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Sample records for stimulation dishabituates olfactory

  1. Neonatal Habituation and Dishabituation to Tactile Stimulation during Sleep.

    ERIC Educational Resources Information Center

    Kisilevsky, Barbara S.; Muir, Darwin W.

    1984-01-01

    Two experiments were conducted to (1) replicate the findings of habituation of behavioral responding to a tactile stimulus assuring state control and (2) demonstrate dishabituation either by reinstatement of responding to the original, habituated stimulus or to novel stimuli either within or between modalities. Subjects were newborn Caucasian…

  2. Stimulation of olfactory receptors alters regulation of [Cai] in olfactory neurons of the catfish (Ictalurus punctatus).

    PubMed

    Restrepo, D; Boyle, A G

    1991-03-01

    Intracellular calcium was measured in single olfactory neurons from the channel catfish (Ictalurus punctatus) using the fluorescent Ca2+ indicator fura 2. In 5% of the cells, olfactory stimuli (amino acids) elicited an influx of calcium through the plasma membrane which led to a rapid transient increase in intracellular calcium concentration. Amino acids did not induce release of calcium from internal stores in these cells. Some cells responded specifically to one stimulus (L-alanine, L-arginine, L-norleucine and L-glutamate) while one cell responded to all stimuli. An increase in intracellular calcium could also be elicited in 50% of the cells by direct G-protein stimulation using aluminum fluoride. Because the fraction of cells which respond to direct G-protein stimulation is substantially larger than the fraction of cells responding to amino acids, we tested for possible damage of receptor proteins due to exposure of the olfactory neurons to papain during cell isolation. We find that pretreatment with papain does not alter specific binding of L-alanine and L-arginine to olfactory receptor sites in isolated olfactory cilia. The results are discussed in terms of their relevance to olfactory transduction. PMID:2051471

  3. Long-term recording of olfactory and vomeronasal stimulant-induced waves from the turtle main olfactory bulb and accessory olfactory bulb.

    PubMed

    Kashiwayanagi, M; Taniguchi, M; Shoji, T; Kurihara, K

    1997-08-01

    Recording of stimulant-induced waves (bulbar responses) from the main olfactory bulb is a useful tool for measuring quantitative stable olfactory responses. There is a good relationship between the olfactory bulbar response, olfactory nerve response and electroolfactogram (EOG), suggesting that the bulbar response reflects events in receptor cells. The modern whole-cell recording technique offers direct information on olfactory transduction in single cells, but it requires long experimental periods and many animals. On the other hand, analysis of bulbar responses provides useful information and requires the use of few animals. For example, we found that cAMP-increasing and IP3-increasing odorants were not distinctly received by the turtle olfactory organ by measuring olfactory bulbar responses and analyzed with a multidimensional scaling from about 60 animals. However, to record similar odor responses from isolated turtle olfactory neurons, at least 200 animals would be necessary. Bulbar responses are recorded with electrodes implanted into or located on the main olfactory bulb. When electrodes are located on the olfactory bulb surface, it is possible to record stable responses over a period of 3 days. These methods were applied successfully to the accessory olfactory bulb. In this paper, we describe the protocols used for recording of the stimulant-induced waves from the main and accessory olfactory bulb. PMID:9385067

  4. Cross-adaptation to odor stimulation of olfactory receptor cells in the box turtle, Terrapene carolina.

    PubMed

    Tonosaki, K

    1993-01-01

    Electrical recording from small twigs of olfactory nerve and electro-olfactogram (EOG) from olfactory epithelium in a turtle shows that olfactory receptors in the nose are responsive to various odors. I have used the effects of cross-adaptation to odor stimulation on the olfactory receptors to investigate the stimulus-specific components of these responses and to provide information about the responsiveness of cells. The results of the cross-adaptation experiments strongly support the hypothesis that different categories of receptor cells exist in the olfactory epithelium. PMID:8386588

  5. Intramodal Olfactory Priming of Positive and Negative Odors in Humans Using Respiration-Triggered Olfactory Stimulation (RETROS).

    PubMed

    Hoffmann-Hensel, Sonja Maria; Freiherr, Jessica

    2016-09-01

    Priming describes the principle of modified stimulus perception that occurs due to a previously presented stimulus. Although we have begun to understand the mechanisms of crossmodal priming, the concept of intramodal olfactory priming remains relatively unexplored. Therefore, we applied positive and negative odors using respiration-triggered olfactory stimulation (RETROS), enabling us to record the skin conductance response (SCR) and breathing data without a crossmodal cueing error and measure reaction times (RTs) for olfactory tasks. RT, SCR, and breathing data revealed that negative odors were perceived significantly more arousing than positive ones. In a second experiment, 2 odors were applied during consecutive respirations. Here, we observed intramodal olfactory priming effects: A negative odor preceded by a positive odor was rated as more pleasant than when the same odor was preceded by a negative odor. Additionally, a longer identification RT was found for the second compared with the first odor. We interpret this as increased "perceptual load" due to incomplete first odor processing while the second odor was presented. Furthermore, intramodal priming can be considered a possible reason for the increase of identification RT. The use of RETROS led to these novel insights into olfactory processing beyond crossmodal interaction by providing a noncued unimodal olfactory test, and therefore, RETROS can be used in the experimental design of future olfactory studies. PMID:27170666

  6. Pupillary responses to intranasal trigeminal and olfactory stimulation.

    PubMed

    Schneider, Christine B; Ziemssen, Tjalf; Schuster, Benno; Seo, Han-Seok; Haehner, Antje; Hummel, Thomas

    2009-07-01

    The aim of the present study was to investigate whether pupillary responses to odorous stimuli reflect their intensity or hedonic tone. A total of 21 healthy subjects participated in the study. Using a computer-controlled olfactometer, subjects received intranasal stimuli including odors of rose (PEA; 2 concentrations), lemon and rotten eggs, plus the trigeminal irritant CO2 (also at two concentrations). Changes in the pupil diameter were obtained ipsilaterally to the side of stimulus presentation. Both trigeminal and olfactory stimulation produced an increase in pupillary diameter. Latencies for pupillary reaction were fastest for the higher concentration of CO2 and slowest after the presentation of PEA at the low concentration. Response amplitudes were largest in response to stimulation with CO2 at the high concentration, while they were smallest in response to odorous stimulation with PEA. Response latencies decreased with increasing stimulus intensity. No such correlation was found for hedonic ratings and pupillary reactions. Thus, the change in the pupillary diameter indicates differences between stimulus modalities and stimulus strength, but not pleasantness or unpleasantness of the odors. PMID:19484181

  7. Effects of Odor Stimulation on Antidromic Spikes in Olfactory Sensory Neurons

    PubMed Central

    Scott, John W.; Sherrill, Lisa

    2008-01-01

    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

  8. 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

  9. Air-stepping in neonatal rats: A comparison of L-dopa injection and olfactory stimulation.

    PubMed

    Jamon, M; Maloum, I; Riviere, G; Bruguerolle, B

    2002-12-01

    The kinematic parameters of air-stepping induced by 2 methods known to elicit locomotion (olfactory stimulation vs. L-dopa injection) were compared in 3-day-old rats. In the 1st stage, suspended pups were induced to step with an olfactory stimulus of soiled shavings from the nest. In the 2nd stage, they received a subcutaneous injection of L-dopa. Their movements were faster, with a larger amplitude and a phase delay in ipsilateral coupling. Third, the olfactory stimulus was presented in conjunction with L-dopa. The characteristics of locomotion returned to the same level as with the olfactory stimulus alone. These results suggest that olfactory stimulation involves higher nerve centers able to modulate the dopaminergic pathways. They are discussed in relation to the neural structure involved in locomotion. PMID:12492300

  10. The Impact of Deep Brain Stimulation on Sleep and Olfactory Function in Parkinson’s Disease

    PubMed Central

    Breen, David P; Low, Hu Liang; Misbahuddin, Anjum

    2015-01-01

    Objective: Relatively little is known about the effects of deep brain stimulation on non-motor symptoms. The aim of this pilot study was to assess the impact of deep brain stimulation on sleep and olfactory function in Parkinson’s disease. Methods: Subjective sleep quality and olfactory testing were performed on 11 consecutive Parkinson’s disease patients (eight men and three women) undergoing bilateral subthalamic nucleus stimulation. All patients consented to undergo clinical assessments prior to the procedure, and at regular intervals afterwards. Results: Subjective sleep quality improved at six months following deep brain stimulation and this benefit was sustained in the majority of patients at later follow-up assessments. There was no significant change in olfactory function following deep brain stimulation. Conclusions: In addition to having beneficial effects on motor function and quality of life, bilateral subthalamic nucleus stimulation improves subjective sleep quality in Parkinson’s disease. PMID:26535069

  11. 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. PMID:26710120

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

    PubMed Central

    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. PMID:26710120

  13. Dishabituation Produces Interactions during Multiple Schedules

    ERIC Educational Resources Information Center

    McSweeney, Frances K.; Kowal, Benjamin P.; Murphy, Eric S.; Isava, Duane M.

    2004-01-01

    McSweeney and Weatherly (1998) argued that differential habituation to the reinforcer contributes to the behavioral interactions observed during multiple schedules. The present experiment confirmed that introducing dishabituators into one component of a multiple schedule increases response rate in the other, constant, component. During baseline,…

  14. Brain-state–independent neural representation of peripheral stimulation in rat olfactory bulb

    PubMed Central

    Gong, Ling; Xu, Fuqiang

    2011-01-01

    It is critical for normal brains to perceive the external world precisely and accurately under ever-changing operational conditions, yet the mechanisms underlying this fundamental brain function in the sensory systems are poorly understood. To address this issue in the olfactory system, we investigated the responses of olfactory bulbs to odor stimulations under different brain states manipulated by anesthesia levels. Our results revealed that in two brain states, where the spontaneous baseline activities differed about twofold based on the local field potential (LFP) signals, the levels of neural activities reached after the same odor stimulation had no significant difference. This phenomenon was independent of anesthetics (pentobarbital or chloral hydrate), stimulating odorants (ethyl propionate, ethyl butyrate, ethyl valerate, amyl acetate, n-heptanal, or 2-heptanone), odor concentrations, and recording sites (the mitral or granular cell layers) for LFPs in three frequency bands (12–32 Hz, 33–64 Hz, and 65–90 Hz) and for multiunit activities. Furthermore, the activity patterns of the same stimulation under these two brain states were highly similar at both LFP and multiunit levels. These converging results argue the existence of mechanisms in the olfactory bulbs that ensure the delivery of peripheral olfactory information to higher olfactory centers with high fidelity under different brain states. PMID:21321196

  15. Habituation of glomerular responses in the olfactory bulb following prolonged odor stimulation reflects reduced peripheral input

    PubMed Central

    Ogg, M. Cameron; Bendahamane, Mounir; Fletcher, Max L.

    2015-01-01

    Following prolonged odor stimulation, output from olfactory bulb (OB) mitral/tufted (M/T) cells is decreased in response to subsequent olfactory stimulation. Currently, it is unclear if this decrease is a function of adaptation of peripheral olfactory sensory neuron (OSN) responses or reflects depression of bulb circuits. We used wide-field calcium imaging in anesthetized transgenic GCaMP2 mice to compare excitatory glomerular layer odor responses before and after a 30-s odor stimulation. Significant habituation of subsequent glomerular odor responses to both the same and structurally similar odorants was detected with our protocol. To test whether depression of OSN terminals contributed to this habituation, olfactory nerve layer (ON) stimulation was used to drive glomerular layer responses in the absence of peripheral odor activation of the OSNs. Following odor habituation, in contrast to odor-evoked glomerular responses, ON stimulation-evoked glomerular responses were not habituated. The difference in response between odor and electrical stimulation following odor habituation provides evidence that odor response reductions measured in the glomerular layer of the OB are most likely the result of OSN adaptation processes taking place in the periphery. PMID:26441516

  16. [Interests of an olfactory stimulation activity in a nursing home].

    PubMed

    Garnaud, Mahlia; Rexand, Franck

    2016-01-01

    The comparison between the memories productions of residents in a nursing home through two reminiscence activities, one including olfaction and not the other one, can highlight an increasing occurrence of recent memories in the case of olfactory activity. A longer talk time is also observed and a better self-esteem can be assessed. This suggests the possibility of a specific relational and psychotherapeutic work. PMID:26976316

  17. Gonadotropin releasing hormone (GnRH)--a novel olfactory stimulant in fish.

    PubMed

    Andersen, O; Døving, K B

    1991-08-01

    The aim of this study was to elucidate the putative role of the gonadotropin releasing hormone (GnRH or LHRH) as an olfactory stimulant in fish. We report for the first time extreme sensitivity of the olfactory organ in the rainbow trout (Oncorhynchus mykiss) to GnRH. Recordings of the electroolfactogram (EOG) showed an electrophysiological response to 10(-16) M GnRH four times the amplitude of the response to a fresh water control stimulus. By stimulating the olfactory epithelium with several GnRH analogs and fragments of the decapeptide, the biologically active region of GnRH could be partly elucidated. The response profile of GnRH differed from that of the positive control odorant L-alanine, suggesting that separate receptors or receptor cells are involved. We propose that this potent odorant may act as a reproductive pheromone in fish. PMID:1912479

  18. Olfactory nerve stimulation-induced calcium signaling in the mitral cell distal dendritic tuft.

    PubMed

    Yuan, Q; Knöpfel, T

    2006-04-01

    Olfactory receptor neuron axons form the olfactory nerve (ON) and project to the glomerular layer of the olfactory bulb, where they form excitatory synapses with terminal arborizations of the mitral cell (MC) tufted primary dendrite. Clusters of MC dendritic tufts define olfactory glomeruli, where they involve in complex synaptic interactions. The computational function of these cellular interactions is not clear. We used patch-clamp electrophysiology combined with whole field or two-photon Ca2+ imaging to study ON stimulation-induced Ca2+ signaling at the level of individual terminal branches of the MC primary dendrite in mice. ON-evoked subthreshold excitatory postsnaptic potentials induced Ca2+ transients in the MC tuft dendrites that were spatially inhomogeneous, exhibiting discrete "hot spots." In contrast, Ca2+ transients induced by backpropagating action potentials occurred throughout the dendritic tuft, being larger in the thin terminal dendrites than in the base of the tuft. Single ON stimulation-induced Ca2+ transients were depressed by the NMDA receptor antagonist D-aminophosphonovaleric acid (D-APV), increased with increasing stimulation intensity, and typically showed a prolonged rising phase. The synaptically induced Ca2+ signals reflect, at least in part, dendrodendritic interactions that support intraglomerular coupling of MCs and generation of an output that is common to all MCs associated with one glomerulus. PMID:16319202

  19. Slow potentials of the turtle olfactory bulb in response to odor stimulation of the nose.

    PubMed

    Beuerman, R W

    1975-10-24

    Odor stimulation of the nose in the box turtle and the gopher tortoise produced a characteristic series of slow potentials in the olfactory bulb which were referred to as the odor evoked response. When recorded with direct coupling, the odor evoked response had 3 components: wave I, a short duration monophasic event; wave II, a long duration variation in the DC potential; and wave III, an oscillatory potential superimposed on wave II. Waves I and II were negative at bulbar surfaces receiving olfactory input and positive deep within the bulb. This series of potentials could be evoked by 3 methods of odor stimulation: (1) large puffs delivered from odorant test bottles, (2) small puffs delivered from a syringe and (3) continuous flow with concentration and nasal flow rate parameters controlled by an olfactometer. When the odor evoked response was recorded at a bulbar locus, these potentials were seen in response to each stimulation and the amplitudes of each wave were reproducible with the same stimulus. The amplitudes of the 3 waves were compared in the gopher tortoise and differed with the 3 odorants tested--high purity geraniol, technical grade geraniol and amyl acetate. Odorant concentration also directly affected the response amplitudes of all 3 wave components. The amplitudes of waves I and III markedly decreased with closely spaced stimulations recovering to near the initial values when the interstimulus interval was increased severalfold. This series of sensory evoked potentials is considered to reflect the processing of odor information from the olfactory receptors by the olfactory bulb. PMID:1175040

  20. Stimulation of Ca(2+)-regulated olfactory phospholipase C by amino acids.

    PubMed

    Lo, Y H; Bradley, T M; Rhoads, D E

    1993-11-23

    L-Amino acids are potent olfactory stimuli for Atlantic salmon. A plasma membrane fraction, previously shown to be rich in amino acid binding sites, was prepared from olfactory rosettes of Atlantic salmon (Salmo salar) and utilized to investigate the role of phosphatidylinositol 4,5-bisphosphate (PIP2) hydrolysis in olfactory signal transduction. A cocktail of L-amino acids (Ser, Glu, Lys, and Gly) stimulated PIP2 hydrolysis by phospholipase C (PLC) in a dose-dependent manner with half-maximal stimulation when all amino acids were present at approximately 1 microM. Stimulation of PIP2 hydrolysis by amino acids required GTP gamma S, which alone had no effect on PLC activity. Unlike GTP gamma S, AlF4- and Ca2+ stimulated PIP2 breakdown. Preincubation with 1 mM GDP beta S eliminated the effect of amino acids and AlF4- on PIP2 hydrolysis, suggesting the involvement of G protein regulation. The lack of stimulation by GTP gamma S alone suggested that there was negligible exchange of GTP gamma S for GDP in the absence of odorant. There were no significant effects of amino acids on either adenylate cyclase or guanylate cyclase activities in the membrane preparation under these conditions. The effect of the amino acid cocktail was maximal at 1-10 nM free Ca2+. At or above 100 nM free Ca2+, no effect of amino acids on PIP2 hydrolysis was found. However, between 100 nM and 100 microM, Ca2+ directly stimulated PLC activity in a dose-dependent manner. This stimulation by Ca2+ appeared to be G protein independent because it did not require GTP gamma S and was not inhibited by GDP beta S.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8241123

  1. Social play development in pre-weaning olfactory deprived or stimulated rats.

    PubMed

    Loranca, A; Salas, M

    2001-12-01

    The effect of neonatal unilateral restriction or increased olfactory stimulation upon the development of social play behavior in Wistar strain rats was investigated. Pups were unilaterally thermocauterized in one of the nares on postnatal day 3 (experiment 1), or exposed to amyl acetate from 3 to 19 days of age (experiment 2). Unilateral odor deprivation significantly increased the frequency of boxing, wrestling and pinning in rats of both sexes. However, amyl acetate exposure significantly decreased the frequency of wrestling and pinning in females with no effects in males. The alterations in the development of social play behavior are concurrent with gross physical olfactory bulb modifications that may reflect a significant interference with the integration and transmission of olfactory stimuli to central structures such as septal, entorhinal, cingulate and midline frontal cortices subserving social play behavior. Data suggest that early in life brain mechanisms underlying social play behavior are sensitive to manipulation of neonatal olfactory cues and may participate in the modulation of this behavior. PMID:11720721

  2. The distinctive significance of analgesic drugs and olfactory stimulants on learned pain in mice.

    PubMed

    Nakama-Kitamura, Mototaka

    2014-11-01

    Chronic pain is often intractable to analgesics, and in animals it involves a conditioned nociceptive response (CR) - learned pain. The neural pathways of nociception and olfactory function in the brain overlap. The influence of olfactory stimuli on acute pain has been studied in some depth in animal and human models, but the influence of olfactory stimuli on learned pain has not been understood. We examined the effects of analgesic drugs and olfactory stimulants (preferred or repellent odor) on acute pain, the unconditioned nociceptive response (UCR) and the CR in mice. The CR was provoked by repeated injection of formalin into the hind-paw in animals in the same context, which elicited the typical pain behaviors of paw licking (including biting). The analgesic drugs acetaminophen, fentanyl, gabapentin and fluvoxamine diminished the UCR but did not affect the CR. In contrast, the preferred odor reduced both the UCR and the CR. Our findings suggest that, like chronic pain, the CR is resistant to analgesic drugs and that preferred odor suppress the neural pathways that mediate the CR of pain perception. PMID:25242616

  3. Selective Viral Transduction of Adult-born Olfactory Neurons for Chronic in vivo Optogenetic Stimulation

    PubMed Central

    Lepousez, Gabriel; Alonso, Mariana; Wagner, Sebastian; Gallarda, Benjamin W.; Lledo, Pierre-Marie

    2011-01-01

    Local interneurons are continuously regenerated in the olfactory bulb of adult rodents1-3. In this process, called adult neurogenesis, neural stem cells in the walls of the lateral ventricle give rise to neuroblasts that migrate for several millimeters along the rostral migratory stream (RMS) to reach and incorporate into the olfactory bulb. To study the different steps and the impact of adult-born neuron integration into preexisting olfactory circuits, it is necessary to selectively label and manipulate the activity of this specific population of neurons. The recent development of optogenetic technologies offers the opportunity to use light to precisely activate this specific cohort of neurons without affecting surrounding neurons4,5. Here, we present a series of procedures to virally express Channelrhodopsin2(ChR2)-YFP in a temporally restricted cohort of neuroblasts in the RMS before they reach the olfactory bulb and become adult-born neurons. In addition, we show how to implant and calibrate a miniature LED for chronic in vivo stimulation of ChR2-expressing neurons. PMID:22231709

  4. Effects of gustatory stimulants upon the olfactory epithelium of the bullfrog and the carp.

    PubMed

    Takagi, S F; Iino, M; Yarita, H

    1978-01-01

    Effects of various gustatory stimulants upon the olfactory spithelia were examined in the olfactory bulb of the bullfrog and the carp. 1. The olfactory epithelia of the two animals responded to the salty, bitter- and acid-tasting substances, but not to the sweet ones. 2. The olfactory epithelium of the bullfrog responded immediately to sodium solutions of high concentrations (the "initial response"), but the response to those of low concentrations showed long latency (the "delayed response"). In the carp, the "initial response" was found, while the "delayed response" was not in most cases. A "negative" delayed response was found only infrequently. 3. Responses only to high alkali or acid solutions were found in the two animals. 4. When 0.05 M NaCl was added to HCl solutions, an enhancing effect was found in the bullfrog, while a reducing effect occurred in the carp. On the contrary, when 0.05 M NaCl was added to NaOH solutions, an enhancing effect occurred in the carp, while no consistent result was founding the bullfrog. 5. Many amino acids were effective stimuli in the bullfrog, but only betaine and 1-aspartic acid were found effective in the carp. 6. Changes in temperatures beyond 35 degrees C or under 10 degrees C elicited responses. Mechanical stimuli were effective in the carp, but not in the bullfrog. 7. The "water response" was found in the bullfrog, but not in the carp. 8. Sensitivities of the olfactory epithelia of the two animals were compared and discussed. PMID:308564

  5. Neurogenetic approaches to habituation and dishabituation in Drosophila.

    PubMed

    Engel, Jeff E; Wu, Chun-Fang

    2009-09-01

    We review work in the major model systems for habituation in Drosophila melanogaster, encompassing several sensory modalities and behavioral contexts: visual (giant fiber escape response, landing response); chemical (proboscis extension reflex, olfactory jump response, locomotory startle response, odor-induced leg response, experience-dependent courtship modification); electric (shock avoidance); and mechanical (leg resistance reflex, cleaning reflex). Each model system shows several of Thompson and Spencer's [Thompson, R. F., & Spencer, W. A. (1966). Habituation: A model phenomenon for the study of neuronal substrates of behavior. Psychological Review, 73, 16-43] parametric criteria for habituation: spontaneous recovery and dishabituation have been described in almost all of them and dependence of habituation upon stimulus frequency and stimulus intensity in the majority. Stimulus generalization (and conversely, the delineation of stimulus specificity) has given insights into the localization of habituation or the neural architecture underlying sensory processing. The strength of Drosophila for studying habituation is the range of genetic approaches available. Mutations have been used to modify specific neuroanatomical structures, ion channels, elements of synaptic transmission, and second-messenger pathways. rutabaga and dunce, genes of the cAMP signal pathway that have been studied most often in the reviewed experiments, have also been implicated in synaptic plasticity and associative conditioning in Drosophila and other species including mammals. The use of the Gal4/UAS system for targeting gene expression has enabled genetic perturbation of defined sets of neurons. One clear lesson is that a gene may affect habituation differently in different behaviors, depending on the expression, processing, and localization of the gene product in specific circuits. Mutations of specific genes not only provide links between physiology and behavior in the same circuit, but

  6. Predicting Later IQ from Infant Visual Habituation and Dishabituation: A Meta-Analysis

    ERIC Educational Resources Information Center

    Kavsek, Michael

    2004-01-01

    The present meta-analysis of the predictive validity of visual habituation and visual dishabituation shows that the weighted and normalized average correlation between infant habituation/dishabituation and childhood cognitive performance is 0.37. In contrast to the findings of earlier reviews, for risk samples, dishabituation is apparently…

  7. Visual Habituation and Dishabituation in Preterm Infants: A Review and Meta-Analysis

    ERIC Educational Resources Information Center

    Kavsek, Michael; Bornstein, Marc H.

    2010-01-01

    We review comparative studies of infant habituation and dishabituation performance focusing on preterm infants. Habituation refers to cognitive encoding, and dishabituation refers to discrimination and memory. If habituation and dishabituation constitute basic information-processing skills, and preterm infants suffer cognitive disadvantages, then…

  8. Involvement of Subcortical Brain Structures During Olfactory Stimulation in Multiple Chemical Sensitivity.

    PubMed

    Alessandrini, Marco; Micarelli, Alessandro; Chiaravalloti, Agostino; Bruno, Ernesto; Danieli, Roberta; Pierantozzi, Mariangela; Genovesi, Giuseppe; Öberg, Johanna; Pagani, Marco; Schillaci, Orazio

    2016-03-01

    Multiple chemical sensitivity (MCS) patients usually react to odour compounds and the majority of neuroimaging studies assessed, especially at the cortical level, many olfactory-related correlates. The purpose of the present study was to depict sub-cortical metabolic changes during a neutral (NC) and pure (OC) olfactory stimulation by using a recently validated (18)F-2-fluoro-2-deoxy-D-glucose (FDG)-positron emission tomography/computer tomography procedure in 26 MCS and 11 healthy (HC) resting subjects undergoing a battery of clinical tests. Twelve subcortical volumes of interest were identified by the automated anatomical labeling library and normalized to thalamus FDG uptake. In both groups, when comparing OC to NC, the within-subjects ANOVA demonstrated a relative decreased metabolism in bilateral putamen and hippocampus and a relative increased metabolism in bilateral amygdala, olfactory cortex (OLF), caudate and pallidum. The between-groups ANOVA demonstrated in MCS a significant higher metabolism in bilateral OLF during NC. As in HC subjects negative correlations were found in OC between FDG uptake in bilateral amygdala and hippocampus and odor pleasantness scale, the latter positively correlated with MCS subjects' bilateral putamen FDG uptake in OC. Besides FDG uptake resemblances in both groups were found, for the first time a relative higher metabolism increase in OLF in MCS subjects at rest with respect to HC was found. When merging this aspect to the different subcortical FDG uptake correlations patterns in the two groups, the present study demonstrated to describe a peculiar metabolic index of behavioral and neurological aspects of MCS complaints. PMID:26438099

  9. Temporal patterns and selectivity in the unitary responses of olfactory receptors in the tiger salamander to odor stimulation.

    PubMed

    Baylin, F

    1979-07-01

    Temporal patterns and selectivity in unitary responses of 100 single olfactory receptors in the tiger salamander to odor stimulation were investigated. An olfactometer which permitted control of stimulus concentration, duration, and flow rate was calibrated with a gas chromatograph. Stimulus pulses were monitored by recording the electroolfactogram from the surface of the olfactory epithelium. Both diphasic and triphasic spikes were recorded extracellularly. No discernible differences in types of responses, reproducibility of responses, and cross-unit distribution of spontaneous rates distinguished diphasic from triphasic units. The cross-unit selectivity in responses to the seven olfactory stimulants used and the range of odorant concentrations which effectively evoked these responses suggest variations in types and number of types of receptive sites on each cell. Temporal patterns in the unitary responses were generally less complex than those observed in the olfactory bulb. Phasic stimulations evoked phasic patterns. Tonic stimulations evoked phasic/tonic patterns. Occasionally poststimulus depressions or elevations in firing rates were observed. The nature of these patterns varied somewhat with odorant concentration for a particular unit. PMID:479819

  10. Subconscious olfactory influences of stimulant and relaxant odors on immune function.

    PubMed

    Trellakis, Sokratis; Fischer, Cornelia; Rydleuskaya, Alena; Tagay, Sefik; Bruderek, Kirsten; Greve, Jens; Lang, Stephan; Brandau, Sven

    2012-08-01

    Brain and immune system are linked by bidirectional pathways so that changes of the central nervous system may influence various immune functions. The olfactory system may be involved in this interaction. In most odor studies subjects are aware of an odor exposure, using frequently high odor concentrations or long-term exposures without controls. In this pilot study, the potential immune effects of short-term odor exposure were examined in 32 blinded subjects (16 male, 16 female). Subjects were exposed without their knowledge either to a stimulant essential oil (grapefruit, fennel, pepper), a no-odor control or a relaxant essential oil (lavender, patchouli, rose) during a set of psychological questionnaires for 30 min at three separate visits. Activity of neutrophil granulocytes (CXCL8 release, CD16) and peripheral blood concentrations of mainly neutrophil-related immunological markers were measured. We tested the triple of stimulant odor, control and relaxant odor for every subject in a model which assumed opposite effects of the stimulant and the relaxant odor. This hypothesis was falsified by our experimental data, as no significant effect was observed for the parameters tested. The human immune functions tested in our study are not modulated by short-term odor exposure in blinded subjects. Further studies should directly dissect possible differences between long-term and short-term exposures of non-blinded subjects versus blinded subjects. PMID:22159968

  11. 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

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

    PubMed

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

    2016-03-01

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

  13. 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. PMID:22261746

  14. Allocation of attentional resources during habituation and dishabituation of male sexual arousal.

    PubMed

    Koukounas, E; Over, R

    1999-12-01

    A secondary-task probe (tone) was presented intermittently while men viewed erotic film segments across a session involving 18 trials with the same film segment (habituation), then 2 trials with different film segments (novelty) and 2 trials with reinstatement of the original segment (dishabituation). Reaction time to the tone (an index of the extent processing resources were being committed to the erotic stimulus) shifted during the session in parallel with changes that occurred in penile tumescence and subjective sexual arousal. The decrease in sexual arousal over the first 18 trials in the session was accompanied by a progressively faster reaction to the tone, novel stimulation led to recovery of sexual arousal and a slower reaction to the tone, and on trials 21 and 22 sexual arousal and reaction time levels were above the values that prevailed immediately prior to novel stimulation. Results are discussed with reference to the relationship between habituation and attention. PMID:10650440

  15. Tactile roughness perception in the presence of olfactory and trigeminal stimulants

    PubMed Central

    Koijck, Lara A.; Van Erp, Jan B.F.

    2015-01-01

    Previous research has shown that odorants consistently evoke associations with textures and their tactile properties like smoothness and roughness. Also, it has been observed that olfaction can modulate tactile perception. We therefore hypothesized that tactile roughness perception may be biased towards the somatosensory connotation of an ambient odorant. We performed two experiments to test this hypothesis. In the first experiment, we investigated the influence of ambient chemosensory stimuli with different roughness connotations on tactile roughness perception. In addition to a pleasant odor with a connotation of softness (PEA), we also included a trigeminal stimulant with a rough, sharp or prickly connotation (Ethanol). We expected that—compared to a No-odorant control condition—tactile texture perception would be biased towards smoothness in the presence of PEA and towards roughness in the presence of Ethanol. However, our results show no significant interaction between chemosensory stimulation and perceived tactile surface roughness. It could be argued that ambient odors may be less effective in stimulating crossmodal associations, since they are by definition extraneous to the tactile stimuli. In an attempt to optimize the conditions for sensory integration, we therefore performed a second experiment in which the olfactory and tactile stimuli were presented in synchrony and in close spatial proximity. In addition, we included pleasant (Lemon) and unpleasant (Indole) odorants that are known to have the ability to affect tactile perception. We expected that tactile stimuli would be perceived as less rough when simultaneously presented with Lemon or PEA (both associated with softness) than when presented with Ethanol or Indole (odors that can be associated with roughness). Again, we found no significant main effect of chemosensory condition on perceived tactile roughness. We discuss the limitations of this study and we present suggestions for future research

  16. Effects of olfactory stimulation with jasmin and its component chemicals on the duration of pentobarbital-induced sleep in mice.

    PubMed

    Tsuchiya, T; Tanida, M; Uenoyama, S; Nakayama, Y

    1992-01-01

    The effect of olfactory stimulation with jasmin and its component chemicals on pentobarbital sleep time was investigated using mice. In the present study we sought to determine which component of jasmin influences pentobarbital sleep time via olfactory stimulation. Sleep time was defined as the time elapsed between intraperitoneal pentobarbital administration and the first time that the animal was able to spontaneously right itself. Sleep time was significantly decreased by olfactory stimulation with jasmin, and also by one of the fractions obtained by fractional distillation at 150 degrees C and 0.1 mmHg. The fraction which influenced the sleep time was found to consist of benzyl benzoate, isophytol, geranyl linalool, phytol and phytyl acetate, which were identified using gas chromatography with mass and infrared spectrometry. In experiments using authentic samples of these components, phytol significantly shortened the pentobarbital sleep time, while the others had no effect. We conclude that phytol is the component of jasmin which reduces the duration of pentobarbital-induced sleep. PMID:1556904

  17. 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

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

    PubMed

    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

  19. Dishabituation of the BOLD response to speech sounds

    PubMed Central

    Zevin, Jason D; McCandliss, Bruce D

    2005-01-01

    Background Neural systems show habituation responses at multiple levels, including relatively abstract language categories. Dishabituation – responses to non-habituated stimuli – can provide a window into the structure of these categories, without requiring an overt task. Methods We used an event-related fMRI design with short interval habituation trials, in which trains of stimuli were presented passively during 1.5 second intervals of relative silence between clustered scans. Trains of four identical stimuli (standard trials) and trains of three identical stimuli followed by a stimulus from a different phonetic category (deviant trials) were presented. This paradigm allowed us to measure and compare the time course of overall responses to speech, and responses to phonetic change. Results Comparisons between responses to speech and silence revealed strong responses throughout the extent of superior temporal gyrus (STG) bilaterally. Comparisons between deviant and standard trials revealed dishabituation responses in a restricted region of left posterior STG, near the border with supramarginal gyrus (SMG). Novelty responses to deviant trials were also observed in right frontal regions and hippocampus. Conclusion A passive, dishabituation paradigm provides results similar to studies requiring overt responses. This paradigm can readily be extended for the study of pre-attentive processing of speech in populations such as children and second-language learners whose overt behavior is often difficult to interpret because of ancillary task demands. PMID:15953396

  20. 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…

  1. Differential potentiation of early and late components evoked in olfactory cortex by stimulation of cortical association fibers.

    PubMed

    Stripling, Jeffrey S; Galupo, M Paz

    2008-12-30

    The present study examined in detail the development and decay of potentiation induced in vivo by repeated high-frequency stimulation of cortical association fibers (AF) in piriform cortex (PC). Male Long-Evans rats with chronically-implanted stimulating and recording electrodes were administered potentiating AF stimulation (thirty 10-pulse 100-Hz trains) on 8 consecutive days, followed by a ninth administration after an 8-day layoff. The time course of potentiation was monitored by local field potentials evoked in the PC and olfactory bulb (OB) by 0.1 Hz single-pulse AF test stimulation before, during, and following each potentiating treatment. AF test stimulation evoked two distinct components in the PC, an early component (EC) and a late component (LC). High-frequency AF stimulation produced potentiation of each component, but with very different characteristics. EC potentiation consisted of a brief augmentation during each bout of potentiating stimulation that persisted <2 min after the last high-frequency train and showed no cumulative effects following repeated induction across days. In contrast, LC potentiation developed gradually, requiring several daily potentiation treatments to reach maximum amplitude, and decayed more slowly each time it was induced. Furthermore, LC potentiation persisted in latent form for at least 8 days following its apparent decay and could be reinstated by repeated test stimulation that was without effect at the beginning of the experiment. Potentiation in the OB resembled LC potentiation in its characteristics, but with less latent potentiation. These results indicate that the potentiation reported here is distinctly different from the long-term potentiation previously demonstrated in vitro in the PC, and suggest that this potentiation represents an increase in excitability within the cortical association fiber system that can be stored in latent form and retrieved at a later time. These characteristics make this potentiation a

  2. Olfactory stimulation selectively modulates the OFF pathway in the retina of zebrafish.

    PubMed

    Esposti, Federico; Johnston, Jamie; Rosa, Juliana M; Leung, Kin-Mei; Lagnado, Leon

    2013-07-10

    Cross-modal regulation of visual performance by olfactory stimuli begins in the retina, where dopaminergic interneurons receive projections from the olfactory bulb. However, we do not understand how olfactory stimuli alter the processing of visual signals within the retina. We investigated this question by in vivo imaging activity in transgenic zebrafish expressing SyGCaMP2 in bipolar cell terminals and GCaMP3.5 in ganglion cells. The food-related amino acid methionine reduced the gain and increased sensitivity of responses to luminance and contrast transmitted through OFF bipolar cells but not ON. The effects of olfactory stimulus were blocked by inhibiting dopamine uptake and release. Activation of dopamine receptors increased the gain of synaptic transmission in vivo and potentiated synaptic calcium currents in isolated bipolar cells. These results indicate that olfactory stimuli alter the sensitivity of the retina through the dopaminergic regulation of presynaptic calcium channels that control the gain of synaptic transmission through OFF bipolar cells. PMID:23849198

  3. Spatial distribution of neural activity in the anterior olfactory nucleus evoked by odor and electrical stimulation

    PubMed Central

    KAY, RACHEL B.; MEYER, ELIZABETH AMORY; ILLIG, KURT R.; BRUNJES, PETE C.

    2012-01-01

    Several lines of evidence indicate that complex odorant stimuli are parsed into separate data streams in the glomeruli of the olfactory bulb, yielding a combinatorial “odotopic map.” However, this pattern does not appear to be maintained in the piriform cortex, where stimuli appear to be coded in a distributed fashion. The anterior olfactory nucleus (AON) is intermediate and reciprocally interconnected between these two structures, and also provides a route for the interhemispheric transfer of olfactory information. The present study examined potential coding strategies used by the AON. Rats were exposed to either caproic acid, butyric acid, limonene, or purified air and the spatial distribution of Fos-immunolabeled cells was quantified. The two major subregions of the AON exhibited different results. Distinct odor-specific spatial patterns of activity were observed in pars externa, suggesting that it employs a topographic strategy for odor representation similar to the olfactory bulb. A spatially distributed pattern that did not appear to depend on odor identity was observed in pars principalis, suggesting that it employs a distributed representation of odors more similar to that seen in the piriform cortex. PMID:21165975

  4. Dynamics of olfactory bulb input and output activity during odor stimulation in zebrafish.

    PubMed

    Friedrich, Rainer W; Laurent, Gilles

    2004-06-01

    The processing of odor-evoked activity in the olfactory bulb (OB) of zebrafish was studied by extracellular single unit recordings from the input and output neurons, i.e., olfactory receptor neurons (ORNs) and mitral cells (MCs), respectively. A panel of 16 natural amino acid odors was used as stimuli. Responses of MCs, but not ORNs, changed profoundly during the first few hundred milliseconds after response onset. In MCs, but not ORNs, the total evoked excitatory activity in the population was initially odor-dependent but subsequently converged to a common level. Hence, the overall population activity is regulated by network interactions in the OB. The tuning widths of both ORN and MC response profiles were similar and, on average, stable over time. However, when analyzed for individual neurons, MC response profiles could sharpen (excitatory response to fewer odors) or broaden (excitatory response to more odors), whereas ORN response profiles remained nearly unchanged. Several observations indicate that dynamic inhibition plays an important role in this remodeling. Finally, the reliability of odor identification based on MC population activity patterns improved over time, whereas odor identification based on ORN activity patterns was most reliable early in the odor response. These results demonstrate that several properties of MC, but not ORN, activity change during the initial phase of the odor response with important consequences for odor-encoding activity patterns. Furthermore, our data indicate that inhibitory interactions in the OB are important in dynamically shaping the activity of OB output neurons. PMID:14960561

  5. Changes in Cerebral Blood Flow during Olfactory Stimulation in Patients with Multiple Chemical Sensitivity: A Multi-Channel Near-Infrared Spectroscopic Study

    PubMed Central

    Azuma, Kenichi; Uchiyama, Iwao; Takano, Hirohisa; Tanigawa, Mari; Azuma, Michiyo; Bamba, Ikuko; Yoshikawa, Toshikazu

    2013-01-01

    Multiple chemical sensitivity (MCS) is characterized by somatic distress upon exposure to odors. Patients with MCS process odors differently from controls. This odor-processing may be associated with activation in the prefrontal area connecting to the anterior cingulate cortex, which has been suggested as an area of odorant-related activation in MCS patients. In this study, activation was defined as a significant increase in regional cerebral blood flow (rCBF) because of odorant stimulation. Using the well-designed card-type olfactory test kit, changes in rCBF in the prefrontal cortex (PFC) were investigated after olfactory stimulation with several different odorants. Near-infrared spectroscopic (NIRS) imaging was performed in 12 MCS patients and 11 controls. The olfactory stimulation test was continuously repeated 10 times. The study also included subjective assessment of physical and psychological status and the perception of irritating and hedonic odors. Significant changes in rCBF were observed in the PFC of MCS patients on both the right and left sides, as distinct from the center of the PFC, compared with controls. MCS patients adequately distinguished the non-odorant in 10 odor repetitions during the early stage of the olfactory stimulation test, but not in the late stage. In comparison to controls, autonomic perception and negative affectivity were poorer in MCS patients. These results suggest that prefrontal information processing associated with odor-processing neuronal circuits and memory and cognition processes from past experience of chemical exposure play significant roles in the pathology of this disorder. PMID:24278291

  6. Anxiolytic-like effect of inhalation of essential oil from Lavandula officinalis: investigation of changes in 5-HT turnover and involvement of olfactory stimulation.

    PubMed

    Takahashi, Mizuho; Yamanaka, Ayako; Asanuma, Chihiro; Asano, Hiroko; Satou, Tadaaki; Koike, Kazuo

    2014-07-01

    Essential oil extracted from Lavandula officinalis (LvEO) has a long history of usage in anxiety alleviation with good evidence to support its use. However, findings and information regarding the exact pathway involved and mechanism of action remain inconclusive. Therefore, we aimed to (1) reveal the influence of olfactory stimulation, and (2) determine whether the serotonergic system is involved in the anxiolytic effect of LvEO when it is inhaled. To this end, we first compared the anxiety-related behaviors of normosmic and anosmic mice. LvEO inhalation caused notable elevation in anxiety-related parameters with or without olfactory perception, indicating that olfactory stimulation is not necessarily required for LvEO to be effective. Neurochemical analysis of the serotonin (5-HT) turnover rate, accompanied by EPM testing, was then performed. LvEO significantly increased the striatal and hippocampal levels of 5-HT and decreased turnover rates in accordance with the anxiolytic behavioral changes. These results, together with previous findings, support the hypothesis that serotonergic neurotransmission plays a certain role in the anxiolytic properties of LvEO. PMID:25230519

  7. Ca2+/calmodulin-mediated fast desensitization by the B1b subunit of the CNG channel affects response termination but not sensitivity to recurring stimulation in olfactory sensory neurons

    PubMed Central

    Song, Yijun; Cygnar, Katherine D.; Sagdullaev, Botir; Valley, Matthew; Hirsh, Sarah; Stephan, Aaron; Reisert, Johannes; Zhao, Haiqing

    2008-01-01

    Summary Ca2+/calmodulin-mediated negative feedback is a prototypical regulatory mechanism for Ca2+ permeable ion channels. In olfactory sensory neurons (OSNs) such regulation on the cyclic nucleotide-gated (CNG) channel is considered a major mechanism of OSN adaptation. To determine the role of Ca2+/calmodulin desensitization of the olfactory CNG channel, we introduced a mutation in the channel subunit CNGB1b in mice that rendered the channel resistant to fast desensitization by Ca2+/calmodulin. Contrary to expectations, mutant OSNs showed normal receptor current adaptation to repeated stimulation. Rather, they displayed slower response termination and consequently, a reduced ability to transmit olfactory information to the olfactory bulb. They also displayed reduced response decline during sustained odorant exposure. These results suggest that Ca2+/calmodulin-mediated CNG channel fast desensitization is less important in regulating the sensitivity to recurring stimulation than previously thought and instead functions primarily to terminate OSN responses. PMID:18466748

  8. Habituation and dishabituation during object play in kennel-housed dogs.

    PubMed

    Pullen, Anne J; Merrill, Ralph J N; Bradshaw, John W S

    2012-11-01

    Domestic dogs are reported to show intense but transient neophilia towards novel objects. Here, we examine habituation and dishabituation to manipulable objects by kennel-housed dogs. Labrador retrievers (N = 16) were repeatedly presented with one toy for successive 30-s periods until interaction ceased. At this point (habituation), a different toy was presented that contrasted with the first in both colour and odour (since the dog's saliva would have accumulated on the first), colour alone, or odour alone. No effect of the type of contrast was detected in the number of presentations to habituation, the difference in duration of interaction between the first presentation of the first toy and the presentation of the second toy (recovery), or the duration of interaction with the second toy (dishabituation). Varying the time interval between successive presentations of the first toy up to habituation between 10 s and 10 min had no effect on the number of presentations to habituation, nor did it alter the extent of dishabituation. Varying the delay from habituation to presentation of the second toy, between 10 s and 15 min, affected neither the recovery nor the dishabituation. Overall, the study indicates that loss of interest in the object during object-orientated play in this species is due to habituation to the overall stimulus properties of the toy rather than to any single sensory modality and is also atypical in its insensitivity to the interval between presentations. PMID:22825035

  9. 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. PMID:23614017

  10. Super-resolution imaging of ciliary microdomains in isolated olfactory sensory neurons using a custom two-color stimulated emission depletion microscope

    NASA Astrophysics Data System (ADS)

    Meyer, Stephanie A.; Ozbay, Baris N.; Potcoava, Mariana; Salcedo, Ernesto; Restrepo, Diego; Gibson, Emily A.

    2016-06-01

    We performed stimulated emission depletion (STED) imaging of isolated olfactory sensory neurons (OSNs) using a custom-built microscope. The STED microscope uses a single pulsed laser to excite two separate fluorophores, Atto 590 and Atto 647N. A gated timing circuit combined with temporal interleaving of the different color excitation/STED laser pulses filters the two channel detection and greatly minimizes crosstalk. We quantified the instrument resolution to be ˜81 and ˜44 nm, for the Atto 590 and Atto 647N channels. The spatial separation between the two channels was measured to be under 10 nm, well below the resolution limit. The custom-STED microscope is incorporated onto a commercial research microscope allowing brightfield, differential interference contrast, and epifluorescence imaging on the same field of view. We performed immunolabeling of OSNs in mice to image localization of ciliary membrane proteins involved in olfactory transduction. We imaged Ca2+-permeable cyclic nucleotide gated (CNG) channel (Atto 594) and adenylyl cyclase type III (ACIII) (Atto 647N) in distinct cilia. STED imaging resolved well-separated subdiffraction limited clusters for each protein. We quantified the size of each cluster to have a mean value of 88±48 nm and 124±43 nm, for CNG and ACIII, respectively. STED imaging showed separated clusters that were not resolvable in confocal images.

  11. Sexual Stimulation Increases the Survival of New Cells in the Accessory Olfactory Bulb of the Male Rat

    PubMed Central

    Unda, Nancy M.; Portillo, Wendy; Corona, Rebeca; Paredes, Raúl G.

    2016-01-01

    Sexual behavior in rodents is modulated by the olfactory system. The olfactory bulb (OB) is a structure that undergoes continues neurogenesis in adulthood. We have previously shown that 15 days after males rats pace the sexual interaction and ejaculate 1 or 3 times, there is an increase in the density of new cells that reach the accessory olfactory bulb (AOB). The aim of the present study was to evaluate if sexual behavior in male rats increases the density of new neurons that survive 45 days after sexual behavior in the AOB and in the main OB (MOB). Male rats were randomly divided in four groups: (1) Control (Ctr), males without sexual interaction; (2) Exposed (Exp), males only exposed to a sexually receptive female; (3) No pacing (NP), males that mated in conditions in which the female paced the sexual interaction; (4) One ejaculation (1E), males that paced the sexual interaction with a receptive female and ejaculated once; and (5) Three ejaculations (3E), males that paced the sexual interaction and were allowed to ejaculate three times. All males were injected with the DNA synthesis marker 5-bromo-2-deoxyuridine (BrdU), and were tested in one of the above conditions. 45 days later they were sacrificed, and the OBs were processed to identify new cells and evaluate if they had differentiated into neurons. Our data indicate that males that ejaculated three times showed an increase in the density of new cells that survive in the posterior part of the granular cell layer of the AOB and have more new neurons that the control group. However, no significant differences were found in the percentage of new cells that differentiate into neurons. No significant increase in the density of new cells was observed in the MOB. Our data show that pacing the sexual interaction until three ejaculations increases the density of new cells and neurons in the granular layer of the AOB, confirming that sexual behavior induces long-lasting plastic changes in the OB. PMID:26973447

  12. Sexual Stimulation Increases the Survival of New Cells in the Accessory Olfactory Bulb of the Male Rat.

    PubMed

    Unda, Nancy M; Portillo, Wendy; Corona, Rebeca; Paredes, Raúl G

    2016-01-01

    Sexual behavior in rodents is modulated by the olfactory system. The olfactory bulb (OB) is a structure that undergoes continues neurogenesis in adulthood. We have previously shown that 15 days after males rats pace the sexual interaction and ejaculate 1 or 3 times, there is an increase in the density of new cells that reach the accessory olfactory bulb (AOB). The aim of the present study was to evaluate if sexual behavior in male rats increases the density of new neurons that survive 45 days after sexual behavior in the AOB and in the main OB (MOB). Male rats were randomly divided in four groups: (1) Control (Ctr), males without sexual interaction; (2) Exposed (Exp), males only exposed to a sexually receptive female; (3) No pacing (NP), males that mated in conditions in which the female paced the sexual interaction; (4) One ejaculation (1E), males that paced the sexual interaction with a receptive female and ejaculated once; and (5) Three ejaculations (3E), males that paced the sexual interaction and were allowed to ejaculate three times. All males were injected with the DNA synthesis marker 5-bromo-2-deoxyuridine (BrdU), and were tested in one of the above conditions. 45 days later they were sacrificed, and the OBs were processed to identify new cells and evaluate if they had differentiated into neurons. Our data indicate that males that ejaculated three times showed an increase in the density of new cells that survive in the posterior part of the granular cell layer of the AOB and have more new neurons that the control group. However, no significant differences were found in the percentage of new cells that differentiate into neurons. No significant increase in the density of new cells was observed in the MOB. Our data show that pacing the sexual interaction until three ejaculations increases the density of new cells and neurons in the granular layer of the AOB, confirming that sexual behavior induces long-lasting plastic changes in the OB. PMID:26973447

  13. Neural network simulation of habituation and dishabituation in infant speech perception

    NASA Astrophysics Data System (ADS)

    Gauthier, Bruno; Shi, Rushen; Proulx, Robert

    2001-05-01

    The habituation techniques used in infant speech perception studies are based on the fact that infants show renewed interest towards novel stimuli. Recent work has shown the possibility of using artificial neural networks to model habituation and dishabituation (e.g., Schafer and Mareschal, 2001). In our study we examine weather the self-organizing-feature-maps (SOM) (Kohonen, 1989) are appropriate for modeling short-term habituation to a repeated speech stimulus. We found that although SOMs are particularly useful for simulating categorization, they can be modified to model habituation and dishabituation, so that they can be applied to direct comparisons with behavioral data on infants' speech discrimination abilities. In particular, we modified the SOMs to include additional parameters that control the relation of input similarity, lateral inhibition, and local and lateral activation between neurons. Preliminary results suggest that these parameters are sufficient for the network to simulate the loss of sensitivity of the auditory system due to the presentation of multiple tokens of a speech stimulus, as well as to model the recovery of sensitivity to a novel stimulus. The implications of this approach to infant speech perception research will be considered.

