Levels-of-processing effects on a task of olfactory naming.

PubMed

Royet, Jean-Pierre; Koenig, Olivier; Paugam-Moisy, Helene; Puzenat, Didier; Chasse, Jean-Luc

2004-02-01

The effects of odor processing were investigated at various analytical levels, from simple sensory analysis to deep or semantic analysis, on a subsequent task of odor naming. Students (106 women, 23.6 +/- 5.5 yr. old; 65 men, 25.1 +/- 7.1 yr. old) were tested. The experimental procedure included two successive sessions, a first session to characterize a set of 30 odors with criteria that used various depths of processing and a second session to name the odors as quickly as possible. Four processing conditions rated the odors using descriptors before naming the odor. The control condition did not rate the odors before naming. The processing conditions were based on lower-level olfactory judgments (superficial processing), higher-level olfactory-gustatory-somesthetic judgments (deep processing), and higher-level nonolfactory judgments (Deep-Control processing, with subjects rating odors with auditory and visual descriptors). One experimental condition successively grouped lower- and higher-level olfactory judgments (Superficial-Deep processing). A naming index which depended on response accuracy and the subjects' response time were calculated. Odor naming was modified for 18 out of 30 odorants as a function of the level of processing required. For 94.5% of significant variations, the scores for odor naming were higher following those tasks for which it was hypothesized that the necessary olfactory processing was carried out at a deeper level. Performance in the naming task was progressively improved as follows: no rating of odors, then superficial, deep-control, deep, and superficial-deep processings. These data show that the deepest olfactory encoding was later associated with progressively higher performance in naming.

Algal and water-quality data for Rapid Creek and Canyon Lake near Rapid City, South Dakota, 2007

USGS Publications Warehouse

Hoogestraat, Galen K.; Putnam, Larry D.; Graham, Jennifer L.

2008-01-01

This report summarizes the results of algae and water-quality sampling on Rapid Creek and Canyon Lake during May and September 2007. The overall purpose of the study was to determine the algal community composition of Rapid Creek and Canyon Lake in relation to organisms that are known producers of unwanted tastes and odors in drinking-water supplies. Algal assemblage structure (phytoplankton and periphyton) was examined at 16 sites on Rapid Creek and Canyon Lake during May and September 2007, and actinomycetes bacteria were sampled at the Rapid City water treatment plant intake in May 2007, to determine if taste-and-odor producing organisms were present. During the May 2007 sampling, 3 Rapid Creek sites and 4 Canyon Lake sites were quantitatively sampled for phytoplankton in the water column, 7 Rapid Creek sites were quantitatively sampled for attached periphyton, and 4 lake and retention pond sites were qualitatively sampled for periphyton. Five Rapid Creek sites were sampled for geosmin and 2-methylisoborneol, two common taste-and-odor causing compounds known to affect water supplies. During the September 2007 sampling, 4 Rapid Creek sites were quantitatively sampled for attached periphyton, and 3 Canyon Lake sites were qualitatively sampled for periphyton. Water temperature, dissolved oxygen, pH, and specific conductance were measured during each sampling event. Methods of collection and sample analysis are presented for the various types of biological and chemical constituent samples. Diatoms comprised 91-100 percent of the total algal biovolume in periphyton samples collected during May and September. Cyanobacteria (also called blue-green algae) were detected in 7 of the 11 quantitative periphyton samples and ranged from 0.01 to 2.0 percent of the total biovolume. Cyanobacteria were present in 3 of the 7 phytoplankton samples collected in May, but the relative biovolumes were small (0.01-0.2 percent). Six of seven qualitative samples collected from Canyon Lake and retention ponds during May and September also contained cyanobacteria. Geosmin and 2-methylisoborneol concentrations were less than detection limits (0.005 ug/L) in all five of the Rapid Creek samples collected in May. Actinomycetes bacteria were present at the water treatment plant intake in May 2007, at a concentration of 6 colonies per milliliter. During this study, no taste-and-odor problems with the drinking water within the study area were reported. However, the presence of cyanobacterial taxa known to contain taste-and-odor producing strains (such as Leptolyngbya, Phormidium, and Anabaena) indicates the potential for taste-and-odor problems under certain physical and chemical conditions.

Visualizing odorant receptor trafficking in living cells down to the single-molecule level

PubMed Central

Jacquier, V.; Prummer, M.; Segura, J.-M.; Pick, H.; Vogel, H.

2006-01-01

Despite the importance of trafficking for regulating G protein-coupled receptor signaling, for many members of the seven transmembrane helix protein family, such as odorant receptors, little is known about this process in live cells. Here, the complete life cycle of the human odorant receptor OR17-40 was directly monitored in living cells by ensemble and single-molecule imaging, using a double-labeling strategy. While the overall, intracellular trafficking of the receptor was visualized continuously by using a GFP tag, selective imaging of cell surface receptors was achieved by pulse-labeling an acyl carrier protein tag. We found that OR17-40 efficiently translocated to the plasma membrane only at low expression, whereas at higher biosynthesis the receptor accumulated in intracellular compartments. Receptors in the plasma membrane showed high turnover resulting from constitutive internalization along the clathrin pathway, even in the absence of ligand. Single-molecule microscopy allowed monitoring of the early, dynamic processes in odorant receptor signaling. Although mobile receptors initially diffused either freely or within domains of various sizes, binding of an agonist or an antagonist increased partitioning of receptors into small domains of ≈190 nm, which likely are precursors of clathrin-coated pits. The binding of a ligand, therefore, resulted in modulation of the continuous, constitutive internalization. After endocytosis, receptors were directed to early endosomes for recycling. This unique mechanism of continuous internalization and recycling of OR17-40 might be instrumental in allowing rapid recovery of odor perception. PMID:16980412

Rapid Decision-Making with Side-Specific Perceptual Discrimination in Ants

PubMed Central

Stroeymeyt, Nathalie; Guerrieri, Fernando J.; van Zweden, Jelle S.; d'Ettorre, Patrizia

2010-01-01

Background Timely decision making is crucial for survival and reproduction. Organisms often face a speed-accuracy trade-off, as fully informed, accurate decisions require time-consuming gathering and treatment of information. Optimal strategies for decision-making should therefore vary depending on the context. In mammals, there is mounting evidence that multiple systems of perceptual discrimination based on different neural circuits emphasize either fast responses or accurate treatment of stimuli depending on the context. Methodology/Principal Findings We used the ant Camponotus aethiops to test the prediction that fast information processing achieved through direct neural pathways should be favored in situations where quick reactions are adaptive. Social insects discriminate readily between harmless group-members and dangerous strangers using easily accessible cuticular hydrocarbons as nestmate recognition cues. We show that i) tethered ants display rapid aggressive reactions upon presentation of non-nestmate odor (120 to 160 ms); ii) ants' aggressiveness towards non-nestmates can be specifically reduced by exposure to non-nestmate odor only, showing that social interactions are not required to alter responses towards non-nestmates; iii) decision-making by ants does not require information transfer between brain hemispheres, but relies on side-specific decision rules. Conclusions/Significance Our results strongly suggest that first-order olfactory processing centers (up to the antennal lobes) are likely to play a key role in ant nestmate recognition. We hypothesize that the coarse level of discrimination achieved in the antennal lobes early in odor processing provides enough information to determine appropriate behavioral responses towards non-nestmates. This asks for a reappraisal of the mechanisms underlying social recognition in insects. PMID:20808782

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

PubMed Central

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

2014-01-01

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

Analgesia Is Enhanced by Providing Information regarding Good Outcomes Associated with an Odor: Placebo Effects in Aromatherapy?

PubMed Central

Masaoka, Yuri; Kawase, Akiko; Homma, Ikuo

2013-01-01

No previous report has described whether information regarding an odor used in aromatherapy has placebo effects. We investigated whether placebo analgesia was engendered by verbal information regarding the analgesic effects of an odor. Twelve of 24 subjects were provided with the information that a lavender odor would reduce pain (informed), whereas the other 12 subjects were not (not-informed). Concurrent with respiration recording, the subjects were administered a lavender-odor or no-odor treatment during application of painful stimulation to the forefinger. The subjects reported their experience of pain and its unpleasantness on a visual analogue scale after the painful stimulation. The lavender-odor treatment significantly alleviated pain and unpleasantness compared with the no-odor treatment in the informed (P < 0.01) and not-informed groups (P < 0.05). The no-odor treatment in the informed group significantly alleviated pain and unpleasantness compared with both the no-odor and lavender-odor treatments in the not-informed group (P < 0.05). Rapid and shallow breathing induced by the painful stimulation became slow and deep during the lavender-odor and no-odor treatments in both groups. Information regarding a lavender odor, the lavender odor itself, and slower breathing contributed to reduced perceptions of pain and unpleasantness during painful stimulation, suggesting that placebo effects significantly contribute to analgesia in aromatherapy. PMID:23840270

Functional Neuronal Processing of Human Body Odors

PubMed Central

Lundström, Johan N.; Olsson, Mats J.

2013-01-01

Body odors carry informational cues of great importance for individuals across a wide range of species, and signals hidden within the body odor cocktail are known to regulate several key behaviors in animals. For a long time, the notion that humans may be among these species has been dismissed. We now know, however, that each human has a unique odor signature that carries information related to his or her genetic makeup, as well as information about personal environmental variables, such as diet and hygiene. Although a substantial number of studies have investigated the behavioral effects of body odors, only a handful have studied central processing. Recent studies have, however, demonstrated that the human brain responds to fear signals hidden within the body odor cocktail, is able to extract kin specific signals, and processes body odors differently than other perceptually similar odors. In this chapter, we provide an overview of the current knowledge of how the human brain processes body odors and the potential importance these signals have for us in everyday life. PMID:20831940

Coordinate synaptic mechanisms contributing to olfactory cortical adaptation.

PubMed

Best, Aaron R; Wilson, Donald A

2004-01-21

Anterior piriform cortex (aPCX) neurons rapidly filter repetitive odor stimuli despite relatively maintained input from mitral cells. This cortical adaptation is correlated with short-term depression of afferent synapses, in vivo. The purpose of this study was to elucidate mechanisms underlying this nonassociative neural plasticity using in vivo and in vitro preparations and to determine its role in cortical odor adaptation. Lateral olfactory tract (LOT)-evoked responses were recorded in rat aPCX coronal slices. Extracellular and intracellular potentials were recorded before and after simulated odor stimulation of the LOT. Results were compared with in vivo intracellular recordings from aPCX layer II/III neurons and field recordings in urethane-anesthetized rats stimulated with odorants. The onset, time course, and extent of LOT synaptic depression during both in vitro electrical and in vivo odorant stimulation methods were similar. Similar to the odor specificity of cortical odor adaptation in vivo, there was no evidence of heterosynaptic depression between independent inputs in vitro. In vitro evidence suggests at least two mechanisms contribute to this activity-dependent synaptic depression: a rapidly recovering presynaptic depression during the initial 10-20 sec of the post-train recovery period and a longer lasting (approximately 120 sec) depression that can be blocked by the metabotropic glutamate receptor (mGluR) II/III antagonist (RS)-alpha-cyclopropyl-4-phosphonophenylglycine (CPPG) and by the beta-adrenergic receptor agonist isoproterenol. Importantly, in line with the in vitro findings, both adaptation of odor responses in the beta (15-35 Hz) spectral range and the associated synaptic depression can also be blocked by intracortical infusion of CPPG in vivo.

Coordinate Synaptic Mechanisms Contributing to Olfactory Cortical Adaptation

PubMed Central

Best, Aaron R.; Wilson, Donald A.

2008-01-01

Anterior piriform cortex (aPCX) neurons rapidly filter repetitive odor stimuli despite relatively maintained input from mitral cells. This cortical adaptation is correlated with short-term depression of afferent synapses, in vivo. The purpose of this study was to elucidate mechanisms underlying this nonassociative neural plasticity using in vivo and in vitro preparations and to determine its role in cortical odor adaptation. Lateral olfactory tract (LOT)-evoked responses were recorded in rat aPCX coronal slices. Extracellular and intracellular potentials were recorded before and after simulated odor stimulation of the LOT. Results were compared with in vivo intracellular recordings from aPCX layer II/III neurons and field recordings in urethane-anesthetized rats stimulated with odorants. The onset, time course, and extent of LOT synaptic depression during both in vitro electrical and in vivo odorant stimulation methods were similar. Similar to the odor specificity of cortical odor adaptation in vivo, there was no evidence of heterosynaptic depression between independent inputs in vitro. In vitro evidence suggests at least two mechanisms contribute to this activity-dependent synaptic depression: a rapidly recovering presynaptic depression during the initial 10–20 sec of the post-train recovery period and a longer lasting (~120 sec) depression that can be blocked by the metabotropic glutamate receptor (mGluR) II/III antagonist (RS)-α-cyclopropyl-4-phosphonophenylglycine (CPPG) and by the β-adrenergic receptor agonist isoproterenol. Importantly, in line with the in vitro findings, both adaptation of odor responses in the β (15–35 Hz) spectral range and the associated synaptic depression can also be blocked by intracortical infusion of CPPG in vivo. PMID:14736851

Honeybees Learn Odour Mixtures via a Selection of Key Odorants

PubMed Central

Reinhard, Judith; Sinclair, Michael; Srinivasan, Mandyam V.; Claudianos, Charles

2010-01-01

Background The honeybee has to detect, process and learn numerous complex odours from her natural environment on a daily basis. Most of these odours are floral scents, which are mixtures of dozens of different odorants. To date, it is still unclear how the bee brain unravels the complex information contained in scent mixtures. Methodology/Principal Findings This study investigates learning of complex odour mixtures in honeybees using a simple olfactory conditioning procedure, the Proboscis-Extension-Reflex (PER) paradigm. Restrained honeybees were trained to three scent mixtures composed of 14 floral odorants each, and then tested with the individual odorants of each mixture. Bees did not respond to all odorants of a mixture equally: They responded well to a selection of key odorants, which were unique for each of the three scent mixtures. Bees showed less or very little response to the other odorants of the mixtures. The bees' response to mixtures composed of only the key odorants was as good as to the original mixtures of 14 odorants. A mixture composed of the other, non-key-odorants elicited a significantly lower response. Neither an odorant's volatility or molecular structure, nor learning efficiencies for individual odorants affected whether an odorant became a key odorant for a particular mixture. Odorant concentration had a positive effect, with odorants at high concentration likely to become key odorants. Conclusions/Significance Our study suggests that the brain processes complex scent mixtures by predominantly learning information from selected key odorants. Our observations on key odorant learning lend significant support to previous work on olfactory learning and mixture processing in honeybees. PMID:20161714

Functional neuronal processing of human body odors.

PubMed

Lundström, Johan N; Olsson, Mats J

2010-01-01

Body odors carry informational cues of great importance for individuals across a wide range of species, and signals hidden within the body odor cocktail are known to regulate several key behaviors in animals. For a long time, the notion that humans may be among these species has been dismissed. We now know, however, that each human has a unique odor signature that carries information related to his or her genetic makeup, as well as information about personal environmental variables, such as diet and hygiene. Although a substantial number of studies have investigated the behavioral effects of body odors, only a handful have studied central processing. Recent studies have, however, demonstrated that the human brain responds to fear signals hidden within the body odor cocktail, is able to extract kin specific signals, and processes body odors differently than other perceptually similar odors. In this chapter, we provide an overview of the current knowledge of how the human brain processes body odors and the potential importance these signals have for us in everyday life. Copyright © 2010 Elsevier Inc. All rights reserved.

The perception of odor objects in everyday life: a review on the processing of odor mixtures

PubMed Central

Thomas-Danguin, Thierry; Sinding, Charlotte; Romagny, Sébastien; El Mountassir, Fouzia; Atanasova, Boriana; Le Berre, Elodie; Le Bon, Anne-Marie; Coureaud, Gérard

2014-01-01

Smelling monomolecular odors hardly ever occurs in everyday life, and the daily functioning of the sense of smell relies primarily on the processing of complex mixtures of volatiles that are present in the environment (e.g., emanating from food or conspecifics). Such processing allows for the instantaneous recognition and categorization of smells and also for the discrimination of odors among others to extract relevant information and to adapt efficiently in different contexts. The neurophysiological mechanisms underpinning this highly efficient analysis of complex mixtures of odorants is beginning to be unraveled and support the idea that olfaction, as vision and audition, relies on odor-objects encoding. This configural processing of odor mixtures, which is empirically subject to important applications in our societies (e.g., the art of perfumers, flavorists, and wine makers), has been scientifically studied only during the last decades. This processing depends on many individual factors, among which are the developmental stage, lifestyle, physiological and mood state, and cognitive skills; this processing also presents striking similarities between species. The present review gathers the recent findings, as observed in animals, healthy subjects, and/or individuals with affective disorders, supporting the perception of complex odor stimuli as odor objects. It also discusses peripheral to central processing, and cognitive and behavioral significance. Finally, this review highlights that the study of odor mixtures is an original window allowing for the investigation of daily olfaction and emphasizes the need for knowledge about the underlying biological processes, which appear to be crucial for our representation and adaptation to the chemical environment. PMID:24917831

Differential processing of social chemosignals obtained from potential partners in regards to gender and sexual orientation.

PubMed

Lübke, Katrin T; Hoenen, Matthias; Pause, Bettina M

2012-03-17

On an individual level, human body odors carry information about whether a person is an eligible mate. The current studies investigate if body odors also transmit information about individuals being potential partners in more general terms, namely in regards to gender and sexual orientation. In study 1, 14 gay and 14 heterosexual men were presented with body odors obtained from potential partners (gay male and heterosexual female body odors, respectively) and heterosexual male body odor as a control. In study 2, 14 lesbian and 14 heterosexual women were presented with lesbian female and heterosexual male body odors representing body odors of potential partners, and heterosexual female body odor as a control. Central nervous processing was analyzed using chemosensory event-related potentials and current source density analysis (64-channel EEG recording). Gay and heterosexual men responded with shorter P2 latencies to the body odors of their preferred sexual partners, and lesbian women responded with shorter P2 latencies to body odors of their preferred gender. In response to heterosexual male body odors, lesbian women displayed the most pronounced P3 amplitude, and distinct neuronal activation in medial frontal and parietal neocortical areas. A similar pattern of neuronal activation was observed in gay men when presented with heterosexual male body odor. Both the early processing advantage (P2) for desirable partners' body odors as well as the enhanced evaluative processing (P3, CSD) of undesirable partners' body odors suggest that human body odors indeed carry information about individuals being potential partners in terms of gender and sexual orientation. Copyright © 2011 Elsevier B.V. All rights reserved.

No effect of odor-induced memory reactivation during REM sleep on declarative memory stability

PubMed Central

Cordi, Maren J.; Diekelmann, Susanne; Born, Jan; Rasch, Björn

2014-01-01

Memory reactivations in hippocampal brain areas are critically involved in memory consolidation processes during sleep. In particular, specific firing patterns of hippocampal place cells observed during learning are replayed during subsequent sleep and rest in rodents. In humans, experimentally inducing hippocampal memory reactivations during slow-wave sleep (but not during wakefulness) benefits consolidation and immediately stabilizes declarative memories against future interference. Importantly, spontaneous hippocampal replay activity can also be observed during rapid eye movement (REM) sleep and some authors have suggested that replay during REM sleep is related to processes of memory consolidation. However, the functional role of reactivations during REM sleep for memory stability is still unclear. Here, we reactivated memories during REM sleep and examined its consequences for the stability of declarative memories. After 3 h of early, slow-wave sleep (SWS) rich sleep, 16 healthy young adults learned a 2-D object location task in the presence of a contextual odor. During subsequent REM sleep, participants were either re-exposed to the odor or to an odorless vehicle, in a counterbalanced within subject design. Reactivation was followed by an interference learning task to probe memory stability after awakening. We show that odor-induced memory reactivation during REM sleep does not stabilize memories against future interference. We propose that the beneficial effect of reactivation during sleep on memory stability might be critically linked to processes characterizing SWS including, e.g., slow oscillatory activity, sleep spindles, or low cholinergic tone, which are required for a successful redistribution of memories from medial temporal lobe regions to neocortical long-term stores. PMID:25225474

Identification and characterization of volatile components causing the characteristic flavor in miso (Japanese fermented soybean paste) and heat-processed miso products.

PubMed

Kumazawa, Kenji; Kaneko, Shu; Nishimura, Osamu

2013-12-11

The aroma concentrates of two types of raw miso (traditional Japanese fermented soybean paste) were prepared by combining solid phase extraction (SPE) and solvent-assisted flavor evaporation (SAFE) techniques. The aroma extract dilution analysis (AEDA) applied to the volatile fraction revealed 39 odor-active peaks with FD factors between 4(1) and 4(8). Among the perceived odorants, 32 odorants were identified or tentatively identified from the 39 odor-active peaks, and the newly identified odorants for the miso were half of them. Furthermore, by comparison of the FD factors between the raw miso and heat-processed miso, it was found that one increasing odorant (methional) and three decreasing odorants (1-octen-3-one, (Z)-1,5-octadien-3-one, and trans-4,5-epoxy-(E)-2-decenal) contributed to the flavor change during the heat processing. This finding suggested that the flavor change in the raw miso during heat processing is attributed to relatively few odorant changes. In addition, it was assumed that the amino acids included in the miso have a significant influence on the remarkable disappearance of the three decreasing odorants.

Use of Alum for Odor Reduction in Sludge and Biosolids from Different Wastewater Treatment Processes.

PubMed

Gruchlik, Yolanta; Fouché, Lise; Joll, Cynthia A; Heitz, Anna

2017-12-01

  Applicability of alum addition to wastewater sludge and biosolids produced from different treatment processes was evaluated as a means of odor reduction. Four water resource recovery facilities (WRRFs) were chosen for this study: two used mesophilic anaerobic digestion and two used oxidation ditch processes. The experiments were conducted on a laboratory scale and in all cases the alum was added prior to dewatering. This is the first report of the application of alum for odor reduction in oxidation ditch processes. Alum addition was effective in reducing odors in anaerobically digested biosolids. Addition of 4% alum to anaerobically digested liquid biosolids prior to dewatering resulted in a 60% reduction in the peak odor concentration in the laboratory dewatered cake, relative to the control sample. Alum addition did not reduce odors in dewatered sludge from oxidation ditch processes.

Sniffing shapes the dynamics of olfactory bulb gamma oscillations in awake behaving rats.

