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Sample records for olfactory stimulus 1-octanol

  1. The C. elegans D2-Like Dopamine Receptor DOP-3 Decreases Behavioral Sensitivity to the Olfactory Stimulus 1-Octanol

    PubMed Central

    Ezak, Meredith J.; Ferkey, Denise M.

    2010-01-01

    We previously found that dopamine signaling modulates the sensitivity of wild-type C. elegans to the aversive odorant 1-octanol. C. elegans lacking the CAT-2 tyrosine hydroxylase enzyme, which is required for dopamine biosynthesis, are hypersensitive in their behavioral avoidance of dilute concentrations of octanol. Dopamine can also modulate the context-dependent response of C. elegans lacking RGS-3 function, a negative regulator of Gα signaling. rgs-3 mutant animals are defective in their avoidance of 100% octanol when they are assayed in the absence of food (E. coli bacterial lawn), but their response is restored when they are assayed in the presence of food or exogenous dopamine. However, it is not known which receptor might be mediating dopamine's effects on octanol avoidance. Herein we describe a role for the C. elegans D2-like receptor DOP-3 in the regulation of olfactory sensitivity. We show that DOP-3 is required for the ability of food and exogenous dopamine to rescue the octanol avoidance defect of rgs-3 mutant animals. In addition, otherwise wild-type animals lacking DOP-3 function are hypersensitive to dilute octanol, reminiscent of cat-2 mutants. Furthermore, we demonstrate that DOP-3 function in the ASH sensory neurons is sufficient to rescue the hypersensitivity of dop-3 mutant animals, while dop-3 RNAi knockdown in ASH results in octanol hypersensitivity. Taken together, our data suggest that dopaminergic signaling through DOP-3 normally acts to dampen ASH signaling and behavioral sensitivity to octanol. PMID:20209143

  2. Understanding smell--the olfactory stimulus problem.

    PubMed

    Auffarth, Benjamin

    2013-09-01

    The main problem with sensory processing is the difficulty in relating sensory input to physiological responses and perception. This is especially problematic at higher levels of processing, where complex cues elicit highly specific responses. In olfaction, this relationship is particularly obfuscated by the difficulty of characterizing stimulus statistics and perception. The core questions in olfaction are hence the so-called stimulus problem, which refers to the understanding of the stimulus, and the structure-activity and structure-odor relationships, which refer to the molecular basis of smell. It is widely accepted that the recognition of odorants by receptors is governed by the detection of physico-chemical properties and that the physical space is highly complex. Not surprisingly, ideas differ about how odor stimuli should be classified and about the very nature of information that the brain extracts from odors. Even though there are many measures for smell, there is none that accurately describes all aspects of it. Here, we summarize recent developments in the understanding of olfaction. We argue that an approach to olfactory function where information processing is emphasized could contribute to a high degree to our understanding of smell as a perceptual phenomenon emerging from neural computations. Further, we argue that combined analysis of the stimulus, biology, physiology, and behavior and perception can provide new insights into olfactory function. We hope that the reader can use this review as a competent guide and overview of research activities in olfactory physiology, psychophysics, computation, and psychology. We propose avenues for research, particularly in the systematic characterization of receptive fields and of perception.

  3. Coding of odor stimulus features among secondary olfactory structures

    PubMed Central

    Xia, Christina Z.; Adjei, Stacey

    2015-01-01

    Sensory systems must represent stimuli in manners dependent upon a wealth of factors, including stimulus intensity and duration. One way the brain might handle these complex functions is to assign the tasks throughout distributed nodes, each contributing to information processing. We sought to explore this important aspect of sensory network function in the mammalian olfactory system, wherein the intensity and duration of odor exposure are critical contributors to odor perception. This is a quintessential model for exploring processing schemes given the distribution of odor information by olfactory bulb mitral and tufted cells into several anatomically distinct secondary processing stages, including the piriform cortex (PCX) and olfactory tubercle (OT), whose unique contributions to odor coding are unresolved. We explored the coding of PCX and OT neuron responses to odor intensity and duration. We found that both structures similarly partake in representing descending intensities of odors by reduced recruitment and modulation of neurons. Additionally, while neurons in the OT adapt to odor exposure, they display reduced capacity to adapt to either repeated presentations of odor or a single prolonged odor presentation compared with neurons in the PCX. These results provide insights into manners whereby secondary olfactory structures may, at least in some cases, uniquely represent stimulus features. PMID:26041832

  4. A novel multicomponent stimulus device for use in olfactory experiments.

    PubMed

    Olsson, Shannon B; Kuebler, Linda S; Veit, Daniel; Steck, Kathrin; Schmidt, Alexandra; Knaden, Markus; Hansson, Bill S

    2011-01-30

    Olfactory studies have expanded beyond the study of single compound odor perception to explore the processing of complex mixtures and blends. The spatiotemporal presentation of blend stimuli is a challenging task requiring volatiles with diverse chemical and physical properties to be presented as a unified stimulus. This not only necessitates accurate control of the timing and homogeneity of the odor stream, but requires attention to the concentration of each blend component presented. We have developed a novel, multicomponent stimulus system for use in olfactory experiments that is capable of presenting up to 8 different odors simultaneously or in sequence at defined concentrations and time scales. Each odor is separated to minimize physical or chemical interactions, and stimulations are performed from a saturated headspace of the odor solution. Stimulus concentrations can be measured empirically or estimated using common gas laws. Photoionization detector measurements show that stimuli could be presented as cohesive blends or single components at frequencies of at least 10Hz without leakage or contamination. Solid phase microextraction measurements also show that the concentration of each component could be equilibrated through regulation of each component line's flow rate based on the different partial vapor pressures of the odorants. This device provides a unique method for introducing complex volatile mixtures for olfactory studies in a variety of animal taxa and allows for accurate control of odor intensities in both time and space.

  5. Molecular Mechanisms of Olfactory Responses to Stimulus Mixtures

    DTIC Science & Technology

    1991-02-26

    addition, the recent molecular cloning of the olfactory neuron-specific G- protein, Golf, from rat olfactory epithelium (25), has prompted a re-evaluation... molecular cloning of a G-protein that is exclusively expressed within olfactory neurons (25) prompted a re-evaluation of the molecular identities of...Fritsch, E.F. and Maniatis, T. (1989) Plasmid vectors. In Molecular Cloning : A Laboratory Manual, pp. 1.1-1.110. Cold Spring Harbor Laboratory Press, Cold

  6. The role of olfactory stimulus in adult mammalian neurogenesis.

    PubMed

    Arisi, Gabriel M; Foresti, Maira L; Mukherjee, Sanjib; Shapiro, Lee A

    2012-02-14

    Neurogenesis occurs in the adult mammalian brain in discrete regions related to olfactory sensory signaling and integration. The olfactory receptor cell population is in constant turn-over through local progenitor cells. Also, newborn neurons are added to the olfactory bulbs through a major migratory route from the subventricular zone, the rostral migratory stream. The olfactory bulbs project to different brain structures, including: piriform cortex, amygdala, entorhinal cortex, striatum and hippocampus. These structures play important roles in odor identification, feeding behavior, social interactions, reproductive behavior, behavioral reinforcement, emotional responses, learning and memory. In all of these regions neurogenesis has been described in normal and in manipulated mammalian brain. These data are reviewed in the context of a sensory-behavioral hypothesis on adult neurogenesis that olfactory input modulates neurogenesis in many different regions of the brain.

  7. Isobaric vapor-liquid equilibria of methanol + 1-octanol and ethanol + 1-octanol mixtures

    SciTech Connect

    Arce, A.; Blanco, A.; Soto, A.; Tojo, J.

    1995-07-01

    Isobaric vapor-liquid equilibrium data for methanol + 1-octanol and ethanol + 1-octanol have been measured at 101.325 kPa. The results were checked for thermodynamic consistency using Fredenslund et al.`s test, correlated using Wilson, NRTL, and UNIQUAC equations for the liquid phase activity coefficients, and compared with the predictions of the ASOG, UNIFAC, and modified UNIFAC group contribution methods.

  8. Uncoupling stimulus specificity and glomerular position in the mouse olfactory system

    PubMed Central

    Zhang, Jingji; Huang, Guangzhe; Dewan, Adam; Feinstein, Paul; Bozza, Thomas

    2012-01-01

    Sensory information is often mapped systematically in the brain with neighboring neurons responding to similar stimulus features. The olfactory system represents chemical information as spatial and temporal activity patterns across glomeruli in the olfactory bulb. However, the degree to which chemical features are mapped systematically in the glomerular array has remained controversial. Here, we test the hypothesis that the dual roles of odorant receptors, in axon guidance and odor detection, can serve as a mechanism to map olfactory inputs with respect to their function. We compared the relationship between response specificity and glomerular formation in genetically-defined olfactory sensory neurons expressing variant odorant receptors. We find that sensory neurons with the same odor response profile can be mapped to different regions of the bulb, and that neurons with different response profiles can be mapped to the same glomeruli. Our data demonstrate that the two functions of odorant receptors can be uncoupled, indicating that the mechanisms that map olfactory sensory inputs to glomeruli do so without regard to stimulus specificity. PMID:22926192

  9. The relation between stimulus and response in olfactory receptor cells of the tiger salamander.

    PubMed Central

    Firestein, S; Picco, C; Menini, A

    1993-01-01

    1. Olfactory receptor cells were isolated from the adult tiger salamander Ambystoma tigrinum and the current in response to odorant stimuli was measured with the whole-cell voltage-clamp technique while odorants at known concentrations were rapidly applied for controlled exposure times. 2. Three odorants, cineole, isoamyl acetate and acetophenone, were first applied at 5 x 10(-4) M. Out of forty-nine cells tested, 53% responded to one odorant only, 22% to two odorants and 25% to all three odorants. 3. The amplitude of the current in response to a given odorant concentration was found to be dependent on the duration of the odorant stimulus and reached a saturating peak value at 1.2 s of stimulus duration. 4. The current measured at the peak of the response for odorant steps of 1.2 s as a function of odorant concentration was well described by the Hill equation for the three odorants with Hill coefficients higher than 1 and K1/2 (odorant concentration needed to activate half the maximal current) ranging from 3 x 10(-6) to 9 x 10(-5) M. 5. It is concluded that olfactory receptor cells are broadly tuned and have a low apparent affinity for odorants, integrate stimulus information over time, and have a narrow dynamic range. PMID:8254501

  10. Liquid-liquid equilibria of water + methanol + 1-octanol and water + ethanol + 1-octanol at various temperatures

    SciTech Connect

    Arce, A.; Blanco, A.; Souza, P.; Vidal, I. . Dept. of Chemical Engineering)

    1994-04-01

    This study is part of a wider program of research on the recovery of light alcohols from dilute aqueous solutions using high molecular weight solvents. The authors report liquid-liquid equilibrium data and binodal curves for the systems water + methanol + 1-octanol and water + ethanol + 1-octanol at 25, 35, and 45 C. The data were fitted to the NRTL and UNIQUAC equations.

  11. Effect of Olfactory Stimulus on the Flight Course of a Honeybee, Apis mellifera, in a Wind Tunnel.

    PubMed

    Ikeno, Hidetoshi; Akamatsu, Tadaaki; Hasegawa, Yuji; Ai, Hiroyuki

    2013-12-31

    It is known that the honeybee, Apis mellifera, uses olfactory stimulus as important information for orienting to food sources. Several studies on olfactory-induced orientation flight have been conducted in wind tunnels and in the field. From these studies, optical sensing is used as the main information with the addition of olfactory signals and the navigational course followed by these sensory information. However, it is not clear how olfactory information is reflected in the navigation of flight. In this study, we analyzed the detailed properties of flight when oriented to an odor source in a wind tunnel. We recorded flying bees with a video camera to analyze the flight area, speed, angular velocity and trajectory. After bees were trained to be attracted to a feeder, the flight trajectories with or without the olfactory stimulus located upwind of the feeder were compared. The results showed that honeybees flew back and forth in the proximity of the odor source, and the search range corresponded approximately to the odor spread area. It was also shown that the angular velocity was different inside and outside the odor spread area, and trajectories tended to be bent or curved just outside the area.

  12. Effect of Olfactory Stimulus on the Flight Course of a Honeybee, Apis mellifera, in a Wind Tunnel

    PubMed Central

    Ikeno, Hidetoshi; Akamatsu, Tadaaki; Hasegawa, Yuji; Ai, Hiroyuki

    2013-01-01

    It is known that the honeybee, Apis mellifera, uses olfactory stimulus as important information for orienting to food sources. Several studies on olfactory-induced orientation flight have been conducted in wind tunnels and in the field. From these studies, optical sensing is used as the main information with the addition of olfactory signals and the navigational course followed by these sensory information. However, it is not clear how olfactory information is reflected in the navigation of flight. In this study, we analyzed the detailed properties of flight when oriented to an odor source in a wind tunnel. We recorded flying bees with a video camera to analyze the flight area, speed, angular velocity and trajectory. After bees were trained to be attracted to a feeder, the flight trajectories with or without the olfactory stimulus located upwind of the feeder were compared. The results showed that honeybees flew back and forth in the proximity of the odor source, and the search range corresponded approximately to the odor spread area. It was also shown that the angular velocity was different inside and outside the odor spread area, and trajectories tended to be bent or curved just outside the area. PMID:26462581

  13. A General Odorant Background Affects the Coding of Pheromone Stimulus Intermittency in Specialist Olfactory Receptor Neurones

    PubMed Central

    Rouyar, Angela; Party, Virginie; Prešern, Janez; Blejec, Andrej; Renou, Michel

    2011-01-01

    In nature the aerial trace of pheromone used by male moths to find a female appears as a train of discontinuous pulses separated by gaps among a complex odorant background constituted of plant volatiles. We investigated the effect of such background odor on behavior and coding of temporal parameters of pheromone pulse trains in the pheromone olfactory receptor neurons of Spodoptera littoralis. Effects of linalool background were tested by measuring walking behavior towards a source of pheromone. While velocity and orientation index did drop when linalool was turned on, both parameters recovered back to pre-background values after 40 s with linalool still present. Photo-ionization detector was used to characterize pulse delivery by our stimulator. The photo-ionization detector signal reached 71% of maximum amplitude at 50 ms pulses and followed the stimulus period at repetition rates up to 10 pulses/s. However, at high pulse rates the concentration of the odorant did not return to base level during inter-pulse intervals. Linalool decreased the intensity and shortened the response of receptor neurons to pulses. High contrast (>10 dB) in firing rate between pulses and inter-pulse intervals was observed for 1 and 4 pulses/s, both with and without background. Significantly more neurons followed the 4 pulses/s pattern when delivered over linalool; at the same time the information content was preserved almost to the control values. Rapid recovery of behavior shows that change of perceived intensity is more important than absolute stimulus intensity. While decreasing the response intensity, background odor preserved the temporal parameters of the specific signal. PMID:22028879

  14. Solubility of hydrogen in octane, 1-octanol, and squalane

    SciTech Connect

    Kim, K.J.; Way, T.R.; Feldman, K.T. Jr.; Razani, A.

    1997-01-01

    The solubilities of hydrogen in various liquids were measured over the pressure ranges from 690 to 1,380 kPa at a temperature of 22 C by using the modified Benson and Krause method. The liquids include octane, 1-octanol, and squalane. The solubility increases with increasing pressure and is described by Henry`s Law.

  15. Tonic and stimulus-evoked nitric oxide production in the mouse olfactory bulb

    PubMed Central

    Lowe, Graeme; Buerk, Donald G.; Ma, Jie; Gelperin, Alan

    2008-01-01

    Nitric oxide (NO) has been long assumed to play a key role in mammalian olfaction. This was based largely on circumstantial evidence, i.e. prominent staining for nitric oxide synthase (NOS) and cyclic GMP or soluble guanylyl cyclase, an effector enzyme activated by NO, in local interneurons of the olfactory bulb. Here we employ innovative custom-fabricated NO micro-sensors to obtain the first direct, time-resolved measurements of NO signaling in the olfactory bulb. In 400 μm thick mouse olfactory bulb slices, we detected a steady average basal level of 87 nM NO in the extracellular space of mitral or granule cell layers. This NO ‘tone’ was sensitive to NOS substrate manipulation (200 μM L-arginine, 2 mM L-NAME) and Mg2+ modulation of NMDA receptor conductance. Electrical stimulation of olfactory nerve fibers evoked transient (peak at 10 s) increments in NO levels 90 – 100 nM above baseline. In the anesthetized mouse, NO micro-sensors inserted into the granule cell layer detected NO transients averaging 55 nM in amplitude and peaking at 3.4 sec after onset of a 5 sec odorant stimulation. These findings suggest dual roles for NO signaling in the olfactory bulb – tonic inhibitory control of principal neurons, and regulation of circuit dynamics during odor information processing. PMID:18407420

  16. Cholinergic Modulation during Acquisition of Olfactory Fear Conditioning Alters Learning and Stimulus Generalization in Mice

    ERIC Educational Resources Information Center

    Pavesi, Eloisa; Gooch, Allison; Lee, Elizabeth; Fletcher, Max L.

    2013-01-01

    We investigated the role of cholinergic neurotransmission in olfactory fear learning. Mice receiving pairings of odor and foot shock displayed fear to the trained odor the following day. Pretraining injections of the nicotinic antagonist mecamylamine had no effect on subsequent freezing, while the muscarinic antagonist scopolamine significantly…

  17. Neurogenesis Drives Stimulus Decorrelation in a Model of the Olfactory Bulb

    PubMed Central

    Chow, Siu-Fai; Wick, Stuart D.; Riecke, Hermann

    2012-01-01

    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. PMID:22442645

  18. Solubility of pyrene in binary alkane + 1-octanol solvent mixtures

    SciTech Connect

    Zvaigzne, A.I.; Acree, W.E. Jr.

    1995-09-01

    Solid-liquid equilibrium data of organic nonelectrolyte systems are becoming increasingly important in the petroleum industry, particularly in light of present trends toward heavier feedstocks and known carcinogenicity/mutagenicity of many of the larger polycyclic aromatic compounds. Experimental solubilities are reported for pyrene dissolved in seven binary mixtures containing 1-octanol with hexane, heptane, octane, cyclohexane, methylcyclohexane, 2,2,4-trimethylpentane, and (1,1-dimethylethyl)cyclohexane at 26 C. Results of these measurements are used to test two mathematical representations based upon the combined nearly ideal binary solvent (NIBS)/Redlich-Kister equation and modified Wilson model. For the system studied, the three-parameter combined NIBS/Redlich-Kister equation was found to provide the better mathematical representation, with deviations between experimental and back-calculated values being on the order of {+-}1.5% or lees. Slightly larger deviations were noted in the case of the two-parameter modified Wilson equation.

  19. Brain activation by an olfactory stimulus paired with juvenile play in female rats.

    PubMed

    Paredes-Ramos, P; McCarthy, M M; Bowers, J M; Miquel, M; Manzo, J; Coria-Avila, G A

    2014-06-22

    We have previously shown that reward experienced during social play at juvenile age can be paired with artificial odors, and later in adulthood facilitate olfactory conditioned partner preferences (PP) in female rats. Herein, we examined the expression of FOS immunoreactivity (FOS-IR) following exposure to the odor paired with juvenile play (CS+). Starting at day P31 females received daily 30-min periods of social play with lemon-scented (paired group) or unscented females (unpaired group). At day P42, they were tested for play-PP with two juvenile males, one bearing the CS+ (lemon) and one bearing a novel odor (almond). Females were ovariectomized, hormone-primed and at day P55 tested for sexual-PP between two adult stud males scented with lemon or almond. In both tests, females from the paired group displayed conditioned PP (play or sexual) toward males bearing the CS+. In the present experiments females were exposed at day P59 to the CS+ during 60 min and their brains processed for FOS-IR. One group of female rats (Play+Sex) underwent play-PP and sexual-PP, whereas a second group of females (Play-only) underwent exclusively play-PP but not sexual-PP. Results showed that in the Play-only experiment exposure to the CS+ induced more FOS-IR in the medial prefrontal cortex, orbitofrontal cortex, dorsal striatum, and ventral tegmental area as compared to females from the unpaired group. In the Play+Sex experiment, more FOS-IR was observed in the piriform cortex, dorsal striatum, lateral septum, nucleus accumbens shell, bed nucleus of the stria terminalis and medial amygdala as compared to females from the unpaired group. Taken together, these results indicate mesocorticolimbic brain areas direct the expectation and/or choice of conditioned partners in female rats. In addition, transferring the meaning of play to sex preference requires different brain areas.

  20. Estimation of solubility of organic compounds in 1-octanol

    SciTech Connect

    Li, A.; Pinsuwan, S.; Yalkowsky, S.H.

    1994-12-31

    Five methods were evaluated for their ability to estimate the solubility of organic compounds in 1-octanol. OCTASOL is a modified group contribution method developed in this study. Another proposed method uses the product of octanol-water partition coefficient (K{sub ow}) and water solubility (S{sub w}) as the approximate of octanol solubility. The average absolute error of the estimate obtained from using OCTASOL is 0.25 log units for the training set (N = 180), and 0.29 log units for a test set (N = 10). When the K{sub ow}*S{sub w} method is used, the error is 0.29 log units (N = 124). Three other approaches (ideal solubility, regular solution theory, and UNIFAC) are also evaluated. Their average absolute errors are 0.85 (N = 209), 0.58 (N = 174), and 0.31 (N = 1 31) log units, respectively. The difference between ideal solubility and octanol solubility increases as the latter decreases. Regular solution theory, combined with Fedors` group contribution method to estimate solubility parameter of solutes, compensates significantly for the systematic errors resulted from using the ideal solubility. Lack of the needed group interaction parameters prevents application of UNIFAC to about 50 compounds in the data set used in this study.

  1. Densities, refractive indices, and excess molar volumes of the ternary systems water + methanol + 1-octanol and water + ethanol + 1-octanol and their binary mixtures at 298. 15 K

    SciTech Connect

    Arce, A.; Blanco, A.; Soto, A.; Vidal, I. )

    1993-04-01

    The densities, refractive indices, and excess molar volumes of the ternary systems water + methanol + 1-octanol and water + ethanol + 1-octanol have been determined at 298.15 K. These physical properties are easily measured, and the authors' tabulated data thus allow indirect determination of the composition of arbitrary mixtures. The authors have found no directly comparable data in the literature, though data are available for the binary mixtures formed by these components and for other ternary mixtures containing these binary systems. The excess volumes have been correlated using Redlich-Kister functions.

  2. Microbial production of 1-octanol: A naturally excreted biofuel with diesel-like properties

    PubMed Central

    Akhtar, M. Kalim; Dandapani, Hariharan; Thiel, Kati; Jones, Patrik R.

    2014-01-01

    The development of sustainable, bio-based technologies to convert solar energy and carbon dioxide into fuels is a grand challenge. A core part of this challenge is to produce a fuel that is compatible with the existing transportation infrastructure. This task is further compounded by the commercial desire to separate the fuel from the biotechnological host. Based on its fuel characteristics, 1-octanol was identified as an attractive metabolic target with diesel-like properties. We therefore engineered a synthetic pathway specifically for the biosynthesis of 1-octanol in Escherichia coli BL21(DE3) by over-expression of three enzymes (thioesterase, carboxylic acid reductase and aldehyde reductase) and one maturation factor (phosphopantetheinyl transferase). Induction of this pathway in a shake flask resulted in 4.4 mg 1-octanol L−1 h−1 which exceeded the productivity of previously engineered strains. Furthermore, the majority (73%) of the fatty alcohol was localised within the media without the addition of detergent or solvent overlay. The deletion of acrA reduced the production and excretion of 1-octanol by 3-fold relative to the wild-type, suggesting that the AcrAB–TolC complex may be responsible for the majority of product efflux. This study presents 1-octanol as a potential fuel target that can be synthesised and naturally accumulated within the media using engineered microbes. PMID:27066394

  3. Surface tension of aqueous lithium bromide solutions containing 1-octanol as a heat-transfer additive

    SciTech Connect

    Ishida, Kenji; Mori, Y.H.

    1996-11-01

    The surface tension of simulated heat-pump working fluids, aqueous solutions of lithium bromide containing 1-octanol, has been measured, for the first time using a recently developed technique (Ishida et al., Rev. Sci. Instrum. 64, 1,324 (1993)) which is inherently suitable for characterizing the surfactant solution surfaces from the aspects of thermodynamic adsorption equilibrium and adsorption kinetics. The measurement has revealed that even the highest-grade reagents of lithium bromide commercially available are not necessarily free from surfactant impurities. Obtained data on the surface tension vs 1-octanol concentration have been examined on the basis of an equilibrium adsorption model. Through the optimal fitting of the Langmuir-type surface equation of state to the data, they have calculated the surface tension vs surface excess relation and also the variation in surface tension vs 1-octanol concentration relation with the surface area per unit volume of a given solution.

  4. Preparation and characterization of magnetorheological fluids by dispersion of carbonyl iron microparticles in PAO/1-octanol

    NASA Astrophysics Data System (ADS)

    Morillas, Jose R.; Bombard, Antonio J. F.; de Vicente, Juan

    2016-01-01

    This work reports an investigation into the effect of 1-octanol concentration in the formulation of concentrated polyalphaolefin-based magnetorheological fluids. Special emphasis is paid to the understanding of their kinetic stability and redispersibility characteristics in the ‘off-state’ (absence of magnetic field). Techniques employed involve light scattering, electroacoustics and rheometry, using a vane tool, to precisely determine the yield value. The results obtained show a minimum in the rheological material functions for 1-octanol concentrations within the range 0.5-5.0 wt%. This finding is tentatively explained in terms of the potential energy of interaction between the dispersed particles as a result of the formation of 1-octanol micelles in good agreement with Bombard and Dukhin (2014 Langmuir 30 4517-21).

  5. Phase volume changes accompanying water extraction from aqueous electrolyte solutions by 1-octanol

    SciTech Connect

    Sun, Y.; Moyer, B.A.

    1995-03-01

    The extraction of water by 1-octanol was calculated as a function of aqueous electrolyte concentration and initial O/A volume ratio for a series of representative salts, including LiCl, NaCl, KCl, NaNO{sub 3}, NaClO{sub 4}, MgCl{sub 2}, and CaCl{sub 2}. These results were then used to calculate the resultant phase-volume changes and aqueous-electrolyte-concentration changes. Such corrections are necessitated for precise extraction measurements employing 1-octanol as a diluent, especially as the O/A phase ratio exceeds unity. 20 refs., 2 figs., 1 tab.

  6. Direct calculation of 1-octanol-water partition coefficients from adaptive biasing force molecular dynamics simulations.

    PubMed

    Bhatnagar, Navendu; Kamath, Ganesh; Chelst, Issac; Potoff, Jeffrey J

    2012-07-07

    The 1-octanol-water partition coefficient log K(ow) of a solute is a key parameter used in the prediction of a wide variety of complex phenomena such as drug availability and bioaccumulation potential of trace contaminants. In this work, adaptive biasing force molecular dynamics simulations are used to determine absolute free energies of hydration, solvation, and 1-octanol-water partition coefficients for n-alkanes from methane to octane. Two approaches are evaluated; the direct transfer of the solute from 1-octanol to water phase, and separate transfers of the solute from the water or 1-octanol phase to vacuum, with both methods yielding statistically indistinguishable results. Calculations performed with the TIP4P and SPC∕E water models and the TraPPE united-atom force field for n-alkanes show that the choice of water model has a negligible effect on predicted free energies of transfer and partition coefficients for n-alkanes. A comparison of calculations using wet and dry octanol phases shows that the predictions for log K(ow) using wet octanol are 0.2-0.4 log units lower than for dry octanol, although this is within the statistical uncertainty of the calculation.

  7. Liquefaction of sawdust in 1-octanol using acidic ionic liquids as catalyst.

    PubMed

    Lu, Zexiang; Zheng, Huaiyu; Fan, Liwei; Liao, Yiqiang; Ding, Bingjing; Huang, Biao

    2013-08-01

    Acidic ionic liquids (AILs) as a novel catalyst in biomass liquefaction can accord with the demand of green chemistry and enhance the development of biomass thermal chemical conversion. A series of AILs containing HSO4- were synthesized by the imidazolium cation functionalization and applied to the Chinese fir sawdust liquefaction in 1-octanol in this paper. The experimental results showed that the liquefaction rate was gradually improved with the AILs acidity increasing, and reached 71.5% when 1-(4-sulfobutyl)-3-methylmidazolium hydrosulfate was used as catalyst with the 6:1 mass ratio of 1-octanol to sawdust at 423K after 60 min. Lignin, hemicellulose and cellulose were orderly desquamated, and then depolymerized and liquefied with the catalyst acidity increasing in the sawdust liquefaction process. The light oil was mainly composed of the octyl ether and the octyl ester compounds, suggesting that the solvent may play an important role in producing the high octane rating biofuel.

  8. Phase transitions of n-hexadecane in nanoencapsulated binary solutions of n-hexadecane and 1-octanol.

    PubMed

    Tubbs, Kyle W; Nguyen, Vincent T; Adalsteinsson, Thorsteinn

    2012-04-05

    Binary solutions of n-hexadecane and 1-octanol were encapsulated within poly(tert-butyl methacrylate) nanocapsules and the phase transition behavior of the n-hexadecane studied. A sigmoidal correlation was found between the binary composition of the encapsulated oil and the oil formulation prior to encapsulation. At low 1-octanol fractions in the synthesis, almost no alcohol was encapsulated, but at high 1-octanol fractions, the capsules were enriched in alcohol. The freezing point of the encapsulated n-hexadecane was considerably lower than in the bulk phase. This freezing point was further reduced as the radius of the particle was reduced, which is expected from the Gibbs-Thompson equation. The extracted value at infinite radii was, however, 14 °C below the bulk freezing point. The colligative effect of 1-octanol on the freezing point of n-hexadecane, i.e., dT(f)/dx(m), where x(m) is the mass fraction of 1-octanol, was nearly identical to that measured in the bulk system. The specific enthalpy of freezing for the encapsulated system was considerably different from the bulk system. In the bulk system, the freezing enthalpy for n-hexadecane was nearly constant up to 60% mass of 1-octanol. The freezing enthalpy for the encapsulated n-hexadecane showed greater variation with % mass 1-octanol, and had a considerably lower absolute value than the bulk system.

  9. Excess Gibbs free energies at several temperatures of butanone with 1-hexanol or 1-octanol

    SciTech Connect

    Garriga, R.; Sanchez, F.; Perez, P.; Gracia, M.

    1996-09-01

    Vapor pressures of butanone + 1-hexanol or 1-octanol, at several temperatures between 288.15 K and 323.15 K, were measured by a static method. Activity coefficients and excess molar Gibbs free energies G{sup E} were calculated by Barker`s method. Reduction of the vapor pressure data is carried out by means of the Redlich-Kister and Wilson correlations.

  10. The effect of cholesterol on the partitioning of 1-octanol into POPC vesicles

    NASA Astrophysics Data System (ADS)

    Zakariaee Kouchaksaraee, Roja

    Microcalorimetry has become a method of choice for sensitive characterization of biomolecular interactions. In this study, isothermal titration calorimetry (ITC) was used to measure the partitioning of 1-octanol into lipid bilayers composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), a semi-unsaturated lipid, and cholesterol, a steroid, as a function of cholesterol molar concentration. The ITC instrument measures the heat evolved or absorbed upon titration of a liposome dispersion, at concentrations ranging from 0 to 40% cholesterol, into a suspension of 1-octanol in water. A model function was fit to the data in order to determine the partition coefficient of octanol into POPC bilayers and the enthalpy of interaction. I found that the partition coefficient increases and the heat of interaction becomes less negative with increasing cholesterol content, in contrast to results found by other groups for partitioning of alcohols into lipid-cholesterol bilayers containing saturated lipids. The heat of dilution of vesicles was also measured. Keywords: Partition coefficient; POPC; 1-Octanol; Cholesterol; Isothermal titration calorimetry; Lipid-alcohol interactions. Subject Terms: Calorimetry; Membranes (Biology); Biophysics; Biology -- Technique; Bilayer lipid membranes -- Biotechnology; Lipid membranes -- Biotechnology.

  11. Salting-out phenomenon and 1-octanol/water partition coefficient of metalaxyl pesticide.

    PubMed

    Saab, J; Bassil, G; Abou Naccoul, R; Stephan, J; Mokbel, I; Jose, J

    2011-02-01

    In this paper, we present the effect of inorganic cations such as Na+, K+, Ca2+, Mg2+ on the salting-out phenomenon of metalaxyl from pure water to aqueous salt solutions. Moreover the 1-octanol/water partition coefficient in pure water is presented. To accomplish this, aqueous solubility of metalaxyl was determined in pure water, in different salt solution (NaCl, KCl, CaCl2 and MgCl2), and at different concentration level ranging from 0.01 to 1.5 M. The 1-octanol/water partition coefficient was determined using the static shake-flask method. Solubility was determined using dynamic saturation method for pure water in the range of 298.15-325.15 K and at 298.15 K for different salt solutions. The solubility value in pure water for studied interval was found constant (m=3.118×10(-2) mol kg(-1)). Solubility values were used to calculate the standard molar Gibbs free energy of dissolution (ΔsolG°) and transfer (ΔtrG°) at 298.15 K. The values of ΔtrG° from pure to all studied aqueous salt solutions did not exceed 2 kJ mol(-1), the value of ΔsolG° of dissolution is 18.5 ±0.72 kJ mol(-1). The 1-octanol/water partition coefficient in pure water log Ko/w is equal to 1.69. The obtained results confirm the classification of the neutral metalaxyl as a slightly hydrophobic molecule.

  12. Density and viscosity for monoethanolamine + 1-propanol, + 1-hexanol, and + 1-octanol

    SciTech Connect

    Lee, M.J.; Lin, T.K.; Pai, Y.H.; Lin, K.S.

    1997-09-01

    Monoethanolamine (MEA) is a feasible agent for removing carbon dioxide and hydrogen sulfide from sour gases. Densities and viscosities were measured for monoethanolamine (MEA) + 1-propanol, MEA + 1-hexanol, and MEA + 1-octanol at 303.15 K, 313.15 K, and 323.15 K. The excess volumes and viscosity deviations from the mole fraction average were calculated and correlated by a Redlich-Kister type equation. McAllister`s three-body interaction model was also applied to correlate the kinematic viscosities.

  13. Comparison of hydrogen bonding in 1-octanol and 2-octanol as probed by spectroscopic techniques.

    PubMed

    Palombo, Francesca; Sassi, Paola; Paolantoni, Marco; Morresi, Assunta; Cataliotti, Rosario Sergio

    2006-09-14

    Liquid 1-octanol and 2-octanol have been investigated by infrared (IR), Raman, and Brillouin experiments in the 10-90 degrees C temperature range. Self-association properties of the neat liquids are described in terms of a three-state model in which OH oscillators differently implicated in the formation of H-bonds are considered. The results are in quantitative agreement with recent computational studies for 1-octanol. The H-bond probability is obtained by Raman data, and a stochastic model of H-bonded chains gives a consistent picture of the self-association characteristics. Average values of hydrogen bond enthalpy and entropy are evaluated. The H-bond formation enthalpy is ca. -22 kJ/mol and is slightly dependent on the structural isomerism. The different degree of self-association for the two octanols is attributed to entropic factors. The more shielded 2-isomer forms larger fractions of smaller, less cooperative, and more ordered clusters, likely corresponding to cyclic structures. Signatures of a different cluster organization are also evidenced by comparing the H-bond energy dispersion (HBED) of OH stretching IR bands. A limiting cooperative H-bond enthalpy value of 27 kJ/mol is found. It is also proposed that the different H-bonding capabilities may modulate the extent of interaggregate hydrocarbon interactions, which is important in explaining the differences in molar volume, compressibility, and vaporization enthalpy for the two isomers.

  14. 1-Octanol, a self-inhibitor of spore germination in Penicillium camemberti.

    PubMed

    Gillot, Guillaume; Decourcelle, Nicolas; Dauer, Gaëlle; Barbier, Georges; Coton, Emmanuel; Delmail, David; Mounier, Jérôme

    2016-08-01

    Penicillium camemberti is a technologically relevant fungus used to manufacture mold-ripened cheeses. This fungal species produces many volatile organic compounds (VOCs) including ammonia, methyl-ketones, alcohols and esters. Although it is now well known that VOCs can act as signaling molecules, nothing is known about their involvement in P. camemberti lifecycle. In this study, spore germination was shown to be self-regulated by quorum sensing in P. camemberti. This phenomenon, also called "crowding effect", is population-dependent (i.e. observed at high population densities). After determining the volatile nature of the compounds involved in this process, 1-octanol was identified as the main compound produced at high-spore density using GC-MS. Its inhibitory effect was confirmed in vitro and 3 mM 1-octanol totally inhibited spore germination while 100 μM only transiently inhibited spore germination. This is the first time that self-inhibition of spore germination is demonstrated in P. camemberti. The obtained results provide interesting perspectives for better control of mold-ripened cheese processes.

  15. Solvation of decane and benzene in mixtures of 1-octanol and N, N-dimethylformamide

    NASA Astrophysics Data System (ADS)

    Kustov, A. V.; Smirnova, N. L.

    2016-09-01

    The heats of dissolution of decane and benzene in a model system of octanol-1 (OctOH) and N, N-dimethylformamide (DMF) at 308 K are measured using a variable temperature calorimeter equipped with an isothermal shell. Standard enthalpies are determined and standard heat capacities of dissolution in the temperature range of 298-318 K are calculated using data obtained in [1, 2]. The state of hydrocarbon molecules in a binary mixture is studied in terms of the enhanced coordination model (ECM). Benzene is shown to be preferentially solvated by DMF over the range of physiological temperatures. The solvation shell of decane is found to be strongly enriched with 1-octanol. It is obvious that although both hydrocarbons are nonpolar, the presence of the aromatic π-system in benzene leads to drastic differences in their solvation in a lipid-protein medium.

  16. Preferable solvatation of decane and benzene in 1-octanol- N, N-dimethylformamide mixed solvent

    NASA Astrophysics Data System (ADS)

    Kustov, A. V.; Smirnova, N. L.; Berezin, M. B.

    2014-01-01

    Heat effects of the dissolution of decane and benzene in a model system of 1-octanol (OctOH)- N, N-dimethylformamide are measured at 298 and 318 K using a variable temperature calorimeter with an isotermic shell. The state of hydrocarbon molecules in the mixed solvent is studied using an extended coordination model and is compared to earlier data for ethyl acetate (EtOAc), DMF, OctOH, and tetramethyl hematoporphyrin (TMHP). It is shown that the polar carboxylic groups of porphyrin are preferably solvated by amide molecules due to stronger interaction with DMF, while nonpolar aliphatic groups are solvated by alcohol molecules. We conclude that a solvate shell of aromatic benzene is strongly enriched with DMF over the range of compositions, suggesting that the weakening of the preferable solvatation of porphyrin relative to EtOAc is due primarily to the influence of nonpolar substituents.

  17. Thermodynamic and structural description of europium complexation in 1-octanol solution

    SciTech Connect

    Charbonnel, M.C.; Vu, T.H.; Boubals, N.; Couston, L.

    2008-07-01

    Polydentate N-bearing ligands such as bis-triazinyl-pyridines (BTPS) are interesting extractants for actinide(III)/lanthanide(III) separation. A description of europium complexation in 1-octanol solutions was undertaken to enhance the knowledge of the extraction mechanisms. Time- Resolved Laser-Induced Fluorescence (TRLIF) spectroscopy allows determination of the first solvation shell for europium(III) nitrate, chloride, and perchlorate with different amounts of water. Europium nitrate complexation by iPr-BTP was then studied by TRLIF and microcalorimetry; the stability constant related to the formation of Eu(BTP){sub 3}{sup 3+} is similar by both techniques (log {beta}{sub 3} = 11.3 {+-} 0.5). The difference of solvation of the cation seems to have an influence on the thermodynamic properties related to the complexation with organic ligands. (authors)

  18. 1-Octanol/Water Partition Coefficients of n-Alkanes from Molecular Simulations of Absolute Solvation Free Energies.

    PubMed

    Garrido, Nuno M; Queimada, António J; Jorge, Miguel; Macedo, Eugénia A; Economou, Ioannis G

    2009-09-08

    The 1-octanol/water partition coefficient is an important thermodynamic variable usually employed to understand and quantify the partitioning of solutes between aqueous and organic phases. It finds widespread use in many empirical correlations to evaluate the environmental fate of pollutants as well as in the design of pharmaceuticals. The experimental evaluation of 1-octanol/water partition coefficients is an expensive and time-consuming procedure, and thus, theoretical estimation methods are needed, particularly when a physical sample of the solute may not yet be available, such as in pharmaceutical screening. 1-Octanol/water partition coefficients can be obtained from Gibbs free energies of solvation of the solute in both the aqueous and the octanol phases. The accurate evaluation of free energy differences remains today a challenging problem in computational chemistry. In order to study the absolute solvation Gibbs free energies in 1-octanol, a solvent that can mimic many properties of important biological systems, free energy calculations for n-alkanes in the range C1-C8 were performed using molecular simulation techniques, following the thermodynamic integration approach. In the first part of this paper, we test different force fields by evaluating their performance in reproducing pure 1-octanol properties. It is concluded that all-atom force fields can provide good accuracy but at the cost of a higher computational time compared to that of the united-atom force fields. Recent versions of united-atom force fields, such as Gromos and TraPPE, provide satisfactory results and are, thus, useful alternatives to the more expensive all-atom models. In the second part of the paper, the Gibbs free energy of solvation in 1-octanol is calculated for several n-alkanes using three force fields to describe the solutes, namely Gromos, TraPPE, and OPLS-AA. Generally, the results obtained are in excellent agreement with the available experimental data and are of similar

  19. pKa and solubility of drugs in water, ethanol, and 1-octanol.

    PubMed

    Domańska, Urszula; Pobudkowska, Aneta; Pelczarska, Aleksandra; Gierycz, Paweł

    2009-07-02

    Dissociation constants and corresponding pK(a) values of five drugs were obtained with the Bates-Schwarzenbach method using a Perkin-Elmer Lambda 35 UV/vis spectrophotometer at temperature 298.15 K in the buffer solutions. Atropine, promethazine hydrochloride, ibuprofen, flurbiprofen, and meclofenamic acid sodium salt exhibited pK(a) values of 10.3, 6.47, 5.38, 4.50, and 4.39, respectively. The equilibrium mole fraction solubilities of six drugs were measured in a range of temperatures from 240 to 340 K in three important solvents for drugs: water, ethanol, and 1-octanol using the dynamic method. The basic thermal properties of pure drugs, i.e., melting and glass-transition temperatures, as well as the enthalpy of melting and the molar heat capacity at glass transition (at constant pressure) have been measured with the differential scanning microcalorimetry technique (DSC). Molar volumes have been calculated with the Barton group contribution method. The experimental solubility data have been correlated by means of three commonly known G(E) equations: the Wilson, NRTL, and UNIQUAC, with the assumption that the systems studied here have revealed simple eutectic mixtures. As a measure of goodness of correlation, the root-mean-square deviations of temperature have been used. The activity coefficients of the drugs in saturated solutions for each correlated binary mixture were calculated from the experimental data.

  20. [FTIR analysis of products derived from wood liquefaction with 1-octanol].

    PubMed

    Zou, Xian-Wu; Yang, Zhi; Qin, Te-Fu

    2009-06-01

    Solvolysis is one of the important processes of biomass liquefaction. To produce superior quality liquid biofuel from biomass under mild conditions, it is essential to exploit novel reactive liquid solvent. Furthermore, the evaluation of liquefaction efficiency is carried out mainly by the means of analysis of the products derived from biomass liquefaction. In the present study, liquefaction of poplar wood powder in acidified 1-octanol was investigated with a stainless steel autoclave. Residue, heavy oil and light oil were separated from the liquefaction products by extraction with acetone and n-hexane successively. FTIR analysis was carried out on these liquefaction compositions to illuminate the liquefaction regularities and mechanisms of cellulose, hemicellulose and lignin of wood. The results showed that liquefaction oils were complex mixture containing hydroxide, carbonyl, methoxyl, aromatic and aether. Liquefactions of cellulose and hemicellulose were easier than that of lignin. Cellulose and hemicellulose were converted to light oil, however, lignin was mainly converted to heavy oil. At 150 degrees C, lignin was depolymerized and degraded into micromolecular aromatic compounds, among which condensation reactions took place when reaction temperature increased.

  1. Kinetics of the extraction of succinic acid with tri-n-octylamine in 1-octanol solution.

    PubMed

    Jun, Young-Si; Huh, Yun Suk; Hong, Won Hi; Hong, Yeon Ki

    2005-01-01

    Kinetic studies for the extraction of succinic acid from aqueous solution with 1-octanol solutions of tri-n-octylamine (TOA) were carried out using a stirred cell with a microporous hydrophobic membrane. The interfacial concentrations of species were correlated and thus the intrinsic kinetics was obtained. The overall extraction process was controlled by the chemical reaction at or near the interface between the aqueous and organic phases. The formation reaction of succinic acid-TOA complex was found to be first order with respect to the concentration of succinic acid in the aqueous phase and the order of 0.5 with respect to that of TOA in the organic phase with a rate constant of (3.14 +/- 0.6) x 10(-8) m(2.5) x mol(-0.5) x s(-1). The dissociation reaction of succinic acid-TOA complex was found to be the second-order with respect to that of succinic acid-TOA complex in the organic phase and the order of -2 with respect to that of TOA in the organic phase with a rate constant of (1.44 +/- 1.4) x 10(-4) mol x m(-2) x s(-1).

  2. Equilibria and speciation in the solvent extraction of lithium chloride by nonamethyl-14-crown-4 ether in 1-octanol

    SciTech Connect

    Sun, Y.; Chen, Z.; Cavenaugh, K.L.; Sachleben, R.A.; Moyer, B.A.

    1996-05-30

    The equilibria and speciation in the solvent extraction of LiCl by nonamethyl-14-crown-4 ether in 1-octanol have been determined by use of ion chromatography (IC) and inductively coupled plasma (ICP) analyses, equilibrium modeling with the program SXLSQI, and {sup 7}Li NMR measurements. SXLSQI modeling of the extraction data indicates the formation of a 1:1 metal:crown complex in the organic phase. The complex apparently exists as an ion-pair Li(crown)Cl, which partially dissociates to the complex cation Li(crown){sup +} and free chloride anion Cl{sup -}. Extraction of LiCl by 1-octanol to give the organic-phase ion-pair LiCl and its dissociated ions Li{sup +} and Cl{sup -} must be included in the data analysis. {sup 7}Li NMR measurements verify the existence of free and crown-complexed lithium species in 1-octanol, and the measurements quantitatively agree with results from the SXLSQI model. 41 refs., 4 figs., 2 tabs.

  3. A Comparison of the Microbial Production and Combustion Characteristics of Three Alcohol Biofuels: Ethanol, 1-Butanol, and 1-Octanol.

    PubMed

    Kremer, Florian; Blank, Lars M; Jones, Patrik R; Akhtar, M Kalim

    2015-01-01

    Over the last decade, microbes have been engineered for the manufacture of a variety of biofuels. Saturated linear-chain alcohols have great potential as transport biofuels. Their hydrocarbon backbones, as well as oxygenated content, confer combustive properties that make it suitable for use in internal combustion engines. Herein, we compared the microbial production and combustion characteristics of ethanol, 1-butanol, and 1-octanol. In terms of productivity and efficiency, current microbial platforms favor the production of ethanol. From a combustion standpoint, the most suitable fuel for spark-ignition engines would be ethanol, while for compression-ignition engines it would be 1-octanol. However, any general conclusions drawn at this stage regarding the most superior biofuel would be premature, as there are still many areas that need to be addressed, such as large-scale purification and pipeline compatibility. So far, the difficulties in developing and optimizing microbial platforms for fuel production, particularly for newer fuel candidates, stem from our poor understanding of the myriad biological factors underpinning them. A great deal of attention therefore needs to be given to the fundamental mechanisms that govern biological processes. Additionally, research needs to be undertaken across a wide range of disciplines to overcome issues of sustainability and commercial viability.

  4. A Comparison of the Microbial Production and Combustion Characteristics of Three Alcohol Biofuels: Ethanol, 1-Butanol, and 1-Octanol

    PubMed Central

    Kremer, Florian; Blank, Lars M.; Jones, Patrik R.; Akhtar, M. Kalim

    2015-01-01

    Over the last decade, microbes have been engineered for the manufacture of a variety of biofuels. Saturated linear-chain alcohols have great potential as transport biofuels. Their hydrocarbon backbones, as well as oxygenated content, confer combustive properties that make it suitable for use in internal combustion engines. Herein, we compared the microbial production and combustion characteristics of ethanol, 1-butanol, and 1-octanol. In terms of productivity and efficiency, current microbial platforms favor the production of ethanol. From a combustion standpoint, the most suitable fuel for spark-ignition engines would be ethanol, while for compression-ignition engines it would be 1-octanol. However, any general conclusions drawn at this stage regarding the most superior biofuel would be premature, as there are still many areas that need to be addressed, such as large-scale purification and pipeline compatibility. So far, the difficulties in developing and optimizing microbial platforms for fuel production, particularly for newer fuel candidates, stem from our poor understanding of the myriad biological factors underpinning them. A great deal of attention therefore needs to be given to the fundamental mechanisms that govern biological processes. Additionally, research needs to be undertaken across a wide range of disciplines to overcome issues of sustainability and commercial viability. PMID:26301219

  5. Photocatalytic degradation of 1-octanol on anchored titanium oxide and on TiO{sub 2} powder catalysts

    SciTech Connect

    Yamashita, Hiromi; Ichihashi, Yuichi; Harada, Masaru

    1996-01-01

    The liquid-phase photocatalytic oxidative degradation of 1-octanol in oxygenated acetonitrile on highly dispersed titanium oxide catalysts anchored onto transparent Vycor glass was compared with that obtained on standard TiO{sup 2} powder. The anchored photocatalysts were prepared through the facile reaction between surface OH groups of Vycor glass and TiCl{sub 4}. UV irradiation of the anchored catalyst at room temperature led to the photocatalytic degradation of 1-octanol and the production of 1-octanal as the major product. The large surface area of the photocatalyst was one of the most important factors in achieving a high efficiency in the liquid-phase photocatalytic reaction. The specific photocatalytic activity per unit weight of titanium oxide of the highly dispersed anchored catalyst was much higher than that for the TiO{sub 2} powder because of the high activity of the charge transfer complex (Ti{sup 3+}-O{sup -}){sup *}. Furthermore, the filtration of the anchored photocatalysts from the liquid reactants was much easier than that of the small particles of TiO{sub 2} powder. 21 refs., 7 figs., 1 tab.

  6. Determination of infinite dilution activity coefficients and 1-octanol/water partition coefficients of volatile organic pollutants

    SciTech Connect

    Tse, G.; Sandler, S.I. . Dept. of Chemical Engineering)

    1994-04-01

    The characterization of pollutants is of growing interest as concerns about the environment increase. One parameter useful in predicting the fate of a chemical in the environment, the infinite dilution activity coefficient, has been determined here for several EPA priority pollutants in 1-octanol at 25 C using a relative gas-liquid chromatographic measurement technique. A simple correlation has been developed relating the limiting activity coefficients of a species in pure water and in pure 1-octanol to its octanol/water partition coefficient. Agreement between the experimental results and published values is very good. The method developed here of computing the octanol/water partition coefficient from gas chromatographic measurements of its infinite dilution activity coefficients is an improvement over traditional partition coefficient determination methods in that it is easier and quicker, without a loss of accuracy. Furthermore, the authors show that this method is applicable to chemicals covering a large range of hydrophobicities (1.0 < log K[sub OW] < 5.0).

  7. Developmental regulation of the effects of fibroblast growth factor-2 and 1-octanol on neuronogenesis: implications for a hypothesis relating to mitogen-antimitogen opposition

    NASA Technical Reports Server (NTRS)

    Goto, T.; Takahashi, T.; Miyama, S.; Nowakowski, R. S.; Bhide, P. G.; Caviness, V. S. Jr

    2002-01-01

    Neocortical neurons arise from a pseudostratified ventricular epithelium (PVE) that lies within the ventricular zone (VZ) at the margins of the embryonic cerebral ventricles. We examined the effects of fibroblast growth factor-2 (FGF-2) and 1-octanol on cell output behavior of the PVE in explants of the embryonic mouse cerebral wall. FGF-2 is mitogenic and 1-octanol antimitogenic in the PVE. Whereas all postmitotic cells migrate out of the VZ in vivo, in the explants some postmitotic cells remain within the VZ. We refer to these cells as the indeterminate or I fraction, because they neither exit from the VZ nor reenter S phase as part of the proliferative (P) fraction. They are considered to be either in an extremely prolonged G(1) phase, unable to pass the G(1)/S transition, or in the G(0) state. The I fate choice is modulated by both FGF-2 and 1-octanol. FGF-2 decreased the I fraction and increased the P fraction. In contrast, 1-octanol increased the I fraction and nearly eliminated the P fraction. The effects of FGF-2 and 1-octanol were developmentally regulated, in that they were observed in the developmentally advanced lateral region of the cerebral wall but not in the medial region. Copyright 2002 Wiley-Liss, Inc.

  8. Olfactory illusions: where are they?

    PubMed

    Stevenson, Richard J

    2011-12-01

    It has been suggested that there maybe no olfactory illusions. This manuscript examines this claim and argues that it arises because olfactory illusions are not typically accompanied by an awareness of their illusory nature. To demonstrate that olfactory illusions do occur, the relevant empirical literature is reviewed, by examining instances of where the same stimulus results in different percepts, and of where different stimuli result in the same percept. The final part of the manuscript evaluates the evidence favoring the existence of olfactory illusions, and then examines why they may not typically be accompanied by awareness. Three contributory mechanisms are discussed, relating to difficulty of verification and paucity of olfactory knowledge, the role of change blindness, and restricted access consciousness in this sense.

  9. Enthalpies of mixing and intermolecular interactions in the 1-octanol-dimethylformamide system at 298-318 K

    NASA Astrophysics Data System (ADS)

    Smirnova, N. L.; Kustov, A. V.

    2013-05-01

    The heat effects of solution of N,N-dimethylformamide (DMF) and 1-octanol (OctOH) in the DMF (1)-OctOH (2) system are measured over the range of compositions using a variable-temperature isothermal-shell calorimeter at 298, 308, and 318 K. The partial molar enthalpies of the binary mixture components and the enthalpies and heat capacities of mixing are determined. It is found that the amide-alcohol mixing is strongly endothermic and very weakly depends on temperature. The enthalpy and specific heat parameters of binary and ternary interactions between the DMF molecules in OctOH and the OctOH molecules in DMF are determined in terms of the virial expansion technique, and it is shown that the two nonelectrolytes exhibit a tendency to homoassociation.

  10. Pump-Probe Spectroscopy of Thermal Cis-Trans Isomerization Process of Methyl Red in 1-Octanol

    NASA Astrophysics Data System (ADS)

    Joukai, Tatsuya; Kita, Kenji; Yano, Ryuzi

    Thermal cis-trans isomerization process of Methyl Red in 1-Octanol at room temperature was studied by pump-probe spectroscopy. The isomerization rate increased as the dye concentration was increased. However, at concentrations above ~ 3 × 10-5 mol/L, the isomerization rate became almost constant regardless of the dye concentration. We interpreted that the concentration dependence of the thermal isomerization rate was caused by the creation of hydrogen-bonded dimer molecules. When a dimer is formed, one of the dye molecules which form the dimer easily changes its form from the cis isomer to the trans isomer. As the dye concentration is increased, the ratio of dyes which form dimer molecules will increase. When the dye concentration is high enough, most dye molecules form dimer molecules. Thus the isomerization rate averaged over the dye molecules is constant.

  11. Aqueous solubilities, vapor pressures, and 1-octanol-water partition coefficients for C9-C14 linear alkylbenzenes

    USGS Publications Warehouse

    Sherblom, P.M.; Gschwend, P.M.; Eganhouse, R.P.

    1992-01-01

    Measurements and estimates of aqueous solubilities, 1-octanol-water partition coefficients (Kow), and vapor pressures were made for 29 linear alkylbenzenes having alkyl chain lengths of 9-14 carbons. The ranges of values observed were vapor pressures from 0.002 to 0.418 Pa, log Kow, from 6.83 to 9.95, and aqueous solubilities from 4 to 38 nmol??L-1. Measured values exhibited a relationship to both the alkyl chain length and the position of phenyl substitution on the alkyl chain. Measurement of the aqueous concentrations resulting from equilibration of a mixture of alkylbenzenes yielded higher than expected values, indicating cosolute or other interactive effects caused enhanced aqueous concentrations of these compounds. ?? 1992 American Chemical Society.

  12. Viscosities and densities for heptane + 1-pentanol, + 1-hexanol, + 1-heptanol, + 1-octanol, + 1-decanol, and + 1-dodecanol at 298.15 K and 308.15 K

    SciTech Connect

    Sastry, N.V.; Valand, M.K.

    1996-11-01

    Densities and viscosities for heptane + 1-pentanol, + 1-hexanol, + 1-heptanol, + 1-octanol, + 1-decanol, and + 1-dodecanol are reported at (298.15 K and 308.15) K. The viscosity deviations were calculated. The mixture viscosity data were fitted to the semiempirical equations of Grunberg-Nissan, Heric, McAllister, and Auslander.

  13. An open-label, single-dose, crossover study of the pharmacokinetics and metabolism of two oral formulations of 1-octanol in patients with essential tremor.

    PubMed

    Nahab, Fatta B; Wittevrongel, Loretta; Ippolito, Dominic; Toro, Camilo; Grimes, George J; Starling, Judith; Potti, Gopal; Haubenberger, Dietrich; Bowen, Daniel; Buchwald, Peter; Dong, Chuanhui; Kalowitz, Daniel; Hallett, Mark

    2011-10-01

    Existing therapeutic options for management of essential tremor are frequently limited by poor efficacy and adverse effects. Likely the most potent tremor suppressant used is ethanol, although its use is prohibitive due to a brief therapeutic window, and the obvious implications of excessive alcohol use. Longer-chain alcohols have been shown to suppress tremor in harmaline animal models, and appear to be safe and well tolerated in 2 prior studies in humans. Here we report on the findings of a phase I/II study of 1-octanol designed to explore pharmacokinetics, efficacy, and safety. The most significant finding was the identification of octanoic acid as the product of rapid 1-octanol metabolism. Furthermore, the temporal profile of efficacy closely matches the plasma concentration of octanoic acid. Therefore, these findings identify a novel class of compound (e.g., carboxylic acids) with tremor suppressive properties in ET. Administration of 1-octanol also appears to be safe based on various measures collected. Essential tremor (ET) is the most common tremor disorder, with tremors occurring during static posturing or movement. These tremors are known to briefly improve in many cases after alcohol (ethanol) consumption. Two previous studies of a longer chain alcohol, 1-octanol, have demonstrated longer duration tremor-suppressive effects without the occurrence of intoxication. The aim of this study was to characterize the pharmacokinetics of 1-octanol and its primary metabolite octanoic acid using two formulations, along with additional safety and efficacy measures. Participants with proven ethanol-responsive ET were recruited into 1 of 2 parts: (part A) a dose escalation study (1-64 mg/kg; n = 4), and (part B) a fixed dose (64 mg/kg; n = 10) balanced, open-label crossover design. Two participants in part B then completed an exploratory part C evaluating 128 mg/kg.Plasma samples were collected at 10 intervals during a 6-hour period postingestion. Efficacy was

  14. Dispersion stability of 1-octanethiol coated Cu nanoparticles in a 1-octanol solvent for the application of nanoink

    NASA Astrophysics Data System (ADS)

    Cho, Danee; Baik, Jong-Hwan; Choi, Da-hyun; Lee, Caroline Sunyong

    2014-08-01

    Conductive ink with Copper nanoparticles (Cu NPs) has various advantages compared with conventional ink, such as good electrical conductivity and low cost. However, it suffers through easily oxidization problem, leading to an unstable electrical conductivity, which decreases over time. Therefore, it is important to prevent (or least minimize) oxidation of the Cu NPs. In this study, Cu NPs with diameter of 50 nm were coated with 1-octanethiol (CH3(CH2)7SH) in a high-vacuum condition (5.33 × 10-4 Pa). The coating conditions were systematically varied to investigate the effect on the coating thicknesses. Coated Cu NPs were dispersed in 1-octanol to form the conductive ink, and the dispersion behavior was studied as a function of the thickness of the 1-octanethiol coating. The thickness of the coating layer was characterized using transmission electron microscopy and X-ray spectroscopy analysis, and was found to be 3 nm, 6 nm, and 10 nm. The dispersion stability of the inks was characterized by Turbiscan dispersion stability and viscosity measurements, and it was found that the copper nanoink formed using Cu NPs with a 6-nm-thick coating exhibited the most stable dispersion properties.

  15. Ring-size and substituent effects in the solvent extraction of alkali metal nitrates by crown ethers in 1,2-dichloroethane and 1-octanol

    SciTech Connect

    Sachleben, R.A.; Deng, Y.; Bailey, D.R.; Moyer, B.A.

    1996-11-01

    The extraction of alkali metal nitrate salts by solutions of crown ethers in each of the two diluents 1,2-dichloroethane and 1-octanol has been surveyed. The crown ethers include 18-crown-6, 21-crown-7, and 24-crown-8 ethers bearing cyclohexano, benzo, t-alkylbenzo, and/or furano substituents. The extraction efficiencies of the different crown ethers are examined in terms of ring-size, substituent, and solvent effects. Partition ratios for the crown ethers between water and either 1,2-dichloroethane or 1-octanol are discussed. The extraction selectivities, expressed as the separation factor for cesium over sodium, are examined in relation to crown ether structure. 62 refs., 5 figs., 4 tabs.

  16. Crystal structure of [Eu(CyMe4-BTBP)2κ2O,O'-(NO3)](NO3)2·n-C8H17OH and its structure in 1-octanol solution.

    PubMed

    Lundberg, Daniel; Persson, Ingmar; Ekberg, Christian

    2013-03-21

    The structure of the [Eu(CyMe(4)-BTBP)(2)(NO(3))(n)]((3-n)+) complex in 1-octanol solution and solid state has been determined by EXAFS and X-ray crystallography. The crystal structure shows that 1-octanol binds only to the europium(III)-coordinated BTBP molecules through weak van der Waals forces, making it the first indication of the role of the extraction solvent.

  17. Identity Matching-to-Sample with Olfactory Stimuli in Rats

    ERIC Educational Resources Information Center

    Pena, Tracy; Pitts, Raymond C.; Galizio, Mark

    2006-01-01

    Identity matching-to-sample has been difficult to demonstrate in rats, but most studies have used visual stimuli. There is evidence that rats can acquire complex forms of olfactory stimulus control, and the present study explored the possibility that identity matching might be facilitated in rats if olfactory stimuli were used. Four rats were…

  18. Stimulus Control and Compounding with Ambient Odor as a Discriminative Stimulus on a Free-Operant Baseline

    PubMed Central

    Cohn, Scott I; Weiss, Stanley J

    2007-01-01

    Previous experiments have demonstrated that the simultaneous presentation of independently established discriminative stimuli can control rates of operant responding substantially higher than the rates occasioned by the individual stimuli. This “additive summation” phenomenon has been shown with a variety of different reinforcers (e.g., food, water, shock avoidance, cocaine, and heroin). Discriminative stimuli previously used in such studies have been limited to the visual and auditory sensory modalities. The present experiment sought to (1) establish stimulus control on a free-operant baseline with an ambient olfactory discriminative stimulus, (2) compare olfactory control to that produced with an auditory discriminative stimulus, and (3) determine whether compounding independently established olfactory and auditory discriminative stimuli produces additive summation. Rats lever pressed for food on a variable-interval schedule in the presence of either a tone or an odor, with comparable control developed to each stimulus. In the absence of these stimuli responding was not reinforced. During stimulus compounding tests, the tone-plus-odor compound occasioned more than double the responses occasioned by either the tone or odor presented individually. Thus, the current study (1) established stimulus control with an ambient olfactory discriminative stimulus in a traditional free-operant setting and (2) extended the generality of stimulus-compounding effects by demonstrating additive summation when olfactory and auditory discriminative stimuli were presented simultaneously. PMID:17465315

  19. Partition coefficients of some environmentally important organic compounds between 1-octanol and water from reversed-phase high-performance liquid chromatography

    SciTech Connect

    Ritter, S.; Hauthal, W.H. . Inst. fuer Physikalische Chemie); Maurer, G. . Lehrstuhl fuer Technische Thermodynamik)

    1994-07-01

    1-Octanol/water partition coefficients in infinite dilution of several phenol, indole, biphenyl, and naphthalene derivatives, a few polycyclic aromatic compounds, and some polyfunctional haloaromatics determined by using reversed-phase high-performance liquid chromatography (RP-HPLC) are reported. These data may be used for estimating the ecotoxicological impact of those compounds identified in brown coal liquids (e.g., hydroxyaromatic compounds), as well as for the extension of methods to correlate and predict partition coefficients in organic/aqueous liquid phases.