  14. Olfactory Receptor Neuron Dysfunction in Schizophrenia

    PubMed Central

    Turetsky, Bruce I; Hahn, Chang-Gyu; Arnold, Steven E; Moberg, Paul J

    2012-01-01

    Olfactory impairments are a common feature of schizophrenia. Impairments in odor detection and odor identification are present early in the course of illness and among those at risk for the disorder. These behavioral impairments have been linked to both physiological and anatomical abnormalities in the neural substrates subserving olfaction, including relatively peripheral elements of the olfactory system. The location of olfactory receptor neurons in the nasal epithelium allows noninvasive access to these neurons in living subjects. This offers a unique opportunity to directly assess neuronal integrity in vivo in patients. The peripheral olfactory receptor neuron response to odor stimulation was assessed in 21 schizophrenia patients and 18 healthy comparison subjects. The electroolfactogram, representing the electrical depolarization of the olfactory receptor neurons, was recording following stimulation with different doses and durations of hydrogen sulfide, a pure olfactory nerve stimulant. Schizophrenia patients had abnormally large depolarization responses following odor stimulation, independent of clinical symptomatology, antipsychotic medication dosage or smoking history. Although the precise pathophysiological mechanism is unknown, this olfactory receptor neuron abnormality is consistent with several lines of evidence suggesting altered proliferation or maturation of olfactory receptor neuron cell lineages in schizophrenia. It is also consistent with emerging evidence of disruptions of cyclic AMP-mediated intracellular signaling mechanisms, and may be a marker of these disruptions. It unambiguously demonstrates that neurophysiological disturbances in schizophrenia are not limited to cortical and subcortical structures, but rather include even the most peripheral sensory neurons. PMID:18754006

  15. Olfactory receptor neuron dysfunction in schizophrenia.

    PubMed

    Turetsky, Bruce I; Hahn, Chang-Gyu; Arnold, Steven E; Moberg, Paul J

    2009-02-01

    Olfactory impairments are a common feature of schizophrenia. Impairments in odor detection and odor identification are present early in the course of illness and among those at risk for the disorder. These behavioral impairments have been linked to both physiological and anatomical abnormalities in the neural substrates subserving olfaction, including relatively peripheral elements of the olfactory system. The location of olfactory receptor neurons in the nasal epithelium allows noninvasive access to these neurons in living subjects. This offers a unique opportunity to directly assess neuronal integrity in vivo in patients. The peripheral olfactory receptor neuron response to odor stimulation was assessed in 21 schizophrenia patients and 18 healthy comparison subjects. The electroolfactogram, representing the electrical depolarization of the olfactory receptor neurons, was recording following stimulation with different doses and durations of hydrogen sulfide, a pure olfactory nerve stimulant. Schizophrenia patients had abnormally large depolarization responses following odor stimulation, independent of clinical symptomatology, antipsychotic medication dosage or smoking history. Although the precise pathophysiological mechanism is unknown, this olfactory receptor neuron abnormality is consistent with several lines of evidence suggesting altered proliferation or maturation of olfactory receptor neuron cell lineages in schizophrenia. It is also consistent with emerging evidence of disruptions of cyclic AMP-mediated intracellular signaling mechanisms, and may be a marker of these disruptions. It unambiguously demonstrates that neurophysiological disturbances in schizophrenia are not limited to cortical and subcortical structures, but rather include even the most peripheral sensory neurons. PMID:18754006

  16. 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…

  17. An endocannabinoid system is present in the mouse olfactory epithelium but does not modulate olfaction

    PubMed Central

    Hutch, Chelsea; Hillard, Cecilia J.; Jia, Cuihong; Hegg, Colleen C.

    2015-01-01

    Endocannabinoids modulate a diverse array of functions including progenitor cell proliferation in the central nervous system, and odorant detection and food intake in the mammalian central olfactory system and larval Xenopus laevis peripheral olfactory system. However, the presence and role of endocannabinoids in the peripheral olfactory epithelium has not been examined in mammals. We found the presence of cannabinoid type 1 (CB1) and cannabinoid type 2 (CB2) receptor protein and mRNA in the olfactory epithelium. Using either immunohistochemistry or calcium imaging we localized CB1 receptors on neurons, glia like sustentacular cells, microvillous cells and progenitor-like basal cells. To examine the role of endocannabinoids, CB1 and CB2 receptor deficient (CB1−/−/CB2−/−) mice were used. The endocannabinoid 2-arachidonylglycerol (2-AG) was present at high levels in both C57BL/6 wildtype and CB1−/−/CB2−/− mice. 2-AG synthetic and degradative enzymes are expressed in wildtype mice. A small but significant decrease in basal cell and olfactory sensory neuron numbers was observed in CB1−/−/CB2−/− mice compared to wildtype mice. The decrease in olfactory sensory neurons did not translate to impairment in olfactory-mediated behaviors assessed by the buried food test and habituation/dishabituation test. Collectively, these data indicate the presence of an endocannabinoid system in the mouse olfactory epithelium. However, unlike in tadpoles, endocannabinoids do not modulate olfaction. Further investigation on the role of endocannabinoids in progenitor cell function in the olfactory epithelium is warranted. PMID:26037800

  18. 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

  19. 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.

  20. Protein kinase C sensitizes olfactory adenylate cyclase.

    PubMed

    Frings, S

    1993-02-01

    Effects of neurotransmitters on cAMP-mediated signal transduction in frog olfactory receptor cells (ORCs) were studied using in situ spike recordings and radioimmunoassays. Carbachol, applied to the mucosal side of olfactory epithelium, amplified the electrical response of ORCs to cAMP-generating odorants, but did not affect unstimulated cells. A similar augmentation of odorant response was observed in the presence of phorbol dibutyrate (PDBu), an activator of protein kinase C (PKC). The electrical response to forskolin, an activator of adenylate cyclase (AC), was also enhanced by PDBu, and it was attenuated by the PKC inhibitor Goe 6983. Forskolin-induced accumulation of cAMP in olfactory tissue was potentiated by carbachol, serotonin, and PDBu to a similar extent. Potentiation was completely suppressed by the PKC inhibitors Goe 6983, staurosporine, and polymyxin B, suggesting that the sensitivity of olfactory AC to stimulation by odorants and forskolin was increased by PKC. Experiments with deciliated olfactory tissue indicated that sensitization of AC was restricted to sensory cilia of ORCs. To study the effects of cell Ca2+ on these mechanisms, the intracellular Ca2+ concentration of olfactory tissue was either increased by ionomycin or decreased by BAPTA/AM. Increasing cell Ca2+ had two effects on cAMP production: (a) the basal cAMP production was enhanced by a mechanism sensitive to inhibitors of calmodulin; and (b) similar to phorbol ester, cell Ca2+ caused sensitization of AC to stimulation by forskolin, an effect sensitive to Goe 6983. Decreasing cell Ca2+ below basal levels rendered AC unresponsive to stimulation by forskolin. These data suggest that a crosstalk mechanism is functional in frog ORCs, linking the sensitivity of AC to the activity of PKC. At increased activity of PKC, olfactory AC becomes more responsive to stimulation by odorants, forskolin, and cell Ca2+. Neurotransmitters appear to use this crosstalk mechanism to regulate olfactory

  1. DIFFERENT MECHANISMS ARE RESPONSIBLE FOR DISHABITUATION OF ELECTROPHYSIOLOGICAL AUDITORY RESPONSES TO A CHANGE IN ACOUSTIC IDENTITY THAN TO A CHANGE IN STIMULUS LOCATION

    PubMed Central

    Smulders, Tom V.; Jarvis, Erich D.

    2014-01-01

    Repeated exposure to an auditory stimulus leads to habituation of the electrophysiological and immediate-early-gene (IEG) expression response in the auditory system. A novel auditory stimulus reinstates this response in a form of dishabituation. This has been interpreted as the start of new memory formation for this novel stimulus. Changes in the location of an otherwise identical auditory stimulus can also dishabituate the IEG expression response. This has been interpreted as an integration of stimulus identity and stimulus location into a single auditory object, encoded in the firing patterns of the auditory system. In this study, we further tested this hypothesis. Using chronic multi-electrode arrays to record multi-unit activity from the auditory system of awake and behaving zebra finches, we found that habituation occurs to repeated exposure to the same song and dishabituation with a novel song, similar to that described in head-fixed, restrained animals. A large proportion of recording sites also showed dishabituation when the same auditory stimulus was moved to a novel location. However, when the song was randomly moved among 8 interleaved locations, habituation occurred independently of the continuous changes in location. In contrast, when 8 different auditory stimuli were interleaved all from the same location, a separate habituation occurred to each stimulus. This result suggests that neuronal memories of the acoustic identity and spatial location are different, and that allocentric location of a stimulus is not encoded as part of the memory for an auditory object, while its acoustic properties are. We speculate that, instead, the dishabituation that occurs with a change from a stable location of a sound is due to the unexpectedness of the location change, and might be due to different underlying mechanisms than the dishabituation and separate habituations to different acoustic stimuli. PMID:23999220

  2. Effects of handedness on olfactory event-related potentials in a simple olfactory task.

    PubMed

    Gottschlich, Marie; Hummel, Thomas

    2015-06-01

    The purpose of the present study was to re-investigate the influence of handedness on simple olfactory tasks to further clarify the role of handedness in chemical senses. Similar to language and other sensory systems, effects of handedness should be expected. Young, healthy subjects participated in this study, including 24 left-handers and 24 right-handers, with no indication of any major nasal or health problems. The two groups did not differ in terms of sex and age (14 women and 10 men in each group). They had a mean age of 24.0 years. Olfactory event-related potentials were recorded after left or right olfactory stimulation with the rose-like odor phenyl ethyl alcohol (PEA) or the smell of rotten eggs (hydrogen sulfide, H2S). Results suggested that handedness has no major influence on amplitude or latency of olfactory event-related potentials when it comes to simple olfactory tasks. PMID:26030037

  3. Odor stimuli trigger influx of calcium into olfactory neurons of the channel catfish.

    PubMed

    Restrepo, D; Miyamoto, T; Bryant, B P; Teeter, J H

    1990-09-01

    Olfactory transduction is thought to be mediated by a G protein-coupled increase in intracellular adenosine 3',5'-monophosphate (cAMP) that triggers the opening of cAMP-gated cation channels and results in depolarization of the plasma membrane of olfactory neurons. In olfactory neurons isolated from the channel catfish, Ictalurus punctatus, stimulation with olfactory stimuli (amino acids) elicits an influx of calcium that leads to a rapid increase in intracellular calcium. In addition, in a reconstitution assay a plasma membrane calcium channel has been identified that is gated by inositol-1,4,5-trisphosphate (IP3), which could mediate this calcium influx. Together with previous studies indicating that stimulation with olfactory stimuli leads to stimulation of phosphoinositide turnover in olfactory cilia, these data suggest that an influx of calcium triggered by odor stimulation of phosphoinositide turnover may be an alternate or additional mechanism of olfactory transduction. PMID:2168580

  4. Human olfactory lateralization requires trigeminal activation.

    PubMed

    Croy, Ilona; Schulz, Max; Blumrich, Anna; Hummel, Cornelia; Gerber, Johannes; Hummel, Thomas

    2014-09-01

    Rats are able to lateralize odors. This ability involves specialized neurons in the orbitofrontal cortex which are able to process the left, right and bilateral presentation of stimuli. However, it is not clear whether this function is preserved in humans. Humans are in general not able to differentiate whether a selective olfactory stimulant has been applied to the left or right nostril; however exceptions have been reported. Following a screening of 152 individuals with an olfactory lateralization test, we identified 19 who could lateralize odors above chance level. 15 of these "lateralizers" underwent olfactory fMRI scanning in a block design and were compared to 15 controls matched for age and sex distribution. As a result, both groups showed comparable activation of olfactory eloquent brain areas. However, subjects with lateralization ability had a significantly enhanced activation of cerebral trigeminal processing areas (somatosensory cortex, intraparietal sulcus). In contrast to controls, lateralizers furthermore exhibited no suppression in the area of the trigeminal principal sensory nucleus. An exploratory study with an olfactory change detection paradigm furthermore showed that lateralizers oriented faster towards changes in the olfactory environment. Taken together, our study suggests that the trigeminal system is activated to a higher degree by the odorous stimuli in the group of "lateralizers". We conclude that humans are not able to lateralize odors based on the olfactory input alone, but vary in the degree to which the trigeminal system is recruited. PMID:24825502

  5. Olfactory Classical Conditioning in Neonates

    PubMed Central

    Sullivan, Regina M.; Taborsky-Barba, Suzanne; Mendoza, Raffael; Itano, Alison; Leon, Michael; Cotman, Carl W.; Payne, Terrence F.; Lott, Ira

    2007-01-01

    One-day-old, awake infants underwent an olfactory classical conditioning procedure to assess associative learning within the olfactory system of newborns. Experimental infants received ten 30-second pairings of a novel olfactory conditioned stimulus (a citrus odor of neutral value) and tactile stimulation provided by stroking as the reinforcing unconditioned stimulus (a stimulus with positive properties). Control babies received only the odor, only the stroking, or the stroking followed by the odor presentation. The next day, all infants, in either the awake or sleep state, were given five 30-second presentations of the odor. Results were analyzed from video tapes scored by an observer unaware of the infants’ training condition. The results indicate that only those infants who received the forward pairings of the odor and stroking exhibited conditioned responding (head turning toward the odor) to the citrus odor. The performance of the conditioned response was not affected by the state of the baby during testing, because both awake and sleeping infants exhibited conditioned responses. Furthermore, the expression of the conditioned response was odor specific; a novel floral odor presented during testing did not elicit conditioned responses in the experimental babies. These results suggest that complex associative olfactory learning is seen in newborns within the first 48 hours of life. These baseline findings may serve as normative data against which observation from neonates at risk for neurological sequelae may be compared. PMID:2011429

  6. 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…

  7. Olfactory marker protein (OMP) gene deletion causes altered physiological activity of olfactory sensory neurons.

    PubMed Central

    Buiakova, O I; Baker, H; Scott, J W; Farbman, A; Kream, R; Grillo, M; Franzen, L; Richman, M; Davis, L M; Abbondanzo, S; Stewart, C L; Margolis, F L

    1996-01-01

    Olfactory marker protein (OMP) is an abundant, phylogentically conserved, cytoplasmic protein of unknown function expressed almost exclusively in mature olfactory sensory neurons. To address its function, we generated OMP-deficient mice by gene targeting in embryonic stem cells. We report that these OMP-null mice are compromised in their ability to respond to odor stimull, providing insight to OMP function. The maximal electroolfactogram response of the olfactory neuroepithelium to several odorants was 20-40% smaller in the mutants compared with controls. In addition, the onset and recovery kinetics following isoamyl acetate stimulation are prolonged in the null mice. Furthermore, the ability of the mutants to respond to the second odor pulse of a pair is impaired, over a range of concentrations, compared with controls. These results imply that neural activity directed toward the olfactory bulb is also reduced. The bulbar phenotype observed in the OMP-null mouse is consistent with this hypothesis. Bulbar activity of tyrosine hydroxylase, the rate limiting enzyme of catecholamine biosynthesis, and content of the neuropeptide cholecystokinin are reduced by 65% and 50%, respectively. This similarity to postsynaptic changes in gene expression induced by peripheral olfactory deafferentation or naris blockade confirms that functional neural activity is reduced in both the olfactory neuroepithelium and the olfactory nerve projection to the bulb in the OMP-null mouse. These observations provide strong support for the conclusion that OMP is a novel modulatory component of the odor detection/signal transduction cascade. Images Fig. 1 Fig. 2 PMID:8790421

  8. Olfactory marker protein (OMP) gene deletion causes altered physiological activity of olfactory sensory neurons.

    PubMed

    Buiakova, O I; Baker, H; Scott, J W; Farbman, A; Kream, R; Grillo, M; Franzen, L; Richman, M; Davis, L M; Abbondanzo, S; Stewart, C L; Margolis, F L

    1996-09-01

    Olfactory marker protein (OMP) is an abundant, phylogentically conserved, cytoplasmic protein of unknown function expressed almost exclusively in mature olfactory sensory neurons. To address its function, we generated OMP-deficient mice by gene targeting in embryonic stem cells. We report that these OMP-null mice are compromised in their ability to respond to odor stimull, providing insight to OMP function. The maximal electroolfactogram response of the olfactory neuroepithelium to several odorants was 20-40% smaller in the mutants compared with controls. In addition, the onset and recovery kinetics following isoamyl acetate stimulation are prolonged in the null mice. Furthermore, the ability of the mutants to respond to the second odor pulse of a pair is impaired, over a range of concentrations, compared with controls. These results imply that neural activity directed toward the olfactory bulb is also reduced. The bulbar phenotype observed in the OMP-null mouse is consistent with this hypothesis. Bulbar activity of tyrosine hydroxylase, the rate limiting enzyme of catecholamine biosynthesis, and content of the neuropeptide cholecystokinin are reduced by 65% and 50%, respectively. This similarity to postsynaptic changes in gene expression induced by peripheral olfactory deafferentation or naris blockade confirms that functional neural activity is reduced in both the olfactory neuroepithelium and the olfactory nerve projection to the bulb in the OMP-null mouse. These observations provide strong support for the conclusion that OMP is a novel modulatory component of the odor detection/signal transduction cascade. PMID:8790421

  9. Relating 7-Month-Olds Visuo-Spatial Working Memory to Other Basic Mental Skills Assessed with Two Different Versions of the Habituation-Dishabituation Paradigm

    ERIC Educational Resources Information Center

    Ropeter, Anna; Pauen, Sabina

    2013-01-01

    This study examines the relationship between various basic mental processing abilities in infancy. Two groups of 7-month-olds received the same delayed-response task to assess visuo-spatial working memory, but two different habituation-dishabituation tasks to assess processing speed and recognition memory. The single-stimulus group ("N"…

  10. Effects of Olfactory Stimulation from the Fragrance of the Japanese Citrus Fruit Yuzu (Citrus junos Sieb. ex Tanaka) on Mood States and Salivary Chromogranin A as an Endocrinologic Stress Marker

    PubMed Central

    Asakura, Hiroyuki; Hayashi, Tatsuya

    2014-01-01

    Abstract Objective: This study investigated the soothing effects of fragrance from yuzu, a Japanese citrus fruit (Citrus junos Sieb. ex Tanaka), with salivary chromogranin A (CgA) used as an endocrinologic stress marker reflecting sympathetic nervous system activity. Methods: Twenty healthy women (mean age, 20.5±0.1 years) participated in a randomized, controlled, crossover study. Participants were examined on two separate occasions—once using the yuzu scent and once using unscented water as a control—in the follicular phase. This experiment measured salivary CgA and the Profile of Mood States (POMS) as a psychological index before and after the aromatic stimulation. Results: Ten-minute inhalation of the yuzu scent significantly decreased salivary CgA. At 30 minutes after the inhalation period, the salivary CgA level further decreased. In addition, POMS revealed that inhalation of the aromatic yuzu oil significantly decreased total mood disturbance, a global measure of affective state, as well as four subscores of emotional symptoms (tension–anxiety, depression–dejection, anger–hostility, and confusion), as long as 30 minutes after the olfactory stimulation. Conclusions: Yuzu's aromatic effects may alleviate negative emotional stress, which, at least in part, would contribute to the suppression of sympathetic nervous system activity. PMID:24742226

  11. 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.

  12. Sleep and olfactory cortical plasticity

    PubMed Central

    Barnes, Dylan C.; Wilson, Donald A.

    2014-01-01

    In many systems, sleep plays a vital role in memory consolidation and synaptic homeostasis. These processes together help store information of biological significance and reset synaptic circuits to facilitate acquisition of information in the future. In this review, we describe recent evidence of sleep-dependent changes in olfactory system structure and function which contribute to odor memory and perception. During slow-wave sleep, the piriform cortex becomes hypo-responsive to odor stimulation and instead displays sharp-wave activity similar to that observed within the hippocampal formation. Furthermore, the functional connectivity between the piriform cortex and other cortical and limbic regions is enhanced during slow-wave sleep compared to waking. This combination of conditions may allow odor memory consolidation to occur during a state of reduced external interference and facilitate association of odor memories with stored hedonic and contextual cues. Evidence consistent with sleep-dependent odor replay within olfactory cortical circuits is presented. These data suggest that both the strength and precision of odor memories is sleep-dependent. The work further emphasizes the critical role of synaptic plasticity and memory in not only odor memory but also basic odor perception. The work also suggests a possible link between sleep disturbances that are frequently co-morbid with a wide range of pathologies including Alzheimer’s disease, schizophrenia and depression and the known olfactory impairments associated with those disorders. PMID:24795585

  13. Odorant Metabolism Catalyzed by Olfactory Mucosal Enzymes Influences Peripheral Olfactory Responses in Rats

    PubMed Central

    Thiebaud, Nicolas; Veloso Da Silva, Stéphanie; Jakob, Ingrid; Sicard, Gilles; Chevalier, Joëlle; Ménétrier, Franck; Berdeaux, Olivier; Artur, Yves; Heydel, Jean-Marie; Le Bon, Anne-Marie

    2013-01-01

    A large set of xenobiotic-metabolizing enzymes (XMEs), such as the cytochrome P450 monooxygenases (CYPs), esterases and transferases, are highly expressed in mammalian olfactory mucosa (OM). These enzymes are known to catalyze the biotransformation of exogenous compounds to facilitate elimination. However, the functions of these enzymes in the olfactory epithelium are not clearly understood. In addition to protecting against inhaled toxic compounds, these enzymes could also metabolize odorant molecules, and thus modify their stimulating properties or inactivate them. In the present study, we investigated the in vitro biotransformation of odorant molecules in the rat OM and assessed the impact of this metabolism on peripheral olfactory responses. Rat OM was found to efficiently metabolize quinoline, coumarin and isoamyl acetate. Quinoline and coumarin are metabolized by CYPs whereas isoamyl acetate is hydrolyzed by carboxylesterases. Electro-olfactogram (EOG) recordings revealed that the hydroxylated metabolites derived from these odorants elicited lower olfactory response amplitudes than the parent molecules. We also observed that glucurono-conjugated derivatives induced no olfactory signal. Furthermore, we demonstrated that the local application of a CYP inhibitor on rat olfactory epithelium increased EOG responses elicited by quinoline and coumarin. Similarly, the application of a carboxylesterase inhibitor increased the EOG response elicited by isoamyl acetate. This increase in EOG amplitude provoked by XME inhibitors is likely due to enhanced olfactory sensory neuron activation in response to odorant accumulation. Taken together, these findings strongly suggest that biotransformation of odorant molecules by enzymes localized to the olfactory mucosa may change the odorant’s stimulating properties and may facilitate the clearance of odorants to avoid receptor saturation. PMID:23555703

  14. 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.

  15. Nitric Oxide-Mediated Modulation of Central Network Dynamics during Olfactory Perception.

    PubMed

    Watanabe, Satoshi; Takanashi, Fumihito; Ishida, Kohei; Kobayashi, Suguru; Kitamura, Yoshiichiro; Hamasaki, Yuuta; Saito, Minoru

    2015-01-01

    Nitric oxide (NO) modulates the dynamics of central olfactory networks and has been implicated in olfactory processing including learning. Land mollusks have a specialized olfactory lobe in the brain called the procerebral (PC) lobe. The PC lobe produces ongoing local field potential (LFP) oscillation, which is modulated by olfactory stimulation. We hypothesized that NO should be released in the PC lobe in response to olfactory stimulation, and to prove this, we applied an NO electrode to the PC lobe of the land slug Limax in an isolated tentacle-brain preparation. Olfactory stimulation applied to the olfactory epithelium transiently increased the NO concentration in the PC lobe, and this was blocked by the NO synthase inhibitor L-NAME at 3.7 mM. L-NAME at this concentration did not block the ongoing LFP oscillation, but did block the frequency increase during olfactory stimulation. Olfactory stimulation also enhanced spatial synchronicity of activity, and this response was also blocked by L-NAME. Single electrical stimulation of the superior tentacle nerve (STN) mimicked the effects of olfactory stimulation on LFP frequency and synchronicity, and both of these effects were blocked by L-NAME. L-NAME did not block synaptic transmission from the STN to the nonbursting (NB)-type PC lobe neurons, which presumably produce NO in an activity-dependent manner. Previous behavioral experiments have revealed impairment of olfactory discrimination after L-NAME injection. The recording conditions in the present work likely reproduce the in vivo brain state in those behavioral experiments. We speculate that the dynamical effects of NO released during olfactory perception underlie precise odor representation and memory formation in the brain, presumably through regulation of NB neuron activity. PMID:26360020

  16. Nitric Oxide-Mediated Modulation of Central Network Dynamics during Olfactory Perception

    PubMed Central

    Kobayashi, Suguru; Kitamura, Yoshiichiro; Hamasaki, Yuuta; Saito, Minoru

    2015-01-01

    Nitric oxide (NO) modulates the dynamics of central olfactory networks and has been implicated in olfactory processing including learning. Land mollusks have a specialized olfactory lobe in the brain called the procerebral (PC) lobe. The PC lobe produces ongoing local field potential (LFP) oscillation, which is modulated by olfactory stimulation. We hypothesized that NO should be released in the PC lobe in response to olfactory stimulation, and to prove this, we applied an NO electrode to the PC lobe of the land slug Limax in an isolated tentacle-brain preparation. Olfactory stimulation applied to the olfactory epithelium transiently increased the NO concentration in the PC lobe, and this was blocked by the NO synthase inhibitor L-NAME at 3.7 mM. L-NAME at this concentration did not block the ongoing LFP oscillation, but did block the frequency increase during olfactory stimulation. Olfactory stimulation also enhanced spatial synchronicity of activity, and this response was also blocked by L-NAME. Single electrical stimulation of the superior tentacle nerve (STN) mimicked the effects of olfactory stimulation on LFP frequency and synchronicity, and both of these effects were blocked by L-NAME. L-NAME did not block synaptic transmission from the STN to the nonbursting (NB)-type PC lobe neurons, which presumably produce NO in an activity-dependent manner. Previous behavioral experiments have revealed impairment of olfactory discrimination after L-NAME injection. The recording conditions in the present work likely reproduce the in vivo brain state in those behavioral experiments. We speculate that the dynamical effects of NO released during olfactory perception underlie precise odor representation and memory formation in the brain, presumably through regulation of NB neuron activity. PMID:26360020

  17. Olfactory Mucosa Tissue Based Biosensor for Bioelectronic Nose

    NASA Astrophysics Data System (ADS)

    Liu, Qingjun; Ye, Weiwei; Yu, Hui; Hu, Ning; Cai, Hua; Wang, Ping

    2009-05-01

    Biological olfactory system can distinguish thousands of odors. In order to realize the biomimetic design of electronic nose on the principle of mammalian olfactory system, we have reported bioelectronic nose based on cultured olfactory cells. In this study, the electrical property of the tissue-semiconductor interface was analyzed by the volume conductor theory and the sheet conductor model. Olfactory mucosa tissue of rat was isolated and fixed on the surface of the light-addressable potentiometric sensor (LAPS), with the natural stations of the neuronal populations and functional receptor unit of the cilia well reserved. By the extracellular potentials of the olfactory receptor cells of the mucosa tissue monitored, both the simulation and the experimental results suggested that this tissue-semiconductor hybrid system was sensitive to odorants stimulation.

  18. Unique Neural Circuitry for Neonatal Olfactory Learning

    PubMed Central

    Moriceau, Stephanie; Sullivan, Regina M.

    2007-01-01

    Imprinting ensures that the infant forms the caregiver attachment necessary for altricial species survival. In our mammalian model of imprinting, neonatal rats rapidly learn the odor-based maternal attachment. This rapid learning requires reward-evoked locus ceruleus (LC) release of copious amounts of norepinephrine (NE) into the olfactory bulb. This imprinting ends at postnatal day 10 (P10) and is associated with a dramatic reduction in reward-evoked LC NE release. Here we assess whether the functional emergence of LC α2 inhibitory autoreceptors and the downregulation of LC α1 excitatory autoreceptors underlie the dramatic reduction in NE release associated with termination of the sensitive period. Postsensitive period pups (P12) were implanted with either LC or olfactory bulb cannulas, classically conditioned with intracranial drug infusions (P14), and tested for an odor preference (P15). During conditioning, a novel odor was paired with either olfactory bulb infusion of a β-receptor agonist (isoproterenol) to assess the target effects of NE or direct LC cholinergic stimulation combined with α2 antagonists and α1 agonists in a mixture to reinstate neonatal levels of LC autoreceptor activity to assess the source of NE. Pups learned an odor preference when the odor was paired with either olfactory bulb isoproterenol infusion or reinstatement of neonatal LC receptor activity. These results suggest that LC autoreceptor functional changes rather than olfactory bulb changes underlie sensitive period termination. PMID:14762136

  19. Olfactory Signal Transduction in the Mouse Septal Organ

    PubMed Central

    Ma, Minghong; Grosmaitre, Xavier; Iwema, Carrie L.; Baker, Harriet; Greer, Charles A.; Shepherd, Gordon M.

    2008-01-01

    The septal organ, a distinct chemosensory organ observed in the mammalian nose, is essentially a small island of olfactory neuroepithelium located bilaterally at the ventral base of the nasal septum. Virtually nothing is known about its physiological properties and function. To understand the nature of the sensory neurons in this area, we studied the mechanisms underlying olfactory signal transduction in these neurons. The majority of the sensory neurons in the septal organ express olfactory-specific G-protein and adenylyl cyclase type III, suggesting that the cAMP signaling pathway plays a critical role in the septal organ as in the main olfactory epithelium (MOE). This is further supported by patch-clamp recordings from individual dendritic knobs of the sensory neurons in the septal organ. Odorant responses can be mimicked by an adenylyl cyclase activator and a phosphodiesterase inhibitor, and these responses can be blocked by an adenylyl cyclase inhibitor. There is a small subset of cells in the septal organ expressing a cGMP-stimulated phosphodiesterase (phosphodiesterase 2), a marker for the guanylyl cyclase-D subtype sensory neurons identified in the MOE. The results indicate that the septal organ resembles the MOE in major olfactory signal transduction pathways, odorant response properties, and projection to the main olfactory bulb. Molecular and functional analysis of the septal organ, which constitutes ~1% of the olfactory epithelium, will provide new insights into the organization of the mammalian olfactory system and the unique function this enigmatic organ may serve. PMID:12514230

  20. Integrating temperature with odor processing in the olfactory bulb.

    PubMed

    Kludt, Eugen; Okom, Camille; Brinkmann, Alexander; Schild, Detlev

    2015-05-20

    Temperature perception has long been classified as a somesthetic function solely. However, in recent years several studies brought evidence that temperature perception also takes place in the olfactory system of rodents. Temperature has been described as an effective stimulus for sensory neurons of the Grueneberg ganglion located at the entrance of the nose. Here, we investigate whether a neuronal trace of temperature stimulation can be observed in the glomeruli and mitral cells of the olfactory bulb, using calcium imaging and fast line-scanning microscopy. We show in the Xenopus tadpole system that the γ-glomerulus, which receives input from olfactory neurons, is highly sensitive to temperature drops at the olfactory epithelium. We observed that thermo-induced activity in the γ-glomerulus is conveyed to the mitral cells innervating this specific neuropil. Surprisingly, a substantial number of thermosensitive mitral cells were also chemosensitive. Moreover, we report another unique feature of the γ-glomerulus: it receives ipsilateral and contralateral afferents. The latter fibers pass through the contralateral bulb, cross the anterior commissure, and then run to the ipsilateral olfactory bulb, where they target the γ-glomerulus. Temperature drops at the contralateral olfactory epithelium also induced responses in the γ-glomerulus and in mitral cells. Temperature thus appears to be a relevant physiological input to the Xenopus olfactory system. Each olfactory bulb integrates and codes temperature signals originating from receptor neurons of the ipsilateral and contralateral nasal cavities. Finally, temperature and chemical information is processed in shared cellular networks. PMID:25995474

  1. 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…

  2. 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. PMID:26441369

  3. The role of the olfactory recess in olfactory airflow.

    PubMed

    Eiting, Thomas P; Smith, Timothy D; Perot, J Blair; Dumont, Elizabeth R

    2014-05-15

    The olfactory recess - a blind pocket at the back of the nasal airway - is thought to play an important role in mammalian olfaction by sequestering air outside of the main airstream, thus giving odorants time to re-circulate. Several studies have shown that species with large olfactory recesses tend to have a well-developed sense of smell. However, no study has investigated how the size of the olfactory recess relates to air circulation near the olfactory epithelium. Here we used a computer model of the nasal cavity from a bat (Carollia perspicillata) to test the hypothesis that a larger olfactory recess improves olfactory airflow. We predicted that during inhalation, models with an enlarged olfactory recess would have slower rates of flow through the olfactory region (i.e. the olfactory recess plus airspace around the olfactory epithelium), while during exhalation these models would have little to no flow through the olfactory recess. To test these predictions, we experimentally modified the size of the olfactory recess while holding the rest of the morphology constant. During inhalation, we found that an enlarged olfactory recess resulted in lower rates of flow in the olfactory region. Upon exhalation, air flowed through the olfactory recess at a lower rate in the model with an enlarged olfactory recess. Taken together, these results indicate that an enlarged olfactory recess improves olfactory airflow during both inhalation and exhalation. These findings add to our growing understanding of how the morphology of the nasal cavity may relate to function in this understudied region of the skull. PMID:24577441

  4. Olfactory responsiveness to two odorous steroids in three species of nonhuman primates.

    PubMed

    Laska, Matthias; Wieser, Alexandra; Hernandez Salazar, Laura Teresa

    2005-07-01

    Social communication by means of odor signals is widespread among mammals. In pigs, for example, the C19-steroids 5-alpha-androst-16-en-3-one and 5-alpha-androst-16-en-3-ol are secreted by the boar and induce the mating stance in the sow. In humans, the same substances have been shown to be compounds of body odor and are presumed to affect human behavior. Using an instrumental conditioning paradigm, we here show that squirrel monkeys, spider monkeys and pigtail macaques are able to detect androstenone at concentrations in the micromolar range and thus at concentrations at least as low as those reported in pigs and humans. All three species of nonhuman primates were considerably less sensitive to androstenol, which was detected at concentrations in the millimolar range. Additional tests, using a habituation-dishabituation paradigm, showed that none of the 10 animals tested per species was anosmic to the two odorous steroids. These results suggest that androstenone and androstenol may be involved in olfactory communication in the primate species tested and that the specific anosmia to these odorants found in approximately 30% of human subjects may be due to their reduced number of functional olfactory receptor genes compared with nonhuman primates. PMID:15961521

  5. Adiponectin enhances the responsiveness of the olfactory system.

    PubMed

    Loch, Diana; Heidel, Christian; Breer, Heinz; Strotmann, Jörg

    2013-01-01

    The peptide hormone adiponectin is secreted by adipose tissue and the circulating concentration is reversely correlated with body fat mass; it is considered as starvation signal. The observation that mature sensory neurons of the main olfactory epithelium express the adiponectin receptor 1 has led to the concept that adiponectin may affect the responsiveness of the olfactory system. In fact, electroolfactogram recordings from olfactory epithelium incubated with exogenous adiponectin resulted in large amplitudes upon odor stimulation. To determine whether the responsiveness of the olfactory sensory neurons was enhanced, we have monitored the odorant-induced expression of the immediate early gene Egr1. It was found that in an olfactory epithelium incubated with nasally applied adiponectin the number of Egr1 positive cells was significantly higher compared to controls, suggesting that adiponectin rendered the olfactory neurons more responsive to an odorant stimulus. To analyze whether the augmented responsiveness of sensory neurons was strong enough to elicit a higher neuronal activity in the olfactory bulb, the number of activated periglomerular cells of a distinct glomerulus was determined by monitoring the stimulus-induced expression of c-fos. The studies were performed using the transgenic mOR256-17-IRES-tauGFP mice which allowed to visualize the corresponding glomerulus and to stimulate with a known ligand. The data indicate that upon exposure to 2,3-hexanedione in adiponectin-treated mice the number of activated periglomerular neurons was significantly increased compared to controls. The results of this study indicate that adiponectin increases the responsiveness of the olfactory system, probably due to a higher responsiveness of olfactory sensory neurons. PMID:24130737

  6. Adiponectin Enhances the Responsiveness of the Olfactory System

    PubMed Central

    Loch, Diana; Heidel, Christian; Breer, Heinz; Strotmann, Jörg

    2013-01-01

    The peptide hormone adiponectin is secreted by adipose tissue and the circulating concentration is reversely correlated with body fat mass; it is considered as starvation signal. The observation that mature sensory neurons of the main olfactory epithelium express the adiponectin receptor 1 has led to the concept that adiponectin may affect the responsiveness of the olfactory system. In fact, electroolfactogram recordings from olfactory epithelium incubated with exogenous adiponectin resulted in large amplitudes upon odor stimulation. To determine whether the responsiveness of the olfactory sensory neurons was enhanced, we have monitored the odorant-induced expression of the immediate early gene Egr1. It was found that in an olfactory epithelium incubated with nasally applied adiponectin the number of Egr1 positive cells was significantly higher compared to controls, suggesting that adiponectin rendered the olfactory neurons more responsive to an odorant stimulus. To analyze whether the augmented responsiveness of sensory neurons was strong enough to elicit a higher neuronal activity in the olfactory bulb, the number of activated periglomerular cells of a distinct glomerulus was determined by monitoring the stimulus-induced expression of c-fos. The studies were performed using the transgenic mOR256-17-IRES-tauGFP mice which allowed to visualize the corresponding glomerulus and to stimulate with a known ligand. The data indicate that upon exposure to 2,3-hexanedione in adiponectin-treated mice the number of activated periglomerular neurons was significantly increased compared to controls. The results of this study indicate that adiponectin increases the responsiveness of the olfactory system, probably due to a higher responsiveness of olfactory sensory neurons. PMID:24130737

  7. Ionotropic Crustacean Olfactory Receptors

    PubMed Central

    Corey, Elizabeth A.; Bobkov, Yuriy; Ukhanov, Kirill; Ache, Barry W.

    2013-01-01

    The nature of the olfactory receptor in crustaceans, a major group of arthropods, has remained elusive. We report that spiny lobsters, Panulirus argus, express ionotropic receptors (IRs), the insect chemosensory variants of ionotropic glutamate receptors. Unlike insects IRs, which are expressed in a specific subset of olfactory cells, two lobster IR subunits are expressed in most, if not all, lobster olfactory receptor neurons (ORNs), as confirmed by antibody labeling and in situ hybridization. Ligand-specific ORN responses visualized by calcium imaging are consistent with a restricted expression pattern found for other potential subunits, suggesting that cell-specific expression of uncommon IR subunits determines the ligand sensitivity of individual cells. IRs are the only type of olfactory receptor that we have detected in spiny lobster olfactory tissue, suggesting that they likely mediate olfactory signaling. Given long-standing evidence for G protein-mediated signaling in activation of lobster ORNs, this finding raises the interesting specter that IRs act in concert with second messenger-mediated signaling. PMID:23573266

  8. Ionotropic crustacean olfactory receptors.

    PubMed

    Corey, Elizabeth A; Bobkov, Yuriy; Ukhanov, Kirill; Ache, Barry W

    2013-01-01

    The nature of the olfactory receptor in crustaceans, a major group of arthropods, has remained elusive. We report that spiny lobsters, Panulirus argus, express ionotropic receptors (IRs), the insect chemosensory variants of ionotropic glutamate receptors. Unlike insects IRs, which are expressed in a specific subset of olfactory cells, two lobster IR subunits are expressed in most, if not all, lobster olfactory receptor neurons (ORNs), as confirmed by antibody labeling and in situ hybridization. Ligand-specific ORN responses visualized by calcium imaging are consistent with a restricted expression pattern found for other potential subunits, suggesting that cell-specific expression of uncommon IR subunits determines the ligand sensitivity of individual cells. IRs are the only type of olfactory receptor that we have detected in spiny lobster olfactory tissue, suggesting that they likely mediate olfactory signaling. Given long-standing evidence for G protein-mediated signaling in activation of lobster ORNs, this finding raises the interesting specter that IRs act in concert with second messenger-mediated signaling. PMID:23573266

  9. Trials and intensity effects in single-trial ERP components and autonomic responses in a dishabituation paradigm with very long ISIs.

    PubMed

    MacDonald, Brett; Barry, Robert J; Bonfield, Rebecca C

    2015-12-01

    The phasic orienting reflex (OR) was investigated using single-trial data collected concurrently from 4 autonomic measures and event-related potentials (ERPs). In an auditory dishabituation paradigm, twelve indifferent tones of two intensities (60 or 80 dB, intensity change on trial 11, counterbalanced between subjects) were presented at very long interstimulus intervals (ISIs). Novelty and intensity based stimulus-response patterns were examined seeking ERP analogues of autonomic measures representing pre-OR and OR processing. Skin conductance response (SCR) represented the phasic OR index. EOG-corrected ERP data for 16 subjects were decomposed by a temporal Principal Components Analysis (PCA). SCR diminished over 10 standard trials, recovered on change trial 11, dishabituated to the re-presentation of the standard tone on trial 12, and showed intensity effects at the change - formal requirements for an OR index. The evoked cardiac response (HR) showed no trial or intensity effects. Respiratory pause (RP) decreased linearly over trials and showed recovery but no dishabituation or intensity effect. Peripheral vasoconstriction (PVC) failed to decrement but exhibited an intensity effect. Ten identifiable ERP components were extracted: Na, P1, N1-1, PN, P2, P3a, P3b, a novelty-sensitive HabP3, an intensity-sensitive IntP3, and the Slow Wave (SW). Pattern 1 showed no trial or intensity effects (HR, P1, PN, P2); Pattern 2 showed no trial effect but an intensity effect (PVC, Na, N1-1, P3a); and Pattern 3 demonstrated habituation and an intensity effect (SCR, RP, P3b, HabP3, IntP3, SW). The observed fractionation of autonomic and central measures is consistent with Preliminary Process Theory (PPT) rather than the notion of a unitary OR. PMID:26255255

  10. Olfactory processing: detection of rapid changes.

    PubMed

    Croy, Ilona; Krone, Franziska; Walker, Susannah; Hummel, Thomas

    2015-06-01

    Changes in the olfactory environment have a rather poor chance of being detected. Aim of the present study was to determine, whether the same (cued) or different (uncued) odors can generally be detected at short inter stimulus intervals (ISI) below 2.5 s. Furthermore we investigated, whether inhibition of return, an attentional phenomenon facilitating the detection of new stimuli at longer ISI, is present in the domain of olfaction. Thirteen normosmic people (3 men, 10 women; age range 19-27 years; mean age 23 years) participated. Stimulation was performed using air-dilution olfactometry with 2 odors: phenylethylalcohol and hydrogen disulfide. Reaction time to target stimuli was assessed in cued and uncued conditions at ISIs of 1, 1.5, 2, and 2.5 s. There was a significant main effect of ISI, indicating that odors presented only 1 s apart are missed frequently. Uncued presentation facilitated detection at short ISIs, implying that changes of the olfactory environment are detected better than presentation of the same odor again. Effects in relation to "olfactory inhibition of return," on the other hand, are not supported by our results. This suggests that attention works different for the olfactory system compared with the visual and auditory systems. PMID:25911421

  11. 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

  12. The muted sense: neurocognitive limitations of olfactory language

    PubMed Central

    Olofsson, Jonas K.; Gottfried, Jay A.

    2015-01-01

    Most people find it profoundly difficult to name familiar smells. This difficulty persists even though perceptual odor processing and visual object naming are unimpaired, implying deficient sensory-specific interactions with the language system. In this article, we synthesize recent behavioral and neuroimaging data to develop a biologically informed framework for olfactory lexical processing in the human brain. Our central premise is that the difficulty in naming common objects through olfactory (compared to visual) stimulation is the end result of cumulative effects occurring at three successive stages of the olfactory language pathway: object perception, lexical-semantic integration, and verbalization. Understanding the neurocognitive mechanisms by which the language network interacts with olfaction can yield unique insights into the elusive nature of olfactory naming. PMID:25979848

  13. The muted sense: neurocognitive limitations of olfactory language.

    PubMed

    Olofsson, Jonas K; Gottfried, Jay A

    2015-06-01

    Most people find it profoundly difficult to name familiar smells. This difficulty persists even when perceptual odor processing and visual object naming are unimpaired, implying deficient sensory-specific interactions with the language system. Here we synthesize recent behavioral and neuroimaging data to develop a biologically informed framework for olfactory lexical processing in the human brain. Our central premise is that the difficulty in naming common objects through olfactory (compared with visual) stimulation is the end result of cumulative effects occurring at three successive stages of the olfactory language pathway: object perception, lexical-semantic integration, and verbalization. Understanding the neurocognitive mechanisms by which the language network interacts with olfaction can yield unique insights into the elusive nature of olfactory naming. PMID:25979848

  14. Olfactory receptor neuron responses coding for rapid odour sampling

    PubMed Central

    Ghatpande, Ambarish S; Reisert, Johannes

    2011-01-01

    Abstract Vertebrate olfactory receptor neurons (ORNs) are stimulated in a rhythmic manner in vivo, driven by delivery of odorants to the nasal cavity carried by the inhaled air, making olfaction a sense where animals can control the frequency of stimulus delivery. How ORNs encode repeated stimulation at resting, low breathing frequencies and at increased sniffing frequencies is not known, nor is it known if the olfactory transduction cascade is accurate and fast enough to follow high frequency stimulation. We investigated mouse olfactory responses to stimulus frequencies mimicking odorant exposure during low (2 Hz) and high (5 Hz) frequency sniffing. ORNs reliably follow low frequency stimulations with high fidelity by generating bursts of action potentials at each stimulation at intermediate odorant concentrations, but fail to do so at high odorant concentrations. Higher stimulus frequencies across all odorant concentrations reduced the likelihood of action potential generation, increased the latency of response, and decreased the reliability of encoding the onset of stimulation. Thus an increase in stimulus frequency degrades and at high odorant concentrations entirely prevents action potential generation in individual ORNs, causing reduced signalling to the olfactory bulb. These results demonstrate that ORNs do not simply relay timing and concentration of an odorous stimulus, but also process and modulate the stimulus in a frequency-dependent manner which is controlled by the chosen sniffing rate. PMID:21486768

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

    PubMed Central

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

    2012-01-01

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

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

    PubMed

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

    2012-10-10

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

  17. 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…

  18. Cellular Basis for the Olfactory Response to Nicotine

    PubMed Central

    2010-01-01

    Smokers regulate their smoking behavior on the basis of sensory stimuli independently of the pharmacological effects of nicotine (RoseJ. E., et al. (1993) Pharmacol., Biochem. Behav.1 (3), 891−9008469698). 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 (MombaertsP. (1999) Annu. Rev. Neurosci.1, 487−50910202546), we studied biopsied human olfactory sensory neurons (OSNs), cultured human olfactory cells (GomezG., et al. (2000) J. Neurosci. Res.1 (3), 737−74911104513), 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. PMID:22777075

  19. 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. PMID:22777075

  20. Adult Olfactory Bulb Neurogenesis.

    PubMed

    Lledo, Pierre-Marie; Valley, Matt

    2016-01-01

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

  1. Specificity and distribution of receptor cells in the olfactory mucosa of char (Salmo alpinus L.).

    PubMed

    Thommesen, G

    1982-05-01

    Olfactory receptor activity was studied in the char by two methods: (a) recording of the electro-olfactogram (EOG) with two electrodes simultaneously in the olfactory pit and (b) recordings from the olfactory bulb during olfactory stimulation and progressive removal of lamellae in the olfactory rosette. As stimuli were used methionine representing the amino acids and dilute char bile representing the bile salts. By cross-adaptation studies it was demonstrated that receptors sensitive to each of these two stimuli re functionally independent. The results show further that both types of receptors may be found on all lamellae, but differentially distributed within each lamella. Receptors sensitive to methionine are located closer to the raphe than receptors sensitive to bile. The spatial differentiation persists regardless of stimulus concentration. The results are discussed in relation to the projection and growth of primary nerve fibres into the olfactory bulb, and the existence of receptor cells with microvilli and with cilia. PMID:7136804

  2. Olfactory dysfunction in Alzheimer's disease.

    PubMed

    Zou, Yong-Ming; Lu, Da; Liu, Li-Ping; Zhang, Hui-Hong; Zhou, Yu-Ying

    2016-01-01

    Alzheimer's disease (AD) is a common neurodegenerative disorder with the earliest clinical symptom of olfactory dysfunction, which is a potential clinical marker for AD severity and progression. However, many questions remain unanswered. This article reviews relevant research on olfactory dysfunction in AD and evaluates the predictive value of olfactory dysfunction for the epidemiological, pathophysiological, and clinical features of AD, as well as for the conversion of cognitive impairment to AD. We summarize problems of existing studies and provide a useful reference for further studies in AD olfactory dysfunction and for clinical applications of olfactory testing. PMID:27143888

  3. Olfactory sensitivity in mammalian species.

    PubMed

    Wackermannová, M; Pinc, L; Jebavý, L

    2016-07-18

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

  4. Mechanisms of regulation of olfactory transduction and adaptation in the olfactory cilium.

    PubMed

    Antunes, Gabriela; Sebastião, Ana Maria; Simoes de Souza, Fabio Marques

    2014-01-01

    Olfactory adaptation is a fundamental process for the functioning of the olfactory system, but the underlying mechanisms regulating its occurrence in intact olfactory sensory neurons (OSNs) are not fully understood. In this work, we have combined stochastic computational modeling and a systematic pharmacological study of different signaling pathways to investigate their impact during short-term adaptation (STA). We used odorant stimulation and electroolfactogram (EOG) recordings of the olfactory epithelium treated with pharmacological blockers to study the molecular mechanisms regulating the occurrence of adaptation in OSNs. EOG responses to paired-pulses of odorants showed that inhibition of phosphodiesterases (PDEs) and phosphatases enhanced the levels of STA in the olfactory epithelium, and this effect was mimicked by blocking vesicle exocytosis and reduced by blocking cyclic adenosine monophosphate (cAMP)-dependent protein kinase (PKA) and vesicle endocytosis. These results suggest that G-coupled receptors (GPCRs) cycling is involved with the occurrence of STA. To gain insights on the dynamical aspects of this process, we developed a stochastic computational model. The model consists of the olfactory transduction currents mediated by the cyclic nucleotide gated (CNG) channels and calcium ion (Ca(2+))-activated chloride (CAC) channels, and the dynamics of their respective ligands, cAMP and Ca(2+), and it simulates the EOG results obtained under different experimental conditions through changes in the amplitude and duration of cAMP and Ca(2+) response, two second messengers implicated with STA occurrence. The model reproduced the experimental data for each pharmacological treatment and provided a mechanistic explanation for the action of GPCR cycling in the levels of second messengers modulating the levels of STA. All together, these experimental and theoretical results indicate the existence of a mechanism of regulation of STA by signaling pathways that control

  5. Mechanisms of Regulation of Olfactory Transduction and Adaptation in the Olfactory Cilium

    PubMed Central

    Antunes, Gabriela; Sebastião, Ana Maria; Simoes de Souza, Fabio Marques

    2014-01-01

    Olfactory adaptation is a fundamental process for the functioning of the olfactory system, but the underlying mechanisms regulating its occurrence in intact olfactory sensory neurons (OSNs) are not fully understood. In this work, we have combined stochastic computational modeling and a systematic pharmacological study of different signaling pathways to investigate their impact during short-term adaptation (STA). We used odorant stimulation and electroolfactogram (EOG) recordings of the olfactory epithelium treated with pharmacological blockers to study the molecular mechanisms regulating the occurrence of adaptation in OSNs. EOG responses to paired-pulses of odorants showed that inhibition of phosphodiesterases (PDEs) and phosphatases enhanced the levels of STA in the olfactory epithelium, and this effect was mimicked by blocking vesicle exocytosis and reduced by blocking cyclic adenosine monophosphate (cAMP)-dependent protein kinase (PKA) and vesicle endocytosis. These results suggest that G-coupled receptors (GPCRs) cycling is involved with the occurrence of STA. To gain insights on the dynamical aspects of this process, we developed a stochastic computational model. The model consists of the olfactory transduction currents mediated by the cyclic nucleotide gated (CNG) channels and calcium ion (Ca2+)-activated chloride (CAC) channels, and the dynamics of their respective ligands, cAMP and Ca2+, and it simulates the EOG results obtained under different experimental conditions through changes in the amplitude and duration of cAMP and Ca2+ response, two second messengers implicated with STA occurrence. The model reproduced the experimental data for each pharmacological treatment and provided a mechanistic explanation for the action of GPCR cycling in the levels of second messengers modulating the levels of STA. All together, these experimental and theoretical results indicate the existence of a mechanism of regulation of STA by signaling pathways that control GPCR

  6. Origin of basal activity in mammalian olfactory receptor neurons

    PubMed Central

    2010-01-01

    Mammalian odorant receptors form a large, diverse group of G protein–coupled receptors that determine the sensitivity and response profile of olfactory receptor neurons. But little is known if odorant receptors control basal and also stimulus-induced cellular properties of olfactory receptor neurons other than ligand specificity. This study demonstrates that different odorant receptors have varying degrees of basal activity, which drives concomitant receptor current fluctuations and basal action potential firing. This basal activity can be suppressed by odorants functioning as inverse agonists. Furthermore, odorant-stimulated olfactory receptor neurons expressing different odorant receptors can have strikingly different response patterns in the later phases of prolonged stimulation. Thus, the influence of odorant receptor choice on response characteristics is much more complex than previously thought, which has important consequences on odor coding and odor information transfer to the brain. PMID:20974772

  7. Electroolfactogram (EOG) Recording in the Mouse Main Olfactory Epithelium

    PubMed Central

    Chen, Xuanmao; Xia, Zhengui; Storm, Daniel R.

    2016-01-01

    Olfactory sensory neurons in the main olfactory epithelium (MOE) are responsible for detecting odorants and EOG recording is a reliable approach to analyze the peripheral olfactory function. However, recently we revealed that rodent MOE can also detect the air pressure caused by airflow. The sensation of airflow pressure and odorants may function in synergy to facilitate odorant perception during sniffing. We have reported that the pressure-sensitive response in the MOE can also be assayed by EOG recording. Here we describe procedures for pressure-sensitive as well as odorant-stimulated EOG measurement in the mouse MOE. The major difference between the pressure-sensitive EOG response and the odorant-stimulated response was whether to use pure air puff or use an odorized air puff.