PubMed

Rosero, Mario A; Aylwin, María L

2011-09-01

Mammals actively sample the environment for relevant olfactory objects. This active sampling is revealed by rapid changes in respiratory rate that influence the olfactory input. Yet the role of sniffing in shaping the neural responses to odorants has not been elucidated. In the olfactory bulb (OB), odorant-evoked gamma oscillations reflect the synchronous activity of mitral/tufted cells, a proposed mechanism for odorant representation. Here we examined the effect of sniffing frequency on the odorant-evoked gamma oscillations in the OB. We simultaneously recorded the respiratory rate and the local field potential while rats performed a lick/no-lick olfactory discrimination task with low odorant concentrations. High-frequency sniffing (HFS) augmented the power of gamma oscillations, suggesting an increase in the sensitivity to odorants. By contrast, coupling of the gamma oscillations to the sniff cycle and the amplitude of individual bursts were not modified by the respiratory rate. However, HFS prolonged the overall response to odorants and increased the frequency of the gamma oscillations, indicating that HFS reduces the adaptation to continuous odorant stimulation. Therefore, the increase in gamma power during HFS is the result of more frequent gamma bursts and the extended response to odorants. As odorant discrimination can be performed in a single sniff, a reduction in the adaptation mediated by HFS of novel odorants may facilitate odorant memory formation for subsequent odorant identification. Finally, these results corroborate that olfactory sampling should be integrated to the study of odorant coding in behaving animals. © 2011 The Authors. European Journal of Neuroscience © 2011 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.

SwarmSight: Real-time Tracking of Insect Antenna Movements and Proboscis Extension Reflex Using a Common Preparation and Conventional Hardware

PubMed Central

Birgiolas, Justas; Jernigan, Christopher M.; Gerkin, Richard C.; Smith, Brian H.; Crook, Sharon M.

2017-01-01

Many scientifically and agriculturally important insects use antennae to detect the presence of volatile chemical compounds and extend their proboscis during feeding. The ability to rapidly obtain high-resolution measurements of natural antenna and proboscis movements and assess how they change in response to chemical, developmental, and genetic manipulations can aid the understanding of insect behavior. By extending our previous work on assessing aggregate insect swarm or animal group movements from natural and laboratory videos using the video analysis software SwarmSight, we developed a novel, free, and open-source software module, SwarmSight Appendage Tracking (SwarmSight.org) for frame-by-frame tracking of insect antenna and proboscis positions from conventional web camera videos using conventional computers. The software processes frames about 120 times faster than humans, performs at better than human accuracy, and, using 30 frames per second (fps) videos, can capture antennal dynamics up to 15 Hz. The software was used to track the antennal response of honey bees to two odors and found significant mean antennal retractions away from the odor source about 1 s after odor presentation. We observed antenna position density heat map cluster formation and cluster and mean angle dependence on odor concentration. PMID:29364251

Recruits of the stingless bee Scaptotrigona pectoralis learn food odors from the nest atmosphere.

PubMed

Reichle, Christian; Jarau, Stefan; Aguilar, Ingrid; Ayasse, Manfred

2010-05-01

The ability to learn food odors inside the nest and to associate them with food sources in the field is of essential importance for the recruitment of nestmates in social bees. We investigated odor learning by workers within the hive and the influence of these odors on their food choice in the field in the stingless bee Scaptotrigona pectoralis. During the experiments, recruited bees had to choose between two feeders, one with an odor that was present inside the nest during the recruitment process, and one with an unknown odor. In all experiments with different odor combinations (linalool/phenylacetaldehyde, geraniol/eugenol) a significant majority of bees visited the feeder with the odor they had experienced in their nest (chi (2)-tests; p < 0.05). By contrast, the bees showed no preference for one of two feeders when they were either baited with the same odor (linalool) or contained no odor. Our results clearly show that naïve workers of S. pectoralis can learn the odor of a food source during the recruitment process from the nest atmosphere and that their subsequent food search in the field is influenced by the learned odor.

Recruits of the stingless bee Scaptotrigona pectoralis learn food odors from the nest atmosphere

NASA Astrophysics Data System (ADS)

Reichle, Christian; Jarau, Stefan; Aguilar, Ingrid; Ayasse, Manfred

2010-05-01

The ability to learn food odors inside the nest and to associate them with food sources in the field is of essential importance for the recruitment of nestmates in social bees. We investigated odor learning by workers within the hive and the influence of these odors on their food choice in the field in the stingless bee Scaptotrigona pectoralis. During the experiments, recruited bees had to choose between two feeders, one with an odor that was present inside the nest during the recruitment process, and one with an unknown odor. In all experiments with different odor combinations (linalool/phenylacetaldehyde, geraniol/eugenol) a significant majority of bees visited the feeder with the odor they had experienced in their nest ( χ 2-tests; p < 0.05). By contrast, the bees showed no preference for one of two feeders when they were either baited with the same odor (linalool) or contained no odor. Our results clearly show that naïve workers of S. pectoralis can learn the odor of a food source during the recruitment process from the nest atmosphere and that their subsequent food search in the field is influenced by the learned odor.

Recognition of the Component Odors in Mixtures

PubMed Central

Fletcher, Dane B; Hettinger, Thomas P

2017-01-01

Abstract Natural olfactory stimuli are volatile-chemical mixtures in which relative perceptual saliencies determine which odor-components are identified. Odor identification also depends on rapid selective adaptation, as shown for 4 odor stimuli in an earlier experimental simulation of natural conditions. Adapt-test pairs of mixtures of water-soluble, distinct odor stimuli with chemical features in common were studied. Identification decreased for adapted components but increased for unadapted mixture-suppressed components, showing compound identities were retained, not degraded to individual molecular features. Four additional odor stimuli, 1 with 2 perceptible odor notes, and an added “water-adapted” control tested whether this finding would generalize to other 4-compound sets. Selective adaptation of mixtures of the compounds (odors): 3 mM benzaldehyde (cherry), 5 mM maltol (caramel), 1 mM guaiacol (smoke), and 4 mM methyl anthranilate (grape-smoke) again reciprocally unmasked odors of mixture-suppressed components in 2-, 3-, and 4-component mixtures with 2 exceptions. The cherry note of “benzaldehyde” (itself) and the shared note of “methyl anthranilate and guaiacol” (together) were more readily identified. The pervasive mixture-component dominance and dynamic perceptual salience may be mediated through peripheral adaptation and central mutual inhibition of neural responses. Originating in individual olfactory receptor variants, it limits odor identification and provides analytic properties for momentary recognition of a few remaining mixture-components. PMID:28641388

Recognition memory for social and non-social odors: differential effects of neurotoxic lesions to the hippocampus and perirhinal cortex.

PubMed

Feinberg, Leila M; Allen, Timothy A; Ly, Denise; Fortin, Norbert J

2012-01-01

The contributions of the hippocampus (HC) and perirhinal cortex (PER) to recognition memory are currently topics of debate in neuroscience. Here we used a rapidly-learned (seconds) spontaneous novel odor recognition paradigm to assess the effects of pre-training N-methyl-D-aspartate lesions to the HC or PER on odor recognition memory. We tested memory for both social and non-social odor stimuli. Social odors were acquired from conspecifics, while non-social odors were household spices. Conspecific odor stimuli are ethologically-relevant and have a high degree of overlapping features compared to non-social household spices. Various retention intervals (5 min, 20 min, 1h, 24h, or 48 h) were used between study and test phases, each with a unique odor pair, to assess changes in novelty preference over time. Consistent with findings in other paradigms, modalities, and species, we found that HC lesions yielded no significant recognition memory deficits. In contrast, PER lesions caused significant deficits for social odor recognition memory at long retention intervals, demonstrating a critical role for PER in long-term memory for social odors. PER lesions had no effect on memory for non-social odors. The results are consistent with a general role for PER in long-term recognition memory for stimuli that have a high degree of overlapping features, which must be distinguished by conjunctive representations. Copyright © 2011 Elsevier Inc. All rights reserved.

Responses to novel odors mediate maternal behavior and concaveation in gerbils.

PubMed

Clark, M M; Spencer, C A; Galef, B G

1986-01-01

In a series of three experiments we examined: (Experiment 1) responses to novel odors by early- and late-maturing not-pregnant, pregnant, nursing and postweaning female Mongolian gerbils, (Experiment 2) the response of the same eight groups of female gerbils to unfamiliar pups, and (Experiment 3) the rate of induction of maternal behavior by concaveation in early- and late-maturing nulliparous gerbils. We found: (1) that those females that responded relatively positively to novel odors in Experiment 1 were more likely to retrieve and less likely to attack unfamiliar pups in Experiment 2 than those females responding relatively negatively to novel odors in Experiment 1, and (2) that early-maturing nulliparous gerbils both responded more positively to novel odors and exhibited more rapid induction of maternal behavior by concaveation than late-maturing nulliparous gerbils. The results both confirm and extend Fleming and Rosenblatt's (1974) hypothesis that differences in response to novel odors mediate individual differences in maternal responsiveness.

Complementary codes for odor identity and intensity in olfactory cortex

PubMed Central

Bolding, Kevin A; Franks, Kevin M

2017-01-01

The ability to represent both stimulus identity and intensity is fundamental for perception. Using large-scale population recordings in awake mice, we find distinct coding strategies facilitate non-interfering representations of odor identity and intensity in piriform cortex. Simply knowing which neurons were activated is sufficient to accurately represent odor identity, with no additional information about identity provided by spike time or spike count. Decoding analyses indicate that cortical odor representations are not sparse. Odorant concentration had no systematic effect on spike counts, indicating that rate cannot encode intensity. Instead, odor intensity can be encoded by temporal features of the population response. We found a subpopulation of rapid, largely concentration-invariant responses was followed by another population of responses whose latencies systematically decreased at higher concentrations. Cortical inhibition transforms olfactory bulb output to sharpen these dynamics. Our data therefore reveal complementary coding strategies that can selectively represent distinct features of a stimulus. DOI: http://dx.doi.org/10.7554/eLife.22630.001 PMID:28379135

[Evaluating the Significance of Odor Gas Released During the Directly Drying Process of Sludge: Based on the Multi-index Integrated Assessment Method].

PubMed

Ding, Wen-jie; Chen, Wen-he; Deng, Ming-jia; Luo, Hui; Li, Lin; Liu, Jun-xin

2016-02-15

Co-processing of sewage sludge using the cement kiln can realize sludge harmless treatment, quantity reduction, stabilization and reutilization. The moisture content should be reduced to below 30% to meet the requirement of combustion. Thermal drying is an effective way for sludge desiccation. Odors and volatile organic compounds are generated and released during the sludge drying process, which could lead to odor pollution. The main odor pollutants were selected by the multi-index integrated assessment method. The concentration, olfactory threshold, threshold limit value, smell security level and saturated vapor pressure were considered as indexes based on the related regulations in China and foreign countries. Taking the pollution potential as the evaluation target, and the risk index and odor emission intensity as evaluation indexes, the odor pollution potential rated evaluation model of the pollutants was built according to the Weber-Fechner law. The aim of the present study is to form the rating evaluation method of odor potential pollution capacity suitable for the directly drying process of sludge.

The role of the Drosophila lateral horn in olfactory information processing and behavioral response.

PubMed

Schultzhaus, Janna N; Saleem, Sehresh; Iftikhar, Hina; Carney, Ginger E

2017-04-01

Animals must rapidly and accurately process environmental information to produce the correct behavioral responses. Reactions to previously encountered as well as to novel but biologically important stimuli are equally important, and one understudied region in the insect brain plays a role in processing both types of stimuli. The lateral horn is a higher order processing center that mainly processes olfactory information and is linked via olfactory projection neurons to another higher order learning center, the mushroom body. This review focuses on the lateral horn of Drosophila where most functional studies have been performed. We discuss connectivity between the primary olfactory center, the antennal lobe, and the lateral horn and mushroom body. We also present evidence for the lateral horn playing roles in innate behavioral responses by encoding biological valence to novel odor cues and in learned responses to previously encountered odors by modulating neural activity within the mushroom body. We describe how these processes contribute to acceptance or avoidance of appropriate or inappropriate mates and food, as well as the identification of predators. The lateral horn is a sexually dimorphic and plastic region of the brain that modulates other regions of the brain to ensure that insects produce rapid and effective behavioral responses to both novel and learned stimuli, yet multiple gaps exist in our knowledge of this important center. We anticipate that future studies on olfactory processing, learning, and innate behavioral responses will include the lateral horn in their examinations, leading to a more comprehensive understanding of olfactory information relay and resulting behaviors. Copyright © 2016 Elsevier Ltd. All rights reserved.

In vivo bioelectronic nose using transgenic mice for specific odor detection.

PubMed

Gao, Keqiang; Li, Songmin; Zhuang, Liujing; Qin, Zhen; Zhang, Bin; Huang, Liquan; Wang, Ping

2018-04-15

The olfactory system is a natural biosensor since its peripheral olfactory sensory neurons (OSNs) respond to the external stimuli and transmit the signals to the olfactory bulb (OB) where they are integrated and processed. The axonal connections from the OSNs expressing about 1000 different types of odorant receptors are precisely organized and sorted out onto 1800 glomeruli in the OB, from which the olfactory information is delivered to and perceived by the central nervous system. This process is carried out with particularly high sensitivity, specificity and rapidity, which can be used for explosive detection. Biomimetic olfactory biosensors use various biological components from the olfactory system as sensing elements, possessing great commercial prospects. In this study, we utilized the genetically labeled murine M72 olfactory sensory neurons with the green fluorescent protein (GFP) as sensing components and obtained long-term in vivo electrophysiological recordings from the M72 OSNs by implanting the microelectrode arrays (MEAs) into the behaving mouse's OB. The electrophysiological responses showed high reliability, reproducibility and specificity for odor detection, and particularly, the high sensitivity for the detection of odorants that contain benzene rings. Furthermore, our results indicated that it can detect trinitrotoluene (TNT) in liquid at a concentration as low as 10 -5 M and can distinguish TNT from other chemicals with a similar structure. Thus our study demonstrated that the in vivo biomimetic olfactory system could provide novel approaches to enhancing the specificity and increasing working lifespan of olfactory biosensors capable of detecting explosives. Copyright © 2017 Elsevier B.V. All rights reserved.

An odor flux model for cattle feedlots

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ormerod, R.J.

1994-12-31

Odor nuisance associated with cattle feedlots has been an issue of major interest and concern to regulators, rural communities and the beef industry in Australia over the past decade. Methods of assessing the likely impacts of new feedlots on community odor exposure are still being developed, but in the past few years much has been learnt about the processes of odor generation, flux and dispersion as well as the acceptability of feedlot odor to exposed communities. This paper outlines a model which simulates the complex physical and chemical processes leading to odor emissions in a simple and practical framework. Themore » model, named BULSMEL, has been developed as a response to regulatory requirements for quantitative assessments of odor impact. It will continue to be refined as more data are gathered.« less

Microbial diversity associated with odor modification for production of fertilizers from chicken litter.

PubMed

Enticknap, Julie J; Nonogaki, Hirofumi; Place, Allen R; Hill, Russell T

2006-06-01

Litter from the chicken industry can present several environmental challenges, including offensive odors and runoff into waterways leading to eutrophication. An economically viable solution to the disposal of waste from chicken houses is treatment to produce a natural, granulated fertilizer that can be commercially marketed for garden and commercial use. Odor of the final product is important in consumer acceptance, and an earthy odor is desirable. By understanding and manipulating the microbial processes occurring during this process, it may be possible to modify the odors produced. Geosmin and related volatiles produced by soil actinomycetes are responsible for earthy odors, and actinomycetes are likely to be present in the composting manure. Bacterial communities at each stage of the process were analyzed by culturing studies and denaturing gradient gel electrophoresis (DGGE). The processing steps changed the culturable bacterial community, but the total community was shown by DGGE to be stable throughout the process. A local agricultural soil was analyzed in parallel as a potential source of geosmin-producing actinomycetes. This agricultural soil had higher microbial diversity than the compost at both the culturable and the molecular levels. Actinomycete bacteria were isolated and analyzed by AromaTrax, a gas chromatography-olfactometry system. This system enables the odor production of individual isolates to be monitored, allowing for rational selection of strains for augmentation experiments to improve the odor of the final fertilizer product.

Microbial Diversity Associated with Odor Modification for Production of Fertilizers from Chicken Litter†

PubMed Central

Enticknap, Julie J.; Nonogaki, Hirofumi; Place, Allen R.; Hill, Russell T.

2006-01-01

Litter from the chicken industry can present several environmental challenges, including offensive odors and runoff into waterways leading to eutrophication. An economically viable solution to the disposal of waste from chicken houses is treatment to produce a natural, granulated fertilizer that can be commercially marketed for garden and commercial use. Odor of the final product is important in consumer acceptance, and an earthy odor is desirable. By understanding and manipulating the microbial processes occurring during this process, it may be possible to modify the odors produced. Geosmin and related volatiles produced by soil actinomycetes are responsible for earthy odors, and actinomycetes are likely to be present in the composting manure. Bacterial communities at each stage of the process were analyzed by culturing studies and denaturing gradient gel electrophoresis (DGGE). The processing steps changed the culturable bacterial community, but the total community was shown by DGGE to be stable throughout the process. A local agricultural soil was analyzed in parallel as a potential source of geosmin-producing actinomycetes. This agricultural soil had higher microbial diversity than the compost at both the culturable and the molecular levels. Actinomycete bacteria were isolated and analyzed by AromaTrax, a gas chromatography-olfactometry system. This system enables the odor production of individual isolates to be monitored, allowing for rational selection of strains for augmentation experiments to improve the odor of the final fertilizer product. PMID:16751521

Rapid detection of methanol in artisanal alcoholic beverages

NASA Astrophysics Data System (ADS)

de Goes, R. E.; Muller, M.; Fabris, J. L.

2015-09-01

In the industry of artisanal beverages, uncontrolled production processes may result in contaminated products with methanol, leading to risks for consumers. Owing to the similar odor of methanol and ethanol, as well as their common transparency, the distinction between them is a difficult task. Contamination may also occur deliberately due to the lower price of methanol when compared to ethanol. This paper describes a spectroscopic method for methanol detection in beverages based on Raman scattering and Principal Component Analysis. Associated with a refractometric assessment of the alcohol content, the method may be applied in field for a rapid detection of methanol presence.

Effects of mix ratio, moisture content and aeration rate on sulfur odor emissions during pig manure composting.

PubMed

Zang, Bing; Li, Shuyan; Michel, Frederick; Li, Guoxue; Luo, Yuan; Zhang, Difang; Li, Yangyang

2016-10-01

Sulfur compounds in swine manure can cause odor emissions during composting if conditions are not conducive to their rapid oxidation and degradation. In this study, the effects of controllable composting process variables on sulfur odor emissions were investigated. These included pig manure to corn stalk mix ratio (0.7:1, 1.5:1 and 2.2:1dw basis), initial moisture content (60%, 65%, 70% and 75%) and aeration rate (1.0, 2.0, 3.0 and 4.0m(3)m(-3)h(-1)). The compounds measured were carbonyl sulfide, carbon disulfide, hydrogen sulfide, methyl mercaptan, ethyl mercaptan, diethyl sulfide, dimethyl sulfide (Me2S) and dimethyl disulfide (Me2SS). The results showed that total sulfur losses ranged from 3.9% to 18.3% after 26days of composting. Me2S and Me2SS were the primary (>59.61%) sulfur compounds released during this period. After turning, emission rates of both Me2S and Me2SS increased. Emissions of the other six sulfur compounds were low and inconsistent during composting. Within the compost, feedstock mix ratio significantly influenced the concentration of Me2SS, while aeration rate significantly affected Me2S concentration (p<0.05). Moisture content did not have a significant effect on the concentrations of either of these two compounds. Concentrations of sulfur odor compounds were the lowest at the highest aeration rate. Therefore, high aeration rates during the thermophilic phase, especially after turning, are recommended to minimize sulfur odors produced during swine manure composting. Copyright © 2016 Elsevier Ltd. All rights reserved.

Lesions that functionally disconnect the anterior and posterodorsal sub-regions of the medial amygdala eliminate opposite-sex odor preference in male Syrian hamsters (Mesocricetus auratus)

PubMed Central

Maras, Pamela M.; Petrulis, Aras

2009-01-01

In many rodent species, such as Syrian hamsters, reproductive behavior requires neural integration of chemosensory information and steroid hormone cues. The medial amygdala processes both of these signals through anatomically distinct sub-regions; the anterior region (MeA) receives substantial chemosensory input, but contains few steroid receptor-labeled neurons, whereas the posterodorsal region (MePD) receives less chemosensory input, but contains a dense population of steroid receptors. Importantly, these sub-regions have considerable reciprocal connections, and the goal of this experiment was therefore to determine whether interactions between MeA and MePD are required for male hamsters’ preference to investigate female over male odors. To functionally disconnect MeA and MePD, males received unilateral lesions of MeA and MePD within opposite brain hemispheres. Control males received either unilateral lesions of MeA and MePD within the same hemisphere or sham surgery. Odor preferences were measured using a 3-choice apparatus, which simultaneously presented female, male and clean odor stimuli; all tests were done under conditions that either prevented or allowed contact with the odor sources. Under non-contact conditions, males with asymmetrical lesions investigated female and male odors equally, whereas males in both control groups preferred to investigate female odors. Under contact conditions, all groups investigated female odors longer than male odors, although males with asymmetrical lesions displayed decreased investigation of female odors compared to sham males. These data suggest that MeA-MePD interactions are critical for processing primarily the volatile components of social odors and highlight the importance of input from the main olfactory system to these nuclei in the regulation of reproductive behavior. More broadly, these results support the role of the medial amygdala in integrating chemosensory and hormone information, a process that may underlie social odor processing in a variety of behavioral contexts. PMID:19931356

Right Occipital Cortex Activation Correlates with Superior Odor Processing Performance in the Early Blind

PubMed Central

Grandin, Cécile B.; Dricot, Laurence; Plaza, Paula; Lerens, Elodie; Rombaux, Philippe; De Volder, Anne G.

2013-01-01

Using functional magnetic resonance imaging (fMRI) in ten early blind humans, we found robust occipital activation during two odor-processing tasks (discrimination or categorization of fruit and flower odors), as well as during control auditory-verbal conditions (discrimination or categorization of fruit and flower names). We also found evidence for reorganization and specialization of the ventral part of the occipital cortex, with dissociation according to stimulus modality: the right fusiform gyrus was most activated during olfactory conditions while part of the left ventral lateral occipital complex showed a preference for auditory-verbal processing. Only little occipital activation was found in sighted subjects, but the same right-olfactory/left-auditory-verbal hemispheric lateralization was found overall in their brain. This difference between the groups was mirrored by superior performance of the blind in various odor-processing tasks. Moreover, the level of right fusiform gyrus activation during the olfactory conditions was highly correlated with individual scores in a variety of odor recognition tests, indicating that the additional occipital activation may play a functional role in odor processing. PMID:23967263

Diagnostic Value of the Impairment of Olfaction in Parkinson's Disease

PubMed Central

Casjens, Swaantje; Eckert, Angelika; Woitalla, Dirk; Ellrichmann, Gisa; Turewicz, Michael; Stephan, Christian; Eisenacher, Martin; May, Caroline; Meyer, Helmut E.; Brüning, Thomas; Pesch, Beate

2013-01-01

Background Olfactory impairment is increasingly recognized as an early symptom in the development of Parkinson's disease. Testing olfactory function is a non-invasive method but can be time-consuming which restricts its application in clinical settings and epidemiological studies. Here, we investigate odor identification as a supportive diagnostic tool for Parkinson's disease and estimate the performance of odor subsets to allow a more rapid testing of olfactory impairment. Methodology/Principal Findings Odor identification was assessed with 16 Sniffin' sticks in 148 Parkinson patients and 148 healthy controls. Risks of olfactory impairment were estimated with proportional odds models. Random forests were applied to classify Parkinson and non-Parkinson patients. Parkinson patients were rarely normosmic (identification of more than 12 odors; 16.8%) and identified on average seven odors whereas the reference group identified 12 odors and showed a higher prevalence of normosmy (31.1%). Parkinson patients with rigidity dominance had a twofold greater prevalence of olfactory impairment. Disease severity was associated with impairment of odor identification (per score point of the Hoehn and Yahr rating OR 1.87, 95% CI 1.26–2.77). Age-related impairment of olfaction showed a steeper gradient in Parkinson patients. Coffee, peppermint, and anise showed the largest difference in odor identification between Parkinson patients and controls. Random forests estimated a misclassification rate of 22.4% when comparing Parkinson patients with healthy controls using all 16 odors. A similar rate (23.8%) was observed when only the three aforementioned odors were applied. Conclusions/Significance Our findings indicate that testing odor identification can be a supportive diagnostic tool for Parkinson's disease. The application of only three odors performed well in discriminating Parkinson patients from controls, which can facilitate a wider application of this method as a point-of-care test. PMID:23696904

Altered olfactory processing of stress-related body odors and artificial odors in patients with panic disorder.

