoxia and 24 hours after reoxygenation. Cerebral microhemorrhages, previously described in humans suffering from severe high altitude cerebral edema, were also detected in mice upon hypoxia-reoxygenation with a strong region-specific clustering in the olfactory bulb, and to a lesser extent, in the basal ganglia and cerebral white matter. The number of microhemorrhages determined immediately after hypoxia was low, but strongly increased 24 hours upon onset of reoxygenation. Histologically verified microhemorrhages were exclusively located around cerebral microvessels with disrupted interendothelial tight junction protein ZO-1. In contrast, quantitative T2 and apparent-diffusion-coefficient values immediately after hypoxia and after 24 hours of reoxygenation did not show any region-specific alteration, consistent with subtle multifocal but not with regional or global brain edema.

  20. High-Field MRI Reveals a Drastic Increase of Hypoxia-Induced Microhemorrhages upon Tissue Reoxygenation in the Mouse Brain with Strong Predominance in the Olfactory Bulb.

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    Angelika Hoffmann

    Full Text Available Human pathophysiology of high altitude hypoxic brain injury is not well understood and research on the underlying mechanisms is hampered by the lack of well-characterized animal models. In this study, we explored the evolution of brain injury by magnetic resonance imaging (MRI and histological methods in mice exposed to normobaric hypoxia at 8% oxygen for 48 hours followed by rapid reoxygenation and incubation for further 24 h under normoxic conditions. T2*-, diffusion-weighted and T2-relaxometry MRI was performed before exposure, immediately after 48 hours of hypoxia and 24 hours after reoxygenation. Cerebral microhemorrhages, previously described in humans suffering from severe high altitude cerebral edema, were also detected in mice upon hypoxia-reoxygenation with a strong region-specific clustering in the olfactory bulb, and to a lesser extent, in the basal ganglia and cerebral white matter. The number of microhemorrhages determined immediately after hypoxia was low, but strongly increased 24 hours upon onset of reoxygenation. Histologically verified microhemorrhages were exclusively located around cerebral microvessels with disrupted interendothelial tight junction protein ZO-1. In contrast, quantitative T2 and apparent-diffusion-coefficient values immediately after hypoxia and after 24 hours of reoxygenation did not show any region-specific alteration, consistent with subtle multifocal but not with regional or global brain edema.

  1. Main and accessory olfactory bulbs and their projections in the brain anticipate feeding in food-entrained rats.

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    Caba, Mario; Pabello, Marcela; Moreno, Maria Luisa; Meza, Enrique

    2014-10-01

    The olfactory bulb (OB) has a circadian clock independent of the suprachiasmatic nucleus, but very little is known about the functional significance of its oscillations. The OB plays a major role in food intake as it contributes to the evaluation of the hedonic properties of food, it is necessary for a normal pattern of locomotor behavior and their ablation disrupts feeding patterns. Previously we demonstrated that OB of rabbit pups can be entrained by periodic nursing but it was not clear whether food was the entraining signal. Here we hypothesized that OB can be entrained by a food pulse during the day in adult rats under a restricted feeding schedule. Then we expect that OB will have a high activation before food presentation when animals show food anticipatory activity (FAA). To this aim we determined by immunohistochemistry the expression of FOS protein, as an indicator of neural activation, in the mitral and granular cell layers of the main and accessory OB. Additionally we also explored two of the OB brain targets, the piriform cortex (PC) and bed nuclei of the accessory olfactory tract (BAOT), in three groups: ad libitum (ALF), restricted feeding (RF), and fasted rats after restricted feeding (RF-F). In ALF group FOS levels in both main and accessory OB were low during the day and high during the night at the normal onset of the increase of activity, in agreement with previous reports. On the contrary in RF and RF-F groups FOS was high at the time of FAA, just before food presentation, when animals are in a state of high arousal and during food consumption but was low during the night. In their brain targets, we observed a similar pattern as OB in all groups with the only difference being that FOS levels remained high during the night in RF-F group. We conclude that the OB is entrained by food restriction by showing high activation at the time of food presentation, which persists during fasting and impose a similar FOS pattern to the two brain targets

  2. Ultrastructure and synaptic connectivity of main and accessory olfactory bulb efferent projections terminating in the rat anterior piriform cortex and medial amygdala.

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    Park, Sook Kyung; Kim, Jong Ho; Yang, Eun Sun; Ahn, Dong Kuk; Moon, Cheil; Bae, Yong Chul

    2014-09-01

    Neurons in the main olfactory bulb relay peripheral odorant signals to the anterior piriform cortex (aPir), whereas neurons of the accessory olfactory bulb relay pheromone signals to the medial amygdala (MeA), suggesting that they belong to two functionally distinct systems. To help understand how odorant and pheromone signals are further processed in the brain, we investigated the synaptic connectivity of identified axon terminals of these neurons in layer Ia of the aPir and posterodorsal part of the MeA, using anterograde tracing with horseradish peroxidase, quantitative ultrastructural analysis of serial thin sections, and immunogold staining. All identified boutons contained round vesicles and some also contained many large dense core vesicles. The number of postsynaptic dendrites per labeled bouton was significantly higher in the aPir than in the MeA, suggesting higher synaptic divergence at a single bouton level. While a large fraction of identified boutons (29%) in the aPir contacted 2-4 postsynaptic dendrites, only 7% of the identified boutons in the MeA contacted multiple postsynaptic dendrites. In addition, the majority of the identified boutons in the aPir (95%) contacted dendritic spines, whereas most identified boutons in the MeA (64%) contacted dendritic shafts. Identified boutons and many of the postsynaptic dendrites showed glutamate immunoreactivity. These findings suggest that odorant and pheromone signals are processed differently in the brain centers of the main and accessory olfactory systems.

  3. Shared and differential traits in the accessory olfactory bulb of caviomorph rodents with particular reference to the semiaquatic capybara.

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    Suárez, Rodrigo; Santibáñez, Rodrigo; Parra, Daniela; Coppi, Antonio A; Abrahão, Luciana M B; Sasahara, Tais H C; Mpodozis, Jorge

    2011-05-01

    The vomeronasal system is crucial for social and sexual communication in mammals. Two populations of vomeronasal sensory neurons, each expressing Gαi2 or Gαo proteins, send projections to glomeruli of the rostral or caudal accessory olfactory bulb, rAOB and cAOB, respectively. In rodents, the Gαi2- and Gαo-expressing vomeronasal pathways have shown differential responses to small/volatile vs. large/non-volatile semiochemicals, respectively. Moreover, early gene expression suggests predominant activation of rAOB and cAOB neurons in sexual vs. aggressive contexts, respectively. We recently described the AOB of Octodon degus, a semiarid-inhabiting diurnal caviomorph. Their AOB has a cell indentation between subdomains and the rAOB is twice the size of the cAOB. Moreover, their AOB receives innervation from the lateral aspect, contrasting with the medial innervation of all other mammals examined to date. Aiming to relate AOB anatomy with lifestyle, we performed a morphometric study on the AOB of the capybara, a semiaquatic caviomorph whose lifestyle differs remarkably from that of O. degus. Capybaras mate in water and scent-mark their surroundings with oily deposits, mostly for male-male communication. We found that, similar to O. degus, the AOB of capybaras shows a lateral innervation of the vomeronasal nerve, a cell indentation between subdomains and heterogeneous subdomains, but in contrast to O. degus the caudal portion is larger than the rostral one. We also observed that four other caviomorph species present a lateral AOB innervation and a cell indentation between AOB subdomains, suggesting that those traits could represent apomorphies of the group. We propose that although some AOB traits may be phylogenetically conserved in caviomorphs, ecological specializations may play an important role in shaping the AOB.

  4. Dynamic development of the first synapse impinging on adult-born neurons in the olfactory bulb circuit.

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    Katagiri, Hiroyuki; Pallotto, Marta; Nissant, Antoine; Murray, Kerren; Sassoè-Pognetto, Marco; Lledo, Pierre-Marie

    2011-02-01

    The olfactory bulb (OB) receives and integrates newborn interneurons throughout life. This process is important for the proper functioning of the OB circuit and consequently, for the sense of smell. Although we know how these new interneurons are produced, the way in which they integrate into the pre-existing ongoing circuits remains poorly documented. Bearing in mind that glutamatergic inputs onto local OB interneurons are crucial for adjusting the level of bulbar inhibition, it is important to characterize when and how these inputs from excitatory synapses develop on newborn OB interneurons. We studied early synaptic events that lead to the formation and maturation of the first glutamatergic synapses on adult-born granule cells (GCs), the most abundant subtype of OB interneuron. Patch-clamp recordings and electron microscopy (EM) analysis were performed on adult-born interneurons shortly after their arrival in the adult OB circuits. We found that both the ratio of N-methyl-D-aspartate receptor (NMDAR) to α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR), and the number of functional release sites at proximal inputs reached a maximum during the critical period for the sensory-dependent survival of newborn cells, well before the completion of dendritic arborization. EM analysis showed an accompanying change in postsynaptic density shape during the same period of time. Interestingly, the latter morphological changes disappeared in more mature newly-formed neurons, when the NMDAR to AMPAR ratio had decreased and functional presynaptic terminals expressed only single release sites. Together, these findings show that the first glutamatergic inputs to adult-generated OB interneurons undergo a unique sequence of maturation stages.

  5. Odorant Sensory Input Modulates DNA Secondary Structure Formation and Heterogeneous Ribonucleoprotein Recruitment on the Tyrosine Hydroxylase and Glutamic Acid Decarboxylase 1 Promoters in the Olfactory Bulb.

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    Wang, Meng; Cai, Elizabeth; Fujiwara, Nana; Fones, Lilah; Brown, Elizabeth; Yanagawa, Yuchio; Cave, John W

    2017-05-03

    Adaptation of neural circuits to changes in sensory input can modify several cellular processes within neurons, including neurotransmitter biosynthesis levels. For a subset of olfactory bulb interneurons, activity-dependent changes in GABA are reflected by corresponding changes in Glutamate decarboxylase 1 (Gad1) expression levels. Mechanisms regulating Gad1 promoter activity are poorly understood, but here we show that a conserved G:C-rich region in the mouse Gad1 proximal promoter region both recruits heterogeneous nuclear ribonucleoproteins (hnRNPs) that facilitate transcription and forms single-stranded DNA secondary structures associated with transcriptional repression. This promoter architecture and function is shared with Tyrosine hydroxylase (Th), which is also modulated by odorant-dependent activity in the olfactory bulb. This study shows that the balance between DNA secondary structure formation and hnRNP binding on the mouse Th and Gad1 promoters in the olfactory bulb is responsive to changes in odorant-dependent sensory input. These findings reveal that Th and Gad1 share a novel transcription regulatory mechanism that facilitates sensory input-dependent regulation of dopamine and GABA expression.SIGNIFICANCE STATEMENT Adaptation of neural circuits to changes in sensory input can modify several cellular processes within neurons, including neurotransmitter biosynthesis levels. This study shows that transcription of genes encoding rate-limiting enzymes for GABA and dopamine biosynthesis (Gad1 and Th, respectively) in the mammalian olfactory bulb is regulated by G:C-rich regions that both recruit heterogeneous nuclear ribonucleoproteins (hnRNPs) to facilitate transcription and form single-stranded DNA secondary structures associated with repression. hnRNP binding and formation of DNA secondary structure on the Th and Gad1 promoters are mutually exclusive, and odorant sensory input levels regulate the balance between these regulatory features. These findings

  6. 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.

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    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.

  7. 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

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    Aimé, Pascaline; Hegoburu, Chloé; Jaillard, Tristan; Degletagne, Cyril; Garcia, Samuel; Messaoudi, Belkacem; Thevenet, Marc; Lorsignol, Anne; Duchamp, Claude; Mouly, Anne-Marie; Julliard, Andrée Karyn

    2012-01-01

    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. PMID:23251461

  8. A single identified glomerulus in the zebrafish olfactory bulb carries the high-affinity response to death-associated odor cadaverine

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    Dieris, Milan; Ahuja, Gaurav; Krishna, Venkatesh; Korsching, Sigrun I.

    2017-01-01

    The death-associated odor cadaverine, generated by bacteria-mediated decarboxylation of lysine, has been described as the principal activator of a particular olfactory receptor in zebrafish, TAAR13c. Low concentrations of cadaverine activated mainly TAAR13c-expressing olfactory sensory neurons, suggesting TAAR13c as an important element of the neuronal processing pathway linking cadaverine stimulation to a strongly aversive innate behavioral response. Here, we characterized the initial steps of this neuronal pathway. First we identified TAAR13c-expressing cells as ciliated neurons, equivalent to the situation for mammalian taar genes, which shows a high degree of conservation despite the large evolutionary distance between teleost fishes and mammals. Next we identified the target area of cadaverine-responsive OSNs in the olfactory bulb. We report that cadaverine dose-dependently activates a group of dorsolateral glomeruli, at the lowest concentration down to a single invariant glomerulus, situated at the medial border of the dorsolateral cluster. This is the first demonstration of a single stereotyped target glomerulus in the fish olfactory system for a non-pheromone odor. A mix of different amines activates many glomeruli within the same dorsolateral cluster, suggesting this area to function as a general amine response region. PMID:28102357

  9. 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

  10. 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 behavior

  11. Olfactory disturbance in aged rats in association with mitochondrial changes in the olfactory bulb neurons%衰老大鼠嗅觉障碍与嗅球神经元内线粒体的变化

    Institute of Scientific and Technical Information of China (English)

    丁志敏; 赵淑敏

    2005-01-01

    BACKGROUND: Mutation of the mitochondrial DNA may occur during the aging process of organisms, which is especially likely in the central nervous system. Evidences have been obtained that mitochondrial dysfunction may ensue from genetic impairment involved in oxidative phosphorylation, which is accompanied by corresponding morphological changes.OBJECTIVE: To investigate the association between olfactory disturbance and ultrastructural mitochondrial changes in olfactory bulb neurons of aged rats in comparison with young rats.DESIGN: Randomized controlled experiment.SETTING: Department of Internal Medicine, Affiliated Hospital of Chende Medical College and Department of Electron Microscopy of Chende Medical College.MATERIALS: This experiment was conducted in the Department of Electron Microscopy of Chende Medical College between April and December 2002. Sixteen male Wistar rats were divided equally into aged group (> 24 months) with body mass of 300-350 g and young group (6 months) with body mass of 180-220 g.METHODS: The rats in the two groups were anaesthetized by intraperitoneal injection of 10 g/L urethane (1 g/kg) and the chest was opened to insert a tube into the ascending aorta for perfusion with 200 mL of the mixture containing glutaric dialdehyde and paraformaldehyde for fixation.The olfactory bulb was then obtained and sliced, fixed in perosmic acid and embedded. Each layer of the olfactory bulb was observed under optical microscope and ultra-thin sections were prepared for observation under transmission electron microscope.MAIN OUTCOME MEASURES: The stratification of rat olfactory bulb and ultrastructural changes of the mitochondria in the major neurons in the olfactory bulb.REULSTS: No obvious changes were found in the stratification of the olfactory bulb in the two groups. From the exterior to the interior of the olfactory bulb, the olfactory nerve fiber layer, glomerular layer, external plexiform layer, mitral cell lalyer, internal plexiform layer and

  12. Expression of estrogen receptor (ER) -α and -β transcripts in the neonatal and adult rat cerebral cortex, cerebellum, and olfactory bulb

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In the present study expression of estrogen receptor subtype -α (ERα) and -β (ERβ) in the cerebral cortex, cerebellum, and olfactory bulb was investigated and compared between neonatal (1~ 3-days-old) and adult (250~350g) rats, using reverse transcription-polymerase chain reaction (RT-PCR). No ERα transcripts were detectable in the adult cerebellum and olfactory bulb, whereas very weak expression of ERα was present in the adult cerebral cortex. No significant difference in ERβ transcripts was detectable between the neonatal and adult rats. While transcripts for both ER subtypes were co-expressed in these brain areas of neonatal rats, although ERα expression was significantly weaker than ERβ. Even in the cerebral cortex known to contain both ER subtypes in adult rats, ERα transcripts in neonatal rats were much higher than in adult. These observations provide evidence for the existence of different expression patterns of ERα/ERβ transcripts in these three brain areas between the neonatal and adult rats, suggesting that each ER subtype may play a distinct role in the regulation of differentiation, development, and functions of the brain by estrogen.

  13. Noradrenaline-induced enhancement of oscillatory local field potentials in the mouse accessory olfactory bulb does not depend on disinhibition of mitral cells.

    Science.gov (United States)

    Leszkowicz, Emilia; Khan, Selina; Ng, Stephanie; Ved, Nikita; Swallow, Daniel L; Brennan, Peter A

    2012-05-01

    The olfactory bulb differs from other brain regions by its use of bidirectional synaptic transmission at dendrodendritic reciprocal synapses. These reciprocal synapses provide tight coupling of inhibitory feedback from granule cell interneurons to mitral cell projection neurons in the accessory olfactory bulb (AOB), at the first stage of vomeronasal processing. It has been proposed that both the mGluR2 agonist DCG-IV and noradrenaline promote mate recognition memory formation by reducing GABAergic feedback on mitral cells. The resultant mitral cell disinhibition is thought to induce a long-lasting enhancement in the gain of inhibitory feedback from granule to mitral cells, which selectively gates the transmission of the learned chemosensory information. However, we found that local infusions of both noradrenaline and DCG-IV failed to disinhibit AOB neural activity in urethane-anaesthetised mice. DCG-IV infusion had similar effects to the GABA(A) agonist isoguvacine, suggesting that it increased GABAergic inhibition in the AOB rather than reducing it. Noradrenaline infusion into the AOB also failed to disinhibit mitral cells in awake mice despite inducing long-term increases in power of AOB local field potentials, similar to those observed following memory formation. These results suggest that mitral cell disinhibition is not essential for the neural changes in the AOB that underlie mate recognition memory formation in mice.

  14. Brain-derived neurotrophic factor selectively regulates dendritogenesis of parvalbumin-containing interneurons in the main olfactory bulb through the PLCgamma pathway.

    Science.gov (United States)

    Berghuis, Paul; Agerman, Karin; Dobszay, Marton B; Minichiello, Liliana; Harkany, Tibor; Ernfors, Patrik

    2006-11-01

    Molecular mechanisms of neurotrophin signaling on dendrite development and dynamics are only partly understood. To address the role of brain-derived neurotrophic factor (BDNF) in the morphogenesis of GABAergic neurons of the main olfactory bulb, we analyzed mice lacking BDNF, mice carrying neurotrophin-3 (NT3) in the place of BDNF, and TrkB signaling mutant mice with a receptor that can activate phospholipase Cgamma (PLCgamma) but is unable to recruit the adaptors Shc/Frs2. BDNF deletion yielded a compressed olfactory bulb with a significant loss of parvalbumin (PV) immunoreactivity in GABAergic interneurons of the external plexiform layer. Dendrite development of PV-positive interneurons was selectively attenuated by BDNF since other Ca2+ -binding protein-containing neuron populations appeared unaffected. The deficit in PV-positive neurons could be rescued by the NT3/NT3 alleles. The degree of PV immunoreactivity was dependent on BDNF and TrkB recruitment of the adaptor proteins Shc/Frs2. In contrast, PLCgamma signaling from the TrkB receptor was sufficient for dendrite growth in vivo and consistently, blocking PLCgamma prevented BDNF-dependent dendrite development in vitro. Collectively, our results provide genetic evidence that BDNF and TrkB signaling selectively regulate PV expression and dendrite growth in a subset of neurochemically-defined GABAergic interneurons via activation of the PLCgamma pathway.

  15. 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.

  16. 成年大鼠嗅球嗅鞘细胞的纯化实验%Purifying olfactory ensheathing cells from the olfactory bulb of adult rats

    Institute of Scientific and Technical Information of China (English)

    朱仲庚; 吴小涛; 蒋赞利

    2007-01-01

    BACKGROUND: The diversity of purification procedures resulting in various purities of olfactory ensheathing cells (OECs) used for grafting is considered to be relevant in the effectiveness of OECs transplant. It is important to develop a well-defined method which produces OECs of great purity and is easy to unify for the future standardization of research involving OECs.OBJECTIVE: To establish a method being easy to unify for purifying OECs to acquire highly and uniformly enriched population of OECs for standardized studies on cell transplantation.DESIGN: Randomized and controlled experiment.SETTING: Department of Orthopaedics, Affiliated Zhongda Hospital of Southeast University School of Clinical Medicine;Central Laboratory of Southeast University School of Clinical Medicine; Experimental Animal Center of Southeast University School of Clinical Medicine.MATERIALS: This experiment was carried out in the Central Laboratory of Southeast University School of Clinical Medicine from February to August 2006. Twenty-eight adult female SD rats weighing 200-250 g were selected in this study. The main reagents were detailed as follows: DMEM/F-12 (GIBCO); 2.5 g/L trypsin (GIBCO); poly-L-lysine (SIGMA); bovine pituitary extract (BPE, SIGMA); fetal bovine serum (FBS, Sijiqing Biological Agent Co., Ltd., Hangzhou);rabbit anti-low-affinity nerve growth factor receptor (anti-P75, SIGMA); biotinylated goat anti-rabbit IgG (Boster Bioengineering Co., Ltd., Wuhan); methyl thiazolyl tetrazolium (MTT) kit (SIGMA).METHODS: Primary cultures of OECs were separated from adult SD rats olfactory bulbs. At day 8 in vitro, the primary cultures were divided randomly into 4 groups, namely differential adhesion method group, immunoadsorption method group,the modified method group,and control group.①The cell suspension in the modified method group was seeded into uncoated flasks and incubated at 37 ℃ in 0.05 volume fraction of CO2 for 1 hours. The supematants were seeded into flasks that had

  17. Targeted deletion of the ERK5 MAP kinase impairs neuronal differentiation, migration, and survival during adult neurogenesis in the olfactory bulb.

    Directory of Open Access Journals (Sweden)

    Tan Li

    Full Text Available Recent studies have led to the exciting idea that adult-born neurons in the olfactory bulb (OB may be critical for complex forms of olfactory behavior in mice. However, signaling mechanisms regulating adult OB neurogenesis are not well defined. We recently reported that extracellular signal-regulated kinase (ERK 5, a MAP kinase, is specifically expressed in neurogenic regions within the adult brain. This pattern of expression suggests a role for ERK5 in the regulation of adult OB neurogenesis. Indeed, we previously reported that conditional deletion of erk5 in adult neurogenic regions impairs several forms of olfactory behavior in mice. Thus, it is important to understand how ERK5 regulates adult neurogenesis in the OB. Here we present evidence that shRNA suppression of ERK5 in adult neural stem/progenitor cells isolated from the subventricular zone (SVZ reduces neurogenesis in culture. By contrast, ectopic activation of endogenous ERK5 signaling via expression of constitutive active MEK5, an upstream activating kinase for ERK5, stimulates neurogenesis. Furthermore, inducible and conditional deletion of erk5 specifically in the neurogenic regions of the adult mouse brain interferes with cell cycle exit of neuroblasts, impairs chain migration along the rostral migratory stream and radial migration into the OB. It also inhibits neuronal differentiation and survival. These data suggest that ERK5 regulates multiple aspects of adult OB neurogenesis and provide new insights concerning signaling mechanisms governing adult neurogenesis in the SVZ-OB axis.

  18. Differential effect of functional olfactory bulb deafferentation on tyrosine hydroxylase and glutamic acid decarboxylase messenger RNA levels in rodent juxtaglomerular neurons.

    Science.gov (United States)

    Stone, D M; Grillo, M; Margolis, F L; Joh, T H; Baker, H

    1991-09-08

    Expression of the dopaminergic phenotype in olfactory bulb (OB) juxtaglomerular neurons (constituting a population of periglomerular and external tufted cells) is dependent upon functional innervation by peripheral olfactory receptors. Loss of functional input in rodents, by either peripheral deafferentation or deprivation of odorant access, results in a profound decrease in the expression of juxtaglomerular tyrosine hydroxylase (TH). We have examined the effects of such treatments on the expression of the neurotransmitter biosynthetic enzyme glutamic acid decarboxylase (GAD), which is colocalized with TH in the majority of TH-containing juxtaglomerular neurons. Following either chemically induced OB deafferentation in adult mice or unilateral odor deprivation in neonatal rats, steady-state OB GAD messenger RNA levels remained essentially unchanged as assessed by Northern blot analysis 20-40 days after treatment. These results were confirmed by in situ hybridization analysis, which demonstrated a profound loss of juxtaglomerular TH messenger RNA but no accompanying decrease in regionally colocalized GAD message. Since GAD is found in nearly all dopaminergic OB cells, the preservation of juxtaglomerular GAD message implies that olfactory receptor neurons exert a differential transneuronal regulation of TH and GAD gene transcription.

  19. 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.

  20. A comparative study of prenatal development in the olfactory bulb, neocortex and hippocampal region of the precocial mouse Acomys cahirinus and rat.

    Science.gov (United States)

    Brunjes, P C

    1989-09-01

    Unlike the remainder of the rodent subfamily Muridae, Acomys cahirinus (the 'spiny' mouse) is born in a precocial state after a long (39 day) gestation. In this paper, the development of the olfactory bulb, neocortex and hippocampal formation of Acomys from prenatal days 14-34 was examined and the rate of maturation compared with that of its cousin, the laboratory rat (Rattus norvegicus). At the earliest stages examined, Acomys was approximately 2 days less mature than the same post-conception aged rat. The difference between the two species increased: Acomys at 28 days postconception resembled the 22-day rat. By the end of gestation, Acomys and the rat were in a relatively similar developmental state. Therefore, Acomys exhibits a quite different timetable of early maturation which includes a protracted period of relatively slow growth during mid-gestation. As such, it offers many benefits as a subject for studies of both early ontogenesis and the mechanisms which result in species differences.

  1. Mating behavior induces changes of expression of Fos protein, plasma testosterone and androgen receptors in the accessory olfactory bulb (AOB of the male mandarin vole Microtus mandarinus

    Directory of Open Access Journals (Sweden)

    Fengqin HE, Fadao TAI

    2009-08-01

    Full Text Available In order to investigate the neuroendocrine mechanism of the mating behavior in the adult male mandarin voles Microtus mandarinus, the radioimmunoassay (RIA and immunohistochemistry methods were used to investigate the differences in plasma testosterone (T concentrations and distribution of T immunoreactive neurons (T-IRs, androgen receptor immunoreactive neurons (AR-IRs and Fos protein immunoreactive neurons (Fos-IRs in the accessory olfactory bulb (AOB and the main olfactory bulb (MOB following exposure to clean hard-wood shavings (control group, soiled bedding (exposure group or contact with an estrous female (mating group. Results showed that plasma T concentration was significantly higher in the mating group than that in the exposure group, and both the mating group and the exposure group displayed significantly higher plasma T concentration than the control group. T-IRs, AR-IRs and Fos-IRs were investigated with the immunohistochemistry method in granule cell (GC and mitral cell (MC of the MOB and the AOB in the three groups. There were significantly more T-IRs, AR-IRs and Fos-IRs in MC and GC of the AOB in the mating group than that in the exposure group or the control group. T-IRs, AR-IRs and Fos-IRs did not show significant differences between the exposure group and the control group. Furthermore, obvious differences in MC and GC of the MOB were not found among the three groups. The results confirm that both changes of T and AR in the AOB might be underlying mating behavior in the adult male mandarin voles [Current Zoology 55 (4: 288–295, 2009].