  20. Olfactory Blocking and Odorant Similarity in the Honeybee

    ERIC Educational Resources Information Center

    Gerber, Bertram; Giurfa, Martin; Guerrieri, Fernando; Lachnit, Harald

    2005-01-01

    Blocking occurs when previous training with a stimulus A reduces (blocks) subsequent learning about a stimulus B, when A and B are trained in compound. The question of whether blocking exists in olfactory conditioning of proboscis extension reflex (PER) in honeybees is under debate. The last published accounts on blocking in honeybees state that…

  1. Olfactory neuroblastoma

    SciTech Connect

    O'Connor, T.A.; McLean, P.; Juillard, G.J.; Parker, R.G.

    1989-06-15

    Fifteen patients with olfactory neuroblastoma were treated during the 17-year period of 1969 to 1986. Data was analyzed with respect to age at presentation, sex, presenting signs and symptoms, stage, and results of treatment. Age ranged from 4 to 67 years with the median age being 27 years. Median follow-up was 8 years. Local control was achieved in nine of nine patients or 100% with successful surgical resection, i.e., minimal residual disease, followed by postoperative radiation therapy (45 to 65 Gy) was employed. There were no distant failures when the primary site was controlled. Regional lymph node metastases were infrequent: only 13% (two of 15 patients) presented with positive nodes. Three of four patients treated initially with surgery alone had a local recurrence, two of which were successfully salvaged by combined therapy. There were four patients treated with radiation therapy alone: three had persistent disease after radiation therapy, and one patient was controlled with 65 Gy. Olfactory neuroblastoma has a propensity to recur locally when treated with surgery alone. The authors' experience suggests excellent local control can be achieved with surgery immediately followed by radiation therapy. Thus the authors recommend planned combined treatment for all resectable lesions.

  2. Certification of the reference material of water content in water saturated 1-octanol by Karl Fischer coulometry, Karl Fischer volumetry and quantitative nuclear magnetic resonance.

    PubMed

    Wang, Haifeng; Ma, Kang; Zhang, Wei; Li, Jia; Sun, Guohua; Li, Hongmei

    2012-10-15

    Certified reference materials (CRMs) of water content are widely used in the calibration and validation of Karl Fischer coulometry and volumetry. In this study, the water content of the water saturated 1-octanol (WSO) CRM was certified by Karl Fischer coulometry, volumetry and quantitative nuclear magnetic resonance (Q NMR). The water content recovery by coulometry was 99.76% with a diaphragm-less electrode and Coulomat AG anolyte. The relative bias between the coulometry and volumetry results was 0.06%. In Q NMR, the water content of WSO is traceable to the International System (SI) of units through the purity of internal standard. The relative bias of water content in WSO between Q NMR and volumetry was 0.50%. The consistency of results for these three independent methods improves the accuracy of the certification of the RM. The certified water content of the WSO CRM was 4.76% with an expanded uncertainty of 0.09%.

  3. Responses of the Rat Olfactory Epithelium to Retronasal Air Flow

    PubMed Central

    Scott, John W.; Acevedo, Humberto P.; Sherrill, Lisa; Phan, Maggie

    2008-01-01

    Responses of the rat olfactory epithelium were assessed with the electroolfactogram while odorants were presented to the external nares with an artificial sniff or to the internal nares by positive pressure. A series of seven odorants that varied from very polar, hydrophilic odorants to very non-polar, hydrophobic odorants were used. While the polar odorants activated the dorsal olfactory epithelium when presented by the external nares (orthonasal presentation), they were not effective when forced through the nasal cavity from the internal nares (retronasal presentation). However, the non-polar odorants were effective in both stimulus modes. These results were independent of stimulus concentration or of humidity of the carrier air. Similar results were obtained with multiunit recording from olfactory bulb. These results help to explain why human investigations often report differences in the sensation or ability to discriminate odorants presented orthonasally vs. retronasally. The results also strongly support the importance of odorant sorption in normal olfactory processes. PMID:17215498

  4. H2-driven biotransformation of n-octane to 1-octanol by a recombinant Pseudomonas putida strain co-synthesizing an O2-tolerant hydrogenase and a P450 monooxygenase.

    PubMed

    Lonsdale, Thomas H; Lauterbach, Lars; Honda Malca, Sumire; Nestl, Bettina M; Hauer, Bernhard; Lenz, Oliver

    2015-11-21

    An in vivo biotransformation system is presented that affords the hydroxylation of n-octane to 1-octanol on the basis of NADH-dependent CYP153A monooxygenase and NAD(+)-reducing hydrogenase heterologously synthesized in a bacterial host. The hydrogenase sustains H2-driven NADH cofactor regeneration even in the presence of O2, the co-substrate of monooxygenase.

  5. The Presentation of Olfactory-Trigeminal Mixed Stimuli Increases the Response to Subsequent Olfactory Stimuli.

    PubMed

    Walliczek-Dworschak, Ute; Poncelet, Johan; Baum, Daniel; Baki, Ramona; Sinding, Charlotte; Warr, Jonathan; Hummel, Thomas

    2017-01-09

    The aim of this study was to evaluate the effect of (1) the addition of trigeminal stimuli to an olfactory stimulus and (2) the congruence in the odorous mixture after repeated odor presentation. Twenty-five normosmic volunteers were enrolled and presented stimulation blocks, consisting of three habituation stimuli (H) (orange odor), one dishabituation (DH) (control condition, orange odor; congruent condition, orange odor + CO2; incongruent condition, orange odor + l-isopulegol), and one dishabituated stimulus (D) (orange odor). Olfactory event-related potentials were analyzed. Response amplitudes differed significantly in the incongruent condition (N1P2 between H3 and D; peak to peak N1P2 at electrode positions Cz, Fz, and Pz; response amplitudes between H3 and DH). The addition of CO2 modified the perception of orange odor, pronouncing a fruity note, whereas the addition of l-isopulegol as a DH pronounced the l-isopulegol note. This study provides evidence that incongruent trigeminal-olfactory stimulants increase the response to subsequent olfactory stimulus.

  6. Pseudohydroxide Extraction from Aqueous Sodium Hydroxide Solutions with 3,5-di-tert-Butylphenol in Isopar® L Modified with 1-Octanol

    SciTech Connect

    Lumetta, Gregg J.; Levitskaia, Tatiana G.

    2006-06-01

    Pseudohydroxide extraction (PHE) was investigated for recovery of sodium hydroxide (NaOH) from alkaline process solutions. PHE relies on the deprotonation of a lipophilic weak acid by hydroxide ion with concomitant transfer of sodium ion into an organic phase. Contact of the sodium-loaded organic phase with water results in the reconstitution of the extractant in the organic phase and NaOH in the aqueous phase, thus leading to a process in which NaOH equivalents are transferred from an alkaline feed solution to an aqueous stripping solution. In this work, we researched PHE using a process-friendly diluent—Isopar® L. The lipophilic cation exchanger 3,5-di-tert-butylphenol (35-DTBP) was used as the extractant. The Isopar® L diluent was modified with 1-octanol to improve its solvation properties and the solubility of 35-DTBP so that practical Na+ concentrations could be achieved in the process solvent. The PHE mechanism at process-relevant conditions was explored by Raman and FTIR spectroscopic measurements. Electrospray mass spectroscopic results indicated extensive aggregation of the sodium phenolate at high Na+ loading. An equilibrium computer modeling suggested that the Na+ extraction behavior can be largely explained by the formation of 1:1 and 1:2 Na/35-DTBP species in the organic phase. Extraction isotherms obtained using caustic leaching simulant solutions indicate the potential utility of this approach for recycling NaOH from complex alkaline mixtures.

  7. Olfactory phenotypic expression unveils human aging

    PubMed Central

    Mazzatenta, Andrea; Cellerino, Alessandro; Origlia, Nicola; Barloscio, Davide; Sartucci, Ferdinando; Giulio, Camillo Di; Domenici, Luciano

    2016-01-01

    The mechanism of the natural aging of olfaction and its declinein the absence of any overt disease conditions remains unclear. Here, we investigated this mechanism through measurement of one of the parameters of olfactory function, the absolute threshold, in a healthy population from childhood to old age. The absolute olfactory threshold data were collected from an Italian observational study with 622 participants aged 5-105 years. A subjective testing procedure of constant stimuli was used, which was also compared to the ‘staircase’ method, with the calculation of the reliability. The n-butanol stimulus was used as an ascending series of nine molar concentrations that were monitored using an electronic nose. The data were analyzed using nonparametric statistics because of the multimodal distribution. We show that the age-related variations in the absolute olfactory threshold are not continuous; instead, there are multiple olfactory phenotypes. Three distinct age-related phenotypes were defined, termed as ‘juvenile’, ‘mature’ and ‘elder’. The frequency of these three phenotypes depends on age. Our data suggest that the sense of smell does not decrease linearly with aging. Our findings provide the basis for further understanding of olfactory loss as an anticipatory sign of aging and neurodegenerative processes. PMID:27027240

  8. Appetitive but Not Aversive Olfactory Conditioning Modifies Antennal Movements in Honeybees

    ERIC Educational Resources Information Center

    Cholé, Hanna; Junca, Pierre; Sandoz, Jean-Christophe

    2015-01-01

    In honeybees, two olfactory conditioning protocols allow the study of appetitive and aversive Pavlovian associations. Appetitive conditioning of the proboscis extension response (PER) involves associating an odor, the conditioned stimulus (CS) with a sucrose solution, the unconditioned stimulus (US). Conversely, aversive conditioning of the sting…

  9. Binaral interaction and centrifugal input enhances spatial contrast in olfactory bulb activation.

    PubMed

    Singer, Benjamin H; Kim, Soyoun; Zochowski, Michal

    2007-01-01

    We used paired-pulse odorant stimulation, with a conditioning stimulus delivered either ipsilateral or contralateral to a test stimulus, to unmask the effects of centrifugal feedback on olfactory bulb responses. In reptiles and mammals there are no direct connections between the paired olfactory bulbs, and thus all information transfer between the olfactory bulbs depends on feedback from retrobulbar structures. We measured odor-induced activity in the turtle olfactory bulb using a voltage-sensitive dye and a 464-element photodiode array, which allowed us to monitor the spatial variation in activation of the olfactory bulb. We found that both contralateral and ipsilateral conditioning stimuli evoked long-lasting inhibition of olfactory bulb activation. In contrast to previous studies using local field potential recording to monitor activity at a single site, we found that this inhibition increased contrast in the spatial patterning of activation over the dorsal surface of the olfactory bulb. Inhibition was also increased when different odorants were used as conditioning and test stimuli, suggesting a role for centrifugal feedback in olfactory discrimination. These results highlight the functional importance of centrifugal feedback and information processing in a broadly distributed olfactory network.

  10. Variation in complex olfactory stimuli and its influence on odour recognition.

    PubMed Central

    Wrigh, Geraldine A.; Smith, Brian H.

    2004-01-01

    Natural olfactory stimuli are often complex and highly variable. The olfactory systems of animals are likely to have evolved to use specific features of olfactory stimuli for identification and discrimination. Here, we train honeybees to learn chemically defined odorant mixtures that systematically vary from trial to trial and then examine how they generalize to each odorant present in the mixture. An odorant that was present at a constant concentration in a mixture becomes more representative of the mixture than other variable odorants. We also show that both variation and intensity of a complex olfactory stimulus affect the rate of generalization by honeybees to subsequent olfactory stimuli. These results have implications for the way that all animals perceive and attend to features of olfactory stimuli. PMID:15058390

  11. Mind the gap: olfactory trace conditioning in honeybees.

    PubMed

    Szyszka, Paul; Demmler, Christiane; Oemisch, Mariann; Sommer, Ludwig; Biergans, Stephanie; Birnbach, Benjamin; Silbering, Ana F; Galizia, C Giovanni

    2011-05-18

    Trace conditioning is a form of classical conditioning, where a neutral stimulus (conditioned stimulus, CS) is associated with a following appetitive or aversive stimulus (unconditioned stimulus, US). Unlike classical delay conditioning, in trace conditioning there is a stimulus-free gap between CS and US, and thus a poststimulus neural representation (trace) of the CS is required to bridge the gap until its association with the US. The properties of such stimulus traces are not well understood, nor are their underlying physiological mechanisms. Using behavioral and physiological approaches, we studied appetitive olfactory trace conditioning in honeybees. We found that single-odor presentation created a trace containing information about odor identity. This trace conveyed odor information about the initial stimulus and was robust against interference by other odors. Memory acquisition decreased with increasing CS-US gap length. The maximum learnable CS-US gap length could be extended by previous trace-conditioning experience. Furthermore, acquisition improved when an additional odor was presented during the CS-US gap. Using calcium imaging, we tested whether projection neurons in the primary olfactory brain area, the antennal lobe, contain a CS trace. We found odor-specific persistent responses after stimulus offset. These post-odor responses, however, did not encode the CS trace, and perceived odor quality could be predicted by the initial but not by the post-odor response. Our data suggest that olfactory trace conditioning is a less reflexive form of learning than classical delay conditioning, indicating that odor traces might involve higher-level cognitive processes.

  12. Muscarinic ACh Receptors Contribute to Aversive Olfactory Learning in Drosophila

    PubMed Central

    Silva, Bryon; Molina-Fernández, Claudia; Ugalde, María Beatriz; Tognarelli, Eduardo I.; Angel, Cristian; Campusano, Jorge M.

    2015-01-01

    The most studied form of associative learning in Drosophila consists in pairing an odorant, the conditioned stimulus (CS), with an unconditioned stimulus (US). The timely arrival of the CS and US information to a specific Drosophila brain association region, the mushroom bodies (MB), can induce new olfactory memories. Thus, the MB is considered a coincidence detector. It has been shown that olfactory information is conveyed to the MB through cholinergic inputs that activate acetylcholine (ACh) receptors, while the US is encoded by biogenic amine (BA) systems. In recent years, we have advanced our understanding on the specific neural BA pathways and receptors involved in olfactory learning and memory. However, little information exists on the contribution of cholinergic receptors to this process. Here we evaluate for the first time the proposition that, as in mammals, muscarinic ACh receptors (mAChRs) contribute to memory formation in Drosophila. Our results show that pharmacological and genetic blockade of mAChRs in MB disrupts olfactory aversive memory in larvae. This effect is not explained by an alteration in the ability of animals to respond to odorants or to execute motor programs. These results show that mAChRs in MB contribute to generating olfactory memories in Drosophila. PMID:26380118

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

    ERIC Educational Resources Information Center

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

    2015-01-01

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

  14. Posttraumatic olfactory dysfunction.

    PubMed

    Coelho, Daniel H; Costanzo, Richard M

    2016-04-01

    Impairment of smell may occur following injury to any portion of the olfactory tract, from nasal cavity to brain. A thorough understanding of the anatomy and pathophysiology combined with comprehensively obtained history, physical exam, olfactory testing, and neuroimaging may help to identify the mechanism of dysfunction and suggest possible treatments. Although most olfactory deficits are neuronal mediated and therefore currently unable to be corrected, promising technology may provide novel treatment options for those most affected. Until that day, patient counseling with compensatory strategies and reassurance is essential for the maintenance of safety and QoL in this unique and challenging patient population.

  15. Suppression of Odorant Responses by Odorants in Olfactory Receptor Cells

    NASA Astrophysics Data System (ADS)

    Kurahashi, Takashi; Lowe, Graeme; Gold, Geoffrey H.

    1994-07-01

    Odorants activate an inward current in vertebrate olfactory receptor cells. Here it is shown, in receptor cells from the newt, that odorants can also suppress this current, by a mechanism that is distinct from inhibition and adaptation. Suppression provides a simple explanation for two seemingly unrelated phenomena: the anomalously long latency of olfactory transduction and the existence of an "off response" at the end of a prolonged stimulus. Suppression may influence the perception of odorants by masking odorant responses and by sharpening the odorant specificities of single cells.

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

    PubMed

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

    2017-02-03

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

  17. Effects of odor stimulation on antidromic spikes in olfactory sensory neurons.

    PubMed

    Scott, John W; Sherrill, Lisa

    2008-12-01

    Spikes were evoked in rat olfactory sensory neuron (OSN) populations by electrical stimulation of the olfactory bulb nerve layer in pentobarbital anesthetized rats. The latencies and recording positions for these compound spikes showed that they originated in olfactory epithelium. Dual simultaneous recordings indicated conduction velocities in the C-fiber range, around 0.5 m/s. These spikes are concluded to arise from antidromically activated olfactory sensory neurons. Electrical stimulation at 5 Hz was used to track changes in the size and latency of the antidromic compound population spike during the odor response. Strong odorant stimuli suppressed the spike size and prolonged its latency. The latency was prolonged throughout long odor stimuli, indicating continued activation of olfactory receptor neuron axons. The amounts of spike suppression and latency change were strongly correlated with the electroolfactogram (EOG) peak size evoked at the same site across odorants and across stimulus intensities. We conclude that the curve of antidromic spike suppression gives a reasonable representation of spiking activity in olfactory sensory neurons driven by odorants and that the correlation of peak spike suppression with the peak EOG shows the accuracy of the EOG as an estimate of intracellular potential in the population of olfactory sensory neurons. In addition, these results have important implications about traffic in olfactory nerve bundles. We did not observe multiple peaks corresponding to stimulated and unstimulated receptor neurons. This suggests synchronization of spikes in olfactory nerve, perhaps by ephaptic interactions. The long-lasting effect on spike latency shows that action potentials continue in the nerve throughout the duration of an odor stimulus in spite of many reports of depolarization block in olfactory receptor neuron cell bodies. Finally, strong odor stimulation caused almost complete block of antidromic spikes. This indicates that a very

  18. Reversing Stimulus Timing in Visual Conditioning Leads to Memories with Opposite Valence in Drosophila

    PubMed Central

    Vogt, Katrin; Yarali, Ayse; Tanimoto, Hiromu

    2015-01-01

    Animals need to associate different environmental stimuli with each other regardless of whether they temporally overlap or not. Drosophila melanogaster displays olfactory trace conditioning, where an odor is followed by electric shock reinforcement after a temporal gap, leading to conditioned odor avoidance. Reversing the stimulus timing in olfactory conditioning results in the reversal of memory valence such that an odor that follows shock is later on approached (i.e. relief conditioning). Here, we explored the effects of stimulus timing on memory in another sensory modality, using a visual conditioning paradigm. We found that flies form visual memories of opposite valence depending on stimulus timing and can associate a visual stimulus with reinforcement despite being presented with a temporal gap. These results suggest that associative memories with non-overlapping stimuli and the effect of stimulus timing on memory valence are shared across sensory modalities. PMID:26430885

  19. Acetylcholine and Olfactory Perceptual Learning

    ERIC Educational Resources Information Center

    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…

  20. Stimulus Reporting Advances

    ERIC Educational Resources Information Center

    McNeil, Michele

    2009-01-01

    Faced with their first reporting deadlines for economic-stimulus aid to education, school districts are toiling over how every stimulus penny has been spent so far and how many jobs have been saved--numbers that will be scrutinized not just by the public, but by government auditors as well. The American Recovery and Reinvestment Act, passed by…

  1. Intermittency Coding in the Primary Olfactory System: A Neural Substrate for Olfactory Scene Analysis

    PubMed Central

    Park, Il Memming; Bobkov, Yuriy V.; Ache, Barry W.

    2014-01-01

    The spatial and temporal characteristics of the visual and acoustic sensory input are indispensable attributes for animals to perform scene analysis. In contrast, research in olfaction has focused almost exclusively on how the nervous system analyzes the quality and quantity of the sensory signal and largely ignored the spatiotemporal dimension especially in longer time scales. Yet, detailed analyses of the turbulent, intermittent structure of water- and air-borne odor plumes strongly suggest that spatio-temporal information in longer time scales can provide major cues for olfactory scene analysis for animals. We show that a bursting subset of primary olfactory receptor neurons (bORNs) in lobster has the unexpected capacity to encode the temporal properties of intermittent odor signals. Each bORN is tuned to a specific range of stimulus intervals, and collectively bORNs can instantaneously encode a wide spectrum of intermittencies. Our theory argues for the existence of a novel peripheral mechanism for encoding the temporal pattern of odor that potentially serves as a neural substrate for olfactory scene analysis. PMID:24431452

  2. Stimulus responsive nanoparticles

    NASA Technical Reports Server (NTRS)

    Cairns, Darren Robert (Inventor); Huebsch, Wade W. (Inventor); Sierros, Konstantinos A. (Inventor); Shafran, Matthew S. (Inventor)

    2013-01-01

    Disclosed are various embodiments of methods and systems related to stimulus responsive nanoparticles. In one embodiment includes a stimulus responsive nanoparticle system, the system includes a first electrode, a second electrode, and a plurality of elongated electro-responsive nanoparticles dispersed between the first and second electrodes, the plurality of electro-responsive nanorods configured to respond to an electric field established between the first and second electrodes.

  3. Stimulus Responsive Nanoparticles

    NASA Technical Reports Server (NTRS)

    Cairns, Darran Robert (Inventor); Huebsch, Wade W. (Inventor); Sierros, Konstantinos A. (Inventor); Shafran, Matthew S. (Inventor)

    2015-01-01

    Disclosed are various embodiments of methods and systems related to stimulus responsive nanoparticles. In one embodiment includes a stimulus responsive nanoparticle system, the system includes a first electrode, a second electrode, and a plurality of elongated electro-responsive nanoparticles dispersed between the first and second electrodes, the plurality of electro-responsive nanorods configured to respond to an electric field established between the first and second electrodes.

  4. Primary Events in Olfactory Reception

    DTIC Science & Technology

    1993-01-08

    sustentacular cells and Bowman’s glands and that it is deposited in the lower mucus layer of olfactory neuroepithelium. Next, we extracted mRNA from...protrude from the dendritic tips of olfactory receptor neurons. These cilia are surrounded by a layer of mucus that lines the olfactory...neuroepithelium. Odorants that enter the nasal cavity with the inspired air partition into and diffuse through this aqueous mucus layer on their way to odorant

  5. Olfactory toxicity in fishes.

    PubMed

    Tierney, Keith B; Baldwin, David H; Hara, Toshiaki J; Ross, Peter S; Scholz, Nathaniel L; Kennedy, Christopher J

    2010-01-21

    Olfaction conveys critical environmental information to fishes, enabling activities such as mating, locating food, discriminating kin, avoiding predators and homing. All of these behaviors can be impaired or lost as a result of exposure to toxic contaminants in surface waters. Historically, teleost olfaction studies have focused on behavioral responses to anthropogenic contaminants (e.g., avoidance). More recently, there has been a shift towards understanding the underlying mechanisms and functional significance of contaminant-mediated changes in fish olfaction. This includes a consideration of how contaminants affect the olfactory nervous system and, by extension, the downstream physiological and behavioral processes that together comprise a normal response to naturally occurring stimuli (e.g., reproductive priming or releasing pheromones). Numerous studies spanning several species have shown that ecologically relevant exposures to common pollutants such as metals and pesticides can interfere with fish olfaction and disrupt life history processes that determine individual survival and reproductive success. This represents one of the pathways by which toxic chemicals in aquatic habitats may increasingly contribute to the decline and at-risk status of many commercially and ecologically important fish stocks. Despite our emerging understanding of the threats that pollution poses for chemical communication in aquatic communities, many research challenges remain. These include: (1) the determination of specific mechanisms of toxicity in the fish olfactory sensory epithelium; (2) an understanding of the impacts of complex chemical mixtures; (3) the capacity to assess olfactory toxicity in fish in situ; (4) the impacts of toxins on olfactory-mediated behaviors that are still poorly understood for many fish species; and (5) the connections between sublethal effects on individual fish and the long-term viability of wild populations. This review summarizes and integrates

  6. An Evaluation of a Stimulus Preference Assessment of Auditory Stimuli for Adolescents with Developmental Disabilities

    ERIC Educational Resources Information Center

    Horrocks, Erin; Higbee, Thomas S.

    2008-01-01

    Previous researchers have used stimulus preference assessment (SPA) methods to identify salient reinforcers for individuals with developmental disabilities including tangible, leisure, edible and olfactory stimuli. In the present study, SPA procedures were used to identify potential auditory reinforcers and determine the reinforcement value of…

  7. Recent Trend in Development of Olfactory Displays

    NASA Astrophysics Data System (ADS)

    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.

  8. It takes two—coincidence coding within the dual olfactory pathway of the honeybee

    PubMed Central

    Brill, Martin F.; Meyer, Anneke; Rössler, Wolfgang

    2015-01-01

    To rapidly process biologically relevant stimuli, sensory systems have developed a broad variety of coding mechanisms like parallel processing and coincidence detection. Parallel processing (e.g., in the visual system), increases both computational capacity and processing speed by simultaneously coding different aspects of the same stimulus. Coincidence detection is an efficient way to integrate information from different sources. Coincidence has been shown to promote associative learning and memory or stimulus feature detection (e.g., in auditory delay lines). Within the dual olfactory pathway of the honeybee both of these mechanisms might be implemented by uniglomerular projection neurons (PNs) that transfer information from the primary olfactory centers, the antennal lobe (AL), to a multimodal integration center, the mushroom body (MB). PNs from anatomically distinct tracts respond to the same stimulus space, but have different physiological properties, characteristics that are prerequisites for parallel processing of different stimulus aspects. However, the PN pathways also display mirror-imaged like anatomical trajectories that resemble neuronal coincidence detectors as known from auditory delay lines. To investigate temporal processing of olfactory information, we recorded PN odor responses simultaneously from both tracts and measured coincident activity of PNs within and between tracts. Our results show that coincidence levels are different within each of the two tracts. Coincidence also occurs between tracts, but to a minor extent compared to coincidence within tracts. Taken together our findings support the relevance of spike timing in coding of olfactory information (temporal code). PMID:26283968

  9. Recovery of olfactory function after bilateral bulbectomy.

    PubMed

    Wright, J W; Harding, J W

    1982-04-16

    Mice were trained to discriminate between scented and unscented air. After olfactory bulbs were removed, discrimination was lost, but returned with the formation of synaptic connections between regenerated primary olfactory neurons and the cortex of the forebrain. The acquisition of a second olfactory-mediated task by long-term bulbectomized mice and controls was indistinguishable. The results emphasize the plasticity of the nervous system, correlate the presence of neural connections between olfactory mucosa and forebrain with the recovery of olfactory function, suggest that olfactory-mediated memory resides at least in part outside the olfactory bulbs, and demonstrate that the bulbs are not required for the acquisition of olfactory tasks.

  10. Effects of Caffeine on Olfactory Learning in Crickets.

    PubMed

    Sugimachi, Seigo; Matsumoto, Yukihisa; Mizunami, Makoto; Okada, Jiro

    2016-10-01

    Caffeine is a plant-derived alkaloid that is generally known as a central nervous system (CNS) stimulant. In order to examine the effects of caffeine on higher CNS functions in insects, we used an appetitive olfactory learning paradigm for the cricket Gryllus bimaculatus. Crickets can form significant long-term memories (LTMs) after repetitive training sessions, during which they associate a conditioned stimulus (CS: odor) with an unconditioned stimulus (US: reward). Administration of hemolymphal injections of caffeine established LTM after only single-trial conditioning over a wide range of caffeine dosages (1.6 µµg/kg to 39 mg/kg). We investigated the physiological mechanisms underlying this enhancement of olfactory learning performance pharmacologically, focusing on three major physiological roles of caffeine: 1) inhibition of phosphodiesterase (PDE), 2) agonism of ryanodine receptors, and 3) antagonism of adenosine receptors. Application of drugs relevant to these actions resulted in significant effects on LTM formation. These results suggest that externally applied caffeine enhances LTM formation in insect olfactory learning via multiple cellular mechanisms.

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

    PubMed

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

    2015-09-01

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

  12. Reflections on Stimulus Control

    ERIC Educational Resources Information Center

    Sidman, Murray

    2008-01-01

    The topic of stimulus control is too broad and complex to be traceable here. It would probably take a two-semester course to cover just the highlights of that field's evolution. The more restricted topic of equivalence relations has itself become so broad that even an introductory summary requires more time than we have available. An examination…

  13. Interests and Stimulus Seeking

    ERIC Educational Resources Information Center

    Kish, George B.; Donnenwerth, Gregory V.

    1969-01-01

    Examines relationships between Sensation-Seeking Scale (SSS) and vocational interests measured by the Kuder and Strong Vocational Interest Blank, among alcoholics and undergraduates. Results support construct validity of the SSS and provide further evidence of modes of expression of stimulus-seeking needs in personality. (Author/CJ)

  14. GABAergic feedback signaling into the calyces of the mushroom bodies enables olfactory reversal learning in honey bees

    PubMed Central

    Boitard, Constance; Devaud, Jean-Marc; Isabel, Guillaume; Giurfa, Martin

    2015-01-01

    In reversal learning, subjects first learn to respond to a reinforced stimulus A and not to a non-reinforced stimulus B (A+ vs. B−) and then have to learn the opposite when stimulus contingencies are reversed (A− vs. B+). This change in stimulus valence generates a transitory ambiguity at the level of stimulus outcome that needs to be overcome to solve the second discrimination. Honey bees (Apis mellifera) efficiently master reversal learning in the olfactory domain. The mushroom bodies (MBs), higher-order structures of the insect brain, are required to solve this task. Here we aimed at uncovering the neural circuits facilitating reversal learning in honey bees. We trained bees using the olfactory conditioning of the proboscis extension reflex (PER) coupled with localized pharmacological inhibition of Gamma-AminoButyric Acid (GABA)ergic signaling in the MBs. We show that inhibition of ionotropic but not metabotropic GABAergic signaling into the MB calyces impairs reversal learning, but leaves intact the capacity to perform two consecutive elemental olfactory discriminations with ambiguity of stimulus valence. On the contrary, inhibition of ionotropic GABAergic signaling into the MB lobes had no effect on reversal learning. Our results are thus consistent with a specific requirement of the feedback neurons (FNs) providing ionotropic GABAergic signaling from the MB lobes to the calyces for counteracting ambiguity of stimulus valence in reversal learning. PMID:26283938

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

    PubMed

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

    2014-01-01

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

  16. Olfactory receptor gene expression in tiger salamander olfactory epithelium.

    PubMed

    Marchand, James E; Yang, Xinhai; Chikaraishi, Dona; Krieger, Jurgen; Breer, Heinz; Kauer, John S

    2004-06-28

    Physiological studies of odor-elicited responses from the olfactory epithelium and bulb in the tiger salamander, Ambystoma tigrinum, have elucidated a number of features of olfactory coding that appear to be conserved across several vertebrate species. This animal model has provided an accessible in vivo system for observing individual and ensemble olfactory responses to odorant stimulation using biochemical, neurophysiological, and behavioral assays. In this paper we have complemented these studies by characterizing 35 candidate odorant receptor genes. These receptor sequences are similar to those of the large families of olfactory receptors found in mammals and fish. In situ hybridization, using RNA probes to 20 of these sequences, demonstrates differential distributions of labeled cells across the extent and within the depth of the olfactory epithelium. The distributions of cells labeled with probes to different receptors show spatially restricted patterns that are generally localized to different degrees in medial-lateral and anterior-posterior directions. The patterns of receptor expression in the ventral olfactory epithelium (OE) are mirrored in the dorsal OE. We present a hypothesis as to how the sensory neuron populations expressing different receptor types responding to a particular odorant may relate to the distribution patterns of epithelial and bulbar responses previously characterized using single-unit and voltage-sensitive dye recording methods.

  17. Comparison of two stimulus-delivery systems for measurement of nasal pungency thresholds.

    PubMed

    Cometto-Muñiz, J E; Cain, W S; Hiraishi, T; Abraham, M H; Gola, J M

    2000-06-01

    Using representative members of each of three homologous series of chemicals-ketones, acetates and alcohols-we measured nasal pungency thresholds in anosmics via two stimulus-delivery systems. The first system consists of the fairly commonly used 270 ml, plastic 'squeeze bottles'. The second system consists of 1900 ml, glass vessels with Teflon tubing and nose-pieces. Although bulkier and more susceptible to mechanical breakage, the glass vessels possess advantages that can allow them to provide 'environmentally realistic' chemosensory thresholds, i.e. thresholds closer in absolute values to those that might be obtained under whole-body exposures. Such advantages include a larger volume of the vapor-source to accommodate whole sniffs, and a tight nose-nose-piece connection to avoid stimulus dilution. The outcome revealed that, for every chemical, the glass vessels provided nasal pungency thresholds significantly lower than those provided by the squeeze bottles. The difference amounted, on average, to a factor of 4.6, though the relative potency of the compounds remained the same under both systems. Additionally, when tested with the highest homologues used here, namely, octyl acetate and 1-octanol, anosmics using the glass vessels had little or no difficulty achieving the criterion for threshold whereas they did have difficulty when using the squeeze bottles.

  18. Insight of scent: experimental evidence of olfactory capabilities in the wandering albatross (Diomedea exulans).

    PubMed

    Mardon, J; Nesterova, A P; Traugott, J; Saunders, S M; Bonadonna, F

    2010-02-15

    Wandering albatrosses routinely forage over thousands of kilometres of open ocean, but the sensory mechanisms used in the food search itself have not been completely elucidated. Recent telemetry studies show that some spatial behaviours of the species are consistent with the 'multimodal foraging strategy' hypothesis which proposes that birds use a combination of olfactory and visual cues while foraging at sea. The 'multimodal foraging strategy' hypothesis, however, still suffers from a lack of experimental evidence, particularly regarding the olfactory capabilities of wandering albatrosses. As an initial step to test the hypothesis, we carried out behavioural experiments exploring the sensory capabilities of adult wandering albatrosses at a breeding colony. Three two-choice tests were designed to investigate the birds' response to olfactory and visual stimuli, individually or in combination. Perception of the different stimuli was assessed by comparing the amount of exploration directed towards an 'experimental' display or a 'control' display. Our results indicate that birds were able to perceive the three types of stimulus presented: olfactory, visual and combined. Moreover, olfactory and visual cues were found to have additional effects on the exploratory behaviours of males. This simple experimental demonstration of reasonable olfactory capabilities in the wandering albatross supports the 'multimodal foraging strategy' and is consistent with recent hypotheses of the evolutionary history of procellariiforms.

  19. Olfactory dysfunction in Parkinson's disease.

    PubMed Central

    Hawkes, C H; Shephard, B C; Daniel, S E

    1997-01-01

    OBJECTIVE: To evaluate olfactory function in Parkinson's disease. METHODS: A standardised odour identification test was used, together with an evoked potential assessment with hydrogen sulphide. In addition, histological analysis was performed on the olfactory bulbs of cadavers who died from Parkinson's disease. RESULTS: Over 70% of patients studied (71 of 96) were outside the 95% limit of normal on the identification test in an age matched sample and there was an unusual pattern of selective loss to certain odours, not hitherto described. The evoked potentials were significantly delayed but of comparable amplitude to a control matched population. Of the 73 patients studied only 37 had a technically satisfactory record containing a clear response to both gases and of these, 12 were delayed. For H2S there was more delay on stimulating the right nostril than the left. Some patients with normal smell identification test scores had delayed evoked potentials. In the pathological examination of olfactory bulbs from eight brains, changes characteristic of Parkinson's disease (Lewy bodies) were seen in every olfactory bulb, particularly in the anterior olfactory nucleus, and were sufficiently distinct to allow a presumptive diagnosis of Parkinson's disease. CONCLUSIONS: Olfactory damage in Parkinson's disease is consistent and severe and may provide an important clue to the aetiology of the disease. Images PMID:9153598

  20. Sadness might isolate you in a non-smelling world: olfactory perception and depression

    PubMed Central

    Schablitzky, Sylvia; Pause, Bettina M.

    2014-01-01

    Major depressive disorder (MDD) occurs with a high prevalence among 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 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 have not been 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. PMID:24570666

  1. System identification of Drosophila olfactory sensory neurons.

    PubMed

    Kim, Anmo J; Lazar, Aurel A; Slutskiy, Yevgeniy B

    2011-02-01

    The lack of a deeper understanding of how olfactory sensory neurons (OSNs) encode odors has hindered the progress in understanding the olfactory signal processing in higher brain centers. Here we employ methods of system identification to investigate the encoding of time-varying odor stimuli and their representation for further processing in the spike domain by Drosophila OSNs. In order to apply system identification techniques, we built a novel low-turbulence odor delivery system that allowed us to deliver airborne stimuli in a precise and reproducible fashion. The system provides a 1% tolerance in stimulus reproducibility and an exact control of odor concentration and concentration gradient on a millisecond time scale. Using this novel setup, we recorded and analyzed the in-vivo response of OSNs to a wide range of time-varying odor waveforms. We report for the first time that across trials the response of OR59b OSNs is very precise and reproducible. Further, we empirically show that the response of an OSN depends not only on the concentration, but also on the rate of change of the odor concentration. Moreover, we demonstrate that a two-dimensional (2D) Encoding Manifold in a concentration-concentration gradient space provides a quantitative description of the neuron's response. We then use the white noise system identification methodology to construct one-dimensional (1D) and two-dimensional (2D) Linear-Nonlinear-Poisson (LNP) cascade models of the sensory neuron for a fixed mean odor concentration and fixed contrast. We show that in terms of predicting the intensity rate of the spike train, the 2D LNP model performs on par with the 1D LNP model, with a root mean-square error (RMSE) increase of about 5 to 10%. Surprisingly, we find that for a fixed contrast of the white noise odor waveforms, the nonlinear block of each of the two models changes with the mean input concentration. The shape of the nonlinearities of both the 1D and the 2D LNP model appears to be

  2. Olfactory discrimination in the western lowland gorilla, Gorilla gorilla gorilla.

    PubMed

    Hepper, Peter G; Wells, Deborah L

    2012-04-01

    The olfactory abilities of great apes have been subject to little empirical investigation, save for a few observational reports. This study, using an habituation/dishabituation task, provides experimental evidence for a core olfactory ability, namely, olfactory discrimination, in the gorilla. In Experiment 1, six zoo-housed western lowland gorillas were individually presented with the same odour on four trials, and with a novel odour on the fifth trial. Odours (almond and vanilla) were presented on plastic balls, and behavioural responses of sniffing and chewing/licking the balls were recorded. A second experiment presented the same odour on four trials and no odour on the fifth to examine whether any dishabituation was due to the presence of a new odour or the absence of the familiar odour. Gorillas habituated their behaviour with repeated presentation of the same odour, but dishabituated, i.e. increased sniffing and chewing/licking, when presented with the novel odour. No dishabituation was noted when using water as the stimulus across all trials or when used as the novel odour. Overall, results show that gorillas are able to discriminate between odours.

  3. Experimental evolution of olfactory memory in Drosophila melanogaster.

    PubMed

    Mery, Frederic; Pont, Juliette; Preat, Thomas; Kawecki, Tadeusz J

    2007-01-01

    In order to address the nature of genetic variation in learning performance, we investigated the response to classical olfactory conditioning in "high-learning" Drosophila melanogaster lines previously subject to selection for the ability to learn an association between the flavor of an oviposition medium and bitter taste. In a T-maze choice test, the seven high-learning lines were better at avoiding an odor previously associated with aversive mechanical shock than were five unselected "low-learning" lines originating from the same natural population. Thus, the evolved improvement in learning ability of high-learning lines generalized to another aversion learning task involving a different aversive stimulus (shock instead of bitter taste) and a different behavioral context than that used to impose selection. In this olfactory shock task, the high-learning lines showed improvements in the learning rate as well as in two forms of consolidated memory: anesthesia-resistant memory and long-term memory. Thus, genetic variation underlying the experimental evolution of learning performance in the high-learning lines affected several phases of memory formation in the course of olfactory aversive learning. However, the two forms of consolidated memory were negatively correlated among replicate high-learning lines, which is consistent with a recent hypothesis that these two forms of consolidated memory are antagonistic.

  4. Salivary conditioning with antennal gustatory unconditioned stimulus in an insect.

    PubMed

    Watanabe, Hidehiro; Sato, Chihiro; Kuramochi, Tomokazu; Nishino, Hiroshi; Mizunami, Makoto

    2008-07-01

    Classical conditioning of olfactory conditioning stimulus (CS) with gustatory unconditioned stimulus (US) in insects has been used as a pertinent model for elucidation of neural mechanisms underlying learning and memory. However, a conditioning system in which stable intracellular recordings from brain neurons are feasibly obtained while monitoring the conditioning effect has remained to be established. Recently, we found classical conditioning of salivation in cockroaches Periplaneta americana, in which an odor was associated with sucrose solution applied to the mouth, and this conditioning could be monitored by activities of salivary neurons. Application of gustatory US to the mouth, however, leads to feeding movement accompanying a movement of the brain that prevents stable recordings from brain neurons. Here we investigated whether a gustatory stimulus presented to an antenna could serve as an effective US for producing salivary conditioning. Presentation of sucrose or sodium chloride solution to an antenna induced salivation and also increased activities of salivary neurons. A single pairing trial of an odor with antennal presentation of sucrose or sodium chloride solution produced conditioning of salivation or of activities of salivary neurons. Five pairing trials led to a conditioning effect that lasted for one day. Water or tactile stimulus presented to an antenna was not effective for producing conditioning. The results demonstrate that gustatory US presented to an antenna is as effective as that presented to the mouth for producing salivary conditioning. This conditioning system provides a useful model for studying the neural basis of learning at the level of singly identifiable neurons.

  5. [Olfactory sensory perception].

    PubMed

    Fuentes, Aler; Fresno, María Javiera; Santander, Hugo; Valenzuela, Saúl; Gutiérrez, Mario Felipe; Miralles, Rodolfo

    2011-03-01

    The five senses have had a fundamental importance for survival and socialization of human beings. From an evolutionary point of view the sense of smell is the oldest. This sense has a strong representation within the genome, allowing the existence of many types of receptors that allow us to capture multiple volatile odor producing molecules, sending electrical signals to higher centers to report the outside world. Several cortical areas are activated in the brain, which are interconnected to form an extensive and complex neural network, linking for example, areas involved with memory and emotions, thus giving this sense of perceptual richness. While the concept of flavor is largely related to the sense of taste, smell provides the necessary integration with the rest of the senses and higher functions. Fully understanding the sense of smell is relevant to health professionals. Knowing the characteristics of the receptors, the transduction processes and convergence of information in the higher centers involved, we can properly detect olfactory disorders in our patients.

  6. Compensatory plasticity in the olfactory epithelium: age, timing, and reversibility

    PubMed Central

    Barber, Casey N.

    2015-01-01

    Like other biological systems, olfaction responds “homeostatically” to enduring change in the stimulus environment. This adaptive mechanism, referred to as compensatory plasticity, has been studied almost exclusively in developing animals. Thus it is unknown if this phenomenon is limited to ontogenesis and irreversible, characteristics common to some other forms of plasticity. Here we explore the effects of odor deprivation on the adult mouse olfactory epithelium (OE) using nasal plugs to eliminate nasal airflow unilaterally. Plugs were in place for 2–6 wk after which electroolfactograms (EOGs) were recorded from the occluded and open sides of the nasal cavity. Mean EOG amplitudes were significantly greater on the occluded than on the open side. The duration of plugging did not affect the results, suggesting that maximal compensation occurs within 2 wk or less. The magnitude of the EOG difference between the open and occluded side in plugged mice was comparable to adults that had undergone surgical naris occlusion as neonates. When plugs were removed after 4 wk followed by 2 wk of recovery, mean EOG amplitudes were not significantly different between the always-open and previously plugged sides of the nasal cavity suggesting that this form of plasticity is reversible. Taken together, these results suggest that compensatory plasticity is a constitutive mechanism of olfactory receptor neurons that allows these cells to recalibrate their stimulus-response relationship to fit the statistics of their current odor environment. PMID:26269548

  7. Rapid and continuous activity-dependent plasticity of olfactory sensory input

    PubMed Central

    Cheetham, Claire E. J.; Park, Una; Belluscio, Leonardo

    2016-01-01

    Incorporation of new neurons enables plasticity and repair of circuits in the adult brain. Adult neurogenesis is a key feature of the mammalian olfactory system, with new olfactory sensory neurons (OSNs) wiring into highly organized olfactory bulb (OB) circuits throughout life. However, neither when new postnatally generated OSNs first form synapses nor whether OSNs retain the capacity for synaptogenesis once mature, is known. Therefore, how integration of adult-born OSNs may contribute to lifelong OB plasticity is unclear. Here, we use a combination of electron microscopy, optogenetic activation and in vivo time-lapse imaging to show that newly generated OSNs form highly dynamic synapses and are capable of eliciting robust stimulus-locked firing of neurons in the mouse OB. Furthermore, we demonstrate that mature OSN axons undergo continuous activity-dependent synaptic remodelling that persists into adulthood. OSN synaptogenesis, therefore, provides a sustained potential for OB plasticity and repair that is much faster than OSN replacement alone. PMID:26898529

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

    PubMed

    Gschwend, Olivier; Abraham, Nixon M; Lagier, Samuel; Begnaud, Frédéric; Rodriguez, Ivan; Carleton, Alan

    2015-10-01

    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. We found that overlapping odor-evoked input patterns to the mouse olfactory bulb (OB) were dynamically reformatted in the network on the timescale of a single breath, giving rise to separated patterns of activity in an ensemble of output neurons, mitral/tufted (M/T) cells. Notably, the extent of pattern separation in M/T assemblies predicted 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 stimulus distinction, a process that is sculpted by synaptic inhibition.

  9. Evidence for a role of GABA- and glutamate-gated chloride channels in olfactory memory.

    PubMed

    Boumghar, Katia; Couret-Fauvel, Thomas; Garcia, Mikael; Armengaud, Catherine

    2012-11-01

    In the honeybee, we investigated the role of transmissions mediated by GABA-gated chloride channels and glutamate-gated chloride channels (GluCls) of the mushroom bodies (MBs) on olfactory learning using a single-trial olfactory conditioning paradigm. The GABAergic antagonist picrotoxin (PTX) or the GluCl antagonist L-trans-pyrrolidine-2,4-dicarboxylic acid (L-trans-PDC) was injected alone or in combination into the α-lobes of MBs. PTX impaired early long-term olfactory memory when injected before conditioning or before testing. L-trans-PDC alone induced no significant effect on learning and memory but induced a less specific response to the conditioned odor. When injected before PTX, L-trans-PDC was able to modulate PTX effects. These results emphasize the role of MB GABA-gated chloride channels in consolidation processes and strongly support that GluCls are involved in the perception of the conditioned stimulus.

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

    PubMed Central

    Giridhar, Sonya; Urban, Nathaniel N.

    2012-01-01

    Inhibitory circuits are critical for shaping odor representations in the olfactory bulb. There, individual 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. This late excitation originates from tufted cells, which have intrinsic properties that favor longer latency spiking than mitral cells. Using computational modeling, we show that widely distributed interneuron latency increases 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. PMID:22754503

  11. Evolution of insect olfactory receptors

    PubMed Central

    Missbach, Christine; Dweck, Hany KM; Vogel, Heiko; Vilcinskas, Andreas; Stensmyr, Marcus C; Hansson, Bill S; Grosse-Wilde, Ewald

    2014-01-01

    The olfactory sense detects a plethora of behaviorally relevant odor molecules; gene families involved in olfaction exhibit high diversity in different animal phyla. Insects detect volatile molecules using olfactory (OR) or ionotropic receptors (IR) and in some cases gustatory receptors (GRs). While IRs are expressed in olfactory organs across Protostomia, ORs have been hypothesized to be an adaptation to a terrestrial insect lifestyle. We investigated the olfactory system of the primary wingless bristletail Lepismachilis y-signata (Archaeognatha), the firebrat Thermobia domestica (Zygentoma) and the neopteran leaf insect Phyllium siccifolium (Phasmatodea). ORs and the olfactory coreceptor (Orco) are with very high probability lacking in Lepismachilis; in Thermobia we have identified three Orco candidates, and in Phyllium a fully developed OR/Orco-based system. We suggest that ORs did not arise as an adaptation to a terrestrial lifestyle, but evolved later in insect evolution, with Orco being present before the appearance of ORs. DOI: http://dx.doi.org/10.7554/eLife.02115.001 PMID:24670956

  12. Brief Exposure to Sensory Cues Elicits Stimulus-Nonspecific General Sensitization in an Insect

    PubMed Central

    Colson, Violaine; Party, Virginie; Renou, Michel; Anderson, Peter; Gadenne, Christophe; Marion-Poll, Frédéric; Anton, Sylvia

    2012-01-01

    The effect of repeated exposure to sensory stimuli, with or without reward is well known to induce stimulus-specific modifications of behaviour, described as different forms of learning. In recent studies we showed that a brief single pre-exposure to the female-produced sex pheromone or even a predator sound can increase the behavioural and central nervous responses to this pheromone in males of the noctuid moth Spodoptera littoralis. To investigate if this increase in sensitivity might be restricted to the pheromone system or is a form of general sensitization, we studied here if a brief pre-exposure to stimuli of different modalities can reciprocally change behavioural and physiological responses to olfactory and gustatory stimuli. Olfactory and gustatory pre-exposure and subsequent behavioural tests were carried out to reveal possible intra- and cross-modal effects. Attraction to pheromone, monitored with a locomotion compensator, increased after exposure to olfactory and gustatory stimuli. Behavioural responses to sucrose, investigated using the proboscis extension reflex, increased equally after pre-exposure to olfactory and gustatory cues. Pheromone-specific neurons in the brain and antennal gustatory neurons did, however, not change their sensitivity after sucrose exposure. The observed intra- and reciprocal cross-modal effects of pre-exposure may represent a new form of stimulus-nonspecific general sensitization originating from modifications at higher sensory processing levels. PMID:22457821

  13. Neural Correlates of Stimulus Reportability

    PubMed Central

    Hulme, Oliver J.; Friston, Karl F.; Zeki, Semir

    2012-01-01

    Most experiments on the “neural correlates of consciousness” employ stimulus reportability as an operational definition of what is consciously perceived. The interpretation of such experiments therefore depends critically on understanding the neural basis of stimulus reportability. Using a high volume of fMRI data, we investigated the neural correlates of stimulus reportability using a partial report object detection paradigm. Subjects were presented with a random array of circularly arranged disc-stimuli and were cued, after variable delays (following stimulus offset), to report the presence or absence of a disc at the cued location, using variable motor actions. By uncoupling stimulus processing, decision, and motor response, we were able to use signal detection theory to deconstruct the neural basis of stimulus reportability. We show that retinotopically specific responses in the early visual cortex correlate with stimulus processing but not decision or report; a network of parietal/temporal regions correlates with decisions but not stimulus presence, whereas classical motor regions correlate with report. These findings provide a basic framework for understanding the neural basis of stimulus reportability without the theoretical burden of presupposing a relationship between reportability and consciousness. PMID:18823251

  14. Paraneoplastic syndromes in olfactory neuroblastoma

    PubMed Central

    Gabrych, Anna; Czapiewski, Piotr; Sworczak, Krzysztof

    2015-01-01

    Olfactory neuroblastoma (ONB) is a rare malignant neoplasm of sinonasal tract, derived from olfactory epithelium. Unilateral nasal obstruction, epistaxis, sinusitis, and headaches are common symptoms. Olfactory neuroblastoma shows neuroendocrine differentiation and similarly to other neuroendocrine tumors can produce several types of peptic substances and hormones. Excess production of these substances can be responsible for different types of endocrinological paraneoplastic syndromes (PNS). Moreover, besides endocrinological, in ONB may also occur neurological PNS, caused by immune cross-reactivity between tumor and normal host tissues in the nervous system. Paraneoplastic syndromes in ONB include: syndrome of inappropriate ADH secretion (SIADH), ectopic ACTH syndrome (EAS), humoral hypercalcemia of malignancy (HHM), hypertension due to catecholamine secretion by tumor, opsoclonus-myoclonus-ataxia (OMA) and paraneoplastic cerebellar degeneration. Paraneoplastic syndromes in ONB tend to have atypical features, therefore diagnosis may be difficult. In this review, we described initial symptoms, patterns of presentation, treatment and outcome of paraneoplastic syndromes in ONB, reported in the literature. PMID:26199564

  15. High-speed odor transduction and pulse tracking by insect olfactory receptor neurons

    PubMed Central

    Szyszka, Paul; Gerkin, Richard C.; Galizia, C. Giovanni; Smith, Brian H.

    2014-01-01

    Sensory systems encode both the static quality of a stimulus (e.g., color or shape) and its kinetics (e.g., speed and direction). The limits with which stimulus kinetics can be resolved are well understood in vision, audition, and somatosensation. However, the maximum temporal resolution of olfactory systems has not been accurately determined. Here, we probe the limits of temporal resolution in insect olfaction by delivering high frequency odor pulses and measuring sensory responses in the antennae. We show that transduction times and pulse tracking capabilities of olfactory receptor neurons are faster than previously reported. Once an odorant arrives at the boundary layer of the antenna, odor transduction can occur within less than 2 ms and fluctuating odor stimuli can be resolved at frequencies more than 100 Hz. Thus, insect olfactory receptor neurons can track stimuli of very short duration, as occur when their antennae encounter narrow filaments in an odor plume. These results provide a new upper bound to the kinetics of odor tracking in insect olfactory receptor neurons and to the latency of initial transduction events in olfaction. PMID:25385618

  16. Successful acquisition of an olfactory discrimination test by Asian elephants, Elephas maximus.

    PubMed

    Arvidsson, Josefin; Amundin, Mats; Laska, Matthias

    2012-02-01

    The present study demonstrates that Asian elephants, Elephas maximus, can successfully be trained to cooperate in an olfactory discrimination test based on a food-rewarded two-alternative instrumental conditioning procedure. The animals learned the basic principle of the test within only 60 trials and readily mastered intramodal stimulus transfer tasks. Further, they were capable of distinguishing between structurally related odor stimuli and remembered the reward value of previously learned odor stimuli after 2, 4, 8, and 16 weeks of recess without any signs of forgetting. The precision and consistency of the elephants' performance in tests of odor discrimination ability and long-term odor memory demonstrate the suitability of this method for assessing olfactory function in this proboscid species. An across-species comparison of several measures of olfactory learning capabilities such as speed of initial task acquisition and ability to master intramodal stimulus transfer tasks shows that Asian elephants are at least as good in their performance as mice, rats, and dogs, and clearly superior to nonhuman primates and fur seals. The results support the notion that Asian elephants may use olfactory cues for social communication and food selection and that the sense of smell may play an important role in the control of their behavior.

  17. Olfactory epithelium in the olfactory recess: a case study in new world leaf-nosed bats.

    PubMed

    Eiting, Thomas P; Smith, Timothy D; Dumont, Elizabeth R

    2014-11-01

    The olfactory recess (OR) is a restricted space at the back of the nasal fossa in many mammals that is thought to improve olfactory function. Mammals that have an olfactory recess are usually described as keen-scented, while those that do not are typically thought of as less reliant on olfaction. However, the presence of an olfactory recess is not a binary trait. Many mammal families have members that vary substantially in the size and complexity of the olfactory recess. There is also variation in the amount of olfactory epithelium (OE) that is housed in the olfactory recess. Among New World leaf-nosed bats (family Phyllostomidae), species vary by over an order of magnitude in how much of their total OE lies within the OR. Does this variation relate to previously documented neuroanatomical proxies for olfactory reliance? Using data from 12 species of phyllostomid bats, we addressed the hypothesis that the amount of OE within the OR relates to a species' dependence on olfaction, as measured by two commonly used neuroanatomical metrics, the size of the olfactory bulb, and the number of glomeruli in the olfactory bulb, which are the first processing units within the olfactory signal cascade. We found that the percentage of OE within the OR does not relate to either measure of olfactory "ability." This suggests that olfactory reliance is not reflected in the size of the olfactory recess. We explore other roles that the olfactory recess may play.

  18. Stimulus Equivalence, Generalization, and Contextual Stimulus Control in Verbal Classes

    ERIC Educational Resources Information Center

    Sigurdardottir, Zuilma Gabriela; Mackay, Harry A.; Green, Gina

    2012-01-01

    Stimulus generalization and contextual control affect the development of equivalence classes. Experiment 1 demonstrated primary stimulus generalization from the members of trained equivalence classes. Adults were taught to match six spoken Icelandic nouns and corresponding printed words and pictures to one another in computerized three-choice…

  19. Correlations among stimuli affect stimulus matching and stimulus liking.

    PubMed

    Pimenta, Dióghenes; Tonneau, François

    2016-09-01

    Human subjects were exposed to AB, AC stimulus pairs and then to matching-to-sample tests of stimulus equivalence (B-A, C-A, B-C, C-B) or to a task in which stimulus compounds (BA, CA, BC, CB) were rated for attractiveness. Matching-to-sample tests revealed emergent B-A, C-A, B-C, and C-B choices, replicating previous results in the literature. The mean proportion of correct, emergent choices increased as a function of exposure to the AB, AC pairs. On the rating task, the liking scores of all stimulus compounds also increased as a function of exposure to the AB, AC pairs. After limited exposure to these pairs, however, the liking scores of the BC and CB compounds were negative. These findings are discussed in relation to perceptual and associative perspectives on the behavioral effects of stimulus correlations.

  20. Contextual taste cues modulate olfactory learning in C. elegans by an occasion-setting mechanism.

    PubMed

    Law, Eric; Nuttley, William M; van der Kooy, Derek

    2004-07-27

    Manipulations of context can affect learning and memory performance across species in many associative learning paradigms. Using taste cues to create distinct contexts for olfactory adaptation assays in the nematode Caenorhabditis elegans, we now show that performance in this associative learning paradigm is sensitive to context manipulations, and we investigate the mechanism(s) used for the integration of context cues in learning. One possibility is that the taste and olfactory stimuli are perceived as a combined, blended cue that the animals then associate with the unconditioned stimulus (US) in the same manner as with any other unitary conditioned stimuli (CS). Alternatively, an occasion-setting model suggests that the taste cues only define the appropriate context for olfactory memory retrieval without directly entering into the primary association. Analysis of genetic mutants demonstrated that the olfactory and context cues are sensed by distinct primary sensory neurons and that the animals' ability to use taste cues to modulate olfactory learning is independent from their ability to utilize these same taste cues for adaptation. We interpret these results as evidence for the occasion-setting mechanism in which context cues modulate primary Pavlovian association by functioning in a hierarchical manner to define the appropriate setting for memory recall.

  1. Time-course of trigeminal versus olfactory stimulation: evidence from chemosensory evoked potentials.

    PubMed

    Flohr, Elena L R; Boesveldt, Sanne; Haehner, Antje; Iannilli, Emilia; Sinding, Charlotte; Hummel, Thomas

    2015-03-01

    Habituation of responses to chemosensory signals has been explored in many ways. Strong habituation and adaptation processes can be observed at the various levels of processing. For example, with repeated exposure, amplitudes of chemosensory event-related potentials (ERP) decrease over time. However, long-term habituation has not been investigated so far and investigations of differences in habituation between trigeminal and olfactory ERPs are very rare. The present study investigated habituation over a period of approximately 80 min for two olfactory and one trigeminal stimulus, respectively. Habituation was examined analyzing the N1 and P2 amplitudes and latencies of chemosensory ERPs and intensity ratings. It was shown that amplitudes of both components - and intensity ratings - decreased from the first to the last block. Concerning ERP latencies no effects of habituation were seen. Amplitudes of trigeminal ERPs diminished faster than amplitudes of olfactory ERPs, indicating that the habituation of trigeminal ERPs is stronger than habituation of olfactory ERPs. Amplitudes of trigeminal ERPs were generally higher than amplitudes of olfactory ERPs, as it has been shown in various studies before. The results reflect relatively selective central changes in response to chemosensory stimuli over time.

  2. Response Times to Gustatory–Olfactory Flavor Mixtures: Role of Congruence

    PubMed Central

    Shepard, Timothy G.; Veldhuizen, Maria G.

    2015-01-01

    A mixture of perceptually congruent gustatory and olfactory flavorants (sucrose and citral) was previously shown to be detected faster than predicted by a model of probability summation that assumes stochastically independent processing of the individual gustatory and olfactory signals. This outcome suggests substantial integration of the signals. Does substantial integration also characterize responses to mixtures of incongruent flavorants? Here, we report simple response times (RTs) to detect brief pulses of 3 possible flavorants: monosodium glutamate, MSG (gustatory: “umami” quality), citral (olfactory: citrus quality), and a mixture of MSG and citral (gustatory–olfactory). Each stimulus (and, on a fraction of trials, water) was presented orally through a computer-operated, automated flow system, and subjects were instructed to press a button as soon as they detected any of the 3 non-water stimuli. Unlike responses previously found to the congruent mixture of sucrose and citral, responses here to the incongruent mixture of MSG and citral took significantly longer (RTs were greater) and showed lower detection rates than the values predicted by probability summation. This outcome suggests that the integration of gustatory and olfactory flavor signals is less extensive when the component flavors are perceptually incongruent rather than congruent, perhaps because incongruent flavors are less familiar. PMID:26304508

  3. Stimulus control and associative learning.

    PubMed Central

    Williams, B A

    1984-01-01

    Interest in operant research on stimulus control has declined at the same time that much interest has burgeoned in nonoperant areas. Several examples of this shift toward traditional learning theory are considered, all of which have sponsored theoretical approaches that attempt to characterize the underlying associative units. These theoretical approaches are defended on the grounds that they have generated a deeper understanding of a variety of often puzzling phenomena. My projection is that future research will be determined even more strongly by theories about the structure of associations. Particular issues for which such discussion will have major impact include (1) whether conditional stimulus control is qualitatively different than simpler forms of stimulus control, (2) whether stimulus control is organized hierarchically, and (3) the origin of categories of stimulus equivalence. PMID:6520579

  4. Hypothyroidism Affects Olfactory Evoked Potentials.

    PubMed

    Świdziński, Teodor; Linkowska-Świdzińska, Kamila; Czerniejewska-Wolska, Hanna; Wiskirska-Woźnica, Bożena; Owecki, Maciej; Głowacka, Maria Danuta; Frankowska, Anna; Łącka, Katarzyna; Glapiński, Mariusz; Maciejewska-Szaniec, Zofia; Świdziński, Piotr

    Background. Objective electrophysiological methods for investigations of the organ of smell consist in recordings of olfactory cortex responses to specific, time restricted odor stimuli. In hypothyroidism have impaired sense of smell. Material and Methods. Two groups: control of 31 healthy subjects and study group of 21 with hypothyroidism. The inclusion criterion for the study group was the TSH range from 3.54 to 110 μIU/mL. Aim. Assessment of the latency time of evoked responses from the olfactory nerve N1 and the trigeminal nerve N5 using two smells of mint and anise in hypothyroidism. Results. The smell perception in subjective olfactory tests was normal in 85% of the hypothyroid group. Differences were noticed in the objective tests. The detailed intergroup analysis of latency times of recorded cortical responses PN5 and PN1 performed by means between the groups of patients with overt clinical hypothyroidism versus subclinical hypothyroidism demonstrated a significant difference (p < 0.05) whereas no such differences were found between the control group versus subclinical hypothyroidism group (p > 0.05). Conclusion. We can conclude that registration of cortex potentials at irritation of olfactory and trigeminal nerves offers possibilities for using this method as an objective indicator of hypothyroidism severity and prognostic process factor.