PubMed

Wintermann, Gloria-Beatrice; Donix, Markus; Joraschky, Peter; Gerber, Johannes; Petrowski, Katja

2013-01-01

Patients with Panic Disorder (PD) direct their attention towards potential threat, followed by panic attacks, and increased sweat production. Onés own anxiety sweat odor influences the attentional focus, and discrimination of threat or non-threat. Since olfactory projection areas overlap with neuronal areas of a panic-specific fear network, the present study investigated the neuronal processing of odors in general and of stress-related sweat odors in particular in patients with PD. A sample of 13 patients with PD with/ without agoraphobia and 13 age- and gender-matched healthy controls underwent an fMRI investigation during olfactory stimulation with their stress-related sweat odors (TSST, ergometry) as well as artificial odors (peach, artificial sweat) as non-fearful non-body odors. The two groups did not differ with respect to their olfactory identification ability. Independent of the kind of odor, the patients with PD showed activations in fronto-cortical areas in contrast to the healthy controls who showed activations in olfaction-related areas such as the amygdalae and the hippocampus. For artificial odors, the patients with PD showed a decreased neuronal activation of the thalamus, the posterior cingulate cortex and the anterior cingulate cortex. Under the presentation of sweat odor caused by ergometric exercise, the patients with PD showed an increased activation in the superior temporal gyrus, the supramarginal gyrus, and the cingulate cortex which was positively correlated with the severity of the psychopathology. For the sweat odor from the anxiety condition, the patients with PD showed an increased activation in the gyrus frontalis inferior, which was positively correlated with the severity of the psychopathology. The results suggest altered neuronal processing of olfactory stimuli in PD. Both artificial odors and stress-related body odors activate specific parts of a fear-network which is associated with an increased severity of the psychopathology.

Left Posterior Orbitofrontal Cortex Is Associated With Odor-Induced Autobiographical Memory: An fMRI Study.

PubMed

Watanabe, Keiko; Masaoka, Yuri; Kawamura, Mitsuru; Yoshida, Masaki; Koiwa, Nobuyoshi; Yoshikawa, Akira; Kubota, Satomi; Ida, Masahiro; Ono, Kenjiro; Izumizaki, Masahiko

2018-01-01

Autobiographical odor memory (AM-odor) accompanied by a sense of realism of a specific memory elicits strong emotions. AM-odor differs from memory triggered by other sensory modalities, possibly because olfaction involves a unique sensory process. Here, we examined the orbitofrontal cortex (OFC), using functional magnetic resonance imaging (fMRI) to determine which OFC subregions are related to AM-odor. Both AM-odor and a control odor successively increased subjective ratings of comfortableness and pleasantness. Importantly, AM-odor also increased arousal levels and the vividness of memories, and was associated with a deep and slow breathing pattern. fMRI analysis indicated robust activation in the left posterior OFC (L-POFC). Connectivity between the POFC and whole brain regions was estimated using psychophysiological interaction analysis (PPI). We detected several trends in connectivity between L-POFC and bilateral precuneus, bilateral rostral dorsal anterior cingulate cortex (rdACC), and left parahippocampus, which will be useful for targeting our hypotheses for future investigations. The slow breathing observed in AM-odor was correlated with rdACC activation. Odor associated with emotionally significant autobiographical memories was accompanied by slow and deep breathing, possibly involving rdACC processing.

CONTROLLING ODOROUS EMISSIONS FROM IRON FOUNDRIES

EPA Science Inventory

The report discusses the control of odorous emissions from iron foundries. he main process sources of odors in iron foundries are mold and core making, casting, and sand shakeout. he odors are usually caused by chemicals, which may be present as binders and other additives to the...

Identification and characterization of odorous gas emission from a full-scale food waste anaerobic digestion plant in China.

PubMed

Kong, Xin; Liu, Jianguo; Ren, Lianhai; Song, Minying; Wang, Xiaowei; Ni, Zhe; Nie, Xiaoqin

2015-10-01

Odorous gas emission characteristic along with the successive processes of a typical full-scale food waste (FW) anaerobic digestion plant in China was investigated in September and January. Seasonal variations in pollutant concentration and principal component analysis (PCA) showed markedly different characteristics between the two months. However, the main reason for the seasonal difference at the sorting process differed from the reason for the seasonal difference at other treatment units. Most odorous volatile organic compound (VOC) concentrations tested near an anaerobic digestion tank were similar and low in both months. Odor indices, including odor contribution (OC) and odor activity value (OAV) of various odorants, were further calculated to evaluate the malodor degree and contribution to the nuisance smell of any odorant. Brought about by people's different dietary habits, H2S and sulfocompounds were found to be dominant contributors to the large total OVA in the January test. By contrast, oxygenated organic compounds played an important role on the sum of OVA in September.

Parallel processing via a dual olfactory pathway in the honeybee.

PubMed

Brill, Martin F; Rosenbaum, Tobias; Reus, Isabelle; Kleineidam, Christoph J; Nawrot, Martin P; Rössler, Wolfgang

2013-02-06

In their natural environment, animals face complex and highly dynamic olfactory input. Thus vertebrates as well as invertebrates require fast and reliable processing of olfactory information. Parallel processing has been shown to improve processing speed and power in other sensory systems and is characterized by extraction of different stimulus parameters along parallel sensory information streams. Honeybees possess an elaborate olfactory system with unique neuronal architecture: a dual olfactory pathway comprising a medial projection-neuron (PN) antennal lobe (AL) protocerebral output tract (m-APT) and a lateral PN AL output tract (l-APT) connecting the olfactory lobes with higher-order brain centers. We asked whether this neuronal architecture serves parallel processing and employed a novel technique for simultaneous multiunit recordings from both tracts. The results revealed response profiles from a high number of PNs of both tracts to floral, pheromonal, and biologically relevant odor mixtures tested over multiple trials. PNs from both tracts responded to all tested odors, but with different characteristics indicating parallel processing of similar odors. Both PN tracts were activated by widely overlapping response profiles, which is a requirement for parallel processing. The l-APT PNs had broad response profiles suggesting generalized coding properties, whereas the responses of m-APT PNs were comparatively weaker and less frequent, indicating higher odor specificity. Comparison of response latencies within and across tracts revealed odor-dependent latencies. We suggest that parallel processing via the honeybee dual olfactory pathway provides enhanced odor processing capabilities serving sophisticated odor perception and olfactory demands associated with a complex olfactory world of this social insect.

A Robot Equipped with a High-Speed LSPR Gas Sensor Module for Collecting Spatial Odor Information from On-Ground Invisible Odor Sources.

PubMed

Yang, Zhongyuan; Sassa, Fumihiro; Hayashi, Kenshi

2018-06-22

Improving the efficiency of detecting the spatial distribution of gas information with a mobile robot is a great challenge that requires rapid sample collection, which is basically determined by the speed of operation of gas sensors. The present work developed a robot equipped with a high-speed gas sensor module based on localized surface plasmon resonance. The sensor module is designed to sample gases from an on-ground odor source, such as a footprint material or artificial odor marker, via a fine sampling tubing. The tip of the sampling tubing was placed close to the ground to reduce the sampling time and the effect of natural gas diffusion. On-ground ethanol odor sources were detected by the robot at high resolution (i.e., 2.5 cm when the robot moved at 10 cm/s), and the reading of gas information was demonstrated experimentally. This work may help in the development of environmental sensing robots, such as the development of odor source mapping and multirobot systems with pheromone tracing.

A unique memory process modulated by emotion underpins successful odor recognition and episodic retrieval in humans

PubMed Central

Saive, Anne-Lise; Royet, Jean-Pierre; Ravel, Nadine; Thévenet, Marc; Garcia, Samuel; Plailly, Jane

2014-01-01

We behaviorally explore the link between olfaction, emotion and memory by testing the hypothesis that the emotion carried by odors facilitates the memory of specific unique events. To investigate this idea, we used a novel behavioral approach inspired by a paradigm developed by our team to study episodic memory in a controlled and as ecological as possible way in humans. The participants freely explored three unique and rich laboratory episodes; each episode consisted of three unfamiliar odors (What) positioned at three specific locations (Where) within a visual context (Which context). During the retrieval test, which occurred 24–72 h after the encoding, odors were used to trigger the retrieval of the complex episodes. The participants were proficient in recognizing the target odors among distractors and retrieving the visuospatial context in which they were encountered. The episodic nature of the task generated high and stable memory performances, which were accompanied by faster responses and slower and deeper breathing. Successful odor recognition and episodic memory were not related to differences in odor investigation at encoding. However, memory performances were influenced by the emotional content of the odors, regardless of odor valence, with both pleasant and unpleasant odors generating higher recognition and episodic retrieval than neutral odors. Finally, the present study also suggested that when the binding between the odors and the spatio-contextual features of the episode was successful, the odor recognition and the episodic retrieval collapsed into a unique memory process that began as soon as the participants smelled the odors. PMID:24936176

Mixture and odorant processing in the olfactory systems of insects: a comparative perspective.

PubMed

Clifford, Marie R; Riffell, Jeffrey A

2013-11-01

Natural olfactory stimuli are often complex mixtures of volatiles, of which the identities and ratios of constituents are important for odor-mediated behaviors. Despite this importance, the mechanism by which the olfactory system processes this complex information remains an area of active study. In this review, we describe recent progress in how odorants and mixtures are processed in the brain of insects. We use a comparative approach toward contrasting olfactory coding and the behavioral efficacy of mixtures in different insect species, and organize these topics around four sections: (1) Examples of the behavioral efficacy of odor mixtures and the olfactory environment; (2) mixture processing in the periphery; (3) mixture coding in the antennal lobe; and (4) evolutionary implications and adaptations for olfactory processing. We also include pertinent background information about the processing of individual odorants and comparative differences in wiring and anatomy, as these topics have been richly investigated and inform the processing of mixtures in the insect olfactory system. Finally, we describe exciting studies that have begun to elucidate the role of the processing of complex olfactory information in evolution and speciation.

Ventilation requirements for control of occupancy odor and tobacco smoke odor: laboratory studies. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cain, W.S.; Isseroff, R.; Leaderer, B.P.

1981-04-01

Experiments on occupancy odor addressed the question of why required ventilation rate per occupant increased progressively with increases in the number of persons in a space. In order to investigate ventilation requirements under approximately ideal conditions, we constructed an aluminum-lined environmental chamber with excellent control over environmental conditions and a ventilation system that provided rapid and uniform mixing of air. Psychophysical experiments on occupancy odor explored 47 different combinations of occupancy density, temperature and humidity, and ventilation rate. The experiments collected judgements both from visitors, who smelled air from the chamber only once every few minutes, and from occupants, whomore » remained in the chamber for an hour at a time. The judgements of visitors revealed that occupancy odor increased only gradually over time and rarely reached very high or objectionable levels. Judgements of occupants also revealed rather minor dissatisfaction. Only during combinations of high temperature and humidity did objectionability become more than a minor issue to either group. Experiments on cigarette smoking explored rates of 4, 8, and 16 cigarettes per hour under various environmental conditions and with ventilation rates as high as 68 cfm (34 L.s/sup -1/) per occupant. As soon as occupants lit cigarettes in the chamber, the odor level increased dramatically. At ventilation rates far greater than necessary to control occupancy odor, the odor from cigarette smoking remained quite intense. In general, the odor proved impossible to control adequately even with a ventilation rate of 68 cfm (34 L.s/sup -1/) per occupant (4 occupants) and even when only one occupant smoked at a time. As in the case of occupancy odor, a combination of high temperature and humidity exacerbated the odor problem.« less

Application of PTR-MS for Measuring Odorant Emissions from Soil Application of Manure Slurry

PubMed Central

Feilberg, Anders; Bildsoe, Pernille; Nyord, Tavs

2015-01-01

Odorous volatile organic compounds (VOC) and hydrogen sulfide (H2S) are emitted together with ammonia (NH3) from manure slurry applied as a fertilizer, but little is known about the composition and temporal variation of the emissions. In this work, a laboratory method based on dynamic flux chambers packed with soil has been used to measure emissions from untreated pig slurry and slurry treated by solid-liquid separation and ozonation. Proton-transfer-reaction mass spectrometry (PTR-MS) was used to provide time resolved data for a range of VOC, NH3 and H2S. VOC included organic sulfur compounds, carboxylic acids, phenols, indoles, alcohols, ketones and aldehydes. H2S emission was remarkably observed to take place only in the initial minutes after slurry application, which is explained by its high partitioning into the air phase. Long-term odor effects are therefore assessed to be mainly due to other volatile compounds with low odor threshold values, such as 4-methylphenol. PTR-MS signal assignment was verified by comparison to a photo-acoustic analyzer (NH3) and to thermal desorption GC/MS (VOC). Due to initial rapid changes in odorant emissions and low concentrations of odorants, PTR-MS is assessed to be a very useful method for assessing odor following field application of slurry. The effects of treatments on odorant emissions are discussed. PMID:25585103

Central insulin administration improves odor-cued reactivation of spatial memory in young men.

PubMed

Brünner, Yvonne F; Kofoet, Anja; Benedict, Christian; Freiherr, Jessica

2015-01-01

Insulin receptors are ubiquitously found in the human brain, comprising the olfactory bulb, essential for odor processing, and the hippocampus, important for spatial memory processing. The present study aimed at examining if intranasal insulin, which is known to transiently increase brain insulin levels in humans, would improve odor-cued reactivation of spatial memory in young men. We applied a double-blind, placebo-controlled, counterbalanced within-subject design. The study was conducted at the research unit of a university hospital. Interventions/Participants/Main Outcome Measures: Following intranasal administration of either insulin (40 I.U.) or placebo, male subjects (n = 18) were exposed to eight odors. During each odor exposure, a green-colored field was presented on a 17-in. computer screen. During immediate recall (comprising 3 runs), the participants were re-exposed to each odor cue, and were asked to select the corresponding field (with visual feedback after each response). The delayed recall was scheduled ∼10 min later (without feedback). To test if insulin's putative effect on odor-place memory would be domain-specific, participants also performed a separate place and odor recognition task. Intranasal insulin improved the delayed but not immediate odor-cued recall of spatial memory. This effect was independent of odor type and in the absence of systemic side effects (eg, fasting plasma glucose levels remained unaltered). Place and odor recognition were unaffected by the insulin treatment. These findings suggest that acute intranasal insulin improves odor-cued reactivation of spatial memory in young men.

Do Valenced Odors and Trait Body Odor Disgust Affect Evaluation of Emotion in Dynamic Faces?

PubMed

Syrjänen, Elmeri; Liuzza, Marco Tullio; Fischer, Håkan; Olofsson, Jonas K

2017-12-01

Disgust is a core emotion evolved to detect and avoid the ingestion of poisonous food as well as the contact with pathogens and other harmful agents. Previous research has shown that multisensory presentation of olfactory and visual information may strengthen the processing of disgust-relevant information. However, it is not known whether these findings extend to dynamic facial stimuli that changes from neutral to emotionally expressive, or if individual differences in trait body odor disgust may influence the processing of disgust-related information. In this preregistered study, we tested whether a classification of dynamic facial expressions as happy or disgusted, and an emotional evaluation of these facial expressions, would be affected by individual differences in body odor disgust sensitivity, and by exposure to a sweat-like, negatively valenced odor (valeric acid), as compared with a soap-like, positively valenced odor (lilac essence) or a no-odor control. Using Bayesian hypothesis testing, we found evidence that odors do not affect recognition of emotion in dynamic faces even when body odor disgust sensitivity was used as moderator. However, an exploratory analysis suggested that an unpleasant odor context may cause faster RTs for faces, independent of their emotional expression. Our results further our understanding of the scope and limits of odor effects on facial perception affect and suggest further studies should focus on reproducibility, specifying experimental circumstances where odor effects on facial expressions may be present versus absent.

Olfactory receptor neurons use gain control and complementary kinetics to encode intermittent odorant stimuli

PubMed Central

Gorur-Shandilya, Srinivas; Demir, Mahmut; Long, Junjiajia; Clark, Damon A; Emonet, Thierry

2017-01-01

Insects find food and mates by navigating odorant plumes that can be highly intermittent, with intensities and durations that vary rapidly over orders of magnitude. Much is known about olfactory responses to pulses and steps, but it remains unclear how olfactory receptor neurons (ORNs) detect the intensity and timing of natural stimuli, where the absence of scale in the signal makes detection a formidable olfactory task. By stimulating Drosophila ORNs in vivo with naturalistic and Gaussian stimuli, we show that ORNs adapt to stimulus mean and variance, and that adaptation and saturation contribute to naturalistic sensing. Mean-dependent gain control followed the Weber-Fechner relation and occurred primarily at odor transduction, while variance-dependent gain control occurred at both transduction and spiking. Transduction and spike generation possessed complementary kinetic properties, that together preserved the timing of odorant encounters in ORN spiking, regardless of intensity. Such scale-invariance could be critical during odor plume navigation. DOI: http://dx.doi.org/10.7554/eLife.27670.001 PMID:28653907

Odor-induced recall of emotional memories in PTSD-Review and new paradigm for research.

PubMed

Daniels, Judith K; Vermetten, Eric

2016-10-01

It is clinically well known that olfactory intrusions in PTSD can be a disabling phenomena due to the involuntary recall of odor memories. Odorants can trigger involuntary recall of emotional memories as well have the potential to help diminishing emotional arousal as grounding stimuli. Despite major advances in our understanding of the function of olfactory system, the study of the relation of olfaction and emotional memory is still relatively scarce. Odor memory is long thought to be different than other types of memories such as verbal or visual memories, being more strongly engraved and more closely related to strong emotions. Brain areas mediating smell memory including orbitofrontal cortex and other parts of medial prefrontal cortex, hippocampus and amygdala, have been implicated in learning and memory and are part of a neural circuitry that is involved in PTSD. The olfactory cortex itself also plays an important role in emotional processing. Clinical observations support the notion that odor-evoked memories can play a role in the symptomatology of PTSD. This paper reviews a re-emerging body of science linking odor processing to emotional processing in PTSD using the calming and grounding effect of odors as well as the use of odors in augmented exposure therapy. This results in converging evidence that olfaction is an excellent model for studying many questions germane to the field of human emotional memory processing. Copyright © 2016 Elsevier Inc. All rights reserved.

Immunotoxic cholinergic lesions in the basal forebrain reverse the effects of entorhinal cortex lesions on conditioned odor aversion in the rat.

PubMed

Ferry, Barbara; Herbeaux, Karin; Cosquer, Brigitte; Traissard, Natalia; Galani, Rodrigue; Cassel, Jean-Christophe

2007-07-01

Conditioned odor aversion (COA) corresponds to the avoidance of an odorized-tasteless solution (conditioned stimulus, CS) previously paired with toxicosis. COA occurs only when the interstimulus interval (ISI) is kept short, suggesting that the memory trace of the odor is subject to rapid decay. Previous experiments have shown that the entorhinal cortex (EC) is involved in the acquisition of COA, since lesion of the EC rendered COA tolerant to long ISI. Because EC lesions induce a septo-hippocampal cholinergic sprouting, the present experiment investigated whether COA tolerance to long ISI may be linked to this sprouting reaction. In a first experiment, male Long-Evans rats subjected to bilateral excitotoxic EC lesions combined to intracerebroventricular infusions of the selective cholinergic immunotoxin 192 IgG-saporin were exposed to odor-toxicosis pairing using a long ISI (120 min). Results showed that EC-lesioned rats displayed COA with the long ISI but not the control groups. In rats with EC combined to 192 IgG-saporin lesions, histological analysis demonstrated no evidence for cholinergic septo-hippocampal sprouting. In a second experiment, animals with 192-IgG saporin lesion showed a marked COA with a short ISI (5 min). These results suggest that the COA with the long ISI found in rats with EC lesions might involve a functional activity related to the EC lesion-induced hippocampal cholinergic sprouting. As the injection of 192 IgG-saporin alone did not affect COA with a short ISI, our data also point to a possible role of hippocampal cholinergic neurons in the modulation of memory processes underlying COA.

Evidence of conscious and subconscious olfactory information processing during word encoding: a magnetoencephalographic (MEG) study.

PubMed

Walla, Peter; Hufnagl, Bernd; Lehrner, Johann; Mayer, Dagmar; Lindinger, Gerald; Deecke, Lüder; Lang, Wilfried

2002-11-01

The present study was meant to distinguish between unconscious and conscious olfactory information processing and to investigate the influence of olfaction on word information processing. Magnetic field changes were recorded in healthy young participants during deep encoding of visually presented words whereby some of the words were randomly associated with an odor. All recorded data were then split into two groups. One group consisted of participants who did not consciously perceive the odor during the whole experiment whereas the other group did report continuous conscious odor perception. The magnetic field changes related to the condition 'words without odor' were subtracted from the magnetic field changes related to the condition 'words with odor' for both groups. First, an odor-induced effect occurred between about 200 and 500 ms after stimulus onset which was similar in both groups. It is interpreted to reflect an activity reduction during word encoding related to the additional olfactory stimulation. Second, a later effect occurred between about 600 and 900 ms after stimulus onset which differed between the two groups. This effect was due to higher brain activity related to the additional olfactory stimulation. It was more pronounced in the group consisting of participants who consciously perceived the odor during the whole experiment as compared to the other group. These results are interpreted as evidence that the later effect is related to conscious odor perception whereas the earlier effect reflects unconscious olfactory information processing. Furthermore, our study provides evidence that only the conscious perception of an odor which is simultaneously presented to the visual presentation of a word reduces its chance to be subsequently recognized.