  8. The Mouse Olfactory Peduncle

    PubMed Central

    Brunjes, Peter C; Kay, Rachel B; Arrivillaga, J. P

    2012-01-01

    The olfactory peduncle, the region connecting the olfactory bulb with the basal forebrain, contains several neural areas that have received relatively little attention. The present work includes studies that provide an overview of the region in the mouse. An analysis of cell soma size in pars principalis (pP) of the anterior olfactory nucleus (AON) revealed considerable differences in tissue organization between mice and rats. An unbiased stereological study of neuron number in the cell-dense regions of pars externa (pE) and pP of the AON of 3, 12 and 24 month-old mice indicated that pE has about 16,500 cells in 0.043 mm3and pP about 58,300 cells in 0.307 mm3. Quantitative Golgi studies of pyramidal neurons in pP suggested that mouse neurons are similar though smaller to those of the rat. An immunohistochemical analysis demonstrated that all peduncular regions (pE, pP, the dorsal peduncular cortex, ventral tenia tecta, and anterior olfactory tubercle and piriform cortex) have cells that express either calbindin, calretinin, parvalbumin, somatostatin, vasoactive intestinal polypeptide, neuropeptide Y or cholecystokinin (antigens commonly co-expressed by subspecies of GABAergic neurons), though the relative numbers of each cell type differs between zones. Finally, an electron microscopic comparison of the organization of myelinated fibers in lateral olfactory tract in the anterior and posterior peduncle indicated that the region is less orderly in mice than in the rat. The results provide a caveat for investigators who generalize data between species as both similarities and differences between the laboratory mouse and rat were observed. PMID:21618219

  9. Olfactory modulation of affective touch processing - A neurophysiological investigation.

    PubMed

    Croy, Ilona; Drechsler, Edda; Hamilton, Paul; Hummel, Thomas; Olausson, Håkan

    2016-07-15

    Touch can be highly emotional, and depending on the environment, it can be perceived as pleasant and comforting or disgusting and dangerous. Here, we studied the impact of context on the processing of tactile stimuli using a functional magnetic resonance imaging (fMRI) paradigm. This was achieved by embedding tactile stimulation in a variable olfactory environment. Twenty people were scanned with BOLD fMRI while receiving the following stimulus blocks: Slow stroking Touch, Civette odor (feces like), Rose odor, Touch+Civette, and Touch+Rose. Ratings of pleasantness and intensity of tactile stimuli and ratings of disgust and intensity of olfactory stimuli were collected. The impact of the olfactory context on the processing of touch was studied using covariance analyses. Coupling between olfactory processing and somatosensory processing areas was assessed with psychophysiological interaction analysis (PPI). A subjectively disgusting olfactory environment significantly reduced the perceived pleasantness of touch. The touch fMRI activation in the secondary somatosensory cortex, operculum 1 (OP1), was positively correlated with the disgust towards the odors. Decreased pleasantness of touch was related to decreased posterior insula activity. PPI analysis revealed a significant interaction between the OP1, posterior insula, and regions processing the disgust of odors (orbitofrontal cortex and amygdala). We conclude that the disgust evaluation of the olfactory environment moderates neural reactivity in somatosensory regions by upregulation of the OP1 and downregulation of the posterior insula. This adaptive regulation of affective touch processing may facilitate adaptive reaction to a potentially harmful stimulus. PMID:27138206

  10. Odor Enrichment Sculpts the Abundance of Olfactory Bulb Mitral Cells

    PubMed Central

    Johnson, Melissa Cavallin; Biju, K.C.; Hoffman, Joshua; Fadool, Debra Ann

    2013-01-01

    Mitral cells are the primary output cell from the olfactory bulb conveying olfactory sensory information to higher cortical areas. Gene-targeted deletion of the Shaker potassium channel Kv1.3 alters voltage-dependence and inactivation kinetics of mitral cell current properties, which contribute to the “Super-smeller” phenotype observed in Kv1.3-null mice. The goal of the current study was to determine if morphology and density are influenced by mitral cell excitability, olfactory environment, and stage of development. Wildtype (WT) and Kv1.3-null (KO) mice were exposed to a single odorant (peppermint or citralva) for 30 days. Under unstimulated conditions, postnatal day 20 KO mice had more mitral cells than their WT counterparts, but no difference in cell size. Odor-enrichment with peppermint, an olfactory and trigeminal stimulus, decreased the number of mitral cells in three month and one year old mice of both genotypes. Mitral cell density was most sensitive to odor-stimulation in three month WT mice. Enrichment at the same age with citralva, a purely olfactory stimulus, decreased cell density regardless of genotype. There were no significant changes in cell body shape in response to citralva exposure, but the cell area was greater in WT mice and selectively greater in the ventral region of the OB in KO mice. This suggests that trigeminal or olfactory stimulation may modify mitral cell area and density while not impacting cell body shape. Mitral cell density can therefore be modulated by the voltage and sensory environment to alter information processing or olfactory perception. PMID:23485739

  11. Acetylcholine and Olfactory Perceptual Learning

    PubMed Central

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

    2007-01-01

    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 cortex. These changes include enhanced representation of the molecular features of familiar odors by mitral cells in the olfactory bulb, and synthetic coding of multiple coincident odorant features into odor objects by cortical neurons. In this paper, data are reviewed that show the critical role of acetylcholine (Ach) in olfactory system function and plasticity, and cholinergic modulation of olfactory perceptual learning at both the behavioral and cortical level. PMID:14747514

  12. Sensitization of olfactory guanylyl cyclase to a specific imprinted odorant in coho salmon.

    PubMed

    Dittman, A H; Quinn, T P; Nevitt, G A; Hacker, B; Storm, D R

    1997-08-01

    The role of cGMP in olfactory signaling is not fully understood, but it is believed to play a modulatory role in intracellular signaling in vertebrate olfactory receptor neurons (ORNs). Here, we present evidence that cGMP in ORNs may play an important role in recognition of biologically relevant odors and olfactory learning. Specifically, we investigated the cellular mechanisms underlying olfactory imprinting in salmon. Salmon learn odors associated with their natal site as juveniles and later use these odors to guide their homing migration. This imprinting is believed to involve sensitization of the peripheral olfactory system to specific homestream odorants. We imprinted juvenile salmon to the odorant beta-phenylethyl alcohol (PEA) and examined the sensitivity of olfactory adenylyl and guanylyl cyclases to PEA during development. Stimulation of guanylyl cyclase activity by PEA was significantly greater in olfactory cilia isolated from PEA-imprinted salmon compared with PEA-naive fish only at the time of the homing migration, 2 years after PEA exposure. These results suggest that sensitization of olfactory guanylyl cyclase may play an important role in olfactory imprinting by salmon. PMID:9292727

  13. Smelly primes – when olfactory primes do or do not work

    PubMed Central

    Smeets, M. A. M.; Dijksterhuis, G. B.

    2014-01-01

    In applied olfactory cognition the effects that olfactory stimulation can have on (human) behavior are investigated. To enable an efficient application of olfactory stimuli a model of how they may lead to a change in behavior is proposed. To this end we use the concept of olfactory priming. Olfactory priming may prompt a special view on priming as the olfactory sense has some unique properties which make odors special types of primes. Examples of such properties are the ability of odors to influence our behavior outside of awareness, to lead to strong affective evaluations, to evoke specific memories, and to associate easily and quickly to other environmental stimuli. Opportunities and limitations for using odors as primes are related to these properties, and alternative explanations for reported findings are offered. Implications for olfactory semantic, construal, behavior and goal priming are given based on a brief overview of the priming literature from social psychology and from olfactory perception science. We end by formulating recommendations and ideas for a future research agenda and applications for olfactory priming. PMID:24575071

  14. Olfactory perceptual stability and discrimination.

    PubMed

    Barnes, Dylan C; Hofacer, Rylon D; Zaman, Ashiq R; Rennaker, Robert L; Wilson, Donald A

    2008-12-01

    No two roses smell exactly alike, but our brain accurately bundles these variations into a single percept 'rose'. We found that ensembles of rat olfactory bulb neurons decorrelate complex mixtures that vary by as little as a single missing component, whereas olfactory (piriform) cortical neural ensembles perform pattern completion in response to an absent component, essentially filling in the missing information and allowing perceptual stability. This piriform cortical ensemble activity predicts olfactory perception. PMID:18978781

  15. Attention and olfactory consciousness.

    PubMed

    Keller, Andreas

    2011-01-01

    Understanding the relation between attention and consciousness is an important part of our understanding of consciousness. Attention, unlike consciousness, can be systematically manipulated in psychophysical experiments and a law-like relation between attention and consciousness is waiting to be discovered. Most attempts to discover the nature of this relation are focused on a special type of attention: spatial visual attention. In this review I want to introduce another type of attention to the discussion: attention to the olfactory modality. I will first clarify the position of attention to smells in a general taxonomy of attention. I will then review the mechanisms and neuroanatomy of attention and consciousness in the olfactory system before using the newly introduced system to provide evidence that attention is necessary for consciousness. PMID:22203813

  16. 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.

  17. Olfactory receptor patterning in a higher primate.

    PubMed

    Horowitz, Lisa F; Saraiva, Luis R; Kuang, Donghui; Yoon, Kyoung-hye; Buck, Linda B

    2014-09-10

    The mammalian olfactory system detects a plethora of environmental chemicals that are perceived as odors or stimulate instinctive behaviors. Studies using odorant receptor (OR) genes have provided insight into the molecular and organizational strategies underlying olfaction in mice. One important unanswered question, however, is whether these strategies are conserved in primates. To explore this question, we examined the macaque, a higher primate phylogenetically close to humans. Here we report that the organization of sensory inputs in the macaque nose resembles that in mouse in some respects, but not others. As in mouse, neurons with different ORs are interspersed in the macaque nose, and there are spatial zones that differ in their complement of ORs and extend axons to different domains in the olfactory bulb of the brain. However, whereas the mouse has multiple discrete band-like zones, the macaque appears to have only two broad zones. It is unclear whether the organization of OR inputs in a rodent/primate common ancestor degenerated in primates or, alternatively became more sophisticated in rodents. The mouse nose has an additional small family of chemosensory receptors, called trace amine-associated receptors (TAARs), which may detect social cues. Here we find that TAARs are also expressed in the macaque nose, suggesting that TAARs may also play a role in human olfactory perception. We further find that one human TAAR responds to rotten fish, suggesting a possible role as a sentinel to discourage ingestion of food harboring pathogenic microorganisms. PMID:25209267

  18. Olfactory Receptor Patterning in a Higher Primate

    PubMed Central

    Horowitz, Lisa F.; Saraiva, Luis R.; Kuang, Donghui; Yoon, Kyoung-hye

    2014-01-01

    The mammalian olfactory system detects a plethora of environmental chemicals that are perceived as odors or stimulate instinctive behaviors. Studies using odorant receptor (OR) genes have provided insight into the molecular and organizational strategies underlying olfaction in mice. One important unanswered question, however, is whether these strategies are conserved in primates. To explore this question, we examined the macaque, a higher primate phylogenetically close to humans. Here we report that the organization of sensory inputs in the macaque nose resembles that in mouse in some respects, but not others. As in mouse, neurons with different ORs are interspersed in the macaque nose, and there are spatial zones that differ in their complement of ORs and extend axons to different domains in the olfactory bulb of the brain. However, whereas the mouse has multiple discrete band-like zones, the macaque appears to have only two broad zones. It is unclear whether the organization of OR inputs in a rodent/primate common ancestor degenerated in primates or, alternatively became more sophisticated in rodents. The mouse nose has an additional small family of chemosensory receptors, called trace amine-associated receptors (TAARs), which may detect social cues. Here we find that TAARs are also expressed in the macaque nose, suggesting that TAARs may also play a role in human olfactory perception. We further find that one human TAAR responds to rotten fish, suggesting a possible role as a sentinel to discourage ingestion of food harboring pathogenic microorganisms. PMID:25209267

  19. Gap junctions in olfactory neurons modulate olfactory sensitivity

    PubMed Central

    2010-01-01

    Background One of the fundamental questions in olfaction is whether olfactory receptor neurons (ORNs) behave as independent entities within the olfactory epithelium. On the basis that mature ORNs express multiple connexins, I postulated that gap junctional communication modulates olfactory responses in the periphery and that disruption of gap junctions in ORNs reduces olfactory sensitivity. The data collected from characterizing connexin 43 (Cx43) dominant negative transgenic mice OlfDNCX, and from calcium imaging of wild type mice (WT) support my hypothesis. Results I generated OlfDNCX mice that express a dominant negative Cx43 protein, Cx43/β-gal, in mature ORNs to inactivate gap junctions and hemichannels composed of Cx43 or other structurally related connexins. Characterization of OlfDNCX revealed that Cx43/β-gal was exclusively expressed in areas where mature ORNs resided. Real time quantitative PCR indicated that cellular machineries of OlfDNCX were normal in comparison to WT. Electroolfactogram recordings showed decreased olfactory responses to octaldehyde, heptaldehyde and acetyl acetate in OlfDNCX compared to WT. Octaldehyde-elicited glomerular activity in the olfactory bulb, measured according to odor-elicited c-fos mRNA upregulation in juxtaglomerular cells, was confined to smaller areas of the glomerular layer in OlfDNCX compared to WT. In WT mice, octaldehyde sensitive neurons exhibited reduced response magnitudes after application of gap junction uncoupling reagents and the effects were specific to subsets of neurons. Conclusions My study has demonstrated that altered assembly of Cx43 or structurally related connexins in ORNs modulates olfactory responses and changes olfactory activation maps in the olfactory bulb. Furthermore, pharmacologically uncoupling of gap junctions reduces olfactory activity in subsets of ORNs. These data suggest that gap junctional communication or hemichannel activity plays a critical role in maintaining olfactory

  20. Alteration of the stability of Bag-1 protein in the control of olfactory neuronal apoptosis.

    PubMed

    Sourisseau, T; Desbois, C; Debure, L; Bowtell, D D; Cato, A C; Schneikert, J; Moyse, E; Michel, D

    2001-04-01

    Normal apoptosis occurs continuously in the olfactory neuroepithelium of adult vertebrates, making it a useful model for studying neuronal apoptosis. Here we demonstrate that overexpression of the anti-apoptotic Bag-1 gene in olfactory neuronal cells confers a strong resistance to apoptosis. Conversely decreased levels of Bag-1 were found to precede a massive wave of olfactory neuronal apoptosis triggered by synaptic target ablation. We show that the decrease is brought about by ubiquitination and subsequent degradation of the Bag-1 protein. The ring finger protein Siah-2 is a likely candidate for the ubiquitination reaction since Siah-2 mRNA accumulated in lesioned olfactory neuroepithelium and overexpression of Siah-2 stimulated Bag-1 ubiquitination and degradation in transient expression assays. These results together identify destabilization of Bag-1 as a necessary step in olfactory neuronal apoptosis. PMID:11257006

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

    PubMed

    Dibattista, Michele; Reisert, Johannes

    2016-03-01

    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. PMID:26961953

  2. Olfactory sensitivity to bile acids in salmonid fishes.

    PubMed

    Døving, K B; Selset, R; Thommesen, G

    1980-02-01

    Monopolar DC-recordings were made simultaneously from two positions on the olfactory bulb of chars (Salmo alpinus L.) and graylings (Thymallus thymallu L.) using bile acids and amino acids as olfactory stimulants. The bile acids induced responses with characteristic spatial differences from those of the amino acids. The distribution of responses to bile acids indicated a neuronal activity in the medial part of the bulb. In contrast, amino acids elicit responses in the lateral part of the bulb. Taurine conjugated bile acids were up to 1 000 times more potent as olfactory stimuli than methionine. The results suggest that olfactory receptors are of two types, one responding to bile acids, the other to amino acids. 3 -alpha-hydroxysteroids are released from the fish into the water in quantities that suffice for detection by their olfactory system. The odorant potency of the bile acids, their evolutionary history and variability, together with their renowned adherent properties made them interesting candidates for specific signals in the acquatic environment. PMID:7376910

  3. Calcium and olfactory transduction.

    PubMed

    Winegar, B D; Rosick, E R; Schafer, R

    1988-01-01

    1. Inorganic cations, organic calcium antagonists, and calmodulin antagonists were applied to olfactory epithelia of frogs (Rana pipiens) while recording electroolfactogram (EOG) responses. 2. Inorganic cations inhibited EOGs in a rank order, reflecting their calcium channel blocking potency: La3+ greater than Zn2+ greater than Cd2+ greater than Al3+ greater than Ca2+ greater than Sr2+ greater than Co2+ greater than Ba2+ greater than Mg2+. Barium ion significantly enhanced EOGs immediately following application. 3. Diltiazem and verapamil produced dose-dependent EOG inhibition. 4. Calmodulin antagonists inhibited EOGs without correlation to their anti-calmodulin potency. PMID:2904344

  4. Electrophysiological evidence for the broad distribution of specific odorant receptor molecules across the olfactory organ of the channel catfish.

    PubMed

    Chang, Q; Caprio, J

    1996-10-01

    To determine if there is a spatial segregation of responsiveness to odorants within the olfactory epithelium, microelectrode recordings were obtained from small populations of olfactory receptor neurons located across different lamellar sensory regions of the olfactory organ of the channel catfish, lctalurus punctatus. Stimuli included L-alanine, L-methionine, L-arginine hydrochloride, L-glutamic acid, ATP and a mixture of bile salts-odorants previously reported to stimulate independent receptor sites in aquatic species. The peak integrated olfactory receptor responses at each recording site were standardized to the response to L-alanine. The relative stimulatory effectiveness of the stimuli was preserved across the 10 olfactory lamellae recording sites. These data support previous molecular biological results of a broad distribution of receptor neurons that express specific receptor genes across the olfactory organ of the channel catfish. PMID:8902281

  5. Calcium-activated chloride currents in olfactory sensory neurons from mice lacking bestrophin-2

    PubMed Central

    Pifferi, Simone; Dibattista, Michele; Sagheddu, Claudia; Boccaccio, Anna; Al Qteishat, Ahmed; Ghirardi, Filippo; Tirindelli, Roberto; Menini, Anna

    2009-01-01

    Olfactory sensory neurons use a chloride-based signal amplification mechanism to detect odorants. The binding of odorants to receptors in the cilia of olfactory sensory neurons activates a transduction cascade that involves the opening of cyclic nucleotide-gated channels and the entry of Ca2+ into the cilia. Ca2+ activates a Cl− current that produces an efflux of Cl− ions and amplifies the depolarization. The molecular identity of Ca2+-activated Cl− channels is still elusive, although some bestrophins have been shown to function as Ca2+-activated Cl− channels when expressed in heterologous systems. In the olfactory epithelium, bestrophin-2 (Best2) has been indicated as a candidate for being a molecular component of the olfactory Ca2+-activated Cl− channel. In this study, we have analysed mice lacking Best2. We compared the electrophysiological responses of the olfactory epithelium to odorant stimulation, as well as the properties of Ca2+-activated Cl− currents in wild-type (WT) and knockout (KO) mice for Best2. Our results confirm that Best2 is expressed in the cilia of olfactory sensory neurons, while odorant responses and Ca2+-activated Cl− currents were not significantly different between WT and KO mice. Thus, Best2 does not appear to be the main molecular component of the olfactory channel. Further studies are required to determine the function of Best2 in the cilia of olfactory sensory neurons. PMID:19622610

  6. A Novel Neural Substrate for the Transformation of Olfactory Inputs into Motor Output

    PubMed Central

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

    2010-01-01

    It is widely recognized that animals respond to odors by generating or modulating specific motor behaviors. These reactions are important for daily activities, reproduction, and survival. In the sea lamprey, mating occurs after ovulated females are attracted to spawning sites by male sex pheromones. The ubiquity and reliability of olfactory-motor behavioral responses in vertebrates suggest tight coupling between the olfactory system and brain areas controlling movements. However, the circuitry and the underlying cellular neural mechanisms remain largely unknown. Using lamprey brain preparations, and electrophysiology, calcium imaging, and tract tracing experiments, we describe the neural substrate responsible for transforming an olfactory input into a locomotor output. We found that olfactory stimulation with naturally occurring odors and pheromones induced large excitatory responses in reticulospinal cells, the command neurons for locomotion. We have also identified the anatomy and physiology of this circuit. The olfactory input was relayed in the medial part of the olfactory bulb, in the posterior tuberculum, in the mesencephalic locomotor region, to finally reach reticulospinal cells in the hindbrain. Activation of this olfactory-motor pathway generated rhythmic ventral root discharges and swimming movements. Our study bridges the gap between behavior and cellular neural mechanisms in vertebrates, identifying a specific subsystem within the CNS, dedicated to producing motor responses to olfactory inputs. PMID:21203583

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

    PubMed

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

    2010-01-01

    It is widely recognized that animals respond to odors by generating or modulating specific motor behaviors. These reactions are important for daily activities, reproduction, and survival. In the sea lamprey, mating occurs after ovulated females are attracted to spawning sites by male sex pheromones. The ubiquity and reliability of olfactory-motor behavioral responses in vertebrates suggest tight coupling between the olfactory system and brain areas controlling movements. However, the circuitry and the underlying cellular neural mechanisms remain largely unknown. Using lamprey brain preparations, and electrophysiology, calcium imaging, and tract tracing experiments, we describe the neural substrate responsible for transforming an olfactory input into a locomotor output. We found that olfactory stimulation with naturally occurring odors and pheromones induced large excitatory responses in reticulospinal cells, the command neurons for locomotion. We have also identified the anatomy and physiology of this circuit. The olfactory input was relayed in the medial part of the olfactory bulb, in the posterior tuberculum, in the mesencephalic locomotor region, to finally reach reticulospinal cells in the hindbrain. Activation of this olfactory-motor pathway generated rhythmic ventral root discharges and swimming movements. Our study bridges the gap between behavior and cellular neural mechanisms in vertebrates, identifying a specific subsystem within the CNS, dedicated to producing motor responses to olfactory inputs. PMID:21203583

  8. Neuropeptide receptors provide a signalling pathway for trigeminal modulation of olfactory transduction.

    PubMed

    Daiber, Philipp; Genovese, Federica; Schriever, Valentin A; Hummel, Thomas; Möhrlen, Frank; Frings, Stephan

    2013-02-01

    The mammalian olfactory epithelium contains olfactory receptor neurons and trigeminal sensory endings. The former mediate odor detection, the latter the detection of irritants. The two apparently parallel chemosensory systems are in reality interdependent in various well-documented ways. Psychophysical studies have shown that virtually all odorants can act as irritants, and that most irritants have an odor. Thus, the sensory perception of odorants and irritants is based on simultaneous input from the two systems. Moreover, functional interactions between the olfactory system and the trigeminal system exist on both peripheral and central levels. Here we examine the impact of trigeminal stimulation on the odor response of olfactory receptor neurons. Using an odorant with low trigeminal potency (phenylethyl alcohol) and a non-odorous irritant (CO(2) ), we have explored this interaction in psychophysical experiments with human subjects and in electroolfactogram (EOG) recordings from rats. We have demonstrated that simultaneous activation of the trigeminal system attenuates the perception of odor intensity and distorts the EOG response. On the molecular level, we have identified a route for this cross-modal interaction. The neuropeptide calcitonin-gene related peptide (CGRP), which is released from trigeminal sensory fibres upon irritant stimulation, inhibits the odor response of olfactory receptor neurons. CGRP receptors expressed by these neurons mediate this neuromodulatory effect. This study demonstrates a site of trigeminal-olfactory interaction in the periphery. It reveals a pathway for trigeminal impact on olfactory signal processing that influences odor perception. PMID:23205840

  9. The Olfactory Transcriptomes of Mice

    PubMed Central

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

    2014-01-01

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

  10. Olfactory maps, circuits and computations.

    PubMed

    Giessel, Andrew J; Datta, Sandeep Robert

    2014-02-01

    Sensory information in the visual, auditory and somatosensory systems is organized topographically, with key sensory features ordered in space across neural sheets. Despite the existence of a spatially stereotyped map of odor identity within the olfactory bulb, it is unclear whether the higher olfactory cortex uses topography to organize information about smells. Here, we review recent work on the anatomy, microcircuitry and neuromodulation of two higher-order olfactory areas: the piriform cortex and the olfactory tubercle. The piriform is an archicortical region with an extensive local associational network that constructs representations of odor identity. The olfactory tubercle is an extension of the ventral striatum that may use reward-based learning rules to encode odor valence. We argue that in contrast to brain circuits for other sensory modalities, both the piriform and the olfactory tubercle largely discard any topography present in the bulb and instead use distributive afferent connectivity, local learning rules and input from neuromodulatory centers to build behaviorally relevant representations of olfactory stimuli. PMID:24492088

  11. The olfactory transcriptomes of mice.

    PubMed

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

    2014-09-01

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

  12. Electrical responses and synaptic connections of giant serotonin-immunoreactive neurons in crayfish olfactory and accessory lobes.

    PubMed

    Sandeman, D C; Sandeman, R E

    1994-03-01

    Five pairs of identified 5HT-IR cells in the deutocerebrum of the crayfish Cherax are known to have their synaptic endings in the accessory and olfactory lobes. Two of these cells, one on each side of the brain, are significantly larger than the others. Dye fills of these "giant" cells reveal each to be an interneuron with its branches confined to, but distributed throughout, the olfactory and accessory lobes on the side of the brain ipsilateral to its cell body and with no branches to the contralateral side. Intracellular recordings from the giant cells were made while stimulating the olfactory afferents and tracts within the brain in an attempt to discover the inputs and outputs to the cells. Electrical stimulation of chemoreceptor sensilla on the outer branch of the antennule does not excite the giant 5HT neurons. Focal extracellular electrical stimulation of the olfactory globular tract containing the axons of projection neurons from the olfactory and accessory lobes produces excitatory synaptic potentials and action potentials in the giant cells. Focal extracellular electrical stimulation of the deutocerebral commissure, the axons of which terminate in the glomeruli of the accessory lobes, also results in excitation of the giant cells. We conclude that the input to the giant cells is via axons in the deutocerebral commissure and collaterals from the projection neurons, ending in the glomeruli of the accessory lobes. The output of the giant cells is to the olfactory lobes, where it may serve to modulate olfactory signals. PMID:8006219

  13. Assessment of olfactory function.

    PubMed

    Hummel, Thomas; Welge-Lüessen, Antje

    2006-01-01

    Numerous techniques are available for the investigation of chemosensory functions in humans. They include psychophysical measures of chemosensory function, e.g. odor identification, odor discrimination, odor thresholds, odor memory, and retronasal perception of odors. In order to assess changes related to the patients' quality of life or effects of qualitative olfactory dysfunction, questionnaires are being used. Measures relying to a lesser degree on the subjects' cooperation are e.g. chemosensory event-related potentials, odor-induced changes of the EEG, the electroolfactogram, imaging techniques, or measures of respiration. In a clinical context, however, psychophysical techniques are most frequently used, e.g. tests for odor identification, and odor thresholds. Interpretation of results from these measures is frequently supported by the assessment of chemosensory event-related potentials. Other techniques await further standardization before they will become useful in a clinical context. PMID:16733334

  14. Olfactory receptor signaling.

    PubMed

    Antunes, Gabriela; Simoes de Souza, Fabio Marques

    2016-01-01

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

  15. Nonlinear response speedup in bimodal visual-olfactory object identification

    PubMed Central

    Höchenberger, Richard; Busch, Niko A.; Ohla, Kathrin

    2015-01-01

    Multisensory processes are vital in the perception of our environment. In the evaluation of foodstuff, redundant sensory inputs not only assist the identification of edible and nutritious substances, but also help avoiding the ingestion of possibly hazardous substances. While it is known that the non-chemical senses interact already at early processing levels, it remains unclear whether the visual and olfactory senses exhibit comparable interaction effects. To address this question, we tested whether the perception of congruent bimodal visual-olfactory objects is facilitated compared to unimodal stimulation. We measured response times (RT) and accuracy during speeded object identification. The onset of the visual and olfactory constituents in bimodal trials was physically aligned in the first and perceptually aligned in the second experiment. We tested whether the data favored coactivation or parallel processing consistent with race models. A redundant-signals effect was observed for perceptually aligned redundant stimuli only, i.e., bimodal stimuli were identified faster than either of the unimodal components. Analysis of the RT distributions and accuracy data revealed that these observations could be explained by a race model. More specifically, visual and olfactory channels appeared to be operating in a parallel, positively dependent manner. While these results suggest the absence of early sensory interactions, future studies are needed to substantiate this interpretation. PMID:26483730

  16. Olfactory receptor response to CO2 in bullfrogs.

    PubMed

    Coates, E L; Ballam, G O

    1990-05-01

    In vivo electrophysiological recordings of olfactory receptor cells of the bullfrog (Rana catesbeiana) exhibit a receptor response to CO2 concentrations as low as 0.5%. The amplitude of the electroolfactogram (EOG) increased with an increase in the CO2 concentration delivered to the olfactory epithelium. Likewise, there was a significant increase in the decay time (time from 90 to 10% peak EOG amplitude) with an increase in CO2. The EOG rise time (time from 10 to 90% peak EOG amplitude) and the EOG response latency (time from beginning of CO2 pulse to beginning of EOG response) significantly decreased, whereas the plateau time (time from 90% rising phase to 90% falling phase of the peak EOG amplitude) was not significantly altered by an increase in CO2. These results indicate that low concentrations of CO2, below normal end expiratory CO2 concentrations, stimulate olfactory receptor cells. These results support our proposal that the ventilatory depression observed in response to upper airway CO2 in reptiles and amphibians is mediated by CO2-sensitive olfactory receptor cells. PMID:2110785

  17. Postnatal Experience Modulates Functional Properties of Mouse Olfactory Sensory Neurons

    PubMed Central

    He, Jiwei; Tian, Huikai; Lee, Anderson C.; Ma, Minghong

    2012-01-01

    Early experience considerably modulates the organization and function of all sensory systems. In the mammalian olfactory system, deprivation of the sensory inputs via neonatal, unilateral naris closure has been shown to induce structural, molecular, and functional changes from the olfactory epithelium to the olfactory bulb and cortex. However, it remains unknown how early experience shapes functional properties of individual olfactory sensory neurons (OSNs), the primary odor detectors in the nose. To address this question, we examined odorant response properties of mouse OSNs in both the closed and open nostril after four weeks of unilateral naris closure with age-matched untreated animals as control. Using patch-clamp technique on genetically-tagged OSNs with defined odorant receptors (ORs), we found that sensory deprivation increased the sensitivity of MOR23 neurons in the closed side while overexposure caused the opposite effect in the open side. We next analyzed the response properties including rise time, decay time, and adaptation induced by repeated stimulation in MOR23 and M71 neurons. Even though these two types of neurons showed distinct properties in dynamic range and response kinetics, sensory deprivation significantly slowed down the decay phase of odorant-induced transduction events in both types. Using western blotting and antibody staining, we confirmed upregulation of several signaling proteins in the closed side as compared with the open side. This study suggests that early experience modulates functional properties of OSNs, probably via modifying the signal transduction cascade. PMID:22703547

  18. Coding and transformations in the olfactory system.

    PubMed

    Uchida, Naoshige; Poo, Cindy; Haddad, Rafi

    2014-01-01

    How is sensory information represented in the brain? A long-standing debate in neural coding is whether and how timing of spikes conveys information to downstream neurons. Although we know that neurons in the olfactory bulb (OB) exhibit rich temporal dynamics, the functional relevance of temporal coding remains hotly debated. Recent recording experiments in awake behaving animals have elucidated highly organized temporal structures of activity in the OB. In addition, the analysis of neural circuits in the piriform cortex (PC) demonstrated the importance of not only OB afferent inputs but also intrinsic PC neural circuits in shaping odor responses. Furthermore, new experiments involving stimulation of the OB with specific temporal patterns allowed for testing the relevance of temporal codes. Together, these studies suggest that the relative timing of neuronal activity in the OB conveys odor information and that neural circuits in the PC possess various mechanisms to decode temporal patterns of OB input. PMID:24905594

  19. [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. PMID:21879170

  20. Activity-Induced Remodeling of Olfactory Bulb Microcircuits Revealed by Monosynaptic Tracing

    PubMed Central

    Arenkiel, Benjamin R.; Hasegawa, Hiroshi; Yi, Jason J.; Larsen, Rylan S.; Wallace, Michael L.; Philpot, Benjamin D.; Wang, Fan; Ehlers, Michael D.

    2011-01-01

    The continued addition of new neurons to mature olfactory circuits represents a remarkable mode of cellular and structural brain plasticity. However, the anatomical configuration of newly established circuits, the types and numbers of neurons that form new synaptic connections, and the effect of sensory experience on synaptic connectivity in the olfactory bulb remain poorly understood. Using in vivo electroporation and monosynaptic tracing, we show that postnatal-born granule cells form synaptic connections with centrifugal inputs and mitral/tufted cells in the mouse olfactory bulb. In addition, newly born granule cells receive extensive input from local inhibitory short axon cells, a poorly understood cell population. The connectivity of short axon cells shows clustered organization, and their synaptic input onto newborn granule cells dramatically and selectively expands with odor stimulation. Our findings suggest that sensory experience promotes the synaptic integration of new neurons into cell type-specific olfactory circuits. PMID:22216277

  1. Olfactory transduction in ciliated receptor neurons of the Cabinza grunt, Isacia conceptionis (Teleostei: Haemulidae).

    PubMed

    Schmachtenberg, Oliver; Bacigalupo, Juan

    2004-12-01

    The ciliated receptor neurons of fish olfactory organs are thought to transduce amino acids through a cAMP-dependent transduction pathway, but direct physiological evidence for this hypothesis remains scarce and is confined to catfish and trout. We investigated olfactory transduction in a marine fish, the Cabinza grunt Isacia conceptionis (Perciformes, Teleostei). The olfactory epithelium was characterized using light and electron microscopy, and isolated ciliated receptor neurons were recorded with the perforated patch-clamp technique. Cells were stimulated with puffer pipettes containing amino acid odourants, IBMX plus forskolin or 8 bromo-cAMP. All three stimuli triggered transient inward currents at a holding potential of -70 mV and responses with outward-rectifying current-voltage relationships. The characteristics of the transduction currents induced by each stimulus were similar across cells and indistinguishable within the same cell, supporting the hypothesis of a cAMP pathway mediating transduction of amino acids in ciliated olfactory receptor neurons. PMID:15610170

  2. 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

  3. 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

  4. Olfactory morphology and physiology of elasmobranchs.

    PubMed

    Meredith, Tricia L; Kajiura, Stephen M

    2010-10-15

    Elasmobranch fishes are thought to possess greater olfactory sensitivities than teleost fishes due in part to the large amount of epithelial surface area that comprises their olfactory organs; however, direct evidence correlating the size of the olfactory organ to olfactory sensitivity is lacking. This study examined the olfactory morphology and physiology of five distantly related elasmobranch species. Specifically, we quantified the number of lamellae and lamellar surface area (as if it were a flat sheet, not considering secondary lamellae) that comprise their olfactory organs. We also calculated the olfactory thresholds and relative effectiveness of amino acid odorants for each species. The olfactory organs varied in both the number of lamellae and lamellar surface area, which may be related to their general habitat, but neither correlated with olfactory threshold. Thresholds to amino acid odorants, major olfactory stimuli of all fishes, ranged from 10⁻⁹·⁰ to 10⁻⁶·⁹ mol l⁻¹, which indicates that these elasmobranch species demonstrate comparable thresholds with teleosts. In addition, the relative effectiveness of amino acid stimuli to the olfactory organ of elasmobranchs is similar to that previously described in teleosts with neutral amino acids eliciting significantly greater responses than others. Collectively, these results indicate parallels in olfactory physiology between these two groups of fishes. PMID:20889825

  5. Olfactory dysfunction in patients with multiple sclerosis.

    PubMed

    Li, Li-Min; Yang, Li-Na; Zhang, Lin-Jie; Fu, Ying; Li, Ting; Qi, Yuan; Wang, Jing; Zhang, Da-Qi; Zhang, Ningnannan; Liu, Jingchun; Yang, Li

    2016-06-15

    Association of changes in olfactory-related structures with olfactory function in patients with multiple sclerosis (MS) is not well understood. We used a T&T olfactometer test kit to evaluate olfactory function in 26 patients with MS and 26 age- and sex-matched healthy controls (HC). Then, Brain MRI were performed and olfactory-related structures were analyzed in these subjects. Olfactory detection and recognition threshold were significantly higher in the MS group, interestingly olfactory recognition threshold positively correlated with expanded disability status scale scores in these patients. Olfactory bulb (OB) volume reduced in patients with olfactory dysfunction (ODF). At the same time, reductions in gray matter (GM) volume were observed in the parahippocampal gyrus (PCG), amygdala, piriform cortex, and inferior frontal gyrus in patients with MS compared to HC. Atrophy of the PCG was more obvious in patients with ODF than patients without ODF and the PCG volume correlated with the olfactory recognition threshold, while no difference was found in fractional anisotropy values of tract-based spatial statistics analysis in the two groups. Olfactory function in patients with MS tends to become gradually more impaired with disability aggravation. Decreases in the volume of the OB and olfactory-related GM might provide valuable information about disease status in patients with MS with olfactory impairment. PMID:27206870

  6. Sniffing and Oxytocin: Effects on Olfactory Memories.

    PubMed

    Stoop, Ron

    2016-05-01

    In this issue of Neuron, Oettl et al. (2016) show how oxytocin can boost processing of olfactory information in female rats by a top-downregulation from the anterior olfactory nucleus onto the main olfactory bulb. As a result, interactions with juvenile conspecifics receive more attention and are longer memorized. PMID:27151635

  7. [Kinetics of Ca2+, NADH, and oxidized flavoproteins in the frog olfactory lining under the effect of odorants].

    PubMed

    Rudenko, Ia N; Bigdaĭ, E V; Samoĭlov, V O

    2007-01-01

    The kinetics of fluorescence of Ca(2+) - chlortertacyclin-cell membrane complex as well as of NADH and oxidized flavoproteins in receptor cells of the frog olfactory lining under the effect of odorants has been studied. Changes in the fluorescence of the olfactory lining upon stimulation by cineole and vanillin occurred more rapidly than under the effect of camphor and amyl alcohol. Differences in the kinetics of reactions of NADH and the Ca(2+)-CTC-CM complex to different odorants are apparently due to heterogeneity of molecular mechanisms associated with the involvement of different intracellular signal systems in the transduction of these odorants in the olfactory lining. In contrast to them, ammonia and beta3-mercaptoethanol penetrate into olfactory cells and inhibit the mitochondrial respiratory chain without the participation of second messengers. At the same time, the motor activity of olfactory cilia is depressed. PMID:17348402

  8. 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

  9. Monoallelic Expression of Olfactory Receptors

    PubMed Central

    Monahan, Kevin; Lomvardas, Stavros

    2016-01-01

    The sense of smell collects vital information about the environment by detecting a multitude of chemical odorants. Breadth and sensitivity are provided by a huge number of chemosensory receptor proteins, including more than 1,400 olfactory receptors (ORs). Organizing the sensory information generated by these receptors so that it can be processed and evaluated by the central nervous system is a major challenge. This challenge is overcome by monogenic and monoallelic expression of OR genes. The single OR expressed by each olfactory sensory neuron determines the neuron’s odor sensitivity and the axonal connections it will make to downstream neurons in the olfactory bulb. The expression of a single OR per neuron is accomplished by coupling a slow chromatin-mediated activation process to a fast negative-feedback signal that prevents activation of additional ORs. Singular OR activation is likely orchestrated by a network of interchromosomal enhancer interactions and large-scale changes in nuclear architecture. PMID:26359778

  10. Olfactory dysfunction in Alzheimer’s disease

    PubMed Central

    Zou, Yong-ming; Lu, Da; Liu, Li-ping; Zhang, Hui-hong; Zhou, Yu-ying

    2016-01-01

    Alzheimer’s disease (AD) is a common neurodegenerative disorder with the earliest clinical symptom of olfactory dysfunction, which is a potential clinical marker for AD severity and progression. However, many questions remain unanswered. This article reviews relevant research on olfactory dysfunction in AD and evaluates the predictive value of olfactory dysfunction for the epidemiological, pathophysiological, and clinical features of AD, as well as for the conversion of cognitive impairment to AD. We summarize problems of existing studies and provide a useful reference for further studies in AD olfactory dysfunction and for clinical applications of olfactory testing. PMID:27143888

  11. Both olfactory epithelial and vomeronasal inputs are essential for activation of the medial amygdala and preoptic neurons of male rats.

    PubMed

    Dhungel, S; Masaoka, M; Rai, D; Kondo, Y; Sakuma, Y

    2011-12-29

    Chemosensory inputs signaling volatile and nonvolatile molecules play a pivotal role in sexual and social behavior in rodents. We have demonstrated that olfactory preference in male rats, that is, attraction to receptive female odors, is regulated by the medial amygdala (MeA), the cortical amygdala (CoA), and the preoptic area (POA). In this paper, we investigated the involvement of two chemosensory organs, the olfactory epithelium (OE) and the vomeronasal organ (VNO), in olfactory preference and copulatory behavior in male rats. We found that olfactory preferences were impaired by zinc sulfate lesion of the OE but not surgical removal of the VNO. Copulatory behaviors, especially intromission frequency and ejaculation, were also suppressed by zinc sulfate treatment. Neuronal activation in the accessory olfactory bulb (AOB), the MeA, the CoA, and the POA was analyzed after stimulation by airborne odors or soiled bedding of estrous females using cFos immunohistochemistry. Although the OE and VNO belong to different neural systems, the main and accessory olfactory systems, respectively, both OE lesion and VNO removal almost equally suppressed the number of cFos-immunoreactive cells in those areas that regulate olfactory preference. These results suggest that signals received by the OE and VNO interact and converge in the early stage of olfactory processing, in the AOB and its targets, although they have distinct roles in the regulation of social behaviors. PMID:21983295

  12. Olfactory stimulatory with grapefruit and lavender oils change autonomic nerve activity and physiological function.

    PubMed

    Nagai, Katsuya; Niijima, Akira; Horii, Yuko; Shen, Jiao; Tanida, Mamoru

    2014-10-01

    This review summarizes the effects of olfactory stimulation with grapefruit and lavender oils on autonomic nerve activity and physiological function. Olfactory stimulation with the scent of grapefruit oil (GFO) increases the activity of sympathetic nerves that innervate white and brown adipose tissues, the adrenal glands, and the kidneys, decreases the activity of the gastric vagal nerve in rats and mice. This results in an increase in lipolysis, thermogenesis, and blood pressure, and a decrease in food intake. Olfactory stimulation with the scent of lavender oil (LVO) elicits the opposite changes in nerve activity and physiological variables. Olfactory stimulation with scent of limonene, a component of GFO, and linalool, a component of LVO, has similar effects to stimulation with GFO and LVO, respectively. The histamine H1-receptor antagonist, diphenhydramine, abolishes all GFO-induced changes in nerve activity and physiological variables, and the hitstamine H3-receptor antagonist, thioperamide, eliminates all LVO-induced changes. Lesions to the hypothalamic suprachiasmatic nucleus and anosmic treatment with ZnSO4 also abolish all GFO- and LVO-induced changes. These findings indicate that limonene and linalool might be the active substances in GFO and LVO, and suggest that the suprachiasmatic nucleus and histamine are involved in mediating the GFO- and LVO-induced changes in nerve activity and physiological variables. PMID:25002406

  13. Olfactory exploration: State of the art.

    PubMed

    Nguyen, D T; Rumeau, C; Gallet, P; Jankowski, R

    2016-04-01

    Olfactory disorders are fairly common in the general population. Exploration, on the other hand, is seldom performed by ENT specialists, even in reference centers. There may be three reasons for this: this particular sensory modality may seem unimportant to patients and/or physicians; available treatments may be underestimated, although admittedly much yet remains to be done; and olfactory exploration is not covered by the national health insurance scheme in France. Advances in research in recent decades have shed light on olfactory system functioning. At the same time, several techniques have been developed to allow maximally objective olfactory assessment, as olfactory disorder is sometimes the first sign of neurodegenerative pathology. Moreover, objective olfactory assessment may be needed in a medico-legal context. The present paper updates the techniques currently available for olfactory exploration. PMID:26384780

  14. Odorant-evoked potassium changes in the frog olfactory epithelium.

    PubMed

    Khayari, A; Math, F; Trotier, D

    1991-01-18

    Electroolfactogram (EOG) and extracellular potassium activity (aK) measurements were carried out in frog olfactory epithelia in vivo. Odorant-evoked changes in aK were characterized on the basis of depth profile analysis. Following an olfactory stimulation with butanol vapours, an increase in aK was measured in the mucus and the proximal part of the epithelium; this response started after the beginning of the EOG and was proportional to the amplitude of the latter. In the deeper part of the epithelium, the aK response had complex waveforms showing an initial K decrease which was suppressed by local application of ouabain, suggesting the existence of a pumping mechanism at this level. The results are discussed in terms of extracellular accumulation of K ions following neuroreceptor activation with respect to EOG generation theories. PMID:2015495

  15. Spontaneous and neurally evoked release of labelled noradrenaline from rabbit olfactory bulbs in vivo

    PubMed Central

    Brenells, Ann B.

    1974-01-01

    1. Rabbit olfactory bulbs were labelled with either [3H]noradrenaline (NA) and [14C]urea, or [14C]NA and [3H]inulin. The labelled substances released were collected by a modified cortical cup technique and estimated by liquid scintillation spectrometry. 2. In many experiments only total radioactivity originating from labelled NA was measured. In such cases the term NA radioactivity is used. 3. The spontaneous release of both NA radioactivity and marker radioactivity followed a multiphasic course. After 140 min the rate of efflux of NA radioactivity was significantly slower than that of the labelled marker. 4. Stimulation of one medial olfactory tract, one lateral olfactory tract or the surface of one bulb resulted in a selective increase in release of NA radioactivity. The size of the increase was dependent on the intensity, frequency and duration of stimulation. 5. There was a characteristic delay in the increased release of NA radioactivity following electrical stimulation. Acute lesioning of the olfactory tracts caudal to the stimulating electrode not only abolished this delay, but also resulted in a larger increase in release following stimulation. 6. The radioactivity attributable to unchanged NA was initially 91%, but decreased to 66% after 4½ hr of sample collection. Stimulation did not affect significantly the relative amounts of NA and metabolites released. 7. Replacement of calcium in the Krebs solution by magnesium did not affect measurably the spontaneous release of NA radioactivity. However, after 1 hr; stimulation failed to increase the efflux of NA radioactivity. 8. It is suggested that the results provide further evidence for a role for NA in synaptic transmission in the olfactory bulbs. PMID:4424430

  16. The olfactory receptor family album

    PubMed Central

    Crasto, Chiquito; Singer, Michael S; Shepherd, Gordon M

    2001-01-01

    Analysis of the human genome draft sequences has revealed a more complete portrait of the olfactory receptor gene repertoire in humans than was available previously. The new information provides a basis for deeper analysis of the functions of the receptors, and promises new insights into the evolutionary history of the family. PMID:11597337

  17. Olfactory adventures of elephantine pheromones.

    PubMed

    Rasmussen, L E; Lazar, J; Greenwood, D R

    2003-02-01

    Understanding the linkage between behaviour of mammals in their natural environment and the molecular basis of their sensory modalities presents challenges to biologists. Our olfactory investigations that involve the largest extant land mammal, the elephant, offer some clues of how these events mesh in sequence. Proboscideans have developed a sophisticatedly organized society and they rank with primates and cetaceans with respect to cognitive abilities. Our studies of discrete, quantifiable pheromone-elicited behaviours demonstrate that Asian elephants utilize their olfactory senses during fundamental, life-strategy decisions, including mate choice, female bonding and male hierarchical sorting. How biologically relevant odorants traverse mucous interfaces to interact with cognate odorant receptors remains a basic question in vertebrate olfaction. We have partially tracked the molecular odour reception trail of behaviourally distinct pheromones, ( Z )-7-dodecenyl acetate and frontalin (1,5-dimethyl-6,8-dioxabicyclo[3.2.1]octane), using approaches developed for insect studies and taking advantage of the extensive, highly mucoidal olfactory and vomeronasal systems that permit detailed investigations of pheromone-binding proteins. We have combined studies of quantifiable responses and behaviours with biochemical and biophysical investigations of the properties of protein-ligand complexes, their sequential pathways and associated protein-ligand fluxes. In the delineation of these sequential integrations of behavioural, biochemical and molecular events, we have discovered novel spatial and temporal adaptations in both the main olfactory and vomeronasal systems. PMID:12546671

  18. Angiotensinergic involvement in olfactory function

    SciTech Connect

    Speth, R.C.; Parker, J.L.; Wright, J.W.; Harding, J.W.

    1986-03-05

    The olfactory bulbs (OB) from Sprague-Dawley and Wistar-Kyoto rats were frozen and sectioned in a sagittal plane, 20 ..mu.. thick. Sections incubated with /sup 125/-Sar/sup 1/, Ile/sup 8/-AII indicated a high density of AII receptor binding sites in the external layers of the OB. Since the primary olfactory neurons synapse with the mitral cells in these layers, this suggests that AII may affect olfactory input to the OB. To test this hypothesis, male Sprague-Dawley rats, 9-12 weeks of age, n = 8, were administered 0.2 ml of 0.17 M ZnSO/sub 4/ into each nostril to lesion the primary olfactory neurons and their axon terminals in the OB. Rats treated with ZnSO/sub 4/ showed an impairment in their ability to find a buried food pellet, P = 0.041, Mann-Whitney test. Nine days post-treatment, the rats were sacrificed and AII receptors binding in homogenates of the OB was determined. There was a 23% increase (P < 0.05) in AII receptor density in the ZnSO/sub 4/ treated rat OB; it was correlated with the extent of the olfactory deficit, r/sub s/ = .91, Spearman Rank Order Test, P < .01. However, there was a 24% decrease in OB weight in the ZnSO/sub 4/ group, so the number of AII receptors per OB was unchanged. These data suggest that AII plays a role in olfaction. Localizing AII receptor changes within the OB by quantitative autoradiography will characterize the changes in AII receptor density caused by ZnSO/sub 4/.

  19. Olfactory abnormalities in temporal lobe epilepsy.

    PubMed

    Desai, M; Agadi, J B; Karthik, N; Praveenkumar, S; Netto, A B

    2015-10-01

    We studied olfactory function in a cohort of 25 temporal lobe epilepsy (TLE) patients and 25 healthy controls. Our objectives were to measure olfactory acuity in patients with right, left or bilateral TLE and compare them with age and sex matched controls, and to correlate olfactory acuity with duration of seizure, baseline seizure control and the number of drugs used. Olfactory impairment is common in neurological disorders and dysfunction of the temporo-limbic neural substrates involved in olfactory perception is noted in TLE. We measured olfactory acuity in 25 patients with TLE, nine with right, 10 with left and six with bilateral temporal lobe seizure activity, and compared them to the controls. Odor identification was assessed using the University of Pennsylvania Smell Identification Test (UPSIT) which is a 40 item olfactory test used to diagnose olfactory deficits. Our results showed that patients with TLE exhibited significant impairment in UPSIT performance compared to the controls. There was no significant difference in scores between the right and left TLE patients. The severity of olfactory impairment did not correlate with the duration of seizures, baseline seizure control and number of drugs used. We concluded that significant olfactory impairment is seen in both right and left TLE patients, unrelated to the duration and baseline frequency of seizures or drugs used. PMID:26149406

  20. Dynamic properties of Drosophila olfactory electroantennograms.

    PubMed

    Schuckel, Julia; Meisner, Shannon; Torkkeli, Päivi H; French, Andrew S

    2008-05-01

    Time-dependent properties of chemical signals are probably crucially important to many animals, but little is known about the dynamics of chemoreceptors. Behavioral evidence of dynamic sensitivity includes the control of moth flight by pheromone plume structure, and the ability of some blood-sucking insects to detect varying concentrations of carbon dioxide, possibly matched to host breathing rates. Measurement of chemoreceptor dynamics has been limited by the technical challenge of producing controlled, accurate modulation of olfactory and gustatory chemical concentrations over suitably wide ranges of amplitude and frequency. We used a new servo-controlled laminar flow system, combined with photoionization detection of surrogate tracer gas, to characterize electroantennograms (EAG) of Drosophila antennae during stimulation with fruit odorants or aggregation pheromone in air. Frequency response functions and coherence functions measured over a bandwidth of 0-100 Hz were well characterized by first-order low-pass linear filter functions. Filter time constant varied over almost a tenfold range, and was characteristic for each odorant, indicating that several dynamically different chemotransduction mechanisms are present. Pheromone response was delayed relative to fruit odors. Amplitude of response, and consequently signal-to-noise ratio, also varied consistently with different compounds. Accurate dynamic characterization promises to provide important new information about chemotransduction and odorant-stimulated behavior. PMID:18320197

  1. Noradrenergic Control of Odor Recognition in a Nonassociative Olfactory Learning Task in the Mouse

    ERIC Educational Resources Information Center

    Veyrac, Alexandra; Nguyen, Veronique; Marien, Marc; Didier, Anne; Jourdan, Francois

    2007-01-01

    The present study examined the influence of pharmacological modulations of the locus coeruleus noradrenergic system on odor recognition in the mouse. Mice exposed to a nonrewarded olfactory stimulation (training) were able to memorize this odor and to discriminate it from a new odor in a recall test performed 15 min later. At longer delays (30 or…

  2. Ghrelin Enhances Olfactory Sensitivity and Exploratory Sniffing in Rodents and Humans

    PubMed Central

    Tong, Jenny; Mannea, Erica; Aime, Pascaline; Pfluger, Paul T.; Yi, Chun-Xia; Castaneda, Tamara R.; Davis, Harold W.; Ren, Xueying; Pixley, Sarah; Benoit, Stephen; Julliard, Karyne; Woods, Stephen C; Horvath, Tamas L.; Sleeman, Mark M.; D’Alessio, David; Obici, Silvana; Frank, Robert; Tschöp, Matthias H.

    2011-01-01

    Olfaction is an integral part of feeding providing predictive cues that anticipate ingestion. Although olfactory function is modulated by factors such as prolonged fasting, the underlying neural mechanisms remain poorly understood. We recently identified ghrelin receptors in olfactory circuits in the brain. We therefore investigated the role of the appetite-stimulating hormone ghrelin in olfactory processing in rodents and humans, testing the hypothesis that ghrelin lowers olfactory detection thresholds and enhances exploratory sniffing, both being related to food-seeking. In rats, intracerebroventricular ghrelin decreased odor detection thresholds and increased sniffing frequency. In humans, systemic ghrelin infusions significantly enhanced sniff magnitudes in response to both food and non-food odorants and air in comparison to control saline infusions but did not affect the pleasantness ratings of odors. This is consistent with a specific effect on odor detection and not the hedonic value of odors. Collectively, our findings indicate that ghrelin stimulates exploratory sniffing and increases olfactory sensitivity, presumably enhancing the ability to locate, identify and select foods. This novel role is consistent with ghrelin’s overall function as a signal amplifier at the molecular interface between environmental and nutritional cues and neuroendocrine circuits controlling energy homeostasis. PMID:21490225

  3. 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

  4. 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

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

    PubMed

    Verbeurgt, Christophe; Wilkin, Françoise; 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

  6. 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

  7. Adenylate cyclase mediates olfactory transduction for a wide variety of odorants.

    PubMed Central

    Lowe, G; Nakamura, T; Gold, G H

    1989-01-01

    An odor-stimulated adenylate cyclase [ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1] is thought to mediate olfactory transduction in vertebrates. However, it is not known whether the adenylate cyclase serves this function for all odorants or for only certain classes of odorants. To investigate this question, we have compared the abilities of 35 odorants to stimulate the adenylate cyclase and to elicit an electrophysiological response. We report a strong positive correlation between the magnitude of adenylate cyclase stimulation and the summated electrical response of the olfactory epithelium (electro-olfactogram) evoked by individual odorants. We also show that the adenylate cyclase stimulator forskolin equally attenuates the electro-olfactogram response for all odorants tested. These data provide evidence that the adenylate cyclase mediates transduction for a wide variety of odorants. PMID:2787513

  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. PMID:26963317

  9. [Olfactory dysfunction : Update on diagnosis and treatment].

