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Sample records for accessory olfactory bulb

  1. Accessory Olfactory Bulb Function is Modulated by Input from the Main Olfactory Epithelium

    OpenAIRE

    Slotnick, Burton; Restrepo, Diego; Schellinck, Heather; Archbold, Georgina; Price, Stephen; Lin, Weihong

    2010-01-01

    While it is now established that sensory neurons in both the main olfactory epithelium and the vomeronasal organ may be activated by both general and pheromonal odorants, it remains unclear what initiates sampling by the VNO. Anterograde transport of wheat germ agglutinin-horseradish peroxidase was used to determine that adequate intranasal syringing with zinc sulfate interrupted all inputs to the main olfactory bulb but left intact those to the accessory olfactory bulb. Adult male treated mi...

  2. Reliable Sex and Strain Discrimination in the Mouse Vomeronasal Organ and Accessory Olfactory Bulb

    OpenAIRE

    Tolokh, Illya I.; Fu, Xiaoyan; Holy, Timothy E.

    2013-01-01

    Animals modulate their courtship and territorial behaviors in response to olfactory cues produced by other animals. In rodents, detecting these cues is the primary role of the accessory olfactory system (AOS). We sought to systematically investigate the natural stimulus coding logic and robustness in neurons of the first two stages of accessory olfactory processing, the vomeronasal organ (VNO) and accessory olfactory bulb (AOB). We show that firing rate responses of just a few well-chosen mou...

  3. Ex Vivo Preparations of the Intact Vomeronasal Organ and Accessory Olfactory Bulb

    OpenAIRE

    Doyle, Wayne I.; Hammen, Gary F.; Meeks, Julian P.

    2014-01-01

    The mouse accessory olfactory system (AOS) is a specialized sensory pathway for detecting nonvolatile social odors, pheromones, and kairomones. The first neural circuit in the AOS pathway, called the accessory olfactory bulb (AOB), plays an important role in establishing sex-typical behaviors such as territorial aggression and mating. This small (

  4. Structure and diversity in mammalian accessory olfactory bulb.

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

    OpenAIRE

    Portillo, Wendy; Unda, Nancy; Camacho, Francisco J.; Sánchez, María; Corona, Rebeca; Arzate, Dulce Ma.; Díaz, Néstor F.; Paredes, Raúl G.

    2012-01-01

    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 da...

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

    OpenAIRE

    Wendy Portillo; Díaz, Néstor F.

    2012-01-01

    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 da...

  7. Activity Regulates Functional Connectivity from the Vomeronasal Organ to the Accessory Olfactory Bulb

    OpenAIRE

    Hovis, Kenneth R.; Ramnath, Rohit; Dahlen, Jeffrey E.; Romanova, Anna L.; LaRocca, Greg; Bier, Mark E.; Urban, Nathaniel N.

    2012-01-01

    The mammalian accessory olfactory system is specialized for the detection of chemicals that identify kin and conspecifics. Vomeronasal sensory neurons (VSNs), residing in the vomeronasal organ, project axons to the accessory olfactory bulb (AOB) where they form synapses with principle neurons, known as mitral cells. The organization of this projection is quite precise and is believed to be essential for appropriate function of this system. However, how this precise connectivity is established...

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

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    Livio eOboti

    2011-09-01

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

  9. Postnatal characterization of cells in the accessory olfactory bulb of wild type and reeler mice

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    Eduardo eMartín-López

    2012-05-01

    Full Text Available Olfaction is the most relevant chemosensory sense of the rodents. General odors are primarily detected by the main olfactory system while most pheromonal signals are received by the accessory olfactory system. The first relay in the brain occurs in the olfactory bulb, which is subdivided in the main and accessory olfactory bulb (MOB/AOB. Given that the cell generation time is different between AOB and MOB, and the cell characterization of AOB remains limited, the goal of this work was first, the definition of the layering of AOB/MOB and second, the establishment of cellular phenotypes in the AOB in a time window corresponding to the early postnatal development. Moreover, since reelin deficiency has been related to layering and olfactory learning deficits, those data were compared with reeler mice. Firstly, we compared the layering between AOB and MOB at early embryonic stages. Then, cell phenotypes were established using specific neuronal and glial markers as well as the reelin adaptor protein Dab1 to analyze differences in both genetic backgrounds. There was no apparent difference in the cell phenotypes among AOB and MOB or between wild type and reeler animals. However, it was outstanding a disruption in the granular cell layer of reeler with respect to wild type mice. In conclusion, the AOB in reelin deficient mice showed similar neuronal and glial cell types being only affected the layering of granular cells.

  10. Convergence of FPR-rs3-expressing neurons in the mouse accessory olfactory bulb.

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    Dietschi, Quentin; Assens, Alexis; Challet, Ludivine; Carleton, Alan; Rodriguez, Ivan

    2013-09-01

    In the mouse, most members of the FPR receptor family are expressed by vomeronasal sensory neurons. The neural circuitry corresponding to this class of chemical sensors is unknown. Taking advantage of the presence of FPR-rs3 on both vomeronasal dendrites and axonal fibers, we visualized the distribution of sensory cells expressing this member of the FPR family, and their corresponding axonal projections in the olfactory bulb. We found a rostrocaudal gradient of receptor choice frequency in the vomeronasal sensory neuroepithelium, and observed a convergence of FPR-rs3 axons into multiple, linked and deeply located glomeruli. These were homogenously innervated, and spatially restricted to the basal portion of the rostral accessory olfactory bulb. This organization, reminiscent of the one that characterizes axonal projections of V1R-expressing neurons, supports a role played by these receptors in the perception of semiochemicals. PMID:23664818

  11. Reliable sex and strain discrimination in the mouse vomeronasal organ and accessory olfactory bulb.

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    Tolokh, Illya I; Fu, Xiaoyan; Holy, Timothy E

    2013-08-21

    Animals modulate their courtship and territorial behaviors in response to olfactory cues produced by other animals. In rodents, detecting these cues is the primary role of the accessory olfactory system (AOS). We sought to systematically investigate the natural stimulus coding logic and robustness in neurons of the first two stages of accessory olfactory processing, the vomeronasal organ (VNO) and accessory olfactory bulb (AOB). We show that firing rate responses of just a few well-chosen mouse VNO or AOB neurons can be used to reliably encode both sex and strain of other mice from cues contained in urine. Additionally, we show that this population code can generalize to new concentrations of stimuli and appears to represent stimulus identity in terms of diverging paths in coding space. Together, the results indicate that firing rate code on the temporal order of seconds is sufficient for accurate classification of pheromonal patterns at different concentrations and may be used by AOS neural circuitry to discriminate among naturally occurring urine stimuli. PMID:23966710

  12. 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].

  13. Ex vivo preparations of the intact vomeronasal organ and accessory olfactory bulb.

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    Doyle, Wayne I; Hammen, Gary F; Meeks, Julian P

    2014-01-01

    The mouse accessory olfactory system (AOS) is a specialized sensory pathway for detecting nonvolatile social odors, pheromones, and kairomones. The first neural circuit in the AOS pathway, called the accessory olfactory bulb (AOB), plays an important role in establishing sex-typical behaviors such as territorial aggression and mating. This small (organization of this system presents unique opportunities for recording from large portions of the circuit simultaneously, investigation of sensory processing in the AOB remains challenging, largely due to its experimentally disadvantageous location in the brain. Here, we demonstrate a multi-stage dissection that removes the intact AOB inside a single hemisphere of the anterior mouse skull, leaving connections to both the peripheral vomeronasal sensory neurons (VSNs) and local neuronal circuitry intact. The procedure exposes the AOB surface to direct visual inspection, facilitating electrophysiological and optical recordings from AOB circuit elements in the absence of anesthetics. Upon inserting a thin cannula into the vomeronasal organ (VNO), which houses the VSNs, one can directly expose the periphery to social odors and pheromones while recording downstream activity in the AOB. This procedure enables controlled inquiries into AOS information processing, which can shed light on mechanisms linking pheromone exposure to changes in behavior. PMID:25145699

  14. 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

  15. In-vivo Vomeronasal Stimulation Reveals Sensory Encoding of Conspecific and Allospecific Cues by the Mouse Accessory Olfactory Bulb

    OpenAIRE

    Dulac, Catherine; Ben-Shaul, Yoram; Katz, Lawrence C.; Mooney, Richard

    2010-01-01

    The rodent vomeronasal system plays a critical role in mediating pheromone-evoked social and sexual behaviors. Recent studies of the anatomical and molecular architecture of the vomeronasal organ (VNO) and of its synaptic target, the accessory olfactory bulb (AOB), have suggested that unique features underlie vomeronasal sensory processing. However, the neuronal representation of pheromonal information leading to specific behavioral and endocrine responses has remained largely unexplored due ...

  16. 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.

  17. Paced-mating increases the number of adult new born cells in the internal cellular (granular layer of the accessory olfactory bulb.

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    Rebeca Corona

    Full Text Available The continuous production and addition of new neurons during life in the olfactory bulb is well accepted and has been extensively studied in rodents. This process could allow the animals to adapt to a changing environment. Olfactory neurogenesis begins in the subventricular zone where stem cells proliferate and give rise to young undifferentiated neuroblasts that migrate along the rostral migratory stream to the olfactory bulb (OB. Olfaction is crucial for the expression of sexual behavior in rodents. In female rats, the ability to control the rate of sexual interactions (pacing has important physiological and behavioral consequences. In the present experiment we evaluated if pacing behavior modifies the rate of new cells that reach the main and accessory olfactory bulb. The BrdU marker was injected before and after different behavioral tests which included: females placed in a mating cage (control, females allowed to pace the sexual interaction, females that mated but were not able to control the rate of the sexual interaction and females exposed to a sexually active male. Subjects were sacrificed fifteen days after the behavioral test. We observed a significant increase in the density of BrdU positive cells in the internal cellular layer of the accessory olfactory bulb when females paced the sexual interaction in comparison to the other 3 groups. No differences in the cell density in the main olfactory bulb were found. These results suggest that pacing behavior promotes an increase in density of the new cells in the accessory olfactory bulb.

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

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    Kahan, Anat; Ben-Shaul, Yoram

    2016-03-01

    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. PMID:26938460

  19. 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.

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

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    Victor eVargas-Barroso

    2016-01-01

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

  1. Sexual stimulation increases the survival of new cells in the accessory olfactory bulb of the male rat.

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    Nancy M Unda

    2016-03-01

    Full Text Available Sexual behavior in rodents is modulated by the olfactory system. The olfactory bulb (OB is a structure that undergoes continues neurogenesis in adulthood. We have previously shown that 15 days after males rats pace the sexual interaction and ejaculate 1 or 3 times, there is an increase in the density of new cells that reach the accessory olfactory bulb (AOB. The aim of the present study was to evaluate if sexual behavior in male rats increases the density of new neurons that survive 45 days after sexual behavior in the AOB and in the main OB (MOB. Male rats were randomly divided in four groups: 1 Control (Ctr, males without sexual interaction; 2 Exposed (Exp, males only exposed to a sexually receptive female; 3 No pacing (NP, males that mated in conditions in which the female paced the sexual interaction; 4 One ejaculation (1E, males that paced the sexual interaction with a receptive female and ejaculated once; and 5 Three ejaculations (3E, males that paced the sexual interaction and were allowed to ejaculate three times. All males were injected with the DNA synthesis marker 5-bromo-2-deoxyuridine (BrdU, and were tested in one of the above conditions. 45 days later they were sacrificed, and the OBs were processed to identify new cells and evaluate if they had differentiated into neurons. Our data indicate that males that ejaculated 3 times showed an increase in the density of new cells that survive in the posterior part of the granular cell layer of the AOB and have more new neurons that the control group. However, no significant differences were found in the percentage of new cells that differentiate into neurons. No significant increase in the density of new cells was observed in the MOB. Our data show that pacing the sexual interaction until 3 ejaculations increases the density of new cells and neurons in the granular layer of the AOB, confirming that sexual behavior induces long-lasting plastic changes in the OB.

  2. A morphological study of the vomeronasal organ and the accessory olfactory bulb in the Korean roe deer, Capreolus pygargus.

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    Park, Changnam; Ahn, Meejung; Lee, Jae-Yuk; Lee, Sang; Yun, Youngmin; Lim, Yoon-Kyu; Taniguchi, Kazumi; Shin, Taekyun

    2014-01-01

    The vomeronasal organ (VNO) and accessory olfactory bulb (AOB) of the Korean roe deer (Capreolus pygargus) were studied histologically to evaluate their morphological characteristics. Grossly, the VNO, encased by cartilage, has a paired tubular structure with a caudal blind end and a rostral connection through incisive ducts on the hard palate. In the VNO, the vomeronasal sensory epithelium (VSE) consists of galectin-3-positive supporting cells, protein gene product (PGP) 9.5-positive receptor cells, and basal cells. The vomeronasal respiratory epithelium (VRE) consists of a pseudostratified epithelium. The AOB strata included a vomeronasal nerve layer (VNL), a glomerular layer (GL), a mitral/tufted cell layer, and a granular cell layer. All lectins used in this study, including Bandeiraea simplicifolia agglutinin isolectin B4 (BSI-B4), soybean agglutinin (SBA), Ulex europaeus agglutinin I (UEA-I), and Triticum vulgaris wheat germ agglutinin (WGA), labeled the VSE with varying intensity. In the AOB, both the VNL and the GL reacted with BSI-B4, SBA, and WGA with varying intensity, but not with UEA-I. This is the first morphological study of the VNO and AOB of the Korean roe deer, which are similar to those of goats. PMID:24055195

  3. Three-dimensional reconstruction of electron micrographs reveals intrabulbar circuit differences between accessory and main olfactory bulbs

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    Keiko eMoriya-Ito

    2013-04-01

    Full Text Available Three-dimensional (3D reconstruction of synaptic arrangement on a particular dendrite provides essential information regarding neuronal properties and neural microcircuits. Unconventional synapses are particularly good candidates for such steric attribution. In main and accessory olfactory bulbs (MOBs and AOBs, there are dendrodendritic reciprocal synapses (RSs between excitatory projection neurons and inhibitory interneurons. Although the fine structure and configuration of these synapses have been investigated in MOB, their characteristics in AOB were unknown. In this study, we performed 3D AOB reconstruction using serial section transmission electron microscopy. We found numerous RSs on primary dendrites from glomeruli to mitral/tufted (MT cell somas. These synapses formed between dendritic shafts of MT cells and large dendritic spines, or so-called gemmules, of granule (Gr cells. This indicates that chemical signals received by a glomerulus are regulated in the primary dendrite of an MT cell before reaching the AOB. In MOB, RSs are located on secondary dendrites and act as lateral and self-inhibiting following mitral cell depolarization. Our results indicate that AOB intrabulbar microcircuitry is quite different from that in the MOB.

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

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    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. PMID:23696538

  5. Adult Olfactory Bulb Neurogenesis.

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    Lledo, Pierre-Marie; Valley, Matt

    2016-01-01

    Most organisms use their olfactory system to detect and analyze chemical cues from the external world to guide essential behaviors. From worms to vertebrates, chemicals are detected by odorant receptors expressed by olfactory sensory neurons, which in vertebrates send an axon to the primary processing center called the olfactory bulb (OB). Within the OB, sensory neurons form excitatory synapses with projection neurons and with inhibitory interneurons. Thus, because of complex synaptic interactions, the output of a given projection neuron is determined not only by the sensory input, but also by the activity of local inhibitory interneurons that are regenerated throughout life in the process of adult neurogenesis. Herein, we discuss how it is optimized and why. PMID:27235474

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

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    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.

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

    Directory of Open Access Journals (Sweden)

    Guy eShpak

    2015-01-01

    Full Text Available Social 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 by the sensory neurons of the main olfactory epithelium and the vomeronasal organ. These neurons then convey sensory information to the main (MOB and accessory (AOB olfactory bulbs, respectively, where they synapse upon mitral cells that project to higher brain areas. Yet, the functional difference between these two chemosensory systems remains unclear. We have previously shown that MOB and AOB mitral cells exhibit very distinct intrinsic biophysical properties leading to different types of information processing. Specifically, we found that unlike MOB mitral cells, AOB neurons display persistent firing responses to strong stimuli. These prolonged responses are mediated by long-lasting calcium-activated non-selective cationic current (Ican. In the current study we further examined the firing characteristics of these cells and their modulation by several neuromodulators. We found that AOB mitral cells display transient depolarizing afterpotentials (DAPs following moderate firing. These DAPs are not found in MOB mitral cells that show instead robust hyperpolarizing afterpotentials. Unlike Ican, the DAPs of AOB mitral cells are activated by low levels of intracellular calcium and are relatively insensitive to flufenamic acid. Moreover, the cholinergic agonist carbachol exerts opposite effects on the persistent firing and DAPs of AOB mitral cells. We conclude that these phenomena are mediated by distinct biophysical mechanisms that may serve to mediate different types of information processing in the AOB at distinct brain states.

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

    Science.gov (United States)

    Shpak, Guy; Zylbertal, Asaph; Wagner, Shlomo

    2014-01-01

    Social 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 by the sensory neurons of the main olfactory epithelium and the vomeronasal organ. These neurons then convey sensory information to the main (MOB) and accessory (AOB) olfactory bulbs, respectively, where they synapse upon mitral cells that project to higher brain areas. Yet, the functional difference between these two chemosensory systems remains unclear. We have previously shown that MOB and AOB mitral cells exhibit very distinct intrinsic biophysical properties leading to different types of information processing. Specifically, we found that unlike MOB mitral cells, AOB neurons display persistent firing responses to strong stimuli. These prolonged responses are mediated by long-lasting calcium-activated non-selective cationic current (Ican). In the current study we further examined the firing characteristics of these cells and their modulation by several neuromodulators. We found that AOB mitral cells display transient depolarizing afterpotentials (DAPs) following moderate firing. These DAPs are not found in MOB mitral cells that show instead robust hyperpolarizing afterpotentials. Unlike Ican, the DAPs of AOB mitral cells are activated by low levels of intracellular calcium and are relatively insensitive to flufenamic acid. Moreover, the cholinergic agonist carbachol exerts opposite effects on the persistent firing and DAPs of AOB mitral cells. We conclude that these phenomena are mediated by distinct biophysical mechanisms that may serve to mediate different types of information processing in the AOB at distinct brain states. PMID:25642164

  9. Histological Structure of the Vomeronasal Organ and Accessory Olfactory Bulb of Myospalax Cansus and Microtus oeconomus%甘肃鼢鼠与根田鼠的犁鼻器和副嗅球结构研究

    Institute of Scientific and Technical Information of China (English)

    王茁; 张淑慧

    2012-01-01

    为了探讨地下鼠犁鼻系统与地面鼠的差异及其与地面鼠嗅觉功能相适应的特点,用组织学方法对甘肃鼢鼠(Myospalax cansus)与根田鼠(Microtus oeconomus)的副嗅球和犁鼻器结构并进行了差异性研究.结果表明,2种鼠的犁鼻器均位于鼻腔前端鼻中隔基部两侧,呈管状;甘肃鼢鼠犁鼻上皮厚度、副嗅球颗粒细胞和僧帽细胞带宽比根田鼠发达;甘肃鼢鼠犁鼻器、副嗅球的性二型分化比根田鼠显著.2种鼠各自犁鼻器和副嗅球的形态有一定的对应关系,甘肃鼢鼠犁鼻上皮、副嗅球厚而短;根田鼠犁鼻上皮、副嗅球薄而长.这种对应关系可能与犁鼻器和副嗅球之间存在着神经投射有关.%In order to explore the difference in the vomeronasal organs and olfactory functions of subterranean rats and ground rats, the histological and immunohistochemistrical methods were used to study the structure of the accessory olfactory bulb and vomeronasal organ in M. cansus and M. oeconomus. The vomeronasal organs of both rats are in the inboard wall of vomeronasal tube, while outside wall protrudes to the central cave slightly, which is pseudostratified epithelium, and its base is bone marrow of a triangle. The vomeronasal epidermis thickness and Ihe band width of accessory olfactory bulb granular cells and mitral cells in M. cansus are well developed than that of M. oeconomus. Compared with the M. oeconomus, the sexually dimorphic of accessory olfactory bulb and vomeronasal organ in M. cansus are significant. There is a certain corresponding relationship between the morphology of accessory olfactory bulb and vomeronasal organ. The vomeronasal epidermis and accessory olfactory bulb of M. cansus are thick and short, while that of M. oecoiwmus are thin and long. The possible reason of this corresponding relationship is related to the nerve projection between these two structures.

  10. Neuronal organization of olfactory bulb circuits

    OpenAIRE

    Shin eNagayama; Ryota eHomma; Fumiaki eImamura

    2014-01-01

    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...

  11. 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

  12. Centrifugal innervation of the mammalian olfactory bulb.

    Science.gov (United States)

    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.

  13. 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...

  14. 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.

  15. Neuronal organization of olfactory bulb circuits

    Directory of Open Access Journals (Sweden)

    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.

  16. Modeling the Olfactory Bulb - Coupled Nonlinear Oscillators

    OpenAIRE

    Li, Zhaoping; Hopfield, J J

    1989-01-01

    The olfactory bulb of mammals aids in the discrimination of odors. A mathematical model based on the bulbar anatomy and electrophysiology is described. Simulations produce a 35-60 Hz modulated activity coherent across the bulb, mimicing the observed field potentials. The decision states (for the odor information) here can be thought of as stable cycles, rather than point stable states typical of simpler neuro-computing models. Analysis and simulations show that a group of...

  17. Olfactory bulb encoding during learning under anaesthesia

    Directory of Open Access Journals (Sweden)

    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

  18. Olfactory bulb encoding during learning under anesthesia

    Science.gov (United States)

    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

  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. 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.

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

    Science.gov (United States)

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

    2010-01-01

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

  2. Topographical representation of odor hedonics in the olfactory bulb.

    Science.gov (United States)

    Kermen, Florence; Midroit, Maëllie; Kuczewski, Nicola; Forest, Jérémy; Thévenet, Marc; Sacquet, Joëlle; Benetollo, Claire; Richard, Marion; Didier, Anne; Mandairon, Nathalie

    2016-07-01

    Hedonic value is a dominant aspect of olfactory perception. Using optogenetic manipulation in freely behaving mice paired with immediate early gene mapping, we demonstrate that hedonic information is represented along the antero-posterior axis of the ventral olfactory bulb. Using this representation, we show that the degree of attractiveness of odors can be bidirectionally modulated by local manipulation of the olfactory bulb's neural networks in freely behaving mice. PMID:27273767

  3. 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.

  4. A direct main olfactory bulb projection to the ‘vomeronasal’ amygdala in female mice selectively responds to volatile pheromones from males

    OpenAIRE

    Kang, Ningdong; Baum, Michael J.; Cherry, James A.

    2009-01-01

    The main olfactory system, like the accessory olfactory system, responds to pheromones involved in social communication. Whereas pheromones detected by the accessory system are transmitted to the hypothalamus via the medial (‘vomeronasal’) amygdala, the pathway by which pheromones are detected and transmitted by the main system is not well understood. We examined in female mice whether a direct projection from mitral/tufted (M/T) cells in the main olfactory bulb (MOB) to the medial amygdala e...

  5. 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…

  6. 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. PMID:25704808

  7. 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.

  8. 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.

  9. 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.

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

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    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.

  11. 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.

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

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    Matthieu eKELLER

    2012-09-01

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

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

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    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.

  15. Either main or accessory olfactory system signaling can mediate the rewarding effects of estrous female chemosignals in sexually naive male mice.

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    Korzan, Wayne J; Freamat, Mihael; Johnson, Adam G; Cherry, James A; Baum, Michael J

    2013-10-01

    A long-held view has been that interest of male mice in female body odors reflects an activation of reward circuits in the male brain following their detection by the vomeronasal organ (VNO) and processing via the accessory olfactory system. We found that adult, sexually naive male mice acquired a conditioned place preference (CPP) after repeatedly receiving estrous female urine on the nose and being placed in an initially nonpreferred chamber with soiled estrous bedding on the floor. CPP was not acquired in control mice that received saline on the nose before being placed in a nonpreferred chamber with clean bedding. Robust acquisition of a CPP using estrous female odors as the reward persisted in separate groups of mice in which VNO-accessory olfactory function was disrupted by bilateral lesioning of the accessory olfactory bulb (AOB) or in which main olfactory function was disrupted by zinc sulfate lesions of the main olfactory epithelium (MOE). By contrast, no CPP was acquired for estrous odors in males that received combined AOB and MOE lesions. Either the main or the accessory olfactory system suffices to mediate the rewarding effects of estrous female odors in the male mouse, even in the absence of prior mating experience. The main olfactory system is part of the circuitry that responds to chemosignals involved in motivated behavior, a role that may be particularly important for humans who lack a functional accessory olfactory system. PMID:23978150

  16. 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.

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

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    Max L Fletcher

    2012-03-01

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

  18. Serotonin increases synaptic activity in olfactory bulb glomeruli.

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

    2016-03-01

    Serotoninergic fibers densely innervate olfactory bulb glomeruli, the first sites of synaptic integration in the olfactory system. Acting through 5HT2A receptors, serotonin (5HT) directly excites external tufted cells (ETCs), key excitatory glomerular neurons, and depolarizes some mitral cells (MCs), the olfactory bulb's main output neurons. We further investigated 5HT action on MCs and determined its effects on the two major classes of glomerular interneurons: GABAergic/dopaminergic short axon cells (SACs) and GABAergic periglomerular cells (PGCs). In SACs, 5HT evoked a depolarizing current mediated by 5HT2C receptors but did not significantly impact spike rate. 5HT had no measurable direct effect in PGCs. Serotonin increased spontaneous excitatory and inhibitory postsynaptic currents (sEPSCs and sIPSCs) in PGCs and SACs. Increased sEPSCs were mediated by 5HT2A receptors, suggesting that they are primarily due to enhanced excitatory drive from ETCs. Increased sIPSCs resulted from elevated excitatory drive onto GABAergic interneurons and augmented GABA release from SACs. Serotonin-mediated GABA release from SACs was action potential independent and significantly increased miniature IPSC frequency in glomerular neurons. When focally applied to a glomerulus, 5HT increased MC spontaneous firing greater than twofold but did not increase olfactory nerve-evoked responses. Taken together, 5HT modulates glomerular network activity in several ways: 1) it increases ETC-mediated feed-forward excitation onto MCs, SACs, and PGCs; 2) it increases inhibition of glomerular interneurons; 3) it directly triggers action potential-independent GABA release from SACs; and 4) these network actions increase spontaneous MC firing without enhancing responses to suprathreshold sensory input. This may enhance MC sensitivity while maintaining dynamic range. PMID:26655822

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

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    James C Walton

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

  20. Adult neurogenesis restores dopaminergic neuronal loss in the olfactory bulb.

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    Lazarini, Françoise; Gabellec, Marie-Madeleine; Moigneu, Carine; de Chaumont, Fabrice; Olivo-Marin, Jean-Christophe; Lledo, Pierre-Marie

    2014-10-22

    Subventricular zone (SVZ) neurogenesis continuously provides new GABA- and dopamine (DA)-containing interneurons for the olfactory bulb (OB) in most adult mammals. DAergic interneurons are located in the glomerular layer (GL) where they participate in the processing of sensory inputs. To examine whether adult neurogenesis might contribute to regeneration after circuit injury in mice, we induce DAergic neuronal loss by injecting 6-hydroxydopamine (6-OHDA) in the dorsal GL or in the right substantia nigra pars compacta. We found that a 6-OHDA treatment of the OB produces olfactory deficits and local inflammation and partially decreases the number of neurons expressing the enzyme tyrosine hydroxylase (TH) near the injected site. Blockade of inflammation by minocycline treatment immediately after the 6-OHDA administration rescued neither TH(+) interneuron number nor the olfactory deficits, suggesting that the olfactory impairments are most likely linked to TH(+) cell death and not to microglial activation. TH(+) interneuron number was restored 1 month later. This rescue resulted at least in part from enhanced recruitment of immature neurons targeting the lesioned GL area. Seven days after 6-OHDA lesion in the OB, we found that the integration of lentivirus-labeled adult-born neurons was biased: newly formed neurons were preferentially incorporated into glomerular circuits of the lesioned area. Behavioral rehabilitation occurs 2 months after lesion. This study establishes a new model into which loss of DAergic cells could be compensated by recruiting newly formed neurons. We propose that adult neurogenesis not only replenishes the population of DAergic bulbar neurons but that it also restores olfactory sensory processing. PMID:25339754

  1. Olfactory bulb volume predicts therapeutic outcome in major depression disorder.

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    Negoias, Simona; Hummel, Thomas; Symmank, Anja; Schellong, Julia; Joraschky, Peter; Croy, Ilona

    2016-06-01

    The volume of the olfactory bulb (OB) is strongly reduced in patients with major depressive disorder (MDD) and this group exhibits markedly decreased olfactory function. It has been suggested that olfactory input is important for maintaining balance in limbic neurocircuits. The aim of our study was to investigate whether reduced OB volume is associated with response to therapy in MDD. Twenty-four inpatients (all women, age 21-49 years, mean 38 ± 10 years SD) with MDD and 36 healthy controls (all women, age 20-52 years, mean 36 ± 10 years SD) underwent structural MRI. OB volume was compared between responders (N = 13) and non-responders (N = 11) to psychotherapy. Retest of OB volume was performed about 6 months after the end of therapy in nine of the patients. Therapy responders exhibited no significant difference in OB volume compared to healthy controls. However, average OB volume of non-responders was 23 % smaller compared to responders (p = .0011). Furthermore, OB volume was correlated with the change of depression severity (r = .46, p = .024). Volume of the OB did not change in the course of therapy. OB volume may be a biological vulnerability factor for the occurrence and/or maintenance of depression, at least in women. PMID:25977168

  2. Biophysical constraints on lateral inhibition in the olfactory bulb.

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    McIntyre, Alexa B R; Cleland, Thomas A

    2016-06-01

    The mitral cells (MCs) of the mammalian olfactory bulb (OB) constitute one of two populations of principal neurons (along with middle/deep tufted cells) that integrate afferent olfactory information with top-down inputs and intrinsic learning and deliver output to downstream olfactory areas. MC activity is regulated in part by inhibition from granule cells, which form reciprocal synapses with MCs along the extents of their lateral dendrites. However, with MC lateral dendrites reaching over 1.5 mm in length in rats, the roles of distal inhibitory synapses pose a quandary. Here, we systematically vary the properties of a MC model to assess the capacity of inhibitory synaptic inputs on lateral dendrites to influence afferent information flow through MCs. Simulations using passivized models with varying dendritic morphologies and synaptic properties demonstrated that, even with unrealistically favorable parameters, passive propagation fails to convey effective inhibitory signals to the soma from distal sources. Additional simulations using an active model exhibiting action potentials, subthreshold oscillations, and a dendritic morphology closely matched to experimental values further confirmed that distal synaptic inputs along the lateral dendrite could not exert physiologically relevant effects on MC spike timing at the soma. Larger synaptic conductances representative of multiple simultaneous inputs were not sufficient to compensate for the decline in signal with distance. Reciprocal synapses on distal MC lateral dendrites may instead serve to maintain a common fast oscillatory clock across the OB by delaying spike propagation within the lateral dendrites themselves. PMID:27009162

  3. Involvement of TRPV1 in the Olfactory Bulb in Rimonabant-Induced Olfactory Discrimination Deficit.

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    Hu, Sherry Shu-Jung

    2016-02-29

    Rimonabant is well recognized as a cannabinoid CB₁ receptor antagonist/inverse agonist. Rimonabant not only antagonizes the effects induced by exogenous cannabinoids and endocannabinoids at CB₁ receptors, it also exerts several pharmacological and behavioral effects independent of CB₁ receptor inactivation. For example, rimonabant can function as a low-potency mixed agonist/antagonist of the transient receptor potential vanilloid receptor 1 (TRPV1). Hence, it is important to explain the underlying mechanisms of the diverse physiological effects induced by rimonabant with caution. Interestingly, CB₁ receptor has recently been suggested to play a role in olfactory functions. Olfaction not only is involved in food intake, visual perception and social interaction, but also is proposed as a putative marker for schizophrenia and autism. Therefore, the present study aimed to investigate whether CB₁ receptor and TRPV1 played a role in olfactory functions. We first used the genetic disruption approach to examine the role of CB₁ receptor in olfactory functions and found that CB₁ knockout mice exhibited olfactory discrimination deficit. However, it is important to point out that these CB₁ knockout mice, despite their normal locomotivity, displayed deficiencies in the olfactory foraging and novel object exploration tasks. These results imply that general exploratory behaviors toward odorant and odorless objects are compromised in CB₁ knockout mice. We next turned to the pharmacological approach to examine the role of CB₁ receptor and TRPV1 in olfactory functions. We found that the short-term administration of rimonabant, injected systemically or directly into the olfactory bulb (OB), impaired olfactory discrimination that was rescued by the TRPV1 antagonist capsazepine (CPZ), via the same route of rimonabant, in wild-type mice. These results suggest that TRPV1 in the OB is involved in rimonabant-induced olfactory discrimination deficit. However, the

  4. Wnt5a controls neurite development in olfactory bulb interneurons

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    Youngshik Choe

    2011-06-01

    Full Text Available Neurons born in the postnatal SVZ (subventricular zone must migrate a great distance before becoming mature interneurons of the OB (olfactory bulb. During migration immature OB neurons maintain an immature morphology until they reach their destination. While the morphological development of these cells must be tightly regulated, the cellular pathways responsible are still largely unknown. Our results show that the non-canonical Wnt pathway induced by Wnt5a is important for the morphological development of OB interneurons both in vitro and in vivo. Additionally, we demonstrate that non-canonical Wnt signalling works in opposition to canonical Wnt signalling in neural precursors from the SVZ in vitro. This represents a novel role for Wnt5a in the development of OB interneurons and suggests that canonical and non-canonical Wnt pathways dynamically oppose each other in the regulation of dendrite maturation.

  5. Rauwolfia vomitoria inhibits olfaction and modifies olfactory bulb cells.

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    Ekong, Moses B; Peter, Aniekan I; Edagha, Innocent A; Ekpene, Ubong U; Friday, Daniel A

    2016-06-01

    The rising cost of orthodox medication has endeared so many to the use of herbs for the management of neurological conditions. Rauwolfia vomitoria (RV) one of such herbs is a rainforest shrub whose parts are used locally in the management of psychiatry and other medical issues. Its usefulness though not in doubt is wrapped with adverse reports as its active constituents depletes brain monoamine and dopamine stores. This motivated this research on the effects of the root bark extract on olfaction and the olfactory bulb of adult Wistar rats. Eighteen adult Wistar rats (220g average) were divided into three groups (n=6); control (placebo), 200mg/kg and 400mg/kg RV root bark extract, respectively. The oral administration lasted for seven days and on day 8, test of olfaction was carried out and the animals immediately anaesthetized with ketamine hydrochloride (i.p.) and perfuse-fixed with 10% neutral buffered formalin. All the brains were processed for histology and immunoreactivity. Results showed loss of body weights and olfaction in the 200mg/kg and 400mg/kg RV groups. There was hypertrophy and atrophy of mitral cells respectively, in the 200mg/kg and 400mg/kg RV groups, while there was hyperplasia of cells in the internal granular and plexiform layers of both groups. There was decreased neuron specific enolase (NSE) and neurofilament (NF) expression in the 200mg/kg RV group, while NF and glial fibrillary acidic protein (GFAP) expression was decreased in the 400mg/kg RV group. However, NSE expression was enhanced in the 400mg/kg group, while GFAP expression was enhanced in the 200mg/kg RV group. These results suggest that these doses of RV affect olfaction and appetite, and stimulate adverse cellular changes in the olfactory bulb.

  6. Osterix is dispensable for the development of the mouse olfactory bulb.

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    Park, Ji-Soo; Park, Geon-Il; Kim, Jung-Eun

    2016-09-01

    Osterix (Osx) has been shown to be an osteoblast-specific transcription factor for bone formation. Recently, it has been reported that Osx is significantly expressed in the mouse olfactory bulb, proving that Osx may play a role in olfactory bulb development, as well as bone development. Here, we studied morphological differences and neuronal cell alterations in the olfactory bulb using an Osx gene-modified mouse model. Although Osx expression was reduced, morphological differences were not observed in the olfactory bulb of Osx heterozygous mice compared with that of wild-type mice. Immunofluorescence using the neuronal marker genes DCX, MAP2, NeuN, and GFAP showed neuronal cell alterations caused by Osx deficiency in the mitral cell layer (MCL) and granule cell layer (GCL) of the olfactory bulb at postnatal stage. The number, morphology, and expression patterns of immature neurons, mature neurons, and astrocytes were identical in both wild-type and Osx heterozygous mice. At the post-embryonic stage, the expression of neuronal markers DCX, Nestin, MAP2, and NeuN were examined in the MCL and GCL of the olfactory bulb in wild-type, Osx heterozygous, and Osx knockout embryos. Both DCX- and Nestin-positive immature neurons, and MAP2- and NeuN-positive mature neurons, revealed a similar expression pattern in all mouse types. These results indicated that olfactory bulb development was not significantly impaired in the absence of Osx. Further study may be necessary to explain the functional properties of the olfactory bulb caused by Osx deficiency. PMID:27449610

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

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    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.

  8. Expression of G proteins in the olfactory receptor neurons of the newt Cynops pyrrhogaster: their unique projection into the olfactory bulbs.

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    Nakada, Tomoaki; Hagino-Yamagishi, Kimiko; Nakanishi, Koki; Yokosuka, Makoto; Saito, Toru R; Toyoda, Fumiyo; Hasunuma, Itaru; Nakakura, Takashi; Kikuyama, Sakae

    2014-10-15

    We analyzed the expression of G protein α subunits and the axonal projection into the brain in the olfactory system of the semiaquatic newt Cynops pyrrhogaster by immunostaining with antibodies against Gαolf and Gαo , by in situ hybridization using probes for Gαolf , Gαo , and Gαi2 , and by neuronal tracing with DiI and DiA. The main olfactory epithelium (OE) consists of two parts, the ventral OE and dorsal OE. In the ventral OE, the Gαolf - and Gαo -expressing neurons are located in the apical and basal zone of the OE, respectively. This zonal expression was similar to that of the OE in the middle cavity of the fully aquatic toad Xenopus laevis. However, the Gαolf - and Gαo -expressing neurons in the newt ventral OE project their axons toward the main olfactory bulb (MOB) and the accessory olfactory bulb (AOB), respectively, whereas in Xenopus, the axons of both neurons project solely toward the MOB. In the dorsal OE of the newt, as in the principal cavity of Xenopus, the majority of the neurons express Gαolf and extend their axons into the MOB. In the vomeronasal organ (VNO), the neurons mostly express Gαo . These neurons and quite a few Gαolf -expressing neurons project their axons toward the AOB. This feature is similar to that in the terrestrial toad Bufo japonicus and is different from that in Xenopus, in which VNO neurons express solely Gαo , although their axons invariably project toward the AOB. We discuss the findings in the light of diversification and evolution of the vertebrate olfactory system. PMID:24771457

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

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    Emre Yaksi

    2007-07-01

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

  10. 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.

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

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    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.

  12. One nose, one brain: contribution of the main and accessory olfactory system to chemosensation

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    Carla eMucignat

    2012-11-01

    Full Text Available The accessory olfactory system is present in most tetrapods. It is involved in the perception of chemical stimuli, being implicated also in the detection of pheromone. However, it is sensitive also to some common odorant molecules, which have no clear implication in intraspecific chemical communication. The accessory olfactory system may complement the main olfactory system, and may contribute different perceptual features to the construction of a unitary representation, which merges the different chemosensory qualities. Crosstalk between the main and accessory olfactory systems occurs at different levels of central processing, in brain areas where the inputs from the two systems converge. Interestingly, centrifugal projections from more caudal brain areas are deeply involved in modulating both main and accessory sensory processing. A high degree of interaction between the two systems may be conceived, and partial overlapping appears to occur in many functions. Therefore, the central chemosensory projections merge inputs from different organs to obtain a complex chemosensory picture.

  13. One nose, one brain: contribution of the main and accessory olfactory system to chemosensation.

    Science.gov (United States)

    Mucignat-Caretta, Carla; Redaelli, Marco; Caretta, Antonio

    2012-01-01

    The accessory olfactory system is present in most tetrapods. It is involved in the perception of chemical stimuli, being implicated also in the detection of pheromones. However, it is sensitive also to some common odorant molecules, which have no clear implication in intraspecific chemical communication. The accessory olfactory system may complement the main olfactory system and may contribute different perceptual features to the construction of a unitary representation, which merges the different chemosensory qualities. Crosstalk between the main and accessory olfactory systems occurs at different levels of central processing, in brain areas where the inputs from the two systems converge. Interestingly, centrifugal projections from more caudal brain areas are deeply involved in modulating both main and accessory sensory processing. A high degree of interaction between the two systems may be conceived and partial overlapping appears to occur in many functions. Therefore, the central chemosensory projections merge inputs from different organs to obtain a complex chemosensory picture. PMID:23162438

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

    Directory of Open Access Journals (Sweden)

    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.

  15. 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.

  16. 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.