  5. Hypothyroidism Affects Olfactory Evoked Potentials

    PubMed Central

    Świdziński, Teodor; Czerniejewska-Wolska, Hanna; Wiskirska-Woźnica, Bożena; Owecki, Maciej; Głowacka, Maria Danuta; Frankowska, Anna; Łącka, Katarzyna; Glapiński, Mariusz; Maciejewska-Szaniec, Zofia; Świdziński, Piotr

    2016-01-01

    Background. Objective electrophysiological methods for investigations of the organ of smell consist in recordings of olfactory cortex responses to specific, time restricted odor stimuli. In hypothyroidism have impaired sense of smell. Material and Methods. Two groups: control of 31 healthy subjects and study group of 21 with hypothyroidism. The inclusion criterion for the study group was the TSH range from 3.54 to 110 μIU/mL. Aim. Assessment of the latency time of evoked responses from the olfactory nerve N1 and the trigeminal nerve N5 using two smells of mint and anise in hypothyroidism. Results. The smell perception in subjective olfactory tests was normal in 85% of the hypothyroid group. Differences were noticed in the objective tests. The detailed intergroup analysis of latency times of recorded cortical responses PN5 and PN1 performed by means between the groups of patients with overt clinical hypothyroidism versus subclinical hypothyroidism demonstrated a significant difference (p < 0.05) whereas no such differences were found between the control group versus subclinical hypothyroidism group (p > 0.05). Conclusion. We can conclude that registration of cortex potentials at irritation of olfactory and trigeminal nerves offers possibilities for using this method as an objective indicator of hypothyroidism severity and prognostic process factor. PMID:27656655

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

    PubMed Central

    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

  7. Stimulus Structure, Discrimination, and Interference

    ERIC Educational Resources Information Center

    Runquist, Willard N.

    1975-01-01

    The general purpose of this experiment was to determine whether differences in stimulus discrimination, as determined by the MIR (missing-item recognition) test, are correlated with interference in recall, as demanded by the discriminative coding hypothesis. (Author/RK)

  8. Does iron deficiency anemia affect olfactory function?

    PubMed

    Dinc, Mehmet Emre; Dalgic, Abdullah; Ulusoy, Seckin; Dizdar, Denizhan; Develioglu, Omer; Topak, Murat

    2016-07-01

    Conclusion This study found a negative effect of IDA on olfactory function. IDA leads to a reduction in olfactory function, and decreases in hemoglobin levels result in further reduction in olfactory function. Objective This study examined the effects of iron-deficiency anemia (IDA) on olfactory function. Method The study enrolled 50 IDA patients and 50 healthy subjects. Olfactory function was evaluated using the Sniffin' Sticks olfactory test. The diagnosis of IDA was made according to World Health Organization (WHO) criteria. Results Patients with IDA had a significantly lower threshold, discrimination, and identification (TDI) value, and a lower threshold compared with the control group. However, there were no significant differences between the groups in terms of smell selectivity values.

  9. Profiling of Olfactory Receptor Gene Expression in Whole Human Olfactory Mucosa

    PubMed Central

    Tarabichi, Maxime; Gregoire, Françoise; Dumont, Jacques E.; Chatelain, Pierre

    2014-01-01

    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 found in the

  10. Olfactory neuroblastoma: A case report

    PubMed Central

    USLU, GONCA HANEDAN; CANYILMAZ, EMINE; ZENGIN, AHMET YASAR; MUNGAN, SEVDEGUL; YONEY, ADNAN; BAHADIR, OSMAN; GOCMEZ, HUSEYIN

    2015-01-01

    Olfactory neuroblastoma (ON) is a rare type of malignant neoplasm originating from the olfactory neuroepithelial cells of the nasal cavity. ON is also known as esthesioneuroblastoma or neuroendocrine carcinoma. The malignancy accounts for <3% of tumors originating in the nasal cavity. Through the nasal cavity, ON may infiltrate the sinuses, the orbit and the cranium. The tumor is characterized by a pattern of slow growth and local recurrences. Treatment options are surgical excision or surgery combined with a radiotherapy (RT) and/or chemotherapy combination treatment. The present study reports the case of a 69-year-old patient with a mass in the nasal cavity who was treated by combined surgical excision and RT. The literature for ON and the treatment of the tumor are also discussed. PMID:26788185

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

    ERIC Educational Resources Information Center

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

    2006-01-01

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

  12. Linking local circuit inhibition to olfactory behavior: a critical role for granule cells in olfactory discrimination.

    PubMed

    Strowbridge, Ben W

    2010-02-11

    In this issue of Neuron, Abraham et al. report a direct connection between inhibitory function and olfactory behavior. Using molecular methods to alter glutamate receptor subunit composition in olfactory bulb granule cells, the authors found a selective modulation in the time required for difficult, but not simple, olfactory discrimination tasks.

  13. Stimulus Equivalence, Generalization, and Contextual Stimulus Control in Verbal Classes

    PubMed Central

    Sigurðardóttir, Zuilma Gabriela; Mackay, Harry A; Green, Gina

    2012-01-01

    Stimulus generalization and contextual control affect the development of equivalence classes. Experiment 1 demonstrated primary stimulus generalization from the members of trained equivalence classes. Adults were taught to match six spoken Icelandic nouns and corresponding printed words and pictures to one another in computerized three-choice matching-to-sample tasks. Tests confirmed that six equivalence classes had formed. Without further training, plural forms of the stimuli were presented in tests for all matching performances. All participants demonstrated virtually errorless performances. In Experiment 2, classifications of the nouns used in Experiment 1 were brought under contextual control. Three nouns were feminine and three were masculine. The match-to-sample training taught participants to select a comparison of the same number as the sample (i.e., singular or plural) in the presence of contextual stimulus A regardless of noun gender. Concurrently, in the presence of contextual stimulus B, participants were taught to select a comparison of the same gender as the sample (i.e., feminine or masculine), regardless of number. Generalization was assessed using a card-sorting test. All participants eventually sorted the cards correctly into gender and number stimulus classes. When printed words used in training were replaced by their picture equivalents, participants demonstrated almost errorless performances. PMID:22754102

  14. Interglomerular Connectivity within the Canonical and GC-D/Necklace Olfactory Subsystems

    PubMed Central

    Puche, Adam C.; Munger, Steven D.

    2016-01-01

    The mammalian main olfactory system contains several subsystems that differ not only in the receptors they express and the glomerular targets they innervate within the main olfactory bulb (MOB), but also in the strategies they use to process odor information. The canonical main olfactory system employs a combinatorial coding strategy that represents odorant identity as a pattern of glomerular activity. By contrast, the "GC-D/necklace" olfactory subsystem—formed by olfactory sensory neurons expressing the receptor guanylyl cyclase GC-D and their target necklace glomeruli (NGs) encircling the caudal MOB—is critical for the detection of a small number of semiochemicals that promote the acquisition of food preferences. The formation of these socially-transmitted food preferences requires the animal to integrate information about two types of olfactory stimuli: these specialized social chemosignals and the food odors themselves. However, the neural mechanisms with which the GC-D/necklace subsystem processes this information are unclear. We used stimulus-induced increases in intrinsic fluorescence signals to map functional circuitry associated with NGs and canonical glomeruli (CGs) in the MOB. As expected, CG-associated activity spread laterally through both the glomerular and external plexiform layers associated with activated glomeruli. Activation of CGs or NGs resulted in activity spread between the two types of glomeruli; there was no evidence of preferential connectivity between individual necklace glomeruli. These results support previous anatomical findings that suggest the canonical and GC-D/necklace subsystems are functionally connected and may integrate general odor and semiochemical information in the MOB. PMID:27902696

  15. Carving Executive Control at Its Joints: Working Memory Capacity Predicts Stimulus-Stimulus, but Not Stimulus-Response, Conflict

    ERIC Educational Resources Information Center

    Meier, Matt E.; Kane, Michael J.

    2015-01-01

    Three experiments examined the relation between working memory capacity (WMC) and 2 different forms of cognitive conflict: stimulus-stimulus (S-S) and stimulus-response (S-R) interference. Our goal was to test whether WMC's relation to conflict-task performance is mediated by stimulus-identification processes (captured by S-S conflict),…

  16. Postnatal development attunes olfactory bulb mitral cells to high-frequency signaling.

    PubMed

    Yu, Yiyi; Burton, Shawn D; Tripathy, Shreejoy J; Urban, Nathaniel N

    2015-11-01

    Mitral cells (MCs) are a major class of principal neurons in the vertebrate olfactory bulb, conveying odor-evoked activity from the peripheral sensory neurons to olfactory cortex. Previous work has described the development of MC morphology and connectivity during the first few weeks of postnatal development. However, little is known about the postnatal development of MC intrinsic biophysical properties. To understand stimulus encoding in the developing olfactory bulb, we have therefore examined the development of MC intrinsic biophysical properties in acute slices from postnatal day (P)7-P35 mice. Across development, we observed systematic changes in passive membrane properties and action potential waveforms consistent with a developmental increase in sodium and potassium conductances. We further observed developmental decreases in hyperpolarization-evoked membrane potential sag and firing regularity, extending recent links between MC sag heterogeneity and firing patterns. We then applied a novel combination of statistical analyses to examine how the evolution of these intrinsic biophysical properties specifically influenced the representation of fluctuating stimuli by MCs. We found that immature MCs responded to frozen fluctuating stimuli with lower firing rates, lower spike-time reliability, and lower between-cell spike-time correlations than more mature MCs. Analysis of spike-triggered averages revealed that these changes in spike timing were driven by a developmental shift from broad integration of inputs to more selective detection of coincident inputs. Consistent with this shift, generalized linear model fits to MC firing responses demonstrated an enhanced encoding of high-frequency stimulus features by mature MCs.

  17. The Rate of Concentration Change and How It Determines the Resolving Power of Olfactory Receptor Neurons

    PubMed Central

    Tichy, Harald; Hellwig, Maria; Zopf, Lydia M.

    2016-01-01

    The response characteristics of olfactory receptor neurons (ORNs) and their corollary, the differential sensitivity and the resolving power, are fundamental to understand olfactory coding and the information extracted from a fluctuating olfactory signal. Previous work has focused on the temporal resolution of odor pulses presented for very brief periods at varying concentrations. The time course of the odor pulses as a stimulus parameter has not been considered. The present study investigated the precision of the ON and OFF ORNs on the antennae of the cockroach to discriminate increments and decrements of continuously rising and falling odor concentrations. Stimulation consisted of ramp-like upward and downward concentration changes in a trapezoid fashion. By varying ramp steepness, we examined the effect of the rate of concentration change. Both ORNs were clearly dependent on continuously rising and falling odor concentrations. As the rate of upward and downward concentration changes increases, differential sensitivity improves. Since the scatter of responses around the stimulus-response functions also increases, the resolving power for concentration increments and decrements deteriorates. Thus, the slower the rate of concentration change, the higher the precision in differentiating small concentration changes. Intuitively, the inverse relationship between the rate of concentration change and the resolving power is not surprising because accuracy requires time. A high degree of precision at slow concentration rates enables the cockroach to use information about the onset and offset slopes of odor pulses in addition to the pulse height to encode the spatial-temporal structure of turbulent odor plumes. PMID:28082912

  18. Olfactory experience shapes the evaluation of odour similarity in ants: a behavioural and computational analysis

    PubMed Central

    Perez, Margot; Nowotny, Thomas; d'Ettorre, Patrizia

    2016-01-01

    Perceptual similarity between stimuli is often assessed via generalization, the response to stimuli that are similar to the one which was previously conditioned. Although conditioning procedures are variable, studies on how this variation may affect perceptual similarity remain scarce. Here, we use a combination of behavioural and computational analyses to investigate the influence of olfactory conditioning procedures on odour generalization in ants. Insects were trained following either absolute conditioning, in which a single odour (an aldehyde) was rewarded with sucrose, or differential conditioning, in which one odour (the same aldehyde) was similarly rewarded and another odour (an aldehyde differing in carbon-chain length) was punished with quinine. The response to the trained odours and generalization to other aldehydes were assessed. We show that olfactory similarity, rather than being immutable, varies with the conditioning procedure. Compared with absolute conditioning, differential conditioning enhances olfactory discrimination. This improvement is best described by a multiplicative interaction between two independent processes, the excitatory and inhibitory generalization gradients induced by the rewarded and the punished odour, respectively. We show that olfactory similarity is dramatically shaped by an individual's perceptual experience and suggest a new hypothesis for the nature of stimulus interactions underlying experience-dependent changes in perceptual similarity. PMID:27581883

  19. Odourant dominance in olfactory mixture processing: what makes a strong odourant?

    PubMed

    Schubert, Marco; Sandoz, Jean-Christophe; Galizia, Giovanni; Giurfa, Martin

    2015-03-07

    The question of how animals process stimulus mixtures remains controversial as opposing views propose that mixtures are processed analytically, as the sum of their elements, or holistically, as unique entities different from their elements. Overshadowing is a widespread phenomenon that can help decide between these alternatives. In overshadowing, an individual trained with a binary mixture learns one element better at the expense of the other. Although element salience (learning success) has been suggested as a main explanation for overshadowing, the mechanisms underlying this phenomenon remain unclear. We studied olfactory overshadowing in honeybees to uncover the mechanisms underlying olfactory-mixture processing. We provide, to our knowledge, the most comprehensive dataset on overshadowing to date based on 90 experimental groups involving more than 2700 bees trained either with six odourants or with their resulting 15 binary mixtures. We found that bees process olfactory mixtures analytically and that salience alone cannot predict overshadowing. After normalizing learning success, we found that an unexpected feature, the generalization profile of an odourant, was determinant for overshadowing. Odourants that induced less generalization enhanced their distinctiveness and became dominant in the mixture. Our study thus uncovers features that determine odourant dominance within olfactory mixtures and allows the referring of this phenomenon to differences in neural activity both at the receptor and the central level in the insect nervous system.

  20. Disgust-Related Olfactory Processing: The Role of Gender and Trait Disgust.

    PubMed

    Schienle, Anne; Schöpf, Veronika

    2017-01-01

    For the rejection of disgusting and potentially health-threatening food, the sense of smell plays a critical role. We conducted two experiments in order to investigate the role of gender and trait disgust (the temporally stable tendency to experience disgust across different situations) on disgust-related olfactory processing. A total of 40 men and women (Study 1), as well as a group of women divided according to high versus low trait disgust (Study 2, n = 59), were compared with regard to their odor thresholds for carbon disulfide (which smells like spoiled food) and a control stimulus ( n-butanol). The stimuli were rated for experienced arousal, negative valence, and familiarity. In addition, all participants underwent the "Sniffin' Sticks" battery assessing general olfactory performance. We found that women had a lower carbon disulfide threshold and rated this odorant as more unpleasant than men. Trait disgust was neither associated with the detection of the odorant signaling spoilage, nor with general olfactory function. The latter finding questions the role of this personality trait for olfactory-driven food-rejection responses, at least for normosmic individuals.

  1. Response of the hammerhead shark olfactory epithelium to amino acid stimuli.

    PubMed

    Tricas, Timothy C; Kajiura, Stephen M; Summers, Adam P

    2009-10-01

    Sharks and rays are highly sensitive to chemical stimuli in their natural environment but several hypotheses predict that hammerhead sharks, with their expanded head and enlarged olfactory epithelium, have particularly acute olfactory systems. We used the electro-olfactogram (EOG) technique to compare the relative response of the scalloped hammerhead shark (Sphyrna lewini) olfactory epithelium to 20 proteinogenic amino acids and determine the sensitivity for 6 amino acids. At micromolar concentrations, cysteine evoked the greatest EOG response which was approximately twice as large as that of alanine. The weakest response was obtained for proline followed by aspartic acid and isoleucine. The olfactory epithelium showed adaptation to sequential stimulation, and recovery was related to the inter-stimulus time period. Estimated EOG response thresholds were in the sub-nanomolar range for both alanine (9.2 x 10(-11) M) and cysteine (8.4 x 10(-10) M) and in the micromolar range for proline and serine. These thresholds from 10(-10) to 10(-6) M for the scalloped hammerhead shark are comparable or lower than those reported for other teleost and elasmobranch species. Future work should focus on binary and more complex compounds to test for competition and cross-adaptation for different classes of peripheral receptors, and their responses to molecules found in biologically relevant stimuli.

  2. Olfactory epithelium changes in germfree mice

    PubMed Central

    François, Adrien; Grebert, Denise; Rhimi, Moez; Mariadassou, Mahendra; Naudon, Laurent; Rabot, Sylvie; Meunier, Nicolas

    2016-01-01

    Intestinal epithelium development is dramatically impaired in germfree rodents, but the consequences of the absence of microbiota have been overlooked in other epithelia. In the present study, we present the first description of the bacterial communities associated with the olfactory epithelium and explored differences in olfactory epithelium characteristics between germfree and conventional, specific pathogen-free, mice. While the anatomy of the olfactory epithelium was not significantly different, we observed a thinner olfactory cilia layer along with a decreased cellular turn-over in germfree mice. Using electro-olfactogram, we recorded the responses of olfactory sensitive neuronal populations to various odorant stimulations. We observed a global increase in the amplitude of responses to odorants in germfree mice as well as altered responses kinetics. These changes were associated with a decreased transcription of most olfactory transduction actors and of olfactory xenobiotic metabolising enzymes. Overall, we present here the first evidence that the microbiota modulates the physiology of olfactory epithelium. As olfaction is a major sensory modality for most animal species, the microbiota may have an important impact on animal physiology and behaviour through olfaction alteration. PMID:27089944

  3. Calcium signals in olfactory neurons.

    PubMed

    Tareilus, E; Noé, J; Breer, H

    1995-11-09

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

  4. Defining the Stimulus - A Memoir

    PubMed Central

    Terrace, Herbert

    2010-01-01

    The eminent psychophysicist, S. S. Stevens, once remarked that, “the basic problem of psychology was the definition of the stimulus” (Stevens, 1951, p. 46). By expanding the traditional definition of the stimulus, the study of animal learning has metamorphosed into animal cognition. The main impetus for that change was the recognition that it is often necessary to postulate a representation between the traditional S and R of learning theory. Representations allow a subject to re-present a stimulus it learned previously that is currently absent. Thus, in delayed-matching-to-sample, one has to assume that a subject responds to a representation of the sample during test if it responds correctly. Other examples, to name but a few, include concept formation, spatial memory, serial memory, learning a numerical rule, imitation and metacognition. Whereas a representation used to be regarded as a mentalistic phenomenon that was unworthy of scientific inquiry, it can now be operationally defined. To accommodate representations, the traditional discriminative stimulus has to be expanded to allow for the role of representations. The resulting composite can account for a significantly larger portion of the variance of performance measures than the exteroceptive stimulus could by itself. PMID:19969047

  5. Stimulus Effects on Local Preference: Stimulus-Response Contingencies, Stimulus-Food Pairing, and Stimulus-Food Correlation

    ERIC Educational Resources Information Center

    Davison, Michael; Baum, William M.

    2010-01-01

    Four pigeons were trained in a procedure in which concurrent-schedule food ratios changed unpredictably across seven unsignaled components after 10 food deliveries. Additional green-key stimulus presentations also occurred on the two alternatives, sometimes in the same ratio as the component food ratio, and sometimes in the inverse ratio. In eight…

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

    NASA Technical Reports Server (NTRS)

    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.

  7. Olfactory sensitivity to the pheromone, androstenone, is sexually dimorphic in the pig.

    PubMed

    Dorries, K M; Adkins-Regan, E; Halpern, B P

    1995-02-01

    Sexually dimorphic pheromone pathways have been used successfully to study insect olfactory coding. As one of the few mammalian species with an identified sex pheromone, the domestic pig (Sus scrofa) may be an ideal vertebrate species in which to examine sex differences in olfactory processing of a specific stimulus. In this experiment, androstenone and control odor detection thresholds were measured in adult male, female, and castrated male pigs. In an operant task, pigs were tested with descending concentration series of both androstenone and geraniol. All groups were equally sensitive to geraniol, but there was a sex difference in sensitivity to the odor of androstenone. Female pigs' detection threshold was a dilution fivefold lower than the threshold for intact males. Castrated males did not differ significantly from either males or females. This is the first example of a sexual dimorphism in sensitivity to a mammalian pheromone.

  8. A portable experimental apparatus for human olfactory fMRI experiments.

    PubMed

    Sezille, C; Messaoudi, B; Bertrand, A; Joussain, P; Thévenet, M; Bensafi, M

    2013-08-15

    Human olfactory perception can be measured using psychophysical tools or more complex odor generating devices systems, namely olfactometers. The present paper is aimed at presenting a new inexpensive, non-voluminous portable olfactometer adapted for human fMRI experiments. The system adjusts odorant stimulus presentation to human nasal respiration and records behavioral responses in the same experimental device. Validation by psychophysical measures and photo-ionization detection showed a linear increase in both odor intensity perception and vapor concentration as a function of odorant concentration. Further validation by brain imaging revealed neural activation in typical olfactory areas. In summary, the system represents a new low-cost, easy-use, easy-maintenance portable olfactometry tool for brain imaging, opening up new possibilities for investigating neural response to odors using event-related fMRI designs.

  9. Mushroom body extrinsic neurons in the honeybee (Apis mellifera) brain integrate context and cue values upon attentional stimulus selection.

    PubMed

    Filla, Ina; Menzel, Randolf

    2015-09-01

    Multimodal GABA-immunoreactive feedback neurons in the honeybee brain connecting the output region of the mushroom body with its input are expected to tune the input to the mushroom body in an experience-dependent way. These neurons are known to change their rate responses to learned olfactory stimuli. In this work we ask whether these neurons also transmit learned attentional effects during multisensory integration. We find that a visual context and an olfactory cue change the rate responses of these neurons after learning according to the associated values of both context and cue. The learned visual context promotes attentional response selection by enhancing olfactory stimulus valuation at both the behavioral and the neural level. During a rewarded visual context, bees reacted faster and more reliably to a rewarded odor. We interpreted this as the result of the observed enhanced neural discharge toward the odor. An unrewarded context reduced already low rate responses to the unrewarded odor. In addition to stimulus valuation, these feedback neurons generate a neural error signal after an incorrect behavioral response. This might act as a learning signal in feedback neurons. All of these effects were exclusively found in trials in which the animal prepares for a motor response that happens during attentional stimulus selection. We discuss possible implications of the results for the feedback connections of the mushroom body.

  10. Ca2+-activated K+ currents regulate odor adaptation by modulating spike encoding of olfactory receptor cells.

    PubMed Central

    Kawai, Fusao

    2002-01-01

    The olfactory system is thought to accomplish odor adaptation through the ciliary transduction machinery in olfactory receptor cells (ORCs). However, ORCs that have lost their cilia can exhibit spike frequency accommodation in which the action potential frequency decreases with time despite a steady depolarizing stimulus. This raises the possibility that somatic ionic channels in ORCs might serve for odor adaptation at the level of spike encoding, because spiking responses in ORCs encode the odor information. Here I investigate the adaptational mechanism at the somatic membrane using conventional and dynamic patch-clamp recording techniques, which enable the ciliary mechanism to be bypassed. A conditioning stimulus with an odorant-induced current markedly shifted the response range of action potentials induced by the same test stimulus to higher concentrations of the odorant, indicating odor adaptation. This effect was inhibited by charybdotoxin and iberiotoxin, Ca2+-activated K+ channel blockers, suggesting that somatic Ca2+-activated K+ currents regulate odor adaptation by modulating spike encoding. I conclude that not only the ciliary machinery but also the somatic membrane currents are crucial to odor adaptation. PMID:11916858

  11. Context-dependent olfactory learning monitored by activities of salivary neurons in cockroaches.

    PubMed

    Matsumoto, Chihiro Sato; Matsumoto, Yukihisa; Watanabe, Hidehiro; Nishino, Hiroshi; Mizunami, Makoto

    2012-01-01

    Context-dependent discrimination learning, a sophisticated form of nonelemental associative learning, has been found in many animals, including insects. The major purpose of this research is to establish a method for monitoring this form of nonelemental learning in rigidly restrained insects for investigation of underlying neural mechanisms. We report context-dependent olfactory learning (occasion-setting problem solving) of salivation, which can be monitored as activity changes of salivary neurons in immobilized cockroaches, Periplaneta americana. A group of cockroaches was trained to associate peppermint odor (conditioned stimulus, CS) with sucrose solution reward (unconditioned stimulus, US) while vanilla odor was presented alone without pairing with the US under a flickering light condition (1.0 Hz) and also trained to associate vanilla odor with sucrose reward while peppermint odor was presented alone under a steady light condition. After training, the responses of salivary neurons to the rewarded peppermint odor were significantly greater than those to the unrewarded vanilla odor under steady illumination and those to the rewarded vanilla odor was significantly greater than those to the unrewarded peppermint odor in the presence of flickering light. Similar context-dependent responses were observed in another group of cockroaches trained with the opposite stimulus arrangement. This study demonstrates context-dependent olfactory learning of salivation for the first time in any vertebrate and invertebrate species, which can be monitored by activity changes of salivary neurons in restrained cockroaches.

  12. Neuromodulation of olfactory sensitivity in the peripheral olfactory organs of the American cockroach, Periplaneta americana.

    PubMed

    Jung, Je Won; Kim, Jin-Hee; Pfeiffer, Rita; Ahn, Young-Joon; Page, Terry L; Kwon, Hyung Wook

    2013-01-01

    Olfactory sensitivity exhibits daily fluctuations. Several studies have suggested that the olfactory system in insects is modulated by both biogenic amines and neuropeptides. However, molecular and neural mechanisms underlying olfactory modulation in the periphery remain unclear since neuronal circuits regulating olfactory sensitivity have not been identified. Here, we investigated the structure and function of these signaling pathways in the peripheral olfactory system of the American cockroach, Periplaneta americana, utilizing in situ hybridization, qRT-PCR, and electrophysiological approaches. We showed that tachykinin was co-localized with the octopamine receptor in antennal neurons located near the antennal nerves. In addition, the tachykinin receptor was found to be expressed in most of the olfactory receptor neurons in antennae. Functionally, the effects of direct injection of tachykinin peptides, dsRNAs of tachykinin, tachykinin receptors, and octopamine receptors provided further support for the view that both octopamine and tachykinin modulate olfactory sensitivity. Taken together, these findings demonstrated that octopamine and tachykinin in antennal neurons are olfactory regulators in the periphery. We propose here the hypothesis that octopamine released from neurons in the brain regulates the release of tachykinin from the octopamine receptor neurons in antennae, which in turn modulates the olfactory sensitivity of olfactory receptor neurons, which house tachykinin receptors.

  13. A Closer Look at Acid-Base Olfactory Titrations

    ERIC Educational Resources Information Center

    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.

  14. 21 CFR 874.1600 - Olfactory test device.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Diagnostic Devices § 874.1600 Olfactory test device. (a) Identification. An olfactory test device is used to determine whether an olfactory loss is present. The device... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Olfactory test device. 874.1600 Section...

  15. 21 CFR 874.1600 - Olfactory test device.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Diagnostic Devices § 874.1600 Olfactory test device. (a) Identification. An olfactory test device is used to determine whether an olfactory loss is present. The device... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Olfactory test device. 874.1600 Section...

  16. Detection of Olfactory Dysfunction Using Olfactory Event Related Potentials in Young Patients with Multiple Sclerosis

    PubMed Central

    Caminiti, Fabrizia; De Salvo, Simona; De Cola, Maria Cristina; Russo, Margherita; Bramanti, Placido; Marino, Silvia; Ciurleo, Rosella

    2014-01-01

    Background Several studies reported olfactory dysfunction in patients with multiple sclerosis. The estimate of the incidence of olfactory deficits in multiple sclerosis is uncertain; this may arise from different testing methods that may be influenced by patients' response bias and clinical, demographic and cognitive features. Aims To evaluate objectively the olfactory function using Olfactory Event Related Potentials. Materials and Methods We tested the olfactory function of 30 patients with relapsing remitting multiple sclerosis (mean age of 36.03±6.96 years) and of 30 age, sex and smoking–habit matched healthy controls by using olfactory potentials. A selective and controlled stimulation of the olfactory system to elicit the olfactory event related potentials was achieved by a computer-controlled olfactometer linked directly with electroencephalograph. Relationships between olfactory potential results and patients' clinical characteristics, such as gender, disability status score, disease-modifying therapy, and disease duration, were evaluated. Results Seven of 30 patients did not show olfactory event related potentials. Sixteen of remaining 23 patients had a mean value of amplitude significantly lower than control group (p<0.01). The presence/absence of olfactory event related potentials was associated with dichotomous expanded disability status scale (p = 0.0433), as well as inversely correlated with the disease duration (r = −0.3641, p = 0.0479). Conclusion Unbiased olfactory dysfunction of different severity found in multiple sclerosis patients suggests an organic impairment which could be related to neuroinflammatory and/or neurodegenerative processes of olfactory networks, supporting the recent findings on neurophysiopathology of disease. PMID:25047369

  17. Plasticity-driven individualization of olfactory coding in mushroom body output neurons

    PubMed Central

    Hige, Toshihide; Aso, Yoshinori; Rubin, Gerald M.; Turner, Glenn C.

    2015-01-01

    Although all sensory circuits ascend to higher brain areas where stimuli are represented in sparse, stimulus-specific activity patterns, relatively little is known about sensory coding on the descending side of neural circuits, as a network converges. In insects, mushroom bodies (MBs) have been an important model system for studying sparse coding in the olfactory system1–3, where this format is important for accurate memory formation4–6. In Drosophila, it has recently been shown that the 2000 Kenyon cells (KCs) of the MB converge onto a population of only 35 MB output neurons (MBONs), that fall into 22 anatomically distinct cell types7,8. Here we provide the first comprehensive view of olfactory representations at the fourth layer of the circuit, where we find a clear transition in the principles of sensory coding. We show that MBON tuning curves are highly correlated with one another. This is in sharp contrast to the process of progressive decorrelation of tuning in the earlier layers of the circuit2,9. Instead, at the population level, odor representations are reformatted so that positive and negative correlations arise between representations of different odors. At the single-cell level, we show that uniquely identifiable MBONs display profoundly different tuning across different animals, but tuning of the same neuron across the two hemispheres of an individual fly was nearly identical. Thus, individualized coordination of tuning arises at this level of the olfactory circuit. Furthermore, we find that this individualization is an active process that requires a learning-related gene, rutabaga. Ultimately, neural circuits have to flexibly map highly stimulus-specific information in sparse layers onto a limited number of different motor outputs. The reformatting of sensory representations we observe here may mark the beginning of this sensory-motor transition in the olfactory system. PMID:26416731

  18. Preliminary Modeling and Simulation Study on Olfactory Cell Sensation

    SciTech Connect

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

    2009-05-23

    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.

  19. [Odor sensing system and olfactory display].

    PubMed

    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.

  20. Olfactory Behavioral Testing in the Adult Mouse

    PubMed Central

    M. Witt, Rochelle; M. Galligan, Meghan; R. Despinoy, Jennifer; Segal, Rosalind

    2009-01-01

    The rodent olfactory system is of increasing interest to scientists, studied, in part, in systems biology because of its stereotyped, yet accessible circuitry. In addition, this area's unique ability to generate new neurons throughout an organism's lifetime makes it an attractive system for developmental and regenerative biologists alike. Such interest necessitates a means for a quick, yet reliable assessment of olfactory function. Many tests of olfactory ability are complex, variable or not specifically designed for mice. Also, some tests are sensitive to memory deficits as well as defects in olfactory abilities, confounding obtained results. Here, we describe a simple battery of tests designed to identify defects in olfactory sensitivity and preference. First, an initial general health assessment allows for the identification of animals suitable for further testing. Second, mice are exposed to various dilutions of scents to ascertain whether there is a threshold difference. Third, mice are presented with various scents, both attractive and aversive, that allow for the assessment of olfactory preference. These simple studies should make the initial characterization of olfactory behavior accessible for labs of varied resources and expertise. PMID:19229182

  1. Olfactory behavioral testing in the adult mouse.

    PubMed

    Witt, Rochelle M; Galligan, Meghan M; Despinoy, Jennifer R; Segal, Rosalind

    2009-01-28

    The rodent olfactory system is of increasing interest to scientists, studied, in part, in systems biology because of its stereotyped, yet accessible circuitry. In addition, this area's unique ability to generate new neurons throughout an organism's lifetime makes it an attractive system for developmental and regenerative biologists alike. Such interest necessitates a means for a quick, yet reliable assessment of olfactory function. Many tests of olfactory ability are complex, variable or not specifically designed for mice. Also, some tests are sensitive to memory deficits as well as defects in olfactory abilities, confounding obtained results. Here, we describe a simple battery of tests designed to identify defects in olfactory sensitivity and preference. First, an initial general health assessment allows for the identification of animals suitable for further testing. Second, mice are exposed to various dilutions of scents to ascertain whether there is a threshold difference. Third, mice are presented with various scents, both attractive and aversive, that allow for the assessment of olfactory preference. These simple studies should make the initial characterization of olfactory behavior accessible for labs of varied resources and expertise.

  2. Information processing in the mammalian olfactory system.

    PubMed

    Lledo, Pierre-Marie; Gheusi, Gilles; Vincent, Jean-Didier

    2005-01-01

    Recently, modern neuroscience has made considerable progress in understanding how the brain perceives, discriminates, and recognizes odorant molecules. This growing knowledge took over when the sense of smell was no longer considered only as a matter for poetry or the perfume industry. Over the last decades, chemical senses captured the attention of scientists who started to investigate the different stages of olfactory pathways. Distinct fields such as genetic, biochemistry, cellular biology, neurophysiology, and behavior have contributed to provide a picture of how odor information is processed in the olfactory system as it moves from the periphery to higher areas of the brain. So far, the combination of these approaches has been most effective at the cellular level, but there are already signs, and even greater hope, that the same is gradually happening at the systems level. This review summarizes the current ideas concerning the cellular mechanisms and organizational strategies used by the olfactory system to process olfactory information. We present findings that exemplified the high degree of olfactory plasticity, with special emphasis on the first central relay of the olfactory system. Recent observations supporting the necessity of such plasticity for adult brain functions are also discussed. Due to space constraints, this review focuses mainly on the olfactory systems of vertebrates, and primarily those of mammals.

  3. Olfactory deposition of inhaled nanoparticles in humans

    PubMed Central

    Garcia, Guilherme J. M.; Schroeter, Jeffry D.; Kimbell, Julia S.

    2016-01-01

    Context Inhaled nanoparticles can migrate to the brain via the olfactory bulb, as demonstrated in experiments in several animal species. This route of exposure may be the mechanism behind the correlation between air pollution and human neurodegenerative diseases, including Alzheimer’s disease and Parkinson’s disease. Objectives This manuscript aims to (1) estimate the dose of inhaled nanoparticles that deposit in the human olfactory epithelium during nasal breathing at rest and (2) compare the olfactory dose in humans with our earlier dose estimates for rats. Materials and methods An anatomically-accurate model of the human nasal cavity was developed based on computed tomography scans. The deposition of 1–100 nm particles in the whole nasal cavity and its olfactory region were estimated via computational fluid dynamics (CFD) simulations. Our CFD methods were validated by comparing our numerical predictions for whole-nose deposition with experimental data and previous CFD studies in the literature. Results In humans, olfactory dose of inhaled nanoparticles is highest for 1–2 nm particles with approximately 1% of inhaled particles depositing in the olfactory region. As particle size grows to 100 nm, olfactory deposition decreases to 0.01% of inhaled particles. Discussion and conclusion Our results suggest that the percentage of inhaled particles that deposit in the olfactory region is lower in humans than in rats. However, olfactory dose per unit surface area is estimated to be higher in humans due to their larger minute volume. These dose estimates are important for risk assessment and dose-response studies investigating the neurotoxicity of inhaled nanoparticles. PMID:26194036

  4. Olfactory learning and memory in the disease vector mosquito Aedes aegypti

    PubMed Central

    Vinauger, Clément; Lutz, Eleanor K.; Riffell, Jeffrey A.

    2014-01-01

    Olfactory learning in blood-feeding insects, such as mosquitoes, could play an important role in host preference and disease transmission. However, standardised protocols allowing testing of their learning abilities are currently lacking, and how different olfactory stimuli are learned by these insects remains unknown. Using a Pavlovian conditioning paradigm, we trained individuals and groups of Aedes aegypti mosquitoes to associate an odorant conditioned stimulus (CS) with a blood-reinforced thermal stimulus (unconditioned stimulus; US). Results showed, first, that mosquitoes could learn the association between L-lactic acid and the US, and retained the association for at least 24 h. Second, the success of olfactory conditioning was dependent upon the CS – some odorants that elicited indifferent responses in naïve mosquitoes, such as L-lactic acid and 1-octen-3-ol, were readily learned, whereas others went from aversive to attractive after training (Z-3-hexen-1-ol) or were untrainable (β-myrcene and benzyl alcohol). Third, we examined whether mosquitoes' ability to learn could interfere with the action of the insect repellent DEET. Results demonstrated that pre-exposure and the presence of DEET in the CS reduced the aversive effects of DEET. Last, the nature of the formed memories was explored. Experiments using cold-shock treatments within the first 6 h post-training (for testing anaesthesia-resistant memory) and a protein synthesis inhibitor (cycloheximide; to disrupt the formation of long-term memory) both affected mosquitoes' performances. Together, these results show that learning is a crucial component in odour responses in A. aegypti, and provide the first evidence for the functional role of different memory traces in these responses. PMID:24737761

  5. Unraveling Cajal's view of the olfactory system

    PubMed Central

    Figueres-Oñate, María; Gutiérrez, Yolanda; López-Mascaraque, Laura

    2014-01-01

    The olfactory system has a highly regular organization of interconnected synaptic circuits from the periphery. It is therefore an excellent model for understanding general principles about how the brain processes information. Cajal revealed the basic cell types and their interconnections at the end of the XIX century. Since his original descriptions, the observation and analysis of the olfactory system and its components represents a major topic in neuroscience studies, providing important insights into the neural mechanisms. In this review, we will highlight the importance of Cajal contributions and his legacy to the actual knowledge of the olfactory system. PMID:25071462

  6. The Interglomerular Circuit Potently Inhibits Olfactory Bulb Output Neurons by Both Direct and Indirect Pathways

    PubMed Central

    Puche, Adam C.; Shipley, Michael T.

    2016-01-01

    Sensory processing shapes our perception. In mammals, odor information is encoded by combinatorial activity patterns of olfactory bulb (OB) glomeruli. Glomeruli are richly interconnected by short axon cells (SACs), which form the interglomerular circuit (IGC). It is unclear how the IGC impacts OB output to downstream neural circuits. We combined in vitro and in vivo electrophysiology with optogenetics in mice and found the following: (1) the IGC potently and monosynaptically inhibits the OB output neurons mitral/tufted cells (MTCs) by GABA release from SACs: (2) gap junction-mediated electrical coupling is strong for the SAC→MTC synapse, but negligible for the SAC→ETC synapse; (3) brief IGC-mediated inhibition is temporally prolonged by the intrinsic properties of MTCs; and (4) sniff frequency IGC activation in vivo generates persistent MTC inhibition. These findings suggest that the temporal sequence of glomerular activation by sensory input determines which stimulus features are transmitted to downstream olfactory networks and those filtered by lateral inhibition. SIGNIFICANCE STATEMENT Odor identity is encoded by combinatorial patterns of activated glomeruli, the initial signal transformation site of the olfactory system. Lateral circuit processing among activated glomeruli modulates olfactory signal transformation before transmission to higher brain centers. Using a combination of in vitro and in vivo optogenetics, this work demonstrates that interglomerular circuitry produces potent inhibition of olfactory bulb output neurons via direct chemical and electrical synapses as well as by indirect pathways. The direct inhibitory synaptic input engages mitral cell intrinsic membrane properties to generate inhibition that outlasts the initial synaptic action. PMID:27629712

  7. Understanding the Odour Spaces: A Step towards Solving Olfactory Stimulus-Percept Problem

    PubMed Central

    Kumar, Ritesh; Bhondekar, Amol P.

    2015-01-01

    Odours are highly complex, relying on hundreds of receptors, and people are known to disagree in their linguistic descriptions of smells. It is partly due to these facts that, it is very hard to map the domain of odour molecules or their structure to that of perceptual representations, a problem that has been referred to as the Structure-Odour-Relationship. We collected a number of diverse open domain databases of odour molecules having unorganised perceptual descriptors, and developed a graphical method to find the similarity between perceptual descriptors; which is intuitive and can be used to identify perceptual classes. We then separately projected the physico-chemical and perceptual features of these molecules in a non-linear dimension and clustered the similar molecules. We found a significant overlap between the spatial positioning of the clustered molecules in the physico-chemical and perceptual spaces. We also developed a statistical method of predicting the perceptual qualities of a novel molecule using its physico-chemical properties with high receiver operating characteristics(ROC). PMID:26484763

  8. Economic Stimulus: Issues and Policies

    DTIC Science & Technology

    2009-01-16

    that “fiscal action could be helpful in principle , as fiscal and monetary stimulus together may provide broader support for the economy than monetary...have sought to contain damages spilling over from housing and financial markets to the broader economy , including monetary policy, which is the...including leaving the government holding large amounts of mortgage debt. With the worsening performance of the economy , congressional leaders and

  9. Discriminative Stimulus Effects of Psychostimulants.

    PubMed

    Berquist, Michael D; Fantegrossi, William E

    2017-03-25

    Numerous drugs elicit locomotor stimulant effects at appropriate doses; however, we typically reserve the term psychostimulant to refer to drugs with affinity for monoamine reuptake transporters. This chapter comprises select experiments that have characterized the discriminative stimulus effects of psychostimulants using drug discrimination procedures. The substitution profiles of psychostimulants in laboratory rodents are generally consistent with those observed in human and nonhuman primate drug discrimination experiments. Notably, two major classes of psychostimulants can be distinguished as those that function as passive monoamine reuptake inhibitors (such as cocaine) and those that function as substrates for monoamine transporters and stimulate monoamine release (such as the amphetamines). Nevertheless, the discriminative stimulus effects of both classes of psychostimulant are quite similar, and drugs from different classes will substitute for one another. Most importantly, for both the cocaine-like and amphetamine-like psychostimulants, dopaminergic mechanisms most saliently determine discriminative stimulus effects, but these effects can be modulated by alterations in noradrenergic and serotonergic neurotransmission as well. Thusly, the drug discrimination assay is useful for characterizing the interoceptive effects of psychostimulants and determining the mechanisms that contribute to their subjective effects in humans.

  10. Pharmacology of mammalian olfactory receptors.

    PubMed

    Smith, Richard S; Peterlin, Zita; Araneda, Ricardo C

    2013-01-01

    Mammalian species have evolved a large and diverse number of odorant receptors (ORs). These proteins comprise the largest family of G-protein-coupled receptors (GPCRs) known, amounting to ~1,000-different receptors in the rodent. From the perspective of olfactory coding, the availability of such a vast number of chemosensory receptors poses several fascinating questions; in addition, such a large repertoire provides an attractive biological model to study ligand-receptor interactions. The limited functional expression of these receptors in heterologous systems, however, has greatly hampered attempts to deorphanize them. We have employed a successful approach that combines electrophysiological and imaging techniques to analyze the response profiles of single sensory neurons. Our approach has enabled us to characterize the "odor space" of a population of native aldehyde receptors and the molecular range of a genetically engineered receptor, OR-I7.

  11. Modeling Olfactory Bulb Evolution through Primate Phylogeny

    PubMed Central

    Heritage, Steven

    2014-01-01

    Adaptive characterizations of primates have usually included a reduction in olfactory sensitivity. However, this inference of derivation and directionality assumes an ancestral state of olfaction, usually by comparison to a group of extant non-primate mammals. Thus, the accuracy of the inference depends on the assumed ancestral state. Here I present a phylogenetic model of continuous trait evolution that reconstructs olfactory bulb volumes for ancestral nodes of primates and mammal outgroups. Parent-daughter comparisons suggest that, relative to the ancestral euarchontan, the crown-primate node is plesiomorphic and that derived reduction in olfactory sensitivity is an attribute of the haplorhine lineage. The model also suggests a derived increase in olfactory sensitivity at the strepsirrhine node. This oppositional diversification of the strepsirrhine and haplorhine lineages from an intermediate and non-derived ancestor is inconsistent with a characterization of graded reduction through primate evolution. PMID:25426851

  12. The Pig Olfactory Brain: A Primer

    PubMed Central

    Feldman, Sanford; Osterberg, Stephen K.

    2016-01-01

    Despite the fact that pigs are reputed to have excellent olfactory abilities, few studies have examined regions of the pig brain involved in the sense of smell. The present study provides an overview of the olfactory bulb, anterior olfactory nucleus, and piriform cortex of adult pigs using several approaches. Nissl, myelin, and Golgi stains were used to produce a general overview of the organization of the regions and confocal microscopy was employed to examine 1) projection neurons, 2) GABAergic local circuit neurons that express somatostatin, parvalbumin, vasoactive intestinal polypeptide, or calretinin, 3) neuromodulatory fibers (cholinergic and serotonergic), and 4) glia (astrocytes and microglia). The findings revealed that pig olfactory structures are quite large, highly organized and follow the general patterns observed in mammals. PMID:26936231

  13. A multisensory network for olfactory processing

    PubMed Central

    Maier, Joost X.; Blankenship, Meredith L.; Li, Jennifer X.; Katz, Donald B.

    2015-01-01

    Summary Primary gustatory cortex (GC) is connected (both mono- and poly-synaptically) to primary olfactory (piriform) cortex (PC)—connections that might be hypothesized to underlie the construction of a “flavor” percept when both gustatory and olfactory stimuli are present. Here, we use multi-site electrophysiology and optical inhibition of GC neurons (GCx, produced via infection with ArchT) to demonstrate that, indeed, during gustatory stimulation, taste-selective information is transmitted from GC to PC. We go on to show that these connections impact olfactory processing even in the absence of gustatory stimulation: GCx alters PC responses to olfactory stimuli presented alone, enhancing some and eliminating others, despite leaving the path from nasal epithelium to PC intact. Finally, we show the functional importance of this latter phenomenon, demonstrating that GCx renders rats unable to properly recognize odor stimuli. This sequence of findings suggests that sensory processing may be more intrinsically integrative than previously thought. PMID:26441351

  14. Dimorphic olfactory lobes in the arthropoda.

    PubMed

    Strausfeld, Nicholas; Reisenman, Carolina E

    2009-07-01

    Specialized olfactory lobe glomeruli relating to sexual or caste differences have been observed in at least five orders of insects, suggesting an early appearance of this trait in insect evolution. Dimorphism is not limited to nocturnal species, but occurs even in insects that are known to use vision for courtship. Other than a single description, there is no evidence for similar structures occurring in the Crustacea, suggesting that the evolution of dimorphic olfactory systems may typify terrestrial arthropods.

  15. Cladistic Analysis of Olfactory and Vomeronasal Systems

    PubMed Central

    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

  16. Cladistic analysis of olfactory and vomeronasal systems.

    PubMed

    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.

  17. Investigating the roles of odor-evoked oscillations in information processing in the turtle olfactory bulb

    NASA Astrophysics Data System (ADS)

    Kim, Soyoun

    It has been earlier established that presentation of an odorant stimulus to the turtle evokes specific spatio-temporal responses in the olfactory bulb. This response includes three distinct oscillatory patterns (rostral, middle and caudal) that have different spatial (locations and scopes) and temporal (frequencies and delay from the odorant onset) properties. In this thesis we investigate, using modeling and experimental approaches; the mechanisms of formation and the role of the oscillatory patterning in the turtle olfactory bulb. We have built a computational model that incorporates the basic anatomy and neurophysiology of the olfactory bulb to investigate how the observed patterns relate to activity of individual neurons and what roles they could play in olfactory information processing. We show that three basic anatomical/physiological properties of the olfactory network underlie formation of a temporal sequence of simultaneous activations of glomerular modules: fast synaptic inhibition between populations of excitatory and inhibitory cells, slow self-inhibition observed on excitatory cells; and input strength. The model suggests that the role of oscillations is to organize the neural activity in a temporal sequence which groups the activation of glomerular modules based on the input strength similarity. We show that this type of code explains particularly well the experimental findings reported also by other groups, showing that temporal patterning may mediate discrimination of similar odorants. Furthermore, we showed that within our model, feedback from cortical regions of the brain could modulate oscillatory patterning and provide mechanisms to generate experimentally observed period doubling in one of the oscillations. This requires the cortical processing to act as a type of coincidence modulator and provide functional coupling between excitatory modules that is absent in the bulbar network. This hypothesis is partially supported by our experiments that

  18. Olfactory processing in a changing brain.

    PubMed

    Lledo, Pierre-Marie; Gheusi, Gilles

    2003-09-15

    The perception of odorant molecules provides the essential information that allows animals to explore their surrounding. We describe here how the external world of scents may sculpt the activity of the first central relay of the olfactory system, i.e., the olfactory bulb. This structure is one of the few brain areas to continuously replace one of its neuronal populations: the local GABAergic interneurons. How the newly generated neurons integrate into a pre-existing neural network and how basic olfactory functions are maintained when a large percentage of neurons are subjected to continuous renewal, are important questions that have recently received new insights. Furthermore, we shall see how the adult neurogenesis is specifically subjected to experience-dependent modulation. In particular, we shall describe the sensitivity of the bulbar neurogenesis to the activity level of sensory inputs from the olfactory epithelium and, in turn, how this neurogenesis may adjust the neural network functioning to optimize odor information processing. Finally, we shall discuss the behavioral consequences of the bulbar neurogenesis and how it may be appropriate for the sense of smell. By maintaining a constitutive turnover of bulbar interneurons subjected to modulation by environmental cues, we propose that adult ongoing neurogenesis in the olfactory bulb is associated with improved olfactory memory. These recent findings not only provide new fuel for the molecular and cellular bases of sensory perception but should also shed light onto cellular bases of learning and memory.

  19. A new dopaminergic nigro-olfactory projection.

    PubMed

    Höglinger, Günter U; Alvarez-Fischer, Daniel; Arias-Carrión, Oscar; Djufri, Miriam; Windolph, Andrea; Keber, Ursula; Borta, Andreas; Ries, Vincent; Schwarting, Rainer K W; Scheller, Dieter; Oertel, Wolfgang H

    2015-09-01

    Parkinson disease (PD) is a neurodegenerative disorder characterized by massive loss of midbrain dopaminergic neurons. Whereas onset of motor impairments reflects a rather advanced stage of the disorder, hyposmia often marks the beginning of the disease. Little is known about the role of the nigro-striatal system in olfaction under physiological conditions and the anatomical basis of hyposmia in PD. Yet, the early occurrence of olfactory dysfunction implies that pathogens such as environmental toxins could incite the disease via the olfactory system. In the present study, we demonstrate a dopaminergic innervation from neurons in the substantia nigra to the olfactory bulb by axonal tracing studies. Injection of two dopaminergic neurotoxins-1-methyl-4-phenylpyridinium and 6-hydroxydopamine-into the olfactory bulb induced a decrease in the number of dopaminergic neurons in the substantia nigra. In turn, ablation of the nigral projection led to impaired olfactory perception. Hyposmia following dopaminergic deafferentation was reversed by treatment with the D1/D2/D3 dopamine receptor agonist rotigotine. Hence, we demonstrate for the first time the existence of a direct dopaminergic projection into the olfactory bulb and identify its origin in the substantia nigra in rats. These observations may provide a neuroanatomical basis for invasion of environmental toxins into the basal ganglia and for hyposmia as frequent symptom in PD.

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

    PubMed Central

    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

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

    PubMed

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

    2016-06-28

    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.

  2. Responses of mitral/tufted cells to orthodromic and antidromic electrical stimulation in the olfactory bulb of the tiger salamander.

    PubMed

    Hamilton, K A; Kauer, J S

    1988-06-01

    1. Responses evoked by electrical stimulation of the olfactory nerve and olfactory tracts were analyzed in 46 output cells of the salamander olfactory bulb, in vivo. Labeling of several cells with horseradish peroxidase indicated that they were mitral and/or tufted neurons. The responses contained reproducible sequences of depolarizing and hyperpolarizing potentials, which changed with increases in stimulus intensity. 2. Stimulation of the nerve with intensities subthreshold for evoking spikes in the recorded cell resulted in a small depolarization followed by a period of hyperpolarization, during which spontaneous spikes were suppressed. With suprathreshold stimulus intensities, a single spike or often a burst of spikes was evoked, followed by a complex prolonged hyperpolarization. When full spikes were blocked by injecting hyperpolarizing current through the recording electrode, an excitatory postsynaptic potential (EPSP) with two major components and sometimes a fast prepotential were observed at the beginning of the response. Amplitudes of the EPSP and hyperpolarization increased with graded increases in stimulus intensity. In tests with paired stimulus volleys, spike generation was inhibited for at least 1 s and often for several seconds during the hyperpolarization. 3. Stimulation of the tracts with intensities subthreshold for evoking spikes in the recorded cell resulted in a complex prolonged hyperpolarization. With suprathreshold stimulus intensities, a single spike was evoked, followed by a similar period of hyperpolarization. When full spikes were blocked by injecting hyperpolarizing current through the recording electrode, a small antidromic spike, presumably generated in the axon or initial segment, was often observed. Amplitude of the hyperpolarization increased with graded increases in stimulus intensity. In tests with paired volleys, generation of a full antidromic spike was inhibited for a period that usually began 20-30 ms, following the spike

  3. Lectin binding to olfactory system in a shark, Scyliorhinus canicula.

    PubMed

    Franceschini, V; Ciani, F

    1993-01-01

    Lectin histochemical studies were performed on the olfactory system of Scyliorhinus canicula to identify specific glycoconjugates on the cell surface of primary olfactory neurons. The olfactory receptor cells, the olfactory nerve fibers and their terminals in the bulbs were labelled with SBA, BSA-I and BSA-I-B4. The lectin staining patterns indicate that the membranes of small-spotted catshark olfactory neurons had glycoproteins with alpha-galactose residues. This carbohydrate moiety could be related to modulation of the cell-cell interactions in the olfactory system.

  4. Olfactory imprinting is correlated with changes in gene expression in the olfactory epithelia of the zebrafish.

    PubMed

    Harden, Maegan V; Newton, Lucy A; Lloyd, Russell C; Whitlock, Kathleen E

    2006-11-01

    Odors experienced as juveniles can have significant effects on the behavior of mature organisms. A dramatic example of this occurs in salmon, where the odors experienced by developing fish determine the river to which they return as adults. Further examples of olfactory memories are found in many animals including vertebrates and invertebrates. Yet, the cellular and molecular bases underlying the formation of olfactory memory are poorly understood. We have devised a series of experiments to determine whether zebrafish can form olfactory memories much like those observed in salmonids. Here we show for the first time that zebrafish form and retain olfactory memories of an artificial odorant, phenylethyl alcohol (PEA), experienced as juveniles. Furthermore, we demonstrate that exposure to PEA results in changes in gene expression within the olfactory sensory system. These changes are evident by in situ hybridization in the olfactory epithelium of the developing zebrafish. Strikingly, our analysis by in situ hybridization demonstrates that the transcription factor, otx2, is up regulated in the olfactory sensory epithelia in response to PEA. This increase is evident at 2-3 days postfertilization and is maintained in the adult animals. We propose that the changes in otx2 gene expression are manifest as an increase in the number of neuronal precursors in the cells olfactory epithelium of the odor-exposed fish. Thus, our results reveal a role for the environment in controlling gene expression in the developing peripheral nervous system.

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

    ERIC Educational Resources Information Center

    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…

  6. The location of olfactory receptors within olfactory epithelium is independent of odorant volatility and solubility

    PubMed Central

    2011-01-01

    Background Our objective was to study the pattern of olfactory receptor expression within the dorsal and ventral regions of the mouse olfactory epithelium. We hypothesized that olfactory receptors were distributed based on the chemical properties of their ligands: e.g. receptors for polar, hydrophilic and weakly volatile odorants would be present in the dorsal region of olfactory epithelium; while receptors for non-polar, more volatile odorants would be distributed to the ventral region. To test our hypothesis, we used micro-transplantation of cilia-enriched plasma membranes derived from dorsal or ventral regions of the olfactory epithelium into Xenopus oocytes for electrophysiological characterization against a panel of 100 odorants. Findings Odorants detected by ORs from the dorsal and ventral regions showed overlap in volatility and water solubility. We did not find evidence for a correlation between the solubility and volatility of odorants and the functional expression of olfactory receptors in the dorsal or ventral region of the olfactory epithelia. Conclusions No simple clustering or relationship between chemical properties of odorants could be associated with the different regions of the olfactory epithelium. These results suggest that the location of ORs within the epithelium is not organized based on the physico-chemical properties of their ligands. PMID:21548958

  7. Damage to Olfactory Progenitor Cells Is Involved in Cigarette Smoke-Induced Olfactory Dysfunction in Mice.

    PubMed

    Ueha, Rumi; Ueha, Satoshi; Kondo, Kenji; Sakamoto, Takashi; Kikuta, Shu; Kanaya, Kaori; Nishijima, Hironobu; Matsushima, Kouji; Yamasoba, Tatsuya

    2016-03-01

    Exposure to cigarette smoke is a major cause of olfactory dysfunction. However, the underlying mechanisms by which cigarette smoke interferes with the highly regenerative olfactory nerve system remain unclear. To investigate whether cigarette smoke induces olfactory dysfunction by disrupting cell proliferation and cell survival in the olfactory epithelium (OE), we developed a mouse model of smoking that involved intranasal administration of a cigarette smoke solution (CSS). Immunohistological analyses and behavioral testing showed that CSS administration during a period of 24 days reduced the number of olfactory marker protein-positive mature olfactory receptor neurons (ORNs) in the OE and induced olfactory dysfunction. These changes coincided with a reduction in the number of SOX2(+) ORN progenitors and Ki-67(+) proliferating cells in the basal layer of the OE, an increase in the number of caspase-3(+) apoptotic cells, and an increase in the expression of mRNA for the inflammatory cytokines IL-1β and IL-6. Notably, the proliferating ORN progenitor population recovered after cessation of treatment with CSS, resulting in the subsequent restoration of mature ORN numbers and olfaction. These results suggest that SOX2(+) ORN progenitors are targets of CSS-induced impairment of the OE, and that by damaging the ORN progenitor population and increasing ORN death, CSS exposure eventually overwhelms the regenerative capacity of the epithelium, resulting in reduced numbers of mature ORNs and olfactory dysfunction.

  8. Stimulus conflict triggers behavioral avoidance.

    PubMed

    Dignath, David; Eder, Andreas B

    2015-12-01

    According to a recent extension of the conflict-monitoring theory, conflict between two competing response tendencies is registered as an aversive event and triggers a motivation to avoid the source of conflict. In the present study, we tested this assumption. Over five experiments, we examined whether conflict is associated with an avoidance motivation and whether stimulus conflict or response conflict triggers an avoidance tendency. Participants first performed a color Stroop task. In a subsequent motivation test, participants responded to Stroop stimuli with approach- and avoidance-related lever movements. These results showed that Stroop-conflict stimuli increased the frequency of avoidance responses in a free-choice motivation test, and also increased the speed of avoidance relative to approach responses in a forced-choice test. High and low proportions of response conflict in the Stroop task had no effect on avoidance in the motivation test. Avoidance of conflict was, however, obtained even with new conflict stimuli that had not been presented before in a Stroop task, and when the Stroop task was replaced with an unrelated filler task. Taken together, these results suggest that stimulus conflict is sufficient to trigger avoidance.

  9. Connectivity of the amygdala, piriform, and orbitofrontal cortex during olfactory stimulation: a functional MRI study.

    PubMed

    Nigri, Anna; Ferraro, Stefania; D'Incerti, Ludovico; Critchley, Hugo D; Bruzzone, Maria Grazia; Minati, Ludovico

    2013-03-06

    The majority of existing functional MRI studies on olfactory perception have addressed the relationship between stimulus features and the intensity of activity in separate regions considered in isolation. However, anatomical studies as well as neurophysiological recordings in rats and insects suggest that odor features may also be represented in a sparse manner through the simultaneous activity of multiple cortical areas interacting as a network. Here, we aimed to map the interdependence of neural activity among regions of the human brain, representing functional connectivity, during passive smelling. Seventeen healthy participants were scanned while performing a blocked-design task alternating exposure to two unpleasant odorants and breathing fresh air. High efferent connectivity was detected for the piriform cortex and the amygdala bilaterally. By contrast, the medial orbitofrontal cortex was characterized by high afferent connectivity, notably in the absence of an overall change in the intensity of hemodynamic activity during olfactory stimulation. Our results suggest that, even in the context of an elementary task, information on olfactory stimuli is scattered by the amygdala and piriform cortex onto an anatomically sparse representation and then gathered and integrated in the medial orbitofrontal cortex.

  10. Successful acquisition of an olfactory discrimination paradigm by South African fur seals, Arctocephalus pusillus.

    PubMed

    Laska, Matthias; Svelander, Madeleine; Amundin, Mats

    2008-03-18

    The present study demonstrates that South African fur seals, Arctocephalus pusillus, can successfully be trained to discriminate between objects on the basis of odor cues. Using a task based on a food-rewarded two-choice discrimination of simultaneously presented odor stimuli the animals acquired the basic operant conditioning paradigm within 480 to 880 stimulus contacts. Moreover, the fur seals could readily transfer to new S+ and S- stimuli, were capable of distinguishing between fish- and non-fish odors as well as between two fish odors, and were able to remember the reward value of previously learned odor stimuli even after 2- and 15-week breaks. The precision and consistency of the fur seals' performance in tests of discrimination ability and memory demonstrate the suitability of this paradigm for assessing olfactory function in this pinniped. An across-species comparison of several measures of olfactory learning capabilities such as speed of initial task acquisition and ability to master transfer tasks shows that A. pusillus is similar in performance to non-human primates, but inferior to rodents such as mice and rats. The results support the assumption that fur seals may use olfactory cues for social communication and food selection and that the sense of smell may play an hitherto underestimated role in the control of their behavior.

  11. Insect-like olfactory adaptations in the terrestrial giant robber crab.

    PubMed

    Stensmyr, Marcus C; Erland, Susanne; Hallberg, Eric; Wallén, Rita; Greenaway, Peter; Hansson, Bill S

    2005-01-26

    The robber crab (Birgus latro), also known as the coconut crab, is the world's largest land-living arthropod, with a weight reaching 4 kg and a length of over half a meter. Apart from the marine larval stage, this crab is fully terrestrial, and will actually drown if submerged in water. A transition from sea to land raises dramatically new demands on the sensory equipment of an animal. In olfaction, the stimulus changes from hydrophilic molecules in aqueous solution to mainly hydrophobic in the gaseous phase. The olfactory system of land crabs thus represents an excellent opportunity for investigating the effects of the transition from sea to land. Have land crabs come to the same solutions as other terrestrial animals, or is their olfactory sense characterized by unique innovations? Here, we show that the robber crab has evolved an olfactory sense with a high degree of resemblance to the insect system. The similarities extend to physiological, behavioral, and morphological characters. The insect nose of the robber crab is a striking example of convergent evolution and nicely illustrates how similar selection pressures result in similar adaptation.