    PubMed

    Kühn, M; Abolmaali, N; Smitka, M; Podlesek, D; Hummel, T

    2016-07-01

    Olfactory dysfunction is a common disorder, particularly in elderly people. From the etiologic point of view, we distinguish between sinunasal and non-sinunasal causes of dysosmia. As an important early symptom of neurodegenerative disease, dysosmia is particularly relevant in the diagnosis of Parkinson's or Alzheimer's disease. In addition to complete ENT examination and olfactory testing, e.g., with "Sniffin' Sticks", modern imaging procedures, e. g. MRI, are becoming more and more important for diagnostics, prognosis, and treatment decisions. Olfactory testing in children needs to be adapted to their shorter concentration span and limited range of known olfactory stimuli. Depending on the etiology, olfactory training, antiphlogistic measures, and surgical procedures are most promising. In cases of intracranial causes of dysosmia, neurosurgeons should know and respect anatomic structures of the olfactory signal pathway, not least for long-term prognosis. PMID:27364339

  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. [Subjective assessment of olfactory function].

    PubMed

    Evren, Cenk; Yiğit, Volkan Bilge; Çınar, Fikret

    2015-01-01

    Of the five senses, the sense of smell is the most complex and unique in structure and organization. As diagnostic and therapeutic modalities are often underdeveloped, the sense of smell has been inadequately studied. Olfactory disorders may result from benign pathologies such as sinusitis as well as several diseases including Parkinson's disease, temporal lobe epilepsy, schizophrenia and Alzheimer disease. In this article, we aim to instruct the otorhinolaryngology specialists and residents regarding the tests which measure odor subjectively. PMID:25934410

  13. Cytokines and olfactory bulb microglia in response to bacterial challenge in the compromised primary olfactory pathway

    PubMed Central

    2012-01-01

    Background The primary olfactory pathway is a potential route through which microorganisms from the periphery could potentially access the central nervous system. Our previous studies demonstrated that if the olfactory epithelium was damaged, bacteria administered into the nasal cavity induced nitric oxide production in olfactory ensheathing cells. This study investigates the cytokine profile of olfactory tissues as a consequence of bacterial challenge and establishes whether or not the bacteria are able to reach the olfactory bulb in the central nervous system. Methods The olfactory epithelium of C57BL/6 mice was damaged by unilateral Triton X-100 nasal washing, and Staphylococcus aureus was administered ipsilaterally 4 days later. Olfactory mucosa and bulb were harvested 6 h, 24 h and 5 days after inoculation and their cytokine profile compared to control tissues. The fate of S. aureus and the response of bulbar microglia were examined using fluorescence microscopy and transmission electron microscopy. Results In the olfactory mucosa, administered S. aureus was present in supporting cells of the olfactory epithelium, and macrophages and olfactory nerve bundles in the lamina propria. Fluorescein isothiocyanate-conjugated S. aureus was observed within the olfactory mucosa and bulb 6 h after inoculation, but remained restricted to the peripheral layers up to 5 days later. At the 24-h time point, the level of interleukin-6 (IL-6) and tumour necrosis factor-α in the compromised olfactory tissues challenged with bacteria (12,466 ± 956 pg/ml and 552 ± 193 pg/ml, respectively) was significantly higher than that in compromised olfactory tissues alone (6,092 ± 1,403 pg/ml and 80 ± 2 pg/ml, respectively). Immunohistochemistry confirmed that IL-6 was present in several cell types including olfactory ensheathing cells and mitral cells of the olfactory bulb. Concurrently, there was a 4.4-, 4.5- and 2.8-fold increase in the density of i

  14. [Olfactory disorders – history, classification and implications].

    PubMed

    Welge-Lüssen, Antje

    2016-01-01

    Smell disorders are common and can be found in 3 – 5 % of the population under 65 years. With growing age these numbers increase up to 50 % and more. Qualitative disorders which cannot be measured are differentiated from quantitative disorders. Self-assessment of olfactory function is rather poor therefore olfactory testing is mandatory in cases of patients complaining about an olfactory disorder. Olfactory screening smell tests are available for orientation, however, for detailed testing or in cases of a pathological screening test an extensive psychophysical olfactory test battery such as the Sniffin' Sticks Test battery should be used. According to the result of the test battery olfactory function can be qualified as norm, hyp- or anosmic. Additionally, in cases of medicolegal questions, olfactory evoked potentials can be recorded. Smell disorders are classified according to the history, clinical and endoscopic examination of the nose. Imaging techniques such as magnetic resonance imaging (MRI) or computertomography may contribute to classify the disorder. Sinunasal olfactory disorders are considered to be the most common ones. If the etiology remains unclear a neurological examination has to be performed in order to rule out a concomitant neurodegenerative disease. Olfactory disorders in the elderly might have to be considered as a sign of a reduced regeneration capacity in general being depicted in an increase in overall mortality in affected subjects. PMID:27132644

  15. Human olfactory receptor responses to odorants

    PubMed Central

    Mainland, Joel D; Li, Yun R; Zhou, Ting; Liu, Wen Ling L; Matsunami, Hiroaki

    2015-01-01

    Although the human olfactory system is capable of discriminating a vast number of odors, we do not currently understand what chemical features are encoded by olfactory receptors. In large part this is due to a paucity of data in a search space covering the interactions of hundreds of receptors with billions of odorous molecules. Of the approximately 400 intact human odorant receptors, only 10% have a published ligand. Here we used a heterologous luciferase assay to screen 73 odorants against a clone library of 511 human olfactory receptors. This dataset will allow other researchers to interrogate the combinatorial nature of olfactory coding. PMID:25977809

  16. Activity-dependent genes in mouse olfactory sensory neurons.

    PubMed

    Fischl, Adrian M; Heron, Paula M; Stromberg, Arnold J; McClintock, Timothy S

    2014-06-01

    Activity-dependent survival of olfactory sensory neurons (OSNs) may allow animals to tune their olfactory systems to match their odor environment. Activity-dependent genes should play important roles in this process, motivating experiments to identify them. Both unilateral naris occlusion of mice for 6 days and genetic silencing of OSNs decreased S100A5, Lrrc3b, Kirrel2, Slc17a6, Rasgrp4, Pcp4l1, Plcxd3, and Kcnn2 while increasing Kirrel3. Naris occlusion also decreased Eml5, Ptprn, and Nphs1. OSN number was unchanged and stress-response mRNAs were unaffected after 6 days of naris occlusion. This leaves odor stimulation as the most likely cause of differential abundance of these mRNAs, but through a mechanism that is slow or indirect for most because 30-40 min of odor stimulation increased only 3 of 11 mRNAs decreased by naris occlusion: S100A5, Lrrc3b, and Kirrel2. Odorant receptor (OR) mRNAs were significantly more variable than the average mRNA, consistent with difficulty in reliably detecting changes in these mRNAs after 6 days of naris occlusion. One OR mRNA, Olfr855, was consistently decreased, however. These results suggest that the latency from the cessation of odor stimulation to effects on activity-dependent OSN survival must be a week or more in juvenile mice. PMID:24692514

  17. Activity-Dependent Genes in Mouse Olfactory Sensory Neurons

    PubMed Central

    2014-01-01

    Activity-dependent survival of olfactory sensory neurons (OSNs) may allow animals to tune their olfactory systems to match their odor environment. Activity-dependent genes should play important roles in this process, motivating experiments to identify them. Both unilateral naris occlusion of mice for 6 days and genetic silencing of OSNs decreased S100A5, Lrrc3b, Kirrel2, Slc17a6, Rasgrp4, Pcp4l1, Plcxd3, and Kcnn2 while increasing Kirrel3. Naris occlusion also decreased Eml5, Ptprn, and Nphs1. OSN number was unchanged and stress-response mRNAs were unaffected after 6 days of naris occlusion. This leaves odor stimulation as the most likely cause of differential abundance of these mRNAs, but through a mechanism that is slow or indirect for most because 30–40min of odor stimulation increased only 3 of 11 mRNAs decreased by naris occlusion: S100A5, Lrrc3b, and Kirrel2. Odorant receptor (OR) mRNAs were significantly more variable than the average mRNA, consistent with difficulty in reliably detecting changes in these mRNAs after 6 days of naris occlusion. One OR mRNA, Olfr855, was consistently decreased, however. These results suggest that the latency from the cessation of odor stimulation to effects on activity-dependent OSN survival must be a week or more in juvenile mice. PMID:24692514

  18. [Action of hyperoxia on the total electrical activity of the olfactory epithelium of the frog].

    PubMed

    Dmitriev, V V; Tarasov, E K; Lukash, A I

    1984-03-01

    Olfactory mucosa of the frog was stimulated with odours of amylacetat , butanol, alcohol, naphthalene, acetic acid in air and oxygen media under normal and high oxygen pressure (0.2 MPa and 0.7 MPa). The electroolfactogram (EOG) amplitude was higher in oxygen due, probably, to the olfactory mucosa oxygen saturation on concentration gradient as well as to the activation of processes related to the EOG generation. 0.2 MPa pressure as well as 0.7 MPa pressure applied for 60 min decreased the EOG amplitude. PMID:6724040

  19. Southern pine beetle: Olfactory receptor and behavior discrimination of enantiomers of the attractant pheromone frontalin

    SciTech Connect

    Payne, T.L.; Berisford, C.W.; Blum, M.S.; Dickens, J.C.; Hedden, R.L.; Mori, K.; Richerson, J.V.; Vite, J.P.; West, J.R.

    1982-05-01

    In a laboratory and field bioassays, the response of Dendroctonus frontalis was significantly greater to the mixture of (1S,55R)-(-)-frontalin and alpha-pinene than to (1R,5S)-(+)-frontalin and alpha-pinene. Electrophysiologrical studies revealed that antennal olfactory receptor cells were significantly more responsive to (1S,5R)-(-)-frontalin than to 1R,5S)-(+) -frontalin. Both enanitiomers stimulated the same olfactory cells which suggests that each cell possesses at least two types of enanitomer-specific acceptors.

  20. Analyzing responses of mouse olfactory sensory neurons using the air-phase electroolfactogram recording.

    PubMed

    Cygnar, Katherine D; Stephan, Aaron B; Zhao, Haiqing

    2010-01-01

    Animals depend on olfaction for many critical behaviors, such as finding food sources, avoiding predators, and identifying conspecifics for mating and other social interactions. The electroolfactogram (EOG) recording is an informative, easy to conduct, and reliable method to assay olfactory function at the level of the olfactory epithelium. Since the 1956 description of the EOG by Ottoson in frogs, the EOG recording has been applied in many vertebrates including salamanders, rabbits, rats, mice, and humans (reviewed by Scott and Scott-Johnson, 2002, ref. 2). The recent advances in genetic modification in mice have rekindled interest in recording the EOG for physiological characterization of olfactory function in knock-out and knock-in mice. EOG recordings have been successfully applied to demonstrate the central role of olfactory signal transduction components, and more recently to characterize the contribution of certain regulatory mechanisms to OSN responses. Odorant detection occurs at the surface of the olfactory epithelium on the cilia of OSNs, where a signal transduction cascade leads to opening of ion channels, generating a current that flows into the cilia and depolarizes the membrane. The EOG is the negative potential recorded extracellularly at the surface of the olfactory epithelium upon odorant stimulation, resulting from a summation of the potential changes caused by individual responsive OSNs in the recording field. Comparison of the amplitude and kinetics of the EOG thus provide valuable information about how genetic modification and other experimental manipulations influence the molecular signaling underlying the OSN response to odor. Here we describe an air-phase EOG recording on a preparation of mouse olfactory turbinates. Briefly, after sacrificing the mouse, the olfactory turbinates are exposed by bisecting the head along the midline and removing the septum. The turbinate preparation is then placed in the recording setup, and a recording

  1. Analyzing Responses of Mouse Olfactory Sensory Neurons Using the Air-phase Electroolfactogram Recording

    PubMed Central

    Cygnar, Katherine D.; Stephan, Aaron B.; Zhao, Haiqing

    2010-01-01

    Animals depend on olfaction for many critical behaviors, such as finding food sources, avoiding predators, and identifying conspecifics for mating and other social interactions. The electroolfactogram (EOG) recording is an informative, easy to conduct, and reliable method to assay olfactory function at the level of the olfactory epithelium. Since the 1956 description of the EOG by Ottoson in frogs1, the EOG recording has been applied in many vertebrates including salamanders, rabbits, rats, mice, and humans (reviewed by Scott and Scott-Johnson, 2002, ref. 2). The recent advances in genetic modification in mice have rekindled interest in recording the EOG for physiological characterization of olfactory function in knock-out and knock-in mice. EOG recordings have been successfully applied to demonstrate the central role of olfactory signal transduction components3-8, and more recently to characterize the contribution of certain regulatory mechanisms to OSN responses9-12. Odorant detection occurs at the surface of the olfactory epithelium on the cilia of OSNs, where a signal transduction cascade leads to opening of ion channels, generating a current that flows into the cilia and depolarizes the membrane13. The EOG is the negative potential recorded extracellularly at the surface of the olfactory epithelium upon odorant stimulation, resulting from a summation of the potential changes caused by individual responsive OSNs in the recording field2. Comparison of the amplitude and kinetics of the EOG thus provide valuable information about how genetic modification and other experimental manipulations influence the molecular signaling underlying the OSN response to odor. Here we describe an air-phase EOG recording on a preparation of mouse olfactory turbinates. Briefly, after sacrificing the mouse, the olfactory turbinates are exposed by bisecting the head along the midline and removing the septum. The turbinate preparation is then placed in the recording setup, and a

  2. Polysynaptic Potentiation at Different Levels of Rat Olfactory Pathways Following Learning

    PubMed Central

    Mouly, Anne Marie; Gervais, Rémi

    2002-01-01

    This study was aimed at investigating the consequences of learning on late polysynaptic components of evoked field potential signals recorded in parallel at different levels of the olfactory pathways. For this, evoked field potentials induced by electrical stimulation of the olfactory bulb were recorded simultaneously in the anterior piriform cortex, the posterior piriform cortex, the lateral entorhinal cortex, and the dentate gyrus. The different parameters of late components were measured in each site before and after completion of associative learning in anesthetized rats. In the learning task, rats were trained to associate electrical stimulation of one olfactory bulb electrode with the delivery of sucrose (positive reward) and stimulation of a second olfactory bulb electrode with the delivery of quinine (negative reward). In this way, stimulation of the same olfactory bulb electrodes used for inducing field potentials served as a discriminative cue in the learning paradigm. The data confirmed previous observation that learning was associated with a lowering in late-component-1 intensity of induction in the posterior piriform cortex. The use of simultaneous recording allowed us to further specify the consequences of learning on late-component distribution in the studied network. Indeed the data showed that whereas before learning, late component 1 was rather uniformly distributed among the recorded sites; following learning, its expression was facilitated preferentially in the posterior piriform cortex and lateral entorhinal cortex. Furthermore, learning was accompanied by the emergence of a new late component (late component 2), which occurred simultaneously in the four recording sites. The possible involvement of potentiation of polysynaptic components in recognition and/or consolidation processes will be discussed. PMID:11992017

  3. Calcium permeable AMPA receptors and autoreceptors in external tufted cells of rat olfactory bulb

    PubMed Central

    Ma, Jie; Lowe, Graeme

    2007-01-01

    Glomeruli are functional units of the olfactory bulb responsible for early processing of odor information encoded by single olfactory receptor genes. Glomerular neural circuitry includes numerous external tufted (ET) cells whose rhythmic burst firing may mediate synchronization of bulbar activity with the inhalation cycle. Bursting is entrained by glutamatergic input from olfactory nerve terminals, so specific properties of ionotropic glutamate receptors on ET cells are likely to be important determinants of olfactory processing. Particularly intriguing is recent evidence that α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptors of juxta-glomerular neurons may permeate calcium. This could provide a novel pathway for regulating ET cell signaling. We tested the hypothesis that ET cells express functional calcium-permeable AMPA receptors. In rat olfactory bulb slices, excitatory postsynaptic currents (EPSCs) in ET cells were evoked by olfactory nerve shock, and by uncaging glutamate. We found attenuation of AMPA/kainate EPSCs by 1-naphthyl acetyl-spermine (NAS), an open-channel blocker specific for calcium permeable AMPA receptors. Cyclothiazide strongly potentiated EPSCs, indicating a major contribution from AMPA receptors. The current-voltage (I-V) relation of uncaging EPSCs showed weak inward rectification which was lost after > ~ 10 min of whole-cell dialysis, and was absent in NAS. In kainate-stimulated slices, Co2+ ions permeated cells of the glomerular layer. Large AMPA EPSCs were accompanied by fluorescence signals in fluo-4 loaded cells, suggesting calcium permeation. Depolarizing pulses evoked slow tail currents with pharmacology consistent with involvement of calcium permeable AMPA autoreceptors. Tail currents were abolished by Cd2+ and NBQX, and were sensitive to NAS block. Glutamate autoreceptors were confirmed by uncaging intracellular calcium to evoke a large inward current. Our results provide evidence that calcium permeable AMPA

  4. 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

  5. Olfactory instruction for fear: neural system analysis

    PubMed Central

    Canteras, Newton S.; Pavesi, Eloisa; Carobrez, Antonio P.

    2015-01-01

    Different types of predator odors engage elements of the hypothalamic predator-responsive circuit, which has been largely investigated in studies using cat odor exposure. Studies using cat odor have led to detailed mapping of the neural sites involved in innate and contextual fear responses. Here, we reviewed three lines of work examining the dynamics of the neural systems that organize innate and learned fear responses to cat odor. In the first section, we explored the neural systems involved in innate fear responses and in the acquisition and expression of fear conditioning to cat odor, with a particular emphasis on the role of the dorsal premammillary nucleus (PMd) and the dorsolateral periaqueductal gray (PAGdl), which are key sites that influence innate fear and contextual conditioning. In the second section, we reviewed how chemical stimulation of the PMd and PAGdl may serve as a useful unconditioned stimulus in an olfactory fear conditioning paradigm; these experiments provide an interesting perspective for the understanding of learned fear to predator odor. Finally, in the third section, we explored the fact that neutral odors that acquire an aversive valence in a shock-paired conditioning paradigm may mimic predator odor and mobilize elements of the hypothalamic predator-responsive circuit. PMID:26300721

  6. Detection of explosives by olfactory sensory neurons.

    PubMed

    Corcelli, Angela; Lobasso, Simona; Lopalco, Patrizia; Dibattista, Michele; Araneda, Ricardo; Peterlin, Zita; Firestein, Stuart

    2010-03-15

    The response of olfactory sensory neurons to TNT and RDX as well as to some volatile organic compounds present in the vapors of antipersonnel landmines has been studied both in the pig and in the rat. GC/MS analyses of different plastic components of six different kinds of landmines were performed in order to identify the components of the "perfume" of mines. Studies on rat olfactory mucosa were carried out with electro-olfactogram and calcium imaging techniques, while changes in the cyclic adenosine monophosphate (cAMP) levels following exposure to odorants and explosives were used as a criterion to evaluate the interaction of TNT and RDX with olfactory receptors in a preparation of isolated pig olfactory cilia. These studies indicate that chemical compounds associated with explosives and explosive devices can activate mammalian olfactory receptors. PMID:19913995

  7. Olfactory Neuroblastoma: A Case Report.

    PubMed

    Olmo, Heather R; Stokes, Steven Marc; Foss, Robert D

    2016-06-01

    A 43-year-old female presented with persistent nasal congestion with intermittent epistaxis without resolution for the preceding 5 years. Clinical examination revealed a large pink rubbery mass, medial to the middle turbinate in the right nasal cavity extending to the choana. Radiographic images demonstrated a heterogeneously enhancing lobular soft tissue mass filling the right nasal cavity, causing lateral bowing of the right medial orbital wall and extending posteriorly to the right anterior ethmoid sinus. The clinical, radiographic, histologic, and immunohistochemical features of olfactory neuroblastoma are discussed. PMID:26316323

  8. 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...

  9. 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...

  10. 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.

  11. Neuromodulation of Olfactory Sensitivity in the Peripheral Olfactory Organs of the American Cockroach, Periplaneta americana

    PubMed Central

    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. PMID:24244739

  12. Odorant-regulated Ca2+ gradients in rat olfactory neurons.

    PubMed

    Restrepo, D; Okada, Y; Teeter, J H

    1993-11-01

    Olfactory neurons respond to odors with a change in conductance that mediates an influx of cations including Ca2+. The concomitant increase in [Cai] has been postulated to play a role in the adaptation to maintained odorant stimulation (Kurahashi, T., and T. Shibuya. 1990. Brain Research. 515:261-268. Kramer, R. H., and S. A. Siegelbaum. 1992. Neuron. 9:897-906. Zufall, F., G. M. Shepherd, and S. Firestein. 1991. Proceedings of the Royal Society of London, B. 246:225-230.) We have imaged the distribution of [Cai] in rat olfactory neurons (RON) using the Ca2+ indicator fura-2. A large percentage of the RON (42%, n = 35) responded to odorants with an increase in [Cai]. About half of the responding neurons displayed an increase in [Cai] at the apical end of the cell, but not at the soma. Moreover, in those cells that responded to odors with a standing [Cai] gradient, the gradient could be maintained for long periods of time (minutes) provided that the cells were continuously stimulated. In contrast, K(+)-induced depolarization elicited a more homogeneous increase in [Cai]. The spatially inhomogeneous increase in [Cai] elicited by odorants in some cells has important implications for the role of Ca2+ in adaptation because channels and enzymes regulated by Ca2+ will be affected differently depending on their location. PMID:8301263

  13. Preliminary Modeling and Simulation Study on Olfactory Cell Sensation

    NASA Astrophysics Data System (ADS)

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

    2009-05-01

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

  14. 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.

  15. The human olfactory receptor repertoire

    PubMed Central

    Zozulya, Sergey; Echeverri, Fernando; Nguyen, Trieu

    2001-01-01

    Background The mammalian olfactory apparatus is able to recognize and distinguish thousands of structurally diverse volatile chemicals. This chemosensory function is mediated by a very large family of seven-transmembrane olfactory (odorant) receptors encoded by approximately 1,000 genes, the majority of which are believed to be pseudogenes in humans. Results The strategy of our sequence database mining for full-length, functional candidate odorant receptor genes was based on the high overall sequence similarity and presence of a number of conserved sequence motifs in all known mammalian odorant receptors as well as the absence of introns in their coding sequences. We report here the identification and physical cloning of 347 putative human full-length odorant receptor genes. Comparative sequence analysis of the predicted gene products allowed us to identify and define a number of consensus sequence motifs and structural features of this vast family of receptors. A new nomenclature for human odorant receptors based on their chromosomal localization and phylogenetic analysis is proposed. We believe that these sequences represent the essentially complete repertoire of functional human odorant receptors. Conclusions The identification and cloning of all functional human odorant receptor genes is an important initial step in understanding receptor-ligand specificity and combinatorial encoding of odorant stimuli in human olfaction. PMID:11423007

  16. Neuropeptide Y in the olfactory microvillar cells.

    PubMed

    Montani, Giorgia; Tonelli, Simone; Elsaesser, Rebecca; Paysan, Jacques; Tirindelli, Roberto

    2006-07-01

    This paper examines a possible role of microvillar cells in coordinating cell death and regeneration of olfactory epithelial neurons. The olfactory neuroepithelium of mammals is a highly dynamic organ. Olfactory neurons periodically degenerate by apoptosis and as a consequence of chemical or physical damage. To compensate for this loss of cells, the olfactory epithelium maintains a lifelong ability to regenerate from a pool of resident multipotent stem cells. To assure functional continuity and histological integrity of the olfactory epithelium over a period of many decades, apoptosis and regeneration require to be precisely coordinated. Among the factors that have been implicated in mediating this regulation is the neuropeptide Y (NPY). Knockout mice that lack functional expression of this neurogenic peptide show defects in embryonic development of the olfactory epithelium and in its ability to regenerate in the adult. Here we show that, in postnatal olfactory epithelia, NPY is exclusively expressed by a specific population of microvillar cells. We previously characterized these cells as a novel type of putative chemosensory cells, which are provided with a phosphatidyl-inositol-mediated signal transduction cascade. Our findings allow for the first time to suggest that microvillar cells are involved in connecting apoptosis to neuronal regeneration by stimulus-induced release of NPY. PMID:16800866

  17. [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. PMID:24584010

  18. Lateralization of olfactory processing: differential impact of right and left temporal lobe epilepsies.

    PubMed

    Hudry, Julie; Ryvlin, Philippe; Saive, Anne-Lise; Ravel, Nadine; Plailly, Jane; Royet, Jean-Pierre

    2014-08-01

    Olfactory processes were reported to be lateralized. The purpose of this study was to further explore this phenomenon and investigate the effect of the hemispheric localization of epileptogenic foci on olfactory deficits in patients with temporal lobe epilepsy (TLE). Olfactory functioning was assessed in 61 patients and 60 healthy control (HC) subjects. The patients and HC subjects were asked to rate the intensity, pleasantness, familiarity, and edibility of 12 common odorants and then identify them. Stimulations were delivered monorhinally in the nostril ipsilateral to the epileptogenic focus in TLE and arbitrarily in either the left or the right nostril in the HC subjects. The results demonstrated that regardless of the side of stimulation, patients with TLE had reduced performance in all olfactory tasks compared with the HC subjects. With regard to the side of the epileptogenic focus, patients with left TLE judged odors as less pleasant and had more difficulty with identification than patients with right TLE, underlining a privileged role of the left hemisphere in the emotional and semantic processing of odors. Finally, irrespective of group, a tendency towards a right-nostril advantage for judging odor familiarity was found in agreement with a prominent role of the right hemisphere in odor memory processing. PMID:25048728

  19. 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

  20. Neuronal organization of olfactory bulb circuits

    PubMed Central

    Nagayama, Shin; Homma, Ryota; Imamura, Fumiaki

    2014-01-01

    Olfactory sensory neurons extend their axons solely to the olfactory bulb, which is dedicated to odor information processing. The olfactory bulb is divided into multiple layers, with different types of neurons found in each of the layers. Therefore, neurons in the olfactory bulb have conventionally been categorized based on the layers in which their cell bodies are found; namely, juxtaglomerular cells in the glomerular layer, tufted cells in the external plexiform layer, mitral cells in the mitral cell layer, and granule cells in the granule cell layer. More recently, numerous studies have revealed the heterogeneous nature of each of these cell types, allowing them to be further divided into subclasses based on differences in morphological, molecular, and electrophysiological properties. In addition, technical developments and advances have resulted in an increasing number of studies regarding cell types other than the conventionally categorized ones described above, including short-axon cells and adult-generated interneurons. Thus, the expanding diversity of cells in the olfactory bulb is now being acknowledged. However, our current understanding of olfactory bulb neuronal circuits is mostly based on the conventional and simplest classification of cell types. Few studies have taken neuronal diversity into account for understanding the function of the neuronal circuits in this region of the brain. This oversight may contribute to the roadblocks in developing more precise and accurate models of olfactory neuronal networks. The purpose of this review is therefore to discuss the expanse of existing work on neuronal diversity in the olfactory bulb up to this point, so as to provide an overall picture of the olfactory bulb circuit. PMID:25232305

  1. 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

  2. Contextual olfactory learning in cockroaches.

    PubMed

    Sato, Chihiro; Matsumoto, Yukihisa; Sakura, Midori; Mizunami, Makoto

    2006-04-01

    We investigated the capability of context-dependent olfactory learning in cockroaches. One group of cockroaches received training to associate peppermint odor (conditioning stimulus) with sucrose solution (appetitive unconditioned stimulus) and vanilla odor with saline solution under illumination and to associate peppermint with aversive unconditioned stimulus and vanilla with appetitive unconditioned stimulus in the dark. Another group received training with the opposite stimulus arrangement. Before training, both groups exhibited preference for vanilla over peppermint. After training, the former group preferred peppermint over vanilla under illumination but preferred vanilla over peppermint in the dark, and the latter group exhibited the opposite odor preference. We conclude that cockroaches are capable of disambiguating the meaning of conditioning stimuli according to visual context. PMID:16543825

  3. 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

  4. Methods to measure olfactory behavior in mice

    PubMed Central

    Zou, Junhui; Wang, Wenbin; Pan, Yung-Wei; Lu, Song; Xia, Zhengui

    2015-01-01

    Mice rely on the sense of olfaction to detect food sources, recognize social and mating partners, and avoid predators. Many behaviors of mice including learning and memory, social interaction, fear, and anxiety are closely associated with their function of olfaction, and behavior tasks designed to evaluate those brain functions may use odors as cues. Accurate assessment of olfaction is not only essential for the study of olfactory system but also critical for proper interpretation of various mouse behaviors especially learning and memory, emotionality and affect, and sociality. Here we describe a series of behavior experiments that offer multidimensional and quantitative assessments for mouse’s olfactory function, including olfactory habituation, discrimination, odor preference, odor detection sensitivity, and olfactory memory, to both social and nonsocial odors. PMID:25645244

  5. The Pig Olfactory Brain: A Primer.

    PubMed

    Brunjes, Peter C; Feldman, Sanford; Osterberg, Stephen K

    2016-06-01

    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

  6. Comparison of clinical tests of olfactory function.

    PubMed

    Reden, J; Draf, C; Frank, R A; Hummel, T

    2016-04-01

    To assess olfactory function, various measures are used in clinical routine. In this study, the Sniff Magnitude Test (SMT), a test considering the sniff response to an odor, was applied to patients with olfactory dysfunction (n = 49) and to a control group without subjective olfaction disorder (n = 21). For comparison, the validated "Sniffin' Sticks" test battery, a psychophysical olfactory test consisting of tests for phenyl ethyl alcohol odor threshold, odor discrimination, and odor identification was performed. Analyses indicated that the SMT showed significant differences between patients and controls (p = 0.003). Furthermore, results from the SMT and the "Sniffin' Sticks" correlated significantly (p < 0.001). In conclusion, the SMT appears to be a useful addition to the battery of available clinical tests to assess olfactory function. PMID:26050222

  7. Serotonin modulation of moth central olfactory neurons.

    PubMed

    Kloppenburg, Peter; Mercer, Alison R

    2008-01-01

    In the tobacco hornworm, Manduca sexta, 5-hydroxytryptamine (5HT) acting at the level of the antennal lobes contributes significantly to changing the moth's responsiveness to olfactory stimuli. 5HT targets K(+) conductances in the cells, increasing the excitability of central olfactory neurons and their responsiveness to olfactory cues. Effects of 5HT modulation are apparent not only at the single cell level, but also in the activity patterns of populations of neurons that convey olfactory information from antennal lobes to higher centers of the brain. Evidence suggests that 5HT-induced changes in activity within neural circuits of the antennal lobes might also drive structural plasticity, providing the basis for longer-term changes in antennal lobe function. PMID:18067443

  8. 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

  9. Olfactory specialization for perfume collection in male orchid bees.

    PubMed

    Mitko, Lukasz; Weber, Marjorie G; Ramirez, Santiago R; Hedenström, Erik; Wcislo, William T; Eltz, Thomas

    2016-05-15

    Insects rely on the olfactory system to detect a vast diversity of airborne molecules in their environment. Highly sensitive olfactory tuning is expected to evolve when detection of a particular chemical with great precision is required in the context of foraging and/or finding mates. Male neotropical orchid bees (Euglossini) collect odoriferous substances from multiple sources, store them in specialized tibial pouches and later expose them at display sites, presumably as mating signals to females. Previous analysis of tibial compounds among sympatric species revealed substantial chemical disparity in chemical composition among lineages with outstanding divergence between closely related species. Here, we tested whether specific perfume phenotypes coevolve with matching olfactory adaptations in male orchid bees to facilitate the location and harvest of species-specific perfume compounds. We conducted electroantennographic (EAG) measurements on males of 15 sympatric species in the genus Euglossa that were stimulated with 18 compounds present in variable proportions in male hind tibiae. Antennal response profiles were species-specific across all 15 species, but there was no conspicuous differentiation between closely related species. Instead, we found that the observed variation in EAG activity follows a Brownian motion model of trait evolution, where the probability of differentiation increases proportionally with lineage divergence time. However, we identified strong antennal responses for some chemicals that are present as major compounds in the perfume of the same species, thus suggesting that sensory specialization has occurred within multiple lineages. This sensory specialization was particularly apparent for semi-volatile molecules ('base note' compounds), thus supporting the idea that such compounds play an important role in chemical signaling of euglossine bees. Overall, our study found no close correspondence between antennal responses and behavioral

  10. Intraglomerular lateral inhibition promotes spike timing variability in principal neurons of the olfactory bulb.

    PubMed

    Najac, Marion; Sanz Diez, Alvaro; Kumar, Arvind; Benito, Nuria; Charpak, Serge; De Saint Jan, Didier

    2015-03-11

    The activity of mitral and tufted cells, the principal neurons of the olfactory bulb, is modulated by several classes of interneurons. Among them, diverse periglomerular (PG) cell types interact with the apical dendrites of mitral and tufted cells inside glomeruli at the first stage of olfactory processing. We used paired recording in olfactory bulb slices and two-photon targeted patch-clamp recording in vivo to characterize the properties and connections of a genetically identified population of PG cells expressing enhanced yellow fluorescent protein (EYFP) under the control of the Kv3.1 potassium channel promoter. Kv3.1-EYFP(+) PG cells are axonless and monoglomerular neurons that constitute ∼30% of all PG cells and include calbindin-expressing neurons. They respond to an olfactory nerve stimulation with a short barrage of excitatory inputs mediated by mitral, tufted, and external tufted cells, and, in turn, they indiscriminately release GABA onto principal neurons. They are activated by even the weakest olfactory nerve input or by the discharge of a single principal neuron in slices and at each respiration cycle in anesthetized mice. They participate in a fast-onset intraglomerular lateral inhibition between principal neurons from the same glomerulus, a circuit that reduces the firing rate and promotes spike timing variability in mitral cells. Recordings in other PG cell subtypes suggest that this pathway predominates in generating glomerular inhibition. Intraglomerular lateral inhibition may play a key role in olfactory processing by reducing the similarity of principal cells discharge in response to the same incoming input. PMID:25762678

  11. Olfactory bulb encoding during learning under anesthesia

    PubMed Central

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

    2014-01-01

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

  12. Phosphorylation of adenylyl cyclase III at serine1076 does not attenuate olfactory response in mice

    PubMed Central

    Cygnar, Katherine D; Collins, Sarah Ellen; Ferguson, Christopher H; Bodkin-Clarke, Chantal; Zhao, Haiqing

    2012-01-01

    Feedback inhibition of adenylyl cyclase III (ACIII) via Ca2+-induced phosphorylation has long been hypothesized to contribute to response termination and adaptation of olfactory sensory neurons (OSNs). To directly determine the functional significance of this feedback mechanism for olfaction in vivo, we genetically mutated serine1076 of ACIII, the only residue responsible for Ca2+-induced phosphorylation and inhibition of ACIII (Wei et al., 1996; Wei et al., 1998), to alanine in mice. Immunohistochemistry and Western blot analysis showed that the mutation affects neither the cilial localization nor the expression level of ACIII in OSNs. Electroolfactogram analysis showed no differences in the responses between wildtype and mutant mice to single-pulse odorant stimulations or in several stimulation paradigms for adaptation. These results suggest that phosphorylation of ACIII on serine1076 plays a far less important role in olfactory response attenuation than previously thought. PMID:23077041

  13. Phosphorylation of adenylyl cyclase III at serine1076 does not attenuate olfactory response in mice.

    PubMed

    Cygnar, Katherine D; Collins, Sarah Ellen; Ferguson, Christopher H; Bodkin-Clarke, Chantal; Zhao, Haiqing

    2012-10-17

    Feedback inhibition of adenylyl cyclase III (ACIII) via Ca(2+)-induced phosphorylation has long been hypothesized to contribute to response termination and adaptation of olfactory sensory neurons (OSNs). To directly determine the functional significance of this feedback mechanism for olfaction in vivo, we genetically mutated serine(1076) of ACIII, the only residue responsible for Ca(2+)-induced phosphorylation and inhibition of ACIII (Wei et al., 1996, 1998), to alanine in mice. Immunohistochemistry and Western blot analysis showed that the mutation affects neither the cilial localization nor the expression level of ACIII in OSNs. Electroolfactogram analysis showed no differences in the responses between wild-type and mutant mice to single-pulse odorant stimulations or in several stimulation paradigms for adaptation. These results suggest that phosphorylation of ACIII on serine(1076) plays a far less important role in olfactory response attenuation than previously thought. PMID:23077041

  14. Cortical feedback control of olfactory bulb circuits.

    PubMed

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

    2012-12-20

    Olfactory cortex pyramidal cells integrate sensory input from olfactory bulb mitral and tufted (M/T) cells and project axons back to the bulb. However, the impact of cortical feedback projections on olfactory bulb circuits is unclear. Here, we selectively express channelrhodopsin-2 in olfactory cortex pyramidal cells and show that cortical feedback projections excite diverse populations of bulb interneurons. Activation of cortical fibers directly excites GABAergic granule cells, which in turn inhibit M/T cells. However, we show that cortical inputs preferentially target short axon cells that drive feedforward inhibition of granule cells. In vivo, activation of olfactory cortex that only weakly affects spontaneous M/T cell firing strongly gates odor-evoked M/T cell responses: cortical activity suppresses odor-evoked excitation and enhances odor-evoked inhibition. Together, these results indicate that although cortical projections have diverse actions on olfactory bulb microcircuits, the net effect of cortical feedback on M/T cells is an amplification of odor-evoked inhibition. PMID:23259951

  15. Cholinergic microvillous cells in the mouse main olfactory epithelium and effect of acetylcholine on olfactory sensory neurons and supporting cells

    PubMed Central

    Ogura, Tatsuya; Szebenyi, Steven A.; Krosnowski, Kurt; Sathyanesan, Aaron; Jackson, Jacqueline

    2011-01-01

    The mammalian olfactory epithelium is made up of ciliated olfactory sensory neurons (OSNs), supporting cells, basal cells, and microvillous cells. Previously, we reported that a population of nonneuronal microvillous cells expresses transient receptor potential channel M5 (TRPM5). Using transgenic mice and immunocytochemical labeling, we identify that these cells are cholinergic, expressing the signature markers of choline acetyltransferase (ChAT) and the vesicular acetylcholine transporter. This result suggests that acetylcholine (ACh) can be synthesized and released locally to modulate activities of neighboring supporting cells and OSNs. In Ca2+ imaging experiments, ACh induced increases in intracellular Ca2+ levels in 78% of isolated supporting cells tested in a concentration-dependent manner. Atropine, a muscarinic ACh receptor (mAChR) antagonist suppressed the ACh responses. In contrast, ACh did not induce or potentiate Ca2+ increases in OSNs. Instead ACh suppressed the Ca2+ increases induced by the adenylyl cyclase activator forskolin in some OSNs. Supporting these results, we found differential expression of mAChR subtypes in supporting cells and OSNs using subtype-specific antibodies against M1 through M5 mAChRs. Furthermore, we found that various chemicals, bacterial lysate, and cold saline induced Ca2+ increases in TRPM5/ChAT-expressing microvillous cells. Taken together, our data suggest that TRPM5/ChAT-expressing microvillous cells react to certain chemical or thermal stimuli and release ACh to modulate activities of neighboring supporting cells and OSNs via mAChRs. Our studies reveal an intrinsic and potentially potent mechanism linking external stimulation to cholinergic modulation of activities in the olfactory epithelium. PMID:21676931

  16. Signal transduction for taurocholic acid in the olfactory system of Atlantic salmon.

    PubMed

    Lo, Y H; Bellis, S L; Cheng, L J; Pang, J; Bradley, T M; Rhoads, D E

    1994-10-01

    Conjugated bile acids such as taurocholic acid (TChA) are potent olfactory stimuli for Atlantic salmon (Salmo salar). A plasma membrane rich fraction was derived from salmon olfactory rosettes and used to investigate TChA signal transduction and receptor binding. In the presence of GTP gamma S, TChA caused dose-dependent stimulation of phosphatidylinositol 4,5-bisphosphate (PIP2) breakdown, half maximal at less than 10(-7) M TChA. Stimulation of PIP2 breakdown by TChA required GTP gamma S, was blocked by GDP beta S, and was mimicked by A1F4-, consistent with a G protein requirement. A1F4- and Ca2+ stimulated breakdown of PIP2, but not phosphatidylcholine, arguing against a non-specific lipase activation. Stimulation of PIP2 breakdown by TChA was maximal at low Ca2+ concentration, < or = 10 nM. Conventional binding analysis with 3H-TChA was inconclusive due to a high degree of non-specific binding and to lack of tissue specificity expected for an olfactory receptor. Analysis of odorant amino acid binding indicated possible interaction of TChA with a putative acidic amino acid receptor but no interaction of TChA with a putative neutral amino acid receptor. We conclude that olfactory discrimination between amino acids and bile acids occurs in part at the receptor level while both classes of odors appear to use the same signal transduction mechanism, G protein mediated activation of phosphoinositide specific phospholipase C (PLC). PMID:7881971

  17. Olfactory contributions to dehydration-induced anorexia in weanling rats.

    PubMed

    Bruno, J P; Hall, W G

    1982-11-01

    By 20 days of age, dehydration produces a clear anorexia, even though weanling rats have had only limited feeding and drinking experience. Their lack of ingestive experience makes weanlings good subjects for studying the physiological mechanisms subserving anorexic phenomena because learned contributions are unlikely to add significant complications. Twenty-day-old rats dehydrated by hypertonic saline injection were anorexic when offered milk or solid food (rat chow), but not when offered sucrose solutions (Experiment I). However, when the scent of almond was associated with sucrose solutions, or with water, intake of these solutions was depressed by dehydration (Experiment II). Thus for dehydrated rats, olfactory stimulation may help produce dehydration-induced anorexia. Making rats anosmic by intransal lavage with ZnSO4 (Experiment III) eliminated the anorexia to almond-scented water and partially eliminated that to milk. For these fluids, an odor cue seems a requirement for the occurrence of dehydration-anorexia. In Experiment IV, we found that dehydration-anorexia did not occur when milk was infused directly into pups' mouths. This finding suggests that the inhibitory process mediating dehydration-anorexia influences the approach to food and not the actual consumatory response that occurs once food is in the mouth. The inhibition of feeding produced by dehydration, therefore, may depend largely on olfactory cues, and seems to operate at a distance, as rats locate and approach food. PMID:7152117

  18. Chemosensory stimulation during sleep - Arousal responses to gustatory stimulation.

    PubMed

    Stuck, B A; Moutsis, T T; Bingel, U; Sommer, J U

    2016-05-13

    The processing of nociceptive, visual, vibrotactile, thermal and acoustic stimuli during sleep has been extensively investigated in the past. Recently, interest has focused on the impact of olfactory stimulation on sleep. In contrast to all other sensory systems, olfactory stimulation does not lead to an increased arousal frequency, regardless of hedonicity and concentration. The impact of the second chemosensory system, gustation, on sleep however has not been investigated to date. Twenty-one normosmic and normogeusic volunteers of both genders, aged 19-33 years, participated in the trial. Stimulation was performed with a gustometer using the following aqueous solutions: saccharose 20% (sweet), sodium chloride (NaCl) 7.5% (salty), citrate 5% (sour), and quinine 0.02% (bitter). A tasteless solution was used as negative control. Capsaicin, a strong trigeminal stimulus, served as positive control. Primary outcome was arousal frequency per stimulus in each sleep stage, as assessed with polysomnography. The frequency of arousals decreased in deeper sleep stages (N1: 211 arousals of 333 stimuli=63%, N2: 676/2728=25%, N3: 43/1378=3%, REM: 57/1010=6%). Statistically significant differences in terms of arousal frequency were found in N2 between the negative control and NaCl 100 μl (p<0.001), saccharose 100 μl, citrate 50 μl & 100 μl, and quinine 100 μl (p<0.05). Capsaicin led to complete awakenings in 94% of stimuli (30/32). These results demonstrate that gustatory stimulation during sleep induces arousals depending on stimulus intensity and sleep stage, which is different to olfactory stimulation and may be related to differences in central processing of the two chemosensory systems. PMID:26921652

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

    PubMed Central

    Jung, Yong Gi; Lane, Andrew P.

    2016-01-01

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

  20. Neuropeptide Y Enhances Olfactory Mucosa Responses to Odorant in Hungry Rats

    PubMed Central

    Negroni, Julia; Meunier, Nicolas; Monnerie, Régine; Salesse, Roland; Baly, Christine; Caillol, Monique; Congar, Patrice

    2012-01-01

    Neuropeptide Y (NPY) plays an important role in regulating appetite and hunger in vertebrates. In the hypothalamus, NPY stimulates food intake under the control of the nutritional status. Previous studies have shown the presence of NPY and receptors in rodent olfactory system, and suggested a neuroproliferative role. Interestingly, NPY was also shown to directly modulate olfactory responses evoked by a food-related odorant in hungry axolotls. We have recently demonstrated that another nutritional cue, insulin, modulates the odorant responses of the rat olfactory mucosa (OM). Therefore, the aim of the present study was to investigate the potential effect of NPY on rat OM responses to odorants, in relation to the animal's nutritional state. We measured the potential NPY modulation of OM responses to odorant, using electro-olfactogram (EOG) recordings, in fed and fasted adult rats. NPY application significantly and transiently increased EOG amplitudes in fasted but not in fed rats. The effects of specific NPY-receptor agonists were similarly quantified, showing that NPY operated mainly through Y1 receptors. These receptors appeared as heterogeneously expressed by olfactory neurons in the OM, and western blot analysis showed that they were overexpressed in fasted rats. These data provide the first evidence that NPY modulates the initial events of odorant detection in the rat OM. Because this modulation depends on the nutritional status of the animal, and is ascribed to NPY, the most potent orexigenic peptide in the central nervous system, it evidences a strong supplementary physiological link between olfaction and nutritional processes. PMID:23024812

  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. PMID:19711087

  2. Neuropeptide F neurons modulate sugar reward during associative olfactory learning of Drosophila larvae.

    PubMed

    Rohwedder, Astrid; Selcho, Mareike; Chassot, Bérénice; Thum, Andreas S

    2015-12-15

    All organisms continuously have to adapt their behavior according to changes in the environment in order to survive. Experience-driven changes in behavior are usually mediated and maintained by modifications in signaling within defined brain circuits. Given the simplicity of the larval brain of Drosophila and its experimental accessibility on the genetic and behavioral level, we analyzed if Drosophila neuropeptide F (dNPF) neurons are involved in classical olfactory conditioning. dNPF is an ortholog of the mammalian neuropeptide Y, a highly conserved neuromodulator that stimulates food-seeking behavior. We provide a comprehensive anatomical analysis of the dNPF neurons on the single-cell level. We demonstrate that artificial activation of dNPF neurons inhibits appetitive olfactory learning by modulating the sugar reward signal during acquisition. No effect is detectable for the retrieval of an established appetitive olfactory memory. The modulatory effect is based on the joint action of three distinct cell types that, if tested on the single-cell level, inhibit and invert the conditioned behavior. Taken together, our work describes anatomically and functionally a new part of the sugar reinforcement signaling pathway for classical olfactory conditioning in Drosophila larvae. PMID:26234537

  3. A specific area of olfactory cortex involved in stress hormone responses to predator odours.

    PubMed

    Kondoh, Kunio; Lu, Zhonghua; Ye, Xiaolan; Olson, David P; Lowell, Bradford B; Buck, Linda B

    2016-04-01

    Instinctive reactions to danger are critical to the perpetuation of species and are observed throughout the animal kingdom. The scent of predators induces an instinctive fear response in mice that includes behavioural changes, as well as a surge in blood stress hormones that mobilizes multiple body systems to escape impending danger. How the olfactory system routes predator signals detected in the nose to achieve these effects is unknown. Here we identify a specific area of the olfactory cortex in mice that induces stress hormone responses to volatile predator odours. Using monosynaptic and polysynaptic viral tracers, we found that multiple olfactory cortical areas transmit signals to hypothalamic corticotropin-releasing hormone (CRH) neurons, which control stress hormone levels. However, only one minor cortical area, the amygdalo-piriform transition area (AmPir), contained neurons upstream of CRH neurons that were activated by volatile predator odours. Chemogenetic stimulation of AmPir activated CRH neurons and induced an increase in blood stress hormones, mimicking an instinctive fear response. Moreover, chemogenetic silencing of AmPir markedly reduced the stress hormone response to predator odours without affecting a fear behaviour. These findings suggest that AmPir, a small area comprising <5% of the olfactory cortex, plays a key part in the hormonal component of the instinctive fear response to volatile predator scents. PMID:27001694

  4. Similar rate of information transfer on stimulus intensity in accessory and main olfactory bulb output neurons.

    PubMed

    Noguchi, Tomohiro; Sasajima, Hitoshi; Miyazono, Sadaharu; Kashiwayanagi, Makoto

    2014-07-25

    Recently, evidence has accumulated that the vomeronasal system cooperates with the main olfactory system to process volatile cues that regulate the animal's behavior. This is contradictory to the traditional view that the vomeronasal system is quite different from the main olfactory system in the time scale of information processing. Particularly, the firing rate of mitral/tufted cells in the accessory olfactory bulb (MTAOB) is known to be significantly lower than that of mitral cells in the main olfactory bulb (MCMOB). To address this question of whether the low-frequency firing in MTAOB carries less information than the high-frequency firing in MCMOB in the early stages of stimulation, we compared MTAOB and MCMOB for their firing mechanisms and information transfer characteristics. A model computation demonstrated that the inherent channel kinetics of MTAOB was responsible for their firing at a lower frequency than MCMOB. Nevertheless, our analysis suggested that MTAOB were comparable to MCMOB in both the amount and speed of information transfer about depolarizing current intensity immediately after current injection onset (<200ms). Our results support a hypothesis of simultaneous processing of common cues in both systems. PMID:24909616

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

    PubMed

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

    2015-05-18

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

  6. 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)

  7. Peripheral olfactory signaling in insects

    PubMed Central

    Suh, Eunho; Bohbot, Jonathan; Zwiebel, Laurence J.

    2014-01-01

    Olfactory signaling is a crucial component in the life history of insects. The development of precise and parallel mechanisms to analyze the tremendous amount of chemical information from the environment and other sources has been essential to their evolutionary success. Considerable progress has been made in the study of insect olfaction fueled by bioinformatics- based utilization of genomics along with rapid advances in functional analyses. Here we review recent progress in our rapidly emerging understanding of insect peripheral sensory reception and signal transduction. These studies reveal that the nearly unlimited chemical space insects encounter is covered by distinct chemosensory receptor repertoires that are generally derived by species-specific, rapid gene gain and loss, reflecting the evolutionary consequences of adaptation to meet their specific biological needs. While diverse molecular mechanisms have been put forth, often in the context of controversial models, the characterization of the ubiquitous, highly conserved and insect-specific Orco odorant receptor co-receptor has opened the door to the design and development of novel insect control methods to target agricultural pests, disease vectors and even nuisance insects. PMID:25584200

  8. 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

  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. Investigation of breathing parameters during odor perception and olfactory imagery.