  2. 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.

  3. Robo-2 controls the segregation of a portion of basal vomeronasal sensory neuron axons to the posterior region of the accessory olfactory bulb.

    Science.gov (United States)

    Prince, Janet E A; Cho, Jin Hyung; Dumontier, Emilie; Andrews, William; Cutforth, Tyler; Tessier-Lavigne, Marc; Parnavelas, John; Cloutier, Jean-François

    2009-11-11

    The ability of sensory systems to detect and process information from the environment relies on the elaboration of precise connections between sensory neurons in the periphery and second order neurons in the CNS. In mice, the accessory olfactory system is thought to regulate a wide variety of social and sexual behaviors. The expression of the Slit receptors Robo-1 and Robo-2 in vomeronasal sensory neurons (VSNs) suggests they may direct the stereotypic targeting of their axons to the accessory olfactory bulb (AOB). Here, we have examined the roles of Robo-1 and Robo-2 in the formation of connections by VSN axons within the AOB. While Robo-1 is not necessary for the segregation of VSN axons within the anterior and posterior regions of the AOB, Robo-2 is required for the targeting of some basal VSN axons to the posterior region of the AOB but is dispensable for the fasciculation of VSN axons. Furthermore, the specific ablation of Robo-2 expression in VSNs leads to mistargeting of a portion of basal VSN axons to the anterior region of the AOB, indicating that Robo-2 expression is required on projecting VSN axons. Together, these results identify Robo-2 as a receptor that controls the targeting of basal VSN axons to the posterior AOB.

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

    Science.gov (United States)

    Perez de los Cobos Pallares, Fernando; Loebel, Alex; Lukas, Michael

    2016-01-01

    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. PMID:27747107

  5. 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.

  6. 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…

  7. Regarding several points of doubt of the structure of the olfactory bulb: as described by T. Blanes.

    Science.gov (United States)

    Levine, Catherine; Marcillo, Alexander

    2008-07-01

    In order to complement the studies on the fila olfactoria completed by Dr. Santiago Ramón y Cajal, we have included a translation of "Sobre Algunos Puntos Dudosos de la Estructura del Bulbo Olfatorio" by T. Blanes, a student of Dr. Cajal. This work describes in stunning detail additional morphological aspects of the olfactory pathway, including what was at the time the modestly studied neuroglia. The neuroglia of the olfactory system has been revisited in the last several decades for its importance in the field of regenerative neuroscience. Olfactory ensheathing glia has the unique quality of providing ensheathment to neurons which traverse from the central to the peripheral nervous system and are being used as a candidate in present-day transplantation studies to mimic this phenomenon at the dorsal root entry zone after a central nervous system injury. Although this fine work has passed its centennial anniversary since initial publication, it has been widely cited throughout the years, and of recent when Pressler and Stowbridge reported Blanes cell electrophysiological recordings (Neuron V 49, 6; p 889-904, 2006). An English translation the details of what Blanes initially documented with unduplicated precision can now be made available to a wider audience in the field of neuroscience, and is especially important now that more and more present-day studies require a precise and complete understanding of the anatomical structures contained within the olfactory system. (c) 2008 Wiley-Liss, Inc.

  8. Model test and CFD calculation of a cavitating bulb turbine

    Energy Technology Data Exchange (ETDEWEB)

    Necker, J; Aschenbrenner, T, E-mail: joerg.necker@voith.co [Voith Hydro Holding GmbH and Co. KG Alexanderstrasse 11, 89522 Heidenheim (Germany)

    2010-08-15

    The flow in a horizontal shaft bulb turbine is calculated as a two-phase flow with a commercial Computational Fluid Dynamics (CFD-)-code including cavitation model. The results are compared with experimental results achieved at a closed loop test rig for model turbines. On the model test rig, for a certain operating point (i.e. volume flow, net head, blade angle, guide vane opening) the pressure behind the turbine is lowered (i.e. the Thoma-coefficient {sigma} is lowered) and the efficiency of the turbine is recorded. The measured values can be depicted in a so-called {sigma}-break curve or {eta}- {sigma}-diagram. Usually, the efficiency is independent of the Thoma-coefficient up to a certain value. When lowering the Thoma-coefficient below this value the efficiency will drop rapidly. Visual observations of the different cavitation conditions complete the experiment. In analogy, several calculations are done for different Thoma-coefficients {sigma}and the corresponding hydraulic losses of the runner are evaluated quantitatively. For a low {sigma}-value showing in the experiment significant efficiency loss, the the change of volume flow in the experiment was simulated. Besides, the fraction of water vapour as an indication of the size of the cavitation cavity is analyzed qualitatively. The experimentally and the numerically obtained results are compared and show a good agreement. Especially the drop in efficiency can be calculated with satisfying accuracy. This drop in efficiency is of high practical importance since it is one criterion to determine the admissible cavitation in a bulb-turbine. The visual impression of the cavitation in the CFD-analysis is well in accordance with the observed cavitation bubbles recorded on sketches and/or photographs.

  9. Interaction between different cells in an olfactory bulb and synchronous kinematic analysis%嗅球中神经元间的相互作用及同步运动分析

    Institute of Scientific and Technical Information of China (English)

    徐爱蕾; 杜莹; 王如彬

    2013-01-01

    Olfactory bulb plays an important part in signal encoding of an olfactory system. The interaction between excitatory mitral cells and inhibitory granule cells is particularly crucial. Here, the current situation of synchronous oscillation in the network of an olfactory system was firstly introduced. Then, the dynamic models of a mitral cell and a granular cell in the olfactory bulb were built. The simulation figures showed the firing patterns of a single mitral cell, a single granular cell, and these two kinds of cells having a coupling relationship. The results indicated that mitral cells have an excitatory effect on granular cells, and granular cells have an inhibitory effect on mitral cells; the firing pattern varies with different synaptic strength. In addition, simple olfactory network models were built, the influence of ring-like and grid-like neuronal network of granular cells on the synchronization of two mitral cells was analyzed. Different types of firing synchronization were diagnosed by means of ISI-distance method. The numerical analysis indicated that grid-like neuronal network of granular cells can make mitral cells synchronize better.%嗅球对嗅觉信息的处理是嗅觉系统信号编码的一个重要环节,其中兴奋性的僧帽细胞(Mitral Cell,MC)与抑制性的颗粒细胞(Granular Cell,GC)的相互作用尤为关键.本文首先介绍了嗅觉系统网络中关于同步振荡的研究现状,然后建立嗅球中僧帽细胞及颗粒细胞的动力学模型,仿真得到了单个僧帽细胞、颗粒细胞以及僧帽细胞与颗粒细胞在耦合条件下神经元的发放模式.结果表明,僧帽细胞对颗粒细胞有兴奋性作用,而颗粒细胞对僧帽细胞有抑制性作用,细胞放电序列随着突触连接强度的改变而改变.此外,建立简单的嗅觉网络模型,分析了当颗粒细胞分别构成环形和网格状两种拓扑结构时,不同网络对两个僧帽细胞同步性的影响,用同步性指标ISI

  10. Optogenetic Activation of Accessory Olfactory Bulb Input to the Forebrain Differentially Modulates Investigation of Opposite versus Same-Sex Urinary Chemosignals and Stimulates Mating in Male Mice

    Science.gov (United States)

    McCarthy, Elizabeth A.; Korzan, Wayne J.; Doctor, Danielle; Han, Xue; Baum, Michael J.

    2017-01-01

    Abstract Surgical or genetic disruption of vomeronasal organ (VNO)-accessory olfactory bulb (AOB) function previously eliminated the ability of male mice to processes pheromones that elicit territorial behavior and aggression. By contrast, neither disruption significantly affected mating behaviors, although VNO lesions reduced males’ investigation of nonvolatile female pheromones. We explored the contribution of VNO-AOB pheromonal processing to male courtship using optogenetic activation of AOB projections to the forebrain. Protocadherin-Cre male transgenic mice received bilateral AOB infections with channelrhodopsin2 (ChR2) viral vectors, and an optical fiber was implanted above the AOB. In olfactory choice tests, males preferred estrous female urine (EFU) over water; however, this preference was eliminated when diluted (5%) EFU was substituted for 100% EFU. Optogenetic AOB activation concurrent with nasal contact significantly augmented males’ investigation compared to 5% EFU alone. Conversely, concurrent optogenetic AOB activation significantly reduced males’ nasal investigation of diluted urine from gonadally intact males (5% IMU) compared to 5% IMU alone. These divergent effects of AOB optogenetic activation were lost when males were prevented from making direct nasal contact. Optogenetic AOB stimulation also failed to augment males’ nasal investigation of deionized water or of food odors. Finally, during mating tests, optogenetic AOB stimulation delivered for 30 s when the male was in physical contact with an estrous female significantly facilitated the occurrence of penile intromission. Our results suggest that VNO-AOB signaling differentially modifies males’ motivation to seek out female vs male urinary pheromones while augmenting males’ sexual arousal leading to intromission and improved reproductive performance. PMID:28374006

  11. Optical dissection of odor information processing in vivo using GCaMPs expressed in specified cell types of the olfactory bulb.

    Science.gov (United States)

    Wachowiak, Matt; Economo, Michael N; Díaz-Quesada, Marta; Brunert, Daniela; Wesson, Daniel W; White, John A; Rothermel, Markus

    2013-03-20

    Understanding central processing requires precise monitoring of neural activity across populations of identified neurons in the intact brain. In the present study, we used recently optimized variants of the genetically encoded calcium sensor GCaMP (GCaMP3 and GCaMPG5G) to image activity among genetically and anatomically defined neuronal populations in the olfactory bulb (OB), including two types of GABAergic interneurons (periglomerular [PG] and short axon [SA] cells) and OB output neurons (mitral/tufted [MT] cells) projecting to the piriform cortex. We first established that changes in neuronal spiking can be related accurately to GCaMP fluorescence changes via a simple quantitative relationship over a large dynamic range. We next used in vivo two-photon imaging from individual neurons and epifluorescence signals reflecting population-level activity to investigate the spatiotemporal representation of odorants across these neuron types in anesthetized and awake mice. Under anesthesia, individual PG and SA cells showed temporally simple responses and little spontaneous activity, whereas MT cells were spontaneously active and showed diverse temporal responses. At the population level, response patterns of PG, SA, and MT cells were surprisingly similar to those imaged from sensory inputs, with shared odorant-specific topography across the dorsal OB and inhalation-coupled temporal dynamics. During wakefulness, PG and SA cell responses increased in magnitude but remained temporally simple, whereas those of MT cells changed to complex spatiotemporal patterns reflecting restricted excitation and widespread inhibition. These results suggest multiple circuit elements with distinct roles in transforming odor representations in the OB and provide a framework for further study of early olfactory processing using optical and genetic tools.

  12. Neonatal handling and the maternal odor preference in rat pups: involvement of monoamines and cyclic AMP response element-binding protein pathway in the olfactory bulb.

    Science.gov (United States)

    Raineki, C; De Souza, M A; Szawka, R E; Lutz, M L; De Vasconcellos, L F T; Sanvitto, G L; Izquierdo, I; Bevilaqua, L R; Cammarota, M; Lucion, A B

    2009-03-03

    Early-life environmental events, such as the handling procedure, can induce long-lasting alterations upon several behavioral and neuroendocrine systems. However, the changes within the pups that could be causally related to the effects in adulthood are still poorly understood. In the present study, we analyzed the effects of neonatal handling on behavioral (maternal odor preference) and biochemical (cyclic AMP response element-binding protein (CREB) phosphorylation, noradrenaline (NA), and serotonin (5-HT) levels in the olfactory bulb (OB)) parameters in 7-day-old male and female rat pups. Repeated handling (RH) abolished preference for the maternal odor in female pups compared with nonhandled (NH) and the single-handled (SH) ones, while in RH males the preference was not different than NH and SH groups. In both male and female pups, RH decreased NA activity in the OB, but 5-HT activity increased only in males. Since preference for the maternal odor involves the synergic action of NA and 5-HT in the OB, the maintenance of the behavior in RH males could be related to the increased 5-HT activity, in spite of reduction in the NA activity in the OB. RH did not alter CREB phosphorylation in the OB of both male and females compared with NH pups. The repeated handling procedure can affect the behavior of rat pups in response to the maternal odor and biochemical parameters related to the olfactory learning mechanism. Sex differences were already detected in 7-day-old pups. Although the responsiveness of the hypothalamic-pituitary-adrenal axis to stressors is reduced in the neonatal period, environmental interventions may impact behavioral and biochemical mechanisms relevant to the animal at that early age.

  13. 白芍提取物对嗅球损毁抑郁模型大鼠行为学及下丘脑-垂体-肾上腺轴的影响%Influences of Extract of Peony Radix Alba on Behavior and Hypothalamic-pituitary-adrenocortical Axis in Depressive Rats Model with Damaged Olfactory Bulb

    Institute of Scientific and Technical Information of China (English)

    王景霞; 张建军; 苗春平; 刘妍; 林清; 陈振振

    2011-01-01

    Objective: To investigate the influences of extract from Peony Radix Alba on the behavioral and hypothalamic-pituitary-adrenocortical (HPA) axis changes in rats with damaged olfactory bulb (DOB). Method: The tests of open-field and step-down passive avoidance were used to observe the behaviors of rats.Radioimmunoassay (RIA) was used to analyze the level of corticotropin releasing hormone (CRH) in hypothalamus, adrenocorticotropic hormone (ACTH) in pituitary gland and cortisol (CORT) in serum of rats with DOB. Result: The rats had a characteristic hyperactivity in the test of "open-field" and learning deficits in stepdown passive avoidance ( P < 0. 05 ), and their levels of CRH, ACTH and CORT increased significantly ( P < 0. 05). The extract of Peony Radix Alba at the dose of 70,35 mg·kg-1 corrected the behavioral changes (P < 0. 05 ) and decreased the levels of CRH, ACTH and CORT ( P < 0. 05). Conclusion: The extract of Peony Radix Alba can correct behavioral changes in rats with DOB, and its regulating effect on HPA axis is one of the mechanisms for treating depression.%目的:研究白芍提取物对嗅球损毁抑郁模型大鼠行为学及下丘脑一垂体.肾上腺(HPA)轴的影响.方法:将嗅球损毁大鼠随机分为对照组、模型组、阳性药氟西汀2.5 mg·kg-1组以及白芍提取物70,35,17.5 mg·kg-1组,采用敞箱法、跳台法观察嗅球损毁大鼠的行为变化,间时用放免法分析白芍提取物对嗅球损毁大鼠下丘脑促肾上腺皮质激素释放素(CRH)、垂体促肾上腺皮质激素(ACTH)和血清皮质酮(CORT)含量的影响.结果:大鼠嗅球损毁后敞箱行为出现明显变化,水平运动和垂直运动显著增加,白芍提取物中、高剂量组可显著降低大鼠水平运动和垂直运动的得分;跳台试验中,造模后大鼠训练期和测试期的错误次数显著增加,自芍提取物中、高剂量组能显著降低嗅球损毁大鼠训练期和测试期的触电次数;嗅球损毁大

  14. A comparison between the human sense of smell and neural activity in the olfactory bulb of rats.

    Science.gov (United States)

    Soh, Zu; Saito, Maki; Kurita, Yuichi; Takiguchi, Noboru; Ohtake, Hisao; Tsuji, Toshio

    2014-02-01

    Generally, odor qualities are evaluated via sensory tests in which predefined criteria are assessed by panelists and stochastically analyzed to reduce human inconsistencies. Because this method requires multiple, well-trained human subjects, a more convenient approach is required to enable predictions of odor qualities. In this article, we propose an approach involving linking internal states of the olfactory system with perceptual characteristics. In the study, the glomerular responses of rats were taken to represent internal olfactory system states. Similarities between the glomerular responses of rats were quantified by correlations between glomerular activity patterns, overlap rate of strongly activated part across glomerular activity patterns, and the similarity between histograms of the strength of activity. These indices were then compared with perceptual similarities measured from human subjects in sensory tests. The results of experiments involving 22 odorants showed medium strength correlations between each index and perceptual similarity. In addition, when the 3 indices were combined using their Euclidean distance, we observed middle to high correlations (r = 0.65-0.79) to human perceptual similarity. We also report the results of our use of a machine learning technique to classify the odorants into a similar and dissimilar category. Although the correct rate of classification varied from 33.3% to 92.9%, these results support the feasibility of linking the glomerular responses of rats to human perception.

  15. Brain-derived neurotrophic factor levels influence the balance of migration and differentiation of subventricular zone cells, but not guidance to the olfactory bulb.

    Science.gov (United States)

    Petridis, Athanasios K; El Maarouf, Abderrahman

    2011-02-01

    New progenitor cells in the subventricular zone (SVZ) migrate rostrally and differentiate into interneurons in the olfactory bulb (OB) throughout life. Brain-derived neurotrophic factor (BDNF) may influence the normal progression of this migration. In the present study, mouse SVZ explant cultures were used to investigate how BDNF modulates the behavior of these migrating progenitors. Concentrations of BDNF in the physiological range (e.g. 1ng/mL) stimulated migration, whereas doses of 10 ng/mL or higher induced SVZ cell differentiation and reduced migration. Pharmacological inhibition of the mitogen-activated protein kinase (MAPK) pathway blocked the BDNF-induced differentiation of SVZ progenitors, indicating that differentiation of SVZ progenitors in response to high-dose BDNF is initiated through MAPK. Physiological concentrations of BDNF, like the presence of polysialic acid in the tissue, stimulated migration of cells from the explant without affecting the speed at which this occurs. Interestingly, in vivo immunohistochemical and molecular analysis showed similar levels of BDNF in both the SVZ and OB; that is, there was no positive gradient attracting SVZ cells towards the OB. Our data show that SVZ cells respond differently to different concentrations of BDNF.

  16. 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.

  17. Effect of rosebud extracts on piriform cortical neuronal damage and repair in olfactory bulb damaged rats and its mechanism%玫瑰花蕾萃取物对嗅球毁损大鼠梨形皮质神经元损伤修复的影响及机制

    Institute of Scientific and Technical Information of China (English)

    卞林翠; 王敏; 贺利敏; 徐金勇; 李光武

    2016-01-01

    目的:观察玫瑰花蕾萃取物对嗅球毁损大鼠梨形皮质神经元损伤修复的影响,探讨其作用机制。方法将60只成年健康雄性SD大鼠随机分为对照组(10只)、模型组(40只)及玫瑰花蕾组(10只)。对照组不做任何处理。模型组及玫瑰花蕾组采用探针破坏嗅球。嗅球毁损后1天,玫瑰花蕾组行玫瑰花蕾萃取物吸嗅,每次持续吸嗅1 h、2次/d,连续14天。分别取对照组、模型组嗅球毁损后24 h、72 h、7 d、14 d(每个时间10只)及玫瑰花蕾组吸嗅14天后脑组织,常规切片,采用尼氏染色法检测各组梨形皮质神经元损伤修复情况,采用免疫组化法检测梨形皮质谷氨酸(Glu)、γ-氨基丁酸(GABA)表达。结果对照组梨形皮质神经元尼式小体灰度值为87.32±3.14,模型组毁损24 h、72 h、7 d、14 d时灰度值分别为101.76±4.52、110.76±2.78、98.35±2.69、94.26±3.01,玫瑰花蕾组为88.47±4.33;模型组毁损72 h时尼式小体灰度值大于对照组和玫瑰花蕾组(P均<0.05)。与对照组比较,模型组毁损72 h、7 d时梨形皮质Glu表达减少、GABA表达增加;与模型组毁损72 h、7 d 比较,玫瑰花蕾组Glu表达增加、GABA表达减少;两组比较P均<0.05。结论玫瑰花蕾萃取物吸嗅对嗅球毁损大鼠梨形皮质神经元损伤修复具有促进作用,抑制Glu释放、促进GABA释放可能是其作用机制。%Objective To investigate the effect of rosebud extracts on piriform cortical neuronal damage and repair in olfactory bulb damaged rats and its mechanism.Methods Healthy adult male SD rats were randomly divided into three groups, namely the control group (n=10), model group (n=40) and rosebud group (n=10).Rats in the control group were not treated.Using probes agitation to damage the olfactory bulb of rats in the model group and rosebud group.One day after the damage of the olfactory

  18. 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.

  19. Isolation, culture and purification of offactory ensheathing cells from human fetal olfactory mucosa and from human fetal offactory bulb%人胚嗅球嗅鞘细胞及人胚鼻粘膜嗅鞘细胞的分离培养与纯化

    Institute of Scientific and Technical Information of China (English)

    郑遵成; 陶宗玉; 魏开斌; 张文正; 任玉水

    2012-01-01

    [目的]采用差速贴壁法及免疫组化对人胚嗅粘膜OECs及人胚嗅球OECs进行体外纯化培养,探讨建立嗅粘膜OECs及嗅球OECs体外培养的方法.[方法]对差速贴壁后的人胚嗅粘膜OECs及嗅球OECs分别交替应用含13%胎牛血清DMEM - F12培养基进行原代培养.观察嗅鞘细胞的形态学变化,采用p75NTR和GFAP免疫细胞化学染色进行鉴定和纯度检测.[结果]人胚嗅粘膜及人胚嗅球均可培养出嗅鞘细胞,嗅粘膜嗅鞘细胞形态多呈双极、三极,伴有细长的突起.p75NTR和GFAP染色均呈阳性反应,体外培养时人胚嗅球嗅鞘细胞纯度比人胚嗅粘膜嗅鞘细胞高.[结论]差速贴壁法可以分离培养出人胚嗅粘膜嗅鞘细胞及人胚嗅球嗅鞘细胞.%[Objective]To investigate differential adhesion method and immunohistochemistry in human embryo and human embryonic olfactory mucosa olfactory mucosal OECs OECs purified in vitro culture,explore the establishment of olfactory mucosa and olfactory bulb OECs OECs in vitro methods. [ Method] The differential adhesion of human fetal olfactory mucosa after olfactory bulb OECs and OECs were alternatively contained DMEM - F12 13% FBS medium in primary culture. The morphological changes of olfactory ensheathing cells were observed,p75NTR and GFAP immunocytochemistry for identification and purity testing was used. [Result] The human embryo and human embryonic olfactory mucosa olfactory bulb could be cultivated olfactory ensheathing cells,olfactory mucosa olfactory ensheathing cells form mostly bipolar,tripolar,with slender processes. p75NTR and GFAP staining were positive reaction. In vitro the purity of human fetal olfactory ensheathing cells cultured from human fetal olfactory ensheathing cells was higher than from olfactory mucosa. [ Conclusion ] The differential adhesion method can be isolated and cultured human embryonic cells and human fetal olfactory mucosa olfactory ensheathing cells, olfactory bulb.

  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. Olfactory ensheathing cell tumor

    Directory of Open Access Journals (Sweden)

    Ippili Kaushal

    2009-01-01

    Full Text Available Olfactory ensheathing cells (OECs are found in the olfactory bulb and olfactory nasal mucosa. They resemble Schwann cells on light and electron microscopy, however, immunohistochemical staining can distinguish between the two. There are less than 30 cases of olfactory groove schwannomas reported in the literature while there is only one reported case of OEC tumor. We report an OEC tumor in a 42-year-old male and discuss the pathology and origin of this rare tumor.

  2. Histogenesis of olfactory bulb and rostral migration stream in mice%小鼠嗅球以及吻侧迁移流的发生

    Institute of Scientific and Technical Information of China (English)

    高文静; 王志新; 徐高磊; 邓锦波; 高晓群

    2012-01-01

    目的:探讨嗅球结构和吻侧迁移流(RMS)的发生及其中神经干细胞的变化趋势.方法:利用H-E染色、Nissl染色标记嗅球形态结构,BrdU免疫荧光技术观察吻侧迁移流中增殖的神经干细胞.结果:嗅球组织结构的发生:胚胎期,嗅球各层的结构轮廓尚未发育完全;生后3d时,各层结构虽然发育完善,但层与层之间的交界处模糊不清,生后5d时,整个嗅球结构发育已经完善,也就意味着嗅觉系统发育成熟.迁移流的发生:胚胎初期,侧脑室是一个很大的空腔,管腔膜上布满了增殖的神经于细胞,脑室下区延伸入中空的嗅球中,之后管腔闭合,形成了原始的吻侧迁移流;出生时,吻侧迁移流中的细胞密度达到最大值,之后逐渐降低,直至消失.结论:嗅球片层化结构是从无到有,从不成熟到成熟的过程.吻侧迁移流的发生是侧脑室腔的闭合和室管下层上神经干细胞遗留的痕迹.%Objective:To discuss the structure of the olfactory bulb (OB), the occurrence of the rostral migration streams (RMS) and the change trend of neural stem cells in RMS. Methods: The histological structure of the OB was marked by the methods of HE staining and Nissl staining. Using bromodeoxyuridine (BrdU)-immunofluorescence to observe the proliferation of neural stem cells in RMS. Results: (1)In the embryonic period, the outline of the structure of the OB layers was not fully developed yet. On the third day after birth the structure developed well, but the junctions between layers were blurred. In P5, the development of the entire olfactory bulb was improved. (2)In the early embryo, the lateral ventricle was a large cavity. The lumen membrance was full of the proliferation of neural stem cells. The subventricular zone extended into the hollow of OB, and then closed the lumen, forming the original rostral migration stream. In P0, the cell density in RMS reached its maximum value, then gradually reduced until it

  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. A neural network model for olfactory glomerular activity prediction

    Science.gov (United States)

    Soh, Zu; Tsuji, Toshio; Takiguchi, Noboru; Ohtake, Hisao

    2012-12-01

    Recently, the importance of odors and methods for their evaluation have seen increased emphasis, especially in the fragrance and food industries. Although odors can be characterized by their odorant components, their chemical information cannot be directly related to the flavors we perceive. Biological research has revealed that neuronal activity related to glomeruli (which form part of the olfactory system) is closely connected to odor qualities. Here we report on a neural network model of the olfactory system that can predict glomerular activity from odorant molecule structures. We also report on the learning and prediction ability of the proposed model.