  12. Microanatomy and surgical relevance of the olfactory cistern.

    PubMed

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

    2008-01-01

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

  13. Odour aversion after olfactory conditioning of the sting extension reflex in honeybees.

    PubMed

    Carcaud, Julie; Roussel, Edith; Giurfa, Martin; Sandoz, Jean-Christophe

    2009-03-01

    In Pavlovian conditioning, an originally neutral stimulus (conditioned stimulus or CS) gains control over an animal's reflex after its association with a biologically relevant stimulus (unconditioned stimulus or US). As a consequence, a conditioned response is emitted by the animal upon further CS presentations. In such a situation, the subject exhibits a reflex response, so that whether the CS thereby acquires a positive or a negative value for the animal is difficult to assess. In honeybees, Apis mellifera, an odour (CS) can be associated either with sucrose solution (US) in the appetitive conditioning of the proboscis extension reflex (PER), or with an electric shock (US) in the aversive conditioning of the sting extension reflex (SER). The term ;aversive' may not apply to the latter as bees do not suppress SER as a consequence of learning but, on the contrary, start emitting SER to the CS. To determine whether the CS acquires a positive or a negative value in these conditioning forms, we compared the orientation behaviour of freely walking honeybees in an olfactory-cued Y-maze after training them with an odour-sucrose association (PER conditioning) or an odour-shock association (SER conditioning). We show that the same odours can acquire either a positive value when associated to sucrose, or a negative value when associated to an electric shock, as bees respectively approach or avoid the CS in the Y-maze. Importantly, these results clearly establish the aversive nature of SER conditioning in honeybees.

  14. Emergent identity but not symmetry following successive olfactory discrimination training in rats.

    PubMed

    Prichard, Ashley; Panoz-Brown, Danielle; Bruce, Katherine; Galizio, Mark

    2015-09-01

    The search for symmetry in nonhuman subjects has been successful in recent studies in pigeons (e.g., Urcuioli, 2008). The key to these successes has been the use of successive discrimination procedures and combined training on identity, as well as arbitrary, baseline relations. The present study was an effort to extend the findings and theoretical analysis developed by Urcuioli and his colleagues to rats using olfactory rather than visual stimuli. Experiment 1 was a systematic replication of Urcuioli's (2008) demonstration of symmetry in pigeons. Rats were exposed to unreinforced symmetry probes following training with two arbitrary and four identity conditional discriminations. Response rates on symmetry probe trials were low and provided little evidence for emergent symmetry in any of the seven rats tested. In Experiment 2, a separate group of six rats was trained on four identity relations and was then exposed to probe trials with four novel odor stimuli. Response rates were high on identity probe trials, and low on nonmatching probe trials. The similar patterns of responding on baseline and probe trials that were shown by most rats provided a demonstration of generalized identity matching. These findings suggest that the development of stimulus control topographies in rats with olfactory stimuli may differ from those that emerge in pigeons with visual stimuli. Urcuioli's (2008) theory has been highly successful in predicting conditions necessary for stimulus class formation in pigeons, but may not be sufficient to fully understand determinants of emergent behaviors in other nonhuman species.

  15. Honey Bees Modulate Their Olfactory Learning in the Presence of Hornet Predators and Alarm Component

    PubMed Central

    Wang, Zhengwei; Qu, Yufeng; Dong, Shihao; Wen, Ping; Li, Jianjun; Tan, Ken; Menzel, Randolf

    2016-01-01

    In Southeast Asia the native honey bee species Apis cerana is often attacked by hornets (Vespa velutina), mainly in the period from April to November. During the co-evolution of these two species honey bees have developed several strategies to defend themselves such as learning the odors of hornets and releasing alarm components to inform other mates. However, so far little is known about whether and how honey bees modulate their olfactory learning in the presence of the hornet predator and alarm components of honey bee itself. In the present study, we test for associative olfactory learning of A. cerana in the presence of predator odors, the alarm pheromone component isopentyl acetate (IPA), or a floral odor (hexanal) as a control. The results show that bees can detect live hornet odors, that there is almost no association between the innately aversive hornet odor and the appetitive stimulus sucrose, and that IPA is less well associated with an appetitive stimulus when compared with a floral odor. In order to imitate natural conditions, e.g. when bees are foraging on flowers and a predator shows up, or alarm pheromone is released by a captured mate, we tested combinations of the hornet odor and floral odor, or IPA and floral odor. Both of these combinations led to reduced learning scores. This study aims to contribute to a better understanding of the prey-predator system between A. cerana and V. velutina. PMID:26919132

  16. EMERGENT IDENTITY BUT NOT SYMMETRY FOLLOWING SUCCESSIVE OLFACTORY DISCRIMINATION TRAINING IN RATS

    PubMed Central

    Prichard, Ashley; Panoz-Brown, Danielle; Bruce, Katherine; Galizio, Mark

    2016-01-01

    The search for symmetry in nonhuman subjects has been successful in recent studies in pigeons (e.g., Urcuioli, 2008). The key to these successes has been the use of successive discrimination procedures and combined training on identity, as well as arbitrary, baseline relations. The present study was an effort to extend the findings and theoretical analysis developed by Urcuioli and his colleagues to rats using olfactory rather than visual stimuli. Experiment 1 was a systematic replication of Urcuioli’s (2008) demonstration of symmetry in pigeons. Rats were exposed to unreinforced symmetry probes following training with two arbitrary and four identity conditional discriminations. Response rates on symmetry probe trials were low and provided little evidence for emergent symmetry in any of the seven rats tested. In Experiment 2, a separate group of six rats was trained on four identity relations and was then exposed to probe trials with four novel odor stimuli. Response rates were high on identity probe trials, and low on nonmatching probe trials. The similar patterns of responding on baseline and probe trials that were shown by most rats provided a demonstration of generalized identity matching. These findings suggest that the development of stimulus control topographies in rats with olfactory stimuli may differ from those that emerge in pigeons with visual stimuli. Urcuioli’s (2008) theory has been highly successful in predicting conditions necessary for stimulus class formation in pigeons, but may not be sufficient to fully understand determinants of emergent behaviors in other nonhuman species. PMID:26377436

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

    NASA Astrophysics Data System (ADS)

    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.

  18. Honey Bees Modulate Their Olfactory Learning in the Presence of Hornet Predators and Alarm Component.

    PubMed

    Wang, Zhengwei; Qu, Yufeng; Dong, Shihao; Wen, Ping; Li, Jianjun; Tan, Ken; Menzel, Randolf

    2016-01-01

    In Southeast Asia the native honey bee species Apis cerana is often attacked by hornets (Vespa velutina), mainly in the period from April to November. During the co-evolution of these two species honey bees have developed several strategies to defend themselves such as learning the odors of hornets and releasing alarm components to inform other mates. However, so far little is known about whether and how honey bees modulate their olfactory learning in the presence of the hornet predator and alarm components of honey bee itself. In the present study, we test for associative olfactory learning of A. cerana in the presence of predator odors, the alarm pheromone component isopentyl acetate (IPA), or a floral odor (hexanal) as a control. The results show that bees can detect live hornet odors, that there is almost no association between the innately aversive hornet odor and the appetitive stimulus sucrose, and that IPA is less well associated with an appetitive stimulus when compared with a floral odor. In order to imitate natural conditions, e.g. when bees are foraging on flowers and a predator shows up, or alarm pheromone is released by a captured mate, we tested combinations of the hornet odor and floral odor, or IPA and floral odor. Both of these combinations led to reduced learning scores. This study aims to contribute to a better understanding of the prey-predator system between A. cerana and V. velutina.

  19. Using Intrinsic Flavoprotein and NAD(P)H Imaging to Map Functional Circuitry in the Main Olfactory Bulb

    PubMed Central

    Puche, Adam C.; Munger, Steven D.

    2016-01-01

    Neurons exhibit strong coupling of electrochemical and metabolic activity. Increases in intrinsic fluorescence from either oxidized flavoproteins or reduced nicotinamide adenine dinucleotide (phosphate) [NAD(P)H] in the mitochondria have been used as an indicator of neuronal activity for the functional mapping of neural circuits. However, this technique has not been used to investigate the flow of olfactory information within the circuitry of the main olfactory bulb (MOB). We found that intrinsic flavoprotein fluorescence signals induced by electrical stimulation of single glomeruli displayed biphasic responses within both the glomerular (GL) and external plexiform layers (EPL) of the MOB. Pharmacological blockers of mitochondrial activity, voltage-gated Na+ channels, or ionotropic glutamate receptors abolished stimulus-dependent flavoprotein responses. Blockade of GABAA receptors enhanced the amplitude and spatiotemporal spread of the flavoprotein signals, indicating an important role for inhibitory neurotransmission in shaping the spread of neural activity in the MOB. Stimulus-dependent spread of fluorescence across the GL and EPL displayed a spatial distribution consistent with that of individual glomerular microcircuits mapped by neuroanatomic tract tracing. These findings demonstrated the feasibility of intrinsic fluorescence imaging in the olfactory systems and provided a new tool to examine the functional circuitry of the MOB. PMID:27902689

  20. An Olfactory Indicator for Acid-Base Titrations.

    ERIC Educational Resources Information Center

    Flair, Mark N.; Setzer, William N.

    1990-01-01

    The use of an olfactory acid-base indicator in titrations for visually impaired students is discussed. Potential olfactory indicators include eugenol, thymol, vanillin, and thiophenol. Titrations performed with each indicator with eugenol proved to be successful. (KR)

  1. Olfactory coding in the honeybee lateral horn.

    PubMed

    Roussel, Edith; Carcaud, Julie; Combe, Maud; Giurfa, Martin; Sandoz, Jean-Christophe

    2014-03-03

    Olfactory systems dynamically encode odor information in the nervous system. Insects constitute a well-established model for the study of the neural processes underlying olfactory perception. In insects, odors are detected by sensory neurons located in the antennae, whose axons project to a primary processing center, the antennal lobe. There, the olfactory message is reshaped and further conveyed to higher-order centers, the mushroom bodies and the lateral horn. Previous work has intensively analyzed the principles of olfactory processing in the antennal lobe and in the mushroom bodies. However, how the lateral horn participates in olfactory coding remains comparatively more enigmatic. We studied odor representation at the input to the lateral horn of the honeybee, a social insect that relies on both floral odors for foraging and pheromones for social communication. Using in vivo calcium imaging, we show consistent neural activity in the honeybee lateral horn upon stimulation with both floral volatiles and social pheromones. Recordings reveal odor-specific maps in this brain region as stimulations with the same odorant elicit more similar spatial activity patterns than stimulations with different odorants. Odor-similarity relationships are mostly conserved between antennal lobe and lateral horn, so that odor maps recorded in the lateral horn allow predicting bees' behavioral responses to floral odorants. In addition, a clear segregation of odorants based on pheromone type is found in both structures. The lateral horn thus contains an odor-specific map with distinct representations for the different bee pheromones, a prerequisite for eliciting specific behaviors.

  2. Chemical olfactory signals and parenthood in mammals.

    PubMed

    Corona, Rebeca; Lévy, Frédéric

    2015-02-01

    This article is part of a Special Issue "Chemosignals and Reproduction". In mammalian species, odor cues emitted by the newborn are essential to establish maternal behavior at parturition and coordinate early mother-infant interactions. Offspring odors become potent attractive stimuli at parturition promoting the contact with the young to ensure that normal maternal care develops. In some species odors provide a basis for individual recognition of the offspring and highly specialized neural mechanisms for learning the infant signals have evolved. Both the main and the accessory olfactory systems are involved in the onset of maternal care, but only the former contributes to individual odor discrimination of the young. Electrophysiological and neurochemical changes occur in the main olfactory bulb leading to a coding of the olfactory signature of the familiar young. Olfactory neurogenesis could also contribute to motherhood and associated learning. Parturition and interactions with the young influence neurogenesis and some evidence indicates a functional link between olfactory neurogenesis and maternal behavior. Although a simple compound has been found which regulates anogenital licking in the rat, studies identifying the chemical nature of these odors are lacking. Neonatal body odors seem to be particularly salient to human mothers who are able to identify their infant's odors. Recent studies have revealed some neural processing of these cues confirming the importance of mother-young chemical communication in our own species.

  3. Does stimulus appearance affect learning?

    PubMed

    Pothos, Emmanuel M; Chater, Nick; Ziori, Eleni

    2006-01-01

    We examined the learning process with 3 sets of stimuli that have identical symbolic structure but differ in appearance (meaningless letter strings, arrangements of geometric shapes, and sequences of cities). One hypothesis is that the learning process aims to encode symbolic regularity in the same way, largely regardless of appearance. Another is that different types of stimuli bias the learning process to operate in different ways. Using the experimental paradigm of artificial grammar learning, we provided a preliminary test of these hypotheses. In Experiments 1 and 2 we measured performance in terms of grammaticality and found no difference across the 3 sets of stimuli. In Experiment 3 we analyzed performance in terms of both grammaticality and chunk strength. Again we found no differences in performance. Our tentative conclusion is that the learning process aims to encode symbolic regularity independent of stimulus appearance.

  4. Poverty of the stimulus revisited.

    PubMed

    Berwick, Robert C; Pietroski, Paul; Yankama, Beracah; Chomsky, Noam

    2011-01-01

    A central goal of modern generative grammar has been to discover invariant properties of human languages that reflect "the innate schematism of mind that is applied to the data of experience" and that "might reasonably be attributed to the organism itself as its contribution to the task of the acquisition of knowledge" (Chomsky, 1971). Candidates for such invariances include the structure dependence of grammatical rules, and in particular, certain constraints on question formation. Various "poverty of stimulus" (POS) arguments suggest that these invariances reflect an innate human endowment, as opposed to common experience: Such experience warrants selection of the grammars acquired only if humans assume, a priori, that selectable grammars respect substantive constraints. Recently, several researchers have tried to rebut these POS arguments. In response, we illustrate why POS arguments remain an important source of support for appeal to a priori structure-dependent constraints on the grammars that humans naturally acquire.

  5. Anatomical and molecular consequences of Unilateral Naris Closure on two populations of olfactory sensory neurons expressing defined odorant receptors.

    PubMed

    Molinas, Adrien; Aoudé, Imad; Soubeyre, Vanessa; Tazir, Bassim; Cadiou, Hervé; Grosmaitre, Xavier

    2016-07-28

    Mammalian olfactory sensory neurons (OSNs), the primary elements of the olfactory system, are located in the olfactory epithelium lining the nasal cavity. Exposed to the environment, their lifespan is short. Consequently, OSNs are regularly regenerated and several reports show that activity strongly modulates their development and regeneration: the peripheral olfactory system can adjust to the amount of stimulus through compensatory mechanisms. Unilateral naris occlusion (UNO) was frequently used to investigate this mechanism at the entire epithelium level. However, there is little data regarding the effects of UNO at the cellular level, especially on individual neuronal populations expressing a defined odorant receptor. Here, using UNO during the first three postnatal weeks, we analyzed the anatomical and molecular consequences of sensory deprivation in OSNs populations expressing the MOR23 and M71 receptors. The density of MOR23-expressing neurons is decreased in the closed side while UNO does not affect the density of M71-expressing neurons. Using Real Time qPCR on isolated neurons, we observed that UNO modulates the transcript levels for transduction pathway proteins (odorant receptors, CNGA2, PDE1c). The transcripts modulated by UNO will differ between populations depending on the receptor expressed. These results suggest that sensory deprivation will have different effects on different OSNs' populations. As a consequence, early experience will shape the functional properties of OSNs differently depending on the type of odorant receptor they express.

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

    PubMed

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

    2013-01-01

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

  7. Application of artificial neural networks on mosquito Olfactory Receptor Neurons for an olfactory biosensor.

    PubMed

    Bachtiar, Luqman R; Unsworth, Charles P; Newcomb, Richard D

    2013-01-01

    Various odorants such as carbon dioxide (CO2) and 1-octen-3-ol, underlie the host-seeking behaviors of the major malaria vector Anopheles Gambiae. Highlighted by the olfactory processing strength of the mosquito, such a powerful olfactory sense could serve as the sensors of an artificial olfactory biosensor. In this work, we use the firing rates of the A. Gambiae mosquito Olfactory Receptor Neurons (ORNs), to train an Artificial Neural Network (ANN) for the classification of volatile odorants into their known chemical classes and assess their suitability for an olfactory biosensor. With the implementation of bootstrapping, a more representative result was obtained wherein we demonstrate the training of a hybrid ANN consisting of an array of Multi-Layer Perceptrons (MLPs) with optimal number of hidden neurons. The ANN system was able to correctly class 90.1% of the previously unseen odorants, thus demonstrating very strong evidence for the use of A. Gambiae olfactory receptors coupled with an ANN as an olfactory biosensor.

  8. Olfactory conditioning of the sting extension reflex in honeybees: Memory dependence on trial number, interstimulus interval, intertrial interval, and protein synthesis.

    PubMed

    Giurfa, Martin; Fabre, Eve; Flaven-Pouchon, Justin; Groll, Helga; Oberwallner, Barbara; Vergoz, Vanina; Roussel, Edith; Sandoz, Jean Christophe

    2009-12-01

    Harnessed bees learn to associate an odorant with an electric shock so that afterward the odorant alone elicits the sting extension response (SER). We studied the dependency of retention on interstimulus interval (ISI), intertrial interval (ITI), and number of conditioning trials in the framework of olfactory SER conditioning. Forward ISIs (conditioned stimulus [CS] before unconditioned stimulus [US]) supported higher retention than a backward one (US before CS) with an optimum around 3 sec. Spaced trials (ITI 10 min) supported higher retention than massed trials (ITI 1 min) and led to the formation of a late long-term memory (l-LTM) that depended on protein synthesis. Our results reaffirm olfactory SER conditioning as a reliable tool for the study of learning and memory.

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

    ERIC Educational Resources Information Center

    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…

  10. Individual olfactory perception reveals meaningful nonolfactory genetic information.

    PubMed

    Secundo, Lavi; Snitz, Kobi; Weissler, Kineret; Pinchover, Liron; Shoenfeld, Yehuda; Loewenthal, Ron; Agmon-Levin, Nancy; Frumin, Idan; Bar-Zvi, Dana; Shushan, Sagit; Sobel, Noam

    2015-07-14

    Each person expresses a potentially unique subset of ∼ 400 different olfactory receptor subtypes. Given that the receptors we express partially determine the odors we smell, it follows that each person may have a unique nose; to capture this, we devised a sensitive test of olfactory perception we termed the "olfactory fingerprint." Olfactory fingerprints relied on matrices of perceived odorant similarity derived from descriptors applied to the odorants. We initially fingerprinted 89 individuals using 28 odors and 54 descriptors. We found that each person had a unique olfactory fingerprint (P < 10(-10)), which was odor specific but descriptor independent. We could identify individuals from this pool using randomly selected sets of 7 odors and 11 descriptors alone. Extrapolating from this data, we determined that using 34 odors and 35 descriptors we could individually identify each of the 7 billion people on earth. Olfactory perception, however, fluctuates over time, calling into question our proposed perceptual readout of presumably stable genetic makeup. To test whether fingerprints remain informative despite this temporal fluctuation, building on the linkage between olfactory receptors and HLA, we hypothesized that olfactory perception may relate to HLA. We obtained olfactory fingerprints and HLA typing for 130 individuals, and found that olfactory fingerprint matching using only four odorants was significantly related to HLA matching (P < 10(-4)), such that olfactory fingerprints can save 32% of HLA tests in a population screen (P < 10(-6)). In conclusion, a precise measure of olfactory perception reveals meaningful nonolfactory genetic information.

  11. Modulation by cyclic GMP of the odour sensitivity of vertebrate olfactory receptor cells

    NASA Technical Reports Server (NTRS)

    Leinders-Zufall, T.; Shepherd, G. M.; Zufall, F.

    1996-01-01

    Recent evidence has indicated a significant role for the cGMP second messenger system in vertebrate olfactory transduction but no clear functions have been identified for cGMP so far. Here, we have examined the effects of 8-Br-cGMP and carbon monoxide (CO) on odour responses of salamander olfactory receptor neurons using perforated patch recordings. We report that 8-Br-cGMP strongly down-regulates the odour sensitivity of the cells, with a K1/2 of 460 nM. This adaptation-like effect can be mimicked by CO, an activator of soluble guanylyl cyclase, with a K1/2 of 1 microM. Sensitivity modulation is achieved through a regulatory chain of events in which cGMP stimulates a persistent background current due to the activation of cyclic nucleotide-gated channels. This in turn leads to sustained Ca2+ entry providing a negative feedback signal. One consequence of the Ca2+ entry is a shift to the right of the stimulus-response curve and a reduction in saturating odour currents. Together, these two effects can reduce the sensory generator current by up to twenty-fold. Thus, cGMP functions to control the gain of the G-protein coupled cAMP pathway. Another consequence of the action of cGMP is a marked prolongation of the odour response kinetics. The effects of CO/cGMP are long-lasting and can continue for minutes. Hence, we propose that cGMP helps to prevent saturation of the cell's response by adjusting the operational range of the cAMP cascade and contributes to olfactory adaptation by decreasing the sensitivity of olfactory receptor cells to repeated odour stimuli.

  12. Reading cinnamon activates olfactory brain regions.

    PubMed

    González, Julio; Barros-Loscertales, Alfonso; Pulvermüller, Friedemann; Meseguer, Vanessa; Sanjuán, Ana; Belloch, Vicente; Avila, César

    2006-08-15

    Some words immediately and automatically remind us of odours, smells and scents, whereas other language items do not evoke such associations. This study investigated, for the first time, the abstract linking of linguistic and odour information using modern neuroimaging techniques (functional MRI). Subjects passively read odour-related words ('garlic', 'cinnamon', 'jasmine') and neutral language items. The odour-related terms elicited activation in the primary olfactory cortex, which include the piriform cortex and the amygdala. Our results suggest the activation of widely distributed cortical cell assemblies in the processing of olfactory words. These distributed neuron populations extend into language areas but also reach some parts of the olfactory system. These distributed neural systems may be the basis of the processing of language elements, their related conceptual and semantic information and the associated sensory information.

  13. Laminar disorganisation of mitral cells in the olfactory bulb does not affect topographic targeting of primary olfactory axons.

    PubMed

    Royal, S J; Gambello, M J; Wynshaw-Boris, A; Key, B; Clarris, H J

    2002-04-05

    Primary olfactory neurons expressing the same odorant receptor protein typically project to topographically fixed olfactory bulb sites. While cell adhesion molecules and odorant receptors have been implicated in guidance of primary olfactory axons, the postsynaptic mitral cells may also have a role in final target selection. We have examined the effect of disorganisation of the mitral cell soma layer in mutant mice heterozygous for the beta-subunit of platelet activating factor acetylhydrolase (Lis1(-/+)) on the targeting of primary olfactory axons. Lis1(-/+) mice display abnormal lamination of neurons in the olfactory bulb. Lis1(-/+) mice were crossed with the P2-IRES-tau:LacZ line of transgenic mice that selectively expresses beta-galactosidase in primary olfactory neurons expressing the P2 odorant receptor. LacZ histochemistry revealed blue-stained P2 axons that targeted topographically fixed glomeruli in these mice in a manner similar to that observed in the parent P2-IRES-tau:LacZ line. Thus, despite the aberrant organisation of postsynaptic mitral cells in Lis1(-/+) mice, primary olfactory axons continued to converge and form glomeruli at correct sites in the olfactory bulb. Next we examined whether challenging primary olfactory axons in adult Lis(-/+) mice with regeneration would affect their ability to converge and form glomeruli. Following partial chemical ablation of the olfactory neuroepithelium with dichlobenil, primary olfactory neurons die and are replaced by newly differentiating neurons that project axons to the olfactory bulb where they converge and form glomeruli. Despite the aberrant mitral cell layer in Lis(-/+) mice, primary olfactory axons continued to converge and form glomeruli during regeneration. Together these results demonstrate that the convergence of primary olfactory axons during development and regeneration is not affected by gross perturbations to the lamination of the mitral cell layer. Thus, these results support evidence from

  14. Rapid odor perception in rat olfactory bulb by microelectrode array*

    PubMed Central

    Zhou, Jun; Dong, Qi; Zhuang, Liu-jing; Li, Rong; Wang, Ping

    2012-01-01

    Responses of 302 mitral/tufted (M/T) cells in the olfactory bulb were recorded from 42 anesthetized freely breathing rats using a 16-channel microwire electrode array. Saturated vapors of four pure chemicals, anisole, carvone, citral and isoamyl acetate were applied. After aligning spike trains to the initial phase of the inhalation after odor onset, the responses of M/T cells showed transient temporal features including excitatory and inhibitory patterns. Both odor-evoked patterns indicated that mammals recognize odors within a short respiration cycle after odor stimulus. Due to the small amount of information received from a single cell, we pooled results from all responsive M/T cells to study the ensemble activity. The firing rates of the cell ensembles were computed over 100 ms bins and population vectors were constructed. The high dimension vectors were condensed into three dimensions for visualization using principal component analysis. The trajectories of both excitatory and inhibitory cell ensembles displayed strong dynamics during odor stimulation. The distances among cluster centers were enlarged compared to those of the resting state. Thus, we presumed that pictures of odor information sent to higher brain regions were depicted and odor discrimination was completed within the first breathing cycle. PMID:23225857

  15. High olfactory sensitivity for dimethyl sulphide in harbour seals

    PubMed Central

    Kowalewsky, Sylvia; Dambach, Martin; Mauck, Björn; Dehnhardt, Guido

    2005-01-01

    Productive areas are patchily distributed at sea and represent important feeding grounds for many marine organisms. Although pinnipeds are known to travel on direct routes and return regularly to particular feeding sites, the environmental information seals use to perform this navigation is as yet unknown. As atmospheric dimethyl sulphide (DMS) has been demonstrated to be a reliable indicator for profitable foraging areas, we tested seals for their ability to smell DMS at concentrations typical for the marine environment. Using a go/no-go response paradigm we determined the DMS detection threshold in two harbour seals (Phoca vitulina vitulina). DMS stimuli from 8.05×108 to 8 pmol (DMS) m−3(air) were tested against a control stimulus using a custom-made olfactometer. DMS-thresholds determined for both seals (20 and 13 pmol m−3) indicate that seals can detect ambient concentrations associated with high primary productivity, e.g. in the North Atlantic. Thus, seals possess an extraordinarily high olfactory sensitivity for DMS, which could provide a sensory basis for identifying or orienting to profitable foraging grounds. PMID:17148339

  16. Olfactory regulation of mosquito–host interactions

    PubMed Central

    Zwiebel, L.J.; Takken, W.

    2011-01-01

    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 behaviors in so far as it significantly contributes to the ability of these mosquitoes to transmit pathogens that cause diseases such as dengue, yellow fever and most significantly human malaria. Here, we review significant advances in behavioral, physiological and molecular investigations into mosquito host preference, with a particular emphasis on studies that have emerged in the post-genomic era that seek to combine these approaches. PMID:15242705

  17. [Conjugated variability of spontaneous activity and behavioral response to olfactory stimuli in the taiga tick (Ixodes persulcatus)].

    PubMed

    Romashchenko, A V; Shnaĭder, E P; Petrovskiĭ, D V; Moshkin, M P

    2013-01-01

    According to -the automatic tracing of the movement of ticks in a Petri dish, motivational variability of the spontaneous activity and behavioral response of the taiga tick to olfactory stimuli was analyzed. In the studied sample, two groups of ticks that differ in the movement trajectory in the absence of stimulus were isolated, including ticks that mainly moved on the edge of the dish at maximum accessible height (group 1) and ticks that mainly moved at the bottom and wall of the dish (group 2). It was registered that ticks of group 1 (as opposed to ticks of group 2) demonstrated a pronounced behavioral response to olfactory stimuli (human synthetic pheromones and ammonia) and negative geotaxis. It was established that belonging to these groups depended On the time of day when the testing was performed and did not depend on the physiological age and infectious status.

  18. Olfactory sensations produced by high-energy photon irradiation of the olfactory receptor mucosa in humans

    SciTech Connect

    Sagar, S.M.; Thomas, R.J.; Loverock, L.T.; Spittle, M.F. )

    1991-04-01

    During irradiation of volumes that incorporate the olfactory system, a proportion of patients have complained of a pungent smell. A retrospective study was carried out to determine the prevalence of this side-effect. A questionnaire was sent to 40 patients whose treatment volumes included the olfactory region and also to a control group treated away from this region. The irradiated tumor volumes included the frontal lobe, whole brain, nasopharynx, pituitary fossa, and maxillary antrum. Of the 25 patients who replied, 60% experienced odorous symptoms during irradiation. They described the odor as unpleasant and consistent with ozone. Stimulation of olfactory receptors is considered to be caused by the radiochemical formation of ozone and free radicals in the mucus overlying the olfactory mucosa.

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

    PubMed Central

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

    2013-01-01

    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 mice were frankly anosmic when tested with pheromonal and non-pheromonal odors and failed to engage in aggressive behavior. Treated juvenile females failed to show puberty acceleration subsequent to exposure to bedding from adult males. Activation of the immediate early gene c-Fos and electro-vomeronasogram recording confirmed the integrity of the vomeronasal system in zinc sulfate treated mice. These results support the hypothesis that odor detection by the main olfactory epithelium is required to initiate sampling by the vomeronasal system. PMID:20377623

  20. Accessory olfactory bulb function is modulated by input from the main olfactory epithelium.

    PubMed

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

    2010-03-01

    Although 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 vomeronasal organ. 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 mice were frankly anosmic when tested with pheromonal and non-pheromonal odors and failed to engage in aggressive behavior. Treated juvenile females failed to show puberty acceleration subsequent to exposure to bedding from adult males. Activation of the immediate early gene c-Fos and electrovomeronasogram recording confirmed the integrity of the vomeronasal system in zinc sulfate-treated mice. These results support the hypothesis that odor detection by the main olfactory epithelium is required to initiate sampling by the vomeronasal system.

  1. Investigation of Stimulus-Response Compatibility Using a Startling Acoustic Stimulus

    ERIC Educational Resources Information Center

    Maslovat, Dana; Carlsen, Anthony N.; Franks, Ian M.

    2012-01-01

    We investigated the processes underlying stimulus-response compatibility by using a lateralized auditory stimulus in a simple and choice reaction time (RT) paradigm. Participants were asked to make either a left or right key lift in response to either a control (80dB) or startling (124dB) stimulus presented to either the left ear, right ear, or…

  2. Why Additional Presentations Help Identify a Stimulus

    ERIC Educational Resources Information Center

    Guest, Duncan; Kent, Christopher; Adelman, James S.

    2010-01-01

    Nosofsky (1983) reported that additional stimulus presentations within a trial increase discriminability in absolute identification, suggesting that each presentation creates an independent stimulus representation, but it remains unclear whether exposure duration or the formation of independent representations improves discrimination in such…

  3. Stimulus Intensity and the Perception of Duration

    ERIC Educational Resources Information Center

    Matthews, William J.; Stewart, Neil; Wearden, John H.

    2011-01-01

    This article explores the widely reported finding that the subjective duration of a stimulus is positively related to its magnitude. In Experiments 1 and 2 we show that, for both auditory and visual stimuli, the effect of stimulus magnitude on the perception of duration depends upon the background: Against a high intensity background, weak stimuli…

  4. Stimulus Probability Effects in Absolute Identification

    ERIC Educational Resources Information Center

    Kent, Christopher; Lamberts, Koen

    2016-01-01

    This study investigated the effect of stimulus presentation probability on accuracy and response times in an absolute identification task. Three schedules of presentation were used to investigate the interaction between presentation probability and stimulus position within the set. Data from individual participants indicated strong effects of…

  5. Stimulus Overselectivity: Empirical Basis and Diagnostic Methods

    ERIC Educational Resources Information Center

    Cipani, Ennio

    2012-01-01

    This paper presents the empirical basis for the phenomena known as stimulus overselectivity. Stimulus overselectivity involves responding on the basis of a restricted range of elements or features that are discriminative for reinforcement. The manner in which such a response pattern impedes the skill acquisition in children is identified. A…

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

    PubMed

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

    2014-12-01

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

  7. Shh-Proteoglycan Interactions Regulate Maturation of Olfactory Glomerular Circuitry

    PubMed Central

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

    2014-01-01

    The olfactory system relies on precise circuitry connecting olfactory sensory neurons (OSNs) and appropriate relay and processing neurons of the olfactory bulb (OB). In mammals, the exact correspondence between specific olfactory receptor types and individual glomeruli enables a spatially precise map of glomerular activation that corresponds to distinct odors. However, the mechanisms that govern the establishment and maintenance of the glomerular circuitry are largely unknown. Here we show that high levels of Sonic Hedgehog (Shh) signaling at multiple sites enable refinement and maintenance of olfactory glomerular circuitry. Mice expressing a mutant version of Shh (ShhAla/Ala), with impaired binding to proteoglycan co-receptors, exhibit disproportionately small olfactory bulbs containing fewer glomeruli. Notably, in mutant animals the correspondence between individual glomeruli and specific olfactory receptors is lost, as olfactory sensory neurons expressing different olfactory receptors converge on the same glomeruli. These deficits arise at late stages in post-natal development and continue into adulthood, indicating impaired pruning of erroneous connections within the olfactory bulb. In addition, mature ShhAla/Ala mice exhibit decreased proliferation in the subventricular zone (SVZ), with particular reduction in neurogenesis of calbindin-expressing periglomerular cells. Thus, Shh interactions with proteoglycan co-receptors function at multiple locations to regulate neurogenesis and precise olfactory connectivity, thereby promoting functional neuronal circuitry. PMID:24913191

  8. On the organization of olfactory and vomeronasal cortices.

    PubMed

    Martinez-Marcos, Alino

    2009-01-12

    Classically, the olfactory and vomeronasal pathways are thought to run in parallel non-overlapping axes in the forebrain subserving different functions. The olfactory and vomeronasal epithelia project to the main and accessory olfactory bulbs (primary projections), which in turn project to different areas of the telencephalon in a non-topographic fashion (secondary projections) and so on (tertiary projections). New data indicate that projections arising from the main and accessory olfactory bulbs converge widely in the rostral basal telencephalon. In contrast, in the vomeronasal system, cloning two classes of vomeronasal receptors (V1R and V2R) has led to the distinction of two anatomically and functionally independent pathways that reach some common, but also some different, targets in the amygdala. Tertiary projections from the olfactory and vomeronasal amygdalae are directed to the ventral striatum, which thus becomes a site for processing and potential convergence of chemosensory stimuli. Functional data indicate that the olfactory and vomeronasal systems are able to detect and process volatiles (presumptive olfactory cues) as well as pheromones in both epithelia and bulbs. Collectively, these data indicate that the anatomical and functional distinction between the olfactory and vomeronasal systems should be re-evaluated. Specifically, the recipient cortex should be reorganized to include olfactory, vomeronasal (convergent and V1R and V2R specific areas) and mixed (olfactory and vomeronasal) chemosensory cortices. This new perspective could help to unravel olfactory and vomeronasal interactions in behavioral paradigms.

  9. Olfactory perception, communication, and the nose-to-brain pathway.

    PubMed

    Stockhorst, Ursula; Pietrowsky, Reinhard

    2004-10-30

    The present paper's aim is of to give an overview about the basic knowledge as well as actual topics of olfaction--with a special regard on behavior. We summarize different functions of the nose and the olfactory system in human physiology and psychology. We will first describe the functional anatomy of the olfactory system in man. Afterwards, the function of the olfactory system will be viewed from an evolutionary and phylogenetic perspective. We will further outline the main features of olfactory perception, and will show how olfactory perception is influenced by learning. Olfactory signals are relevant stimuli that affect communication. Consequently, the role of the olfactory system in social interaction and mood will be described and gender differences will be addressed. Finally, the function of the nose as an interface to the brain, including implications for pharmacology, will be discussed.

  10. Sphenoid esthesioneuroblastoma arising from the hindmost olfactory filament.

    PubMed

    Matsunaga, Mami; Nakagawa, Takayuki; Sakamoto, Tatsunori; Ito, Juichi

    2015-04-01

    Esthesioneuroblastoma (ENB), or olfactory neuroblastoma, is a rare malignant neoplasm arising from the olfactory neuroepithelium. Typically, ENBs are found in the olfactory cleft with extension to the ethmoid sinuses or anterior skull base. Here we report a case of ENB located in the sphenoid sinus, which had been considered as an ectopic ENB. However, endoscopic resection revealed the continuity of the tumor with the hindmost olfactory filament. The present case suggests that an ENB in the sphenoid sinus was not ectopic, but arose from the normal olfactory neuroepithelium. This continuity of the ENB with this filament indicated that the tumor was not ectopic, and that there was possible tumor invasion into the olfactory neuroepithelium in the cribriform niche. Therefore, pathological examination of the olfactory neuroepithelium in the cribriform niche may be necessary in case of sphenoid ENBs.

  11. Functional Neuroanatomy of "Drosophila" Olfactory Memory Formation

    ERIC Educational Resources Information Center

    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…

  12. Adult Neurogenesis and the Olfactory System

    PubMed Central

    Whitman, Mary C.; Greer, Charles A.

    2009-01-01

    Though initially described in the early 1960s, it is only within the past decade that the concept of continuing adult neurogenesis has gained widespread acceptance. Neuroblasts from the subventricular zone (SVZ) migrate along the rostral migratory stream (RMS) into the olfactory bulb, where they differentiate into interneurons. Neuroblasts from the subgranular zone (SGZ) of the hippocampal formation show relatively little migratory behavior, and differentiate into dentate gyrus granule cells. In sharp contrast to embryonic and perinatal development, these newly differentiated neurons must integrate into a fully functional circuit, without disrupting ongoing performance. Here, after a brief historical overview and introduction to olfactory circuitry, we review recent advances in the biology of neural stem cells, mechanisms of migration in the RMS and olfactory bulb, differentiation and survival of new neurons, and finally mechanisms of synaptic integration. Our primary focus is on the olfactory system, but we also contrast the events occurring there with those in the hippocampal formation. Although both SVZ and SGZ neurogenesis are involved in some types of learning, their full functional significance remains unclear. Since both systems offer models of integration of new neuroblasts, there is immense interest in using neural stem cells to replace neurons lost in injury or disease. Though many questions remain unanswered, new insights appear daily about adult neurogenesis, regulatory mechanisms, and the fates of the progeny. We discuss here some of the central features of these advances, as well as speculate on future research directions. PMID:19615423

  13. Propagation of olfactory information in Drosophila.

    PubMed

    Root, Cory M; Semmelhack, Julia L; Wong, Allan M; Flores, Jorge; Wang, Jing W

    2007-07-10

    Investigating how information propagates between layers in the olfactory system is an important step toward understanding the olfactory code. Each glomerular output projection neuron (PN) receives two sources of input: the olfactory receptor neurons (ORNs) of the same glomerulus and interneurons that innervate many glomeruli. We therefore asked how these inputs interact to produce PN output. We used receptor gene mutations to silence all of the ORNs innervating a specific glomerulus and recorded PN activity with two-photon calcium imaging and electrophysiology. We found evidence for balanced excitatory and inhibitory synaptic inputs but saw little or no response in the absence of direct ORN input. We next asked whether any transformation of activity occurs at successive layers of the antennal lobe. We found a strong link between PN firing and dendritic calcium elevation, the latter of which is tightly correlated with calcium activity in ORN axons, supporting the idea of glomerular propagation of olfactory information. Finally, we showed that odors are represented by a sparse population of PNs. Together, these results are consistent with the idea that direct receptor input provides the main excitatory drive to PNs, whereas interneurons modulate PN output. Balanced excitatory and inhibitory interneuron input may provide a mechanism to adjust PN sensitivity.

  14. Olfactory Environment Design for Human Spaceflight

    NASA Astrophysics Data System (ADS)

    Welch, C. S.; Holland, F. J.

    2002-01-01

    Smell is usually deemed the least important of the five senses. To contradict this assertion, however, there is no shortage of scientific literature which concludes that olfaction is of very great significance to humans. Odours have been shown to have a variety of effects on humans, and are capable of changing both behaviour and cognitive processing in ways that we are frequently completely unconscious of. Examples of this include alertness, alteration of mood, capacity for ideation and intellectual performance. To date, the design of human spacecraft has concentrated on making their olfactory environments, where possible, `odour neutral' - that is ensuring that all unpleasant and/or offensive odours are removed. Here it suggested that spacecraft (and other extraterrestrial facilities for human inhabitation) might benefit from having their olfactory environments designed to be `odour positive', that is to use odours and olfaction for the positive benefit of their residents. This paper presents a summary of current olfactory research and considers both its positive and negative implications for humans in space. It then discusses `odour positive' design of spacecraft olfactory environments and the possible benefits accruing from this approach before examining its implications for the architecture of spacecraft environmental control systems.

  15. Acid sensing by the Drosophila olfactory system.

    PubMed

    Ai, Minrong; Min, Soohong; Grosjean, Yael; Leblanc, Charlotte; Bell, Rati; Benton, Richard; Suh, Greg S B

    2010-12-02

    The odour of acids has a distinct quality that is perceived as sharp, pungent and often irritating. How acidity is sensed and translated into an appropriate behavioural response is poorly understood. Here we describe a functionally segregated population of olfactory sensory neurons in the fruitfly, Drosophila melanogaster, that are highly selective for acidity. These olfactory sensory neurons express IR64a, a member of the recently identified ionotropic receptor (IR) family of putative olfactory receptors. In vivo calcium imaging showed that IR64a+ neurons projecting to the DC4 glomerulus in the antennal lobe are specifically activated by acids. Flies in which the function of IR64a+ neurons or the IR64a gene is disrupted had defects in acid-evoked physiological and behavioural responses, but their responses to non-acidic odorants remained unaffected. Furthermore, artificial stimulation of IR64a+ neurons elicited avoidance responses. Taken together, these results identify cellular and molecular substrates for acid detection in the Drosophila olfactory system and support a labelled-line mode of acidity coding at the periphery.

  16. Encoding olfactory signals via multiple chemosensory systems.

    PubMed

    Ma, Minghong

    2007-01-01

    Most animals have evolved multiple olfactory systems to detect general odors as well as social cues. The sophistication and interaction of these systems permit precise detection of food, danger, and mates, all crucial elements for survival. In most mammals, the nose contains two well described chemosensory apparatuses (the main olfactory epithelium and the vomeronasal organ), each of which comprises several subtypes of sensory neurons expressing distinct receptors and signal transduction machineries. In many species (e.g., rodents), the nasal cavity also includes two spatially segregated clusters of neurons forming the septal organ of Masera and the Grueneberg ganglion. Results of recent studies suggest that these chemosensory systems perceive diverse but overlapping olfactory cues and that some neurons may even detect the pressure changes carried by the airflow. This review provides an update on how chemosensory neurons transduce chemical (and possibly mechanical) stimuli into electrical signals, and what information each system brings into the brain. Future investigation will focus on the specific ligands that each system detects with a behavioral context and the processing networks that each system involves in the brain. Such studies will lead to a better understanding of how the multiple olfactory systems, acting in concert, offer a complete representation of the chemical world.

  17. Olfactory Learning in Individually Assayed Drosophila Larvae

    PubMed Central

    Scherer, Sabine; Stocker, Reinhard F.; Gerber, Bertram

    2003-01-01

    Insect and mammalian olfactory systems are strikingly similar. Therefore, Drosophila can be used as a simple model for olfaction and olfactory learning. The brain of adult Drosophila, however, is still complex. We therefore chose to work on the larva with its yet simpler but adult-like olfactory system and provide evidence for olfactory learning in individually assayed Drosophila larvae. We developed a differential conditioning paradigm in which odorants are paired with positive (“+” fructose) or negative (“-” quinine or sodium chloride) gustatory reinforcers. Test performance of individuals from two treatment conditions is compared—one received odorant A with the positive reinforcer and odorant B with a negative reinforcer (A+/B-); animals from the other treatment condition were trained reciprocally (A-/B+). During test, differences in choice between A and B of individuals having undergone either A+/B- or A-/B+ training therefore indicate associative learning. We provide such evidence for both combinations of reinforcers; this was replicable across repetitions, laboratories, and experimenters. We further show that breaks improve performance, in accord with basic principles of associative learning. The present individual assay will facilitate electrophysiological studies, which necessarily use individuals. As such approaches are established for the larval neuromuscular synapse, but not in adults, an individual larval learning paradigm will serve to link behavioral levels of analysis to synaptic physiology. PMID:12773586

  18. Innate olfactory preferences in dung beetles.

    PubMed

    Dormont, Laurent; Jay-Robert, Pierre; Bessière, Jean-Marie; Rapior, Sylvie; Lumaret, Jean-Pierre

    2010-09-15

    The effects of insect larval diet on adult olfactory responses to host-plant or food volatiles are still debated. The induction of adult host preferences has been studied in insects with diverse ecologies, including parasitoids, flower-visitors and phytophagous species. We investigated this question for the first time in a coprophagous insect species. Larvae of the French scarab dung beetle Agrilinus constans were reared on four different artificial substrates containing dung from cattle, horse, sheep or wild boar, and responses of imagos to dung volatiles were then behaviourally tested in an olfactometer. We also reported the first analysis of the composition of different mammal dung volatiles. We showed that adult beetles were more attracted to cattle and sheep dung odours, and that larval feeding experience had no effect on the adult olfactory responses to dung volatiles. A second experiment showed that the presence of other insects inside the dung resource affects the process of dung selection by adults. We identified 64 chemical compounds from dung emissions, and showed that dung volatiles clearly differed among different mammal species, allowing olfactory discrimination by dung beetles. Our results suggest that resource selection in coprophagous insects may be based on innate olfactory preferences. Further experiments should examine whether Agrilinus adults can learn new dung odours, and whether larval diet may influence the behaviour of adults in other coprophagous species.

  19. Sex differences in the human olfactory system.

    PubMed

    Garcia-Falgueras, Alicia; Junque, Carme; Giménez, Mónica; Caldú, Xavier; Segovia, Santiago; Guillamon, Antonio

    2006-10-20

    The olfactory system (accessory) implicated in reproductive physiology and behavior in mammals is sexually dimorphic. These brain sex differences present two main characteristics: they are seen in neural circuits related to sexual behavior and sexual physiology and they take one of two opposite morphological patterns (male>female or female>male). The present work reports sex differences in the olfactory system in a large homogeneous sample of men (40) and women (51) using of voxel-based morphology. Gray matter concentration showed sexual dimorphism in several olfactory regions. Women have a higher concentration in the orbitofrontal cortex involving Brodmann's areas 10, 11 and 25 and temporomedial cortex (bilateral hippocampus and right amygdala), as well as their left basal insular cortex. In contrast, men show a higher gray matter concentration in the left entorhinal cortex (Brodmann's area 28), right ventral pallidum, dorsal left insular cortex and a region of the orbitofrontal cortex (Brodmann's area 25). This study supports the hypothesis that the mammalian olfactory system is a sexually dimorphic network and provides a theoretical framework for the morphofunctional approach to sex differences in the human brain.

  20. Immunocytochemical characterisation of olfactory ensheathing cells of zebrafish

    PubMed Central

    Lazzari, Maurizio; Bettini, Simone; Franceschini, Valeria

    2014-01-01

    Continuous lifelong neurogenesis is typical of the vertebrate olfactory system. The regenerative ability of olfactory receptor neurons is dependent on the glial cell type specific to the olfactory pathway, designated ‘olfactory ensheathing cells'. Several studies to date have focused on mammalian olfactory ensheathing cells, owing to their potential roles in cell-based therapy for spinal cord injury repair. However, limited information is available regarding this glial cell type in non-mammalian vertebrates, particularly anamniotes. In the current immunocytochemical study, we analysed the features of olfactory ensheathing cells in the zebrafish, Danio rerio. Fish provide a good model for studying glial cells associated with the olfactory pathway of non-mammalian vertebrates. In particular, zebrafish has numerous valuable features that enable its use as a prime model organism for genetic, neurobiological and developmental studies, as well as toxicology and genomics research. Paraffin sections from decalcified heads of zebrafish were processed immunocytochemically to detect proteins used in the research on mammalian olfactory ensheathing cells, including glial fibrillary acid protein (GFAP), S100, neural cell adhesion molecule (NCAM), polysialylated NCAM (PSA-NCAM), vimentin (VIM), p75NTR and galactin (Gal)-1. Notably, GFAP, S100, NCAM and Gal-1 were clearly observed, whereas no vimentin staining was detected. Weak immunostaining for PSA-NCAM and p75NTR was evident. Moreover the degree of marker expression was not uniform in various tracts of the zebrafish olfactory pathway. The immunostaining patterns of the zebrafish olfactory system are distinct from those of other fish to some extent, suggesting interspecific differences. We also showed that the olfactory pathway of zebrafish expresses markers of mammalian olfactory ensheathing cells. The olfactory systems of vertebrates have similarities but there are also marked variations between them. The issue of whether

  1. Intensity invariant dynamics and odor-specific latencies in olfactory receptor neuron response.

    PubMed

    Martelli, Carlotta; Carlson, John R; Emonet, Thierry

    2013-04-10

    Odors elicit spatiotemporal patterns of activity in the brain. Spatial patterns arise from the specificity of the interaction between odorants and odorant receptors expressed in different olfactory receptor neurons (ORNs), but the origin of temporal patterns of activity and their role in odor coding remain unclear. We investigate how physiological aspects of ORN response and physical aspects of odor stimuli give rise to diverse responses in Drosophila ORNs. We show that odor stimuli have intrinsic dynamics that depend on odor type and strongly affect ORN response. Using linear-nonlinear modeling to remove the contribution of the stimulus dynamics from the ORN dynamics, we study the physiological properties of the response to different odorants and concentrations. For several odorants and receptor types, the ORN response dynamics normalized by the peak response are independent of stimulus intensity for a large portion of the dynamic range of the neuron. Adaptation to a background odor changes the gain and dynamic range of the response but does not affect normalized response dynamics. Stimulating ORNs with various odorants reveals significant odor-dependent delays in the ORN response functions. However, these differences can be dominated by differences in stimulus dynamics. In one case the response of one ORN to two odorants is predicted solely from measurements of the odor signals. Within a large portion of their dynamic range, ORNs can capture information about stimulus dynamics independently from intensity while introducing odor-dependent delays. How insects might use odor-specific stimulus dynamics and ORN dynamics in discrimination and navigation tasks remains an open question.

  2. Olfactory perception, cognition, and dysfunction in humans.

    PubMed

    Stevenson, Richard J

    2013-05-01

    The main functions of olfaction relate to finding food, avoiding predators and disease, and social communication. Its role in detecting food has resulted in a unique dual mode sensory system. Environmental odorants are 'smelled' via the external nostrils, while volatile chemicals in food-detected by the same receptors-arrive via the nasopharynx, contributing to flavor. This arrangement allows the brain to link the consequences of eating with a food's odor, and then later to use this information in the search for food. Recognizing an odorant-a food, mate, or predator-requires the detection of complex chemical blends against a noisy chemical background. The brain solves this problem in two ways. First, by rapid adaptation to background odorants so that new odorants stand out. Second, by pattern matching the neural representation of an odorant to prior olfactory experiences. This account is consistent with olfactory sensory physiology, anatomy, and psychology. Odor perception, and its products, may be subject to further processing-olfactory cognition. While olfactory cognition has features in common with visual or auditory cognition, several aspects are unique, and even those that are common may be instantiated in different ways. These differences can be productively used to evaluate the generality of models of cognition and consciousness. Finally, the olfactory system can breakdown, and this may be predictive of the onset of neurodegenerative conditions such as Alzheimer's, as well as having prognostic value in other disorders such as schizophrenia. WIREs Cogn Sci 2013, 4:273-284. doi: 10.1002/wcs.1224 For further resources related to this article, please visit the WIREs website.

  3. Electrophysiological evidence for acidic, basic, and neutral amino acid olfactory receptor sites in the catfish

    PubMed Central

    1984-01-01

    Electrophysiological experiments indicate that olfactory receptors of the channel catfish, Ictalurus punctatus, contain different receptor sites for the acidic (A), basic (B), and neutral amino acids; further, at least two partially interacting neutral sites exist, one for the hydrophilic neutral amino acids containing short side chains (SCN), and the second for the hydrophobic amino acids containing long side chains (LCN). The extent of cross-adaptation was determined by comparing the electro-olfactogram (EOG) responses to 20 "test" amino acids during continuous bathing of the olfactory mucosa with water only (control) to those during each of the eight "adapting" amino acid regimes. Both the adapting and test amino acids were adjusted in concentrations to provide approximately equal response magnitudes in the unadapted state. Under all eight adapting regimes, the test EOG responses were reduced from those obtained in the unadapted state, but substantial quantitative differences resulted, depending upon the molecular structure of the adapting stimulus. Analyses of the patterns of EOG responses to the test stimuli identified and characterized the respective "transduction processes," a term used to describe membrane events initiated by a particular subset of amino acid stimuli that are intricately linked to the origin of the olfactory receptor potential. Only when the stimulus compounds interact with different transduction processes are the stimuli assumed to bind to different membrane "sites." Four relatively independent L-alpha-amino acid transduction processes (and thus at least four binding sites) identified in this report include: (a) the A process for aspartic and glutamic acids; (b) the B process for arginine and lysine; (c) the SCN process for glycine, alanine, serine, glutamine, and possibly cysteine; (d) the LCN process for methionine, ethionine, valine, norvaline, leucine, norleucine, glutamic acid-gamma-methyl ester, histidine, phenylalanine, and also

  4. Gyrodactylus salmonis infection impairs the olfactory system of rainbow trout.

    PubMed

    Lari, E; Pyle, G G

    2017-01-20

    Monogenean worms are ectoparasites that are known to be infectious to a wide variety of fish. Few species of monogenean parasites have been reported in the olfactory chamber of fish in current peer-reviewed literature. However, the impacts of these parasites on the olfactory system are not well understood. In this study, the effects of Gyrodactylus salmonis on the olfactory system structure and performance were investigated in rainbow trout (Oncorhynchus mykiss). The olfactory performance of the infected fish was examined using an electro-olfactography (EOG) technique, while the ultrastructure of the olfactory rosette was studied using scanning electron microscopy (SEM) and light microscopy (LM). The infected rainbow trout displayed reduced responses to two standard olfactory cues (L-alanine and TCA). The SEM micrographs revealed that many regions of the olfactory epithelium in the infected fish were heavily pitted and the LM examination of the olfactory epithelium showed local proliferation of mucous cells in the sensory regions as compared to the control group. The results of this study demonstrated that G. salmonis causes physical damage to the olfactory system of fish that lead to olfactory impairment.

  5. Early olfactory experience induces structural changes in the primary olfactory center of an insect brain.

    PubMed

    Arenas, A; Giurfa, M; Sandoz, J C; Hourcade, B; Devaud, J M; Farina, W M

    2012-03-01

    The antennal lobe (AL) is the first olfactory center of the insect brain and is constituted of different functional units, the glomeruli. In the AL, odors are coded as spatiotemporal patterns of glomerular activity. In honeybees, olfactory learning during early adulthood modifies neural activity in the AL on a long-term scale and also enhances later memory retention. By means of behavioral experiments, we first verified that olfactory learning between the fifth and eighth day of adulthood induces better retention performances at a late adult stage than the same experience acquired before or after this period. We checked that the specificity of memory for the odorants used was improved. We then studied whether such early olfactory learning also induces long-term structural changes in the AL consistent with the formation of long-term olfactory memories. We also measured the volume of 15 identified glomeruli in the ALs of 17-day-old honeybees that either experienced an odor associated with sucrose solution between the fifth and eighth day of adulthood or were left untreated. We found that early olfactory experience induces glomerulus-selective increases in volume that were specific to the learned odor. By comparing our volumetric measures with calcium-imaging recordings from a previous study, performed in 17-day-old bees subjected to the same treatment and experimental conditions, we found that glomeruli that showed structural changes after early learning were those that exhibited a significant increase in neural activity. Our results make evident a correlation between structural and functional changes in the AL following early olfactory learning.

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

    PubMed

    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.

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

    PubMed

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

    2003-01-01

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

  8. Continuous- and discrete-time stimulus sequences for high stimulus rate paradigm in evoked potential studies.

    PubMed

    Wang, Tao; Huang, Jiang-hua; Lin, Lin; Zhan, Chang'an A

    2013-01-01

    To obtain reliable transient auditory evoked potentials (AEPs) from EEGs recorded using high stimulus rate (HSR) paradigm, it is critical to design the stimulus sequences of appropriate frequency properties. Traditionally, the individual stimulus events in a stimulus sequence occur only at discrete time points dependent on the sampling frequency of the recording system and the duration of stimulus sequence. This dependency likely causes the implementation of suboptimal stimulus sequences, sacrificing the reliability of resulting AEPs. In this paper, we explicate the use of continuous-time stimulus sequence for HSR paradigm, which is independent of the discrete electroencephalogram (EEG) recording system. We employ simulation studies to examine the applicability of the continuous-time stimulus sequences and the impacts of sampling frequency on AEPs in traditional studies using discrete-time design. Results from these studies show that the continuous-time sequences can offer better frequency properties and improve the reliability of recovered AEPs. Furthermore, we find that the errors in the recovered AEPs depend critically on the sampling frequencies of experimental systems, and their relationship can be fitted using a reciprocal function. As such, our study contributes to the literature by demonstrating the applicability and advantages of continuous-time stimulus sequences for HSR paradigm and by revealing the relationship between the reliability of AEPs and sampling frequencies of the experimental systems when discrete-time stimulus sequences are used in traditional manner for the HSR paradigm.

  9. Continuous- and Discrete-Time Stimulus Sequences for High Stimulus Rate Paradigm in Evoked Potential Studies

    PubMed Central

    Wang, Tao; Huang, Jiang-hua; Lin, Lin

    2013-01-01

    To obtain reliable transient auditory evoked potentials (AEPs) from EEGs recorded using high stimulus rate (HSR) paradigm, it is critical to design the stimulus sequences of appropriate frequency properties. Traditionally, the individual stimulus events in a stimulus sequence occur only at discrete time points dependent on the sampling frequency of the recording system and the duration of stimulus sequence. This dependency likely causes the implementation of suboptimal stimulus sequences, sacrificing the reliability of resulting AEPs. In this paper, we explicate the use of continuous-time stimulus sequence for HSR paradigm, which is independent of the discrete electroencephalogram (EEG) recording system. We employ simulation studies to examine the applicability of the continuous-time stimulus sequences and the impacts of sampling frequency on AEPs in traditional studies using discrete-time design. Results from these studies show that the continuous-time sequences can offer better frequency properties and improve the reliability of recovered AEPs. Furthermore, we find that the errors in the recovered AEPs depend critically on the sampling frequencies of experimental systems, and their relationship can be fitted using a reciprocal function. As such, our study contributes to the literature by demonstrating the applicability and advantages of continuous-time stimulus sequences for HSR paradigm and by revealing the relationship between the reliability of AEPs and sampling frequencies of the experimental systems when discrete-time stimulus sequences are used in traditional manner for the HSR paradigm. PMID:23606900

  10. Differential Muscarinic Modulation in the Olfactory Bulb

    PubMed Central

    Smith, Richard S.; Hu, Ruilong; DeSouza, Andre; Eberly, Christian L.; Krahe, Krista; Chan, Wilson

    2015-01-01

    Neuromodulation of olfactory circuits by acetylcholine (ACh) plays an important role in odor discrimination and learning. Early processing of chemosensory signals occurs in two functionally and anatomically distinct regions, the main and accessory olfactory bulbs (MOB and AOB), which receive extensive cholinergic input from the basal forebrain. Here, we explore the regulation of AOB and MOB circuits by ACh, and how cholinergic modulation influences olfactory-mediated behaviors in mice. Surprisingly, despite the presence of a conserved circuit, activation of muscarinic ACh receptors revealed marked differences in cholinergic modulation of output neurons: excitation in the AOB and inhibition in the MOB. Granule cells (GCs), the most abundant intrinsic neuron in the OB, also exhibited a complex muscarinic response. While GCs in the AOB were excited, MOB GCs exhibited a dual muscarinic action in the form of a hyperpolarization and an increase in excitability uncovered by cell depolarization. Furthermore, ACh influenced the input–output relationship of mitral cells in the AOB and MOB differently showing a net effect on gain in mitral cells of the MOB, but not in the AOB. Interestingly, despite the striking differences in neuromodulatory actions on output neurons, chemogenetic inhibition of cholinergic neurons produced similar perturbations in olfactory behaviors mediated by these two regions. Decreasing ACh in the OB disrupted the natural discrimination of molecularly related odors and the natural investigation of odors associated with social behaviors. Thus, the distinct neuromodulation by ACh in these circuits could underlie different solutions to the processing of general odors and semiochemicals, and the diverse olfactory behaviors they trigger. SIGNIFICANCE STATEMENT State-dependent cholinergic modulation of brain circuits is critical for several high-level cognitive functions, including attention and memory. Here, we provide new evidence that cholinergic

  11. Tunicamycin impairs olfactory learning and synaptic plasticity in the olfactory bulb.

    PubMed

    Tong, Jia; Okutani, Fumino; Murata, Yoshihiro; Taniguchi, Mutsuo; Namba, Toshiharu; Wang, Yu-Jie; Kaba, Hideto

    2017-03-06

    Tunicamycin (TM) induces endoplasmic reticulum (ER) stress and inhibits N-glycosylation in cells. ER stress is associated with neuronal death in neurodegenerative disorders, such as Parkinson's disease and Alzheimer's disease, and most patients complain of the impairment of olfactory recognition. Here we examined the effects of TM on aversive olfactory learning and the underlying synaptic plasticity in the main olfactory bulb (MOB). Behavioral experiments demonstrated that the intrabulbar infusion of TM disabled aversive olfactory learning without affecting short-term memory. Histological analyses revealed that TM infusion upregulated C/EBP homologous protein (CHOP), a marker of ER stress, in the mitral and granule cell layers of MOB. Electrophysiological data indicated that TM inhibited tetanus-induced long-term potentiation (LTP) at the dendrodendritic excitatory synapse from mitral to granule cells. A low dose of TM (250nM) abolished the late phase of LTP, and a high dose (1μM) inhibited the early and late phases of LTP. Further, high-dose, but not low-dose, TM reduced the paired-pulse facilitation ratio, suggesting that the inhibitory effects of TM on LTP are partially mediated through the presynaptic machinery. Thus, our results support the hypothesis that TM-induced ER stress impairs olfactory learning by inhibiting synaptic plasticity via presynaptic and postsynaptic mechanisms in MOB.

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

    PubMed

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

    2014-09-01

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

  13. Olfactory drug effects approached from human-derived data.

    PubMed

    Lötsch, Jörn; Knothe, Claudia; Lippmann, Catharina; Ultsch, Alfred; Hummel, Thomas; Walter, Carmen

    2015-11-01

    The complexity of the sense of smell makes adverse olfactory effects of drugs highly likely, which can impact a patient's quality of life. Here, we present a bioinformatics approach that identifies drugs with potential olfactory effects by connecting drug target expression patterns in human olfactory tissue with drug-related information and the underlying molecular drug targets taken from publically available databases. We identified 71 drugs with listed olfactory effects and 147 different targets. Taking the target-based approach further, we found additional drugs with potential olfactory effects, including 152 different substances interacting with genes expressed in the human olfactory bulb. Our proposed bioinformatics approach provides plausible hypotheses about mechanistic drug effects for drug discovery and repurposing and, thus, would be appropriate for use during drug development.