    PubMed

    Kleemann, A M; Kopietz, R; Albrecht, J; Schöpf, V; Pollatos, O; Schreder, T; May, J; Linn, J; Brückmann, H; Wiesmann, M

    2009-01-01

    Compared with visual and auditory imagery, little is known about olfactory imagery. There is evidence that respiration may be altered by both olfactory perception and olfactory imagery. In order to investigate this relationship, breathing parameters (respiratory minute volume, respiratory amplitude, and breathing rate) in human subjects during olfactory perception and olfactory imagery were investigated. Fifty-six subjects having normal olfactory function were tested. Nasal respiration was measured using a respiratory pressure sensor. Using an experimental block design, we alternately presented odors or asked the subjects to imagine a given smell. Four different pleasant odors were used: banana, rose, coffee, and lemon odor. We detected a significant increase in respiratory minute volume between olfactory perception and the baseline condition as well as between olfactory imagery and baseline condition. Additionally we found significant differences in the respiratory amplitude between imagery and baseline condition and between odor and imagery condition. Differences in the breathing rate between olfactory perception, olfactory imagery, and baseline were not statistically significant. We conclude from our results that olfactory perception and olfactory imagery both have effects on the human respiratory profile and that these effects are based on a common underlying mechanism. PMID:18701432

  11. Individual olfactory perception reveals meaningful nonolfactory genetic information

    PubMed Central

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

    2015-01-01

    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. PMID:26100865

  12. The Na+/Ca2+ exchanger NCKX4 governs termination and adaptation of the mammalian olfactory response

    PubMed Central

    Stephan, Aaron B.; Tobochnik, Steven; Dibattista, Michele; Wall, Crystal M.; Reisert, Johannes; Zhao, Haiqing

    2011-01-01

    Sensory perception requires accurate encoding of stimulus information by sensory receptor cells. Here, we identify NCKX4, a potassium – dependent Na+/Ca2+ exchanger, to be necessary for rapid response termination and proper adaptation of vertebrate olfactory sensory neurons (OSNs). Nckx4−/− mouse OSNs display substantially prolonged responses and stronger adaptation. Single – cell electrophysiological analyses demonstrate that the majority of Na+ – dependent Ca2+ exchange in OSNs relevant to sensory transduction is due to NCKX4 and that Nckx4−/− mouse OSNs are deficient in encoding action potentials upon repeated stimulation. Olfactory – specific Nckx4 knockout mice have a reduced ability to locate an odorous source and lower body weights. These results establish the role of NCKX4 in shaping olfactory responses and suggest that rapid response termination and proper adaptation of peripheral sensory receptor cells tune the sensory system for optimal perception. PMID:22057188

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

    PubMed

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

    2013-11-15

    The mammalian olfactory system has merits of higher sensitivity, selectivity and faster response than current electronic nose system based on chemical sensor array. It is advanced and feasible to detect and discriminate odors by mammalian olfactory system. The purpose of this study is to develop a novel bioelectronic nose based on the brain-machine interface (BMI) technology for odor detection by in vivo electrophysiological measurements of olfactory bulb. In this work, extracellular potentials of mitral/tufted (M/T) cells in olfactory bulb (OB) were recorded by implanted 16-channel microwire electrode arrays. The odor-evoked response signals were analyzed. We found that neural activities of different neurons showed visible different firing patterns both in temporal features and rate features when stimulated by different small molecular odorants. The detection low limit is below 1 ppm for some specific odors. Odors were classified by an algorithm based on population vector similarity and support vector machine (SVM). The results suggested that the novel bioelectonic nose was sensitive to odorant stimuli. The best classifying accuracy was up to 95%. With the development of the BMI and olfactory decoding methods, we believe that this system will represent emerging and promising platforms for wide applications in medical diagnosis and security fields. PMID:23774163

  14. Comparison of olfactory receptor (EOG) and bulbar (EEG) responses to amino acids in the catfish, Ictalurus punctatus.

    PubMed

    Byrd, R P; Caprio, J

    1982-10-01

    The olfactory bulb electroencephalogram (EEG) has been used as a method to imply receptor events12,13. However, experiments to correlate olfactory receptor and bulbar EEG activity in the same species of fish has not been performed. Reported here is the comparison between the simultaneously recorded receptor electroolfactogram (EOG) and the bulbar EEG in the channel catfish, Ictalurus punctatus. With amino acid stimulation of the olfactory mucosa, both the EOG and EEG exhibited an initial phasic response followed by a tonic level maintained throughout the stimulus duration. The relative magnitude of the tonic EEG activity (tonic level/phasic response), however, was significantly less than that for the EOG. Both EOG and integrated EEG responses increased exponentially with logarithmic increase in stimulus concentration from threshold to 10(-3) M. Estimated electrophysiological thresholds for 5 amino acids tested determined by both recording methods did not differ significantly and averaged 10(-9.3) +/- 0.2 M for the EOG and 10(-9.1) +/- 0.2 M for the EEG. There was also a significant correlation between the order of relative effectiveness for 11 amino acids determined by EOG and EEG recordings. These results indicate that in the catfish the olfactory bulb EEG is an indicator of olfactory receptor activity. PMID:7139300

  15. Cortical metabolic arrangement during olfactory processing: proposal for a 18F FDG PET/CT methodological approach.

    PubMed

    Micarelli, Alessandro; Pagani, Marco; Chiaravalloti, Agostino; Bruno, Ernesto; Pavone, Isabella; Candidi, Matteo; Danieli, Roberta; Schillaci, Orazio; Alessandrini, Marco

    2014-10-01

    The aim of this article is to investigate the cortical metabolic arrangements in olfactory processing by using F fluorodeoxyglucose (FDG) positron emission tomography/computed tomography.Twenty-six normosmic individuals (14 women and 12 men; mean age 46.7 ± 10 years) were exposed to a neutral olfactory condition (NC) and, after 1 month, to a pure olfactory condition (OC) in a relatively ecological environment, that is, outside the scanner. All the subjects were injected with 185-210 megabecquerel of F FDG during both stimulations. Statistical parametric mapping version 2 was used in order to assess differences between NC and OC.As a result, we found a significant higher glucose consumption during OC in the cuneus, lingual, and parahippocampal gyri, mainly in the left hemisphere. During NC, our results show a relative higher glucose metabolism in the left superior, inferior, middle, medial frontal, and orbital gyri as well as in the anterior cingulate cortex.The present investigation, performed with a widely available functional imaging clinical tool, may help to better understand the neural responses associated to olfactory processing in healthy individuals and in patients with olfactory disorders by acquiring data in an ecologic, noise-free, and resting condition in which possible cerebral activations related to unwanted attentional processes might be avoided. PMID:25340494

  16. Cortical Metabolic Arrangement During Olfactory Processing: Proposal for a 18F FDG PET/CT Methodological Approach

    PubMed Central

    Micarelli, Alessandro; Pagani, Marco; Chiaravalloti, Agostino; Bruno, Ernesto; Pavone, Isabella; Candidi, Matteo; Danieli, Roberta; Schillaci, Orazio; Alessandrini, Marco

    2014-01-01

    Abstract The aim of this article is to investigate the cortical metabolic arrangements in olfactory processing by using 18F fluorodeoxyglucose (FDG) positron emission tomography/computed tomography. Twenty-six normosmic individuals (14 women and 12 men; mean age 46.7 ± 10 years) were exposed to a neutral olfactory condition (NC) and, after 1 month, to a pure olfactory condition (OC) in a relatively ecological environment, that is, outside the scanner. All the subjects were injected with 185–210 megabecquerel of 18F FDG during both stimulations. Statistical parametric mapping version 2 was used in order to assess differences between NC and OC. As a result, we found a significant higher glucose consumption during OC in the cuneus, lingual, and parahippocampal gyri, mainly in the left hemisphere. During NC, our results show a relative higher glucose metabolism in the left superior, inferior, middle, medial frontal, and orbital gyri as well as in the anterior cingulate cortex. The present investigation, performed with a widely available functional imaging clinical tool, may help to better understand the neural responses associated to olfactory processing in healthy individuals and in patients with olfactory disorders by acquiring data in an ecologic, noise-free, and resting condition in which possible cerebral activations related to unwanted attentional processes might be avoided. PMID:25340494

  17. 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

  18. Norepinephrine and Learning-Induced Plasticity in Infant Rat Olfactory System

    PubMed Central

    Sullivan, Regina M.; Wilson, Donald A.; Leon, Michael

    2007-01-01

    Postnatal olfactory learning produces both a conditioned behavioral response and a modified olfactory bulb neural response to the learned odor. The present report describes the role of norepinephrine (NE) on both of these learned responses in neonatal rat pups. Pups received olfactory classical conditioning training from postnatal days (PN) 1-18. Training consisted of 18 trials with an intertrial interval of 24 hr. For the experimental group, a trial consisted of a pairing of unconditioned stimulus (UCS, stroking/tactile stimulation) and the conditioned stimulus (CS, odor). Control groups received either only the CS (Odor only) or only the UCS (Stroke only). Within each training condition, pups were injected with either the NE β-receptor agonist isoproterenol (1, 20, or 4 mg/kg), the NE β-receptor antagonist propranolol (10, 20, 40 mg/kg), or saline 30 min prior to training. On day 20, pups received one of the following tests: (1) behavioral conditioned responding, (2) injection with 14C-2-deoxyglucase (2-DG) and exposed to the CS odor, or (3) tested for olfactory bulb mitral/tufted cell single-unit responses to the CS odor. The results indicated that training with either: (1) Odor-Stroke-Saline, (2) Odor-Stroke-lsoproterenol-Propranolol, or (3) Odor only-lsoproterenol (2 mg/kg) was sufficient to produce a learned behavioral odor preference, enhanced uptake of 14C-2-DG in the odor-specific foci within the bulb, and a modified output signal from the bulb as measured by single-cell recordings of mitral/tufted cells. Moreover, propranolol injected prior to Odor-Stroke training blocked the acquisition of both the learned behavior and olfactory bulb responses. PMID:2585063

  19. Long-term olfactory memories are stabilised via protein synthesis in Camponotus fellah ants.

    PubMed

    Guerrieri, Fernando J; d'Ettorre, Patrizia; Devaud, Jean-Marc; Giurfa, Martin

    2011-10-01

    Ants exhibit impressive olfactory learning abilities. Operant protocols in which ants freely choose between rewarded and non-rewarded odours have been used to characterise associative olfactory learning and memory. Yet, this approach precludes the use of invasive methods allowing the dissection of molecular bases of learning and memory. An open question is whether the memories formed upon olfactory learning that are retrievable several days after training are indeed based on de novo protein synthesis. Here, we addressed this question in the ant Camponotus fellah using a conditioning protocol in which individually harnessed ants learn an association between odour and reward. When the antennae of an ant are stimulated with sucrose solution, the insect extends its maxilla-labium to absorb the solution (maxilla-labium extension response). We differentially conditioned ants to discriminate between two long-chain hydrocarbons, one paired with sucrose and the other with quinine solution. Differential conditioning leads to the formation of a long-term memory retrievable at least 72 h after training. Long-term memory consolidation was impaired by the ingestion of cycloheximide, a protein synthesis blocker, prior to conditioning. Cycloheximide did not impair acquisition of either short-term memory (10 min) or early and late mid-term memories (1 or 12 h). These results show that, upon olfactory learning, ants form different memories with variable molecular bases. While short- and mid-term memories do not require protein synthesis, long-term memories are stabilised via protein synthesis. Our behavioural protocol opens interesting research avenues to explore the cellular and molecular bases of olfactory learning and memory in ants. PMID:21900478

  20. Metabotropic glutamate receptors promote disinhibition of olfactory bulb glomeruli that scales with input strength

    PubMed Central

    Zak, Joseph D.; Whitesell, Jennifer D.

    2014-01-01

    Increasing evidence indicates that the neural circuitry within glomeruli of the olfactory bulb plays a major role in affecting information flow between olfactory sensory neurons (OSNs) and output mitral cells (MCs). Glutamatergic external tufted (ET) cells, located at glomeruli, can act as intermediary cells in excitation between OSNs and MCs, whereas activation of MCs by OSNs is, in turn, suppressed by inhibitory synapses onto ET cells. In this study, we used patch-clamp recordings in rat olfactory bulb slices to examine the function of metabotropic glutamate receptors (mGluRs) in altering these glomerular signaling mechanisms. We found that activation of group II mGluRs profoundly reduced inhibition onto ET cells evoked by OSN stimulation. The mGluRs that mediated disinhibition were located on presynaptic GABAergic periglomerular cells and appeared to be activated by glutamate transients derived from dendrites in glomeruli. In terms of glomerular output, the mGluR-mediated reduction in GABA release led to a robust increase in the number of action potentials evoked by OSN stimulation in both ET cells and MCs. Importantly, however, the enhanced excitation was specific to when a glomerulus was strongly activated by OSN inputs. By being selective for strong vs. weak glomerular activation, mGluR-mediated disinhibition provides a mechanism to enhance the contrast in odor signals that activate OSN inputs into a single glomerulus at varying intensities. PMID:25552635

  1. Efficient Olfactory Coding in the Pheromone Receptor Neuron of a Moth

    PubMed Central

    Kostal, Lubomir; Lansky, Petr; Rospars, Jean-Pierre

    2008-01-01

    The concept of coding efficiency holds that sensory neurons are adapted, through both evolutionary and developmental processes, to the statistical characteristics of their natural stimulus. Encouraged by the successful invocation of this principle to predict how neurons encode natural auditory and visual stimuli, we attempted its application to olfactory neurons. The pheromone receptor neuron of the male moth Antheraea polyphemus, for which quantitative properties of both the natural stimulus and the reception processes are available, was selected. We predicted several characteristics that the pheromone plume should possess under the hypothesis that the receptors perform optimally, i.e., transfer as much information on the stimulus per unit time as possible. Our results demonstrate that the statistical characteristics of the predicted stimulus, e.g., the probability distribution function of the stimulus concentration, the spectral density function of the stimulation course, and the intermittency, are in good agreement with those measured experimentally in the field. These results should stimulate further quantitative studies on the evolutionary adaptation of olfactory nervous systems to odorant plumes and on the plume characteristics that are most informative for the ‘sniffer’. Both aspects are relevant to the design of olfactory sensors for odour-tracking robots. PMID:18437217

  2. Interneurons in the human olfactory system in Alzheimer's disease.

    PubMed

    Saiz-Sanchez, Daniel; Flores-Cuadrado, Alicia; Ubeda-Bañon, Isabel; de la Rosa-Prieto, Carlos; Martinez-Marcos, Alino

    2016-02-01

    The principal olfactory structures display Alzheimer's disease (AD) related pathology at early stages of the disease. Consequently, olfactory deficits are among the earliest symptoms. Reliable olfactory tests for accurate clinical diagnosis are rarely made. In addition, neuropathological analysis postmortem of olfactory structures is often not made. Therefore, the relationship between the clinical features and the underlying pathology is poorly defined. Traditionally, research into Alzheimer's disease has focused on the degeneration of cortical temporal projection neurons and cholinergic neurons. Recent evidence has demonstrated the neurodegeneration of interneuron populations in AD. This review provides an updated overview of the pathological involvement of interneuron populations in the human olfactory system in Alzheimer's disease. PMID:26616239

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

    NASA Astrophysics Data System (ADS)

    Kim, Soyoun

    investigate dynamics of cortical feedback on the olfactory bulb. Using optical imaging with voltage sensitive dyes we showed that cortical feedback induced by stimulating one bulb changes odor evoked oscillatory patterning in the other bulb. We have observed that the feedback front cortical regions reduces overall response in the other olfactory bulb indicating that the cortical feedback has an inhibitory effect on the bulbs. Furthermore the changes in the oscillatory power indicate amplification of fast and slow caudal oscillation and reduction of the rostral oscillation, as was predicted from the model.

  4. Olfactory Epithelium Grafts in the Cerebral Cortex: An Immunohistochemical Analysis

    PubMed Central

    Holbrook, Eric H.; DiNardo, Laurence J.; Costanzo, Richard M.

    2009-01-01

    Objective To develop an alternative model for studying the regenerative capacity of olfactory neurons. Study Design An immunohistochemical analysis of mouse olfactory epithelium transplanted to the cerebral cortex. Methods Strips of olfactory epithelium removed from donor mice at postnatal day 5 to day 20 were inserted into the parietal cortex of adult mice. Recipient animals were allowed to survive for 25 to 120 days and then perfused with 4% paraformaldehyde 1 hour after bromodeoxyuridine injection. The brains were processed, and frozen sections were obtained. Sections through transplant tissue were analyzed using immunohistochemistry and compared with normal olfactory epithelium. Results Graft survival approached 85% with mature olfactory neurons detected in 35% of the transplants stained for olfactory marker protein. Transplant epithelium resembled normal olfactory epithelium containing mature olfactory neurons and axon bundles. Conclusions Studies of olfactory neuron regeneration have been limited by the inability to produce cultures with long-term viability. Olfactory epithelial grafts to the cerebral cortex provide an alternative approach to the study of olfactory neuron regeneration. PMID:11801979

  5. Neurobiological correlates of visual and olfactory recognition in sheep.

    PubMed

    Kendrick, K M

    1994-12-01

    ability to selectively recognise the odour signatures of its own lambs within the first few hours of giving birth. Electrophysiological recordings from mitral cells in the olfactory bulb have shown that none of them respond preferentially to lamb odours pre-partum, when the ewes show no interest in lambs, whereas 60% of them do so after ewes have bonded with their lambs. A sub-population of mitral cells also responds differentially to own and alien lamb odours post-partum. Neurochemical studies have shown that lamb odours do not evoke transmitter release within the olfactory bulb pre-partum whereas, post-partum, own lamb odours stimulate release of the intrinsic amino acid transmitters, GABA and glutamate whereas both own and alien lamb odours evoke equivalent increases in the release of the centrifugal pathway transmitters, acetylcholine and nonadrenaline. Overall these experiments provide compelling evidence that the sheep, which is after all a social animal, makes use of sophisticated visual cues from the face and body and of olfactory cues from the body and wool to recognise different individuals. The neural pathways which are involved in both of these recognition processes also show remarkable evidence of plasticity. However, there appears to be a much closer link between recognition and emotional significance demonstrated in the coding strategies employed by the neural circuits involved in individual recognition in the sheep brain compared to that of a primate and, indeed, they seem to be organised more for identifying a small number of different categories of individuals rather than for a large number of individuals per se. It is possible therefore that social evolutionary pressures to specifically identify large numbers of individuals of similar emotional significance has been achieved by weakening the organisational influence of affect on coding strategies of cells in the temporal cortex in favour of a more extensive feature detection system allowing accurate

  6. Olfactory imprinting is triggered by MHC peptide ligands.

    PubMed

    Hinz, Cornelia; Namekawa, Iori; Namekawa, Ri; Behrmann-Godel, Jasminca; Oppelt, Claus; Jaeschke, Aaron; Müller, Anke; Friedrich, Rainer W; Gerlach, Gabriele

    2013-01-01

    Olfactory imprinting on environmental, population- and kin-specific cues is a specific form of life-long memory promoting homing of salmon to their natal rivers and the return of coral reef fish to natal sites. Despite its ecological significance, natural chemicals for olfactory imprinting have not been identified yet. Here, we show that MHC peptides function as chemical signals for olfactory imprinting in zebrafish. We found that MHC peptides consisting of nine amino acids elicit olfactory imprinting and subsequent kin recognition depending on the MHC genotype of the fish. In vivo calcium imaging shows that some olfactory bulb neurons are highly sensitive to MHC peptides with a detection threshold at 1 pM or lower, indicating that MHC peptides are potent olfactory stimuli. Responses to MHC peptides overlapped spatially with responses to kin odour but not food odour, consistent with the hypothesis that MHC peptides are natural signals for olfactory imprinting. PMID:24077566

  7. Reversible Deafferentation of the Adult Zebrafish Olfactory Bulb Affects Glomerular Distribution and Olfactory-Mediated Behavior

    PubMed Central

    Paskin, Taylor R.; Byrd-Jacobs, Christine A.

    2012-01-01

    The olfactory system is a useful model for studying central nervous system recovery from damage due to its neuroplasticity. We recently developed a novel method of deafferentation by repeated exposure of Triton X-100 to the olfactory organ of adult zebrafish. This long-term, reversible method of deafferentation allows both degeneration and regeneration to be observed in the olfactory bulb. The aim of the present study is to examine olfactory bulb innervation, glomerular patterns, and olfactory-mediated behavior with repeated Triton X-100 treatment and the potential for recovery following cessation of treatment. Olfactory bulbs of control, chronic-treated, and recovery animals were examined for the presence or absence of glomeruli that have been identified in the zebrafish glomerular map. Following chronic treatment, the number of glomeruli was dramatically reduced; however, partial innervation remained in the lateral region of the bulb. When animals were given time to recover, complete glomerular distribution returned. A behavioral assay was developed to determine if innervation remaining correlated with behavior of the fish. Chronic-treated fish did not respond to odorants involved with social behavior but continued to react to odorants that mediate feeding behavior. Following recovery, responses to odorants involved with social behavior returned. The morphological and behavioral effects of chronic Triton X-100 treatment in the olfactory system suggest there may be differential susceptibility or resistance to external damage in a subset of sensory neurons. The results of this study demonstrate the remarkable regenerative ability of the olfactory system following extensive and long-term injury. PMID:22963994

  8. Reversible deafferentation of the adult zebrafish olfactory bulb affects glomerular distribution and olfactory-mediated behavior.

    PubMed

    Paskin, Taylor R; Byrd-Jacobs, Christine A

    2012-12-01

    The olfactory system is a useful model for studying central nervous system recovery from damage due to its neuroplasticity. We recently developed a novel method of deafferentation by repeated exposure of Triton X-100 to the olfactory organ of adult zebrafish. This long-term, reversible method of deafferentation allows both degeneration and regeneration to be observed in the olfactory bulb. The aim of the present study is to examine olfactory bulb innervation, glomerular patterns, and olfactory-mediated behavior with repeated Triton X-100 treatment and the potential for recovery following cessation of treatment. Olfactory bulbs of control, chronic-treated, and recovery animals were examined for the presence or absence of glomeruli that have been identified in the zebrafish glomerular map. Following chronic treatment, the number of glomeruli was dramatically reduced; however, partial innervation remained in the lateral region of the bulb. When animals were given time to recover, complete glomerular distribution returned. A behavioral assay was developed to determine if innervation remaining correlated with behavior of the fish. Chronic-treated fish did not respond to odorants involved with social behavior but continued to react to odorants that mediate feeding behavior. Following recovery, responses to odorants involved with social behavior returned. The morphological and behavioral effects of chronic Triton X-100 treatment in the olfactory system suggest there may be differential susceptibility or resistance to external damage in a subset of sensory neurons. The results of this study demonstrate the remarkable regenerative ability of the olfactory system following extensive and long-term injury. PMID:22963994

  9. Netrin/DCC signaling guides olfactory sensory axons to their correct location in the olfactory bulb

    PubMed Central

    Lakhina, Vanisha; Marcaccio, Christina L.; Shao, Xin; Lush, Mark E.; Jain, Roshan A.; Fujimoto, Esther; Bonkowsky, Joshua L.; Granato, Michael; Raper, Jonathan A.

    2012-01-01

    Olfactory sensory neurons expressing particular olfactory receptors project to specific reproducible locations within the bulb. The axonal guidance cues that organize this precise projection pattern are only beginning to be identified. To aid in their identification and characterization, we generated a transgenic zebrafish line, OR111-7:IRES:Gal4, in which a small subset of olfactory sensory neurons is labeled. Most sensory neurons expressing the OR111-7 transgene project to a specific location within the bulb, the central zone protoglomerulus, while a smaller number project to the LG1 protoglomerulus. Inhibiting netrin/DCC signaling perturbs the ability of OR111-7 expressing axons to enter the olfactory bulb and alters their patterns of termination within the bulb. The netrin receptor DCC is expressed in olfactory sensory neurons around the time that they elaborate their axons, netrin1a is expressed near the medial-most margin of the olfactory bulb, and netrin1b is expressed within the ventral region of the bulb. Loss of netrin/DCC signaling components causes some OR111-7 expressing sensory axons to wander posteriorly after exiting the olfactory pit, away from netrin expressing areas in the bulb. OR111-7 expressing axons that enter the bulb target the central zone less precisely than normal, spreading away from netrin expressing regions. These pathfinding errors can be corrected by the re-expression of DCC within OR111-7 transgene expressing neurons in DCC morphant embryos. These findings implicate netrins as the only known attractants for olfactory sensory neurons, first drawing OR111-7 expressing axons into the bulb and then into the ventromedially positioned central zone protoglomerulus. PMID:22457493

  10. Perception of Odors Linked to Precise Timing in the Olfactory System

    PubMed Central

    Rebello, Michelle R.; McTavish, Thomas S.; Willhite, David C.; Short, Shaina M.; Shepherd, Gordon M.; Verhagen, Justus V.

    2014-01-01

    While the timing of neuronal activity in the olfactory bulb (OB) relative to sniffing has been the object of many studies, the behavioral relevance of timing information generated by patterned activation within the bulbar response has not been explored. Here we show, using sniff-triggered, dynamic, 2-D, optogenetic stimulation of mitral/tufted cells, that virtual odors that differ by as little as 13 ms are distinguishable by mice. Further, mice are capable of discriminating a virtual odor movie based on an optically imaged OB odor response versus the same virtual odor devoid of temporal dynamics—independently of the sniff-phase. Together with studies showing the behavioral relevance of graded glomerular responses and the response timing relative to odor sampling, these results imply that the mammalian olfactory system is capable of very high transient information transmission rates. PMID:25514030

  11. Differential Octopaminergic Modulation of Olfactory Receptor Neuron Responses to Sex Pheromones in Heliothis virescens.

    PubMed

    Hillier, N Kirk; Kavanagh, Rhys M B

    2015-01-01

    Octopamine is an important neuromodulator of neural function in invertebrates. Octopamine increases male moth sensitivity to female sex pheromones, however, relatively little is known as to the role of octopamine in the female olfactory system, nor its possible effects on the reception of non-pheromone odorants. The purpose of this study was to determine relative effects of octopamine on the sensitivity of the peripheral olfactory system in male and female Heliothis virescens. Single sensillum recording was conducted in both sexes following injection with octopamine or Ringer solution, and during odorant stimulation with conspecific female sex pheromone or host plant volatiles. Results indicate that octopamine plays a significant modulatory role in female sex pheromone detection in female moths; and that male and female pheromone detection neurons share distinct pharmacological and physiological similarities in H. virescens despite sexual dimorphism at the antennal level. PMID:26650832

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

    PubMed

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

    2016-02-01

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

  13. Faecal bile acids are natural ligands of the mouse accessory olfactory system.

    PubMed

    Doyle, Wayne I; Dinser, Jordan A; Cansler, Hillary L; Zhang, Xingjian; Dinh, Daniel D; Browder, Natasha S; Riddington, Ian M; Meeks, Julian P

    2016-01-01

    The accessory olfactory system (AOS) guides behaviours that are important for survival and reproduction, but understanding of AOS function is limited by a lack of identified natural ligands. Here we report that mouse faeces are a robust source of AOS chemosignals and identify bile acids as a class of natural AOS ligands. Single-unit electrophysiological recordings from accessory olfactory bulb neurons in ex vivo preparations show that AOS neurons are strongly and selectively activated by peripheral stimulation with mouse faecal extracts. Faecal extracts contain several unconjugated bile acids that cause concentration-dependent neuronal activity in the AOS. Many AOS neurons respond selectively to bile acids that are variably excreted in male and female mouse faeces, and others respond to bile acids absent in mouse faeces. These results identify faeces as a natural source of AOS information, and suggest that bile acids may be mammalian pheromones and kairomones. PMID:27324439

  14. 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.

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

    PubMed Central

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

    2015-01-01

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

  16. Faecal bile acids are natural ligands of the mouse accessory olfactory system

    PubMed Central

    Doyle, Wayne I.; Dinser, Jordan A.; Cansler, Hillary L.; Zhang, Xingjian; Dinh, Daniel D.; Browder, Natasha S.; Riddington, Ian M.; Meeks, Julian P.

    2016-01-01

    The accessory olfactory system (AOS) guides behaviours that are important for survival and reproduction, but understanding of AOS function is limited by a lack of identified natural ligands. Here we report that mouse faeces are a robust source of AOS chemosignals and identify bile acids as a class of natural AOS ligands. Single-unit electrophysiological recordings from accessory olfactory bulb neurons in ex vivo preparations show that AOS neurons are strongly and selectively activated by peripheral stimulation with mouse faecal extracts. Faecal extracts contain several unconjugated bile acids that cause concentration-dependent neuronal activity in the AOS. Many AOS neurons respond selectively to bile acids that are variably excreted in male and female mouse faeces, and others respond to bile acids absent in mouse faeces. These results identify faeces as a natural source of AOS information, and suggest that bile acids may be mammalian pheromones and kairomones. PMID:27324439

  17. Differential Octopaminergic Modulation of Olfactory Receptor Neuron Responses to Sex Pheromones in Heliothis virescens

    PubMed Central

    Hillier, N. Kirk; Kavanagh, Rhys M. B.

    2015-01-01

    Octopamine is an important neuromodulator of neural function in invertebrates. Octopamine increases male moth sensitivity to female sex pheromones, however, relatively little is known as to the role of octopamine in the female olfactory system, nor its possible effects on the reception of non-pheromone odorants. The purpose of this study was to determine relative effects of octopamine on the sensitivity of the peripheral olfactory system in male and female Heliothis virescens. Single sensillum recording was conducted in both sexes following injection with octopamine or Ringer solution, and during odorant stimulation with conspecific female sex pheromone or host plant volatiles. Results indicate that octopamine plays a significant modulatory role in female sex pheromone detection in female moths; and that male and female pheromone detection neurons share distinct pharmacological and physiological similarities in H. virescens despite sexual dimorphism at the antennal level. PMID:26650832

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

    PubMed

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

    2007-03-01

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

  19. 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.

  20. 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…

  1. Resistance to Interference of Olfactory Perceptual Learning

    ERIC Educational Resources Information Center

    Stevenson, Richard J.; Case, Trevor I.; Tomiczek, Caroline

    2007-01-01

    Olfactory memory is especially persistent. The current study explored whether this applies to a form of perceptual learning, in which experience of an odor mixture results in greater judged similarity between its elements. Experiment 1A contrasted 2 forms of interference procedure, "compound" (mixture AW, followed by presentation of new mixtures…

  2. The Olfactory Factor in Nonverbal Communication.

    ERIC Educational Resources Information Center

    Riley, Jobie E.

    This paper on the subject of smell in communication provides a brief survey of the subject, pulling together a wide variety of disparate ideas across many disciplines. The paper is comprised of a general introductory section and separate sections on the olfactory nonverbal communication of animals and human beings. The uses to which animals put…

  3. 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

  4. Mucus trail tracking in a predatory snail: olfactory processing retooled to serve a novel sensory modality

    PubMed Central

    Patel, Kinjal; Shaheen, Nagma; Witherspoon, Jessica; Robinson, Natallia; Harrington, Melissa A

    2014-01-01

    Introduction The rosy wolfsnail (Euglandina rosea), a predatory land snail, finds prey snails and potential mates by following their mucus trails. Euglandina have evolved unique, mobile lip extensions that detect mucus and aid in following trails. Currently, little is known of the neural substrates of the trail-following behavior. Methods To investigate the neural correlates of trail following we used tract-tracing experiments in which nerves were backfilled with either nickel-lysine or Lucifer yellow, extracellular recording of spiking neurons in snail procerebra using a multielectrode array, and behavioral assays of trail following and movement toward the source of a conditioned odor. Results The tract-tracing experiments demonstrate that in Euglandina, the nerves carrying mucus signals innervate the same region of the central ganglia as the olfactory nerves, while the electrophysiology studies show that mucus stimulation of the sensory epithelium on the lip extensions alters the frequency and pattern of neural activity in the procerebrum in a manner similar to odor stimulation of the olfactory epithelium on the optic tentacles of another land snail species, Cantareus aspersa (previously known as Helix aspersa). While Euglandina learn to follow trails of novel chemicals that they contact with their lip extensions in one to three trials, these snails proved remarkably resistant to associative learning in the olfactory modality. Even after seven to nine pairings of odorant molecules with food, they showed no orientation toward the conditioned odor. This is in marked contrast to Cantareus snails, which reliably oriented toward conditioned odors after two to three trials. Conclusions The apparent inability of Euglandina to learn to associate food with odors and use odor cues to drive behavior suggests that the capability for sophisticated neural processing of nonvolatile mucus cues detected by the lip extensions has evolved at the expense of processing of odorant

  5. Temporal response dynamics of Drosophila olfactory sensory neurons depends on receptor type and response polarity

    PubMed Central

    Getahun, Merid N.; Wicher, Dieter; Hansson, Bill S.; Olsson, Shannon B.

    2012-01-01

    Insect olfactory sensory neurons (OSN) express a diverse array of receptors from different protein families, i.e. ionotropic receptors (IR), gustatory receptors (GR) and odorant receptors (OR). It is well known that insects are exposed to a plethora of odor molecules that vary widely in both space and time under turbulent natural conditions. In addition to divergent ligand specificities, these different receptors might also provide an increased range of temporal dynamics and sensitivities for the olfactory system. To test this, we challenged different Drosophila OSNs with both varying stimulus durations (10–2000 ms), and repeated stimulus pulses of key ligands at various frequencies (1–10 Hz). Our results show that OR-expressing OSNs responded faster and with higher sensitivity to short stimulations as compared to IR- and Gr21a-expressing OSNs. In addition, OR-expressing OSNs could respond to repeated stimulations of excitatory ligands up to 5 Hz, while IR-expressing OSNs required ~5x longer stimulations and/or higher concentrations to respond to similar stimulus durations and frequencies. Nevertheless, IR-expressing OSNs did not exhibit adaptation to longer stimulations, unlike OR- and Gr21a-OSNs. Both OR- and IR-expressing OSNs were also unable to resolve repeated pulses of inhibitory ligands as fast as excitatory ligands. These differences were independent of the peri-receptor environment in which the receptors were expressed and suggest that the receptor expressed by a given OSN affects both its sensitivity and its response to transient, intermittent chemical stimuli. OR-expressing OSNs are better at resolving low dose, intermittent stimuli, while IR-expressing OSNs respond more accurately to long-lasting odor pulses. This diversity increases the capacity of the insect olfactory system to respond to the diverse spatiotemporal signals in the natural environment. PMID:23162431

  6. Distinct modifications of convergent excitatory and inhibitory inputs in developing olfactory circuits.

    PubMed

    Ma, T-F; Chen, P-H; Hu, X-Q; Zhao, X-L; Tian, T; Lu, W

    2014-06-01

    The interaction between excitatory and inhibitory inputs is critical to neuronal signal processing. However, little is known about this fundamental property, largely due to the inability to clearly isolate the respective inputs. Here we took advantage of the characteristic stereotypical architecture of synaptic connections in the main olfactory bulb, which enabled us to entirely separate excitatory and inhibitory inputs. Using paired stimulation of two glomeruli located apart at different intensities, we separately elicited excitatory and inhibitory inputs and mimicked stimulation of competing mitral cells (MCs) with different odorants. We performed dual whole-cell patch recording of evoked excitatory postsynaptic responses (EPSPs) and inhibitory postsynaptic responses (IPSPs) in current-clamp mode from two competitive MCs that are connected to the two stimulated glomeruli in slices of the main olfactory bulb in 2-3-week-old rats. We deliberately held the recorded cells at a relative hyperpolarized potential. This manipulation not only suppressed action potential generation but also excluded the possible contamination of inhibitory components in excitatory inputs. We found that in weakly activated MCs repetitive EPSP-IPSP interactions (5 Hz, 180 times) induced long-term potentiation (LTP) and long-term depression (LTD) in convergent excitatory and inhibitory inputs, respectively. Unexpectedly, these forms of plasticity depend on activity of somatic (mainly non-synaptic) NMDA receptors (NMDARs). In contrast, the same repetitive stimulation induced the LTP of excitatory inputs in strongly activated MCs (MC2) that require activity of synaptic NMDARs. These distinct forms of plasticity in the developing olfactory circuit may represent a novel rule of modification in convergent inputs that leads to decorrelation of inputs and facilitates odor discrimination. PMID:24704517

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

    PubMed

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

    2016-06-01

    The rising cost of orthodox medication has endeared so many to the use of herbs for the management of neurological conditions. Rauwolfia vomitoria (RV) one of such herbs is a rainforest shrub whose parts are used locally in the management of psychiatry and other medical issues. Its usefulness though not in doubt is wrapped with adverse reports as its active constituents depletes brain monoamine and dopamine stores. This motivated this research on the effects of the root bark extract on olfaction and the olfactory bulb of adult Wistar rats. Eighteen adult Wistar rats (220g average) were divided into three groups (n=6); control (placebo), 200mg/kg and 400mg/kg RV root bark extract, respectively. The oral administration lasted for seven days and on day 8, test of olfaction was carried out and the animals immediately anaesthetized with ketamine hydrochloride (i.p.) and perfuse-fixed with 10% neutral buffered formalin. All the brains were processed for histology and immunoreactivity. Results showed loss of body weights and olfaction in the 200mg/kg and 400mg/kg RV groups. There was hypertrophy and atrophy of mitral cells respectively, in the 200mg/kg and 400mg/kg RV groups, while there was hyperplasia of cells in the internal granular and plexiform layers of both groups. There was decreased neuron specific enolase (NSE) and neurofilament (NF) expression in the 200mg/kg RV group, while NF and glial fibrillary acidic protein (GFAP) expression was decreased in the 400mg/kg RV group. However, NSE expression was enhanced in the 400mg/kg group, while GFAP expression was enhanced in the 200mg/kg RV group. These results suggest that these doses of RV affect olfaction and appetite, and stimulate adverse cellular changes in the olfactory bulb. PMID:27208729

  8. Olfactory acuity in theropods: palaeobiological and evolutionary implications

    PubMed Central

    Zelenitsky, Darla K.; Therrien, François; Kobayashi, Yoshitsugu

    2008-01-01

    This research presents the first quantitative evaluation of the olfactory acuity in extinct theropod dinosaurs. Olfactory ratios (i.e. the ratio of the greatest diameter of the olfactory bulb to the greatest diameter of the cerebral hemisphere) are analysed in order to infer the olfactory acuity and behavioural traits in theropods, as well as to identify phylogenetic trends in olfaction within Theropoda. A phylogenetically corrected regression of olfactory ratio to body mass reveals that, relative to predicted values, the olfactory bulbs of (i) tyrannosaurids and dromaeosaurids are significantly larger, (ii) ornithomimosaurs and oviraptorids are significantly smaller, and (iii) ceratosaurians, allosauroids, basal tyrannosauroids, troodontids and basal birds are within the 95% CI. Relative to other theropods, olfactory acuity was high in tyrannosaurids and dromaeosaurids and therefore olfaction would have played an important role in their ecology, possibly for activities in low-light conditions, locating food, or for navigation within large home ranges. Olfactory acuity was the lowest in ornithomimosaurs and oviraptorids, suggesting a reduced reliance on olfaction and perhaps an omnivorous diet in these theropods. Phylogenetic trends in olfaction among theropods reveal that olfactory acuity did not decrease in the ancestry of birds, as troodontids, dromaeosaurids and primitive birds possessed typical or high olfactory acuity. Thus, the sense of smell must have remained important in primitive birds and its presumed decrease associated with the increased importance of sight did not occur until later among more derived birds. PMID:18957367

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

    PubMed

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

    2014-05-01

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

  10. 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. PMID:25376305

  11. 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

  12. Site-specific population dynamics and variable olfactory marker protein expression in the postnatal canine olfactory epithelium

    PubMed Central

    Bock, Patricia; Rohn, Karl; Beineke, Andreas; Baumgärtner, Wolfgang; Wewetzer, Konstantin

    2009-01-01

    The main olfactory epithelium is a pseudostratified columnar epithelium that displays neurogenesis over the course of a lifetime. New olfactory neurons arise basally and are transferred to the middle third of the epithelium during maturation. It is generally believed that this pattern is present throughout the olfactory area. In the present study, we show that the postnatal canine olfactory epithelium is composed of two distinct types of epithelium, designated A and B, which not only differ in olfactory neuron morphology, marker expression and basal cell proliferation but also display a patchy distribution and preferential localization within the nasal cavity. Type A epithelium, abundant in the caudal part of the olfactory area, contains well-differentiated olfactory neurons positive for olfactory marker protein but low numbers of immature neurons and proliferating basal cells, as visualized by TrkB/Human Natural Killer-1 (HNK-1) glyco-epitope and Ki-67 immunostaining, respectively. In contrast, type B epithelium is mainly found in the rostral part and contains smaller and elongated neurons that display increased levels of TrkB/Human Natural Killer-1 (HNK-1) glyco-epitope immunoreactivity and a higher number of Ki-67-positive basal cells but lower and variable levels of olfactory marker protein. The vomeronasal organ displays a uniform distribution of molecular markers and proliferating basal cells. The observation that olfactory marker protein in type A and B epithelium is preferentially localized to the nucleus and cytoplasm, respectively, implies correlation between subcellular localization and olfactory neuron maturation and may indicate distinct functional roles of olfactory marker protein. Whether the site-specific population dynamics in the postnatal canine olfactory epithelium revealed in the present study are modulated by physiological parameters, such as airflow, has to be clarified in future studies. PMID:19788548

  13. Nested expression domains for odorant receptors in zebrafish olfactory epithelium.

    PubMed

    Weth, F; Nadler, W; Korsching, S

    1996-11-12

    The mapping of high-dimensional olfactory stimuli onto the two-dimensional surface of the nasal sensory epithelium constitutes the first step in the neuronal encoding of olfactory input. We have used zebrafish as a model system to analyze the spatial distribution of odorant receptor molecules in the olfactory epithelium by quantitative in situ hybridization. To this end, we have cloned 10 very divergent zebrafish odorant receptor molecules by PCR. Individual genes are expressed in sparse olfactory receptor neurons. Analysis of the position of labeled cells in a simplified coordinate system revealed three concentric, albeit overlapping, expression domains for the four odorant receptors analyzed in detail. Such regionalized expression should result in a corresponding segregation of functional response properties. This might represent the first step of spatial encoding of olfactory input or be essential for the development of the olfactory system. PMID:8917589

  14. 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. PMID:26160059

  15. Sex pheromones and amino acids evoke distinctly different spatial patterns of electrical activity in the goldfish olfactory bulb.

    PubMed

    Hanson, L R; Sorensen, P W; Cohen, Y

    1998-11-30

    Until now, electrophysiological studies of the vertebrate olfactory bulb have tested only 'generalist' cues. These studies suggest that odorants are discriminated by a broadly distributed spatial map. In this study, we tested for the first time in a vertebrate the hypothesis that 'specialist' cues (pheromones) are discriminated by a more restricted component of the olfactory bulb. Our model is the male goldfish, Carassius auratus, for which five sex pheromones with both behavioral and physiological activity have now been identified. Electrical activity (electroencephalography: EEG) was recorded over a 12-point grid from the surface of the olfactory bulb, while fish were exposed to one of ten stimuli including: five sex pheromones, two amino acids, two bile steroids and a control. Evoked activity was evaluated by time series analysis. Power ratios were calculated by dividing the power of the dominant frequency in the power spectrum before stimulation by the power of the dominant frequency during stimulation. Next, the average magnitudes of odorant responses were compared using analysis of variance (ANOVA). The spatial patterning of these responses was also described using cluster analysis, which grouped odorants based on the similarity of their spatial patterns of activity. Although all odorants elicited EEG responses with similar dominant frequencies, odorant-specific differences were evident in the size and distribution of these responses. Sex pheromones and bile steroids elicited relatively small responses that were spatially restricted in distinctive manners, although some overlap was evident. In contrast, amino acids consistently produced large responses at all positions. These results are consistent with the hypothesis that vertebrate pheromones are discriminated by a distinctive subcomponent of the vertebrate olfactory system comprised of a relatively small number of olfactory neurons. PMID:10049233

  16. Regulation of cyclic nucleotide-gated channels and membrane excitability in olfactory receptor cells by carbon monoxide

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

    1. The effect of the putative neural messenger carbon monoxide (CO) and the role of the cGMP second-messenger system for olfactory signal generation was examined in isolated olfactory receptor neurons (ORNs) of the tiger salamander. 2. With the use of whole cell voltage-clamp recordings in combination with a series of ionic and pharmological tests, it is demonstrated that exogenously applied CO is a potent activator (K1/2 = 2.9 microM) of cyclic nucleotide-gated (CNG) channels previously described to mediate odor transduction. 3. Several lines of evidence suggest that CO mediates its effect through stimulation of a soluble guanylyl cyclase (sGC) leading to formation of the second-messenger cGMP. This conclusion is based on the findings that CO responses show an absolute requirement for guanosine 5'-triphosphate (GTP) in the internal solution, that no direct effect of CO on CNG currents in the absence of GTP is detectable, and that a blocker of sGC activation, LY85383 (10 microM), completely inhibits the CO response. 4. The dose-response curve for cGMP at CNG channels is used as a calibration to provide a quantitative estimate of the CO-stimulated cGMP formation. This analysis implies that CO is a potent activator of olfactory sGC. 5. Perforated patch recordings using amphotericin B demonstrate that low micromolar doses of CO effectively depolarize the membrane potential of ORNs through tonic activation of CNG channels. This effect in turn regulates excitable and adaptive properties of ORNs and modulates neuronal responsiveness. 6. These data argue for an important role of the cGMP pathway in olfactory signaling and support the idea that CO may function as a diffusible messenger in the olfactory system.

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

    PubMed

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

    2016-07-01

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

  18. 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.

  19. Mirror sniffing: humans mimic olfactory sampling behavior.

    PubMed

    Arzi, Anat; Shedlesky, Limor; Secundo, Lavi; Sobel, Noam

    2014-05-01

    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

  20. 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

  1. Olfactory Orientation and Navigation in Humans.

    PubMed

    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

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

    PubMed

    Oliveira-Pinto, Ana V; Santos, Raquel M; Coutinho, Renan A; Oliveira, Lays M; Santos, Gláucia B; Alho, Ana T L; Leite, Renata E P; Farfel, José M; Suemoto, Claudia K; Grinberg, Lea T; Pasqualucci, Carlos A; Jacob-Filho, Wilson; Lent, Roberto

    2014-01-01

    Sex differences in the human olfactory function reportedly exist for olfactory sensitivity, odorant identification and memory, and tasks in which odors are rated based on psychological features such as familiarity, intensity, pleasantness, and others. Which might be the neural bases for these behavioral differences? The number of cells in olfactory regions, and especially the number of neurons, may represent a more accurate indicator of the neural machinery than volume or weight, but besides gross volume measures of the human olfactory bulb, no systematic study of sex differences in the absolute number of cells has yet been undertaken. In this work, we investigate a possible sexual dimorphism in the olfactory bulb, by quantifying postmortem material from 7 men and 11 women (ages 55-94 years) with the isotropic fractionator, an unbiased and accurate method to estimate absolute cell numbers in brain regions. Female bulbs weighed 0.132 g in average, while male bulbs weighed 0.137 g, a non-significant difference; however, the total number of cells was 16.2 million in females, and 9.2 million in males, a significant difference of 43.2%. The number of neurons in females reached 6.9 million, being no more than 3.5 million in males, a difference of 49.3%. The number of non-neuronal cells also proved higher in women than in men: 9.3 million and 5.7 million, respectively, a significant difference of 38.7%. The same differences remained when corrected for mass. Results demonstrate a sex-related difference in the absolute number of total, neuronal and non-neuronal cells, favoring women by 40-50%. It is conceivable that these differences in quantitative cellularity may have functional impact, albeit difficult to infer how exactly this would be, without knowing the specific circuits cells make. However, the reported advantage of women as compared to men may stimulate future work on sex dimorphism of synaptic microcircuitry in the olfactory bulb. PMID:25372872

  3. Sexual Dimorphism in the Human Olfactory Bulb: Females Have More Neurons and Glial Cells than Males

    PubMed Central

    Oliveira-Pinto, Ana V.; Santos, Raquel M.; Coutinho, Renan A.; Oliveira, Lays M.; Santos, Gláucia B.; Alho, Ana T. L.; Leite, Renata E. P.; Farfel, José M.; Suemoto, Claudia K.; Grinberg, Lea T.; Pasqualucci, Carlos A.; Jacob-Filho, Wilson; Lent, Roberto

    2014-01-01

    Sex differences in the human olfactory function reportedly exist for olfactory sensitivity, odorant identification and memory, and tasks in which odors are rated based on psychological features such as familiarity, intensity, pleasantness, and others. Which might be the neural bases for these behavioral differences? The number of cells in olfactory regions, and especially the number of neurons, may represent a more accurate indicator of the neural machinery than volume or weight, but besides gross volume measures of the human olfactory bulb, no systematic study of sex differences in the absolute number of cells has yet been undertaken. In this work, we investigate a possible sexual dimorphism in the olfactory bulb, by quantifying postmortem material from 7 men and 11 women (ages 55–94 years) with the isotropic fractionator, an unbiased and accurate method to estimate absolute cell numbers in brain regions. Female bulbs weighed 0.132 g in average, while male bulbs weighed 0.137 g, a non-significant difference; however, the total number of cells was 16.2 million in females, and 9.2 million in males, a significant difference of 43.2%. The number of neurons in females reached 6.9 million, being no more than 3.5 million in males, a difference of 49.3%. The number of non-neuronal cells also proved higher in women than in men: 9.3 million and 5.7 million, respectively, a significant difference of 38.7%. The same differences remained when corrected for mass. Results demonstrate a sex-related difference in the absolute number of total, neuronal and non-neuronal cells, favoring women by 40–50%. It is conceivable that these differences in quantitative cellularity may have functional impact, albeit difficult to infer how exactly this would be, without knowing the specific circuits cells make. However, the reported advantage of women as compared to men may stimulate future work on sex dimorphism of synaptic microcircuitry in the olfactory bulb. PMID:25372872

  4. Neuronal chloride accumulation in olfactory epithelium of mice lacking NKCC1

    PubMed Central

    Nickell, William T.; Kleene, Nancy K.; Gesteland, Robert C.; Kleene, Steven J.

    2005-01-01

    When stimulated with odorants, olfactory receptor neurons (ORNs) produce a depolarizing receptor current. In isolated ORNs, much of this current is due to an efflux of Cl−. This implies that the neurons have one or more mechanisms for accumulating cytoplasmic Cl− at rest. Whether odors activate an efflux of Cl− in intact olfactory epithelium, where the ionic environment is poorly characterized, has not been previously determined. In mouse olfactory epithelium, we find that >80% of the summated electrical response to odors is blocked by niflumic acid or flufenamic acid, each of which inhibits Ca2+-activated Cl− channels in ORNs. This indicates that ORNs accumulate Cl− in situ. Recent evidence has shown that NKCC1, a Na+-K+-2Cl− cotransporter, contributes to Cl− accumulation in mammalian ORNs. However, we find that the epithelial response to odors is only reduced by 39% in mice carrying a null mutation in Nkcc1. As in the wild type, most of the response is blocked by niflumic acid or flufenamic acid, indicating that the underlying current is carried by Cl−. We conclude that ORNs effectively accumulate Cl− in situ even in the absence of NKCC1. The Cl−-transport mechanism underlying this accumulation has not yet been identified. PMID:16319203

  5. Spatial olfactory learning facilitates long-term depression in the hippocampus.

    PubMed

    André, Marion Agnès Emma; Manahan-Vaughan, Denise

    2013-10-01

    Recently, it has emerged that visual spatial exploration facilitates synaptic plasticity at different synapses within the trisynaptic network. Particularly striking is the finding that visuospatial contexts facilitate hippocampal long-term depression (LTD), raising the possibility that this form of plasticity may be important for memory formation. It is not known whether other sensory modalities elicit similar permissive effects on LTD. Here, we explored if spatial olfactory learning facilitates LTD in the hippocampus region of freely behaving rats. Patterned afferent stimulation of the Schaffer collaterals elicited short-term depression (STD) (<1 h) of evoked responses in the Stratum radiatum of the CA1 region. Coupling of this protocol with novel exploration of a spatial constellation of olfactory cues facilitated short-term depression into LTD that lasted for over 24 h. Facilitation of LTD did not occur when animals were re-exposed 1 week later to the same odors in the same spatial constellation. Evaluation of learning behavior revealed that 1 week after the 1st odor exposure, the animals remembered the odors and their relative positions. These data support that the hippocampus can use nonvisuospatial resources, and specifically can use spatial olfactory information, to facilitate LTD and to generate spatial representations. The data also support that a tight relationship exists between the processing of spatial contextual information and the expression of LTD in the hippocampus. PMID:23804412

  6. Profound Olfactory Dysfunction in Myasthenia Gravis

    PubMed Central

    Leon-Sarmiento, Fidias E.; Bayona, Edgardo A.; Bayona-Prieto, Jaime; Osman, Allen; Doty, Richard L.

    2012-01-01

    In this study we demonstrate that myasthenia gravis, an autoimmune disease strongly identified with deficient acetylcholine receptor transmission at the post-synaptic neuromuscular junction, is accompanied by a profound loss of olfactory function. Twenty-seven MG patients, 27 matched healthy controls, and 11 patients with polymiositis, a disease with peripheral neuromuscular symptoms analogous to myasthenia gravis with no known central nervous system involvement, were tested. All were administered the University of Pennsylvania Smell Identification Test (UPSIT) and the Picture Identification Test (PIT), a test analogous in content and form to the UPSIT designed to control for non-olfactory cognitive confounds. The UPSIT scores of the myasthenia gravis patients were markedly lower than those of the age- and sex-matched normal controls [respective means (SDs) = 20.15 (6.40) & 35.67 (4.95); p<0.0001], as well as those of the polymiositis patients who scored slightly below the normal range [33.30 (1.42); p<0.0001]. The latter finding, along with direct monitoring of the inhalation of the patients during testing, implies that the MG-related olfactory deficit is unlikely due to difficulties sniffing, per se. All PIT scores were within or near the normal range, although subtle deficits were apparent in both the MG and PM patients, conceivably reflecting influences of mild cognitive impairment. No relationships between performance on the UPSIT and thymectomy, time since diagnosis, type of treatment regimen, or the presence or absence of serum anti-nicotinic or muscarinic antibodies were apparent. Our findings suggest that MG influences olfactory function to the same degree as observed in a number of neurodegenerative diseases in which central nervous system cholinergic dysfunction has been documented. PMID:23082113

  7. Electrophysiological Measurements from a Moth Olfactory System

    PubMed Central

    Syed, Zainulabeuddin; Leal, Walter S.