Rabbit Neonates and Human Adults Perceive a Blending 6-Component Odor Mixture in a Comparable Manner

PubMed Central

Sinding, Charlotte; Thomas-Danguin, Thierry; Chambault, Adeline; Béno, Noelle; Dosne, Thibaut; Chabanet, Claire; Schaal, Benoist; Coureaud, Gérard

2013-01-01

Young and adult mammals are constantly exposed to chemically complex stimuli. The olfactory system allows for a dual processing of relevant information from the environment either as single odorants in mixtures (elemental perception) or as mixtures of odorants as a whole (configural perception). However, it seems that human adults have certain limits in elemental perception of odor mixtures, as suggested by their inability to identify each odorant in mixtures of more than 4 components. Here, we explored some of these limits by evaluating the perception of three 6-odorant mixtures in human adults and newborn rabbits. Using free-sorting tasks in humans, we investigated the configural or elemental perception of these mixtures, or of 5-component sub-mixtures, or of the 6-odorant mixtures with modified odorants' proportion. In rabbit pups, the perception of the same mixtures was evaluated by measuring the orocephalic sucking response to the mixtures or their components after conditioning to one of these stimuli. The results revealed that one mixture, previously shown to carry the specific odor of red cordial in humans, was indeed configurally processed in humans and in rabbits while the two other 6-component mixtures were not. Moreover, in both species, such configural perception was specific not only to the 6 odorants included in the mixture but also to their respective proportion. Interestingly, rabbit neonates also responded to each odorant after conditioning to the red cordial mixture, which demonstrates their ability to perceive elements in addition to configuration in this complex mixture. Taken together, the results provide new insights related to the processing of relatively complex odor mixtures in mammals and the inter-species conservation of certain perceptual mechanisms; the results also revealed some differences in the expression of these capacities between species putatively linked to developmental and ecological constraints. PMID:23341948

Mammalian Odor Information Recognition by Implanted Microsensor Array in vivo

NASA Astrophysics Data System (ADS)

Zhou, Jun; Dong, Qi; Zhuang, Liujing; Liu, Qingjun; Wang, Ping

2011-09-01

The mammalian olfactory system has an exquisite capacity to rapidly recognize and discriminate thousands of distinct odors in our environment. Our research group focus on reading information from olfactory bulb circuit of anethetized Sprague-Dawley rat and utilize artificial recognition system for odor discrimination. After being stimulated by three odors with concentration of 10 μM to rat nose, the response of mitral cells in olfactory bulb is recorded by eight channel microwire sensor array. In 20 sessions with 3 animals, we obtained 30 discriminated individual cells recordings. The average firing rates of the cells are Isoamyl acetate 26 Hz, Methoxybenzene 16 Hz, and Rose essential oil 11 Hz. By spike sorting, we detect peaks and analyze the interspike interval distribution. Further more, principal component analysis is applied to reduce the dimensionality of the data sets and classify the response.

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

Free flight odor tracking in Drosophila: Effect of wing chemosensors, sex and pheromonal gene regulation

PubMed Central

Houot, Benjamin; Gigot, Vincent; Robichon, Alain; Ferveur, Jean-François

2017-01-01

The evolution of powered flight in insects had major consequences for global biodiversity and involved the acquisition of adaptive processes allowing individuals to disperse to new ecological niches. Flies use both vision and olfactory input from their antennae to guide their flight; chemosensors on fly wings have been described, but their function remains mysterious. We studied Drosophila flight in a wind tunnel. By genetically manipulating wing chemosensors, we show that these structures play an essential role in flight performance with a sex-specific effect. Pheromonal systems are also involved in Drosophila flight guidance: transgenic expression of the pheromone production and detection gene, desat1, produced low, rapid flight that was absent in control flies. Our study suggests that the sex-specific modulation of free-flight odor tracking depends on gene expression in various fly tissues including wings and pheromonal-related tissues. PMID:28067325

[Perception of odor quality by Free Image-Association Test].

PubMed

Ueno, Y

1992-10-01

A method was devised for evaluating odor quality. Subjects were requested to freely describe the images elicited by smelling odors. This test was named the "Free Image-Association Test (FIT)". The test was applied for 20 flavors of various foods, five odors from the standards of T&T olfactometer (Japanese standard olfactory test), butter of yak milk, and incense from Lamaism temples. The words for expressing imagery were analyzed by multidimensional scaling and cluster analysis. Seven clusters of odors were obtained. The feature of these clusters were quite similar to that of primary odors which have been suggested by previous studies. However, the clustering of odors can not be explained on the basis of the primary-odor theory, but the information processing theory originally proposed by Miller (1956). These results support the usefulness of the Free Image-Association Test for investigating odor perception based on the images associated with odors.

Discriminating the stimulus elements during human odor-taste learning: a successful analytic stance does not eliminate learning.

PubMed

Stevenson, Richard J; Mahmut, Mehmet K

2011-10-01

Odor "sweetness" may arise from experiencing odors and tastes together, resulting in a flavor memory that is later reaccessed by the odor. Forming a flavor memory may be impaired if the taste and odor elements are apparent during exposure, suggesting that configural processing may underpin learning. Using a new procedure, participants made actual flavor discriminations for one odor-taste pair (e.g., Taste A vs. Odor X-Taste A) and mock discriminations for another (e.g., Odor Y-Taste B vs. Odor Y-Taste B). Participants, who were successful at detecting the actual flavor discriminations, demonstrated equal amounts of learning for both odor-taste pairings. These results suggest that although a capacity to discriminate flavor into its elements may be necessary to support learning, whether participants experience a configural or elemental flavor representation may not.

Treatment of taste and odor causing compounds 2-methyl isoborneol and geosmin in drinking water: a critical review.

PubMed

Srinivasan, Rangesh; Sorial, George A

2011-01-01

Problems due to the taste and odor in drinking water are common in treatment facilities around the world. Taste and odor are perceived by the public as the primary indicators of the safely and acceptability of drinking water and are mainly caused by the presence of two semi-volatile compounds--2-methyl isoborneol (MIB) and geosmin. A review of these two taste and odor causing compounds in drinking water is presented. The sources for the formation of these compounds in water are discussed along with the health and regulatory implications. The recent developments in the analysis of MIB/geosmin in water which have allowed for rapid measurements in the nanogram per liter concentrations are also discussed. This review focuses on the relevant treatment alternatives, that are described in detail with emphasis on their respective advantages and problems associated with their implementation in a full-scale facility. Conventional treatment processes in water treatment plants, such as coagulation, sedimentation and chlorination have been found to be ineffective for removal of MIB/geosmin. Studies have shown powdered activated carbon, ozonation and biofiltration to be effective in treatment of these two compounds. Although some of these technologies are more effective and show more promise than the others, much work remains to be done to optimize these technologies so that they can be retrofitted or installed with minimal impact on the overall operation and effectiveness of the treatment system.

Off-flavor related volatiles in soymilk as affected by soybean variety, grinding, and heat-processing methods.

PubMed

Zhang, Yan; Guo, Shuntang; Liu, Zhisheng; Chang, Sam K C

2012-08-01

Off-flavor of soymilk is a barrier to the acceptance of consumers. The objectionable soy odor can be reduced through inhibition of their formation or through removal after being formed. In this study, soymilk was prepared by three grinding methods (ambient, cold, and hot grinding) from two varieties (yellow Prosoy and a black soybean) before undergoing three heating processes: stove cooking, one-phase UHT (ultrahigh temperature), and two-phase UHT process using a Microthermics direct injection processor, which was equipped with a vacuuming step to remove injected water and volatiles. Eight typical soy odor compounds, generated from lipid oxidation, were extracted by a solid-phase microextraction method and analyzed by gas chromatography. The results showed that hot grinding and cold grinding significantly reduced off-flavor as compared with ambient grinding, and hot grinding achieved the best result. The UHT methods, especially the two-phase UHT method, were effective to reduce soy odor. Different odor compounds showed distinct concentration patterns because of different formation mechanisms. The two varieties behaved differently in odor formation during the soymilk-making process. Most odor compounds could be reduced to below the detection limit through a combination of hot grinding and two-phase UHT processing. However, hot grinding gave lower solid and protein recoveries in soymilk.

Selective attention to affective value alters how the brain processes olfactory stimuli.

PubMed

Rolls, Edmund T; Grabenhorst, Fabian; Margot, Christian; da Silva, Maria A A P; Velazco, Maria Ines

2008-10-01

How does selective attention to affect influence sensory processing? In a functional magnetic resonance imaging investigation, when subjects were instructed to remember and rate the pleasantness of a jasmine odor, activations were greater in the medial orbito-frontal and pregenual cingulate cortex than when subjects were instructed to remember and rate the intensity of the odor. When the subjects were instructed to remember and rate the intensity, activations were greater in the inferior frontal gyrus. These top-down effects occurred not only during odor delivery but started in a preparation period after the instruction before odor delivery, and continued after termination of the odor in a short-term memory period. Thus, depending on the context in which odors are presented and whether affect is relevant, the brain prepares itself, responds to, and remembers an odor differently. These findings show that when attention is paid to affective value, the brain systems engaged to prepare for, represent, and remember a sensory stimulus are different from those engaged when attention is directed to the physical properties of a stimulus such as its intensity. This differential biasing of brain regions engaged in processing a sensory stimulus depending on whether the cognitive demand is for affect-related versus more sensory-related processing may be an important aspect of cognition and attention. This has many implications for understanding the effects not only of olfactory but also of other sensory stimuli.

Swimming in an Unsteady World

NASA Astrophysics Data System (ADS)

Koehl, M. A. R.

2016-02-01

When animals swim in marine habitats, the water through which they move is usually flowing. Therefore, an important part of understanding the physics of how animals swim in nature is determining how they interact with the fluctuating turbulent water currents in their environment. The research systems we have been using to address this question are microscopic marine animals swimming in turbulent, wavy water flow over spatially-complex communities of organisms growing on surfaces. Field measurements of water motion were used to design realistic turbulent flow in a laboratory wave-flume over different substrata, particle-image velocimetry was used to measure fine-scale, rapidly-varying water velocity vector fields, and planar laser-induced fluorescence was used to measure concentrations of chemical cues from the substratum. We used individual-based models of small animals swimming in this unsteady flow to determine how their trajectories and contacts with substrata were affected by their locomotion through the water, rotation by local shear, response to odors, and transport by ambient flow. We found that the shears, accelerations, and odor concentrations encountered by small swimmers fluctuate rapidly, with peaks much higher than mean values lasting fractions of a second. We identified ways in which the behavior of small, weak swimmers can bias how they are transported by ambient flow (e.g. sinking during brief encounters with shear or odor enhances settlement onto substrata below, whereas constant swimming enhances contact with surfaces above or beside larvae). Although microscopic organisms swim slowly relative to ambient water flow, their locomotory behavior in response to the rapidly-fluctuating shears and odors they encounter can affect where they are transported by ambient water movement.

Cellular registration without behavioral recall of olfactory sensory input under general anesthesia.

PubMed

Samuelsson, Andrew R; Brandon, Nicole R; Tang, Pei; Xu, Yan

2014-04-01

Previous studies suggest that sensory information is "received" but not "perceived" under general anesthesia. Whether and to what extent the brain continues to process sensory inputs in a drug-induced unconscious state remain unclear. One hundred seven rats were randomly assigned to 12 different anesthesia and odor exposure paradigms. The immunoreactivities of the immediate early gene products c-Fos and Egr1 as neural activity markers were combined with behavioral tests to assess the integrity and relationship of cellular and behavioral responsiveness to olfactory stimuli under a surgical plane of ketamine-xylazine general anesthesia. The olfactory sensory processing centers could distinguish the presence or absence of experimental odorants even when animals were fully anesthetized. In the anesthetized state, the c-Fos immunoreactivity in the higher olfactory cortices revealed a difference between novel and familiar odorants similar to that seen in the awake state, suggesting that the anesthetized brain functions beyond simply receiving external stimulation. Reexposing animals to odorants previously experienced only under anesthesia resulted in c-Fos immunoreactivity, which was similar to that elicited by familiar odorants, indicating that previous registration had occurred in the anesthetized brain. Despite the "cellular memory," however, odor discrimination and forced-choice odor-recognition tests showed absence of behavioral recall of the registered sensations, except for a longer latency in odor recognition tests. Histologically distinguishable registration of sensory processing continues to occur at the cellular level under ketamine-xylazine general anesthesia despite the absence of behavioral recognition, consistent with the notion that general anesthesia causes disintegration of information processing without completely blocking cellular communications.

Cellular Registration Without Behavioral Recall Of Olfactory Sensory Input Under General Anesthesia

PubMed Central

Samuelsson, Andrew R.; Brandon, Nicole R.; Tang, Pei; Xu, Yan

2014-01-01

Background Previous studies suggest that sensory information is “received” but not “perceived” under general anesthesia. Whether and to what extent the brain continues to process sensory inputs in a drug-induced unconscious state remain unclear. Methods 107 rats were randomly assigned to 12 different anesthesia and odor exposure paradigms. The immunoreactivities of the immediate early gene products c-Fos and Egr1 as neural activity markers were combined with behavioral tests to assess the integrity and relationship of cellular and behavioral responsiveness to olfactory stimuli under a surgical plane of ketamine-xylazine general anesthesia. Results The olfactory sensory processing centers can distinguish the presence or absence of experimental odorants even when animals were fully anesthetized. In the anesthetized state, the c-Fos immunoreactivity in the higher olfactory cortices revealed a difference between novel and familiar odorants similar to that seen in the awake state, suggesting that the anesthetized brain functions beyond simply receiving external stimulation. Re-exposing animals to odorants previously experienced only under anesthesia resulted in c-Fos immunoreactivity similar to that elicited by familiar odorants, indicating that previous registration had occurred in the anesthetized brain. Despite the “cellular memory,” however, odor discrimination and forced-choice odor-recognition tests showed absence of behavioral recall of the registered sensations, except for a longer latency in odor recognition tests. Conclusions Histologically distinguishable registration of sensory process continues to occur at cellular level under ketamine-xylazine general anesthesia despite the absence of behavioral recognition, consistent with the notion that general anesthesia causes disintegration of information processing without completely blocking cellular communications. PMID:24694846

Odor-color associations differ with verbal descriptors for odors: A comparison of three linguistically diverse groups.

PubMed

de Valk, Josje M; Wnuk, Ewelina; Huisman, John L A; Majid, Asifa

2017-08-01

People appear to have systematic associations between odors and colors. Previous research has emphasized the perceptual nature of these associations, but little attention has been paid to what role language might play. It is possible odor-color associations arise through a process of labeling; that is, participants select a descriptor for an odor and then choose a color accordingly (e.g., banana odor → "banana" label → yellow). If correct, this would predict odor-color associations would differ as odor descriptions differ. We compared speakers of Dutch (who overwhelmingly describe odors by referring to the source; e.g., smells like banana) with speakers of Maniq and Thai (who also describe odors with dedicated, abstract smell vocabulary; e.g., musty), and tested whether the type of descriptor mattered for odor-color associations. Participants were asked to select a color that they associated with an odor on two separate occasions (to test for consistency), and finally to label the odors. We found the hunter-gatherer Maniq showed few, if any, consistent or accurate odor-color associations. More importantly, we found the types of descriptors used to name the smells were related to the odor-color associations. When people used abstract smell terms to describe odors, they were less likely to choose a color match, but when they described an odor with a source-based term, their color choices more accurately reflected the odor source, particularly when the odor source was named correctly (e.g., banana odor → yellow). This suggests language is an important factor in odor-color cross-modal associations.

Two Parallel Olfactory Pathways for Processing General Odors in a Cockroach

PubMed Central

Watanabe, Hidehiro; Nishino, Hiroshi; Mizunami, Makoto; Yokohari, Fumio

2017-01-01

In animals, sensory processing via parallel pathways, including the olfactory system, is a common design. However, the mechanisms that parallel pathways use to encode highly complex and dynamic odor signals remain unclear. In the current study, we examined the anatomical and physiological features of parallel olfactory pathways in an evolutionally basal insect, the cockroach Periplaneta americana. In this insect, the entire system for processing general odors, from olfactory sensory neurons to higher brain centers, is anatomically segregated into two parallel pathways. Two separate populations of secondary olfactory neurons, type1 and type2 projection neurons (PNs), with dendrites in distinct glomerular groups relay olfactory signals to segregated areas of higher brain centers. We conducted intracellular recordings, revealing olfactory properties and temporal patterns of both types of PNs. Generally, type1 PNs exhibit higher odor-specificities to nine tested odorants than type2 PNs. Cluster analyses revealed that odor-evoked responses were temporally complex and varied in type1 PNs, while type2 PNs exhibited phasic on-responses with either early or late latencies to an effective odor. The late responses are 30–40 ms later than the early responses. Simultaneous intracellular recordings from two different PNs revealed that a given odor activated both types of PNs with different temporal patterns, and latencies of early and late responses in type2 PNs might be precisely controlled. Our results suggest that the cockroach is equipped with two anatomically and physiologically segregated parallel olfactory pathways, which might employ different neural strategies to encode odor information. PMID:28529476

Analysis of the application of selected physico-chemical methods in eliminating odor nuisance of municipal facilities

NASA Astrophysics Data System (ADS)

Miller, Urszula; Grzelka, Agnieszka; Romanik, Elżbieta; Kuriata, Magdalena

2018-01-01

Operation of municipal management facilities is inseparable from the problem of malodorous compounds emissions to the atmospheric air. In that case odor nuisance is related to the chemical composition of waste, sewage and sludge as well as to the activity of microorganisms whose products of life processes can be those odorous compounds. Significant reduction of odorant emission from many sources can be achieved by optimizing parameters and conditions of processes. However, it is not always possible to limit the formation of odorants. In such cases it is best to use appropriate deodorizing methods. The choice of the appropriate method is based on in terms of physical parameters, emission intensity of polluted gases and their composition, if it is possible to determine. Among the solutions used in municipal economy, there can be distinguished physico-chemical methods such as sorption and oxidation. In cases where the source of the emission is not encapsulated, odor masking techniques are used, which consists of spraying preparations that neutralize unpleasant odors. The paper presents the characteristics of selected methods of eliminating odor nuisance and evaluation of their applicability in municipal management facilities.

Re-presentation of Olfactory Exposure Therapy Success Cues during Non-Rapid Eye Movement Sleep did not Increase Therapy Outcome but Increased Sleep Spindles

PubMed Central

Rihm, Julia S.; Sollberger, Silja B.; Soravia, Leila M.; Rasch, Björn

2016-01-01

Exposure therapy induces extinction learning and is an effective treatment for specific phobias. Sleep after learning promotes extinction memory and benefits therapy success. As sleep-dependent memory-enhancing effects are based on memory reactivations during sleep, here we aimed at applying the beneficial effect of sleep on therapy success by cueing memories of subjective therapy success during non-rapid eye movement sleep after in vivo exposure-based group therapy for spider phobia. In addition, oscillatory correlates of re-presentation during sleep (i.e., sleep spindles and slow oscillations) were investigated. After exposure therapy, spider-phobic patients verbalized their subjectively experienced therapy success under presence of a contextual odor. Then, patients napped for 90 min recorded by polysomnography. Half of the sleep group received the odor during sleep while the other half was presented an odorless vehicle as control. A third group served as a wake control group without odor presentation. While exposure therapy significantly reduced spider-phobic symptoms in all subjects, these symptoms could not be further reduced by re-presenting the odor associated with therapy success, probably due to a ceiling effect of the highly effective exposure therapy. However, odor re-exposure during sleep increased left-lateralized frontal slow spindle (11.0–13.0 Hz) and right-lateralized parietal fast spindle (13.0–15.0 Hz) activity, suggesting the possibility of a successful re-presentation of therapy-related memories during sleep. Future studies need to further examine the possibility to enhance therapy success by targeted memory reactivation (TMR) during sleep. PMID:27445775

Subliminal smells can guide social preferences.

PubMed

Li, Wen; Moallem, Isabel; Paller, Ken A; Gottfried, Jay A

2007-12-01

It is widely accepted that unconscious processes can modulate judgments and behavior, but do such influences affect one's daily interactions with other people? Given that olfactory information has relatively direct access to cortical and subcortical emotional circuits, we tested whether the affective content of subliminal odors alters social preferences. Participants rated the likeability of neutral faces after smelling pleasant, neutral, or unpleasant odors delivered below detection thresholds. Odor affect significantly shifted likeability ratings only for those participants lacking conscious awareness of the smells, as verified by chance-level trial-by-trial performance on an odor-detection task. Across participants, the magnitude of this priming effect decreased as sensitivity for odor detection increased. In contrast, heart rate responses tracked odor valence independently of odor awareness. These results indicate that social preferences are subject to influences from odors that escape awareness, whereas the availability of conscious odor information may disrupt such effects.

Default Mode Network (DMN) Deactivation during Odor-Visual Association

PubMed Central

Karunanayaka, Prasanna R.; Wilson, Donald A.; Tobia, Michael J.; Martinez, Brittany; Meadowcroft, Mark; Eslinger, Paul J.; Yang, Qing X.

2017-01-01

Default mode network (DMN) deactivation has been shown to be functionally relevant for goal-directed cognition. In this study, we investigated the DMN’s role during olfactory processing using two complementary functional magnetic resonance imaging (fMRI) paradigms with identical timing, visual-cue stimulation and response monitoring protocols. Twenty-nine healthy, non-smoking, right-handed adults (mean age = 26±4 yrs., 16 females) completed an odor-visual association fMRI paradigm that had two alternating odor+visual and visual-only trial conditions. During odor+visual trials, a visual cue was presented simultaneously with an odor, while during visual-only trial conditions the same visual cue was presented alone. Eighteen of the 29 participants (mean age = 27.0 ± 6.0 yrs.,11 females) also took part in a control no-odor fMRI paradigm that consisted of visual-only trial conditions which were identical to the visual-only trials in the odor-visual association paradigm. We used Independent Component Analysis (ICA), extended unified structural equation modeling (euSEM), and psychophysiological interaction (PPI) to investigate the interplay between the DMN and olfactory network. In the odor-visual association paradigm, DMN deactivation was evoked by both the odor+visual and visual-only trial conditions. In contrast, the visual-only trials in the no-odor paradigm did not evoke consistent DMN deactivation. In the odor-visual association paradigm, the euSEM and PPI analyses identified a directed connectivity between the DMN and olfactory network which was significantly different between odor+visual and visual-only trial conditions. The results support a strong interaction between the DMN and olfactory network and highlights DMN’s role in task-evoked brain activity and behavioral responses during olfactory processing. PMID:27785847

Odor Valence Linearly Modulates Attractiveness, but Not Age Assessment, of Invariant Facial Features in a Memory-Based Rating Task

PubMed Central

Seubert, Janina; Gregory, Kristen M.; Chamberland, Jessica; Dessirier, Jean-Marc; Lundström, Johan N.