  14. Tactile localization depends on stimulus intensity.

    PubMed

    Steenbergen, Peter; Buitenweg, Jan R; Trojan, Jörg; Veltink, Peter H

    2014-02-01

    Few experimental data are available about the influence of stimulus intensity on localization of cutaneous stimuli. The localization behavior of an individual as function of the veridical stimulus sites can be represented in the form of a perceptual map. It is unknown how the intensity of cutaneous stimuli influences these perceptual maps. We investigated the effect of stimulus intensity on trial-to-trial localization variability and on perceptual maps. We applied non-painful electrocutaneous stimuli of three different intensities through seven surface electrodes on the lower arm of healthy participants. They localized the stimuli on a tablet monitor mounted directly above their arm, on which a photograph of this arm was presented. The length of the arm over which the stimuli were localized was contracted when compared to the real electrode positions. This length increased toward veridical with increasing stimulus intensity. The trial-to-trial variance of the localizations dropped significantly with increasing intensity. Furthermore, localization biases of individual stimulus positions were shown to decrease with increasing stimulus intensity. We conclude that tactile stimuli are localized closer to veridical with increasing intensity in two respects: the localizations become more consistent and more accurate.

  15. Observing Behavior and Atypically Restricted Stimulus Control

    PubMed Central

    Dube, William V; Dickson, Chata A; Balsamo, Lyn M; O'Donnell, Kristin Lombard; Tomanari, Gerson Y; Farren, Kevin M; Wheeler, Emily E; McIlvane, William J

    2010-01-01

    Restricted stimulus control refers to discrimination learning with atypical limitations in the range of controlling stimuli or stimulus features. In the study reported here, 4 normally capable individuals and 10 individuals with intellectual disabilities (ID) performed two-sample delayed matching to sample. Sample-stimulus observing was recorded with an eye-tracking apparatus. High accuracy scores indicated stimulus control by both sample stimuli for the 4 nondisabled participants and 4 participants with ID, and eye tracking data showed reliable observing of all stimuli. Intermediate accuracy scores indicated restricted stimulus control for the remaining 6 participants. Their eye-tracking data showed that errors were related to failures to observe sample stimuli and relatively brief observing durations. Five of these participants were then given interventions designed to improve observing behavior. For 4 participants, the interventions resulted initially in elimination of observing failures, increased observing durations, and increased accuracy. For 2 of these participants, contingencies sufficient to maintain adequate observing were not always sufficient to maintain high accuracy; subsequent procedure modifications restored it, however. For the 5th participant, initial improvements in observing were not accompanied by improved accuracy, an apparent instance of observing without attending; accuracy improved only after an additional intervention that imposed contingencies on observing behavior. Thus, interventions that control observing behavior seem necessary but may not always be sufficient for the remediation of restricted stimulus control. PMID:21541173

  16. A monocular contribution to stimulus rivalry.

    PubMed

    Brascamp, Jan; Sohn, Hansem; Lee, Sang-Hun; Blake, Randolph

    2013-05-21

    When corresponding areas of the two eyes view dissimilar images, stable perception gives way to visual competition wherein perceptual awareness alternates between those images. Moreover, a given image can remain visually dominant for several seconds at a time even when the competing images are swapped between the eyes multiple times each second. This perceptual stability across eye swaps has led to the widespread belief that this unique form of visual competition, dubbed stimulus rivalry, is governed by eye-independent neural processes at a purely binocular stage of cortical processing. We tested this idea by investigating the influence of stimulus rivalry on the buildup of the threshold elevation aftereffect, a form of contrast adaptation thought to transpire at early cortical stages that include eye-specific neural activity. Weaker threshold elevation aftereffects were observed when the adapting image was engaged in stimulus rivalry than when it was not, indicating diminished buildup of adaptation during stimulus-rivalry suppression. We then confirmed that this reduction occurred, in part, at eye-specific neural stages by showing that suppression of an image at a given moment specifically diminished adaptation associated with the eye viewing the image at that moment. Considered together, these results imply that eye-specific neural events at early cortical processing stages contribute to stimulus rivalry. We have developed a computational model of stimulus rivalry that successfully implements this idea.

  17. Single stimulus learning in zebrafish larvae

    PubMed Central

    O’Neale, Ashley; Ellis, Joseph; Creton, Robbert; Colwill, Ruth M.

    2014-01-01

    Learning about a moving visual stimulus was examined in zebrafish larvae using an automated imaging system and a t1-t2 design. In three experiments, zebrafish larvae were exposed to one of two inputs at t1 (either a gray bouncing disk or an identical but stationary disk) followed by a common test at t2 (the gray bouncing disk). Using 7 days post-fertilization (dpf) larvae and 12 stimulus exposures, Experiment 1 established that these different treatments produced differential responding to the moving disk during testing. Larvae familiar with the moving test stimulus were significantly less likely to be still in its presence than larvae that had been exposed to the identical but stationary stimulus. Experiment 2 confirmed this result in 7 dpf larvae and extended the finding to 5 and 6 dpf larvae. Experiment 3 found differential responding to the moving test stimulus with 4 or 8 stimulus exposures but not with just one exposure in 7 dpf larvae. These results provide evidence for learning in very young zebrafish larvae. The merits and challenges of the t1-t2 framework to study learning are discussed. PMID:24012906

  18. Occlusion for stimulus deprivation amblyopia

    PubMed Central

    Antonio-Santos, Aileen; Vedula, Satyanarayana S; Hatt, Sarah R; Powell, Christine

    2014-01-01

    Background Stimulus deprivation amblyopia (SDA) develops due to an obstruction to the passage of light secondary to a condition such as cataract. The obstruction prevents formation of a clear image on the retina. SDA can be resistant to treatment, leading to poor visual prognosis. SDA probably constitutes less than 3% of all amblyopia cases, although precise estimates of prevalence are unknown. In developed countries, most patients present under the age of one year; in less developed parts of the world patients are likely to be older at the time of presentation. The mainstay of treatment is removal of the cataract and then occlusion of the better-seeing eye, but regimens vary, can be difficult to execute, and traditionally are believed to lead to disappointing results. Objectives Our objective was to evaluate the effectiveness of occlusion therapy for SDA in an attempt to establish realistic treatment outcomes. Where data were available, we also planned to examine evidence of any dose response effect and to assess the effect of the duration, severity, and causative factor on the size and direction of the treatment effect. Search methods We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2013, Issue 9), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to October 2013), EMBASE (January 1980 to October 2013), the Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to October 2013), PubMed (January 1946 to October 2013), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 28 October 2013. Selection criteria We planned

  19. Divisive normalization in olfactory population codes

    PubMed Central

    Olsen, Shawn R; Bhandawat, Vikas; Wilson, Rachel Irene

    2010-01-01

    In many regions of the visual system, the activity of a neuron is normalized by the activity of other neurons in the same region. Here we show that a similar normalization occurs during olfactory processing in the Drosophila antennal lobe. We exploit the orderly anatomy of this circuit to independently manipulate feedforward and lateral input to second-order projection neurons (PNs). Lateral inhibition increases the level of feedforward input needed to drive PNs to saturation, and this normalization scales with the total activity of the olfactory receptor neuron (ORN) population. Increasing total ORN activity also makes PN responses more transient. Strikingly, a model with just two variables (feedforward and total ORN activity) accurately predicts PN odor responses. Finally, we show that discrimination by a linear decoder is facilitated by two complementary transformations: the saturating transformation intrinsic to each processing channel boosts weak signals, while normalization helps equalize responses to different stimuli. PMID:20435004

  20. Mirror Sniffing: Humans Mimic Olfactory Sampling Behavior

    PubMed Central

    2014-01-01

    Ample evidence suggests that social chemosignaling plays a significant role in human behavior. Processing of odors and chemosignals depends on sniffing. Given this, we hypothesized that humans may have evolved an automatic mechanism driving sniffs in response to conspecific sniffing. To test this, we measured sniffing behavior of human subjects watching the movie Perfume, which contains many olfactory sniffing events. Despite the total absence of odor, observers sniffed when characters in the movie sniffed. Moreover, this effect was most pronounced in scenes where subjects heard the sniff but did not see the sniffed-at object. We liken this response to the orienting towards conspecific gaze in vision and argue that its robustness further highlights the significance of olfactory information processing in human behavior. PMID:24457159

  1. Olfactory kin recognition in a songbird.

    PubMed

    Krause, E Tobias; Krüger, Oliver; Kohlmeier, Philip; Caspers, Barbara A

    2012-06-23

    The ability to recognize close relatives in order to cooperate or to avoid inbreeding is widespread across all taxa. One accepted mechanism for kin recognition in birds is associative learning of visual or acoustic cues. However, how could individuals ever learn to recognize unfamiliar kin? Here, we provide the first evidence for a novel mechanism of kin recognition in birds. Zebra finch (Taeniopygia guttata) fledglings are able to distinguish between kin and non-kin based on olfactory cues alone. Since olfactory cues are likely to be genetically based, this finding establishes a neglected mechanism of kin recognition in birds, particularly in songbirds, with potentially far-reaching consequences for both kin selection and inbreeding avoidance.

  2. Subthreshold olfactory stimulation can enhance sweetness.

    PubMed

    Labbe, D; Rytz, A; Morgenegg, C; Ali, S; Martin, N

    2007-03-01

    The impact of olfactory perception on sweetness was explored in a model solution using odorants at subthreshold concentrations. First, the impact of 6 odorants, previously described in the literature as congruent with sweetness, was investigated at suprathreshold level in a sucrose solution. Ethyl butyrate and maltol were selected as they had the highest and the lowest sweetness-enhancing properties, respectively. Second, the impact on sweetness of the 2 odorants was investigated at subthreshold concentrations. A system delivering a continuous liquid flow at the same sucrose level, but with varying odorant concentrations, was used. At a subthreshold level, ethyl butyrate but not maltol significantly enhanced the sweetness of the sucrose solution. This study highlights that olfactory perception induced by odorants at a subthreshold level can significantly modulate taste perception. Finally, contrary to results observed with ethyl butyrate at suprathreshold levels, at subthreshold levels, the intensity of sweetness enhancement was not proportional to ethyl butyrate concentration.

  3. Olfactory Orientation and Navigation in Humans

    PubMed Central

    Jacobs, Lucia F.; Arter, Jennifer; Cook, Amy; Sulloway, Frank J.

    2015-01-01

    Although predicted by theory, there is no direct evidence that an animal can define an arbitrary location in space as a coordinate location on an odor grid. Here we show that humans can do so. Using a spatial match-to-sample procedure, humans were led to a random location within a room diffused with two odors. After brief sampling and spatial disorientation, they had to return to this location. Over three conditions, participants had access to different sensory stimuli: olfactory only, visual only, and a final control condition with no olfactory, visual, or auditory stimuli. Humans located the target with higher accuracy in the olfaction-only condition than in the control condition and showed higher accuracy than chance. Thus a mechanism long proposed for the homing pigeon, the ability to define a location on a map constructed from chemical stimuli, may also be a navigational mechanism used by humans. PMID:26083337

  4. Endocannabinoid modulation in the olfactory epithelium.

    PubMed

    Breunig, Esther; Czesnik, Dirk; Piscitelli, Fabiana; Di Marzo, Vincenzo; Manzini, Ivan; Schild, Detlev

    2010-01-01

    Appetite, food intake, and energy balance are closely linked to the endocannabinoid system in the central nervous system. Now, endocannabinoid modulation has been discovered in the peripheral olfactory system of larval Xenopus laevis. The endocannabinoid 2-AG has been shown to influence odorant-detection thresholds according to the hunger state of the animal. Hungry animals have increased 2-AG levels due to enhanced synthesis of 2-AG in sustentacular supporting cells. This renders olfactory receptor neurons, exhibiting CB1 receptors, more sensitive at detecting lower odorant concentrations, which probably helps the animal to locate food. Since taste and vision are also influenced by endocannabinoids, this kind of modulation might boost sensory inputs of food in hungry animals.

  5. Odors Discrimination by Olfactory Epithelium Biosensor

    NASA Astrophysics Data System (ADS)

    Liu, Qingjun; Hu, Ning; Ye, Weiwei; Zhang, Fenni; Wang, Hua; Wang, Ping

    2011-09-01

    Humans are exploring the bionic biological olfaction to sense the various trace components of gas or liquid in many fields. For achieving the goal, we endeavor to establish a bioelectronic nose system for odor detection by combining intact bioactive function units with sensors. The bioelectronic nose is based on the olfactory epithelium of rat and microelectrode array (MEA). The olfactory epithelium biosensor generates extracellular potentials in presence of odor, and presents obvious specificity under different odors condition. The odor response signals can be distinguished with each other effectively by signal sorting. On basis of bioactive MEA hybrid system and the improved signal processing analysis, the bioelectronic nose will realize odor discrimination by the specific feature of signals response to various odors.

  6. Olfactory pathogenesis of idiopathic Parkinson disease revisited.

    PubMed

    Lerner, Alicja; Bagic, Anto

    2008-06-15

    Idiopathic Parkinson disease (PD) is traditionally considered a movement disorder with hallmark lesions located in the substantia nigra pars compacta (SNpc). However, recent histopathological studies of some PD cases suggest the possibility of a multisystem disorder which progresses in a predictable sequence as described in Braak's staging criteria. The disease process starts in the dorsal motor nucleus of the vagus (dmX) and anterior olfactory nucleus and bulb, and from there, spreads through the brainstem nuclei to ultimately reach the SNpc, which then presents as symptomatic PD. In this article, we would like to revisit the olfactory pathogenesis of PD based on Braak's staging system and review anatomical pathways supporting such a possibility. We also suggest some biomarkers for early stages of PD. Additionally, we present and discuss the possibility that a prion-like process underlies the neurodegenerative changes in PD.

  7. Olfactory Stimuli Increase Presence in Virtual Environments

    PubMed Central

    Munyan, Benson G.; Neer, Sandra M.; Beidel, Deborah C.; Jentsch, Florian

    2016-01-01

    Background Exposure therapy (EXP) is the most empirically supported treatment for anxiety and trauma-related disorders. EXP consists of repeated exposure to a feared object or situation in the absence of the feared outcome in order to extinguish associated anxiety. Key to the success of EXP is the need to present the feared object/event/situation in as much detail and utilizing as many sensory modalities as possible, in order to augment the sense of presence during exposure sessions. Various technologies used to augment the exposure therapy process by presenting multi-sensory cues (e.g., sights, smells, sounds). Studies have shown that scents can elicit emotionally charged memories, but no prior research has examined the effect of olfactory stimuli upon the patient’s sense of presence during simulated exposure tasks. Methods 60 adult participants navigated a mildly anxiety-producing virtual environment (VE) similar to those used in the treatment of anxiety disorders. Participants had no autobiographical memory associated with the VE. State anxiety, Presence ratings, and electrodermal (EDA) activity were collected throughout the experiment. Results Utilizing a Bonferroni corrected Linear Mixed Model, our results showed statistically significant relationships between olfactory stimuli and presence as assessed by both the Igroup Presence Questionnaire (IPQ: R2 = 0.85, (F(3,52) = 6.625, p = 0.0007) and a single item visual-analogue scale (R2 = 0.85, (F(3,52) = 5.382, p = 0.0027). State anxiety was unaffected by the presence or absence of olfactory cues. EDA was unaffected by experimental condition. Conclusion Olfactory stimuli increase presence in virtual environments that approximate those typical in exposure therapy, but did not increase EDA. Additionally, once administered, the removal of scents resulted in a disproportionate decrease in presence. Implications for incorporating the use of scents to increase the efficacy of exposure therapy is discussed. PMID

  8. Descriptive epidemiology of selected olfactory tumors.

    PubMed

    Villano, J Lee; Bressler, Linda; Propp, Jennifer M; Valyi-Nagy, Tibor; Martin, Iman K; Dolecek, Therese A; McCarthy, Bridget J

    2010-10-01

    Olfactory tumors, especially olfactory neuroblastomas (ON) and carcinomas with neuroendocrine differentiation (CND), are extremely rare, and little descriptive epidemiologic information is available. The objective of this study was to more fully describe selected olfactory tumors using a large population-based cancer incidence database. The Surveillance, Epidemiology and End Results (SEER) 9 registries limited-use data were reviewed from 1973 to 2006 for selected nasal cavity (C30.0) and accessory sinus (C31.0-31.9) tumors. Frequencies, incidence rates, and relative survival rates were estimated using SEER*Stat, v6.5.2. The majority of cases were squamous cell carcinoma (SCC), while the incidence of ON was greater than CND. For ON, the incidence was highest in the 60-79 year age group, while for SCC, the incidence was highest in the 80+ year age group. For CND, the incidence leveled off in the oldest age groups. Survival rates were highest for ON (>70% alive at 5 years after diagnosis) and poorest for CND (44% alive at 5 years). Adjuvant radiation therapy did not improve survival over surgery alone in ON. In SCC, survival was worse in patients who received adjuvant radiation compared to patients who had surgery alone. Our analysis confirms some previously published information, and adds new information about the incidence and demographics of ON and CND. In addition, our analysis documents the lack of benefit of adjuvant radiation in ON. It is not feasible to conduct prospective trials in patients with these rare diseases, and the importance of registry data in learning about olfactory tumors is emphasized.

  9. Neurally Encoding Time for Olfactory Navigation

    PubMed Central

    Park, In Jun; Hein, Andrew M.; Bobkov, Yuriy V.; Reidenbach, Matthew A.; Ache, Barry W.; Principe, Jose C.

    2016-01-01

    Accurately encoding time is one of the fundamental challenges faced by the nervous system in mediating behavior. We recently reported that some animals have a specialized population of rhythmically active neurons in their olfactory organs with the potential to peripherally encode temporal information about odor encounters. If these neurons do indeed encode the timing of odor arrivals, it should be possible to demonstrate that this capacity has some functional significance. Here we show how this sensory input can profoundly influence an animal’s ability to locate the source of odor cues in realistic turbulent environments—a common task faced by species that rely on olfactory cues for navigation. Using detailed data from a turbulent plume created in the laboratory, we reconstruct the spatiotemporal behavior of a real odor field. We use recurrence theory to show that information about position relative to the source of the odor plume is embedded in the timing between odor pulses. Then, using a parameterized computational model, we show how an animal can use populations of rhythmically active neurons to capture and encode this temporal information in real time, and use it to efficiently navigate to an odor source. Our results demonstrate that the capacity to accurately encode temporal information about sensory cues may be crucial for efficient olfactory navigation. More generally, our results suggest a mechanism for extracting and encoding temporal information from the sensory environment that could have broad utility for neural information processing. PMID:26730727

  10. Functional neuroanatomy of Drosophila olfactory memory formation

    PubMed Central

    Guven-Ozkan, Tugba

    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 extending from the site(s) of acquisition to the site(s) controlling memory expression? (3) How is information processed across this circuit to consolidate early-forming, disruptable memories to stable, late memories? Much progress has been made and a few strong conclusions have emerged: (1) Acquisition occurs at multiple sites within the olfactory nervous system but is mediated predominantly by the γ mushroom body neurons. (2) The expression of long-term memory is completely dependent on the synaptic output of α/β mushroom body neurons. (3) Consolidation occurs, in part, through circuit interactions between mushroom body and dorsal paired medial neurons. Despite this progress, a complete and unified model that details the pathway from acquisition to memory expression remains elusive. PMID:25225297

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

    PubMed

    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.

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

    PubMed Central

    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

  13. Syndrome of inappropriate antidiuretic hormone secretion associated with olfactory neuroblastoma.

    PubMed

    Yumusakhuylu, Ali Cemal; Binnetoglu, Adem; Topuz, Muhammet Fatih; Bozkurtlar, Emine Baş; Baglam, Tekin; Sari, Murat

    2013-11-01

    This study reports a patient having olfactory neuroblastoma complicated by syndrome of inappropriate antidiuretic hormone secretion. Olfactory neuroblastoma is a rare tumor that begins in the olfactory membrane. Only 10 cases have been reported previously. Because of having nonspecific symptoms, most patients manifest at an advanced stage at the time of diagnosis. Olfactory neuroblastoma may show local invasion and/or distant metastasis. We demonstrated preoperatively clinical and biochemical parameters consistent with antidiuretic hormone syndrome turned to normal ranges after the treatment. Surgery, chemotherapy, and radiotherapy are the choices of treatment; among these, surgery is an indispensible treatment.

  14. Zonal organization of the mammalian main and accessory olfactory systems.

    PubMed Central

    Mori, K; von Campenhause, H; Yoshihara, Y

    2000-01-01

    Zonal organization is one of the characteristic features observed in both main and accessory olfactory systems. In the main olfactory system, most of the odorant receptors are classified into four groups according to their zonal expression patterns in the olfactory epithelium. Each group of odorant receptors is expressed by sensory neurons distributed within one of four circumscribed zones. Olfactory sensory neurons in a given zone of the epithelium project their axons to the glomeruli in a corresponding zone of the main olfactory bulb. Glomeruli in the same zone tend to represent similar odorant receptors having similar tuning specificity to odorants. Vomeronasal receptors (or pheromone receptors) are classified into two groups in the accessory olfactory system. Each group of receptors is expressed by vomeronasal sensory neurons in either the apical or basal zone of the vomeronasal epithelium. Sensory neurons in the apical zone project their axons to the rostral zone of the accessory olfactory bulb and form synaptic connections with mitral tufted cells belonging to the rostral zone. Signals originated from basal zone sensory neurons are sent to mitral tufted cells in the caudal zone of the accessory olfactory bulb. We discuss functional implications of the zonal organization in both main and accessory olfactory systems. PMID:11205342

  15. Feedback from network states generates variability in a probabilistic olfactory circuit

    PubMed Central

    Gordus, Andrew; Pokala, Navin; Levy, Sagi; Flavell, Steven W.; Bargmann, Cornelia I

    2016-01-01

    Summary Variability is a prominent feature of behavior, and an active element of certain behavioral strategies. To understand how neuronal circuits control variability, we examined the propagation of sensory information in a chemotaxis circuit of Caenorhabditis elegans where discrete sensory inputs can drive a probabilistic behavioral response. Olfactory neurons respond to odor stimuli with rapid and reliable changes in activity, but downstream AIB interneurons respond with a probabilistic delay. The interneuron response to odor depends on the collective activity of multiple neurons – AIB, RIM, and AVA -- when the odor stimulus arrives. Certain activity states of the network correlate with reliable responses to odor stimuli. Artificially generating these activity states by modifying neuronal activity increases the reliability of odor responses in interneurons and the reliability of the behavioral response to odor. The integration of sensory information with network state may represent a general mechanism for generating variability in behavior. PMID:25772698

  16. Pulse Width Modulation Applied to Olfactory Stimulation for Intensity Tuning.

    PubMed

    Andrieu, Patrice; Billot, Pierre-Édouard; Millot, Jean-Louis; Gharbi, Tijani

    2015-01-01

    For most olfactometers described in the literature, adjusting olfactory stimulation intensity involves modifying the dilution of the odorant in a neutral solution (water, mineral, oil, etc.), the dilution of the odorant air in neutral airflow, or the surface of the odorant in contact with airflow. But, for most of these above-mentioned devices, manual intervention is necessary for adjusting concentration. We present in this article a method of controlling odorant concentration via a computer which can be implemented on even the most dynamic olfactometers. We used Pulse Width Modulation (PWM), a technique commonly used in electronic or electrical engineering, and we have applied it to odor delivery. PWM, when applied to odor delivery, comprises an alternative presentation of odorant air and clean air at a high frequency. The cycle period (odor presentation and rest) is 200 ms. In order to modify odorant concentration, the ratio between the odorant period and clean air presentation during a cycle is modified. This ratio is named duty cycle. Gas chromatography measurements show that this method offers a range of mixing factors from 33% to 100% (continuous presentation of odor). Proof of principle is provided via a psychophysical experiment. Three odors (isoamyl acetate, butanol and pyridine) were presented to twenty subjects. Each odor was delivered three times with five values of duty cycles. After each stimulation, the subjects were asked to estimate the intensity of the stimulus on a 10 point scale, ranging from 0 (undetectable) to 9 (very strong). Results show a main effect of the duty cycles on the intensity ratings for all tested odors.

  17. Application of the European Test of Olfactory Capabilities in patients with olfactory impairment.

    PubMed

    Joussain, P; Bessy, M; Faure, F; Bellil, D; Landis, B N; Hugentobler, M; Tuorila, H; Mustonen, S; Vento, S I; Delphin-Combe, F; Krolak-Salmon, P; Rouby, C; Bensafi, M

    2016-02-01

    A central issue in olfaction concerns the characterization of loss of olfactory function: partial (hyposmia) or total (anosmia). This paper reports the application in a clinical setting of the European Test of Olfactory Capabilities (ETOC), combining odor detection and identification. The study included three phases. In phase 1, anosmics, hyposmics and controls were tested with the 16-items version of the ETOC. In phase 2, a short version of the ETOC was developed: patients with and controls without olfactory impairment were tested on a 6-items ETOC. In phase 3, to predict olfactory impairments in new individuals, the 16-items ETOC was administered on samples of young and older adults, and the 6-items version was applied in samples of young, elderly participants and Alzheimer patients. In phase 1, linear discriminant analysis (LDA) of ETOC scores classified patients and controls with 87.5 % accuracy. In phase 2, LDA provided 84 % correct classification. Results of phase 3 revealed: (1) 16-items ETOC: whereas in young adults, 10 % were classified as hyposmic and 90 % as normosmic, in elderly, 1 % were classified as anosmic, 39 % hyposmic and 60 % normosmic; (2) 6-items ETOC: 15 % of the young adults were classified as having olfactory impairment, compared to 28 % in the older group and 83 % in Alzheimer patients. In conclusion, the ETOC enables characterizing the prevalence of olfactory impairment in young subjects and in normal and pathological aging. Whereas the 16-items ETOC is more discriminant, the short ETOC may provide a fast (5-10 min) tool to assess olfaction in clinical settings.

  18. Impacts of upper respiratory tract disease on olfactory behavior of the Mojave desert tortoise.

    PubMed

    Germano, Jennifer; Van Zerr, Vanessa E; Esque, Todd C; Nussear, Ken E; Lamberski, Nadine

    2014-04-01

    Upper respiratory tract disease (URTD) caused by Mycoplasma agassizii is considered a threat to desert tortoise populations that should be addressed as part of the recovery of the species. Clinical signs can be intermittent and include serous or mucoid nasal discharge and respiratory difficulty when nares are occluded. This nasal congestion may result in a loss of the olfactory sense. Turtles are known to use olfaction to identify food items, predators, and conspecifics; therefore, it is likely that URTD affects not only their physical well-being but also their behavior and ability to perform necessary functions in the wild. To determine more specifically the impact nasal discharge might have on free-ranging tortoises (Gopherus agassizii), we compared the responses of tortoises with and without nasal discharge and both positive and negative for M. agassizii antibodies to a visually hidden olfactory food stimulus and an empty control. We found that nasal discharge did reduce sense of smell and hence the ability to locate food. Our study also showed that moderate chronic nasal discharge in the absence of other clinical signs did not affect appetite in desert tortoises.

  19. An Investigation on the Role of Spike Latency in an Artificial Olfactory System

    PubMed Central

    Martinelli, Eugenio; Polese, Davide; Dini, Francesca; Paolesse, Roberto; Filippini, Daniel; Lundström, Ingemar; Di Natale, Corrado

    2011-01-01

    Experimental studies have shown that the reactions to external stimuli may appear only few hundreds of milliseconds after the physical interaction of the stimulus with the proper receptor. This behavior suggests that neurons transmit the largest meaningful part of their signal in the first spikes, and than that the spike latency is a good descriptor of the information content in biological neural networks. In this paper this property has been investigated in an artificial sensorial system where a single layer of spiking neurons is trained with the data generated by an artificial olfactory platform based on a large array of chemical sensors. The capability to discriminate between distinct chemicals and mixtures of them was studied with spiking neural networks endowed with and without lateral inhibitions and considering as output feature of the network both the spikes latency and the average firing rate. Results show that the average firing rate of the output spikes sequences shows the best separation among the experienced vapors, however the latency code is able in a shorter time to correctly discriminate all the tested volatile compounds. This behavior is qualitatively similar to those recently found in natural olfaction, and noteworthy it provides practical suggestions to tail the measurement conditions of artificial olfactory systems defining for each specific case a proper measurement time. PMID:22194721

  20. Impacts of upper respiratory tract disease on olfactory behavior of the Mojave desert tortoise

    USGS Publications Warehouse

    Germano, Jennifer; Van Zerr, Vanessa E.; Esque, Todd C.; Nussear, Ken E.; Lamberski, Nadine

    2014-01-01

    Upper respiratory tract disease (URTD) caused by Mycoplasma agassizii is considered a threat to desert tortoise populations that should be addressed as part of the recovery of the species. Clinical signs can be intermittent and include serous or mucoid nasal discharge and respiratory difficulty when nares are occluded. This nasal congestion may result in a loss of the olfactory sense. Turtles are known to use olfaction to identify food items, predators, and conspecifics; therefore, it is likely that URTD affects not only their physical well-being but also their behavior and ability to perform necessary functions in the wild. To determine more specifically the impact nasal discharge might have on free-ranging tortoises (Gopherus agassizii), we compared the responses of tortoises with and without nasal discharge and both positive and negative for M. agassizii antibodies to a visually hidden olfactory food stimulus and an empty control. We found that nasal discharge did reduce sense of smell and hence the ability to locate food. Our study also showed that moderate chronic nasal discharge in the absence of other clinical signs did not affect appetite in desert tortoises.

  1. Visual and olfactory associative learning in the malaria vector Anopheles gambiae sensu stricto

    PubMed Central

    2012-01-01

    Background Memory and learning are critical aspects of the ecology of insect vectors of human pathogens because of their potential effects on contacts between vectors and their hosts. Despite this epidemiological importance, there have been only a limited number of studies investigating associative learning in insect vector species and none on Anopheline mosquitoes. Methods A simple behavioural assays was developed to study visual and olfactory associative learning in Anopheles gambiae, the main vector of malaria in Africa. Two contrasted membrane qualities or levels of blood palatability were used as reinforcing stimuli for bi-directional conditioning during blood feeding. Results Under such experimental conditions An. gambiae females learned very rapidly to associate visual (chequered and white patterns) and olfactory cues (presence and absence of cheese or Citronella smell) with the reinforcing stimuli (bloodmeal quality) and remembered the association for up to three days. Associative learning significantly increased with the strength of the conditioning stimuli used. Importantly, learning sometimes occurred faster when a positive reinforcing stimulus (palatable blood) was associated with an innately preferred cue (such as a darker visual pattern). However, the use of too attractive a cue (e.g. Shropshire cheese smell) was counter-productive and decreased learning success. Conclusions The results address an important knowledge gap in mosquito ecology and emphasize the role of associative memory for An. gambiae's host finding and blood-feeding behaviour with important potential implications for vector control. PMID:22284012

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

    PubMed Central

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

    2016-01-01

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

  3. Odour-modulated collective network oscillations of olfactory interneurons in a terrestrial mollusc

    NASA Astrophysics Data System (ADS)

    Gelperin, Alan; Tank, David W.

    1990-05-01

    DETERMINATION of the dynamical structure of neural circuits—the general principles of how neural activity varies with time and manipulates information—is a prerequisite to understanding their computational function1. Rhythmically active or oscillating neural circuits are particularly interesting dynamical structures, as rhythms and oscillations are a prominent feature of mammalian central nervous system electrophysiology. Coherent oscillations by networks of interneurons are observed in the vertebrate olfactory system2,3 and have recently been described in mammalian visual cortex4-6. These interneuronal networks display oscillations in local field potential (LFP) and probability of producing action potentials that are highly correlated between subcircuits sharing the same stimulus features. Much less is known about the existence and importance of network oscillations in the higher centres of invertebrates7. Here we report that a network of olfactory inter-neurons in the cerebral ganglion of the terrestrial mollusc Limax maximus also displays coherent oscillations in LFP which are modified by odour input. This dynamical structure could be central to the odour recognition and odour learning ability of Limax8,9.

  4. Appetitive but not aversive olfactory conditioning modifies antennal movements in honeybees.

    PubMed

    Cholé, Hanna; Junca, Pierre; Sandoz, Jean-Christophe

    2015-12-01

    In honeybees, two olfactory conditioning protocols allow the study of appetitive and aversive Pavlovian associations. Appetitive conditioning of the proboscis extension response (PER) involves associating an odor, the conditioned stimulus (CS) with a sucrose solution, the unconditioned stimulus (US). Conversely, aversive conditioning of the sting extension response (SER) involves associating the odor CS with an electric or thermal shock US. Each protocol is based on the measure of a different behavioral response (proboscis versus sting) and both only provide binary responses (extension or not of the proboscis or sting). These limitations render the measure of the acquired valence of an odor CS difficult without testing the animals in a freely moving situation. Here, we studied the effects of both olfactory conditioning protocols on the movements of the antennae, which are crucial sensory organs for bees. As bees' antennae are highly mobile, we asked whether their movements in response to an odorant change following appetitive or aversive conditioning and if so, do odor-evoked antennal movements contain information about the acquired valence of the CS? We implemented a tracking system for harnessed bees' antennal movements based on a motion capture principle at a high frequency rate. We observed that differential appetitive conditioning had a strong effect on antennal movements. Bees responded to the reinforced odorant with a marked forward motion of the antennae and a strong velocity increase. Conversely, differential aversive conditioning had no associative effect on antennal movements. Rather than revealing the acquired valence of an odorant, antennal movements may represent a novel conditioned response taking place during appetitive conditioning and may provide a possible advantage to bees when foraging in natural situations.

  5. Appetitive but not aversive olfactory conditioning modifies antennal movements in honeybees

    PubMed Central

    Cholé, Hanna; Junca, Pierre

    2015-01-01

    In honeybees, two olfactory conditioning protocols allow the study of appetitive and aversive Pavlovian associations. Appetitive conditioning of the proboscis extension response (PER) involves associating an odor, the conditioned stimulus (CS) with a sucrose solution, the unconditioned stimulus (US). Conversely, aversive conditioning of the sting extension response (SER) involves associating the odor CS with an electric or thermal shock US. Each protocol is based on the measure of a different behavioral response (proboscis versus sting) and both only provide binary responses (extension or not of the proboscis or sting). These limitations render the measure of the acquired valence of an odor CS difficult without testing the animals in a freely moving situation. Here, we studied the effects of both olfactory conditioning protocols on the movements of the antennae, which are crucial sensory organs for bees. As bees’ antennae are highly mobile, we asked whether their movements in response to an odorant change following appetitive or aversive conditioning and if so, do odor-evoked antennal movements contain information about the acquired valence of the CS? We implemented a tracking system for harnessed bees’ antennal movements based on a motion capture principle at a high frequency rate. We observed that differential appetitive conditioning had a strong effect on antennal movements. Bees responded to the reinforced odorant with a marked forward motion of the antennae and a strong velocity increase. Conversely, differential aversive conditioning had no associative effect on antennal movements. Rather than revealing the acquired valence of an odorant, antennal movements may represent a novel conditioned response taking place during appetitive conditioning and may provide a possible advantage to bees when foraging in natural situations. PMID:26572651

  6. The olfactory apparatus of the bandicoot (Isoodon macrourus): fine structure and presence of a septal olfactory organ.

    PubMed Central

    Kratzing, J E

    1978-01-01

    The structure and extent of olfactory epithelium in the bandicoot (Isoodon macrourus) were examined by light and electron microscopy. Sensory epithelium covers most of the dorsal conchae, though non-sensory epithelium lines ventrally facing scrolls. The middle conchae are partly covered by olfactory epithelium, the proportion of olfactory to ciliated respiratory epithelium increasing caudally. Ventral conchae are lined by non-sensory ciliated epithelium. The nasal septum ends short of the floor of the nasal cavity in its caudal two thirds. It is covered dorsally by olfactory epithelium. The ventral margin has rounded lateral extensions which carry the isolated strips of olfactory epithelium which form the septal olfactory organ. The fine structure of the olfactory epithelium is the same in all areas. Cell types include olfactory receptors, supporting cells, two types of basal cell and rarer pale and brush cells. There is considerable morphological variation in olfactory cells, and evidence suggestive of continuing turnover in the receptor cell population. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9 PMID:640961

  7. Focal uncaging of GABA reveals a temporally defined role for GABAergic inhibition during appetitive associative olfactory conditioning in honeybees.

    PubMed

    Raccuglia, Davide; Mueller, Uli

    2013-07-16

    Throughout the animal kingdom, the inhibitory neurotransmitter γ-aminobutyric acid (GABA) is a key modulator of physiological processes including learning. With respect to associative learning, the exact time in which GABA interferes with the molecular events of learning has not yet been clearly defined. To address this issue, we used two different approaches to activate GABA receptors during appetitive olfactory conditioning in the honeybee. Injection of GABA-A receptor agonist muscimol 20 min before but not 20 min after associative conditioning affects memory performance. These memory deficits were attenuated by additional training sessions. Muscimol has no effect on sensory perception, odor generalization, and nonassociative learning, indicating a specific role of GABA during associative conditioning. We used photolytic uncaging of GABA to identify the GABA-sensitive time window during the short pairing of the conditioned stimulus (CS) and the unconditioned stimulus (US) that lasts only seconds. Either uncaging of GABA in the antennal lobes or the mushroom bodies during the CS presentation of the CS-US pairing impairs memory formation, while uncaging GABA during the US phase has no effect on memory. Uncaging GABA during the CS presentation in memory retrieval also has no effect. Thus, in honeybee appetitive olfactory learning GABA specifically interferes with the integration of CS and US during associative conditioning and exerts a modulatory role in memory formation depending on the training strength.

  8. Sample Stimulus Control Shaping and Restricted Stimulus Control in Capuchin Monkeys: A Methodological Note

    ERIC Educational Resources Information Center

    Brino, Ana Leda F., Barros, Romariz S., Galvao, Ol; Garotti, M.; Da Cruz, Ilara R. N.; Santos, Jose R.; Dube, William V.; McIlvane, William J.

    2011-01-01

    This paper reports use of sample stimulus control shaping procedures to teach arbitrary matching-to-sample to 2 capuchin monkeys ("Cebus apella"). The procedures started with identity matching-to-sample. During shaping, stimulus features of the sample were altered gradually, rendering samples and comparisons increasingly physically dissimilar. The…

  9. Emergent Stimulus Relations Depend on Stimulus Correlation and Not on Reinforcement Contingencies

    ERIC Educational Resources Information Center

    Minster, Sara Tepaeru; Elliffe, Douglas; Muthukumaraswamy, Suresh D.

    2011-01-01

    We aimed to investigate whether novel stimulus relations would emerge from stimulus correlations when those relations explicitly conflicted with reinforced relations. In a symbolic matching-to-sample task using kanji characters as stimuli, we arranged class-specific incorrect comparison stimuli in each of three classes. After presenting either Ax…

  10. Stimulus-responsive metal-organic frameworks.

    PubMed

    Nagarkar, Sanjog S; Desai, Aamod V; Ghosh, Sujit K

    2014-09-01

    Materials that can recognize the changes in their local environment and respond by altering their inherent physical and/or chemical properties are strong candidates for future "smart" technology materials. Metal-organic frameworks (MOFs) have attracted a great deal of attention in recent years owing to their designable architecture, host-guest chemistry, and softness as porous materials. Despite this fact, studies on the tuning of the properties of MOFs by external stimuli are still rare. This review highlights the recent developments in the field of stimulus-responsive MOFs or so-called smart MOFs. In particular, the various stimuli used and the utility of stimulus-responsive smart MOFs for various applications such as gas storage and separation, sensing, clean energy, catalysis, molecular motors, and biomedical applications are highlighted by using representative examples. Future directions in the developments of stimulus-responsive smart MOFs and their applications are proposed from a personal perspective.

  11. Impact of stimulus uncanniness on speeded response.

    PubMed

    Takahashi, Kohske; Fukuda, Haruaki; Samejima, Kazuyuki; Watanabe, Katsumi; Ueda, Kazuhiro

    2015-01-01

    In the uncanny valley phenomenon, the causes of the feeling of uncanniness as well as the impact of the uncanniness on behavioral performances still remain open. The present study investigated the behavioral effects of stimulus uncanniness, particularly with respect to speeded response. Pictures of fish were used as visual stimuli. Participants engaged in direction discrimination, spatial cueing, and dot-probe tasks. The results showed that pictures rated as strongly uncanny delayed speeded response in the discrimination of the direction of the fish. In the cueing experiment, where a fish served as a task-irrelevant and unpredictable cue for a peripheral target, we again observed that the detection of a target was slowed when the cue was an uncanny fish. Conversely, the dot-probe task suggested that uncanny fish, unlike threatening stimulus, did not capture visual spatial attention. These results suggested that stimulus uncanniness resulted in the delayed response, and importantly this modulation was not mediated by the feelings of threat.

  12. Contributions to drug abuse research of Steven R. Goldberg's behavioral analysis of stimulus-stimulus contingencies.

    PubMed

    Katz, Jonathan L

    2016-05-01

    By the mid-1960s, the concept that drugs can function as reinforcing stimuli through response-reinforcer contingencies had created a paradigm shift in drug abuse science. Steve Goldberg's first several publications focused instead on stimulus-stimulus contingencies (respondent conditioning) in examining Abraham Wikler's two-factor hypothesis of relapse involving conditioned withdrawal and reinforcing effects of drugs. Goldberg provided a compelling demonstration that histories of contingencies among stimuli could produce lasting withdrawal reactions in primates formerly dependent on opioids. Other studies conducted by Goldberg extended the analysis of effects of stimulus-stimulus contingencies on behavior maintained by opioid reinforcing effects and showed that withdrawal-inducing antagonist administration can produce conditioned increases in self-administration. Subsequent studies of the effects of stimuli associated with cocaine injection under second-order schedules showed that the maintenance of behavior with drug injections was in most important aspects similar to the maintenance of behavior with more conventional reinforcers when the behavior-disrupting pharmacological effects of the drugs were minimized. Studies on second-order schedules demonstrated a wide array of conditions under which behavior could be maintained by drug injection and further influenced by stimulus-stimulus contingencies. These schedules present opportunities to produce in the laboratory complex situations involving response- and stimulus-stimulus contingencies, which go beyond simplistic pairings of stimuli and more closely approximate those found with human drug abusers. A focus on the response- and stimulus-stimulus contingencies, and resulting quantifiable changes in objective and quantifiable behavioral endpoints exemplified by the studies by Steve Goldberg, remains the most promising way forward for studying problems of drug dependence.

  13. A Screen for Genes Expressed in the Olfactory Organs of Drosophila melanogaster Identifies Genes Involved in Olfactory Behaviour

    PubMed Central

    Tunstall, Narelle E.; Herr, Anabel; de Bruyne, Marien; Warr, Coral G.

    2012-01-01

    Background For insects the sense of smell and associated olfactory-driven behaviours are essential for survival. Insects detect odorants with families of olfactory receptor proteins that are very different to those of mammals, and there are likely to be other unique genes and genetic pathways involved in the function and development of the insect olfactory system. Methodology/Principal Findings We have performed a genetic screen of a set of 505 Drosophila melanogaster gene trap insertion lines to identify novel genes expressed in the adult olfactory organs. We identified 16 lines with expression in the olfactory organs, many of which exhibited expression of the trapped genes in olfactory receptor neurons. Phenotypic analysis showed that six of the lines have decreased olfactory responses in a behavioural assay, and for one of these we showed that precise excision of the P element reverts the phenotype to wild type, confirming a role for the trapped gene in olfaction. To confirm the identity of the genes trapped in the lines we performed molecular analysis of some of the insertion sites. While for many lines the reported insertion sites were correct, we also demonstrated that for a number of lines the reported location of the element was incorrect, and in three lines there were in fact two pGT element insertions. Conclusions/Significance We identified 16 new genes expressed in the Drosophila olfactory organs, the majority in neurons, and for several of the gene trap lines demonstrated a defect in olfactory-driven behaviour. Further characterisation of these genes and their roles in olfactory system function and development will increase our understanding of how the insect olfactory system has evolved to perform the same essential function to that of mammals, but using very different molecular genetic mechanisms. PMID:22530061

  14. Neuropeptide S facilitates mice olfactory function through activation of cognate receptor-expressing neurons in the olfactory cortex.

    PubMed

    Shao, Yu-Feng; Zhao, Peng; Dong, Chao-Yu; Li, Jing; Kong, Xiang-Pan; Wang, Hai-Liang; Dai, Li-Rong; Hou, Yi-Ping

    2013-01-01

    Neuropeptide S (NPS) is a newly identified neuromodulator located in the brainstem and regulates various biological functions by selectively activating the NPS receptors (NPSR). High level expression of NPSR mRNA in the olfactory cortex suggests that NPS-NPSR system might be involved in the regulation of olfactory function. The present study was undertaken to investigate the effects of intracerebroventricular (i.c.v.) injection of NPS or co-injection of NPSR antagonist on the olfactory behaviors, food intake, and c-Fos expression in olfactory cortex in mice. In addition, dual-immunofluorescence was employed to identify NPS-induced Fos immunereactive (-ir) neurons that also bear NPSR. NPS (0.1-1 nmol) i.c.v. injection significantly reduced the latency to find the buried food, and increased olfactory differentiation of different odors and the total sniffing time spent in olfactory habituation/dishabituation tasks. NPS facilitated olfactory ability most at the dose of 0.5 nmol, which could be blocked by co-injection of 40 nmol NPSR antagonist [D-Val(5)]NPS. NPS administration dose-dependently inhibited food intake in fasted mice. Ex-vivo c-Fos and NPSR immunohistochemistry in the olfactory cortex revealed that, as compared with vehicle-treated mice, NPS markedly enhanced c-Fos expression in the anterior olfactory nucleus (AON), piriform cortex (Pir), ventral tenia tecta (VTT), the anterior cortical amygdaloid nucleus (ACo) and lateral entorhinal cortex (LEnt). The percentage of Fos-ir neurons that also express NPSR were 88.5% and 98.1% in the AON and Pir, respectively. The present findings demonstrated that NPS, via selective activation of the neurons bearing NPSR in the olfactory cortex, facilitates olfactory function in mice.

  15. Dietary sodium protects fish against copper-induced olfactory impairment.

    PubMed

    Azizishirazi, Ali; Dew, William A; Bougas, Berenice; Bernatchez, Louis; Pyle, Greg G

    2015-04-01

    Exposure to low concentrations of copper impairs olfaction in fish. To determine the transcriptional changes in the olfactory epithelium induced by copper exposure, wild yellow perch (Perca flavescens) were exposed to 20 μg/L of copper for 3 and 24h. A novel yellow perch microarray with 1000 candidate genes was used to measure differential gene transcription in the olfactory epithelium. While three hours of exposure to copper changed the transcription of only one gene, the transcriptions of 70 genes were changed after 24h of exposure to copper. Real-time PCR was utilized to determine the effect of exposure duration on two specific genes of interest, two sub-units of Na/K-ATPase. At 24 and 48 h, Na/K-ATPase transcription was down-regulated by copper at olfactory rosettes. As copper-induced impairment of Na/K-ATPase activity in gills can be ameliorated by increased dietary sodium, rainbow trout (Oncorhynchus mykiss) were used to determine if elevated dietary sodium was also protective against copper-induced olfactory impairment. Measurement of the olfactory response of rainbow trout using electro-olfactography demonstrated that sodium was protective of copper-induced olfactory dysfunction. This work demonstrates that the transcriptions of both subunits of Na/K-ATPase in the olfactory epithelium of fish are affected by Cu exposure, and that dietary Na protects against Cu-induced olfactory dysfunction.

  16. Forward and Back: Motifs of Inhibition in Olfactory Processing

    PubMed Central

    Bazhenov, Maxim; Stopfer, Mark

    2016-01-01

    The remarkable performance of the olfactory system in classifying and categorizing the complex olfactory environment is built upon several basic neural circuit motifs. These include forms of inhibition that may play comparable roles in widely divergent species. In this issue of Neuron, a new study by Stokes and Isaacson sheds light on how elementary types of inhibition dynamically interact. PMID:20696373

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

    ERIC Educational Resources Information Center

    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…

  18. 21 CFR 874.1600 - Olfactory test device.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Olfactory test device. 874.1600 Section 874.1600 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Diagnostic Devices § 874.1600 Olfactory test device....

  19. 21 CFR 874.1600 - Olfactory test device.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Olfactory test device. 874.1600 Section 874.1600 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Diagnostic Devices § 874.1600 Olfactory test device....

  20. 21 CFR 874.1600 - Olfactory test device.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Olfactory test device. 874.1600 Section 874.1600 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Diagnostic Devices § 874.1600 Olfactory test device....

  1. The Odorant Receptor-Dependent Role of Olfactory Marker Protein in Olfactory Receptor Neurons

    PubMed Central

    Dibattista, Michele

    2016-01-01

    Olfactory receptor neurons (ORNs) in the nasal cavity detect and transduce odorants into action potentials to be conveyed to the olfactory bulb. Odorants are delivered to ORNs via the inhaled air at breathing frequencies that can vary from 2 to 10 Hz in the mouse. Thus olfactory transduction should occur at sufficient speed such that it can accommodate repetitive and frequent stimulation. Activation of odorant receptors (ORs) leads to adenylyl cyclase III activation, cAMP increase, and opening of cyclic nucleotide-gated channels. This makes the kinetic regulation of cAMP one of the important determinants for the response time course. We addressed the dynamic regulation of cAMP during the odorant response and examined how basal levels of cAMP are controlled. The latter is particularly relevant as basal cAMP depends on the basal activity of the expressed OR and thus varies across ORNs. We found that olfactory marker protein (OMP), a protein expressed in mature ORNs, controls both basal and odorant-induced cAMP levels in an OR-dependent manner. Lack of OMP increases basal cAMP, thus abolishing differences in basal cAMP levels between ORNs expressing different ORs. Moreover, OMP speeds up signal transduction for ORNs to better synchronize their output with high-frequency stimulation and to perceive brief stimuli. Last, OMP also steepens the dose–response relation to improve concentration coding although at the cost of losing responses to weak stimuli. We conclude that OMP plays a key regulatory role in ORN physiology by controlling multiple facets of the odorant response. SIGNIFICANCE STATEMENT Odorant receptors (ORs) form the largest family of G-protein-coupled receptors in mammals and are expressed in olfactory receptor neurons (ORNs). In this paper we show how the olfactory system ensures that monogenic expression of ORs dictates the response profile and the basal noise of ORNs. Olfactory marker protein (OMP), a protein long known to be expressed in mature ORNs

  2. Viewing Olfactory Affective Responses Through the Sniff Prism: Effect of Perceptual Dimensions and Age on Olfactomotor Responses to Odors

    PubMed Central

    Ferdenzi, Camille; Fournel, Arnaud; Thévenet, Marc; Coppin, Géraldine; Bensafi, Moustafa

    2015-01-01

    Sniffing, which is the active sampling of olfactory information through the nasal cavity, is part of the olfactory percept. It is influenced by stimulus properties, affects how an odor is perceived, and is sufficient (without an odor being present) to activate the olfactory cortex. However, many aspects of the affective correlates of sniffing behavior remain unclear, in particular the modulation of volume and duration as a function of odor hedonics. The present study used a wide range of odorants with contrasted hedonic valence to test: (1) which psychophysical function best describes the relationship between sniffing characteristics and odor hedonics (e.g., linear, or polynomial); (2) whether sniffing characteristics are sensitive to more subtle variations in pleasantness than simple pleasant-unpleasant contrast; (3) how sensitive sniffing is to other perceptual dimensions of odors such as odor familiarity or edibility; and (4) whether the sniffing/hedonic valence relationship is valid in other populations than young adults, such as the elderly. Four experiments were conducted, using 16–48 odorants each, and recruiting a total of 102 participants, including a group of elderly people. Results of the four experiments were very consistent in showing that sniffing was sensitive to subtle variations in unpleasantness but not to subtle variations in pleasantness, and that, the more unpleasant the odor, the more limited the spontaneous sampling of olfactory information through the nasal cavity (smaller volume, shorter duration). This also applied, although to a lesser extent, to elderly participants. Relationships between sniffing and other perceptual dimensions (familiarity, edibility) were less clear. It was concluded that sniffing behavior might be involved in adaptive responses protecting the subject from possibly harmful substances. PMID:26635683

  3. The sensory channel of presentation alters subjective ratings and autonomic responses toward disgusting stimuli-Blood pressure, heart rate and skin conductance in response to visual, auditory, haptic and olfactory presented disgusting stimuli.

    PubMed

    Croy, Ilona; Laqua, Kerstin; Süß, Frank; Joraschky, Peter; Ziemssen, Tjalf; Hummel, Thomas

    2013-01-01

    Disgust causes specific reaction patterns, observable in mimic responses and body reactions. Most research on disgust deals with visual stimuli. However, pictures may cause another disgust experience than sounds, odors, or tactile stimuli. Therefore, disgust experience evoked by four different sensory channels was compared. A total of 119 participants received 3 different disgusting and one control stimulus, each presented through the visual, auditory, tactile, and olfactory channel. Ratings of evoked disgust as well as responses of the autonomic nervous system (heart rate, skin conductance level, systolic blood pressure) were recorded and the effect of stimulus labeling and of repeated presentation was analyzed. Ratings suggested that disgust could be evoked through all senses; they were highest for visual stimuli. However, autonomic reaction toward disgusting stimuli differed according to the channel of presentation. In contrast to the other, olfactory disgust stimuli provoked a strong decrease of systolic blood pressure. Additionally, labeling enhanced disgust ratings and autonomic reaction for olfactory and tactile, but not for visual and auditory stimuli. Repeated presentation indicated that participant's disgust rating diminishes to all but olfactory disgust stimuli. Taken together we argue that the sensory channel through which a disgust reaction is evoked matters.

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

    PubMed Central

    Larriva-Sahd, Jorge

    2012-01-01

    This study describes the microscopic organization of a wedge-shaped area at the intersection of the main (MOB) and accessory olfactory bulbs (AOBs), or olfactory limbus (OL), and an additional component of the anterior olfactory nucleus or alpha AON that lies underneath of the AOB. The OL consists of a modified bulbar cortex bounded anteriorly by the MOB and posteriorly by the AOB. In Nissl-stained specimens the OL differs from the MOB by a progressive, antero-posterior decrease in thickness or absence of the external plexiform, mitral/tufted cell, and granule cell layers. On cytoarchitectual grounds the OL is divided from rostral to caudal into three distinct components: a stripe of glomerular-free cortex or preolfactory area (PA), a second or necklace glomerular area, and a wedge-shaped or interstitial area (INA) crowned by the so-called modified glomeruli that appear to belong to the anterior AOB. The strategic location and interactions with the main and AOBs, together with the previously noted functional and connectional evidence, suggest that the OL may be related to both sensory modalities. The alpha component of the anterior olfactory nucleus, a slender cellular cluster (i.e., 650 × 150 μm) paralleling the base of the AOB, contains two neuron types: a pyramidal-like neuron and an interneuron. Dendrites of pyramidal-like cells (P-L) organize into a single bundle that ascends avoiding the AOB to resolve in a trigone bounded by the edge of the OL, the AOB and the dorsal part of the anterior olfactory nucleus. Utrastructurally, the neuropil of the alpha component contains three types of synaptic terminals; one of them immunoreactive to the enzyme glutamate decarboxylase, isoform 67. PMID:22754506

  5. Hidden consequences of olfactory dysfunction: a patient report series

    PubMed Central

    2013-01-01

    Background The negative consequences of olfactory dysfunction for the quality of life are not widely appreciated and the condition is therefore often ignored or trivialized. Methods 1,000 patients with olfactory dysfunction participated in an online study by submitting accounts of their subjective experiences of how they have been affected by their condition. In addition, they were given the chance to answer 43 specific questions about the consequences of their olfactory dysfunction. Results Although there are less practical problems associated with impaired or distorted odor perception than with impairments in visual or auditory perception, many affected individuals report experiencing olfactory dysfunction as a debilitating condition. Smell loss-induced social isolation and smell loss-induced anhedonia can severely affect quality of life. Conclusions Olfactory dysfunction is a serious condition for those affected by it and it deserves more attention from doctors who treat affected patients as well as from scientist who research treatment options. PMID:23875929

  6. Olfactory memory formation in Drosophila: from molecular to systems neuroscience.

    PubMed

    Davis, Ronald L

    2005-01-01

    The olfactory nervous system of insects and mammals exhibits many similarities, which suggests that the mechanisms for olfactory learning may be shared. Molecular genetic investigations of Drosophila learning have uncovered numerous genes whose gene products are essential for olfactory memory formation. Recent studies of the products of these genes have continued to expand the range of molecular processes known to underlie memory formation. Recent research has also broadened the neuroanatomical areas thought to mediate olfactory learning to include the antennal lobes in addition to a previously accepted and central role for the mushroom bodies. The roles for neurons extrinsic to the mushroom body neurons are becoming better defined. Finally, the genes identified to participate in Drosophila olfactory learning have conserved roles in mammalian organisms, highlighting the value of Drosophila for gene discovery.

  7. Carving Executive Control At Its Joints: Working Memory Capacity Predicts Stimulus-Stimulus, But Not Stimulus-Response, Conflict

    PubMed Central

    Meier, Matt E.; Kane, Michael J.

    2015-01-01

    Three experiments examined the relation between working memory capacity (WMC) and two different forms of cognitive conflict: stimulus-stimulus (S-S) and stimulus-response (SR) interference. Our goal was to test whether WMC’s relation to conflict-task performance is mediated by stimulus-identification processes (captured by S-S conflict), response-selection processes (captured by S-R conflict), or both. In Experiment 1, subjects completed a single task presenting both S-S and S-R conflict trials, plus trials that combined the two conflict types. We limited ostensible goal-maintenance contributions to performance by requiring the same goal for all trial types and by presenting frequent conflict trials that reinforced the goal. WMC predicted resolution of S-S conflict as expected: Higher-WMC subjects showed reduced response time interference. Although WMC also predicted S-R interference, here, higher-WMC subjects showed increased error interference. Experiment 2A replicated these results in a version of the conflict task without combined S-S/S-R trials. Experiment 2B increased the proportion of congruent (non-conflict) trials to promote reliance on goal-maintenance processes. Here, higher-WMC subjects resolved both S-S and S-R conflict more successfully than did lower-WMC subjects. The results were consistent with Kane and Engle’s (2003) two-factor theory of cognitive control, according to which WMC predicts executive-task performance through goal-maintenance and conflict-resolution processes. However, the present results add specificity to the account by suggesting that higher-WMC subjects better resolve cognitive conflict because they more efficiently select relevant stimulus features against irrelevant, distracting ones. PMID:26120774

  8. Carving executive control at its joints: Working memory capacity predicts stimulus-stimulus, but not stimulus-response, conflict.

    PubMed

    Meier, Matt E; Kane, Michael J

    2015-11-01

    Three experiments examined the relation between working memory capacity (WMC) and 2 different forms of cognitive conflict: stimulus-stimulus (S-S) and stimulus-response (S-R) interference. Our goal was to test whether WMC's relation to conflict-task performance is mediated by stimulus-identification processes (captured by S-S conflict), response-selection processes (captured by S-R conflict), or both. In Experiment 1, subjects completed a single task presenting both S-S and S-R conflict trials, plus trials that combined the 2 conflict types. We limited ostensible goal-maintenance contributions to performance by requiring the same goal for all trial types and by presenting frequent conflict trials that reinforced the goal. WMC predicted resolution of S-S conflict as expected: Higher WMC subjects showed reduced response time interference. Although WMC also predicted S-R interference, here, higher WMC subjects showed increased error interference. Experiment 2A replicated these results in a version of the conflict task without combined S-S/S-R trials. Experiment 2B increased the proportion of congruent (nonconflict) trials to promote reliance on goal-maintenance processes. Here, higher WMC subjects resolved both S-S and S-R conflict more successfully than did lower WMC subjects. The results were consistent with Kane and Engle's (2003) 2-factor theory of cognitive control, according to which WMC predicts executive-task performance through goal-maintenance and conflict-resolution processes. However, the present results add specificity to the account by suggesting that higher WMC subjects better resolve cognitive conflict because they more efficiently select relevant stimulus features against irrelevant, distracting ones.

  9. Remote orbital recurrence of olfactory neuroblastoma (esthesioneuroblastoma).

    PubMed

    Breazzano, Mark P; Lewis, James S; Chambless, Lola B; Rohde, Sarah L; Sobel, Rachel K

    2017-03-31

    Olfactory neuroblastoma is a rare and often locally aggressive malignancy that invades the orbit via local destruction. It is known to recur in a delayed fashion, particularly to the neck lymph nodes. This is a case of a 65-year-old gentleman who presents with recurrence in the orbit and a neck lymph node 19 years after treatment for his initial disease. This report describes the longest known interval in orbital recurrence and should alert the monitoring physician that extreme delays in recurrence can occur.

  10. Canine olfactory detection of malignant melanoma

    PubMed Central

    Campbell, Leon Frederick; Farmery, Luke; George, Susannah Mary Creighton; Farrant, Paul B J

    2013-01-01

    Our patient is a 75-year-old man who presented after his pet dog licked persistently at an asymptomatic lesion behind his right ear. Examination revealed a nodular lesion in the postauricular sulcus. Histology confirmed malignant melanoma, which was subsequently excised. Canine olfactory detection of human malignancy is a well-documented phenomenon. Advanced olfaction is hypothesised to explain canine detection of bladder, breast, colorectal, lung, ovarian, prostate and skin cancers. Further research in this area may facilitate the development of a highly accurate aid to diagnosis for many malignancies, including melanoma. PMID:24127369

  11. Cyto- and chemoarchitecture of the monotreme olfactory tubercle.

    PubMed

    Ashwell, Ken W S

    2006-01-01

    This study was undertaken to determine whether the olfactory tubercles of two monotremes (platypus and echidna) showed cyto- or chemoarchitectural differences from the tubercles of therian mammals. Nissl staining was applied in conjunction with enzyme reactivity for NADPH diaphorase and acetylcholinesterase, and immunoreactivity for calcium binding proteins (parvalbumin, calbindin and calretinin) and tyrosine hydroxylase (echidna only). Golgi impregnations of the tubercle were also available for the echidna. The olfactory tubercle is a poorly laminated structure in the echidna, despite the pronounced development of other components of the echidna olfactory system, and the dense cell layer of the olfactory tubercle was found to be discontinuous and irregular. Granule cell clusters (islands of Calleja) were present, but were small, poorly defined and did not show the intense NADPH diaphorase activity seen in marsupial and placental mammals. A putative small island of Calleja magna was seen in only one echidna out of four. In Golgi impregnations of the echidna olfactory tubercle, the most abundant neuron type was a medium-sized densely spined neuron similar to that seen in the olfactory tubercle of some therians. Large spine-poor neurons were also seen in the polymorphic layer. In the platypus, the olfactory tubercle was very small but showed more pronounced lamination than the echidna, although no granule cell clusters were seen. In both monotremes, the development of the olfactory tubercle was poor relative to other components of the olfactory system (bulb and piriform cortex). The small olfactory tubercle region in the platypus is consistent with poor olfaction in that aquatic mammal, but the tubercle in the echidna is more like that of a microsmatic mammal than other placentals occupying a similar niche (e.g., insectivores).

  12. Hypothalamus-olfactory system crosstalk: orexin a immunostaining in mice.

    PubMed

    Gascuel, Jean; Lemoine, Aleth; Rigault, Caroline; Datiche, Frédérique; Benani, Alexandre; Penicaud, Luc; Lopez-Mascaraque, Laura

    2012-01-01

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

  13. Measurement and Analysis of Olfactory Responses with the Aim of Establishing an Objective Diagnostic Method for Central Olfactory Disorders

    NASA Astrophysics Data System (ADS)

    Uno, Tominori; Wang, Li-Qun; Miwakeichi, Fumikazu; Tonoike, Mitsuo; Kaneda, Teruo

    In order to establish a new diagnostic method for central olfactory disorders and to identify objective indicators, we measured and analyzed brain activities in the parahippocampal gyrus and uncus, region of responsibility for central olfactory disorders. The relationship between olfactory stimulation and brain response at region of responsibility can be examined in terms of fitted responses (FR). FR in these regions may be individual indicators of changes in brain olfactory responses. In the present study, in order to non-invasively and objectively measure olfactory responses, an odor oddball task was conducted on four healthy volunteers using functional magnetic resonance imaging (fMRI) and a odorant stimulator with blast-method. The results showed favorable FR and activation in the parahippocampal gyrus or uncus in all subjects. In some subjects, both the parahippocampal gyrus and uncus were activated. Furthermore, activation was also confirmed in the cingulate gyrus, middle frontal gyrus, precentral gyrus, postcentral gyrus, superior temporal gyrus and insula. The hippocampus and uncus are known to be involved in the olfactory disorders associated with early-stage Alzheimer's disease and other olfactory disorders. In the future, it will be necessary to further develop the present measurement and analysis method to clarify the relationship between central olfactory disorders and brain activities and establish objective indicators that are useful for diagnosis.