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

    OpenAIRE

    Sakamoto, Masayuki; Kageyama, Ryoichiro; Imayoshi, Itaru

    2014-01-01

    The olfactory bulb (OB) is the first central processing center for olfactory information connecting with higher areas in the brain, and this neuronal circuitry mediates a variety of odor-evoked behavioral responses. In the adult mammalian brain, continuous neurogenesis occurs in two restricted regions, the subventricular zone (SVZ) of the lateral ventricle and the hippocampal dentate gyrus. New neurons born in the SVZ migrate through the rostral migratory stream and are integrated into the ne...

  18. 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…

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

    Directory of Open Access Journals (Sweden)

    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.

  20. 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.

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

    Science.gov (United States)

    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.

  2. 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.

  3. α-Synuclein aggregation in the olfactory bulb of middle-aged common marmoset.

    Science.gov (United States)

    Kobayashi, Reona; Takahashi-Fujigasaki, Junko; Shiozawa, Seiji; Hara-Miyauchi, Chikako; Inoue, Takashi; Okano, Hirotaka James; Sasaki, Erika; Okano, Hideyuki

    2016-05-01

    The synaptic protein α-synuclein has been identified as a major component of Lewy bodies, a pathological hallmark of Parkinson's disease (PD). Prior to the formation of Lewy bodies, mislocalization and aggregation of the α-synuclein in brain tissue is frequently observed in various neurodegenerative diseases. Aberrant accumulation and localization of α-synuclein are also observed in the aging human brain, for which reason aging is regarded as a risk factor for neurodegenerative disease. To investigate changes in α-synuclein properties in the aging brain, we compared α-synuclein immunoreactivity in brain tissue of young (2-years-old) and middle-aged (6-years-old) common marmoset (Callithrix jacchus). Our analyses revealed marked changes in α-synuclein immunoreactivity in the olfactory bulb of common marmosets of these age cohorts. Perikaryal α-synuclein aggregations were formed in the olfactory bulb in middle-aged animals. We also observed signals of α-synuclein accumulation in hippocampus in this cohort; however, unlike in the olfactory bulb, hippocampal α-synuclein signals were localized in the synaptic terminals. We did not observe either of these features in younger marmosets, which suggest that aging may play a role in these phenomena. Our results using common marmoset brain corresponded with the observation that the α-synuclein aggregations were first occurred from olfactory bulb in human normal aged and PD brain. Therefore, common marmoset is expected as useful model for α-synuclein pathology. PMID:26643383

  4. 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...

  5. Adult Olfactory Bulb Interneuron Phenotypes Identified by Targeting Embryonic and Postnatal Neural Progenitors.

    Science.gov (United States)

    Figueres-Oñate, Maria; López-Mascaraque, Laura

    2016-01-01

    Neurons are generated during embryonic development and in adulthood, although adult neurogenesis is restricted to two main brain regions, the hippocampus and olfactory bulb. The subventricular zone (SVZ) of the lateral ventricles generates neural stem/progenitor cells that continually provide the olfactory bulb (OB) with new granule or periglomerular neurons, cells that arrive from the SVZ via the rostral migratory stream. The continued neurogenesis and the adequate integration of these newly generated interneurons is essential to maintain homeostasis in the olfactory bulb, where the differentiation of these cells into specific neural cell types is strongly influenced by temporal cues. Therefore, identifying the critical features that control the generation of adult OB interneurons at either pre- or post-natal stages is important to understand the dynamic contribution of neural stem cells. Here, we used in utero and neonatal SVZ electroporation along with a transposase-mediated stable integration plasmid, in order to track interneurons and glial lineages in the OB. These plasmids are valuable tools to study the development of OB interneurons from embryonic and post-natal SVZ progenitors. Accordingly, we examined the location and identity of the adult progeny of embryonic and post-natally transfected progenitors by examining neurochemical markers in the adult OB. These data reveal the different cell types in the olfactory bulb that are generated in function of age and different electroporation conditions. PMID:27242400

  6. Value of MRI olfactory bulb evaluation in the assessment of olfactory dysfunction in Bardet-Biedl syndrome.

    Science.gov (United States)

    Braun, J J; Noblet, V; Kremer, S; Molière, S; Dollfus, H; Marion, V; Goetz, N; Muller, J; Riehm, S

    2016-07-01

    Olfactory bulb (OB) volume evaluation by magnetic resonance imaging (MRI) has been demonstrated to be related to olfactory dysfunction in many different diseases. Olfactory dysfunction is often overlooked in Bardet-Biedl syndrome (BBS) patients and is rarely objectively evaluated by MRI. We present a series of 20 BBS patients with olfactory dysfunction. The OB was evaluated separately and blindly by two radiologists (SR and SM) with 3 Tesla MRI imaging comparatively to 12 normal control subjects by global visual evaluation and by quantitative measurement of OB volume. In the 12 control cases OB visual evaluation was considered as normal in all cases for radiologist (SR) and in 10 cases for radiologist (SM). In the 20 BBS patients, OB visual evaluation was considered as abnormal in 18 cases for SR and in all cases for SM. OB volumetric evaluation for SR and SM in BBS patients was able to provide significant correlation between BBS and olfactory dysfunction. This study indicates that OB volume evaluation by MRI imaging like structural MRI scan for gray matter modifications demonstrates that olfactory dysfunction in BBS patients is a constant and cardinal symptom integrated in a genetical syndrome with peripheral and central olfactory structure alterations. PMID:26586152

  7. 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.

  8. 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.

  9. 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.

  10. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  12. 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.

  13. Mechanisms and benefits of granule cell latency coding in the mouse olfactory bulb

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    Sonya eGiridhar

    2012-06-01

    Full Text Available Inhibitory circuits are critical for shaping odor representations in the olfactory bulb. Individual olfactory bulb granule cells can respond to brief stimulation with extremely long (up to 1000 ms, input-specific latencies that are highly reliable. However, the mechanism and function of this long timescale activity remain unknown. We sought to elucidate the mechanism responsible for long-latency activity, and to understand the impact of widely distributed interneuron latencies on olfactory coding. We used a combination of electrophysiological, optical, and pharmacological techniques to show that long-latency inhibition is driven by late onset synaptic excitation to granule cells. We also provide evidence that tufted cells, which have intrinsic properties that favor longer latency spiking than mitral cells are the major source of this excitation. Using computational modeling, we show that widely distributed interneuron latency can increase the discriminability of similar stimuli. Thus, long-latency inhibition in the olfactory bulb requires a combination of circuit- and cellular-level mechanisms that function to improve stimulus representations.

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

    Science.gov (United States)

    Navarrete, Erika; Ortega-Bernal, Juan Roberto; Trejo-Muñoz, Lucero; Díaz, Georgina; Montúfar-Chaveznava, Rodrigo; Caldelas, Ivette

    2016-01-01

    Experimental evidence indicates that during pre-visual stages of development in mammals, circadian regulation is still not under the control of the light-entrainable hypothalamic pacemaker, raising the possibility that the circadian rhythmicity that occurs during postnatal development is under the control of peripheral oscillators, such as the main olfactory bulb (MOB). We evaluated the outcome of olfactory bulbectomy on the temporal pattern of core body temperature and gross locomotor activity in newborn rabbits. From postnatal day 1 (P1), pups were randomly assigned to one of the following conditions: intact pups (INT), intact pups fed by enteral gavage (INT+ENT), sham operated pups (SHAM), pups with unilateral lesions of the olfactory bulb (OBx-UNI), and pups with bilateral lesions of the olfactory bulb (OBx-BI). At the beginning of the experiment, from P1-8, the animals in all groups were fed at 11:00, from P9-13 the feeding schedule was delayed 6 h (17:00), and finally, from P14-15 the animals were subjected to fasting conditions. The rabbit pups of the INT, INT+ENT, SHAM and OBx-UNI groups exhibited a clear circadian rhythmicity in body temperature and locomotor activity, with a conspicuous anticipatory rise hours prior to the nursing or feeding schedule, which persisted even during fasting conditions. In addition, phase delays in the nursing or feeding schedule induced a clear phase shift in both parameters. In contrast, the OBx-BI group exhibited atypical rhythmicity in both parameters under entrained conditions that altered the anticipatory component, as well as deficient phase control of both rhythms. The present results demonstrate that the expression of circadian rhythmicity at behavioral and physiological levels during early stages of rabbit development largely depends on the integrity of the main olfactory bulb. PMID:27305041

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

    Directory of Open Access Journals (Sweden)

    Erika Navarrete

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

  16. Patterns of olfactory bulb neurogenesis in the adult zebrafish are altered following reversible deafferentation.

    Science.gov (United States)

    Trimpe, Darcy M; Byrd-Jacobs, Christine A

    2016-09-01

    Adult brain plasticity can be investigated using reversible methods that remove afferent innervation but allow return of sensory input. Repeated intranasal irrigation with Triton X-100 in adult zebrafish diminishes innervation to the olfactory bulb, resulting in a number of alterations in bulb structure and function, and cessation of the treatment allows for reinnervation and recovery. Using bromodeoxyuridine, Hu, and caspase-3 immunoreactivity we examined cell proliferation, differentiation, migration, and survival under conditions of acute and chronic deafferentation and reafferentation. Cell proliferation within the olfactory bulb was not influenced by acute or chronic deafferentation or reafferentation, but cell fate (including differentiation, migration, and/or survival of newly formed cells) was affected. We found that chronic deafferentation caused a bilateral increase in the number of newly formed cells that migrated into the bulb, although the amount of cell death of these new cells was significantly increased compared to untreated fish. Reafferentation also increased the number of newly formed cells migrating into both bulbs, suggesting that the deafferentation effect on cell fate was maintained. Reafferentation resulted in a decrease in newly formed cells that became neurons and, although death of newly formed cells was not altered from control levels, survival was reduced in relation to that seen in chronically deafferented fish. The potential effect of age on cell genesis was also examined. While the amount of cell migration into the olfactory bulbs was not affected by fish age, more of the newly formed cells became neurons in older fish. Younger fish displayed more cell death under conditions of chronic deafferentation. In sum, our results show that reversible deafferentation affects several aspects of cell fate, including cell differentiation, migration, and survival, and age of the fish influences the response to deafferentation. PMID:27343831

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

    Science.gov (United States)

    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.

  18. Olfactory bulb units - Activity correlated with inhalation cycles and odor quality.

    Science.gov (United States)

    Macrides, F.; Chorover, S. L.

    1972-01-01

    Single olfactory bulb units were studied in two macrosmatic species of rodents under conditions intended to preserve the cyclical stimulation which normally accompanies nasal breathing. Patterns of unit activity related to the inhalation cycle were observed in all animals, often in the absence of specific stimuli, and could not be explained in simple mechanical terms. Distinctive changes in these patterns occurred in response to certain odors, and were generally independent of changes in the overall firing frequency. These findings indicate that a change in the overall firing frequency of unit discharges is neither a necessary nor sufficient measure of responsiveness to odors in the rodent olfactory bulb, and that stimulus-specific temporal distributions of unit firing may be involved in olfacto-endocrine activities.

  19. The impact of adult neurogenesis on olfactory bulb circuits and computations.

    Science.gov (United States)

    Lepousez, Gabriel; Valley, Matthew T; Lledo, Pierre-Marie

    2013-01-01

    Modern neuroscience has demonstrated how the adult brain has the ability to profoundly remodel its neurons in response to changes in external stimuli or internal states. However, adult brain plasticity, although possible throughout life, remains restricted mostly to subcellular levels rather than affecting the entire cell. New neurons are continuously generated in only a few areas of the adult brain-the olfactory bulb and the dentate gyrus-where they integrate into already functioning circuitry. In these regions, adult neurogenesis adds another dimension of plasticity that either complements or is redundant to the classical molecular and cellular mechanisms of plasticity. This review extracts clues regarding the contribution of adult-born neurons to the different circuits of the olfactory bulb and specifically how new neurons participate in existing computations and enable new computational functions. PMID:23190074

  20. Olfactory bulb proteome dynamics during the progression of sporadic Alzheimer's disease: identification of common and distinct olfactory targets across Alzheimer-related co-pathologies

    OpenAIRE

    Zelaya, María Victoria; Pérez-Valderrama, Estela; de Morentin, Xabier Martínez; Tuñon, Teresa; Ferrer, Isidro; Luquin, María Rosario; Fernandez-Irigoyen, Joaquín; Santamaría, Enrique

    2015-01-01

    Olfactory dysfunction is present in up to 90% of Alzheimer's disease (AD) patients. Although deposition of hyperphosphorylated tau and β-amyloid substrates are present in olfactory areas, the molecular mechanisms associated with decreased smell function are not completely understood. We have applied mass spectrometry-based quantitative proteomics to probe additional molecular disturbances in postmortem olfactory bulbs (OB) dissected from AD cases respect to neurologically intact controls (n=2...

  1. Sexual dimorphism in the human olfactory bulb: females have more neurons and glial cells than males.

    Directory of Open Access Journals (Sweden)

    Ana V Oliveira-Pinto

    Full Text Available Sex differences in the human olfactory function reportedly exist for olfactory sensitivity, odorant identification and memory, and tasks in which odors are rated based on psychological features such as familiarity, intensity, pleasantness, and others. Which might be the neural bases for these behavioral differences? The number of cells in olfactory regions, and especially the number of neurons, may represent a more accurate indicator of the neural machinery than volume or weight, but besides gross volume measures of the human olfactory bulb, no systematic study of sex differences in the absolute number of cells has yet been undertaken. In this work, we investigate a possible sexual dimorphism in the olfactory bulb, by quantifying postmortem material from 7 men and 11 women (ages 55-94 years with the isotropic fractionator, an unbiased and accurate method to estimate absolute cell numbers in brain regions. Female bulbs weighed 0.132 g in average, while male bulbs weighed 0.137 g, a non-significant difference; however, the total number of cells was 16.2 million in females, and 9.2 million in males, a significant difference of 43.2%. The number of neurons in females reached 6.9 million, being no more than 3.5 million in males, a difference of 49.3%. The number of non-neuronal cells also proved higher in women than in men: 9.3 million and 5.7 million, respectively, a significant difference of 38.7%. The same differences remained when corrected for mass. Results demonstrate a sex-related difference in the absolute number of total, neuronal and non-neuronal cells, favoring women by 40-50%. It is conceivable that these differences in quantitative cellularity may have functional impact, albeit difficult to infer how exactly this would be, without knowing the specific circuits cells make. However, the reported advantage of women as compared to men may stimulate future work on sex dimorphism of synaptic microcircuitry in the olfactory bulb.

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

    OpenAIRE

    Roberto Vincis; Samuel Lagier; Dimitri Van De Ville; Ivan Rodriguez; Alan Carleton

    2015-01-01

    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 independ...

  3. Optophysiological analysis of pattern classification strategies in the zebrafish olfactory bulb

    OpenAIRE

    Niessing, Jörn

    2012-01-01

    Classification of overlapping activity patterns is a common problem for sensory systems. For a robust representation of sensory stimuli, neuronal circuits should generalize over input patterns reflecting variations of the same stimulus but separate patterns representing different stimuli, even if they are highly overlapping. In the olfactory bulb (OB), input patterns evoked by related, yet distinct, odors are often highly overlapping but perceived as a different stimulus. Consistent with this...

  4. 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.

  5. Persistent anosmia and olfactory bulb atrophy after mulga (Pseudechis australis) snakebite.

    Science.gov (United States)

    Sethi, Moksh; Cook, Mark; Winkel, Kenneth D

    2016-07-01

    Loss of sense of smell is an intriguing yet under-recognised complication of snakebite. We report olfactory function testing and neuroimaging of the olfactory bulbs in a 30-year-old man with anosmia persisting for more than 1year after mulga (Pseudechis australis) snakebite. This problem was first noted by the patient 1week after being definitely bitten in Queensland, Australia. He had then presented to a regional hospital where his envenomation was considered mild enough to not warrant antivenom administration. A week later the patient noted a reduction of sense of smell, which progressed to complete inability to smell over the ensuing weeks. On clinical review the patient's neurologic and rhinologic examination did not reveal any structural cause for anosmia. Formal olfactory testing was performed using ''sniffin' sticks" and the patient scored 17 on this test, indicating severe hyposmia (functional anosmia 30.3 for men aged 16-35years). MRI of the brain showed no abnormalities. The olfactory bulb volumes were then measured on a volumetric T2-weighted MRI that demonstrated significantly reduced volume of both bulbs, with the right 34.86mm(3) and left 36.25mm(3) (normal volume ⩾58mm(3), 10th centile). The current patient represents a rare instance of a definite, untreated, elapid (mulga snake) envenomation with an intriguing disjunction between the mildness of the systemic features and the severity of the olfactory lesion. It is also unclear if early antivenom use attenuates this condition, and due to the delayed manifestation of the symptoms, awareness of this phenomenon may be lacking amongst physicians. PMID:26896910

  6. Improved spatial accuracy of functional maps in the rat olfactory bulb using supervised machine learning approach.

    Science.gov (United States)

    Murphy, Matthew C; Poplawsky, Alexander J; Vazquez, Alberto L; Chan, Kevin C; Kim, Seong-Gi; Fukuda, Mitsuhiro

    2016-08-15

    Functional MRI (fMRI) is a popular and important tool for noninvasive mapping of neural activity. As fMRI measures the hemodynamic response, the resulting activation maps do not perfectly reflect the underlying neural activity. The purpose of this work was to design a data-driven model to improve the spatial accuracy of fMRI maps in the rat olfactory bulb. This system is an ideal choice for this investigation since the bulb circuit is well characterized, allowing for an accurate definition of activity patterns in order to train the model. We generated models for both cerebral blood volume weighted (CBVw) and blood oxygen level dependent (BOLD) fMRI data. The results indicate that the spatial accuracy of the activation maps is either significantly improved or at worst not significantly different when using the learned models compared to a conventional general linear model approach, particularly for BOLD images and activity patterns involving deep layers of the bulb. Furthermore, the activation maps computed by CBVw and BOLD data show increased agreement when using the learned models, lending more confidence to their accuracy. The models presented here could have an immediate impact on studies of the olfactory bulb, but perhaps more importantly, demonstrate the potential for similar flexible, data-driven models to improve the quality of activation maps calculated using fMRI data. PMID:27236085

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

    Science.gov (United States)

    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. PMID:26211445

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

    Directory of Open Access Journals (Sweden)

    Laura C Manella

    2013-12-01

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

  9. Neuronal pattern separation in the olfactory bulb improves odor discrimination learning

    Science.gov (United States)

    Lagier, Samuel; Begnaud, Frédéric; Rodriguez, Ivan; Carleton, Alan

    2015-01-01

    Neuronal pattern separation is thought to enable the brain to disambiguate sensory stimuli with overlapping features thereby extracting valuable information. In the olfactory system, it remains unknown whether pattern separation acts as a driving force for sensory discrimination and the learning thereof. Here we show that overlapping odor-evoked input patterns to the mouse olfactory bulb (OB) are dynamically reformatted in the network at the timescale of a single breath, giving rise to separated patterns of activity in ensemble of output neurons (mitral/tufted cells; M/T). Strikingly, the extent of pattern separation in M/T assemblies predicts behavioral discrimination performance during the learning phase. Furthermore, exciting or inhibiting GABAergic OB interneurons, using optogenetics or pharmacogenetics, altered pattern separation and thereby odor discrimination learning in a bidirectional way. In conclusion, we propose that the OB network can act as a pattern separator facilitating olfactory stimuli distinction, a process that is sculpted by synaptic inhibition. PMID:26301325

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

    Science.gov (United States)

    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.

  11. 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.

  12. 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.

  13. Neurogenesis drives stimulus decorrelation in a model of the olfactory bulb.

    Directory of Open Access Journals (Sweden)

    Siu-Fai Chow

    Full Text Available The reshaping and decorrelation of similar activity patterns by neuronal networks can enhance their discriminability, storage, and retrieval. How can such networks learn to decorrelate new complex patterns, as they arise in the olfactory system? Using a computational network model for the dominant neural populations of the olfactory bulb we show that fundamental aspects of the adult neurogenesis observed in the olfactory bulb--the persistent addition of new inhibitory granule cells to the network, their activity-dependent survival, and the reciprocal character of their synapses with the principal mitral cells--are sufficient to restructure the network and to alter its encoding of odor stimuli adaptively so as to reduce the correlations between the bulbar representations of similar stimuli. The decorrelation is quite robust with respect to various types of perturbations of the reciprocity. The model parsimoniously captures the experimentally observed role of neurogenesis in perceptual learning and the enhanced response of young granule cells to novel stimuli. Moreover, it makes specific predictions for the type of odor enrichment that should be effective in enhancing the ability of animals to discriminate similar odor mixtures.

  14. 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.

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

    Science.gov (United States)

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

    2016-01-01

    It is well established that local field potentials (LFP) in the rodent olfactory bulb (OB) follow respiration. This respiration-related rhythm (RR) in OB depends on nasal air flow, indicating that it is conveyed by sensory inputs from the nasal epithelium. Recently RR was found outside the olfactory system, suggesting that it plays a role in organizing distributed network activity. It is therefore important to measure RR and to delineate it from endogenous electrical rhythms like theta which cover similar frequency bands in small rodents. In order to validate such measurements in freely behaving mice, we compared rhythmic LFP in the OB with two respiration-related biophysical parameters: whole-body plethysmography (PG) and nasal temperature (thermocouple; TC). During waking, all three signals reflected respiration with similar reliability. Peak power of RR in OB decreased with increasing respiration rate whereas power of PG increased. During NREM sleep, respiration-related TC signals disappeared and large amplitude slow waves frequently concealed RR in OB. In this situation, PG provided a reliable signal while breathing-related rhythms in TC and OB returned only during microarousals. In summary, local field potentials in the olfactory bulb do reliably reflect respiratory rhythm during wakefulness and REM sleep but not during NREM sleep. PMID:27247803

  16. [Activity of glial cells in the olfactory bulb of Niemann-Pick disease type C1 mice].

    Science.gov (United States)

    Yan, Xin; Qiao, Liang; Yang, En-Hui; Lin, Jun-Tang

    2016-04-25

    To study the pathological mechanisms of Niemann-Pick disease type C1, we observed the changes of activation of glial cells in the olfactory bulb of Npc1 mutant (Npc1(-/-)) mice. The genomic DNA was extracted from mouse tails for genotyping by PCR. Immunofluorescent histochemistry was performed to examine the activation of microglia and astrocytes in the olfactory bulb of Npc1(-/-) mice on postnatal day 30. NeuN, phosphorylated neurofilament (NF), Doublecortin (DCX), CD68 and GFAP were detected by Western blot. The results showed that Npc1 gene mutation strongly increased the activation of astrocytes and microglia in olfactory bulb associated with increased protein levels of CD68 and GFAP. Furthermore, the expression of phosphorylated NF was also significantly increased in the olfactory bulb of Npc1(-/-) mice compared with that in Npc1(+/+) mice. However, DCX expression was significantly reduced. The above results suggest that there are some early changes in the olfactory bulb of Npc1(-/-) mice. PMID:27108900

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

    Science.gov (United States)

    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

  18. Activation of raphe nuclei triggers rapid and distinct effects on parallel olfactory bulb output channels.

    Science.gov (United States)

    Kapoor, Vikrant; Provost, Allison C; Agarwal, Prateek; Murthy, Venkatesh N

    2016-02-01

    The serotonergic raphe nuclei are involved in regulating brain states over timescales of minutes and hours. We examined more rapid effects of raphe activation on two classes of principal neurons in the mouse olfactory bulb, mitral and tufted cells, which send olfactory information to distinct targets. Brief stimulation of the raphe nuclei led to excitation of tufted cells at rest and potentiation of their odor responses. While mitral cells at rest were also excited by raphe activation, their odor responses were bidirectionally modulated, leading to improved pattern separation of odors. In vitro whole-cell recordings revealed that specific optogenetic activation of raphe axons affected bulbar neurons through dual release of serotonin and glutamate. Therefore, the raphe nuclei, in addition to their role in neuromodulation of brain states, are also involved in fast, sub-second top-down modulation similar to cortical feedback. This modulation can selectively and differentially sensitize or decorrelate distinct output channels. PMID:26752161

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

    Directory of Open Access Journals (Sweden)

    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.

  20. Adult Born Olfactory Bulb Dopaminergic Interneurons: Molecular Determinants and Experience-Dependent Plasticity

    Science.gov (United States)

    Bonzano, Sara; Bovetti, Serena; Gendusa, Claudio; Peretto, Paolo; De Marchis, Silvia

    2016-01-01

    The olfactory bulb (OB) is a highly plastic brain region involved in the early processing of olfactory information. A remarkably feature of the OB circuits in rodents is the constitutive integration of new neurons that takes place during adulthood. Newborn cells in the adult OB are mostly inhibitory interneurons belonging to chemically, morphologically and functionally heterogeneous types. Although there is general agreement that adult neurogenesis in the OB plays a key role in sensory information processing and olfaction-related plasticity, the contribution of each interneuron subtype to such functions is far to be elucidated. Here, we focus on the dopaminergic (DA) interneurons: we highlight recent findings about their morphological features and then describe the molecular factors required for the specification/differentiation and maintenance of the DA phenotype in adult born neurons. We also discuss dynamic changes of the DA interneuron population related to age, environmental stimuli and lesions, and their possible functional implications. PMID:27199651

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

    Directory of Open Access Journals (Sweden)

    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.

  2. 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

  3. 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.

  4. 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.

  5. 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.

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

    Science.gov (United States)

    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.

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

    International Nuclear Information System (INIS)

    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

  8. 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.

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

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    Benjamin eAuffarth

    2011-07-01

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

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

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    Masayuki eSakamoto

    2014-05-01

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

  11. Recording Temperature-induced Neuronal Activity through Monitoring Calcium Changes in the Olfactory Bulb of Xenopus laevis

    Science.gov (United States)

    Kludt, Eugen; Schild, Detlev

    2016-01-01

    The olfactory system, specialized in the detection, integration and processing of chemical molecules is likely the most thoroughly studied sensory system. However, there is piling evidence that olfaction is not solely limited to chemical sensitivity, but also includes temperature sensitivity. Premetamorphic Xenopus laevis are translucent animals, with protruding nasal cavities deprived of the cribriform plate separating the nose and the olfactory bulb. These characteristics make them well suited for studying olfaction, and particularly thermosensitivity. The present article describes the complete procedure for measuring temperature responses in the olfactory bulb of X. laevis larvae. Firstly, the electroporation of olfactory receptor neurons (ORNs) is performed with spectrally distinct dyes loaded into the nasal cavities in order to stain their axon terminals in the bulbar neuropil. The differential staining between left and right receptor neurons serves to identify the γ-glomerulus as the only structure innervated by contralateral presynaptic afferents. Secondly, the electroporation is combined with focal bolus loading in the olfactory bulb in order to stain mitral cells and their dendrites. The 3D brain volume is then scanned under line-illumination microscopy for the acquisition of fast calcium imaging data while small temperature drops are induced at the olfactory epithelium. Lastly, the post-acquisition analysis allows the morphological reconstruction of the thermosensitive network comprising the γ-glomerulus and its innervating mitral cells, based on specific temperature-induced Ca2+ traces. Using chemical odorants as stimuli in addition to temperature jumps enables the comparison between thermosensitive and chemosensitive networks in the olfactory bulb. PMID:27286501

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

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    Yona Golan

    2007-05-01

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

  13. 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

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2016-01-01

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

  16. Insulin modulates network activity in olfactory bulb slices: impact on odour processing

    Science.gov (United States)

    Kuczewski, Nicola; Fourcaud-Trocmé, Nicolas; Savigner, Agnès; Thevenet, Marc; Aimé, Pascaline; Garcia, Samuel; Duchamp-Viret, Patricia; Palouzier-Paulignan, Brigitte

    2014-01-01

    Odour perception depends closely on nutritional status, in animals as in humans. Insulin, the principal anorectic hormone, appears to be one of the major candidates for ensuring the link between olfactory abilities and nutritional status, by modifying processing in the olfactory bulb (OB), one of its main central targets. The present study investigates whether and how insulin can act in OB, by evaluating its action on the main output neurons activities, mitral cells (MCs), in acute rat OB slices. Insulin was found to act at two OB network levels: (1) on MCs, by increasing their excitability, probably by inhibiting two voltage-gated potassium (K+) channels; (2) on interneurons by modifying the GABAergic and on glutamatergic synaptic activity impinging on MCs, mainly reducing them. Insulin also altered the olfactory nerve (ON)-evoked excitatory postsynaptic currents in 60% of MCs. Insulin decreased or increased the ON-evoked responses in equal proportion and the direction of its effect depended on the initial neuron ON-evoked firing rate. Indeed, insulin tended to decrease the high and to increase the low ON-evoked firing rates, thereby reducing inter-MC response firing variability. Therefore, the effects of insulin on the evoked firing rates were not carried out indiscriminately in the MC population. By constructing a mathematical model, the impact of insulin complex effects on OB was assessed at the population activity level. The model shows that the reduction of variability across cells could affect MC detection and discrimination abilities, mainly by decreasing and, less frequently, increasing them, depending on odour quality. Thus, as previously proposed, this differential action of insulin on MCs across odours would allow this hormone to put the olfactory function under feeding signal control, given the discerning valence of an odour as a function of nutritional status. PMID:24710056

  17. Analgesia induced by repeated exposure to low dose X-rays in mice, and involvement of the accessory olfactory system in modulation of the radiation effects

    International Nuclear Information System (INIS)

    The effects of low-dose X-rays on mouse nociceptive behavior were examined using a formalin injected test which rated the amount of time the animals spent licking the injected hind-paw. Male ICR White Swiss mice showed a marked suppression of licking behavior after repeated low-dose X-irradiation (5 cGy/day, 6 consecutive days). The most profound effect was observed on the day 30 after irradiation. The decline of licking behavior, however, was not observed at all following olfactory bulbectomy or vomeronasal tract cut. The analgesic effects could be observed in writhing animals administered acetic-acid intraperitoneally. Moreover, analgesia was totally blocked by the administration of N-nitro-L-arginine, a nitric oxide synthase inhibitor, to accessory olfactory bulbs prior to the exposure. The present results indicate that the olfactory system plays an important role in modulation of radiation-induced analgesia, and a possible involvement of nitric oxide in the formation of recognition memory subjected to repeated X-rays. Relatively higher doses (5 cGy x 9 days, 5 cGy x 12 days), however, did not induce such effects, namely, the decline of nociceptive response was limited to the animals irradiated with the smaller dose. (author)

  18. Control of Mitral/Tufted Cell Output by Selective Inhibition among Olfactory Bulb Glomeruli.

    Science.gov (United States)

    Economo, Michael N; Hansen, Kyle R; Wachowiak, Matt

    2016-07-20

    Inhibition is fundamental to information processing by neural circuits. In the olfactory bulb (OB), glomeruli are the functional units for odor information coding, but inhibition among glomeruli is poorly characterized. We used two-photon calcium imaging in anesthetized and awake mice to visualize both odorant-evoked excitation and suppression in OB output neurons (mitral and tufted, MT cells). MT cell response polarity mapped uniformly to discrete OB glomeruli, allowing us to analyze how inhibition shapes OB output relative to the glomerular map. Odorants elicited unique patterns of suppression in only a subset of glomeruli in which such suppression could be detected, and excited and suppressed glomeruli were spatially intermingled. Binary mixture experiments revealed that interglomerular inhibition could suppress excitatory mitral cell responses to odorants. These results reveal that inhibitory OB circuits nonlinearly transform odor representations and support a model of selective and nonrandom inhibition among glomerular ensembles. PMID:27346531

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

    International Nuclear Information System (INIS)

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

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

    OpenAIRE

    Ribeiro, Pedro F. M.; Manger, Paul R.; Catania, Kenneth C.; Kaas, Jon H.; Herculano-Houzel, Suzana

    2014-01-01

    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...

  1. 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.

  2. Olfactory bulb ablation in the rat: behavioural changes and their reversal by antidepressant drugs.

    Science.gov (United States)

    van Riezen, H; Schnieden, H; Wren, A F

    1977-01-01

    1. The effects of bilateral olfactory bulbectomy, sham-operation and inducement of peripheral anosmia were studied on locomotor activity, passive avoidance acquisition and irritability. 2. Bulbectomized rats were hyperactive, deficient at learning a step-down passive avoidance response and hyperirritable. Peripheral anosmia, induced by intranasal infusion of ZnSO4 solution resulted in no behavioural changes. 3. Chronic pretreatment with amitriptyline (3 and 10 mg/kg) and a tetracyclic antidepressant mianserin (Org GB 94, 5 and 15 mg/kg) reversed the hyperactivity and reduced the learning deficit of bulbectomized rats. These drugs had no significant effects on sham-operated animals. 4. Neither amitriptyline nor mianserin reduced the exaggerated responses of bulbectomized rats to external stimuli. 5. (+)-Amphetamine (1 and 3 mg/kg) accelerated the acquisition of the passive avoidance response, greatly enhanced the locomotor activity and slightly increased the irritability score of both sham-operated and bulbectomized rats. 6. Chlorpromazine (1 and 3 mg/kg) and chlordiazepoxide (10 mg/kg) significantly reduced the acquisition, locomotor activity and irritability of experimental and control rats. 7. Lithium sulphate (1 and 3 mg/kg) had no effect on activity or irritability but produced a small impairment in acquistion of bulbectomized rats. 8. It is concluded that the reversal by antidepressant drugs of the behavioural syndrome seen after olfactory bulb ablation could constitute a new model for the detection of this group of centrally acting compounds. PMID:907867

  3. 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.

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

    International Nuclear Information System (INIS)

    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 D2 type in mammals. The present study assessed, in the frog, both the anatomical localization of D2-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 [125I]iodosulpride-labelled D2 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 D2 antagonist eticlopride blocked the dopamine-induced reduction of mitral cell spontaneous activity.In the frog olfactory bulb, both anatomical localization of D2-like receptors and functional data on dopamine involvement in information processing differ from those reported in mammals. This suggests a phylogenetic evolution of dopamine action in the olfactory bulb. In the frog, anatomical data perfectly corroborate electrophysiological results, together strongly suggesting a direct action of dopamine on mitral cells. In a physiologically operating system, such an action would result in a global improvement of signal-to-noise ratio. (Copyright (c) 1997 Elsevier Science B.V., Amsterdam. All rights reserved.)

  5. 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

  6. 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.

  7. Increased Olfactory Bulb BDNF Expression Does Not Rescue Deficits in Olfactory Neurogenesis in the Huntington's Disease R6/2 Mouse.

    Science.gov (United States)

    Smail, Shamayra; Bahga, Dalbir; McDole, Brittnee; Guthrie, Kathleen

    2016-03-01

    Huntington's disease (HD) is an inherited neurodegenerative disorder caused by expansion of CAG trinucleotide repeats in the huntingtin gene. Mutant huntingtin protein (mhtt) interferes with the actions of brain-derived neurotrophic factor (BDNF), and BDNF signaling is reduced in the diseased striatum. Loss of this trophic support is thought to contribute to loss of striatal medium spiny neurons in HD. Increasing BDNF in the adult striatum or ventricular ependyma slows disease progression in HD mouse models, and diverts subventricular zone (SVZ)-derived neuroblasts from their normal destination, the olfactory bulb, to the striatum, where some survive and develop features of mature neurons. Most neuroblasts that migrate to the olfactory bulb differentiate as granule cells, with approximately half surviving whereas others undergo apoptosis. In the R6/2 HD mouse model, survival of adult-born granule cells is reduced. Newly maturing cells express the BDNF receptor TrkB, suggesting that mhtt may interfere with normal BDNF trophic activity, increasing their loss. To determine if augmenting BDNF counteracts this, we examined granule cell survival in R6/2 mice that overexpress BDNF in olfactory bulb. Although we detected a decline in apoptosis, increased BDNF was not sufficient to normalize granule cell survival within their normal target in R6/2 mice. PMID:26783111

  8. 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.

  9. 'When an old rat smells a cat': A decline in defense-related, but not accessory olfactory, Fos expression in aged rats.

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    Hunt, Glenn E; Van Nieuwenhuijzen, Petra S; Chan-Ling, Tailoi; McGregor, Iain S

    2011-04-01

    Comparisons were made between young (3-6 months) and aged (20-30 months) Wistar rats on locomotor activity, emergence, social interaction and cat odor avoidance. Aged rats were less active and spent less time in the open field during the emergence test than younger rats. Older rats also showed fewer contacts with a novel conspecific in the social interaction test, although total duration of interaction did not differ. There were very few behavioral differences between male and female rats. Older rats were less reactive than younger rats in a test of cat odor avoidance. However, they expressed similar amounts of cat odor-induced Fos in the posterior accessory olfactory bulb, a critical region for processing the predator odor stimulus. Older rats had reduced Fos expression in several defense-related brain regions that are normally activated by predator odors such as the medial amygdala and dorsal premammillary nucleus. These results indicate that aged rats are less reactive than younger rats to predator odors due to decreased responsiveness in defense-related but not necessarily olfactory circuits. PMID:19394115

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

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    Dolly eAl Koborssy

    2014-10-01

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

  11. Impaired olfactory bulb neurogenesis depends on the presence of human wild-type alpha-synuclein.

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    May, V E L; Nuber, S; Marxreiter, F; Riess, O; Winner, B; Winkler, J

    2012-10-11

    Synucleinopathies including Parkinson's disease (PD) are characterized by the accumulation of alpha-synuclein (α-syn) within neural cell bodies and their processes. Transgenic mice overexpressing human wild-type or mutant forms of α-syn under the control of different promoters were developed to analyse the underlying neuropathology of PD. One of the earliest clinical symptoms associated with PD is olfactory impairment. The generation of new neurons persists up to adulthood in mammals, in particular the olfactory bulb (OB). In order to assess this process in relation to α-syn accumulation, we used mice overexpressing human wild-type α-syn under the regulatable control (tet-off) of the calcium/calmodulin-dependent protein kinase IIα-promoter (CaMKII). We observed a decrease in OB neurogenesis in transgenic animals compared to controls using 5-bromo-2'-deoxyuridine (BrdU) to label newly generated cells (neuron-specific nuclear protein; NeuN). After cessation of transgene expression we detected an increase in newly generated cells both in granular (GCL) and glomerular (GLOM) layers of the OB. This led to a rescue of newly generated neurons (BrdU(+)/NeuN(+)) within the GLOM with a distinct specificity for the dopaminergic subpopulation. In contrast, we did not detect a cell-specific rescue of neuronal cells in the GCL suggesting diverse effects of alpha-synucleinopathy in both interneuronal layers of the OB. Colabelling of BrdU with glial markers showed that a differentiation into neither astroglia nor microglia attributed to the observed phenotype in the GCL. In particular, BrdU(+) particles located within microglial cells were predominantly associated close to the membrane therefore the resembling phagocytosed nuclear fragments of BrdU(+) cells. Thus, our study further contributes insights into α-syn accumulation as a causative player in the impairment of adult neurogenesis and emphasizes its diverse role in cell renewal of distinct OB cell layers. PMID:22814000

  12. Ligand binding studies in the mouse olfactory bulb: identification and characterisation of a L-[3H]carnosine binding site

    International Nuclear Information System (INIS)

    Binding sites for the dipeptide L-carnosine (β-alanyl-t-histidine) have been detected in membranes prepared from mouse olfactory bulbs. The binding of L-[3H]- carnosine was saturable, reversible and stereospecific and had a Ksub(d) of about 770 nM. The stereospecific binding of L-carnosine represented about 30% of the totoal binding at pH 6.8, and decreased markedly with increasing pH. Binding was stimulated by calcium, unaffected by zinc, magnesium or manganese and inhibted by sodium and potassium. Carnosine binding was sensitive to trypsin and phospholipases A and C, but not to neuraminidase. Nystatin and filipin, which interact with membrane lipids, also interfered with binding. Some peptide analogues of carnosine were potent inhibitors of binding, but a variety of drugs serving as potent inhibitors in other binding systems had no effect on carnosine binding. Carnosine binding to mouse olfactory bulb membranes was 15-fold higher than that seen in membranes prepared from cerebral hemispheres, 5-fold higher than in cerebellum membranes and 3-fold higher than in membranes from spinal medulla and the olfactory tubercle-lateral olfactory tract area. (Auth.)

  13. 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

  14. 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.

  15. 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.