2014-01-01

Scented cosmetic products are used across cultures as a way to favorably influence one's appearance. While crossmodal effects of odor valence on perceived attractiveness of facial features have been demonstrated experimentally, it is unknown whether they represent a phenomenon specific to affective processing. In this experiment, we presented odors in the context of a face battery with systematic feature manipulations during a speeded response task. Modulatory effects of linear increases of odor valence were investigated by juxtaposing subsequent memory-based ratings tasks – one predominantly affective (attractiveness) and a second, cognitive (age). The linear modulation pattern observed for attractiveness was consistent with additive effects of face and odor appraisal. Effects of odor valence on age perception were not linearly modulated and may be the result of cognitive interference. Affective and cognitive processing of faces thus appear to differ in their susceptibility to modulation by odors, likely as a result of privileged access of olfactory stimuli to affective brain networks. These results are critically discussed with respect to potential biases introduced by the preceding speeded response task. PMID:24874703

Olfactory experience and the development of odor preference and vaginal marking in female Syrian hamsters.

PubMed

Maras, Pamela M; Petrulis, Aras

2008-07-05

Rodent reproductive behavior relies heavily on odor processing, and evidence suggests that many odor-guided sexual behaviors are shaped by prior experience. We sought to determine if exposure to male odors during development is required for the adult expression of proceptive sexual behavior toward male odors in female Syrian hamsters. Exposure to male odors was restricted in naïve subjects by removing all male siblings from the litter at three to five days of age. Control litters were also culled, but included equal numbers of male and female pups. As adults, naïve females displayed investigatory preferences toward male odors in a Y-maze that were comparable to control females; this preference was observed whether contact with the odor stimuli was prevented of allowed. In contrast, naïve females vaginal scent-marked equally toward male and female volatile odors, suggesting an inability to target behavior toward sexually relevant odors. However, naïve females marked preferentially toward male odors when allowed to contact the odor stimuli. These results provide evidence for the experience-dependent development of vaginal marking behavior toward volatile components of sexual odors. Furthermore, they suggest that distinct mechanisms regulate the development of odor preferences and vaginal marking behavior in this species.

Processing of Intraoral Olfactory and Gustatory Signals in the Gustatory Cortex of Awake Rats

PubMed Central

Fontanini, Alfredo

2017-01-01

The integration of gustatory and olfactory information is essential to the perception of flavor. Human neuroimaging experiments have pointed to the gustatory cortex (GC) as one of the areas involved in mediating flavor perception. Although GC's involvement in encoding the chemical identity and hedonic value of taste stimuli is well studied, it is unknown how single GC neurons process olfactory stimuli emanating from the mouth. In this study, we relied on multielectrode recordings to investigate how single GC neurons respond to intraorally delivered tastants and tasteless odorants dissolved in water and whether/how these two modalities converge in the same neurons. We found that GC neurons could either be unimodal, responding exclusively to taste (taste-only) or odor (odor-only), or bimodal, responding to both gustatory and olfactory stimuli. Odor responses were confirmed to result from retronasal olfaction: monitoring respiration revealed that exhalation preceded odor-evoked activity and reversible inactivation of olfactory receptors in the nasal epithelium significantly reduced responses to intraoral odorants but not to tastants. Analysis of bimodal neurons revealed that they encode palatability significantly better than the unimodal taste-only group. Bimodal neurons exhibited similar responses to palatable tastants and odorants dissolved in water. This result suggested that odorized water could be palatable. This interpretation was further supported with a brief access task, where rats avoided consuming aversive taste stimuli and consumed the palatable tastants and dissolved odorants. These results demonstrate the convergence of the chemosensory components of flavor onto single GC neurons and provide evidence for the integration of flavor with palatability coding. SIGNIFICANCE STATEMENT Food perception and choice depend upon the concurrent processing of olfactory and gustatory signals from the mouth. The primary gustatory cortex has been proposed to integrate chemosensory stimuli; however, no study has examined the single-unit responses to intraoral odorant presentation. Here we found that neurons in gustatory cortex can respond either exclusively to tastants, exclusively to odorants, or to both (bimodal). Several differences exist between these groups' responses; notably, bimodal neurons code palatability significantly better than unimodal neurons. This group of neurons might represent a substrate for how odorants gain the quality of tastants. PMID:28077705

Seeing odors in color: Cross-modal associations in children and adults from two cultural environments.

PubMed

Goubet, Nathalie; Durand, Karine; Schaal, Benoist; McCall, Daniel D

2018-02-01

We investigated the occurrence and underlying processes of odor-color associations in French and American 6- to 10-year-old children (n = 386) and adults (n = 137). Nine odorants were chosen according to their familiarity to either cultural group. Participants matched each odor with a color, gave hedonic and familiarity judgments, and identified each odor. By 6 years of age, children displayed culture-specific odor-color associations, but age differences were noted in the type of associations. Children and adults in both cultural groups shared common associations and formed associations that were unique to their environment, underscoring the importance of exposure learning in odor-color associations. Copyright © 2017 Elsevier Inc. All rights reserved.

Modelling of composting process of different organic waste at pilot scale: Biodegradability and odor emissions.

PubMed

Gutiérrez, M C; Siles, J A; Diz, J; Chica, A F; Martín, M A

2017-01-01

The composting process of six different compostable substrates and one of these with the addition of bacterial inoculums carried out in a dynamic respirometer was evaluated. Despite the heterogeneity of the compostable substrates, cumulative oxygen demand (OD, mgO 2 kgVS) was fitted adequately to an exponential regression growing until reaching a maximum in all cases. According to the kinetic constant of the reaction (K) values obtained, the wastes that degraded more slowly were those containing lignocellulosic material (green wastes) or less biodegradable wastes (sewage sludge). The odor emissions generated during the composting processes were also fitted in all cases to a Gaussian regression with R 2 values within the range 0.8-0.9. The model was validated representing real odor concentration near the maximum value against predicted odor concentration of each substrate, (R 2 =0.9314; 95% prediction interval). The variables of maximum odor concentration (ou E /m 3 ) and the time (h) at which the maximum was reached were also evaluated statistically using ANOVA and a post-hoc Tukey test taking the substrate as a factor, which allowed homogeneous groups to be obtained according to one or both of these variables. The maximum oxygen consumption rate or organic matter degradation during composting was directly related to the maximum odor emission generation rate (R 2 =0.9024, 95% confidence interval) when only the organic wastes with a low content in lignocellulosic materials and no inoculated waste (HRIO) were considered. Finally, the composting of OFMSW would produce a higher odor impact than the other substrates if this process was carried out without odor control or open systems. Copyright © 2016 Elsevier Ltd. All rights reserved.

Processing of odor mixtures in the zebrafish olfactory bulb.

PubMed

Tabor, Rico; Yaksi, Emre; Weislogel, Jan-Marek; Friedrich, Rainer W

2004-07-21

Components of odor mixtures often are not perceived individually, suggesting that neural representations of mixtures are not simple combinations of the representations of the components. We studied odor responses to binary mixtures of amino acids and food extracts at different processing stages in the olfactory bulb (OB) of zebrafish. Odor-evoked input to the OB was measured by imaging Ca2+ signals in afferents to olfactory glomeruli. Activity patterns evoked by mixtures were predictable within narrow limits from the component patterns, indicating that mixture interactions in the peripheral olfactory system are weak. OB output neurons, the mitral cells (MCs), were recorded extra- and intracellularly and responded to odors with stimulus-dependent temporal firing rate modulations. Responses to mixtures of amino acids often were dominated by one of the component responses. Responses to mixtures of food extracts, in contrast, were more distinct from both component responses. These results show that mixture interactions can result from processing in the OB. Moreover, our data indicate that mixture interactions in the OB become more pronounced with increasing overlap of input activity patterns evoked by the components. Emerging from these results are rules of mixture interactions that may explain behavioral data and provide a basis for understanding the processing of natural odor stimuli in the OB.

Adaptive adjustment of the generalization-discrimination balance in larval Drosophila.

PubMed

Mishra, Dushyant; Louis, Matthieu; Gerber, Bertram

2010-09-01

Learnt predictive behavior faces a dilemma: predictive stimuli will never 'replay' exactly as during the learning event, requiring generalization. In turn, minute differences can become meaningful, prompting discrimination. To provide a study case for an adaptive adjustment of this generalization-discrimination balance, the authors ask whether Drosophila melanogaster larvae are able to either generalize or discriminate between two odors (1-octen-3-ol and 3-octanol), depending on the task. The authors find that after discriminatively rewarding one but not the other odor, larvae show conditioned preference for the rewarded odor. On the other hand, no odor specificity is observed after nondiscriminative training, even if the test involves a choice between both odors. Thus, for this odor pair at least, discrimination training is required to confer an odor-specific memory trace. This requires that there is at least some difference in processing between the two odors already at the beginning of the training. Therefore, as a default, there is a small yet salient difference in processing between 1-octen-3-ol and 3-octanol; this difference is ignored after nondiscriminative training (generalization), whereas it is accentuated by odor-specific reinforcement (discrimination). Given that, as the authors show, both faculties are lost in anosmic Or83b(1) mutants, this indicates an adaptive adjustment of the generalization-discrimination balance in larval Drosophila, taking place downstream of Or83b-expressing sensory neurons.

Morphology and physiology of the olfactory system of blood-feeding insects.

PubMed

Guidobaldi, F; May-Concha, I J; Guerenstein, P G

2014-01-01

Several blood-feeding (hematophagous) insects are vectors of a number of diseases including dengue, Chagas disease and leishmaniasis which persistently affect public health throughout Latin America. The vectors of those diseases include mosquitoes, triatomine bugs and sandflies. As vector control is an efficient way to prevent these illnesses it is important to understand the sensory biology of those harmful insects. We study the physiology of the olfactory system of those insects and apply that knowledge on the development of methods to manipulate their behavior. Here we review some of the latest information on insect olfaction with emphasis on hematophagous insects. The insect olfactory sensory neurons are housed inside hair-like organs called sensilla which are mainly distributed on the antenna and mouthparts. The identity of many of the odor compounds that those neurons detect are already known in hematophagous insects. They include several constituents of host (vertebrate) odor, sex, aggregation and alarm pheromones, and compounds related to egg-deposition behavior. Recent work has contributed significant knowledge on how odor information is processed in the insect first odor-processing center in the brain, the antennal lobe. The quality, quantity, and temporal features of the odor stimuli are encoded by the neural networks of the antennal lobe. Information regarding odor mixtures is also encoded. While natural mixtures evoke strong responses, synthetic mixtures that deviate from their natural counterparts in terms of key constituents or proportions of those constituents evoke weaker responses. The processing of olfactory information is largely unexplored in hematophagous insects. However, many aspects of their olfactory behavior are known. As in other insects, responses to relevant single odor compounds are weak while natural mixtures evoke strong responses. Future challenges include studying how information about odor mixtures is processed in their brain. This could help develop highly attractive synthetic odor blends to lure them into traps. Copyright © 2014 Elsevier Ltd. All rights reserved.

Odor compounds in waste gas emissions from agricultural operations and food industries.

PubMed

Rappert, S; Müller, R

2005-01-01

In the last decades, large-scale agricultural operations and food industries have increased. These operations generate numerous types of odors. The reduction of land areas available for isolation of agricultural and food processing industrial operations from the public area and the increase in sensitivity and demand of the general public for a clean and pleasant environment have forced all of these industries to control odor emissions and toxic air pollutants. To develop environmentally sound, sustainable agricultural and food industrial operations, it is necessary to integrate research that focuses on modern analytical techniques and latest sensory technology of measurement and evaluation of odor and pollution, together with a fundamental knowledge of factors that are the basic units contributing to the production of odor and pollutants. Without a clear understanding of what odor is, how to measure it, and where it originates, it will be difficult to control the odor. The present paper reviews the available information regarding odor emissions from agricultural operations and food industries by giving an overview about odor problems, odor detection and quantification, and identifying the sources and the mechanisms that contribute to the odor emissions. Finally, ways of reducing or controlling the odor problem are discussed.

The Regular Interaction Pattern among Odorants of the Same Type and Its Application in Odor Intensity Assessment.

PubMed

Yan, Luchun; Liu, Jiemin; Jiang, Shen; Wu, Chuandong; Gao, Kewei

2017-07-13

The olfactory evaluation function (e.g., odor intensity rating) of e-nose is always one of the most challenging issues in researches about odor pollution monitoring. But odor is normally produced by a set of stimuli, and odor interactions among constituents significantly influenced their mixture's odor intensity. This study investigated the odor interaction principle in odor mixtures of aldehydes and esters, respectively. Then, a modified vector model (MVM) was proposed and it successfully demonstrated the similarity of the odor interaction pattern among odorants of the same type. Based on the regular interaction pattern, unlike a determined empirical model only fit for a specific odor mixture in conventional approaches, the MVM distinctly simplified the odor intensity prediction of odor mixtures. Furthermore, the MVM also provided a way of directly converting constituents' chemical concentrations to their mixture's odor intensity. By combining the MVM with usual data-processing algorithm of e-nose, a new e-nose system was established for an odor intensity rating. Compared with instrumental analysis and human assessor, it exhibited accuracy well in both quantitative analysis (Pearson correlation coefficient was 0.999 for individual aldehydes ( n = 12), 0.996 for their binary mixtures ( n = 36) and 0.990 for their ternary mixtures ( n = 60)) and odor intensity assessment (Pearson correlation coefficient was 0.980 for individual aldehydes ( n = 15), 0.973 for their binary mixtures ( n = 24), and 0.888 for their ternary mixtures ( n = 25)). Thus, the observed regular interaction pattern is considered an important foundation for accelerating extensive application of olfactory evaluation in odor pollution monitoring.

Coding of odors by temporal binding within a model network of the locust antennal lobe.

PubMed

Patel, Mainak J; Rangan, Aaditya V; Cai, David

2013-01-01

The locust olfactory system interfaces with the external world through antennal receptor neurons (ORNs), which represent odors in a distributed, combinatorial manner. ORN axons bundle together to form the antennal nerve, which relays sensory information centrally to the antennal lobe (AL). Within the AL, an odor generates a dynamically evolving ensemble of active cells, leading to a stimulus-specific temporal progression of neuronal spiking. This experimental observation has led to the hypothesis that an odor is encoded within the AL by a dynamically evolving trajectory of projection neuron (PN) activity that can be decoded piecewise to ascertain odor identity. In order to study information coding within the locust AL, we developed a scaled-down model of the locust AL using Hodgkin-Huxley-type neurons and biologically realistic connectivity parameters and current components. Using our model, we examined correlations in the precise timing of spikes across multiple neurons, and our results suggest an alternative to the dynamic trajectory hypothesis. We propose that the dynamical interplay of fast and slow inhibition within the locust AL induces temporally stable correlations in the spiking activity of an odor-dependent neural subset, giving rise to a temporal binding code that allows rapid stimulus detection by downstream elements.

Odor Signals of Immune Activation and CNS Inflammation

DTIC Science & Technology

2014-12-01

inflammation results in detectable alteration of body odor and that traumatic brain injury (TBI) might similarly produce volatile metabolites specific to...Because both LPS and TBI elicit inflammatory processes and LPS-induced inflammation induces body odor changes, we hypothesized that (1) TBI would...induce a distinct change in body odor and (2) this change would resemble the change induced by LPS. Mice receiving surgery and lateral fluid percussion

Learning about natural variation of odor mixtures enhances categorization in early olfactory processing.

PubMed

Locatelli, Fernando F; Fernandez, Patricia C; Smith, Brian H

2016-09-01

Natural odors are typically mixtures of several chemical components. Mixtures vary in composition among odor objects that have the same meaning. Therefore a central 'categorization' problem for an animal as it makes decisions about odors in natural contexts is to correctly identify odor variants that have the same meaning and avoid variants that have a different meaning. We propose that identified mechanisms of associative and non-associative plasticity in early sensory processing in the insect antennal lobe and mammalian olfactory bulb are central to solving this problem. Accordingly, this plasticity should work to improve categorization of odors that have the opposite meanings in relation to important events. Using synthetic mixtures designed to mimic natural odor variation among flowers, we studied how honey bees learn about and generalize among floral odors associated with food. We behaviorally conditioned honey bees on a difficult odor discrimination problem using synthetic mixtures that mimic natural variation among snapdragon flowers. We then used calcium imaging to measure responses of projection neurons of the antennal lobe, which is the first synaptic relay of olfactory sensory information in the brain, to study how ensembles of projection neurons change as a result of behavioral conditioning. We show how these ensembles become 'tuned' through plasticity to improve categorization of odors that have the different meanings. We argue that this tuning allows more efficient use of the immense coding space of the antennal lobe and olfactory bulb to solve the categorization problem. Our data point to the need for a better understanding of the 'statistics' of the odor space. © 2016. Published by The Company of Biologists Ltd.

Honey bee odorant-binding protein 14: effects on thermal stability upon odorant binding revealed by FT-IR spectroscopy and CD measurements.

PubMed

Schwaighofer, Andreas; Kotlowski, Caroline; Araman, Can; Chu, Nam; Mastrogiacomo, Rosa; Becker, Christian; Pelosi, Paolo; Knoll, Wolfgang; Larisika, Melanie; Nowak, Christoph

2014-03-01

In the present work, we study the effect of odorant binding on the thermal stability of honey bee (Apis mellifera L.) odorant-binding protein 14. Thermal denaturation of the protein in the absence and presence of different odorant molecules was monitored by Fourier transform infrared spectroscopy (FT-IR) and circular dichroism (CD). FT-IR spectra show characteristic bands for intermolecular aggregation through the formation of intermolecular β-sheets during the heating process. Transition temperatures in the FT-IR spectra were evaluated using moving-window 2D correlation maps and confirmed by CD measurements. The obtained results reveal an increase of the denaturation temperature of the protein when bound to an odorant molecule. We could also discriminate between high- and low-affinity odorants by determining transition temperatures, as demonstrated independently by the two applied methodologies. The increased thermal stability in the presence of ligands is attributed to a stabilizing effect of non-covalent interactions between odorant-binding protein 14 and the odorant molecule.

Influence of the chemical structure on odor qualities and odor thresholds of halogenated guaiacol-derived odorants

NASA Astrophysics Data System (ADS)

Juhlke, Florian; Lorber, Katja; Wagenstaller, Maria; Buettner, Andrea

2017-12-01

Chlorinated guaiacol derivatives are found in waste water of pulp mills using chlorine in the bleaching process of wood pulp. They can also be detected in fish tissue, possibly causing off-odors. To date, there is no systematic investigation on the odor properties of halogenated guaiacol derivatives. To close this gap, odor thresholds in air and odor qualities of 14 compounds were determined by gas chromatography-olfactometry. Overall, the investigated compounds elicited smells that are characteristic for guaiacol, namely smoky, sweet, vanilla-like, but also medicinal and plaster-like. Their odor thresholds in air were, however, very low, ranging from 0.00072 to 23 ng/Lair. The lowest thresholds were found for 5-chloro- and 5-bromoguaiacol, followed by 4,5-dichloro- and 6-chloroguaiacol. Moreover, some inter-individual differences in odor threshold values could be observed, with the highest variations having been recorded for the individual values of 5-iodo- and 4-bromoguaiacol.

Molecular Basis of Olfactory Chemoreception in the Common Bed Bug, Cimex lectularius.

PubMed

Liu, Feng; Chen, Zhou; Liu, Nannan

2017-04-06

As one of the most notorious ectoparasites, bed bugs rely heavily on human or animal blood sources for survival, mating and reproduction. Chemoreception, mediated by the odorant receptors on the membrane of olfactory sensory neurons, plays a vital role in their host seeking and risk aversion processes. We investigated the responses of odorant receptors to a large spectrum of semiochemicals, including human odorants and plant-released volatiles and found that strong responses were sparse; aldehydes/ketones were the most efficient stimuli, while carboxylic acids and aliphatics/aromatics were comparatively less effective in eliciting responses from bed bug odorant receptors. In bed bugs, both the odorant identity and concentrations play important roles in determining the strength of these responses. The odor space constructed based on the responses from all the odorant receptors tested revealed that odorants within the same chemical group are widely dispersed while odorants from different groups are intermingled, suggesting the complexity of odorant encoding in the bed bug odorant receptors. This study provides a comprehensive picture of the olfactory coding mechanisms of bed bugs that will ultimately contribute to the design and development of novel olfactory-based strategies to reduce both the biting nuisance and disease transmission from bed bugs.

Peripheral and Central Olfactory Tuning in a Moth

PubMed Central

Ong, Rose C.

2012-01-01

Animals can be innately attracted to certain odorants. Because these attractants are particularly salient, they might be expected to induce relatively strong responses throughout the olfactory pathway, helping animals detect the most relevant odors but limiting flexibility to respond to other odors. Alternatively, specific neural wiring might link innately preferred odors to appropriate behaviors without a need for intensity biases. How nonpheromonal attractants are processed by the general olfactory system remains largely unknown. In the moth Manduca sexta, we studied this with a set of innately preferred host plant odors and other, neutral odors. Electroantennogram recordings showed that, as a population, olfactory receptor neurons (ORNs) did not respond with greater intensity to host plant odors, and further local field potential recordings showed that no specific amplification of signals induced by host plant odors occurred between the first olfactory center and the second. Moreover, when odorants were mutually diluted to elicit equally intense output from the ORNs, moths were able to learn to associate all tested odorants equally well with food reward. Together, these results suggest that, although nonpheromonal host plant odors activate broadly distributed responses, they may be linked to attractive behaviors mainly through specific wiring in the brain. PMID:22362866

A review on the neural bases of episodic odor memory: from laboratory-based to autobiographical approaches

PubMed Central

Saive, Anne-Lise; Royet, Jean-Pierre; Plailly, Jane

2014-01-01

Odors are powerful cues that trigger episodic memories. However, in light of the amount of behavioral data describing the characteristics of episodic odor memory, the paucity of information available on the neural substrates of this function is startling. Furthermore, the diversity of experimental paradigms complicates the identification of a generic episodic odor memory network. We conduct a systematic review of the literature depicting the current state of the neural correlates of episodic odor memory in healthy humans by placing a focus on the experimental approaches. Functional neuroimaging data are introduced by a brief characterization of the memory processes investigated. We present and discuss laboratory-based approaches, such as odor recognition and odor associative memory, and autobiographical approaches, such as the evaluation of odor familiarity and odor-evoked autobiographical memory. We then suggest the development of new laboratory-ecological approaches allowing for the controlled encoding and retrieval of specific multidimensional events that could open up new prospects for the comprehension of episodic odor memory and its neural underpinnings. While large conceptual differences distinguish experimental approaches, the overview of the functional neuroimaging findings suggests relatively stable neural correlates of episodic odor memory. PMID:25071494

Variable selection based cotton bollworm odor spectroscopic detection

NASA Astrophysics Data System (ADS)

Lü, Chengxu; Gai, Shasha; Luo, Min; Zhao, Bo

2016-10-01

Aiming at rapid automatic pest detection based efficient and targeting pesticide application and shooting the trouble of reflectance spectral signal covered and attenuated by the solid plant, the possibility of near infrared spectroscopy (NIRS) detection on cotton bollworm odor is studied. Three cotton bollworm odor samples and 3 blank air gas samples were prepared. Different concentrations of cotton bollworm odor were prepared by mixing the above gas samples, resulting a calibration group of 62 samples and a validation group of 31 samples. Spectral collection system includes light source, optical fiber, sample chamber, spectrometer. Spectra were pretreated by baseline correction, modeled with partial least squares (PLS), and optimized by genetic algorithm (GA) and competitive adaptive reweighted sampling (CARS). Minor counts differences are found among spectra of different cotton bollworm odor concentrations. PLS model of all the variables was built presenting RMSEV of 14 and RV2 of 0.89, its theory basis is insect volatilizes specific odor, including pheromone and allelochemics, which are used for intra-specific and inter-specific communication and could be detected by NIR spectroscopy. 28 sensitive variables are selected by GA, presenting the model performance of RMSEV of 14 and RV2 of 0.90. Comparably, 8 sensitive variables are selected by CARS, presenting the model performance of RMSEV of 13 and RV2 of 0.92. CARS model employs only 1.5% variables presenting smaller error than that of all variable. Odor gas based NIR technique shows the potential for cotton bollworm detection.