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

    Directory of Open Access Journals (Sweden)

    Hany E S Marei

    Full Text Available The 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, however effective delivery of NGF into the CNS parenchyma is still challenging due mainly to its limited ability to cross the blood-brain barrier, and intolerable side effects if administered into the brain ventricular system. An effective method to ensure delivery of NGF into the parenchyma of CNS is the genetic modification of NSC to overexpress NGF gene. Overexpression of NGF in adult human OBNSC is expected to alter their proliferation and differentiation nature, and thus might enhance their therapeutic potential. In this study, we genetically modified adult human OBNS/PC to overexpress human NGF (hNGF and green fluorescent protein (GFP genes to provide insight about the effects of hNGF and GFP genes overexpression in adult human OBNS/PC on their in vitro multipotentiality using DNA microarray, immunophenotyping, and Western blot (WB protocols. Our analysis revealed that OBNS/PC-GFP and OBNS/PC-GFP-hNGF differentiation is a multifaceted process involving changes in major biological processes as reflected in alteration of the gene expression levels of crucial markers such as cell cycle and survival markers, stemness markers, and differentiation markers. The differentiation of both cell classes was also associated with modulations of key signaling pathways such MAPK signaling pathway, ErbB signaling pathway, and neuroactive ligand-receptor interaction pathway for OBNS/PC-GFP, and axon guidance, calcium channel, voltage-dependent, gamma subunit 7 for OBNS/PC-GFP-hNGF as revealed by GO and KEGG. Differentiated OBNS/PC-GFP-hNGF displayed extensively branched cytoplasmic processes, a significant faster growth rate and up modulated the expression of oligodendroglia

  6. A neural network model of general olfactory coding in the insect antennal lobe.

    Science.gov (United States)

    Getz, W M; Lutz, A

    1999-08-01

    A central problem in olfaction is understanding how the quality of olfactory stimuli is encoded in the insect antennal lobe (or in the analogously structured vertebrate olfactory bulb) for perceptual processing in the mushroom bodies of the insect protocerebrum (or in the vertebrate olfactory cortex). In the study reported here, a relatively simple neural network model, inspired by our current knowledge of the insect antennal lobes, is used to investigate how each of several features and elements of the network, such as synapse strengths, feedback circuits and the steepness of neural activation functions, influences the formation of an olfactory code in neurons that project from the antennal lobes to the mushroom bodies (or from mitral cells to olfactory cortex). An optimal code in these projection neurons (PNs) should minimize potential errors by the mushroom bodies in misidentifying the quality of an odor across a range of concentrations while maximizing the ability of the mushroom bodies to resolve odors of different quality. Simulation studies demonstrate that the network is able to produce codes independent or virtually independent of concentration over a given range. The extent of this range is moderately dependent on a parameter that characterizes how long it takes for the voltage in an activated neuron to decay back to its resting potential, strongly dependent on the strength of excitatory feedback by the PNs onto antennal lobe intrinsic neurons (INs), and overwhelmingly dependent on the slope of the activation function that transforms the voltage of depolarized neurons into the rate at which spikes are produced. Although the code in the PNs is degraded by large variations in the concentration of odor stimuli, good performance levels are maintained when the complexity of stimuli, as measured by the number of component odorants, is doubled. When excitatory feedback from the PNs to the INs is strong, the activity in the PNs undergoes transitions from initial

  7. 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…

  8. Sendai Virus Induces Persistent Olfactory Dysfunction in a Murine Model of PVOD via Effects on Apoptosis, Cell Proliferation, and Response to Odorants.

    Directory of Open Access Journals (Sweden)

    Jun Tian

    Full Text Available Viral infection is a common cause of olfactory dysfunction. The complexities of studying post-viral olfactory loss in humans have impaired further progress in understanding the underlying mechanism. Recently, evidence from clinical studies has implicated Parainfluenza virus 3 as a causal agent. An animal model of post viral olfactory disorders (PVOD would allow better understanding of disease pathogenesis and represent a major advance in the field.To develop a mouse model of PVOD by evaluating the effects of Sendai virus (SeV, the murine counterpart of Parainfluenza virus, on olfactory function and regenerative ability of the olfactory epithelium.C57BL/6 mice (6-8 months old were inoculated intranasally with SeV or ultraviolet (UV-inactivated virus (UV-SeV. On days 3, 10, 15, 30 and 60 post-infection, olfactory epithelium was harvested and analyzed by histopathology and immunohistochemical detection of S-phase nuclei. We also measured apoptosis by TUNEL assay and viral load by real-time PCR. The buried food test (BFT was used to measure olfactory function of mice at day 60. In parallel, cultured murine olfactory sensory neurons (OSNs infected with SeV or UV-SeV were tested for odorant-mixture response by measuring changes in intracellular calcium concentrations indicated by fura-4 AM assay.Mice infected with SeV suffered from olfactory dysfunction, peaking on day 15, with no loss observed with UV-SeV. At 60 days, four out of 12 mice infected with SeV still had not recovered, with continued normal function in controls. Viral copies of SeV persisted in both the olfactory epithelium (OE and the olfactory bulb (OB for at least 60 days. At day 10 and after, both unit length labeling index (ULLI of apoptosis and ULLI of proliferation in the SeV group was markedly less than the UV-SeV group. In primary cultured OSNs infected by SeV, the percentage of cells responding to mixed odors was markedly lower in the SeV group compared to UV-SeV (P = 0.007.We

  9. 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.

  10. 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.

  11. Olfactory system and demyelination.

    Science.gov (United States)

    Garcia-Gonzalez, D; Murcia-Belmonte, V; Clemente, D; De Castro, F

    2013-09-01

    Within the central nervous system, the olfactory system represents one of the most exciting scenarios since it presents relevant examples of long-life sustained neurogenesis and continuous axonal outgrowth from the olfactory epithelium with the subsequent plasticity phenomena in the olfactory bulb. The olfactory nerve is composed of nonmyelinated axons with interesting ontogenetic interpretations. However, the centripetal projections from the olfactory bulb are myelinated axons which project to more caudal areas along the lateral olfactory tract. In consequence, demyelination has not been considered as a possible cause of the olfactory symptoms in those diseases in which this sense is impaired. One prototypical example of an olfactory disease is Kallmann syndrome, in which different mutations give rise to combined anosmia and hypogonadotropic hypogonadism, together with different satellite symptoms. Anosmin-1 is the extracellular matrix glycoprotein altered in the X-linked form of this disease, which participates in cell adhesion and migration, and axonal outgrowth in the olfactory system and in other regions of the central nervous system. Recently, we have described a new patho-physiological role of this protein in the absence of spontaneous remyelination in multiple sclerosis. In the present review, we hypothesize about how both main and satellite neurological symptoms of Kallmann syndrome may be explained by alterations in the myelination. We revisit the relationship between the olfactory system and myelin highlighting that minor histological changes should not be forgotten as putative causes of olfactory malfunction.

  12. 电生理法对豚鼠副嗅球功能分区的显示%Functional subdivisions of the guinea pig accessory olfactory bulb revealed by electrophysiology

    Institute of Scientific and Technical Information of China (English)

    余青松; 须贝外喜夫

    2001-01-01

    目的:探讨豚鼠副嗅球(AOB)是否存在多个功能分区。方法:在豚鼠副嗅球矢状位切片上,将双钨电极插入副嗅球前部或后部的犁鼻神经纤维层(VNL),以单个方波刺激传入神经纤维,用玻璃微电极记录AOB前部或后部外橄状层(EPL)细胞外场电位。结果:电刺激VNL,可在EPL记录到典型的衰减性场电位,且后EPL记录到的场电位的持续时间较前部分明显延长。刺激前VNL仅在前EPL记录到场电位,而刺激后VNL只在后EPL记录到场电位。结论:豚鼠副嗅球可分为前后两个亚区,两区存在解剖学上的差异,说明在犁鼻系统中至少存在两个不同的传入-传出通路。%Objective:To elucidate possible functional subdivisions in the guinea pig accessory olfactory bulb.Method:The guinea pig accessory olfactory bulbs were cut in sagittal slice.Bipolar tungsten electrodes were inserted into anterior or posterior vomeronasal nerve layers and single square-pulses were delivered through the eletrodes to activate afferent fibres.Glass microelectrodes were used to record extracellular field potentials of anterior or posterior external plexiform layers.Result:A single shook of the VNL provoked a characteristic damped oscillatory field potential and the oscillation in the pAOB was more distinct in wave form and longer in duration than those in the aAOB.The stimulation of anterior VNL elicited field potentials exelusively in the anterior region of EPL,whereas shocks to the posterior VNL provoked oscillatory responses only within the posterior EPL.Conclusion:The accessory olfactory bulb in the guinea-pig is distinctly segregated into the anterior and posterior subdivisions and an anatomical boundary exists in both regions.The results suggested that there are at least two different input-output pathways in vomeronasal systems.

  13. Bulb Miser

    Science.gov (United States)

    1978-01-01

    The Bulb-Miser was developed during NASA's Apollo program to protect the Saturn launch vehicle from electrical current surge. It is now being produced for the commercial market by Bulb-Miser, Inc., Houston, Texas. Technically known as a "temperature compensating thermistor," the Bulb-Miser is a simple, inexpensive device which looks like a washer about the size of a quarter. It is slipped between bulb and socket and can be used with any incandescent bulb that screws into a standard socket. In addition to delaying burnout, the Bulb-Miser also offers some reduction of electrical energy. But the economy of the device goes beyond energy use or bulb cost; to big users of bulbs, it makes possible substantially lower maintenance labor costs. One field test involving an apartment complex showed that it took two men 30 man hours monthly to replace light bulbs; after Bulb-Miser installation only nine man hours a month were needed. Bulb-Misers are used not only in private homes but also by hospitals, schools, hotels and motels, restaurants, banks and firms providing contract maintenance for large outdoor electric signs. The broadest use is in industrial facilities; the list of big companies which have purchased the Bulb-Miser reads like a Who's Who of American industry.

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

    Directory of Open Access Journals (Sweden)

    Bernhard A. Kaplan

    2014-02-01

    Full Text Available 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 to use 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/tuftedcells 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 likewiseorganized 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.

  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.

  16. Detecting Gustatory–Olfactory Flavor Mixtures: Models of Probability Summation

    Science.gov (United States)

    Veldhuizen, Maria G.; Shepard, Timothy G.; Shavit, Adam Y.

    2012-01-01

    Odorants and flavorants typically contain many components. It is generally easier to detect multicomponent stimuli than to detect a single component, through either neural integration or probability summation (PS) (or both). PS assumes that the sensory effects of 2 (or more) stimulus components (e.g., gustatory and olfactory components of a flavorant) are detected in statistically independent channels, that each channel makes a separate decision whether a component is detected, and that the behavioral response depends solely on the separate decisions. Models of PS traditionally assume high thresholds for detecting each component, noise being irrelevant. The core assumptions may be adapted, however, to signal-detection theory, where noise limits detection. The present article derives predictions of high-threshold and signal-detection models of independent-decision PS in detecting gustatory–olfactory flavorants, comparing predictions in yes/no and 2-alternative forced-choice tasks using blocked and intermixed stimulus designs. The models also extend to measures of response times to suprathreshold flavorants. Predictions derived from high-threshold and signal-detection models differ markedly. Available empirical evidence on gustatory–olfactory flavor detection suggests that neither the high-threshold nor the signal-detection versions of PS can readily account for the results, which likely reflect neural integration in the flavor system. PMID:22075720

  17. A Robust Feedforward Model of the Olfactory System

    Science.gov (United States)

    Zhang, Yilun; Sharpee, Tatyana

    Most natural odors have sparse molecular composition. This makes the principles of compressing 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 proposed that signal reconstruction could take place as a result of a low dimensional dynamical system converging to one of its attractor states. The dynamical aspects of optimization, however, would slow 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 Kenyon cells, which in the model corresponds to reconstruction. We show that provided this specific relationship holds true, the reconstruction will be both fast and robust to noise, and in particular to failure of glomeruli. The predicted connectivity rate from glomeruli to the Kenyon cells can be tested experimentally. This research was supported by James S. McDonnell Foundation, NSF CAREER award IIS-1254123, NSF Ideas Lab Collaborative Research IOS 1556388.

  18. Modeling and simulation of residual stresses during glass bulb pressing process

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The residual stresses accumulated in the forming process have great effects on the product quality of the glass bulb. Based on the characteristics analysis of glass bulb forming, a mathematical model has been established for calculating residual stresses of glass pressing process. The material is assumed as thermorheologi-cally simple thermoviscoelastic material, and the flow-induced stress is neglected. The consequences of equilibrium and compatibility equations are discussed in detail, and the boundary conditions are specified for various stages of the forming process. The numerical solution is based on the theory of thin layers, combined with finite difference method in the time and layer difference in the thickness di-rection. The presented model and solution method could easily be extended to general pressing process of glass, and applied to problems relative to glass pressing, providing extensive reference values.

  19. Transient and sustained afterdepolarizations in accessory olfactory bulb mitral cells are mediated by distinct mechanisms that are differentially regulated by neuromodulators

    NARCIS (Netherlands)

    G. Shpak (Guy); A. Zylbertal (Asaph); S. Wagner (Shlomo)

    2015-01-01

    textabstractSocial interactions between mammalian conspecifics rely heavily on molecular communication via the main and accessory olfactory systems. These two chemosensory systems show high similarity in the organization of information flow along their early stages: social chemical cues are detected

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

    Science.gov (United States)

    R, Fraser; D, Vallée; Y, Jean; C, Deschênes

    2014-03-01

    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.

  1. 2,6-二异丙基苯酚逆转嗅球切除抑郁模型大鼠电休克后的Tau蛋白过度磷酸化和认知障碍%2,6-Diisopropylphenol Protects Against The Impairment of Learning-memory and Reduces The Hyperphosphorylation of Protein Tau Induced by Electroconvulsive Shock in The Depression Model Rats Whose Olfactory Bulbs Were Removed

    Institute of Scientific and Technical Information of China (English)

    刘超; 闵苏; 魏柯; 刘东; 董军; 罗洁; 刘小滨

    2012-01-01

    Protein Tau is a very unequal phosphoric microtubule associated protein, which affect the transport of substances in the axons of the neurons, whose phosphorylation is one of the key methods to regulate neuronal function. The hyperphosphorylation of protein Tau can damage the learning and memory of rats. The impairment of learning-memory induced by electroconvulsive shock in depressed rats is relevant to the function failure of glutamic acid signal system. The phosphorylation of protein Tau can be up-regulated by the individual stress level through the excitatory neurotransmission system. The mechanisms of 2, 6-diisopropylphenol effect on the central nerve system relate to inhibiting the release of glutamic acid and the activity of NMDAR. And the 2, 6-diisopropylphenol can protects against the impairment of learning-memory induced by electroconvulsive shock in depressed rats though inhibiting the excitotoxicty of glutamate. The rise of glutamic acid which induced by electroconvulsive shock in depressed rats can lead to the impairment of learning-memory through up-regulating the hyperphosphorylation of protein Tau? The 2, 6-diisopropylphenol can protect against this process? This study explore the reversion of the 2, 6-diisopropylphenol against the impairment of learning-memory and the hyperphosphorylation of protein Tau induced by electroconvulsive shock in depressed rats, in order to provide experimental evidence for neuropsychological mechanisms on improving learning and memory and the clinical intervention treatment. According to the design of factorial analysis, two intervention factors were set up: the electroconvulsive shock (two levels: no disposition; a course of electroconvulsive shock) and the 2, 6-diisopropylphenol (two levels: 5 ml Saline was injected peritoneally; 5 ml 2, 6-diisopropylphenol was injected peritoneally by dosage of 100 mg/kg). Thirty-two adult depression model rats whose olfactory bulbs were removed were randomly divided into four

  2. Playing with a bulb lamp: RTL measurements and modelling

    Science.gov (United States)

    Torzo, G.; D'Anna, M.; Pecori, B.

    2016-09-01

    The electric, thermal and optical behaviour of an incandescent lamp was studied by a real time laboratory (RTL) apparatus, using two voltage probes and a light probe. The software STELLA was used to model the phenomena and to analyse the transient behaviour in absence of thermal equilibrium. We show how the Joule-heating effect explains the non-linear current/voltage relation and how the filament thermal capacity affects the phase lag of light peaks with respect to input power peaks.

  3. 基于微电极阵列的嗅球细胞网络传感器的研究%Study on Olfactory Bulb Cell Network Biosensor Based on Microelectrode Array

    Institute of Scientific and Technical Information of China (English)

    陈庆梅; 肖丽丹; 李蓉; 张威; 刘清君; 王平

    2011-01-01

    嗅球(OB)是嗅觉系统的第一中转站,在嗅觉信息的识别和处理中具有重要的作用.嗅球中具有多种类型的神经元,分别具有不同的生理特点和功能.本研究利用细胞培养技术,将嗅球神经元与微电极阵列(MEA)芯片耦合,构建一种细胞网络传感器,用于对多点的嗅球神经元电活动进行同步观察与分析.结果显示,MEA上培养的嗅球细胞生长良好,能够检测多个通道的嗅球神经元的自发电位以及谷氨酸作用下的诱发响应.研究表明,该嗅球细胞网络传感器能够实现信号的多通道同步检测及有效分辨神经元的自发信号和诱发响应,并且能够很好地捕捉不同通道神经元响应的特点.该研究对于进一步分析嗅觉信息在嗅球内的传导和编码具有重要的意义.%Olfactory bulb ( OB ) is the first relay site of the olfactory system, which is important for identifying and processing the olfactory information. There are multi-type neurons in OB, respectively with different physiological characteristics and functions. In the present study, OB neurons were coupled onto MEA chip by cell culture technique to develop a cell network-based biosensor, which was used to synchronously observe and analyze the electrical activities of OB neurons with multi-sites. Experiment results showed that OB cells grew well on MEA, and multi-channel spontaneous signals can be measured. In addition, this biosensor can detect the induced spike potentials and oscillation signals by the OB neurons under the action of glutamic acid ( Clu). All results suggest that OB cell network-based biosensor can realize multi-channel synchronous measurement and effectively differentiate the spontaneous signals from the induced responses, and can also catch the characteristics of neuronal responses of different channels commendably. This research is significant for further investigating the conduction and coding functions of olfactory information in the OB.

  4. 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.

  5. [Comparative analysis of the monopodial and sympodial models of bulb branching in Galanthus L].

    Science.gov (United States)

    Chub, V V; Kozhevnikova, A D

    2000-01-01

    We have examined sympodial and monopodial models of bulb branching in Galanthus. The issue of the position of the reduced prophyll is discussed. We proposed a method of formal interpretation: parts of the plant were positioned on diagrams; several variants of axial schemes were matched to each diagram; the schemes were divided into two classes, monopodial and sympodial ones, and stability of each class was estimated. In order to decide about the model of Galanthus bulb branching, we have examined plants with additional inflorescences and plants with additional leaf series. We have shown that the sympodial model predicts the presence of the reduced prophyll at the base of the innovation bud in all studied cases. Consecutive stages of prophyll reduction (prophyll of the innovation bud) can be followed in Amaryllidaceae in the following sequence: Zephyranthes, a well-developed large prophyll with green lamina; Vallota, a developed prophyll with reduced green lamina; Haemanthus, a thin chaffy short-living prophyll. At the end of this sequence is Galanthus with completely reduced prophyll at the innovation bud.

  6. 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

  7. Preliminary investigation of flow dynamics during the start-up of a bulb turbine model

    Science.gov (United States)

    Coulaud, M.; Fraser, R.; Lemay, J.; Duquesne, P.; Aeschlimann, V.; Deschênes, C.

    2016-11-01

    Nowadays, the electricity network undergoes more perturbations due to the market demand. Additionally, an increase of the production from alternative resources such as wind or solar also induces important variations on the grid. Hydraulic power plants are used to respond quickly to these variations to stabilize the network. Hydraulic turbines have to face more frequent start-up and stop sequences that might shorten significantly their life time. In this context, an experimental analysis of start-up sequences has been conducted on the bulb turbine model of the BulbT project at the Hydraulic Machines Laboratory (LAMH) of Laval University. Maintaining a constant head, guide vanes are opened from 0 ° to 30 °. Three guide vanes opening speed have been chosen from 5 °/s to 20 °/s. Several repetitions were done for each guide vanes opening speed. During these sequences, synchronous time resolved measurements have been performed. Pressure signals were recorded at the runner inlet and outlet and along the draft tube. Also, 25 pressure measurements and strain measurements were obtained on the runner blades. Time resolved particle image velocimetry were used to evaluate flowrate during start-up for some repetitions. Torque fluctuations at shaft were also monitored. This paper presents the experimental set-up and start-up conditions chosen to simulate a prototype start-up. Transient flowrate methodology is explained and validation measurements are detailed. The preliminary results of global performances and runner pressure measurements are presented.

  8. The progress of olfactory transduction and biomimetic olfactory-based biosensors

    Institute of Scientific and Technical Information of China (English)

    WU ChunSheng; WANG LiJiang; ZHOU Jun; ZHAO LuHang; WANG Ping

    2007-01-01

    Olfaction is a very important sensation for all animals. Recently great progress has been made in the research of olfactory transduction. Especially the novel finding of the gene superfamily encoding olfactory receptors has led to rapid advances in olfactory transduction. These advances also promoted the research of biomimetic olfactory-based biosensors and some obvious achievements have been obtained due to their potential commercial prospects and promising industrial applications. This paper briefly introduces the biological basis of olfaction, summarizes the progress of olfactory signal transduction in the olfactory neuron, the olfactory bulb and the olfactory cortex, outlines the latest developments and applications of biomimetic olfactory-based biosensors. Finally, the olfactory biosensor based on light addressable potentiometric sensor (LAPS) is addressed in detail based on our recent work and the research trends of olfactory biosensors in future are discussed.

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

    Science.gov (United States)

    Rodrigues, Lais S; Targa, Adriano D S; Noseda, Ana Carolina D; Aurich, Mariana F; Da Cunha, Cláudio; Lima, Marcelo M S

    2014-01-01

    Olfactory and rapid eye movement (REM) sleep deficits are commonly found in untreated subjects with a recent diagnosis of Parkinson's disease (PD). Additionally, different studies report declines in olfactory performance during a short period of sleep deprivation. Mechanisms underlying these clinical manifestations are poorly understood, and impairment of dopamine (DA) neurotransmission in the olfactory bulb and the nigrostriatal pathway may have important roles in olfaction and REM sleep disturbances. Therefore, we hypothesized that modulation of the dopaminergic D2 receptors in the olfactory bulb could provide a more comprehensive understanding of the olfactory deficits in PD and REM sleep deprivation (REMSD). We decided to investigate the olfactory, neurochemical, and histological alterations generated through the administration of piribedil (a selective D2 agonist) or raclopride (a selective D2 antagonist) within the glomerular layer of the olfactory bulb, in rats subjected to intranigral rotenone and REMSD. Our findings provide 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 nigrostriatal DA levels and olfactory discrimination index (DI) for the sham groups, indicating that increased DA levels in the substantia nigra pars compacta (SNpc) are associated with enhanced olfactory discrimination performance. Also, increased levels in bulbar and striatal DA were induced by piribedil in the rotenone control and rotenone REMSD groups, consistent with reductions in the DI. The present evidence reinforce the idea that DA produced by periglomerular neurons, particularly the bulbar dopaminergic D2 receptors, is an essential participant in olfactory discrimination processes, as the SNpc, and the striatum.

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

    Science.gov (United States)

    Rodrigues, Lais S.; Targa, Adriano D. S.; Noseda, Ana Carolina D.; Aurich, Mariana F.; Da Cunha, Cláudio; Lima, Marcelo M. S.

    2014-01-01

    Olfactory and rapid eye movement (REM) sleep deficits are commonly found in untreated subjects with a recent diagnosis of Parkinson’s disease (PD). Additionally, different studies report declines in olfactory performance during a short period of sleep deprivation. Mechanisms underlying these clinical manifestations are poorly understood, and impairment of dopamine (DA) neurotransmission in the olfactory bulb and the nigrostriatal pathway may have important roles in olfaction and REM sleep disturbances. Therefore, we hypothesized that modulation of the dopaminergic D2 receptors in the olfactory bulb could provide a more comprehensive understanding of the olfactory deficits in PD and REM sleep deprivation (REMSD). We decided to investigate the olfactory, neurochemical, and histological alterations generated through the administration of piribedil (a selective D2 agonist) or raclopride (a selective D2 antagonist) within the glomerular layer of the olfactory bulb, in rats subjected to intranigral rotenone and REMSD. Our findings provide 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 nigrostriatal DA levels and olfactory discrimination index (DI) for the sham groups, indicating that increased DA levels in the substantia nigra pars compacta (SNpc) are associated with enhanced olfactory discrimination performance. Also, increased levels in bulbar and striatal DA were induced by piribedil in the rotenone control and rotenone REMSD groups, consistent with reductions in the DI. The present evidence reinforce the idea that DA produced by periglomerular neurons, particularly the bulbar dopaminergic D2 receptors, is an essential participant in olfactory discrimination processes, as the SNpc, and the striatum. PMID:25520618

  11. Activity of the principal cells of the olfactory bulb promotes a structural dynamic on the distal dendrites of immature adult-born granule cells via activation of NMDA receptors.

    Science.gov (United States)

    Breton-Provencher, Vincent; Coté, Daniel; Saghatelyan, Armen

    2014-01-29

    The adult olfactory bulb is continuously supplied with neuronal precursors that differentiate into granule and periglomerular cells. Little is known about the structural dynamic of adult-born granule cells (GCs) at their different maturational stages, the mechanisms controlling the integration of new neurons into the pre-existing neuronal circuitry, or the role of principal cell activity in these processes. We used two-photon time-lapse imaging to reveal a high level of filopodia formation and retraction on the distal dendrites of adult-born GCs at their early maturational stages. This dynamic decreased as the adult-born interneurons matured. Filopodia formation/retraction on the dendrites of adult-born GCs at the early maturational stages depended on the activation of NMDA receptors (NMDARs). The stimulation of mitral cells using a pattern that mimics activity of these principal neurons to odor presentation promotes the NMDAR-dependent filopodia dynamic of adult-born GCs during their early but not late maturational stages. Moreover, NMDA iontophoresis was sufficient to induce the formation of new filopodia on the distal dendrites of immature adult-born GCs. The maturation of adult-born interneurons was accompanied by a progressive hyperpolarization of the membrane potential and an increased Mg(2+) block of NMDARs. Decreasing the extracellular Mg(2+) concentration led to filopodia formation on the dendrites of mature adult-born GCs following NMDA iontophoresis. Our findings reveal an increased structural dynamic of adult-born GCs during the early stages of their integration into the mouse bulbar circuitry and highlight a critical period during which the principal cells' activity influences filopodia formation/retraction on the dendrites of interneurons.

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

    Energy Technology Data Exchange (ETDEWEB)

    Duprez, Thierry P. [Department of Radiology and Medical Imaging, Universite catholique de Louvain, Cliniques Universitaires Saint-Luc, Avenue Hippocrate, 10, 1200-Brussels (Belgium)], E-mail: Thierry.Duprez@uclouvain.be; Rombaux, Philippe [Department of Otorhinolaryngology, Universite catholique de Louvain, Cliniques Universitaires Saint-Luc, Avenue Hippocrate, 10, 1200-Brussels (Belgium)], E-mail: Philippe.Rombaux@uclouvain.be

    2010-05-15

    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.

  13. Concise review: Patient-derived olfactory stem cells: new models for brain diseases.

    Science.gov (United States)

    Mackay-Sim, Alan

    2012-11-01

    Traditional models of brain diseases have had limited success in driving candidate drugs into successful clinical translation. This has resulted in large international pharmaceutical companies moving out of neuroscience research. Cells are not brains, obviously, but new patient-derived stem models have the potential to elucidate cell biological aspects of brain diseases that are not present in worm, fly, or rodent models, the work horses of disease investigations and drug discovery. Neural stem cells are present in the olfactory mucosa, the organ of smell in the nose. Patient-derived olfactory mucosa has demonstrated disease-associated differences in a variety of brain diseases and recently olfactory mucosa stem cells have been generated from patients with schizophrenia, Parkinson's disease, and familial dysautonomia. By comparison with cells from healthy controls, patient-derived olfactory mucosa stem cells show disease-specific alterations in gene expression and cell functions including: a shorter cell cycle and faster proliferation in schizophrenia, oxidative stress in Parkinson's disease, and altered cell migration in familial dysautonomia. Olfactory stem cell cultures thus reveal patient-control differences, even in complex genetic diseases such as schizophrenia and Parkinson's disease, indicating that multiple genes of small effect can converge on shared cell signaling pathways to present as a disease-specific cellular phenotype. Olfactory mucosa stem cells can be maintained in homogeneous cultures that allow robust and repeatable multiwell assays suitable for screening libraries of drug candidate molecules. Copyright © 2012 AlphaMed Press.