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

    Science.gov (United States)

    Lim, Daniel A; Alvarez-Buylla, Arturo

    2016-01-01

    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. PMID:27048191

  17. Role of the Retinoblastoma protein, Rb, during adult neurogenesis in the olfactory bulb.

    Science.gov (United States)

    Naser, Rayan; Vandenbosch, Renaud; Omais, Saad; Hayek, Dayana; Jaafar, Carine; Al Lafi, Sawsan; Saliba, Afaf; Baghdadi, Maarouf; Skaf, Larissa; Ghanem, Noël

    2016-01-01

    Adult neural stem cells (aNSCs) are relatively quiescent populations that give rise to distinct neuronal subtypes throughout life, yet, at a very low rate and restricted differentiation potential. Thus, identifying the molecular mechanisms that control their cellular expansion is critical for regeneration after brain injury. Loss of the Retinoblastoma protein, Rb, leads to several defects in cell cycle as well as neuronal differentiation and migration during brain development. Here, we investigated the role of Rb during adult neurogenesis in the olfactory bulb (OB) by inducing its temporal deletion in aNSCs and progenitors. Loss of Rb was associated with increased proliferation of adult progenitors in the subventricular zone (SVZ) and the rostral migratory stream (RMS) but did not alter self-renewal of aNSCs or neuroblasts subsequent migration and terminal differentiation. Hence, one month after their birth, Rb-null neuroblasts were able to differentiate into distinct subtypes of GABAergic OB interneurons but were gradually lost after 3 months. Similarly, Rb controlled aNSCs/progenitors proliferation in vitro without affecting their differentiation capacity. This enhanced SVZ/OB neurogenesis associated with loss of Rb was only transient and negatively affected by increased apoptosis indicating a critical requirement for Rb in the long-term survival of adult-born OB interneurons. PMID:26847607

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

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    LaRocca Greg

    2007-11-01

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

  19. New insights into the role of histamine in subventricular zone-olfactory bulb neurogenesis.

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    Maria Francisca eEiriz

    2014-06-01

    Full Text Available The subventricular zone (SVZ contains neural stem cells (NSCs that generate new neurons throughout life. Many brain diseases stimulate NSCs proliferation, neuronal differentiation and homing of these newborns cells into damaged regions. However, complete cell replacement has never been fully achieved. Hence, the identification of proneurogenic factors crucial for stem cell-based therapies will have an impact in brain repair. Histamine, a neurotransmitter and immune mediator, has been recently described to modulate proliferation and commitment of NSCs. Histamine levels are increased in the brain parenchyma and at the cerebrospinal fluid (CSF upon inflammation and brain injury, thus being able to modulate neurogenesis. Herein, we add new data showing that in vivo administration of histamine in the lateral ventricles has a potent proneurogenic effect, increasing the production of new neuroblasts in the SVZ that ultimately reach the olfactory bulb (OB. This report emphasizes the multidimensional effects of histamine in the modulation of NSCs dynamics and sheds light into the promising therapeutic role of histamine for brain regenerative medicine.

  20. Functional optical coherence tomography of rat olfactory bulb with periodic odor stimulation.

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

    2016-03-01

    In rodent olfactory bulb (OB), optical intrinsic signal imaging (OISI) is commonly used to investigate functional maps to odorant stimulations. However, in such studies, the spatial resolution in depth direction (z-axis) is lost because of the integration of light from different depths. To solve this problem, we propose functional optical coherence tomography (fOCT) with periodic stimulation and continuous recording. In fOCT experiments of in vivo rat OB, propionic acid and m-cresol were used as odor stimulus presentations. Such a periodic stimulation enabled us to detect the specific odor-responses from highly scattering brain tissue. Swept source OCT operating at a wavelength of 1334 nm and a frequency of 20 kHz, was employed with theoretical depth and lateral resolutions of 6.7 μm and 15.4 μm, respectively. We succeeded in visualizing 2D cross sectional fOCT map across the neural layer structure of OCT in vivo. The detected fOCT signals corresponded to a few glomeruli of the medial and lateral parts of dorsal OB. We also obtained 3D fOCT maps, which upon integration across z-axis agreed well with OISI results. We expect such an approach to open a window for investigating and possibly addressing toward inter/intra-layer connections at high resolutions in the future. PMID:27231593

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

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    Brill Monika S

    2011-04-01

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

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

    Science.gov (United States)

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

    2009-01-01

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

  3. Principal cell activity induces spine relocation of adult-born interneurons in the olfactory bulb.

    Science.gov (United States)

    Breton-Provencher, Vincent; Bakhshetyan, Karen; Hardy, Delphine; Bammann, Rodrigo Roberto; Cavarretta, Francesco; Snapyan, Marina; Côté, Daniel; Migliore, Michele; Saghatelyan, Armen

    2016-01-01

    Adult-born neurons adjust olfactory bulb (OB) network functioning in response to changing environmental conditions by the formation, retraction and/or stabilization of new synaptic contacts. While some changes in the odour environment are rapid, the synaptogenesis of adult-born neurons occurs over a longer time scale. It remains unknown how the bulbar network functions when rapid and persistent changes in environmental conditions occur but when new synapses have not been formed. Here we reveal a new form of structural remodelling where mature spines of adult-born but not early-born neurons relocate in an activity-dependent manner. Principal cell activity induces directional growth of spine head filopodia (SHF) followed by spine relocation. Principal cell-derived glutamate and BDNF regulate SHF motility and directional spine relocation, respectively; and spines with SHF are selectively preserved following sensory deprivation. Our three-dimensional model suggests that spine relocation allows fast reorganization of OB network with functional consequences for odour information processing. PMID:27578235

  4. 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

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

    Science.gov (United States)

    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

  6. Immunohistochemical localization of GABAergic key molecules in the main olfactory bulb of the Korean roe deer, Capreolus pygargus.

    Science.gov (United States)

    Kim, Jeongtae; Takayama, Chitoshi; Park, Changnam; Ahn, Meejung; Moon, Changjong; Shin, Taekyun

    2015-09-01

    Gamma-amino butyric acid (GABA) negatively regulates the excitatory activity of neurons and is a predominant neurotransmitter in the nervous system. The olfactory bulb, the main center in the olfactory system, is modulated by inhibitory interneurons that use GABA as their main neurotransmitter. The present study aimed to evaluate GABAergic transmission in the main olfactory bulb (MOB) of the Korean roe deer (Capreolus pygargus) by examining the immunohistochemical localization of GABAergic key molecules, including glutamic acid decarboxylase (GAD), vesicular GABA transporter (VGAT), GABA transporters (GATs; GAT-1 and GAT-3), and potassium sodium chloride co-transporter 2 (KCC2). GAD, VGAT, and KCC2 were expressed in the glomerular layer (GL), external plexiform layer (ePL), mitral cell layer (ML), and granule cell layer (GrL). Intense GAT-1 expression was observed in the GL; GAT-1 expression was discernible in the ePL, ML, and GrL. However, intense GAT-3 expression was extensively observed in all layers of the MOB. These results suggest that substantial GABAergic synapses are present in the GL, ePL, ML, and GrL. Furthermore, the released GABA may be removed by GAT-1 and GAT-3 in the GL, and the majority of GABA, which is present in the ePL to GrL, may undergo reuptake by GAT-3. This is the first morphological and descriptive study of GABAergic transmission in the MOB of Korean roe deer. PMID:26115600

  7. 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.

  8. Accessory olfactory neural Fos responses to a conditioned environment are blocked in male mice by vomeronasal organ removal

    OpenAIRE

    Pankevich, Diana E.; Cherry, James A.; Baum, Michael J.

    2006-01-01

    The ability of an anesthetized estrous female to induce a conditioned place preference (CPP) response was assessed in male mice from which the vomeronasal organ (VNO) had either been removed (VNOx) or left intact (VNOi) in an initial effort to assess the possible contribution of VNO-accessory olfactory inputs to the intrinsically rewarding properties of opposite-sex body odorants. Both VNOi and VNOx male mice acquired a CPP after repeated pairing of an initially non-preferred test chamber wit...

  9. Calcium buffering in rodent olfactory bulb granule cells and mitral cells.

    Science.gov (United States)

    Egger, Veronica; Stroh, Olga

    2009-09-15

    In the mammalian olfactory bulb, axonless granule cells (GCs) mediate self- and lateral inhibitory interactions between mitral cells (MCs) via reciprocal dendrodendritic synapses. Calcium signals in the GC dendrites and reciprocal spines appear to decay unusually slowly, hence GC calcium handling might contribute to the known asynchronous release at this synapse. By recording fluorescence transients of different Ca(2+)-sensitive dyes at variable concentrations evoked by backpropagating action potentials (APs) and saturating AP trains we extrapolated Ca(2+) dynamics to conditions of zero added buffer for juvenile rat GC apical dendrites and spines and MC lateral dendrites. Resting [Ca(2+)] was at approximately 50 nM in both GC dendrites and spines. The average endogenous GC buffer capacities (kappa(E)) were within a range of 80-90 in the dendrites and 110-140 in the spines. The extrusion rate (gamma) was estimated as 570 s(-1) for dendrites and 870 s(-1) for spines and the decay time constant as approximately 200 ms for both. Single-current-evoked APs resulted in a [Ca(2+)] elevation of approximately 250 nM. Calcium handling in juvenile and adult mouse GCs appeared mostly similar. In MC lateral dendrites, we found AP-mediated [Ca(2+)] elevations of approximately 130 nM with a similar decay to that in GC dendrites, while kappa(E) and gamma were roughly 4-fold higher. In conclusion, the slow GC Ca(2+) dynamics are due mostly to sluggish Ca(2+) extrusion. Under physiological conditions this slow removal may well contribute to delayed release and also feed into other Ca(2+)-dependent mechanisms that foster asynchronous output from the reciprocal spine. PMID:19635818

  10. Partial Conservation between Mice and Humans in Olfactory Bulb Interneuron Transcription Factor Codes.

    Science.gov (United States)

    Fujiwara, Nana; Cave, John W

    2016-01-01

    The mammalian main olfactory bulb (OB) has a large population of GABAergic inhibitory interneurons that contains several subtypes defined by the co-expression other neurotransmitters and calcium binding proteins. The three most commonly studied OB interneuron subtypes co-express either Calretinin, Calbindin, or Tyrosine hydroxylase (Th). Combinations of transcription factors used to specify the phenotype of progenitors are referred to as transcription factor codes, and the current understanding of transcription factor codes that specify OB inhibitory neuron phenotypes are largely based on studies in mice. The conservation of these transcription factor codes in the human OB, however, has not been investigated. The aim of this study was to establish whether transcription factor codes in OB interneurons are conserved between mice and humans. This study compared the co-expression of Foxp2, Meis2, Pax6, and Sp8 transcription factors with Calretinin, Calbindin, or Th in human and mouse OB interneurons. This analysis found strong conservation of Calretinin co-expression with Sp8 and Meis2 as well as Th co-expression with Pax6 and Meis2. This analysis also showed that selective Foxp2 co-expression with Calbindin was conserved between mice and humans, which suggests Foxp2 is a novel determinant of the OB Calbindin interneuron phenotype. Together, the findings in this study provide insight into the conservation of transcription codes for OB interneuron phenotypes between humans and mice, as well as reveal some important differences between the species. This advance in our understanding of transcription factor codes in OB interneurons provides an important complement to the codes that have been established for other regions within the mammalian central nervous system, such as the cortex and spinal cord. PMID:27489533

  11. 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.

  12. Acute changes in murine hippocampus and olfactory bulb after nasal instillation of varying size cerium dioxide particles.

    Science.gov (United States)

    Liu, Yang; Li, Yuanyuan; Yang, Tongwang; Yang, Jing; Wang, He; Wu, Gang

    2016-01-01

    Cerium (Ce)-containing compounds are now widely applied in medicine, agriculture, and animal breeding. However, the effects of Ce on humans, especially on the central nervous system (CNS), remain to be determined. In order to investigate whether Ce exposure affected the CNS, the aim of this study was to expose female ICR mice to varying nanoparticle sizes of 35 nm and 300 nm, and to a mixture of 1-5 µM cerium dioxide (CeO2) particles through intranasal (i.n.) instillation at daily dose of 40 mg/kg body weight. Immunohistochemical data showed that glial fibrillary acidic protein expression (GFAP) increased significantly in the hippocampus and olfactory bulb in all Ce-administered groups. The ultrastructure of olfactory bulb cells displayed chromatin reduction. In the hippocampus decreased chromatin was associated with ribosome shedding as evidenced from transmission electron microscopy (TEM). No significant differences in immunohistochemistry were noted between varying sizes of CeO2 groups. The results of inductively coupled plasma-mass spectroscopy (ICP-MS) analysis group exposed to 1-5 µM demonstrated that Ce levels were significantly higher in whole brain (0.17 ng/mg) than for the control (0.04 ng/mg). Data thus demonstrated that i.n. instillation of different sized CeO2 particles induced damage in the olfactory bulb and hippocampus and that CeO2 particle size did not appear to play a role in the observed adverse responses. PMID:27599233

  13. The effect of bilirubin on the excitability of mitral cells in the olfactory bulb of the rat.

    Science.gov (United States)

    Chen, Xiao-Juan; Zhou, Hui-Qun; Ye, Hai-Bo; Li, Chun-Yan; Zhang, Wei-Tian

    2016-01-01

    Olfactory dysfunction is a common clinical phenomenon observed in various liver diseases. Previous studies have shown a correlation between smell disorders and bilirubin levels in patients with hepatic diseases. Bilirubin is a well-known neurotoxin; however, its effect on neurons in the main olfactory bulb (MOB), the first relay in the olfactory system, has not been examined. We investigated the effect of bilirubin (>3 μM) on mitral cells (MCs), the principal output neurons of the MOB. Bilirubin increased the frequency of spontaneous firing and the frequency but not the amplitude of spontaneous excitatory postsynaptic currents (sEPSCs). TTX completely blocked sEPSCs in almost all of the cells tested. Bilirubin activity was partially blocked by N-methyl-D-aspartate (NMDA) and α-amino-3-hydroxy-5-methyl-4-isoxazolepro pionic acid (AMPA) receptor antagonists. Furthermore, we found that bilirubin increased the frequency of intrinsic firing independent of synaptic transmission in MCs. Our findings suggest that bilirubin enhances glutamatergic transmission and strengthens intrinsic firing independent of synaptic transmission, all of which cause hyperexcitability in MCs. Our findings provide the basis for further investigation into the mechanisms underlying olfactory dysfunction that are often observed in patients with severe liver disease. PMID:27611599

  14. Gestational methyl donor deficiency alters key proteins involved in neurosteroidogenesis in the olfactory bulbs of newborn female rats and is associated with impaired olfactory performance.

    Science.gov (United States)

    El Hajj Chehadeh, Sarah; Pourié, Grégory; Martin, Nicolas; Alberto, Jean-Marc; Daval, Jean-Luc; Guéant, Jean-Louis; Leininger-Muller, Brigitte

    2014-03-28

    Gestational methyl donor deficiency (MDD) leads to growth retardation as well as to cognitive and motor disorders in 21-d-old rat pups. These disorders are related to impaired neurogenesis in the cerebral neurogenic areas. Olfactory bulbs (OB), the main target of neuronal progenitors originating from the subventricular zone, play a critical role during the postnatal period by allowing the pups to identify maternal odour. We hypothesised that growth retardation could result from impaired suckling due to impaired olfactory discrimination through imbalanced apoptosis/neurogenesis in the OB. Since neurosteroidogenesis modulates neurogenesis in OB, in the present study, we investigated whether altered neurosteroidogenesis could explain some these effects. Pups born to dams fed a normal diet (n 24) and a MDD diet (n 27) were subjected to olfactory tests during the lactation and weaning periods (n 24 and 20, respectively). We studied the markers of apoptosis/neurogenesis and the expression levels of the key neurosteroidogenic enzyme aromatase, the cholesterol-transfer protein StAR (steroidogenic acute regulatory protein) and the ERα oestrogen receptor and the content of oestradiol in OB. The 21-d-old MDD female pups displayed lower body weight and impaired olfactory discrimination when compared with the control pups. MDD led to greater homocysteine accumulation and more pronounced apoptosis, along with impaired cell proliferation in the OB of female pups. The expression levels of aromatase, StAR and ERα as well as the content of oestradiol were lower in the OB of the MDD female pups than in those of the control female pups. In conclusion, gestational MDD may alter olfactory discrimination performances by affecting neurogenesis, apoptosis and neurosteroidogenesis in OB in a sex-dependent manner. It may be involved in growth retardation through impaired suckling.

  15. Trpc2 gene impacts on maternal aggression, accessory olfactory bulb anatomy, and brain activity

    OpenAIRE

    Hasen, Nina S.; Gammie, Stephen C.

    2009-01-01

    The trpc2 gene codes for an ion channel found in the vomeronasal organ (VNO). Studies using the trpc2−/− (KO) mouse have exploited the gene's role in signal transduction to explore the VNO's role in pheromonally-mediated behaviors. To date, no study has evaluated the impact of the trpc2 gene on activity within the brain. Here, we examine the gene's effect on brain regions governing maternal aggression. We intruder-tested lactating dams and then quantified Fos immunoreactivity (Fos-IR) in the ...

  16. Reduced proliferation in the adult mouse subventricular zone increases survival of olfactory bulb interneurons.

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    Yi Sui

    Full Text Available Neurogenesis in the adult brain is largely restricted to the subependymal zone (SVZ of the lateral ventricle, olfactory bulb (OB and the dentate subgranular zone, and survival of adult-born cells in the OB is influenced by factors including sensory experience. We examined, in mice, whether survival of adult-born cells is also regulated by the rate of precursor proliferation in the SVZ. Precursor proliferation was decreased by depleting the SVZ of dopamine after lesioning dopamine neurons in the substantia nigra compacta with 6-hydroxydopamine. Subsequently, we examined the effect of reduced SVZ proliferation on the generation, migration and survival of neuroblasts and mature adult-born cells in the SVZ, rostral migratory stream (RMS and OB. Proliferating cells in the SVZ, measured by 5-bromo-2-deoxyuridine (BrdU injected 2 hours prior to death or by immunoreactivity against Ki67, were reduced by 47% or 36%, respectively, 7 days after dopamine depletion, and by 29% or 31% 42 days after dopamine depletion, compared to sham-treated animals. Neuroblast generation in the SVZ and their migration along the RMS were not affected, neither 7 nor 42 days after the 6-hydroxydopamine injection, since the number of doublecortin-immunoreactive neuroblasts in the SVZ and RMS, as well as the number of neuronal nuclei-immunoreactive cells in the OB, were stable compared to control. However, survival analysis 15 days after 6-hydroxydopamine and 6 days after BrdU injections showed that the number of BrdU+ cells in the SVZ was 70% higher. Also, 42 days after 6-hydroxydopamine and 30 days after BrdU injections, we found an 82% increase in co-labeled BrdU+/γ-aminobutyric acid-immunoreactive cell bodies in the granular cell layer, while double-labeled BrdU+/tyrosine hydroxylase-immunoreactive cell bodies in the glomerular layer increased by 148%. We conclude that the number of OB interneurons following reduced SVZ proliferation is maintained through an increased

  17. Robust encoding of stimulus identity and concentration in the accessory olfactory system.

    Science.gov (United States)

    Arnson, Hannah A; Holy, Timothy E

    2013-08-14

    Sensory systems represent stimulus identity and intensity, but in the neural periphery these two variables are typically intertwined. Moreover, stable detection may be complicated by environmental uncertainty; stimulus properties can differ over time and circumstance in ways that are not necessarily biologically relevant. We explored these issues in the context of the mouse accessory olfactory system, which specializes in detection of chemical social cues and infers myriad aspects of the identity and physiological state of conspecifics from complex mixtures, such as urine. Using mixtures of sulfated steroids, key constituents of urine, we found that spiking responses of individual vomeronasal sensory neurons encode both individual compounds and mixtures in a manner consistent with a simple model of receptor-ligand interactions. Although typical neurons did not accurately encode concentration over a large dynamic range, from population activity it was possible to reliably estimate the log-concentration of pure compounds over several orders of magnitude. For binary mixtures, simple models failed to accurately segment the individual components, largely because of the prevalence of neurons responsive to both components. By accounting for such overlaps during model tuning, we show that, from neuronal firing, one can accurately estimate log-concentration of both components, even when tested across widely varying concentrations. With this foundation, the difference of logarithms, log A - log B = log A/B, provides a natural mechanism to accurately estimate concentration ratios. Thus, we show that a biophysically plausible circuit model can reconstruct concentration ratios from observed neuronal firing, representing a powerful mechanism to separate stimulus identity from absolute concentration. PMID:23946396

  18. 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

  19. 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.

  20. 2D-gel based proteomics unravels neurogenesis and energetic metabolism dysfunction of the olfactory bulb in CUMS rat model.

    Science.gov (United States)

    Cheng, Ke; Li, Juan; Yang, Deyu; Yang, Yongtao; Rao, Chenglong; Zhang, Shuxiao; Wang, Wei; Guo, Hua; Fang, Liang; Zhu, Dan; Han, Yu; Xie, Peng

    2016-10-15

    Major depression is a devastating psychiatric disease worldwide currently. A reduced olfactory sensitivity in MDD patients was well evidenced. We previously interrogated the mechanism of decreasing hippocampus neurogenesis in CUMS rat model of depression. The Olfactory Bulb (OB) is crucial part of the olfactory system which functions in post-developmental neurogenesis. However, the mechanism of the dysfunction of OB induced by CUMS is still largely unknown. Herein, by using the chronic unpredictable mild stress (CUMS) rat model of depression, differential protein expression between the OB proteomes of CUMS and control group was interrogated through two-dimensional electrophoresis coupling with matrix-assisted laser desorption ionization-time of flight tandem mass spectrometry. Twenty nine differential protein expression was analyzed by Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway over-representation and Ingenuity pathways analysis (IPA). Seven identified differential proteins were selected for Western blotting validation. This study provides insight that neurogenesis and Energy metabolism disorder is involved in OB dysfunction induced by CUMS. PMID:27340088

  1. 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.

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

    NARCIS (Netherlands)

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

    2013-01-01

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

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

    Directory of Open Access Journals (Sweden)

    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.

  4. 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.

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

    Directory of Open Access Journals (Sweden)

    Tingting eSun

    2016-05-01

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

  6. Anosmin-1 over-expression increases adult neurogenesis in the subventricular zone and neuroblast migration to the olfactory bulb.

    Science.gov (United States)

    García-González, Diego; Murcia-Belmonte, Verónica; Esteban, Pedro F; Ortega, Felipe; Díaz, David; Sánchez-Vera, Irene; Lebrón-Galán, Rafael; Escobar-Castañondo, Laura; Martínez-Millán, Luis; Weruaga, Eduardo; García-Verdugo, José Manuel; Berninger, Benedikt; de Castro, Fernando

    2016-01-01

    New subventricular zone (SVZ)-derived neuroblasts that migrate via the rostral migratory stream are continuously added to the olfactory bulb (OB) of the adult rodent brain. Anosmin-1 (A1) is an extracellular matrix protein that binds to FGF receptor 1 (FGFR1) to exert its biological effects. When mutated as in Kallmann syndrome patients, A1 is associated with severe OB morphogenesis defects leading to anosmia and hypogonadotropic hypogonadism. Here, we show that A1 over-expression in adult mice strongly increases proliferation in the SVZ, mainly with symmetrical divisions, and produces substantial morphological changes in the normal SVZ architecture, where we also report the presence of FGFR1 in almost all SVZ cells. Interestingly, for the first time we show FGFR1 expression in the basal body of primary cilia in neural progenitor cells. Additionally, we have found that A1 over-expression also enhances neuroblast motility, mainly through FGFR1 activity. Together, these changes lead to a selective increase in several GABAergic interneuron populations in different OB layers. These specific alterations in the OB would be sufficient to disrupt the normal processing of sensory information and consequently alter olfactory memory. In summary, this work shows that FGFR1-mediated A1 activity plays a crucial role in the continuous remodelling of the adult OB. PMID:25300351

  7. Altered Morphologies and Functions of the Olfactory Bulb and Hippocampus Induced by miR-30c.

    Science.gov (United States)

    Sun, Tingting; Li, Tianpeng; Davies, Henry; Li, Weiyun; Yang, Jing; Li, Shanshan; Ling, Shucai

    2016-01-01

    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 3 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. PMID:27242411

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

    Science.gov (United States)

    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

  9. Two distinct olfactory bulb sublaminar networks involved in gamma and beta oscillation generation: a CSD study in the anesthetized rat.

    Directory of Open Access Journals (Sweden)

    Nicolas eFourcaud-Trocmé

    2014-07-01

    Full Text Available A prominent feature of olfactory bulb (OB dynamics is the expression of characteristic local field potential (LFP rhythms, including a slow respiration-related rhythm and two fast alternating oscillatory rhythms, beta (15-30 Hz and gamma (40-90 Hz. All of these rhythms are implicated in olfactory coding. Fast oscillatory rhythms are known to involve the mitral-granule cell loops. Although the underlying mechanisms of gamma oscillation have been studied, the origin of beta oscillation remains poorly understood. Whether these two different rhythms share the same underlying mechanism is unknown. This study uses a quantitative and detailed current-source density analysis combined with multi-unit activity recordings to shed light on this question in freely breathing anesthetized rats. In particular, we show that gamma oscillation generation involves mainly upper half of the external plexiform layer (EPL and superficial areas of granule cell layer. In contrast, the generation of beta oscillation involves the lower part of the EPL and deep granule cells. This differential involvement of sublaminar networks is neither dependent on odor quality nor on the precise frequency of the fast oscillation under study. Overall, this study demonstrates a functional sublaminar organization of the rat OB, which is supported by previous anatomical findings.

  10. 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.

  11. Sex hormone binding globulin in the rat olfactory system.

    Science.gov (United States)

    Ploss, V; Gebhart, V M; Dölz, W; Jirikowski, G F

    2014-05-01

    Ovarian steroids are known to act on the olfactory system. Their mode of action, however, is mostly unclear to date since nuclear receptors are lacking in sensory neurons. Here we used immunocytochemistry and RT-PCR to study expression and distribution of sex hormone binding globulin (SHBG) in the rat olfactory system. Single sensory cells in the olfactory mucosa and their projections in the olfactory bulb showed specific SHBG immunostaining as determined by double immunofluorescence with olfactory marker protein OMP. Larger groups of SHBG stained sensory cells occurred in the vomeronasal organ (VNO). A portion of the olfactory glomeruli in the accessory olfactory bulb showed large networks of SHBG positive nerve fibres. Some of the mitral cells showed SHBG immune fluorescence. RT-PCR revealed SHBG encoding mRNA in the olfactory mucosa, in the VNO and in the olfactory bulbs indicating intrinsic expression of the binding globulin. The VNO and its related projections within the limbic system are known to be sensitive to gonadal steroid hormones. We conclude that SHBG may be of functional importance for rapid effects of olfactory steroids on limbic functions including the control of reproductive behaviours through pheromones. PMID:24681170

  12. 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

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

    OpenAIRE

    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 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 ische...

  14. 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.

  15. 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.

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

    Science.gov (United States)

    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.

  17. Changes in adult olfactory bulb neurogenesis in mice expressing the A30P mutant form of alpha-synuclein.

    Science.gov (United States)

    Marxreiter, Franz; Nuber, Silke; Kandasamy, Mahesh; Klucken, Jochen; Aigner, Robert; Burgmayer, Ralf; Couillard-Despres, Sebastien; Riess, Olaf; Winkler, Jürgen; Winner, Beate

    2009-03-01

    In familial and sporadic forms of Parkinson's disease (PD), alpha-synuclein pathology is present in the brain stem nuclei and olfactory bulb (OB) long before Lewy bodies are detected in the substantia nigra. The OB is an active region of adult neurogenesis, where newly generated neurons physiologically integrate. While accumulation of wild-type alpha-synuclein is one of the pathogenic hallmarks of non-genetic forms of PD, the A30P alpha-synuclein mutation results in an earlier disease onset and a severe clinical phenotype. Here, we study the regulation of adult neurogenesis in the subventricular zone (SVZ)/OB system in a tetracycline-suppressive (tet-off) transgenic model of synucleinopathies, expressing human mutant A30P alpha-synuclein under the control of the calcium/calmodulin-dependent protein kinase II alpha (CaMK) promoter. In A30P transgenic mice alpha-synuclein was abundant at the site of integration in the glomerular cell layer of the OB. Without changes in proliferation in the SVZ, significantly fewer newly generated neurons were observed in the OB granule cell and glomerular layers of A30P transgenic mice than in controls, most probably due to increased cell death. By tetracycline-dependent abrogation of A30P alpha-synuclein expression, OB neurogenesis and programmed cell death was restored to control levels. Our results indicate that, using A30P conditional (tet-off) mice, A30P alpha-synuclein has a negative impact on olfactory neurogenesis and suppression of A30P alpha-synuclein enhances survival of newly generated neurons. This finding suggests that interfering with alpha-synuclein pathology can rescue newly generated neurons, possibly leading to new targets for therapeutic interventions in synucleinopathies. PMID:19291219

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

    Directory of Open Access Journals (Sweden)

    Arthur William Barrios

    2014-07-01

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

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

    Science.gov (United States)

    Barrios, Arthur W; Núñez, Gonzalo; Sánchez Quinteiro, Pablo; Salazar, Ignacio

    2014-01-01

    The four regions of the murine nasal cavity featuring olfactory neurons were studied anatomically and by labeling with lectins and relevant antibodies with a view to establishing criteria for the identification of olfactory subsystems that are readily applicable to other mammals. In the main olfactory epithelium and the septal organ the olfactory sensory neurons (OSNs) are embedded in quasi-stratified columnar epithelium; vomeronasal OSNs are embedded in epithelium lining the medial interior wall of the vomeronasal duct and do not make contact with the mucosa of the main nasal cavity; and in Grüneberg's ganglion a small isolated population of OSNs lies adjacent to, but not within, the epithelium. With the exception of Grüneberg's ganglion, all the tissues expressing olfactory marker protein (OMP) (the above four nasal territories, the vomeronasal and main olfactory nerves, and the main and accessory olfactory bulbs) are also labeled by Lycopersicum esculentum agglutinin, while Ulex europaeus agglutinin I labels all and only tissues expressing Gαi2 (the apical sensory neurons of the vomeronasal organ, their axons, and their glomerular destinations in the anterior accessory olfactory bulb). These staining patterns of UEA-I and LEA may facilitate the characterization of olfactory anatomy in other species. A 710-section atlas of the anatomy of the murine nasal cavity has been made available on line. PMID:25071468

  20. The development of the olfactory organs in newly hatched monotremes and neonate marsupials.

    Science.gov (United States)

    Schneider, Nanette Yvette

    2011-08-01

    Olfactory cues are thought to play a crucial role in the detection of the milk source at birth in mammals. It has been shown that a marsupial, the tammar wallaby, can detect olfactory cues from its mother's pouch at birth. This study investigates whether the main olfactory and accessory olfactory system are similarly well developed in other marsupials and monotremes at birth/hatching as in the tammar. Sections of the head of various marsupial and two monotreme species were investigated by light microscopy. Both olfactory systems were less well developed in the kowari and Eastern quoll. No olfactory or vomeronasal or terminal nerves could be observed; the main olfactory bulb (MOB) had only two layers while no accessory olfactory bulb or ganglion terminale were visible. All other investigated marsupials and monotremes showed further developed olfactory systems with olfactory, vomeronasal and terminal nerves, a three-layered MOB, and in the marsupials a prominent ganglion terminale. The main olfactory system was further developed than the accessory olfactory system in all species investigated. The olfactory systems were the least developed in species in which the mother's birth position removed most of the difficulty in reaching the teat, placing the neonate directly in the pouch. In monotremes they were the furthest developed as Bowman glands were found underlying the main olfactory epithelium. This may reflect the need to locate the milk field each time they drink as they cannot permanently attach to it, unlike therian mammals. While it still needs to be determined how an odour signal could be further processed in the brain, this study suggests that marsupials and monotremes possess well enough developed olfactory systems to be able to detect an odour cue from the mammary area at birth/hatching. It is therefore likely that neonate marsupials and newly hatched monotremes find their way to the milk source using olfactory cues, as has been previously suggested for the

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

    Science.gov (United States)

    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.

  2. Aberrant Adult Neurogenesis in the Subventricular Zone-Rostral Migratory Stream-Olfactory Bulb System Following Subchronic Manganese Exposure.

    Science.gov (United States)

    Fu, Sherleen; Jiang, Wendy; Gao, Xiang; Zeng, Andrew; Cholger, Daniel; Cannon, Jason; Chen, Jinhui; Zheng, Wei

    2016-04-01

    Adult neurogenesis occurs in brain subventricular zone (SVZ). Our recent data reveal an elevated proliferation of BrdU(+) cells in SVZ following subchronic manganese (Mn) exposure in rats. This study was designed to distinguish Mn effect on the critical stage of adult neurogenesis, ie, proliferation, migration, survival and differentiation from the SVZ via the rostral migratory stream to the olfactory bulb (OB). Adult rats received a single ip-dose of BrdU at the end of 4-week Mn exposure to label proliferating cells. Immunostaining and cell-counting showed a 48% increase of BrdU(+) cells in Mn-exposed SVZ than in controls (Padult rats received 3 daily ip-injections of BrdU followed by subchronic Mn exposure. By 4-week post BrdU labeling, most of the surviving BrdU(+) cells in the OB were differentiated into NeuN(+) matured neurons. However, survival rates of BrdU/NeuN/DAPI triple-labeled cells in OB were 33% and 64% in Mn-exposed and control animals, respectively (Padult SVZ. In the OB, however, Mn exposure significantly reduces the surviving adult-born cells and markedly inhibits their differentiation into mature neurons, resulting in an overall decreased adult neurogenesis in the OB. PMID:26794142

  3. Distinct lateral inhibitory circuits drive parallel processing of sensory information in the mammalian olfactory bulb

    Science.gov (United States)

    Geramita, Matthew A; Burton, Shawn D; Urban, Nathan N

    2016-01-01

    Splitting sensory information into parallel pathways is a common strategy in sensory systems. Yet, how circuits in these parallel pathways are composed to maintain or even enhance the encoding of specific stimulus features is poorly understood. Here, we have investigated the parallel pathways formed by mitral and tufted cells of the olfactory system in mice and characterized the emergence of feature selectivity in these cell types via distinct lateral inhibitory circuits. We find differences in activity-dependent lateral inhibition between mitral and tufted cells that likely reflect newly described differences in the activation of deep and superficial granule cells. Simulations show that these circuit-level differences allow mitral and tufted cells to best discriminate odors in separate concentration ranges, indicating that segregating information about different ranges of stimulus intensity may be an important function of these parallel sensory pathways. DOI: http://dx.doi.org/10.7554/eLife.16039.001 PMID:27351103

  4. Effect of prenatal androgen receptor antagonist or aromatase inhibitor on the differentiation of neuronal Fos responses to estrous female pheromones in the rat accessory olfactory system

    OpenAIRE

    Dominguez, Emilio; Portillo, Wendy; Baum, Michael J.; Bakker, Julie; Paredes, Raul

    2002-01-01

    Many socially relevant odors are detected in rodent species by the vomeronasal organ and subsequently processed by the accessory olfactory system (AOS). We previously found that gonadectomized male and female rats treated in adulthood with testosterone propionate (TP) showed equivalent Fos responses in the AOS to odors derived from estrous females. Likewise, in contrast with numerous other mammalian species, gonadectomized female rats show surprisingly high levels of male-typical mounting beh...

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

    Science.gov (United States)

    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.

  6. Global Histone H4 Acetylation in the Olfactory Bulb of Lactating Rats with Different Patterns of Maternal Behavior.

    Science.gov (United States)

    de Moura, Ana Carolina; da Silva, Ivy Reichert Vital; Reinaldo, Gustavo; Dani, Caroline; Elsner, Viviane Rostirola; Giovenardi, Márcia

    2016-10-01

    In rats, variations in the levels of neuromodulatory molecules and in the expression of their receptors are observed during pregnancy and postpartum. These changes may contribute to the development and management of maternal behavior. The frequency of licking the pups is used to evaluate maternal care, having mothers with low licking (LL) and high licking (HL) frequencies. Previously, we found that HL had increased levels of transcriptional expression of the receptors for serotonin (HTR1a, HTR1b), estrogen (Erα), dopamine (D1a), and prolactin (Prlr) than LL in the olfactory bulb (OB); however, the molecular mechanisms behind this phenomenon are unknown. Since evidences pointed out that epigenetic marks, which may alter gene expression, are modulated by environmental factors such as exercise, diet, maternal care, and xenobiotic exposure, our objective was to verify the acetylation levels of histone-H4 in the OB of LL and HL rats. Maternal behavior was studied for the first 7 postpartum days. LL (n = 4) and HL (n = 5) mothers were selected according to the behavior of licking their pups. Acetylation levels of histone-H4 were determined using the Global Histone-H4 Acetylation Assay Kit and expressed as ng/mg protein (mean ± SD). Analysis revealed that HL (278.36 ± 68.95) had increased H4 acetylation levels than LL (183.24 ± 73.05; p = 0.045). The enhanced expression of the previously studied receptors in the OB could be related, at least in part, to the hyperacetylation status of histone-H4 here observed. Afterward, the modulation of histone acetylation levels could exert a pivotal role through molecular mechanisms involved in the different patterns of maternal behavior. PMID:26620050

  7. 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.

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

    OpenAIRE

    Alejandra Delgado; Erica H. Jaffé

    2011-01-01

    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. Th...

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

    Directory of Open Access Journals (Sweden)

    Pascaline Aimé

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

  10. 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

  11. 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.

  12. 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

  13. 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.

  14. 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

  15. 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

  16. 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.

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

    Science.gov (United States)

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

    1994-07-01

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

  18. 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…

  19. Increased doublecortin (DCX expression and incidence of DCX-immunoreactive multipolar cells in the subventricular zone-olfactory bulb system of suicides

    Directory of Open Access Journals (Sweden)

    Marissa E Maheu

    2015-06-01

    Full Text Available Postmortem studies have confirmed the occurrence of adult hippocampal neurogenesis in humans and implicated this process in antidepressant response, yet neurogenesis in other regions remains to be examined in the context of depression. Here we assess the extent of subventricular zone-olfactory bulb (SVZ-OB neurogenesis in adult humans having died by suicide. Protein expression of proliferative and neurogenic markers Sox2, proliferating cell nuclear antigen, and doublecortin (DCX were examined in postmortem SVZ and OB samples from depressed suicides and matched sudden-death controls. In the SVZ, DCX-immunoreactive (IR cells displayed phenotypes typical of progenitors, whereas in the olfactory tract (OT, they were multipolar with variable size and morphologies suggestive of differentiating cells. DCX expression was significantly increased in the OB of suicides, whereas SVZ DCX expression was higher among unmedicated, but not antidepressant-treated, suicides. Although very few DCX-IR cells were present in the control OT, they were considerably more common in suicides and correlated with OB DCX levels. Suicides also displayed higher DCX-IR process volumes. These results support the notion that OB neurogenesis is minimal in adult humans. They further indicate that the differentiation and migration of SVZ-derived neuroblasts may be altered in unmedicated suicides, leading to an accumulation of ectopically-differentiating cells in the OT. Normal SVZ DCX expression among suicides receiving antidepressants suggests a potentially novel mode of action of antidepressant medication. Given the modest group sizes and rarity of DCX-IR cells assessed here, a larger-scale characterization will be required before firm conclusions can be made regarding the identity of these cells.

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

    OpenAIRE

    Micheal J. Baum

    2012-01-01

    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 olf...

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

    OpenAIRE

    Baum, Michael J.

    2012-01-01

    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 (VNO) and their subsequent processing by a neural circuit that includes the accessory olfactory bulb (AOB), vomeronasal amygdala, and hypothalamus. Emperical data are reviewed in this paper that demonstrate the detection of volatile pheromones by t...

  2. 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.

  3. 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.

  4. Deletion of collapsin response mediator protein 4 results in abnormal layer thickness and elongation of mitral cell apical dendrites in the neonatal olfactory bulb.

    Science.gov (United States)

    Tsutiya, Atsuhiro; Watanabe, Hikaru; Nakano, Yui; Nishihara, Masugi; Goshima, Yoshio; Ohtani-Kaneko, Ritsuko

    2016-05-01

    Collapsin response mediator protein 4 (CRMP4), a member of the CRMP family, is involved in the pathogenesis of neurodevelopmental disorders such as schizophrenia and autism. Here, we first compared layer thickness of the olfactory bulb between wild-type (WT) and CRMP4-knockout (KO) mice. The mitral cell layer (MCL) was significantly thinner, whereas the external plexiform layer (EPL) was significantly thicker in CRMP4-KO mice at postnatal day 0 (PD0) compared with WTs. However, differences in layer thickness disappeared by PD14. No apoptotic cells were found in the MCL, and the number of mitral cells (MCs) identified with a specific marker (i.e. Tbx21 antibody) did not change in CRMP4-KO neonates. However, DiI-tracing showed that the length of mitral cell apical dendrites was greater in CRMP4-KO neonates than in WTs. In addition, expression of CRMP4 mRNA in WT mice was most abundant in the MCL at PD0 and decreased afterward. These results suggest that CRMP4 contributes to dendritic elongation. Our in vitro studies showed that deletion or knockdown of CRMP4 resulted in enhanced growth of MAP2-positive neurites, whereas overexpression of CRMP4 reduced their growth, suggesting a new role for CRMP4 as a suppressor of dendritic elongation. Overall, our data suggest that disruption of CRMP4 produces a temporary alteration in EPL thickness, which is constituted mainly of mitral cell apical dendrites, through the enhanced growth of these dendrites. PMID:26739921

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

    International Nuclear Information System (INIS)

    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

  6. 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.

  7. Prolactin administration during early postnatal life decreases hippocampal and olfactory bulb neurogenesis and results in depressive-like behavior in adulthood.