    2011-01-01

    Insect olfactory systems provide unique opportunities for recording odorant-induced responses in the forms of electroantennograms (EAG) and single sensillum recordings (SSR), which are summed responses from all odorant receptor neurons (ORNs) located on the antenna and from those housed in individual sensilla, respectively. These approaches have been exploited for getting a better understanding of insect chemical communication. The identified stimuli can then be used as either attractants or repellents in management strategies for insect pests. PMID:21490575

  8. 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

  9. 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. PMID:25071468

  10. 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

  11. 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

  12. Functional neuroanatomy of Drosophila olfactory memory formation.

    PubMed

    Guven-Ozkan, Tugba; Davis, Ronald L

    2014-10-01

    New approaches, techniques and tools invented over the last decade and a half have revolutionized the functional dissection of neural circuitry underlying Drosophila learning. The new methodologies have been used aggressively by researchers attempting to answer three critical questions about olfactory memories formed with appetitive and aversive reinforcers: (1) Which neurons within the olfactory nervous system mediate the acquisition of memory? (2) What is the complete neural circuitry extending from the site(s) of acquisition to the site(s) controlling memory expression? (3) How is information processed across this circuit to consolidate early-forming, disruptable memories to stable, late memories? Much progress has been made and a few strong conclusions have emerged: (1) Acquisition occurs at multiple sites within the olfactory nervous system but is mediated predominantly by the γ mushroom body neurons. (2) The expression of long-term memory is completely dependent on the synaptic output of α/β mushroom body neurons. (3) Consolidation occurs, in part, through circuit interactions between mushroom body and dorsal paired medial neurons. Despite this progress, a complete and unified model that details the pathway from acquisition to memory expression remains elusive. PMID:25225297

  13. Olfactory conditioning in the zebrafish (Danio rerio).

    PubMed

    Braubach, Oliver R; Wood, Heather-Dawn; Gadbois, Simon; Fine, Alan; Croll, Roger P

    2009-03-01

    The zebrafish olfactory system is an attractive model for studying neural processing of chemosensory information. Here we characterize zebrafish olfactory behaviors and their modification through learning, using an apparatus consisting of a circular flow-through tank that allows controlled administration of odorants. When exposed to the amino acids l-alanine and l-valine, naive zebrafish responded with appetitive swimming behavior, which we measured as the number of >90 degrees turns made during 30s observation periods. Such appetitive responses were not observed when naive zebrafish were exposed to an unnatural odorant, phenylethyl alcohol (PEA). Repeated pairing of amino acids or PEA (conditioned stimuli, CS) with food flakes (unconditioned stimuli; UCS) increased odorant-evoked appetitive swimming behavior in all fish tested. The zebrafish also learned to restrict this behavior to the vicinity of a feeding ring, through which UCS were administered. When both nares were temporarily occluded, conditioned fish failed to respond to odorants, confirming that these behaviors were mediated by olfaction. These results represent the first demonstration of a classically conditioned appetitive response to a behaviorally neutral odorant in fish. Furthermore, they complement recent demonstrations of conditional place preferences in fish. By virtue of its robustness and simplicity, this method will be a useful tool for future research into the biological basis of olfactory learning in zebrafish. PMID:19056431

  14. Neurally Encoding Time for Olfactory Navigation.

    PubMed

    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

  15. Circadian regulation of insect olfactory learning.

    PubMed

    Decker, Susan; McConnaughey, Shannon; Page, Terry L

    2007-10-01

    Olfactory learning in insects has been used extensively for studies on the neurobiology, genetics, and molecular biology of learning and memory. We show here that the ability of the cockroach Leucophaea maderae to acquire olfactory memories is regulated by the circadian system. We investigated the effect of training and testing at different circadian phases on performance in an odor-discrimination test administered 30 min after training (short-term memory) or 48 h after training (long-term memory). When odor preference was tested by allowing animals to choose between two odors (peppermint and vanilla), untrained cockroaches showed a clear preference for vanilla at all circadian phases, indicating that there was no circadian modulation of initial odor preference or ability to discriminate between odors. After differential conditioning, in which peppermint odor was associated with a positive unconditioned stimulus of sucrose solution and vanilla odor was associated with a negative unconditioned stimulus of saline solution, cockroaches conditioned in the early subjective night showed a strong preference for peppermint and retained the memory for at least 2 days. Animals trained and tested at other circadian phases showed significant deficits in performance for both short- and long-term memory. Performance depended on the circadian time (CT) of training, not the CT of testing, and results indicate that memory acquisition rather than retention or recall is modulated by the circadian system. The data suggest that the circadian system can have profound effects on olfactory learning in insects. PMID:17893338

  16. Olfactory deprivation increases dopamine D2 receptor density in the rat olfactory bulb

    SciTech Connect

    Guthrie, K.M.; Pullara, J.M.; Marshall, J.F.; Leon, M. )

    1991-05-01

    Unilateral olfactory deprivation during postnatal development results in significant anatomical and neurochemical changes in the deprived olfactory bulb. Perhaps the most dramatic neurochemical change is the loss of dopaminergic expression by neurons of the glomerular region. The authors describe here the effects of early olfactory deprivation on other elements of the bulb dopaminergic system, namely the dopamine receptors of the olfactory bulb. Rat pups had a single naris occluded on postnatal day 2 (PN2). On PN20 or PN60, animals were sacrificed and the bulbs were examined for catecholamine levels or D2 and D1 dopamine receptor binding. Receptor densities were quantified by in vitro autoradiography using the tritiated antagonists spiperone (D2) and SCH23390 (D1). Dopamine uptake sites were similarly examined using tritiated mazindol. No significant specific labeling of D1 or mazindol sites was observed in the olfactory bulbs of control or experimental animals at either age. Normal animals displayed prominent labeling of D2 sites in the glomerular and nerve layers. After 60 days of deprivation, deprived bulbs exhibited an average increase in D2 receptor density of 32%. As determined by Scatchard analysis, the mean values for Kd and Bmax were 0.134 nM and 293 fmol/mg protein in normal bulbs, and 0.136 nM and 403 fmol/mg protein in deprived bulbs. The results suggest that, as in the neostriatum, dopamine depletion in the olfactory bulb leads to an upregulation of D2 receptor sites. This change may represent an attempt by the system to adapt neurochemically to reduced dopaminergic activity and thereby maintain bulb function.

  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. PMID:25711735

  18. The Generation of Olfactory Epithelial Neurospheres in vitro Predicts Engraftment Capacity following Transplantation in vivo

    PubMed Central

    Krolewski, Richard C.; Jang, Woochan; Schwob, James E.

    2011-01-01

    The stem and progenitor cells of the olfactory epithelium maintain the tissue throughout life and effectuate epithelial reconstitution after injury. We have utilized free-floating olfactory neurosphere cultures to study factors influencing proliferation, differentiation, and transplantation potency of sphere-grown cells as a first step toward using them for therapeutic purposes. Olfactory neurospheres form best and expand most when grown from neonatal epithelium, although methyl bromide-injured or normal adult material is weakly spherogenic. The spheres contain the full range of epithelial cell types as marked by cytokeratins, neuron-specific antigens, E-cadherin, Sox2, and Sox9. Globose basal cells are also prominent constituents. Media conditioned by growth of phorbol ester-stimulated, immortalized lamina propria-derived cells (LPImm) significantly increases the percentage of Neurog1eGFP (+) progenitors and immature neurons in spheres. Sphere-forming capacity resides within selected populations; FACS-purified, Neurog1eGFP (+) cells were poorly spherogenic, while preparations from ΔSox2eGFP transgenic mice that are enriched for Sox2(+) basal cells formed spheres very efficiently. Finally, we compared the potency following transplantation of cells grown in spheres vs. cells derived from adherent cultures. The sphere-derived cells engrafted and produced colonies with multiple cell types that incorporated into and resembled host epithelium; cells from adherent cultures did not. Furthermore, cells from spheres grown in conditioned media from the phorbol ester-activated LPImm line gave rise to significantly more neurons after transplantation as compared with control. The current findings demonstrate that sphere formation serves as a biomarker for engraftment capacity and multipotency of olfactory progenitors, which are requirements for their eventual translational use. PMID:21376038

  19. Modification of Male Courtship Motivation by Olfactory Habituation via the GABAA Receptor in Drosophila melanogaster

    PubMed Central

    Tachibana, Shin-Ichiro; Touhara, Kazushige; Ejima, Aki

    2015-01-01

    A male-specific component, 11-cis-vaccenyl acetate (cVA) works as an anti-aphrodisiac pheromone in Drosophila melanogaster. The presence of cVA on a male suppresses the courtship motivation of other males and contributes to suppression of male-male homosexual courtship, while the absence of cVA on a female stimulates the sexual motivation of nearby males and enhances the male-female interaction. However, little is known how a male distinguishes the presence or absence of cVA on a target fly from either self-produced cVA or secondhand cVA from other males in the vicinity. In this study, we demonstrate that male flies have keen sensitivity to cVA; therefore, the presence of another male in the area reduces courtship toward a female. This reduced level of sexual motivation, however, could be overcome by pretest odor exposure via olfactory habituation to cVA. Real-time imaging of cVA-responsive sensory neurons using the neural activity sensor revealed that prolonged exposure to cVA decreased the levels of cVA responses in the primary olfactory center. Pharmacological and genetic screening revealed that signal transduction via GABAA receptors contributed to this olfactory habituation. We also found that the habituation experience increased the copulation success of wild-type males in a group. In contrast, transgenic males, in which GABA input in a small subset of local neurons was blocked by RNAi, failed to acquire the sexual advantage conferred by habituation. Thus, we illustrate a novel phenomenon in which olfactory habituation positively affects sexual capability in a competitive environment. PMID:26252206

  20. 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.

  1. Olfactory signals and the MHC: a review and a case study in Lemur catta.

    PubMed

    Knapp, Leslie A; Robson, Julie; Waterhouse, John S

    2006-06-01

    The major histocompatibility complex (MHC) is the most polymorphic genetic system known in vertebrates. Decades of research demonstrate that it plays a critical role in immune response and disease resistance. It has also been suggested that MHC genes influence social behavior and reproductive phenomena. Studies in laboratory mice and rats report that kin recognition and mate choice are influenced by olfactory cues determined at least in part by an individual's MHC genes. This issue has stimulated intense but controversial research. However, work in this field has only been carried out in rodents and humans. Thus far, no study has directly investigated the relationship between olfactory cues and MHC genotype in nonhuman primates. Furthermore, other genetic loci, including those linked to the MHC, have not been ruled out as the primary influence on odor profiles. To explore the relationship between individual odor profiles and MHC alleles, we are studying ring-tailed lemurs (Lemur catta). These animals are an ideal model species because they are extremely scent-oriented and their behaviors suggest that olfactory signals form an important part of their intra- and intergroup communication systems. Individual odor profiles from tail and scent gland samples were generated for six males using gas chromatography mass spectrometry (GC-MS). MHC genotypes were identified using polymerase chain reaction (PCR) and denaturing gradient gel electrophoresis (DGGE). The GC-MS analyses demonstrated a difference between profiles obtained from tail and scent gland samples. Although our sample size is relatively small and statistical significance could not be obtained, our analyses suggest a relationship between MHC and concentrations of volatile compounds. While these results are preliminary, they support the need for further studies of the MHC and olfactory signals in lemurs and other primates. PMID:16715507

  2. Novel Behavioral Paradigm Reveals Lower Temporal Limits on Mouse Olfactory Decisions

    PubMed Central

    Resulaj, Arbora

    2015-01-01

    Temporal limits on perceptual decisions set strict boundaries on the possible underlying neural computations. How odor information is encoded in the olfactory system is still poorly understood. Here, we sought to define the limit on the speed of olfactory processing. To achieve this, we trained mice to discriminate different odor concentrations in a novel behavioral setup with precise odor delivery synchronized to the sniffing cycle. Mice reported their choice by moving a horizontal treadmill with their front limbs. We found that mice reported discriminations of 75% accuracy in 70–90 ms after odor inhalation. For a low concentration and nontrigeminal odorant, this time was 90–140 ms, showing that mice process odor information rapidly even in the absence of trigeminal stimulation. These response times establish, after accounting for odor transduction and motor delays, that olfactory processing can take tens of milliseconds. This study puts a strong limit on the underlying neural computations and suggests that the action potentials forming the neural basis for these decisions are fired in a few tens of milliseconds. SIGNIFICANCE STATEMENT Understanding how sensory information is processed requires different approaches that span multiple levels of investigation from genes to neurons to behavior. Limits on behavioral performance constrain the possible neural mechanisms responsible for specific computations. Using a novel behavioral paradigm, we established that mice can make decisions about odor intensity surprisingly fast. After accounting for sensory and motor delays, the limit on some olfactory neural computations can be as low as a few tens of milliseconds, which suggests that only the first action potentials across a population of neurons contribute to these computations. PMID:26290243

  3. Photoperiod Mediated Changes in Olfactory Bulb Neurogenesis and Olfactory Behavior in Male White-Footed Mice (Peromyscus leucopus)

    PubMed Central

    Weil, Zachary M.; Nelson, Randy J.

    2012-01-01

    Brain plasticity, in relation to new adult mammalian neurons generated in the subgranular zone of the hippocampus, has been well described. However, the functional outcome of new adult olfactory neurons born in the subventricular zone of the lateral ventricles is not clearly defined, as manipulating neurogenesis through various methods has given inconsistent and conflicting results in lab mice. Several small rodent species, including Peromyscus leucopus, display seasonal (photoperiodic) brain plasticity in brain volume, hippocampal function, and hippocampus-dependent behaviors; plasticity in the olfactory system of photoperiodic rodents remains largely uninvestigated. We exposed adult male P. leucopus to long day lengths (LD) and short day lengths (SD) for 10 to 15 weeks and then examined olfactory bulb cell proliferation and survival using the thymidine analog BrdU, olfactory bulb granule cell morphology using Golgi-Cox staining, and behavioral investigation of same-sex conspecific urine. SD mice did not differ from LD counterparts in granular cell morphology of the dendrites or in dendritic spine density. Although there were no differences due to photoperiod in habituation to water odor, SD mice rapidly habituated to male urine, whereas LD mice did not. In addition, short day induced changes in olfactory behavior were associated with increased neurogenesis in the caudal plexiform and granule cell layers of the olfactory bulb, an area known to preferentially respond to water-soluble odorants. Taken together, these data demonstrate that photoperiod, without altering olfactory bulb neuronal morphology, alters olfactory bulb neurogenesis and olfactory behavior in Peromyscus leucopus. PMID:22912730

  4. Morphometry of olfactory lamellae and olfactory receptor neurons during the life history of chum salmon (Oncorhynchus keta).

    PubMed

    Kudo, Hideaki; Shinto, Masakazu; Sakurai, Yasunori; Kaeriyama, Masahide

    2009-09-01

    It is generally accepted that anadromous Pacific salmon (genus Oncorhynchus) imprint to odorants in their natal streams during their seaward migration and use olfaction to identify these during their homeward migration. Despite the importance of the olfactory organ during olfactory imprinting, the development of this structure is not well understood in Pacific salmon. Olfactory cues from the environment are relayed to the brain by the olfactory receptor neurons (ORNs) in the olfactory organ. Thus, we analyzed morphometric changes in olfactory lamellae of the peripheral olfactory organ and in the quantity of ORNs during life history from alevin to mature in chum salmon (Oncorhynchus keta). The number of lamellae increased markedly during early development, reached 18 lamellae per unilateral peripheral olfactory organ in young salmon with a 200 mm in body size, and maintained this lamellar complement after young period. The number of ORNs per olfactory organ was about 180,000 and 14.2 million cells in fry and mature salmon, respectively. The relationship between the body size (fork length) and number of ORNs therefore revealed an allometric association. Our results represent the first quantitative analysis of the number of ORNs in Pacific salmon and suggest that the number of ORNs is synchronized with the fork length throughout its life history. PMID:19587025

  5. Mechanisms underlying odorant-induced and spontaneous calcium signals in olfactory receptor neurons of spiny lobsters, Panulirus argus.

    PubMed

    Tadesse, Tizeta; Derby, Charles D; Schmidt, Manfred

    2014-01-01

    We determined if a newly developed antennule slice preparation allows studying chemosensory properties of spiny lobster olfactory receptor neurons under in situ conditions with Ca(2+) imaging. We show that chemical stimuli reach the dendrites of olfactory receptor neurons but not their somata, and that odorant-induced Ca(2+) signals in the somata are sufficiently stable over time to allow stimulation with a substantial number of odorants. Pharmacological manipulations served to elucidate the source of odorant-induced Ca(2+) transients and spontaneous Ca(2+) oscillations in the somata of olfactory receptor neurons. Both Ca(2+) signals are primarily mediated by an influx of extracellular Ca(2+) through voltage-activated Ca(2+) channels that can be blocked by CoCl2 and the L-type Ca(2+) channel blocker verapamil. Intracellular Ca(2+) stores contribute little to odorant-induced Ca(2+) transients and spontaneous Ca(2+) oscillations. The odorant-induced Ca(2+) transients as well as the spontaneous Ca(2+) oscillations depend on action potentials mediated by Na(+) channels that are largely TTX-insensitive but blocked by the local anesthetics tetracaine and lidocaine. Collectively, these results corroborate the conclusion that odorant-induced Ca(2+) transients and spontaneous Ca(2+) oscillations in the somata of olfactory receptor neurons closely reflect action potential activity associated with odorant-induced phasic-tonic responses and spontaneous bursting, respectively. Therefore, both types of Ca(2+) signals represent experimentally accessible proxies of spiking. PMID:24178131

  6. Development of the olfactory system in a wallaby (Macropus eugenii).

    PubMed

    Ashwell, K W S; Marotte, L R; Cheng, Gang

    2008-01-01

    We used carbocyanine dye tracing techniques in conjunction with hematoxylin and eosin staining, immunohistochemistry for GAP-43, and tritiated thymidine autoradiography to examine the development of the olfactory pathways in early pouch young tammar wallabies (Macropus eugenii). The overarching aim was to test the hypothesis that the olfactory system of newborn tammars is sufficiently mature at birth to contribute to the guidance of the pouch young to the nipple. Although GAP-43 immunoreactive fibers emerge from the olfactory epithelium and enter the olfactory bulb at birth, all other components of the olfactory pathway in newborn tammars are very immature at birth, postnatal day (P0). In particular, maturation of the vomeronasal organ and its projections to the accessory olfactory bulb appears to be delayed until P5 and the olfactory bulb is poorly differentiated until P12, with glomerular formation delayed until P25. The lateral olfactory tract is also very immature at birth with pioneer axons having penetrated only the most rostral portion of the piriform lobe. Interestingly, there were some early (P0) projections from the olfactory epithelium to the medial septal region and lamina terminalis (by the terminal nerve) and to olfactory tubercle and basal forebrain. The former of these is presumably serving the transfer of LHRH(+) neurons to the forebrain, as seen in eutherians, but neither of these very early pathways is sufficiently robust or connected to the more caudal neuraxis to play a role in nipple finding. Tritiated thymidine autoradiography confirmed that most piriform cortex pyramidal neurons are generated in the first week of life and are unlikely to be able to contribute to circuitry guiding the climb to the pouch. Our findings lead us to reject the hypothesis that olfactory projections contribute to guidance of the newborn tammar to the pouch and nipple. It appears far more likely that the trigeminal pathways play a significant role in this behavior

  7. Immunohistochemical demonstration of salmon olfactory glutathione S-transferase class pi (N24) in the olfactory system of lacustrine sockeye salmon during ontogenesis and cell proliferation.

    PubMed

    Yanagi, S; Kudo, H; Doi, Y; Yamauchi, K; Ueda, H

    2004-06-01

    In mammals, glutathione S-transferase (GST) in the olfactory epithelium is involved in assistance of the olfactory reception by the xenobiotic metabolism. We previously reported the protein and gene expressions of salmon olfactory GST class pi (soGST) in the olfactory receptor cells (ORCs) of the salmonid fish. However, the chronological appearances of soGST in ORCs during ontogeny and cell proliferation are still unknown in this species. In this study, we performed immunohistochemistry of soGST using an antibody specific to soGST in the olfactory system (olfactory placode, olfactory pit, olfactory epithelium, olfactory nerve and olfactory bulb) of lacustrine sockeye salmon ( Oncorhynchus nerka) embryos and 5-bromo-2'-deoxyuridine (BrdU) experimental fish. The projection of olfactory nerve bundles from the olfactory pit to the presumptive olfactory bulb was identified at embryonic day 28 after fertilization. The olfactory cilia were first detected on the apical surface of ORCs at day 43. soGST-immunoreactivity was first detected within the olfactory pit cells at day 55. At 58 day, the number of soGST-immunoreactive cells increased markedly in the olfactory epithelia, and soGST-immunoreactive fibers were observed in the olfactory nerves and olfactory bulbs. By in vivo uptake of BrdU in 1-year-old fish, we observed for the first time at day 7 after labeling that the olfactory epithelia showed ORCs in which both soGST-immunoreactivity and BrdU coexisted. These results indicate that soGST is synthesized in the mature ORCs of lacustrine sockeye salmon after cell formation and differentiation. PMID:15156400

  8. 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

  9. Recovery of Olfactory Function in Postviral Olfactory Dysfunction Patients after Acupuncture Treatment

    PubMed Central

    Dai, Qi; Pang, Zhihui; Yu, Hongmeng

    2016-01-01

    Introduction. The aims of this study were to assess the impact of traditional Chinese acupuncture (TCA) in postviral olfactory dysfunction (PVOD) patients who were refractory to standardized treatment and to compare the results with the impact observed in an observation group. Methods. Fifty patients who presented to the outpatient clinic with PVOD and were refractory to standardized treatment were included: 25 were treated with TCA and 25 patients were simply observed. A subjective olfactory test was performed using the University of Pennsylvania Smell Identification Test (UPSIT). The effects of TCA were compared with the results obtained in the observation group. Results. Improved olfactory function was observed in eleven patients treated with TCA compared with four patients in the observation group. This study revealed significantly improved olfactory function outcomes in patients who underwent acupuncture compared with the observation group. No significant differences in olfaction recovery were found according to age, gender, or duration of disease between the two groups; however, hyposmic patients recovered at a higher rate than anosmic patients. Conclusion. TCA may aid the treatment of PVOD patients who are refractory to drugs or other therapies. PMID:27034689

  10. Olfactory lateralization in homing pigeons: a GPS study on birds released with unilateral olfactory inputs.

    PubMed

    Gagliardo, Anna; Filannino, Caterina; Ioalè, Paolo; Pecchia, Tommaso; Wikelski, Martin; Vallortigara, Giorgio

    2011-02-15

    A large body of evidence has shown that pigeons rely on an olfactory-based navigational map when homing from unfamiliar locations. Previous studies on pigeons released with one nostril occluded highlighted an asymmetry in favour of the right nostril, particularly concerning the initial orientation performance of naïve birds. Nevertheless, all pigeons experiencing only unilateral olfactory input showed impaired homing, regardless of the side of the occluded nostril. So far this phenomenon has been documented only by observing the birds' vanishing bearings. In the present work we recorded the flight tracks of pigeons with previous homing experience equipped with a GPS data logger and released from an unfamiliar location with the right or the left nostril occluded. The analysis of the tracks revealed that the flight path of the birds with the right nostril occluded was more tortuous than that of unmanipulated controls. Moreover, the pigeons smelling with the left nostril interrupted their journey significantly more frequently and displayed more exploratory activity than the control birds, e.g. during flights around a stopover site. These data suggest a more important involvement of the right olfactory system in processing the olfactory information needed for the operation of the navigational map. PMID:21270307

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

    PubMed Central

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

    2014-01-01

    Perception of olfactory stimuli is mediated by distinct populations of olfactory sensory neurons, each with a characteristic set of morphological as well as functional parameters. Beyond two large populations of ciliated and microvillous neurons, a third population, crypt neurons, has been identified in teleost and cartilaginous fishes. We report here a novel, fourth olfactory sensory neuron population in zebrafish, which we named kappe neurons for their characteristic shape. Kappe neurons are identified by their Go-like immunoreactivity, and show a distinct spatial distribution within the olfactory epithelium, similar to, but significantly different from that of crypt neurons. Furthermore, kappe neurons project to a single identified target glomerulus within the olfactory bulb, mdg5 of the mediodorsal cluster, whereas crypt neurons are known to project exclusively to the mdg2 glomerulus. Kappe neurons are negative for established markers of ciliated, microvillous and crypt neurons, but appear to have microvilli. Kappe neurons constitute the fourth type of olfactory sensory neurons reported in teleost fishes and their existence suggests that encoding of olfactory stimuli may require a higher complexity than hitherto assumed already in the peripheral olfactory system. PMID:24509431

  12. 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…

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

    NASA Astrophysics Data System (ADS)

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

    2014-02-01

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

  14. 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....

  15. 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....

  16. 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....

  17. Ultrastructural study of the primary olfactory pathway in Macaca fascicularis.

    PubMed

    Herrera, Loren P; Casas, Carlos E; Bates, Margaret L; Guest, James D

    2005-08-01

    Olfactory ensheathing glial cells (OEGs) interact with a wide repertoire of cell types and support extension of olfactory axons (OAs) within the olfactory pathway. OEGs are thought to exclude OAs from contact with all other cells between the olfactory epithelium and the glomerulus of the olfactory bulb. These properties have lead to testing to determine whether OEGs support axonal growth following transplantation. The cellular interactions of transplanted OEGs will probably resemble those that occur within the normal pathway where interactions between OEGs and fibroblasts are prominent. No previous primate studies have focused on these interactions, knowledge of which is important if clinical application is envisioned. We describe the detailed intercellular interactions of OAs with supporting cells throughout the olfactory epithelium, the lamina propria, the fila olfactoria, and the olfactory nerve layer by using transmission electron microscopy in adult Macaca fascicularis. Patterns of OEG ensheathment and variations of the endo- and perineurium formed by olfactory nerve fibroblasts are described. OAs mainly interacted with horizontal basal cells, OEGs, and astrocytes. At both transitional ends of the pathway seamless intercellular interactions were observed, and fibroblast processes were absent. Perineurial cells produced surface basal lamina; however, endoneurial, epineurial, and meningeal fibroblasts did not. Perineurial cells contained intermediate filaments and were distinct from other fibroblasts and meningeal cells. OAs had direct contacts with astrocytes near the glia limitans. The properties of OEGs differed depending on whether astrocytic or fibroblastic processes were present. This indicates the importance of the cellular milieu in the structure and function of OEGs in primates. PMID:15973683

  18. Odor memories regulate olfactory receptor expression in the sensory periphery.

    PubMed

    Claudianos, Charles; Lim, Julianne; Young, Melanie; Yan, Shanzhi; Cristino, Alexandre S; Newcomb, Richard D; Gunasekaran, Nivetha; Reinhard, Judith

    2014-05-01

    Odor learning induces structural and functional modifications throughout the olfactory system, but it is currently unknown whether this plasticity extends to the olfactory receptors (Or) in the sensory periphery. Here, we demonstrate that odor learning induces plasticity in olfactory receptor expression in the honeybee, Apis mellifera. Using quantitative RT-PCR analysis, we show that six putative floral scent receptors were differentially expressed in the bee antennae depending on the scent environment that the bees experienced. Or151, which we characterized using an in vitro cell expression system as a broadly tuned receptor binding floral odorants such as linalool, and Or11, the specific receptor for the queen pheromone 9-oxo-decenoic acid, were significantly down-regulated after honeybees were conditioned with the respective odorants in an olfactory learning paradigm. Electroantennogram recordings showed that the neural response of the antenna was similarly reduced after odor learning. Long-term odor memory was essential for inducing these changes, suggesting that the molecular mechanisms involved in olfactory memory also regulate olfactory receptor expression. Our study demonstrates for the first time that olfactory receptor expression is experience-dependent and modulated by scent conditioning, providing novel insight into how molecular regulation at the periphery contributes to plasticity in the olfactory system. PMID:24628891

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

    PubMed

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

    2012-12-01

    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

  20. Balanced feedforward inhibition and dominant recurrent inhibition in olfactory cortex.

    PubMed

    Large, Adam M; Vogler, Nathan W; Mielo, Samantha; Oswald, Anne-Marie M

    2016-02-23

    Throughout the brain, the recruitment of feedforward and recurrent inhibition shapes neural responses. However, disentangling the relative contributions of these often-overlapping cortical circuits is challenging. The piriform cortex provides an ideal system to address this issue because the interneurons responsible for feedforward and recurrent inhibition are anatomically segregated in layer (L) 1 and L2/3 respectively. Here we use a combination of optical and electrical activation of interneurons to profile the inhibitory input received by three classes of principal excitatory neuron in the anterior piriform cortex. In all classes, we find that L1 interneurons provide weaker inhibition than L2/3 interneurons. Nonetheless, feedforward inhibitory strength covaries with the amount of afferent excitation received by each class of principal neuron. In contrast, intracortical stimulation of L2/3 evokes strong inhibition that dominates recurrent excitation in all classes. Finally, we find that the relative contributions of feedforward and recurrent pathways differ between principal neuron classes. Specifically, L2 neurons receive more reliable afferent drive and less overall inhibition than L3 neurons. Alternatively, L3 neurons receive substantially more intracortical inhibition. These three features--balanced afferent drive, dominant recurrent inhibition, and differential recruitment by afferent vs. intracortical circuits, dependent on cell class--suggest mechanisms for olfactory processing that may extend to other sensory cortices. PMID:26858458

  1. Distinct signaling of Drosophila chemoreceptors in olfactory sensory neurons

    PubMed Central

    Cao, Li-Hui; Jing, Bi-Yang; Yang, Dong; Zeng, Xiankun; Shen, Ying; Tu, Yuhai; Luo, Dong-Gen

    2016-01-01

    In Drosophila, olfactory sensory neurons (OSNs) rely primarily on two types of chemoreceptors, odorant receptors (Ors) and ionotropic receptors (Irs), to convert odor stimuli into neural activity. The cellular signaling of these receptors in their native OSNs remains unclear because of the difficulty of obtaining intracellular recordings from Drosophila OSNs. Here, we developed an antennal preparation that enabled the first recordings (to our knowledge) from targeted Drosophila OSNs through a patch-clamp technique. We found that brief odor pulses triggered graded inward receptor currents with distinct response kinetics and current–voltage relationships between Or- and Ir-driven responses. When stimulated with long-step odors, the receptor current of Ir-expressing OSNs did not adapt. In contrast, Or-expressing OSNs showed a strong Ca2+-dependent adaptation. The adaptation-induced changes in odor sensitivity obeyed the Weber–Fechner relation; however, surprisingly, the incremental sensitivity was reduced at low odor backgrounds but increased at high odor backgrounds. Our model for odor adaptation revealed two opposing effects of adaptation, desensitization and prevention of saturation, in dynamically adjusting odor sensitivity and extending the sensory operating range. PMID:26831094

  2. Vapor Sensors Using Olfactory Proteins Coupled to Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Lerner, Mitchell; Goldsmith, Brett; Mitala, Joe; Discher, Bohdana; Johnson, A. T. Charlie

    2010-03-01

    We have constructed bio-nano devices which combine mammalian olfactory proteins with carbon nanotubes to create a new class of vapor sensors. Olfactory proteins are a specific class of G-protein coupled receptors, and require a cell membrane or similar environment for proper function. Functionalization procedures have been developed to meet the challenges of routinely coupling such membrane proteins to nanotubes, while preserving the function of the protein. We have successfully isolated olfactory proteins and attached them to carbon nanotube transistors, which provide fast, all-electronic readout of analyte binding by the olfactory receptor. Several different olfactory proteins have been tested, each showing a different sensing response. This work opens the way for future coupling of biology to nanoelectronics and improved biomimetic chemical sensing. This work is supported by the DARPA RealNose Project and the Nano/Bio Interface Center

  3. Human Neural Cells Transiently Express Reelin during Olfactory Placode Development

    PubMed Central

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

    2015-01-01

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

  4. Olfactory Cilia: Linking Sensory Cilia Function and Human Disease

    PubMed Central

    Jenkins, Paul M.; McEwen, Dyke P.

    2009-01-01

    The olfactory system gives us an awareness of our immediate environment by allowing us to detect airborne stimuli. The components necessary for detection of these odorants are compartmentalized in the cilia of olfactory sensory neurons. Cilia are microtubule-based organelles, which can be found projecting from the surface of almost any mammalian cell, and are critical for proper olfactory function. Mislocalization of ciliary proteins and/or the loss of cilia cause impaired olfactory function, which is now recognized as a clinical manifestation of a broad class of human diseases, termed ciliopathies. Future work investigating the mechanisms of olfactory cilia function will provide us important new information regarding the pathogenesis of human sensory perception diseases. PMID:19406873

  5. Histochemical study of the olfactory mucosae of the horse.

    PubMed

    Lee, Kwang-Hyup; Park, Changnam; Bang, Hyojin; Ahn, Meejung; Moon, Changjong; Kim, Seungjoon; Shin, Taekyun

    2016-05-01

    The olfactory mucosae of the horse were examined by using histology and lectin histochemistry to characterize the carbohydrate sugar residues therein. Histological findings revealed that olfactory epithelium (OE) consisted of both olfactory marker protein (OMP)- and protein gene product (PGP) 9.5-positive receptor cells, supporting cells and basal cells with intervening secretory ducts from Bowman's glands. Mucus histochemistry showed that Bowman's gland acini contain periodic acid-Schiff (PAS) reagent-positive neutral mucins and alcian blue pH 2.5-positive mucosubstances. Lectin histochemistry revealed that a variety of carbohydrate sugar residues, including N-acetylglucosamine, mannose, galactose, N-acetylgalactosamine, fucose and complex type N-glycan groups, are present in the various cell types in the olfactory mucosa at varying levels. Collectively, this is the first descriptive study of horse olfactory mucosa to characterize carbohydrate sugar residues in the OE and Bowman's glands. PMID:27040092

  6. Humans can discriminate more than 1 trillion olfactory stimuli.

    PubMed

    Bushdid, C; Magnasco, M O; Vosshall, L B; Keller, A

    2014-03-21

    Humans can discriminate several million different colors and almost half a million different tones, but the number of discriminable olfactory stimuli remains unknown. The lay and scientific literature typically claims that humans can discriminate 10,000 odors, but this number has never been empirically validated. We determined the resolution of the human sense of smell by testing the capacity of humans to discriminate odor mixtures with varying numbers of shared components. On the basis of the results of psychophysical testing, we calculated that humans can discriminate at least 1 trillion olfactory stimuli. This is far more than previous estimates of distinguishable olfactory stimuli. It demonstrates that the human olfactory system, with its hundreds of different olfactory receptors, far outperforms the other senses in the number of physically different stimuli it can discriminate. PMID:24653035

  7. 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

  8. Human Neural Cells Transiently Express Reelin during Olfactory Placode Development.

    PubMed

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

    2015-01-01

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

  9. 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

  10. Olfactory cues are subordinate to visual stimuli in a neotropical generalist weevil.

    PubMed

    Otálora-Luna, Fernando; Lapointe, Stephen L; Dickens, Joseph C

    2013-01-01

    The tropical root weevil Diaprepes abbreviatus is a major pest of multiple crops in the Caribbean Islands and has become a serious constraint to citrus production in the United States. Recent work has identified host and conspecific volatiles that mediate host- and mate-finding by D. abbreviatus. The interaction of light, color, and odors has not been studied in this species. The responses of male and female D. abbreviatus to narrow bandwidths of visible light emitted by LEDs offered alone and in combination with olfactory stimuli were studied in a specially-designed multiple choice arena combined with a locomotion compensator. Weevils were more attracted to wavelengths close to green and yellow compared with blue or ultraviolet, but preferred red and darkness over green. Additionally, dim green light was preferred over brighter green. Adult weevils were also attracted to the odor of its citrus host + conspecifics. However, the attractiveness of citrus + conspecific odors disappeared in the presence of a green light. Photic stimulation induced males but not females to increase their speed. In the presence of light emitted by LEDs, turning speed decreased and path straightness increased, indicating that weevils tended to walk less tortuously. Diaprepes abbreviatus showed a hierarchy between chemo- and photo-taxis in the series of experiments presented herein, where the presence of the green light abolished upwind anemotaxis elicited by the pheromone + host plant odor. Insight into the strong responses to visual stimuli of chemically stimulated insects may be provided when the amount of information supplied by vision and olfaction is compared, as the information transmission capacity of compound eyes is estimated to be several orders of magnitude higher compared with the olfactory system. Subordination of olfactory responses by photic stimuli should be considered in the design of strategies aimed at management of such insects. PMID:23341926

  11. Pyrethroids Differentially Alter Voltage-Gated Sodium Channels from the Honeybee Central Olfactory Neurons

    PubMed Central

    Kadala, Aklesso; Charreton, Mercedes; Jakob, Ingrid; Cens, Thierry; Rousset, Matthieu; Chahine, Mohamed; Le Conte, Yves; Charnet, Pierre; Collet, Claude

    2014-01-01

    The sensitivity of neurons from the honey bee olfactory system to pyrethroid insecticides was studied using the patch-clamp technique on central ‘antennal lobe neurons’ (ALNs) in cell culture. In these neurons, the voltage-dependent sodium currents are characterized by negative potential for activation, fast kinetics of activation and inactivation, and the presence of cumulative inactivation during train of depolarizations. Perfusion of pyrethroids on these ALN neurons submitted to repetitive stimulations induced (1) an acceleration of cumulative inactivation, and (2) a marked slowing of the tail current recorded upon repolarization. Cypermethrin and permethrin accelerated cumulative inactivation of the sodium current peak in a similar manner and tetramethrin was even more effective. The slow-down of channel deactivation was markedly dependent on the type of pyrethroid. With cypermethrin, a progressive increase of the tail current amplitude along with successive stimulations reveals a traditionally described use-dependent recruitment of modified sodium channels. However, an unexpected decrease in this tail current was revealed with tetramethrin. If one considers the calculated percentage of modified channels as an index of pyrethroids effects, ALNs are significantly more susceptible to tetramethrin than to permethrin or cypermethrin for a single depolarization, but this difference attenuates with repetitive activity. Further comparison with peripheral neurons from antennae suggest that these modifications are neuron type specific. Modeling the sodium channel as a multi-state channel with fast and slow inactivation allows to underline the effects of pyrethroids on a set of rate constants connecting open and inactivated conformations, and give some insights to their specificity. Altogether, our results revealed a differential sensitivity of central olfactory neurons to pyrethroids that emphasize the ability for these compounds to impair detection and processing

  12. Olfactory Cues Are Subordinate to Visual Stimuli in a Neotropical Generalist Weevil

    PubMed Central

    Otálora-Luna, Fernando; Lapointe, Stephen L.; Dickens, Joseph C.

    2013-01-01

    The tropical root weevil Diaprepes abbreviatus is a major pest of multiple crops in the Caribbean Islands and has become a serious constraint to citrus production in the United States. Recent work has identified host and conspecific volatiles that mediate host- and mate-finding by D. abbreviatus. The interaction of light, color, and odors has not been studied in this species. The responses of male and female D. abbreviatus to narrow bandwidths of visible light emitted by LEDs offered alone and in combination with olfactory stimuli were studied in a specially-designed multiple choice arena combined with a locomotion compensator. Weevils were more attracted to wavelengths close to green and yellow compared with blue or ultraviolet, but preferred red and darkness over green. Additionally, dim green light was preferred over brighter green. Adult weevils were also attracted to the odor of its citrus host + conspecifics. However, the attractiveness of citrus + conspecific odors disappeared in the presence of a green light. Photic stimulation induced males but not females to increase their speed. In the presence of light emitted by LEDs, turning speed decreased and path straightness increased, indicating that weevils tended to walk less tortuously. Diaprepes abbreviatus showed a hierarchy between chemo- and photo-taxis in the series of experiments presented herein, where the presence of the green light abolished upwind anemotaxis elicited by the pheromone + host plant odor. Insight into the strong responses to visual stimuli of chemically stimulated insects may be provided when the amount of information supplied by vision and olfaction is compared, as the information transmission capacity of compound eyes is estimated to be several orders of magnitude higher compared with the olfactory system. Subordination of olfactory responses by photic stimuli should be considered in the design of strategies aimed at management of such insects. PMID:23341926

  13. Axon fasciculation in the developing olfactory nerve

    PubMed Central

    2010-01-01

    Olfactory sensory neuron (OSN) axons exit the olfactory epithelium (OE) and extend toward the olfactory bulb (OB) where they coalesce into glomeruli. Each OSN expresses only 1 of approximately 1,200 odor receptors (ORs). OSNs expressing the same OR are distributed in restricted zones of the OE. However, within a zone, the OSNs expressing a specific OR are not contiguous - distribution appears stochastic. Upon reaching the OB the OSN axons expressing the same OR reproducibly coalesce into two to three glomeruli. While ORs appear necessary for appropriate convergence of axons, a variety of adhesion associated molecules and activity-dependent mechanisms are also implicated. Recent data suggest pre-target OSN axon sorting may influence glomerular convergence. Here, using regional and OR-specific markers, we addressed the spatio-temporal properties associated with the onset of homotypic fasciculation in embryonic mice and assessed the degree to which subpopulations of axons remain segregated as they extend toward the nascent OB. We show that immediately upon crossing the basal lamina, axons uniformly turn sharply, usually at an approximately 90° angle toward the OB. Molecularly defined subpopulations of axons show evidence of spatial segregation within the nascent nerve by embryonic day 12, within 48 hours of the first OSN axons crossing the basal lamina, but at least 72 hours before synapse formation in the developing OB. Homotypic fasciculation of OSN axons expressing the same OR appears to be a hierarchical process. While regional segregation occurs in the mesenchyme, the final convergence of OR-specific subpopulations does not occur until the axons reach the inner nerve layer of the OB. PMID:20723208

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

    PubMed

    Sunderman, F W

    2001-01-01

    Occupational exposures to inhalation of certain metal dusts or aerosols can cause loss of olfactory acuity, atrophy of the nasal mucosa, mucosal ulcers, perforated nasal septum, or sinonasal cancer. Anosmia and hyposmia have been observed in workers exposed to Ni- or Cd-containing dusts in alkaline battery factories, nickel refineries, and cadmium industries. Ulcers of the nasal mucosa and perforated nasal septum have been reported in workers exposed to Cr(VI) in chromate production and chrome plating, or to As(III) in arsenic smelters. Atrophy of the olfactory epithelium has been observed in rodents following inhalation of NiSO4 or alphaNi3S2. Cancers of the nose and nasal sinuses have been reported in workers exposed to Ni compounds in nickel refining, cutlery factories, and alkaline battery manufacture, or to Cr(VI) in chromate production and chrome plating. In animals, several metals (eg, Al, Cd, Co, Hg, Mn, Ni, Zn) have been shown to pass via olfactory receptor neurons from the nasal lumen through the cribriform plate to the olfactory bulb. Some metals (eg, Mn, Ni, Zn) can cross synapses in the olfactory bulb and migrate via secondary olfactory neurons to distant nuclei of the brain. After nasal instillation of a metal-containing solution, transport of the metal via olfactory axons can occur rapidly, within hours or a few days (eg, Mn), or slowly over days or weeks (eg, Ni). The olfactory bulb tends to accumulate certain metals (eg, Al, Bi, Cu, Mn, Zn) with greater avidity than other regions of the brain. The molecular mechanisms responsible for metal translocation in olfactory neurons and deposition in the olfactory bulb are unclear, but complexation by metal-binding molecules such as carnosine (beta-alanyl-L-histidine) may be involved. PMID:11314863

  15. Olfactory impairment and subjective olfactory complaints independently predict conversion to dementia: a longitudinal, population-based study.

    PubMed

    Stanciu, Ingrid; Larsson, Maria; Nordin, Steven; Adolfsson, Rolf; Nilsson, Lars-Göran; Olofsson, Jonas K

    2014-02-01

    We examined whether conversion to dementia can be predicted by self-reported olfactory impairment and/or by an inability to identify odors. Common forms of dementia involve an impaired sense of smell, and poor olfactory performance predicts cognitive decline among the elderly. We followed a sample of 1529 participants, who were within a normal range of overall cognitive function at baseline, over a 10-year period during which 159 were classified as having a dementia disorder. Dementia conversion was predicted from demographic variables, Mini-Mental State Examination score, and olfactory assessments. Self-reported olfactory impairment emerged as an independent predictor of dementia. After adjusting for effects of other predictors, individuals who rated their olfactory sensitivity as "worse than normal" were more likely to convert to dementia than those who reported normal olfactory sensitivity (odds ratio [OR] = 2.17; 95% confidence interval [CI] [1.40, 3.37]). Additionally, low scores on an odor identification test also predicted conversion to dementia (OR per 1 point increase = 0.89; 95% CI [0.81, 0.98]), but these two effects were additive. We suggest that assessing subjective olfactory complaints might supplement other assessments when evaluating the risk of conversion to dementia. Future studies should investigate which combination of olfactory assessments is most useful in predicting dementia conversion. PMID:24451436

  16. FUNCTIONAL DEFICITS PRODUCED BY 3-METHYLINDOLE-INDUCED OLFACTORY MUCOSAL DAMAGE REVEALED BY A SIMPLE OLFACTORY LEARNING TASK

    EPA Science Inventory

    Methods for assessing functional consequences of olfactory mucosal damage were examined in rats exposed to 3-methylindole (3-MI). Treatment with 3-MI (400 mg/kg) induced severe degeneration of olfactory sensory epithelium followed by regeneration, fibrous adhesions and osseous re...

  17. Apropos of an Olfactory Reference Syndrome case.

    PubMed

    Cruzado, Lizardo; Cáceres-Taco, Elisa; Calizaya, Jesús R

    2012-01-01

    Olfactory Reference Syndrome (ORS) is one of the varieties of the somatic type of the Delusional Disorder, and it is characterized by the mistaken statement of a patient who declares the issuance of a foul odor coming from his own body and that others may notice. In the upcoming edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-V) it has been proposed to break off ORS as an independent pathology. From an illustrative case report, we review the relevant literature and discuss this proposal. PMID:22851484

  18. Characterizing the Input-Output Function of the Olfactory-Limbic Pathway in the Guinea Pig.

    PubMed

    Breschi, Gian Luca; Ciliberto, Carlo; Nieus, Thierry; Rosasco, Lorenzo; Taverna, Stefano; Chiappalone, Michela; Pasquale, Valentina

    2015-01-01

    Nowadays the neuroscientific community is taking more and more advantage of the continuous interaction between engineers and computational neuroscientists in order to develop neuroprostheses aimed at replacing damaged brain areas with artificial devices. To this end, a technological effort is required to develop neural network models which can be fed with the recorded electrophysiological patterns to yield the correct brain stimulation to recover the desired functions. In this paper we present a machine learning approach to derive the input-output function of the olfactory-limbic pathway in the in vitro whole brain of guinea pig, less complex and more controllable than an in vivo system. We first experimentally characterized the neuronal pathway by delivering different sets of electrical stimuli from the lateral olfactory tract (LOT) and by recording the corresponding responses in the lateral entorhinal cortex (l-ERC). As a second step, we used information theory to evaluate how much information output features carry about the input. Finally we used the acquired data to learn the LOT-l-ERC "I/O function," by means of the kernel regularized least squares method, able to predict l-ERC responses on the basis of LOT stimulation features. Our modeling approach can be further exploited for brain prostheses applications. PMID:26290660

  19. Phosphodiesterase 1C is dispensable for rapid response termination of olfactory sensory neurons

    PubMed Central

    Cygnar, Katherine D.; Zhao, Haiqing

    2009-01-01

    In the nose, odorants are detected on the cilia of olfactory sensory neurons (OSNs), where a cAMP-mediated signaling pathway transforms odor stimulation into electrical responses. Phosphodiesterase (PDE) activity in OSN cilia was long thought to account for rapid response termination by degrading odor-induced cAMP. Two PDEs with distinct cellular localization have been found in OSNs: PDE1C in cilia; PDE4A throughout the cell but absent from cilia. We disrupted both genes in mice and performed electroolfactogram analysis. Unexpectedly, eliminating PDE1C did not prolong response termination. Prolonged termination occurred only in mice lacking both PDEs, suggesting that cAMP degradation by PDE1C in cilia is not a rate-limiting factor for response termination in wildtype. Pde1c−/− OSNs instead displayed reduced sensitivity and attenuated adaptation to repeated stimulation, suggesting potential roles for PDE1C in regulating sensitivity and adaptation. These observations provide new perspectives in regulation of olfactory transduction. PMID:19305400

  20. Characterizing the Input-Output Function of the Olfactory-Limbic Pathway in the Guinea Pig

    PubMed Central

    Breschi, Gian Luca; Ciliberto, Carlo; Nieus, Thierry; Rosasco, Lorenzo; Taverna, Stefano; Chiappalone, Michela; Pasquale, Valentina

    2015-01-01

    Nowadays the neuroscientific community is taking more and more advantage of the continuous interaction between engineers and computational neuroscientists in order to develop neuroprostheses aimed at replacing damaged brain areas with artificial devices. To this end, a technological effort is required to develop neural network models which can be fed with the recorded electrophysiological patterns to yield the correct brain stimulation to recover the desired functions. In this paper we present a machine learning approach to derive the input-output function of the olfactory-limbic pathway in the in vitro whole brain of guinea pig, less complex and more controllable than an in vivo system. We first experimentally characterized the neuronal pathway by delivering different sets of electrical stimuli from the lateral olfactory tract (LOT) and by recording the corresponding responses in the lateral entorhinal cortex (l-ERC). As a second step, we used information theory to evaluate how much information output features carry about the input. Finally we used the acquired data to learn the LOT-l-ERC “I/O function,” by means of the kernel regularized least squares method, able to predict l-ERC responses on the basis of LOT stimulation features. Our modeling approach can be further exploited for brain prostheses applications. PMID:26290660

  1. Odor-induced cAMP production in Drosophila melanogaster olfactory sensory neurons.

    PubMed

    Miazzi, Fabio; Hansson, Bill S; Wicher, Dieter

    2016-06-15

    Insect odorant receptors are seven transmembrane domain proteins that form cation channels, whose functional properties such as receptor sensitivity are subject to regulation by intracellular signaling cascades. Here, we used the cAMP fluorescent indicator Epac1-camps to investigate the occurrence of odor-induced cAMP production in olfactory sensory neurons (OSNs) of Drosophila melanogaster We show that stimulation of the receptor complex with an odor mixture or with the synthetic agonist VUAA1 induces a cAMP response. Moreover, we show that while the intracellular Ca(2+) concentration influences cAMP production, the OSN-specific receptor OrX is necessary to elicit cAMP responses in Ca(2+)-free conditions. These results provide direct evidence of a relationship between odorant receptor stimulation and cAMP production in olfactory sensory neurons in the fruit fly antenna and show that this method can be used to further investigate the role that this second messenger plays in insect olfaction. PMID:27045092

  2. Glomerular input patterns in the mouse olfactory bulb evoked by retronasal odor stimuli

    PubMed Central

    2013-01-01

    Background Odorant stimuli can access the olfactory epithelium either orthonasally, by inhalation through the external nares, or retronasally by reverse airflow from the oral cavity. There is evidence that odors perceived through these two routes can differ in quality and intensity. We were curious whether such differences might potentially have a neural basis in the peripheral mechanisms of odor coding. To explore this possibility, we compared olfactory receptor input to glomeruli in the dorsal olfactory bulb evoked by orthonasal and retronasal stimulation. Maps of glomerular response were acquired by optical imaging of transgenic mice expressing synaptopHluorin (spH), a fluorescent reporter of presynaptic activity, in olfactory nerve terminals. Results We found that retronasally delivered odorants were able to activate inputs to multiple glomeruli in the dorsal olfactory bulb. The retronasal responses were smaller than orthonasal responses to odorants delivered at comparable concentrations and flow rates, and they displayed higher thresholds and right-shifted dose–response curves. Glomerular maps of orthonasal and retronasal responses were usually well overlapped, with fewer total numbers of glomeruli in retronasal maps. However, maps at threshold could be quite distinct with little overlap. Retronasal responses were also more narrowly tuned to homologous series of aliphatic odorants of varying carbon chain length, with longer chain, more hydrophobic compounds evoking little or no response at comparable vapor levels. Conclusions Several features of retronasal olfaction are possibly referable to the observed properties of glomerular odorant responses. The finding that retronasal responses are weaker and sparser than orthonasal responses is consistent with psychophysical studies showing lower sensitivity for retronasal olfaction in threshold and suprathreshold tests. The similarity and overlap of orthonasal and retronasal odor maps at suprathreshold

  3. A 3'UTR pumilio-binding element directs translational activation in olfactory sensory neurons.

    PubMed

    Kaye, Julia A; Rose, Natalie C; Goldsworthy, Brett; Goga, Andrei; L'Etoile, Noelle D

    2009-01-15

    Prolonged stimulation leads to specific and stable changes in an animal's behavior. In interneurons, this plasticity requires spatial and temporal control of neuronal protein synthesis. Whether such translational control occurs in sensory neurons is not known. Adaptation of the AWC olfactory sensory neurons of C. elegans requires the cGMP-dependent protein kinase EGL-4. Here, we show that the RNA-binding PUF protein FBF-1 is required in the adult AWC for adaptation. In the odor-adapted animal, it increases translation via binding to the egl-4 3' UTR. Further, the PUF protein may localize translation near the sensory cilia and cell body. Although the RNA-binding PUF proteins have been shown to promote plasticity in development by temporally and spatially repressing translation, this work reveals that in the adult nervous system, they can work in a different way to promote experience-dependent plasticity by activating translation in response to environmental stimulation. PMID:19146813

  4. Axon Regeneration Can Facilitate or Suppress Hindlimb Function after Olfactory Ensheathing Glia Transplantation

    PubMed Central

    Takeoka, Aya; Jindrich, Devin L.; Muñoz-Quiles, Cintia; Zhong, Hui; van den Brand, Rubia; Pham, Daniel L.; Ziegler, Matthias D.; Ramón-Cueto, Almudena; Roy, Roland R.; Edgerton, V. Reggie

    2011-01-01

    Reports based primarily on anatomical evidence suggest that olfactory ensheathing glia (OEG) transplantation promotes axon regeneration across a complete spinal cord transection in adult rats. Based on functional, electrophysiological, and anatomical assessments, we found that OEG promoted axon regeneration across a complete spinal cord transection and that this regeneration altered motor responses over time. At 7 months after transection, 70% of OEG-treated rats showed motor-evoked potentials in hindlimb muscles after transcranial electric stimulation. Furthermore, a complete spinal cord retransection performed 8 months after injury demonstrated that this axon regeneration suppressed locomotor performance and decreased the hypersensitive hindlimb withdrawal response to mechanical stimulation. OEG transplantation alone promoted reorganization of lumbosacral locomotor networks and, when combined with long-term training, enhanced some stepping measures. These novel findings demonstrate that OEG promote regeneration of mature axons across a complete transection and reorganization of spinal circuitry, both of which contribute to sensorimotor function. PMID:21411671

  5. Disgust and fear lower olfactory threshold.

    PubMed

    Chan, Kai Qin; Holland, Rob W; van Loon, Ruud; Arts, Roy; van Knippenberg, Ad

    2016-08-01

    Odors provide information regarding the chemical properties of potential environment hazards. Some of this information may be disgust-related (e.g., organic decay), whereas other information may be fear-related (e.g., smoke). Many studies have focused on how disgust and fear, as prototypical avoidant emotions, facilitate the detection of possible threats, but these studies have typically confined to the visual modality. Here, we examine how disgust and fear influence olfactory detection at a particular level-the level at which a subliminal olfactory stimulus crosses into conscious perception, also known as a detection threshold. Here, using psychophysical methods that allow us to test perceptual capabilities directly, we show that one way that disgust (Experiments 1-3) and fear (Experiment 3) facilitate detection is by lowering the amount of physical input that is needed to trigger a conscious experience of that input. This effect is particularly strong among individuals with high disgust sensitivity (Experiments 2-3). Our research suggests that a fundamental way in which avoidant emotions foster threat detection is through lowering perceptual thresholds. (PsycINFO Database Record PMID:27064291

  6. Widespread ectopic expression of olfactory receptor genes

    PubMed Central

    Feldmesser, Ester; Olender, Tsviya; Khen, Miriam; Yanai, Itai; Ophir, Ron; Lancet, Doron

    2006-01-01

    Background Olfactory receptors (ORs) are the largest gene family in the human genome. Although they are expected to be expressed specifically in olfactory tissues, some ectopic expression has been reported, with special emphasis on sperm and testis. The present study systematically explores the expression patterns of OR genes in a large number of tissues and assesses the potential functional implication of such ectopic expression. Results We analyzed the expression of hundreds of human and mouse OR transcripts, via EST and microarray data, in several dozens of human and mouse tissues. Different tissues had specific, relatively small OR gene subsets which had particularly high expression levels. In testis, average expression was not particularly high, and very few highly expressed genes were found, none corresponding to ORs previously implicated in sperm chemotaxis. Higher expression levels were more common for genes with a non-OR genomic neighbor. Importantly, no correlation in expression levels was detected for human-mouse orthologous pairs. Also, no significant difference in expression levels was seen between intact and pseudogenized ORs, except for the pseudogenes of subfamily 7E which has undergone a human-specific expansion. Conclusion The OR superfamily as a whole, show widespread, locus-dependent and heterogeneous expression, in agreement with a neutral or near neutral evolutionary model for transcription control. These results cannot reject the possibility that small OR subsets might play functional roles in different tissues, however considerable care should be exerted when offering a functional interpretation for ectopic OR expression based only on transcription information. PMID:16716209

  7. Recordings from cultured newt olfactory receptor cells.

    PubMed

    Matsumura, Kyohei; Matsumoto, Masahiro; Kurahashi, Takashi; Takeuchi, Hiroko

    2012-05-01

    Freshly dissociated olfactory receptor cells (ORCs) are commonly used in electrophysiological research investigations of the physicochemical mechanisms of olfactory signal transduction. Because the morphology of cultured cells clearly becomes worse over time, the ORCs are examined traditionally within several days after dissociation. However, there has been a major concern that cells are affected soon after dissociation. To gain a better understanding of the reliability of data obtained from solitary cells, we obtained electrical data during the lifetime of single ORCs dissociated from the newt. The time course for the deterioration could be revealed by monitoring the membrane properties during culture. Although the number of living cells that were identified by trypan blue extrusion declined day by day, the remaining cells retained morphology and their fundamental electrical features until day 19. In some cells, the cilia and dendrite were observed until day 21, and the bipolar morphology until day 31. The fundamental features of cell excitation were maintained during culture without showing remarkable changes when they retained morphological features. The results suggest that electrical properties of cells are almost unchanged within several days. Furthermore, the dissociated newt ORCs can be used for several weeks that are almost comparable to the intrinsic lifetime of the ORCs in vivo. PMID:22559969

  8. 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

  9. 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

  10. 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

  11. Olfaction and olfactory-mediated behaviour in psychiatric disease models.

    PubMed

    Huckins, Laura M; Logan, Darren W; Sánchez-Andrade, Gabriela

    2013-10-01

    Rats and mice are the most widely used species for modelling psychiatric disease. Assessment of these rodent models typically involves the analysis of aberrant behaviour with behavioural interactions often being manipulated to generate the model. Rodents rely heavily on their excellent sense of smell and almost all their social interactions have a strong olfactory component. Therefore, experimental paradigms that exploit these olfactory-mediated behaviours are among the most robust available and are highly prevalent in psychiatric disease research. These include tests of aggression and maternal instinct, foraging, olfactory memory and habituation and the establishment of social hierarchies. An appreciation of the way that rodents regulate these behaviours in an ethological context can assist experimenters to generate better data from their models and to avoid common pitfalls. We describe some of the more commonly used behavioural paradigms from a rodent olfactory perspective and discuss their application in existing models of psychiatric disease. We introduce the four olfactory subsystems that integrate to mediate the behavioural responses and the types of sensory cue that promote them and discuss their control and practical implementation to improve experimental outcomes. In addition, because smell is critical for normal behaviour in rodents and yet olfactory dysfunction is often associated with neuropsychiatric disease, we introduce some tests for olfactory function that can be applied to rodent models of psychiatric disorders as part of behavioural analysis. PMID:23604803

  12. A lifetime of neurogenesis in the olfactory system.

    PubMed

    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

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

    PubMed

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

    2013-05-01

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

  14. Non-oscillatory discharges of an F-prostaglandin responsive neuron population in the olfactory bulb-telencephalon transition area in lake whitefish.