  14. Quasars Are Not Light-Bulbs: Testing Models of Quasar Lifetimes with the Observed Eddington Ratio Distribution

    CERN Document Server

    Hopkins, Philip F

    2008-01-01

    We use the observed distribution of Eddington ratios as a function of supermassive black hole (BH) mass to constrain models of AGN lifetimes and lightcurves. Given the observed AGN luminosity function, a model for AGN lifetimes (time above a given luminosity) translates directly to a predicted Eddington ratio distribution. Models for self-regulated BH growth, in which feedback produces a 'blowout' decay phase after some peak luminosity (shutting down accretion) make specific predictions for the lifetimes distinct from those expected if AGN are simply gas starved (without feedback) and very different from simple phenomenological 'light bulb' models. Present observations of the Eddington ratio distribution, spanning 5 decades in Eddington ratio, 3 in BH mass, and redshifts z=0-1, agree with the predictions of self-regulated models, and rule out 'light-bulb', pure exponential, and gas starvation models at high significance. We compare the Eddington ratio distributions at fixed BH mass and fixed luminosity (both ...

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

    Directory of Open Access Journals (Sweden)

    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.

  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. 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;…

  18. Efficiency prediction for a low head bulb turbine with SAS SST and zonal LES turbulence models

    Science.gov (United States)

    Jošt, D.; Škerlavaj, A.

    2014-03-01

    A comparison between results of numerical simulations and measurements for a 3-blade bulb turbine is presented in order to determine an appropriate numerical setup for accurate and reliable simulations of flow in low head turbines. Numerical analysis was done for three angles of runner blades at two values of head. For the smallest blade angle the efficiency was quite accurately predicted, but for the optimal and maximal blade angles steady state analysis entirely failed to predict the efficiency due to underestimated torque on the shaft and incorrect results in the draft tube. Transient simulation with SST did not give satisfactory results, but with SAS and zonal LES models the prediction of efficiency was significantly improved. From the results obtained by SAS and zonal LES the interdependence between turbulence models, vortex structures in the flow, values of eddy viscosity and flow energy losses in the draft tube can be seen. Also the effect of using the bounded central differential scheme instead of the high resolution scheme was evident. To test the effect of grid density, simulations were performed on four grids. While a difference between results obtained on the basic grid and on the fine grid was small, the results obtained on the coarse grids were not satisfactory.

  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.

    Directory of Open Access Journals (Sweden)

    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. The olfactory system as a puzzle: playing with its pieces.

    Science.gov (United States)

    Díaz, D; Gómez, C; Muñoz-Castañeda, R; Baltanás, F; Alonso, J R; Weruaga, E

    2013-09-01

    The mammalian olfactory bulb (OB) has all the features of a whole mammalian brain but in a more reduced space: neuronal lamination, sensory inputs, afferences, or efferences to other centers of the central nervous system, or a contribution of new neural elements. Therefore, it is widely considered as "a brain inside the brain." Although this rostral region has the same origin and general layering as the other cerebral cortices, some distinctive features make it very profitable in experimentation in neurobiology: the sensory inputs are driven directly on its surface, the main output can be accessed anatomically, and new elements appear in it throughout adult life. These three morphological characteristics have been manipulated to analyze further the response of the whole OB. The present review offers a general outlook into the consequences of such experimentation in the anatomy, connectivity and neurochemistry of the OB after (a) sensory deprivation, mainly by naris occlusion; (b) olfactory deinnervation by means of olfactory epithelium damage, olfactory nerve interruption, or even olfactory tract disruption; (c) the removal of the principal neurons of the OB; and (d) management of the arrival of newborn interneurons from the rostral migratory stream. These experiments were performed using surgical or chemical methods, but also by means of the analysis of genetic models, some of whose olfactory components are missing, colorless or mismatching within the wild-type scenario of odor processing.

  1. Anatomical specializations for enhanced olfactory sensitivity in kiwi, Apteryx mantelli.

    Science.gov (United States)

    Corfield, Jeremy R; Eisthen, Heather L; Iwaniuk, Andrew N; Parsons, Stuart

    2014-01-01

    The ability to function in a nocturnal and ground-dwelling niche requires a unique set of sensory specializations. The New Zealand kiwi has shifted away from vision, instead relying on auditory and tactile stimuli to function in its environment and locate prey. Behavioral evidence suggests that kiwi also rely on their sense of smell, using olfactory cues in foraging and possibly also in communication and social interactions. Anatomical studies appear to support these observations: the olfactory bulbs and tubercles have been suggested to be large in the kiwi relative to other birds, although the extent of this enlargement is poorly understood. In this study, we examine the size of the olfactory bulbs in kiwi and compare them with 55 other bird species, including emus, ostriches, rheas, tinamous, and 2 extinct species of moa (Dinornithiformes). We also examine the cytoarchitecture of the olfactory bulbs and olfactory epithelium to determine if any neural specializations beyond size are present that would increase olfactory acuity. Kiwi were a clear outlier in our analysis, with olfactory bulbs that are proportionately larger than those of any other bird in this study. Emus, close relatives of the kiwi, also had a relative enlargement of the olfactory bulbs, possibly supporting a phylogenetic link to well-developed olfaction. The olfactory bulbs in kiwi are almost in direct contact with the olfactory epithelium, which is indeed well developed and complex, with olfactory receptor cells occupying a large percentage of the epithelium. The anatomy of the kiwi olfactory system supports an enhancement for olfactory sensitivities, which is undoubtedly associated with their unique nocturnal niche.

  2. 1-甲基-4-苯基-1,2,3,6-四氢吡啶对食蟹猴嗅球多巴胺能神经元的影响%Impact on the dopaminergic neurons of olfactory bulb in cynomolgus monkeys damaged by MPTP

    Institute of Scientific and Technical Information of China (English)

    程炜; 任振华; 关云谦; 吴迪; 岳峰; 李光武

    2014-01-01

    Objective To explore the localization and expression of dopaminergic neurons in olfactory bulb of cynomolgus monkeys damaged by 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP).Methods Three adult cynomolgus monkeys were injected with MPTP to induce the damage of dopamine neurons ( MPTP group ) and three adult cynomolgus monkeys were as a control group .Immunohistochemical staining was performed to examine the localization and expression of dopaminergic neurons in the olfactory bulb in normal and MPTP group monkeys .The numbers of DA-positive and DARPP32-positive cells were counted and the average absorbance was measured in normal and MPTP group .Results DA and DARPP32 positive neurons were concentrated in the glomerular layer ( GL) of olfactory bulb.DA positive nerve fibers were distributed in the GL while DARPP 32 positive nerve fibers appeared in all layers , and most nerve fibers were in GL and external plexiform layers (EPL).After MPTP injury, compared with the normal control group , DA and DARPP32 positive neurons and nerve fibers decreased in MPTP group and DA neurons and nerve fibers decreased significantly . Conclusions DA neurons and nerve fibers are in the GL of cynomolgus monkey olfactory bulb .DA neurons and fibers are significantly reduced in the olfactory bulb of cynomolgus monkeys damaged by MPTP , which may be associated with the dysosmia in Parkinson ’ s disease .%目的:建立食蟹猴1-甲基-4-苯基-1,2,3,6-四氢吡啶(MPTP)帕金森病系统性模型,探讨嗅球中多巴胺(DA)及多巴胺/cAMP调节磷蛋白(DARPP32)的表达情况。方法3只成年健康食蟹猴,静脉注射MPTP,建立帕金森病系统性模型,取出嗅球,切片,免疫组织化学染色DA和DARPP32,摄片并观察DA和DARPP32在食蟹猴嗅球中的分布及表达情况,采用Image Pro-Plus软件,半定量分析模型组和正常组之间DA和DARPP32的表达差异。结果食蟹猴嗅球中DA和DARPP32神经元集

  3. 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…

  4. The olfactory glomerulus: a model for neuro-glio-vascular biology.

    Science.gov (United States)

    Shepherd, Gordon M; Charpak, Serge

    2008-06-26

    The cellular basis of brain imaging is emerging as a new frontier in current neuroscience. In this issue of Neuron, Petzold et al. analyze a model system, the olfactory glomerulus, to show how neurovascular coupling involves an elaborate dance between axon terminals, presynaptic and postsynaptic dendrites, glial cells, and the capillary network.

  5. Studies on the correlation with olfactory dysfunction in a transgenic mice model of Alzheimer's disease

    Science.gov (United States)

    Rasheed, Ameer; Lee, Ji Hye; Suh, Yoo-Hun; Moon, Cheil

    2013-05-01

    Alzheimer's disease (AD) is a progressively debilitating neurodegenerative disorder characterized by the presence of proteinaceous deposits in the brain. AD often results in olfactory dysfunction and impaired olfactory perceptual acuity may be a potential biomarker for early diagnosis of AD. Until recently, there is no Alzheimer's nanoscope or any other high-end microscope developed to be capable of seeing buried feature of AD clearly. Modern neuroimaging techniques are more effective only after the occurrence of cognitive impairment. Therefore, early detection of Alzheimer's disease is critical in developing effective treatment of AD. H and E (Haematoxyline and Eosin) staining is performed for examining gross morphological changes, while TUNEL (transferase (TdT)-mediated dUTP nick end labeling) staining for monitoring neuronal death in the olfactory epithelium (OE). Furthermore, immunohistochemistry and western blot are performed to examine β-amyloid protein expression. AD model animals were Tg2576 (transgenic mice that overexpress a mutated form of the Aβ precursor protein), and 6 month (before onset of AD symptoms) and 14 month (after onset of AD symptoms) old WT (wild type) and transgenic mice were compared in their olfactory system. We found that in OE of Tg2576 mice, thickness and total number of cells were decreased, while the numbers of TUNEL-positive neurons, caspase-3 activation were significantly increased compared with age-matched WT. Our results demonstrate that the olfactory system may get deteriorated before onset of AD symptoms. Our findings imply that an olfactory biopsy could be served as an early and relatively simple diagnostic tool for potential AD patients.

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

    Science.gov (United States)

    Yamaguchi, Masahiro; Manabe, Hiroyuki; Murata, Koshi; Mori, Kensaku

    2013-01-01

    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 circuits in the brain.

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

    Directory of Open Access Journals (Sweden)

    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

  8. 成年小鼠嗅球神经干细胞的培养和鉴定%In vitro culture and identification of neural stem cells derived from the olfactory bulb of adult mice

    Institute of Scientific and Technical Information of China (English)

    胡继良; 姜晓丹; 邹雨汐; 薛杉; 郭燕舞; 周德祥; 徐如祥

    2008-01-01

    目的 建立完善的成年小鼠嗅球神经千细胞分离培养和鉴定方法,探索新的成年神经干细胞种子来源. 方法 用无血清方法 分离培养成年小鼠嗅球来源的神经干细胞;用克隆培养、5-溴2-脱氧尿嘧啶核昔(BrdU)整合的方法 检验培养细胞的干细胞特性;用免疫荧光细胞化学的方法 检测BrdU、神经干细胞标记物巢蛋白(nestin)和SOX2、分化的细胞标记物Tuj1、胶质纤维酸性蛋白(GFAP)、04的表达. 结果 从成年小鼠嗅球能够分离、培养出具有自我更新、增殖能力的神经球.构成神经球的细胞呈nestin和SOX2阳性,它们分化后产生TuJ1阳性的神经元、GFAP阳性的星形胶质细胞、04阳性的少突胶质细胞. 结论 成年小鼠嗅球存在神经干细胞,其能够在体外进行培养、增殖、分化.是神经干细胞的新的种子来源.%Objecfive To establish a method for in vitro culture and identification of neural stem cells(NSCs)derived from the olfactory bulb(OB)of adult mice and test the possibility of the OB as a new source of seed cells of adult NSCs. Methads NSCs were isolated from the OB of adult mice and cultured in serum-free medium.Clonal culture and BrdU incorporation assay were performed to assess the self-renewal and proliferative activities of the NSCs.Fluorescence immunocytochemistry was carried out to examine the expression of the NSC markers nestin and SOX2,neuronal marker Tujl,astrocyte marker GFAP and oligodendroeyte marker 04. Results NSCs possessing self-renewal and proliferative capacities were obtained from the OB of adult mice,and the cells grew in the form of floating neurospheres in the medium.The neurospheres consisted of cells were positive for NSC markers nestin and SOX2,which Were able to differentiate into Tuj1-positive neurons,GFAP-positive astrocytes and 04-positive oligodendrocytes. Conclusion NSCs are present in the OB of adult mice,and the NSCs isolated from the OB can proliferate and

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

    Directory of Open Access Journals (Sweden)

    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

  10. 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.

  11. A subtype-specific critical period for neurogenesis in the postnatal development of mouse olfactory glomeruli.

    Directory of Open Access Journals (Sweden)

    Yasuko Kato

    Full Text Available Sensory input is essential for the normal development of sensory centers in the brain, such as the somatosensory, visual, auditory, and olfactory systems. Visual deprivation during a specific developmental stage, called the critical period, results in severe and irreversible functional impairments in the primary visual cortex. Olfactory deprivation in the early postnatal period also causes significant developmental defects in the olfactory bulb, the primary center for olfaction. Olfactory bulb interneurons are continuously generated from neural stem cells in the ventricular-subventricular zone, suggesting that the olfactory system has plasticity even in adulthood. Here, we investigated the effect of transient neonatal olfactory deprivation on the addition of interneurons to the glomerular layer of the adult mouse olfactory bulb. We found that the addition of one subtype of interneurons was persistently inhibited even after reopening the naris. BrdU pulse-chase experiments revealed that the neonatal olfactory deprivation predominantly affected an early phase in the maturation of this neuronal subtype in the olfactory bulb. Subjecting the mice to odor stimulation for 6 weeks after naris reopening resulted in significant recovery from the histological and functional defects caused by the olfactory deprivation. These results suggest that a subtype-specific critical period exists for olfactory bulb neurogenesis, but that this period is less strict and more plastic compared with the critical periods for other systems. This study provides new insights into the mechanisms of postnatal neurogenesis and a biological basis for the therapeutic effect of olfactory training.

  12. Immunohistochemical and histochemical characteristics of the olfactory system of the guppy, Poecilia reticulata (Teleostei, Poecilidae).

    Science.gov (United States)

    Bettini, Simone; Lazzari, Maurizio; Ciani, Franco; Franceschini, Valeria

    2009-10-01

    Olfaction in fish has been studied using preferentially macrosmatic species as models. In the present research, the labelling patterns of different neuronal markers and lectins were analyzed in the olfactory neurons and in their bulbar axonal endings in the guppy Poecilia reticulata, belonging to the group of microsmatic fish. We observed that calretinin immunostaining was confined to a population of olfactory receptor cells localized in the upper layers of the sensory mucosa, probably microvillous neurons innervating the lateral glomerular layer. Immunoreactivity for S100 proteins was mainly evident in crypt cells, but also in other olfactory cells belonging to subtypes projecting in distinct regions of the bulbs. Protein gene product 9.5 (PGP 9.5) was not detected in the olfactory system of the guppy. Lectin binding revealed the presence of N-acetylglucosamine and alpha-N-acetylgalactosamine residues in the glycoconjugates of numerous olfactory neurons ubiquitously distributed in the mucosa. The low number of sugar types detected suggested a reduced glycosidic variability that could be an index of restricted odorant discrimination, in concordance with guppy visual-based behaviors. Finally, we counted few crypt cells which were immunoreactive for S100 and calretinin. Crypt cells were more abundant in guppy females. This difference is in accordance with guppy gender-specific responses to pheromones. Cells immunoreactive to calretinin showed no evidence of ventral projections in the bulbs. We assumed the hypothesis that their odorant sensitivity is not strictly limited to pheromones or sexual signals in general.

  13. Shh-proteoglycan interactions regulate maturation of olfactory glomerular circuitry.

    Science.gov (United States)

    Persson, Laura; Witt, Rochelle M; Galligan, Meghan; Greer, Paul L; Eisner, Adriana; Pazyra-Murphy, Maria F; Datta, Sandeep R; Segal, Rosalind A

    2014-12-01

    The olfactory system relies on precise circuitry connecting olfactory sensory neurons (OSNs) and appropriate relay and processing neurons of the olfactory bulb (OB). In mammals, the exact correspondence between specific olfactory receptor types and individual glomeruli enables a spatially precise map of glomerular activation that corresponds to distinct odors. However, the mechanisms that govern the establishment and maintenance of the glomerular circuitry are largely unknown. Here we show that high levels of Sonic Hedgehog (Shh) signaling at multiple sites enable refinement and maintenance of olfactory glomerular circuitry. Mice expressing a mutant version of Shh (Shh(Ala/Ala)), with impaired binding to proteoglycan co-receptors, exhibit disproportionately small olfactory bulbs containing fewer glomeruli. Notably, in mutant animals the correspondence between individual glomeruli and specific olfactory receptors is lost, as olfactory sensory neurons expressing different olfactory receptors converge on the same glomeruli. These deficits arise at late stages in post-natal development and continue into adulthood, indicating impaired pruning of erroneous connections within the olfactory bulb. In addition, mature Shh(Ala/Ala) mice exhibit decreased proliferation in the subventricular zone (SVZ), with particular reduction in neurogenesis of calbindin-expressing periglomerular cells. Thus, Shh interactions with proteoglycan co-receptors function at multiple locations to regulate neurogenesis and precise olfactory connectivity, thereby promoting functional neuronal circuitry.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

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

    2011-10-19

    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.

  16. Harmful effects of cadmium on olfactory system in mice.

    Science.gov (United States)

    Bondier, Jean-Robert; Michel, Germaine; Propper, Alain; Badot, Pierre-Marie

    2008-10-01

    The inhalation of certain metals can result in olfactory epithelial injury, an altered sense of smell, and direct delivery of the metal from the olfactory epithelium to the olfactory bulbs and other parts of the central nervous system. The purpose of this study was to examine whether mice given an intranasal instillation of cadmium would develop altered olfactory function and to assess whether cadmium may be transported directly from the olfactory epithelium to the central nervous system. To evaluate cadmium's ability to induce anosmia and on the basis of olfactory epithelium sensitivity to metals, the aim of this study was first to study cadmium effects on the olfactory function and secondly to check whether cadmium may be transported from the nasal area to the central nervous system. After an intranasal instillation of a solution containing CdCl2 at 136 mM, we observed in treated mice: (1) a partial destruction of the olfactory epithelium, which is reduced to three or four basal cell layers followed by a progressive regeneration; (2) a loss of odor discrimination with a subsequent recovery; and (3) a cadmium uptake by olfactory bulbs demonstrated using atomic absorption spectrophotometry, but not by other parts of the central nervous system. Cadmium was delivered to the olfactory bulbs, most likely along the olfactory nerve, thereby bypassing the intact blood-brain barrier. We consider that cadmium can penetrate olfactory epithelium and hence be transported to olfactory bulbs. The olfactory route could therefore be a likely way to reach the brain and should be taken into account for occupational risk assessments for this metal.

  17. Long-Lasting Metabolic Imbalance Related to Obesity Alters Olfactory Tissue Homeostasis and Impairs Olfactory-Driven Behaviors.

    Science.gov (United States)

    Lacroix, Marie-Christine; Caillol, Monique; Durieux, Didier; Monnerie, Régine; Grebert, Denise; Pellerin, Luc; Repond, Cendrine; Tolle, Virginie; Zizzari, Philippe; Baly, Christine

    2015-10-01

    Obesity is associated with chronic food intake disorders and binge eating. Food intake relies on the interaction between homeostatic regulation and hedonic signals among which, olfaction is a major sensory determinant. However, its potential modulation at the peripheral level by a chronic energy imbalance associated to obese status remains a matter of debate. We further investigated the olfactory function in a rodent model relevant to the situation encountered in obese humans, where genetic susceptibility is juxtaposed on chronic eating disorders. Using several olfactory-driven tests, we compared the behaviors of obesity-prone Sprague-Dawley rats (OP) fed with a high-fat/high-sugar diet with those of obese-resistant ones fed with normal chow. In OP rats, we reported 1) decreased odor threshold, but 2) poor olfactory performances, associated with learning/memory deficits, 3) decreased influence of fasting, and 4) impaired insulin control on food seeking behavior. Associated with these behavioral modifications, we found a modulation of metabolism-related factors implicated in 1) electrical olfactory signal regulation (insulin receptor), 2) cellular dynamics (glucorticoids receptors, pro- and antiapoptotic factors), and 3) homeostasis of the olfactory mucosa and bulb (monocarboxylate and glucose transporters). Such impairments might participate to the perturbed daily food intake pattern that we observed in obese animals. © The Author 2015. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  18. Compared the abilities of repairing nerve defect between glial cells in lamina propria and in olfactory bulb%嗅黏膜与嗅球神经层胶质细胞修复神经缺损能力的比较

    Institute of Scientific and Technical Information of China (English)

    刘夫海; 陈统一

    2009-01-01

    目的 比较嗅黏膜胶质细胞与嗅球神经层胶质细胞修复周围神经缺损的能力.方法 体外培养异体嗅黏膜胶质细胞及嗅球神经层胶质细胞2周后纯化浓缩待用.将60只成年Wistar鼠随机分为对照组(A组,n=20)、嗅球神经层胶质细胞组(B组,n=20)及嗅黏膜胶质细胞组(C组,n=20).左侧坐骨神经切除25mm长轴突,保留神经外膜吻合于近端,将细胞培养液、嗅球神经层胶质细胞、嗅黏膜胶质细胞分别注入A、B、C各组神经外膜腔内.术后3个月,通过大体形态、光学显微镜及透射电镜观察、逆行标记荧光金运输距离、免疫荧光检测胶质纤维酸性蛋白(glial fibre acid protein,GFAP)浓度及神经生长因子(nerve growth factors,NGF)浓度,酶联免疫方法检测髓鞘碱性蛋白(myelin basic protein,MBP)浓度及神经丝蛋白(neurofilament,NF)浓度,伤肢功能评分评估神经缺损的修复效果.结果 大体观察、光学显微镜及透射电镜观察,神经缺损再生C组最完全,A组最差;荧光金在神经中的运行距离,C组最长,A组最短;NGF、GFAP、MBP及NF浓度、伤肢功能评分均为C组最高,A组最低.结论 嗅黏膜胶质细胞及嗅球神经层胶质细胞均能促进坐骨神经缺损再生,嗅黏膜胶质细胞促进神经再生效果优于嗅球神经层胶质细胞.%Objective To compare their competence to repair peripheral nerve defect between lami-na propria glial cells and olfactory bulb glial cells. Methods Glial cells in nasal lamina propria and olfac-tory bulb had been cultured in vitro for 2 weeks, then purified and condensed for later transplantation. 60 adult wistar rats were randomized into three groups of 20 rats each: A (control), B (glial cells in olfactory bulb were transplanted into epineuria lumen) and C (glial cells in lamina propria were transplanted into epineuria lumen). Rats' left sciatic nerves were excised 25 mm long axons and retained epineuria lumen anastomosed to proximal

  19. Drosophila Mutant Model of Parkinson's Disease Revealed an Unexpected Olfactory Performance: Morphofunctional Evidences

    Science.gov (United States)

    De Rose, Francescaelena; Corda, Valentina; Belcari, Antonio; Poddighe, Simone; Marrosu, Francesco

    2016-01-01

    Parkinson's disease (PD) is one of the most common neurodegenerative diseases characterized by the clinical triad: tremor, akinesia, and rigidity. Several studies have suggested that PD patients show disturbances in olfaction as one of the earliest, nonspecific nonmotor symptoms of disease onset. We sought to use the fruit fly Drosophila melanogaster as a model organism to explore olfactory function in LRRK loss-of-function mutants, which was previously demonstrated to be a useful model for PD. Surprisingly, our results showed that the LRRK mutant, compared to the wild flies, presents a dramatic increase in the amplitude of the electroantennogram responses and this is coupled with a higher number of olfactory sensilla. In spite of the above reported results, the behavioural response to olfactory stimuli in mutant flies is impaired compared to that obtained in wild type flies. Thus, behaviour modifications and morphofunctional changes in the olfaction of LRRK loss-of-function mutants might be used as an index to explore the progression of parkinsonism in this specific model, also with the aim of studying and developing new treatments. PMID:27648340

  20. Olfactory sensor processing in neural networks: lessons from modeling the fruit fly antennal lobe

    Directory of Open Access Journals (Sweden)

    J. Henning Proske

    2012-02-01

    Full Text Available The insect olfactory system can be a model for artificial olfactory devices. In particular, Drosophila melanogaster due to its genetic tractability has yielded much information about the design and function of such systems in biology. In this study we investigate possible network topologies to separate representations of odors in the primary olfactory neuropil, the antennal lobe. In particular we compare networks based on stochastic and homogeneous connection weight distributions to connectivities that are based on the input correlations between the glomeruli in the antennal lobe. We show that moderate homogeneous inhibition implements a soft winner-take-all mechanism when paired with realistic input from a database of odor responses in receptor cells. The sparseness of representations increases with stronger inhibition. Excitation, on the other hand, pushes the representation of odors closer together thus making them harder to distinguish. We further analyze the relationship between different inhibitory network topologies and the properties of the receptor responses to different odors. We show that realistic input from the database has a relatively high entropy of activation values over all odors and receptors compared to the theoretical maximum. Furthermore, under conditions in which the information in the input is artificially decreased, networks with heterogeneous topologies based on the similarity of glomerular response profiles perform best. These results indicate that in order to arrive at the most beneficial representation for odor discrimination it is important to finely tune the strength of inhibition in combination with taking into account the properties of the available sensors.

  1. Progress in bionic information processing techniques for an electronic nose based on olfactory models

    Institute of Scientific and Technical Information of China (English)

    LI Guang; FU Jun; ZHANG Jia; ZHENG JunBao

    2009-01-01

    As a novel bionic analytical technique, an electronic nose, inspired by the mechanism of the biological olfactory system and integrated with modern sensing technology, electronic technology and pattern recognition technology, has been widely used in many areas. Moreover, recent basic research findings in biological olfaction combined with computational neuroscience promote its development both in methodology and application. In this review, the basic information processing principle of biological olfaction and artificial olfaction are summarized and compared, and four olfactory models and their applications to electronic noses are presented. Finally, a chaotic olfactory neural network is detailed and the utilization of several biologically oriented learning rules and its spatiotemporal dynamic prop-ties for electronic noses are discussed. The integration of various phenomena and their mechanisms for biological olfaction into an electronic nose context for information processing will not only make them more bionic, but also perform better than conventional methods. However, many problems still remain, which should be solved by further cooperation between theorists and engineers.

  2. 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

    The ectodomain of olfactory cell adhesion molecule (OCAM/NCAM2/RNCAM) consists of five immunoglobulin (Ig) domains (IgI-V), followed by two fibronectin-type 3 (Fn3) domains (Fn3I-II). A complete structural model of the entire ectodomain of human OCAM has been assembled from crystal structures...... 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...