Volatile organic compound flux from manure of cattle fed diets differing in grain processing method and co-product inclusion

NASA Astrophysics Data System (ADS)

Hales, Kristin; Parker, David B.; Cole, N. Andy

2015-01-01

Odor emissions from livestock production have become increasingly important in the past decade. Odors derived from animal feeding operations are caused by odorous VOC emitted from the mixture of feces and urine, as well as feed and silage which may be experiencing microbial fermentation. Distillers grains are a by-product of corn grain fermentation used to produce fuel ethanol, and this industry has grown rapidly throughout the U.S. in past years. Therefore, the use of wet distillers grains with solubles (WDGS) in feedlot cattle diets has also increased. The objective of this research was to determine specific VOC emissions from feces and urine or a mixture of both, from cattle fed steam flaked or dry-rolled corn (DRC)-based diets containing either 0% or 30% WDGS. Flux of dimethyl trisulfide was greater from feces of cattle fed DRC than steam-flaked corn (SFC) diets. No other differences in flux from feces were detected across dietary treatments for phenol, 4-methylphenol, indole, skatole, dimethyl disulfide, and flux of volatile fatty acids (VFA) such as acetic, propionic, isobutyric, butyric, isovaleric, and valeric acids (P > 0.15). Flux of skatole, acetic acid, and valeric acid from urine was greater for cattle fed SFC than DRC diets (P < 0.05). Moreover, dimethyl disulfide flux was greater for cattle fed DRC vs. SFC diets (P = 0.05). When evaluating WDGS inclusion in the diet, flux of acetic acid and heptanoic acid from urine was greater when cattle were fed diets containing 0% WDGS than 30% WDGS (P < 0.05). When combining urine and feces in the ratio in which they were excreted from the animal, flux of propionic acid was greater when cattle were fed DRC vs. SFC diets (P = 0.05). Based on these results, the majority of the VOC, VFA, and odor flux from cattle feeding operations is from the urine. Therefore, dietary strategies to reduce odor from cattle feeding facilities should primarily focus on reducing excretion of odorous compounds in the urine.

Hot and Cold Smells: Odor-Temperature Associations across Cultures

PubMed Central

Wnuk, Ewelina; de Valk, Josje M.; Huisman, John L. A.; Majid, Asifa

2017-01-01

It is often assumed odors are associated with hot and cold temperature, since odor processing may trigger thermal sensations, such as coolness in the case of mint. It is unknown, however, whether people make consistent temperature associations for a variety of everyday odors, and, if so, what determines them. Previous work investigating the bases of cross-modal associations suggests a number of possibilities, including universal forces (e.g., perception), as well as culture-specific forces (e.g., language and cultural beliefs). In this study, we examined odor-temperature associations in three cultures—Maniq (N = 11), Thai (N = 24), and Dutch (N = 24)—who differ with respect to their cultural preoccupation with odors, their odor lexicons, and their beliefs about the relationship of odors (and odor objects) to temperature. Participants matched 15 odors to temperature by touching cups filled with hot or cold water, and described the odors in their native language. The results showed no consistent associations among the Maniq, and only a handful of consistent associations between odor and temperature among the Thai and Dutch. The consistent associations differed across the two groups, arguing against their universality. Further analysis revealed cross-modal associations could not be explained by language, but could be the result of cultural beliefs. PMID:28848482

Processing of Intraoral Olfactory and Gustatory Signals in the Gustatory Cortex of Awake Rats.

PubMed

Samuelsen, Chad L; Fontanini, Alfredo

2017-01-11

The integration of gustatory and olfactory information is essential to the perception of flavor. Human neuroimaging experiments have pointed to the gustatory cortex (GC) as one of the areas involved in mediating flavor perception. Although GC's involvement in encoding the chemical identity and hedonic value of taste stimuli is well studied, it is unknown how single GC neurons process olfactory stimuli emanating from the mouth. In this study, we relied on multielectrode recordings to investigate how single GC neurons respond to intraorally delivered tastants and tasteless odorants dissolved in water and whether/how these two modalities converge in the same neurons. We found that GC neurons could either be unimodal, responding exclusively to taste (taste-only) or odor (odor-only), or bimodal, responding to both gustatory and olfactory stimuli. Odor responses were confirmed to result from retronasal olfaction: monitoring respiration revealed that exhalation preceded odor-evoked activity and reversible inactivation of olfactory receptors in the nasal epithelium significantly reduced responses to intraoral odorants but not to tastants. Analysis of bimodal neurons revealed that they encode palatability significantly better than the unimodal taste-only group. Bimodal neurons exhibited similar responses to palatable tastants and odorants dissolved in water. This result suggested that odorized water could be palatable. This interpretation was further supported with a brief access task, where rats avoided consuming aversive taste stimuli and consumed the palatable tastants and dissolved odorants. These results demonstrate the convergence of the chemosensory components of flavor onto single GC neurons and provide evidence for the integration of flavor with palatability coding. Food perception and choice depend upon the concurrent processing of olfactory and gustatory signals from the mouth. The primary gustatory cortex has been proposed to integrate chemosensory stimuli; however, no study has examined the single-unit responses to intraoral odorant presentation. Here we found that neurons in gustatory cortex can respond either exclusively to tastants, exclusively to odorants, or to both (bimodal). Several differences exist between these groups' responses; notably, bimodal neurons code palatability significantly better than unimodal neurons. This group of neurons might represent a substrate for how odorants gain the quality of tastants. Copyright © 2017 the authors 0270-6474/17/370244-14$15.00/0.

Membrane Inlet Mass Spectrometry for Homeland Security and Forensic Applications

NASA Astrophysics Data System (ADS)

Giannoukos, Stamatios; Brkić, Boris; Taylor, Stephen; France, Neil

2015-02-01

A man-portable membrane inlet mass spectrometer has been built and tested to detect and monitor characteristic odors emitted from the human body and also from threat substances. In each case, a heated membrane sampling probe was used. During human scent monitoring experiments, data were obtained for inorganic gases and volatile organic compounds emitted from human breath and sweat in a confined space. Volatile emissions were detected from the human body at low ppb concentrations. Experiments with compounds associated with narcotics, explosives, and chemical warfare agents were conducted for a range of membrane types. Test compounds included methyl benzoate (odor signature of cocaine), piperidine (precursor in clandestine phencyclidine manufacturing processes), 2-nitrotoluene (breakdown product of TNT), cyclohexanone (volatile signature of plastic explosives), dimethyl methylphosphonate (used in sarin and soman nerve agent production), and 2-chloroethyl ethyl sulfide (simulant compound for sulfur mustard gas). Gas phase calibration experiments were performed allowing sub-ppb LOD to be established. The results showed excellent linearity versus concentration and rapid membrane response times.

Membrane inlet mass spectrometry for homeland security and forensic applications.

PubMed

Giannoukos, Stamatios; Brkić, Boris; Taylor, Stephen; France, Neil

2015-02-01

A man-portable membrane inlet mass spectrometer has been built and tested to detect and monitor characteristic odors emitted from the human body and also from threat substances. In each case, a heated membrane sampling probe was used. During human scent monitoring experiments, data were obtained for inorganic gases and volatile organic compounds emitted from human breath and sweat in a confined space. Volatile emissions were detected from the human body at low ppb concentrations. Experiments with compounds associated with narcotics, explosives, and chemical warfare agents were conducted for a range of membrane types. Test compounds included methyl benzoate (odor signature of cocaine), piperidine (precursor in clandestine phencyclidine manufacturing processes), 2-nitrotoluene (breakdown product of TNT), cyclohexanone (volatile signature of plastic explosives), dimethyl methylphosphonate (used in sarin and soman nerve agent production), and 2-chloroethyl ethyl sulfide (simulant compound for sulfur mustard gas). Gas phase calibration experiments were performed allowing sub-ppb LOD to be established. The results showed excellent linearity versus concentration and rapid membrane response times.

Transfer behavior of odorous pollutants in wastewater sludge system under typical chemical conditioning processes for dewaterability enhancement.

PubMed

Gao, Hongyu; Zhang, Weijun; Song, Zhenzhen; Yang, Xiaofang; Yang, Lian; Cao, Mengdi; Wang, Dongsheng; Liao, Guiying

2017-06-13

Chemical conditioning has been used for enhancing wastewater sludge dewaterability for many years, but the characteristics of odorous pollutants emission in sludge conditioning were still unclear. In this work, the transfer behavior of different odorous pollutants between air, liquid and solid phases under typical chemical conditioning processes for high-pressure dewatering was systematically investigated. The results indicated that that besides hydrogen sulfide (H 2 S) and ammonia (NH 3 ), 21 kinds of volatile organic contaminants (VOCs) were identified and quantified by gas chromatography-mass spectrometry (GC-MS), while the concentrations and composition of odorous pollutants varied greatly for different conditioning processes. VOCs were composed by three main constituents including benzenes, halogeno benzene and hydrocarbons. According to mass balance analysis, about 50% of VOCs adsorbed within sludge extracellular polymeric substances (EPS) fraction. Since EPS was damaged and/or flocculation in different chemical conditioning processes, VOCs distributed in solid phase transformed into liquid phase and then released into air. The discrepancies in mass of odorous pollutants before and after chemical conditioning were likely to be related to chemical conversion under acidification, oxidation and precipitation in the presence of ferric ions.

Functional imaging of cortical feedback projections to the olfactory bulb

PubMed Central

Rothermel, Markus; Wachowiak, Matt

2014-01-01

Processing of sensory information is substantially shaped by centrifugal, or feedback, projections from higher cortical areas, yet the functional properties of these projections are poorly characterized. Here, we used genetically-encoded calcium sensors (GCaMPs) to functionally image activation of centrifugal projections targeting the olfactory bulb (OB). The OB receives massive centrifugal input from cortical areas but there has been as yet no characterization of their activity in vivo. We focused on projections to the OB from the anterior olfactory nucleus (AON), a major source of cortical feedback to the OB. We expressed GCaMP selectively in AON projection neurons using a mouse line expressing Cre recombinase (Cre) in these neurons and Cre-dependent viral vectors injected into AON, allowing us to image GCaMP fluorescence signals from their axon terminals in the OB. Electrical stimulation of AON evoked large fluorescence signals that could be imaged from the dorsal OB surface in vivo. Surprisingly, odorants also evoked large signals that were transient and coupled to odorant inhalation both in the anesthetized and awake mouse, suggesting that feedback from AON to the OB is rapid and robust across different brain states. The strength of AON feedback signals increased during wakefulness, suggesting a state-dependent modulation of cortical feedback to the OB. Two-photon GCaMP imaging revealed that different odorants activated different subsets of centrifugal AON axons and could elicit both excitation and suppression in different axons, indicating a surprising richness in the representation of odor information by cortical feedback to the OB. Finally, we found that activating neuromodulatory centers such as basal forebrain drove AON inputs to the OB independent of odorant stimulation. Our results point to the AON as a multifunctional cortical area that provides ongoing feedback to the OB and also serves as a descending relay for other neuromodulatory systems. PMID:25071454

Flies dynamically anti-track, rather than ballistically escape, aversive odor during flight.

PubMed

Wasserman, Sara; Lu, Patrick; Aptekar, Jacob W; Frye, Mark A

2012-08-15

Tracking distant odor sources is crucial to foraging, courtship and reproductive success for many animals including fish, flies and birds. Upon encountering a chemical plume in flight, Drosophila melanogaster integrates the spatial intensity gradient and temporal fluctuations over the two antennae, while simultaneously reducing the amplitude and frequency of rapid steering maneuvers, stabilizing the flight vector. There are infinite escape vectors away from a noxious source, in contrast to a single best tracking vector towards an attractive source. Attractive and aversive odors are segregated into parallel neuronal pathways in flies; therefore, the behavioral algorithms for avoidance may be categorically different from tracking. Do flies plot random ballistic or otherwise variable escape vectors? Or do they instead make use of temporally dynamic mechanisms for continuously and directly avoiding noxious odors in a manner similar to tracking appetitive ones? We examine this question using a magnetic tether flight simulator that permits free yaw movements, such that flies can actively orient within spatially defined odor plumes. We show that in-flight aversive flight behavior shares all of the key features of attraction such that flies continuously 'anti-track' the noxious source.

Flies dynamically anti-track, rather than ballistically escape, aversive odor during flight

PubMed Central

Wasserman, Sara; Lu, Patrick; Aptekar, Jacob W.; Frye, Mark A.

2012-01-01

SUMMARY Tracking distant odor sources is crucial to foraging, courtship and reproductive success for many animals including fish, flies and birds. Upon encountering a chemical plume in flight, Drosophila melanogaster integrates the spatial intensity gradient and temporal fluctuations over the two antennae, while simultaneously reducing the amplitude and frequency of rapid steering maneuvers, stabilizing the flight vector. There are infinite escape vectors away from a noxious source, in contrast to a single best tracking vector towards an attractive source. Attractive and aversive odors are segregated into parallel neuronal pathways in flies; therefore, the behavioral algorithms for avoidance may be categorically different from tracking. Do flies plot random ballistic or otherwise variable escape vectors? Or do they instead make use of temporally dynamic mechanisms for continuously and directly avoiding noxious odors in a manner similar to tracking appetitive ones? We examine this question using a magnetic tether flight simulator that permits free yaw movements, such that flies can actively orient within spatially defined odor plumes. We show that in-flight aversive flight behavior shares all of the key features of attraction such that flies continuously ‘anti-track’ the noxious source. PMID:22837456

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

NASA Astrophysics Data System (ADS)

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

2017-04-01

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

Olfactory Interference during Inhibitory Backward Pairing in Honey Bees

PubMed Central

Dacher, Matthieu; Smith, Brian H.

2008-01-01

Background Restrained worker honey bees are a valuable model for studying the behavioral and neural bases of olfactory plasticity. The proboscis extension response (PER; the proboscis is the mouthpart of honey bees) is released in response to sucrose stimulation. If sucrose stimulation is preceded one or a few times by an odor (forward pairing), the bee will form a memory for this association, and subsequent presentations of the odor alone are sufficient to elicit the PER. However, backward pairing between the two stimuli (sucrose, then odor) has not been studied to any great extent in bees, although the vertebrate literature indicates that it elicits a form of inhibitory plasticity. Methodology/Principal Findings If hungry bees are fed with sucrose, they will release a long lasting PER; however, this PER can be interrupted if an odor is presented 15 seconds (but not 7 or 30 seconds) after the sucrose (backward pairing). We refer to this previously unreported process as olfactory interference. Bees receiving this 15 second backward pairing show reduced performance after a subsequent single forward pairing (excitatory conditioning) trial. Analysis of the results supported a relationship between olfactory interference and a form of backward pairing-induced inhibitory learning/memory. Injecting the drug cimetidine into the deutocerebrum impaired olfactory interference. Conclusions/Significance Olfactory interference depends on the associative link between odor and PER, rather than between odor and sucrose. Furthermore, pairing an odor with sucrose can lead either to association of this odor to PER or to the inhibition of PER by this odor. Olfactory interference may provide insight into processes that gate how excitatory and inhibitory memories for odor-PER associations are formed. PMID:18946512

Association between major depressive disorder and odor identification impairment.

PubMed

Khil, Laura; Rahe, Corinna; Wellmann, Jürgen; Baune, Bernhard T; Wersching, Heike; Berger, Klaus

2016-10-01

There is evidence of olfactory deficits in patients with major depressive disorder (MDD) but causes and mechanisms are largely unknown. We compared 728 patients with current MDD and 555 non-depressed controls regarding odor identification impairment taking into account the severity of acute symptoms and of the disease course. We assessed current symptom severity with the Hamilton Depression Rating Scale, and disease course severity based on admission diagnosis (ICD-10, F32/F33) and self-reported hospitalization frequency, defined as infrequent (<2) and frequent (≥2) depression-related hospitalizations under constant disease duration. A score of <10 on the Sniffin' Sticks-Screen-12 test determined the presence of odor identification impairment. Compared to non-depressed controls patients with frequent (rapidly recurring) hospitalizations had an elevated chance of odor identification impairment, even after adjustment for smell-influencing factors, such as age and smoking, (OR=1.7; 95% CI 1.0-2.9). Patients with recurrent MDD (F33) also had an elevated odds of odor identification impairment compared to those with a first-time episode (F32, OR=1.5; 95% CI 1.0-2.4). In patients with a first-time episode the chance of odor identification impairment increased by 7% with each point increase in the Hamilton Score. Cross-sectional study. Variation in the use of psychotropic medication is a potential bias. Odor identification impairment was evident in MDD patients with first-time high symptom severity and in patients with a severe disease course. Whether odor identification impairment is a marker or mediator of structural and functional brain changes associated with acute or active MDD requires further investigations in longitudinal studies. Copyright © 2016 Elsevier B.V. All rights reserved.

Antennal Transcriptome Analysis of Odorant Reception Genes in the Red Turpentine Beetle (RTB), Dendroctonus valens.

PubMed

Gu, Xiao-Cui; Zhang, Ya-Nan; Kang, Ke; Dong, Shuang-Lin; Zhang, Long-Wa

2015-01-01

The red turpentine beetle (RTB), Dendroctonus valens LeConte (Coleoptera: Curculionidae, Scolytinae), is a destructive invasive pest of conifers which has become the second most important forest pest nationwide in China. Dendroctonus valens is known to use host odors and aggregation pheromones, as well as non-host volatiles, in host location and mass-attack modulation, and thus antennal olfaction is of the utmost importance for the beetles' survival and fitness. However, information on the genes underlying olfaction has been lacking in D. valens. Here, we report the antennal transcriptome of D. valens from next-generation sequencing, with the goal of identifying the olfaction gene repertoire that is involved in D. valens odor-processing. We obtained 51 million reads that were assembled into 61,889 genes, including 39,831 contigs and 22,058 unigenes. In total, we identified 68 novel putative odorant reception genes, including 21 transcripts encoding for putative odorant binding proteins (OBP), six chemosensory proteins (CSP), four sensory neuron membrane proteins (SNMP), 22 odorant receptors (OR), four gustatory receptors (GR), three ionotropic receptors (IR), and eight ionotropic glutamate receptors. We also identified 155 odorant/xenobiotic degradation enzymes from the antennal transcriptome, putatively identified to be involved in olfaction processes including cytochrome P450s, glutathione-S-transferases, and aldehyde dehydrogenase. Predicted protein sequences were compared with counterparts in Tribolium castaneum, Megacyllene caryae, Ips typographus, Dendroctonus ponderosae, and Agrilus planipennis. The antennal transcriptome described here represents the first study of the repertoire of odor processing genes in D. valens. The genes reported here provide a significant addition to the pool of identified olfactory genes in Coleoptera, which might represent novel targets for insect management. The results from our study also will assist with evolutionary analyses of coleopteran olfaction.

Antennal Transcriptome Analysis of Odorant Reception Genes in the Red Turpentine Beetle (RTB), Dendroctonus valens

PubMed Central

Dong, Shuang-Lin; Zhang, Long-Wa

2015-01-01

Background The red turpentine beetle (RTB), Dendroctonus valens LeConte (Coleoptera: Curculionidae, Scolytinae), is a destructive invasive pest of conifers which has become the second most important forest pest nationwide in China. Dendroctonus valens is known to use host odors and aggregation pheromones, as well as non-host volatiles, in host location and mass-attack modulation, and thus antennal olfaction is of the utmost importance for the beetles’ survival and fitness. However, information on the genes underlying olfaction has been lacking in D. valens. Here, we report the antennal transcriptome of D. valens from next-generation sequencing, with the goal of identifying the olfaction gene repertoire that is involved in D. valens odor-processing. Results We obtained 51 million reads that were assembled into 61,889 genes, including 39,831 contigs and 22,058 unigenes. In total, we identified 68 novel putative odorant reception genes, including 21 transcripts encoding for putative odorant binding proteins (OBP), six chemosensory proteins (CSP), four sensory neuron membrane proteins (SNMP), 22 odorant receptors (OR), four gustatory receptors (GR), three ionotropic receptors (IR), and eight ionotropic glutamate receptors. We also identified 155 odorant/xenobiotic degradation enzymes from the antennal transcriptome, putatively identified to be involved in olfaction processes including cytochrome P450s, glutathione-S-transferases, and aldehyde dehydrogenase. Predicted protein sequences were compared with counterparts in Tribolium castaneum, Megacyllene caryae, Ips typographus, Dendroctonus ponderosae, and Agrilus planipennis. Conclusion The antennal transcriptome described here represents the first study of the repertoire of odor processing genes in D. valens. The genes reported here provide a significant addition to the pool of identified olfactory genes in Coleoptera, which might represent novel targets for insect management. The results from our study also will assist with evolutionary analyses of coleopteran olfaction. PMID:25938508

Contribution of DA Signaling to Appetitive Odor Perception in a Drosophila Model.

PubMed

Pu, Yuhan; Palombo, Melissa Megan Masserant; Shen, Ping

2018-04-13

Understanding cognitive processes that translate chemically diverse olfactory stimuli to specific appetitive drives remains challenging. We have shown that food-related odors arouse impulsive-like feeding of food media that are palatable and readily accessible in well-nourished Drosophila larvae. Here we provide evidence that two assemblies of four dopamine (DA) neurons, one per brain hemisphere, contribute to perceptual processing of the qualitative and quantitative attributes of food scents. These DA neurons receive neural representations of chemically diverse food-related odors, and their combined neuronal activities become increasingly important as the chemical complexity of an appetizing odor stimulus increases. Furthermore, in each assembly of DA neurons, integrated odor signals are transformed to one-dimensional DA outputs that have no intrinsic reward values. Finally, a genetic analysis has revealed a D1-type DA receptor (Dop1R1)-gated mechanism in neuropeptide Y-like neurons that assigns appetitive significance to selected DA outputs. Our findings suggest that fly larvae provide a useful platform for elucidation of molecular and circuit mechanisms underlying cognitive processing of olfactory and possibly other sensory cues.

Odors and incontinence: What does the nose know?