    Science.gov (United States)

    Lajud, Naima; Gonzalez-Zapien, Rubén; Roque, Angélica; Tinajero, Eréndira; Valdez, Juan José; Clapp, Carmen; Torner, Luz

    2013-11-01

    Tight regulation of hormone and neurochemical milieu during developmental periods is critical for adequate physiological functions. For instance, activation of peptide systems during early life stress induces morphological changes in the brain resulting in depression and anxiety disorders. Prolactin (PRL) exerts different actions within the brain; it regulates neurogenesis and modulates neuroendocrine functions in the adult. However, PRL effects during early postnatal life are hardly known. Therefore, we examined whether neonatal administration of PRL influences cell survival in the hippocampal dentate gyrus (DG) and in the olfactory bulb (OB) and whether such influence results in behavioral consequences in adulthood. PRL-treated rat pups (13 mg/kg; PND1 to PND14), injected with BrdU at postnatal day 5 (PND5), showed a decrease in the density of DG BrdU/DCX and BrdU/NeuN-positive cells that survive at PND15. Similarly, PRL treatment decreased the density of BrdU+ cells in the OB compared with VEH. Fluorojade B analysis showed no significant changes in the amount of cell death in the DG between the groups. Postnatal PRL administration induced a passive coping strategy in the forced swimming test in male and female adult rats when compared with control and vehicle groups. Corticosterone endogenous levels at PND12 were not affected by PRL or VEH treatment. Altogether, these results suggest that opposed to its effects in the adult, postnatal PRL treatment affects neurogenesis and results in psychopathology later in life. High PRL levels, as observed in neonates under several pathological states, might contribute to detrimental effects on the developing brain.

  8. Expression of corticosteroid binding globulin in the rat olfactory system.

    Science.gov (United States)

    Dölz, Wilfried; Eitner, Annett; Caldwell, Jack D; Jirikowski, Gustav F

    2013-05-01

    Glucocorticoids are known to act on the olfactory system although their mode of action is still unclear since nuclear glucocorticoid receptors are mostly absent in the olfactory mucosa. In this study we used immunocytochemistry, in situ hybridization, and RT-PCR to study the expression and distribution of corticosteroid binding globulin (CBG) in the rat olfactory system. Mucosal goblet cells could be immunostained for CBG. Nasal secretion contained measurable amounts of CBG suggesting that CBG is liberated. CBG immunoreactivity was localized in many of the basal cells of the olfactory mucosa, while mature sensory cells contained CBG only in processes as determined by double immunostaining with the olfactory marker protein OMP. This staining was most pronounced in the vomeronasal organ (VNO). The appearance of CBG in the non-sensory and sensory parts of the VNO and in nerve terminals in the accessory bulb indicated axonal transport. Portions of the periglomerular cells, the mitral cells and the tufted cells were also CBG positive. CBG encoding transcripts were confirmed by RT-PCR in homogenates of the olfactory mucosa and VNO. Olfactory CBG may be significant for uptake, accumulation and transport of glucocorticoids, including aerosolic cortisol. PMID:23141917

  9. 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.

  10. 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.

  11. 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

  12. 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

  13. 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…

  14. 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.

  15. Phylogenic studies on the olfactory system in vertebrates.

    Science.gov (United States)

    Taniguchi, Kazuyuki; Taniguchi, Kazumi

    2014-06-01

    The olfactory receptor organs and their primary centers are classified into several types. The receptor organs are divided into fish-type olfactory epithelium (OE), mammal-type OE, middle chamber epithelium (MCE), lower chamber epithelium (LCE), recess epithelium, septal olfactory organ of Masera (SO), mammal-type vomeronasal organ (VNO) and snake-type VNO. The fish-type OE is observed in flatfish and lungfish, while the mammal-type OE is observed in amphibians, reptiles, birds and mammals. The MCE and LCE are unique to Xenopus and turtles, respectively. The recess epithelium is unique to lungfish. The SO is observed only in mammals. The mammal-type VNO is widely observed in amphibians, lizards and mammals, while the snake-type VNO is unique to snakes. The VNO itself is absent in turtles and birds. The mammal-type OE, MCE, LCE and recess epithelium seem to be descendants of the fish-type OE that is derived from the putative primitive OE. The VNO may be derived from the recess epithelium or fish-type OE and differentiate into the mammal-type VNO and snake-type VNO. The primary olfactory centers are divided into mammal-type main olfactory bulbs (MOB), fish-type MOB and mammal-type accessory olfactory bulbs (AOB). The mammal-type MOB first appears in amphibians and succeeds to reptiles, birds and mammals. The fish-type MOB, which is unique to fish, may be the ancestor of the mammal-type MOB. The mammal-type AOB is observed in amphibians, lizards, snakes and mammals and may be the remnant of the fish-type MOB. PMID:24531771

  16. 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.

  17. Roles of the main olfactory and vomeronasal systems in the detection of androstenone in inbred strains of mice

    Directory of Open Access Journals (Sweden)

    Vera V. VOZNESSENSKAYA, Maria A.KLYUCHNIKOVA, Charles J. WYSOCKI

    2010-12-01

    Full Text Available We investigated the role of the main olfactory and accessory olfactory systems (MOS and AOS respectively in the detection of androstenone. We used the following experimental approaches: behavioral, surgical removal of the vomeronasal organ (VNX followed by histochemical verification and Fos immunohistochemistry. Using a Y-maze paradigm we estimated sensitivity of NZB/B1NJ and CBA/J mice to androstenone. CBA mice were 2,000-fold more sensitive to androstenone than NZB mice. VNX caused a 4- to16-fold decrease in sensitivity to androstenone in highly-sensitive CBA mice, but did not affect thresholds in NZB mice. Results indicate the involvement of the MOS and AOS in the detection of androstenone. We observed a specific pattern of Fos-positive cells in the main olfactory bulb of CBA mice but not in NZB mice subsequent to exposure of mice to androstenone; the compound activated cells in the accessory olfactory bulb in both strains of mice, indicating the involvement of the vomeronasal organ. Patterns of Fos-positive cells in the vomeronasal organ were recorded subsequent to exposure to androstenone. Fos-positive receptor cells in the vomeronasal organ of CBA and NZB mice were different, in CBA mice Fos-positive cells were noted in both the basal and apical zones, however, in NZB mice activation was observed only in the apical zone [Current Zoology 56 (6: 813–818, 2010].

  18. Anterior olfactory organ removal produces anxiety-like behavior and increases spontaneous neuronal firing rate in basal amygdala.

    Science.gov (United States)

    Contreras, Carlos M; Gutiérrez-García, Ana G; Molina-Jiménez, Tania

    2013-09-01

    Some chemical cues may produce signs of anxiety and fear mediated by amygdala nuclei, but unknown is the role of two anterior olfactory epithelial organs, the septal and vomeronasal organs (SO-VNOs). The effects of SO-VNO removal were explored in different groups of Wistar rats using two complementary approaches: (i) the assessment of neuronal firing rate in basal and medial amygdala nuclei and (ii) behavioral testing. Fourteen days after SO-VNO removal, spontaneous activity in basal and medial amygdala nuclei in one group was determined using single-unit extracellular recordings. A separate group of rats was tested in the elevated plus maze, social interaction test, and open field test. Compared with sham-operated and intact control rats, SO-VNO removal produced a higher neuronal firing rate in the basal amygdala but not medial amygdala. In the behavioral tests, SO-VNO removal increased signs of anxiety in the elevated plus maze, did not alter locomotion, and increased self-directed behavior, reflecting anxiety-like behavior. Histological analysis showed neuronal destruction in the accessory olfactory bulb but not anterior olfactory nucleus in the SO-VNO group. The present results suggest the participation of SO-VNO/accessory olfactory bulb/basal amygdala relationships in the regulation of anxiety through a process of disinhibition. PMID:23721965

  19. Anterior olfactory organ removal produces anxiety-like behavior and increases spontaneous neuronal firing rate in basal amygdala.

    Science.gov (United States)

    Contreras, Carlos M; Gutiérrez-García, Ana G; Molina-Jiménez, Tania

    2013-09-01

    Some chemical cues may produce signs of anxiety and fear mediated by amygdala nuclei, but unknown is the role of two anterior olfactory epithelial organs, the septal and vomeronasal organs (SO-VNOs). The effects of SO-VNO removal were explored in different groups of Wistar rats using two complementary approaches: (i) the assessment of neuronal firing rate in basal and medial amygdala nuclei and (ii) behavioral testing. Fourteen days after SO-VNO removal, spontaneous activity in basal and medial amygdala nuclei in one group was determined using single-unit extracellular recordings. A separate group of rats was tested in the elevated plus maze, social interaction test, and open field test. Compared with sham-operated and intact control rats, SO-VNO removal produced a higher neuronal firing rate in the basal amygdala but not medial amygdala. In the behavioral tests, SO-VNO removal increased signs of anxiety in the elevated plus maze, did not alter locomotion, and increased self-directed behavior, reflecting anxiety-like behavior. Histological analysis showed neuronal destruction in the accessory olfactory bulb but not anterior olfactory nucleus in the SO-VNO group. The present results suggest the participation of SO-VNO/accessory olfactory bulb/basal amygdala relationships in the regulation of anxiety through a process of disinhibition.

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

    NARCIS (Netherlands)

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

    2004-01-01

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

  1. 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

  2. the olfactory bulbectomized mouse

    OpenAIRE

    Fink, Katharina

    2010-01-01

    The bilateral ectomy of the olfactory bulb in rats and mice is an accepted animal model of depression. Because of its good predictive validity it is used to develop new antidepressants and to prove their effectiveness. After the olfactory bulbectomy, the animals show a certain pattern of changes in behaviour and in neurochemical, neuroendocrinological and neuroimmunological parameters. The leading parameter for the changes of behaviour in these animals is the locomotoric hyperactivity in the ...

  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 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.

  5. 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.

  6. 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.

  7. 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…

  8. 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.

  9. 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.

  10. 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…

  11. Experimental study on exnotransplantation of microencapsulated olfactory bulb combined with L-NAME for the treatment of spinal cord injury%微囊化异种嗅球组织移植联合L-NAME治疗脊髓损伤的实验研究

    Institute of Scientific and Technical Information of China (English)

    王航辉; 白延斌; 李小记; 王璐; 朱文侠; 韩振奎; 赵琳

    2011-01-01

    目的 探讨微囊化异种嗅球组织移植联合L-NAME对脊髓继发性损伤的治疗保护作用及机制.方法 健康SD大鼠,随机分为对照组、微囊化兔嗅球组织移植组、微囊化异种嗅球组织移植联合LNAME治疗组,损伤组又设1、3、7、14、28d 5个时相点,紫外分光光度计检测脊髓伊文氏蓝含量,干湿重法测定脊髓组织含水量;免疫组织化学技术检测MMP-9的表达;神经功能评分法(BBB法)评价大鼠术后运动功能的恢复情况.结果 脊髓损伤后脊髓伊文氏蓝含量增加、脊髓血管源性水肿、MMP-9表达上调,大鼠的运动功能缺失,经微囊化异种嗅球组织移植联合L-NAME治疗后血脊髓屏障通透性降低、水肿明显减轻、MMP-9表达下调,大鼠的运动功能恢复.结论 微囊化异种嗅球组织移植对脊髓继发性损伤有较好的疗效,联合应用嗅球组织细胞和L-NAME在脊髓损伤修复治疗中具有协同作用.%Objective To explore the protective effects and mechanism of exnotransplantation of microencapsulated olfactory bulb combined with L-NAME in rats at the early stages of spinal cord injury. Methods Healthy SD rats were divided into three groups as following: injury control group, microencapsulated transplantation of rabbit olfactory bulb cells group, microencapsulated transplantation of rabbit olfactory bulb cells combined with L-NAME group, the later two groups were quantified at 1, 3,7, 14, and 28 d post spinal cord injury. Spinal Evans blue content was examined with the ultraviolet spectrophotometer; Spinal cord water content was detected by caculating dry/wet weight. The change of MMP-9 expression after spinal cord injury was determined by immunohistochemical method. BBB score was designed to assess its behavioral ability. Results Evans blue content and expression of MMP-9 were significantly were significantly increased, vasogenic spinal cord edema, and loss of motor function in rats after spinal cord irjury

  12. Neurotoxic Effects of Dichlorophenyl Methylsulphones Related to Olfactory Mucosal Lesions

    OpenAIRE

    Carlsson, Carina

    2003-01-01

    This thesis deals with the highly potent olfactory mucosa toxicant 2,6-dichlorophenyl methylsulphone (2,6-diClPh-MeSO2) and its non-toxic 2,5-chlorinated isomer (2,5-diClPh-MeSO2). In mice, both substances bind firmly in the olfactory mucosa and the olfactory bulb, which are important components of the sensory system. The 2,6-isomer induces olfactory mucosal necrosis with permanent loss of olfactory neuroepithelium and olfactory nerves. A major objective was to clarify the cause of this isome...

  13. CNPase Expression in Olfactory Ensheathing Cells

    Directory of Open Access Journals (Sweden)

    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.

  14. 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.

  15. 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.

  16. 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

  17. Odorant Category Profile Selectivity of Olfactory Cortex

    OpenAIRE

    Yoshida, Ikue; Mori, Kensaku

    2007-01-01

    The olfactory cortex receives converging axonal inputs from many mitral and tufted cells in the olfactory bulb. Recent studies indicate that single cortical neurons integrate signals from diverse odorants. However, there remains a basic question, namely, the signals from which kinds of odorants are integrated by the individual cortical neurons? The present study examined the possibility that some cortical neurons integrate signals from distinct component odorants of natural foods because indi...

  18. 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

  19. 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.

  20. Physiological and morphological characterization of honeybee olfactory neurons combining electrophysiology, calcium imaging and confocal microscopy

    OpenAIRE

    Galizia, Cosmas Giovanni; Kimmerle, B.

    2004-01-01

    The insect antennal lobe is the first brain structure to process olfactory information. Like the vertebrate olfactory bulb the antennal lobe is substructured in olfactory glomeruli. In insects, glomeruli can be morphologically identified, and have characteristic olfactory response profiles. Local neurons interconnect glomeruli, and output (projection) neurons project to higher-order brain centres. The relationship between their elaborate morphology and their physiology is not understood. We r...

  1. 微囊化异种嗅球组织移植联合β-七叶皂甙钠对脊髓损伤大鼠血脊髓屏障功能和血管源性脊髓水肿的影响%Effects of exnotransplantation of microencapsulated olfactory bulb combined with β-aescinate sodium on blood-spinal barrier function and vasogenic spinal cord edema in spinal cord injury rats.

    Institute of Scientific and Technical Information of China (English)

    王航辉; 张博; 朱文侠; 李小记; 韩振奎; 王璐; 赵琳; 刘伯锋

    2011-01-01

    Objective To explore the protective effects and mechanism of exnotransplantation of microencapsulated olfactory bulb combined with β-aescinate sodium in rats at the early stages of spinal cord injury.Methods Healthy SD rats were divided into three groups as following: injury control group, microencapsulated transplantation of rabbit olfactory bulb cells group, microencapsulated transplantation of rabbit olfactory bulb cells combined with β-aescinate sodium group, the later two groups were quantified at 1,3, 7, 14, and 28 d post spinal cord injury.Spinal Evans blue content was examined with the ultraviolet spectrophotometer; Spinal cord water content was detected by caculating dry/wet weight.The ultrastructural change of blood-spinal barrier was observed by transmission electron microscope.BBB score was designed to assess its behavioral ability.Results Evans blue content were significantly increased, vasogenic spinal cord edema, and loss of motor function in rats after spinal cord injury.Permeability of blood-spinal barrier and vasogenic spinal cord edema were obviously decreased, motor function was recoveried in rats after they were treated with microencapsulated transplantation of rabbit olfactory bulb cells combined with β-aescinate sodium.Conclusion Exnotransplantation of microencapsulated strategy of olfactory ensheating cells was effective in the repair of spinal cord injury in some extent.There may be a synergistic effect between olfactory ensheating cells and β-aescinate sodium.%目的 旨在探讨微囊化异种嗅球组织移植联合β-七叶皂甙钠对脊髓继发性损伤的治疗保护作用及机制.方法 健康SD大鼠,随机分为损伤对照组、微囊化兔嗅球组织移植组、微囊化兔嗅球组织移植联合β-七叶皂甙钠治疗组,损伤组又设1、3、7、14、28d 5个时相点,紫外分光光度计检测脊髓伊文氏蓝含量,干湿重法测定脊髓组织含水量;同时电镜观察血脊髓屏障的变化;神经功能评

  2. 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. PMID:11314863

  3. 菜花原矛头蝮嗅觉系统和犁鼻系统的显微结构%The microstructure of olfactory and vomeronasal systems in snake, Protobothrops jerdonii

    Institute of Scientific and Technical Information of China (English)

    王宏元; 柴丽红; 王晓雯; 李忻怡

    2011-01-01

    采用组织学方法观察了菜花原矛头蝮(Protobothrops jerdonii)的嗅觉系统和犁鼻系统.结果表明,嗅器位于嗅囊的背侧,犁鼻器则位于嗅器的腹内侧.嗅器的上皮分化为嗅上皮和呼吸上皮,嗅上皮的基底层有Bowman's腺,呼吸上皮中具有大量的杯状细胞.犁鼻器基底层未发现犁鼻腺.嗅球和副嗅球呈典型的板层构筑结构.推测菜花原矛头蝮嗅器内嗅上皮和呼吸上皮完全分开有利于背侧嗅上皮俘获气味信号,腹侧呼吸上皮参与呼吸作用.虽然菜花原矛头蝮等蛇类的犁鼻器缺少犁鼻腺,但是其眼眶周围的哈氏腺和口腔内的唾液腺可以代偿犁鼻腺机能.%The olfactory organ and vomeronasal system in snake, Protobothrops jerdonii, were investigated under the microscope. The results showed that the olfactory organ lies in the dorsal and the vomeronasal organ is in the ventral portion of the nose cavity. The epithelium of the olfactory cavity is divided into the two segments: olfactory epithelium and respiratory epithelium.Bowman's gland in the olfactory epithelium is present and goblets cells occur in the respiratory epithelium. Vomeronasal gland is not found in the vomeronasal organ. The olfactory bulb and accessory olfactory bulb are typical laminar pattern. Subdivision of dorsal olfactory epithelium and ventral respiratory epithelium in snake may be beneficial to that the olfactory epithelium capture odour and respiratory epithelium take party into the respiratory. In addition, the vomeronasal organ in snake lacks vomeronasal glands, but the harderian gland and the salivary glands compensate lack of the vomeronasal gland.

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

    International Nuclear Information System (INIS)

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

  5. Wiring Switches to Light Bulbs

    CERN Document Server

    Buckley, Stephen M

    2011-01-01

    Given n buttons and n bulbs so that the ith button toggles the ith bulb and at most two other bulbs, we compute the sharp lower bound on the number of bulbs that can be lit regardless of the action of the buttons.

  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. Oxytocin Enhances Social Recognition by Modulating Cortical Control of Early Olfactory Processing.

    Science.gov (United States)

    Oettl, Lars-Lennart; Ravi, Namasivayam; Schneider, Miriam; Scheller, Max F; Schneider, Peggy; Mitre, Mariela; da Silva Gouveia, Miriam; Froemke, Robert C; Chao, Moses V; Young, W Scott; Meyer-Lindenberg, Andreas; Grinevich, Valery; Shusterman, Roman; Kelsch, Wolfgang

    2016-05-01

    Oxytocin promotes social interactions and recognition of conspecifics that rely on olfaction in most species. The circuit mechanisms through which oxytocin modifies olfactory processing are incompletely understood. Here, we observed that optogenetically induced oxytocin release enhanced olfactory exploration and same-sex recognition of adult rats. Consistent with oxytocin's function in the anterior olfactory cortex, particularly in social cue processing, region-selective receptor deletion impaired social recognition but left odor discrimination and recognition intact outside a social context. Oxytocin transiently increased the drive of the anterior olfactory cortex projecting to olfactory bulb interneurons. Cortical top-down recruitment of interneurons dynamically enhanced the inhibitory input to olfactory bulb projection neurons and increased the signal-to-noise of their output. In summary, oxytocin generates states for optimized information extraction in an early cortical top-down network that is required for social interactions with potential implications for sensory processing deficits in autism spectrum disorders. PMID:27112498

  8. The Laser Accessory Market

    Science.gov (United States)

    Desai, Ashvin

    1988-09-01

    Wandering through the exhibit hall yesterday, I noticed that if you look at the laser companies and if you look at the accessory companies, there are pretty much the same number of accessory booths as well as the laser companies. There was one difference. Laser company booths are all sexy looking, very flashy, big booths. Whereas if you look at the accessories booths, they were small, not so prominent.

  9. 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.

  10. 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

  11. Illuminating Physics with Light Bulbs.

    Science.gov (United States)

    Leff, Harvey S.

    1990-01-01

    Presents ideas on how common household light bulbs can be used to develop interest in learning physics. Focuses on supermarket data taking and analyses, filament temperatures, detective work with three-way bulbs, and lifetime statistics. (YP)

  12. Tract-tracing study of the extrabulbar olfactory projections in the brain of some teleosts.

    Science.gov (United States)

    D'aniello, Biagio; Luongo, Luciano; Rastogi, Rakesh K; Di Meglio, Maria; Pinelli, Claudia

    2015-04-01

    The extrabulbar olfactory projections (EBOP) is a collection of nerve fibers that originate from primary olfactory receptor neurons. These fibers penetrate into the brain, bypassing the olfactory bulbs (OBs). While the presence of an EBOP has been well established in teleosts, here we morphologically characterize the EBOP structure in four species each with a different morphological relationship of OB with the ventral telencephalic area. Tract-tracing methods (carbocyanine DiI/DIA and biocytin) were used. FMRFamide immunoreactive nervus terminalis (NT) components were also visualized to define any neuroanatomical relationship between the NT and EBOP. Unilateral DiI/DiA application to the olfactory chamber stained the entire olfactory epithelium, olfactory nerve fibers, and ipsilateral olfactory bulb. Labeled primary olfactory fibers running ventromedially as extrabulbar primary olfactory projections reached various regions of the secondary prosencephalon. Only in Moenkhausia sanctaefilomenae (no olfactory peduncle) did lipophilic tracer-labeled fibers reach the ipsilateral mesencephalon. The combination of tracing techniques and FMRFamide immunohistochemistry revealed a substantial overlap of the label along the olfactory pathways as well as in the anterior secondary prosencephalon. However, FMRFamide immunoreactivity was never colocalized in the same cellular or fiber component as visualized using tracer molecules. Our results showed a certain uniformity in the neuroanatomy and extension of EBOP in all four species, independent of the pedunculate feature of the OBs. The present study also provided additional evidence to support the view that EBOP and FMRFamide immunoreactive components of the NT are separate anatomical entities. PMID:25663434

  13. 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.

  14. Small Engine & Accessory Test Area

    Data.gov (United States)

    Federal Laboratory Consortium — The Small Engine and Accessories Test Area (SEATA) facilitates testaircraft starting and auxiliary power systems, small engines and accessories. The SEATA consists...

  15. A lifetime of neurogenesis in the olfactory system.

    Science.gov (United States)

    Brann, Jessica H; Firestein, Stuart J

    2014-01-01

    Neurogenesis continues well beyond embryonic and early postnatal ages in three areas of the nervous system. The subgranular zone supplies new neurons to the dentate gyrus of the hippocampus. The subventricular zone supplies new interneurons to the olfactory bulb, and the olfactory neuroepithelia generate new excitatory sensory neurons that send their axons to the olfactory bulb. The latter two areas are of particular interest as they contribute new neurons to both ends of a first-level circuit governing olfactory perception. The vomeronasal organ and the main olfactory epithelium comprise the primary peripheral olfactory epithelia. These anatomically distinct areas share common features, as each exhibits extensive neurogenesis well beyond the juvenile phase of development. Here we will discuss the effect of age on the structural and functional significance of neurogenesis in the vomeronasal and olfactory epithelia, from juvenile to advanced adult ages, in several common model systems. We will next discuss how age affects the regenerative capacity of these neural stem cells in response to injury. Finally, we will consider the integration of newborn neurons into an existing circuit as it is modified by the age of the animal. PMID:25018692

  16. A lifetime of neurogenesis in the olfactory system

    Directory of Open Access Journals (Sweden)

    Jessica H. Brann

    2014-06-01

    Full Text Available Neurogenesis continues well beyond embryonic and early postnatal ages in three areas of the nervous system. The subgranular zone supplies new neurons to the dentate gyrus of the hippocampus. The subventricular zone supplies new interneurons to the olfactory bulb, and the olfactory neuroepithelia generates new excitatory sensory neurons that send their axons to the olfactory bulb. The latter two areas are of particular interest as they contribute new neurons to both ends of a first-level circuit governing olfactory perception. The vomeronasal organ and the main olfactory epithelium comprise the primary peripheral olfactory epithelia. These anatomically distinct areas share common features, as each exhibits extensive neurogenesis well beyond the juvenile phase of development. Here we will discuss the effect of age on the structural and functional significance of neurogenesis in the vomeronasal and olfactory epithelia, from juvenile to advanced adult ages, in several common model systems. We will next discuss how age affects the regenerative capacity of these neural stem cells in response to injury. Finally, we will consider the integration of newborn neurons into an existing circuit as it is modified by the age of the animal.

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

    OpenAIRE

    Laís Soares Rodrigues; Adriano eTarga; Ana Carolina Duarte Noseda; Aurich, Mariana F.; Cláudio eDa Cunha; Marcelo M. S. Lima

    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). 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 we...

  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. Human Neural Cells Transiently Express Reelin during Olfactory Placode Development

    Science.gov (United States)

    Antal, M. Cristina; Samama, Brigitte; Ghandour, M. Said; Boehm, Nelly

    2015-01-01

    Reelin, an extracellular glycoprotein is essential for migration and correct positioning of neurons during development. Since the olfactory system is known as a source of various migrating neuronal cells, we studied Reelin expression in the two chemosensory olfactory systems, main and accessory, during early developmental stages of human foetuses/embryos from Carnegie Stage (CS) 15 to gestational week (GW) 14. From CS 15 to CS 18, but not at later stages, a transient expression of Reelin was detected first in the presumptive olfactory and then in the presumptive vomeronasal epithelium. During the same period, Reelin-positive cells detach from the olfactory/vomeronasal epithelium and migrate through the mesenchyme beneath the telencephalon. Dab 1, an adaptor protein of the Reelin pathway, was simultaneously expressed in the migratory mass from CS16 to CS17 and, at later stages, in the presumptive olfactory ensheathing cells. Possible involvements of Reelin and Dab 1 in the peripheral migrating stream are discussed. PMID:26270645

  1. Nectin-1 spots regulate the branching of olfactory mitral cell dendrites.

    Science.gov (United States)

    Fujiwara, Takeshi; Inoue, Takahito; Maruo, Tomohiko; Rikitake, Yoshiyuki; Ieki, Nao; Mandai, Kenji; Kimura, Kazushi; Kayahara, Tetsuro; Wang, Shujie; Itoh, Yu; Sai, Kousyoku; Mori, Masahiro; Mori, Kensaku; Takai, Yoshimi; Mizoguchi, Akira

    2015-09-01

    Olfactory mitral cells extend lateral secondary dendrites that contact the lateral secondary and apical primary dendrites of other mitral cells in the external plexiform layer (EPL) of the olfactory bulb. The lateral dendrites further contact granule cell dendrites, forming dendrodendritic reciprocal synapses in the EPL. These dendritic structures are critical for odor information processing, but it remains unknown how they are formed. We recently showed that the immunoglobulin-like cell adhesion molecule nectin-1 constitutes a novel adhesion apparatus at the contacts between mitral cell lateral dendrites, between mitral cell lateral and apical dendrites, and between mitral cell lateral dendrites and granule cell dendritic spine necks in the deep sub-lamina of the EPL of the developing mouse olfactory bulb and named them nectin-1 spots. We investigated here the role of the nectin-1 spots in the formation of dendritic structures in the EPL of the mouse olfactory bulb. We showed that in cultured nectin-1-knockout mitral cells, the number of branching points of mitral cell dendrites was reduced compared to that in the control cells. In the deep sub-lamina of the EPL in the nectin-1-knockout olfactory bulb, the number of branching points of mitral cell lateral dendrites and the number of dendrodendritic reciprocal synapses were reduced compared to those in the control olfactory bulb. These results indicate that the nectin-1 spots regulate the branching of mitral cell dendrites in the deep sub-lamina of the EPL and suggest that the nectin-1 spots are required for odor information processing in the olfactory bulb. PMID:26169026

  2. 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.

  3. Loss of STOP protein impairs peripheral olfactory neurogenesis.

    Directory of Open Access Journals (Sweden)

    Karelle Benardais

    Full Text Available BACKGROUND: STOP (Stable Tubulin-Only Polypeptide null mice show behavioral deficits, impaired synaptic plasticity, decrease in synaptic vesicular pools and disturbances in dopaminergic transmission, and are considered a neurodevelopmental model of schizophrenia. Olfactory neurons highly express STOP protein and are continually generated throughout life. Experimentally-induced loss of olfactory neurons leads to epithelial regeneration within two months, providing a useful model to evaluate the role played by STOP protein in adult olfactory neurogenesis. METHODOLOGY/PRINCIPAL FINDINGS: Immunocytochemistry and electron microscopy were used to study the structure of the glomerulus in the main olfactory bulb and neurogenesis in the neurosensorial epithelia. In STOP null mice, olfactory neurons showed presynaptic swellings with tubulovesicular profiles and autophagic-like structures. In olfactory and vomeronasal epithelia, there was an increase in neurons turnover, as shown by the increase in number of proliferating, apoptotic and immature cells with no changes in the number of mature neurons. Similar alterations in peripheral olfactory neurogenesis have been previously described in schizophrenia patients. In STOP null mice, regeneration of the olfactory epithelium did not modify these anomalies; moreover, regeneration resulted in abnormal organisation of olfactory terminals within the olfactory glomeruli in STOP null mice. CONCLUSIONS/SIGNIFICANCE: In conclusion, STOP protein seems to be involved in the establishment of synapses in the olfactory glomerulus. Our results indicate that the olfactory system of STOP null mice is a well-suited experimental model (1 for the study of the mechanism of action of STOP protein in synaptic function/plasticity and (2 for pathophysiological studies of the mechanisms of altered neuronal connections in schizophrenia.

  4. 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...

  5. 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.

  6. Olfactory lateralization in homing pigeons: initial orientation of birds receiving a unilateral olfactory input.

    Science.gov (United States)

    Gagliardo, Anna; Pecchia, Tommaso; Savini, Maria; Odetti, Francesca; Ioalè, Paolo; Vallortigara, Giorgio

    2007-03-01

    It has been shown that homing pigeons (Columba livia) rely on olfactory cues to navigate from unfamiliar locations. In fact, the integrity of the olfactory system, from the olfactory mucosa to the piriform cortex, is required for pigeons to navigate over unfamiliar areas. Recently it has been shown that there is a functional asymmetry in the piriform cortex, with the left piriform cortex more involved in the use of the olfactory navigational map than the right piriform cortex. To investigate further the lateralization of the olfactory system in relation to navigational processes in carrier pigeons, we compared their homing performance after either their left or the right nostril was plugged. Contrary to our expectations, we observed an impairment in the initial orientation of the pigeons with their right nostril plugged. However, both groups released with one nostril plugged tended to be poorer than control pigeons in their homing performance. The observed asymmetry in favour of the right nostril might be due to projections from the olfactory bulbs to the contralateral globus pallidum, a structure involved in motor responses. PMID:17425577

  7. 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.

  8. The painful accessory navicular

    International Nuclear Information System (INIS)

    The accessory navicular is usually considered a normal anatomic and roentgenographic variant. The term may refer to two distinct patterns. First, a sesamoid bone may be present within the posterior tibial tendon (Type 1); this is anatomically separate from the navicular. Second, an accessory ossification center may be medial to the navicular (Type 2). During postnatal development this is within a cartilaginous mass that is continuous with the cartilage of the navicular. At skeletal maturity the accessory center usually fuses with the navicular to form a curvilinear bone. The Type 2 pattern may be associated with a painful foot, particularly in the athletic adolescent, and should not be arbitrarily dismissed as a roentgenologic variant in the symptomatic patient. The clinical, radiologic, pathologic, and surgical findings in ten cases are reviewed. Roentgenographically the ossicle is triangular or heartshaped. sup(99m)Tc MDP imaging may be of value when the significance of the ossicle is uncertain. Even when the roentgenographic variant is bilateral, increased radionuclide activity occurs only on the symptomatic side. Histologic examination of surgically excised specimens reveals inflammatory chondro-osseous changes in the navicular-accessory navicular synchondrosis compatible with chronic trauma and stress fracture. Nonsurgical treatment with orthotics or cast immobilization produces variable results and resection of the accessory navicular may be the treatment of choice. (orig.)

  9. Olfactory signaling in insects.

    Science.gov (United States)

    Wicher, Dieter

    2015-01-01

    The detection of volatile chemical information in insects is performed by three types of olfactory receptors, odorant receptors (ORs), specific gustatory receptor (GR) proteins for carbon dioxide perception, and ionotropic receptors (IRs) which are related to ionotropic glutamate receptors. All receptors form heteromeric assemblies; an OR complex is composed of an odor-specific OrX protein and a coreceptor (Orco). ORs and GRs have a 7-transmembrane topology as for G protein-coupled receptors, but they are inversely inserted into the membrane. Ligand-gated ion channels (ionotropic receptors) and ORs operate as IRs activated by volatile chemical cues. ORs are evolutionarily young receptors, and they first appear in winged insects and seem to be evolved to allow an insect to follow sparse odor tracks during flight. In contrast to IRs, the ORs can be sensitized by repeated subthreshold odor stimulation. This process involves metabotropic signaling. Pheromone receptors are especially sensitive and require an accessory protein to detect the lipid-derived pheromone molecules. Signaling cascades involved in pheromone detection depend on intensity and duration of stimuli and underlie a circadian control. Taken together, detection and processing of volatile information in insects involve ionotropic as well as metabotropic mechanisms. Here, I review the cellular signaling events associated with detection of cognate ligands by the different types of odorant receptors.

  10. 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.

  11. Shedding Some Light on Fluorescent Bulbs.

    Science.gov (United States)

    Guilbert, Nicholas R.

    1996-01-01

    Explores some of the principles behind the working of fluorescent bulbs using a specially prepared fluorescent bulb with the white inner fluorescent coating applied along only half its length. Discusses the spectrum, the bulb plasma, and light production. (JRH)

  12. Closed suction drain with bulb

    Science.gov (United States)

    ... tube. Start where it comes out of your body and move toward the drainage bulb. This is called "stripping" the drain. Release your fingers from the end of the drain where it comes out of your body and then release the end near the bulb. ...

  13. Bilateral accessory thoracodorsal artery.

    Science.gov (United States)

    Natsis, Konstantinos; Totlis, Trifon; Tsikaras, Prokopios; Skandalakis, Panagiotis

    2006-09-01

    The subscapular artery arises from the third part of the axillary artery and gives off the circumflex scapular and the thoracodorsal arteries. Although anatomical variations of the axillary artery are very common, the existence of a unilateral accessory thoracodorsal artery has been described in the literature only once. There are no reports of bilateral accessory thoracodorsal artery, in the literature. In the present study, a bilateral accessory thoracodorsal artery, originating on either side of the third part of the axillary artery, is described in a 68-year-old female cadaver. All the other branches of the axillary artery had a typical origin, course, distribution and termination. This extremely rare anatomical variation apart from the anatomical importance also has clinical significance for surgeons in this area. Especially, during the dissection or mobilization of the latissimus dorsi that is partly used for coverage problems in many regions of the body and also in dynamic cardiomyoplasty, any iatrogenic injury of this accessory artery may result in ischemia and functional loss of the graft.

  14. 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.

  15. 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.

  16. 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.

  17. Aggressive behaviour and physiological responses to pheromones are strongly impaired in mice deficient for the olfactory G-protein -subunit G8.

    Science.gov (United States)

    Montani, Giorgia; Tonelli, Simone; Sanghez, Valentina; Ferrari, Pier Francesco; Palanza, Paola; Zimmer, Andreas; Tirindelli, Roberto

    2013-08-15

    Heterotrimeric G-proteins are critical players in the transduction mechanisms underlying odorant and pheromonal signalling. In the vomeronasal organ (VNO) of the adult mouse, two different G-protein complexes have been identified. Gαoβ2γ8 is preferentially expressed in the basal neurons and coexpresses with type-2 vomeronasal pheromone receptors (V2Rs) whereas Gαi2β2γ2 is found in the apical neurons and coexpresses with type-1 vomeronasal pheromone receptors (V1Rs). V2R-expressing neurons project to the posterior accessory olfactory bulb (AOB) whereas neurons expressing V1Rs send their axon to the anterior AOB. Gγ8 is also expressed in developing olfactory neurons where this protein is probably associated with Go. Here, we generated mice with a targeted deletion of the Gγ8 gene and investigated the behavioural effects and the physiological consequences of this mutation. Gγ8(-/-) mice show a normal development of the main olfactory epithelium; moreover, they do not display major deficits in odour perception. In contrast, the VNO undergoes a slow but remarkable loss of basal neurons starting from the fourth postnatal week, with a 40% reduction of cells at 2 months and 70% at 1 year. This loss is associated with a reduced early-gene expression in the posterior AOB of mice stimulated with pheromones. More interestingly, the Gγ8 deletion specifically leads to a reduced pheromone-mediated aggressiveness in both males and females, all other socio-sexual behaviours remaining unaltered. This study defines a specific role for Gγ8 in maintenance of the neuronal population of the VNO and in the mechanisms of pheromonal signalling that involve the aggressive behaviour towards conspecifics. PMID:23836683

  18. Diversity among principal and GABAergic neurons of the anterior olfactory nucleus

    OpenAIRE

    KAY, RACHEL B.; Brunjes, Peter C

    2014-01-01

    Understanding the cellular components of neural circuits is an essential step in discerning regional function. The anterior olfactory nucleus (AON) is reciprocally connected to both the ipsi- and contralateral olfactory bulb (OB) and piriform cortex (PC), and, as a result, can broadly influence the central processing of odor information. While both the AON and PC are simple cortical structures, the regions differ in many ways including their general organization, internal wiring and synaptic ...

  19. 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.

  20. Extinction reverses olfactory fear-conditioned increases in neuron number and glomerular size.

    Science.gov (United States)

    Morrison, Filomene G; Dias, Brian G; Ressler, Kerry J

    2015-10-13

    Although much work has investigated the contribution of brain regions such as the amygdala, hippocampus, and prefrontal cortex to the processing of fear learning and memory, fewer studies have examined the role of sensory systems, in particular the olfactory system, in the detection and perception of cues involved in learning and memory. The primary sensory receptive field maps of the olfactory system are exquisitely organized and respond dynamically to cues in the environment, remaining plastic from development through adulthood. We have previously demonstrated that olfactory fear conditioning leads to increased odorant-specific receptor representation in the main olfactory epithelium and in glomeruli within the olfactory bulb. We now demonstrate that olfactory extinction training specific to the conditioned odor stimulus reverses the conditioning-associated freezing behavior and odor learning-induced structural changes in the olfactory epithelium and olfactory bulb in an odorant ligand-specific manner. These data suggest that learning-induced freezing behavior, structural alterations, and enhanced neural sensory representation can be reversed in adult mice following extinction training.

  1. 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

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

    OpenAIRE

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

    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 dis...

  3. 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.

  4. The endocannabinoid system controls food intake via olfactory processes.

    Science.gov (United States)

    Soria-Gómez, Edgar; Bellocchio, Luigi; Reguero, Leire; Lepousez, Gabriel; Martin, Claire; Bendahmane, Mounir; Ruehle, Sabine; Remmers, Floor; Desprez, Tifany; Matias, Isabelle; Wiesner, Theresa; Cannich, Astrid; Nissant, Antoine; Wadleigh, Aya; Pape, Hans-Christian; Chiarlone, Anna Paola; Quarta, Carmelo; Verrier, Daniéle; Vincent, Peggy; Massa, Federico; Lutz, Beat; Guzmán, Manuel; Gurden, Hirac; Ferreira, Guillaume; Lledo, Pierre-Marie; Grandes, Pedro; Marsicano, Giovanni

    2014-03-01

    Hunger arouses sensory perception, eventually leading to an increase in food intake, but the underlying mechanisms remain poorly understood. We found that cannabinoid type-1 (CB1) receptors promote food intake in fasted mice by increasing odor detection. CB1 receptors were abundantly expressed on axon terminals of centrifugal cortical glutamatergic neurons that project to inhibitory granule cells of the main olfactory bulb (MOB). Local pharmacological and genetic manipulations revealed that endocannabinoids and exogenous cannabinoids increased odor detection and food intake in fasted mice by decreasing excitatory drive from olfactory cortex areas to the MOB. Consistently, cannabinoid agonists dampened in vivo optogenetically stimulated excitatory transmission in the same circuit. Our data indicate that cortical feedback projections to the MOB crucially regulate food intake via CB1 receptor signaling, linking the feeling of hunger to stronger odor processing. Thus, CB1 receptor-dependent control of cortical feedback projections in olfactory circuits couples internal states to perception and behavior. PMID:24509429

  5. Accessory scrotum in the perineum

    Directory of Open Access Journals (Sweden)

    Pananghat A Kumar

    2011-01-01

    Full Text Available A case of accessory scrotum in a 2-day-old male infant is reported because of its rarity. An overview of sequences during the normal development of male external genitalia has been provided and the deranged mechanism resulting in this anomaly has been reviewed with hypotheses regarding etiology of accessory scrotum.

  6. Accessory scrotum in the perineum

    OpenAIRE

    Pananghat A Kumar; Pavai Arunachalam; Kumar, Prasanna N.

    2011-01-01

    A case of accessory scrotum in a 2-day-old male infant is reported because of its rarity. An overview of sequences during the normal development of male external genitalia has been provided and the deranged mechanism resulting in this anomaly has been reviewed with hypotheses regarding etiology of accessory scrotum.