  3. Model of Calcium Oscillations Due to Negative Feedback in Olfactory Cilia

    DEFF Research Database (Denmark)

    Reidl, Juergen; Borowski, Peter; Sensse, Anke;

    2006-01-01

    We present a mathematical model for Ca oscillations in the cilia of olfactory sensory neurons. The underlying mechanism is based on direct negative regulation of cyclic nucleotide-gated channels by calcium/calmodulin and does not require any autocatalysis such as calcium-induced calcium release....... The model is in quantitative agreement with available experimental data, both with respect to oscillations and to fast adaptation. We give predictions for the ranges of parameters in which oscillations should be observable. Relevance of the model to calcium oscillations in other systems is discussed....

  4. Profiling of olfactory receptor gene expression in whole human olfactory mucosa.

    Directory of Open Access Journals (Sweden)

    Christophe Verbeurgt

    Full Text Available Olfactory perception is mediated by a large array of olfactory receptor genes. The human genome contains 851 olfactory receptor gene loci. More than 50% of the loci are annotated as nonfunctional due to frame-disrupting mutations. Furthermore haplotypic missense alleles can be nonfunctional resulting from substitution of key amino acids governing protein folding or interactions with signal transduction components. Beyond their role in odor recognition, functional olfactory receptors are also required for a proper targeting of olfactory neuron axons to their corresponding glomeruli in the olfactory bulb. Therefore, we anticipate that profiling of olfactory receptor gene expression in whole human olfactory mucosa and analysis in the human population of their expression should provide an opportunity to select the frequently expressed and potentially functional olfactory receptors in view of a systematic deorphanization. To address this issue, we designed a TaqMan Low Density Array (Applied Biosystems, containing probes for 356 predicted human olfactory receptor loci to investigate their expression in whole human olfactory mucosa tissues from 26 individuals (13 women, 13 men; aged from 39 to 81 years, with an average of 67±11 years for women and 63±12 years for men. Total RNA isolation, DNase treatment, RNA integrity evaluation and reverse transcription were performed for these 26 samples. Then 384 targeted genes (including endogenous control genes and reference genes specifically expressed in olfactory epithelium for normalization purpose were analyzed using the same real-time reverse transcription PCR platform. On average, the expression of 273 human olfactory receptor genes was observed in the 26 selected whole human olfactory mucosa analyzed, of which 90 were expressed in all 26 individuals. Most of the olfactory receptors deorphanized to date on the basis of sensitivity to known odorant molecules, which are described in the literature, were

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

    Directory of Open Access Journals (Sweden)

    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.

  6. 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.

  7. Tracing neuronal tracts in the olfactory pathway of rat and detecting ischemic core in a rat model of focal ischemia using manganese enhanced magnetic resonance imaging

    Institute of Scientific and Technical Information of China (English)

    FANG Ke; LI Yingxia; LIU Hua; LIAO Weijing; LEI Hao

    2004-01-01

    Manganese enhanced magnetic resonance im aging (MRI) is a novel neuroimaging technique that can be used in vivo to trace neuronal tract and to study brain functions dynamically. In this study, manganese enhanced MRI was used to trace the neuronal tracts between the laminar structures of the olfactory bulb (OB) in rat and to study the so-called "calcium overload" phenomenon in a rat model of cerebral ischemia. High spatial resolution images of the OB were obtained and used to measure the transportation rate of Mn2+ among the laminar structures of the OB, which was shown to be approximately 0.2 mm/h under resting condition. In the rat focal ischemia study, it was found that the total area of brain regions with Mnz+ accumulation (representing brain regions with calcium overload) was only 55%±15% of the area of the ischemic brain regions shown by diffusion-weighted imaging (DWI). Manganese enhanced MRI might be more accurate than DWI in detecting the ischemic core at the early stage of experimental cerebral ischemia.

  8. Olfactory system oscillations across phyla.

    Science.gov (United States)

    Kay, Leslie M

    2015-04-01

    Neural oscillations are ubiquitous in olfactory systems of mammals, insects and molluscs. Neurophysiological and computational investigations point to common mechanisms for gamma or odor associated oscillations across phyla (40-100Hz in mammals, 20-30Hz in insects, 0.5-1.5Hz in molluscs), engaging the reciprocal dendrodendritic synapse between excitatory principle neurons and inhibitory interneurons in the olfactory bulb (OB), antennal lobe (AL), or procerebrum (PrC). Recent studies suggest important mechanisms that may modulate gamma oscillations, including neuromodulators and centrifugal input to the OB and AL. Beta (20Hz) and theta (2-12Hz) oscillations coordinate activity within and across brain regions. Olfactory beta oscillations are associated with odor learning and depend on centrifugal OB input, while theta oscillations are strongly associated with respiration.

  9. Exotic models may offer unique opportunities to decipher specific scientific question: the case of Xenopus olfactory system.

    Science.gov (United States)

    Gascuel, Jean; Amano, Tosikazu

    2013-09-01

    The fact that olfactory systems are highly conserved in all animal species from insects to mammals allow the generalization of findings from one species to another. Most of our knowledge about the anatomy and physiology of the olfactory system comes from data obtained in a very limited number of biological models such as rodents, Zebrafish, Drosophila, and a worm, Caenorhabditis elegans. These models have proved useful to answer most questions in the field of olfaction, and thus concentrating on these few models appear to be a pragmatic strategy. However, the diversity of the organization and physiology of the olfactory system amongst phyla appear to be greater than generally assumed and the four models alone may not be sufficient to address all the questions arising from the study of olfaction. In this article, we will illustrate the idea that we should take advantage of biological diversity to address specific scientific questions and will show that the Xenopus olfactory system is a very good model to investigate: first, olfaction in aerial versus aquatic conditions and second, mechanisms underlying postnatal reorganization of the olfactory system especially those controlled by tyroxine hormone.

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

    Energy Technology Data Exchange (ETDEWEB)

    Goektas, Oender [Department of Otolaryngology - Head and Neck Surgery, University of Berlin, Charite Campus Mitte, Smell and Taste Consultation Service, Berlin (Germany)], E-mail: oender.goektas@charite.de; Fleiner, Franca; Sedlmaier, Benedikt [Department of Otolaryngology - Head and Neck Surgery, University of Berlin, Charite Campus Mitte, Smell and Taste Consultation Service, Berlin (Germany); Bauknecht, Christian [Department of Radiology, University of Berlin, Charite Campus Mitte, Berlin (Germany)

    2009-09-15

    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.

  11. Time to smell: a cascade model of human olfactory perception based on response-time (RT) measurement.

    Science.gov (United States)

    Olofsson, Jonas K

    2014-01-01

    The timing of olfactory behavioral decisions may provide an important source of information about how the human olfactory-perceptual system is organized. This review integrates results from olfactory response-time (RT) measurements from a perspective of mental chronometry. Based on these findings, a new cascade model of human olfaction is presented. Results show that main perceptual decisions are executed with high accuracy within about 1~s of sniff onset. The cascade model proposes the existence of distinct processing stages within this brief time-window. According to the cascade model, different perceptual features become accessible to the perceiver at different time-points, and the output of earlier processing stages provides the input for later processing stages. The olfactory cascade starts with detecting the odor, which is followed by establishing an odor object. The odor object, in turn, triggers systems for determining odor valence and edibility. Evidence for the cascade model comes from studies showing that RTs for odor valence and edibility assessment are predicted by the shorter RTs needed to establish the odor object. Challenges for future research include innovative task designs for olfactory RT experiments and the integration of the behavioral processing sequence into the underlying cortical processes using complementary RT measures and neuroimaging methods.

  12. Modelling spatiotemporal olfactory data in two steps: from binary to Hodgkin-Huxley neurones.

    Science.gov (United States)

    Quenet, Brigitte; Dubois, Rémi; Sirapian, Sevan; Dreyfus, Gérard; Horn, David

    2002-01-01

    Network models of synchronously updated McCulloch-Pitts neurones exhibit complex spatiotemporal patterns that are similar to activities of biological neurones in phase with a periodic local field potential, such as those observed experimentally by Wehr and Laurent (1996, Nature 384, 162-166) in the locust olfactory pathway. Modelling biological neural nets with networks of simple formal units makes the dynamics of the model analytically tractable. It is thus possible to determine the constraints that must be satisfied by its connection matrix in order to make its neurones exhibit a given sequence of activity (see, for instance, Quenet et al., 2001, Neurocomputing 38-40, 831-836). In the present paper, we address the following question: how can one construct a formal network of Hodgkin-Huxley (HH) type neurones that reproduces experimentally observed neuronal codes? A two-step strategy is suggested in the present paper: first, a simple network of binary units is designed, whose activity reproduces the binary experimental codes; second, this model is used as a guide to design a network of more realistic formal HH neurones. We show that such a strategy is indeed fruitful: it allowed us to design a model that reproduces the Wehr-Laurent olfactory codes, and to investigate the robustness of these codes to synaptic noise.

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

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    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.

  14. Interactions with the young down-regulate adult olfactory neurogenesis and enhance the maturation of olfactory neuroblasts in sheep mothers.

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    Maïna eBRUS

    2014-02-01

    Full Text Available New neurons are continuously added in the dentate gyrus and the olfactory bulb of mammalian brain. While numerous environmental factors controlling survival of newborn neurons have been extensively studied, regulation by social interactions is less documented. We addressed this question by investigating the influence of parturition and interactions with the young on neurogenesis in sheep mothers. Using Bromodeoxyuridine, a marker of cell division, in combination with markers of neuronal maturation, the percentage of neuroblasts and new mature neurons in the olfactory bulb and the dentate gyrus was compared between groups of parturient ewes which could interact or not with their lamb, and virgins. In addition, a morphological analysis was performed by measuring the dendritic arbor of neuroblasts in both structures. We showed that the post-partum period was associated with a decrease in olfactory and hippocampal adult neurogenesis. In the olfactory bulb, the suppressive effect on neuroblasts was dependent on interactions with the young whereas in the dentate gyrus the decrease in new mature neurons was associated with parturition. In addition, dendritic length and number of nodes of neuroblasts were significantly enhanced by interactions with the lamb in the olfactory bulb but not in the dentate gyrus. Because interactions with the young involved learning of the olfactory signature of the lamb, we hypothesize that this learning is associated with a down-regulation in olfactory neurogenesis and an enhancement of olfactory neuroblast maturation. Our assumption is that fewer new neurons decrease cell competition in the olfactory bulb and enhance maturation of those new neurons selected to participate in the learning of the young odor.

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

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    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.

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

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    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.

  17. Nasal toxicity, carcinogenicity, and olfactory uptake of metals.

    Science.gov (United States)

    Sunderman, F W

    2001-01-01

    Occupational exposures to inhalation of certain metal dusts or aerosols can cause loss of olfactory acuity, atrophy of the nasal mucosa, mucosal ulcers, perforated nasal septum, or sinonasal cancer. Anosmia and hyposmia have been observed in workers exposed to Ni- or Cd-containing dusts in alkaline battery factories, nickel refineries, and cadmium industries. Ulcers of the nasal mucosa and perforated nasal septum have been reported in workers exposed to Cr(VI) in chromate production and chrome plating, or to As(III) in arsenic smelters. Atrophy of the olfactory epithelium has been observed in rodents following inhalation of NiSO4 or alphaNi3S2. Cancers of the nose and nasal sinuses have been reported in workers exposed to Ni compounds in nickel refining, cutlery factories, and alkaline battery manufacture, or to Cr(VI) in chromate production and chrome plating. In animals, several metals (eg, Al, Cd, Co, Hg, Mn, Ni, Zn) have been shown to pass via olfactory receptor neurons from the nasal lumen through the cribriform plate to the olfactory bulb. Some metals (eg, Mn, Ni, Zn) can cross synapses in the olfactory bulb and migrate via secondary olfactory neurons to distant nuclei of the brain. After nasal instillation of a metal-containing solution, transport of the metal via olfactory axons can occur rapidly, within hours or a few days (eg, Mn), or slowly over days or weeks (eg, Ni). The olfactory bulb tends to accumulate certain metals (eg, Al, Bi, Cu, Mn, Zn) with greater avidity than other regions of the brain. The molecular mechanisms responsible for metal translocation in olfactory neurons and deposition in the olfactory bulb are unclear, but complexation by metal-binding molecules such as carnosine (beta-alanyl-L-histidine) may be involved.

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

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    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

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

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    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.

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

    Institute of Scientific and Technical Information of China (English)

    Hao Zhao; Qing Li; Bao-lin Yang; Zeng-xu Liu; Qing Yu; Wen-jun Zhang; Keng Yuan; Hui-hong Zeng; Gao-chun Zhu; De-ming Liu

    2015-01-01

    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 puriifed transplanted olfactory ensheathing cells (OECs) remains unclear. In the present study, we microencapsulated OECs in alginic acid, and transplanted free and microen-capsulated 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 L4–5 dorsal root ganglia using immunohistochemistry. Rats that received free and microencap-sulated 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 conifrm that microencapsulated OEC transplantation suppresses P2X2/3 receptor expression in L4–5 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.

  1. Bilateral olfactory ensheathing cell transplantation promotes neurological function in a rat model of cerebral infarction

    Institute of Scientific and Technical Information of China (English)

    Zhihua Yang; Wenli Sheng; Huiyong Shen; Qinghua Hou; Rui Li; Jinsheng Zeng; Ruxun Huang

    2011-01-01

    In the present study, olfactory ensheathing cells were transplanted into the cortices of infarcted (infarct transplantation group), normal (normal transplantation group), and bilateral hemispheres (bilateral transplantation group). Olfactory ensheathing cells migrated to the infarct focus. The number of growth associated protein 43-positive cells and nerve fibers was slightly increased in the infarct area. These changes were more evident in the bilateral cortical transplantation group. Results demonstrated that transplanted olfactory ensheathing cells can migrate in rats with cerebral infarction. The olfactory ensheathing cells on the normal side can also promote neurological function. Bilateral cortical transplantation exhibited superior effects over unilateral transplantation.

  2. Environmental toxicants-induced immune responses in the olfactory mucosa

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    Fumiaki Imamura

    2016-11-01

    Full Text Available Olfactory sensory neurons (OSNs are the receptor cells for the sense of smell. Although cell bodies are located in the olfactory mucosa of the nasal cavity, OSN axons directly project to the olfactory bulb that is a component of the central nervous system (CNS. Because of this direct and short connection from this peripheral tissue to the CNS, the olfactory system has attracted attention as a port-of-entry for environmental toxicants that may cause neurological dysfunction. Selected viruses can enter the olfactory bulb via the olfactory mucosa, and directly affect the CNS. On the other hand, environmental toxicants may induce inflammatory responses in the olfactory mucosa, including infiltration of immune cells and production of inflammatory cytokines. In addition, these inflammatory responses cause the loss of OSNs that are then replaced with newly generated OSNs that re-connect to the olfactory bulb after inflammation has subsided. It is now known that immune cells and cytokines in the olfactory mucosa play important roles in both degeneration and regeneration of OSNs. Thus, the olfactory system is a unique neuroimmune interface where interaction between nervous and immune systems in the periphery significantly affects the structure, neuronal circuitry, and immunological status of the CNS. The mechanisms by which immune cells regulate OSN loss and the generation of new OSNs are, however, largely unknown. To help develop a better understanding of the mechanisms involved, we have provided a review of key research that has investigated how the immune response in the olfactory mucosa affects the pathophysiology of OSNs.

  3. An Information Theoretic Model of Information Processing in the Drosophila Olfactory System: the Role of Inhibitory Neurons for System Efficiency

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    Faramarz eFaghihi

    2013-12-01

    Full Text Available 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's efficiency will be substantially reduced.

  4. Holocranohistochemistry enables the visualization of α-synuclein expression in the murine olfactory system and discovery of its systemic anti-microbial effects.

    Science.gov (United States)

    Tomlinson, Julianna J; Shutinoski, Bojan; Dong, Li; Meng, Fanyi; Elleithy, Dina; Lengacher, Nathalie A; Nguyen, Angela P; Cron, Greg O; Jiang, Qiubo; Roberson, Erik D; Nussbaum, Robert L; Majbour, Nour K; El-Agnaf, Omar M; Bennett, Steffany A; Lagace, Diane C; Woulfe, John M; Sad, Subash; Brown, Earl G; Schlossmacher, Michael G

    2017-06-01

    Braak and Del Tredici have proposed that typical Parkinson disease (PD) has its origins in the olfactory bulb and gastrointestinal tract. However, the role of the olfactory system has insufficiently been explored in the pathogeneses of PD and Alzheimer disease (AD) in laboratory models. Here, we demonstrate applications of a new method to process mouse heads for microscopy by sectioning, mounting, and staining whole skulls ('holocranohistochemistry'). This technique permits the visualization of the olfactory system from the nasal cavity to mitral cells and dopamine-producing interneurons of glomeruli in the olfactory bulb. We applied this method to two specific goals: first, to visualize PD- and AD-linked gene expression in the olfactory system, where we detected abundant, endogenous α-synuclein and tau expression in the olfactory epithelium. Furthermore, we observed amyloid-β plaques and proteinase-K-resistant α-synuclein species, respectively, in cranial nerve-I of APP- and human SNCA-over-expressing mice. The second application of the technique was to the modeling of gene-environment interactions in the nasal cavity of mice. We tracked the infection of a neurotropic respiratory-enteric-orphan virus from the nose pad into cranial nerves-I (and -V) and monitored the ensuing brain infection. Given its abundance in the olfactory epithelia, we questioned whether α-synuclein played a role in innate host defenses to modify the outcome of infections. Indeed, Snca-null mice were more likely to succumb to viral encephalitis versus their wild-type littermates. Moreover, using a bacterial sepsis model, Snca-null mice were less able to control infection after intravenous inoculation with Salmonella typhimurium. Together, holocranohistochemistry enabled new discoveries related to α-synuclein expression and its function in mice. Future studies will address: the role of Mapt and mutant SNCA alleles in infection paradigms; the contribution of xenobiotics in the initiation

  5. Hypothalamus-Olfactory System Crosstalk: Orexin as a Connecting Track in Mice.

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    Jean eGascuel

    2012-11-01

    Full Text Available It is well known that olfaction influences food intake, and almost vice versa, the nutritional status of individuals modulates olfactory sensitivity. However, the neuronal correlate of this relationship and the connections between the olfactory bulb and the hypothalamus is still poorly understood. The goal of this report is to analyze the type of connections between the olfactory bulb and hypothalamus focusing on the expression pattern of orexin A, a hypothalamic neuropeptide that is thought to play a role in sleep/wakefulness states. Interestingly, orexin A has also been described as a stimulator of food intake. Such an effect may be due in part to the stimulation of the olfactory bulbar pathway. In rats, orexin positive cells are strictly concentrated in the lateral hypothalamus while their projections invade nearly the entire brain including the olfactory system. Therefore, orexin appears to be a good candidate to play a pivotal role in connecting olfactory and hypothalamic pathways. So far, orexin expression has been described in rats but there is still a lack of information concerning its expression in the adult and developing mouse brain. In this context we revisited the orexin A expression pattern in adult and developing mice using immunohistological methods and confocal microscopy. Besides minor differences, we found that the expression pattern of orexin A in mice shares many features with that in rats. In the olfactory bulb, even though there are few orexin projections, they reach all the different layers of the olfactory bulb. In contrast with the presence of orexin projections in the Main Olfactory Bulb almost none have been found in the Accessory Olfactory Bulb. The developmental expression of orexin A supports the hypothesis that orexin expression only appears post-natally.

  6. Brain-derived neurotrophic factor (BDNF) expression in normal and regenerating olfactory epithelium of Xenopus laevis.

    Science.gov (United States)

    Frontera, Jimena Laura; Cervino, Ailen Soledad; Jungblut, Lucas David; Paz, Dante Agustín

    2015-03-01

    Olfactory epithelium has the capability to continuously regenerate olfactory receptor neurons throughout life. Adult neurogenesis results from proliferation and differentiation of neural stem cells, and consequently, olfactory neuroepithelium offers an excellent opportunity to study neural regeneration and the factors involved in the maintenance and regeneration of all their cell types. We analyzed the expression of BDNF in the olfactory system under normal physiological conditions as well as during a massive regeneration induced by chemical destruction of the olfactory epithelium in Xenopus laevis larvae. We described the expression and presence of BDNF in the olfactory epithelium and bulb. In normal physiological conditions, sustentacular (glial) cells and a few scattered basal (stem) cells express BDNF in the olfactory epithelium as well as the granular cells in the olfactory bulb. Moreover, during massive regeneration, we demonstrated a drastic increase in basal cells expressing BDNF as well as an increase in BDNF in the olfactory bulb and nerve. Together these results suggest an important role of BDNF in the maintenance and regeneration of the olfactory system.

  7. Microanatomy and surgical relevance of the olfactory cistern.

    Science.gov (United States)

    Wang, Shou-Sen; Zheng, He-Ping; Zhang, Xiang; Zhang, Fa-Hui; Jing, Jun-Jie; Wang, Ru-Mi

    2008-01-01

    All surgical approaches to the anterior skull base involve the olfactory cistern and have the risk of damaging the olfactory nerve. The purpose of this study was to describe the microanatomical features of the olfactory cistern and discuss its surgical relevance. In this study, the olfactory cisterns of 15 formalin-fixed adult cadaveric heads were dissected using a surgical microscope. The results showed that the olfactory cistern was situated in the superficial part of the olfactory sulcus, which separated the gyrus retus from the orbital gyrus. In coronal section, the cistern was triangular in shape; its anterior part enveloped the olfactory bulbs and was high and broad; its posterior part was medial-superior to internal carotid artery and was also much broader. There were one or several openings in the inferior wall of the posterior part in 53.4% of the cisterns. The olfactory cistern communicated with the surrounding subarachnoind cisterns through these openings. The middle part of the olfactory cistern gradually narrowed down posteriorly. Most cisterns were spacious with a few fibrous trabeculas and bands between the olfactory nerves and cistern walls. However 23% of the cisterns were narrow with the cistern walls tightly encasing the olfactory nerve. There were two or three of arterial loops in each olfactory sulcus, from which long, fine olfactory arteries originated. The olfactory arteries coursed along the olfactory nerve and gave off many terminal branches to provide the main blood supply to the olfactory nerve in most cisterns, but the blood supply was in segmental style in a few cisterns. Moreover, the veins of the cistern appeared to be more segmental than the olfactory arteries in most cisterns. These results suggested that most olfactory cisterns are spacious with relatively independent blood supply, and it is reasonable to separate the olfactory tract with its independent blood supply from the frontal lobe by 1-2 cm in the subfrontal approach, the

  8. 新生小鼠海马、嗅球及皮质神经干细胞的分离培养及鉴定%Isolation and identification of neural stem cells from newborn mouse hippocampus, olfactory bulb and cortex

    Institute of Scientific and Technical Information of China (English)

    马浚宁; 高俊玮; 侯博儒; 任海军; 陈四化; 刘吉星; 严贵忠

    2014-01-01

    背景:从体外分离培养出高纯度、生物学性能均一的神经干细胞,建立起一套完整的神经干细胞培养体系,是进行神经干细胞研究的基础。  目的:建立新生小鼠海马、嗅球、皮质组织神经干细胞的分离培养体系,并对其生物学特性进行分析。  方法:分离新生昆明小鼠海马、嗅球、皮质组织,采用机械分离和胰酶消化法提取原代神经干细胞。采用无血清培养技术、机械吹打和酶消化法进行传代培养神经干细胞。以体积分数为10%的胎牛血清诱导分化神经干细胞。对神经干细胞及其分化产物行CD133、巢蛋白、β-微管蛋白Ⅲ、胶质纤维酸性蛋白免疫荧光染色鉴定。  结果与结论:从新生小鼠海马、嗅球、皮质可提取出具有自我更新和多向分化能力的神经干细胞,经巢蛋白、CD133免疫荧光染色检测呈阳性;神经干细胞经胎牛血清诱导后可分化为β-微管蛋白Ⅲ、胶质纤维酸性蛋白阳性细胞,并证实染色阳性细胞为神经元和星形胶质细胞。该实验建立了一套神经干细胞体外分离培养、纯化、鉴定、诱导分化方案,为后续神经干细胞研究的顺利进行奠定了实验基础。%BACKGROUND:To in vitro isolate neural stem cel s with high purity and uniform biological properties and to establish a complete set of neural stem cel culture system is the basis for neural stem cel research. OBJECTIVE:To establish an isolation and culture system for neural stem cel s from newborn mouse hippocampus, olfactory bulb and cortex and to analyze the biological properties of cel s. METHODS:Neural stem cel s were isolated from the hippocampus, olfactory bulb and cortex tissue of newborn Kunming mice by mechanical separation and trypsin digestion. Serum-free culture technology, mechanical pipetting and trypsin digestion were used for subculture of neural stem cel s. 10%fetal bovine serum was used

  9. 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.

  10. Making scent of the presence and local translation of odorant receptor mRNAs in olfactory axons.

    Science.gov (United States)

    Dubacq, Caroline; Fouquet, Coralie; Trembleau, Alain

    2014-03-01

    Rodents contain in their genome more than 1000 functional odorant receptor genes, which are specifically expressed by the olfactory sensory neurons projecting from the olfactory epithelium to the olfactory bulb. Strong evidence for the presence and local translation of odorant receptor mRNAs in the axon of olfactory sensory neurons was obtained, but no function has been assigned to these axonal mRNAs yet. The aim of this review is to discuss the evidence for the presence and local translation of odorant receptor mRNAs in olfactory sensory axons, and to speculate on their possible function in the wiring of the mouse olfactory sensory projections.

  11. Olfactory Decoding Method Using Neural Spike Signals

    Institute of Scientific and Technical Information of China (English)

    Kyung-jin YOU; Hyun-chool SHIN

    2010-01-01

    This paper presents a travel method for inferring the odor based on naval activities observed from rats'main olfactory bulbs.Mufti-channel extmcellular single unit recordings are done by microwire electrodes(Tungsten,50μm,32 channels)innplanted in the mitral/tufted cell layers of the main olfactory bulb of the anesthetized rats to obtain neural responses to various odors.Neural responses as a key feature are measured by subtraction firing rates before stimulus from after.For odor irderenoe,a decoding method is developed based on the ML estimation.The results show that the average decoding acauacy is about 100.0%,96.0%,and 80.0% with three rats,respectively.This wait has profound implications for a novel brain-madune interface system far odor inference.

  12. 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%].

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

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    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].

  14. Effect of olfactory manganese exposure on anxiety-related behavior in a mouse model of iron overload hemochromatosis

    OpenAIRE

    Ye, Qi; Kim, Jonghan

    2015-01-01

    Manganese in excess promotes unstable emotional behavior. Our previous study showed that olfactory manganese uptake into the brain is altered in Hfe−/− mice, a model of iron overload hemochromatosis, suggesting that Hfe deficiency could modify the neurotoxicity of airborne manganese. We determined anxiety-related behavior and monoaminergic protein expression after repeated intranasal instillation of MnCl2 to Hfe−/− mice. Compared with manganese-instilled wild-type mice, Hfe−/− mice showed dec...