PubMed

Dalton, Pamela; Maute, Christopher

2018-06-01

The fear of producing malodors that can be detected by others is a daily cause of anxiety for millions of people with incontinence. For many, the risk-whether real or imagined-that leaked waste products will be detectable by odor is sufficiently concerning to result in limitations on many types of activities. However, worry about personal odors can sensitize our olfactory system and cause us to be more aware of odors that may otherwise not be perceptible. In addition, heightened olfactory attention can often lead to odor misattributions, such as when we erroneously identify our body as the source of an odor that may simply be present in the environment. Odors produced by our bodies (endogenous odors) do enjoy a greater access to emotional brain centers and are processed faster than general odors. Here we provide examples from both everyday life and laboratory studies to explain how and why the olfactory system is unique among our sensory systems and how this knowledge can provide insights to our concerns about smell and incontinence and inform the development of products and solutions for incontinence.

Olfactometric determination of the most potent odor-active compounds in salmon muscle (Salmo salar) smoked by using four smoke generation techniques.

PubMed

Varlet, Vincent; Serot, Thierry; Cardinal, Mireille; Knockaert, Camille; Prost, Carole

2007-05-30

The volatile compounds of salmon fillets smoked according to four smoked generation techniques (smoldering, thermostated plates, friction, and liquid smoke) were investigated. The main odor-active compounds were identified by gas chromatography coupled with olfactometry and mass spectrometry. Only the odorant volatile compounds detected by at least six judges (out of eight) were identified as potent odorants. Phenolic compounds and guaiacol derivatives were the most detected compounds in the olfactometric profile whatever the smoking process and could constitute the smoky odorant skeleton of these products. They were recovered in the aromatic extracts of salmon smoked by smoldering and by friction, which were characterized by 18 and 25 odor-active compounds, respectively. Furannic compounds were more detected in products smoked with thermostated plates characterized by 26 odorants compounds. Finally, the 27 odorants of products treated with liquid smoke were significantly different from the three others techniques applying wood pyrolysis because pyridine derivatives and lipid oxidation products were perceived in the aroma profile.

Distributions of four taste and odor compounds in the sediment and overlying water at different ecology environment in Taihu Lake.

PubMed

Huang, Heyong; Xu, Xiaoguang; Liu, Xiansheng; Han, Ruiming; Liu, Jine; Wang, Guoxiang

2018-04-18

Organic matter-induced black blooms, such as cyanobacterial and vegetation blooms, are a serious ecosystem disasters that have occurred in Taihu Lake. After large-scale outbreaks of blooms in eutrophic water, a large number of cyanobacterial and vegetation residue accumulate in the coastal areas, and rapidly fermented into odorous compounds. In this study, four taste and odor compounds have been analyzed in sediments and overlying water of different ecology environment in Taihu Lake. High concentrations of DMDS (up to 7165.25 ngg -1  dw -1 ), DMTS (up to 50.93 ngg -1  dw -1 ), β-cyclocitral (up to 5441.69 ngg -1  dw -1 ), β-ionone (up to 1669.37 ngg -1  dw -1 ) were detected in sediments. Also, the spatial distributions of DMDS, DMTS, β-cyclocitral and β-ionone in the sediments were investigated. As the depth of sediment increases, nutrients and odorous compounds are greatly reduced. The results showed that during the degradation of cyanobacterial and vegetation residues, DMDS, DMTS, β-cyclocitral, β-ionone and nutrients are gradually released. In addition, when assessing the source of odorous compounds in overlying water, it should also be considered that it may be released from the sediment. This study shows that odorous compounds are ubiquitous in near-shore zones Taihu Lake, and may take potential hazard to aquatic ecosystems.

Minimal olfactory perception during sleep: why odor alarms will not work for humans.

PubMed

Carskadon, Mary A; Herz, Rachel S

2004-05-01

To examine olfactory arousal threshold during sleep in comparison to an auditory tone. On night 1, participants rated odor intensity when awake and experienced olfactory stimuli during stage 1 sleep. Night 2 involved stage 2, stage 4, and rapid-eye-movement (REM) sleep trials using the "staircase" threshold-detection method. Electroencephalogram, electrooculogram, electromyogram, electrocardiogram, and respiration were recorded along with behavioral response. An 800-Hz tone was given on trials when odors failed to arouse. Participants slept in individual rooms. Stimulus-delivery systems were operated from a separate room, where an experimenter observed physiologic recordings and behavioral responses. Three healthy men and 3 women aged 20 to 25 years (mean, 22 years). Two odorants, peppermint and pyridine, at 4 concentrations were presented through nasal cannulas using an air-dilution olfactometer. Tones were played over a speaker. Behavioral (button press and oral) responses, electroencephalographic activation, and changes in breathing and heart rate were assessed. Participants responded to odors on 92% of stage 1 sleep trials. Peppermint was ineffective in stages 2, 4, and REM sleep. Pyridine produced behavioral threshold on 45% of stage 2 trials, none in stage 4, and one third of REM sleep trials. Tones were effective on at least 75% of trials. Heart rate increased significantly only following behavioral responses to odors or tones across sleep stages. The data indicate that human olfaction is not reliably capable of alerting a sleeper.

Proceedings of Tripartite Conference on Submarine Medicine and IEP B-52 - France, United Kingdom, United States (6th) Held in Groton, Connecticut on 1-4 June 1987

DTIC Science & Technology

1990-10-03

stored and statistical profiles generated on 20-36 compounds of most interest. The list of priority compounds could be readily changed. Mr. Thill...a propellant gas. Calculations showed that atmospheric dilution would be rapid. Tests showed that the compound was very stable in the atmosphere...ppm (less methane) Particulates/mist : < 5 mg/cu.m. Odor : Not objectionable Thousands of samples are processed every year and the failure rate is low

Molecular Basis of Olfactory Chemoreception in the Common Bed Bug, Cimex lectularius

PubMed Central

Liu, Feng; Chen, Zhou; Liu, Nannan

2017-01-01

As one of the most notorious ectoparasites, bed bugs rely heavily on human or animal blood sources for survival, mating and reproduction. Chemoreception, mediated by the odorant receptors on the membrane of olfactory sensory neurons, plays a vital role in their host seeking and risk aversion processes. We investigated the responses of odorant receptors to a large spectrum of semiochemicals, including human odorants and plant-released volatiles and found that strong responses were sparse; aldehydes/ketones were the most efficient stimuli, while carboxylic acids and aliphatics/aromatics were comparatively less effective in eliciting responses from bed bug odorant receptors. In bed bugs, both the odorant identity and concentrations play important roles in determining the strength of these responses. The odor space constructed based on the responses from all the odorant receptors tested revealed that odorants within the same chemical group are widely dispersed while odorants from different groups are intermingled, suggesting the complexity of odorant encoding in the bed bug odorant receptors. This study provides a comprehensive picture of the olfactory coding mechanisms of bed bugs that will ultimately contribute to the design and development of novel olfactory-based strategies to reduce both the biting nuisance and disease transmission from bed bugs. PMID:28383033

Modulatory Effects of Sex Steroids Progesterone and Estradiol on Odorant Evoked Responses in Olfactory Receptor Neurons

PubMed Central

Scholz, Paul; Mohrhardt, Julia; Gisselmann, Günter; Hatt, Hanns

2016-01-01

The influence of the sex steroid hormones progesterone and estradiol on physiology and behavior during menstrual cycles and pregnancy is well known. Several studies indicate that olfactory performance changes with cyclically fluctuating steroid hormone levels in females. Knowledge of the exact mechanisms behind how female sex steroids modulate olfactory signaling is limited. A number of different known genomic and non-genomic actions that are mediated by progesterone and estradiol via interactions with different receptors may be responsible for this modulation. Next generation sequencing-based RNA-Seq transcriptome data from the murine olfactory epithelium (OE) and olfactory receptor neurons (ORNs) revealed the expression of several membrane progestin receptors and the estradiol receptor Gpr30. These receptors are known to mediate rapid non-genomic effects through interactions with G proteins. RT-PCR and immunohistochemical staining results provide evidence for progestin and estradiol receptors in the ORNs. These data support the hypothesis that steroid hormones are capable of modulating the odorant-evoked activity of ORNs. Here, we validated this hypothesis through the investigation of steroid hormone effects by submerged electro-olfactogram and whole cell patch-clamp recordings of ORNs. For the first time, we demonstrate that the sex steroid hormones progesterone and estradiol decrease odorant-evoked signals in the OE and ORNs of mice at low nanomolar concentrations. Thus, both of these sex steroids can rapidly modulate the odor responsiveness of ORNs through membrane progestin receptors and the estradiol receptor Gpr30. PMID:27494699

"Imposed" and "inherent" mucosal activity patterns. Their composite representation of olfactory stimuli

PubMed Central

1987-01-01

Both regional differences in mucosal sensitivity and a gas chromatography-like process along the mucosal sheet have been separately proposed in two sets of earlier studies to produce different odorant-dependent activity patterns across the olfactory mucosa. This investigation evaluated, in one study, whether and to what degree these two mechanisms contribute to the generation of these activity patterns. Summated multiunit discharges were simultaneously recorded from lateral (LN) and medial (MN) sites on the bullfrog's olfactory nerve to sample the mucosal activity occurring near the internal and external nares, respectively. Precisely controlled sniffs of four odorants (benzaldehyde, butanol, geraniol, and octane) were drawn through the frog's olfactory sac in both the forward (H1) and reverse (H2) hale directions. By combining the four resulting measurements, LNH1, LNH2, MNH1, and MNH2, in different mathematical expressions, indexes reflecting the relative effects of the chromatographic process, regional sensitivity, and hale direction could be calculated. Most importantly, the chromatographic process and the regional sensitivity differences both contributed significantly to the mucosal activity patterns. However, their relative roles varied markedly among the four odorants, ranging from complete dominance by either one to substantial contributions from each. In general, the more strongly an odorant was sorbed by the mucosa, the greater was the relative effect of the chromatographic process; the weaker the sorption, the greater the relative effect of regional sensitivity. Similarly, the greater an odorant's sorption, the greater was the effect of hale direction. Other stimulus variables (sniff volume, sniff duration, and the number of molecules within the sniff) had marked effects upon the overall size of the response. For strongly sorbed odorants, the effect of increasing volume was positive; for a weakly sorbed odorant, it was negative. The reverse may be true for duration. In contrast, the effect of increasing the number of molecules was uniformly positive for all four odorants. However, there was little evidence that these other stimulus variables had a major influence upon the effects of the chromatographic process and regional sensitivity differences in their generation of mucosal activity patterns. PMID:3500998

Identification of Odor-Processing Genes in the Emerald Ash Borer, Agrilus planipennis

PubMed Central

Mamidala, Praveen; Wijeratne, Asela J.; Wijeratne, Saranga; Poland, Therese; Qazi, Sohail S.; Doucet, Daniel; Cusson, Michel; Beliveau, Catherine; Mittapalli, Omprakash

2013-01-01

Background Insects rely on olfaction to locate food, mates, and suitable oviposition sites for successful completion of their life cycle. Agrilus planipennis Fairmaire (emerald ash borer) is a serious invasive insect pest that has killed tens of millions of North American ash (Fraxinus spp) trees and threatens the very existence of the genus Fraxinus. Adult A. planipennis are attracted to host volatiles and conspecifics; however, to date no molecular knowledge exists on olfaction in A. planipennis. Hence, we undertook an antennae-specific transcriptomic study to identify the repertoire of odor processing genes involved in A. planipennis olfaction. Methodology and Principal Findings We acquired 139,085 Roche/454 GS FLX transcriptomic reads that were assembled into 30,615 high quality expressed sequence tags (ESTs), including 3,249 isotigs and 27,366 non-isotigs (contigs and singletons). Intriguingly, the majority of the A. planipennis antennal transcripts (59.72%) did not show similarity with sequences deposited in the non-redundant database of GenBank, potentially representing novel genes. Functional annotation and KEGG analysis revealed pathways associated with signaling and detoxification. Several odor processing genes (9 odorant binding proteins, 2 odorant receptors, 1 sensory neuron membrane protein and 134 odorant/xenobiotic degradation enzymes, including cytochrome P450s, glutathione-S-transferases; esterases, etc.) putatively involved in olfaction processes were identified. Quantitative PCR of candidate genes in male and female A. planipennis in different developmental stages revealed developmental- and sex-biased expression patterns. Conclusions and Significance The antennal ESTs derived from A. planipennis constitute a rich molecular resource for the identification of genes potentially involved in the olfaction process of A. planipennis. These findings should help in understanding the processing of antennally-active compounds (e.g. 7-epi-sesquithujene) previously identified in this serious invasive pest. PMID:23424668

Identification of odor-processing genes in the emerald ash borer, Agrilus planipennis.

PubMed

Mamidala, Praveen; Wijeratne, Asela J; Wijeratne, Saranga; Poland, Therese; Qazi, Sohail S; Doucet, Daniel; Cusson, Michel; Beliveau, Catherine; Mittapalli, Omprakash

2013-01-01

Insects rely on olfaction to locate food, mates, and suitable oviposition sites for successful completion of their life cycle. Agrilus planipennis Fairmaire (emerald ash borer) is a serious invasive insect pest that has killed tens of millions of North American ash (Fraxinus spp) trees and threatens the very existence of the genus Fraxinus. Adult A. planipennis are attracted to host volatiles and conspecifics; however, to date no molecular knowledge exists on olfaction in A. planipennis. Hence, we undertook an antennae-specific transcriptomic study to identify the repertoire of odor processing genes involved in A. planipennis olfaction. We acquired 139,085 Roche/454 GS FLX transcriptomic reads that were assembled into 30,615 high quality expressed sequence tags (ESTs), including 3,249 isotigs and 27,366 non-isotigs (contigs and singletons). Intriguingly, the majority of the A. planipennis antennal transcripts (59.72%) did not show similarity with sequences deposited in the non-redundant database of GenBank, potentially representing novel genes. Functional annotation and KEGG analysis revealed pathways associated with signaling and detoxification. Several odor processing genes (9 odorant binding proteins, 2 odorant receptors, 1 sensory neuron membrane protein and 134 odorant/xenobiotic degradation enzymes, including cytochrome P450s, glutathione-S-transferases; esterases, etc.) putatively involved in olfaction processes were identified. Quantitative PCR of candidate genes in male and female A. planipennis in different developmental stages revealed developmental- and sex-biased expression patterns. The antennal ESTs derived from A. planipennis constitute a rich molecular resource for the identification of genes potentially involved in the olfaction process of A. planipennis. These findings should help in understanding the processing of antennally-active compounds (e.g. 7-epi-sesquithujene) previously identified in this serious invasive pest.

Parallel Olfactory Processing in the Honey Bee Brain: Odor Learning and Generalization under Selective Lesion of a Projection Neuron Tract

PubMed Central

Carcaud, Julie; Giurfa, Martin; Sandoz, Jean Christophe

2016-01-01

The function of parallel neural processing is a fundamental problem in Neuroscience, as it is found across sensory modalities and evolutionary lineages, from insects to humans. Recently, parallel processing has attracted increased attention in the olfactory domain, with the demonstration in both insects and mammals that different populations of second-order neurons encode and/or process odorant information differently. Among insects, Hymenoptera present a striking olfactory system with a clear neural dichotomy from the periphery to higher-order centers, based on two main tracts of second-order (projection) neurons: the medial and lateral antennal lobe tracts (m-ALT and l-ALT). To unravel the functional role of these two pathways, we combined specific lesions of the m-ALT tract with behavioral experiments, using the classical conditioning of the proboscis extension response (PER conditioning). Lesioned and intact bees had to learn to associate an odorant (1-nonanol) with sucrose. Then the bees were subjected to a generalization procedure with a range of odorants differing in terms of their carbon chain length or functional group. We show that m-ALT lesion strongly affects acquisition of an odor-sucrose association. However, lesioned bees that still learned the association showed a normal gradient of decreasing generalization responses to increasingly dissimilar odorants. Generalization responses could be predicted to some extent by in vivo calcium imaging recordings of l-ALT neurons. The m-ALT pathway therefore seems necessary for normal classical olfactory conditioning performance. PMID:26834589

Good morning creativity: task reactivation during sleep enhances beneficial effect of sleep on creative performance.

PubMed

Ritter, Simone M; Strick, Madelijn; Bos, Maarten W; van Baaren, Rick B; Dijksterhuis, Ap

2012-12-01

Both scientists and artists have suggested that sleep facilitates creativity, and this idea has received substantial empirical support. In the current study, we investigate whether one can actively enhance the beneficial effect of sleep on creativity by covertly reactivating the creativity task during sleep. Individuals' creative performance was compared after three different conditions: sleep-with-conditioned-odor; sleep-with-control-odor; or sleep-with-no-odor. In the evening prior to sleep, all participants were presented with a problem that required a creative solution. In the two odor conditions, a hidden scent-diffuser spread an odor while the problem was presented. In the sleep-with-conditioned-odor condition, task reactivation during sleep was induced by means of the odor that was also presented while participants were informed about the problem. In the sleep-with-control-odor condition, participants were exposed to a different odor during sleep than the one diffused during problem presentation. In the no odor condition, no odor was presented. After a night of sleep with the conditioned odor, participants were found to be: (i) more creative; and (ii) better able to select their most creative idea than participants who had been exposed to a control odor or no odor while sleeping. These findings suggest that we do not have to passively wait until we are hit by our creative muse while sleeping. Task reactivation during sleep can actively trigger creativity-related processes during sleep and thereby boost the beneficial effect of sleep on creativity. © 2012 European Sleep Research Society.

Volatile organic compound flux from manure of cattle fed diets differing in grain processing method and co-product inclusion

USDA-ARS?s Scientific Manuscript database

Odor emissions from livestock production have become increasingly important in the past decade. Odors derived from animal feeding operations are caused by odorous VOC emitted from the mixture of feces and urine, as well as feed and silage which may be experiencing microbial fermentation. Distiller...

Processes to Preserve Spice and Herb Quality and Sensory Integrity During Pathogen Inactivation

PubMed Central

Moberg, Kayla; Amin, Kemia N.; Wright, Melissa; Newkirk, Jordan J.; Ponder, Monica A.; Acuff, Gary R.; Dickson, James S.

2017-01-01

Abstract Selected processing methods, demonstrated to be effective at reducing Salmonella, were assessed to determine if spice and herb quality was affected. Black peppercorn, cumin seed, oregano, and onion powder were irradiated to a target dose of 8 kGy. Two additional processes were examined for whole black peppercorns and cumin seeds: ethylene oxide (EtO) fumigation and vacuum assisted‐steam (82.22 °C, 7.5 psia). Treated and untreated spices/herbs were compared (visual, odor) using sensory similarity testing protocols (α = 0.20; β = 0.05; proportion of discriminators: 20%) to determine if processing altered sensory quality. Analytical assessment of quality (color, water activity, and volatile chemistry) was completed. Irradiation did not alter visual or odor sensory quality of black peppercorn, cumin seed, or oregano but created differences in onion powder, which was lighter (higher L *) and more red (higher a*) in color, and resulted in nearly complete loss of measured volatile compounds. EtO processing did not create detectable odor or appearance differences in black peppercorn; however visual and odor sensory quality differences, supported by changes in color (higher b *; lower L *) and increased concentrations of most volatiles, were detected for cumin seeds. Steam processing of black peppercorn resulted in perceptible odor differences, supported by increased concentration of monoterpene volatiles and loss of all sesquiterpenes; only visual differences were noted for cumin seed. An important step in process validation is the verification that no effect is detectable from a sensory perspective. PMID:28407236

Functional magnetic resonance imaging in awake transgenic fragile X rats: evidence of dysregulation in reward processing in the mesolimbic/habenular neural circuit.

PubMed

Kenkel, W M; Yee, J R; Moore, K; Madularu, D; Kulkarni, P; Gamber, K; Nedelman, M; Ferris, C F

2016-03-22

Anxiety and social deficits, often involving communication impairment, are fundamental clinical features of fragile X syndrome. There is growing evidence that dysregulation in reward processing is a contributing factor to the social deficits observed in many psychiatric disorders. Hence, we hypothesized that transgenic fragile X mental retardation 1 gene (fmr1) KO (FX) rats would display alterations in reward processing. To this end, awake control and FX rats were imaged for changes in blood oxygen level dependent (BOLD) signal intensity in response to the odor of almond, a stimulus to elicit the innate reward response. Subjects were 'odor naive' to this evolutionarily conserved stimulus. The resulting changes in brain activity were registered to a three-dimensional segmented, annotated rat atlas delineating 171 brain regions. Both wild-type (WT) and FX rats showed robust brain activation to a rewarding almond odor, though FX rats showed an altered temporal pattern and tended to have a higher number of voxels with negative BOLD signal change from baseline. This pattern of greater negative BOLD was especially apparent in the Papez circuit, critical to emotional processing and the mesolimbic/habenular reward circuit. WT rats showed greater positive BOLD response in the supramammillary area, whereas FX rats showed greater positive BOLD response in the dorsal lateral striatum, and greater negative BOLD response in the retrosplenial cortices, the core of the accumbens and the lateral preoptic area. When tested in a freely behaving odor-investigation paradigm, FX rats failed to show the preference for almond odor which typifies WT rats. However, FX rats showed investigation profiles similar to WT when presented with social odors. These data speak to an altered processing of this highly salient novel odor in the FX phenotype and lend further support to the notion that altered reward systems in the brain may contribute to fragile X syndrome symptomology.

A comparison of methods for the assessment of odor impacts on air quality: Field inspection (VDI 3940) and the air dispersion model CALPUFF

NASA Astrophysics Data System (ADS)

Ranzato, Laura; Barausse, Alberto; Mantovani, Alice; Pittarello, Alberto; Benzo, Maurizio; Palmeri, Luca

2012-12-01

Unpleasant odors are a major cause of public complaints concerning air quality and represent a growing social problem in industrialized countries. However, the assessment of odor pollution is still regarded as a difficult task, because olfactory nuisance can be caused by many different chemical compounds, often found in hard-to-detect concentrations, and the perception of odors is influenced by subjective thresholds; moreover, the impact of odor sources on air quality is mediated by complex atmospheric dispersion processes. The development of standardized assessment approaches to odor pollution and proper international regulatory tools are urgently needed. In particular, comparisons of the methodologies commonly used nowadays to assess odor impacts on air quality are required. Here, we assess the olfactory nuisance caused by an anaerobic treatment plant for municipal solid waste by means of two alternative techniques: the field inspection procedure and the atmospheric dispersion model CALPUFF. Our goal was to compare rigorously their estimates of odor nuisance, both qualitatively (spatial extent of odor impact) and quantitatively (intensity of odor nuisance). To define the impact of odors, we referred to the German standards, based on the frequency of odor episodes in terms of odor hours. We report a satisfying, although not perfect agreement between the estimates provided by the two techniques. For example, they assessed similar spatial extents of odor pollution, but different frequencies of odor episodes in locations where the odor nuisance was highest. The comparison highlights strengths and weaknesses for both approaches. CALPUFF is a cheaper methodology which can be used predictively, but fugitive emissions are difficult to model reliably, because of uncertainty regarding timing, location and emission rate. Field inspection takes into account the role of human perception, but unlike the model it does not always characterize precisely the extent of the odor nuisance caused by a single source when other odors are present, because only the most unpleasant odor is reported. We conclude that these two assessment methods provide reasonable estimates of odor nuisance.