  7. A direct anterior cingulate pathway to the primate primary olfactory cortex may control attention to olfaction

    Science.gov (United States)

    García-Cabezas, Miguel Á.; Barbas, Helen

    2016-01-01

    Behavioral and functional studies in humans suggest that attention plays a key role in activating the primary olfactory cortex through an unknown circuit mechanism. We report that a novel pathway from the anterior cingulate cortex, an area which has a key role in attention, projects directly to the primary olfactory cortex in rhesus monkeys, innervating mostly the anterior olfactory nucleus. Axons from the anterior cingulate cortex formed synapses mostly with spines of putative excitatory pyramidal neurons and with a small proportion of a neurochemical class of inhibitory neurons that are thought to have disinhibitory effect on excitatory neurons. This novel pathway from the anterior cingulate is poised to exert a powerful excitatory effect on the anterior olfactory nucleus, which is a critical hub for odorant processing via extensive bilateral connections with primary olfactory cortices and the olfactory bulb. Acting on the anterior olfactory nucleus, the anterior cingulate may activate the entire primary olfactory cortex to mediate the process of rapid attention to olfactory stimuli. PMID:23797208

  8. 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.

  9. Accessory Proteins at ERES

    DEFF Research Database (Denmark)

    Klinkenberg, Rafael David

    proteins. Together these components co‐operate in cargo‐selection as well as forming, loading and releasing budding vesicles from specific regions on the membrane surface of the ER. Coat components furthermore convey vesicle targeting towards the Golgi. However, not much is known about the mechanisms...... that regulate the COPII assembly at the vesicle bud site. This thesis provides the first regulatory mechanism of COPII assembly in relation to ER‐membrane lipid‐signal recognition by the accessory protein p125A (Sec23IP). The aim of the project was to characterize p125A function by dissecting two main domains...... in the protein; a putative lipid‐associating domain termed the DDHD domain that is defined by the four amino acid motif that gives the domain its name; and a ubiquitously found domain termed Sterile α‐motif (SAM), which is mostly associated with oligomerization and polymerization. We first show, that the DDHD...

  10. Neural crest and placode contributions to olfactory development.

    Science.gov (United States)

    Suzuki, Jun; Osumi, Noriko

    2015-01-01

    Olfaction is the sense of smell that influences many primitive behaviors for survival, e.g., feeding, reproduction, social interaction, and fear response. The olfactory system is an evolutionarily ancient sensory system and composed of the olfactory epithelium (OE), the olfactory bulb (OB), and the olfactory cortex. The OE gives rise to olfactory receptor neurons (ORNs), i.e., primary sensory receptor cells whose axons project directly to the OB. The ORNs are unique in the way that they are continuously replaced during physiological turnover or following injury throughout life. In the OE, horizontal basal cells, i.e., flat and quiescent cells attached to the basal lamina, are now thought to be tissue stem cells. Although OE cells, especially ORNs, were hypothesized to be derived from the olfactory placode (OP), recent genetic fate-mapping studies using Cre reporter mice indicate a dual origin, i.e., the OP and neural crest (NC), of the olfactory system. The NC is a transient embryonic tissue that is formed between the dorsal neuroepithelium and epidermis. Neural crest cells (NCCs) are multipotent cells that migrate into various target tissues and differentiate into various cell types, including neurons and glia of the peripheral nervous system, cranial cartilage and bone, and melanocytes. Recent studies have revealed that neural crest-derived cells (NCDCs) are widely distributed in adult tissues, and that a subset of NCDCs still possesses NCC-like multipotency. Here, we review classical and recent studies of the olfactory system, especially focusing on the contribution of the NC and OP to the OE development. PMID:25662265

  11. No-Light Light Bulbs

    Science.gov (United States)

    Modern Schools, 1976

    1976-01-01

    A thumbnail sketch of some of the light bulbs manufactured for a purpose other than seeing. These "dark" lamps perform varied tasks including keeping food fresh, detecting and preventing disease, spurring plant growth, heating, and copying printed material. (Author/MLF)

  12. Deep sequencing of the murine olfactory receptor neuron transcriptome.

    Directory of Open Access Journals (Sweden)

    Ninthujah Kanageswaran

    Full Text Available The ability of animals to sense and differentiate among thousands of odorants relies on a large set of olfactory receptors (OR and a multitude of accessory proteins within the olfactory epithelium (OE. ORs and related signaling mechanisms have been the subject of intensive studies over the past years, but our knowledge regarding olfactory processing remains limited. The recent development of next generation sequencing (NGS techniques encouraged us to assess the transcriptome of the murine OE. We analyzed RNA from OEs of female and male adult mice and from fluorescence-activated cell sorting (FACS-sorted olfactory receptor neurons (ORNs obtained from transgenic OMP-GFP mice. The Illumina RNA-Seq protocol was utilized to generate up to 86 million reads per transcriptome. In OE samples, nearly all OR and trace amine-associated receptor (TAAR genes involved in the perception of volatile amines were detectably expressed. Other genes known to participate in olfactory signaling pathways were among the 200 genes with the highest expression levels in the OE. To identify OE-specific genes, we compared olfactory neuron expression profiles with RNA-Seq transcriptome data from different murine tissues. By analyzing different transcript classes, we detected the expression of non-olfactory GPCRs in ORNs and established an expression ranking for GPCRs detected in the OE. We also identified other previously undescribed membrane proteins as potential new players in olfaction. The quantitative and comprehensive transcriptome data provide a virtually complete catalogue of genes expressed in the OE and present a useful tool to uncover candidate genes involved in, for example, olfactory signaling, OR trafficking and recycling, and proliferation.

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

    Science.gov (United States)

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

    2016-06-01

    In this study, the olfactory system of a semi-aquatic turtle, the snapping turtle, has been morphologically investigated by electron microscopy, immunohistochemistry, and lectin histochemistry. The nasal cavity of snapping turtle was divided into the upper and lower chambers, lined by the sensory epithelium containing ciliated and non-ciliated olfactory receptor neurons, respectively. Each neuron expressed both Gαolf, the α-subunit of G-proteins coupling to the odorant receptors, and Gαo, the α-subunit of G-proteins coupling to the type 2 vomeronasal receptors. The axons originating from the upper chamber epithelium projected to the ventral part of the olfactory bulb, while those from the lower chamber epithelium to the dorsal part of the olfactory bulb. Despite the identical expression of G-protein α-subunits in the olfactory receptor neurons, these two projections were clearly distinguished from each other by the differential expression of glycoconjugates. In conclusion, these data indicate the presence of two types of olfactory systems in the snapping turtle. Topographic arrangement of the upper and lower chambers and lack of the associated glands in the lower chamber epithelium suggest their possible involvement in the detection of odorants: upper chamber epithelium in the air and the lower chamber epithelium in the water. PMID:27059760

  14. 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

  15. Histological Structure of the Vomeronasal Organs and Accessory Olfactory Bulbs of Male Mandarin Voles (Microtus mandarinus) at Different Postnatal Ages%棕色田鼠雄性幼体不同发育期犁鼻器和副嗅球的组织结构

    Institute of Scientific and Technical Information of China (English)

    丁小丽; 邰发道

    2005-01-01

    通过对出生后不同发育时期雄性棕色田鼠犁鼻器和副嗅球进行组织学观察,探讨棕色田鼠出生后犁鼻器和副嗅球的发育规律.实验以出生后当天(0日龄),5日龄,15日龄,25日龄以及成年棕色田鼠为研究对象,副嗅球采用Pischinger氏染色法染色,犁鼻器用H.E.染色法染色后进行组织学观察.结果显示,棕色田鼠出生时,犁鼻器和副嗅球就已具有成体的基本结构,随着动物个体的发育,犁鼻上皮逐渐增厚,犁鼻管变长,犁鼻上皮中神经元密度增加;腺体逐渐增大,犁鼻管腔填充物增多,犁鼻管背外侧的静脉血管逐日增大,管腔周围出现越来越多的血管;副嗅球长宽都增加,僧帽细胞层和颗粒细胞层逐渐增长,各层细胞密度变化稍有不同;出生后15日内,僧帽细胞层细胞密度增加,15日龄以后又开始降低,25日龄及成体的僧帽细胞层细胞密度与5日龄的相似;颗粒细胞层细胞密度持续增高.实验结果提示,棕色田鼠5日龄时,犁鼻器和副嗅球已具有了完整的结构,到25日龄时可能达到了功能上的成熟.

  16. Histological structure of the vomeronasal organ and accessory olfactory bulb of the mandarin vole (Microtus mandarinus) and reed vole (M. fostis)%棕色田鼠与沼泽田鼠犁鼻器和副嗅球的组织结构

    Institute of Scientific and Technical Information of China (English)

    邰发道; 王廷正; 张育辉; 郝琳; 孙儒泳

    2003-01-01

    用组织学方法研究了棕色田鼠(Microtus mandarinus)、沼泽田鼠(M. Fostis)副嗅球和犁鼻器的结构及其在两种鼠间的差异,以此探讨两种田鼠的进化机制与适应功能.两种田鼠的犁鼻器位于鼻腔前端鼻中隔基部的两侧,呈管状结构;沿着犁鼻器的长轴犁鼻管呈现不同的形态学特征,犁鼻管直接开口于鼻腔,从前向后沿着长轴旋转,中间管壁(犁鼻粘膜)变成底部,侧面管壁(假覆层上皮)变成犁鼻管顶壁,最终犁鼻管变小成为一个腺体的分支,不同部位具有不同的组织学特征.通过选取中间相似部位对两种田鼠进行比较研究,发现棕色田鼠犁鼻粘膜比沼泽田鼠厚,而其长度却短于沼泽田鼠.棕色田鼠副嗅球颗粒细胞带宽和僧帽细胞带宽均大于沼泽田鼠,而带长却小于沼泽田鼠.相关分析发现,犁鼻器和副嗅球形态有一定的对应关系,这可能和两个结构之间存在着神经投射有关.棕色田鼠幼体的犁鼻粘膜、神经细胞核、假覆层上皮、血管面积均小于成体

  17. Bulbocortical interplay in olfactory information processing via synchronous oscillations.

    Science.gov (United States)

    Fukai, T

    1996-04-01

    Emergence of synchronous oscillatory activity is an inherent feature of the olfactory systems of insects, mollusks and mammals. A class of simple computational models of the mammalian olfactory system consisting of olfactory bulb and olfactory cortex is constructed to explore possible roles of the related neural circuitry in olfactory information processing via synchronous oscillations. In the models, the bulbar neural circuitry is represented by a chain of oscillators and that of cortex is analogous to an associative memory network with horizontal synaptic connections. The models incorporate the backprojection from cortical units to the bulbar oscillators in particular ways. They exhibit rapid and robust synchronous oscillations in the presence of odorant stimuli, while they show either nonoscillatory states or propagating waves in the absence of stimuli, depending on the values of model parameters. In both models, the backprojection is shown to enhance the establishment of large-scale synchrony. The results suggest that the modulation of neural activity through centrifugal inputs may play an important role at the early stage of cortical information processing.

  18. 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.

  19. Ultrasonographic findings of accessory breast

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Ki Keun; Cho, Jae Hyun; Yoon, Choon Sik; Kim, Mi Hye [Yonsei University College of Medicine, Seoul (Korea, Republic of)

    1993-07-15

    Accessory breast is an ectopic breast tissue from developmental remnants. It sometimes begins to make symptom, pain and swelling, during premenstrual period or pregnancy. For it has been known as a rear condition, it has occasionally misdiagnosed as a abnormal mass, such as lymphadenitis or hidradentis. We have analyzed 52 accessory breast tissues prospectively, to document the characteristic findings of accessory breast. In summary, the characteristic sonographic findings of accessory breast were the presence of breast tissue superficial to the axillary fascia or underlying fascia if not in axilla, resembling the patient's own breast pattern, the presence of converging appearance of dilated ducts, presence of nipple and/or areola, the obliteration of inner wall of dermis, the obliteration of subcutaneous fat layer, and the downward displacement of axillary fascia or underlying fascia if not in axilla without interruption.

  20. Roles of the main olfactory and vomeronasal systems in the detection of androstenone in inbred strains of mice

    OpenAIRE

    Vera V. VOZNESSENSKAYA, Maria A.KLYUCHNIKOVA, Charles J. WYSOCKI

    2010-01-01

    We investigated the role of the main olfactory and accessory olfactory systems (MOS and AOS respectively) in the detection of androstenone. We used the following experimental approaches: behavioral, surgical removal of the vomeronasal organ (VNX) followed by histochemical verification and Fos immunohistochemistry. Using a Y-maze paradigm we estimated sensitivity of NZB/B1NJ and CBA/J mice to androstenone. CBA mice were 2,000-fold more sensitive to androstenone than NZB mice. VNX caused a 4- t...

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

    Directory of Open Access Journals (Sweden)

    Laís Soares Rodrigues

    2014-12-01

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

  4. A Method to Measure Humidity Based on Dry-Bulb and Wet-Bulb Temperatures

    OpenAIRE

    Yongping Huang; Ke Zhang; Shufan Yang; Yushan Jin

    2013-01-01

    This study tries to analyze the theory of measuring humidity based on dry-bulb and wet-bulb temperatures. And a theoretical formula is deduced for the calculation of relative humidity from dry-bulb and wet-bulb temperatures. Through analysis of the theoretical formula, a two-dimensional conversion table is produced to transform dry-bulb and wet-bulb temperatures into relative humidity. A method is proposed to obtain humidity by combining searching table and linear smoothing algorithm, which i...

  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. Evidence for a Notch1-mediated transition during olfactory ensheathing cell development.

    Science.gov (United States)

    Miller, Sophie R; Perera, Surangi N; Benito, Cristina; Stott, Simon R W; Baker, Clare V H

    2016-09-01

    Olfactory ensheathing cells (OECs) are a unique glial population found in both the peripheral and central nervous system: they ensheath bundles of unmyelinated olfactory axons from their peripheral origin in the olfactory epithelium to their central synaptic targets in the glomerular layer of the olfactory bulb. Like all other peripheral glia (Schwann cells, satellite glia, enteric glia), OECs are derived from the embryonic neural crest. However, in contrast to Schwann cells, whose development has been extensively characterised, relatively little is known about their normal development in vivo. In the Schwann cell lineage, the transition from multipotent Schwann cell precursor to immature Schwann cell is promoted by canonical Notch signalling. Here, in situ hybridisation and immunohistochemistry data from chicken, mouse and human embryos are presented that suggest a canonical Notch-mediated transition also occurs during OEC development. PMID:27271278

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. 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!

  12. 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.

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

    International Nuclear Information System (INIS)

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

  14. Automobile accessories: Assessment and improvement

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, M. [Univ. of Nevada, Las Vegas, NV (United States)

    1995-11-01

    With mandates and regulatory policies to meet both the California Air Resources Board (CARB) and the Partnership for a New Generation of Vehicles (PNGV), designing vehicles of the future will become a difficult task. As we look into the use of electric and hybrid vehicles, reduction of the required power demand by influential automobile components is necessary in order to obtain performance and range goals. Among those automobile components are accessories. Accessories have a profound impact on the range and mileage of future vehicles with limited amounts of energy or without power generating capabilities such as conventional vehicles. Careful assessment of major power consuming accessories helps us focus on those that need improvement and contributes to attainment of mileage and range goals for electric and hybrid vehicles.

  15. 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.

  16. 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

  17. 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.

  18. Selective gene expression by postnatal electroporation during olfactory interneuron neurogenesis.

    Directory of Open Access Journals (Sweden)

    Alexander T Chesler

    Full Text Available Neurogenesis persists in the olfactory system throughout life. The mechanisms of how new neurons are generated, how they integrate into circuits, and their role in coding remain mysteries. Here we report a technique that will greatly facilitate research into these questions. We found that electroporation can be used to robustly and selectively label progenitors in the Subventicular Zone. The approach was performed postnatally, without surgery, and with near 100% success rates. Labeling was found in all classes of interneurons in the olfactory bulb, persisted to adulthood and had no adverse effects. The broad utility of electroporation was demonstrated by encoding a calcium sensor and markers of intracellular organelles. The approach was found to be effective in wildtype and transgenic mice as well as rats. Given its versatility, robustness, and both time and cost effectiveness, this method offers a powerful new way to use genetic manipulation to understand adult neurogenesis.

  19. Pentobarbitone modulation of NMDA receptors in neurones isolated from the rat olfactory brain.

    OpenAIRE

    Charlesworth, P; Jacobson, I; Richards, C. D.

    1995-01-01

    1. The action of pentobarbitone on the N-methyl-D-aspartate (NMDA) receptors of neurones freshly dissociated from the olfactory bulb and olfactory tubercle has been studied using patch-clamp techniques. 2. Pentobarbitone produced a concentration-dependent depression of the currents evoked by NMDA with an IC50 value of c. 250 microM. 3. Analysis of the NMDA-evoked noise produced power spectra that could be fitted by the sum of two Lorentzians with corner frequencies of 17 and 82 Hz. Pentobarbi...

  20. The therapeutic potential of human olfactory-derived stem cells.

    Science.gov (United States)

    Marshall, C T; Lu, C; Winstead, W; Zhang, X; Xiao, M; Harding, G; Klueber, K M; Roisen, F J

    2006-06-01

    Stem cells from fetal and adult central nervous system have been isolated and characterized, providing populations for potential replacement therapy for traumatic injury repair and neurodegenerative diseases. The regenerative capacity of the olfactory system has attracted scientific interest. Studies focusing on animal and human olfactory bulb ensheathing cells (OECs) have heightened the expectations that OECs can enhance axonal regeneration and repair demyelinating diseases. Harvest of OECs from the olfactory bulb requires highly invasive surgery, which is a major obstacle. In contrast, olfactory epithelium (OE) has a unique regenerative capacity and is readily accessible from its location in the nasal cavity, allowing for harvest without lasting damage to the donor. Adult OE contains progenitors responsible for the normal life-long continuous replacement of neurons and supporting cells. Culture techniques have been established for human OE that generate populations of mitotically active neural progenitors that form neurospheres (Roisen et al., 2001; Winstead et al., 2005). The potential application of this technology includes autologous transplantation where minimal donor material can be isolated, expanded ex vivo, and lineage restricted to a desired phenotype prior to/or after re-implantation. Furthermore, these strategies circumvent the ethical issues that arise with embryonic or fetal tissues. The long term goal is to develop procedures through which a victim of a spinal cord injury or neurodegenerative condition would serve as a source of progenitors for his/her own regenerative grafts, avoiding the need for immunosuppression and ethical controversy. In addition, these cells can provide populations for pharmacological and/or diagnostic evaluation.

  1. Penguins reduced olfactory receptor genes common to other waterbirds

    Science.gov (United States)

    Lu, Qin; Wang, Kai; Lei, Fumin; Yu, Dan; Zhao, Huabin

    2016-01-01

    The sense of smell, or olfaction, is fundamental in the life of animals. However, penguins (Aves: Sphenisciformes) possess relatively small olfactory bulbs compared with most other waterbirds such as Procellariiformes and Gaviiformes. To test whether penguins have a reduced reliance on olfaction, we analyzed the draft genome sequences of the two penguins, which diverged at the origin of the order Sphenisciformes; we also examined six closely related species with available genomes, and identified 29 one-to-one orthologous olfactory receptor genes (i.e. ORs) that are putatively functionally conserved and important across the eight birds. To survey the 29 one-to-one orthologous ORs in penguins and their relatives, we newly generated 34 sequences that are missing from the draft genomes. Through the analysis of totaling 378 OR sequences, we found that, of these functionally important ORs common to other waterbirds, penguins have a significantly greater percentage of OR pseudogenes than other waterbirds, suggesting a reduction of olfactory capability. The penguin-specific reduction of olfactory capability arose in the common ancestor of penguins between 23 and 60 Ma, which may have resulted from the aquatic specializations for underwater vision. Our study provides genetic evidence for a possible reduction of reliance on olfaction in penguins. PMID:27527385

  2. Penguins reduced olfactory receptor genes common to other waterbirds.

    Science.gov (United States)

    Lu, Qin; Wang, Kai; Lei, Fumin; Yu, Dan; Zhao, Huabin

    2016-08-16

    The sense of smell, or olfaction, is fundamental in the life of animals. However, penguins (Aves: Sphenisciformes) possess relatively small olfactory bulbs compared with most other waterbirds such as Procellariiformes and Gaviiformes. To test whether penguins have a reduced reliance on olfaction, we analyzed the draft genome sequences of the two penguins, which diverged at the origin of the order Sphenisciformes; we also examined six closely related species with available genomes, and identified 29 one-to-one orthologous olfactory receptor genes (i.e. ORs) that are putatively functionally conserved and important across the eight birds. To survey the 29 one-to-one orthologous ORs in penguins and their relatives, we newly generated 34 sequences that are missing from the draft genomes. Through the analysis of totaling 378 OR sequences, we found that, of these functionally important ORs common to other waterbirds, penguins have a significantly greater percentage of OR pseudogenes than other waterbirds, suggesting a reduction of olfactory capability. The penguin-specific reduction of olfactory capability arose in the common ancestor of penguins between 23 and 60 Ma, which may have resulted from the aquatic specializations for underwater vision. Our study provides genetic evidence for a possible reduction of reliance on olfaction in penguins.

  3. Penguins reduced olfactory receptor genes common to other waterbirds.

    Science.gov (United States)

    Lu, Qin; Wang, Kai; Lei, Fumin; Yu, Dan; Zhao, Huabin

    2016-01-01

    The sense of smell, or olfaction, is fundamental in the life of animals. However, penguins (Aves: Sphenisciformes) possess relatively small olfactory bulbs compared with most other waterbirds such as Procellariiformes and Gaviiformes. To test whether penguins have a reduced reliance on olfaction, we analyzed the draft genome sequences of the two penguins, which diverged at the origin of the order Sphenisciformes; we also examined six closely related species with available genomes, and identified 29 one-to-one orthologous olfactory receptor genes (i.e. ORs) that are putatively functionally conserved and important across the eight birds. To survey the 29 one-to-one orthologous ORs in penguins and their relatives, we newly generated 34 sequences that are missing from the draft genomes. Through the analysis of totaling 378 OR sequences, we found that, of these functionally important ORs common to other waterbirds, penguins have a significantly greater percentage of OR pseudogenes than other waterbirds, suggesting a reduction of olfactory capability. The penguin-specific reduction of olfactory capability arose in the common ancestor of penguins between 23 and 60 Ma, which may have resulted from the aquatic specializations for underwater vision. Our study provides genetic evidence for a possible reduction of reliance on olfaction in penguins. PMID:27527385

  4. Optophysiological analysis of associational circuits in the olfactory cortex

    Directory of Open Access Journals (Sweden)

    Akari eHagiwara

    2012-04-01

    Full Text Available Primary olfactory cortical areas receive direct input from the olfactory bulb, but also have extensive associational connections that have been mainly studied with classical anatomical methods. Here, we shed light on the functional properties of associational connections in the anterior and posterior piriform cortex (aPC and pPC using optophysiological methods. We found that the aPC receives dense functional connections from the anterior olfactory nucleus (AON, a major hub in olfactory cortical circuits. The local recurrent connectivity within the aPC, long invoked in cortical autoassociative models, is sparse and weak. By contrast, the pPC receives negligible input from the AON, but has dense connections from the aPC as well as more local recurrent connections than the aPC. Finally, there are negligible functional connections from the pPC to aPC. Our study provides a circuit basis for a more sensory role for the aPC in odor processing and an associative role for the pPC.

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

    Directory of Open Access Journals (Sweden)

    Haichen eNiu

    2015-03-01

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

  6. 21 CFR 878.4950 - Manual operating table and accessories and manual operating chair and accessories.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Manual operating table and accessories and manual... Surgical Devices § 878.4950 Manual operating table and accessories and manual operating chair and accessories. (a) Identification. A manual operating table and accessories and a manual operating chair...

  7. 21 CFR 890.3910 - Wheelchair accessory.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Wheelchair accessory. 890.3910 Section 890.3910...) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices § 890.3910 Wheelchair accessory. (a) Identification. A wheelchair accessory is a device intended for medical purposes that is...

  8. Human herpesvirus-6 entry into the central nervous system through the olfactory pathway

    OpenAIRE

    Harberts, Erin; Yao, Karen; Wohler, Jillian E.; Maric, Dragan; Ohayon, Joan; Henkin, Robert; Jacobson, Steven

    2011-01-01

    Viruses have been implicated in the development of neurodegenerative diseases, such as Alzheimer's, Parkinson’s, and multiple sclerosis. Human herpesvirus-6 (HHV-6) is a neurotropic virus that has been associated with a wide variety of neurologic disorders, including encephalitis, mesial temporal lobe epilepsy, and multiple sclerosis. Currently, the route of HHV-6 entry into the CNS is unknown. Using autopsy specimens, we found that the frequency of HHV-6 DNA in the olfactory bulb/tract regio...

  9. Building iPhone OS Accessories

    CERN Document Server

    Maskrey, Ken

    2010-01-01

    This book provides a serious, in-depth look at Apple's External Accessory Framework and the iPhone Accessories API. You'll learn how to create new, integrated solutions that combine iPhone apps with dedicated hardware. The iPhone OS Accessories API expands the opportunities for innovative iPhone developers, allowing you to control and monitor external devices, whether you've built them yourself or obtained them from a third party. What you'll learn * Develop accessories and apps for the iPhone and iPod touch. * Use Apple's External Accessory Framework to create hardware/software interaction. *

  10. Fabricating a hollow bulb obturator

    Directory of Open Access Journals (Sweden)

    Fatih Sari

    2012-01-01

    Full Text Available

    Obturators are generally used in the rehabilitation of the maxillectomy defects. Ideally, obturators should be light, properly fit and construction should be made easily. By decreasing the weight of the prosthesis, the retention and stability may be optimized to allow the obturator for function comfortably during mastication, phonation, and deglutition. In this case, a 65-year-old male patient underwent surgical removal of left part of the maxilla due to the squamous cell carcinoma. In this technique fabrication of a hollow bulb obturator prosthesis as a single unit in heat-cured acrylic resin using a single-step flasking procedure was described. The patient’s functional and esthetic expectations were satisfied.

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

    Science.gov (United States)

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

    2013-02-01

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

  12. Olfactory sensitivity in mammalian species.

    Science.gov (United States)

    Wackermannová, M; Pinc, L; Jebavý, L

    2016-07-18

    Olfaction enables most mammalian species to detect and discriminate vast numbers of chemical structures called odorants and pheromones. The perception of such chemical compounds is mediated via two major olfactory systems, the main olfactory system and the vomeronasal system, as well as minor systems, such as the septal organ and the Grueneberg ganglion. Distinct differences exist not only among species but also among individuals in terms of their olfactory sensitivity; however, little is known about the mechanisms that determine these differences. In research on the olfactory sensitivity of mammals, scientists thus depend in most cases on behavioral testing. In this article, we reviewed scientific studies performed on various mammalian species using different methodologies and target chemical substances. Human and non-human primates as well as rodents and dogs are the most frequently studied species. Olfactory threshold studies on other species do not exist with the exception of domestic pigs. Olfactory testing performed on seals, elephants, and bats focused more on discriminative abilities than on sensitivity. An overview of olfactory sensitivity studies as well as olfactory detection ability in most studied mammalian species is presented here, focusing on comparable olfactory detection thresholds. The basics of olfactory perception and olfactory sensitivity factors are also described. PMID:27070753

  13. A Method to Measure Humidity Based on Dry-Bulb and Wet-Bulb Temperatures

    Directory of Open Access Journals (Sweden)

    Yongping Huang

    2013-09-01

    Full Text Available This study tries to analyze the theory of measuring humidity based on dry-bulb and wet-bulb temperatures. And a theoretical formula is deduced for the calculation of relative humidity from dry-bulb and wet-bulb temperatures. Through analysis of the theoretical formula, a two-dimensional conversion table is produced to transform dry-bulb and wet-bulb temperatures into relative humidity. A method is proposed to obtain humidity by combining searching table and linear smoothing algorithm, which is suitable for rapid control. Error analysis and experimental data indicate that the relative error is less than 4%. The proposed method has certain value for humidity control in industrial control process.

  14. Olfactory Receptor Subgenomes Linked with Broad Ecological Adaptations in Sauropsida.

    Science.gov (United States)

    Khan, Imran; Yang, Zhikai; Maldonado, Emanuel; Li, Cai; Zhang, Guojie; Gilbert, M Thomas P; Jarvis, Erich D; O'Brien, Stephen J; Johnson, Warren E; Antunes, Agostinho

    2015-11-01

    Olfactory receptors (ORs) govern a prime sensory function. Extant birds have distinct olfactory abilities, but the molecular mechanisms underlining diversification and specialization remain mostly unknown. We explored OR diversity in 48 phylogenetic and ecologically diverse birds and 2 reptiles (alligator and green sea turtle). OR subgenomes showed species- and lineage-specific variation related with ecological requirements. Overall 1,953 OR genes were identified in reptiles and 16,503 in birds. The two reptiles had larger OR gene repertoires (989 and 964 genes, respectively) than birds (182-688 genes). Overall, birds had more pseudogenes (7,855) than intact genes (1,944). The alligator had significantly more functional genes than sea turtle, likely because of distinct foraging habits. We found rapid species-specific expansion and positive selection in OR14 (detects hydrophobic compounds) in birds and in OR51 and OR52 (detect hydrophilic compounds) in sea turtle, suggestive of terrestrial and aquatic adaptations, respectively. Ecological partitioning among birds of prey, water birds, land birds, and vocal learners showed that diverse ecological factors determined olfactory ability and influenced corresponding olfactory-receptor subgenome. OR5/8/9 was expanded in predatory birds and alligator, suggesting adaptive specialization for carnivory. OR families 2/13, 51, and 52 were correlated with aquatic adaptations (water birds), OR families 6 and 10 were more pronounced in vocal-learning birds, whereas most specialized land birds had an expanded OR family 14. Olfactory bulb ratio (OBR) and OR gene repertoire were correlated. Birds that forage for prey (carnivores/piscivores) had relatively complex OBR and OR gene repertoires compared with modern birds, including passerines, perhaps due to highly developed cognitive capacities facilitating foraging innovations. PMID:26219582

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2004-12-01

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

  16. An olfactory neuronal network for vapor recognition in an artificial nose.

    Science.gov (United States)

    White, J; Dickinson, T A; Walt, D R; Kauer, J S

    1998-04-01

    Odorant sensitivity and discrimination in the olfactory system appear to involve extensive neural processing of the primary sensory inputs from the olfactory epithelium. To test formally the functional consequences of such processing, we implemented in an artificial chemosensing system a new analytical approach that is based directly on neural circuits of the vertebrate olfactory system. An array of fiber-optic chemosensors, constructed with response properties similar to those of olfactory sensory neurons, provide time-varying inputs to a computer simulation of the olfactory bulb (OB). The OB simulation produces spatiotemporal patterns of neuronal firing that vary with vapor type. These patterns are then recognized by a delay line neural network (DLNN). In the final output of these two processing steps, vapor identity is encoded by the spatial patterning of activity across units in the DLNN, and vapor intensity is encoded by response latency. The OB-DLNN combination thus separates identity and intensity information into two distinct codes carried by the same output units, enabling discrimination among organic vapors over a range of input signal intensities. In addition to providing a well-defined system for investigating olfactory information processing, this biologically based neuronal network performs better than standard feed-forward neural networks in discriminating vapors when small amounts of training data are used.

  17. From Batteries and Bulbs to High Tech.

    Science.gov (United States)

    Schwartz, Maurice L.; Schwartz, Ivan C.

    1986-01-01

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

  18. Light On the Behavior of Light Bulbs.

    Science.gov (United States)

    Armstrong, H. L.

    1985-01-01

    Discusses a problem (on page 523 of "College Physics," by Sears, Zemansky, and Young, published by Addison-Wesley, 1980) concerning light bulbs and resistance. Shows why the assumption of constant resistance is unrealistic and provides guidelines for revision. (DH)

  19. Animal experiments and clinical application of olfactory ensheathing cell transplantation for treatment of spinal cord injury

    Institute of Scientific and Technical Information of China (English)

    Nan Liu; Wei Liu; Baiyu Zhou; Jing Wang; Bing Li

    2008-01-01

    BACKGROUND: The olfactory epithelium can still generate new neurons after arresting its growth and development in the human body. Axons can still be generated and pass through peripheral tissue to reach the olfactory bulb. Thus, olfactory cells have been widely used in the repair of spinal cord injury.OBJECTIVE: Using animal experiments in conjunction with a clinical study of olfactory ensheathing cells, this paper was designed to clarify the function and application prospects of olfactory ensheathing cells, as well as the existing problems with their application. RETRIEVAL STRATEGY: Using the terms "olfactory ensheathing cells, spinal cord injury", we retrieved manuscripts published from January 1990 to June 2007. The languages were limited to English and Chinese. Inclusion criteria: studies addressing the characteristics, basic study, clinical application and prospects of olfactory ensheathing cells; studies that were recently published or were published in high-impact journals. Exclusion criteria: repetitive studies.LITERATURE EVALUATION: The included 29 manuscripts were primarily clinical or basic experimental studies. DATA SYNTHESIS: Following spinal cord injury, spinal neurons die, neurotrophic factors are lacking, and the existing glial scar and cavities hinder axonal growth. One method to repair spinal cord injury is to interfere with the above-mentioned factors based on animal experiments. Myelination and axonal regeneration are the keys to spinal cord injury therapy. Olfactory ensheathing cells can secrete several neurotrophic factors, inhibit horizontal cell reactions, have noticeable neuroprotective effects, and possess a very strong reproductive activity, so they have many advantages in the fields of cell transplantation and gene therapy. However, there still exist many questions and uncertainties, such as the best time window and dose, as well as complications of olfactory ensheathing cell transplantation; precise mechanism of action after olfactory

  20. Mechanical accessories for mobile teleoperators

    International Nuclear Information System (INIS)

    The choice of optimum mechanical accessories for mobile teleoperators involves matching the criteria for emergency response with the available technology. This paper presents a general background to teleoperations, a potpourri of the manipulator systems available, and an argument for force reflecting manipulation. The theme presented is that the accomplishment of humanlike endeavors in hostile environments will be most successful when man model capabilities are utilized. The application of recent electronic technology to manipulator development has made new tools available to be applied to emergency response activities. The development activities described are products of the Consolidated Fuel Reprocessing Program at the Oak Ridge National Laboratory. 13 refs., 7 figs

  1. Advanced Accessory Power Supply Topologies

    Energy Technology Data Exchange (ETDEWEB)

    Marlino, L.D.

    2010-06-15

    This Cooperative Research and Development Agreement (CRADA) began December 8, 2000 and ended September 30, 2009. The total funding provided by the Participant (General Motors Advanced Technology Vehicles [GM]) during the course of the CRADA totaled $1.2M enabling the Contractor (UT-Battelle, LLC [Oak Ridge National Laboratory, a.k.a. ORNL]) to contribute significantly to the joint project. The initial task was to work with GM on the feasibility of developing their conceptual approach of modifying major components of the existing traction inverter/drive to develop low cost, robust, accessory power. Two alternate methods for implementation were suggested by ORNL and both were proven successful through simulations and then extensive testing of prototypes designed and fabricated during the project. This validated the GM overall concept. Moreover, three joint U.S. patents were issued and subsequently licensed by GM. After successfully fulfilling the initial objective, the direction and duration of the CRADA was modified and GM provided funding for two additional tasks. The first new task was to provide the basic development for implementing a cascaded inverter technology into hybrid vehicles (including plug-in hybrid, fuel cell, and electric). The second new task was to continue the basic development for implementing inverter and converter topologies and new technology assessments for hybrid vehicle applications. Additionally, this task was to address the use of high temperature components in drive systems. Under this CRADA, ORNL conducted further research based on GM’s idea of using the motor magnetic core and windings to produce bidirectional accessory power supply that is nongalvanically coupled to the terminals of the high voltage dc-link battery of hybrid vehicles. In order not to interfere with the motor’s torque, ORNL suggested to use the zero-sequence, highfrequency harmonics carried by the main fundamental motor current for producing the accessory power

  2. Sadness might isolate you in a non-smelling world: Olfactory perception and depression

    Directory of Open Access Journals (Sweden)

    Sylvia eSchablitzky

    2014-02-01

    Full Text Available Major depressive disorder (MDD occurs with a high prevalence among the mental illnesses. MDD patients experience sadness and hopelessness, with blunted affective reactivity. However, such depressive episodes are also key symptoms in other depressive disorders, like Bipolar Disorder (BPD or Seasonal Affective Disorder (SAD. Moreover, depressive symptoms can also be found in healthy individuals, but are experienced as less severe or for a shorter duration than in patients. Here, it is aimed to summarize studies investigating odor perception in depression, including depressive states in healthy individuals and patient populations. Odor perception in depression has been assessed with psychophysical methods (olfactory sensitivity, odor identification and discrimination, and odor ratings (intensity, emotional valence, familiarity. In addition, some studies investigated affective reactions to odors, and physiological and anatomical correlates of odor perception in depression. The summary reveals that MDD is associated with a reduced olfactory sensitivity. However, odor identification and discrimination scores seem to be unaffected by depression. The reduced olfactory sensitivity might be associated with a reduced ability to encode olfactory information and a reduced volume of the olfactory bulb. While similar processes seem to occur in healthy individuals experiencing depressive states, they cannot be observed in BPD or SAD patients. However, in order to conclude that the reduced olfactory sensitivity is directly linked to depression, it is suggested that studies should implement control measures of cognitive performances or perceptual abilities in other stimulus modalities. It is concluded that the reduced olfactory performance in MDD patients seems to be disorder-, modality-, and test-specific, and that the application of an appropriate olfactory and cognitive test-battery might be highly useful in the differential diagnosis of MDD.

  3. Axonal transport of cadmium in the olfactory nerve of the pike

    International Nuclear Information System (INIS)

    109Cd2+ was applied in the olfactory chambers of pikes (Esox lucius) and the dynamics of the axoplasmic flow of the metal was determined in the olfactory nerves by gamma spectrometry and autoradiography. The results showed that the 109Cd2+ is transported at a constant rate along the olfactory nerves. The profile of the 109Cd2+ in the nerves showed a wave front of transported metal followed by a saddle region. When the nasal chambers were washed 2 hr after application of the 109Cd2+ well-defined transport peaks for the metal were seen in the olfactory axons. The maximal velocity for the transport of 109Cd2+, which corresponds to the movement of the wave front, was 2.38±0.10 mm/hr (mean±S.E.) at the experimental temperature (10 deg. C). The average velocity for the transport of the 109Cd2+, which corresponds to the peak apex movement of the wave, was 2.18±0.05 mm/hr (mean ±S.E.) at 10 deg. C. The tranported 109Cd2+ was strongly accumulated in the anterior parts of the olfactory bulbs, whereas in other brain areas the levels of the metal remained low. Autoradiography of a pike exposed to 109Cd2+ via the water showed a strong labelling in the receptor-cell-containing olfactory rosettes, whereas other structures in the olfactory chambers were only weakly labelled. The accumulation and axonal transport in the olfactory neurons may be noxious and constitute an important component in the toxicology of cadmium in fish, and this may apply also to some other heavy metals. (author)

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

    Directory of Open Access Journals (Sweden)

    Pascaline eAimé

    2014-09-01

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

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

    Science.gov (United States)

    Aimé, Pascaline; Palouzier-Paulignan, Brigitte; Salem, Rita; Al Koborssy, Dolly; Garcia, Samuel; Duchamp, Claude; Romestaing, Caroline; Julliard, A. Karyn

    2014-01-01

    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 olfactory processing

  6. Recent Trend in Development of Olfactory Displays

    Science.gov (United States)

    Yanagida, Yasuyuki

    An olfactory display is a device that generates scented air with desired concentration of aroma, and delivers it to the user's olfactory organ. In this article, the nature of olfaction is briefly described from the view point of how to configure olfactory displays. Next, component technologies to compose olfactory displays, i.e., making scents and delivering scents, are categorized. Several existing olfactory display systems are introduced to show the current status of research and development of olfactory displays.

  7. The accessory fallopian tube: A rare anomaly

    Directory of Open Access Journals (Sweden)

    Kusum R Gandhi

    2012-01-01

    Full Text Available This paper presents a rare anatomical variation in the form of accessory fallopian tube on right side. The duplication of fallopian tube was observed in a 34-year-old female during routine undergraduate dissection in our department. Fallopian tube is the part of uterus that carries the ovum from the ovary to the uterus. Accessory fallopian tube is the congenital anomaly attached to the ampullary part of main tube. This accessory tube is common site of pyosalpinx, hydrosalpinx, cystic swelling and torsion. The ovum released by the ovary may also be captured by the blind accessory tube leading to infertility or ectopic pregnancy. Hence, all patients of infertility or pelvic inflammatory disease should be screened to rule out the presence of accessory fallopian tube and if encountered should be removed.