  15. Nogo-A expression in injured spinal cord following human olfactory mucosa-derived olfactory ensheathing cells transplantation

    Institute of Scientific and Technical Information of China (English)

    Bin Wang; Qiang Li; Xijing He; Weixiong Wang

    2011-01-01

    Transplantation of olfactory bulb-derived olfactory ensheathing cells (OECs) promotes motor functional recovery in rats with acute spinal cord injury, possibly by Nogo-A expression changes at the injury site. The present study transplanted OECs derived from the olfactory mucosa (OM) of rats. OM-derived OEC (OM-OEC) transplantation significantly reduced the increase of Nogo-A protein and mRNA expression caused by spinal cord injury, supporting the hypothesis that OM-OECs improve spinal cord regeneration by reducing Nogo-A expression.

  16. A patient-derived olfactory stem cell disease model for ataxia-telangiectasia.

    Science.gov (United States)

    Stewart, Romal; Kozlov, Sergei; Matigian, Nicholas; Wali, Gautam; Gatei, Magtouf; Sutharsan, Ratneswary; Bellette, Bernadette; Wraith-Kijas, Amanda; Cochrane, Julie; Coulthard, Mark; Perry, Chris; Sinclair, Kate; Mackay-Sim, Alan; Lavin, Martin F

    2013-06-15

    The autosomal recessive disorder ataxia-telangiectasia (A-T) is characterized by genome instability, cancer predisposition and neurodegeneration. Although the role of ataxia-telangiectasia mutated (ATM) protein, the protein defective in this syndrome, is well described in the response to DNA damage, its role in protecting the nervous system is less clear. We describe the establishment and characterization of patient-specific stem cells that have the potential to address this shortcoming. Olfactory neurosphere (ONS)-derived cells were generated from A-T patients, which expressed stem cell markers and exhibited A-T molecular and cellular characteristics that included hypersensitivity to radiation, defective radiation-induced signaling and cell cycle checkpoint defects. Introduction of full-length ATM cDNA into these cells corrected defects in the A-T cellular phenotype. Gene expression profiling and pathway analysis revealed defects in multiple cell signaling pathways associated with ATM function, with cell cycle, cell death and DNA damage response pathways being the most significantly dysregulated. A-T ONS cells were also capable of differentiating into neural progenitors, but they were defective in neurite formation, number of neurites and length of these neurites. Thus, ONS cells are a patient-derived neural stem cell model that recapitulate the phenotype of A-T, do not require genetic reprogramming, have the capacity to differentiate into neurons and have potential to delineate the neurological defect in these patients.

  17. Neural circuits mediating olfactory-driven behavior in fish

    Directory of Open Access Journals (Sweden)

    Florence eKermen

    2013-04-01

    Full Text Available The fish olfactory system processes odor signals and mediates behaviors that are crucial for survival such as foraging, courtship and alarm response. Although the upstream olfactory brain areas (olfactory epithelium and olfactory bulb are well studied, less is known about their target brain areas and the role they play in generating odor-driven behaviors. Here we review a broad range of literature on the anatomy, physiology and behavioral output of the olfactory system and its target areas in a wide range of teleost fish. Additionally, we discuss how applying recent technological advancements to the zebrafish (Danio rerio could help in understanding the function of these target areas. We hope to provide a framework for elucidating the neural circuit computations underlying the odor-driven behaviors in this small, transparent and genetically amenable vertebrate.

  18. 基于LM-BP神经网络的湿球温度计算模型%Wet-bulb Temperature Calculation Model Based on Levenberg-Marquardt BP Neural Network

    Institute of Scientific and Technical Information of China (English)

    林婵; 王起峰; 朱良山

    2013-01-01

    湿球温度是电力工程中常用的气象设计参数,而目前气象站安装的地面气象自动观测设备中无湿球温度观测工具,且已有的湿球温度计算方法存在不足.为了满足工程设计需要,分析了湿球温度与干球温度、相对湿度、大气压强及平均风速等4个气象参数的非线性关系,建立了基于LM-BP神经网络的湿球温度计算模型,并将其应用于潍坊气象站湿球温度计算中.结果表明,该模型计算精度较高,且较为合理地反映了湿球温度与干球温度等影响因子之间复杂的非线性关系.%The wet-bulb temperature is a common weather parameter in power engineering design, but at present most ground automatic weather observation equipments installed in the weather station do not include the wet-bulb temperature observation equipment. The common wet-bulb temperature calculation methods have shortcomings. In order to meet the needs in engineering design, this paper analyzes the non-linear relationship between wet-bulb temperature and four meteorological parameters, which include dry-bulb temperature, relative humidity, atmospheric pressure and wind speed. And then it established a wet-bulb temperature calculation model based on Levenberg-Marquardt BP neural network. Finally, this model is applied to calculate wet-bulb temperature in Weifang weather station. The results show that the proposed model has high precision and it can well reflect the non-linear relationship between wet-bulb temperature and dry-bulb temperature.

  19. 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.

  20. Satratoxin G from the black mold Stachybotrys chartarum evokes olfactory sensory neuron loss and inflammation in the murine nose and brain.

    Science.gov (United States)

    Islam, Zahidul; Harkema, Jack R; Pestka, James J

    2006-07-01

    Satratoxin G (SG) is a macrocyclic trichothecene mycotoxin produced by Stachybotrys chartarum, the "black mold" suggested to contribute etiologically to illnesses associated with water-damaged buildings. Using an intranasal instillation model in mice, we found that acute SG exposure specifically induced apoptosis of olfactory sensory neurons (OSNs) in the olfactory epithelium. Dose-response analysis revealed that the no-effect and lowest-effect levels at 24 hr postinstillation (PI) were 5 and 25 microg/kg body weight (bw) SG, respectively, with severity increasing with dose. Apoptosis of OSNs was identified using immunohistochemistry for caspase-3 expression, electron microscopy for ultrastructural cellular morphology, and real-time polymerase chain reaction for elevated expression of the proapoptotic genes Fas, FasL, p75NGFR, p53, Bax, caspase-3, and CAD. Time-course studies with a single instillation of SG (500 microg/kg bw) indicated that maximum atrophy of the olfactory epithelium occurred at 3 days PI. Exposure to lower doses (100 microg/kg bw) for 5 consecutive days resulted in similar atrophy and apoptosis, suggesting that in the short term, these effects are cumulative. SG also induced an acute, neutrophilic rhinitis as early as 24 hr PI. Elevated mRNA expression for the proinflammatory cytokines tumor necrosis factor-alpha, interleukin-6 (IL-6) , and IL-1 and the chemokine macrophage-inflammatory protein-2 (MIP-2) were detected at 24 hr PI in both the ethmoid turbinates of the nasal airways and the adjacent olfactory bulb of the brain. Marked atrophy of the olfactory nerve and glomerular layers of the olfactory bulb was also detectable by 7 days PI along with mild neutrophilic encephalitis. These findings suggest that neurotoxicity and inflammation within the nose and brain are potential adverse health effects of exposure to satratoxins and Stachybotrys in the indoor air of water-damaged buildings.

  1. Ship's stern bulb

    Energy Technology Data Exchange (ETDEWEB)

    Allan, R.G.; Diepen, P.J.

    1988-06-07

    This invention relates to the propulsion of self-propelled vessels, and in particular to the form of a ship's stern. The invention describes a new and distinctive form of bulbous-shaped stern from which, unlike other stern bulbs developed to date, does not fair into the hull, instead intersecting it to create a sharp discontinuity between surfaces. This discontinuity creates a turbulent zone along the said intersection, allowing the wake to reorganize and to follow in a desired pattern the bulb's shape in the proximity of the propeller. Thus a more uniform wake field is formed within the propeller disc, consequently improving propeller efficiency and reducing propeller induced vibration. These effects, which result in improved quietness and overall efficiency of a running propeller, along with other improved characteristics, have been confirmed by a preliminary series of model tests. The form of the bulb, and its attendant benefits, are described.

  2. 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…

  3. 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…

  4. 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

    2010-01-01

    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. PMID:21290004

  5. 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.

  6. Cladistic analysis of olfactory and vomeronasal systems

    Directory of Open Access Journals (Sweden)

    Alino eMartinez-Marcos

    2011-01-01

    Full Text Available 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 sphericus 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.

  7. Olfactory route for cerebrospinal fluid drainage into the cervical lymphatic system in a rabbit experimental model

    Institute of Scientific and Technical Information of China (English)

    Haisheng Liu; Zhili Ni; Yetao Chen; Dong Wang; Yan Qi; Qiuhang Zhang; Shijie Wang

    2012-01-01

    The present study analyzed the anatomical association between intracranial subarachnoid space and the cervical lymphatic system. X-ray contrast medium and Microfil(R) (Microfil compounds fill and opacify microvascular and other spaces of non-surviving animals and post-mortem tissue under physiological injection pressure) were injected into the cisterna magna of the rabbit, and perineural routes of cerebrospinal fluid outflow into the lymphatic system were visualized. Under a surgical operating microscope, Microfil was found within the subarachnoid space and along the olfactory nerves. At the nasal mucosa, a lymphatic network was identified near the olfactory nerves, which crossed the nasopharyngeal region and finally emptied into the superficial and deep cervical lymph nodes. Under a light microscope, Microfil was visible around the olfactory nerves and within lymphatic vessels. These results suggested that cerebrospinal fluid drained from the subarachnoid space along the olfactory nerves to nasal lymphatic vessels, which in turn, emptied into the cervical lymph nodes. This anatomical route, therefore, allowed connection between the central nervous system and the lymphatic system.

  8. Rotenone Susceptibility Phenotype in Olfactory Derived Patient Cells as a Model of Idiopathic Parkinson's Disease.

    Directory of Open Access Journals (Sweden)

    M Murtaza

    Full Text Available Parkinson's disease is a complex age-related neurodegenerative disorder. Approximately 90% of Parkinson's disease cases are idiopathic, of unknown origin. The aetiology of Parkinson's disease is not fully understood but increasing evidence implies a failure in fundamental cellular processes including mitochondrial dysfunction and increased oxidative stress. To dissect the cellular events underlying idiopathic Parkinson's disease, we use primary cell lines established from the olfactory mucosa of Parkinson's disease patients. Previous metabolic and transcriptomic analyses identified deficiencies in stress response pathways in patient-derived cell lines. The aim of this study was to investigate whether these deficiencies manifested as increased susceptibility, as measured by cell viability, to a range of extrinsic stressors. We identified that patient-derived cells are more sensitive to mitochondrial complex I inhibition and hydrogen peroxide induced oxidative stress, than controls. Exposure to low levels (50 nM of rotenone led to increased apoptosis in patient-derived cells. We identified an endogenous deficit in mitochondrial complex I in patient-derived cells, but this did not directly correlate with rotenone-sensitivity. We further characterized the sensitivity to rotenone and identified that it was partly associated with heat shock protein 27 levels. Finally, transcriptomic analysis following rotenone exposure revealed that patient-derived cells express a diminished response to rotenone-induced stress compared with cells from healthy controls. Our cellular model of idiopathic Parkinson's disease displays a clear susceptibility phenotype to mitochondrial stress. The determination of molecular mechanisms underpinning this susceptibility may lead to the identification of biomarkers for either disease onset or progression.

  9. 面向仿生的嗅觉神经系统建模研究%Research on Olfactory Neural System Model Based on Bionics

    Institute of Scientific and Technical Information of China (English)

    张锦; 朱尚武; 王莹; 黄诗苹; 王如龙

    2011-01-01

    According to the biology characteristics of olfactory neural system,an olfactory neural system integrated model was proposed based on bionics.The proposed olfactory model simulated olfactory neural system from different aspects in order to make the model similar to the characteristics of olfactory neural system as soon as possible.Firstly,to the structure of olfactory neural system,the model simulated three key parts of olfactory neural system,the delay and feedback among them based on the anatomical structure of olfactory neural system.Secondly,to the neuron model,different models were used to simulate different neurons in different parts of olfactory neural system.Finally,to the dynamics of model,the model could give response to stimulus.When the stimulus is durative,the output of model shows steady pattern.When the special stimulus is inputted,the output of model shows the pattern of limit cycle.%着眼于嗅觉神经系统的生物学特点,从仿生学角度提出了一种嗅觉神经系统整合模型。模型从不同角度进行对嗅觉神经系统进行仿真,使其尽可能贴近嗅觉神经系统的生理学特征。首先,在结构上,根据嗅觉神经系统解剖结构,完整体现了嗅觉系统的三个关键部分,以及它们之间的延时和反馈链接。其次,在神经元模型上,根据嗅觉系统不同部分的特点采用不同的神经元模型进行模拟。最后,在模型的神经动力学上,模型能够及时响应外界刺激。在刺激持续输入时,模型输出呈现出稳定的振荡模式;在特定刺激输入时,模型状态呈现有节奏的极限环状态。

  10. Luminescence of carbon nanotube bulbs

    Institute of Scientific and Technical Information of China (English)

    LI ChuanGang; WU DeHai; WANG KunLin; WEI JinQuan; WEI BingQing; ZHU HongWei; WANG ZhiCheng; LUO JianBin; LIU WenJin; ZHENG MingXin

    2007-01-01

    Carbon nanotube (CNT) bulbs made of decimeter-scale double-walled carbon nanotube (DWCNT) strands and films were fabricated and their luminescence properties, including the lighting efficiency, voltage-current relation and thermal stability were investigated. The results show that the DWCNT bulb has a comparable spectrum of visible light with tungsten bulb and its average efficiency is 40% higher than that of a tungsten filament at the same temperature (1400-2300 K). The nanotube filaments show both resistance and thermal stability over a large temperature region. No obvious damage was found for a nanotube bulb illuminating at 2300 K for more than 24 hours in vacuum.

  11. The rostral migratory stream and olfactory system: smell, disease and slippery cells.

    Science.gov (United States)

    Curtis, Maurice A; Monzo, Hector J; Faull, Richard L M

    2009-01-01

    In the mammalian brain, olfaction is an important sense that is used to detect odors of different kinds that can warn of off food, to produce a mothering instinct in a flock or group of animals, and to warn of danger such as fire or poison. The olfactory system is made up of a long-distance rostral migratory stream that arises from the subventricular zone in the wall of the lateral ventricle, mainly comprises neuroblasts, and stretches all the way through the basal forebrain to terminate in the olfactory bulb. The olfactory bulb receives a constant supply of new neurons that allow ongoing integration of new and different smells, and these are integrated into either the granule cell layer or the periglomerular layer. The continuous turnover of neurons in the olfactory bulb allows us to study the proliferation, migration, and differentiation of neurons and their application in therapies for neurodegenerative diseases. In this chapter, we will examine the notion that the olfactory system might be the route of entry for factors that cause or contribute to neurodegeneration in the central nervous system. We will also discuss the enzymes that may be involved in the addition of polysialic acid to neural cell adhesion molecule, which is vital for allowing the neuroblasts to move through the rostral migratory stream. Finally, we will discuss a possible role of endosialidases for removing polysialic acid from neural cell adhesion molecules, which causes neuroblasts to stop migrating and terminally differentiate into olfactory bulb interneurons.

  12. The experimental observation on the repairing spinal cord injury by olfactory ensheathing cells allograft of different sources

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Objecttive To observe the repaired effect of distinct source olfactory ensheathing cells (OECs) on spinal cord injury (SCI) rats. Methods These OECs were dissociated from olfactory bulb and olfactory mucosa of SD rats and transplanted to the injuried region of spinal cord injury rats. The function of nerve, motor evoked potential of hind legs and the histopathlogical diversities of injuried spinal cord were observed. Results The OECs grafts into the SCI area could survive longer time. The BBB scale, incubat...

  13. Microvasculature of the Olfactory Organ in the Japanese Monkey (Macaca fuscata fuscata)

    Science.gov (United States)

    Okada, Shigenori; Schraufnagel, Dean E.

    2002-06-01

    Olfaction is an important and primitive sense. As its importance has changed with evolution, anatomic adjustments have occurred in its structure and vasculature. Primates are a family of vertebrates that have had to develop their visual system to adapt to the arboreal environment and have evolved from a macrosmatic to a microsmatic species as the optic system has enlarged. This has resulted in anatomic changes of a small but critical area at the base of the brain. This paper describes the three-dimensional vascular anatomy of the olfactory organ of the Japanese monkey (Macaca fuscata fuscata). This is best understood by dividing the organ into three parts: the olfactory tract, olfactory bulb, and olfactory nerves in the nasal mucosa. The bulb can be partitioned into an outer or cortical part and inner or medullary part. The vasculature and tissue were examined grossly and with light microscopy and scanning electron microscopy of vascular corrosion casts. The olfactory tract and bulb were supplied by an arteriole from the anterior cerebral artery on each side. The tract was supplied by capillaries running spirally with a coarse network. At the olfactory bulb, the arteriole ramified into the intracortical and medullary branches that formed capillary networks. The bulbar intracortical capillaries were divided into two layers with different densities and vascular patterns. The capillaries of the superficial layer had a ladder-like pattern. The branches that ran into the medulla of the olfactory bulb were more widely spaced. Twigs from the posterior ethmoidal artery ran along the nerve fiber and formed intra- and extrafascicular networks. Each region of the olfactory organ had characteristic three-dimensional vascular patterns that were related to their cellular architecture.

  14. Evidence for olfactory search in wandering albatross, Diomedea exulans.

    Science.gov (United States)

    Nevitt, Gabrielle A; Losekoot, Marcel; Weimerskirch, Henri

    2008-03-25

    Wandering albatrosses (Diomedea exulans) forage over thousands of square kilometers of open ocean for patchily distributed live prey and carrion. These birds have large olfactory bulbs and respond to fishy-scented odors in at-sea trials, suggesting that olfaction plays a role in natural foraging behavior. With the advent of new, fine-scale tracking technologies, we are beginning to explore how birds track prey in the pelagic environment, and we relate these observations to models of odor transport in natural situations. These models suggest that odors emanating from prey will tend to disperse laterally and downwind of the odor source and acquire an irregular and patchy concentration distribution due to turbulent transport. For a seabird foraging over the ocean, this scenario suggests that olfactory search would be facilitated by crosswind flight to optimize the probability of encountering a plume emanating from a prey item, followed by upwind, zigzag flight to localize the prey. By contrast, birds approaching prey by sight would be expected to fly directly to a prey item, irrespective of wind direction. Using high-precision global positioning system (GPS) loggers in conjunction with stomach temperature recorders to simultaneously monitor feeding events, we confirm these predictions in freely ranging wandering albatrosses. We found that initial olfactory detection was implicated in nearly half (46.8%) of all flown approaches preceding prey-capture events, accounting for 45.5% of total prey mass captured by in-flight foraging. These results offer insights into the sensory basis for area-restricted search at the large spatial scales of the open ocean.

  15. Restless led syndrome model Drosophila melanogaster show successful olfactory learning and 1-day retention of the acquired memory

    Directory of Open Access Journals (Sweden)

    Mika F. Asaba

    2013-09-01

    Full Text Available Restless Legs Syndrome (RLS is a prevalent but poorly understood disorder that ischaracterized by uncontrollable movements during sleep, resulting in sleep disturbance.Olfactory memory in Drosophila melanogaster has proven to be a useful tool for the study ofcognitive deficits caused by sleep disturbances, such as those seen in RLS. A recently generatedDrosophila model of RLS exhibited disturbed sleep patterns similar to those seen in humans withRLS. This research seeks to improve understanding of the relationship between cognitivefunctioning and sleep disturbances in a new model for RLS. Here, we tested learning andmemory in wild type and dBTBD9 mutant flies by Pavlovian olfactory conditioning, duringwhich a shock was paired with one of two odors. Flies were then placed in a T-maze with oneodor on either side, and successful associative learning was recorded when the flies chose theside with the unpaired odor. We hypothesized that due to disrupted sleep patterns, dBTBD9mutant flies would be unable to learn the shock-odor association. However, the current studyreports that the recently generated Drosophila model of RLS shows successful olfactorylearning, despite disturbed sleep patterns, with learning performance levels matching or betterthan wild type flies.

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

    Science.gov (United States)

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

    2014-02-01

    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.

  17. Effect of Atmospheric Press on Wet Bulb Depression

    Science.gov (United States)

    Wheeler, Raymond M.; Stasiak, Michael A.; Lawson, Jamie; Wehkamp, Cara Ann P.; Dixon, Michael A.

    2008-01-01

    Our measurements of wet bulb depression at different pressures matched the modeled adiabatic saturation temps reasonably well. At a dry bulb temp of 25 C, the normal wet bulb temp for 30% RH and 100 kPa is approx.15 C, but this dropped to approx.8 C at 10 kPa. The results suggest that psychrometers need direct calibration at the target pressures or that pressure corrected charts are required. For a given vapour pressure deficit, any moist surfaces, including transpiring plant leaves, will be cooler at lower pressures due to the increased evaporation rates.

  18. Quality Coding by Neural Populations in the Early Olfactory Pathway: Analysis Using Information Theory and Lessons for Artificial Olfactory Systems

    Science.gov (United States)

    Fonollosa, Jordi; Gutierrez-Galvez, Agustin; Marco, Santiago

    2012-01-01

    In this article, we analyze the ability of the early olfactory system to detect and discriminate different odors by means of information theory measurements applied to olfactory bulb activity images. We have studied the role that the diversity and number of receptor neuron types play in encoding chemical information. Our results show that the olfactory receptors of the biological system are low correlated and present good coverage of the input space. The coding capacity of ensembles of olfactory receptors with the same receptive range is maximized when the receptors cover half of the odor input space - a configuration that corresponds to receptors that are not particularly selective. However, the ensemble’s performance slightly increases when mixing uncorrelated receptors of different receptive ranges. Our results confirm that the low correlation between sensors could be more significant than the sensor selectivity for general purpose chemo-sensory systems, whether these are biological or biomimetic. PMID:22719851

  19. Roles of olfactory system dysfunction in depression.

    Science.gov (United States)

    Yuan, Ti-Fei; Slotnick, Burton M

    2014-10-01

    The olfactory system is involved in sensory functions, emotional regulation and memory formation. Olfactory bulbectomy in rat has been employed as an animal model of depression for antidepressant discovery studies for many years. Olfaction is impaired in animals suffering from chronic stress, and patients with clinical depression were reported to have decreased olfactory function. It is believed that the neurobiological bases of depression might include dysfunction in the olfactory system. Further, brain stimulation, including nasal based drug delivery could provide novel therapies for management of depression.

  20. Olfactory ability and object memory in three mouse models of varying body weight, metabolic hormones, and adiposity.

    Science.gov (United States)

    Tucker, Kristal R; Godbey, Steven J; Thiebaud, Nicolas; Fadool, Debra Ann

    2012-10-10

    Physiological and nutritional state can modify sensory ability and perception through hormone signaling. Obesity and related metabolic disorders present a chronic imbalance in hormonal signaling that could impact sensory systems. In the olfactory system, external chemical cues are transduced into electrical signals to encode information. It is becoming evident that this system can also detect internal chemical cues in the form of molecules of energy homeostasis and endocrine hormones, whereby neurons of the olfactory system are modulated to change animal behavior towards olfactory cues. We hypothesized that chronic imbalance in hormonal signaling and energy homeostasis due to obesity would thereby disrupt olfactory behaviors in mice. To test this idea, we utilized three mouse models of varying body weight, metabolic hormones, and visceral adiposity - 1) C57BL6/J mice maintained on a condensed-milk based, moderately high-fat diet (MHF) of 32% fat for 6 months as the diet-induced obesity model, 2) an obesity-resistant, lean line of mice due to a gene-targeted deletion of a voltage-dependent potassium channel (Kv 1.3-null), and 3) a genetic model of obesity as a result of a gene-targeted deletion of the melanocortin 4 receptor (MC4R-null). Diet-induced obese (DIO) mice failed to find a fatty-scented hidden peanut butter cracker, based solely on olfactory cues, any faster than an unscented hidden marble, initially suggesting general anosmia. However, when these DIO mice were challenged to find a sweet-scented hidden chocolate candy, they had no difficulty. Furthermore, DIO mice were able to discriminate between fatty acids that differ by a single double bond and are components of the MHF diet (linoleic and oleic acid) in a habituation-dishabituation paradigm. Obesity-resistant, Kv1.3-null mice exhibited no change in scented object retrieval when placed on the MHF-diet, nor did they perform differently than wild-type mice in parallel habituation-dishabituation paradigms

  1. 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.

  2. Effects of Manganese Exposure on Olfactory Functions in Teenagers: A Pilot Study.

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    Emilia Iannilli

    Full Text Available Long-term exposure to environmental manganese (Mn affects not only attention and neuromotor functions but also olfactory functions of a pre-adolescent local population who have spent their whole life span in contaminated areas. In order to investigate the effect of such exposure at the level of the central nervous system we set up a pilot fMRI experiment pointing at differences of brain activities between a non-exposed population (nine subjects and an exposed one (three subjects. We also measured the volume of the olfactory bulb as well as the identification of standard olfactory stimuli. Our results suggest that young subjects exposed to Mn exhibit a reduction of BOLD signal, subjective odor sensitivity and olfactory bulb volume. Moreover a region of interest SPM analysis showed a specifically reduced response of the limbic system in relation to Mn exposure, suggesting an alteration of the brain network dealing with emotional responses.

  3. Odorant receptors regulate the final glomerular coalescence of olfactory sensory neuron axons.

    Science.gov (United States)

    Rodriguez-Gil, Diego J; Bartel, Dianna L; Jaspers, Austin W; Mobley, Arie S; Imamura, Fumiaki; Greer, Charles A

    2015-05-05

    Odorant receptors (OR) are strongly implicated in coalescence of olfactory sensory neuron (OSN) axons and the formation of olfactory bulb (OB) glomeruli. However, when ORs are first expressed relative to basal cell division and OSN axon extension is unknown. We developed an in vivo fate-mapping strategy that enabled us to follow OSN maturation and axon extension beginning at basal cell division. In parallel, we mapped the molecular development of OSNs beginning at basal cell division, including the onset of OR expression. Our data show that ORs are first expressed around 4 d following basal cell division, 24 h after OSN axons have reached the OB. Over the next 6+ days the OSN axons navigate the OB nerve layer and ultimately coalesce in glomeruli. These data provide a previously unidentified perspective on the role of ORs in homophilic OSN axon adhesion and lead us to propose a new model dividing axon extension into two phases. Phase I is OR-independent and accounts for up to 50% of the time during which axons approach the OB and begin navigating the olfactory nerve layer. Phase II is OR-dependent and concludes as OSN axons coalesce in glomeruli.