  14. Monoclonal antibody immunohistochemistry of degenerative and renewal patterns in rabbit olfactory receptor neurons following unilateral olfactory bulbectomy.

    PubMed

    Onoda, N

    1988-09-01

    Degeneration and regeneration of olfactory receptor neurons were studied in adult rabbits by immunohistochemical procedures following unilateral olfactory bulbectomy. Staining patterns of the olfactory receptors of the lesioned side were compared with those of the intact side in the nasal septum at various postoperative periods (12h-6 months) following lesion. Monoclonal antibodies, produced against the rabbit olfactory bulb, were used as histochemical markers. A slight decrease in the number of olfactory receptor neurons occurred at 24 h after lesion. One monoclonal antibody 112D5 stained all receptor neurons including degenerating neurons, but the other 114G12 showed a rapid decrease in immunostaining so that 114G12-positive cells disappeared within 7 days after lesion. 114G12-positive cells reappeared at 4 weeks following lesion. By 3 months, 114G12-positive cells were arranged in a plane at the apical region of the superficial compartment of the receptor cell layer, suggesting a recapitulation of development pattern of the receptor neurons. Thereafter, the number of 114G12-positive cells increased progressively and the staining pattern of the olfactory epithelium was like that of control animals by 6 months. Monoclonal antibody 114G12 is thus the first marker that is not specific to olfactory neurons and can be used to characterize certain embryonic traits during the degeneration and regeneration of the olfactory epithelium in the adult mammal.

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

    PubMed

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

    2015-05-20

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

  16. Facilities Bonds Prove Hot Item under Stimulus

    ERIC Educational Resources Information Center

    Klein, Alyson

    2009-01-01

    Construction bonding authority--a technical, and often obscure, source of capital funding for school districts--has emerged as a hot ticket for those looking to finance school facilities work under the federal government's economic-stimulus program. School districts left out of the loop for direct funding are lining up for some of at least $24…

  17. States Hurt as Stimulus Loses Steam

    ERIC Educational Resources Information Center

    Cavanagh, Sean; Hollingsworth, Heather

    2011-01-01

    States are finally arriving at the "funding cliff"--the point where about $100 billion in federal economic-stimulus aid for education runs out. The loss seems certain to compound severe budget woes and could mean thousands of school layoffs and the elimination of popular programs and services in districts across the country. The bulk of…

  18. Electrophysiological Correlates of Stimulus Equivalence Processes

    ERIC Educational Resources Information Center

    Haimson, Barry; Wilkinson, Krista M.; Rosenquist, Celia; Ouimet, Carolyn; McIlvane, William J.

    2009-01-01

    Research reported here concerns neural processes relating to stimulus equivalence class formation. In Experiment 1, two types of word pairs were presented successively to normally capable adults. In one type, the words had related usage in English (e.g., uncle, aunt). In the other, the two words were not typically related in their usage (e.g.,…

  19. States Anxious to Get Details about Stimulus

    ERIC Educational Resources Information Center

    Hoff, David J.

    2009-01-01

    As Congress began debate last week over the size and scope of more than $120 billion in proposed emergency education aid, state leaders were anxiously awaiting the details so they could make specific plans to spend the economic-stimulus money. Governors, state legislators, and state schools chiefs have yet to learn what rules Congress will attach…

  20. The Poverty of the Mayan Stimulus

    ERIC Educational Resources Information Center

    Pye, Clifton

    2012-01-01

    Poverty of the stimulus (POS) arguments have instigated considerable debate in the recent linguistics literature. This article uses the comparative method to challenge the logic of POS arguments. Rather than question the premises of POS arguments, the article demonstrates how POS arguments for individual languages lead to a "reductio ad absurdum"…

  1. Stimulus polarity and conditioning in planaria.

    PubMed

    BARNES, C D; KATZUNG, B G

    1963-08-23

    Orientation in the monopolar pulse field used as the unconditioned stimulus was found to influence formation of a conditioned response to light in planarians. Planarians trained while oriented with the head toward the cathode reached maximal response rates rapidly, while those trained while oriented toward the anode showed no evidence of conditioned response formation.

  2. Stimulus Picture Identification in Articulation Testing

    ERIC Educational Resources Information Center

    Mullen, Patricia A.; Whitehead, Robert L.

    1977-01-01

    Compared with 20 normal speaking and 20 articulation defective Ss (7 and 8 years old) was the percent of correct initial identification of stimulus pictures on the Goldman-Fristoe Test of Articulation with the percent correct identification on the Arizona Articulation Proficiency Scale. (Author/IM)

  3. Bigrams and the Richness of the Stimulus

    ERIC Educational Resources Information Center

    Kam, Xuan-Nga Cao; Stoyneshka, Iglika; Tornyova, Lidiya; Fodor, Janet D.; Sakas, William G.

    2008-01-01

    Recent challenges to Chomsky's "poverty of the stimulus" thesis for language acquisition suggest that children's primary data may carry "indirect evidence" about linguistic constructions despite containing no instances of them. Indirect evidence is claimed to suffice for grammar acquisition, without need for innate knowledge. This article reports…

  4. Verbal Stimulus Control and the Intraverbal Relation

    ERIC Educational Resources Information Center

    Sundberg, Mark L.

    2016-01-01

    The importance of the intraverbal relation is missed in most theories of language. Skinner (1957) attributes this to traditional semantic theories of meaning that focus on the nonverbal referents of words and neglect verbal stimuli as separate sources of control for linguistic behavior. An analysis of verbal stimulus control is presented, along…

  5. Stimulus control of cocaine self-administration.

    PubMed Central

    Weiss, Stanley J; Kearns, David N; Cohn, Scott I; Schindler, Charles W; Panlilio, Leigh V

    2003-01-01

    Environmental stimuli that set the occasion wherein drugs are acquired can "trigger" drug-related behavior. Investigating the stimulus control of drug self-administration in laboratory animals should help us better understand this aspect of human drug abuse. Stimulus control of cocaine self-administration was generated here for the first time using multiple and chained schedules with short, frequently-alternating components--like those typically used to study food-maintained responding. The procedures and results are presented along with case histories to illustrate the strategies used to produce this stimulus control. All these multicomponent schedules contained variable-interval (VI) components as well as differential-reinforcement-of-other-behavior (DRO) or extinction components. Schedule parameters and unit dose were adjusted for each rat to produce stable, moderate rates in VI components, with minimal postreinforcement (infusion) pausing, and response cessation in extinction and DRO components. Whole-body drug levels on terminal baselines calculated retrospectively revealed that all rats maintained fairly stable drug levels (mean, 2.3 to 3.4 mg/kg) and molar rates of intake (approximately 6.0 mg/kg/hr). Within this range, no relation between local VI response rates and drug level was found. The stimulus control revealed in cumulative records was indistinguishable from that achieved with food under these schedules, suggesting that common mechanisms may underlie the control of cocaine- and food-maintained behavior. PMID:12696744

  6. Spatio-Temporal Characteristics of Inhibition Mapped by Optical Stimulation in Mouse Olfactory Bulb

    PubMed Central

    Lehmann, Alexander; D’Errico, Anna; Vogel, Martin; Spors, Hartwig

    2016-01-01

    Mitral and tufted cells (MTCs) of the mammalian olfactory bulb 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 five glomerular diameters. The inhibitory maps exhibited non-symmetrical yet distance-dependent characteristics. PMID:27047340

  7. Adaptation as a mechanism for gain control in cockroach ON and OFF olfactory receptor neurons.

    PubMed

    Burgstaller, Maria; Tichy, Harald

    2012-02-01

    In many sensory systems adaptation acts as a gain control mechanism that optimizes sensory performance by trading increased sensitivity to low stimulus intensity for decreased sensitivity to high stimulus intensity. Adaptation of insect antennal olfactory receptor neurons (ORNs) has been studied for strong odour concentrations, either pulsed or constant. Here, we report that during slowly oscillating changes in the concentration of the odour of lemon oil, the ON and OFF ORNs on the antenna of the cockroach Periplaneta americana adapt to the actual odour concentration and the rate at which concentration changes. When odour concentration oscillates rapidly with brief periods, adaptation improves gain for instantaneous odour concentration and reduces gain for the rate of concentration change. Conversely, when odour concentration oscillates slowly with long periods, adaptation increases gain for the rate of change at the expense of instantaneous concentration. Without this gain control the ON and OFF ORNs would, at brief oscillation periods, soon reach their saturation level and become insensitive to further concentration increments and decrements. At long oscillation periods, on the other hand, the cue would simply be that the discharge begins to change. Because of the high gain for the rate of change, the cockroach will receive creeping changes in odour concentration, even if they persist in one direction. Gain control permits a high degree of precision at small rates when it counts most, without sacrificing the range of detection and without extending the measuring scale.

  8. Color modulates olfactory learning in honeybees by an occasion-setting mechanism.

    PubMed

    Mota, Theo; Giurfa, Martin; Sandoz, Jean-Christophe

    2011-01-01

    A sophisticated form of nonelemental learning is provided by occasion setting. In this paradigm, animals learn to disambiguate an uncertain conditioned stimulus using alternative stimuli that do not enter into direct association with the unconditioned stimulus. For instance, animals may learn to discriminate odor rewarded from odor nonrewarded trials if these two situations are indicated by different colors that do not themselves become associated with the reward. Despite a growing interest in nonelemental learning in insects, no study has so far attempted to study occasion setting in restrained honeybees, although this would allow direct access to the neural basis of nonelemental learning. Here we asked whether colors can modulate olfactory conditioning of the proboscis extension reflex (PER) via an occasion-setting mechanism. We show that intact, harnessed bees are not capable of learning a direct association between color and sucrose. Despite this incapacity, bees solved an occasion-setting discrimination in which colors set the occasion for appropriate responding to an odor that was rewarded or nonrewarded depending on the color. We therefore provide the first controlled demonstration of bimodal (color-odor) occasion setting in harnessed honeybees, which opens the door for studying the neural basis of such bimodal, nonelemental discriminations in insects.

  9. Volatile exposure within the honeybee hive and its effect on olfactory discrimination.

    PubMed

    Fernández, Vanesa M; Arenas, Andrés; Farina, Walter M

    2009-08-01

    Honeybees of different ages and reproductive castes cohabit in the hive where they are exposed to many odors that might affect associative learning. Our aim was to analyze the role of odors pre-exposed as volatiles on appetitive learning in honeybees of different ages and search for their long-term effect both under natural and laboratory conditions. By evaluating memory acquisition and retention through a differential proboscis extension response conditioning, we found that hive-exposed odors offered as a reinforced conditioned stimulus during training promoted a learning-reduced effect [latent inhibition (LI)]. On the other hand, no effect was found when the non-reinforced conditioned stimulus was pre-exposed. The LI effect varied with the odor identity. However, only slight differences were found with the age of the bees. Exposure-conditioning intervals longer than 24 h did not show an LI effect unless the odor concentration was increased or exposure was prolonged. Our results show that pre-exposed volatiles could either reduce learning performance, if this odor is later associated with food, or be irrelevant in the case that alternative scented resources circulate within the colony. The differential effects found according to the olfactory exposure characteristics could strongly influence the propagation of chemosensory information within the hive.

  10. Effects of allocation of attention on habituation to olfactory and visual food stimuli in children.

    PubMed

    Epstein, Leonard H; Saad, Frances G; Giacomelli, April M; Roemmich, James N

    2005-02-15

    Responding to food cues may be disrupted by allocating attention to other tasks. We report two experiments examining the effects of allocation of attention on salivary habituation to olfactory plus visual food cues in 8-12-year-old children. In Experiment 1, 42 children were presented with a series of 8 hamburger food stimulus presentations. During each intertrial interval, participants completed a controlled (hard), or automatic (easy) visual memory task, or no task (control). In Experiment 2, 22 children were presented with 10 presentations of a pizza food stimulus and either listened to an audiobook or no audiobook control. Results of Experiment 1 showed group differences in rate of change in salivation (p=0.014). Children in the controlled task did not habituate to repeated food cues, while children in the automatic (p<0.005) or no task (p<0.001) groups decreased responding over time. In Experiment 2, groups differed in the rate of change in salivation (p=0.004). Children in the no audiobook group habituated (p<0.001), while children in the audiobook group did not habituate. Changes in the rate of habituation when attending to non-food stimuli while eating may be a mechanism for increasing energy intake.

  11. Gated currents in isolated olfactory receptor neurons of the larval tiger salamander.

    PubMed

    Firestein, S; Werblin, F S

    1987-09-01

    The electrical properties of enzymatically isolated olfactory receptor cells were studied with whole-cell patch clamp. Voltage-dependent currents could be separated into three ionic components: a transient inward sodium current, a sustained inward calcium current, and an outward potassium current. Three components of the outward current could be identified by their gating and kinetics: a calcium-dependent potassium current [IK(Ca)], a voltage-dependent potassium current [IK(V)], and a transient potassium current (Ia). Typical resting potentials were near -54 mV, and typical input resistance was 3-6 G omega. Thus, only 3 pA of injected current was required to depolarize the cell to spike threshold near -45 mV. The response to a current step consisted of either a single spike regardless of stimulus strength, or a train of less than 8 spikes, decrementing in amplitude and frequency over approximately equal to 250 msec. Thus, the receptor response cannot be finely graded with stimulus intensity.

  12. Asymmetrical stimulus generalization following differential fear conditioning.

    PubMed

    Bang, Sun Jung; Allen, Timothy A; Jones, Lauren K; Boguszewski, Pawel; Brown, Thomas H

    2008-07-01

    Rodent ultrasonic vocalizations (USVs) are ethologically critical social signals. Rats emit 22kHz USVs and 50kHz USVs, respectively, in conjunction with negative and positive affective states. Little is known about what controls emotional reactivity to these social signals. Using male Sprague-Dawley rats, we examined unconditional and conditional freezing behavior in response to the following auditory stimuli: three 22kHz USVs, a discontinuous tone whose frequency and on-off pattern matched one of the USVs, a continuous tone with the same or lower frequencies, a 4kHz discontinuous tone with an on-off pattern matched to one of the USVs, and a 50kHz USV. There were no differences among these stimuli in terms of the unconditional elicitation of freezing behavior. Thus, the stimuli were equally neutral before conditioning. During differential fear conditioning, one of these stimuli (the CS(+)) always co-terminated with a footshock unconditional stimulus (US) and another stimulus (the CS(-)) was explicitly unpaired with the US. There were no significant differences among these cues in CS(+)-elicited freezing behavior. Thus, the stimuli were equally salient or effective as cues in supporting fear conditioning. When the CS(+) was a 22kHz USV or a similar stimulus, rats discriminated based on the principal frequency and/or the temporal pattern of the stimulus. However, when these same stimuli served as the CS(-), discrimination failed due to generalization from the CS(+). Thus, the stimuli differed markedly in the specificity of conditioning. This strikingly asymmetrical stimulus generalization is a novel bias in discrimination.

  13. Ecological adaptation determines functional mammalian olfactory subgenomes

    PubMed Central

    Hayden, Sara; Bekaert, Michaël; Crider, Tess A.; Mariani, Stefano; Murphy, William J.; Teeling, Emma C.

    2010-01-01

    The ability to smell is governed by the largest gene family in mammalian genomes, the olfactory receptor (OR) genes. Although these genes are well annotated in the finished human and mouse genomes, we still do not understand which receptors bind specific odorants or how they fully function. Previous comparative studies have been taxonomically limited and mostly focused on the percentage of OR pseudogenes within species. No study has investigated the adaptive changes of functional OR gene families across phylogenetically and ecologically diverse mammals. To determine the extent to which OR gene repertoires have been influenced by habitat, sensory specialization, and other ecological traits, to better understand the functional importance of specific OR gene families and thus the odorants they bind, we compared the functional OR gene repertoires from 50 mammalian genomes. We amplified more than 2000 OR genes in aquatic, semi-aquatic, and flying mammals and coupled these data with 48,000 OR genes from mostly terrestrial mammals, extracted from genomic projects. Phylogenomic, Bayesian assignment, and principle component analyses partitioned species by ecotype (aquatic, semi-aquatic, terrestrial, flying) rather than phylogenetic relatedness, and identified OR families important for each habitat. Functional OR gene repertoires were reduced independently in the multiple origins of aquatic mammals and were significantly divergent in bats. We reject recent neutralist views of olfactory subgenome evolution and correlate specific OR gene families with physiological requirements, a preliminary step toward unraveling the relationship between specific odors and respective OR gene families. PMID:19952139

  14. Unitary response of mouse olfactory receptor neurons

    PubMed Central

    Ben-Chaim, Yair; Cheng, Melody M.; Yau, King-Wai

    2011-01-01

    The sense of smell begins with odorant molecules binding to membrane receptors on the cilia of olfactory receptor neurons (ORNs), thereby activating a G protein, Golf, and the downstream effector enzyme, an adenylyl cyclase (ACIII). Recently, we have found in amphibian ORNs that an odorant-binding event has a low probability of activating sensory transduction at all; even when successful, the resulting unitary response apparently involves a single active Gαolf–ACIII molecular complex. This low amplification is in contrast to rod phototransduction in vision, the best-quantified G-protein signaling pathway, where each photoisomerized rhodopsin molecule is well known to produce substantial amplification by activating many G-protein, and hence effector-enzyme, molecules. We have now carried out similar experiments on mouse ORNs, which offer, additionally, the advantage of genetics. Indeed, we found the same low probability of transduction, based on the unitary olfactory response having a fairly constant amplitude and similar kinetics across different odorants and randomly encountered ORNs. Also, consistent with our picture, the unitary response of Gαolf+/− ORNs was similar to WT in amplitude, although their Gαolf-protein expression was only half of normal. Finally, from the action potential firing, we estimated that ≤19 odorant-binding events successfully triggering transduction in a WT mouse ORN will lead to signaling to the brain. PMID:21187398

  15. Machine-learned pattern identification in olfactory subtest results

    PubMed Central

    Lötsch, Jörn; Hummel, Thomas; Ultsch, Alfred

    2016-01-01

    The human sense of smell is often analyzed as being composed of three main components comprising olfactory threshold, odor discrimination and the ability to identify odors. A relevant distinction of the three components and their differential changes in distinct disorders remains a research focus. The present data-driven analysis aimed at establishing a cluster structure in the pattern of olfactory subtest results. Therefore, unsupervised machine-learning was applied onto olfactory subtest results acquired in 10,714 subjects with nine different olfactory pathologies. Using the U-matrix, Emergent Self-organizing feature maps (ESOM) identified three different clusters characterized by (i) low threshold and good discrimination and identification, (ii) very high threshold associated with absent to poor discrimination and identification ability, or (iii) medium threshold, i.e., in the mid-range of possible thresholds, associated with reduced discrimination and identification ability. Specific etiologies of olfactory (dys)function were unequally represented in the clusters (p < 2.2 · 10−16). Patients with congenital anosmia were overrepresented in the second cluster while subjects with postinfectious olfactory dysfunction belonged frequently to the third cluster. However, the clusters provided no clear separation between etiologies. Hence, the present verification of a distinct cluster structure encourages continued scientific efforts at olfactory test pattern recognition. PMID:27762302

  16. Olfactory function in psychotic disorders: Insights from neuroimaging studies

    PubMed Central

    Good, Kimberley P; Sullivan, Randii Lynn

    2015-01-01

    Olfactory deficits on measures of identification, familiarity, and memory are consistently noted in patients with psychotic disorders relative to age-matched controls. Olfactory intensity ratings, however, appear to remain intact while the data on hedonics and detection threshold are inconsistent. Despite the behavioral abnormalities noted, no specific regional brain hypoactivity has been identified in psychosis patients, for any of the olfactory domains. However, an intriguing finding emerged from this review in that the amygdala and pirifom cortices were not noted to be abnormal in hedonic processing (nor was the amygdala identified abnormal in any study) in psychotic disorders. This finding is in contrast to the literature in healthy individuals, in that this brain region is strongly implicated in olfactory processing (particularly for unpleasant odorants). Secondary olfactory cortex (orbitofrontal cortices, thalamus, and insula) was abnormally activated in the studies examined, particularly for hedonic processing. Further research, using consistent methodology, is required for better understanding the neurobiology of olfactory deficits. The authors suggest taking age and sex differences into consideration and further contrasting olfactory subgroups (impaired vs intact) to better our understanding of the heterogeneity of psychotic disorders. PMID:26110122

  17. A lifetime of neurogenesis in the olfactory system

    PubMed Central

    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

  18. Delayed olfactory nerve regeneration in ApoE-deficient mice.

    PubMed

    Nathan, Britto P; Nisar, Rafia; Short, Jody; Randall, Shari; Grissom, Elin; Griffin, Gwen; Switzer, Paul V; Struble, Robert G

    2005-04-11

    Apolipoprotein E (apoE), a lipid transporting protein, is extensively expressed in the primary olfactory pathway, but its function is unknown. We previously reported increased apoE levels in the olfactory bulb (OB) following olfactory epithelium (OE) lesion in mice, and hypothesized that apoE may play a vital role in olfactory nerve (ON) regeneration. To directly test this hypothesis, we examined the rate of ON regeneration following OE lesion in apoE deficient/knockout (KO) and wild-type (WT) mice. OE was lesioned in 2- to 3-month-old mice by intranasal irrigation with Triton X-100 (TX). OB were collected at 0, 3, 7, 21, 42, and 56 days post-lesion. OB recovery was measured by both immunoblotting and immunohistochemical analysis of growth cone associated protein (GAP) 43 and olfactory marker protein (OMP). The results revealed that (1) OMP recovery in the OB was significantly slower in apoE KO compared to WT mice; (2) recovery of glomerular area was similarly slower; and (3) GAP43 increases and return to prelesion levels in the OB were slower in KO mice. Together, these results show that olfactory nerve regeneration is significantly slower in KO mice as compared to WT mice, suggesting apoE facilitates olfactory nerve regeneration.

  19. Understanding complex behavior: The transformation of stimulus functions

    PubMed Central

    Dymond, Simon; Rehfeldt, Ruth Anne

    2000-01-01

    The transformation of stimulus functions is said to occur when the functions of one stimulus alter or transform the functions of another stimulus in accordance with the derived relation between the two, without additional training. This effect has been demonstrated with a number of derived stimulus relations, behavioral functions, experimental preparations, and subject populations. The present paper reviews much of the existing research on the transformation of stimulus functions and outlines a number of important methodological and conceptual issues that warrant further attention. We conclude by advocating the adoption of the generic terminology of relational frame theory to describe both the derived transformation of stimulus functions and relational responding more generally. PMID:22478349

  20. Respiratory and olfactory turbinal size in canid and arctoid carnivorans

    PubMed Central

    Green, Patrick A; Valkenburgh, Blaire; Pang, Benison; Bird, Deborah; Rowe, Timothy; Curtis, Abigail

    2012-01-01

    Within the nasal cavity of mammals is a complex scaffold of paper-thin bones that function in respiration and olfaction. Known as turbinals, the bones greatly enlarge the surface area available for conditioning inspired air, reducing water loss, and improving olfaction. Given their functional significance, the relative development of turbinal bones might be expected to differ among species with distinct olfactory, thermoregulatory and/or water conservation requirements. Here we explore the surface area of olfactory and respiratory turbinals relative to latitude and diet in terrestrial Caniformia, a group that includes the canid and arctoid carnivorans (mustelids, ursids, procyonids, mephitids, ailurids). Using high-resolution computed tomography x-ray scans, we estimated respiratory and olfactory turbinal surface area and nasal chamber volume from three-dimensional virtual models of skulls. Across the Caniformia, respiratory surface area scaled isometrically with estimates of body size and there was no significant association with climate, as estimated by latitude. Nevertheless, one-on-one comparisons of sister taxa suggest that arctic species may have expanded respiratory turbinals. Olfactory surface area scaled isometrically among arctoids, but showed positive allometry in canids, reflecting the fact that larger canids, all of which are carnivorous, had relatively greater olfactory surface areas. In addition, among the arctoids, large carnivorous species such as the polar bear (Ursus maritimus) and wolverine (Gulo gulo) also displayed enlarged olfactory turbinals. More omnivorous caniform species that feed on substantial quantities of non-vertebrate foods had less expansive olfactory turbinals. Because large carnivorous species hunt widely dispersed prey, an expanded olfactory turbinal surface area may improve a carnivore's ability to detect prey over great distances using olfactory cues. PMID:23035637

  1. Cellular basis for the olfactory response to nicotine.

    PubMed

    Bryant, Bruce; Xu, Jiang; Audige, Valery; Lischka, Fritz W; Rawson, Nancy E

    2010-03-17

    Smokers regulate their smoking behavior on the basis of sensory stimuli independently of the pharmacological effects of nicotine (Rose J. E., et al. (1993) Pharmacol., Biochem. Behav.44 (4), 891-900). A better understanding of sensory mechanisms underlying smoking behavior may help to develop more effective smoking alternatives. Olfactory stimulation by nicotine makes up a considerable part of the flavor of tobacco smoke, yet our understanding of the cellular mechanisms responsible for olfactory detection of nicotine remains incomplete. We used biophysical methods to characterize the nicotine sensitivity and response mechanisms of neurons from olfactory epithelium. In view of substantial differences in the olfactory receptor repertoire between rodent and human (Mombaerts P. (1999) Annu. Rev. Neurosci.22, 487-509), we studied biopsied human olfactory sensory neurons (OSNs), cultured human olfactory cells (Gomez G., et al. (2000) J. Neurosci. Res.62 (5), 737-749), and rat olfactory neurons. Rat and human OSNs responded to S(-)-nicotine with a concentration dependent influx of calcium and activation of adenylate cyclase. Some rat OSNs displayed some stereoselectivity, with neurons responding to either enantiomer alone or to both. Freshly biopsied and primary cultured human olfactory neurons were less stereoselective. Nicotinic cholinergic antagonists had no effect on the responses of rat or human OSNs to nicotine. Patch clamp recording of rat OSNs revealed a nicotine-activated, calcium-sensitive nonspecific cation channel. These results indicate that nicotine activates a canonical olfactory receptor pathway rather than nicotinic cholinergic receptors on OSNs. Further, because the nicotine-sensitive mechanisms of rodents appear generally similar to those of humans, this animal model is an appropriate one for studies of nicotine sensation.

  2. Neural correlates of olfactory learning paradigms in an identified neuron in the honeybee brain.

    PubMed

    Mauelshagen, J

    1993-02-01

    1. Sensitization and classical odor conditioning of the proboscis extension reflex were functionally analyzed by repeated intracellular recordings from a single identified neuron (PE1-neuron) in the central bee brain. This neuron belongs to the class of "extrinsic cells" arising from the pedunculus of the mushroom bodies and has extensive arborizations in the median and lateral protocerebrum. The recordings were performed on isolated bee heads. 2. Two different series of physiological experiments were carried out with the use of a similar temporal succession of stimuli as in previous behavioral experiments. In the first series, one group of animals was used for a single conditioning trial [conditioned stimulus (CS), carnation; unconditioned stimulus (US), sucrose solution to the antennae and proboscis), a second group was used for sensitization (sensitizing stimulus, sucrose solution to the antennae and/or proboscis), and the third group served as control (no sucrose stimulation). In the second series, a differential conditioning paradigm (paired odor CS+, carnation; unpaired odor CS-, orange blossom) was applied to test the associative nature of the conditioning effect. 3. The PE1-neuron showed a characteristic burstlike odor response before the training procedures. The treatments resulted in different spike-frequency modulations of this response, which were specific for the nonassociative and associative stimulus paradigms applied. During differential conditioning, there are dynamic up and down modulations of spike frequencies and of the DC potentials underlying the responses to the CS+. Overall, only transient changes in the minute range were observed. 4. The results of the sensitization procedures suggest two qualitatively different US pathways. The comparison between sensitization and one-trial conditioning shows differential effects of nonassociative and associative stimulus paradigms on the response behavior of the PE1-neuron. The results of the differential

  3. Spatial pattern of receptor expression in the olfactory epithelium.

    PubMed Central

    Nef, P; Hermans-Borgmeyer, I; Artières-Pin, H; Beasley, L; Dionne, V E; Heinemann, S F

    1992-01-01

    A PCR-based strategy for amplifying putative receptors involved in murine olfaction was employed to isolate a member (OR3) of the seven-transmembrane-domain receptor superfamily. During development, the first cells that express OR3 appear adjacent to the wall of the telencephalic vesicle at embryonic day 10. The OR3 receptor is uniquely expressed in a subset of olfactory cells that have a characteristic bilateral symmetry in the adult olfactory epithelium. This receptor and its specific pattern of expression may serve a functional role in odor coding or, alternatively, may play a role in the development of the olfactory system. Images PMID:1384038

  4. Dynamic cortical lateralization during olfactory discrimination learning

    PubMed Central

    Cohen, Yaniv; Putrino, David; Wilson, Donald A

    2015-01-01

    Key points Odour discrimination and memory involve changes in the primary olfactory (piriform) cortex. The results obtained in the present study suggest that there is an asymmetry in piriform cortical change, with learning-related changes in cortical oscillations emerging with different time courses over the course of multiday training in the left and right piriform cortices in rats. There is an initial decrease in coherence between the left and right piriform cortices during the early stages of the odour discrimination task, which recovers as the animals approach criterion performance. This decreased coherence is expressed when the animals are performing the task relative to when they are in their home cage. The results suggest a transient cortical asymmetry during learning and raise new questions about the functions and mechanisms of cerebral lateralization. Abstract Bilateral cortical circuits are not necessarily symmetrical. Asymmetry, or cerebral lateralization, allows functional specialization of bilateral brain regions and has been described in humans for such diverse functions as perception, memory and emotion. There is also evidence for asymmetry in the human olfactory system, although evidence in non-human animal models is lacking. In the present study, we took advantage of the known changes in olfactory cortical local field potentials that occur over the course of odour discrimination training to test for functional asymmetry in piriform cortical activity during learning. Both right and left piriform cortex local field potential activities were recorded. The results obtained demonstrate a robust interhemispheric asymmetry in anterior piriform cortex activity that emerges during specific stages of odour discrimination learning, with a transient bias toward the left hemisphere. This asymmetry is not apparent during error trials. Furthermore, functional connectivity (coherence) between the bilateral anterior piriform cortices is learning- and context

  5. Electrophysiological Correlates of Stimulus Equivalence Processes

    PubMed Central

    Haimson, Barry; Wilkinson, Krista M; Rosenquist, Celia; Ouimet, Carolyn; McIlvane, William J

    2009-01-01

    Research reported here concerns neural processes relating to stimulus equivalence class formation. In Experiment 1, two types of word pairs were presented successively to normally capable adults. In one type, the words had related usage in English (e.g., uncle, aunt). In the other, the two words were not typically related in their usage (e.g., wrist, corn). For pairs of both types, event-related cortical potentials were recorded during and immediately after the presentation of the second word. The obtained waveforms differentiated these two types of pairs. For the unrelated pairs, the waveforms were significantly more negative about 400 ms after the second word was presented, thus replicating the “N400” phenomenon of the cognitive neuroscience literature. In addition, there was a strong positive-tending wave form difference post-stimulus presentation (peaked at about 500 ms) that also differentiated the unrelated from related stimulus pairs. In Experiment 2, the procedures were extended to study arbitrary stimulus–stimulus relations established via matching-to-sample training. Participants were experimentally naïve adults. Sample stimuli (Set A) were trigrams, and comparison stimuli (Sets B, C, D, E, and F) were nonrepresentative forms. Behavioral tests evaluated potentially emergent equivalence relations (i.e., BD, DF, CE, etc.). All participants exhibited classes consistent with the arbitrary matching training. They were also exposed also to an event-related potential procedure like that used in Experiment 1. Some received the ERP procedure before equivalence tests and some after. Only those participants who received ERP procedures after equivalence tests exhibited robust N400 differentiation initially. The positivity observed in Experiment 1 was absent for all participants. These results support speculations that equivalence tests may provide contextual support for the formation of equivalence classes including those that emerge gradually during testing

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

    PubMed Central

    Brus, Maïna; Meurisse, Maryse; Keller, Matthieu; Lévy, Frédéric

    2014-01-01

    New neurons are continuously added in the dentate gyrus (DG) and the olfactory bulb of mammalian brain. While numerous environmental factors controlling survival of newborn neurons have been extensively studied, regulation by social interactions is less documented. We addressed this question by investigating the influence of parturition and interactions with the young on neurogenesis in sheep mothers. Using Bromodeoxyuridine, a marker of cell division, in combination with markers of neuronal maturation, the percentage of neuroblasts and new mature neurons in the olfactory bulb and the DG was compared between groups of parturient ewes which could interact or not with their lamb, and virgins. In addition, a morphological analysis was performed by measuring the dendritic arbor of neuroblasts in both structures. We showed that the postpartum period was associated with a decrease in olfactory and hippocampal adult neurogenesis. In the olfactory bulb, the suppressive effect on neuroblasts was dependent on interactions with the young whereas in the DG the decrease in new mature neurons was associated with parturition. In addition, dendritic length and number of nodes of neuroblasts were significantly enhanced by interactions with the lamb in the olfactory bulb but not in the DG. Because interactions with the young involved learning of the olfactory signature of the lamb, we hypothesize that this learning is associated with a down-regulation in olfactory neurogenesis and an enhancement of olfactory neuroblast maturation. Our assumption is that fewer new neurons decrease cell competition in the olfactory bulb and enhance maturation of those new neurons selected to participate in the learning of the young odor. PMID:24600367

  7. Impact of stimulus uncanniness on speeded response

    PubMed Central

    Takahashi, Kohske; Fukuda, Haruaki; Samejima, Kazuyuki; Watanabe, Katsumi; Ueda, Kazuhiro

    2015-01-01

    In the uncanny valley phenomenon, the causes of the feeling of uncanniness as well as the impact of the uncanniness on behavioral performances still remain open. The present study investigated the behavioral effects of stimulus uncanniness, particularly with respect to speeded response. Pictures of fish were used as visual stimuli. Participants engaged in direction discrimination, spatial cueing, and dot-probe tasks. The results showed that pictures rated as strongly uncanny delayed speeded response in the discrimination of the direction of the fish. In the cueing experiment, where a fish served as a task-irrelevant and unpredictable cue for a peripheral target, we again observed that the detection of a target was slowed when the cue was an uncanny fish. Conversely, the dot-probe task suggested that uncanny fish, unlike threatening stimulus, did not capture visual spatial attention. These results suggested that stimulus uncanniness resulted in the delayed response, and importantly this modulation was not mediated by the feelings of threat. PMID:26052297

  8. Stimulus control in a two-choice discrimination procedure

    NASA Technical Reports Server (NTRS)

    Galloway, W. D.

    1973-01-01

    Experimental investigation upon pigeons of the relation between performance during discriminative training and subsequently obtained stimulus control test results. The results obtained support the proposition that bias generated by training dependencies is a major determiner of stimulus control.

  9. Top-down modulation of olfactory-guided behaviours by the anterior olfactory nucleus pars medialis and ventral hippocampus

    PubMed Central

    Aqrabawi, Afif J.; Browne, Caleb J.; Dargaei, Zahra; Garand, Danielle; Khademullah, C. Sahara; Woodin, Melanie A.; Kim, Jun Chul

    2016-01-01

    Olfactory processing is thought to be actively modulated by the top-down input from cortical regions, but the behavioural function of these signals remains unclear. Here we find that cortical feedback from the anterior olfactory nucleus pars medialis (mAON) bidirectionally modulates olfactory sensitivity and olfaction-dependent behaviours. To identify a limbic input that tunes this mAON switch, we further demonstrate that optogenetic stimulation of ventral hippocampal inputs to the mAON is sufficient to alter olfaction-dependent behaviours. PMID:28004701

  10. The Evolution of Mammalian Olfactory Receptor Genes

    PubMed Central

    Issel-Tarver, L.; Rine, J.

    1997-01-01

    We performed a comparative study of four subfamilies of olfactory receptor genes first identified in the dog to assess changes in the gene family during mammalian evolution, and to begin linking the dog genetic map to that of humans. The human subfamilies were localized to chromosomes 7, 11, and 19. The two subfamilies that were tightly linked in the dog genome were also tightly linked in the human genome. The four subfamilies were compared in human (primate), horse (perissodactyl), and a variety of artiodactyls and carnivores. Some changes in gene number were detected, but overall subfamily size appeared to have been established before the divergence of these mammals 60-100 million years ago. PMID:9017400

  11. Olfactory groove meningiomas: approaches and complications.

    PubMed

    Aguiar, Paulo Henrique Pires de; Tahara, Adriana; Almeida, Antonio Nogueira; Simm, Renata; Silva, Arnaldo Neves da; Maldaun, Marcos Vinicius Calfatt; Panagopoulos, Alexandros Theodoros; Zicarelli, Carlos Alexandre; Silva, Pedro Gabriel

    2009-09-01

    Olfactory groove meningiomas (OGM) account for 4.5% of all intracranial meningiomas. We report 21 patients with OGMs. Tumors were operated on using three surgical approaches: bifrontal (7 patients), fronto-pterional (11 patients) and fronto-orbital (3 patients). Total tumor removal (Simpson Grade 1) was achieved in 13 patients and Simpson II in 8 patients. Perioperative mortality was 4.76%. The average size of the OGM was 4.3+/-1.1cm. The overall recurrence rate was 19%. We preferred to use the pterional approach, which provides quick access to the tumor with less brain exposure. It also allows complete drainage of cisternal cerebrospinal fluid, providing a good level of brain relaxation during surgery. However, for long, thin tumors, hemostasis can be difficult using this approach.

  12. A further analysis of olfactory cortex development

    PubMed Central

    Pedraza, María; De Carlos, Juan A.

    2012-01-01

    The olfactory cortex (OC) is a complex yet evolutionarily well-conserved brain region, made up of heterogeneous cell populations that originate in different areas of the developing telencephalon. Indeed, these cells are among the first cortical neurons to differentiate. To date, the development of the OC has been analyzed using birthdating techniques along with molecular markers and in vivo or in vitro tracking methods. In the present study, we sought to determine the origin and adult fate of these cell populations using ultrasound-guided in utero injections and electroporation of different genomic plasmids into the lateral walls of the ventricles. Our results provide direct evidence that in the mouse OC, cell fate is determined by the moment and place of origin of each specific cell populations. Moreover, by combining these approaches with the analysis of specific cell markers, we show that the presence of pallial and subpallial markers in these areas is independent of cell origin. PMID:22969708

  13. Chemoarchitecture of the monotreme olfactory bulb.

    PubMed

    Ashwell, Ken W S

    2006-01-01

    The cyto- and chemoarchitecture of the olfactory bulb of two monotremes (shortbeaked echidna and platypus) was studied to determine if there are any chemoarchitectural differences from therian mammals. Nissl staining in conjunction with enzyme reactivity for NADPH diaphorase, and immunoreactivity for calcium binding proteins (parvalbumin, calbindin and calretinin), neuropeptide Y, tyrosine hydroxylase and non-phosphorylated neurofilament protein (SMI-32 antibody) were applied to the echidna. Material from platypus bulb was Nissl stained, immunoreacted for calretinin, or stained for NADPH diaphorase. In contrast to eutherians, no immunoreactivity for either the SMI-32 antibody or calretinin was found in the mitral or dispersed tufted cells of the monotremes and very few parvalbumin or calbindin immunoreactive neurons were found in the bulb of the echidna. On the other hand, immunoreactivity for tyrosine hydroxylase in the echidna was similar in distribution to that seen in therians, and periglomerular and granule cells showed similar patterns of calretinin immunoreactivity to eutherians. Multipolar neuropeptide Y immunoreactive neurons were confined to the deep granule cell layer and underlying white matter of the echidna bulb and NADPH diaphorase reactivity was found in occasional granule cells, fusiform and multipolar cells of the inner plexiform and granule cell layers, as well as underlying white matter. Unlike eutherians, no NPY immunoreactive or NADPH diaphorase reactive neurons were seen in the glomerular layer. The bulb of the echidna was comparable in volume to prosimians of similar body weight, and its constituent layers were highly folded. In conclusion, the monotreme olfactory bulb does not show any significant chemoarchitectural dissimilarities from eutheria, despite differences in mitral/tufted cell distribution.

  14. Proton-Beam Therapy for Olfactory Neuroblastoma

    SciTech Connect

    Nishimura, Hideki . E-mail: westvill@med.kobe-u.ac.jp; Ogino, Takashi; Kawashima, Mitsuhiko; Nihei, Keiji; Arahira, Satoko; Onozawa, Masakatsu; Katsuta, Shoichi; Nishio, Teiji

    2007-07-01

    Purpose: To analyze the feasibility and efficacy of proton-beam therapy (PBT) for olfactory neuroblastoma (ONB) as a definitive treatment, by reviewing our preliminary experience. Olfactory neuroblastoma is a rare disease, and a standard treatment strategy has not been established. Radiation therapy for ONB is challenging because of the proximity of ONBs to critical organs. Proton-beam therapy can provide better dose distribution compared with X-ray irradiation because of its physical characteristics, and is deemed to be a feasible treatment modality. Methods and Materials: A retrospective review was performed on 14 patients who underwent PBT for ONB as definitive treatment at the National Cancer Center Hospital East (Kashiwa, Chiba, Japan) from November 1999 to February 2005. A total dose of PBT was 65 cobalt Gray equivalents (Gy{sub E}), with 2.5-Gy{sub E} once-daily fractionations. Results: The median follow-up period for surviving patients was 40 months. One patient died from disseminated disease. There were two persistent diseases, one of which was successfully salvaged with surgery. The 5-year overall survival rate was 93%, the 5-year local progression-free survival rate was 84%, and the 5-year relapse-free survival rate was 71%. Liquorrhea was observed in one patient with Kadish's stage C disease (widely destroying the skull base). Most patients experienced Grade 1 to 2 dermatitis in the acute phase. No other adverse events of Grade 3 or greater were observed according to the RTOG/EORTC acute and late morbidity scoring system. Conclusions: Our preliminary results of PBT for ONB achieved excellent local control and survival outcomes without serious adverse effects. Proton-beam therapy is considered a safe and effective modality that warrants further study.

  15. Inhibition by Somatostatin Interneurons in Olfactory Cortex

    PubMed Central

    Large, Adam M.; Kunz, Nicholas A.; Mielo, Samantha L.; Oswald, Anne-Marie M.

    2016-01-01

    Inhibitory circuitry plays an integral role in cortical network activity. The development of transgenic mouse lines targeting unique interneuron classes has significantly advanced our understanding of the functional roles of specific inhibitory circuits in neocortical sensory processing. In contrast, considerably less is known about the circuitry and function of interneuron classes in piriform cortex, a paleocortex responsible for olfactory processing. In this study, we sought to utilize transgenic technology to investigate inhibition mediated by somatostatin (SST) interneurons onto pyramidal cells (PCs), parvalbumin (PV) interneurons, and other interneuron classes. As a first step, we characterized the anatomical distributions and intrinsic properties of SST and PV interneurons in four transgenic lines (SST-cre, GIN, PV-cre, and G42) that are commonly interbred to investigate inhibitory connectivity. Surprisingly, the distributions SST and PV cell subtypes targeted in the GIN and G42 lines were sparse in piriform cortex compared to neocortex. Moreover, two-thirds of interneurons recorded in the SST-cre line had electrophysiological properties similar to fast spiking (FS) interneurons rather than regular (RS) or low threshold spiking (LTS) phenotypes. Nonetheless, like neocortex, we find that SST-cells broadly inhibit a number of unidentified interneuron classes including putatively identified PV cells and surprisingly, other SST cells. We also confirm that SST-cells inhibit pyramidal cell dendrites and thus, influence dendritic integration of afferent and recurrent inputs to the piriform cortex. Altogether, our findings suggest that SST interneurons play an important role in regulating both excitation and the global inhibitory network during olfactory processing. PMID:27582691

  16. The effect of high altitude on olfactory functions.

    PubMed

    Altundağ, Aytuğ; Salihoglu, Murat; Çayönü, Melih; Cingi, Cemal; Tekeli, Hakan; Hummel, Thomas

    2014-03-01

    It is known that high-altitude trips cause nasal congestion, impaired nasal mucociliary transport rate, and increased nasal resistance, due to decreased partial oxygen pressure and dry air. It is also known that olfactory perception is affected by barometric pressure and humidity. The aim of the present study was to investigate whether olfactory function changes in relation to high altitude in a natural setting. The present study included 41 volunteers with no history of chronic rhinosinusitis or nasal polyposis. The study group consisted of 31 men (76 %) and 10 women (24 %); the mean age of the study population was 38 ± 10 years. Olfactory testing was conducted using "Sniffin' Sticks" at a high altitude (2,200 ms) and at sea level. Odor test scores for threshold and identification were significantly better at sea level than at high altitude (p < 0.001). The major finding of this investigation was that olfactory functions are decreased at high altitudes.

  17. Organization of olfactory centres in the malaria mosquito Anopheles gambiae

    PubMed Central

    Riabinina, Olena; Task, Darya; Marr, Elizabeth; Lin, Chun-Chieh; Alford, Robert; O'Brochta, David A.; Potter, Christopher J.

    2016-01-01

    Mosquitoes are vectors for multiple infectious human diseases and use a variety of sensory cues (olfactory, temperature, humidity and visual) to locate a human host. A comprehensive understanding of the circuitry underlying sensory signalling in the mosquito brain is lacking. Here we used the Q-system of binary gene expression to develop transgenic lines of Anopheles gambiae in which olfactory receptor neurons expressing the odorant receptor co-receptor (Orco) gene are labelled with GFP. These neurons project from the antennae and maxillary palps to the antennal lobe (AL) and from the labella on the proboscis to the suboesophageal zone (SEZ), suggesting integration of olfactory and gustatory signals occurs in this brain region. We present detailed anatomical maps of olfactory innervations in the AL and the SEZ, identifying glomeruli that may respond to human body odours or carbon dioxide. Our results pave the way for anatomical and functional neurogenetic studies of sensory processing in mosquitoes. PMID:27694947

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

    ERIC Educational Resources Information Center

    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. Measuring Joint Stimulus Control by Complex Graph/Description Correspondences

    ERIC Educational Resources Information Center

    Fields, Lanny; Spear, Jack

    2012-01-01

    Joint stimulus control occurs when responding is determined by the correspondence of elements of a complex sample and a complex comparison stimulus. In academic settings, joint stimulus control of behavior would be evidenced by the selection of an accurate description of a complex graph in which each element of a graph corresponded to particular…

  20. Development of the olfactory pathways in platypus and echidna.

    PubMed

    Ashwell, Ken W S

    2012-01-01

    The two groups of living monotremes (platypus and echidnas) have remarkably different olfactory structures in the adult. The layers of the main olfactory bulb of the short-beaked echidna are extensively folded, whereas those of the platypus are not. Similarly, the surface area of the piriform cortex of the echidna is large and its lamination complex, whereas in the platypus it is small and simple. It has been argued that the modern echidnas are derived from a platypus-like ancestor, in which case the extensive olfactory specializations of the modern echidnas would have developed relatively recently in monotreme evolution. In this study, the development of the constituent structures of the olfactory pathway was studied in sectioned platypus and echidna embryos and post-hatchlings at the Museum für Naturkunde, Berlin, Germany. The aim was to determine whether the olfactory structures follow a similar maturational path in the two monotremes during embryonic and early post-hatching ages or whether they show very different developmental paths from the outset. The findings indicate that anatomical differences in the central olfactory system between the short-beaked echidna and the platypus begin to develop immediately before hatching, although details of differences in nasal cavity architecture emerge progressively during late post-hatching life. These findings are most consistent with the proposition that the two modern monotreme lineages have followed independent evolutionary paths from a less olfaction-specialized ancestor. The monotreme olfactory pathway does not appear to be sufficiently structurally mature at birth to allow olfaction-mediated behaviour, because central components of both the main and accessory olfactory system have not differentiated at the time of hatching.

  1. Deep Sequencing of the Murine Olfactory Receptor Neuron Transcriptome

    PubMed Central

    Kanageswaran, Ninthujah; Demond, Marilen; Nagel, Maximilian; Schreiner, Benjamin S. P.; Baumgart, Sabrina; Scholz, Paul; Altmüller, Janine; Becker, Christian; Doerner, Julia F.; Conrad, Heike; Oberland, Sonja; Wetzel, Christian H.; Neuhaus, Eva M.; Hatt, Hanns; Gisselmann, Günter

    2015-01-01

    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. PMID:25590618

  2. Diverse Representations of Olfactory Information in Centrifugal Feedback Projections

    PubMed Central

    Osakada, Fumitaka; Tarabrina, Anna; Kizer, Erin; Callaway, Edward M.; Gage, Fred H.; Sejnowski, Terrence J.

    2016-01-01

    Although feedback or centrifugal projections from higher processing centers of the brain to peripheral regions have long been known to play essential functional roles, the anatomical organization of these connections remains largely unknown. Using a virus-based retrograde labeling strategy and 3D whole-brain reconstruction methods, we mapped the spatial organization of centrifugal projections from two olfactory cortical areas, the anterior olfactory nucleus (AON) and the piriform cortex, to the granule cell layer of the main olfactory bulb in the mouse. Both regions are major recipients of information from the bulb and are the largest sources of feedback to the bulb, collectively constituting circuits essential for olfactory coding and olfactory behavior. We found that, although ipsilateral inputs from the AON were uniformly distributed, feedback from the contralateral AON had a strong ventral bias. In addition, we observed that centrifugally projecting neurons were spatially clustered in the piriform cortex, in contrast to the distributed feedforward axonal inputs that these cells receive from the principal neurons of the bulb. Therefore, information carried from the bulb to higher processing structures by anatomically stereotypic projections is likely relayed back to the bulb by organizationally distinct feedback projections that may reflect different coding strategies and therefore different functional roles. SIGNIFICANCE STATEMENT Principles of anatomical organization, sometimes instantiated as “maps” in the mammalian brain, have provided key insights into the structure and function of circuits in sensory systems. Generally, these characterizations focus on projections from early sensory processing areas to higher processing structures despite considerable evidence that feedback or centrifugal projections often constitute major conduits of information flow. Our results identify structure in the organization of centrifugal feedback projections to the

  3. Restricted Stimulus Control in Stimulus Control Shaping with a Capuchin Monkey

    PubMed Central

    Brino, Ana Leda F.; Galvão, Olavo F.; Barros, Romariz S.; Goulart, Paulo R. K.; McIlvane, William J.

    2014-01-01

    Teaching the first instances of arbitrary matching to sample to nonhumans can prove difficult and time consuming. Stimulus control relations may develop that differ from those intended by the experimenter – even when stimulus control shaping procedures are used. This paper reports efforts to identify sources of shaping program failure with a capuchin monkey. Procedures began with a baseline of identity matching. During subsequent shaping trials, compound comparison stimuli had two components – one identical to and another different from the sample. The identical component was eliminated gradually by removing portions across trials (i.e., subtracting stimulus elements). The monkey performed accurately throughout shaping. At a late stage in the program, probe tests were conducted: (1) arbitrary matching trials that had all elements of the identical comparison removed and (2) other trials that included residual elements. During the test, the monkey performed at low levels on the former trials and higher levels on the latter. These results suggested that higher accuracy was due merely to continued control by the residual elements: the target arbitrary matching relations had not been learned. Thus, it appears that procedures that gradually transform identity matching baselines into arbitrary matching can fail by inadvertently shaping restricted control by residual elements. Subsequent probes at the end of the shaping series showed a successful transfer of stimulus control from identity to arbitrary matching after further programming steps apparently overcame the restricted stimulus control. PMID:24817994

  4. Sample Stimulus Control Shaping and Restricted Stimulus Control in Capuchin Monkeys: A Methodological Note

    PubMed Central

    Brino, Ana Leda F; Barros, Romariz S; Galvão, Olavo F; Garotti, M; da Cruz, Ilara R. N; Santos, José R; Dube, William V; McIlvane, William J

    2011-01-01

    This paper reports use of sample stimulus control shaping procedures to teach arbitrary matching-to-sample to 2 capuchin monkeys (Cebus apella). The procedures started with identity matching-to-sample. During shaping, stimulus features of the sample were altered gradually, rendering samples and comparisons increasingly physically dissimilar. The objective was to transform identity matching into arbitrary matching (i.e., matching not based on common physical features of the sample and comparison stimuli). Experiment 1 used a two-comparison procedure. The shaping procedure was ultimately effective, but occasional high error rates at certain program steps inspired a follow-up study. Experiment 2 used the same basic approach, but with a three-comparison matching task. During shaping, the monkey performed accurately until the final steps of the program. Subsequent experimentation tested the hypothesis that the decrease in accuracy was due to restricted stimulus control by sample stimulus features that had not yet been changed in the shaping program. Results were consistent with this hypothesis, thus suggesting a new approach that may transform the sample stimulus control shaping procedure from a sometimes useful laboratory tool to a more general approach to teaching the first instance of arbitrary matching performances to participants who show protracted difficulties in learning such performances. PMID:21547073

  5. Sample stimulus control shaping and restricted stimulus control in capuchin monkeys: a methodological note.

    PubMed

    Brino, Ana Leda F; Barros, Romariz S; Galvão, Olavo F; Garotti, M; da Cruz, Ilara R N; Santos, José R; Dube, William V; McIlvane, William J

    2011-05-01

    This paper reports use of sample stimulus control shaping procedures to teach arbitrary matching-to-sample to 2 capuchin monkeys (Cebus apella). The procedures started with identity matching-to-sample. During shaping, stimulus features of the sample were altered gradually, rendering samples and comparisons increasingly physically dissimilar. The objective was to transform identity matching into arbitrary matching (i.e., matching not based on common physical features of the sample and comparison stimuli). Experiment 1 used a two-comparison procedure. The shaping procedure was ultimately effective, but occasional high error rates at certain program steps inspired a follow-up study. Experiment 2 used the same basic approach, but with a three-comparison matching task. During shaping, the monkey performed accurately until the final steps of the program. Subsequent experimentation tested the hypothesis that the decrease in accuracy was due to restricted stimulus control by sample stimulus features that had not yet been changed in the shaping program. Results were consistent with this hypothesis, thus suggesting a new approach that may transform the sample stimulus control shaping procedure from a sometimes useful laboratory tool to a more general approach to teaching the first instance of arbitrary matching performances to participants who show protracted difficulties in learning such performances.

  6. Glomerular interactions in olfactory processing channels of the antennal lobes

    PubMed Central

    Heinbockel, Thomas; Shields, Vonnie D. C.; Reisenman, Carolina E.

    2014-01-01

    An open question in olfactory coding is the extent of interglomerular connectivity: do olfactory glomeruli and their neurons regulate the odorant responses of neurons innervating other glomeruli? In the olfactory system of the moth Manduca sexta, the response properties of different types of antennal olfactory receptor cells are known. Likewise, a subset of antennal lobe glomeruli has been functionally characterized and the olfactory tuning of their innervating neurons identified. This provides a unique opportunity to determine functional interactions between glomeruli of known input, specifically, (1) glomeruli processing plant odors and (2) glomeruli activated by antennal stimulation with pheromone components of conspecific females. Several studies describe reciprocal inhibitory effects between different types of pheromone-responsive projection neurons suggesting lateral inhibitory interactions between pheromone component-selective glomerular neural circuits. Furthermore, antennal lobe projection neurons that respond to host plant volatiles and innervate single, ordinary glomeruli are inhibited during antennal stimulation with the female’s sex pheromone. The studies demonstrate the existence of lateral inhibitory effects in response to behaviorally significant odorant stimuli and irrespective of glomerular location in the antennal lobe. Inhibitory interactions are present within and between olfactory subsystems (pheromonal and non-pheromonal subsystems), potentially to enhance contrast and strengthen odorant discrimination. PMID:23893248

  7. Dual olfactory pathway in Hymenoptera: evolutionary insights from comparative studies.

    PubMed

    Rössler, Wolfgang; Zube, Christina

    2011-07-01

    In the honeybee (Apis mellifera) and carpenter ant (Camponotus floridanus) the antennal lobe output is connected to higher brain centers by a dual olfactory pathway. Two major sets of uniglomerular projection neurons innervate glomeruli from two antennal-lobe hemispheres and project via a medial and a lateral antennal-lobe protocerebral tract in opposite sequence to the mushroom bodies and lateral horn. Comparison across insects suggests that the lateral projection neuron tract represents a special feature of Hymenoptera. We hypothesize that this promotes advanced olfactory processing associated with chemical communication, orientation and social interactions. To test whether a dual olfactory pathway is restricted to social Hymenoptera, we labeled the antennal lobe output tracts in selected species using fluorescent tracing and confocal imaging. Our results show that a dual pathway from the antennal lobe to the mushroom bodies is present in social bees, basal and advanced ants, solitary wasps, and in one of two investigated species of sawflies. This indicates that a dual olfactory pathway is not restricted to social species and may have evolved in basal Hymenoptera. We suggest that associated advances in olfactory processing represent a preadaptation for life styles with high demands on olfactory discrimination like parasitoism, central place foraging, and sociality.

  8. Basal forebrain dynamics during nonassociative and associative olfactory learning.

    PubMed

    Devore, Sasha; Pender-Morris, Nathaniel; Dean, Owen; Smith, David; Linster, Christiane

    2016-01-01

    Cholinergic and GABAergic projections from the horizontal diagonal band (HDB) and medial preoptic area (MCPO) of the basal forebrain to the olfactory system are associated with odor discrimination and odor learning, as well as modulation of neural responses in olfactory structures. Whereas pharmacological and lesion studies give insights into the functional role of these modulatory inputs on a slow timescale, the response dynamics of neurons in the HDB/MCPO during olfactory behaviors have not been investigated. In this study we examined how these neurons respond during two olfactory behaviors: spontaneous investigation of odorants and odor-reward association learning. We observe rich heterogeneity in the response dynamics of individual HDB/MCPO neurons, with a substantial fraction of neurons exhibiting task-related modulation. HDB/MCPO neurons show both rapid and transient responses during bouts of odor investigation and slow, long-lasting modulation of overall response rate based on behavioral demands. Specifically, baseline rates were higher during the acquisition phase of an odor-reward association than during spontaneous investigation or the recall phase of an odor reward association. Our results suggest that modulatory projections from the HDB/MCPO are poised to influence olfactory processing on multiple timescales, from hundreds of milliseconds to minutes, and are therefore capable of rapidly setting olfactory network dynamics during odor processing and learning.

  9. Illuminating odors: when optogenetics brings to light unexpected olfactory abilities

    PubMed Central

    Grimaud, Julien

    2016-01-01

    For hundreds of years, the sense of smell has generated great interest in the world literature, oenologists, and perfume makers but less of scientists. Only recently this sensory modality has gained new attraction in neuroscience when original tools issued from physiology, anatomy, or molecular biology were available to decipher how the brain makes sense of olfactory cues. However, this move was promptly dampened by the difficulties of developing quantitative approaches to study the relationship between the physical characteristics of stimuli and the sensations they create. An upswing of olfactory investigations occurred when genetic tools could be used in combination with devices borrowed from the physics of light (a hybrid technique called optogenetics) to scrutinize the olfactory system and to provide greater physiological precision for studying olfactory-driven behaviors. This review aims to present the most recent studies that have used light to activate components of the olfactory pathway, such as olfactory receptor neurons, or neurons located further downstream, while leaving intact others brain circuits. With the use of optogenetics to unravel the mystery of olfaction, scientists have begun to disentangle how the brain makes sense of smells. In this review, we shall discuss how the brain recognizes odors, how it memorizes them, and how animals make decisions based on odorants they are capable of sensing. Although this review deals with olfaction, the role of light will be central throughout. PMID:27194792

  10. Basal forebrain dynamics during nonassociative and associative olfactory learning

    PubMed Central

    Devore, Sasha; Pender-Morris, Nathaniel; Dean, Owen; Smith, David

    2015-01-01

    Cholinergic and GABAergic projections from the horizontal diagonal band (HDB) and medial preoptic area (MCPO) of the basal forebrain to the olfactory system are associated with odor discrimination and odor learning, as well as modulation of neural responses in olfactory structures. Whereas pharmacological and lesion studies give insights into the functional role of these modulatory inputs on a slow timescale, the response dynamics of neurons in the HDB/MCPO during olfactory behaviors have not been investigated. In this study we examined how these neurons respond during two olfactory behaviors: spontaneous investigation of odorants and odor-reward association learning. We observe rich heterogeneity in the response dynamics of individual HDB/MCPO neurons, with a substantial fraction of neurons exhibiting task-related modulation. HDB/MCPO neurons show both rapid and transient responses during bouts of odor investigation and slow, long-lasting modulation of overall response rate based on behavioral demands. Specifically, baseline rates were higher during the acquisition phase of an odor-reward association than during spontaneous investigation or the recall phase of an odor reward association. Our results suggest that modulatory projections from the HDB/MCPO are poised to influence olfactory processing on multiple timescales, from hundreds of milliseconds to minutes, and are therefore capable of rapidly setting olfactory network dynamics during odor processing and learning. PMID:26561601

  11. The sea lamprey has a primordial accessory olfactory system

    PubMed Central

    2013-01-01

    Background A dual olfactory system, represented by two anatomically distinct but spatially proximate chemosensory epithelia that project to separate areas of the forebrain, is known in several classes of tetrapods. Lungfish are the earliest evolving vertebrates known to have this dual system, comprising a main olfactory and a vomeronasal system (VNO). Lampreys, a group of jawless vertebrates, have a single nasal capsule containing two anatomically distinct epithelia, the main (MOE) and the accessory olfactory epithelia (AOE). We speculated that lamprey AOE projects to specific telencephalic regions as a precursor to the tetrapod vomeronasal system. Results To test this hypothesis, we characterized the neural circuits and molecular profiles of the accessory olfactory epithelium in the sea lamprey (Petromyzon marinus). Neural tract-tracing revealed direct and reciprocal connections with the dorsomedial telencephalic neuropil (DTN) which in turn projects directly to the dorsal pallium and the rostral hypothalamus. High-throughput sequencing demonstrated that the main and the accessory olfactory epithelia have virtually identical profiles of expressed genes. Real time quantitative PCR confirmed expression of representatives of all 3 chemoreceptor gene families identified in the sea lamprey genome. Conclusion Anatomical and molecular evidence shows that the sea lamprey has a primordial accessory olfactory system that may serve a chemosensory function. PMID:23957559

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

    PubMed Central

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

    2012-01-01

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

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

    SciTech Connect

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

    1994-11-01

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

  14. Imaging Odor-Evoked Activities in the Mouse Olfactory Bulb using Optical Reflectance and Autofluorescence Signals

    PubMed Central

    Chery, Romain; L'Heureux, Barbara; Bendahmane, Mounir; Renaud, Rémi; Martin, Claire; Pain, Frédéric; Gurden, Hirac

    2011-01-01

    In the brain, sensory stimulation activates distributed populations of neurons among functional modules which participate to the coding of the stimulus. Functional optical imaging techniques are advantageous to visualize the activation of these modules in sensory cortices with high spatial resolution. In this context, endogenous optical signals that arise from molecular mechanisms linked to neuroenergetics are valuable sources of contrast to record spatial maps of sensory stimuli over wide fields in the rodent brain. Here, we present two techniques based on changes of endogenous optical properties of the brain tissue during activation. First the intrinsic optical signals (IOS) are produced by a local alteration in red light reflectance due to: (i) absorption by changes in blood oxygenation level and blood volume (ii) photon scattering. The use of in vivo IOS to record spatial maps started in the mid 1980's with the observation of optical maps of whisker barrels in the rat and the orientation columns in the cat visual cortex1. IOS imaging of the surface of the rodent main olfactory bulb (OB) in response to odorants was later demonstrated by Larry Katz's group2. The second approach relies on flavoprotein autofluorescence signals (FAS) due to changes in the redox state of these mitochondrial metabolic intermediates. More precisely, the technique is based on the green fluorescence due to oxidized state of flavoproteins when the tissue is excited with blue light. Although such signals were probably among the first fluorescent molecules recorded for the study of brain activity by the pioneer studies of Britton Chances and colleagues3, it was not until recently that they have been used for mapping of brain activation in vivo. FAS imaging was first applied to the somatosensory cortex in rodents in response to hindpaw stimulation by Katsuei Shibuki's group4. The olfactory system is of central importance for the survival of the vast majority of living species because it

  15. Stimulus devaluation induced by stopping action.

    PubMed

    Wessel, Jan R; O'Doherty, John P; Berkebile, Michael M; Linderman, David; Aron, Adam R

    2014-12-01

    Impulsive behavior in humans partly relates to inappropriate overvaluation of reward-associated stimuli. Hence, it is desirable to develop methods of behavioral modification that can reduce stimulus value. Here, we tested whether one kind of behavioral modification--the rapid stopping of actions in the face of reward-associated stimuli--could lead to subsequent devaluation of those stimuli. We developed a novel paradigm with three consecutive phases: implicit reward learning, a stop-signal task, and an auction procedure. In the learning phase, we associated abstract shapes with different levels of reward. In the stop-signal phase, we paired half those shapes with occasional stop-signals, requiring the rapid stopping of an initiated motor response, while the other half of shapes was not paired with stop signals. In the auction phase, we assessed the subjective value of each shape via willingness-to-pay. In 2 experiments, we found that participants bid less for shapes that were paired with stop-signals compared to shapes that were not. This suggests that the requirement to try to rapidly stop a response decrements stimulus value. Two follow-on control experiments suggested that the result was specifically due to stopping action rather than aversiveness, effort, conflict, or salience associated with stop signals. This study makes a theoretical link between research on inhibitory control and value. It also provides a novel behavioral paradigm with carefully operationalized learning, treatment, and valuation phases. This framework lends itself to both behavioral modification procedures in clinical disorders and research on the neural underpinnings of stimulus devaluation.