  8. The recombination activation gene 1 (Rag1 is expressed in a subset of zebrafish olfactory neurons but is not essential for axon targeting or amino acid detection

    Directory of Open Access Journals (Sweden)

    Friedrich Rainer W

    2005-07-01

    Full Text Available Abstract Background Rag1 (Recombination activation gene-1 mediates genomic rearrangement and is essential for adaptive immunity in vertebrates. This gene is also expressed in the olfactory epithelium, but its function there is unknown. Results Using a transgenic zebrafish line and immunofluorescence, we show that Rag1 is expressed and translated in a subset of olfactory sensory neurons (OSNs. Neurons expressing GFP under the Rag1 promoter project their axons to the lateral region of the olfactory bulb only, and axons with the highest levels of GFP terminate in a single glomerular structure. A subset of GFP-expressing neurons contain Gαo, a marker for microvillous neurons. None of the GFP-positive neurons express Gαolf, Gαq or the olfactory marker protein OMP. Depletion of RAG1, by morpholino-mediated knockdown or mutation, did not affect axon targeting. Calcium imaging indicates that amino acids evoke chemotopically organized glomerular activity patterns in a Rag1 mutant. Conclusion Rag1 expression is restricted to a subpopulation of zebrafish olfactory neurons projecting to the lateral olfactory bulb. RAG1 catalytic activity is not essential for axon targeting, nor is it likely to be required for regulation of odorant receptor expression or the response of OSNs to amino acids.

  9. Are olfactory receptors really olfactive?

    DEFF Research Database (Denmark)

    Giorgi, Franco; Maggio, Roberto; Bruni, Luis Emilio

    2011-01-01

    Any living organism interacts with and responds specifically to environmental molecules by expressing specific olfactory receptors. This specificity will be first examined in causal terms with particular emphasis on the mechanisms controlling olfactory gene expression, cell-to-cell interactions a...

  10. Sprout inhibition in roots, tubers and bulbs

    International Nuclear Information System (INIS)

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

  11. 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.

  12. Ca(2+)-BK channel clusters in olfactory receptor neurons and their role in odour coding.

    Science.gov (United States)

    Bao, Guobin; de Jong, Daniëlle; Alevra, Mihai; Schild, Detlev

    2015-12-01

    Olfactory receptor neurons (ORNs) have high-voltage-gated Ca(2+) channels whose physiological impact has remained enigmatic since the voltage-gated conductances in this cell type were first described in the 1980s. Here we show that in ORN somata of Xenopus laevis tadpoles these channels are clustered and co-expressed with large-conductance potassium (BK) channels. We found approximately five clusters per ORN and twelve Ca(2+) channels per cluster. The action potential-triggered activation of BK channels accelerates the repolarization of action potentials and shortens interspike intervals during odour responses. This increases the sensitivity of individual ORNs to odorants. At the level of mitral cells of the olfactory bulb, odour qualities have been shown to be coded by first-spike-latency patterns. The system of Ca(2+) and BK channels in ORNs appears to be important for correct odour coding because the blockage of BK channels not only affects ORN spiking patterns but also changes the latency pattern representation of odours in the olfactory bulb.

  13. Transplantation of olfactory ensheathing cells for promoting regeneration following spinal cord injury

    Institute of Scientific and Technical Information of China (English)

    Kaijun Liu

    2007-01-01

    OBJECTIVE: To investigate the status of olfactory ensheathing cells (OECs) transplantation in facilitating the regeneration of spinal cord injury.DATA SOURCES: Articles about OECs transplantation in treating spinal cord injury were searched in Pubmed database published in English from January 1981 to December 2005 by using the keywords of "olfactory ensheathing cells, transplantation, spinal cord injury".STUDY SELECTION: The data were checked primarily, literatures related to OECs transplantation and the regeneration of spinal cord injury were selected, whereas the repetitive studies and reviews were excluded.DATA EXTRACTION: Totally 43 articles about OECs transplantation and the regeneration and repair of spinal cord injury were collected, and the repetitive ones were excluded.DATA SYNTHESIS: There were 35 articles accorded with the criteria. OECs are the olfactory ensheathing glias isolated from olfactory bulb and olfactory nerve tissue. OECs have the characters of both Schwann cells in central nervous system and peripheral astrocytes. The transplanted OECs can migrate in the damaged spinal cord of host, can induce and support the regeneration, growth and extension of damaged neuritis.Besides, transgenic technique can enable it to carry some exogenous genes that promote neuronal regeneration, and express some molecules that can facilitate neural regeneration, so as to ameliorate the internal environment of nerve injury, induce the regeneration of damaged spinal cord neurons, which can stimulate the regeneration potential of the damaged spinal cord to reach the purpose of spinal cord regeneration and functional recovery.CONCLUSION: OECs are the glial cells with the energy for growth at mature phase, they can myelinize axons, secrete various biological nutrition factors, and then protect and support neurons, also facilitate neural regeneration. OECs have been successfully isolated from nasal olfactory mucosa and olfactory nerve.Therefore, autologous transplantation

  14. Research Progresses in Fish Olfactory System and Sex Pheromonal Receptors%鱼类嗅觉系统和性信息素受体的研究进展

    Institute of Scientific and Technical Information of China (English)

    赖晓健; 洪万树; 张其永

    2013-01-01

    鱼类嗅觉系统包括外部嗅觉器官、嗅神经和嗅球三个部分.嗅觉器官也称为嗅囊,由嗅上皮和髓质组成.气味物质的化学信息主要由嗅上皮上随机分布的嗅觉感受神经元感知,通过嗅神经将嗅觉信息传递到嗅球,嗅球在空间上有不同的功能分区,嗅觉信息经过嗅球各分区整合后分别传入端脑,发挥其生理功能.性信息素在鱼类生殖过程中的作用是通过嗅觉系统来完成的,其中嗅觉感受神经元上的性信息素受体起着重要作用.鱼类性信息素受体的研究主要从两个方面入手,一是从低浓度特异的性信息素引起嗅觉器官电生理反应或行为反应入手,寻找特异的性信息素受体;二是参照哺乳动物嗅觉受体的研究结果,从嗅觉受体基因遗传保守性入手,研究鱼类性信息素受体的结构与功能.%Fish olfactory system is composed of olfactory sac, olfactory nerve and olfactory bulb. Olfactory sac, also called olfactory organ, is composed of olfactory epithelium and central core. Chemical signals are first detected by the olfactory receptor neurons that randomly distribute in the entire olfactory epithelium, and then transferred to the olfactory bulb through the olfactory nerve. There exist different functional regions in the olfactory bulb, where the chemical signals are integrated and transferred to the telencephalon to play physiological functions. The sex pheromones play their functions through the olfactory system in fish reproduction, and the sex pheromonal receptors of the olfactory neurons play an important role. Usually, two approaches are used to investigate the sex pheromonal receptors in fishes: the first is based on species-specific electrophysiological or behavioral responses to sex pheromones at very low concentrations, and the second is based on the conservative structures of receptors genes taking reference of the mammalian counterparts.

  15. Organic Flower Bulbs From Holland - Outlook for the French Market

    NARCIS (Netherlands)

    Kamphuis, Elise

    2002-01-01

    The Netherlands is a major exporter of flower bulbs in the world. France is amongst the top10 of the biggest importers of Dutch flower bulbs. However, the growing of bulbs is very damaging to the environment. With the use of 1,5 million kilograms of pesticide and 16 million kilograms of artificial f

  16. If the Sun Were a Light Bulb.

    Science.gov (United States)

    Adney, Kenneth J.

    1991-01-01

    An activity in which students compare the sun's brightness with that of a light bulb of known luminosity (in watts) to determine the luminosity of the sun is presented. As an extension, the luminosity value that the student obtains for the sun can also be used to estimate the sun's surface temperature. (KR)

  17. Processing by the main olfactory system of chemosignals that facilitate mammalian reproduction.

    Science.gov (United States)

    Baum, Michael J; Cherry, James A

    2015-02-01

    This article is part of a Special Issue "Chemosignals and Reproduction". Most mammalian species possess two parallel circuits that process olfactory information. One of these circuits, the accessory system, originates with sensory neurons in the vomeronasal organ (VNO). This system has long been known to detect non-volatile pheromonal odorants from conspecifics that influence numerous aspects of social communication, including sexual attraction and mating as well as the release of luteinizing hormone from the pituitary gland. A second circuit, the main olfactory system, originates with sensory neurons in the main olfactory epithelium (MOE). This system detects a wide range of non-pheromonal odors relevant to survival (e.g., food and predator odors). Over the past decade evidence has accrued showing that the main olfactory system also detects a range of volatile odorants that function as pheromones to facilitate mate recognition and activate the hypothalamic-pituitary-gonadal neuroendocrine axis. We review early studies as well as the new literature supporting the view that the main olfactory system processes a variety of different pheromonal cues that facilitate mammalian reproduction. PMID:24929017

  18. Processing by the main olfactory system of chemosignals that facilitate mammalian reproduction.

    Science.gov (United States)

    Baum, Michael J; Cherry, James A

    2015-02-01

    This article is part of a Special Issue "Chemosignals and Reproduction". Most mammalian species possess two parallel circuits that process olfactory information. One of these circuits, the accessory system, originates with sensory neurons in the vomeronasal organ (VNO). This system has long been known to detect non-volatile pheromonal odorants from conspecifics that influence numerous aspects of social communication, including sexual attraction and mating as well as the release of luteinizing hormone from the pituitary gland. A second circuit, the main olfactory system, originates with sensory neurons in the main olfactory epithelium (MOE). This system detects a wide range of non-pheromonal odors relevant to survival (e.g., food and predator odors). Over the past decade evidence has accrued showing that the main olfactory system also detects a range of volatile odorants that function as pheromones to facilitate mate recognition and activate the hypothalamic-pituitary-gonadal neuroendocrine axis. We review early studies as well as the new literature supporting the view that the main olfactory system processes a variety of different pheromonal cues that facilitate mammalian reproduction.

  19. Development of the main olfactory system and main olfactory epithelium-dependent male mating behavior are altered in Go-deficient mice

    Science.gov (United States)

    Choi, Jung-Mi; Kim, Sung-Soo; Choi, Chan-Il; Cha, Hye Lim; Oh, Huy-Hyen; Ghil, Sungho; Lee, Young-Don; Birnbaumer, Lutz; Suh-Kim, Haeyoung

    2016-01-01

    In mammals, initial detection of olfactory stimuli is mediated by sensory neurons in the main olfactory epithelium (MOE) and the vomeronasal organ (VNO). The heterotrimeric GTP-binding protein Go is widely expressed in the MOE and VNO of mice. Early studies indicated that Go expression in VNO sensory neurons is critical for directing social and sexual behaviors in female mice [Oboti L, et al. (2014) BMC Biol 12:31]. However, the physiological functions of Go in the MOE have remained poorly defined. Here, we examined the role of Go in the MOE using mice lacking the α subunit of Go. Development of the olfactory bulb (OB) was perturbed in mutant mice as a result of reduced neurogenesis and increased cell death. The balance between cell types of OB interneurons was altered in mutant mice, with an increase in the number of tyrosine hydroxylase-positive interneurons at the expense of calbindin-positive interneurons. Sexual behavior toward female mice and preference for female urine odors by olfactory sensory neurons in the MOE were abolished in mutant male mice. Our data suggest that Go signaling is essential for the structural and functional integrity of the MOE and for specification of OB interneurons, which in turn are required for the transmission of pheromone signals and the initiation of mating behavior with the opposite sex. PMID:27625425

  20. The olfactory transcriptomes of mice.

    Science.gov (United States)

    Ibarra-Soria, Ximena; Levitin, Maria O; Saraiva, Luis R; Logan, Darren W

    2014-09-01

    The olfactory (OR) and vomeronasal receptor (VR) repertoires are collectively encoded by 1700 genes and pseudogenes in the mouse genome. Most OR and VR genes were identified by comparative genomic techniques and therefore, in many of those cases, only their protein coding sequences are defined. Some also lack experimental support, due in part to the similarity between them and their monogenic, cell-specific expression in olfactory tissues. Here we use deep RNA sequencing, expression microarray and quantitative RT-PCR in both the vomeronasal organ and whole olfactory mucosa to quantify their full transcriptomes in multiple male and female mice. We find evidence of expression for all VR, and almost all OR genes that are annotated as functional in the reference genome, and use the data to generate over 1100 new, multi-exonic, significantly extended receptor gene annotations. We find that OR and VR genes are neither equally nor randomly expressed, but have reproducible distributions of abundance in both tissues. The olfactory transcriptomes are only minimally different between males and females, suggesting altered gene expression at the periphery is unlikely to underpin the striking sexual dimorphism in olfactory-mediated behavior. Finally, we present evidence that hundreds of novel, putatively protein-coding genes are expressed in these highly specialized olfactory tissues, and carry out a proof-of-principle validation. Taken together, these data provide a comprehensive, quantitative catalog of the genes that mediate olfactory perception and pheromone-evoked behavior at the periphery. PMID:25187969

  1. The olfactory transcriptomes of mice.

    Directory of Open Access Journals (Sweden)

    Ximena Ibarra-Soria

    2014-09-01

    Full Text Available The olfactory (OR and vomeronasal receptor (VR repertoires are collectively encoded by 1700 genes and pseudogenes in the mouse genome. Most OR and VR genes were identified by comparative genomic techniques and therefore, in many of those cases, only their protein coding sequences are defined. Some also lack experimental support, due in part to the similarity between them and their monogenic, cell-specific expression in olfactory tissues. Here we use deep RNA sequencing, expression microarray and quantitative RT-PCR in both the vomeronasal organ and whole olfactory mucosa to quantify their full transcriptomes in multiple male and female mice. We find evidence of expression for all VR, and almost all OR genes that are annotated as functional in the reference genome, and use the data to generate over 1100 new, multi-exonic, significantly extended receptor gene annotations. We find that OR and VR genes are neither equally nor randomly expressed, but have reproducible distributions of abundance in both tissues. The olfactory transcriptomes are only minimally different between males and females, suggesting altered gene expression at the periphery is unlikely to underpin the striking sexual dimorphism in olfactory-mediated behavior. Finally, we present evidence that hundreds of novel, putatively protein-coding genes are expressed in these highly specialized olfactory tissues, and carry out a proof-of-principle validation. Taken together, these data provide a comprehensive, quantitative catalog of the genes that mediate olfactory perception and pheromone-evoked behavior at the periphery.

  2. Effect of olive mill wastewater on growth and bulb production of tulip plants infected by bulb diseases

    Energy Technology Data Exchange (ETDEWEB)

    Lykas, C.; Vegalas, I.; Gougaulias, N.

    2014-06-01

    The effect of olive mill wastewater (OMW) on growth of tulip plants infected by common diseases as well as on their new bulbs production is analyzed in this work. Filtered and sterilized OMW was tested as growth inhibitor of Botrytis tulipae, Fusarium oxysporum, Aspergillus niger and Penicillium spp. mycelium. The effect of filtered OMW on uninfected tulip bulbs was also tested as well as on the growth of bulbs infected with the fungus B. tulipae and A. niger in vivo. The mycelium length, severity of scab-like lesions, plant height (PH), fresh mass (FM) and dry mass (DM) of plants and production of new bulbs were recorded. Only the filtered OMW inhibited the in vitro mycelium growth of all tested fungi. However filtered OMW caused infections when it sprayed on uninfected bulbs, malformations on 30% of the plants grown from these bulbs and decrease PH, FM and DM as well as new bulbs production at 75%, 72.4%, 79.1% and 50% respectively. The treatment of B. tulipae infected bulbs with filtered OMW reduced further the PH, FM, DM and the production of new bulbs in 92.1%, 81.4%, 78.7% and 97% respectively. In contrast the treatment of infected bulbs by B. tulipae + A. niger with filtered OMW did not affect PH, FM and the number of new bulbs produced and significantly improved plants DM and the mass of new bulbs. (Author)

  3. Effect of olive mill wastewater on growth and bulb production of tulip plants infected by bulb diseases

    Directory of Open Access Journals (Sweden)

    Christos Lykas

    2014-02-01

    Full Text Available The effect of olive mill wastewater (OMW on growth of tulip plants infected by common diseases as well as on their new bulbs production is analyzed in this work. Filtered and sterilized OMW was tested as growth inhibitor of Botrytis tulipae, Fusarium oxysporum, Aspergillus niger and Penicillium spp. mycelium. The effect of filtered OMW on uninfected tulip bulbs was also tested as well as on the growth of bulbs infected with the fungus B. tulipae and A. niger in vivo. The mycelium length, severity of scab-like lesions, plant height (PH, fresh mass (FM and dry mass (DM of plants and production of new bulbs were recorded. Only the filtered OMW inhibited the in vitro mycelium growth of all tested fungi. However filtered OMW caused infections when it sprayed on uninfected bulbs, malformations on 30% of the plants grown from these bulbs and decrease PH, FM and DM as well as new bulbs production at 75%, 72.4%, 79.1% and 50% respectively. The treatment of B. tulipae infected bulbs with filtered OMW reduced further the PH, FM, DM and the production of new bulbs in 92.1%, 81.4%, 78.7% and 97% respectively. In contrast the treatment of infected bulbs by B. tulipae + A. niger with filtered OMW did not affect PH, FM and the number of new bulbs produced and significantly improved plants DM and the mass of new bulbs.

  4. [The 2004 Nobel Prize for Physiology or Medicine for research into smell receptors and the organization of the olfactory system].

    Science.gov (United States)

    Burbach, J P H

    2004-12-25

    The 2004 Nobel Prize for Physiology or Medicine has been awarded to Richard Axel and Linda B. Buck, for their discovery of smell receptors and the organisation of the olfactory system. Their original discovery concerned the identification of some 1000 genes that code for smell receptors in the olfactory epithelium of the rat. They also demonstrated that each receptor can only be activated by a limited number of odourants and that there is some overlap in specificity with other smell receptors. Odourants in inhaled air are specifically recognized and bound by the smell receptors on the olfactory neurones in the nasal epithelium. The activated neurones send an electrical signal to the mitral cells, the dendrites of which lie in the glomeruli of the olfactory bulb. In each olfactory neuron only one smell receptor gene is expressed. Neurones with the same type of receptor are spread throughout the epithelium but converge in the same glomerulus. An olfactory map is formed by means of mitral-cell projections which run to the cerebral cortex as well as to other parts of the brain. Possibly the information gained about odourants will be applied in the areas of physiology and pathophysiology; in the field of pharmacology for example where odourants may be used in the treatment of disorders of fertility, behaviour or mood.

  5. 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, incubation stage of EP and histopathologic manifestations showed that the group with transplanted OECs regained more improvement in hindlimb than the control group. Conclusion The OECs of two sources have the same ability to regain and improve the axonal function which can promote axons regeneration of SCI.

  6. Melanocortin receptors and their accessory proteins

    OpenAIRE

    Cooray, Sadani N.; Clark, Adrian J.L.

    2010-01-01

    Abstract The melanocortin receptor family consists of 5 members which belong to the GPCR superfamily. Their specific ligands, the melanocortins are peptide hormones which are formed by the proteolytic cleavage of the proopiomelanocortin (POMC) protein. It is now recognised that certain GPCRs require accessory proteins for their function. Like these GPCRs the melanocortin receptor family is also known to be associated with accessory proteins that regulate their function. ...

  7. Olfactory receptor signaling.

    Science.gov (United States)

    Antunes, Gabriela; Simoes de Souza, Fabio Marques

    2016-01-01

    The guanine nucleotide protein (G protein)-coupled receptors (GPCRs) superfamily represents the largest class of membrane protein in the human genome. More than a half of all GPCRs are dedicated to interact with odorants and are termed odorant-receptors (ORs). Linda Buck and Richard Axel, the Nobel Prize laureates in physiology or medicine in 2004, first cloned and characterized the gene family that encode ORs, establishing the foundations to the understanding of the molecular basis for odor recognition. In the last decades, a lot of progress has been done to unravel the functioning of the sense of smell. This chapter gives a general overview of the topic of olfactory receptor signaling and reviews recent advances in this field. PMID:26928542

  8. Connectivity from OR37 expressing olfactory sensory neurons to distinct cell types in the hypothalamus

    Directory of Open Access Journals (Sweden)

    Andrea eBader

    2012-11-01

    Full Text Available Olfactory sensory neurons which express a member from the OR37 subfamily of odorant receptor genes are wired to the main olfactory bulb in a unique monoglomerular fashion; from these glomeruli an untypical connectivity into higher brain centers exists. In the present study we have investigated by DiI and transsynaptic tracing approaches how the connection pattern from these glomeruli into distinct hypothalamic nuclei is organized. The application of DiI onto the ventral domain of the bulb which harbors the OR37 glomeruli resulted in the labeling of fibers within the paraventricular and supraoptic nucleus of the hypothalamus; some of these fibers were covered with varicose-like structures. No DiI-labeled cell somata were detectable in these nuclei. The data indicate that projection neurons which originate in the OR37 region of the main olfactory bulb form direct connections into these nuclei. The cells that were labeled by the transsynaptic tracer WGA in these nuclei were further characterized. Their distribution pattern in the paraventricular nucleus was reminiscent of cells which produce distinct neuropeptides. Double labeling experiments confirmed that they contained vasopressin, but not the related neuropeptide oxytocin. Morphological analysis revealed that they comprise of magno- and parvocellular cells. A comparative investigation of the WGA-positive cells in the supraoptic nucleus demonstrated that these were vasopressin-positive, as well, whereas oxytocin-producing cells of this nucleus also contained no transsynaptic tracer. Together, the data demonstrate a connectivity from OR37 expressing sensory neurons to distinct hypothalamic neurons with the same neuropeptide content.

  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. Orientation in birds. Olfactory navigation.

    Science.gov (United States)

    Papi, F

    1991-01-01

    Research work on the olfactory navigation of birds, which has only recently attracted attention, has shown that many wild species rely on an osmotactic mechanism to find food sources, even at a considerable distance. The homing pigeon, the only bird to have been thoroughly investigated with respect to olfactory navigation, has been found to rely on local odours for homeward orientation, and to integrate olfactory cues perceived during passive transportation with those picked up at the release site. It is possible to design experiments in which birds are given false olfactory information, and predictions about the effects of this can be made and tested. Pigeons are able to home from unfamiliar sites because they acquire an olfactory map extending beyond the area they have flown over. The olfactory map is built up by associating wind-borne odours with the direction from which they come; this was shown by experiments which aimed to prevent, limit or alter this association. One aim of the research work has been to test whether pigeons flying over unfamiliar areas also rely or can learn to rely on non-olfactory cues, depending on their local availability, and/or on the methods of rearing and training applied to them. Various evaluations have been made of the results; the most recent experiments, however, confirm that pigeons do derive directional information from atmospheric odours. A neurobiological approach is also in progress; its results show that some telencephalic areas are involved in orientation and olfactory navigation. The lack of any knowledge about the distribution and chemical nature of the odorants which allow pigeons to navigate hinders progress in this area of research.

  11. Synaptic degeneration and remodelling after fast kindling of the olfactory bulb

    DEFF Research Database (Denmark)

    Woldbye, D P; Bolwig, T G; Kragh, J;

    1996-01-01

    in the basolateral amygdala and dentate gyrus, suggesting that these regions may be functionally altered during the kindling process. In the piriform cortex and dentate gyrus increased NCAM/D3(SNAP-25) ratios found ipsilaterally at seven days after kindling probably reflect an elevated rate of synaptic remodelling....... At this time, however, an overall pattern of ipsilateral decreases in the synaptic marker proteins NCAM and D3(SNAP-25) indicated that this remodelling occurred on a background of synaptic degeneration. These results confirm previous studies showing that kindling is associated with synaptic remodelling...

  12. The h-current in periglomerular dopaminergic neurons of the mouse olfactory bulb.

    Directory of Open Access Journals (Sweden)

    Angela Pignatelli

    Full Text Available The properties of the hyperpolarization-activated cation current (I(h were investigated in rat periglomerular dopaminergic neurons using patch-clamp recordings in thin slices. A reliable identification of single dopaminergic neurons was made possible by use of a transgenic line of mice expressing eGFP under the tyrosine hydroxylase promoter. At 37 °C and minimizing the disturbance of the intracellular milieu with perforated patches, this current shows a midpoint of activation around -82.7 mV, with a significant level of opening already at rest, thereby giving a substantial contribution to the resting potential, and ultimately playing a relevant function in the control of the cell excitability. The blockage of I(h has a profound influence on the spontaneous firing of these neurons, which result as strongly depressed. However the effect is not due to a direct role of the current in the pacemaker process, but to the I(h influence on the resting membrane potential. I(h kinetics is sensitive to the intracellular levels of cAMP, whose increase promotes a shift of the activation curve towards more positive potentials. The direct application of DA and 5-HT neurotransmitters, physiologically released onto bulbar dopaminergic neurons and known to act on metabotropic receptors coupled to the cAMP pathway, do not modifythe I(h amplitude. On the contrary, noradrenaline almost halves the I(h amplitude. Our data indicate that the HCN channels do not participate directly to the pacemaker activity of periglomerular dopaminergic neurons, but influence their resting membrane potential by controlling the excitability profile of these cells, and possibly affecting the processing of sensory information taking place at the entry of the bulbar circuitry.

  13. THE SILICON OLFACTORY BULB: A NEUROMORPHIC APPROACH TO MOLECULAR SENSING WITH CHEMORECEPTIVE NEURON MOS TRANSISTORS (CNMOS)

    Science.gov (United States)

    Within the 3 -year effort, we have established several major findings: Chemical sensor in fluid environment with inorganic and polymer sensing surfaces (1,5): Conventional metal oxide semiconductor field effect transistor (MOSFET)-based chemical sensing su...

  14. 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

  15. 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.

  16. Reading Out Olfactory Receptors: Feedforward Circuits Detect Odors in Mixtures without Demixing.

    Science.gov (United States)

    Mathis, Alexander; Rokni, Dan; Kapoor, Vikrant; Bethge, Matthias; Murthy, Venkatesh N

    2016-09-01

    The olfactory system, like other sensory systems, can detect specific stimuli of interest amidst complex, varying backgrounds. To gain insight into the neural mechanisms underlying this ability, we imaged responses of mouse olfactory bulb glomeruli to mixtures. We used this data to build a model of mixture responses that incorporated nonlinear interactions and trial-to-trial variability and explored potential decoding mechanisms that can mimic mouse performance when given glomerular responses as input. We find that a linear decoder with sparse weights could match mouse performance using just a small subset of the glomeruli (∼15). However, when such a decoder is trained only with single odors, it generalizes poorly to mixture stimuli due to nonlinear mixture responses. We show that mice similarly fail to generalize, suggesting that they learn this segregation task discriminatively by adjusting task-specific decision boundaries without taking advantage of a demixed representation of odors. PMID:27593177

  17. Perception of odors linked to precise timing in the olfactory system.

    Directory of Open Access Journals (Sweden)

    Michelle R Rebello

    2014-12-01

    Full Text Available While the timing of neuronal activity in the olfactory bulb (OB relative to sniffing has been the object of many studies, the behavioral relevance of timing information generated by patterned activation within the bulbar response has not been explored. Here we show, using sniff-triggered, dynamic, 2-D, optogenetic stimulation of mitral/tufted cells, that virtual odors that differ by as little as 13 ms are distinguishable by mice. Further, mice are capable of discriminating a virtual odor movie based on an optically imaged OB odor response versus the same virtual odor devoid of temporal dynamics-independently of the sniff-phase. Together with studies showing the behavioral relevance of graded glomerular responses and the response timing relative to odor sampling, these results imply that the mammalian olfactory system is capable of very high transient information transmission rates.

  18. Discordance between olfactory psychophysical measurements and olfactory event related potentials in five patients with olfactory dysfunction following upper respiratory infection

    Institute of Scientific and Technical Information of China (English)

    GUAN Jing; NI Dao-feng; WANG Jian; GAO Zhi-qiang

    2009-01-01

    Background Subjective olfactory tests are easy to perform and popularly applied in the clinic, but using only these, it is difficult to diagnose all disorders of the olfactory system. The olfactory event related potentials technique offers further insight into the olfactory system and is an ideal objective test. This analysis was of subjective and objective data on the olfactory function of twelve patients with loss of smell associated with an upper respiratory infection (URI). Methods We tested the twelve patients with URI induced olfactory loss by medical history, physical examination of the head and neck, olfactory tests and medical imaging. Olfactory function was assessed by Toyota and Takagi olfactometry including olfactory detection and recognition thresholds and olfactory event-related potentials (OERPs) recorded with OEP-98C Olfactometer. Results An unusual phenomenon was observed in five patients in whom the subjective detection and recognition thresholds were normal, while the expected OERPs were not detectable. Conclusions We suggest that the discordance between olfactory psychophysical measurements and OERPs might be the results of abnormal electrephysiology related with olfactory neuropathy caused by viral URI. In addition, the measurement of OERPs might play a significant role in evaluating olfactory dysfunction.

  19. ACCESSORY SPLEEN: A CLINICALLY RELEVANT ANATOMIC ANOMALY

    Directory of Open Access Journals (Sweden)

    Prachi Saffar

    2016-02-01

    Full Text Available The purpose of our study is to emphasize on the clinical relevance of the presence of accessory spleen. It is not only a well-documented anatomic anomaly, it holds special significance in the differential diagnosis of intra-abdominal tumours and lymphadenopathy. MATERIALS AND METHODS Thirty male cadavers from North Indian population above the age of 60 yrs. were dissected in the Anatomy Department of FMHS, SGT University, Gurgaon, over a period of 5 yrs. (Sep 2010-Aug 2015 and presence of accessory spleen recorded. Tissue from the accessory spleen was also subjected to routine histological processing and slide prepared by haematoxylin and eosin staining. RESULTS Accessory spleen was present in two cadavers near the splenic hilum. One was 3.9 cm in the long axis and weighed about 48.4 grams, while the other was 1.2 cm in long axis and weighed about 12.5 grams. One had a separate arterial branch from the main splenic artery; that it was splenic tissue was confirmed histologically. DISCUSSION The presence of accessory spleen is considered to be due to embryonic non-fusion of the splenic aggregate with the main mass. CONCLUSION Though accessory spleen in itself pose no clinical problems, its significance cannot be undermined. Surgeons and radiologists are advised to look for and rule out the presence of accessory spleen, especially while evaluating a case of abdominal and perineal pathology, else it may be wrongly diagnosed as malignant tumour or enlarged lymph node leading to grave consequences.

  20. [Clinical features of accessory parotid gland tumors].

    Science.gov (United States)

    Iguchi, Hiroyoshi; Wada, Tadashi; Yamamoto, Hidefumi; Yamada, Kei; Matsushita, Naoki; Okamoto, Sachimi; Teranishi, Yuichi; Koda, Yuki; Kosugi, Yuki; Yamane, Hideo

    2013-12-01

    Accessory parotid gland tumors are relatively rare; hence, adequately detailed clinical analyses of these tumors are difficult to perform at a single institution. In this report, we describe the findings for 65 patients [29 men, 36 women; median age, 51 (9-81) years] with accessory parotid gland tumors, consisting of 4 cases documented by us and 61 cases previously reported by other Japanese authors. Approximately 50% of the patients were treated in an otolaryngology department, while the remaining patients were treated in plastic surgery, oral surgery, or dermatology departments. In 4 patients, the results of preoperative fine-needle aspiration cytology indicated that the tumor was benign; however, the postoperative histopathology results revealed malignant tumors. The frequencies of malignant and benign tumors were 44.6% (n = 29) and 55.4% (n = 36), respectively. Mucoepidermoid carcinoma and pleomorphic adenoma were the most frequent types of malignant and benign accessory parotid gland tumors, respectively. Among the various surgical methods that were used, such as direct cheek and intraoral incisions, a standard parotidectomy incision was the most preferred treatment approach for these tumors. Recently, an endoscopic approach has also been found to yield satisfactory results. An optimal approach should be selected after evaluating the advantages and disadvantages of these methods. No definite guidelines are available regarding the choice of elective neck dissection and postoperative radiation therapy for malignant accessory parotid gland tumors. Although tumor resection (plus elective neck dissection) and postoperative radiation therapy have been frequently performed for various kinds of malignant accessory parotid gland tumors to date, additional studies are needed regarding the criteria for selecting elective neck dissection and postoperative radiation therapy. Since the malignancy rate for accessory parotid gland tumors is higher than that for parotid gland

  1. Environmental neurotoxic challenge of conditional alpha-synuclein transgenic mice predicts a dopaminergic olfactory-striatal interplay in early PD.

    Science.gov (United States)

    Nuber, Silke; Tadros, Daniel; Fields, Jerel; Overk, Cassia Rose; Ettle, Benjamin; Kosberg, Kori; Mante, Michael; Rockenstein, Edward; Trejo, Margarita; Masliah, Eliezer

    2014-04-01

    The olfactory bulb (OB) is one of the first brain regions in Parkinson's disease (PD) to contain alpha-synuclein (α-syn) inclusions, possibly associated with nonmotor symptoms. Mechanisms underlying olfactory synucleinopathy, its contribution to progressive aggregation pathology and nigrostriatal dopaminergic loss observed at later stages, remain unclear. A second hit, such as environmental toxins, is suggestive for α-syn aggregation in olfactory neurons, potentially triggering disease progression. To address the possible pathogenic role of olfactory α-syn accumulation in early PD, we exposed mice with site-specific and inducible overexpression of familial PD-linked mutant α-syn in OB neurons to a low dose of the herbicide paraquat. Here, we found that olfactory α-syn per se elicited structural and behavioral abnormalities, characteristic of an early time point in models with widespread α-syn expression, including hyperactivity and increased striatal dopaminergic marker. Suppression of α-syn reversed the dopaminergic phenotype. In contrast, paraquat treatment synergistically induced degeneration of olfactory dopaminergic cells and opposed the higher reactive phenotype. Neither neurodegeneration nor behavioral abnormalities were detected in paraquat-treated mice with suppressed α-syn expression. By increasing calpain activity, paraquat induced a pathological cascade leading to inhibition of autophagy clearance and accumulation of calpain-cleaved truncated and insoluble α-syn, recapitulating biochemical and structural changes in human PD. Thus our results underscore the primary role of proteolytic failure in aggregation pathology. In addition, we provide novel evidence that olfactory dopaminergic neurons display an increased vulnerability toward neurotoxins in dependence to presence of human α-syn, possibly mediating an olfactory-striatal dopaminergic network dysfunction in mouse models and early PD. PMID:24509835

  2. Global expression profiling of globose basal cells and neurogenic progression within the olfactory epithelium.

    Science.gov (United States)

    Krolewski, Richard C; Packard, Adam; Schwob, James E

    2013-03-01

    Ongoing, lifelong neurogenesis maintains the neuronal population of the olfactory epithelium in the face of piecemeal neuronal turnover and restores it following wholesale loss. The molecular phenotypes corresponding to different stages along the progression from multipotent globose basal cell (GBC) progenitor to differentiated olfactory sensory neuron are poorly characterized. We used the transgenic expression of enhanced green fluorescent protein (eGFP) and cell surface markers to FACS-isolate ΔSox2-eGFP(+) GBCs, Neurog1-eGFP(+) GBCs and immature neurons, and ΔOMP-eGFP(+) mature neurons from normal adult mice. In addition, the latter two populations were also collected 3 weeks after olfactory bulb ablation, a lesion that results in persistently elevated neurogenesis. Global profiling of mRNA from the populations indicates that all stages of neurogenesis share a cohort of >2,100 genes that are upregulated compared to sustentacular cells. A further cohort of >1,200 genes are specifically upregulated in GBCs as compared to sustentacular cells and differentiated neurons. The increased rate of neurogenesis caused by olfactory bulbectomy had little effect on the transcriptional profile of the Neurog1-eGFP(+) population. In contrast, the abbreviated lifespan of ΔOMP-eGFP(+) neurons born in the absence of the bulb correlated with substantial differences in gene expression as compared to the mature neurons of the normal epithelium. Detailed examination of the specific genes upregulated in the different progenitor populations revealed that the chromatin modifying complex proteins LSD1 and coREST were expressed sequentially in upstream ΔSox2-eGFP(+) GBCs and Neurog1-eGFP(+) GBCs/immature neurons. The expression patterns of these proteins are dynamically regulated after activation of the epithelium by methyl bromide lesion.

  3. Global expression profiling of globose basal cells and neurogenic progression within the olfactory epithelium.

    Science.gov (United States)

    Krolewski, Richard C; Packard, Adam; Schwob, James E

    2013-03-01

    Ongoing, lifelong neurogenesis maintains the neuronal population of the olfactory epithelium in the face of piecemeal neuronal turnover and restores it following wholesale loss. The molecular phenotypes corresponding to different stages along the progression from multipotent globose basal cell (GBC) progenitor to differentiated olfactory sensory neuron are poorly characterized. We used the transgenic expression of enhanced green fluorescent protein (eGFP) and cell surface markers to FACS-isolate ΔSox2-eGFP(+) GBCs, Neurog1-eGFP(+) GBCs and immature neurons, and ΔOMP-eGFP(+) mature neurons from normal adult mice. In addition, the latter two populations were also collected 3 weeks after olfactory bulb ablation, a lesion that results in persistently elevated neurogenesis. Global profiling of mRNA from the populations indicates that all stages of neurogenesis share a cohort of >2,100 genes that are upregulated compared to sustentacular cells. A further cohort of >1,200 genes are specifically upregulated in GBCs as compared to sustentacular cells and differentiated neurons. The increased rate of neurogenesis caused by olfactory bulbectomy had little effect on the transcriptional profile of the Neurog1-eGFP(+) population. In contrast, the abbreviated lifespan of ΔOMP-eGFP(+) neurons born in the absence of the bulb correlated with substantial differences in gene expression as compared to the mature neurons of the normal epithelium. Detailed examination of the specific genes upregulated in the different progenitor populations revealed that the chromatin modifying complex proteins LSD1 and coREST were expressed sequentially in upstream ΔSox2-eGFP(+) GBCs and Neurog1-eGFP(+) GBCs/immature neurons. The expression patterns of these proteins are dynamically regulated after activation of the epithelium by methyl bromide lesion. PMID:22847514

  4. An olfactory ‘stress test’ may detect preclinical Alzheimer’s disease

    Directory of Open Access Journals (Sweden)

    Schofield Peter W

    2012-05-01

    Full Text Available Abstract Background The olfactory bulb (OB receives extensive cholinergic input from the basal forebrain and is affected very early in Alzheimer’s disease (AD. We speculated that an olfactory ‘stress test’ (OST, targeting the OB, might be used to unmask incipient AD. We investigated if change in olfactory performance following intranasal atropine was associated with several known antecedents or biomarkers of AD. Methods We measured change in performance on the University of Pennsylvania Smell Identification Test (UPSIT in the left nostril before (20-items and after (remaining 20-items intranasal administration of 1 mg of atropine. We administered cognitive tests, measured hippocampal volume from MRI scans and recorded Apolipoprotein E genotype as indices relevant to underlying AD. Results In a convenience sample of 56 elderly individuals (14 probable AD, 13 cognitive impairment no dementia, 29 cognitively intact the change in UPSIT score after atropine (‘atropine effect’ = AE correlated significantly with demographically scaled episodic memory score (r = 0.57, p Conclusions The OST using atropine as an olfactory probe holds promise as a simple, inexpensive screen for early and preclinical AD and further work, including longitudinal studies, is needed to explore this possibility.

  5. Physiological and morphological characterization of honeybee olfactory neurons combining electrophysiology, calcium imaging and confocal microscopy.

    Science.gov (United States)

    Galizia, C G; Kimmerle, B

    2004-01-01

    The insect antennal lobe is the first brain structure to process olfactory information. Like the vertebrate olfactory bulb the antennal lobe is substructured in olfactory glomeruli. In insects, glomeruli can be morphologically identified, and have characteristic olfactory response profiles. Local neurons interconnect glomeruli, and output (projection) neurons project to higher-order brain centres. The relationship between their elaborate morphology and their physiology is not understood. We recorded electrophysiologically from antennal lobe neurons, and iontophoretically injected a calcium-sensitive dye. We then measured their spatio-temporal calcium responses to a variety of odours. Finally, we confocally reconstructed the neurons, and identified the innervated glomeruli. An increase or decrease in spiking frequency corresponded to an intracellular calcium increase or decrease in the cell. While intracellular recordings generally lasted between 10 and 30 min, calcium imaging was stable for up to 2 h, allowing a more detailed physiological analysis. The responses indicate that heterogeneous local neurons get input in the glomerulus in which they branch most strongly. In many cases, the physiological response properties of the cells corresponded to the known response profile of the innervated glomerulus. In other words, the large variety of response profiles generally found when comparing antennal lobe neurons is reduced to a more predictable response profile when the innervated glomerulus is known. PMID:14639486

  6. Innate Predator Odor Aversion Driven by Parallel Olfactory Subsystems that Converge in the Ventromedial Hypothalamus.

    Science.gov (United States)

    Pérez-Gómez, Anabel; Bleymehl, Katherin; Stein, Benjamin; Pyrski, Martina; Birnbaumer, Lutz; Munger, Steven D; Leinders-Zufall, Trese; Zufall, Frank; Chamero, Pablo

    2015-05-18

    The existence of innate predator aversion evoked by predator-derived chemostimuli called kairomones offers a strong selective advantage for potential prey animals. However, it is unclear how chemically diverse kairomones can elicit similar avoidance behaviors. Using a combination of behavioral analyses and single-cell Ca(2+) imaging in wild-type and gene-targeted mice, we show that innate predator-evoked avoidance is driven by parallel, non-redundant processing of volatile and nonvolatile kairomones through the activation of multiple olfactory subsystems including the Grueneberg ganglion, the vomeronasal organ, and chemosensory neurons within the main olfactory epithelium. Perturbation of chemosensory responses in specific subsystems through disruption of genes encoding key sensory transduction proteins (Cnga3, Gnao1) or by surgical axotomy abolished avoidance behaviors and/or cellular Ca(2+) responses to different predator odors. Stimulation of these different subsystems resulted in the activation of widely distributed target regions in the olfactory bulb, as assessed by c-Fos expression. However, in each case, this c-Fos increase was observed within the same subnuclei of the medial amygdala and ventromedial hypothalamus, regions implicated in fear, anxiety, and defensive behaviors. Thus, the mammalian olfactory system has evolved multiple, parallel mechanisms for kairomone detection that converge in the brain to facilitate a common behavioral response. Our findings provide significant insights into the genetic substrates and circuit logic of predator-driven innate aversion and may serve as a valuable model for studying instinctive fear and human emotional and panic disorders. PMID:25936549

  7. The mouse olfactory peduncle. 3. Development of neurons, glia and centrifugal afferents

    Directory of Open Access Journals (Sweden)

    Peter eBrunjes

    2014-06-01

    Full Text Available The present series of studies was designed to provide a general overview of the development of the region connecting the olfactory bulb to the forebrain. The olfactory peduncle contains several structures involved in processing odor information with the anterior olfactory nucleus (cortex being the largest and most studied. Results indicate that considerable growth occurs in the peduncle from postnatal day (P10-P20, with reduced expansion from P20-P30. No evidence was found for the addition of new projection or interneurons during the postnatal period. GABAergic cells decreased in both number and density after P10. Glial populations exhibited different patterns of development, with astrocytes declining in density from P10-P30, and both oligodendrocytes and microglia increasing through the interval. Myelination in the anterior commissure emerged between P11-14. Dense cholinergic innervation was observed at P10 and remained relatively stable through P30, while considerable maturation of serotonergic innervation occurred through the period. Unilateral naris occlusion from P1-P30 resulted in about a 30% reduction in the size of the ipsilateral peduncle but few changes were observed on the contralateral side. The ipsilateral peduncle also exhibited higher densities of GAD67- containing interneurons and cholinergic fibers suggesting a delay in normal developmental pruning. Lower densities of interneurons expressing CCK, somatostatin and NPY and in myelin basic protein staining were also observed. Understanding variations in developmental trajectories within the olfactory peduncle may be an important tool for unravelling the functions of the region.