  4. Olfactory Assessment of Competitors to the Nest Site: An Experiment on a Passerine Species

    Science.gov (United States)

    Fracasso, Gerardo; Mahr, Katharina; Hoi, Herbert

    2016-01-01

    Since most avian species have been considered anosmic or microsmatic, olfaction and associated behavioural patterns have hardly been investigated. Most importantly, empirical data on avian olfaction is not equally distributed among species. Initial investigations focused on species with relatively big olfactory bulbs because they were thought to have better olfactory capabilities. Hence, in this study we tested the ability of house sparrows (Passer domesticus) to use chemical cues as parameters to estimate nest features. House sparrows are a commonly used model species, but their olfactory capabilities have not been studied so far. We offered two different odours to males and females, namely the scent of mouse urine (Mus musculus domesticus), representing a possible competitor and a threat to eggs and hatchlings, and the odour of hay, representing a familiar and innocuous odour. The experiment was performed at the sunset to simulate a first inspection to new possible roosting or nesting sites. Interestingly, males but not females preferred to spend significantly more time in front of the hay odour, than in front of the scent of mouse urine. Our results strengthen the hypothesis that oscines can not only perceive odours but also use olfaction to assess the environment and estimate nest site quality. PMID:27936093

  5. Development and Organization of the Evolutionarily Conserved Three-Layered Olfactory Cortex

    Science.gov (United States)

    2017-01-01

    Abstract The olfactory cortex is part of the mammalian cerebral cortex together with the neocortex and the hippocampus. It receives direct input from the olfactory bulbs and participates in odor discrimination, association, and learning (Bekkers and Suzuki, 2013). It is thought to be an evolutionarily conserved paleocortex, which shares common characteristics with the three-layered general cortex of reptiles (Aboitiz et al., 2002). The olfactory cortex has been studied as a “simple model” to address sensory processing, though little is known about its precise cell origin, diversity, and identity. While the development and the cellular diversity of the six-layered neocortex are increasingly understood, the olfactory cortex remains poorly documented in these aspects. Here is a review of current knowledge of the development and organization of the olfactory cortex, keeping the analogy with those of the neocortex. The comparison of olfactory cortex and neocortex will allow the opening of evolutionary perspectives on cortical development.

  6. 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

  7. Properties and mechanisms of olfactory learning and memory.

    Science.gov (United States)

    Tong, Michelle T; Peace, Shane T; Cleland, Thomas A

    2014-01-01

    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.

  8. 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.

  9. Closed suction drain with bulb

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/patientinstructions/000039.htm Closed suction drain with bulb To use the sharing features on this page, please enable JavaScript. A closed suction drain is used to remove fluids that build ...

  10. Olfactory ensheathing cells (OECs) degrade neurocan in injured spinal cord by secreting matrix metalloproteinase-2 in a rat contusion model.

    Science.gov (United States)

    Yui, Sho; Fujita, Naoki; Chung, Cheng-Shu; Morita, Maresuke; Nishimura, Ryohei

    2014-11-01

    The mechanism by which olfactory ensheathing cells (OECs) exert their potential to promote functional recovery after transplantation into spinal cord injury (SCI) tissue is not fully understood, but the relevance of matrix metalloproteinases (MMPs) has been suggested. We evaluated the expression of MMPs in OECs in vitro and the MMP secretion by OECs transplanted in injured spinal cord in vivo using a rat SCI model. We also evaluated the degradation of neurocan, which is one of the axon-inhibitory chondroitin sulfate proteoglycans, using SCI model rats. The in vitro results showed that MMP-2 was the dominant MMP expressed by OECs. The in vivo results revealed that transplanted OECs secreted MMP-2 in injured spinal cord and that the expression of neurocan was significantly decreased by the transplantation of OECs. These results suggest that OECs transplanted into injured spinal cord degraded neurocan by secreting MMP-2.

  11. Functional Specialization of Olfactory Glomeruli in a Moth

    Science.gov (United States)

    Hansson, Bill S.; Ljungberg, Hakan; Hallberg, Eric; Lofstedt, Christer

    1992-05-01

    The specific function of the glomerular structures present in the antennal lobes or olfactory bulbs of organisms ranging from insects to humans has been obscure because of limitations in neuronal marking methods. By tracing individual neurons in the moth Agrotis segetum, it was determined that physiologically distinct types of pheromone receptor neurons project axons to different regions of the macroglomerular complex (MGC). Each glomerulus making up the MGC has a specific functional identity, initially processing information about one specific pheromone component. This indicates that, at least through the first stage of synapses, olfactory information moves through labeled lines.

  12. A computational framework for temporal sharpening of stimulus input in the olfactory system.

    Science.gov (United States)

    Zak, Joseph D

    2016-04-01

    The olfactory bulb glomerulus is a dense amalgamation of many unique and interconnected cell types. The mechanisms by which these neurons transform incoming information from the sensory periphery have been extensively studied but often with conflicting findings. A recent study by Carey et al. (J Neurophysiol 113: 3 112-3129, 2015) details the computational framework for parallel modes of temporal refinement of stimulus input to the olfactory system mediated by local neurons within individual glomeruli.

  13. The Isosteroid Alkaloid Imperialine from Bulbs of Fritillaria cirrhosa Mitigates Pulmonary Functional and Structural Impairment and Suppresses Inflammatory Response in a COPD-Like Rat Model

    Science.gov (United States)

    Li, Houcong; Wang, Shu

    2016-01-01

    Chronic obstructive pulmonary disease (COPD) is the third leading cause of death in the world. Present therapies for COPD have limited effect on reducing the progression of COPD and suppressing the inflammatory response in the lung. Bulbs of Fritillaria cirrhosa D. Don (BFC) have been used in many Asian countries for a long time to treat pulmonary diseases, such as cough, expectoration, and asthma. Steroidal alkaloids are the major biological active constituents in BFC, whereby imperialine is one of the important steroidal alkaloids. So far, there are no studies reporting the effect of imperialine on COPD. In this study, we investigated the effect of imperialine on pulmonary function and structure and inflammation in a COPD-like rat model which was induced by the combination of exposure to CS and intratracheal administration of LPS. Our data show that imperialine mitigates pulmonary functional and structural impairment and suppressed inflammatory response in a COPD-like rat model by mediating expression of related cytokines in lung tissues of the COPD-like rats, such as IL-1β, IL-6, IL-8, TNF-α, NF-κB, TGF-β1, MMP-9, and TIMP-1. PMID:27524867

  14. The Isosteroid Alkaloid Imperialine from Bulbs of Fritillaria cirrhosa Mitigates Pulmonary Functional and Structural Impairment and Suppresses Inflammatory Response in a COPD-Like Rat Model

    Directory of Open Access Journals (Sweden)

    Dongdong Wang

    2016-01-01

    Full Text Available Chronic obstructive pulmonary disease (COPD is the third leading cause of death in the world. Present therapies for COPD have limited effect on reducing the progression of COPD and suppressing the inflammatory response in the lung. Bulbs of Fritillaria cirrhosa D. Don (BFC have been used in many Asian countries for a long time to treat pulmonary diseases, such as cough, expectoration, and asthma. Steroidal alkaloids are the major biological active constituents in BFC, whereby imperialine is one of the important steroidal alkaloids. So far, there are no studies reporting the effect of imperialine on COPD. In this study, we investigated the effect of imperialine on pulmonary function and structure and inflammation in a COPD-like rat model which was induced by the combination of exposure to CS and intratracheal administration of LPS. Our data show that imperialine mitigates pulmonary functional and structural impairment and suppressed inflammatory response in a COPD-like rat model by mediating expression of related cytokines in lung tissues of the COPD-like rats, such as IL-1β, IL-6, IL-8, TNF-α, NF-κB, TGF-β1, MMP-9, and TIMP-1.

  15. Destruction of the main olfactory epithelium reduces female sexual behavior and olfactory investigation in female mice.

    Science.gov (United States)

    Keller, Matthieu; Douhard, Quentin; Baum, Michael J; Bakker, Julie

    2006-05-01

    We studied the contribution of the main olfactory system to mate recognition and sexual behavior in female mice. Female mice received an intranasal irrigation of either a zinc sulfate (ZnSO4) solution to destroy the main olfactory epithelium (MOE) or saline (SAL) to serve as control. ZnSO4-treated female mice were no longer able to reliably distinguish between volatile as well as nonvolatile odors from an intact versus a castrated male. Furthermore, sexual behavior in mating tests with a sexually experienced male was significantly reduced in ZnSO4-treated female mice. Vomeronasal function did not seem to be affected by ZnSO4 treatment: nasal application of male urine induced similar levels of Fos protein in the mitral and granule cells of the accessory olfactory bulb (AOB) of ZnSO4 as well as SAL-treated female mice. Likewise, soybean agglutinin staining, which stains the axons of vomeronasal neurons projecting to the glomerular layer of the AOB was similar in ZnSO4-treated female mice compared to SAL-treated female mice. By contrast, a significant reduction of Fos in the main olfactory bulb was observed in ZnSO4-treated females in comparison to SAL-treated animals, confirming a substantial destruction of the MOE. These results show that the MOE is primarily involved in the detection and processing of odors that are used to localize and identify the sex and endocrine status of conspecifics. By contrast, both the main and accessory olfactory systems contribute to female sexual receptivity in female mice.

  16. Contribution of pheromones processed by the main olfactory system to mate recognition in female mammals

    Directory of Open Access Journals (Sweden)

    Micheal J. Baum

    2012-06-01

    Full Text Available Until recently it was widely believed that the ability of female mammals (with the likely exception of women to identify and seek out a male breeding partner relied on the detection of non-volatile male pheromones by the female’s vomeronasal organ and their subsequent processing by a neural circuit that includes the accessory olfactory bulb, vomeronasal amygdala, and hypothalamus. Emperical data are reviewed in this paper that demonstrate the detection of volatile pheromones by the main olfactory epithelium of female mice which, in turn, leads to the activation of a population of glomeruli and abutting mitral cells in the main olfactory bulb (MOB. Anatomical results along with functional neuroanatomical data demonstrate that some of these MOB mitral cells project to the vomeronasal amygdala. These particular MOB mitral cells were selectively activated (i.e., expressed Fos protein by exposure to male as opposed to female urinary volatiles. A similar selectivity to opposite sex urinary volatiles was also seen in mitral cells of the accessory olfactory bulb of female mice. Behavioral data from female mouse, ferret, and human are reviewed that implicate the main olfactory system, in some cases interacting with the accessory olfactory system, in mate recognition.

  17. Hearing light from an incandescent bulb

    Science.gov (United States)

    Zhu, Zheyuan; Du, Li; Zhang, Youtian; Wang, Sihui; Zhou, Huijun; Gao, Wenli

    2015-01-01

    In this paper, we present an interesting experiment to turn the vibratory light from an incandescent light bulb into audible sound. Inspired by research on the photoacoustic effect (PAE) using lasers, we construct a similar device in an undergraduate physics laboratory with everyday articles including light bulbs, glass beakers and soot. Using our device, a distinct sound is detected and analysed experimentally. Particular attention is paid to the attenuation effect of the acoustic signal, which can be explained by modifying the existing theory and using the adiabatic boundary condition according to the incident light source we use. This demonstration is a comprehensive experiment with the combination of sound, light and heat. The modification on the model can help undergraduate students gain an intuitive understanding of different boundary conditions.

  18. Effect of olfactory manganese exposure on anxiety-related behavior in a mouse model of iron overload hemochromatosis.

    Science.gov (United States)

    Ye, Qi; Kim, Jonghan

    2015-07-01

    Manganese in excess promotes unstable emotional behavior. Our previous study showed that olfactory manganese uptake into the brain is altered in Hfe(-/-) mice, a model of iron overload hemochromatosis, suggesting that Hfe deficiency could modify the neurotoxicity of airborne manganese. We determined anxiety-related behavior and monoaminergic protein expression after repeated intranasal instillation of MnCl2 to Hfe(-/-) mice. Compared with manganese-instilled wild-type mice, Hfe(-/-) mice showed decreased manganese accumulation in the cerebellum. Hfe(-/-) mice also exhibited increased anxiety with decreased exploratory activity and elevated dopamine D1 receptor and norepinephrine transporter in the striatum. Moreover, Hfe deficiency attenuated manganese-associated impulsivity and modified the effect of manganese on the expression of tyrosine hydroxylase, vesicular monoamine transporter and serotonin transporter. Together, our data indicate that loss of HFE function alters manganese-associated emotional behavior and further suggest that HFE could be a potential molecular target to alleviate affective disorders induced by manganese inhalation.

  19. Topical Cathelicidin (LL-37) an Innate Immune Peptide Induces Acute Olfactory Epithelium Inflammation in a Mouse Model

    Science.gov (United States)

    Alt, Jeremiah A.; Qin, Xuan; Pulsipher, Abigail; Orb, Quinn; Orlandi, Richard R.; Zhang, Jianxing; Schults, Austin; Jia, Wanjian; Presson, Angela P.; Prestwich, Glenn; Oottamasathien, Siam

    2017-01-01

    Background Cathelicidin (LL-37) is an endogenous innate immune peptide that is elevated in patients with chronic rhinosinusitis (CRS). The role of LL-37 in olfactory epithelium (OE) inflammation remains unknown. We hypothesized that 1) LL-37 topically delivered would elicit profound OE inflammation, and 2) LL-37 induced inflammation is associated with increased infiltration of neutrophils and mast cells. Methods To test our hypothesis we challenged C57BL/6 mice intranasally with increasing concentrations of LL-37. At 24 hours tissues were examined histologically and scored for inflammatory cell infiltrate, edema, and secretory hyperplasia. In separate experiments, fluorescently conjugated LL-37 was instilled and tissues were examined at 0.5 and 24 hours. To test our last hypothesis, we performed tissue myeloperoxidase (MPO) assays for neutrophil activity and immunohistochemistry for tryptase to determine the mean number of mast cells per mm2. Results LL-37 caused increased inflammatory cell infiltrate, edema, and secretory cell hyperplasia of the sinonasal mucosa with higher LL-37 concentrations yielding significantly more inflammatory changes (p < 0.01). Fluorescent LL-37 demonstrated global sinonasal epithelial binding and tissue distribution. Further, higher concentrations of LL-37 led to significantly greater MPO levels with dose-dependent increases in mast cell infiltration (p < 0.01). Conclusions LL-37 has dramatic inflammatory effects in the OE mucosa that is dose-dependent. The observed inflammatory changes in the olfactory mucosa were associated with the infiltration of both neutrophils and mast cells. Our biologic model represents a new model to further investigate the role of LL-37 in OE inflammation. PMID:26346056

  20. 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

  1. Differential characteristics of ketamine self-administration in the olfactory bulbectomy model of depression in male rats.

    Science.gov (United States)

    Babinska, Zuzana; Ruda-Kucerova, Jana

    2017-04-01

    Ketamine has been extensively studied for its antidepressant potential, with promising results in both preclinical and clinical studies. However, concerns regarding its abuse liabilities greatly limit its potential to become an approved treatment for depression. Therefore, a better understanding the risks and benefits of ketamine use in depression is needed. This study aimed to assess the characteristics of operant intravenous (IV) ketamine self-administration and relapse-like behavior in the olfactory bulbectomy (OBX) model of depression in male rats. Twenty-five male Wistar rats were divided randomly into 2 groups; in 1 group the bilateral olfactory bulbectomy was performed, whereas the other group was sham-operated. Intravenous self-administration of ketamine (.5 mg/kg/infusion) was conducted under a fixed ratio 1 schedule of reinforcement. After reaching stable drug intakes, rats then underwent a 14-day period of forced abstinence followed by a drug-free relapse-like session. The forced swim test was conducted before the commencement of the self-administration protocol and on the 1st day of abstinence. Consistent with findings in previous studies on other substances, OBX animals showed increased operant IV ketamine self-administration. In contrast, ketamine-seeking behavior in the OBX group did not differ from sham-operated animals during the relapse-like session, whereas previous studies on other psychostimulants like methamphetamine and cocaine reported increases. Our findings suggest substantially different underlying neuroadaptations between chronic ketamine and psychostimulant exposure. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  2. Identification of G protein α subunits in the main olfactory system and vomeronasal system of the Japanese Striped snake, Elaphe quadrivirgata.

    Science.gov (United States)

    Kondoh, Daisuke; Koshi, Katsuo; Ono, Hisaya K; Sasaki, Kuniaki; Nakamuta, Nobuaki; Taniguchi, Kazuyuki

    2013-01-01

    In the olfactory system, G proteins couple to the olfactory receptors, and G proteins expressed in the main olfactory system and vomeronasal system vary according to animal species. In this study, G protein α subunits expressed in the main olfactory system and vomeronasal system of the snake were identified by immunohistochemistry. In the olfactory epithelium, only anti-Gαolf/s antibody labeled the cilia of the receptor cells. In the vomeronasal epithelium, only anti-Gαo antibody labeled the microvilli of the receptor cells. In the accessory olfactory bulb, anti-Gαo antibody stained the whole glomerular layer. These results suggest that the main olfactory system and the vomeronasal system of the snake express Gαolf and Gαo as G proteins coupling to the olfactory receptors, respectively.

  3. A modification method on runner blades in a Bulb turbine

    Energy Technology Data Exchange (ETDEWEB)

    Yang, W; Wu, Y; Liu, S, E-mail: yang-w03@mails.tsinghua.edu.c [Department of Thermal Engineering, Tsinghua University No.1 Tsinghua Park Haidian District, Beijing, 100084 (China)

    2010-08-15

    In this paper a modification method of the runner blades in a Bulb turbine is proposed, in which the main scale of the runner is maintained. In the modification method the runner blade is expressed by a gather of coordinate points. In order to make the modification simple and efficient, one of the coordinate is fixed and only the angles of the points are changed according to different modification purposes. The Bezier curve is applied to keep the modified blades smooth. For the purpose of verification, the modification method is used in some a prototype Bulb turbine in China. In order to check the modification effectiveness, a three dimensional turbulent computation is carried out through the whole passage including the bulb body, guide vanes, runner and draft tube of a prototype Bulb turbine under its rated operation. An SST k-{omega} turbulence model is used during the flow simulation. The performance prediction of the bulb turbine is conducted by the steady flow simulation. Comparisons of the computational results between the original turbine and a modified one indicate that the modification method is practical and can improve the performance of the bulb turbine.

  4. Aging in the olfactory system.

    Science.gov (United States)

    Mobley, Arie S; Rodriguez-Gil, Diego J; Imamura, Fumiaki; Greer, Charles A

    2014-02-01

    With advancing age, the ability of humans to detect and discriminate odors declines. In light of the rapid progress in analyzing molecular and structural correlates of developing and adult olfactory systems, the paucity of information available on the aged olfactory system is startling. A rich literature documents the decline of olfactory acuity in aged humans, but the underlying cellular and molecular mechanisms are largely unknown. Using animal models, preliminary work is beginning to uncover differences between young and aged rodents that may help address the deficits seen in humans, but many questions remain unanswered. Recent studies of odorant receptor (OR) expression, synaptic organization, adult neurogenesis, and the contribution of cortical representation during aging suggest possible underlying mechanisms and new research directions.

  5. Manganese uptake and distribution in the brain after methyl bromide-induced lesions in the olfactory epithelia.

    Science.gov (United States)

    Thompson, Khristy J; Molina, Ramon M; Donaghey, Thomas; Savaliya, Sandeep; Schwob, James E; Brain, Joseph D

    2011-03-01

    Manganese (Mn) is an essential nutrient with potential neurotoxic effects. Mn deposited in the nose is apparently transported to the brain through anterograde axonal transport, bypassing the blood-brain barrier. However, the role of the olfactory epithelial cells in Mn transport from the nasal cavity to the blood and brain is not well understood. We utilized the methyl bromide (MeBr) lesion model wherein the olfactory epithelium fully regenerates in a time-dependent and cell type-specific manner over the course of 6-8 weeks postinjury. We instilled (54)MnCl(2) intranasally at different recovery periods to study the role of specific olfactory epithelial cell types in Mn transport. (54)MnCl(2) was instilled at 2, 4, 7, 21, and 56 days post-MeBr treatment. (54)Mn concentrations in the blood were measured over the first 4-h period and in the brain and other tissues at 7 days postinstillation. Age-matched control rats were similarly studied at 2 and 56 days. Blood and tissue (54)Mn levels were reduced initially but returned to control values by day 7 post-MeBr exposure, coinciding with the reestablishment of sustentacular cells. Brain (54)Mn levels also decreased but returned to control levels only by 21 days, the period near the completion of neuronal regeneration/bulbar reinnervation. Our data show that Mn transport to the blood and brain temporally correlated with olfactory epithelial regeneration post-MeBr injury. We conclude that (1) sustentacular cells are necessary for Mn transport to the blood and (2) intact axonal projections are required for Mn transport from the nasal cavity to the olfactory bulb and brain.

  6. [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.

  7. Apoptotic death of olfactory sensory neurons in the adult rat.

    Science.gov (United States)

    Deckner, M L; Risling, M; Frisén, J

    1997-01-01

    Olfactory sensory neurons only live for about 1 month in most mammals. It is not fully understood whether the short life span of these neurons is due to necrotic death, or if these cells die by apoptosis. One characteristic of cells undergoing apoptotic cell death is internucleosomal DNA-fragmentation. We have used TdT-mediated dUTP-digoxigenin nick end labeling (TUNEL) to detect cells undergoing DNA-fragmentation in situ. In the intact olfactory epithelium of adult rats a subpopulation of basal immature neuronal progenitor cells, as well as mature olfactory sensory neurons, showed DNA-fragmentation. The number of TUNEL-labeled neurons increased dramatically 1.5 days after transection of the fila olfactoria and declined to control levels by Day 4 after the injury. In order to relate DNA-fragmentation to ultrastructural characteristics of apoptosis we modified the TUNEL-labeling protocol to enable studies of TUNEL-labeled cells in the electron microscope. This confirmed that TUNEL-labeled neurons showed morphological characteristics of apoptosis. The data provide evidence for apoptotic death of neurons in the adult mammalian nervous system. The turnover of olfactory sensory neurons is, at least in part, regulated by apoptosis and disruption of the contact with the olfactory bulb results in massive apoptotic death of neurons in the olfactory epithelium.

  8. Quantitative magnetic resonance imaging evaluation of the olfactory system in Kallmann syndrome: correlation with a clinical smell test.

    Science.gov (United States)

    Koenigkam-Santos, Marcel; Santos, Antonio Carlos; Versiani, Beatriz R; Diniz, Paula Rejane B; Junior, Jorge Elias; de Castro, Margaret

    2011-01-01

    To measure olfactory bulbs and sulci using dedicated magnetic resonance imaging (MRI) sequences and specific measurement tools in Kallmann syndrome (KS) patients with a well-established genotype and phenotype, as well as correlate MRI findings with a clinical smell test. MRI was performed in 21 patients with KS and 16 healthy volunteers; olfactory dysfunction was assessed using the Smell Identification Test (UPSIT), a qualitative suprathreshold olfaction test. Coronal turbo spin echo T2-weighted and volumetric T1-weighted gradient echo sequences were acquired in a 1.5T system. ImageJ software was used to obtain olfactory bulb volumes and olfactory sulcus depths and lengths. Data were analyzed with SPSS 15.0 and the Kappa index was used to evaluate the agreement between the UPSIT and MRI. The UPSIT showed 14 patients with anosmia and 6 with moderate hyposmia. Eighteen patients (85%) presented altered rhinencephalon structures in the MRI. Sixteen patients (76%) presented olfactory bulb aplasia (14/16 bilaterally), and these patients presented a total of 16 aplastic sulci. There was moderate agreement between the MRI quantitative evaluation and the UPSIT (overall Kappa = 0.55), but when considering the presence of aplastic bulbs and anosmia, we found almost perfect agreement (Kappa = 0.87). Three patients had normal rhinencephalon structures, including one with a KAL1 gene mutation. Olfactory bulb and sulcus aplasia were the most common findings in KS patients. We objectively demonstrated agreement between MRI findings and the smell test, especially the presence of bulb aplasia and anosmia. Therefore, our findings help ascertain MRI accuracy in the diagnosis of KS, differentiating patients with hypogonadotropic hypogonadism with an apparently normal or difficult to evaluate sense of smell. Copyright © 2011 S. Karger AG, Basel.

  9. Antidepressant-like effects of nicotine and transcranial magnetic stimulation in the olfactory bulbectomy rat model of depression

    OpenAIRE

    2008-01-01

    In this study, we compared the depression–like symptoms induced by olfactory bulbectomy (OBX) in the two inbred Wistar and Long Evans rat strains. We also analyzed the self-regulated oral intake of nicotine in these strains and the effect of nicotine on the depression-like symptoms of olfactory bulbectomy. Furthermore, we compared the antidepressant-like effects of nicotine on Wistar rats to those of transcranial magnetic stimulation (TMS), which has emerged as a therapeutic alternative for d...

  10. 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.

  11. fMRI study of the role of glutamate NMDA receptor in the olfactory adaptation in rats: Insights into cellular and molecular mechanisms of olfactory adaptation.

    Science.gov (United States)

    Zhao, Fuqiang; Wang, Xiaohai; Zariwala, Hatim A; Uslaner, Jason M; Houghton, Andrea K; Evelhoch, Jeffrey L; Hostetler, Eric; Winkelmann, Christopher T; Hines, Catherine D G

    2017-02-03

    Olfactory adaptation, characterized by attenuation of response to repeated odor stimulations or continuous odor exposure, is an intrinsic feature of olfactory processing. Adaptation can be induced by either "synaptic depression" due to depletion of neurotransmitters, or "enhanced inhibition" onto principle neurons by local inhibitory interneurons in olfactory structures. It is not clear which mechanism plays a major role in olfactory adaptation. More importantly, molecular sources of enhanced inhibition have not been identified. In this study, olfactory responses to either repeated 40-s stimulations with interstimulus intervals (ISI) of 140-s or 30-min, or a single prolonged 200-s stimulus were measured by fMRI in different naïve rats. Olfactory adaptations in the olfactory bulb (OB), anterior olfactory nucleus (AON), and piriform cortex (PC) were observed only with repeated 40-s odor stimulations, and no olfactory adaptations were detected during the prolonged 200-s stimulation. Interestingly, in responses to repeated 40-s odor stimulations in the PC, the first odor stimulation induced positive activations, and odor stimulations under adapted condition induced negative activations. The negative activations suggest that "sparse coding" and "global inhibition" are the characteristics of olfactory processing in PC, and the global inhibition manifests only under an adapted condition, not a naïve condition. Further, we found that these adaptations were NMDA receptor dependent; an NMDA receptor antagonist (MK801) blocked the adaptations. Based on the mechanism that glutamate NMDA receptor plays a role in the inhibition onto principle neurons by interneurons, our data suggest that the olfactory adaptations are caused by enhanced inhibition from interneurons. Combined with the necessity of the interruption of odor stimulation to observe the adaptations, the molecular source for the enhanced inhibition is most likely an increased glutamate release from presynaptic

  12. 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 rot are two of the most important fungal diseases of onion. The taxonomics of several of the n

  13. 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.

  14. Nonoccupational environmental exposure to manganese is linked to deficits in peripheral and central olfactory function.

    Science.gov (United States)

    Guarneros, Marco; Ortiz-Romo, Nahum; Alcaraz-Zubeldia, Mireya; Drucker-Colín, René; Hudson, Robyn

    2013-11-01

    Manganese is of growing concern as a toxic air pollutant. It is readily transported from the olfactory epithelium to the olfactory bulb, and unlike other metals, it is transported transynaptically to structures deep within the brain. However, little is known regarding the possible effect of nonoccupational exposure to manganese on olfactory function. Using the Sniffin' Sticks test battery, we compared the olfactory performance of subjects from a manganese mining district living manganese processing plant, with nonexposed subjects living 50 km from the closest source of exposure (N = 30/group). Groups were matched for age, sex, and schooling, and none had ever worked in mining-related activities. Concentrations of manganese in hair were measured as a biomarker of exposure; exposed subjects had significantly higher concentrations than nonexposed subjects. They were also significantly outperformed by the nonexposed subjects on all olfactory measures (threshold, discrimination, and identification), indicating adverse effects of manganese exposure on a range of olfactory functions, including those involving higher order cognitive processes. This contrasts with previous findings showing adverse peripheral but not central effects on olfactory function of big city air pollution, which mostly consists of toxicants known to affect the olfactory epithelium but with lower transynaptic transport capacity compared with manganese. We conclude that nonoccupational exposure to airborne manganese is associated with decrements in both peripheral and central olfactory function.