  16. Teaching braille line tracking using stimulus fading.

    PubMed

    Scheithauer, Mindy C; Tiger, Jeffrey H

    2014-01-01

    Line tracking is a prerequisite skill for braille literacy that involves moving one's finger horizontally across a line of braille text and identifying when a line ends so the reader may reset his or her finger on the subsequent line. Current procedures for teaching line tracking are incomplete, because they focus on tracking lines with only small gaps between characters. The current study extended previous line-tracking instruction using stimulus fading to teach tracking across larger gaps. After instruction, all participants showed improvement in line tracking, and 2 of 3 participants met mastery criteria for tracking across extended spaces.

  17. Discriminative stimulus effects of nicotine in humans.

    PubMed

    Perkins, Kenneth A

    2009-01-01

    Behavioral discrimination procedures clearly demonstrate that nicotine elicits interoceptive stimulus effects in humans that are malleable by various pharmacological manipulations as well as by some behavioral manipulations. The parameters of nicotine discrimination and both chronic and acute factors that may alter discrimination behavior are addressed in this chapter, which emphasizes research by the author involving nicotine delivered by nasal spray. Human discrimination of nicotine is centrally mediated, as the central and peripheral nicotine antagonist mecamylamine blocks discrimination but the peripheral antagonist trimethaphan does not. The threshold dose for discrimination of nicotine via spray appears to be very low in smokers as well as nonsmokers. Because smoked tobacco delivers nicotine more rapidly than spray, the threshold dose of nicotine via smoking is probably even lower. In terms of individual differences, smokers may become tolerant to the discriminative stimulus effects of higher nicotine doses but not of low doses. Men may be more sensitive than women to nicotine's discriminative stimulus effects, consistent with other research suggesting that nicotine is more reinforcing in men than in women. Other potential individual differences in nicotine discrimination have not been clearly tested, but may include genetics, obesity, and dependence on other drugs. Acute environmental factors that alter nicotine discrimination include the specific training and testing conditions, pointing to the need for careful control over such conditions during research. Other factors, such as concurrent acute use of alcohol or caffeine, do not appear to alter nicotine discrimination, suggesting that changes in nicotine discrimination are not likely explanations for the association of smoking behavior with use of those drugs. Concurrent physical activity also does not appear to alter nicotine discrimination, indicating that results from studies of discrimination in

  18. Economic Stimulus Proposals for 2008: An Analysis

    DTIC Science & Technology

    2008-02-01

    provide broader support for the economy than monetary policy actions alone.” Quoted in Ben Bernanke , “The Economic Outlook,” testimony before the House...limit for mortgages from $417,000 up to $729,750 in high-cost areas. The need for fiscal stimulus depends, by definition, on the state of the economy ...While the economy is not officially in a recession at present, there are signs that economic activity may be slowing. Some economists are predicting

  19. Stimulus-parity synaesthesia versus stimulus-dichotomy synaesthesia: Odd, even or something else?

    PubMed

    White, Rebekah C; Plassart, Anna

    2015-01-01

    In stimulus-parity synaesthesia, a range of stimuli-for example, letters, numbers, weekdays, months, and colours (the inducers)-elicit an automatic feeling of oddness or evenness (the concurrent). This phenomenon was first described by Théodore Flournoy in 1893, and has only recently been "rediscovered." Here, we describe an individual who experiences a comparable phenomenon, but uses the labels negative and positive rather than odd and even. Stimulus-parity synaesthesia may be broader than first supposed, and it is important that assessments are sensitive to this breadth.

  20. Ultrastructural analysis of olfactory ensheathing cells derived from olfactory bulb and nerve of neonatal and juvenile rats.

    PubMed

    Gómez, Rosa M; Ghotme, Kemel; Botero, Lucía; Bernal, Jaime E; Pérez, Rosalía; Barreto, George E; Bustos, Rosa Helena

    2016-02-01

    Olfactory nerve derived and olfactory bulb derived olfactory ensheathing cells (OECs) have the ability to promote axonal regeneration and remyelination, both of which are essential in a successful cell transplant. Thus, morphological identification of OECs is a key aspect to develop an applicable cell therapy for injuries to the nervous system. However, there is no clear definition regarding which developmental stage or anatomical origin of OECs is more adequate for neural repair. In the present study, an ultrastructural comparison was made between OECs recovered from primary cultures of olfactory nerve and bulb in two developmental stages. The most notorious difference between cells obtained from olfactory nerve and bulb was the presence of indented nuclei in bulb derived OECs, suggesting a greater ability for possible chemotaxis. In neonatal OECs abundant mitochondria, lipid vacuoles, and smooth endoplasmic reticulum were detected, suggesting an active lipid metabolism, probably involved in synthesis of myelin. Our results suggest that neonatal OECs obtained from olfactory bulb have microscopic properties that could make them more suitable for neural repair.

  1. Stimulus control topography coherence theory: Foundations and extensions

    PubMed Central

    McIlvane, William J.; Dube, William V.

    2003-01-01

    Stimulus control topography refers to qualitative differences among members of a functional stimulus class. Stimulus control topography coherence refers to the degree of concordance between the stimulus properties specified as relevant by the individual arranging a reinforcement contingency (behavior analyst, experimenter, teacher, etc.) and the stimulus properties that come to control the behavior of the organism (experimental subject, student, etc.) that experiences those contingencies. This paper summarizes the rationale for analyses of discrimination learning outcomes in terms of stimulus control topography coherence and briefly reviews some of the foundational studies that led to this perspective. We also suggest directions for future research, including pursuit of conceptual and methodological challenges to a complete stimulus control topography coherence analysis of processes involved in discriminated and generalized operants. ImagesFigure 3Figure 5 PMID:22478402

  2. Infusions of muscimol into the lateral septum do not reduce rats' defensive behaviors toward a cat odor stimulus.

    PubMed

    Chee, San-San A; Patel, Ronak; Menard, Janet L

    2015-01-01

    The lateral septum (LS) is implicated in behavioral defense. We tested whether bilateral infusions of the GABAA receptor agonist muscimol into the LS suppress rats' defensive responses to cat odor. Rats received intra-LS infusions of either saline or muscimol (40 ng/rat) and were exposed to either a piece of a cat collar that had been previously worn by a cat or to a control (cat odor free) collar. Rats exposed to the cat odor collar displayed more head-out postures, while intra-LS application of muscimol reduced the number of head-out postures. However, this reduction was also present in rats exposed to a control (cat odor free) collar. This latter finding suggests that despite its involvement in other defensive behaviors (e.g., open arm avoidance in the elevated plus maze), the LS does not selectively regulate rats' receptor defensive responding to the olfactory cues present in our cat odor stimulus.

  3. Identification and Comparison of Candidate Olfactory Genes in the Olfactory and Non-Olfactory Organs of Elm Pest Ambrostoma quadriimpressum (Coleoptera: Chrysomelidae) Based on Transcriptome Analysis

    PubMed Central

    Wang, Yinliang; Chen, Qi; Zhao, Hanbo; Ren, Bingzhong

    2016-01-01

    The leaf beetle Ambrostoma quadriimpressum (Coleoptera: Chrysomelidae) is a predominant forest pest that causes substantial damage to the lumber industry and city management. However, no effective and environmentally friendly chemical method has been discovered to control this pest. Until recently, the molecular basis of the olfactory system in A. quadriimpressum was completely unknown. In this study, antennae and leg transcriptomes were analyzed and compared using deep sequencing data to identify the olfactory genes in A. quadriimpressum. Moreover, the expression profiles of both male and female candidate olfactory genes were analyzed and validated by bioinformatics, motif analysis, homology analysis, semi-quantitative RT-PCR and RT-qPCR experiments in antennal and non-olfactory organs to explore the candidate olfactory genes that might play key roles in the life cycle of A. quadriimpressum. As a result, approximately 102.9 million and 97.3 million clean reads were obtained from the libraries created from the antennas and legs, respectively. Annotation led to 34344 Unigenes, which were matched to known proteins. Annotation data revealed that the number of genes in antenna with binding functions and receptor activity was greater than that of legs. Furthermore, many pathway genes were differentially expressed in the two organs. Sixteen candidate odorant binding proteins (OBPs), 10 chemosensory proteins (CSPs), 34 odorant receptors (ORs), 20 inotropic receptors [1] and 2 sensory neuron membrane proteins (SNMPs) and their isoforms were identified. Additionally, 15 OBPs, 9 CSPs, 18 ORs, 6 IRs and 2 SNMPs were predicted to be complete ORFs. Using RT-PCR, RT-qPCR and homology analysis, AquaOBP1/2/4/7/C1/C6, AquaCSP3/9, AquaOR8/9/10/14/15/18/20/26/29/33, AquaIR8a/13/25a showed olfactory-specific expression, indicating that these genes might play a key role in olfaction-related behaviors in A. quadriimpressum such as foraging and seeking. AquaOBP4/C5, AquaOBP4/C5, AquaCSP7

  4. Olfactory cleft computed tomography analysis and olfaction in chronic rhinosinusitis

    PubMed Central

    Kohli, Preeti; Schlosser, Rodney J.; Storck, Kristina

    2016-01-01

    Background: Volumetric analysis of the olfactory cleft by using computed tomography has been associated with olfaction in patients with chronic rhinosinusitis (CRS). However, existing studies have not comprehensively measured olfaction, and it thus remains unknown whether correlations differ across specific dimensions of odor perception. Objective: To use comprehensive measures of patient-reported and objective olfaction to evaluate the relationship between volumetric olfactory cleft opacification and olfaction. Methods: Olfaction in patients with CRS was evaluated by using “Sniffin' Sticks” tests and a modified version of the Questionnaire of Olfactory Disorders. Olfactory cleft opacification was quantified by using two- and three-dimensional, computerized volumetric analysis. Correlations between olfactory metrics and olfactory cleft opacification were then calculated. Results: The overall CRS cohort included 26 patients without nasal polyposis (CRSsNP) (68.4%) and 12 patients with nasal polyposis (CRSwNP) (31.6%). Across the entire cohort, total olfactory cleft opacification was 82.8%, with greater opacification in the CRSwNP subgroup compared with CRSsNP (92.3 versus 78.4%, p < 0.001). The percent total volume opacification correlated with the total Sniffin' Sticks score (r = −0.568, p < 0.001) as well as individual threshold, discrimination, and identification scores (p < 0.001 for all). Within the CRSwNP subgroup, threshold (r = −0.616, p = 0.033) and identification (r = −0.647, p = 0.023) remained highly correlated with total volume opacification. In patients with CRSsNP, the threshold correlated with total volume scores (r = −0.457, p = 0.019), with weaker and nonsignificant correlations for discrimination and identification. Correlations between total volume opacification and the Questionnaire of Olfactory Disorders were qualitatively similar to objective olfactory findings in both CRSwNP (r = −0.566, p = 0.070) and CRSsNP (r = −0.310, p

  5. Antennal lobe representations are optimized when olfactory stimuli are periodically structured to simulate natural wing beat effects

    PubMed Central

    Houot, Benjamin; Burkland, Rex; Tripathy, Shreejoy; Daly, Kevin C.

    2014-01-01

    Animals use behaviors to actively sample the environment across a broad spectrum of sensory domains. These behaviors discretize the sensory experience into unique spatiotemporal moments, minimize sensory adaptation, and enhance perception. In olfaction, behaviors such as sniffing, antennal flicking, and wing beating all act to periodically expose olfactory epithelium. In mammals, it is thought that sniffing enhances neural representations; however, the effects of insect wing beating on representations remain unknown. To determine how well the antennal lobe (AL) produces odor dependent representations when wing beating effects are simulated, we used extracellular methods to record neural units and local field potentials (LFPs) from moth AL. We recorded responses to odors presented as prolonged continuous stimuli or periodically as 20 and 25 Hz pulse trains designed to simulate the oscillating effects of wing beating around the antennae during odor guided flight. Using spectral analyses, we show that ~25% of all recorded units were able to entrain to “pulsed stimuli”; this includes pulsed blanks, which elicited the strongest overall entrainment. The strength of entrainment to pulse train stimuli was dependent on molecular features of the odorants, odor concentration, and pulse train duration. Moreover, units showing pulse tracking responses were highly phase locked to LFPs during odor stimulation, indicating that unit-LFP phase relationships are stimulus-driven. Finally, a Euclidean distance-based population vector analysis established that AL odor representations are more robust, peak more quickly, and do not show adaptation when odors were presented at the natural wing beat frequency as opposed to prolonged continuous stimulation. These results suggest a general strategy for optimizing olfactory representations, which exploits the natural rhythmicity of wing beating by integrating mechanosensory and olfactory cues at the level of the AL. PMID:24971052

  6. SNP genotypes of olfactory receptor genes associated with olfactory ability in German Shepherd dogs.

    PubMed

    Yang, M; Geng, G-J; Zhang, W; Cui, L; Zhang, H-X; Zheng, J-L

    2016-04-01

    To find out the relationship between SNP genotypes of canine olfactory receptor genes and olfactory ability, 28 males and 20 females from German Shepherd dogs in police service were scored by odor detection tests and analyzed using the Beckman GenomeLab SNPstream. The representative 22 SNP loci from the exonic regions of 12 olfactory receptor genes were investigated, and three kinds of odor (human, ice drug and trinitrotoluene) were detected. The results showed that the SNP genotypes at the OR10H1-like:c.632C>T, OR10H1-like:c.770A>T, OR2K2-like:c.518G>A, OR4C11-like:c.511T>G and OR4C11-like:c.692G>A loci had a statistically significant effect on the scenting abilities (P < 0.001). The kind of odor influenced the performances of the dogs (P < 0.001). In addition, there were interactions between genotype and the kind of odor at the following loci: OR10H1-like:c.632C>T, OR10H1-like:c.770A>T, OR4C11-like:c.511T>G and OR4C11-like:c.692G>A (P < 0.001). The dogs with genotype CC at the OR10H1-like:c.632C>T, genotype AA at the OR10H1-like:c.770A>T, genotype TT at the OR4C11-like:c.511T>G and genotype GG at the OR4C11-like:c.692G>A loci did better at detecting the ice drug. We concluded that there was linkage between certain SNP genotypes and the olfactory ability of dogs and that SNP genotypes might be useful in determining dogs' scenting potential.

  7. Multisensory temporal integration: Task and stimulus dependencies

    PubMed Central

    Stevenson, Ryan A.; Wallace, Mark T.

    2013-01-01

    The ability of human sensory systems to integrate information across the different modalities provides a wide range of behavioral and perceptual benefits. This integration process is dependent upon the temporal relationship of the different sensory signals, with stimuli occurring close together in time typically resulting in the largest behavior changes. The range of temporal intervals over which such benefits are seen is typically referred to as the temporal binding window (TBW). Given the importance of temporal factors in multisensory integration under both normal and atypical circumstances such as autism and dyslexia, the TBW has been measured with a variety of experimental protocols that differ according to criterion, task, and stimulus type, making comparisons across experiments difficult. In the current study we attempt to elucidate the role that these various factors play in the measurement of this important construct. The results show a strong effect of stimulus type, with the TBW assessed with speech stimuli being both larger and more symmetrical than that seen using simple and complex non-speech stimuli. These effects are robust across task and statistical criteria, and are highly consistent within individuals, suggesting substantial overlap in the neural and cognitive operations that govern multisensory temporal processes. PMID:23604624

  8. Nonlinear adaptive filtering of stimulus artifact.

    PubMed

    Grieve, R; Parker, P A; Hudgins, B; Englehart, K

    2000-03-01

    Noninvasive measurements of somatosensory evoked potentials have both clinical and research applications. The electrical artifact which results from the stimulus is an interference which can distort the evoked signal, and introduce errors in response onset timing estimation. Given that this interference is synchronous with the evoked signal, it cannot be reduced by the conventional technique of ensemble averaging. The technique of adaptive noise cancelling has potential in this regard however, and has been used effectively in other similar problems. An adaptive noise cancelling filter which uses a neural network as the adaptive element is investigated in this application. The filter is implemented and performance determined in the cancelling of artifact for in vivo measurements on the median nerve. A technique of segmented neural network training is proposed in which the network is trained on that segment of the record time window which does not contain the evoked signal. The neural network is found to generalize well from this training to include the segment of the window containing the evoked signal. Both quantitative and qualitative measures show that significant stimulus artifact reduction is achieved.

  9. Quantification of a contact stimulus by diapers

    NASA Astrophysics Data System (ADS)

    Nomata, Takuya; Okuyama, Takeshi; Teraoka, Hiromi; Murakami, Yasuo; Miyazawa, Kiyoshi; Tanaka, Mami

    2010-01-01

    This paper describes a development of a sensor system for measurement of a contact stimulus which diapers give to infants. A polyvinyliden fluoride (PVDF) film and a strain gauge are used as the sensor receptors. The PVDF is a kind of piezoelectric material. The sensor consists of a surface contact layer, a PVDF film, a strain gauge and an aluminum plate. First, in order to investigate the sensor performance, the sensor was located on a silicone plate and the upper part of the sensor was rubbed with an acrylic artificial finger. The finger enabled the measurement to carry out at a constant speed and force. Next, the sensor was attached on an infant dummy and the sensor outputs were measured under conditions with and without diapers. By comparison of the output under two different conditions, it was confirmed that there is a clearly difference between the two conditions. It was found that the developed sensor system has the possibility to quantify a contact stimulus which diapers give infants.

  10. Quantification of a contact stimulus by diapers

    NASA Astrophysics Data System (ADS)

    Nomata, Takuya; Okuyama, Takeshi; Teraoka, Hiromi; Murakami, Yasuo; Miyazawa, Kiyoshi; Tanaka, Mami

    2009-12-01

    This paper describes a development of a sensor system for measurement of a contact stimulus which diapers give to infants. A polyvinyliden fluoride (PVDF) film and a strain gauge are used as the sensor receptors. The PVDF is a kind of piezoelectric material. The sensor consists of a surface contact layer, a PVDF film, a strain gauge and an aluminum plate. First, in order to investigate the sensor performance, the sensor was located on a silicone plate and the upper part of the sensor was rubbed with an acrylic artificial finger. The finger enabled the measurement to carry out at a constant speed and force. Next, the sensor was attached on an infant dummy and the sensor outputs were measured under conditions with and without diapers. By comparison of the output under two different conditions, it was confirmed that there is a clearly difference between the two conditions. It was found that the developed sensor system has the possibility to quantify a contact stimulus which diapers give infants.

  11. Hospital Clowning as Play Stimulus in Healthcare.

    PubMed

    Anes, Laura; Obi, Marianne

    2014-10-30

    A serious illness, a chronic medical condition or a hospital bed should not deny any child her/his basic right to play, a right essential for children's development and general wellbeing. In fact, it is in these frightening and anxious moments that play and the stimulus that it provides can help the most. This article will focus on the impacts and benefits of professional hospital clowning for the wellbeing and recovery process of ill and hospitalized children. Our experience has shown that through interactive play and humor, "clowndoctors" can create an enabling and supportive environment that facilitates children's adaptation to the hospital setting and improves their acceptance of medical procedures and staff. While moving from bedside to bedside, RED NOSES clowndoctors encourage children's active participation and support their natural instinct to play, fully including them in the interaction, if the children wish to do so. Therefore, clowndoctor performances offer ill children much needed stimulus, self-confidence and courage, elements fundamental to reducing their vulnerability. In this piece, a special emphasis will be put on the various approaches used by RED NOSES clowndoctors to bond and reach out to children suffering from different medical conditions.

  12. Hospital Clowning as Play Stimulus in Healthcare

    PubMed Central

    Anes, Laura; Obi, Marianne

    2014-01-01

    A serious illness, a chronic medical condition or a hospital bed should not deny any child her/his basic right to play, a right essential for children’s development and general wellbeing. In fact, it is in these frightening and anxious moments that play and the stimulus that it provides can help the most. This article will focus on the impacts and benefits of professional hospital clowning for the wellbeing and recovery process of ill and hospitalized children. Our experience has shown that through interactive play and humor, “clowndoctors” can create an enabling and supportive environment that facilitates children’s adaptation to the hospital setting and improves their acceptance of medical procedures and staff. While moving from bedside to bedside, RED NOSES clowndoctors encourage children’s active participation and support their natural instinct to play, fully including them in the interaction, if the children wish to do so. Therefore, clowndoctor performances offer ill children much needed stimulus, self-confidence and courage, elements fundamental to reducing their vulnerability. In this piece, a special emphasis will be put on the various approaches used by RED NOSES clowndoctors to bond and reach out to children suffering from different medical conditions. PMID:27417485

  13. Stimulus effects on concurrent performance in transition

    PubMed Central

    Hanna, Elenice S.; Blackman, Derek E.; Todorov, João Claudio

    1992-01-01

    Six experimentally naive pigeons were exposed to concurrent variable-interval variable-interval schedules in a three-key procedure in which food reinforcement followed pecks on the side keys and pecks on the center key served as changeover responses. In Phase 1, 3 birds were exposed to 20 combinations of five variable-interval values, with each variable-interval value consistently associated with a different color on the side keys. Another 3 pigeons were exposed to the same 20 conditions, but with a more standard procedure that used a nondifferential discriminative stimulus on the two side keys throughout all conditions. In Phase 2, the differential and nondifferential stimulus conditions were reversed for each pigeon. Each condition lasted for one 5-hr session and one subsequent 1-hr session. In the last 14 conditions of each phase, the presence of differential discriminative stimuli decreased the time necessary for differential responding to develop and increased the sensitivity of behavior to reinforcement distribution in the 1st hr of training; during the last hours of training in each condition, however, the effects of the differential discriminative stimuli could not be distinguished from the effects of reinforcement distribution per se. These results show the importance of studying transitions in behavior as well as final performance. They may also be relevant to discrepancies in the results of previous experiments that have used nonhuman and human subjects. PMID:16812669

  14. Bigrams and the richness of the stimulus.

    PubMed

    Kam, Xuân-Nga Cao; Stoyneshka, Iglika; Tornyova, Lidiya; Fodor, Janet D; Sakas, William G

    2008-06-01

    Recent challenges to Chomsky's poverty of the stimulus thesis for language acquisition suggest that children's primary data may carry "indirect evidence" about linguistic constructions despite containing no instances of them. Indirect evidence is claimed to suffice for grammar acquisition, without need for innate knowledge. This article reports experiments based on those of Reali and Christiansen (2005), who demonstrated that a simple bigram language model can induce the correct form of auxiliary inversion in certain complex questions. This article investigates the nature of the indirect evidence that supports this learning, and assesses how reliably it is available. Results confirm the original finding for one specific sentence type but show that the model's success is highly circumscribed. It performs poorly on inversion in related constructions in English and Dutch. Because other, more powerful statistical models have so far been shown to succeed only on the same limited subset of cases as the bigram model, it remains to be seen whether stimulus richness can be substantiated more generally.

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

    PubMed

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

    2012-01-01

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

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

    PubMed Central

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

    2012-01-01

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

  17. Reduction in host-finding behaviour in fungus-infected mosquitoes is correlated with reduction in olfactory receptor neuron responsiveness

    PubMed Central

    2011-01-01

    Background Chemical insecticides against mosquitoes are a major component of malaria control worldwide. Fungal entomopathogens formulated as biopesticides and applied as insecticide residual sprays could augment current control strategies and mitigate the evolution of resistance to chemical-based insecticides. Methods Anopheles stephensi mosquitoes were exposed to Beauveria bassiana or Metarhizium acridum fungal spores and sub-lethal effects of exposure to fungal infection were studied, especially the potential for reductions in feeding and host location behaviours related to olfaction. Electrophysiological techniques, such as electroantennogram, electropalpogram and single sensillum recording techniques were then employed to investigate how fungal exposure affected the olfactory responses in mosquitoes. Results Exposure to B. bassiana caused significant mortality and reduced the propensity of mosquitoes to respond and fly to a feeding stimulus. Exposure to M. acridum spores induced a similar decline in feeding propensity, albeit more slowly than B. bassiana exposure. Reduced host-seeking responses following fungal exposure corresponded to reduced olfactory neuron responsiveness in both antennal electroantennogram and maxillary palp electropalpogram recordings. Single cell recordings from neurons on the palps confirmed that fungal-exposed behavioural non-responders exhibited significantly impaired responsiveness of neurons tuned specifically to 1-octen-3-ol and to a lesser degree, to CO2. Conclusions Fungal infection reduces the responsiveness of mosquitoes to host odour cues, both behaviourally and neuronally. These pre-lethal effects are likely to synergize with fungal-induced mortality to further reduce the capacity of mosquito populations exposed to fungal biopesticides to transmit malaria. PMID:21812944

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

    PubMed Central

    Thewissen, JGM; Usip, Sharon; Suydam, Robert S.; George, John C.

    2015-01-01

    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. PMID:25945304

  19. Silencing the Olfactory Co-Receptor RferOrco Reduces the Response to Pheromones in the Red Palm Weevil, Rhynchophorus ferrugineus

    PubMed Central

    Soffan, Alan; Abdelazim, Mahmoud; Shukla, Paraj; Witjaksono, Witjaksono; Aldosari, Saleh A.; Aldawood, Abdulrahman S.

    2016-01-01

    The red palm weevil (RPW, Rhynchophorus ferrugineus), one of the most widespread of all invasive insect pest species, is a major cause of severe damage to economically important palm trees. RPW exhibits behaviors very similar to those of its sympatric species, the Asian palm weevil (R. vulneratus), which is restricted geographically to the southern part of Southeast Asia. Although efficient and sustainable control of these pests remains challenging, olfactory-system disruption has been proposed as a promising approach for controlling palm weevils. Here, we report the cloning and sequencing of an olfactory co-receptor (Orco) from R. ferrugineus (RferOrco) and R. vulneratus (RvulOrco) and examine the effects of RferOrco silencing (RNAi) on odorant detection. RferOrco and RvulOrco encoding 482 amino acids showing 99.58% identity. The injection of double-stranded RNA (dsRNA) from RferOrco into R. ferrugineus pupae significantly reduced RferOrco gene expression and led to the failure of odor-stimulus detection, as confirmed through olfactometer and electroantennography (EAG) assays. These results suggest that olfactory-system disruption leading to reduced pheromone detection holds great potential for RPW pest-control strategies. PMID:27606688

  20. Silencing the Olfactory Co-Receptor RferOrco Reduces the Response to Pheromones in the Red Palm Weevil, Rhynchophorus ferrugineus.

    PubMed

    Soffan, Alan; Antony, Binu; Abdelazim, Mahmoud; Shukla, Paraj; Witjaksono, Witjaksono; Aldosari, Saleh A; Aldawood, Abdulrahman S

    2016-01-01

    The red palm weevil (RPW, Rhynchophorus ferrugineus), one of the most widespread of all invasive insect pest species, is a major cause of severe damage to economically important palm trees. RPW exhibits behaviors very similar to those of its sympatric species, the Asian palm weevil (R. vulneratus), which is restricted geographically to the southern part of Southeast Asia. Although efficient and sustainable control of these pests remains challenging, olfactory-system disruption has been proposed as a promising approach for controlling palm weevils. Here, we report the cloning and sequencing of an olfactory co-receptor (Orco) from R. ferrugineus (RferOrco) and R. vulneratus (RvulOrco) and examine the effects of RferOrco silencing (RNAi) on odorant detection. RferOrco and RvulOrco encoding 482 amino acids showing 99.58% identity. The injection of double-stranded RNA (dsRNA) from RferOrco into R. ferrugineus pupae significantly reduced RferOrco gene expression and led to the failure of odor-stimulus detection, as confirmed through olfactometer and electroantennography (EAG) assays. These results suggest that olfactory-system disruption leading to reduced pheromone detection holds great potential for RPW pest-control strategies.

  1. Early Olfactory Environment Influences Social Behaviour in Adult Octodon degus

    PubMed Central

    Márquez, Natalia; Martínez-Harms, Jaime; Vásquez, Rodrigo A.; Mpodozis, Jorge

    2015-01-01

    We evaluated the extent to which manipulation of early olfactory environment can influence social behaviours in the South American Hystricognath rodent Octodon degus. The early olfactory environment of newborn degus was manipulated by scenting all litter members with eucalyptol during the first month of life. The social behaviour of sexually mature animals (5–7 months old) towards conspecifics was then assessed using a y-maze to compare the response of control (naïve) and treated animals to two different olfactory configurations (experiment 1): (i) a non-familiarized conspecific impregnated with eucalyptol (eucalyptol arm) presented against (ii) a non-familiarized unscented conspecific (control arm). In addition, in dyadic encounters, we assessed the behaviour of control and eucalyptol treated animals towards a non-familiarized conspecific scented with eucalyptol (experiment 2). We found that control subjects explored and spent significantly less time in the eucalyptol arm, indicating neophobic behaviours towards the artificially scented conspecific. Treated subjects explored and spent similar time in both arms of the maze, showing the same interest for both olfactory stimuli presented. During dyadic encounters in experiment 2, an interaction effect between early experience and sex was observed. Control males escaped and avoided their scented partner more frequently than eucalyptol treated male subjects and than females. Both groups did not differ in the exploration of their scented partners, suggesting that avoidance within agonistic context does not relate to neophobic behaviours. Our results suggest that the exposure to eucalyptol during early ontogeny decreases evasive behaviours within an agonistic context as a result of olfactory learning. Altogether, these results indicate that olfactory cues learned in early ontogeny can influence olfactory-guided behaviours in adult degus. PMID:25671542

  2. Olfactory receptors are displayed on dog mature sperm cells

    PubMed Central

    1993-01-01

    Olfactory receptors constitute a huge family of structurally related G protein-coupled receptors, with up to a thousand members expected. We have shown previously that genes belonging to this family were expressed in the male germ line from both dog and human. The functional significance of this unexpected site of expression was further investigated in the present study. We demonstrate that a few dog genes representative of various subfamilies of olfactory receptors are expressed essentially in testis, with little or no expression in olfactory mucosa. Other randomly selected members of the family show the expected site of expression, restricted to the olfactory system. Antibodies were generated against the deduced amino acid sequence of the most abundantly expressed olfactory receptor gene in dog testis. The purified serum was able to detect the gene product (DTMT receptor) in late round and elongated spermatids, as well as in the cytoplasmic droplet that characterizes the maturation of dog sperm cells, and on the tail midpiece of mature spermatozoa. Western blotting further confirmed the presence of a 40-kD immunoreactive protein in the membrane of mature sperm cells. Altogether , these results demonstrate that the main expression site of a subset of the large olfactory receptor gene family is not olfactory mucosa but testis. This expression correlates with the presence of the corresponding protein during sperm cell maturation, and on mature sperm cells. The pattern of expression is consistent with a role as sensor for unidentified chemicals possibly involved in the control of mammalian sperm maturation, migration, and/or fertilization. PMID:8253843

  3. Using Insect Electroantennogram Sensors on Autonomous Robots for Olfactory Searches

    PubMed Central

    Martinez, Dominique; Arhidi, Lotfi; Demondion, Elodie; Masson, Jean-Baptiste; Lucas, Philippe

    2014-01-01

    Robots designed to track chemical leaks in hazardous industrial facilities1 or explosive traces in landmine fields2 face the same problem as insects foraging for food or searching for mates3: the olfactory search is constrained by the physics of turbulent transport4. The concentration landscape of wind borne odors is discontinuous and consists of sporadically located patches. A pre-requisite to olfactory search is that intermittent odor patches are detected. Because of its high speed and sensitivity5-6, the olfactory organ of insects provides a unique opportunity for detection. Insect antennae have been used in the past to detect not only sex pheromones7 but also chemicals that are relevant to humans, e.g., volatile compounds emanating from cancer cells8 or toxic and illicit substances9-11. We describe here a protocol for using insect antennae on autonomous robots and present a proof of concept for tracking odor plumes to their source. The global response of olfactory neurons is recorded in situ in the form of electroantennograms (EAGs). Our experimental design, based on a whole insect preparation, allows stable recordings within a working day. In comparison, EAGs on excised antennae have a lifetime of 2 hr. A custom hardware/software interface was developed between the EAG electrodes and a robot. The measurement system resolves individual odor patches up to 10 Hz, which exceeds the time scale of artificial chemical sensors12. The efficiency of EAG sensors for olfactory searches is further demonstrated in driving the robot toward a source of pheromone. By using identical olfactory stimuli and sensors as in real animals, our robotic platform provides a direct means for testing biological hypotheses about olfactory coding and search strategies13. It may also prove beneficial for detecting other odorants of interests by combining EAGs from different insect species in a bioelectronic nose configuration14 or using nanostructured gas sensors that mimic insect antennae15

  4. Using insect electroantennogram sensors on autonomous robots for olfactory searches.

    PubMed

    Martinez, Dominique; Arhidi, Lotfi; Demondion, Elodie; Masson, Jean-Baptiste; Lucas, Philippe

    2014-08-04

    Robots designed to track chemical leaks in hazardous industrial facilities or explosive traces in landmine fields face the same problem as insects foraging for food or searching for mates: the olfactory search is constrained by the physics of turbulent transport. The concentration landscape of wind borne odors is discontinuous and consists of sporadically located patches. A pre-requisite to olfactory search is that intermittent odor patches are detected. Because of its high speed and sensitivity, the olfactory organ of insects provides a unique opportunity for detection. Insect antennae have been used in the past to detect not only sex pheromones but also chemicals that are relevant to humans, e.g., volatile compounds emanating from cancer cells or toxic and illicit substances. We describe here a protocol for using insect antennae on autonomous robots and present a proof of concept for tracking odor plumes to their source. The global response of olfactory neurons is recorded in situ in the form of electroantennograms (EAGs). Our experimental design, based on a whole insect preparation, allows stable recordings within a working day. In comparison, EAGs on excised antennae have a lifetime of 2 hr. A custom hardware/software interface was developed between the EAG electrodes and a robot. The measurement system resolves individual odor patches up to 10 Hz, which exceeds the time scale of artificial chemical sensors. The efficiency of EAG sensors for olfactory searches is further demonstrated in driving the robot toward a source of pheromone. By using identical olfactory stimuli and sensors as in real animals, our robotic platform provides a direct means for testing biological hypotheses about olfactory coding and search strategies. It may also prove beneficial for detecting other odorants of interests by combining EAGs from different insect species in a bioelectronic nose configuration or using nanostructured gas sensors that mimic insect antennae.

  5. Matching-to-Sample and Stimulus-Pairing-Observation Procedures in Stimulus Equivalence: The Effects of Number of Trials and Stimulus Arrangement

    ERIC Educational Resources Information Center

    Kinloch, Jennifer May; McEwan, James Stewart Anderson; Foster, T. Mary

    2013-01-01

    Studies comparing the effectiveness of the stimulus-pairing-observation and matching-to-sample procedures in facilitating equivalence relations have reported conflicting findings. This study compared the effectiveness of these procedures and examined the effect of stimulus arrangement and the number of training trials completed prior to each…

  6. Effects of olfactory sense on chocolate craving.

    PubMed

    Firmin, Michael W; Gillette, Aubrey L; Hobbs, Taylor E; Wu, Di

    2016-10-01

    In the present study, we assessed the effect of the olfactory sense on chocolate craving in college females. Building on previous research by Kemps and Tiggemann (2013), we hypothesized that a fresh scent would decrease one's craving level for chocolate food. While the precursor study only addressed the decrease of chocolate craving, we also hypothesized that a sweet scent would increase one's craving level for chocolate foods. In the present experiment, participants rated their craving levels after viewing images of chocolate foods and inhaling essential oils: one fresh (Slique™ essence), and one sweet (vanilla). Results supported both of the hypotheses: inhaling a fresh scent reduced females' craving levels; similarly, when a sweet scent was inhaled, the participants' craving levels for chocolate food increased. These findings are particularly beneficial for women seeking weight loss and the findings can be applied in contexts such as weight loss programs, therapy, and maintenance programs, even beyond college settings. The results are particularly useful for helping women regarding stimuli that might serve as triggers for chocolate cravings.

  7. Olfactory Neuroblastomas: An Experience of 24 Years

    PubMed Central

    Tural, Deniz; Yildiz, Ozcan; Selcukbiricik, Fatih; Ozturk, Mehmet Akif; Keles, Yildiz; Oz, Buge; Uzel, Omer; Demir, Gokhan; Mandel, Nil Molinas

    2011-01-01

    Objective. The aim of this study was to evaluate clinicopathological findings and the efficacy of the treatment modalities used in patients with olfactory neuroblastomas. Study Design. Retrospective record review. Setting. Istanbul University, Cerrahpasa Medical Faculty, medical oncology outpatient clinic. Subjects and Methods. There were 3 stage A tumors, 5 stage B and 11 stage C according to the Kadish staging system. There were 5 grade I/II and 12 grade III/IV according to the Hyams' histopathologic system. Involvement to orbita was detected in eight patients at the time of diagnosis. Results. The median follow-up period was 23.7 months. The 5-year survival rate for the whole group was 26%. The stage A/B groups exhibited a better survival rate than the C group with 2-year survival rates being 25 versus 71% respectively (P = .008). The grade I/II groups exhibited a better survival rate than the grade III/IV groups with 2-year survival rates being 50 versus 16% respectively (P = .001). The group who had orbital involvement exhibited a poor survival rate than the group of patients who had no involvement of the orbital. Conclusion. In our study, tumor stage, histopathologic grading, involvement of the orbita, brain and bone marow metastases were the statistically significant prognostic factors. PMID:22084732

  8. Phosphorylation of native porcine olfactory binding proteins.

    PubMed

    Nagnan-Le Meillour, Patricia; Le Danvic, Chrystelle; Brimau, Fanny; Chemineau, Philippe; Michalski, Jean-Claude

    2009-07-01

    The identification of various isoforms of olfactory binding proteins is of major importance to elucidate their involvement in detection of pheromones and other odors. Here, we report the characterization of the phosphorylation of OBP (odorant binding protein) and Von Ebner's gland protein (VEG) from the pig, Sus scrofa. After labeling with specific antibodies raised against the three types of phosphorylation (Ser, Thr, Tyr), the phosphate-modified residues were mapped by using the beta-elimination followed by Michael addition of dithiothreitol (BEMAD) method. Eleven phosphorylation sites were localized in the pOBP sequence and nine sites in the VEG sequence. OBPs are secreted by Bowman's gland cells in the extracellular mucus lining the nasal cavity. After tracking the secretion pathway in the rough endoplasmic reticulum of these cells, we hypothesize that these proteins may be phosphorylated by ectokinases that remain to be characterized. The existence of such a regulatory mechanism theoretically increases the number of OBP variants, and it suggests a more specific role for OBPs in odorant coding than the one of odorant solubilizer and transporter.

  9. Active forgetting of olfactory memories in Drosophila.

    PubMed

    Berry, Jacob A; Davis, Ronald L

    2014-01-01

    Failure to remember, or forgetting, is a phenomenon familiar to everyone and despite more than a century of scientific inquiry, why we forget what we once knew remains unclear. If the brain marshals significant resources to form and store memories, why is it that these memories become lost? In the last century, psychological studies have divided forgetting into decay theory, in which memory simply dissipates with time, and interference theory, in which additional learning or mental activity hinders memory by reducing its stability or retrieval (for review, Dewar et al., 2007; Wixted, 2004). Importantly, these psychological models of forgetting posit that forgetting is a passive property of the brain and thus a failure of the brain to retain memories. However, recent neuroscience research on olfactory memory in Drosophila has offered evidence for an alternative conclusion that forgetting is an "active" process, with specific, biologically regulated mechanisms that remove existing memories (Berry et al., 2012; Shuai et al., 2010). Similar to the bidirectional regulation of cell number by mitosis and apoptosis, protein concentration by translation and lysosomal or proteomal degradation, and protein phosphate modification by kinases and phosphatases, biologically regulated memory formation and removal would be yet another example in biological systems where distinct and separate pathways regulate the creation and destruction of biological substrates.

  10. Farnesol-Detecting Olfactory Neurons in Drosophila

    PubMed Central

    Ronderos, David S.; Lin, Chun-Chieh; Potter, Christopher J.

    2014-01-01

    We set out to deorphanize a subset of putative Drosophila odorant receptors expressed in trichoid sensilla using a transgenic in vivo misexpression approach. We identified farnesol as a potent and specific activator for the orphan odorant receptor Or83c. Farnesol is an intermediate in juvenile hormone biosynthesis, but is also produced by ripe citrus fruit peels. Here, we show that farnesol stimulates robust activation of Or83c-expressing olfactory neurons, even at high dilutions. The CD36 homolog Snmp1 is required for normal farnesol response kinetics. The neurons expressing Or83c are found in a subset of poorly characterized intermediate sensilla. We show that these neurons mediate attraction behavior to low concentrations of farnesol and that Or83c receptor mutants are defective for this behavior. Or83c neurons innervate the DC3 glomerulus in the antennal lobe and projection neurons relaying information from this glomerulus to higher brain centers target a region of the lateral horn previously implicated in pheromone perception. Our findings identify a sensitive, narrowly tuned receptor that mediates attraction behavior to farnesol and demonstrates an effective approach to deorphanizing odorant receptors expressed in neurons located in intermediate and trichoid sensilla that may not function in the classical “empty basiconic neuron” system. PMID:24623773

  11. OLFACTORY RESPONSES OF BLOWFLIES TO ALIPHATIC ALDEHYDES

    PubMed Central

    Dethier, V. G.

    1954-01-01

    The response of the blowfly Phormia regina to stimulation by aldehydes in the vapor phase has been studied by means of a specially designed olfactometer. The median rejection threshold and the maximum acceptance threshold were selected as criteria of response. For both acceptance and rejection the distribution of thresholds in the population is normal with respect to the logarithm of concentration. When thresholds are expressed as molar concentrations, the values decrease progressively as chain length is increased. There is no attraction beyond decanal and no rejection beyond dodecanal. When thresholds are expressed as activities, most members of the aldehyde series are approximately equally stimulating at rejection and equally stimulating at acceptance. The relationship is most exact over the middle range of chain lengths. There is a tendency for the terminal members to stimulate at higher activities. These relationships are in close agreement with those which were found earlier to apply to the normal aliphatic alcohols. The similarity between the relative actions of the members of the two series suggests that the relation of equal olfactory stimulation at equal thermodynamic activities by homologous aliphatic compounds at least for homologues of intermediate chain length may be of rather general application in olfaction. PMID:13174780

  12. Exploiting interspecific olfactory communication to monitor predators.

    PubMed

    Garvey, Patrick M; Glen, Alistair S; Clout, Mick N; Wyse, Sarah V; Nichols, Margaret; Pech, Roger P

    2017-03-01

    Olfaction is the primary sense of many mammals and subordinate predators use this sense to detect dominant species, thereby reducing the risk of an encounter and facilitating coexistence. Chemical signals can act as repellents or attractants and may therefore have applications for wildlife management. We devised a field experiment to investigate whether dominant predator (ferret Mustela furo) body odor would alter the behavior of three common mesopredators: stoats (Mustela erminea), hedgehogs (Erinaceus europaeus), and ship rats (Rattus rattus). We predicted that apex predator odor would lead to increased detections, and our results support this hypothesis as predator kairomones (interspecific olfactory messages that benefit the receiver) provoked "eavesdropping" behavior by mesopredators. Stoats exhibited the most pronounced responses, with kairomones significantly increasing the number of observations and the time spent at a site, so that their occupancy estimates changed from rare to widespread. Behavioral responses to predator odors can therefore be exploited for conservation and this avenue of research has not yet been extensively explored. A long-life lure derived from apex predator kairomones could have practical value, especially when there are plentiful resources that reduce the efficiency of food-based lures. Our results have application for pest management in New Zealand and the technique of using kairomones to monitor predators could have applications for conservation efforts worldwide.

  13. Olfactory assessment using the NIH Toolbox

    PubMed Central

    Doty, Richard L.; Murphy, Claire; Frank, Robert; Hoffman, Howard J.; Maute, Christopher; Kallen, Michael A.; Slotkin, Jerry

    2013-01-01

    The human olfactory system provides us with information about our environment that is critical to our physical and psychological well-being. Individuals can vary widely in their ability to detect, recognize, and identify odors, but still be within the range of normal function. Although several standardized tests of odor identification are available, few specifically address the issues in testing very young children, most of whom are likely to be unfamiliar with many of the odor stimuli used in adult tests and have limited ability to read and identify labels to select among choices. Based on the format of the San Diego Odor Identification Test and the delivery system of the University of Pennsylvania Smell Identification Test, we developed 2 versions of an odor identification test using standardized odor stimuli in a scratch-and-sniff format in which participants match 5 (children) or 9 (adults) odors to pictures representing the odor source. Results from normative testing and validation showed that for most participants, the test could be completed in 5 minutes or less and that the poorer performance among the youngest children and the elderly was consistent with data from tests with larger numbers of items. Expanding on the pediatric version of the test with adult-specific and public health–relevant odors increased the ecological validity of the test and facilitated comparisons of intraindividual performance across developmental stages. PMID:23479541

  14. Learning the way to blood: first evidence of dual olfactory conditioning in a blood-sucking insect, Rhodnius prolixus. I. Appetitive learning.

    PubMed

    Vinauger, Clément; Buratti, Laura; Lazzari, Claudio R

    2011-09-15

    It has been largely assumed that the individual experience of insects that are disease vectors might not only contribute to animal fitness, but also have an important influence on parasite transmission. Nevertheless, despite the invested efforts in testing the capacity to learn and remember information in blood-sucking insects, only little conclusive information has been obtained to date. Adapting a classical conditioning approach to our haematophagous model, we trained larvae of Rhodnius prolixus to associate L-lactic-acid, an odour perceived by these bugs but behaviourally neutral when presented alone, with food (i.e. positive reinforcement). Naive bugs--those exposed either to a conditioned stimulus (CS, L-lactic acid), unconditioned stimulus (US, heat) and reward (blood) alone or CS, US and reward in the absence of contingency--remained indifferent to the presence of an air stream loaded with L-lactic acid when tested in an olfactometer (random orientation), whereas the groups previously exposed to the contingency CS-US-reward (blood) were significantly attracted by L-lactic-acid. In a companion paper, the opposite, i.e. repellence, was induced in bugs exposed to the contingency of the same odour with a negative reinforcement. This constitutes the first evidence of olfactory conditioning in triatomine bugs, vectors of Chagas disease, and one of the few substantiations available to date of olfactory conditioning in haematophagous insects.

  15. Decoding Subjective Intensity of Nociceptive Pain from Pre-stimulus and Post-stimulus Brain Activities

    PubMed Central

    Tu, Yiheng; Tan, Ao; Bai, Yanru; Hung, Yeung Sam; Zhang, Zhiguo

    2016-01-01

    Pain is a highly subjective experience. Self-report is the gold standard for pain assessment in clinical practice, but it may not be available or reliable in some populations. Neuroimaging data, such as electroencephalography (EEG) and functional magnetic resonance imaging (fMRI), have the potential to be used to provide physiology-based and quantitative nociceptive pain assessment tools that complements self-report. However, existing neuroimaging-based nociceptive pain assessments only rely on the information in pain-evoked brain activities, but neglect the fact that the perceived intensity of pain is also encoded by ongoing brain activities prior to painful stimulation. Here, we proposed to use machine learning algorithms to decode pain intensity from both pre-stimulus ongoing and post-stimulus evoked brain activities. Neural features that were correlated with intensity of laser-evoked nociceptive pain were extracted from high-dimensional pre- and post-stimulus EEG and fMRI activities using partial least-squares regression (PLSR). Further, we used support vector machine (SVM) to predict the intensity of pain from pain-related time-frequency EEG patterns and BOLD-fMRI patterns. Results showed that combining predictive information in pre- and post-stimulus brain activities can achieve significantly better performance in classifying high-pain and low-pain and in predicting the rating of perceived pain than only using post-stimulus brain activities. Therefore, the proposed pain prediction method holds great potential in basic research and clinical applications. PMID:27148029

  16. Differential Contributions of Olfactory Receptor Neurons in a Drosophila Olfactory Circuit

    PubMed Central

    Newquist, Gunnar; Novenschi, Alexandra; Kohler, Donovan

    2016-01-01

    Abstract The ability of an animal to detect, discriminate, and respond to odors depends on the functions of its olfactory receptor neurons (ORNs). The extent to which each ORN, upon activation, contributes to chemotaxis is not well understood. We hypothesized that strong activation of each ORN elicits a different behavioral response in the Drosophila melanogaster larva by differentially affecting the composition of its navigational behavior. To test this hypothesis, we exposed Drosophila larvae to specific odorants to analyze the effect of individual ORN activity on chemotaxis. We used two different behavioral paradigms to analyze the chemotaxis response of larvae to odorants. When tested with five different odorants that elicit strong physiological responses from single ORNs, larval behavioral responses toward each odorant differed in the strength of attraction as well as in the composition of discrete navigational elements, such as runs and turns. Further, behavioral responses to odorants did not correlate with either the strength of odor gradients tested or the sensitivity of each ORN to its cognate odorant. Finally, we provide evidence that wild-type larvae with all ORNs intact exhibit higher behavioral variance than mutant larvae that have only a single pair of functional ORNs. We conclude that individual ORNs contribute differently to the olfactory circuit that instructs chemotactic responses. Our results, along with recent studies from other groups, suggest that ORNs are functionally nonequivalent units. These results have implications for understanding peripheral odor coding. PMID:27570823

  17. No evidence for visual context-dependency of olfactory learning in Drosophila

    NASA Astrophysics Data System (ADS)

    Yarali, Ayse; Mayerle, Moritz; Nawroth, Christian; Gerber, Bertram

    2008-08-01

    How is behaviour organised across sensory modalities? Specifically, we ask concerning the fruit fly Drosophila melanogaster how visual context affects olfactory learning and recall and whether information about visual context is getting integrated into olfactory memory. We find that changing visual context between training and test does not deteriorate olfactory memory scores, suggesting that these olfactory memories can drive behaviour despite a mismatch of visual context between training and test. Rather, both the establishment and the recall of olfactory memory are generally facilitated by light. In a follow-up experiment, we find no evidence for learning about combinations of odours and visual context as predictors for reinforcement even after explicit training in a so-called biconditional discrimination task. Thus, a ‘true’ interaction between visual and olfactory modalities is not evident; instead, light seems to influence olfactory learning and recall unspecifically, for example by altering motor activity, alertness or olfactory acuity.

  18. Properties and mechanisms of olfactory learning and memory.

    PubMed

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

    2014-01-01

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

  19. Olfactory Ionotropic Receptors in Mosquito Aedes albopictus (Diptera: Culicidae).

    PubMed

    Chen, Qian; Man, Yahui; Li, Jianyong; Pei, Di; Wu, Wenjian

    2017-03-28

    Ionotropic glutamate receptors (iGluRs) are a conserved family of ligand-gated ion channels that primarily function to mediate neuronal communication at synapses. A variant subfamily of iGluRs, the ionotropic receptors (IRs), was recently identified in insects and proved with the function in odorant recognition. Ionotropic receptors participate in a distinct olfactory signaling pathway that is independent of olfactory receptors activity. In the present study, we identify 102 putative IR genes, dubbed as AalbIr genes, in mosquito Aedes albopictus (Skuse) by in silico comparative sequence analysis. Among AalbIr genes, 19 show expression in the female antenna by RT-PCR. These putative olfactory AalbIRs share four conservative hydrophobic domains of amino acids, similar to the transmembrane and ion channel pore regions found in conventional iGluRs. To determine the potential function of these olfactory AalbIRs in host-seeking, we compared their transcript expression levels in the antennae of blood-fed females with that of non-blood-fed females by quantitative real-time RT-PCR. Three AalbIr genes showed downregulation when the mosquito finished a bloodmeal. These results may help to improve our understanding of the IR-mediated olfactory signaling in mosquitoes.

  20. Quantum Dot Distribution in the Olfactory Epithelium After Nasal Delivery

    NASA Astrophysics Data System (ADS)

    Garzotto, D.; De Marchis, S.

    2010-10-01

    Nanoparticles are used in a wide range of human applications from industrial to bio-medical fields. However, the unique characteristics of nanoparticles, such as the small size, large surface area per mass and high reactivity raises great concern on the adverse effects of these particles on ecological systems and human health. There are several pioneer studies reporting translocation of inhaled particulates to the brain through a potential neuronal uptake mediated by the olfactory nerve (1, 2, 3). However, no direct evidences have been presented up to now on the pathway followed by the nanoparticles from the nose to the brain. In addition to a neuronal pathway, nanoparticles could gain access to the central nervous system through extracellular pathways (perineuronal, perivascular and cerebrospinal fluid paths). In the present study we investigate the localization of intranasally delivered fluorescent nanoparticles in the olfactory epithelium. To this purpose we used quantum dots (QDs), a model of innovative fluorescent semiconductor nanocrystals commonly used in cell and animal biology (4). Intranasal treatments with QDs were performed acutely on adult CD1 mice. The olfactory epithelium was collected and analysed by confocal microscopy at different survival time after treatment. Data obtained indicate that the neuronal components of the olfactory epithelium are not preferentially involved in QDs uptake, thus suggesting nanoparticles can cross the olfactory epithelium through extracellular pathways.

  1. Evaluation of Olfactory and Gustatory Function of HIV Infected Women

    PubMed Central

    Kuti, Kehinde Mobolanle; Nwaorgu, Onyekwere George; Akinyinka, Olusina Olusegun

    2016-01-01

    Background. Compliance with medication requires good sense of smell and taste. Objective. To evaluate the olfactory and gustatory function of HIV infected women in Ibadan, Nigeria. Methods. A case control study of women comprising 83 HIV infected women and 79 HIV uninfected women. Subjective self-rating of taste and smell function was by visual analogue scale. Olfactory function was measured via olfactory threshold (OT), olfactory discrimination (OD), olfactory identification (OI), and TDI using “Sniffin' sticks” kits and taste function (Total Taste Strips (TTS) score) measurement was by taste strips. Results. The mean age of the HIV infected women was 43.67 years ± 10.72 and control was 41.48 years ± 10.99. There was no significant difference in the self-reported assessment of smell (p = 0.67) and taste (p = 0.84) of HIV infected and uninfected women. Although the mean OT, OD, OI, TDI, and TTS scores of HIV infected and uninfected women were within the normosmic and normogeusic values, the values were significantly higher in the controls (p < 0.05). Hyposmia was in 39.7% of subjects and 12.6% of controls while hypogeusia was in 15.7% of subjects and 1.3% of controls. Conclusions. Hyposmia and hypogeusia are commoner among the HIV infected women than the HIV uninfected women and the risk increases with an increased duration of highly active antiretroviral therapy. PMID:27047688

  2. Photoperiodic control of reproduction in olfactory-bulbectomized rats.

    PubMed

    Nelson, R J; Zucker, I

    1981-05-01

    30-day-old male rats were (1) sham-operated or subjected to (2) removal of the olfactory bulbs, (3) olfactory bulbectomy and blinding (4) olfactory bulbectomy and pinealectomy or (5) olfactory bulbectomy, blinding and pinealectomy. Animals were exposed from 30 to 110 days of age to long-day (14 h of light per day) or short-day (8 h of light per day) photoperiods. The reproductive system of neurologically-intact rats was not affected by exposure to short days. Nor did bulbectomy affect the reproductive system of rats exposed to long days. However, bulbectomized, short-day rats had significantly lower body weights, reduced testicular and seminal vesicle weights and lower plasma testosterone levels than did bulbectomized, long-day rats. The effects of short-day exposure on bulbectomized rats were prevented by pinealectomy. Short-day exposure and blinding exerted similar effects in bulbectomized rats. The testes of rats from all groups contained elongated spermatids; blinding and short-day treatment had no effect on spermatogenesis. Neither mating behavior nor the number of young sired was influenced by photoperiod in bulbectomized or intact rats. Removal of the olfactory bulbs unmasks photoperiodic responsiveness in rats; the antigonadal effects of short-day exposure are mediated by the pineal gland in bulbectomized rats as in species traditionally designated photoperiodic. The mechanisms by which bulbectomy renders rats responsive to short days are considered.

  3. Classical Olfactory Conditioning in the Oriental Fruit Fly, Bactrocera dorsalis

    PubMed Central

    Zeng, Xin Nian

    2015-01-01

    The oriental fruit fly, Bactrocera dorsalis, is a serious pest of fruits and vegetables. Methyl eugenol (ME), a male attractant, is used to against this fly by mass trapping. Control effect may be influenced by learning, which could modify the olfactory response of the fly to this attractant. To collect the behavioral evidence, studies on the capability of this fly for olfactory learning are necessary. We investigated olfactory learning in male flies with a classical olfactory conditioning procedure using restrained individuals under laboratory conditions. The acquisition of the proboscis extension reflex was used as the criterion for conditioning. A high conditioned response level was found in oriental fruit flies when an odor was presented in paired association with a sucrose reward but not when the odor and sucrose were presented unpaired. We also found that the conditioning performance was influenced by the odor concentration, intertrial interval, and starvation time. A slight sensitization elicited by imbibing sucrose was observed. These results indicate that oriental fruit flies have a high capacity to form an olfactory memory as a result of classical conditioning. PMID:25837420

  4. Environmental Toxicants-Induced Immune Responses in the Olfactory Mucosa

    PubMed Central

    Imamura, Fumiaki; Hasegawa-Ishii, Sanae

    2016-01-01

    Olfactory sensory neurons (OSNs) are the receptor cells for the sense of smell. Although cell bodies are located in the olfactory mucosa (OM) of the nasal cavity, OSN axons directly project to the olfactory bulb (OB) that is a component of the central nervous system (CNS). Because of this direct and short connection from this peripheral tissue to the CNS, the olfactory system has attracted attention as a port-of-entry for environmental toxicants that may cause neurological dysfunction. Selected viruses can enter the OB via the OM and directly affect the CNS. On the other hand, environmental toxicants may induce inflammatory responses in the OM, including infiltration of immune cells and production of inflammatory cytokines. In addition, these inflammatory responses cause the loss of OSNs that are then replaced with newly generated OSNs that re-connect to the OB after inflammation has subsided. It is now known that immune cells and cytokines in the OM play important roles in both degeneration and regeneration of OSNs. Thus, the olfactory system is a unique neuroimmune interface where interaction between nervous and immune systems in the periphery significantly affects the structure, neuronal circuitry, and immunological status of the CNS. The mechanisms by which immune cells regulate OSN loss and the generation of new OSNs are, however, largely unknown. To help develop a better understanding of the mechanisms involved, we have provided a review of key research that has investigated how the immune response in the OM affects the pathophysiology of OSNs. PMID:27867383

  5. Classical olfactory conditioning in the oriental fruit fly, Bactrocera dorsalis.

    PubMed

    Liu, Jia Li; Chen, Xiao Yan; Zeng, Xin Nian

    2015-01-01

    The oriental fruit fly, Bactrocera dorsalis, is a serious pest of fruits and vegetables. Methyl eugenol (ME), a male attractant, is used to against this fly by mass trapping. Control effect may be influenced by learning, which could modify the olfactory response of the fly to this attractant. To collect the behavioral evidence, studies on the capability of this fly for olfactory learning are necessary. We investigated olfactory learning in male flies with a classical olfactory conditioning procedure using restrained individuals under laboratory conditions. The acquisition of the proboscis extension reflex was used as the criterion for conditioning. A high conditioned response level was found in oriental fruit flies when an odor was presented in paired association with a sucrose reward but not when the odor and sucrose were presented unpaired. We also found that the conditioning performance was influenced by the odor concentration, intertrial interval, and starvation time. A slight sensitization elicited by imbibing sucrose was observed. These results indicate that oriental fruit flies have a high capacity to form an olfactory memory as a result of classical conditioning.

  6. Biomimetic chemical sensors using bioengineered olfactory and taste cells.

    PubMed

    Du, Liping; Zou, Ling; Zhao, Luhang; Wang, Ping; Wu, Chunsheng

    2014-01-01

    Biological olfactory and taste systems are natural chemical sensing systems with unique performances for the detection of environmental chemical signals. With the advances in olfactory and taste transduction mechanisms, biomimetic chemical sensors have achieved significant progress due to their promising prospects and potential applications. Biomimetic chemical sensors exploit the unique capability of biological functional components for chemical sensing, which are often sourced from sensing units of biological olfactory or taste systems at the tissue level, cellular level, or molecular level. Specifically, at the cellular level, there are mainly two categories of cells have been employed for the development of biomimetic chemical sensors, which are natural cells and bioengineered cells, respectively. Natural cells are directly isolated from biological olfactory and taste systems, which are convenient to achieve. However, natural cells often suffer from the undefined sensing properties and limited amount of identical cells. On the other hand, bioengineered cells have shown decisive advantages to be applied in the development of biomimetic chemical sensors due to the powerful biotechnology for the reconstruction of the cell sensing properties. Here, we briefly summarized the most recent advances of biomimetic chemical sensors using bioengineered olfactory and taste cells. The development challenges and future trends are discussed as well.