  8. Impaired structural hippocampal plasticity is associated with emotional and memory deficits in the olfactory bulbectomized rat.

    Science.gov (United States)

    Morales-Medina, J C; Juarez, I; Venancio-García, E; Cabrera, S N; Menard, C; Yu, W; Flores, G; Mechawar, N; Quirion, R

    2013-04-16

    Disturbances in olfactory circuitry have been associated with depression in humans. The olfactory bulbectomized (OBX lesion) has been largely used as a model of depression-like behavior in the rat. However, quantitative neuronal rearrangements in key brain regions in this animal model have not been evaluated yet. Accordingly, we investigated changes in hippocampal plasticity as well as behavioral deficits in this animal model. OBX-induced behavioral deficits were studied in a battery of tests, namely the open field test (OFT), forced swim test (FST), and spatial memory disturbances in the Morris water maze (MWM). To characterize the neuronal remodeling, neuroanatomical rearrangements were investigated in the CA1 hippocampus and piriform cortex (PirC), brain regions receiving inputs from the olfactory bulbs and associated with emotional or olfactory processes. Additionally, cell proliferation and survival of newborn cells in the adult dentate gyrus (DG) of the hippocampus were also determined. OBX induced hyperlocomotion and enhanced rearing and grooming in the OFT, increased immobility in the FST as well as required a longer time to find the hidden platform in the MWM. OBX also induced dendritic atrophy in the hippocampus and PirC. In addition, cell proliferation was decreased while the survival remained unchanged in the DG of these animals. These various features are also observed in depressed subjects, adding further support to the validity and usefulness of this model to evaluate potential novel antidepressants. PMID:23357118

  9. Differential Axonal Projection of Mitral and Tufted Cells in the Mouse Main Olfactory System

    Directory of Open Access Journals (Sweden)

    Shin Nagayama

    2010-09-01

    Full Text Available In the past decade, much has been elucidated regarding the functional organization of the axonal connection of olfactory sensory neurons to olfactory bulb (OB glomeruli. However, the manner in which projection neurons of the OB process odorant input and send this information to higher brain centers remains unclear. Here, we report long-range, large-scale tracing of the axonal projection patterns of OB neurons using two-photon microscopy. Tracer injection into a single glomerulus demonstrated widely distributed mitral/tufted cell axonal projections on the lateroventral surface of the mouse brain, including the anterior/posterior piriform cortex (PC and olfactory tubercle (OT. We noted two distinct groups of labeled axons: PC-orienting axons and OT-orienting axons. Each group occupied distinct parts of the lateral olfactory tract. PC-orienting axons projected axon collaterals to a wide area of the PC but only a few collaterals to the OT. OT-orienting axons densely projected axon collaterals primarily to the anterolateral OT (alOT. Different colored dye injections into the superficial and deep portions of the OB external plexiform layer revealed that the PC-orienting axon populations originated in presumed mitral cells and the OT-orienting axons in presumed tufted cells. These data suggest that although mitral and tufted cells receive similar odor signals from a shared glomerulus, they process the odor information in different ways and send their output to different higher brain centers via the PC and alOT.

  10. Which solvent for olfactory testing?

    Science.gov (United States)

    Philpott, C M; Goodenough, P C; Wolstenholme, C R; Murty, G E

    2004-12-01

    The physical properties of any carrier can deteriorate over time and thus alter the results in any olfactory test. The aim of this study was to evaluate clinically potential solvents as a clean odourless carrier for olfactory testing. Sweet almond oil, pure coconut oil, pure peach kernel oil, dipropylene glycol, monopropylene glycol, mineral oil and silicone oil were studied. The experimentation was conducted in two parts. First, an olfactory device was used to conduct air through the solvents on a weekly basis using a cohort of six volunteers to assess the perceived odour of each solvent at weekly intervals. Secondly a cross-reference test was performed using small bottled solutions of phenylethyl-alcohol and 1-butanol in 10-fold dilutions to compare any perceived difference in concentrations over a period of 8 weeks. We concluded that mineral oil is the most suitable carrier for the purpose of olfactory testing, possessing many desirable characteristics of an olfactory solvent, and that silicone oil may provide a suitable alternative for odorants with which it is miscible.

  11. Olfactory Receptor Database: a sensory chemoreceptor resource

    OpenAIRE

    Skoufos, Emmanouil; Marenco, Luis; Nadkarni, Prakash M.; Miller, Perry L.; Shepherd, Gordon M.

    2000-01-01

    The Olfactory Receptor Database (ORDB) is a WWW-accessible database that has been expanded from an olfactory receptor resource to a chemoreceptor resource. It stores data on six classes of G-protein-coupled sensory chemoreceptors: (i) olfactory receptor-like proteins, (ii) vomeronasal receptors, (iii) insect olfactory receptors, (iv) worm chemoreceptors, (v) taste papilla receptors and (vi) fungal pheromone receptors. A complementary database of the ligands of these receptors (OdorDB) has bee...

  12. Defining sale ethylene for long term storage of tulip bulbs

    OpenAIRE

    Wild, de, H.P.J.; Peppelenbos, H.W.; Dijkstra, M.H.G.E.; Gude, H.

    2002-01-01

    The maximum ethylene level that can be permitted in storage rooms, without causing damage to tulip bulbs, is not exactly known. Therefore, a zero-tolerance for the presence of ethylene during storage of tulip bulbs is common practice. This results in excessive ventilation and coherent large energy costs. It is questioned whether this is always necessary. In different phases of the storage period the critical levels of ethylene were determined. Bulbs of eight economically important cultivars (...

  13. Olfactory dysfunction in Down's Syndrome.

    Science.gov (United States)

    Murphy, C; Jinich, S

    1996-01-01

    Down's Syndrome subjects over 40 years old show neuropathology similar to that of Alzheimer's disease. The olfactory system is particularly vulnerable in Alzheimer's disease, both anatomically and functionally. Several measures of sensory and cognitive functioning were studied in the older Down's Syndrome patient, with the hypothesis of significant olfactory dysfunction. Participants were 23 Down's subjects, and 23 controls. The Dementia Rating Scale showed mean scores of 103 for Down's subjects and 141 for controls. Down's subjects showed significant deficits in odor detection threshold, odor identification, and odor recognition memory. Normal performance in a taste threshold task, similar to the olfactory threshold task in subject demands, suggested that the Down's syndrome subjects' poor performance was not due to task demands. Deficits in olfaction may provide a sensitive and early indicator of the deterioration and progression of the brain in older subjects with Down's Syndrome.

  14. 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.

  15. [Accessory symptomatology and therapy of Gilles de la Tourette's disease].

    Science.gov (United States)

    Achkova, M; Terziev, D

    1987-01-01

    Eight patients with Gilles de la Tourette's syndrome were examined. They had typical multiple tics and accessory disturbances--impulsive and reactive symptoms. The authors described the classification of accessory symptoms and the therapeutic approaches.

  16. Mrap2 Accessory Linked to Obesity

    OpenAIRE

    Liu, Tiemin; Elmquist, Joel K.; Williams, Kevin W.

    2013-01-01

    Melanocortin receptors are critical modulators of energy balance and glucose homeostasis. Companion studies published in Science (Asai et al., 2013; Sebag et al., 2013) establish a role for melanocortin receptor accessory protein 2 (Mrap2) in regulating melanocortin receptor activity and in the development of obesity in zebrafish, rodents, and humans.

  17. 21 CFR 872.3980 - Endosseous dental implant accessories.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Endosseous dental implant accessories. 872.3980... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3980 Endosseous dental implant accessories. (a) Identification. Endosseous dental implant accessories are manually powered devices...

  18. 21 CFR 878.4700 - Surgical microscope and accessories.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Surgical microscope and accessories. 878.4700 Section 878.4700 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... microscope and accessories. (a) Identification. A surgical microscope and accessories is an AC-powered...

  19. HRCT evaluation of the accessory fissures of the lung

    Energy Technology Data Exchange (ETDEWEB)

    Yildiz, Altan E-mail: ayildiz@mersin.edu.tr; Goelpinar, Fulya; Calikoglu, Mukadder; Duce, Meltem Nass; Oezer, Caner; Apaydin, F. Demir

    2004-03-01

    Introduction: The purpose of this study was to classify the accessory fissures of the lung and to assess their frequency by using high-resolution CT. Methods and patients: HRCT scans of 115 patients were prospectively reviewed. 1 mm thin sections were obtained at 10 mm intervals with a scan time of 1.9 s. The fissure and its relationship to the segmental bronchovascular structures were then evaluated on transverse sections. Results: Forty-four accessory fissures were detected in 35 of 115 patients. The most common accessory fissure was the inferior accessory fissure (12%). The second most common accessory fissure was the left minor fissure (8%). The right superior accessory fissure (5%), the accessory fissure between the medial and lateral segments of the right middle lobe (5%), and the accessory fissure between the superior and inferior segments of the lingula (5%) were seen in equal frequencies. Also, intersegmental accessory fissures, namely the fissure between the anterobasal and laterobasal of both the right (1%) and the left (2%) lower lobes were detected. We found only one subsegmental accessory fissure. Discussion and conclusion: The inferior accessory fissure and the left minor fissure were the most common accessory fissures in our study.

  20. 21 CFR 878.3925 - Plastic surgery kit and accessories.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Plastic surgery kit and accessories. 878.3925... (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Prosthetic Devices § 878.3925 Plastic surgery kit and accessories. (a) Identification. A plastic surgery kit and accessories is a device intended...

  1. 21 CFR 876.5820 - Hemodialysis system and accessories.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hemodialysis system and accessories. 876.5820... (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices § 876.5820 Hemodialysis system and accessories. (a) Identification. A hemodialysis system and accessories is a device that...

  2. 21 CFR 878.4160 - Surgical camera and accessories.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Surgical camera and accessories. 878.4160 Section... (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4160 Surgical camera and accessories. (a) Identification. A surgical camera and accessories is a device intended to be...

  3. Effects of diethyldithiocarbamate on myelin basic protein expression in the rat lateral olfactory tract

    Institute of Scientific and Technical Information of China (English)

    Kun Xiong; He Huang; Hui Wang; Yan Cai; Jing Yang; Jufang Huang; Xuegang Luo

    2009-01-01

    BACKGROUND: Dithiocarbamates can cause demyelination of axons in the peripheral nervous system. Its derivate, diethyldithiocarbamate, is cytotoxic, and causes olfactory mucosal damage and atrophy of the olfactory bulb. However, it is still unclear whether the myelin sheath of the lateral olfactory tract is affected by diethyldithiocarbamate.OBJECTIVE: To investigate the effects of diethyldithiocarbamate on the myelin sheath of the rat lateral olfactory tract. This was done by examining changes in myelin basic protein expression after diethyldithiocarbamate treatment.DESIGN, TIME AND SETTING: A randomized, controlled, animal study was performed at the Laboratory of the Department of Human Anatomy and Neurobiology, Xiangya School of Medicine, Central South University, China from July to November 2007.MATERIALS: A total of 72 Sprague Dawley rats were randomly assigned into a diethyldithiocarbamate group (n=32), a solvent control group (n=32), and a blank control group (n=8). The diethyldithiocarbamate and solvent control groups were separately divided into 3-d, 7-d, 14-d and 28-d survival subgroups, with eight rats in each. Diethyldithiocarbamate (Sigma, USA) and goat anti-myelin basic protein polyclonal antibody (Santa Cruz, USA) were used in this study.METHODS: Rats in the diethyldithiocarbamate and solvent control groups were subcutaneously injected with diethyldithiocarbamate (600 mg/kg) and 0.01 mol/L phosphate buffered saline (600 mg/kg) at the posterior neck, respectively. Rats in the blank control group received no treatment.MAIN OUTCOME MEASURES: Immunohistochemical staining and Western blot assay were used to measure myelin basic protein expression in the rat lateral olfactory tract.RESULTS: Following immunohistochemical staining, myelin basic protein was uniformly distributed in the rat lateral olfactory tract in the blank control and solvent control groups. Western blot assay showed 21.5, 18, 17 and 14 ku positive bands. No significant difference was found

  4. Somatic Embryogenesis in Lily Bulb Scale Cultures

    Institute of Scientific and Technical Information of China (English)

    WANG Shasha; WANG Jingang; FAN Jinping; CHE Daidi

    2008-01-01

    Somatic embryogenesis from lily bulb scales has not been studied in details, although tissue culture methods have been applied to the propagation for decades. The effects of different kinds and concentration of auxins for oriental lily somatic embryogenesis were investigated (Lilium hybrida car. Sorbonne).2,4-dichlorophenoxyacetic acid (2,4-D), thidiazuron (TDZ) and α-naphthaleneacetic acid (NAA) media with benzyladenine(6-BA) and lactalbumin hydrolysate (LH) were used for embryogenic callus in the darkness. The best response onembryogenic callus formation was obtained on MS media supplemented 2, 4-D 2.0 mg·L-1,6-BA 0.5 mg·L-1 and LH 300 mg·L-1. Transfer embryogenic callus to the media with TDZ, 6-BA, kinetin (KT) supplemented 2, 4-D. The highest number of somatic embryos has been produced on medium with 0.5 mg.L-1 2, 4-D and 0.3 mg·L-1 KT. Germinated embryos with shoot axes were changed to MS media with 6-BA 0.5 mg· L-1. The results suggest that in vitro culture of somatic embryogenesis from lily bulb scales can be used for plant regeneration.

  5. Unmasking of the trigemino-accessory reflex in accessory facial anastomosis

    OpenAIRE

    Esteban, A.; Prieto, J.

    1999-01-01

    OBJECTIVE—To evaluate the possible blink reflex responses in facial muscles reinnervated by the accessory nerve.
METHOD—Eleven patients with a complete facial palsy were submitted to a surgical repair by an accessory facial nerve anastomosis (AFA). In this pathological group, blink reflex was studied by means of percutaneous electrical stimulation of the supraorbital nerve and recording from the orbicularis oculi muscle. A control group comprised seven normal people an...

  6. Non‑Azygos Accessory Fissure in Right Upper Lobe Associated with Superior and Inferior Accessory Fissures in Right Lower Lobe

    OpenAIRE

    Thomas Jose Eluvathingal Muttikkal; Chunli Deng

    2012-01-01

    Accessory fissures in the lungs are common congenital variations, usually detected as incidental findings in radiographs or CT scan. Accessory fissures can act as an anatomic barrier to the spread of inflammatory or neoplastic disease, as well as due to the variant anatomy, mimic lesions. It is important to recognize the presence of accessory fissures, as they affect surgical planning of pulmonary lobectomy and segmentectomy. Accessory fissure in the right upper lobe other than due to the ano...

  7. Conservation of garlic bulbs (Allium sativum L. ) by gamma irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, J.; Arranz, T.

    1979-01-01

    The effect of different doses of gamma radiation (from 5 to 30 krad) on the conservation of garlic bulbs during a 12 months period is studied. Irradiations were made at three different times and the best results were obtained with the treatment given during the two months following harvest. During this period, 5 krad are enough to inhibit garlic bulbs sprouting.

  8. Fooling Mother Nature: Forcing Flower Bulbs for Indoor Bloom

    OpenAIRE

    Graine, George; Scoggins, Holly Lynne, 1962-

    2014-01-01

    Think about bulb forcing as an orderly process. This includes choosing the bulb, storing it if necessary, selecting the right size container, determining the potting mix, planting (including fertilizer, water and location), providing a cooling treatment if necessary and after care. Other considerations may be color, fragrance, and timing for seasonal enjoyment of winter or early spring bloom.

  9. The "Brightness Rules" Alternative Conception for Light Bulb Circuits

    Science.gov (United States)

    Bryan, Joel A.; Stuessy, Carol

    2006-01-01

    An alternative conception for the observed differences in light bulb brightness was revealed during an unguided inquiry investigation in which prospective elementary teachers placed identical bulbs in series, parallel, and combination direct current circuits. Classroom observations, document analyses, and video and audio transcriptions led to the…

  10. Defining sale ethylene for long term storage of tulip bulbs

    NARCIS (Netherlands)

    Wild, de H.P.J.; Peppelenbos, H.W.; Dijkstra, M.H.G.E.; Gude, H.

    2002-01-01

    The maximum ethylene level that can be permitted in storage rooms, without causing damage to tulip bulbs, is not exactly known. Therefore, a zero-tolerance for the presence of ethylene during storage of tulip bulbs is common practice. This results in excessive ventilation and coherent large energy c

  11. Conservation of garlic bulbs (allium sativum L.) by gamma irradiation

    International Nuclear Information System (INIS)

    The effect of different doses of gamma radiation (from 5 to 30 krad) on the conservation of garlic bulbs during a 12 months period is studied. Irradiations were made at three different times and the best results were obtained with the treatment given during the two months following harvest. During this period, 5krad are enough to inhibit garlic bulbs sprouting. (author)

  12. An Olfactory Cinema: Smelling Perfume

    Directory of Open Access Journals (Sweden)

    Jiaying Sim

    2014-09-01

    Full Text Available While technological improvements from the era of silent movies to that of sound cinema have altered and continued to affect audience’s cinematic experiences, the question is not so much how technology has increased possibility of a sensory response to cinema, rather, it is one that exposes how such technological changes only underscore the participation of our senses and the body in one’s experience of watching film, highlighting the inherently sensorial nature of the cinematic experience. This paper aims to address the above question through an olfactory cinema, by close analysis of Perfume: The Story of a Murderer (2006 by Tom Tykwer. What is an olfactory cinema, and how can such an approach better our understanding of sensorial aspects found within a cinema that ostensibly favours audio-visual senses? What can we benefit from an olfactory cinema? Perhaps, it is through an olfactory cinema that one may begin to embrace the sensual quality of cinema that has been overshadowed by the naturalized ways of experiencing films solely with our eyes and ears, so much so that we desensitize ourselves to the role our senses play in cinematic experiences altogether

  13. Prevalence of olfactory and other developmental anomalies in patients with central hypogonadotropic hypogonadism

    Directory of Open Access Journals (Sweden)

    Elisa eDella Valle

    2013-06-01

    Full Text Available Introduction: Hypogonadotropic hypogonadism (HH is a heterogenous disease caused by mutations in several genes. Based on the presence of hyposmia/anosmia it is distinguished into Kallmann syndrome and isolated HH. The prevalence of other developmental anomalies is not well established. Methods: We studied 36 patients with HH (31 males, 5 females, mean age 41.5, 9 with familial and 27 with sporadic HH (33 congenital, 3 adult-onset, by physical examination, smell test (BSIT Sensonics, audiometry, renal ultrasound, and magnetic resonance imaging of the olfactory structures. Results: Based on the smell test, patients were classified as normosmic (n=21, 58.3% and hypo/anosmic (n=15, 41.6%. Hypoplasy/agenesis of olfactory bulbs was found in 40% of patients (10/25, (75% hypo/anosmic, 7.6% normosmic, p<0.01, Fisher’s-test. Remarkably, olfactory structures were normal in 2 anosmic patients, while 1 normosmic patient presented a monolateral hypoplastic bulb. Fourteen of 33 patients (42.4% presented neurosensorial hearing loss of various degrees (28.5% hypo/anosmic, 52.6% normosmic, p=NS. Renal ultrasound revealed 27.7% of cases with renal anomalies (26.6% hypo/anosmic, 28.5% normosmic, p=NS. At least one midline defects was found in 50% of the patients (53.3% hypo/anosmic, 47.6% normosmic, p=NS, including abnormal palate, dental anomalies, pectus excavatum, bimanual synkinesis, iris coloboma and absent nasal cartilage. Anamnestically 4/31 patients reported cryptorchidism (25% hypo/anosmic, 5.2% normosmic, p=NS. Conclusions: Hypo-anosmia is significantly related to anatomical anomalies of the olfactory bulbs/tracts but the prevalence of other developmental anomalies, especially midline defects and neurosensorial hearing loss, is high both in HH and Kallmann syndrome and independent of the presence of anosmia/hyposmia. From the clinical standpoint Kallmann syndrome and normosmic HH should be considered as the same complex, developmental disease.

  14. Olfactory sensitivity for six predator odorants in CD-1 mice, human subjects, and spider monkeys.

    Directory of Open Access Journals (Sweden)

    Amir Sarrafchi

    Full Text Available Using a conditioning paradigm, we assessed the olfactory sensitivity of six CD-1 mice (Mus musculus for six sulfur-containing odorants known to be components of the odors of natural predators of the mouse. With all six odorants, the mice discriminated concentrations <0.1 ppm (parts per million from the solvent, and with five of the six odorants the best-scoring animals were even able to detect concentrations <1 ppt (parts per trillion. Four female spider monkeys (Ateles geoffroyi and twelve human subjects (Homo sapiens tested in parallel were found to detect the same six odorants at concentrations <0.01 ppm, and with four of the six odorants the best-scoring animals and subjects even detected concentrations <10 ppt. With all three species, the threshold values obtained here are generally lower than (or in the lower range of those reported for other chemical classes tested previously, suggesting that sulfur-containing odorants may play a special role in olfaction. Across-species comparisons showed that the mice were significantly more sensitive than the human subjects and the spider monkeys with four of the six predator odorants. However, the human subjects were significantly more sensitive than the mice with the remaining two odorants. Human subjects and spider monkeys significantly differed in their sensitivity with only two of the six odorants. These comparisons lend further support to the notion that the number of functional olfactory receptor genes or the relative or absolute size of the olfactory bulbs are poor predictors of a species' olfactory sensitivity. Analysis of odor structure-activity relationships showed that in both mice and human subjects the type of alkyl rest attached to a thietane and the type of oxygen moiety attached to a thiol significantly affected olfactory sensitivity.

  15. Influence of size of onion bulb cv. 'Czerniakowska' on its dormancy, sprouting and rooting

    OpenAIRE

    M. Bielińska-Czarnecka; A. Kępkowa; E. Kielak; E. Zdanowska

    2013-01-01

    Sprouting and rooting of onion bulb explants (bulbs deprived of open and closed shells) and of whole onion bulbs of three sizes, horizontal diameters: 2.5-3.5 cm, 3.6-5.0 cm, 5.1-7.0 cm were studied. During storage the earliest sprouting and rooting of bulb explants and of the whole onion bulbs was observed in small bulbs of diameters: 2.5-3.5, and the latest in large bulbs of 5.1-7.0 cm. The longer the period of storage the larger the amount of sprouted and rooted bulb explants and whole bul...

  16. Distribution of centrifugal neurons targeting the soma clusters of the olfactory midbrain among decapod crustaceans.

    Science.gov (United States)

    Schmidt, M

    1997-03-28

    To determine the distribution of two systems of centrifugal neurons innervating the soma clusters of the olfactory midbrain across decapod crustaceans, brains of the following nine species comprising most infraorders were immunostained with antibodies against dopamine and the neuropeptides substance P and FMRFamide: Macrobrachium rosenbergii, Homarus americanus, Cherax destructor, Orconectes limosus, Procambarus clarkii, Astacus leptodactylus, Carcinus maenas, Eriocheir sinensis and Pagurus bernhardus. One system consisting of several neurons with dopamine-like immunoreactivity that originate in the eyestalk ganglia was present in the four crayfish but not in any other species. These neurons project mainly into the lateral soma clusters (cluster 10) comprising the somata of ascending olfactory projection neurons and innervate very sparsely the medial soma clusters (clusters 9 and 11) containing the somata of local interneurons. In the innervation pattern of the lateral cluster, the dopamine-immunoreactive neurons showed large species-specific differences. The other system comprises a pair of giant neurons with substance P-like immunoreactivity. These neurons have somata in the median protocerebrum of the central brain and major projections into the lateral clusters and the core of the olfactory lobes, the neuropils that are the first synaptic relay in the central olfactory pathway of decapods; minor arborizations are present in the medial clusters. The system of substance P-immunoreactive giant neurons was present and of great morphological similarity in all studied species. Only in one species, the shrimp Macrobrachium rosenbergii, evidence for co-localization of FMRFamide-like with substance P-like immunoreactivity in these neurons was obtained. These and previously collected data indicate that the centrifugal neurons with dopamine-like immunoreactivity may be associated with the presence of an accessory lobe, a second-order neuropil that receives input from the

  17. ACCESSORY SPLEEN: A CLINICALLY RELEVANT ANATOMIC ANOMALY

    OpenAIRE

    Prachi Saffar; Amit Kumar; Ankur

    2016-01-01

    The purpose of our study is to emphasize on the clinical relevance of the presence of accessory spleen. It is not only a well-documented anatomic anomaly, it holds special significance in the differential diagnosis of intra-abdominal tumours and lymphadenopathy. MATERIALS AND METHODS Thirty male cadavers from North Indian population above the age of 60 yrs. were dissected in the Anatomy Department of FMHS, SGT University, Gurgaon, over a period of 5 yrs. (Sep 2010-Aug 2015) and presence...

  18. Differential expression of axon-sorting molecules in mouse olfactory sensory neurons.

    Science.gov (United States)

    Ihara, Naoki; Nakashima, Ai; Hoshina, Naosuke; Ikegaya, Yuji; Takeuchi, Haruki

    2016-08-01

    In the mouse olfactory system, the axons of olfactory sensory neurons that express the same type of odorant receptor (OR) converge to a specific set of glomeruli in the olfactory bulb (OB). It is widely accepted that expressed OR molecules instruct glomerular segregation by regulating the expression of axon-sorting molecules. Although the relationship between the expression of axon-sorting molecules and OR types has been analyzed in detail, those between the expressions of axon-sorting molecules remain to be elucidated. Here we collected the expression profiles of four axon-sorting molecules from a large number of glomeruli in the OB. These molecules demonstrated position-independent mosaic expressions, but their patterns were not identical in the OB. Comparing their expressions identified positive and negative correlations between several pairs of genes even though they showed various expressions. Furthermore, the principal component analysis revealed that the factor loadings in the principal component 1, which explain the largest amount of variation, were most likely to reflect the degree of the cyclic nucleotide-gated (CNG) channel dependence on the expression of axon-sorting molecules. Thus, neural activity generated through the CNG channel is a major component in the generation of a wide variety of expressions of axon-sorting molecules in glomerular segregation. PMID:27207328

  19. Olfactory discrimination ability of South African fur seals (Arctocephalus pusillus) for enantiomers.

    Science.gov (United States)

    Kim, Sunghee; Amundin, Mats; Laska, Matthias

    2013-06-01

    Using a food-rewarded two-choice instrumental conditioning paradigm we assessed the ability of South African fur seals, Arctocephalus pusillus, to discriminate between 12 enantiomeric odor pairs. The results demonstrate that the fur seals as a group were able to discriminate between the optical isomers of carvone, dihydrocarvone, dihydrocarveol, menthol, limonene oxide, α-pinene, fenchone (all p isopulegol, rose oxide, and camphor (all p > 0.05). An analysis of odor structure-activity relationships suggests that a combination of molecular structural properties rather than a single molecular feature may be responsible for the discriminability of enantiomeric odor pairs. A comparison between the discrimination performance of the fur seals and that of other species tested previously on the same set of enantiomers (or subsets thereof) suggests that the olfactory discrimination capabilities of this marine mammal are surprisingly well developed and not generally inferior to that of terrestrial mammals such as human subjects and non-human primates. Further, comparisons suggest that neither the relative nor the absolute size of the olfactory bulbs appear to be reliable predictors of between-species differences in olfactory discrimination capabilities. Taken together, the results of the present study support the notion that the sense of smell may play an important and hitherto underestimated role in regulating the behavior of fur seals. PMID:23011284

  20. 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

    2015-05-01

    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.

  1. Fabrication of Closed Hollow Bulb Obturator Using Thermoplastic Resin Material

    Directory of Open Access Journals (Sweden)

    Bidhan Shrestha

    2015-01-01

    Full Text Available Purpose. Closed hollow bulb obturators are used for the rehabilitation of postmaxillectomy patients. However, the time consuming process, complexity of fabrication, water leakage, and discoloration are notable disadvantages of this technique. This paper describes a clinical report of fabricating closed hollow bulb obturator using a single flask and one time processing method for an acquired maxillary defect. Hard thermoplastic resin sheet has been used for the fabrication of hollow bulb part of the obturator. Method. After fabrication of master cast conventionally, bulb and lid part of the defect were formed separately and joined by autopolymerizing acrylic resin to form one sized smaller hollow body. During packing procedure, the defect area was loaded with heat polymerizing acrylic resin and then previously fabricated smaller hollow body was adapted over it. The whole area was then loaded with heat cure acrylic. Further processes were carried out conventionally. Conclusion. This technique uses single flask which reduces laboratory time and makes the procedure simple. The thickness of hollow bulb can be controlled and light weight closed hollow bulb prosthesis can be fabricated. It also minimizes the disadvantages of closed hollow bulb obturator such as water leakage, bacterial infection, and discoloration.

  2. Fabrication of Closed Hollow Bulb Obturator Using Thermoplastic Resin Material.

    Science.gov (United States)

    Shrestha, Bidhan; Hughes, E Richard; Kumar Singh, Raj; Suwal, Pramita; Parajuli, Prakash Kumar; Shrestha, Pragya; Sharma, Arati; Adhikari, Galav

    2015-01-01

    Purpose. Closed hollow bulb obturators are used for the rehabilitation of postmaxillectomy patients. However, the time consuming process, complexity of fabrication, water leakage, and discoloration are notable disadvantages of this technique. This paper describes a clinical report of fabricating closed hollow bulb obturator using a single flask and one time processing method for an acquired maxillary defect. Hard thermoplastic resin sheet has been used for the fabrication of hollow bulb part of the obturator. Method. After fabrication of master cast conventionally, bulb and lid part of the defect were formed separately and joined by autopolymerizing acrylic resin to form one sized smaller hollow body. During packing procedure, the defect area was loaded with heat polymerizing acrylic resin and then previously fabricated smaller hollow body was adapted over it. The whole area was then loaded with heat cure acrylic. Further processes were carried out conventionally. Conclusion. This technique uses single flask which reduces laboratory time and makes the procedure simple. The thickness of hollow bulb can be controlled and light weight closed hollow bulb prosthesis can be fabricated. It also minimizes the disadvantages of closed hollow bulb obturator such as water leakage, bacterial infection, and discoloration.

  3. 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.

  4. Is TrpM5 a reliable marker for chemosensory cells? Multiple types of microvillous cells in the main olfactory epithelium of mice

    Directory of Open Access Journals (Sweden)

    Finger Thomas E

    2008-12-01

    Full Text Available Abstract Background In the past, ciliated receptor neurons, basal cells, and supporting cells were considered the principal components of the main olfactory epithelium. Several studies reported the presence of microvillous cells but their function is unknown. A recent report showed cells in the main olfactory epithelium that express the transient receptor potential channel TrpM5 claiming that these cells are chemosensory and that TrpM5 is an intrinsic signaling component of mammalian chemosensory organs. We asked whether the TrpM5-positive cells in the olfactory epithelium are microvillous and whether they belong to a chemosensory system, i.e. are olfactory neurons or trigeminally-innervated solitary chemosensory cells. Results We investigated the main olfactory epithelium of mice at the light and electron microscopic level and describe several subpopulations of microvillous cells. The ultrastructure of the microvillous cells reveals at least three morphologically different types two of which express the TrpM5 channel. None of these cells have an axon that projects to the olfactory bulb. Tests with a large panel of cell markers indicate that the TrpM5-positive cells are not sensory since they express neither neuronal markers nor are contacted by trigeminal nerve fibers. Conclusion We conclude that TrpM5 is not a reliable marker for chemosensory cells. The TrpM5-positive cells of the olfactory epithelium are microvillous and may be chemoresponsive albeit not part of the sensory apparatus. Activity of these microvillous cells may however influence functionality of local elements of the olfactory system.

  5. The complete human olfactory subgenome.

    Science.gov (United States)

    Glusman, G; Yanai, I; Rubin, I; Lancet, D

    2001-05-01

    Olfactory receptors likely constitute the largest gene superfamily in the vertebrate genome. Here we present the nearly complete human olfactory subgenome elucidated by mining the genome draft with gene discovery algorithms. Over 900 olfactory receptor genes and pseudogenes (ORs) were identified, two-thirds of which were not annotated previously. The number of extrapolated ORs is in good agreement with previous theoretical predictions. The sequence of at least 63% of the ORs is disrupted by what appears to be a random process of pseudogene formation. ORs constitute 17 gene families, 4 of which contain more than 100 members each. "Fish-like" Class I ORs, previously considered a relic in higher tetrapods, constitute as much as 10% of the human repertoire, all in one large cluster on chromosome 11. Their lower pseudogene fraction suggests a functional significance. ORs are disposed on all human chromosomes except 20 and Y, and nearly 80% are found in clusters of 6-138 genes. A novel comparative cluster analysis was used to trace the evolutionary path that may have led to OR proliferation and diversification throughout the genome. The results of this analysis suggest the following genome expansion history: first, the generation of a "tetrapod-specific" Class II OR cluster on chromosome 11 by local duplication, then a single-step duplication of this cluster to chromosome 1, and finally an avalanche of duplication events out of chromosome 1 to most other chromosomes. The results of the data mining and characterization of ORs can be accessed at the Human Olfactory Receptor Data Exploratorium Web site (http://bioinfo.weizmann.ac.il/HORDE). PMID:11337468

  6. SLEEP AND OLFACTORY CORTICAL PLASTICITY

    Directory of Open Access Journals (Sweden)

    Dylan eBarnes

    2014-04-01

    Full Text Available In many systems, sleep plays a vital role in memory consolidation and synaptic homeostasis. These processes together help store information of biological significance and reset synaptic circuits to facilitate acquisition of information in the future. In this review, we describe recent evidence of sleep-dependent changes in olfactory system structure and function which contribute to odor memory and perception. During slow-wave sleep, the piriform cortex becomes hypo-responsive to odor stimulation and instead displays sharp-wave activity similar to that observed within the hippocampal formation. Furthermore, the functional connectivity between the piriform cortex and other cortical and limbic regions is enhanced during slow-wave sleep compared to waking. This combination of conditions may allow odor memory consolidation to occur during a state of reduced external interference and facilitate association of odor memories with stored hedonic and contextual cues. Evidence consistent with sleep-dependent odor replay within olfactory cortical circuits is presented. These data suggest that both the strength and precision of odor memories is sleep-dependent. The work further emphasizes the critical role of synaptic plasticity and memory in not only odor memory but also basic odor perception. The work also suggests a possible link between sleep disturbances that are frequently co-morbid with a wide range of pathologies including Alzheimer’s disease, schizophrenia and depression and the known olfactory impairments associated with those disorders.

  7. 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.

  8. Suppression of IGF-I signals in neural stem cells enhances neurogenesis and olfactory function during aging.

    Science.gov (United States)

    Chaker, Zayna; Aïd, Saba; Berry, Hugues; Holzenberger, Martin

    2015-10-01

    Downregulation of insulin-like growth factor (IGF) pathways prolongs lifespan in various species, including mammals. Still, the cellular mechanisms by which IGF signaling controls the aging trajectory of individual organs are largely unknown. Here, we asked whether suppression of IGF-I receptor (IGF-1R) in adult stem cells preserves long-term cell replacement, and whether this may prevent age-related functional decline in a regenerating tissue. Using neurogenesis as a paradigm, we showed that conditional knockout of IGF-1R specifically in adult neural stem cells (NSC) maintained youthful characteristics of olfactory bulb neurogenesis within an aging brain. We found that blocking IGF-I signaling in neural precursors increased cumulative neuroblast production and enhanced neuronal integration into the olfactory bulb. This in turn resulted in neuro-anatomical changes that improved olfactory function. Interestingly, mutants also displayed long-term alterations in energy metabolism, possibly related to IGF-1R deletion in NSCs throughout lifespan. We explored Akt and ERK signaling cascades and revealed differential regulation downstream of IGF-1R, with Akt phosphorylation preferentially decreased in IGF-1R(-/-) NSCs within the niche, and ERK pathway downregulated in differentiated neurons of the OB. These challenging experimental results were sustained by data from mathematical modeling, predicting that diminished stimulation of growth is indeed optimal for tissue aging. Thus, inhibiting growth and longevity gene IGF-1R in adult NSCs induced a gain-of-function phenotype during aging, marked by optimized management of cell renewal, and enhanced olfactory sensory function. PMID:26219530

  9. New Penicillium species associated with bulbs and root vegetables

    DEFF Research Database (Denmark)

    Overy, David Patrick; Frisvad, Jens Christian

    2003-01-01

    Taxa of the Penicillium series Corymbifera are known for their strongly fasciculate growth and association with the rhizosphere of vegetables and flower bulbs. Using micromorphology, colony characteristics on various media and chemotaxonomic profiling, P. albocoremium sensu stricto and two new...

  10. Melanocortin receptor accessory proteins in adrenal disease and obesity

    OpenAIRE

    Jackson, David S.; Ramachandrappa, Shwetha; Clark, Adrian J; Chan, Li F.

    2015-01-01

    Melanocortin receptor accessory proteins (MRAPs) are regulators of the melanocortin receptor family. MRAP is an essential accessory factor for the functional expression of the MC2R/ACTH receptor. The importance of MRAP in adrenal gland physiology is demonstrated by the clinical condition familial glucocorticoid deficiency type 2. The role of its paralog melanocortin-2-receptor accessory protein 2 (MRAP2), which is predominantly expressed in the hypothalamus including the paraventricular nucle...

  11. The European Commission‘s Light Bulb Decree: Another Costly Regulation?

    OpenAIRE

    Frondel, Manuel; Lohmann, Steffen

    2011-01-01

    Since September 2009, Regulation 244/2009 of the European Commission enforces the gradual phase-out of incandescent light bulbs. As of September 2012, only energy-efficient lighting sources will be allowed for sale. Among these are halogen light bulbs, light-emitting diodes (LED), or compact fluorescent light bulbs - often referred to as energy-saving light bulbs. The Commission's justification for the phase-out of conventional light bulbs maintains that a reduction in the electricity consume...

  12. Steroid hormone modulation of olfactory processing in the context of socio-sexual behaviors in rodents and humans.

    Science.gov (United States)

    Moffatt, Christopher A

    2003-10-01

    Primer pheromones and other chemosensory cues are important factors governing social interactions and reproductive physiology in many species of mammals. Responses to these chemosignals can vary substantially within and between individuals. This variability can stem, at least in part, from the modulating effects steroid and non-steroid hormones exert on olfactory processing. Such modulation frequently augments or facilitates the effects that prevailing social and environmental conditions have on the reproductive axis. The mechanisms underlying the hormonal regulation of responses to chemosensory cues are diverse. They are in part behavioral, achieved through the modulation of chemoinvestigative behaviors, and in part a product of the modulation of the intrinsic responsiveness of the main and accessory olfactory systems to conspecific, as well as other classes, of chemosignals. The behavioral and non-behavioral effects complement one another to ensure that mating and other reproductive processes are confined to reproductively favorable conditions. PMID:14572914

  13. Accessory sperm: a biomonitor of boar sperm fertilization capacity.

    Science.gov (United States)

    Ardón, Florencia; Evert, Meike; Beyerbach, Martin; Weitze, Karl-Fritz; Waberski, Dagmar

    2005-04-15

    The number of accessory sperm found in the zona pellucida of porcine embryos was correlated to their individual quality and to the embryo quality range found within a single sow. Our goal was to determine whether accessory sperm counts provide semen evaluation with additional, useful information. Accessory sperm count was highest when only normal embryos were found in a given sow and diminished if oocytes or degenerated embryos were present (P<0.01). Within a given sow, normal embryos had higher (P<0.05) accessory sperm counts than degenerated embryos, although not when oocytes were also present. Fertilization capacity of sperm is optimal when only normal embryos are found in a given sow; this capacity is indicated by high accessory sperm counts. A decrease in fertilization capacity is reflected in diminishing accessory sperm counts. The boar had a significant effect (P<0.01) on accessory sperm count, but not on the percentage of normal embryos; this suggests that accessory sperm may be more sensitive indicators of the fertilization capacity of sperm than the percentage of normal embryos. We conclude that accessory sperm count can be used for the detection of compensable defects in sperm and is a valid parameter for assessing sperm fertilization capacity.