  15. Glucuronidation of odorant molecules in the rat olfactory system: activity, expression and age-linked modifications of UDP-glucuronosyltransferase isoforms, UGT1A6 and UGT2A1, and relation to mitral cell activity.

    Science.gov (United States)

    Leclerc, Séverine; Heydel, Jean-Marie; Amossé, Valérie; Gradinaru, Daniela; Cattarelli, Martine; Artur, Yves; Goudonnet, Hervé; Magdalou, Jacques; Netter, Patrick; Pelczar, Hélène; Minn, Alain

    2002-11-15

    The aim of the present study was to examine the glucuronidation of a series of odorant molecules by homogenates prepared either with rat olfactory mucosa, olfactory bulb or brain. Most of the odorant molecules tested were efficiently conjugated by olfactory mucosa, whereas olfactory bulb and brain homogenates displayed lower activities and glucuronidated only a few molecules. Important age-related changes in glucuronidation efficiency were observed in olfactory mucosa and bulb. Therefore, we studied changes in expression of two UDP-glucuronosyltransferase isoforms, UGT1A6 and UGT2A1, in 1-day, 1- and 2-week-, 3-, 12- and 24-month-old rats. UGT1A6 was expressed at the same transcriptional level in the olfactory mucosa, bulb and brain, throughout the life period studied. UGT2A1 mRNA was expressed in both olfactory mucosa and olfactory bulb, in accordance with previous results [Mol. Brain Res. 90 (2001) 83], but UGT2A1 transcriptional level was 400-4000 times higher than that of UGT1A6. Moreover, age-dependent variations in UGT2A1 mRNA expression were observed. As it has been suggested that drug metabolizing enzymes could participate in olfactory function, mitral cell electrical activity was recorded during exposure to different odorant molecules in young, adult and old animals. Age-related changes in the amplitude of response after stimulation with several odorant molecules were observed, and the highest responses were obtained with molecules that were not efficiently glucuronidated by olfactory mucosa. In conclusion, the present work presents new evidence of the involvement of UGT activity in some steps of the olfactory process.

  16. Sharp wave-associated synchronized inputs from the piriform cortex activate olfactory tubercle neurons during slow-wave sleep.

    Science.gov (United States)

    Narikiyo, Kimiya; Manabe, Hiroyuki; Mori, Kensaku

    2014-01-01

    During slow-wave sleep, anterior piriform cortex neurons show highly synchronized discharges that accompany olfactory cortex sharp waves (OC-SPWs). The OC-SPW-related synchronized activity of anterior piriform cortex neurons travel down to the olfactory bulb and is thought to be involved in the reorganization of bulbar neuronal circuitry. However, influences of the OC-SPW-related activity on other regions of the central olfactory system are still unknown. Olfactory tubercle is an area of OC and part of ventral striatum that plays a key role in reward-directed motivational behaviors. In this study, we show that in freely behaving rats, olfactory tubercle receives OC-SPW-associated synchronized inputs during slow-wave sleep. Local field potentials in the olfactory tubercle showed SPW-like activities that were in synchrony with OC-SPWs. Single-unit recordings showed that a subpopulation of olfactory tubercle neurons discharged in synchrony with OC-SPWs. Furthermore, correlation analysis of spike activity of anterior piriform cortex and olfactory tubercle neurons revealed that the discharges of anterior piriform cortex neurons tended to precede those of olfactory tubercle neurons. Current source density analysis in urethane-anesthetized rats indicated that the current sink of the OC-SPW-associated input was located in layer III of the olfactory tubercle. These results indicate that OC-SPW-associated synchronized discharges of piriform cortex neurons travel to the deep layer of the olfactory tubercle and drive discharges of olfactory tubercle neurons. The entrainment of olfactory tubercle neurons in the OC-SPWs suggests that OC-SPWs coordinate reorganization of neuronal circuitry across wide areas of the central olfactory system including olfactory tubercle during slow-wave sleep.

  17. 基于模型试验的灯泡式水轮机轴向水推力研究%Research on Axial Thrust for Bulb Turbine Bases on Model Tests

    Institute of Scientific and Technical Information of China (English)

    李广府; 卢池; 姚丹

    2014-01-01

    In order to do research on the axial thrust of bulb turbines ,a bulb turbine model taken as the research object ,hydraulic axial thrust model test is carried out on test stand for hydraulic machinery .The concept of the ratio Z(axial thrust /driving force)is pro‐posed and the variety regulation of ratio Z with the speed factor ,blade angle and guide vane opening are obtained from the study .The research results indicate that the ratio Z is expressed in ranges in this bulb turbine model and the ratio Z become larger along with the increase in the speed factor and guide vane opening ,while smaller along with the increase in blade angle .%为了研究灯泡贯流式水轮机的轴向水推力问题,以某灯泡贯流式水轮机模型为研究对象,进行了该模型的轴向水推力试验。提出了比值 Z(轴向水推力/水轮机驱动力)这一概念,研究了其随转速因数、叶片角度、导叶开度的变化规律。研究结果表明:该灯泡贯流式水轮机模型比值 Z在某一区间范围,比值 Z随转速因数的增大而增大、随导叶开度的增大而增大、随叶片角度的增大而减小。

  18. How does long-term odor deprivation affect the olfactory capacity of adult mice?

    Directory of Open Access Journals (Sweden)

    Coppola David M

    2010-05-01

    Full Text Available Abstract Background Unilateral naris occlusion (UNO has been the most common method of effecting stimulus deprivation in studies of olfactory plasticity. However, despite the large corpus on the effects of this manipulation, dating back to the 19th century, little is known about its behavioral sequela. Here we report the results of standard olfactory habituation and discrimination studies on adult mice that had undergone perinatal UNO followed by adult contralateral olfactory bulbectomy (bulb-x. Methods The olfactory performance of UNO mice was compared to matched controls that had unilateral bulb-x but open nares. Both habituation and discrimination (operant experiments employed a protocol in which after successful dishabituation or discrimination to dilute individual odors (A = 0.01% isoamyl acetate; B = 0.01% ethyl butyrate; each v/v in mineral oil, mice were challenged with a single odor versus a mixture comparison (A vs. A + B. In a series of tests the volume portion of Odor B in the mixture was systematically decreased until dishabituation or discrimination thresholds were reached. Results For the habituation experiment, UNOs (n = 10 and controls (n = 9 dishabituated to a 10% mixture of Odor B in Odor A after being habituated to A alone, while both groups failed to show differential responding to a 2% mixture of B in A. However, the UNO group's increased investigation durations for the 2% mixture approached significance (p Conclusions Adult mice relying on an olfactory system deprived of odor by naris occlusion from near the time of birth display enhanced olfactory capacity compared to control mice. This counterintuitive result suggests that UNO is neither an absolute method of deprivation nor does it diminish olfactory capabilities. Enhanced olfactory capacity, as observed in the current study, that is a consequence of deprivation, is consistent with recent molecular and physiological evidence that stimulus deprivation triggers

  19. Endothelin uncouples gap junctions in sustentacular cells and olfactory ensheathing cells of the olfactory mucosa.

    Science.gov (United States)

    Le Bourhis, Mikaël; Rimbaud, Stéphanie; Grebert, Denise; Congar, Patrice; Meunier, Nicolas

    2014-09-01

    Several factors modulate the first step of odour detection in the rat olfactory mucosa (OM). Among others, vasoactive peptides such as endothelin might play multifaceted roles in the different OM cells. Like their counterparts in the central nervous system, the olfactory sensory neurons are encompassed by different glial-like non-neuronal OM cells; sustentacular cells (SCs) surround their cell bodies, whereas olfactory ensheathing cells (OECs) wrap their axons. Whereas SCs maintain both the structural and ionic integrity of the OM, OECs assure protection, local blood flow control and guiding of olfactory sensory neuron axons toward the olfactory bulb. We previously showed that these non-neuronal OM cells are particularly responsive to endothelin in vitro. Here, we confirmed that the endothelin system is strongly expressed in the OM using in situ hybridization. We then further explored the effects of endothelin on SCs and OECs using electrophysiological recordings and calcium imaging approaches on both in vitro and ex vivo OM preparations. Endothelin induced both robust calcium signals and gap junction uncoupling in both types of cells. This latter effect was mimicked by carbenoxolone, a known gap junction uncoupling agent. However, although endothelin is known for its antiapoptotic effect in the OM, the uncoupling of gap junctions by carbenoxolone was not sufficient to limit the cellular death induced by serum deprivation in OM primary culture. The functional consequence of the endothelin 1-induced reduction of the gap junctional communication between OM non-neuronal cells thus remains to be elucidated. © 2014 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  20. A cytological and experimental study of the neuropil and primary olfactory afferences to the piriform cortex.

    Science.gov (United States)

    Vargas-Barroso, Víctor; Larriva-Sahd, Jorge

    2013-09-01

    The microscopic organization of the piriform cortex (PC) was studied in normal and experimental material from adult albino rats. In rapid-Golgi specimens a set of collaterals from the lateral olfactory tract (i.e., sublayer Ia) to the neuropil of the Layer II (LII) was identified. Specimens from experimental animals that received electrolytic lesion of the main olfactory bulb three days before sacrificing, were further processed for pre-embedding immunocytochemistry to the enzyme glutamic acid decarboxylase 67 (GAD 67). This novel approach permitted a simultaneous visualization at electron microscopy of both synaptic degeneration and GAD67-immunoreactive (GAD-I) sites. Degenerating and GAD-I synapses were separately found in the neuropil of Layers I and II of the PC. Previously overlooked patches of neuropil were featured in sublayer Ia. These areas consisted of dendritic and axonal processes including four synaptic types. Tridimensional reconstructions from serial thin sections from LI revealed the external appearance of the varicose and tubular dendrites as well as the synaptic terminals therein. The putative source(s) of processes to the neuropil of sublayer Ia is discussed in the context of the internal circuitry of the PC and an alternative model is introduced.

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

    Science.gov (United States)

    Derjean, Dominique; Moussaddy, Aimen; Atallah, Elias; St-Pierre, Melissa; Auclair, François; Chang, Steven; Ren, Xiang; Zielinski, Barbara; Dubuc, Réjean

    2010-01-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Dominique Derjean

    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.

  3. Ultrastructural and histochemical properties of the olfactory system in the japanese jungle crow, Corvus macrorhynchos.

    Science.gov (United States)

    Kondoh, Daisuke; Nashimoto, Mai; Kanayama, Shunsaku; Nakamuta, Nobuaki; Taniguchi, Kazuyuki

    2011-08-01

    Although it has been commonly believed that birds are more dependent on the vision and audition than the olfaction, recent studies indicate that the olfaction of birds is related to the reproductive, homing, and predatory behaviors. In an attempt to reveal the dependence on the olfactory system in crows, we examined the olfactory system of the Japanese jungle crow (Corvus macrorhynchos) by histological, ultrastructural, and lectin histochemical methods. The olfactory epithelium (OE) of the crow occupied remarkably a small area of the nasal cavity (NC) and had the histological and ultrastructural features like other birds. The olfactory bulb (OB) of the crow was remarkably small and did not possess the olfactory ventricle. The left and right halves of the OB were fused in many cases. In the lectin histochemistry, soybean agglutinin (SBA) and Vicia villosa agglutinin (VVA) stained a small number of the receptor cells (RCs) in the OE and the olfactory nerve layer (ONL) and glomerular layer (GL) on the dorsocaudal region of the OB. Phaseolus vulgaris agglutinin-E (PHA-E) stained several RCs in the OE and the ONL and GL on the ventral region of the OB. These results suggest that 1) the crow has less-developed olfactory system than other birds, and 2) the dedicated olfactory receptor cells project their axons to the specific regions of the OB in the crow.

  4. Nanoscale Particulate Matter from Urban Traffic Rapidly Induces Oxidative Stress and Inflammation in Olfactory Epithelium with Concomitant Effects on Brain

    Science.gov (United States)

    Cheng, Hank; Saffari, Arian; Sioutas, Constantinos; Forman, Henry J.; Morgan, Todd E.; Finch, Caleb E.

    2016-01-01

    Background: Rodent models for urban air pollution show consistent induction of inflammatory responses in major brain regions. However, the initial impact of air pollution particulate material on olfactory gateways has not been reported. Objective: We evaluated the olfactory neuroepithelium (OE) and brain regional responses to a nanosized subfraction of urban traffic ultrafine particulate matter (nPM, < 200 nm) in vivo, ex vivo, and in vitro. Methods: Adult mice were exposed to reaerosolized nPM for 5, 20, and 45 cumulative hours over 3 weeks. The OE, the olfactory bulb (OB), the cerebral cortex, and the cerebellum were analyzed for oxidative stress and inflammatory responses. Acute responses of the OE to liquid nPM suspensions were studied with ex vivo and primary OE cultures. Results: After exposure to nPM, the OE and OB had rapid increases of 4-hydroxy-2-nonenal (4-HNE) and 3-nitrotyrosine (3-NT) protein adducts, whereas the cerebral cortex and cerebellum did not respond at any time. All brain regions showed increased levels of tumor necrosis factor-α (TNFα) protein by 45 hr, with earlier induction of TNFα mRNA in OE and OB. These responses corresponded to in vitro OE and mixed glial responses, with rapid induction of nitrite and inducible nitric oxide synthase (iNOS), followed by induction of TNFα. Conclusions: These findings show the differential time course of oxidative stress and inflammatory responses to nPM between the OE and the brain. Slow cumulative transport of inhaled nPM into the brain may contribute to delayed responses of proximal and distal brain regions, with potential input from systemic factors. Citation: Cheng H, Saffari A, Sioutas C, Forman HJ, Morgan TE, Finch CE. 2016. Nanoscale particulate matter from urban traffic rapidly induces oxidative stress and inflammation in olfactory epithelium with concomitant effects on brain. Environ Health Perspect 124:1537–1546; http://dx.doi.org/10.1289/EHP134 PMID:27187980

  5. 中华乌塘鳢嗅觉系统孕酮受体的免疫细胞化学研究%Progesterone receptor immunoreactivities in Bostrichthys sinensis (Lacépède) olfactory system

    Institute of Scientific and Technical Information of China (English)

    赖晓健; 洪万树; 王桂忠; 马细兰; 张其永; 王琼

    2011-01-01

    We evaluated the morphology and structure of the olfactory system in the Chinese black sleeper, Bostrichthys sinensis (Lacepede) using histology. The olfactory system consisted of the olfactory sac, olfactory nerve, and olfactory bulb. The olfactory sac (the rosette) was fusiform in shape and located inside the olfactory chamber, which had two openings that allow water to flow through the rosette as the fish moves. There were 10-16 primary olfactory lamellae radiating from the wall of the olfactory chamber. These lamellae were longitudinally arranged and parallel to each other. The primary olfactory lamellae differed in their height and some possessed secondary olfactory lamellae. Olfactory lamellae were composed of the olfactory epithelium and central core. The olfactory epithelium consisted primarily of ciliated receptor cells, ciliated non-receptor cells, supporting cells, and basal cells. The axons of the primary olfactory receptor neurons in each rosette converged to form a pair olfactory nerves that exceeded 1 cm in length in a 17 cm fish. The paired olfactory nerves extended from the posterior ventral base of each rosette to the ipsilateral olfactory bulb. The two olfactory bulbs, in close contact with the telencephalon, were slightly oval and sessile. Each olfactory bulb consisted of three, roughly distinguishable layers, in order from the surface: (1) the olfactory nerve layer, containing the axons of the olfactory receptor neurons, (2) the glomerular and mitral cell layer, where the axons of the olfactory receptor neurons arborized into glomeruli and the secondary neurons (mitral cells) were scattered around glomeruli, and (3) the granule cell layer, consisting of densely-packed small size cells. Afferent fibers of nerve bundles reached the anterior bulb, spread along the periphery of the bulb and terminated on the dendrites of mitral cells in the glomerular and mitral cell layer. The olfactory nerve layer extended more caudally in the ventral lateral

  6. 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!

  7. Tight temporal coupling between synaptic rewiring of olfactory glomeruli and the emergence of odor-guided behavior in Xenopus tadpoles.

    Science.gov (United States)

    Terni, Beatrice; Pacciolla, Paolo; Masanas, Helena; Gorostiza, Pau; Llobet, Artur

    2017-12-01

    Olfactory sensory neurons (OSNs) are chemoreceptors that establish excitatory synapses within glomeruli of the olfactory bulb. OSNs undergo continuous turnover throughout life, causing the constant replacement of their synaptic contacts. Using Xenopus tadpoles as an experimental system to investigate rewiring of glomerular connectivity, we show that novel OSN synapses can transfer information immediately after formation, mediating olfactory-guided behavior. Tadpoles recover the ability to detect amino acids 4 days after bilateral olfactory nerve transection. Restoration of olfactory-guided behavior depends on the efficient reinsertion of OSNs to the olfactory bulb. Presynaptic terminals of incipient synaptic contacts generate calcium transients in response to odors, triggering long lasting depolarization of olfactory glomeruli. The functionality of reconnected terminals relies on well-defined readily releasable and cytoplasmic vesicle pools. The continuous growth of non-compartmentalized axonal processes provides a vesicle reservoir to nascent release sites, which contrasts to the gradual development of cytoplasmic vesicle pools in conventional excitatory synapses. The immediate availability of fully functional synapses upon formation supports an age-independent contribution of OSNs to the generation of odor maps. © 2017 Wiley Periodicals, Inc.

  8. A Simplified Method to Calculate the Wet Bulb Globe Temperature(WBGT)

    Institute of Scientific and Technical Information of China (English)

    ZHANG Lei; MENG Qing-lin; ZHAO Li-hua; ZHANG Yu-feng

    2009-01-01

    Wet bulb globe temperature(WBGT) is a comprehensive index obtained mainly from three pa-rameters:black globe temperature(Tg),wet bulb temperature(Tw),and dry bulb temperature(Ta).While in field observation and numerical simulation,black globe temperature and wet bulb temperature were not easy to obtain, so WBGT was difficult to measure and calculate directly.In order to solve this problem,air dry bulb temperature, wet bulb temperature,globe temperature,relative humidity,mean air velocity,solar radiation and wet bulb globe temperature were collected during the summer(July)in Guangzhou.Correlation analysis and regression analysis were used to get a simplified method to calculate WBGT.The results showed that dry bulb temperature,relative humidity,solar radiation and WBGT were interrelated to some extent.These three pa-rameters could be used in the simplified method to predict WBGT,and the linear correlation and precision of this model were high.In addition,we used the measured data to verify the simplified method,and the results showed that the error of the calculated value and the measured value was all below 5%,which means the simpli-fied calculating method is feasible and can be used in field observation and simulation research of urban thermal environment.

  9. Temporal Processing in the Olfactory System: Can We See a Smell?

    Science.gov (United States)

    Gire, David H.; Restrepo, Diego; Sejnowski, Terrence J.; Greer, Charles; De Carlos, Juan A.; Lopez-Mascaraque, Laura

    2013-01-01

    Sensory processing circuits in the visual and olfactory systems receive input from complex, rapidly changing environments. Although patterns of light and plumes of odor create different distributions of activity in the retina and olfactory bulb, both structures use what appears on the surface similar temporal coding strategies to convey information to higher areas in the brain. We compare temporal coding in the early stages of the olfactory and visual systems, highlighting recent progress in understanding the role of time in olfactory coding during active sensing by behaving animals. We also examine studies that address the divergent circuit mechanisms that generate temporal codes in the two systems, and find that they provide physiological information directly related to functional questions raised by neuroanatomical studies of Ramon y Cajal over a century ago. Consideration of differences in neural activity in sensory systems contributes to generating new approaches to understand signal processing. PMID:23664611

  10. Temporal processing in the olfactory system: can we see a smell?

    Science.gov (United States)

    Gire, David H; Restrepo, Diego; Sejnowski, Terrence J; Greer, Charles; De Carlos, Juan A; Lopez-Mascaraque, Laura

    2013-05-01

    Sensory processing circuits in the visual and olfactory systems receive input from complex, rapidly changing environments. Although patterns of light and plumes of odor create different distributions of activity in the retina and olfactory bulb, both structures use what appears on the surface similar temporal coding strategies to convey information to higher areas in the brain. We compare temporal coding in the early stages of the olfactory and visual systems, highlighting recent progress in understanding the role of time in olfactory coding during active sensing by behaving animals. We also examine studies that address the divergent circuit mechanisms that generate temporal codes in the two systems, and find that they provide physiological information directly related to functional questions raised by neuroanatomical studies of Ramon y Cajal over a century ago. Consideration of differences in neural activity in sensory systems contributes to generating new approaches to understand signal processing.

  11. Olfactory receptor and neural pathway responsible for highly selective sensing of musk odors.

    Science.gov (United States)

    Shirasu, Mika; Yoshikawa, Keiichi; Takai, Yoshiki; Nakashima, Ai; Takeuchi, Haruki; Sakano, Hitoshi; Touhara, Kazushige

    2014-01-01

    Musk odorants are used widely in cosmetic industries because of their fascinating animalic scent. However, how this aroma is perceived in the mammalian olfactory system remains a great mystery. Here, we show that muscone, one musk odor secreted by various animals from stink glands, activates a few glomeruli clustered in a neuroanatomically unique anteromedial olfactory bulb. The muscone-responsive glomeruli are highly specific to macrocyclic ketones; interestingly, other synthetic musk odorants with nitro or polycyclic moieties or ester bonds activate distinct but nearby glomeruli. Anterodorsal bulbar lesions cause muscone anosmia, suggesting that this region is involved in muscone perception. Finally, we identified the mouse olfactory receptor, MOR215-1, that was a specific muscone receptor expressed by neurons innervating the muscone-responsive anteromedial glomeruli and also the human muscone receptor, OR5AN1. The current study documents the olfactory neural pathway in mice that senses and transmits musk signals from receptor to brain.

  12. Olfactory Reference Syndrome

    Directory of Open Access Journals (Sweden)

    Alper Evrensel

    2015-12-01

    Full Text Available Olfactory reference syndrome is a delusional disorder in which the patient persistently and falsely believes that his or her body emits a foul odor. The disease is considered a variant of somatic type of delusional disorder under the diagnostic systems. Similarities between olfactory reference syndrome and obsessive compulsive disorder have also been noted. The etiopathogenesis of the disorder has not yet been clarified. Antidepressants, antipsychotics and psychotherapy are used in the treatment of this disorder. The aim of this article was to review clinical features, neurobiology, differantial diagnosis, classification problems and treatment of olfactory reference syndrome.

  13. Critical role of GFRα1 in the development and function of the main olfactory system.

    Science.gov (United States)

    Marks, Carolyn; Belluscio, Leonardo; Ibáñez, Carlos F

    2012-11-28

    Glial cell line-derived neurotrophic factor (GDNF) and its receptor GFRα1 are prominently expressed in the olfactory epithelium (OE) and olfactory bulb (OB), but their importance for olfactory system development is completely unknown. We have investigated the consequences of GFRα1 deficiency for mouse olfactory system development and function. In the OE, GFRα1 was expressed in basal precursors, immature olfactory sensory neurons (OSNs), and olfactory ensheathing cells (OECs), but was excluded from mature OSNs. The OE of newborn Gfra1 knock-out mice was thinner and contained fewer OSNs, but more dividing precursors, suggesting deficient neurogenesis. Immature OSN axon bundles were enlarged and associated OECs increased, indicating impaired migration of OECs and OSN axons. In the OB, GFRα1 was expressed in immature OSN axons and OECs of the nerve layer, as well as mitral and tufted cells, but was excluded from GABAergic interneurons. In newborn knock-outs, the nerve layer was dramatically reduced, exhibiting fewer axons and OECs. Bulbs were smaller and presented fewer and disorganized glomeruli and a significant reduction in mitral cells. Numbers of tyrosine hydroxylase-, calbindin-, and calretinin-expressing interneurons were also reduced in newborn mice lacking Gfra1. At birth, the OE and OB of Gdnf knock-out mice displayed comparable phenotypes. Similar deficits were also found in adult heterozygous Gfra1(+/-) mutants, which in addition displayed diminished responses in behavioral tests of olfactory function. We conclude that GFRα1 is critical for the development and function of the main olfactory system, contributing to the development and allocation of all major classes of neurons and glial cells.

  14. Bimodal processing of olfactory information in an amphibian nose: odor responses segregate into a medial and a lateral stream.

    Science.gov (United States)

    Gliem, Sebastian; Syed, Adnan S; Sansone, Alfredo; Kludt, Eugen; Tantalaki, Evangelia; Hassenklöver, Thomas; Korsching, Sigrun I; Manzini, Ivan

    2013-06-01

    In contrast to the single sensory surface present in teleost fishes, several spatially segregated subsystems with distinct molecular and functional characteristics define the mammalian olfactory system. However, the evolutionary steps of that transition remain unknown. Here we analyzed the olfactory system of an early diverging tetrapod, the amphibian Xenopus laevis, and report for the first time the existence of two odor-processing streams, sharply segregated in the main olfactory bulb and partially segregated in the olfactory epithelium of pre-metamorphic larvae. A lateral odor-processing stream is formed by microvillous receptor neurons and is characterized by amino acid responses and Gαo/Gαi as probable signal transducers, whereas a medial stream formed by ciliated receptor neurons is characterized by responses to alcohols, aldehydes, and ketones, and Gαolf/cAMP as probable signal transducers. To reveal candidates for the olfactory receptors underlying these two streams, the spatial distribution of 12 genes from four olfactory receptor gene families was determined. Several class II and some class I odorant receptors (ORs) mimic the spatial distribution observed for the medial stream, whereas a trace amine-associated receptor closely parallels the spatial pattern of the lateral odor-processing stream. Other olfactory receptors (some class I odorant receptors and vomeronasal type 1 receptors) and odor responses (to bile acids, amines) were not lateralized, the latter not even in the olfactory bulb, suggesting an incomplete segregation. Thus, the olfactory system of X. laevis exhibits an intermediate stage of segregation and as such appears well suited to investigate the molecular driving forces behind olfactory regionalization.

  15. 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.

  16. A novel method using intranasal delivery of EdU demonstrates that accessory olfactory ensheathing cells respond to injury by proliferation.

    Science.gov (United States)

    Chehrehasa, Fatemeh; Ekberg, Jenny A K; St John, James A

    2014-03-20

    Olfactory ensheathing cells (OECs) play an important role in the continuous regeneration of the primary olfactory nervous system throughout life and for regeneration of olfactory neurons after injury. While it is known that several individual OEC subpopulations with distinct properties exist in different anatomical locations, it remains unclear how these different subpopulations respond to a major injury. We have examined the proliferation of OECs from one distinct location, the peripheral accessory olfactory nervous system, following large-scale injury (bulbectomy) in mice. We used crosses of two transgenic reporter mouse lines, S100ß-DsRed and OMP-ZsGreen, to visualise OECs, and main/accessory olfactory neurons, respectively. We surgically removed one olfactory bulb including the accessory olfactory bulb to ind