  7. Sad man's nose: Emotion induction and olfactory perception.

    PubMed

    Flohr, Elena L R; Erwin, Elena; Croy, Ilona; Hummel, Thomas

    2017-03-01

    Emotional and olfactory processing is frequently shown to be closely linked both anatomically and functionally. Depression, a disease closely related to the emotional state of sadness, has been shown to be associated with a decrease in olfactory sensitivity. The present study focuses on the state of sadness in n = 31 healthy subjects in order to investigate the specific contribution of this affective state in the modulation of olfactory processing. A sad or indifferent affective state was induced using 2 movies that were presented on 2 separate days. Afterward, chemosensory-evoked potentials were recorded after stimulation with an unpleasant (hydrogen sulfide: "rotten eggs") or a pleasant (phenyl ethyl alcohol: "rose") odorant. Latencies of N1 and P2 peaks were longer after induction of the sad affective state. Additionally, amplitudes were lower in a sad affective state when being stimulated with the unpleasant odorant. Processing of olfactory input has thus been reduced under conditions of the sad affective state. We argue that the affective state per se could at least partially account for the reduced olfactory sensitivity in depressed patients. To our knowledge, the present study is the first to show influence of affective state on chemosensory event-related potentials. (PsycINFO Database Record

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

    PubMed

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

    2011-10-19

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

  9. Bilateral Synchronous Ectopic Ethmoid Sinus Olfactory Neuroblastoma: A Case Report

    PubMed Central

    Leon-Soriano, Elena; Alfonso, Carolina; Yebenes, Laura; Garcia-Polo, Julio; Lassaletta, Luis; Gavilan, Javier

    2016-01-01

    Patient: Male, 41 Final Diagnosis: Olfactory neuroblastoma Symptoms: Left nasal obstruction • occasional left epistaxis • headache Medication: None Clinical Procedure: Nasal endoscopic examination • neck palpation • CT • bilateral endoscopic resection • MRI • PET-CT • postoperative radiotherapy Specialty: Otolaryngology Objective: Unusual clinical course Background: Olfactory neuroblastoma (ONB), also known as esthesioneuroblastoma, is a rare malignant head and neck cancer thought to originate from the olfactory epithelium. It typically invades contiguous structures at presentation. We report a very rare case of multifocal and ectopic ONB. Case Report: A 41-year-old man presented with left nasal obstruction and occasional left epistaxis associated with headache. Endoscopic examination of the nasal cavities and computed tomography suggested bilateral polypoid masses. Histopathological diagnosis after endoscopic resection established bilateral olfactory neuroblastoma of the ethmoid sinuses. The patient received postoperative radiotherapy. He remains free of disease 4 years after treatment. Conclusions: To the best of our knowledge this is the second documented case of multifocal ectopic olfactory neuroblastoma. Clinicians should consider ONB in the differential diagnosis of bilateral synchronous nasal and paranasal masses to avoid delayed diagnosis. Endoscopic resection of ONB could be an option in selected cases. PMID:27097989

  10. Biomimetic chemical sensors using bioengineered olfactory and taste cells

    PubMed Central

    Du, Liping; Zou, Ling; Zhao, Luhang; Wang, Ping; Wu, Chunsheng

    2014-01-01

    Biological olfactory and taste systems are natural chemical sensing systems with unique performances for the detection of environmental chemical signals. With the advances in olfactory and taste transduction mechanisms, biomimetic chemical sensors have achieved significant progress due to their promising prospects and potential applications. Biomimetic chemical sensors exploit the unique capability of biological functional components for chemical sensing, which are often sourced from sensing units of biological olfactory or taste systems at the tissue level, cellular level, or molecular level. Specifically, at the cellular level, there are mainly two categories of cells have been employed for the development of biomimetic chemical sensors, which are natural cells and bioengineered cells, respectively. Natural cells are directly isolated from biological olfactory and taste systems, which are convenient to achieve. However, natural cells often suffer from the undefined sensing properties and limited amount of identical cells. On the other hand, bioengineered cells have shown decisive advantages to be applied in the development of biomimetic chemical sensors due to the powerful biotechnology for the reconstruction of the cell sensing properties. Here, we briefly summarized the most recent advances of biomimetic chemical sensors using bioengineered olfactory and taste cells. The development challenges and future trends are discussed as well. PMID:25482234

  11. Circadian Regulation of Olfactory Receptor Neurons in the Cockroach Antenna

    PubMed Central

    Saifullah, A.S.M.; Page, Terry L.

    2013-01-01

    In the cockroach, olfactory sensitivity as measured by the amplitude of the electroantennogram (EAG) is regulated by the circadian system. We wished to determine how this rhythm in antennal response was reflected in the activity of individual olfactory receptor neurons. The amplitude of the electroantennogram (EAG) and the activity of olfactory receptor neurons (ORNs) in single olfactory sensilla were recorded simultaneously for 3–5 days in constant darkness from an antenna of the cockroach Leucophaea maderae. Both EAG amplitude and the spike frequency of the ORNs exhibited circadian rhythms with peak amplitude/activity occurring in the subjective day. The phases of the rhythms were dependent on the phase of the prior light cycle and thus were entrainable by light. Ablation of the optic lobes abolished the rhythm in EAG amplitude as has been previously reported. In contrast, the rhythm in ORN response persisted following surgery. These results indicated that a circadian clock outside the optic lobes can regulate the responses of olfactory receptor neurons and further that this modulation of the ORN response is not dependent on the circadian rhythm in EAG amplitude. PMID:19346451

  12. Elements of olfactory reception in adult Drosophila melanogaster.

    PubMed

    Martin, Fernando; Boto, Tamara; Gomez-Diaz, Carolina; Alcorta, Esther

    2013-09-01

    The olfactory system of Drosophila has become an attractive and simple model to investigate olfaction because it follows the same organizational principles of vertebrates, and the results can be directly applied to other insects with economic and sanitary relevance. Here, we review the structural elements of the Drosophila olfactory reception organs at the level of the cells and molecules involved. This article is intended to reflect the structural basis underlying the functional variability of the detection of an olfactory universe composed of thousands of odors. At the genetic level, we further detail the genes and transcription factors (TF) that determine the structural variability. The fly's olfactory receptor organs are the third antennal segments and the maxillary palps, which are covered with sensory hairs called sensilla. These sensilla house the odorant receptor neurons (ORNs) that express one or few odorant receptors in a stereotyped pattern regulated by combinations of TF. Also, perireceptor events, such as odor molecules transport to their receptors, are carried out by odorant binding proteins. In addition, the rapid odorant inactivation to preclude saturation of the system occurs by biotransformation and detoxification enzymes. These additional events take place in the lymph that surrounds the ORNs. We include some data on ionotropic and metabotropic olfactory transduction, although this issue is still under debate in Drosophila.

  13. A role for the anterior piriform cortex in early odor preference learning: evidence for multiple olfactory learning structures in the rat pup.

    PubMed

    Morrison, Gillian L; Fontaine, Christine J; Harley, Carolyn W; Yuan, Qi

    2013-07-01

    cFos activation in the anterior piriform cortex (aPC) occurs in early odor preference learning in rat pups (Roth and Sullivan 2005). Here we provide evidence that the pairing of odor as a conditioned stimulus and β-adrenergic activation in the aPC as an unconditioned stimulus generates early odor preference learning. β-Adrenergic blockade in the aPC prevents normal preference learning. Enhancement of aPC cAMP response element-binding protein (CREB) phosphorylation in trained hemispheres is consistent with a role for this cascade in early odor preference learning in the aPC. In vitro experiments suggested theta-burst-mediated long-term potentiation (LTP) at the lateral olfactory tract (LOT) to aPC synapse depends on N-methyl-D-aspartate (NMDA) receptors and can be significantly enhanced by β-adrenoceptor activation, which causes increased glutamate release from LOT synapses during LTP induction. NMDA receptors in aPC are also shown to be critical for the acquisition, but not expression, of odor preference learning, as would be predicted if they mediate initial β-adrenoceptor-promoted aPC plasticity. Ex vivo experiments 3 and 24 h after odor preference training reveal an enhanced LOT-aPC field excitatory postsynaptic potential (EPSP). At 3 h both presynaptic and postsynaptic potentiations support EPSP enhancement while at 24 h only postsynaptic potentiation is seen. LOT-LTP in aPC is excluded by odor preference training. Taken together with earlier work on the role of the olfactory bulb in early odor preference learning, these outcomes suggest early odor preference learning is normally supported by and requires multiple plastic changes at least at two levels of olfactory circuitry.

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

    PubMed

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

    2009-10-01

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

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

    PubMed

    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

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

    PubMed Central

    Schneider, Nanette Yvette

    2011-01-01

    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

  17. Novelty, stimulus control, and operant variability

    PubMed Central

    Shahan, Timothy A.; Chase, Philip N.

    2002-01-01

    Although behavior analysis has been criticized for failure to account for response novelty, many common behavior-analytic concepts and processes (e.g., selectionism, the operant, reinforcement, and stimulus control) assume variability both in the environment and in behavior. The importance of the relation between variability and novelty, particularly for verbal behavior, is discussed, and concepts used to account for novel behavior are examined. Experimental findings also are reviewed that suggest that variability in behavior can come under discriminative control, and these findings are applied to describe novel instances of behavior that may arise during problem solving. We conclude that variations provided and selected by the terms of the three-term contingency are powerful means for understanding novel behavior. PMID:22478385

  18. Hippocampal culture stimulus with 4-megahertz ultrasound

    NASA Astrophysics Data System (ADS)

    Muratore, Robert; LaManna, Justine K.; Lamprecht, Michael R.; Morrison, Barclay, III

    2012-10-01

    Among current modalities, ultrasound uniquely offers both millisecond and millimeter accuracy in noninvasively stimulating brain tissue. In addition, by sweeping the ultrasound beam within the refractory period of the neuronal tissue, ultrasonic neuromodulation can be adapted to target extended or multiply connected regions with quasi-simultaneity. Towards the development of this safe brain stimulus technique, the response of rat hippocampal cultures to ultrasound was investigated. Hippocampal slices, 0.4-mm thick, were obtained from 8-day old Sprague Dawley rats and cultured for 6 days. The in vitro cultures were exposed to multiple 100-ms 4.04-MHz ultrasound pulses from a 42-mm diameter, 90-mm spherical cap transducer. Peak pressure ranged from 0 through about 77 kPa. Responses in the form of electrical potentials from a sixty channel electrode array were digitized and recorded. The DG and CA1 regions of the hippocampus exhibited similar ultrasonically-evoked field potentials.

  19. Attention modulation of stimulus rivalry under swapping paradigm

    PubMed Central

    Doualot, Audrey; Simard, Mathieu; Saint-Amour, Dave

    2014-01-01

    Stimulus rivalry refers to the sustained periods of perceptual dominance that occur when different visual stimuli are swapped at a regular rate between eyes. This phenomenon is thought to involve mainly eye-independent mechanisms. Although several studies have reported that attention can increase image predominance in conventional binocular rivalry, it is unknown whether attention can specifically modulate stimulus rivalry. We addressed this question and manipulated the spatial characteristic of the stimuli to assess whether such an attention modulation could depend on visual processing hierarchy. The results showed that selective attention of stimulus rivalry significantly increased the predominance of the attended stimulus, regardless of the stimulus' spatial characteristics. No effect was observed on the swapping percept. The findings are discussed in the context of recent models attempting to characterize stimulus rivalry between eye-dependent and eye-independent levels. PMID:25469220

  20. Interventions for Stimulus Deprivation Amblyopia [Review

    PubMed Central

    Antonio-Santos, Aileen; Powell, Christine; Vedula, Satyanarayana S

    2014-01-01

    Background Stimulus deprivation amblyopia (SDA) develops due to an obstruction to the clear passage of light, preventing clear formation of an image on the retina for example, cataract, ptosis (droopy eyelid). It is particularly severe and can be resistant to treatment and the visual prognosis is often poor. Stimulus deprivation amblyopia is rare and precise estimates of prevalence difficult to come by; it probably constitutes less than 3% of all cases of amblyopia. In developed countries most patients present under the age of one; in less developed parts of the world presentation is likely to be significantly later than this. The mainstay of treatment is patching of the better-seeing eye but regimes vary, treatment is difficult to execute and results are often disappointing. Objectives The objectives of this review were to evaluate the effectiveness of occlusion treatment for SDA, determine the optimum treatment regime and factors that may affect outcome. Search strategy We searched the Cochrane Central Register of Controlled Trials - CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) on The Cochrane Library (2006, Issue 1), MEDLINE (1996 to April 2006), EMBASE (1980 to April 2006) and LILACS (Latin American and Caribbean Literature on Health Sciences) (to November 2004). There were no date or language restrictions. Selection criteria We aimed to include randomised and quasi-randomised controlled trials of subjects with unilateral SDA defined as worse than 0.2 LogMAR or equivalent. There were no restrictions with respect to age, gender, ethnicity, co-morbidities, medication use, and the number of participants. Data collection and analysis Two authors independently assessed study abstracts identified by the electronic searches. Main results No trials were identified that met the inclusion criteria. Authors' conclusions It is not possible to conclude how effective treatment for SDA is or which treatment regime produces the best results

  1. Deletion of Type 3 Adenylyl Cyclase Perturbs the Postnatal Maturation of Olfactory Sensory Neurons and Olfactory Cilium Ultrastructure in Mice

    PubMed Central

    Zhang, Zhe; Yang, Dong; Zhang, Mengdi; Zhu, Ning; Zhou, Yanfen; Storm, Daniel R.; Wang, Zhenshan

    2017-01-01

    Type 3 adenylyl cyclase (Adcy3) is localized to the cilia of olfactory sensory neurons (OSNs) and is an essential component of the olfactory cyclic adenosine monophosphate (cAMP) signaling pathway. Although the role of this enzyme in odor detection and axonal projection in OSNs was previously characterized, researchers will still have to determine its function in the maturation of postnatal OSNs and olfactory cilium ultrastructure. Previous studies on newborns showed that the anatomic structure of the main olfactory epithelium (MOE) of Adcy3 knockout mice (Adcy3-/-) is indistinguishable from that of their wild-type littermates (Adcy3+/+), whereas the architecture and associated composition of MOE are relatively underdeveloped at this early age. The full effects of sensory deprivation on OSNs may not also be exhibited in such age. In the present study, following a comparison of postnatal OSNs in seven-, 30-, and 90-day-old Adcy3-/- mice and wild-type controls (Adcy3+/+), we observed that the absence of Adcy3 leads to cumulative defects in the maturation of OSNs. Upon aging, Adcy3-/- OSNs exhibited increase in immature cells and reduction in mature cells along with elevated apoptosis levels. The density and ultrastructure of Adcy3-/- cilia were also disrupted in mice upon aging. Collectively, our results reveal an indispensable role of Adcy3 in postnatal maturation of OSNs and maintenance of olfactory cilium ultrastructure in mice through adulthood. PMID:28154525

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

    PubMed

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

    2013-12-04

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

  3. Behavioural responses to olfactory cues in carrion crows.

    PubMed

    Wascher, Claudia A F; Heiss, Rebecca S; Baglione, Vittorio; Canestrari, Daniela

    2015-02-01

    Until recently, the use of olfactory signals in birds has been largely ignored, despite the fact that birds do possess a fully functioning olfactory system and have been shown to use odours in social and foraging tasks, predator detection and orientation. The present study investigates whether carrion crows (Corvus corone corone), a bird species living in complex social societies, respond behaviourally to olfactory cues of conspecifics. During our experiment, carrion crows were observed less often close to the conspecific scent compared to a control side. Because conspecific scent was extracted during handling, a stressful procedure for birds, we interpreted the general avoidance of the 'scent' side as disfavour against a stressed conspecific. However, males, unlike females, showed less avoidance towards the scent of a familiar individual compared to an unfamiliar one, which might reflect a stronger interest in the information conveyed and/or willingness to provide social support.

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

    PubMed Central

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

    2015-01-01

    How the olfactory bulb organizes and processes odor inputs through fundamental operations of its microcircuits is largely unknown. To gain new insight we focus on odor-activated synaptic clusters related to individual glomeruli, which we call glomerular units. Using a 3D model of mitral and granule cell interactions supported by experimental findings, combined with a matrix-based representation of glomerular operations, we identify the mechanisms for forming one or more glomerular units in response to a given odor, how and to what extent the glomerular units interfere or interact with each other during learning, their computational role within the olfactory bulb microcircuit, and how their actions can be formalized into a theoretical framework in which the olfactory bulb can be considered to contain “odor operators” unique to each individual. The results provide new and specific theoretical and experimentally testable predictions. PMID:26100895

  5. Parallel and orthogonal stimulus in ultradiluted neural networks

    NASA Astrophysics Data System (ADS)

    Sobral, G. A., Jr.; Vieira, V. M.; Lyra, M. L.; da Silva, C. R.

    2006-10-01

    Extending a model due to Derrida, Gardner, and Zippelius, we have studied the recognition ability of an extreme and asymmetrically diluted version of the Hopfield model for associative memory by including the effect of a stimulus in the dynamics of the system. We obtain exact results for the dynamic evolution of the average network superposition. The stimulus field was considered as proportional to the overlapping of the state of the system with a particular stimulated pattern. Two situations were analyzed, namely, the external stimulus acting on the initialization pattern (parallel stimulus) and the external stimulus acting on a pattern orthogonal to the initialization one (orthogonal stimulus). In both cases, we obtained the complete phase diagram in the parameter space composed of the stimulus field, thermal noise, and network capacity. Our results show that the system improves its recognition ability for parallel stimulus. For orthogonal stimulus two recognition phases emerge with the system locking at the initialization or stimulated pattern. We confront our analytical results with numerical simulations for the noiseless case T=0 .

  6. Parallel and orthogonal stimulus in ultradiluted neural networks.

    PubMed

    Sobral, G A; Vieira, V M; Lyra, M L; da Silva, C R

    2006-10-01

    Extending a model due to Derrida, Gardner, and Zippelius, we have studied the recognition ability of an extreme and asymmetrically diluted version of the Hopfield model for associative memory by including the effect of a stimulus in the dynamics of the system. We obtain exact results for the dynamic evolution of the average network superposition. The stimulus field was considered as proportional to the overlapping of the state of the system with a particular stimulated pattern. Two situations were analyzed, namely, the external stimulus acting on the initialization pattern (parallel stimulus) and the external stimulus acting on a pattern orthogonal to the initialization one (orthogonal stimulus). In both cases, we obtained the complete phase diagram in the parameter space composed of the stimulus field, thermal noise, and network capacity. Our results show that the system improves its recognition ability for parallel stimulus. For orthogonal stimulus two recognition phases emerge with the system locking at the initialization or stimulated pattern. We confront our analytical results with numerical simulations for the noiseless case T = 0.

  7. Spatiotemporal Dynamics of Cortical Representations during and after Stimulus Presentation

    PubMed Central

    van de Nieuwenhuijzen, Marieke E.; van den Borne, Eva W. P.; Jensen, Ole; van Gerven, Marcel A. J.

    2016-01-01

    Visual perception is a spatiotemporally complex process. In this study, we investigated cortical dynamics during and after stimulus presentation. We observed that visual category information related to the difference between faces and objects became apparent in the occipital lobe after 63 ms. Within the next 110 ms, activation spread out to include the temporal lobe before returning to residing mainly in the occipital lobe again. After stimulus offset, a peak in information was observed, comparable to the peak after stimulus onset. Moreover, similar processes, albeit not identical, seemed to underlie both peaks. Information about the categorical identity of the stimulus remained present until 677 ms after stimulus offset, during which period the stimulus had to be retained in working memory. Activation patterns initially resembled those observed during stimulus presentation. After about 200 ms, however, this representation changed and class-specific activity became more equally distributed over the four lobes. These results show that, although there are common processes underlying stimulus representation both during and after stimulus presentation, these representations change depending on the specific stage of perception and maintenance. PMID:27242453

  8. Olfactory discrimination of structurally similar alcohols by cockroaches.

    PubMed

    Sakura, M; Okada, R; Mizunami, M

    2002-11-01

    The capability of the cockroach Periplaneta americana to discriminate odors of structurally similar aliphatic alcohols was studied by using an operant conditioning paradigm. Cockroaches were trained to discriminate three odors: one odor associated with sucrose solution (reward) and two odors associated with NaCl solution (non-reward). After training, their odor preferences were tested by counting the number of visits to each odor source. We tested the capability of cockroaches to discriminate (1) three normal aliphatic alcohols with different numbers of carbon (1-pentanol, 1-hexanol and 1-octanol), (2) three C6 aliphatic alcohols (1-hexanol, 2-hexanol and trans-2-hexen-1-ol), (3) binary mixtures of two of these three alcohols and their components, and (4) 1-hexanol solution of three different concentrations (1, 10 and 100 micro g micro l(-1)). Cockroaches exhibited higher preferences for the odors associated with reward in these tests, and we therefore conclude that cockroaches can discriminate these odors. However, discrimination of 1-hexanol and trans-2-hexen-1-ol and their binary mixture was imperfect, in that some statistical tests suggested significant level of discrimination but other tests did not. In addition, the cockroaches learned to associate a 1-hexanol solution of the highest or lowest concentration with sucrose reward but failed to learn to associate 1-hexanol of an intermediate concentration with reward.

  9. Appetitive associative olfactory learning in Drosophila larvae.

    PubMed

    Apostolopoulou, Anthi A; Widmann, Annekathrin; Rohwedder, Astrid; Pfitzenmaier, Johanna E; Thum, Andreas S

    2013-02-18

    In the following we describe the methodological details of appetitive associative olfactory learning in Drosophila larvae. The setup, in combination with genetic interference, provides a handle to analyze the neuronal and molecular fundamentals of specifically associative learning in a simple larval brain. Organisms can use past experience to adjust present behavior. Such acquisition of behavioral potential can be defined as learning, and the physical bases of these potentials as memory traces. Neuroscientists try to understand how these processes are organized in terms of molecular and neuronal changes in the brain by using a variety of methods in model organisms ranging from insects to vertebrates. For such endeavors it is helpful to use model systems that are simple and experimentally accessible. The Drosophila larva has turned out to satisfy these demands based on the availability of robust behavioral assays, the existence of a variety of transgenic techniques and the elementary organization of the nervous system comprising only about 10,000 neurons (albeit with some concessions: cognitive limitations, few behavioral options, and richness of experience questionable). Drosophila larvae can form associations between odors and appetitive gustatory reinforcement like sugar. In a standard assay, established in the lab of B. Gerber, animals receive a two-odor reciprocal training: A first group of larvae is exposed to an odor A together with a gustatory reinforcer (sugar reward) and is subsequently exposed to an odor B without reinforcement. Meanwhile a second group of larvae receives reciprocal training while experiencing odor A without reinforcement and subsequently being exposed to odor B with reinforcement (sugar reward). In the following both groups are tested for their preference between the two odors. Relatively higher preferences for the rewarded odor reflect associative learning--presented as a performance index (PI). The conclusion regarding the associative

  10. Array comparative genomic hybridization analysis of olfactory neuroblastoma.

    PubMed

    Guled, Mohamed; Myllykangas, Samuel; Frierson, Henry F; Mills, Stacey E; Knuutila, Sakari; Stelow, Edward B

    2008-06-01

    Olfactory neuroblastoma is an unusual neuroectodermal malignancy, which is thought to arise at the olfactory membrane of the sinonasal tract. Due to its rarity, little is understood regarding its molecular and cytogenetic abnormalities. The aim of the current study is to identify specific DNA copy number changes in olfactory neuroblastoma. Thirteen dissected tissue samples were analyzed using array comparative genomic hybridization. Our results show that gene copy number profiles of olfactory neuroblastoma samples are complex. The most frequent changes included gains at 7q11.22-q21.11, 9p13.3, 13q, 20p/q, and Xp/q, and losses at 2q31.1, 2q33.3, 2q37.1, 6q16.3, 6q21.33, 6q22.1, 22q11.23, 22q12.1, and Xp/q. Gains were more frequent than losses, and high-stage tumors showed more alterations than low-stage olfactory neuroblastoma. Frequent changes in high-stage tumors were gains at 13q14.2-q14.3, 13q31.1, and 20q11.21-q11.23, and loss of Xp21.1 (in 66% of cases). Gains at 5q35, 13q, and 20q, and losses at 2q31.1, 2q33.3, and 6q16-q22, were present in 50% of cases. The identified regions of gene copy number change have been implicated in a variety of tumors, especially carcinomas. In addition, our results indicate that gains in 20q and 13q may be important in the progression of this cancer, and that these regions possibly harbor genes with functional relevance in olfactory neuroblastoma.

  11. Functional MRI of the Olfactory System in Conscious Dogs

    PubMed Central

    Jia, Hao; Pustovyy, Oleg M.; Waggoner, Paul; Beyers, Ronald J.; Schumacher, John; Wildey, Chester; Barrett, Jay; Morrison, Edward; Salibi, Nouha; Denney, Thomas S.; Vodyanoy, Vitaly J.; Deshpande, Gopikrishna

    2014-01-01

    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. PMID:24466054

  12. Phylogenic Studies on the Olfactory System in Vertebrates

    PubMed Central

    TANIGUCHI, Kazuyuki; TANIGUCHI, Kazumi

    2014-01-01

    ABSTRACT 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

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

    PubMed Central

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

    2016-01-01

    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

  14. Zebrafish olfactory receptor ORA1 recognizes a putative reproductive pheromone

    PubMed Central

    Ahuja, Gaurav; Korsching, Sigrun

    2014-01-01

    Teleost v1r-related ora genes constitute a small and highly conserved olfactory receptor gene family, and their direct orthologs are present in lineages as distant as cartilaginous fishes. Recently, the first member of the ora gene family was deorphanized. ORA1 detects p-hydroxyphenylacetic acid with high sensitivity and specificity. This compound elicits olfactory-mediated oviposition behavior in adult zebrafish mating pairs, suggesting a potential function as a reproductive pheromone for pHPAA itself or a related substance. This association of an odor and its cognate receptor with an oviposition response may provide a molecular basis for studying neural circuits involved in fish reproduction. PMID:26842458

  15. Noradrenergic and cholinergic modulation of olfactory bulb sensory processing

    PubMed Central

    Devore, Sasha; Linster, Christiane

    2012-01-01

    Neuromodulation in sensory perception serves important functions such as regulation of signal to noise ratio, attention, and modulation of learning and memory. Neuromodulators in specific sensory areas often have highly similar cellular, but distinct behavioral effects. To address this issue, we here review the function and role of two neuromodulators, acetylcholine (Ach) and noradrenaline (NE) for olfactory sensory processing in the adult main olfactory bulb. We first describe specific bulbar sensory computations, review cellular effects of each modulator and then address their specific roles in bulbar sensory processing. We finally put these data in a behavioral and computational perspective. PMID:22905025

  16. Cortical Plasticity and Olfactory Function in Early Blindness.

    PubMed

    Araneda, Rodrigo; Renier, Laurent A; Rombaux, Philippe; Cuevas, Isabel; De Volder, Anne G

    2016-01-01

    Over the last decade, functional brain imaging has provided insight to the maturation processes and has helped elucidate the pathophysiological mechanisms involved in brain plasticity in the absence of vision. In case of congenital blindness, drastic changes occur within the deafferented "visual" cortex that starts receiving and processing non visual inputs, including olfactory stimuli. This functional reorganization of the occipital cortex gives rise to compensatory perceptual and cognitive mechanisms that help blind persons achieve perceptual tasks, leading to superior olfactory abilities in these subjects. This view receives support from psychophysical testing, volumetric measurements and functional brain imaging studies in humans, which are presented here.

  17. Cortical Plasticity and Olfactory Function in Early Blindness

    PubMed Central

    Araneda, Rodrigo; Renier, Laurent A.; Rombaux, Philippe; Cuevas, Isabel; De Volder, Anne G.

    2016-01-01

    Over the last decade, functional brain imaging has provided insight to the maturation processes and has helped elucidate the pathophysiological mechanisms involved in brain plasticity in the absence of vision. In case of congenital blindness, drastic changes occur within the deafferented “visual” cortex that starts receiving and processing non visual inputs, including olfactory stimuli. This functional reorganization of the occipital cortex gives rise to compensatory perceptual and cognitive mechanisms that help blind persons achieve perceptual tasks, leading to superior olfactory abilities in these subjects. This view receives support from psychophysical testing, volumetric measurements and functional brain imaging studies in humans, which are presented here. PMID:27625596

  18. Functional Specialization of Olfactory Glomeruli in a Moth

    NASA Astrophysics Data System (ADS)

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

    1992-05-01

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

  19. In vivo vomeronasal stimulation reveals sensory encoding of conspecific and allospecific cues by the mouse accessory olfactory bulb

    PubMed Central

    Ben-Shaul, Y.; Katz, L. C.; Mooney, R.; Dulac, C.

    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 to the experimental difficulty of precise stimulus delivery to the VNO. To determine the basic rules of information processing in the vomeronasal system, we developed a unique preparation that allows controlled and repeated stimulus delivery to the VNO and combined this approach with multisite recordings of neuronal activity in the AOB. We found that urine, a well-characterized pheromone source in mammals, as well as saliva, activates AOB neurons in a manner that reliably encodes the donor animal’s sexual and genetic status. We also identified a significant fraction of AOB neurons that respond robustly and selectively to predator cues, suggesting an expanded role for the vomeronasal system in both conspecific and interspecific recognition. Further analysis reveals that mixed stimuli from distinct sources evoke synergistic responses in AOB neurons, thereby supporting the notion of integrative processing of chemosensory information. PMID:20194746

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

    PubMed

    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.

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

    PubMed

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

    2013-12-01

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

  2. Gamma Knife radiosurgery of olfactory groove meningiomas provides a method to preserve subjective olfactory function.

    PubMed

    Gande, Abhiram; Kano, Hideyuki; Bowden, Gregory; Mousavi, Seyed H; Niranjan, Ajay; Flickinger, John C; Lunsford, L Dade

    2014-02-01

    Anosmia is a common outcome after resection of olfactory groove meningioma(s) (OGM) and for some patients represents a significant disability. To evaluate long term tumor control rates and preservation of subjective olfaction after Gamma Knife (GK) stereotactic radiosurgery (SRS) of OGM. We performed a retrospective chart review and telephone assessments of 41 patients who underwent GK SRS between 1987 and 2008. Clinical outcomes were stratified by full, partial or no subjective olfaction, whereas tumor control was assessed by changes in volume greater or lesser than 25%. The median clinical and imaging follow-up were 76 and 65 months, respectively. Prior to SRS, 19 (46%) patients had surgical resections and two (5%) had received fractionated radiation therapy. Twenty four patients (59%) reported a normal sense of smell, 12 (29%) reported a reduced sense of smell and five (12%) had complete anosmia. The median tumor volume was 8.5 cm(3) (range 0.6-56.1), the mean radiation dose at the tumor margin was 13 Gy (range 10-20) and the median estimated dose to the olfactory nerve was 5.1 Gy (range 1.1-18.1). At follow-up, 27 patients (66%) reported intact olfaction (three (7%) described return to a normal sense of smell), nine (22%) described partial anosmia, and five (12%) had complete anosmia. No patient reported deterioration in olfaction after SRS. Thirteen patients (32%) showed significant tumor regression, 26 (63%) had no further growth and two (5%) had progressed. The progression free tumor control rates were 97% at 1 year and 95% at 2, 10 and 20 years. Symptomatic adverse radiation effects occurred in three (7%) patients. Stereotactic radiosurgery provided both long term tumor control and preservation of olfaction.

  3. Effect of the antiepileptic therapy on olfactory disorders associated with mesial temporal sclerosis.

    PubMed

    Caminiti, Fabrizia; De Salvo, Simona; Nunnari, Domenica; Bramanti, Placido; Ciurleo, Rosella; Granata, Francesca; Marino, Silvia

    2016-08-01

    Parosmia has been described in neurological disorders, including temporal epilepsy. We reported a case of parosmia associated with unilateral hyposmia and mesial temporal sclerosis. We assessed the olfactory function by using Sniffin' sticks test and olfactory event-related potentials (OERPs). The findings of unilateral deficit of identification associated with parosmia only in the side ipsilateral to mesial temporal sclerosis area, that involves temporal olfactory regions responsible for higher level of smell processing, suggest a central genesis of olfactory disorders. The administration of levetiracetam restored olfactory function, OERP N1-P2 amplitude, and mesial temporal sclerosis-related electroencephalographic findings.

  4. Motormouth: Mere Exposure Depends on Stimulus-Specific Motor Simulations

    ERIC Educational Resources Information Center

    Topolinski, Sascha; Strack, Fritz

    2009-01-01

    The authors apply an embodied account to mere exposure, arguing that through the repeated exposure of a particular stimulus, motor responses specifically associated to that stimulus are repeatedly simulated, thus trained, and become increasingly fluent. This increased fluency drives preferences for repeated stimuli. This hypothesis was tested by…

  5. A Computer Tutorial on the Principles of Stimulus Generalization.

    ERIC Educational Resources Information Center

    Graham, Robert B.

    1998-01-01

    Describes a computer tutorial that teaches the fundamentals of stimulus generalization in operant learning. Concepts covered include reinforcement, discrimination learning, stimulus continua, generalization, generalization gradients, and peak shift. The tutorial also reviews applications in human and animal situations. The content is appropriate…

  6. Deprivation in American Affluence: The Theory of Stimulus Addiction.

    ERIC Educational Resources Information Center

    Machell, David F.

    1991-01-01

    Discusses theory of stimulus addiction, a process of human accommodation to stimuli which fosters dependency and may foster addiction. Suggests that a society of affluence may be prone to addictiveness because the more continuous the stimuli the person experiences, the more tolerance is created, and with tolerance comes stimulus deprivation.…

  7. Asynchronous stimulus presentation in visual extinction: a psychophysical study.

    PubMed

    Geeraerts, Sarah; Lafosse, Christophe; Vandenbussche, Erik; Verfaillie, Karl

    2010-09-01

    Patients showing visual extinction as a consequence of a unilateral brain lesion can correctly detect a single stimulus in either hemifield but fail to detect the contralesional stimulus (or at least process the stimulus less efficiently) when it is presented simultaneously with an ipsilesional stimulus. In an attempt to uncover the nature of the underlying deficit, some studies have manipulated the temporal characteristics of stimulus presentation. Contra- and ipsilesional stimuli with different stimulus onset asynchronies are typically used. In the present study, visual extinction was investigated in a group of left neglect patients (N=10) using a psychophysical paradigm with different stimulus onset asynchronies of target and distractor stimuli presented in different hemifields. Contrast thresholds for a target grating were determined with the target either in isolation or in the presence of an irrelevant distractor grating. When target and distractor gratings were presented simultaneously, neglect patients showed a significant extinction effect, i.e., a significant interference from the right hemifield distractor with left hemifield contrast sensitivity. When the right hemifield distractor preceded the left hemifield target stimulus by 250 ms, two different patterns of results were observed in the neglect patients. Five patients showed a significant improvement compared to the simultaneous presentation condition, five other patients showed a significant increase of the extinction effect. The results suggest that different underlying mechanisms, maybe due to different lesion locations, can cause extinction in neglect patients.

  8. Stimulus Variability and Perceptual Learning of Nonnative Vowel Categories

    ERIC Educational Resources Information Center

    Brosseau-Lapre, Francoise; Rvachew, Susan; Clayards, Meghan; Dickson, Daniel

    2013-01-01

    English-speakers' learning of a French vowel contrast (/schwa/-/slashed o/) was examined under six different stimulus conditions in which contrastive and noncontrastive stimulus dimensions were varied orthogonally to each other. The distribution of contrastive cues was varied across training conditions to create single prototype, variable far…

  9. Mechanics of Coriolis stimulus and inducing factors of motion sickness.

    PubMed

    Isu, N; Shimizu, T; Sugata, K

    2001-12-01

    To specify inducing factors of motion sickness comprised in Coriolis stimulus, or cross-coupled rotation, the sensation of rotation derived from the semicircular canal system during and after Coriolis stimulus under a variety of stimulus conditions, was estimated by an approach from mechanics with giving minimal hypotheses and simplifications on the semicircular canal system and the sensory nervous system. By solving an equation of motion of the endolymph during Coriolis stimulus, rotating angle of the endolymph was obtained, and the sensation of rotation derived from each semicircular canal was estimated. Then the sensation derived from the whole semicircular canal system was particularly considered in two cases of a single Coriolis stimulus and cyclic Coriolis stimuli. The magnitude and the direction of sensation of rotation were shown to depend on an angular velocity of body rotation and a rotating angle of head movement (amplitude of head oscillation when cyclic Coriolis stimuli) irrespective of initial angle (center angle) of the head relative to the vertical axis. The present mechanical analysis of Coriolis stimulus led a suggestion that the severity of nausea evoked by Coriolis stimulus is proportional to the effective value of the sensation of rotation caused by the Coriolis stimulus.

  10. Drosophila Learn Opposing Components of a Compound Food Stimulus

    PubMed Central

    Das, Gaurav; Klappenbach, Martín; Vrontou, Eleftheria; Perisse, Emmanuel; Clark, Christopher M.; Burke, Christopher J.; Waddell, Scott

    2014-01-01

    Summary Dopaminergic neurons provide value signals in mammals and insects [1–3]. During Drosophila olfactory learning, distinct subsets of dopaminergic neurons appear to assign either positive or negative value to odor representations in mushroom body neurons [4–9]. However, it is not known how flies evaluate substances that have mixed valence. Here we show that flies form short-lived aversive olfactory memories when trained with odors and sugars that are contaminated with the common insect repellent DEET. This DEET-aversive learning required the MB-MP1 dopaminergic neurons that are also required for shock learning [7]. Moreover, differential conditioning with DEET versus shock suggests that formation of these distinct aversive olfactory memories relies on a common negatively reinforcing dopaminergic mechanism. Surprisingly, as time passed after training, the behavior of DEET-sugar-trained flies reversed from conditioned odor avoidance into odor approach. In addition, flies that were compromised for reward learning exhibited a more robust and longer-lived aversive-DEET memory. These data demonstrate that flies independently process the DEET and sugar components to form parallel aversive and appetitive olfactory memories, with distinct kinetics, that compete to guide learned behavior. PMID:25042590

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

    PubMed

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

    2015-04-01

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

  12. Regulatory Fit Effects on Stimulus Identification

    PubMed Central

    Glass, Brian D.; Maddox, W. Todd; Markmana, Arthur B.

    2010-01-01

    This article examines the effects of a fit between a person's global regulatory focus and the local task reward structure on perceptual processing and judgment. On each trial, participants were presented with one of two briefly presented stimuli and were asked to identify it. Participants were placed in a promotion focus (a situationally induced sensitivity to gains) or a prevention focus (a situationally induced sensitivity to losses) and were asked to maximize gains or minimize losses. An asymmetric payoff ratio biased the overall reward toward one identification response over the other. Two experiments tested the role of regulatory fit when internal familiarity and perceptual sensitivity was low or high. When familiarity and sensitivity were low, participants in a regulatory fit (promotion focus with gains or a prevention focus with losses) showed greater perceptual sensitivity, but no response bias differences relative to participants in a regulatory mismatch. When familiarity and sensitivity were high, participants in a regulatory fit showed a response bias toward the high payoff stimulus, but no differences in perceptual sensitivity. Speculation on the neurobiological basis of this effect, as well as implications of this work for clinical disorders, such as depression, is offered. PMID:21264696

  13. The interoceptive Pavlovian stimulus effects of caffeine.

    PubMed

    Murray, Jennifer E; Li, Chia; Palmatier, Matthew I; Bevins, Rick A

    2007-04-01

    The present research sought to test whether caffeine functioned as a Pavlovian cue in two ways--as a positive drug feature or as a conditional stimulus (CS). As a positive feature (Experiment 1), brief light presentations were followed by sucrose only on sessions in which caffeine (10 mg/kg) was administered. On intermixed saline sessions, light presentations were not followed by sucrose. The light came to control robust goal tracking (i.e., conditioned responding) only in caffeine sessions. Thus, caffeine disambiguates when the light was paired with sucrose. Decreasing the dose of caffeine decreased the conditioned responding evoked by the light (ED(50)=4.16 mg/kg). Neither nicotine nor amphetamine substituted for the caffeine feature. As a CS, caffeine (10 or 30 mg/kg, Experiments 2a and 2b, respectively) signaled intermittent access to sucrose--no light presentations. No sucrose or lights were presented on intermixed saline sessions. The caffeine CS, regardless of training dose, acquired the ability to evoke only a weak goal-tracking CR. The nature of this dissociation between caffeine as a drug feature and a CS is discussed within the context of past research finding a similar dissociation with amphetamine and chlordiazepoxide, but not with nicotine.

  14. Transformations of mathematical and stimulus functions.

    PubMed

    Ninness, Chris; Barnes-Holmes, Dermot; Rumph, Robin; McCuller, Glen; Ford, Angela M; Payne, Robert; Ninness, Sharon K; Smith, Ronald J; Ward, Todd A; Elliott, Marc P

    2006-01-01

    Following a pretest, 8 participants who were unfamiliar with algebraic and trigonometric functions received a brief presentation on the rectangular coordinate system. Next, they participated in a computer-interactive matching-to-sample procedure that trained formula-to-formula and formula-to-graph relations. Then, they were exposed to 40 novel formula-to-graph tests and 10 novel graph-to-formula tests. Seven of the 8 participants showed substantial improvement in identifying formula-to-graph relations; however, in the test of novel graph-to-formula relations, participants tended to select equations in their factored form. Next, we manipulated contextual cues in the form of rules regarding mathematical preferences. First, we informed participants that standard forms of equations were preferred over factored forms. In a subsequent test of 10 additional novel graph-to-formula relations, participants shifted their selections to favor equations in their standard form. This preference reversed during 10 more tests when financial reward was made contingent on correct identification of formulas in factored form. Formula preferences and transformation of novel mathematical and stimulus functions are discussed.

  15. Stimulus type affects Wada memory performance.

    PubMed

    Testa, S Marc; Ward, Julianna; Crone, Nathan E; Brandt, Jason

    2008-10-01

    The effects of amytal injection side, seizure focus laterality, and stimulus type (real and line-drawn objects, printed words, and faces) on recognition memory were studied during the Wada procedure. To-be-remembered stimuli were presented during cerebral anesthesia to 35 patients with left temporal lobe epilepsy (LTLE) and 28 patients with right temporal lobe epilepsy (RTLE), all with left hemisphere language dominance. In both groups, recognition of real and line-drawn objects was best after anesthetization of the lesional hemisphere. Recognition of faces was poor after either injection in patients with RTLE, but only after right injection in patients with LTLE. Conversely, recognition of words by patients with LTLE was impaired equally after either injection, but more so after left than right injection in patients with RTLE. The findings suggest that (1) real and line-drawn objects are "dually encoded" and memory accuracy depends on seizure focus laterality, and (2) accuracy in recognition of words and faces is related to seizure focus laterality, but may also depend on the language dominance of the hemisphere being assessed.

  16. Stimulus length uncertainty with dichotic digit recognition.

    PubMed

    Strouse, A; Wilson, R H

    1999-04-01

    Dichotic digit listening was made more difficult by interleaving one-, two-, three-, and four-pair digits within a test list in which the subjects did not know a priori the number of digit pairs presented on a given trial, thereby introducing listener uncertainty. Twenty right-handed (mean age = 26.8 years) and 20 left-handed adults (mean age = 24.0) with normal hearing and 40 right-handed adults in the 60- to 75-years age range (mean age = 67.2) with mild-to-moderate sensorineural hearing loss were evaluated. Compared to traditional paradigms, the uncertainty of stimulus length (one, two, three, or four pairs) reduced overall recognition performance on stimuli presented to both ears of all groups, but the reduction was more pronounced for the left ear than for the right ear. The recognition performance of the right-handed subjects was more homogeneous than the performance of the left-handed subjects. In comparison to the young subjects, the 60- to 75-year-old group had substantially reduced recognition performance.

  17. The Embryonic Septum and Ventral Pallium, New Sources of Olfactory Cortex Cells

    PubMed Central

    de Carlos, Juan A.

    2012-01-01

    The mammalian olfactory cortex is a complex structure located along the rostro-caudal extension of the ventrolateral prosencephalon, which is divided into several anatomically and functionally distinct areas: the anterior olfactory nucleus, piriform cortex, olfactory tubercle, amygdaloid olfactory nuclei, and the more caudal entorhinal cortex. Multiple forebrain progenitor domains contribute to the cellular diversity of the olfactory cortex, which is invaded simultaneously by cells originating in distinct germinal areas in the dorsal and ventral forebrain. Using a combination of dye labeling techniques, we identified two novel areas that contribute cells to the developing olfactory cortices, the septum and the ventral pallium, from which cells migrate along a radial and then a tangential path. We characterized these cell populations by comparing their expression of calretinin, calbindin, reelin and Tbr1 with that of other olfactory cell populations. PMID:22984546

  18. Context-Dependent Olfactory Learning in an Insect

    ERIC Educational Resources Information Center

    Matsumoto, Yukihisa; Mizunami, Makoto

    2004-01-01

    We studied the capability of the cricket "Gryllus bimaculatus" to select one of a pair of odors and to avoid the other in one context and to do the opposite in another context. One group of crickets was trained to associate one of a pair of odors (conditioned stimulus, CS1) with water reward (appetitive unconditioned stimulus, US+) and another…

  19. A Robust Feedforward Model of the Olfactory System

    PubMed Central

    Zhang, Yilun; Sharpee, Tatyana O.

    2016-01-01

    Most natural odors have sparse molecular composition. This makes the principles of compressed sensing potentially relevant to the structure of the olfactory code. Yet, the largely feedforward organization of the olfactory system precludes reconstruction using standard compressed sensing algorithms. To resolve this problem, recent theoretical work has shown that signal reconstruction could take place as a result of a low dimensional dynamical system converging to one of its attractor states. However, the dynamical aspects of optimization slowed down odor recognition and were also found to be susceptible to noise. Here we describe a feedforward model of the olfactory system that achieves both strong compression and fast reconstruction that is also robust to noise. A key feature of the proposed model is a specific relationship between how odors are represented at the glomeruli stage, which corresponds to a compression, and the connections from glomeruli to third-order neurons (neurons in the olfactory cortex of vertebrates or Kenyon cells in the mushroom body of insects), which in the model corresponds to reconstruction. We show that should this specific relationship hold true, the reconstruction will be both fast and robust to noise, and in particular to the false activation of glomeruli. The predicted connectivity rate from glomeruli to third-order neurons can be tested experimentally. PMID:27065441

  20. Neural map formation in the mouse olfactory system.

    PubMed

    Takeuchi, Haruki; Sakano, Hitoshi

    2014-08-01

    In the mouse olfactory system, odorants are detected by ~1,000 different odorant receptors (ORs) produced by olfactory sensory neurons (OSNs). Each OSN expresses only one functional OR species, which is referred to as the "one neuron-one receptor" rule. Furthermore, OSN axons bearing the same OR converge to a specific projection site in the olfactory bulb (OB) forming a glomerular structure, i.e., the "one glomerulus-one receptor" rule. Based on these basic rules, binding signals of odorants detected by OSNs are converted to topographic information of activated glomeruli in the OB. During development, the glomerular map is formed by the combination of two genetically programmed processes: one is OR-independent projection along the dorsal-ventral axis, and the other is OR-dependent projection along the anterior-posterior axis. The map is further refined in an activity-dependent manner during the neonatal period. Here, we summarize recent progress of neural map formation in the mouse olfactory system.

  1. Enhanced trapping of stable flies via olfactory and visual cues

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Adult stable flies are highly attracted to the so-called Alsynite cylinder trap; however this trap is expensive. Here we report the development of a cheaper and better white panel trap with options of adding visual and olfactory stimuli for enhanced stable fly trapping. The white panel trap attracte...

  2. Distinct Neural Mechanisms Mediate Olfactory Memory Formation at Different Timescales

    ERIC Educational Resources Information Center

    McNamara, Ann Marie; Magidson, Phillip D.; Linster, Christiane; Wilson, Donald A.; Cleland, Thomas A.

    2008-01-01

    Habituation is one of the oldest forms of learning, broadly expressed across sensory systems and taxa. Here, we demonstrate that olfactory habituation induced at different timescales (comprising different odor exposure and intertrial interval durations) is mediated by different neural mechanisms. First, the persistence of habituation memory is…

  3. Virtual vision system with actual flavor by olfactory display

    NASA Astrophysics Data System (ADS)

    Sakamoto, Kunio; Kanazawa, Fumihiro

    2010-11-01

    The authors have researched multimedia system and support system for nursing studies on and practices of reminiscence therapy and life review therapy. The concept of the life review is presented by Butler in 1963. The process of thinking back on one's life and communicating about one's life to another person is called life review. There is a famous episode concerning the memory. It is called as Proustian effects. This effect is mentioned on the Proust's novel as an episode that a story teller reminds his old memory when he dipped a madeleine in tea. So many scientists research why smells trigger the memory. The authors pay attention to the relation between smells and memory although the reason is not evident yet. Then we have tried to add an olfactory display to the multimedia system so that the smells become a trigger of reminding buried memories. An olfactory display is a device that delivers smells to the nose. It provides us with special effects, for example to emit smell as if you were there or to give a trigger for reminding us of memories. The authors have developed a tabletop display system connected with the olfactory display. For delivering a flavor to user's nose, the system needs to recognition and measure positions of user's face and nose. In this paper, the authors describe an olfactory display which enables to detect the nose position for an effective delivery.

  4. Optophysiological analysis of associational circuits in the olfactory cortex

    PubMed Central

    Hagiwara, Akari; Pal, Sumon K.; Sato, Tomokazu F.; Wienisch, Martin; Murthy, Venkatesh N.

    2012-01-01

    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 cortices (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. PMID:22529781

  5. Windscapes and olfactory foraging in a large carnivore.

    PubMed

    Togunov, Ron R; Derocher, Andrew E; Lunn, Nicholas J

    2017-04-12

    The theoretical optimal olfactory search strategy is to move cross-wind. Empirical evidence supporting wind-associated directionality among carnivores, however, is sparse. We examined satellite-linked telemetry movement data of adult female polar bears (Ursus maritimus) from Hudson Bay, Canada, in relation to modelled winds, in an effort to understand olfactory search for prey. In our results, the predicted cross-wind movement occurred most frequently at night during winter, the time when most hunting occurs, while downwind movement dominated during fast winds, which impede olfaction. Migration during sea ice freeze-up and break-up was also correlated with wind. A lack of orientation during summer, a period with few food resources, likely reflected reduced cross-wind search. Our findings represent the first quantitative description of anemotaxis, orientation to wind, for cross-wind search in a large carnivore. The methods are widely applicable to olfactory predators and their prey. We suggest windscapes be included as a habitat feature in habitat selection models for olfactory animals when evaluating what is considered available habitat.

  6. Olfactory Receptor Response to the Cockroach Sexual Attractant.

    PubMed

    Boeckh, J; Priesner, E; Schneider, D; Jacobson, M

    1963-08-23

    The recently isolated sex attractant of the female American cockroach elicits an electical response in the antennae of males, females, and mymphs of this species. These electroantennograms are known to be summated receptor (generator) potentials of many olfactory sensillae stimulated simultaneously. Many other odorous substances also elicit such responses in the cockroach antenna.

  7. Olfactory-Induced Synesthesias: A Review and Model

    ERIC Educational Resources Information Center

    Stevenson, Richard J.; Tomiczek, Caroline

    2007-01-01

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

  8. Olfactory-visual integration facilitates perception of subthreshold negative emotion.

    PubMed

    Novak, Lucas R; Gitelman, Darren R; Schuyler, Brianna; Li, Wen

    2015-10-01

    A fast growing literature of multisensory emotion integration notwithstanding, the chemical senses, intimately associated with emotion, have been largely overlooked. Moreover, an ecologically highly relevant principle of "inverse effectiveness", rendering maximal integration efficacy with impoverished sensory input, remains to be assessed in emotion integration. Presenting minute, subthreshold negative (vs. neutral) cues in faces and odors, we demonstrated olfactory-visual emotion integration in improved emotion detection (especially among individuals with weaker perception of unimodal negative cues) and response enhancement in the amygdala. Moreover, while perceptual gain for visual negative emotion involved the posterior superior temporal sulcus/pSTS, perceptual gain for olfactory negative emotion engaged both the associative olfactory (orbitofrontal) cortex and amygdala. Dynamic causal modeling (DCM) analysis of fMRI timeseries further revealed connectivity strengthening among these areas during crossmodal emotion integration. That multisensory (but not low-level unisensory) areas exhibited both enhanced response and region-to-region coupling favors a top-down (vs. bottom-up) account for olfactory-visual emotion integration. Current findings thus confirm the involvement of multisensory convergence areas, while highlighting unique characteristics of olfaction-related integration. Furthermore, successful crossmodal binding of subthreshold aversive cues not only supports the principle of "inverse effectiveness" in emotion integration but also accentuates the automatic, unconscious quality of crossmodal emotion synthesis.

  9. Odor Memory Stability after Reinnervation of the Olfactory Bulb

    PubMed Central

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

    2012-01-01

    The olfactory system, particularly the olfactory epithelium, presents a unique opportunity to study the regenerative capabilities of the brain, because of its ability to recover after damage. In this study, we ablated olfactory sensory neurons with methimazole and followed the anatomical and functional recovery of circuits expressing genetic markers for I7 and M72 receptors (M72-IRES-tau-LacZ and I7-IRES-tau-GFP). Our results show that 45 days after methimazole-induced lesion, axonal projections to the bulb of M72 and I7 populations are largely reestablished. Furthermore, regenerated glomeruli are re-formed within the same areas as those of control, unexposed mice. This anatomical regeneration correlates with functional recovery of a previously learned odorant-discrimination task, dependent on the cognate ligands for M72 and I7. Following regeneration, mice also recover innate responsiveness to TMT and urine. Our findings show that regeneration of neuronal circuits in the olfactory system can be achieved with remarkable precision and underscore the importance of glomerular organization to evoke memory traces stored in the brain. PMID:23071557

  10. Differential coding by two olfactory subsystems in the honeybee brain.

    PubMed

    Carcaud, Julie; Hill, Thomas; Giurfa, Martin; Sandoz, Jean-Christophe

    2012-08-01

    Sensory systems use parallel processing to extract and process different features of environmental stimuli. Parallel processing has been studied in the auditory, visual, and somatosensory systems, but equivalent research in the olfactory modality is scarce. The honeybee Apis mellifera is an interesting model for such research as its relatively simple brain contains a dual olfactory system, with a clear neural dichotomy from the periphery to higher-order centers, based on two main neuronal tracts [medial (m) and lateral (l) antenno-protocerebral tract (APT)]. The function of this dual system is as yet unknown, and attributes like odor quality and odor quantity might be separately encoded in these subsystems. We have thus studied olfactory coding at the input of both subsystems, using in vivo calcium imaging. As one of the subsystems (m-APT) has never been imaged before, a novel imaging preparation was developed to this end, and responses to a panel of aliphatic odorants at different concentrations were compared in both subsystems. Our data show a global redundancy of olfactory coding at the input of both subsystems but unravel some specificities for encoding chemical group and carbon chain length of odor molecules.

  11. Penguins reduced olfactory receptor genes common to other waterbirds

    PubMed Central

    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

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

    NASA Astrophysics Data System (ADS)

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

    2017-01-01

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

  13. The Olfactory Neural Epithelium As a Tool in Neuroscience.

    PubMed

    Lavoie, Joëlle; Gassó Astorga, Patricia; Segal-Gavish, Hadar; Wu, YeeWen Candace; Chung, Youjin; Cascella, Nicola G; Sawa, Akira; Ishizuka, Koko

    2017-02-01

    Capturing both dynamic changes (state) and persistent signatures (trait) directly associated with disease at the molecular level is crucial in modern medicine. The olfactory neural epithelium, easily accessible in clinical settings, is a promising surrogate model in translational brain medicine, complementing the limitations in current engineered cell models.

  14. Expression and differential localization of xenobiotic transporters in the rat olfactory neuro-epithelium.

    PubMed

    Thiebaud, Nicolas; Menetrier, Franck; Belloir, Christine; Minn, Anne-Laure; Neiers, Fabrice; Artur, Yves; Le Bon, Anne-Marie; Heydel, Jean-Marie

    2011-11-14

    Transporters, such as multidrug resistance P-glycoproteins (MDR), multidrug resistance-related proteins (MRP) and organic anion transporters (OATs), are involved in xenobiotic metabolism, particularly the cellular uptake or efflux of xenobiotics (and endobiotics) or their metabolites. The olfactory epithelium is exposed to both inhaled xenobiotics and those coming from systemic circulation. This tissue has been described as a pathway for xenobiotics to the brain via olfactory perineural space. Thereby, olfactory transporters and xenobiotic metabolizing enzymes, dedicated to the inactivation and the elimination of xenobiotics, have been involved in the toxicological protection of the brain, the olfactory epithelium itself and the whole body. These proteins could also have a role in the preservation of the olfactory sensitivity by inactivation and clearance of the excess of odorant molecules from the perireceptor space. The goal of the present study was to increase our understanding of the expression and the localization of transporters in this tissue. For most of the studied transporters, we observed an opposite mRNA expression pattern (RT-PCR) in the olfactory epithelium compared to the liver, which is considered to be the main metabolic organ. Olfactory epithelium mainly expressed efflux transporters (MRP, MDR). However, a similar pattern was observed between the olfactory epithelium and the olfactory bulb. We also demonstrate distinct cellular immunolocalization of the transporters in the olfactory epithelium. As previously reported, Mrp1 was mainly found in the supranuclear portions of supporting cells. In addition, Mrp3 and Mrp5 proteins, which were detected for the first time in olfactory epithelium, were localized to the olfactory neuron layer, while Mdr1 was localized to the capillary endothelium of lymphatic vessels in the subepithelial region. The pattern of expression and the distinct localization of the olfactory transporters showed in this work may

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

    PubMed

    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.

  16. Olfactory subsystems in the honeybee: sensory supply and sex specificity.

    PubMed

    Kropf, Jan; Kelber, Christina; Bieringer, Kathrin; Rössler, Wolfgang

    2014-09-01

    The antennae of honeybee (Apis mellifera) workers and drones differ in various aspects. One striking difference is the presence of Sensilla basiconica in (female) workers and their absence in (male) drones. We investigate the axonal projection patterns of olfactory receptor neurons (ORNs) housed in S. basiconica in honeybee workers by using selective anterograde labeling with fluorescent tracers and confocal-microscopy analysis of axonal projections in antennal lobe glomeruli. Axons of S. basiconica-associated ORNs preferentially projected into a specific glomerular cluster in the antennal lobe, namely the sensory input-tract three (T3) cluster. T3-associated glomeruli had previously been shown to be innervated by uniglomerular projection (output) neurons of the medial antennal lobe tract (mALT). As the number of T3 glomeruli is reduced in drones, we wished to determine whether this was associated with the reduction of glomeruli innervated by medial-tract projection neurons. We retrogradely traced mALT projection neurons in drones and counted the innervated glomeruli. The number of mALT-associated glomeruli was strongly reduced in drones compared with workers. The preferential projections of S. basiconica-associated ORNs in T3 glomeruli together with the reduction of mALT-associated glomeruli support the presence of a female (worker)-specific olfactory subsystem that is partly innervated by ORNs from S. basiconica and is associated with the T3 cluster of glomeruli and mALT projection neurons. We propose that this olfactory subsystem supports parallel olfactory processing related to worker-specific olfactory tasks such as the coding of colony odors, colony pheromones and/or odorants associated with foraging on floral resources.

  17. Olfactory and gustatory functions and its relation to body weight.

    PubMed

    Skrandies, Wolfgang; Zschieschang, Romy

    2015-04-01

    In the present study we investigated the influence of body weight as defined by BMI on gustatory and olfactory perception. A total of 66 healthy adults (41 females; 25 males) participated in psychophysical measurements using the "Sniffin' Sticks" test and "Taste Strips" test. Odor thresholds as well as discrimination and identification performance were determined. Tests of gustatory function involved the identification and thresholds of sweet, sour, salty, or bitter taste. In this study, all subjects were healthy participants in a middle age range (between 20 and 56 years of age). Persons with an extreme BMI value were excluded. Subjects were classified according to their BMI in four groups: (1) 15-19.9 kg/m, (2) 20-24.9 kg/m, (3) 25-29.9 kg/m, and (4) >30 kg/m. We did not observe an overall effect of BMI on general sensory sensitivity. There was a significant influence of BMI on olfactory thresholds (F(3,62)=2.79; p<0.047) which increased with increasing BMI. In a similar line, the gustatory thresholds for "salty" were significantly higher with higher BMI (F(3,62)=3.06; p<0.035). Olfactory discrimination and identification was not affected by BMI. Thresholds for odor and sweet or salty taste were also correlated. Our data show that body weight influences gustatory and olfactory perception in healthy adults. Increasing BMI is associated with a decrease in olfactory and taste sensitivity. These findings may have implications for the understanding of pathophysiological mechanisms in patients.

  18. Gender and Stimulus Control of Smoking Behavior

    PubMed Central

    Frandsen, Mai; Dunbar, Michael S.; Shiffman, Saul

    2015-01-01

    Introduction: Gender differences in smoking behavior have been proposed to account for poorer outcomes among women attempting to quit. Specifically, it has been suggested that women’s smoking behavior is less motivated by nicotine-seeking and more driven by environmental cues. To date, however, few real-world studies have examined the hypothesis that women’s smoking is under greater stimulus control. Methods: One hundred and ninety four daily smokers (men = 107; women = 87) completed 3 weeks of ecological momentary assessment (EMA) monitoring that provided data on real-world smoking behavior by reporting on situational contexts shown by previous research to influence smoking behavior (including social setting, cigarette availability, alcohol consumption, and mood). Results: Analyses of particular cues found few gender differences; however, men’s smoking increased to a greater extent compared with women’s when they were with others who were smoking. Idiographic analyses that allow individual subjects to have different directions of linkage to situational cues also were conducted to assess how predictable subjects’ smoking was from a range of contextual characteristics. Compared with women, men’s smoking was significantly more closely tied to food/alcohol consumption and tended to be more closely tied to social context. No other gender differences were found. Conclusions: EMA analyses suggest that men and women are similarly influenced by cues, including mood. Where there were gender differences, it was men rather than women whose smoking behavior was more influenced by cues. The data contradict the hypothesis that women’s smoking is more influenced by cues. PMID:25762752

  19. Olfactory Bulb Glomerular NMDA Receptors Mediate Olfactory Nerve Potentiation and Odor Preference Learning in the Neonate Rat

    PubMed Central

    Harley, Carolyn W.; Yuan, Qi

    2012-01-01

    Rat pup odor preference learning follows pairing of bulbar beta-adrenoceptor activation with olfactory input. We hypothesize that NMDA receptor (NMDAR)-mediated olfactory input to mitral cells is enhanced during training, such that increased calcium facilitates and shapes the critical cAMP pattern. Here, we demonstrate, in vitro, that olfactory nerve stimulation, at sniffing frequencies, paired with beta-adrenoceptor activation, potentiates olfactory nerve-evoked mitral cell firing. This potentiation is blocked by a NMDAR antagonist and by increased inhibition. Glomerular dishinhibtion also induces NMDAR-sensitive potentiation. In vivo, in parallel, behavioral learning is prevented by glomerular infusion of an NMDAR antagonist or a GABAA receptor agonist. A glomerular GABAA receptor antagonist paired with odor can induce NMDAR-dependent learning. The NMDA GluN1 subunit is phosphorylated in odor-specific glomeruli within 5 min of training suggesting early activation, and enhanced calcium entry, during acquisition. The GluN1 subunit is down-regulated 3 h after learning; and at 24 h post-training the GluN2B subunit is down-regulated. These events may assist memory stability. Ex vivo experiments using bulbs from trained rat pups reveal an increase in the AMPA/NMDA EPSC ratio post-training, consistent with an increase in AMPA receptor insertion and/or the decrease in NMDAR subunits. These results support a model of a cAMP/NMDA interaction in generating rat pup odor preference learning. PMID:22496886

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

    PubMed

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

    2008-12-05

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