  14. Degeneration of the olfactory guanylyl cyclase D gene during primate evolution.

    Directory of Open Access Journals (Sweden)

    Janet M Young

    Full Text Available BACKGROUND: The mammalian olfactory system consists of several subsystems that detect specific sets of chemical cues and underlie a variety of behavioral responses. Within the main olfactory epithelium at least three distinct types of chemosensory neurons can be defined by their expression of unique sets of signal transduction components. In rodents, one set of neurons expresses the olfactory-specific guanylyl cyclase (GC-D gene (Gucy2d, guanylyl cyclase 2d and other cell-type specific molecules. GC-D-positive neurons project their axons to a small group of atypical "necklace" glomeruli in the olfactory bulb, some of which are activated in response to suckling in neonatal rodents and to atmospheric CO2 in adult mice. Because GC-D is a pseudogene in humans, signaling through this system appears to have been lost at some point in primate evolution. PRINCIPAL FINDINGS: Here we used a combination of bioinformatic analysis of trace-archive and genome-assembly data and sequencing of PCR-amplified genomic DNA to determine when during primate evolution the functional gene was lost. Our analysis reveals that GC-D is a pseudogene in a large number of primate species, including apes, Old World and New World monkeys and tarsier. In contrast, the gene appears intact and has evolved under purifying selection in mouse, rat, dog, lemur and bushbaby. CONCLUSIONS: These data suggest that signaling through GC-D-expressing cells was probably compromised more than 40 million years ago, prior to the divergence of New World monkeys from Old World monkeys and apes, and thus cannot be involved in chemosensation in most primates.

  15. Accessory slips of the extensor digiti minimi.

    Science.gov (United States)

    Li, Jing; Mao, Qing Hua

    2014-01-01

    During the educational dissection of a 69-year-old Chinese male cadaver, an extensor digiti minimi (EDM) with five slips on the right hand was discovered. Except for the two slips of the little finger, the two radial slips were inserted into the dorsal aponeurosis of the middle finger and the ring finger, respectively. The middle slip was connected to the junctura tendinum in the fourth intermetacarpal spaces. Variations in this region are of paramount importance for the reconstructive surgeons, who may utilize the accessory slips to restore functional capacity of the fingers. PMID:24970007

  16. Olfactory regulation of mosquito-host interactions

    NARCIS (Netherlands)

    Zwiebel, L.J.; Takken, W.

    2004-01-01

    Mosquitoes that act as disease vectors rely upon olfactory cues to direct several important behaviors that are fundamentally involved in establishing their overall vectorial capacity. Of these, the propensity to select humans for blood feeding is arguably the most important of these olfactory driven

  17. Houseflies : Effects of age on olfactory responses

    NARCIS (Netherlands)

    Kelling, FJ; den Otter, CJ; Sommeijer, MJ; Francke, PJ

    1998-01-01

    The olfactory system of sexually immature 1-day-old flies is already functional. No clear differences exist between the responses of their olfactory cells and those of sexually mature flies to amylacetate, S-methylphenol, 2-pentanone and R(+)-limonene. However, the sensitivity to 1-octen-3-ol is low

  18. Calcium signals in olfactory neurons.

    Science.gov (United States)

    Tareilus, E; Noé, J; Breer, H

    1995-11-01

    Laser scanning confocal microscopy in combination with the fluorescent calcium indicators Fluo-3 and Fura-Red was employed to estimate the intracellular concentration of free calcium ions in individual olfactory receptor neurons and to monitor temporal and spatial changes in the Ca(2+)-level upon stimulation. The chemosensory cells responded to odorants with a significant increase in the calcium concentration, preferentially in the dendritic knob. Applying various stimulation paradigma, it was found that in a population of isolated cells, subsets of receptor neurons display distinct patterns of responsiveness. PMID:7488645

  19. [Examination of the olfactory analyzer].

    Science.gov (United States)

    Domrachev, A A; Afon'kin, V Iu

    2002-01-01

    A method of threshold olfactometry is proposed consisting in the use of three olfactive substances (tincture of valerian, acetic acid, liquid ammonia) in selected concentrations. This allows to investigate the thresholds of certain modality. Each concentration of the olfactive substance is placed into a glass bottle (100 ml) and stored at the temperature 18-20 degrees C. The examination of the state of the olfactory analyzer within a 24-h working day showed stability of threshold olfactometry when the organism is tired. Utilization of threshold olfactometry in some diagnostic areas is shown. PMID:12056163

  20. Calcium signals in olfactory neurons.

    Science.gov (United States)

    Tareilus, E; Noé, J; Breer, H

    1995-11-01

    Laser scanning confocal microscopy in combination with the fluorescent calcium indicators Fluo-3 and Fura-Red was employed to estimate the intracellular concentration of free calcium ions in individual olfactory receptor neurons and to monitor temporal and spatial changes in the Ca(2+)-level upon stimulation. The chemosensory cells responded to odorants with a significant increase in the calcium concentration, preferentially in the dendritic knob. Applying various stimulation paradigma, it was found that in a population of isolated cells, subsets of receptor neurons display distinct patterns of responsiveness.

  1. Effects of olfactory ensheathing cells on the proliferation and differentiation of neural stem cells

    Institute of Scientific and Technical Information of China (English)

    Xuewei Xie; Zhouping Tang; Feng Xu; Na Liu; Zaiwang Li; Suiqiang Zhu; Wei Wang

    2009-01-01

    BACKGROUND: Olfactory ensheathing cells can promote oriented differentiation and proliferation of neural stem cells by cell-secreted neural factors.OBJECTIVE: To observe the effect of olfactory ensheathing cells on the differentiation and proliferation of neural stem cells.DESIGN, TIME AND SETrlNG: Cytology was performed at the Department of Neurology, Tongji Medical College, Huazhong University of Science and Technology, China, from September 2007 to October 2008.MATERIALS: Mouse anti-nestin polyclonal antibody (Chemicon, USA), mouse anti-glial fibrillary acidic protein (GFAP) IgG1, mouse anti-2', 3'-cyclic nucleotide 3'-phosphodiesterase (CNPase) IgG1, mouse anti-Tubulin Class-Ill IgG1 (Neo Markers, USA), Avidin-labeled Cy3 (KPL, USA), and goat anti-mouse IgG1: fluorescein isothiocyanate (FITC) (Serotec, UK) were used in this study.METHODS: Tissues were isolated from the embryonic olfactory bulb and subependymal region of Wistar rats. Serum-free DMEM/F12 culture media was used for co-culture experiments. Neural stem cells were incubated in serum-free or 5% fetal bovine serum-containing DMEM/F12 as controls.MAIN OUTCOME MEASURES: After 7 days of co-culture, neural stem cells and olfactory ensheathing cells underwent immunofluorescent staining for nestin, tubulin, glial fibrillary acidic protein, and CNPase.RESULTS: Olfactory ensheathing cells promoted proliferation and differentiation of neural stem cells into neuron-like cells, astrocytes and oligodendrocytes. The proportion of neuron-like cells was 78.2%, but the proportion of neurons in 5% fetal bovine serum DMEM/F12 was 48.3%. In the serum-free DMEM/F12, neural stem cells contracted, unevenly adhered to the glassware wall, or underwent apoptosis at 7 days.CONCLUSION: Olfactory ensheathing cells promote differentiation of neural stem cells mainly into neuron-like cells, and accelerate proliferation of neural stem cells. The outcome is better compared with serum-free medium or medium containing 5% fetal bovine

  2. A Closer Look at Acid-Base Olfactory Titrations

    Science.gov (United States)

    Neppel, Kerry; Oliver-Hoyo, Maria T.; Queen, Connie; Reed, Nicole

    2005-01-01

    Olfactory titrations using raw onions and eugenol as acid-base indicators are reported. An in-depth investigation on olfactory titrations is presented to include requirements for potential olfactory indicators and protocols for using garlic, onions, and vanillin as acid-base olfactory indicators are tested.

  3. Nasopalatine ducts and flehmen behavior in the mandrill: reevaluating olfactory communication in Old World primates.

    Science.gov (United States)

    Charpentier, Marie J E; Mboumba, Sylvère; Ditsoga, Claude; Drea, Christine M

    2013-07-01

    Compared to other modes of communication, chemical signaling between conspecifics generally has been overlooked in Old World primates, despite the presence in this group of secretory glands and scent-marking behavior, as well as the confirmed production and perception of olfactory signals. In other mammalian species, flehmen is a behavior thought to transport primarily nonvolatile, aqueous-soluble odorants via specialized ducts to the vomeronasal organ (VNO). By contrast, Old World primates are traditionally thought to lack a functional VNO, relying instead on the main olfactory system to process volatile odorants from their environment. Here, in the mandrill (Mandrillus sphinx), we document unusual morphological and behavioral traits that typically are associated with the uptake of conspecific chemical cues for processing by an accessory olfactory system. Notably, we confirmed that both sexes possess open nasopalatine ducts and, in response to the presentation of conspecific odorants, we found that both sexes showed stereotyped behavior consistent with the flehmen response. If, as in other species, flehmen in the mandrill serves to mediate social or reproductive information, we expected its occurrence to vary with characteristics of either the signaler or receiver. Flehmen, particularly in a given male, occurred most often in response to odorants derived from male, as opposed to female, conspecifics. Moreover, odorants derived during the breeding season elicited more flehmen responses than did odorants collected during the birthing season. Lastly, odorants from reproductively cycling females also elicited more responses than did odorants from contracepted females. Although confirming a link between the nasopalatine ducts, flehmen behavior, and olfactory processing in mandrills would require further study, our observations provide new information to suggest anatomical variability within Old World primates, calling further attention to the underappreciated role of

  4. Molecular clock regulates daily α1-2-fucosylation of the neural cell adhesion molecule (NCAM) within mouse secondary olfactory neurons.

    Science.gov (United States)

    Kondoh, Daisuke; Tateno, Hiroaki; Hirabayashi, Jun; Yasumoto, Yuki; Nakao, Reiko; Oishi, Katsutaka

    2014-12-26

    The circadian clock regulates various behavioral and physiological rhythms in mammals. Circadian changes in olfactory functions such as neuronal firing in the olfactory bulb (OB) and olfactory sensitivity have recently been identified, although the underlying molecular mechanisms remain unknown. We analyzed the temporal profiles of glycan structures in the mouse OB using a high-density microarray that includes 96 lectins, because glycoconjugates play important roles in the nervous system such as neurite outgrowth and synaptogenesis. Sixteen lectin signals significantly fluctuated in the OB, and the intensity of all three that had high affinity for α1-2-fucose (α1-2Fuc) glycan in the microarray was higher during the nighttime. Histochemical analysis revealed that α1-2Fuc glycan is located in a diurnal manner in the lateral olfactory tract that comprises axon bundles of secondary olfactory neurons. The amount of α1-2Fuc glycan associated with the major target glycoprotein neural cell adhesion molecule (NCAM) varied in a diurnal fashion, although the mRNA and protein expression of Ncam1 did not. The mRNA and protein expression of Fut1, a α1-2-specific fucosyltransferase gene, was diurnal in the OB. Daily fluctuation of the α1-2Fuc glycan was obviously damped in homozygous Clock mutant mice with disrupted diurnal Fut1 expression, suggesting that the molecular clock governs rhythmic α1-2-fucosylation in secondary olfactory neurons. These findings suggest the possibility that the molecular clock is involved in the diurnal regulation of olfaction via α1-2-fucosylation in the olfactory system.

  5. 46 CFR 98.25-40 - Valves, fittings, and accessories.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Valves, fittings, and accessories. 98.25-40 Section 98... Anhydrous Ammonia in Bulk § 98.25-40 Valves, fittings, and accessories. (a) All valves, flanges, fittings... Engineering) of this chapter. Valves shall be fitted with noncorrosive material suitable for ammonia...

  6. 21 CFR 876.5630 - Peritoneal dialysis system and accessories.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Peritoneal dialysis system and accessories. 876... Peritoneal dialysis system and accessories. (a) Identification. (1) A peritoneal dialysis system and... peritoneal dialysis, a source of dialysate, and, in some cases, a water purification mechanism. After...

  7. 26 CFR 48.4161(a)-3 - Parts and accessories.

    Science.gov (United States)

    2010-04-01

    ....4161(a)-3 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) MISCELLANEOUS EXCISE TAXES MANUFACTURERS AND RETAILERS EXCISE TAXES Sporting Goods § 48.4161(a)-3 Parts and accessories. (a) In general. The tax attaches with respect to parts and accessories for articles specified...

  8. Burkholderia pseudomallei penetrates the brain via destruction of the olfactory and trigeminal nerves: implications for the pathogenesis of neurological melioidosis.

    Science.gov (United States)

    St John, James A; Ekberg, Jenny A K; Dando, Samantha J; Meedeniya, Adrian C B; Horton, Rachel E; Batzloff, Michael; Owen, Suzzanne J; Holt, Stephanie; Peak, Ian R; Ulett, Glen C; Mackay-Sim, Alan; Beacham, Ifor R

    2014-01-01

    ABSTRACT Melioidosis is a potentially fatal disease that is endemic to tropical northern Australia and Southeast Asia, with a mortality rate of 14 to 50%. The bacterium Burkholderia pseudomallei is the causative agent which infects numerous parts of the human body, including the brain, which results in the neurological manifestation of melioidosis. The olfactory nerve constitutes a direct conduit from the nasal cavity into the brain, and we have previously reported that B. pseudomallei can colonize this nerve in mice. We have now investigated in detail the mechanism by which the bacteria penetrate the olfactory and trigeminal nerves within the nasal cavity and infect the brain. We found that the olfactory epithelium responded to intranasal B. pseudomallei infection by widespread crenellation followed by disintegration of the neuronal layer to expose the underlying basal layer, which the bacteria then colonized. With the loss of the neuronal cell bodies, olfactory axons also degenerated, and the bacteria then migrated through the now-open conduit of the olfactory nerves. Using immunohistochemistry, we demonstrated that B. pseudomallei migrated through the cribriform plate via the olfactory nerves to enter the outer layer of the olfactory bulb in the brain within 24 h. We also found that the bacteria colonized the thin respiratory epithelium in the nasal cavity and then rapidly migrated along the underlying trigeminal nerve to penetrate the cranial cavity. These results demonstrate that B. pseudomallei invasion of the nerves of the nasal cavity leads to direct infection of the brain and bypasses the blood-brain barrier. IMPORTANCE Melioidosis is a potentially fatal tropical disease that is endemic to northern Australia and Southeast Asia. It is caused by the bacterium Burkholderia pseudomallei, which can infect many organs of the body, including the brain, and results in neurological symptoms. The pathway by which the bacteria can penetrate the brain is unknown, and

  9. [Odor sensing system and olfactory display].

    Science.gov (United States)

    Nakamoto, Takamichi

    2014-01-01

    In this review, an odor sensing system and an olfactory display are introduced into people in pharmacy. An odor sensing system consists of an array of sensors with partially overlapping specificities and pattern recognition technique. One of examples of odor sensing systems is a halitosis sensor which quantifies the mixture composition of three volatile sulfide compounds. A halitosis sensor was realized using a preconcentrator to raise sensitivity and an electrochemical sensor array to suppress the influence of humidity. Partial least squares (PLS) method was used to quantify the mixture composition. The experiment reveals that the sufficient accuracy was obtained. Moreover, the olfactory display, which present scents to human noses, is explained. A multi-component olfactory display enables the presentation of a variety of smells. The two types of multi-component olfactory display are described. The first one uses many solenoid valves with high speed switching. The valve ON frequency determines the concentration of the corresponding odor component. The latter one consists of miniaturized liquid pumps and a surface acoustic wave (SAW) atomizer. It enables the wearable olfactory display without smell persistence. Finally, the application of the olfactory display is demonstrated. Virtual ice cream shop with scents was made as a content of interactive art. People can enjoy harmony among vision, audition and olfaction. In conclusion, both odor sensing system and olfactory display can contribute to the field of human health care.

  10. Radioinhibition process in Argentinian garlic and onion bulbs

    Science.gov (United States)

    Curzio, O. A.; Croci, C. A.

    Technological aspects of garlic and onion bulbs subjected to the radioinhibition process and extended storage under warehouse conditions were studied. Garlic and onion of the "Colorado" and "Valenciana sintética 14" varieties respectively, were irradiated in dormancy period with an average dose of 50.0 Gy of 60Co gamma rays and kept in storage up to ten months post-harvest. Throughout the control period (180-300 days post-harvest) obvious benefits were attained as to reducing the weight loss and increasing the percentage of marketable bulbs. In general, the irradiated bulbs were superior to the non-irradiated ones with regard to the external aspect, firmness and internal aspect, while the odor of the bulbs was not affected by the process. The radioinhibition process does not seem to affect adversely the levels of dry matter, carbohydrates and ascorbic acid as well as the acidity in onion bulbs. In two marketing trials a very favourable reception was perceived in the consumer public regarding the quality of the products. These studies have promoted the construction of a multipurpose irradiation facility in the Universidad Nacional del Sur for the development of the radiation processing technology.

  11. The GLOBE Soil Moisture Campaign's Light Bulb Oven

    Science.gov (United States)

    Whitaker, M. P.; Tietema, D.; Ferre, T. P.; Nijssen, B.; Washburne, J.

    2003-12-01

    The GLOBE Soil Moisture Campaign (SMC) (www.hwr.arizona.edu/globe/sci/SM/SMC) has developed a light bulb oven to provide a low budget, low-technology method for drying soil samples. Three different soils were used to compare the ability of the light bulb oven to dry soils against a standard laboratory convection oven. The soils were: 1) a very fine sandy loam (the "Gila" soil); 2) a silty clay (the "Pima" soil); and 3) a sandy soil (the "Sonoran" soil). A large batch of each soil was wetted uniformly in the laboratory. Twelve samples of each soil were placed in the light bulb oven and twelve samples were placed in the standard oven. The average gravimetric soil moisture of the Gila soil was 0.214 g/cm3 for both ovens; the average Pima soil moisture was 0.332 g/cm3 and 0.331 g/cm3 for the traditional and light bulb ovens, respectively; and the Sonoran soil moisture was 0.077 g/cm3 for both ovens. These results demonstrate that the low technology light-bulb oven was able to dry the soil samples as well as a standard laboratory oven, offering the ability to make gravimetric water content measurements when a relatively expensive drying oven is not available.

  12. [Occurrence and structure of accessory adrenal glands in Wistar rats].

    Science.gov (United States)

    Schwabedal, P E; Partenheimer, U

    1983-01-01

    In complete series of histological sections through the entire abdomen of one normal Wistar-rat, one untreated and two bilaterally adrenalectomized, spontaneously hypertensive Wistar-rats accessory suprarenal glands were found in each case. The detailed findings in the various groups of animals investigated were as follows: (1) In the normal animal 10 accessory suprarenal glands were present. They consisted of tiny aggregates of cortical cells and were surrounded by a thin layer of collageneous fibers. The diameters of the accessory suprarenal complexes were in the order of 0.3 mm. (2) In the untreated, spontaneously hypertensive rat three accessory suprarenal glands were found. However, in contrast to what was seen in the normal rat, these complexes were larger and had diameters of up to 1 mm. Some of these accessory suprarenal glands consisted almost exclusively of small, chromophobe cells, whereas in others a rim of such cells was seen to surround a central core of larger and more acidophile cortical cells. There were few and collapsed capillaries. (3) In the bilaterally adrenalectomized, spontaneously hypertensive rats three, respectively four, accessory suprarenal glands were found. They were situated in the retroperitoneum and partly within the adipose capsule of the kidney but never in the place of the exstirpated main suprarenal glands. In one case an accessory gland was found within the fibrous capsule of the kidney and seen to compress the renal parenchyma. In the bilaterally adrenalectomized animals the average diameters of the accessory glands were larger than in the other groups reaching values of up to 5 mm. At least in both animals one of the accessory glands had a diameter comparable to that of the normal suprarenal gland of an untreated animal. The capillaries were dilated and their number was increased in comparison to what was seen in the other groups. In certain regions the cortical tissue of the accessory glands had an appearance resembling

  13. [Graphic method of recording olfactory disorders].

    Science.gov (United States)

    Bariliak, R A; Kitsera, A E

    1976-01-01

    The authors present a method of recording results of threshold olfactometry for substances of different neuroreceptive response (olfactory, olfactive-trigeminal and olfactive-glossopharyngeal) in the form of olfactograms. The use of a unit for comparative evaluation of the olfactory function (deciodor) made it possible to get a unit horizontal zero line on the olfactogram. The authors demonstrate olfactograms of patients with various olfactory disorders. They consider that the method of graphic recording results of comparative threshold olfactometry is a valuable differential-diagnostic test.

  14. Biomimetic Olfactory Sensing System Based on Brain-Machine Interface and Olfactory Decoding%基于脑-机接口和嗅觉解码的仿生气味识别系统

    Institute of Scientific and Technical Information of China (English)

    董琪; 秦臻; 胡靓; 庄柳静; 张斌; 王平

    2015-01-01

    Mammalian olfactory systems have merits of higher sensitivity, selectivity and faster response than current electronic nose systems based on chemical sensor array in odor recognition. The purpose of this study is to develop a biomimetic olfactory sensing system based on brain-machine interface technology for odor detection in vivo electrophysiological measurements of olfactory bulb. In this work, extracellular potentials of mitral/tufted cells in olfactory bulb 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 in both temporal features and rate features when stimulated by different small molecular odorants. Odors were classified by an algorithm based on population vector similarity and support vector machine. The results suggest that the novel bioelectonic nose is sensitive to odorant stimuli. With the development of 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.%为了探讨利用生物嗅觉传感系统进行气味识别的可行性,提出了一种基于脑-机接口的仿生气味识别系统。该系统利用大鼠嗅觉感受细胞作为气味敏感传感单元,使用16通道植入式微丝电极记录和分析具有气味刺激特征的嗅球僧帽细胞电位响应信号。实验结果显示,该系统对气味具有高度敏感性,通过一定模式识别处理算法,不同的气味刺激具有较好的区分性,证明了该系统有望应用于气味的检测和识别。

  15. Roles of sex and gonadal steroids in mammalian pheromonal communication.

    Science.gov (United States)

    Baum, Michael J; Bakker, Julie

    2013-10-01

    A brain circuit (the accessory olfactory system) that originates in the vomeronasal organ (VNO) and includes the accessory olfactory bulb (AOB) plus additional forebrain regions mediates many of the effects of pheromones, typically comprised of a variety of non-volatile and volatile compounds, on aspects of social behavior. A second, parallel circuit (the main olfactory system) that originates in the main olfactory epithelium (MOE) and includes the main olfactory bulb (MOB) has also been shown to detect volatile pheromones from conspecifics. Studies are reviewed that point to specific roles of several different steroids and their water-soluble metabolites as putative pheromones. Other studies are reviewed that establish an adult, 'activational' role of circulating sex hormones along with sex differences in the detection and/or processing of non-steroidal pheromones by these two olfactory circuits. Persisting questions about the role of sex steroids in pheromonal processing are posed for future investigation. PMID:23872334

  16. Cladistic Analysis of Olfactory and Vomeronasal Systems

    OpenAIRE

    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...

  17. Cladistic analysis of olfactory and vomeronasal systems

    OpenAIRE

    Alino eMartinez-Marcos

    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...

  18. Functional neuroanatomy of Drosophila olfactory memory formation

    OpenAIRE

    Guven-Ozkan, Tugba; Davis, Ronald L.

    2014-01-01

    New approaches, techniques and tools invented over the last decade and a half have revolutionized the functional dissection of neural circuitry underlying Drosophila learning. The new methodologies have been used aggressively by researchers attempting to answer three critical questions about olfactory memories formed with appetitive and aversive reinforcers: (1) Which neurons within the olfactory nervous system mediate the acquisition of memory? (2) What is the complete neural circuitry exten...

  19. Olfactory metaphors in the online environment

    OpenAIRE

    Alina Ţenescu

    2015-01-01

    The main objective of this paper is to analyze the main aspects of the olfactory metaphor in online perfume reviews and to identify its main characteristics in the non-specialized perfume discourse. Using as a starting point the approach whose overall view is guided by conceptual metaphor theory, we will identify, analyze and classify the main elements of the metaphorical schema associated with the olfactory metaphor related to fragrance perception and description. We will illustrate this cat...

  20. Depletion of biogenic amines and enhancement of cholinergic activity in the olfactory bulb and central olfactory connections with chronic methedrine intoxication

    Directory of Open Access Journals (Sweden)

    O. Duarte-Escalante

    1970-06-01

    Full Text Available Em seqüência a estudos anteriores os autores visam, neste relato, a apresentar as alterações histoquímicas que ocorrem no sistema olfatório de gatos nos quais se desenvolveu nítida estereotipia de fungação (sniffing após administração prolongada de metedrina. Foram intoxicados 12 gatos mediante injeções diárias, durante 10 dias, de doses progressivas de metedrina. Os tecidos a examinar (bulbos olfatórios e suas conexões centrais foram preparados histoquimicamente para demonstrar a fluorescência das aminas biogênicas e reações colinérgicas. Mediante algumas modificações à metodologia recomendada por outros pesquisadores, os autores puderam demonstrar a presença de monoaminas e de acetilcolina no bulbo olfatório e de grupos de fibras adrenérgicas curtas e multi-ramificadas que parecem ser conectadas com os neurônios fluorescentes do bulbo olfatório, a partir de onde estabelecem conexões, pelo tracto olfatório medial, com os neurônios do septum e, pelo tracto olfatório lateral, com os neurônios do complexo amigdalóide.

  1. The association of hallux limitus with the accessory navicular.

    Science.gov (United States)

    Evans, R D Lee; Averett, Ryan; Sanders, Stephanie

    2002-06-01

    Hallux limitus is one of the most prevalent, debilitating disorders of the first metatarsophalangeal joint, and it has many proposed etiologies. This article reviews these etiologies, focusing primarily on the pes planus foot. The pes planus foot type is often associated with symptomatic hallux limitus and the accessory navicular. This article discusses this correlation, although a causal relationship has not been proven. The prevalence and classification of the accessory navicular are also discussed. Clinical cases involving symptomatic hallux limitus occurring concomitantly with an accessory navicular are reviewed, including radiographic findings, symptoms, and surgical treatment. PMID:12070237

  2. Perineal Accessory Scrotum with Congenital Lipoma: A Rare Case Report

    Directory of Open Access Journals (Sweden)

    Souvik Chatterjee

    2012-01-01

    Full Text Available A case of accessory scrotum in a 1-year-old boy is reported because of its rarity. A boy presented with a tumor mass attached with scrotum-like skin on its tip in the right side of perineum between the scrotum and anus. Both testes had descended into the scrotum. There was no other urological anomaly. Histological findings of the tumor indicated perineal lipoma, and the scrotum-like portion accessory scrotum. An overview of sequences during the normal development of male external genitalia has been provided and the deranged mechanism resulting in this anomaly has been reviewed with hypothesis regarding etiology of accessory scrotum.

  3. Contrast enhancement of stimulus intermittency in a primary olfactory network and its behavioral significance

    Directory of Open Access Journals (Sweden)

    Lei Hong

    2009-02-01

    Full Text Available Abstract Background An animal navigating to an unseen odor source must accurately resolve the spatiotemporal distribution of that stimulus in order to express appropriate upwind flight behavior. Intermittency of natural odor plumes, caused by air turbulence, is critically important for many insects, including the hawkmoth, Manduca sexta, for odor-modulated search behavior to an odor source. When a moth's antennae receive intermittent odor stimulation, the projection neurons (PNs in the primary olfactory centers (the antennal lobes, which are analogous to the olfactory bulbs of vertebrates, generate discrete bursts of action potentials separated by periods of inhibition, suggesting that the PNs may use the binary burst/non-burst neural patterns to resolve and enhance the intermittency of the stimulus encountered in the odor plume. Results We tested this hypothesis first by establishing that bicuculline methiodide reliably and reversibly disrupted the ability of PNs to produce bursting response patterns. Behavioral studies, in turn, demonstrated that after injecting this drug into the antennal lobe at the effective concentration used in the physiological experiments animals could no longer efficiently locate the odor source, even though they had detected the odor signal. Conclusions Our results establish a direct link between the bursting response pattern of PNs and the odor-tracking behavior of the moth, demonstrating the behavioral significance of resolving the dynamics of a natural odor stimulus in antennal lobe circuits.

  4. Immunohistochemical analysis for G protein in the olfactory organs of soft-shelled turtle, Pelodiscus sinensis

    Science.gov (United States)

    NAKAMUTA, Shoko; YOKOSUKA, Makoto; TANIGUCHI, Kazumi; YAMAMOTO, Yoshio; NAKAMUTA, Nobuaki

    2015-01-01

    In turtles, the epithelia lining the upper and lower chambers of the nasal cavity project axons to the ventral and dorsal parts of the olfactory bulbs, respectively. In a semi-aquatic soft-shelled turtle, Pelodiscus sinensis, more than 1,000 odorant receptor genes have been found, but it is not known where they are expressed. In this study, we aimed to clarify the distribution of cells expressing these genes in the olfactory organs of soft-shelled turtles. Immunoreactions for the Gαolf, the α subunit of G protein coupled to the odorant receptors, were detected on the surface of epithelia lining both the upper and lower chambers of the nasal cavity. The receptor cells in the epithelium of both chambers possessed cilia on the tip of their dendrites, whereas microvillous, non-ciliated, receptor cells were not found. These data suggest that the odorant receptor genes are expressed by the ciliated receptor cells in the upper and lower chamber epithelia. Precise location of the vomeronasal epithelium is not known at present. PMID:26440778

  5. Constitutively expressed Protocadherin-α regulates the coalescence and elimination of homotypic olfactory axons through its cytoplasmic region

    Directory of Open Access Journals (Sweden)

    Sonoko eHasegawa

    2012-10-01

    Full Text Available Olfactory sensory neuron (OSN axons coalesce into specific glomeruli in the olfactory bulb (OB according to their odorant receptor (OR expression. Several guidance molecules enhance the coalescence of homotypic OSN projections, in an OR-specific- and neural-activity-dependent manner. However, the mechanism by which homotypic OSN axons are organized into glomeruli is unsolved. We previously reported that the clustered protocadherin-α (Pcdh-α family of diverse cadherin-related molecules plays roles in the coalescence and elimination of homotypic OSN axons throughout development. Here we showed that the elimination of small ectopic homotypic glomeruli required the constitutive expression of a Pcdh-α isoform and Pcdh-α’s cytoplasmic region, but not OR specificity or neural activity. These results suggest that Pcdh-α proteins provide a cytoplasmic signal to regulate repulsive activity for homotypic OSN axons independently of OR expression and neural activity. The counterbalancing effect of Pcdh-α proteins for the axonal coalescence mechanisms mediated by other olfactory guidance molecules indicate a possible mechanism for the organization of homotypic OSN axons into glomeruli during development.

  6. Structural olfactory nerve changes in patients suffering from idiopathic intracranial hypertension.

    Directory of Open Access Journals (Sweden)

    Christoph Schmidt

    Full Text Available BACKGROUND: Complications of idiopathic intracranial hypertension (IIH are usually caused by elevated intracranial pressure (ICP. In a similar way as in the optic nerve, elevated ICP could also compromise the olfactory nerve system. On the other side, there is growing evidence that an extensive lymphatic network system around the olfactory nerves could be disturbed in cerebrospinal fluid disorders like IIH. The hypothesis that patients with IIH suffer from hyposmia has been suggested in the past. However, this has not been proven in clinical studies yet. This pilot study investigates whether structural changes of the olfactory nerve system can be detected in patients with IIH. METHODOLOGY/PRINCIPAL FINDINGS: Twenty-three patients with IIH and 23 matched controls were included. Olfactory bulb volume (OBV and sulcus olfactorius (OS depth were calculated by magnetic resonance techniques. While mean values of total OBV (128.7±38.4 vs. 130.0±32.6 mm(3, p=0.90 and mean OS depth (8.5±1.2 vs. 8.6±1.1 mm, p=0.91 were similar in both groups, Pearson correlation showed that patients with a shorter medical history IIH revealed a smaller OBV (r=0.53, p<0.01. In untreated symptomatic patients (n=7, the effect was greater (r=0.76, p<0.05. Patients who suffered from IIH for less than one year (n=8, total OBV was significantly smaller than in matched controls (116.6±24.3 vs. 149.3±22.2 mm(3, p=0.01. IIH patients with visual disturbances (n=21 revealed a lower OS depth than patients without (8.3±0.9 vs. 10.8±1.0 mm, p<0.01. CONCLUSIONS/SIGNIFICANCE: The results suggest that morphological changes of the olfactory nerve system could be present in IIH patients at an early stage of disease.

  7. 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

  8. Olfactory processing and odor specificity: a meta-analysis of menstrual cycle variation in olfactory sensitivity

    Directory of Open Access Journals (Sweden)

    Martinec Nováková Lenka

    2014-12-01

    Full Text Available Cycle-correlated variation in olfactory threshold, with women becoming more sensitive to odors mid-cycle, is somewhat supported by the literature but the evidence is not entirely consistent, with several studies finding no, or mixed, effects. It has been argued that cyclic shifts in olfactory threshold might be limited to odors relevant to the mating context.

  9. Special branches: organic greenhouse production, bulbs, ornamentals and aquaculture

    NARCIS (Netherlands)

    Sukkel, W.; Hommes, M.; Meijer, R.J.M.

    2009-01-01

    Organic production methods are gaining ground in Dutch specialised production branches. Interest is growing among greenhouse horticulturalists and growers of flower bulbs, ornamentals and mushrooms. In organic horticulture Dutch research is unique in the world in thinking up innovative concepts and

  10. Experimental characterization of CFL bulbs for power quality assessment

    NARCIS (Netherlands)

    Vugt, van P.; Timens, R.B.; Stievano, I.S.; Leferink, F.B.J.; Canavero, F.G.

    2013-01-01

    This paper presents the results of a systematic set of voltage and current transient measurements aimed at characterizing the electrical behavior of a typical energy efficient compact fluorescent light bulb. The considered device represents a well-known example of a number of nonlinear loads that ar

  11. On the Intensity Profile of Electric Lamps and Light Bulbs

    Science.gov (United States)

    Bacalla, Xavier; Salumbides, Edcel John

    2013-01-01

    We demonstrate that the time profile of the light intensity from domestic lighting sources exhibits simple yet interesting properties that foster lively student discussions. We monitor the light intensity of an industrial fluorescent lamp (also known as TL) and an incandescent bulb using a photodetector connected to an oscilloscope. The light…

  12. The "Green Lab": Power Consumption by Commercial Light Bulbs

    Science.gov (United States)

    Einsporn, James A.; Zhou, Andrew F.

    2011-01-01

    Going "green" is a slogan that is very contemporary, both with industry and in the political arena. Choosing more energy-efficient devices is one way homeowners can "go green." A simple method is to change home lighting from hot incandescent bulbs to compact fluorescent lights (CFLs). But do they really save energy? How do their illuminations…

  13. Neural correlates of behavioural olfactory sensitivity changes seasonally in European starlings.

    Directory of Open Access Journals (Sweden)

    Geert De Groof

    Full Text Available BACKGROUND: Possibly due to the small size of the olfactory bulb (OB as compared to rodents, it was generally believed that songbirds lack a well-developed sense of smell. This belief was recently revised by several studies showing that various bird species, including passerines, use olfaction in many respects of life. During courtship and nest building, male European starlings (Sturnus vulgaris incorporate aromatic herbs that are rich in volatile compounds (e.g., milfoil, Achillea millefolium into the nests and they use olfactory cues to identify these plants. Interestingly, European starlings show seasonal differences in their ability to respond to odour cues: odour sensitivity peaks during nest-building in the spring, but is almost non-existent during the non-breeding season. METHODOLOGY/PRINCIPAL FINDINGS: This study used repeated in vivo Manganese-enhanced MRI to quantify for the first time possible seasonal changes in the anatomy and activity of the OB in starling brains. We demonstrated that the OB of the starling exhibits a functional seasonal plasticity of certain plant odour specificity and that the OB is only able to detect milfoil odour during the breeding season. Volumetric analysis showed that this seasonal change in activity is not linked to a change in OB volume. By subsequently experimentally elevating testosterone (T in half of the males during the non-breeding season we showed that the OB volume was increased compared to controls. CONCLUSIONS/SIGNIFICANCE: By investigating the neural substrate of seasonal olfactory sensitivity changes we show that the starlings' OB loses its ability during the non-breeding season to detect a natural odour of a plant preferred as green nest material by male starlings. We found that testosterone, applied during the non-breeding season, does not restore the discriminatory ability of the OB but has an influence on its size.

  14. ISO and EIGA standards for cryogenic vessels and accessories

    CERN Document Server

    CERN. Geneva

    2016-01-01

    The EIGA/WG 6’s scope is cryogenic vessels and accessories, including their design, material compatibility, operational requirements and periodical inspection. The specific responsibilities include monitoring international standardization (ISO, CEN) and regulations (UN, TPED, PED...

  15. Giant Accessory Right-Sided Suprarenal Spleen in Thalassaemia

    Directory of Open Access Journals (Sweden)

    A. Arra

    2013-01-01

    Full Text Available An accessory spleen is defined as ectopic splenic tissue that develops due to failure of fusion of cells during embryonic development as they migrate from the midline to the left upper quadrant. While benign, complications may arise which include trauma, torsion, or infarction of the ectopic tissue. Additionally, patients who have had a splenectomy secondary to treatment for previous pathology such as a haematological malignancy or idiopathic thrombocytopenia purpura may experience persistent symptoms due to the accessory splenic tissue. The presence of an accessory spleen is therefore of significant diagnostic and therapeutic importance. To the best of the authors' knowledge, this case is the second and largest reported case of a giant right suprarenal accessory spleen and highlights the difficulty in differentiation of these masses from malignant adrenal tumours.

  16. An incidental finding of the accessory inferior thyroid artery

    OpenAIRE

    Sedy J

    2008-01-01

    We report a case of an incidental finding of the right accessory inferior thyroid artery, emerging from the thyrocervical trunk together with a typical inferior thyroid artery, present in a normal position. On the left side, only single inferior thyroid artery was present. Only one inferior thyroid vein was found on each side. The accessory inferior thyroid artery entered the thyroid gland approximately 1 cm above the normal inferior thyroid, above the superior parathyroid gland. Although acc...

  17. Accessory Nerve Schwannoma Containing Multiple Calcifed Foci: Unusual Presentation

    OpenAIRE

    Leila Aghaghazvini; Habib Mazaher; Hashem Sharifian; Shirin Aghaghazvini

    2009-01-01

    "nIntroduction: Schwannomas are benign neural tumors which arise from the nerve sheath. Schwannomas of the accessory nerve are rare lesions. The clinical presentation of cranial nerve XI schwannomas relates to their location and extent: intracranial, jugular foramen, upper neck, or cervical spine. The extra cranial form is the least common reported. Calcified accessory schwannoma is rare. These lesions most often occur in the third to sixth decades of life. These tumors are slightly more...

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

    Science.gov (United States)

    Jung, Yong Gi; Lane, Andrew P.

    2016-01-01

    Objective To determine the effect of a soluble human tumor necrosis factor alpha (TNF-α) receptor blocker (Etanercept) on an inducible olfactory inflammation (IOI) mouse model Study Design An in vivo study using a transgenic mouse model Setting Research laboratory Subjects and Methods To study the impact of chronic inflammation on the olfactory system, a transgenic mouse model of chronic rhinosinusitis (CRS)-associated olfactory loss was utilized (IOI mouse), expressing TNF-α in a temporally-controlled fashion specifically within the olfactory epithelium. In one group of mice (n=4), Etanercept was injected intraperitoneally (100 µg/dose, 3 times/week) concurrent with a 2-week period of TNF-α expression. A second group of mice (n=2) underwent induction of TNF-α expression for 8 weeks, with Etanercept treatment administered during the final 2 weeks of inflammation. Olfactory function was assayed by elecro-olfactogram (EOG), and olfactory tissue was processed for histology and immunohistochemical staining. Each group was compared with equal number of control group. Results Compared to non-treated IOI mice, Etanercept -treated IOI mice showed significantly improved EOG responses after 2 weeks (p<0.001). After 8 weeks of induced inflammation, there was massive loss of olfactory epithelium and no EOG response in non-treated IOI mice. However, in Etanercept - treated mice, regeneration of olfactory epithelium was observed. Conclusion Concomitant administration of Etanercept in IOI mice results in interruption of TNF-α-induced olfactory loss and induction of neuroepithelial regeneration. This demonstrates that Etanercept has potential utility as a tool for elucidating the role of TNF-α in other olfactory inflammation models. PMID:26932943

  19. Female mice lacking chol