    PubMed

    Laberge, F; Hara, T J

    2003-01-01

    Our previous studies on olfactory bulbar responses in salmonid fishes suggest that pheromone signals might be processed by a mechanism distinct from that of other odorants. Using in vivo single-unit and electroencephalographic recordings, we investigated response characteristics of olfactory neurons in lake whitefish, Coregonus clupeaformis, a species characterized by high electrophysiological and behavioral sensitivities to the reproductive pheromone candidates F-prostaglandins. We found a neuron population responsive to F-prostaglandins in the ventromedial brain tissue strip connecting the olfactory bulb to the telencephalon. Of the 64 neurons examined in this area, 33% showed excitatory and 11% inhibitory responses to F-prostaglandins, while 52% were non-responsive to all the stimuli tested. Both phasic and tonic F-prostaglandin neuron response patterns were observed during the 10-s stimulus period; some responses were delayed from the onset of stimulation, and some persisted for a long time following stimulus cessation. This neuron population did not induce synchronized oscillatory waves upon stimulation with F-prostaglandins, despite massive discharges. We demonstrate for the first time that the olfactory bulb-telencephalon area of the brain is a distinct neural structure through which putative reproductive pheromone signals are integrated. Amino acid and F-prostaglandin neuron population discharges have different temporal characteristics, suggesting different processing mechanisms exist for odorant and pheromone signals. The observed sustained neuron discharges may play a role in amplifying pheromone signals required for triggering stereotyped neuroendocrine and/or behavior changes. PMID:12617950

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

    PubMed

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

    2012-12-01

    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

  16. 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

  17. Dendritic Organization of Olfactory Inputs to Medial Amygdala Neurons.

    PubMed

    Keshavarzi, Sepideh; Power, John M; Albers, Eva H H; Sullivan, Robert K S; Sah, Pankaj

    2015-09-23

    The medial amygdala (MeA) is a central hub in the olfactory neural network. It receives vomeronasal information directly from the accessory olfactory bulb (AOB) and main olfactory information largely via odor-processing regions such as the olfactory cortical amygdala (CoA). How these inputs are processed by MeA neurons is poorly understood. Using the GAD67-GFP mouse, we show that MeA principal neurons receive convergent AOB and CoA inputs. Somatically recorded AOB synaptic inputs had slower kinetics than CoA inputs, suggesting that they are electrotonically more distant. Field potential recording, pharmacological manipulation, and Ca(2+) imaging revealed that AOB synapses are confined to distal dendrites and segregated from the proximally located CoA synapses. Moreover, unsynchronized AOB inputs had significantly broader temporal summation that was dependent on the activation of NMDA receptors. These findings show that MeA principal neurons process main and accessory olfactory inputs differentially in distinct dendritic compartments. Significance statement: In most vertebrates, olfactory cues are processed by two largely segregated neural pathways, the main and accessory olfactory systems, which are specialized to detect odors and nonvolatile chemosignals, respectively. Information from these two pathways ultimately converges at higher brain regions, one of the major hubs being the medial amygdala. Little is known about how olfactory inputs are processed by medial amygdala neurons. This study shows that individual principal neurons in this region receive input from both pathways and that these synapses are spatially segregated on their dendritic tree. We provide evidence suggesting that this dendritic segregation leads to distinct input integration and impact on neuronal output; hence, dendritic mechanisms control olfactory processing in the amygdala. PMID:26400933

  18. Face detection for interactive tabletop viewscreen system using olfactory display

    NASA Astrophysics Data System (ADS)

    Sakamoto, Kunio; Kanazawa, Fumihiro

    2009-10-01

    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.

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

    PubMed

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

    2016-07-01

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

  20. Expression of polysialyltransferases (STX and PST) in adult rat olfactory bulb after an olfactory associative discrimination task.

    PubMed

    Mione, J; Manrique, C; Duhoo, Y; Roman, F S; Guiraudie-Capraz, G

    2016-04-01

    Neuronal plasticity and neurogenesis occur in the adult hippocampus and in other brain structures such as the olfactory bulb and often involve the neural cell adhesion molecule NCAM. During an olfactory associative discrimination learning task, NCAM polysialylation triggers neuronal plasticity in the adult hippocampus. The PST enzyme likely modulates this polysialylation, but not STX, a second sialyltransferase. How the two polysialyltransferases are involved in the adult olfactory bulb remains unknown. We addressed this question by investigating the effect of olfactory associative learning on plasticity and neurogenesis. After a hippocampo-dependent olfactory associative task learning, we measured the expression of both PST and STX polysialyltransferases in the olfactory bulbs of adult rats using quantitative PCR. In parallel, immunohistochemistry was used to evaluate both NCAM polysialylation level and newly-born cells, with or without learning. After learning, no changes were observed neither in the expression level of PST and NCAM polysialylation, nor in STX gene expression level and newly-born cells number in the olfactory bulb. PMID:26844880

  1. Carbon Dioxide and Fruit Odor Transduction in Drosophila Olfactory Neurons. What Controls their Dynamic Properties?

    PubMed Central

    French, Andrew S.; Meisner, Shannon; Su, Chih-Ying; Torkkeli, Päivi H.

    2014-01-01

    We measured frequency response functions between odorants and action potentials in two types of neurons in Drosophila antennal basiconic sensilla. CO2 was used to stimulate ab1C neurons, and the fruit odor ethyl butyrate was used to stimulate ab3A neurons. We also measured frequency response functions for light-induced action potential responses from transgenic flies expressing H134R-channelrhodopsin-2 (ChR2) in the ab1C and ab3A neurons. Frequency response functions for all stimulation methods were well-fitted by a band-pass filter function with two time constants that determined the lower and upper frequency limits of the response. Low frequency time constants were the same in each type of neuron, independent of stimulus method, but varied between neuron types. High frequency time constants were significantly slower with ethyl butyrate stimulation than light or CO2 stimulation. In spite of these quantitative differences, there were strong similarities in the form and frequency ranges of all responses. Since light-activated ChR2 depolarizes neurons directly, rather than through a chemoreceptor mechanism, these data suggest that low frequency dynamic properties of Drosophila olfactory sensilla are dominated by neuron-specific ionic processes during action potential production. In contrast, high frequency dynamics are limited by processes associated with earlier steps in odor transduction, and CO2 is detected more rapidly than fruit odor. PMID:24466044

  2. Olfactory Sensory Activity Modulates Microglial-Neuronal Interactions during Dopaminergic Cell Loss in the Olfactory Bulb.

    PubMed

    Grier, Bryce D; Belluscio, Leonardo; Cheetham, Claire E J

    2016-01-01

    The mammalian olfactory bulb (OB) displays robust activity-dependent plasticity throughout life. Dopaminergic (DA) neurons in the glomerular layer (GL) of the OB are particularly plastic, with loss of sensory input rapidly reducing tyrosine hydroxylase (TH) expression and dopamine production, followed by a substantial reduction in DA neuron number. Here, we asked whether microglia participate in activity-dependent elimination of DA neurons in the mouse OB. Interestingly, we found a significant reduction in the number of both DA neurons and their synapses in the OB ipsilateral to the occluded naris (occluded OB) within just 7 days of sensory deprivation. Concomitantly, the volume of the occluded OB decreased, resulting in an increase in microglial density. Microglia in the occluded OB also adopted morphologies consistent with activation. Using in vivo 2-photon imaging and histological analysis we then showed that loss of olfactory input markedly altered microglial-neuronal interactions during the time that DA neurons are being eliminated: both microglial process motility and the frequency of wrapping of DA neuron somata by activated microglia increased significantly in the occluded OB. Furthermore, we found microglia in the occluded OB that had completely engulfed components of DA neurons. Together, our data provide evidence that loss of olfactory input modulates microglial-DA neuron interactions in the OB, thereby suggesting an important role for microglia in the activity-dependent elimination of DA neurons and their synapses. PMID:27471450

  3. Olfactory Sensory Activity Modulates Microglial-Neuronal Interactions during Dopaminergic Cell Loss in the Olfactory Bulb

    PubMed Central

    Grier, Bryce D.; Belluscio, Leonardo; Cheetham, Claire E. J.

    2016-01-01

    The mammalian olfactory bulb (OB) displays robust activity-dependent plasticity throughout life. Dopaminergic (DA) neurons in the glomerular layer (GL) of the OB are particularly plastic, with loss of sensory input rapidly reducing tyrosine hydroxylase (TH) expression and dopamine production, followed by a substantial reduction in DA neuron number. Here, we asked whether microglia participate in activity-dependent elimination of DA neurons in the mouse OB. Interestingly, we found a significant reduction in the number of both DA neurons and their synapses in the OB ipsilateral to the occluded naris (occluded OB) within just 7 days of sensory deprivation. Concomitantly, the volume of the occluded OB decreased, resulting in an increase in microglial density. Microglia in the occluded OB also adopted morphologies consistent with activation. Using in vivo 2-photon imaging and histological analysis we then showed that loss of olfactory input markedly altered microglial-neuronal interactions during the time that DA neurons are being eliminated: both microglial process motility and the frequency of wrapping of DA neuron somata by activated microglia increased significantly in the occluded OB. Furthermore, we found microglia in the occluded OB that had completely engulfed components of DA neurons. Together, our data provide evidence that loss of olfactory input modulates microglial-DA neuron interactions in the OB, thereby suggesting an important role for microglia in the activity-dependent elimination of DA neurons and their synapses. PMID:27471450

  4. Olfactory marker protein gene: its structure and olfactory neuron-specific expression in transgenic mice.

    PubMed Central

    Danciger, E; Mettling, C; Vidal, M; Morris, R; Margolis, F

    1989-01-01

    Olfactory marker protein (OMP) genomic clones were isolated from a Charon 4A phage lambda rat genomic library. A 16.5-kilobase (kb) fragment of the rat genome containing the gene was isolated and characterized. Sequence analysis of the gene showed the absence of introns and the lack of CAAT and TATA boxes in the 5' flanking region. The transcription initiation site was mapped, and two sites 55 and 58 base pairs upstream of the ATG were observed. The 5' flanking region is rich in G+C residues and contains a G+C-rich motif as well as direct and inverted repeats. Functional OMP regulatory sequences were demonstrated in transgenic mice. An 11-kb chimeric gene was constructed in which the coding region for OMP was replaced with that for Thy-1.1. In Thy-1.2 mice carrying this transgene, Thy-1.1 was expressed solely by olfactory receptor neurons and their axons and terminals in the olfactory bulb. Images PMID:2701951

  5. 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

  6. Fault tolerant architecture for artificial olfactory system

    NASA Astrophysics Data System (ADS)

    Lotfivand, Nasser; Nizar Hamidon, Mohd; Abdolzadeh, Vida

    2015-05-01

    In this paper, to cover and mask the faults that occur in the sensing unit of an artificial olfactory system, a novel architecture is offered. The proposed architecture is able to tolerate failures in the sensors of the array and the faults that occur are masked. The proposed architecture for extracting the correct results from the output of the sensors can provide the quality of service for generated data from the sensor array. The results of various evaluations and analysis proved that the proposed architecture has acceptable performance in comparison with the classic form of the sensor array in gas identification. According to the results, achieving a high odor discrimination based on the suggested architecture is possible.

  7. Biophysical mechanisms underlying olfactory receptor neuron dynamics

    PubMed Central

    Nagel, Katherine I.; Wilson, Rachel I.

    2010-01-01

    Odor responses of olfactory receptor neurons (ORNs) exhibit complex dynamics. Using genetics and pharmacology, we show that these dynamics in Drosophila ORNs can be separated into sequential steps, corresponding to transduction and spike generation. Each of these steps contributes distinct dynamics. Transduction dynamics can be largely explained by a simple kinetic model of ligand-receptor interactions, together with an adaptive feedback mechanism that slows transduction onset. Spiking dynamics are well-described by a differentiating linear filter that is stereotyped across odors and cells. Genetic knock-down of sodium channels reshapes this filter, implying that it arises from the regulated balance of intrinsic conductances in ORNs. Complex responses can be understood as a consequence of how the stereotyped spike filter interacts with odor- and receptor-specific transduction dynamics. However, in the presence of rapidly fluctuating natural stimuli, spiking simply increases the speed and sensitivity of encoding. PMID:21217763

  8. 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. PMID:19577476

  9. 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.

  10. 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

  11. Inhibition by Somatostatin Interneurons in Olfactory Cortex.

    PubMed

    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

  12. From the Cover: Odor maps in the olfactory cortex

    NASA Astrophysics Data System (ADS)

    Zou, Zhihua; Li, Fusheng; Buck, Linda B.

    2005-05-01

    In the olfactory system, environmental chemicals are deconstructed into neural signals and then reconstructed to form odor perceptions. Much has been learned about odor coding in the olfactory epithelium and bulb, but little is known about how odors are subsequently encoded in the cortex to yield diverse perceptions. Here, we report that the representation of odors by fixed glomeruli in the olfactory bulb is transformed in the cortex into highly distributed and multiplexed odor maps. In the mouse olfactory cortex, individual odorants are represented by subsets of sparsely distributed neurons. Different odorants elicit distinct, but partially overlapping, patterns that are strikingly similar among individuals. With increases in odorant concentration, the representations expand spatially and include additional cortical neurons. Structurally related odorants have highly related representations, suggesting an underlying logic to the mapping of odor identities in the cortex. odorant receptor | smell

  13. Unravelling the Olfactory Sense: From the Gene to Odor Perception.

    PubMed

    Silva Teixeira, Carla S; Cerqueira, Nuno M F S A; Silva Ferreira, António C

    2016-02-01

    Although neglected by science for a long time, the olfactory sense is now the focus of a panoply of studies that bring new insights and raises interesting questions regarding its functioning. The importance in the clarification of this process is of interest for science, but also motivated by the food and perfume industries boosted by a consumer society with increasingly demands for higher quality standards. In this review, a general overview of the state of art of science regarding the olfactory sense is presented with the main focus on the peripheral olfactory system. Special emphasis will be given to the deorphanization of the olfactory receptors (ORs), a critical issue because the specificity and functional properties of about 90% of human ORs remain unknown mainly due to the difficulties associated with the functional expression of ORs in high yields. PMID:26688501

  14. Properties of odour-binding glycoproteins from rat olfactory epithelium.

    PubMed

    Fesenko, E E; Novoselov, V I; Bystrova, M F

    1988-01-22

    The specific membrane glycoproteins with high affinity for camphor and decanal were isolated from rat olfactory epithelium. Antibodies to these glycoproteins inhibited both the electroolfactogram and the binding of odorants. The enzyme immunoassay has shown these glycoproteins to be present in the olfactory epithelium of rat, mouse, guinea-pig and hamster but not in that of frog and carp. The molecular mass of the odour-binding glycoproteins from rat olfactory epithelium solubilized by Triton X-100 was approx. 140 kDa. They consisted of two subunits (88 and 55 kDa). The 88 kDa subunit was capable of binding odorants. The data obtained suggest that the glycoproteins isolated have some properties that make them plausible candidates for olfactory receptor molecules. PMID:3337807

  15. Responses of the rat olfactory epithelium to retronasal air flow.

    PubMed

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

    2007-03-01

    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 nonpolar, hydrophobic odorants were used. Although 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 nonpolar 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 recordings from olfactory bulb. These results help to explain why human investigations often report differences in the sensation or ability to discriminate odorants presented orthonasally versus retronasally. The results also strongly support the importance of odorant sorption in normal olfactory processes. PMID:17215498

  16. 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

  17. An enigmatic clinical entity: A new case of olfactory schwannoma.

    PubMed

    Manto, Andrea; Manzo, Gaetana; De Gennaro, Angela; Martino, Vincenzo; Buono, Vincenzo; Serino, Antonietta

    2016-06-01

    Olfactory schwannomas, also described as subfrontal or olfactory groove schwannomas, are very rare tumors, whose pathogenesis is still largely debated. We report a case of olfactory schwannoma in a 39-year-old woman who presented with anosmia and headache. The clinical examination did not show lesions in the nose-frontal region and there was no history of neurofibromatosis. Head MRI and CT scan revealed a lobulated extra-axial mass localized in the right anterior cranial fossa that elevated the ipsilateral frontal pole. Bilateral frontal craniotomy demonstrated a tumor strictly attached to the right portion of the cribriform plate that surrounded the right olfactory tract, not clearly identifiable. The immunohistochemical analysis suggested the diagnosis of typical schwannoma. The patient was discharged without any neurological deficit and a four-month postoperative MRI scan of the brain showed no residual or recurrent tumor. PMID:26944065

  18. Olfactory communication among Costa Rican squirrel monkeys: a field study.

    PubMed

    Boinski, S

    1992-01-01

    Behaviors with a possible role in olfactory communication among troop members were investigated as part of a field study on the reproductive and foraging ecology of squirrel monkeys (Saimiri oerstedi) in Costa Rica. All age classes engaged in the olfaction-related behaviors. Apart from olfactory investigation of female genitals by males during the mating season, no other potential olfaction-related behavior (urine wash, branch investigation, rump, chest, back rub and sneeze) exceeded 1% of mean behavioral samples. Assessment of reproduction condition appears to be the primary function of such olfactory investigation of the female genital region. The primary function of urine washing is suggested to be the general communication of reproductive status, possibly facilitating reproductive synchrony. Sneezing, rump, back and chest rubbing do not appear to deposit substances active in olfactory communication. PMID:1306175

  19. Olfactory dysfunction as first presenting symptom of cranial fibrous dysplasia

    PubMed Central

    Tsakiropoulou, Evangelia; Konstantinidis, Iordanis; Chatziavramidis, Angelos; Constantinidis, Jannis

    2013-01-01

    Fibrous dysplasia (FD) is a benign bone disorder presenting with a variety of clinical manifestations. This is the first reported case of anosmia as presenting symptom of FD. We present the case of a 72-year-old female patient with a progressive olfactory dysfunction. Clinical examination revealed evidence of chronic rhinosinusitis; therefore the patient was treated with a course of oral corticosteroids. The patient had no improvement in her olfactory ability and imaging studies were ordered. Bony lesions characteristic of craniofacial FD were found, causing obstruction of the central olfactory pathway. This case emphasises the need to conduct further investigations in patients with rhinosinusitis and olfactory dysfunction especially when they present no response to oral steroid treatment. PMID:23893286

  20. Bilateral Synchronous Ectopic Ethmoid Sinus Olfactory Neuroblastoma: A Case Report.

    PubMed

    Leon-Soriano, Elena; Alfonso, Carolina; Yebenes, Laura; Garcia-Polo, Julio; Lassaletta, Luis; Gavilan, Javier

    2016-01-01

    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

  1. Re-establishment of olfactory and taste functions

    PubMed Central

    Welge-Lüssen, Antje

    2005-01-01

    The incidence of olfactory disorders is appoximately 1-2% and they can seriously impact on the quality of life. Quantitative disorders (hyposmia, anosmia) are distinguished from qualitative disorders (parosmia, phantosmia). Olfactory disorders are classified according to the etiology and therapy is planned according to the underlying pathophysiology. In ENT patients olfactory disorders caused by sinonasal diseases are the most common ones, followed by postviral disorders. Therapy consists of topical and systemic steroids, whereas systemic application seems to be of greater value. It is very difficult to predict the improvement of olfactory function using surgery, moreover, the long term - success in surgery is questionable. Isolated taste disorders are rare and in most often caused by underlying diseases or side effects of medications. A meticulous history is necessary and helps to choose effective treatment. In selected cases zinc might be useful. PMID:22073054

  2. Metacognitive knowledge of olfactory dysfunction in Parkinson's disease.

    PubMed

    White, Theresa L; Sadikot, Abbas F; Djordjevic, Jelena

    2016-04-01

    It is well known that patients with Parkinson's Disease (PD) suffer from olfactory impairments, but it is not clear whether patients are aware of their level of deficit in olfactory functioning. Since PD is a neurodegenerative disorder and its progression may be correlated with olfactory loss (Ansari & Johnson, 1975; but see also Doty, Deems, & Stellar, 1988), it is possible that these patients would be subject to metacognitive errors of over-estimation of olfactory ability (White & Kurtz, 2003). Nineteen non-demented PD patients and 19 age-matched controls were each given an objective measure of olfactory identification (the UPSIT, Doty, Shaman, Kimmelman, & Dann, 1984) and a subjective measure involving a questionnaire that asked them to self-rate both their olfactory function generally and their ability to smell each of 20 odors, 12 of which were assessed on the UPSIT. All of the PD patients showed impaired olfactory ability, as did 7 of the controls, according to the UPSIT norms. Self-rated and performance-based olfactory ability scores were significantly correlated in controls (r=.49, p=.03) but not in patients with PD (r=.20, p=.39). When the 12 odors common to both the self-rated questionnaire and UPSIT were compared, PD patients were less accurate than controls (t(36)=-4.96, p<.01) at estimating their own ability and the number of over-estimation errors was significantly higher (tone-tailed(29)=1.80, p=.04) in PD patients than in the control group, showing less metacognitive awareness of their ability than controls. These results support the idea that olfactory metacognition is often impaired in PD, as well as in controls recruited for normosmic ability (Wehling, Nordin, Espeseth, Reinvang, & Lundervold, 2011), and indicate that people with PD generally exhibit over-estimation of their olfactory ability at a rate that is higher than controls. These findings imply that PD patients, unaware of their olfactory deficit, are at greater risk of harm normally

  3. Evidence of a novel transduction pathway mediating detection of polyamines by the zebrafish olfactory system.

    PubMed

    Michel, W C; Sanderson, M J; Olson, J K; Lipschitz, D L

    2003-05-01

    To better understand the full extent of the odorant detection capabilities of fish, we investigated the olfactory sensitivity of zebrafish to a monoamine and several polyamines using electrophysiological and activity-dependent labeling techniques. Electro-olfactogram (EOG) recording methods established the relative stimulatory effectiveness of these odorants as: spermine > spermidine approximately agmatine > glutamine > putrescine >or= cadaverine >or= histamine > artificial freshwater. The detection threshold for the potent polyamines was approximately 1 micromol l(-1). Cross-adaptation experiments suggested that multiple receptors are involved in polyamine detection. Three observations indicated that polyamine signaling may involve a transduction cascade distinct from those used by either amino acids or bile salts. Like bile salts and the adenylate cyclase activator forskolin, but unlike amino acid odorants, polyamines failed to stimulate activity-dependent labeling of olfactory sensory neurons with the cation channel permeant probe agmatine, suggesting a signaling pathway different from that used by amino acid stimuli. Also supporting distinct amino acid and polyamine signaling pathways is the finding that altering phospholipase C activity with the inhibitor U-73122 significantly reduced amino acid-evoked responses, but had little effect on polyamine- (or bile salt-) evoked responses. Altering cyclic nucleotide-mediated signaling by adenylate cyclase activation with forskolin, which significantly reduced responses to bile salts, failed to attenuate polyamine responses, suggesting that polyamines and bile salts do not share a common transduction cascade. Collectively, these findings suggest that polyamines are a new class of olfactory stimuli transduced by a receptor-mediated, second messenger signaling pathway that is distinct from those used by amino acids or bile salts. PMID:12682101

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

    PubMed

    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

  5. Determinants of human olfactory performance: a cross-cultural study.

    PubMed

    Sorokowska, Agnieszka; Sorokowski, Piotr; Frackowiak, Tomasz

    2015-02-15

    Olfaction allows us to detect subtle changes in our environment, but sensitivity of the sense of smell varies among individuals. Although a significant number of research papers discuss the relationship between olfactory abilities and environmental factors, most studies have been conducted on Western populations or in developed Asian societies. The potential environmental and cultural determinants of olfactory acuity warrant further exploration. In the current study, we compared previously published data on olfaction in an industrialized, modern society (i.e., Europeans) and an indigenous society living in unpolluted, natural environmental conditions (i.e., Tsimane'), with novel data on the olfactory acuity of inhabitants of the Cook Islands. Like the European population (and contrary to the Tsimane'), the Cook Islands people form a modern society, and like the Tsimane' population (and contrary to the Europeans), they live in an unpolluted region. Thus, these comparisons enabled us to independently assess the importance of both air pollution and changes in lifestyle for olfactory abilities in modern societies. Our results indicate that people from the Cook Islands had significantly higher olfactory acuity (i.e., lower thresholds of odor detection) than did Europeans and Tsimane' people. Interestingly, the olfactory sensitivity of Europeans was significantly lower than the olfactory sensitivity of the remaining two groups. Our data suggest that air pollution is an important factor in the deterioration of the sense of smell. However, it is also possible that factors such as agricultural and/or cooking practices, alcohol consumption, and access to medical service may also influence olfactory acuity. PMID:25460952

  6. Neural crest and placode contributions to olfactory development.

    PubMed

    Suzuki, Jun; Osumi, Noriko

    2015-01-01

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

  7. 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

  8. 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. PMID:22156550

  9. Olfactory System Involvement in Natural Scrapie Disease ▿

    PubMed Central

    Corona, Cristiano; Porcario, Chiara; Martucci, Francesca; Iulini, Barbara; Manea, Barbara; Gallo, Marina; Palmitessa, Claudia; Maurella, Cristiana; Mazza, Maria; Pezzolato, Marzia; Acutis, Pierluigi; Casalone, Cristina

    2009-01-01

    The olfactory system (OS) is involved in many infectious and neurodegenerative diseases, both human and animal, and it has recently been investigated in regard to transmissible spongiform encephalopathies. Previous assessments of nasal mucosa infection by prions following intracerebral challenge suggested a potential centrifugal spread along the olfactory nerve fibers of the pathological prion protein (PrPSc). Whether the nasal cavity may be a route for centripetal prion infection to the brain has also been experimentally studied. With the present study, we wanted to determine whether prion deposition in the OS occurs also under field conditions and what type of anatomical localization PrPSc might display there. We report here on detection by different techniques of PrPSc in the nasal mucosa and in the OS-related brain areas of sheep affected by natural scrapie. PrPSc was detected in the perineurium of the olfactory nerve bundles in the medial nasal concha and in nasal-associated lymphoid tissue. Olfactory receptor neurons did not show PrPSc immunostaining. PrPSc deposition was found in the brain areas of olfactory fiber projection, chiefly in the olfactory bulb and the olfactory cortex. The prevalent PrPSc deposition patterns were subependymal, perivascular, and submeningeal. This finding, together with the discovery of an intense PrPSc immunostaining in the meningeal layer of the olfactory nerve perineurium, at the border with the subdural space extension surrounding the nerve rootlets, strongly suggests a probable role of cerebrospinal fluid in conveying prion infectivity to the nasal submucosa. PMID:19158242

  10. 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

  11. Multidimensional representation of odors in the human olfactory cortex.

    PubMed

    Fournel, A; Ferdenzi, C; Sezille, C; Rouby, C; Bensafi, M

    2016-06-01

    What is known as an odor object is an integrated representation constructed from physical features, and perceptual attributes mainly mediated by the olfactory and trigeminal systems. The aim of the present study was to comprehend how this multidimensional representation is organized, by deciphering how similarities in the physical, olfactory and trigeminal perceptual spaces of odors are represented in the human brain. To achieve this aim, we combined psychophysics, functional MRI and multivariate representational similarity analysis. Participants were asked to smell odors diffused by an fMRI-compatible olfactometer and to rate each smell along olfactory dimensions (pleasantness, intensity, familiarity and edibility) and trigeminal dimensions (irritation, coolness, warmth and pain). An event-related design was implemented, presenting different odorants. Results revealed that (i) pairwise odorant similarities in anterior piriform cortex (PC) activity correlated with pairwise odorant similarities in chemical properties (P < 0.005), (ii) similarities in posterior PC activity correlated with similarities in olfactory perceptual properties (P <0.01), and (iii) similarities in amygdala activity correlated with similarities in trigeminal perceptual properties (P < 0.01). These findings provide new evidence that extraction of physical, olfactory and trigeminal features is based on specific fine processing of similarities between odorous stimuli in a distributed manner in the olfactory system. Hum Brain Mapp 37:2161-2172, 2016. © 2016 Wiley Periodicals, Inc. PMID:26991044

  12. 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

  13. Illuminating odors: when optogenetics brings to light unexpected olfactory abilities.

    PubMed

    Grimaud, Julien; Lledo, Pierre-Marie

    2016-06-01

    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

  14. Intracellular trafficking of a tagged and functional mammalian olfactory receptor.

    PubMed

    Ivic, Lidija; Zhang, Cen; Zhang, Xinmin; Yoon, Sung Ok; Firestein, Stuart

    2002-01-01

    Tagged G-protein-coupled receptors (GPCRs) have been used to facilitate intracellular visualization of these receptors. We have used a combination of adenoviral vector gene transfer and tagged olfactory receptors to help visualize mammalian olfactory receptor proteins in the normal olfactory epithelium of rats, and in cell culture. Three recombinant adenoviral vectors were generated carrying variously tagged versions of rat olfactory receptor I7. The constructs include an N-terminal Flag epitope tag (Flag:I7), enhanced green fluorescent protein (EGFP) fusion protein (EGFP:I7), and a C-terminal EGFP fusion (I7:EGFP). These receptor constructs were assayed in rat olfactory sensory neurons (OSNs) and in a heterologous system (HEK 293 cell line) for protein localization and functional expression. Functional expression of the tagged receptor proteins was tested by electroolfactogram (EOG) recordings in the infected rat olfactory epithelium, and by calcium imaging in single cells. Our results demonstrate that the I7:EGFP fusion protein and Flag:I7 are functionally expressed in OSNs while the EGFP:I7 fusion is not, probably due to inappropriate processing of the protein in the cells. These data suggest that a small epitope tag (Flag) at the N-terminus, or EGFP located at the C-terminus of the receptor, does not affect ligand binding or downstream signaling. In addition, both functional fusion proteins (Flag:I7 and I7:EGFP) are properly targeted to the plasma membrane of HEK 293 cells. PMID:11748633

  15. 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.

  16. Plasticity of Glomeruli and Olfactory-Mediated Behavior in Zebrafish Following Detergent Lesioning of the Olfactory Epithelium

    PubMed Central

    White, Evan J.; Kounelis, Savannah K.; Byrd-Jacobs, Christine A.

    2014-01-01

    The zebrafish olfactory system is a valuable model for examining neural regeneration after damage due to the remarkable plasticity of this sensory system and of fish species. We applied detergent to the olfactory organ and examined the effects on both morphology and function of the olfactory system in adult zebrafish. Olfactory organs were treated once with Triton X-100 unilaterally to study glomerular innervation patterns or bilaterally to study odor detection. Fish were allowed to recover for 4–10 days and were compared to untreated control fish. Axonal projections were analyzed using whole mount immunocytochemistry with anti-keyhole limpet hemocyanin, a marker of olfactory axons in teleosts. Chemical lesioning of the olfactory organ with a single dose of Triton X-100 had profound effects on glomerular distribution in the olfactory bulb at 4 days after treatment, with the most significant effects in the medial region of the bulb. Glomeruli had returned by 7 days post-treatment. Analysis of the ability of the fish to detect cocktails of amino acids or bile salts consisted of counting the number of turns the fish made before and after odorant delivery. Control fish turned more after exposure to both odorants. Fish tested 4 and 7 days after chemical lesioning made more turns in response to amino acids but did not respond to bile salts. At 10 days post-lesion, these fish had regained the ability to detect bile salts. Thus, the changes seen in bulbar innervation patterns correlated to odorant-mediated behavior. We show that the adult zebrafish brain has the capacity to recover rapidly from detergent damage of the olfactory epithelium, with both glomerular distribution and odorant-mediated behavior returning in 10 days. PMID:25450960

  17. Plasticity of glomeruli and olfactory-mediated behavior in zebrafish following detergent lesioning of the olfactory epithelium.

    PubMed

    White, E J; Kounelis, S K; Byrd-Jacobs, C A

    2015-01-22

    The zebrafish olfactory system is a valuable model for examining neural regeneration after damage due to the remarkable plasticity of this sensory system and of fish species. We applied detergent to the olfactory organ and examined the effects on both morphology and function of the olfactory system in adult zebrafish. Olfactory organs were treated once with Triton X-100 unilaterally to study glomerular innervation patterns or bilaterally to study odor detection. Fish were allowed to recover for 4-10 days and were compared to untreated control fish. Axonal projections were analyzed using whole mount immunocytochemistry with anti-keyhole limpet hemocyanin, a marker of olfactory axons in teleosts. Chemical lesioning of the olfactory organ with a single dose of Triton X-100 had profound effects on glomerular distribution in the olfactory bulb at 4 days after treatment, with the most significant effects in the medial region of the bulb. Glomeruli had returned by 7 days post-treatment. Analysis of the ability of the fish to detect cocktails of amino acids or bile salts consisted of counting the number of turns the fish made before and after odorant delivery. Control fish turned more after exposure to both odorants. Fish tested 4 and 7 days after chemical lesioning made more turns in response to amino acids but did not respond to bile salts. At 10 days post-lesion, these fish had regained the ability to detect bile salts. Thus, the changes seen in bulbar innervation patterns correlated to odorant-mediated behavior. We show that the adult zebrafish brain has the capacity to recover rapidly from detergent damage of the olfactory epithelium, with both glomerular distribution and odorant-mediated behavior returning in 10 days. PMID:25450960

  18. A Pilot Clinical Study of Olfactory Mucosa Autograft for Chronic Complete Spinal Cord Injury

    PubMed Central

    IWATSUKI, Koichi; TAJIMA, Fumihiro; OHNISHI, Yu-ichiro; NAKAMURA, Takeshi; ISHIHARA, Masahiro; HOSOMI, Koichi; NINOMIYA, Koshi; MORIWAKI, Takashi; YOSHIMINE, Toshiki

    2016-01-01

    Recent studies of spinal cord axon regeneration have reported good long-term results using various types of tissue scaffolds. Olfactory tissue allows autologous transplantation and can easily be obtained by a simple biopsy that is performed through the external nares. We performed a clinical pilot study of olfactory mucosa autograft (OMA) for chronic complete spinal cord injury in eight patients according to the procedure outlined by Lima et al. Our results showed no serious adverse events and improvement in both the American Spinal Injury Association (ASIA) Impairment Scale (AIS) grade and ASIA motor score in five patients. The preoperative post-rehabilitation ASIA motor score improved from 50 in all cases to 52 in case 2, 60 in case 4, 52 in case 6, 55 in case 7, and 58 in case 8 at 96 weeks after OMA. The AIS improved from A to C in four cases and from B to C in one case. Motor evoked potentials (MEPs) were also seen in one patient, reflecting conductivity in the central nervous system, including the corticospinal tract. The MEPs induced with transcranial magnetic stimulation allow objective assessment of the integrity of the motor circuitry comprising both the corticospinal tract and the peripheral motor nerves.We show the feasibility of OMA for chronic complete spinal cord injury. PMID:27053327

  19. A Review of Current Neuromorphic Approaches for Vision, Auditory, and Olfactory Sensors

    PubMed Central

    Vanarse, Anup; Osseiran, Adam; Rassau, Alexander

    2016-01-01

    Conventional vision, auditory, and olfactory sensors generate large volumes of redundant data and as a result tend to consume excessive power. To address these shortcomings, neuromorphic sensors have been developed. These sensors mimic the neuro-biological architecture of sensory organs using aVLSI (analog Very Large Scale Integration) and generate asynchronous spiking output that represents sensing information in ways that are similar to neural signals. This allows for much lower power consumption due to an ability to extract useful sensory information from sparse captured data. The foundation for research in neuromorphic sensors was laid more than two decades ago, but recent developments in understanding of biological sensing and advanced electronics, have stimulated research on sophisticated neuromorphic sensors that provide numerous advantages over conventional sensors. In this paper, we review the current state-of-the-art in neuromorphic implementation of vision, auditory, and olfactory sensors and identify key contributions across these fields. Bringing together these key contributions we suggest a future research direction for further development of the neuromorphic sensing field. PMID:27065784

  20. Contribution of the receptor guanylyl cyclase GC-D to chemosensory function in the olfactory epithelium

    PubMed Central

    Leinders-Zufall, Trese; Cockerham, Renee E.; Michalakis, Stylianos; Biel, Martin; Garbers, David L.; Reed, Randall R.; Zufall, Frank; Munger, Steven D.

    2007-01-01

    The mammalian main olfactory epithelium (MOE) recognizes and transduces olfactory cues through a G protein-coupled, cAMP-dependent signaling cascade. Additional chemosensory transduction mechanisms have been suggested but remain controversial. We show that a subset of MOE neurons expressing the orphan receptor guanylyl cyclase GC-D and the cyclic nucleotide-gated channel subunit CNGA3 employ an excitatory cGMP-dependent transduction mechanism for chemodetection. By combining gene targeting of Gucy2d, which encodes GC-D, with patch clamp recording and confocal Ca2+ imaging from single dendritic knobs in situ, we find that GC-D cells recognize the peptide hormones uroguanylin and guanylin as well as natural urine stimuli. These molecules stimulate an excitatory, cGMP-dependent signaling cascade that increases intracellular Ca2+ and action potential firing. Responses are eliminated in both Gucy2d- and Cnga3-null mice, demonstrating the essential role of GC-D and CNGA3 in the transduction of these molecules. The sensitive and selective detection of two important natriuretic peptides by the GC-D neurons suggests the possibility that these cells contribute to the maintenance of salt and water homeostasis or the detection of cues related to hunger, satiety, or thirst. PMID:17724338

  1. A Review of Current Neuromorphic Approaches for Vision, Auditory, and Olfactory Sensors.

    PubMed

    Vanarse, Anup; Osseiran, Adam; Rassau, Alexander

    2016-01-01

    Conventional vision, auditory, and olfactory sensors generate large volumes of redundant data and as a result tend to consume excessive power. To address these shortcomings, neuromorphic sensors have been developed. These sensors mimic the neuro-biological architecture of sensory organs using aVLSI (analog Very Large Scale Integration) and generate asynchronous spiking output that represents sensing information in ways that are similar to neural signals. This allows for much lower power consumption due to an ability to extract useful sensory information from sparse captured data. The foundation for research in neuromorphic sensors was laid more than two decades ago, but recent developments in understanding of biological sensing and advanced electronics, have stimulated research on sophisticated neuromorphic sensors that provide numerous advantages over conventional sensors. In this paper, we review the current state-of-the-art in neuromorphic implementation of vision, auditory, and olfactory sensors and identify key contributions across these fields. Bringing together these key contributions we suggest a future research direction for further development of the neuromorphic sensing field. PMID:27065784

  2. Specificity and sensitivity of the olfactory organ of the zebrafish, Danio rerio.

    PubMed

    Michel, W C; Lubomudrov, L M

    1995-01-01

    1. The specificity and sensitivity of the olfactory organ of adult zebrafish, Danio rerio, to selected amino acid, bile acid, and steroid odorants were characterized using the electro-olfactogram recording technique. The olfactory organ was responsive to 28 of the 29 odorants tested. 2. All of the 100 microM amino acid and bile acid stimulants elicited a negative-going response that was significantly greater than the response to the artificial fresh-water control. The general pattern of relative stimulatory effectiveness established for the amino acid stimuli was neutral amino acids > basic amino acids > acidic amino acids > imino acids. The general pattern of relative stimulatory effectiveness of 100 microM bile acid stimuli was taurine-conjugated bile acids > glycine-conjugated bile acids approximately non-conjugated bile acids. The responses to the most stimulatory bile acid odorants were up to 40% larger than the responses to the most stimulatory amino acid odorants. 3. The response threshold for cysteine and taurocholic acid, the most stimulatory of the amino acid and bile acid stimuli tested, was approximately 10(-8) M. Females are significantly more sensitive to these odorants than males. PMID:7636767

  3. Odour discrimination in the olfactory bulb of goldfish: contrasting interactions between mitral cells and ruffed cells.

    PubMed

    Zippel, H P; Gloger, M; Nasser, S; Wilcke, S

    2000-09-29

    Anatomical differences characterizing mitral cells and ruffed cells have been published by T. Kosaka and K. Hama in three teleost species. Physiological responses from both types of relay neurons were recorded extracellularly and simultaneously in the plexiform layer, using a single tungsten microelectrode. During interstimulus intervals mitral cells responded with higher, frequently burst-like impulse rates triggered by the activity of epithelial receptor neurons. Mitral cell activity could be totally suppressed by local anaesthesia of the olfactory epithelium. Ruffed cell impulse rates were low, and each action potential triggered a long-lasting (3-5 ms), continuously varying, summed granule cell potential. During olfactory stimulation with non-familiar stimuli and important biological stimuli such as amino acids, preovulatory and ovulatory pheromones, and a probable alarm pheromone, contrasting interactions between mitral cells and ruffed cells were recorded frequently, which resulted in a drastic intensification of centrally transmitted information. An excitation of mitral cells' activity via granule cells laterally inhibited the ruffed cells' activity, and an inhibition of mitral cells' activity simultaneously 'released' an excitation of ruffed cells. PMID:11079404

  4. Role of Go/i subgroup of G proteins in olfactory signaling of Drosophila melanogaster

    PubMed Central

    Ignatious Raja, Jennifer S; Katanayeva, Natalya; Katanaev, Vladimir L; Galizia, C Giovanni

    2014-01-01

    Intracellular signaling in insect olfactory receptor neurons remains unclear, with both metabotropic and ionotropic components being discussed. Here, we investigated the role of heterotrimeric Go and Gi proteins using a combined behavioral, in vivo and in vitro approach. Specifically, we show that inhibiting Go in sensory neurons by pertussis toxin leads to behavioral deficits. We heterologously expressed the olfactory receptor dOr22a in human embryonic kidney cells (HEK293T). Stimulation with an odor led to calcium influx, which was amplified via calcium release from intracellular stores. Subsequent experiments indicated that the signaling was mediated by the Gβγ subunits of the heterotrimeric Go/i proteins. Finally, using in vivo calcium imaging, we show that Go and Gi contribute to odor responses both for the fast (phasic) as for the slow (tonic) response component. We propose a transduction cascade model involving several parallel processes, in which the metabotropic component is activated by Go and Gi, and uses Gβγ. PMID:24443946

  5. Functional organization of glomerular maps in the mouse accessory olfactory bulb

    PubMed Central

    Hammen, Gary F.; Turaga, Diwakar; Holy, Timothy E.; Meeks, Julian P.

    2014-01-01

    Summary The mammalian accessory olfactory system (AOS) extracts information about species, sex, and individual identity from social odors, but its functional organization remains unclear. We imaged presynaptic Ca2+ signals in vomeronasal inputs to the accessory olfactory bulb (AOB) during peripheral stimulation using light sheet microscopy. Urine- and steroid-responsive glomeruli densely innervated the anterior AOB. Glomerular activity maps for sexually mature female mouse urine overlapped maps for juvenile and/or gonadectomized urine of both sexes, whereas maps for sexually mature male urine were highly distinct. Further spatial analysis revealed a complicated organization involving selective juxtaposition and dispersal of functionally-grouped glomerular classes. Glomeruli that were similarly tuned to urines were often closely associated, whereas more disparately tuned glomeruli were selectively dispersed. Maps to a panel of sulfated steroid odorants identified tightly-juxtaposed groups that were disparately tuned and dispersed groups that were similarly tuned. These results reveal a modular, non-chemotopic spatial organization in the AOB. PMID:24880215

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

    PubMed Central

    Lado, Wudu E.; Spanswick, David C.; Lewis, John E.; Trudeau, Vance L.

    2014-01-01

    Chemical communication via sex pheromones is critical for successful reproduction but the underlying neural mechanisms are not well-understood. The goldfish is a tractable model because sex pheromones have been well-characterized in this species. We used male goldfish forebrain explants in vitro and performed whole-cell current clamp recordings from single neurons in the ventral preoptic area (vPOA) to characterize their membrane properties and synaptic inputs from the olfactory bulbs (OB). Principle component and cluster analyses based on intrinsic membrane properties of vPOA neurons (N = 107) revealed five (I–V) distinct cell groups. These cells displayed differences in their input resistance (Rinput: I < II < IV < III = V), time constant (TC: I = II < IV < III = V), and threshold current (Ithreshold: I > II = IV > III = V). Evidence from electrical stimulation of the OB and application of receptor antagonists suggests that vPOA neurons receive monosynaptic glutamatergic inputs via the medial olfactory tract, with connectivity varying among neuronal groups [I (24%), II (40%), III (0%), IV (34%), and V (2%)]. PMID:25071430

  7. A Pilot Clinical Study of Olfactory Mucosa Autograft for Chronic Complete Spinal Cord Injury.

    PubMed

    Iwatsuki, Koichi; Tajima, Fumihiro; Ohnishi, Yu-Ichiro; Nakamura, Takeshi; Ishihara, Masahiro; Hosomi, Koichi; Ninomiya, Koshi; Moriwaki, Takashi; Yoshimine, Toshiki

    2016-06-15

    Recent studies of spinal cord axon regeneration have reported good long-term results using various types of tissue scaffolds. Olfactory tissue allows autologous transplantation and can easily be obtained by a simple biopsy that is performed through the external nares. We performed a clinical pilot study of olfactory mucosa autograft (OMA) for chronic complete spinal cord injury in eight patients according to the procedure outlined by Lima et al. Our results showed no serious adverse events and improvement in both the American Spinal Injury Association (ASIA) Impairment Scale (AIS) grade and ASIA motor score in five patients. The preoperative post-rehabilitation ASIA motor score improved from 50 in all cases to 52 in case 2, 60 in case 4, 52 in case 6, 55 in case 7, and 58 in case 8 at 96 weeks after OMA. The AIS improved from A to C in four cases and from B to C in one case. Motor evoked potentials (MEPs) were also seen in one patient, reflecting conductivity in the central nervous system, including the corticospinal tract. The MEPs induced with transcranial magnetic stimulation allow objective assessment of the integrity of the motor circuitry comprising both the corticospinal tract and the peripheral motor nerves.We show the feasibility of OMA for chronic complete spinal cord injury. PMID:27053327

  8. 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. PMID:26254553

  9. Laterodorsal tegmentum interneuron subtypes oppositely regulate olfactory cue-induced innate fear.

    PubMed

    Yang, Hongbin; Yang, Junhua; Xi, Wang; Hao, Sijia; Luo, Benyan; He, Xiaobin; Zhu, Liya; Lou, Huifang; Yu, Yan-qin; Xu, Fuqiang; Duan, Shumin; Wang, Hao

    2016-02-01

    Innate fear has a critical role in survival of animals. Unlike conditioned fear, the neuronal circuitry underlying innate fear is largely unknown. We found that the laterodorsal tegmentum (LDT) and lateral habenula (LHb) are specifically activated by the mouse predator odorant trimethylthiazoline (TMT). Using optogenetics to selectively stimulate GABAergic neurons in the LDT immediately produced fear-like responses (freezing, accelerated heart rate and increased serum corticosterone), whereas prolonged stimulation caused anxiety-like behaviors. Notably, although selective stimulation of parvalbumin (PV)-positive interneurons similarly induced fear-like responses, stimulation of somatostatin-positive interneurons or inhibition of PV neurons in the LDT suppressed TMT-induced fear-like responses without affecting conditioned fear. Finally, activation of LHb glutamatergic inputs to LDT interneurons was sufficient to generate fear-like responses. Thus, the LHb-LDT pathway is important for regulating olfactory cue-induced innate fear. Our results provide a potential target for therapeutic intervention for anxiety disorder. PMID:26727549

  10. 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

  11. 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

    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

  12. Failure to Obtain Reinstatement of an Olfactory Representation.

    PubMed

    Mahmut, Mehmet K; Stevenson, Richard J

    2015-11-01

    It has long been suspected that attentional processes differ between olfaction and the other senses. Here, we test whether voluntary dishabituation, seen, for example, when we re-attend to the ticking of a clock, can occur in olfaction. Participants were seated in an odorized room, where at various intervals they had to evaluate what they could smell. An experimental group had one nostril open and the other closed, except during the evaluations, so that the closed side was subject to centrally driven habituation, but not peripheral adaptation. A control group had both nostrils closed except during evaluations. Following exposure, the experimental group could not report the room's odor in either the centrally habituated nostril (i.e., that remained closed) or the nostril that remained open, while the control group could. This effect could result from a number of causes, including olfaction's unique neuroanatomy, functional constraints imposed by detecting volatile chemicals, and as a consequence of limited cortical resources, with implications for the functional value of consciousness. PMID:25782607

  13. Electrophysiological Evidence for a Direct Link between the Main and Accessory Olfactory Bulbs in the Adult Rat

    PubMed Central

    Vargas-Barroso, Victor; Ordaz-Sánchez, Benito; Peña-Ortega, Fernando; Larriva-Sahd, Jorge A.

    2016-01-01

    It is accepted that the main- and accessory- olfactory systems exhibit overlapping responses to pheromones and odorants. We performed whole-cell patch-clamp recordings in adult rat olfactory bulb slices to define a possible interaction between the first central relay of these systems: the accessory olfactory bulb (AOB) and the main olfactory bulb (MOB). This was tested by applying electrical field stimulation in the dorsal part of the MOB while recording large principal cells (LPCs) of the anterior AOB (aAOB). Additional recordings of LPCs were performed at either side of the plane of intersection between the aAOB and posterior-AOB (pAOB) halves, or linea alba, while applying field stimulation to the opposite half. A total of 92 recorded neurons were filled during whole-cell recordings with biocytin and studied at the light microscope. Neurons located in the aAOB (n = 6, 8%) send axon collaterals to the MOB since they were antidromically activated in the presence of glutamate receptor antagonists (APV and CNQX). Recorded LPCs evoked orthodromic excitatory post-synaptic responses (n = 6, aAOB; n = 1, pAOB) or antidromic action potentials (n = 8, aAOB; n = 7, pAOB) when applying field stimulation to the opposite half of the recording site (e.g., recording in aAOB; stimulating in pAOB, and vice-versa). Observation of the filled neurons revealed that indeed, LPCs send axon branches that cross the linea alba to resolve in the internal cellular layer. Additionally, LPCs of the aAOB send axon collaterals to dorsal-MOB territory. Notably, while performing AOB recordings we found a sub-population of neurons (24% of the total) that exhibited voltage-dependent bursts of action potentials. Our findings support the existence of: 1. a direct projection from aAOB LPCs to dorsal-MOB, 2. physiologically active synapses linking aAOB and pAOB, and 3. pacemaker-like neurons in both AOB halves. This work was presented in the form of an Abstract on SfN 2014 (719.14/EE17). PMID:26858596

  14. Electrophysiological Evidence for a Direct Link between the Main and Accessory Olfactory Bulbs in the Adult Rat.

    PubMed

    Vargas-Barroso, Victor; Ordaz-Sánchez, Benito; Peña-Ortega, Fernando; Larriva-Sahd, Jorge A

    2015-01-01

    It is accepted that the main- and accessory- olfactory systems exhibit overlapping responses to pheromones and odorants. We performed whole-cell patch-clamp recordings in adult rat olfactory bulb slices to define a possible interaction between the first central relay of these systems: the accessory olfactory bulb (AOB) and the main olfactory bulb (MOB). This was tested by applying electrical field stimulation in the dorsal part of the MOB while recording large principal cells (LPCs) of the anterior AOB (aAOB). Additional recordings of LPCs were performed at either side of the plane of intersection between the aAOB and posterior-AOB (pAOB) halves, or linea alba, while applying field stimulation to the opposite half. A total of 92 recorded neurons were filled during whole-cell recordings with biocytin and studied at the light microscope. Neurons located in the aAOB (n = 6, 8%) send axon collaterals to the MOB since they were antidromically activated in the presence of glutamate receptor antagonists (APV and CNQX). Recorded LPCs evoked orthodromic excitatory post-synaptic responses (n = 6, aAOB; n = 1, pAOB) or antidromic action potentials (n = 8, aAOB; n = 7, pAOB) when applying field stimulation to the opposite half of the recording site (e.g., recording in aAOB; stimulating in pAOB, and vice-versa). Observation of the filled neurons revealed that indeed, LPCs send axon branches that cross the linea alba to resolve in the internal cellular layer. Additionally, LPCs of the aAOB send axon collaterals to dorsal-MOB territory. Notably, while performing AOB recordings we found a sub-population of neurons (24% of the total) that exhibited voltage-dependent bursts of action potentials. Our findings support the existence of: 1. a direct projection from aAOB LPCs to dorsal-MOB, 2. physiologically active synapses linking aAOB and pAOB, and 3. pacemaker-like neurons in both AOB halves. This work was presented in the form of an Abstract on SfN 2014 (719.14/EE17). PMID:26858596

  15. 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. PMID:26582499

  16. A TAP1 null mutation leads to an enlarged olfactory bulb and supernumerary, ectopic olfactory glomeruli

    PubMed Central

    Salcedo, Ernesto; Cruz, Nicole M.; Ly, Xuan; Welander, Beth A.; Hanson, Kyle; Kronberg, Eugene; Restrepo, Diego

    2013-01-01

    Major histocompatibility class I (MHCI) molecules are well known for their immunological role in mediating tissue graft rejection. Recently, these molecules were discovered to be expressed in distinct neuronal subclasses, dispelling the long-held tenet that the uninjured brain is immune-privileged. Here, we show that MHCI molecules are expressed in the main olfactory bulb (MOB) of adult animals. Furthermore, we find that mice with diminished levels of MHCI expression have enlarged MOBs containing an increased number of small, morphologically abnormal and ectopically located P2 glomeruli. These findings suggest that MHCI molecules may play an important role in the proper formation of glomeruli in the bulb. PMID:23697805

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

    PubMed

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

    2015-10-01

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

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

    PubMed Central

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

    2015-01-01

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

  19. Developmental, tract-tracing and immunohistochemical study of the peripheral olfactory system in a basal vertebrate: insights on Pax6 neurons migrating along the olfactory nerve.

    PubMed

    Quintana-Urzainqui, Idoia; Rodríguez-Moldes, Isabel; Candal, Eva

    2014-01-01

    The olfactory system represents an excellent model for studying different aspects of the development of the nervous system ranging from neurogenesis to mechanisms of axon growth and guidance. Important findings in this field come from comparative studies. We have analyzed key events in the development of the olfactory system of the shark Scyliorhinus canicula by combining immunohistochemical and tract-tracing methods. We describe for the first time in a cartilaginous fish an early population of pioneer HuC/D-immunoreactive (ir) neurons that seemed to delaminate from the olfactory pit epithelium and migrate toward the telencephalon before the olfactory nerve was identifiable. A distinct, transient cell population, namely the migratory mass, courses later on in apposition to the developing olfactory nerve. It contains olfactory ensheathing glial (GFAP-ir) cells and HuC/D-ir neurons, some of which course toward an extrabulbar region. We also demonstrate that Pax6-ir cells coursing along the developing olfactory pathways in S. canicula are young migrating (HuC/D and DCX-ir) neurons of the migratory mass that do not form part of the terminal nerve pathway. Evidences that these Pax6 neurons originate in the olfactory epithelium are also reported. As Pax6 neurons in the olfactory epithelium show characteristics of olfactory receptor neurons, and migrating Pax6-ir neurons formed transient corridors along the course of olfactory axons at the entrance of the olfactory bulb, we propose that these neurons could play a role as guideposts for axons of olfactory receptor neurons growing toward the olfactory bulb. PMID:23224251

  20. Expression of Olfactory Signaling Genes in the Eye

    PubMed Central

    Velmeshev, Dmitry; Faghihi, Mohammad; Shestopalov, Valery I.; Slepak, Vladlen Z.

    2014-01-01

    Purpose To advance our understanding how the outer eye interacts with its environment, we asked which cellular receptors are expressed in the cornea, focusing on G protein-coupled receptors. Methods Total RNA from the mouse cornea was subjected to next-generation sequencing using the Illumina platform. The data was analyzed with TopHat and CuffLinks software packages. Expression of a representative group of genes detected by RNA-seq was further analyzed by RT-PCR and in situ hybridization using RNAscope technology and fluorescent microscopy. Results We generated more than 46 million pair-end reads from mouse corneal RNA. Bioinformatics analysis revealed that the mouse corneal transcriptome reconstructed from these reads represents over 10,000 gene transcripts. We identified 194 GPCR transcripts, of which 96 were putative olfactory receptors. RT-PCR analysis confirmed the presence of several olfactory receptors and related genes, including olfactory marker protein and the G protein associated with olfaction, Gαolf. In situ hybridization showed that mRNA for olfactory marker protein, Gαolf and possibly some olfactory receptors were found in the corneal epithelial cells. In addition to the corneal epithelium, Gαolf was present in the ganglionic and inner nuclear layers of the retina. One of the olfactory receptors, Olfr558, was present primarily in vessels of the eye co-stained with antibodies against alpha-smooth muscle actin, indicating expression in arterioles. Conclusions Several species of mRNA encoding putative olfactory receptors and related genes are expressed in the mouse cornea and other parts of the eye indicating they may play a role in sensing chemicals in the ocular environment. PMID:24789354

  1. Using insect electroantennogram sensors on autonomous robots for olfactory searches.

    PubMed

    Martinez, Dominique; Arhidi, Lotfi; Demondion, Elodie; Masson, Jean-Baptiste; Lucas, Philippe

    2014-01-01

    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. PMID:25145980

  2. 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

  3. 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

  4. Functional representation of olfactory impairment in early Alzheimer's disease.

    PubMed

    Förster, Stefan; Vaitl, Andreas; Teipel, Stefan J; Yakushev, Igor; Mustafa, Mona; la Fougère, Christian; Rominger, Axel; Cumming, Paul; Bartenstein, Peter; Hampel, Harald; Hummel, Thomas; Buerger, Katharina; Hundt, Walter; Steinbach, Silke

    2010-01-01

    We used [18F]fluorodeoxyglucose (FDG) PET analysis to determine performance in different olfactory domains of patients with early AD compared to cognitively healthy subjects, and to map the functional metabolic representation of olfactory impairment in the patient sample. A cohort of patients with early AD (n=24), consisting of 6 subjects with incipient AD and 18 subjects with mild AD, and a control group of 28 age-matched non-demented individuals were assembled. Patients and controls were tested for olfactory performance using the "Sniffin' Sticks" test battery [odor identification (ID), discrimination (DIS) and threshold (THR)], while patients additionally underwent resting state FDG-PET. Voxel-wise PET results in the patients were correlated with olfaction scores using the general linear model in SPM5. Patients with early AD showed significantly reduced function in all three olfactory subdomains compared to controls. After controlling for effects due to patients' age, gender, cognitive status, and treating scores in the two other olfactory subdomains as nuisance variables, ID scores correlated with normalized FDG uptake in clusters with peaks in the right superior parietal lobule, fusiform gyrus, inferior frontal gyrus, and precuneus, while DIS scores correlated with a single cluster in the left postcentral cortex, and THR scores correlated with clusters in the right thalamus and cerebellum. The subtests employed in the "Sniffin' Sticks" test battery are complementary indicators of different aspects of olfactory dysfunction in early AD, and support the theory of a parallel organized olfactory system, revealed by FDG-PET correlation analysis. PMID:20847402

  5. Neural representations of novel objects associated with olfactory experience.

    PubMed

    Ghio, Marta; Schulze, Patrick; Suchan, Boris; Bellebaum, Christian

    2016-07-15

    Object conceptual knowledge comprises information related to several motor and sensory modalities (e.g. for tools, how they look like, how to manipulate them). Whether and to which extent conceptual object knowledge is represented in the same sensory and motor systems recruited during object-specific learning experience is still a controversial question. A direct approach to assess the experience-dependence of conceptual object representations is based on training with novel objects. The present study extended previous research, which focused mainly on the role of manipulation experience for tool-like stimuli, by considering sensory experience only. Specifically, we examined the impact of experience in the non-dominant olfactory modality on the neural representation of novel objects. Sixteen healthy participants visually explored a set of novel objects during the training phase while for each object an odor (e.g., peppermint) was presented (olfactory-visual training). As control conditions, a second set of objects was only visually explored (visual-only training), and a third set was not part of the training. In a post-training fMRI session, participants performed an old/new task with pictures of objects associated with olfactory-visual and visual-only training (old) and no training objects (new). Although we did not find any evidence of activations in primary olfactory areas, the processing of olfactory-visual versus visual-only training objects elicited greater activation in the right anterior hippocampus, a region included in the extended olfactory network. This finding is discussed in terms of different functional roles of the hippocampus in olfactory processes. PMID:27083305

  6. Molecular Dynamics Simulations of Water/Mucus Partition Coefficients for Feeding Stimulants in Fish and the Implications for Olfaction

    PubMed Central

    Rygg, Alex D.; van Duin, Adri C. T.; Craven, Brent A.

    2013-01-01

    The odorant partition coefficient is a physicochemical property that has been shown to dramatically influence odorant deposition patterns in the mammalian nose, leading to a chromatographic separation of odorants along the sensory epithelium. It is unknown whether a similar phenomenon occurs in fish. Here we utilize molecular dynamics simulations, based on a simplified molecular model of olfactory mucus, to calculate water/mucus partition coefficients for amino acid odorants (alanine, glycine, cysteine, and valine) that are known to elicit feeding behavior in fish. Both fresh water and salt water environments are considered. In fresh water, all four amino acids prefer the olfactory mucus phase to water, and the partition coefficient is shown to correlate with amino acid hydrophobicity. In salt water, a reversal in odorant partitioning is found, where each of the feeding stimulants (except glycine) prefer the water phase to olfactory mucus. This is due to the interactions between the salt ions and the odorant molecules (in the water phase), and between the salt and simplified mucin (in the olfactory mucus phase). Thus, slightly different odorant deposition patterns may occur in the fish olfactory organ in fresh and salt water environments. However, in both underwater environments we found that the variation of the water/mucus odorant partition coefficient is approximately one order of magnitude, in stark contrast to air/mucus odorant partition coefficients that can span up to six orders of magnitude. We therefore anticipate relatively similar deposition patterns for most amino acid odorants in the fish olfactory chamber. Thus, in contrast to terrestrial species, living in an underwater environment may preclude appreciable chromatographic odorant separation that may be used for spatial coding of odor identity across the olfactory epithelium. This is consistent with the reported lack of spatial organization of olfactory receptor neurons in the fish olfactory

  7. 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.

  8. Pheromone discrimination ability of olfactory bulb mitral and ruffed cells in the goldfish (Carassius auratus).

    PubMed

    Zippel, H P; Gloger, M; Lüthje, L; Nasser, S; Wilcke, S

    2000-06-01

    Significant anatomical differences characterizing mitral cells and ruffed cells were published by Kosaka and Hama in three teleost species. Physiological responses from both types of relay neurons have now been recorded extracellularly and simultaneously in the plexiform layer using a single tungsten microelectrode. During interstimulus intervals mitral cells responded with higher, frequently burst-like impulse rates triggered by the activity of epithelial receptor neurons. Ruffed cell impulse rates were low, and each action potential triggered a long-lasting, continuously variable, integrated granule cell potential. During olfactory stimulation with important biological stimuli such as preovulatory and ovulatory pheromones, a probable alarm pheromone and amino acids contrasting interactions between mitral cells and ruffed cells resulting in a drastic intensification of centrally transmitted information were frequently recorded. Individual neurons excellently discriminated stimuli. Irrespective of the physiological relevance of stimuli, however, similarities were recorded in the distribution of excitatory, inhibitory and indifferent responses. PMID:10866992

  9. 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. PMID:27395410

  10. Spike encoding of olfactory receptor cells.

    PubMed

    Narusuye, Kenji; Kawai, Fusao; Miyachi, Ei-ichi

    2003-08-01

    Olfaction begins with the transduction of the information carried by odorants into electrical signals in olfactory receptor cells (ORCs). The binding of odor molecules to specific receptor proteins on the ciliary surface of ORCs induces the receptor potentials. This initial excitation causes a slow and graded depolarizing voltage change, which is encoded into a train of action potentials. Action potentials of ORCs are generated by voltage-gated Na+ currents and T-type Ca2+ currents in the somatic membrane. Isolated ORCs, which have lost their cilia during the dissociation procedure, are known to exhibit spike frequency accommodation by injecting the steady current. This raises the possibility that somatic ionic channels in ORCs may serve for odor adaptation at the level of spike encoding, although odor adaptation is mainly accomplished by the ciliary transduction machinery. This review discusses current knowledge concerning the mechanisms of spike generation in ORCs. It also reviews how neurotransmitters and hormones modulate ionic currents and action potentials in ORCs. PMID:12871762

  11. A world without the olfactory dimension.

    PubMed

    Tafalla, Marta

    2013-09-01

    This article aims to describe what is it like to perceive reality when suffering from congenital anosmia. Nevertheless, this objective entails a fundamental difficulty. Since I have never had the experience of olfaction, it seems natural to me to live in a world lacking the olfactory dimension; this subjective perception is the only one I know and in consequence it is difficult to describe. For this reason, in recent years I have begun to develop long conversations with other people suffering from congenital anosmia, people who have lost their sense of olfaction in adulthood and also people with a good sense of smell. My goal is to draw a map showing the principal differences that might allow us to develop a systematic comparison. Obviously, this is not an experimental or quantitative scientific procedure, but only a modest attempt to compare personal stories about subjective experiences. It is a philosophical-literary exercise, and does not aim to be anything other than that. But I hope it will help to formulate meaningful questions, which would then need a properly scientific approach. In the first part of this article I want to try to describe how I became aware that other people could smell; and in a second part, I will try to examine the consequences of anosmia in different areas of everyday life: nourishment, relationships with people, own body perception, natural or urban environments perception, time perception, and finally aesthetic appreciation and the implications of living in a world without stench. PMID:23907763

  12. Olfactory assessment using the NIH Toolbox.

    PubMed

    Dalton, Pamela; Doty, Richard L; Murphy, Claire; Frank, Robert; Hoffman, Howard J; Maute, Christopher; Kallen, Michael A; Slotkin, Jerry

    2013-03-12

    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

  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. 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. PACAP protects against TNFα-induced cell death in olfactory epithelium and olfactory placodal cell lines

    PubMed Central

    Kanekar, Shami; Gandham, Mahendra; Lucero, Mary T

    2010-01-01

    In mouse olfactory epithelium (OE), pituitary adenylate cyclase activating peptide (PACAP) protects against axotomy-induced apoptosis. We used mouse OE to determine whether PACAP protects neurons during exposure to the inflammatory cytokine TNFα. Live slices of neonatal mouse OE were treated with 40 ng/ml TNFα ± 40 nM PACAP for 6 hours and dying cells were live-labeled with 0.5% propidium iodide. TNFα significantly increased the percentage of dying cells while co-incubation with PACAP prevented cell death. PACAP also prevented TNFα-mediated cell death in the olfactory placodal (OP) cell lines, OP6 and OP27. Although OP cell lines express all three PACAP receptors (PAC1, VPAC1,VPAC2), PACAP’s protection of these cells from TNFα was mimicked by the specific PAC1 receptor agonist maxadilan and abolished by the PAC1 antagonist PACAP6–38. Treatment of OP cell lines with blockers or activators of the PLC and AC/MAPKK pathways revealed that PACAP-mediated protection from TNFα involved both pathways. PACAP may therefore function through PAC1 receptors to protect neurons from cell death during inflammatory cytokine release in vivo as would occur upon viral infection or allergic rhinitis-associated injury. PMID:20654718

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

    PubMed Central

    Fletcher, Max L.

    2012-01-01

    The anatomical organization of receptor neuron input into the olfactory bulb (OB) allows odor information to be transformed into an odorant-specific spatial map of mitral/tufted (M/T) cell glomerular activity at the upper level of the OB. In other sensory systems, neuronal representations of stimuli can be reorganized or enhanced following learning. While the mammalian OB has been shown to undergo experience-dependent plasticity at the glomerular level, it is still unclear if similar representational change occurs within (M/T) cell glomerular odor representations following learning. To address this, odorant-evoked glomerular activity patterns were imaged in mice expressing a GFP-based calcium indicator (GCaMP2) in OB (M/T) cells. Glomerular odor responses were imaged before and after olfactory associative conditioning to aversive foot shock. Following conditioning, we found no overall reorganization of the glomerular representation. Training, however, did significantly alter the amplitudes of individual glomeruli within the representation in mice in which the odor was presented together with foot shock. Further, the specific pairing of foot shock with odor presentations lead to increased responses primarily in initially weakly activated glomeruli. Overall, these results suggest that associative conditioning can enhance the initial representation of odors within the OB by enhancing responses to the learned odor in some glomeruli. PMID:22461771

  17. 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

  18. Differential Contributions of Olfactory Receptor Neurons in a Drosophila Olfactory Circuit.

    PubMed

    Newquist, Gunnar; Novenschi, Alexandra; Kohler, Donovan; Mathew, Dennis

    2016-01-01

    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

  19. 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

  20. 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

  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. From chemical neuroanatomy to an understanding of the olfactory system

    PubMed Central

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

    2011-01-01

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

  3. Assessing olfactory performance in an Old World primate, Macaca nemestrina.

    PubMed

    Hübener, F; Laska, M

    1998-06-15

    The present study demonstrates that an operant conditioning paradigm, originally designed for assessing olfactory performance in a small New World primate, the squirrel monkey, can successfully be adapted for use with a large Old World primate, the pigtail macaque. Using a task designed to simulate olfactory-guided foraging behavior, based on multiple discrimination of simultaneously presented odor stimuli, we could show that Macaca nemestrina is able to learn to discriminate between objects on the basis of odor cues. Moreover, they could readily transfer to new S+ and S- stimuli and could remember the significance of previously learned odor stimuli even after a 3-week break. Furthermore, we could show that this method is suitable for obtaining reliable measures of olfactory sensitivity. The few modifications of the original method employed here did not affect essential features such as the mode of stimulus presentation (odorized paper strips attached to manipulation objects) and the choice criterion (opening or rejecting the odorized manipulation objects), thus for the first time enabling valid interspecific comparisons of olfactory capabilities between a catarrhine and a platyrrhine primate species. Our results indicate that M. nemestrina and Saimiri sciureus are similar with regard to several measures of olfactory performance, such as speed of initial task acquisition and ability to master transfer tasks as well as their sensitivity to a food-related odorant. PMID:9761227

  4. 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

  5. Olfactory insights into sleep-dependent learning and memory.

    PubMed

    Shanahan, Laura K; Gottfried, Jay A

    2014-01-01

    Sleep is pervasive throughout most of the animal kingdom-even jellyfish and honeybees do it. Although the precise function of sleep remains elusive, research increasingly suggests that sleep plays a key role in memory consolidation. Newly formed memories are highly labile and susceptible to interference, and the sleep period offers an optimal window in which memories can be strengthened or modified. Interestingly, a small but growing research area has begun to explore the ability of odors to modulate memories during sleep. The unique anatomical organization of the olfactory system, including its intimate overlap with limbic systems mediating emotion and memory, and the lack of a requisite thalamic intermediary between the nasal periphery and olfactory cortex, suggests that odors may have privileged access to the brain during sleep. Indeed, it has become clear that the long-held assumption that odors have no impact on the sleeping brain is no longer tenable. Here, we summarize recent studies in both animal and human models showing that odor stimuli experienced in the waking state modulate olfactory cortical responses in sleep-like states, that delivery of odor contextual cues during sleep can enhance declarative memory and extinguish fear memory, and that olfactory associative learning can even be achieved entirely within sleep. Data reviewed here spotlight the emergence of a new research area that should hold far-reaching implications for future neuroscientific investigations of sleep, learning and memory, and olfactory system function. PMID:24767488

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

    PubMed

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

    2011-01-01

    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. PMID:22297441

  7. Disruption of Olfactory Receptor Neuron Patterning in Scutoid mutant Drosophila

    PubMed Central

    Tom, W.; de Bruyne, M.; Haehnel, M.; Carlson, J. R.; Ray, A.

    2010-01-01

    Olfactory neurons show an extreme diversity of cell types with each cell usually expressing one member from a large family of 60 Odorant receptor (Or)genes in Drosophila. Little is known about the developmental processes and transcription factors that generate this stereotyped pattern of cellular diversity. Here we investigate the molecular and cellular basis of defects in olfactory system function in an unusual dominant mutant, Scutoid. We show that the defects map to olfactory neurons innervating a specific morphological class of sensilla on the antenna, large basiconics. Molecular analysis indicates defects in neurons expressing specific classes of receptor genes that map to large basiconic sensilla. Previous studies have shown that in Scutoid mutants the coding region of the transcriptional repressor snail is translocated near the no-ocelli promoter, leading to misexpression of snail in the developing eye-antenna disc. We show that ectopic expression of snail in developing olfactory neurons leads to severe defects in neurons of the antennal large basiconics supporting the model that the dominant olfactory phenotype in Scutoid is caused by misexpression of snail. PMID:20875862

  8. Properties and mechanisms of olfactory learning and memory

    PubMed Central

    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. PMID:25071492

  9. 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.

  10. Predicting olfactory receptor neuron responses from odorant structure

    PubMed Central

    Schmuker, Michael; de Bruyne, Marien; Hähnel, Melanie; Schneider, Gisbert

    2007-01-01

    Background Olfactory receptors work at the interface between the chemical world of volatile molecules and the perception of scent in the brain. Their main purpose is to translate chemical space into information that can be processed by neural circuits. Assuming that these receptors have evolved to cope with this task, the analysis of their coding strategy promises to yield valuable insight in how to encode chemical information in an efficient way. Results We mimicked olfactory coding by modeling responses of primary olfactory neurons to small molecules using a large set of physicochemical molecular descriptors and artificial neural networks. We then tested these models by recording in vivo receptor neuron responses to a new set of odorants and successfully predicted the responses of five out of seven receptor neurons. Correlation coefficients ranged from 0.66 to 0.85, demonstrating the applicability of our approach for the analysis of olfactory receptor activation data. The molecular descriptors that are best-suited for response prediction vary for different receptor neurons, implying that each receptor neuron detects a different aspect of chemical space. Finally, we demonstrate that receptor responses themselves can be used as descriptors in a predictive model of neuron activation. Conclusion The chemical meaning of molecular descriptors helps understand structure-response relationships for olfactory receptors and their "receptive fields". Moreover, it is possible to predict receptor neuron activation from chemical structure using machine-learning techniques, although this is still complicated by a lack of training data. PMID:17880742

  11. 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

  12. 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

  13. Olfactory functioning in early multiple sclerosis: Sniffin’ Sticks Test study

    PubMed Central

    Batur Caglayan, Hale Z; Irkec, Ceyla; Nazliel, Bijen; Akyol Gurses, Aslı; Capraz, Irem

    2016-01-01

    Introduction Previous studies have shown that olfactory functioning is affected by multiple sclerosis (MS). This study assessed the level of the olfactory impairment in early MS by using the Sniffin’ Sticks Test. Methods This study included 30 patients with MS and 30 healthy controls. We collected demographic and clinical data from participants and administered the Sniffin’ Sticks Test. Results We found no differences between the MS and control groups in odor discrimination, odor identification, and threshold discrimination identification scores, but odor threshold (OT) scores were higher in the control group than in the MS group (P=0.49). In addition, we did not find any correlation between MS patients’ olfactory test scores and their scores on the Mini–Mental State Examination (MMSE), Expanded Disability Status Scale (EDSS), disease duration, history of optic neuritis, or being on immunomodulatory therapy. Conclusion In recent studies, odor threshold impairment seemed to be the most striking finding in patients with MS. Although the present study found a mild alteration in odor threshold, olfactory dysfunction appears to be a consequence of neurodegeneration in the higher order olfactory brain regions, which is thought to be a time-dependent process. PMID:27621629

  14. Interactions of carbon dioxide and food odours in Drosophila: olfactory hedonics and sensory neuron properties.

    PubMed

    Faucher, Cécile P; Hilker, Monika; de Bruyne, Marien

    2013-01-01

    Behavioural responses of animals to volatiles in their environment are generally dependent on context. Most natural odours are mixtures of components that can each induce different behaviours when presented on their own. We have investigated how a complex of two olfactory stimuli is evaluated by Drosophila flies in a free-flying two-trap choice assay and how these stimuli are encoded in olfactory receptor neurons. We first observed that volatiles from apple cider vinegar attracted flies while carbon dioxide (CO2) was avoided, confirming their inherent positive and negative values. In contradiction with previous results obtained from walking flies in a four-field olfactometer, in the present assay the addition of CO2 to vinegar increased rather than decreased the attractiveness of vinegar. This effect was female-specific even though males and females responded similarly to CO2 and vinegar on their own. To test whether the female-specific behavioural response to the mixture correlated with a sexual dimorphism at the peripheral level we recorded from olfactory receptor neurons stimulated with vinegar, CO2 and their combination. Responses to vinegar were obtained from three neuron classes, two of them housed with the CO2-responsive neuron in ab1 sensilla. Sensitivity of these neurons to both CO2 and vinegar per se did not differ between males and females and responses from female neurons did not change when CO2 and vinegar were presented simultaneously. We also found that CO2-sensitive neurons are particularly well adapted to respond rapidly to small concentration changes irrespective of background CO2 levels. The ability to encode temporal properties of stimulations differs considerably between CO2- and vinegar-sensitive neurons. These properties may have important implications for in-flight navigation when rapid responses to fragmented odour plumes are crucial to locate odour sources. However, the flies' sex-specific response to the CO2-vinegar combination and the

  15. Blood supply of the olfactory nerve. Meningeal relationships and surgical relevance.

    PubMed

    Favre, J J; Chaffanjon, P; Passagia, J G; Chirossel, J P

    1995-01-01

    The authors report the results of a series of dissections and anatomic sections of the fronto-basal region of the brain and of the anterior cranial fossa in human cadavers. The constant presence of an arachnoidal cistern above the olfactory nerve was verified. The arachnoid separates from the pial membrane and forms a bridge with the ventral part of the olfactory bulb and tract, from the lateral edge of the olfactory sulcus to the medial edge of the gyrus rectus. The cistern is wide in its anterior portion, between the gyrus rectus and the olfactory bulb, and is reduced to a virtual slit in its posterior portion where the tract is lodged in the olfactory sulcus. The olfactory nerve can be separated without damaging fronto-basal arachnoidial adhesions over several centimeters. Dissection of this region after intravascular injection of colored media shows the constant presence of an artery destined to the olfactory bulb and tract. It originates either from the lateral surface of the anterior cerebral a. (segment A2), or from the medial fronto-basal a., and consistently provides terminal branches in front of the olfactory trigone in the medial olfactory sulcus. At their ventral extremity, the olfactory structures are therefore vascularised independently for several centimeters, from the lower face of the frontal lobe. The independent vascularisation of the olfactory nerve, the tenuous and easily detachable adhesions, and the actual presence of a true arachnoidal cistern all contribute to enabling surgical techniques which conserve olfactory function during anterior approaches. PMID:7482150

  16. Anosmin-1a is required for fasciculation and terminal targeting of olfactory sensory neuron axons in the zebrafish olfactory system.

    PubMed

    Yanicostas, Constantin; Herbomel, Eric; Dipietromaria, Aurélie; Soussi-Yanicostas, Nadia

    2009-11-27

    The KAL-1 gene underlies the X-linked form of Kallmann syndrome (KS), a neurological disorder that impairs the development of the olfactory and GnRH systems. KAL-1 encodes anosmin-1, a cell matrix protein that shows cell adhesion, neurite outgrowth, and axon-guidance and -branching activities. We used zebrafish embryos as model to better understand the role of this protein during olfactory system (OS) development. First, we detected the protein in olfactory sensory neurons from 22 h post-fertilization (hpf) onward, i.e. prior their pioneer axons reached presumptive olfactory bulbs (OBs). We found that anosmin-1a depletion impaired the fasciculation of olfactory axons and their terminal targeting within OBs. Last, we showed that kal1a inactivation induced a severe decrease in the number of GABAergic and dopaminergic OB neurons. Though the phenotypes induced following anosmin-1a depletion in zebrafish embryos did not match precisely the defects observed in KS patients, our results provide the first demonstration of a direct requirement for anosmin-1 in OS development in vertebrates and stress the role of OB innervation on OB neuron differentiation. PMID:19464344

  17. Inhibition of Olfactory Receptor Neuron Input to Olfactory Bulb Glomeruli Mediated by Suppression of Presynaptic Calcium Influx

    PubMed Central

    Wachowiak, Matt; McGann, John P.; Heyward, Philip M.; Shao, Zuoyi; Puche, Adam C.; Shipley, Michael T.

    2005-01-01

    We investigated the cellular mechanism underlying presynaptic regulation of olfactory receptor neuron (ORN) input to the mouse olfactory bulb using optical-imaging techniques that selectively report activity in the ORN pre-synaptic terminal. First, we loaded ORNs with calcium-sensitive dye and imaged stimulus-evoked calcium influx in a slice preparation. Single olfactory nerve shocks evoked rapid fluorescence increases that were largely blocked by the N-type calcium channel blocker ω-conotoxin GVIA. Paired shocks revealed a long-lasting suppression of calcium influx with ~40% suppression at 400-ms interstimulus intervals and a recovery time constant of ~450 ms. Blocking activation of postsynaptic olfactory bulb neurons with APV/CNQX reduced this suppression. The GABAB receptor agonist baclofen inhibited calcium influx, whereas GABAB antagonists reduced paired-pulse suppression without affecting the response to the conditioning pulse. We also imaged transmitter release directly using a mouse line that expresses synaptopHluorin selectively in ORNs. We found that the relationship between calcium influx and transmitter release was superlinear and that paired-pulse suppression of transmitter release was reduced, but not eliminated, by APV/CNQX and GABAB antagonists. These results demonstrate that primary olfactory input to the CNS can be presynaptically regulated by GABAergic interneurons and show that one major intracellular pathway for this regulation is via the suppression of calcium influx through N-type calcium channels in the pre-synaptic terminal. This mechanism is unique among primary sensory afferents. PMID:15917320

  18. Decoding of Context-Dependent Olfactory Behavior in Drosophila.

    PubMed

    Badel, Laurent; Ohta, Kazumi; Tsuchimoto, Yoshiko; Kazama, Hokto

    2016-07-01

    Odor information is encoded in the activity of a population of glomeruli in the primary olfactory center. However, how this information is decoded in the brain remains elusive. Here, we address this question in Drosophila by combining neuronal imaging and tracking of innate behavioral responses. We find that the behavior is accurately predicted by a model summing normalized glomerular responses, in which each glomerulus contributes a specific, small amount to odor preference. This model is further supported by targeted manipulations of glomerular input, which biased the behavior. Additionally, we observe that relative odor preference changes and can even switch depending on the context, an effect correctly predicted by our normalization model. Our results indicate that olfactory information is decoded from the pooled activity of a glomerular repertoire and demonstrate the ability of the olfactory system to adapt to the statistics of its environment. PMID:27321924

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

    PubMed

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

    2013-12-01

    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. PMID:24239124

  20. Illustrated Review of the Ventral Striatum's Olfactory Tubercle.

    PubMed

    Xiong, Angeline; Wesson, Daniel W

    2016-09-01

    Modern neuroscience often relies upon artistic renderings to illustrate key aspects of anatomy. These renderings can be in 2 or even 3 dimensions. Three-dimensional renderings are especially helpful in conceptualizing highly complex aspects of neuroanatomy which otherwise are not visually apparent in 2 dimensions or even intact biological samples themselves. Here, we provide 3 dimensional renderings of the gross- and cellular-anatomy of the rodent olfactory tubercle. Based upon standing literature and detailed investigations into rat brain specimens, we created biologically inspired illustrations of the olfactory tubercle in 3 dimensions as well as its connectivity with olfactory bulb projection neurons, the piriform cortex association fiber system, and ventral pallidum medium spiny neurons. Together, we intend for these illustrations to serve as a resource to the neuroscience community in conceptualizing and discussing this highly complex and interconnected brain system with established roles in sensory processing and motivated behaviors. PMID:27340137

  1. Early Olfactory Processing in Drosophila: Mechanisms and Principles

    PubMed Central

    Wilson, Rachel I.

    2014-01-01

    In the olfactory system of Drosophila melanogaster, it is relatively straightforward to make in vivo measurements of activity in neurons corresponding to targeted processing. This, together with the numerical simplicity of the Drosophila olfactory system, has produced rapid gains in our understanding of Drosophila olfaction. This review summarizes the neurophysiology of the first two layers of this system: the peripheral olfactory receptor neurons and their postsynaptic targets in the antennal lobe. We now understand in some detail the cellular and synaptic mechanisms that shape odor representations in these neurons. Together, these mechanisms imply that interesting neural adaptations to environmental statistics have occurred and place some fundamental constraints on early sensory processing that pose challenges for higher brain regions. These findings suggest some general principles with broad relevance to early sensory processing in other modalities. PMID:23841839

  2. Beyond the olfactory bulb: An odotopic map in the forebrain

    PubMed Central

    Nikonov, Alexander A.; Finger, Thomas E.; Caprio, John

    2005-01-01

    We report electrophysiological evidence that a simple odotopy, the spatial mapping of different odorants, is maintained above the level of the olfactory bulb (OB). Three classes of biologically relevant odorants for fish are processed in distinct regions of the forebrain (FB) in the channel catfish. Feeding cues, mainly amino acids and nucleotides, are represented in lateral, pallial portions of the FB, equivalent to the olfactory cortex of amniote vertebrates, whereas social signals mediated by bile salts are represented in medial FB centers, possibly homologous to portions of the amygdala. As in the OB, the different odorant classes map onto different territories; however, the response properties of units of the olfactory areas of the FB do not simply mirror those of the OB. For some units, distinctive response properties emerged, because the FB is the first center where odors subserving a common behavioral function (i.e., food function) converge. PMID:16339016

  3. Presynaptic gamma-aminobutyric acid responses in the olfactory cortex.

    PubMed Central

    Pickles, H G

    1979-01-01

    1. Potential changes were recorded from the lateral olfactory tract in slices of rat olfactory cortex in vitro at room temperature. 2. Superfused gamma-aminobutyric acid (GABA) usually produced dose-related depolarization of the lateral olfactory tract. Muscimol and 3-aminopropanesulphonic acid appeared more potent depolarizing agents than GABA, and glycine and taurine appeared less potent. Carbachol and glutamate were virtually ineffective. 3. The GABA responses were at least partially Cl- dependent. 4. (+)-Bicuculline and higher concentrations of strychnine antagonized the GABA but not the glycine-induced depolarizations. Paradoxically, responses to high doses of GABA were sometimes potentiated by both bicuculline and strychnine. 5. It is suggested that GABA receptors could occur as widely on nerve terminals as they do postsynaptically in the CNS, where GABA could be involved in the modulation of transmitter output. PMID:760898

  4. Olfactory disorders and quality of life--an updated review.

    PubMed

    Croy, Ilona; Nordin, Steven; Hummel, Thomas

    2014-03-01

    Olfactory disorders are common and affect about one-fifth of the general population. The main causes of olfactory loss are post viral upper respiratory infection, nasal/sinus disease, and head trauma and are therefore very frequent among patients in ear, nose, and throat clinics. We have systematically reviewed the impact of quantitative, qualitative, and congenital olfactory disorders on daily life domains as well as on general quality of life and depression. From the extensive body of literature, it can be concluded that loss of the sense of smell leads to disturbances in important areas, mainly in food enjoyment, detecting harmful food and smoke, and to some extent in social situations and working life. Most patients seem to deal well and manage those restrictions. However, a smaller proportion has considerable problems and expresses a noticeable reduction in general quality of life and enhanced depression. The impact of coping strategies is discussed. PMID:24429163

  5. Evidence for a Peripheral Olfactory Memory in Imprinted Salmon

    NASA Astrophysics Data System (ADS)

    Nevitt, Gabrielle A.; Dittman, Andrew H.; Quinn, Thomas P.; Moody, William J., Jr.

    1994-05-01

    The remarkable homing ability of salmon relies on olfactory cues, but its cellular basis is unknown. To test the role of peripheral olfactory receptors in odorant memory retention, we imprinted coho salmon (Oncorhynchus kisutch) to micromolar concentrations of phenyl ethyl alcohol during parr-smolt transformation. The following year, we measured phenyl ethyl alcohol responses in the peripheral receptor cells using patch clamp. Cells from imprinted fish showed increased sensitivity to phenyl ethyl alcohol compared either to cells from naive fish or to sensitivity to another behaviorally important odorant (L-serine). Field experiments verified an increased behavioral preference for phenyl ethyl alcohol by imprinted salmon as adults. Thus, some component of the imprinted olfactory homestream memory appears to be retained peripherally.

  6. 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. PMID:25447513

  7. 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

  8. Of mice and men: olfactory neuroblastoma among animals and humans.

    PubMed

    Lubojemska, A; Borejko, M; Czapiewski, P; Dziadziuszko, R; Biernat, W

    2016-09-01

    Olfactory neuroblastoma (ONB) is a rare tumour of nasal cavity and paranasal sinuses that arises from the olfactory neuroepithelium and has unpredictable clinical course. As the sense of smell is phylogenetically one of the first senses and olfactory neuroepithelium is evolutionary conserved with striking similarities among different species, we performed an extensive analysis of the literature in order to evaluate the similarities and differences between animals and humans on the clinical, morphological, immunohistochemical, ultrastructural and molecular level. Our analysis revealed that ONB was reported mainly in mammals and showed striking similarities to human ONB. These observations provide rationale for introduction of therapy modalities used in humans into the veterinary medicine. Animal models of neuroblastoma should be considered for the preclinical studies evaluating novel therapies for ONB. PMID:25041470

  9. Effect of Flumethrin on Survival and Olfactory Learning in Honeybees

    PubMed Central

    Tan, Ken; Yang, Shuang; Wang, Zhengwei; Menzel, Randolf

    2013-01-01

    Flumethrin has been widely used as an acaricide for the control of Varroa mites in commercial honeybee keeping throughout the world for many years. Here we test the mortality of the Asian honeybee Apis cerana cerana after treatment with flumethrin. We also ask (1) how bees react to the odor of flumethrin, (2) whether its odor induces an innate avoidance response, (3) whether its taste transmits an aversive reinforcing component in olfactory learning, and (4) whether its odor or taste can be associated with reward in classical conditioning. Our results show that flumethrin has a negative effect on Apis ceranàs lifespan, induces an innate avoidance response, acts as a punishing reinforcer in olfactory learning, and interferes with the association of an appetitive conditioned stimulus. Furthermore flumethrin uptake within the colony reduces olfactory learning over an extended period of time. PMID:23785490

  10. Effect of putative pheromones on the electrical activity of the human vomeronasal organ and olfactory epithelium.

    PubMed

    Monti-Bloch, L; Grosser, B I

    1991-10-01

    The summated receptor potential was recorded from the vomeronasal organ (VNO) and olfactory epithelium (OE) of 49 human subjects of both sexes (18 to 55 years old) using surface non-polarizable silver-silver chloride electrodes. 15-25 pg of human putative pheromones, clove oil and a diluent were administered to the VNO or the OE in 0.3-1 s pulses from a 0.05 mm dia cannula connected to a multichannel delivery system. Local stimulation of the VNO produces negative potentials of 1.8-11.6 mV showing adaptation. Responses are not obtained when the recording electrode is placed in the nasal respiratory mucosa. Pheromone ER-830 significantly stimulates the male VNO (P less than 0.01; n = 20), while ER-670 produces a significant effect on female subjects (P less than 0.001; n = 20). The other pheromones tested do not show significantly different effects in both male and female (P greater than 0.1). Similar quantities of odorant or diluent produce an insignificant effect on the VNO. Stimulation of the OE with clove oil produces depolarization of 12.3 +/- 3.9 mV, while pheromones do not show a significant effect. Our results show that the VNO is a functional organ in adult humans having receptor sites for human putative pheromones. PMID:1892788

  11. Internal tobacco industry research on olfactory and trigeminal nerve response to nicotine and other smoke components.

    PubMed

    Megerdichian, Christine L; Rees, Vaughan W; Wayne, Geoffrey Ferris; Connolly, Gregory N

    2007-11-01

    Evidence has shown that factors other than the central pharmacological effects of nicotine are important in promoting smoking behavior. One such non-nicotine effect includes sensory stimulation, which may promote smoking by developing learned associations with nicotine's rewarding effects, or by constituting a rewarding experience independent of nicotine. The present study used internal tobacco industry documents to examine industry efforts to understand and manipulate stimulation of the sensory nerves by tobacco smoke, and the influence of sensory stimulation on smoker behavior. Research focused on sensory nerves of the head and neck, including the olfactory nerve, which carries flavor and odor, and the trigeminal nerve, which carries irritant information. The tobacco industry maintained a systematic research program designed to elucidate an understanding of responses of sensory nerves to nicotine and other components of tobacco smoke, and attempted to develop nicotine-like compounds that would enhance sensory responses in smokers. Industry research appeared intended to aid in the development of new products with greater consumer appeal. The potential influence of sensory response in enhancing nicotine dependence through an associative mechanism was acknowledged by the tobacco industry, but evidence for research in this area was limited. These findings add to evidence of industry manipulation of sensory factors to enhance smoking behavior and may have implications for development of more effective treatment strategies, including more "acceptable" nicotine replacement therapies. PMID:17978985

  12. A SEX COMPARISON OF THE ANATOMY AND FUNCTION OF THE MAIN OLFACTORY BULB-MEDIAL AMYGDALA PROJECTION IN MICE

    PubMed Central

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

    2010-01-01

    We previously reported that some main olfactory bulb (MOB) mitral/tufted (M/T) cells send a direct projection to the ‘vomeronasal’ amygdala in female mice and selectively respond to volatile male mouse urinary odors. We asked whether MOB M/T cells that project to the vomeronasal amygdala exist in male mice and whether there is a sexually dimorphic response of these neurons to volatile male urinary pheromones. Gonadectomized male and female mice received bilateral injections of the retrograde tracer, Cholera toxin-B (CTb) into the medial amygdala (Me), which is part of the vomeronasal amygdala. All subjects were then treated with estradiol benzoate and progesterone before being exposed to volatile male urinary odors whereupon they were sacrificed 90 min later. Sections of the MOB were immunostained for Fos protein and/or CTb. Male mice, like females, displayed a small population of MOB M/T cells that project to the Me. While the general localization of these cells was similar in the two sexes, there were statistically significant sex differences in the percentage of MOB M/T cells in the anterior and posterior medial segments of the MOB that were retrogradely labeled by CTb. Male urinary volatiles stimulated equivalent, significant increases in Fos expression by MOB M/T neurons projecting to the Me in the two sexes. By contrast, in the same mice exposure to male urinary volatiles stimulated a significant increase in Fos expression by mitral cells in the accessory olfactory bulb (AOB) only in female subjects. Thus any sexually dimorphic behavioral or neuroendocrine responses to male urinary volatiles likely depend on the differential processing of these odor inputs in the AOB and/or other downstream forebrain structures after their detection by the main olfactory system. PMID:21070839

  13. β3GnT2 Maintains Adenylyl Cyclase-3 Signaling and Axon Guidance Molecule Expression in the Olfactory Epithelium

    PubMed Central

    Faden, Ashley A.; Knott, Thomas K.

    2011-01-01

    In the olfactory epithelium (OE), odorant receptor stimulation generates cAMP signals that function in both odor detection and the regulation of axon guidance molecule expression. The enzyme that synthesizes cAMP, adenylyl cyclase 3 (AC3), is coexpressed in olfactory sensory neurons (OSNs) with poly-N-acetyllactosamine (PLN) oligosaccharides determined by the glycosyltransferase β3GnT2. The loss of either enzyme results in similar defects in olfactory bulb (OB) innervation and OSN survival, suggesting that glycosylation may be important for AC3 function. We show here that AC3 is extensively modified with N-linked PLN, which is essential for AC3 activity and localization. On Western blots, AC3 from the wild-type OE migrates diffusely as a heavily glycosylated 200 kDa band that interacts with the PLN-binding lectin LEA. AC3 from the β3GnT2−/− OE loses these PLN modifications, migrating instead as a 140 kDa glycoprotein. Furthermore, basal and forskolin-stimulated cAMP production is reduced 80–90% in the β3GnT2−/− OE. Although AC3 traffics normally to null OSN cilia, it is absent from axon projections that aberrantly target the OB. The cAMP-dependent guidance receptor neuropilin-1 is also lost from β3GnT2−/− OSNs and axons, while semaphorin-3A ligand expression is upregulated. In addition, kirrel2, a mosaically expressed adhesion molecule that functions in axon sorting, is absent from β3GnT2−/− OB projections. These results demonstrate that PLN glycans are essential in OSNs for proper AC3 localization and function. We propose that the loss of cAMP-dependent guidance cues is also a critical factor in the severe axon guidance defects observed in β3GnT2−/− mice. PMID:21525298

  14. 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

  15. Mechanisms of neuronal chloride accumulation in intact mouse olfactory epithelium

    PubMed Central

    Nickell, William T; Kleene, Nancy K; Kleene, Steven J

    2007-01-01

    When olfactory receptor neurons respond to odours, a depolarizing Cl− efflux is a substantial part of the response. This requires that the resting neuron accumulate Cl− against an electrochemical gradient. In isolated olfactory receptor neurons, the Na+–K+–2Cl− cotransporter NKCC1 is essential for Cl− accumulation. However, in intact epithelium, a robust electrical olfactory response persists in mice lacking NKCC1. This response is largely due to a neuronal Cl− efflux. It thus appears that NKCC1 is an important part of a more complex system of Cl− accumulation. To identify the remaining transport proteins, we first screened by RT-PCR for 21 Cl− transporters in mouse nasal tissue containing olfactory mucosa. For most of the Cl− transporters, the presence of mRNA was demonstrated. We also investigated the effects of pharmacological block or genetic ablation of Cl− transporters on the olfactory field potential, the electroolfactogram (EOG). Mice lacking the common Cl−/HCO3− exchanger AE2 had normal EOGs. Block of NKCC cotransport with bumetanide reduced the EOG in epithelia from wild-type mice but had no effect in mice lacking NKCC1. Hydrochlorothiazide, a blocker of the Na+–Cl− cotransporter, had only a small effect. DIDS, a blocker of some KCC cotransporters and Cl−/HCO3− exchangers, reduced the EOG in epithelia from both wild-type and NKCC1 knockout mice. A combination of bumetanide and DIDS decreased the response more than either drug alone. However, no combination of drugs completely abolished the Cl− component of the response. These results support the involvement of both NKCC1 and one or more DIDS-sensitive transporters in Cl− accumulation in olfactory receptor neurons. PMID:17656441

  16. Mechanisms of neuronal chloride accumulation in intact mouse olfactory epithelium.

    PubMed

    Nickell, William T; Kleene, Nancy K; Kleene, Steven J

    2007-09-15

    When olfactory receptor neurons respond to odours, a depolarizing Cl(-) efflux is a substantial part of the response. This requires that the resting neuron accumulate Cl(-) against an electrochemical gradient. In isolated olfactory receptor neurons, the Na(+)-K(+)-2Cl(-) cotransporter NKCC1 is essential for Cl(-) accumulation. However, in intact epithelium, a robust electrical olfactory response persists in mice lacking NKCC1. This response is largely due to a neuronal Cl(-) efflux. It thus appears that NKCC1 is an important part of a more complex system of Cl(-) accumulation. To identify the remaining transport proteins, we first screened by RT-PCR for 21 Cl(-) transporters in mouse nasal tissue containing olfactory mucosa. For most of the Cl(-) transporters, the presence of mRNA was demonstrated. We also investigated the effects of pharmacological block or genetic ablation of Cl(-) transporters on the olfactory field potential, the electroolfactogram (EOG). Mice lacking the common Cl(-)/HCO(3)(-) exchanger AE2 had normal EOGs. Block of NKCC cotransport with bumetanide reduced the EOG in epithelia from wild-type mice but had no effect in mice lacking NKCC1. Hydrochlorothiazide, a blocker of the Na(+)-Cl(-) cotransporter, had only a small effect. DIDS, a blocker of some KCC cotransporters and Cl(-)/HCO(3)(-) exchangers, reduced the EOG in epithelia from both wild-type and NKCC1 knockout mice. A combination of bumetanide and DIDS decreased the response more than either drug alone. However, no combination of drugs completely abolished the Cl(-) component of the response. These results support the involvement of both NKCC1 and one or more DIDS-sensitive transporters in Cl(-) accumulation in olfactory receptor neurons. PMID:17656441

  17. 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

  18. The Role of Dopamine in Drosophila Larval Classical Olfactory Conditioning

    PubMed Central

    Han, Kyung-An; Stocker, Reinhard F.; Thum, Andreas S.

    2009-01-01

    Learning and memory is not an attribute of higher animals. Even Drosophila larvae are able to form and recall an association of a given odor with an aversive or appetitive gustatory reinforcer. As the Drosophila larva has turned into a particularly simple model for studying odor processing, a detailed neuronal and functional map of the olfactory pathway is available up to the third order neurons in the mushroom bodies. At this point, a convergence of olfactory processing and gustatory reinforcement is suggested to underlie associative memory formation. The dopaminergic system was shown to be involved in mammalian and insect olfactory conditioning. To analyze the anatomy and function of the larval dopaminergic system, we first characterize dopaminergic neurons immunohistochemically up to the single cell level and subsequent test for the effects of distortions in the dopamine system upon aversive (odor-salt) as well as appetitive (odor-sugar) associative learning. Single cell analysis suggests that dopaminergic neurons do not directly connect gustatory input in the larval suboesophageal ganglion to olfactory information in the mushroom bodies. However, a number of dopaminergic neurons innervate different regions of the brain, including protocerebra, mushroom bodies and suboesophageal ganglion. We found that dopamine receptors are highly enriched in the mushroom bodies and that aversive and appetitive olfactory learning is strongly impaired in dopamine receptor mutants. Genetically interfering with dopaminergic signaling supports this finding, although our data do not exclude on naïve odor and sugar preferences of the larvae. Our data suggest that dopaminergic neurons provide input to different brain regions including protocerebra, suboesophageal ganglion and mushroom bodies by more than one route. We therefore propose that different types of dopaminergic neurons might be involved in different types of signaling necessary for aversive and appetitive olfactory memory

  19. Phylogenic studies on the olfactory system in vertebrates.

    PubMed

    Taniguchi, Kazuyuki; Taniguchi, Kazumi

    2014-06-01

    The olfactory receptor organs and their primary centers are classified into several types. The receptor organs are divided into fish-type olfactory epithelium (OE), mammal-type OE, middle chamber epithelium (MCE), lower chamber epithelium (LCE), recess epithelium, septal olfactory organ of Masera (SO