Pharmacological Analysis of Ionotropic Glutamate Receptor Function in Neuronal Circuits of the Zebrafish Olfactory Bulb

PubMed Central

Tabor, Rico; Friedrich, Rainer W.

2008-01-01

Although synaptic functions of ionotropic glutamate receptors in the olfactory bulb have been studied in vitro, their roles in pattern processing in the intact system remain controversial. We therefore examined the functions of ionotropic glutamate receptors during odor processing in the intact olfactory bulb of zebrafish using pharmacological manipulations. Odor responses of mitral cells and interneurons were recorded by electrophysiology and 2-photon Ca2+ imaging. The combined blockade of AMPA/kainate and NMDA receptors abolished odor-evoked excitation of mitral cells. The blockade of AMPA/kainate receptors alone, in contrast, increased the mean response of mitral cells and decreased the mean response of interneurons. The blockade of NMDA receptors caused little or no change in the mean responses of mitral cells and interneurons. However, antagonists of both receptor types had diverse effects on the magnitude and time course of individual mitral cell and interneuron responses and, thus, changed spatio-temporal activity patterns across neuronal populations. Oscillatory synchronization was abolished or reduced by AMPA/kainate and NMDA receptor antagonists, respectively. These results indicate that (1) interneuron responses depend mainly on AMPA/kainate receptor input during an odor response, (2) interactions among mitral cells and interneurons regulate the total olfactory bulb output activity, (3) AMPA/kainate receptors participate in the synchronization of odor-dependent neuronal ensembles, and (4) ionotropic glutamate receptor-containing synaptic circuits shape odor-specific patterns of olfactory bulb output activity. These mechanisms are likely to be important for the processing of odor-encoding activity patterns in the olfactory bulb. PMID:18183297

Neurobehavioral assessment of maternal odor in developing rat pups: implications for social buffering.

PubMed

Al Aïn, Syrina; Perry, Rosemarie E; Nuñez, Bestina; Kayser, Kassandra; Hochman, Chase; Brehman, Elizabeth; LaComb, Miranda; Wilson, Donald A; Sullivan, Regina M

2017-02-01

Social support can attenuate the behavioral and stress hormone response to threat, a phenomenon called social buffering. The mother's social buffering of the infant is one of the more robust examples; yet we understand little about the neurobiology. Using a rodent model, we explore the neurobiology of social buffering by assessing neural processing of the maternal odor, a major cue controlling social buffering in rat pups. We used pups before (postnatal day (PN) 7) and after (PN14, PN23) the functional emergence of social buffering. Pups were injected with 14 C 2-deoxyglucose (2-DG) and presented with the maternal odor, a control preferred odor incapable of social buffering (acetophenone), or no odor. Brains were removed, processed for autoradiography and brain areas identified as important in adult social buffering were assessed, including the amygdala basolateral complex (Basolateral Amygdala [BLA]), medial prefrontal cortex (mPFC), and anterior cingulate cortex (ACC). Results suggest dramatic changes in the processing of maternal odor. PN7 pups show mPFC and ACC activation, although PN14 pups showed no activation of the mPFC, ACC, or BLA. All brain areas assessed were recruited by PN23. Additional analysis suggests substantial changes in functional connectivity across development. Together, these results imply complex nonlinear transitions in the neurobiology of social buffering in early life that may provide insight into the changing role of the mother in supporting social buffering.

From Nose to Memory: The Involuntary Nature of Odor-evoked Autobiographical Memories in Alzheimer's Disease.

PubMed

El Haj, Mohamad; Gandolphe, Marie Charlotte; Gallouj, Karim; Kapogiannis, Dimitrios; Antoine, Pascal

2017-12-25

Research suggests that odors may serve as a potent cue for autobiographical retrieval. We tested this hypothesis in Alzheimer's disease (AD) and investigated whether odor-evoked autobiographical memory is an involuntary process that shares similarities with music-evoked autobiographical memory. Participants with mild AD and controls were asked to retrieve 2 personal memories after odor exposure, after music exposure, and in an odor-and music-free condition. AD participants showed better specificity, emotional experience, mental time travel, and retrieval time after odor and music exposure than in the control condition. Similar beneficial effects of odor and music exposure were observed for autobiographical characteristics (i.e., specificity, emotional experience, and mental time travel), except for retrieval time which was more improved after odor than after music exposure. Interestingly, regression analyses suggested executive involvement in memories evoked in the control condition but not in those evoked after music or odor exposure. These findings suggest the involuntary nature of odor-evoked autobiographical memory in AD. They also suggest that olfactory cuing could serve as a useful and ecologically valid tool to stimulate autobiographical memory, at least in the mild stage of the disease. © The Author(s) 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Differential associative training enhances olfactory acuity in Drosophila melanogaster.

PubMed

Barth, Jonas; Dipt, Shubham; Pech, Ulrike; Hermann, Moritz; Riemensperger, Thomas; Fiala, André

2014-01-29

Training can improve the ability to discriminate between similar, confusable stimuli, including odors. One possibility of enhancing behaviorally expressed discrimination (i.e., sensory acuity) relies on differential associative learning, during which animals are forced to detect the differences between similar stimuli. Drosophila represents a key model organism for analyzing neuronal mechanisms underlying both odor processing and olfactory learning. However, the ability of flies to enhance fine discrimination between similar odors through differential associative learning has not been analyzed in detail. We performed associative conditioning experiments using chemically similar odorants that we show to evoke overlapping neuronal activity in the fly's antennal lobes and highly correlated activity in mushroom body lobes. We compared the animals' performance in discriminating between these odors after subjecting them to one of two types of training: either absolute conditioning, in which only one odor is reinforced, or differential conditioning, in which one odor is reinforced and a second odor is explicitly not reinforced. First, we show that differential conditioning decreases behavioral generalization of similar odorants in a choice situation. Second, we demonstrate that this learned enhancement in olfactory acuity relies on both conditioned excitation and conditioned inhibition. Third, inhibitory local interneurons in the antennal lobes are shown to be required for behavioral fine discrimination between the two similar odors. Fourth, differential, but not absolute, training causes decorrelation of odor representations in the mushroom body. In conclusion, differential training with similar odors ultimately induces a behaviorally expressed contrast enhancement between the two similar stimuli that facilitates fine discrimination.

Complex Odor from Plants under Attack: Herbivore's Enemies React to the Whole, Not Its Parts

PubMed Central

van Wijk, Michiel; de Bruijn, Paulien J. A.; Sabelis, Maurice W.

2011-01-01

Background Insect herbivory induces plant odors that attract herbivores' natural enemies. Assuming this attraction emerges from individual compounds, genetic control over odor emission of crops may provide a rationale for manipulating the distribution of predators used for pest control. However, studies on odor perception in vertebrates and invertebrates suggest that olfactory information processing of mixtures results in odor percepts that are a synthetic whole and not a set of components that could function as recognizable individual attractants. Here, we ask if predators respond to herbivore-induced attractants in odor mixtures or to odor mixture as a whole. Methodology/Principal Findings We studied a system consisting of Lima bean, the herbivorous mite Tetranychus urticae and the predatory mite Phytoseiulus persimilis. We found that four herbivore-induced bean volatiles are not attractive in pure form while a fifth, methyl salicylate (MeSA), is. Several reduced mixtures deficient in one component compared to the full spider-mite induced blend were not attractive despite the presence of MeSA indicating that the predators cannot detect this component in these odor mixtures. A mixture of all five HIPV is most attractive, when offered together with the non-induced odor of Lima bean. Odors that elicit no response in their pure form were essential components of the attractive mixture. Conclusions/Significance We conclude that the predatory mites perceive odors as a synthetic whole and that the hypothesis that predatory mites recognize attractive HIPV in odor mixtures is unsupported. PMID:21765908

Context odor presentation during sleep enhances memory in honeybees.

PubMed

Zwaka, Hanna; Bartels, Ruth; Gora, Jacob; Franck, Vivien; Culo, Ana; Götsch, Moritz; Menzel, Randolf

2015-11-02

Sleep plays an important role in stabilizing new memory traces after learning [1-3]. Here we investigate whether sleep's role in memory processing is similar in evolutionarily distant species and demonstrate that a context trigger during deep-sleep phases improves memory in invertebrates, as it does in humans. We show that in honeybees (Apis mellifera), exposure to an odor during deep sleep that has been present during learning improves memory performance the following day. Presentation of the context odor during wake phases or novel odors during sleep does not enhance memory. In humans, memory consolidation can be triggered by presentation of a context odor during slow-wave sleep that had been present during learning [3-5]. Our results reveal that deep-sleep phases in honeybees have the potential to prompt memory consolidation, just as they do in humans. This study provides strong evidence for a conserved role of sleep-and how it affects memory processes-from insects to mammals. Copyright © 2015 Elsevier Ltd. All rights reserved.

Visualizing mushroom body response to a conditioned odor in honeybees

NASA Astrophysics Data System (ADS)

Faber, Till; Menzel, Randolf

2001-11-01

Combining differential conditioning with optophysiological recordings of bee brain activity allows the investigation of learning-related changes in complex neural systems. In this study we focused on the mushroom bodies of the bee brain. Presenting different odors to the animal leads to significant activation of the mushroom body lips. After differential conditioning, the rewarded odor leads to stronger activation than it did before training. Activation by the unrewarded odor remains unchanged. These results resemble findings in the bee's antennal lobes, which are the first olfactory relay station in the insect brain. As an integrative neural network, enhanced activation of the mushroom body lip may carry additional information, i.e., for processing odor concentrations.

Endogenous oxytocin is necessary for preferential Fos expression to male odors in the bed nucleus of the stria terminalis in female Syrian hamsters.

PubMed

Martinez, Luis A; Levy, Marisa J; Petrulis, Aras

2013-09-01

Successful reproduction in mammals depends on proceptive or solicitational behaviors that enhance the probability of encountering potential mates. In female Syrian hamsters, one such behavior is vaginal scent marking. Recent evidence suggests that the neuropeptide oxytocin (OT) may be critical for regulating this behavior. Blockade of OT receptors in the bed nucleus of the stria terminalis (BNST) or the medial preoptic area (MPOA) decreases vaginal marking responses to male odors; lesion data suggest that BNST, rather than MPOA, mediates this effect. However, how OT interacts with sexual odor processing to drive preferential solicitation is not known. To address this issue, intact female Syrian hamsters were exposed to male or female odors and their brains processed for immunohistochemistry for Fos, a marker of recent neuronal activation, and OT. Additional females were injected intracerebroventricularly (ICV) with an oxytocin receptor antagonist (OTA) or vehicle, and then tested for vaginal marking and Fos responses to sexual odors. Colocalization of OT and Fos in the paraventricular nucleus of the hypothalamus was unchanged following exposure to male odors, but decreased following exposure to female odors. Following injections of OTA, Fos expression to male odors was decreased in BNST, but not in MPOA or the medial amygdala (MA). Fos expression in BNST may be functionally relevant for vaginal marking, given that there was a positive correlation between Fos expression and vaginal marking for BNST, but not MPOA or MA. Together, these data suggest that OT facilitation of neuronal activity in BNST underlies the facilitative effects of OT on solicitational responses to male odors. © 2013.

Odor composition analysis and odor indicator selection during sewage sludge composting

PubMed Central

Zhu, Yan-li; Zheng, Guo-di; Gao, Ding; Chen, Tong-bin; Wu, Fang-kun; Niu, Ming-jie; Zou, Ke-hua

2016-01-01

ABSTRACT On the basis of total temperature increase, normal dehydration, and maturity, the odor compositions of surface and internal piles in a well-run sewage sludge compost plant were analyzed using gas chromatography–mass spectrometry with a liquid nitrogen cooling system and a portable odor detector. Approximately 80 types of substances were detected, including 2 volatile inorganic compounds, 4 sulfur organic compounds, 16 benzenes, 27 alkanes, 15 alkenes, and 19 halogenated compounds. Most pollutants were mainly produced in the mesophilic and pre-thermophilic periods. The sulfur volatile organic compounds contributed significantly to odor and should be controlled primarily. Treatment strategies should be based on the properties of sulfur organic compounds. Hydrogen sulfide, methyl mercaptan, dimethyl disulfide, dimethyl sulfide, ammonia, and carbon disulfide were selected as core indicators. Ammonia, hydrogen sulfide, carbon disulfide, dimethyl disulfide, methyl mercaptan, dimethylbenzene, phenylpropane, and isopentane were designated as concentration indicators. Benzene, m-xylene, p-xylene, dimethylbenzene, dichloromethane, toluene, chlorobenzene, trichloromethane, carbon tetrachloride, and ethylbenzene were selected as health indicators. According to the principle of odor pollution indicator selection, dimethyl disulfide was selected as an odor pollution indicator of sewage sludge composting. Monitoring dimethyl disulfide provides a highly scientific method for modeling and evaluating odor pollution from sewage sludge composting facilities. Implications: Composting is one of the most important methods for sewage sludge treatment and improving the low organic matter content of many agricultural soils. However, odors are inevitably produced during the composting process. Understanding the production and emission patterns of odors is important for odor control and treatment. Core indicators, concentration indicators, and health indicators provide an index system to odor evaluation. An odor pollution indicator provides theoretical support for further modelling and evaluating odor pollution from sewage sludge composting facilities. PMID:27192607

Odor composition analysis and odor indicator selection during sewage sludge composting.

PubMed

Zhu, Yan-Li; Zheng, Guo-di; Gao, Ding; Chen, Tong-Bin; Wu, Fang-Kun; Niu, Ming-Jie; Zou, Ke-Hua

2016-09-01

On the basis of total temperature increase, normal dehydration, and maturity, the odor compositions of surface and internal piles in a well-run sewage sludge compost plant were analyzed using gas chromatography-mass spectrometry with a liquid nitrogen cooling system and a portable odor detector. Approximately 80 types of substances were detected, including 2 volatile inorganic compounds, 4 sulfur organic compounds, 16 benzenes, 27 alkanes, 15 alkenes, and 19 halogenated compounds. Most pollutants were mainly produced in the mesophilic and pre-thermophilic periods. The sulfur volatile organic compounds contributed significantly to odor and should be controlled primarily. Treatment strategies should be based on the properties of sulfur organic compounds. Hydrogen sulfide, methyl mercaptan, dimethyl disulfide, dimethyl sulfide, ammonia, and carbon disulfide were selected as core indicators. Ammonia, hydrogen sulfide, carbon disulfide, dimethyl disulfide, methyl mercaptan, dimethylbenzene, phenylpropane, and isopentane were designated as concentration indicators. Benzene, m-xylene, p-xylene, dimethylbenzene, dichloromethane, toluene, chlorobenzene, trichloromethane, carbon tetrachloride, and ethylbenzene were selected as health indicators. According to the principle of odor pollution indicator selection, dimethyl disulfide was selected as an odor pollution indicator of sewage sludge composting. Monitoring dimethyl disulfide provides a highly scientific method for modeling and evaluating odor pollution from sewage sludge composting facilities. Composting is one of the most important methods for sewage sludge treatment and improving the low organic matter content of many agricultural soils. However, odors are inevitably produced during the composting process. Understanding the production and emission patterns of odors is important for odor control and treatment. Core indicators, concentration indicators, and health indicators provide an index system to odor evaluation. An odor pollution indicator provides theoretical support for further modelling and evaluating odor pollution from sewage sludge composting facilities.

Spoilage bacteria of fresh broiler chicken carcasses.

PubMed

Russell, S M; Fletcher, D L; Cox, N A

1995-12-01

Studies were conducted to identify the bacteria responsible for spoilage of fresh broiler chicken carcasses and to characterize the off-odors these bacteria produce. Broiler carcasses were collected from processing plants in the northeast Georgia area, the southeastern U.S., Arkansas, California, and North Carolina. The carcasses were allowed to spoil under controlled conditions at 3 C and spoilage bacteria were isolated. Each spoilage bacterium was separately inoculated into a sterile chicken skin medium, incubated at 25 C for 48 h, and subjectively evaluated for odor. The bacteria isolated from spoiled carcasses that consistently produced off-odors in the chicken skin medium, regardless of the geographical location from which the chickens were obtained, were Shewanella putrefaciens A, B, and D, Pseudomonas fluorescens A, B, and D, and Pseudomonas fragi. These bacteria produced off-odors that resembled "sulfur", "dishrag", "ammonia", "wet dog", "skunk", "dirty socks", "rancid fish", "unspecified bad odor", or a sweet smell resembling "canned corn". Odors produced by the spoilage bacteria were varied; however, odors most associated with spoiled poultry, such as "dishraggy" odors, were produced by the bacteria that were most consistently isolated, such as S. putrefaciens and the pseudomonads.

Cortical Odor Processing in Health and Disease

PubMed Central

Wilson, Donald A.; Xu, Wenjin; Sadrian, Benjamin; Courtiol, Emmanuelle; Cohen, Yaniv; Barnes, Dylan C.

2014-01-01

The olfactory system has a rich cortical representation, including a large archicortical component present in most vertebrates, and in mammals neocortical components including the entorhinal and orbitofrontal cortices. Together, these cortical components contribute to normal odor perception and memory. They help transform the physicochemical features of volatile molecules inhaled or exhaled through the nose into the perception of odor objects with rich associative and hedonic aspects. This chapter focuses on how olfactory cortical areas contribute to odor perception and begins to explore why odor perception is so sensitive to disease and pathology. Odor perception is disrupted by a wide range of disorders including Alzheimer’s disease, Parkinson’s disease, schizophrenia, depression, autism, and early life exposure to toxins. This olfactory deficit often occurs despite maintained functioning in other sensory systems. Does the unusual network of olfactory cortical structures contribute to this sensitivity? PMID:24767487

The study of multiphase flow control during odor reproduction

NASA Astrophysics Data System (ADS)

Luo, Dehan; Yu, Hao; Fan, Danjun; He, Meiqiu

2014-04-01

Odor reproduction, is the use of the chemical composition of the basic components of odor recipe, according to a certain proportion, to control the flow of the various components, which make them sufficiently blended to achieve reproduction. In this paper, reproducing method is to find the corresponding liquid flavor, and then based on chemical flavor recipes, using flowmeters to control the chemical composition of the liquid flavor ratio. In the proportional control, the liquid chemical composition is very likely to be volatile, so that the proportional control is multiphase flow control. Measurement of the flow control will directly affect the odor reproducible results. Using electronic nose to obtain reproducible odor data, and then use pattern recognition algorithm to determine reproducible results. The experimental results can be achieved on the process of odor components multiphase flow proportional control parameter adjustment.

The smell of fear: innate threat of 2,5-dihydro-2,4,5-trimethylthiazoline, a single molecule component of a predator odor

PubMed Central

Rosen, Jeffrey B.; Asok, Arun; Chakraborty, Trisha

2015-01-01

In the last several years, the importance of understanding what innate threat and fear is, in addition to learning of threat and fear, has become evident. Odors from predators are ecologically relevant stimuli used by prey animals as warnings for the presence of danger. Of importance, these odors are not necessarily noxious or painful, but they have innate threat-like properties. This review summarizes the progress made on the behavioral and neuroanatomical fundamentals of innate fear of the predator odor, 2,5-dihydro-2,4,5-trimethylthiazoline (TMT), a component of fox feces. TMT is one of several single molecule components of predator odors that have been isolated in the last several years. Isolation of these single molecules has allowed for rapid advances in delineating the behavioral constraints and selective neuroanatomical pathways of predator odor induced fear. In naïve mice and rats, TMT induces a number of fear and defensive behaviors, including robust freezing, indicating it is an innate threat stimulus. However, there are a number of behavioral constraints that we do not yet understand. Similarly, while some of the early olfactory sensory pathways for TMT-induced fear are being delineated, the pathways from olfactory systems to emotional and motor output regions are less well understood. This review will focus on what we know and what we still need to learn about the behavior and neuroanatomy of TMT-induced fear. PMID:26379483

Effect of anatomy on human nasal air flow and odorant transport patterns: implications for olfaction.

PubMed

Zhao, Kai; Scherer, Peter W; Hajiloo, Shoreh A; Dalton, Pamela

2004-06-01

Recent studies that have compared CT or MRI images of an individual's nasal anatomy and measures of their olfactory sensitivity have found a correlation between specific anatomical areas and performance on olfactory assessments. Using computational fluid dynamics (CFD) techniques, we have developed a method to quickly (

Task-Dependent Behavioral Dynamics Make the Case for Temporal Integration in Multiple Strategies during Odor Processing

PubMed Central

Brown, Austin; Mehta, Nisarg; Vujovic, Mark; Amina, Tasneem; Fixsen, Bethany

2017-01-01

Differing results in olfactory-based decision-making research regarding the amount of time that rats and mice use to identify odors have led to some disagreements about odor-processing mechanics, including whether or not rodents use temporal integration (i.e., sniffing longer to identify odors better). Reported differences in behavioral strategies may be due to the different types of tasks used in different laboratories. Some researchers have reported that animals performing two-alternative choice (TAC) tasks need only 1–2 sniffs and do not increase performance with longer sampling. Others have reported that animals performing go/no-go (GNG) tasks increase sampling times and performance for difficult discriminations, arguing for temporal integration. We present results from four experiments comparing GNG and TAC tasks over several behavioral variables (e.g., performance, sampling duration). When rats know only one task, they perform better in GNG than in TAC. However, performance was not statistically different when rats learned and were tested in both tasks. Rats sample odors longer in GNG than in TAC, even when they know both tasks and perform them in the same or different sessions. Longer sampling is associated with better performance for both tasks in difficult discriminations, which supports the case for temporal integration over ≥2–6 sniffs in both tasks. These results illustrate that generalizations from a single task about behavioral or cognitive abilities (e.g., processing, perception) do not capture the full range of complexity and can significantly impact inferences about general abilities in sensory perception. SIGNIFICANCE STATEMENT Behavioral tasks and training and testing history affect measured outcomes in cognitive tests. Rats sample odors longer in a go/no-go (GNG) than in a two-alternative choice (TAC) task, performing better in GNG unless they know both tasks. Odor-sampling time is extended in both tasks when the odors to be discriminated are very similar. Rats may extend sampling time to integrate odor information up to ∼0.5 s (2–6 sniffs). Such factors as task, task parameters, and training history affect decision times and performance, making it important to use multiple tasks when making inferences about sensory or cognitive processing. PMID:28336570

Learning Modifies Odor Mixture Processing to Improve Detection of Relevant Components

PubMed Central

Chen, Jen-Yung; Marachlian, Emiliano; Assisi, Collins; Huerta, Ramon; Smith, Brian H.

2015-01-01

Honey bees have a rich repertoire of olfactory learning behaviors, and they therefore are an excellent model to study plasticity in olfactory circuits. Recent behavioral, physiological, and molecular evidence suggested that the antennal lobe, the first relay of the olfactory system in insects and analog to the olfactory bulb in vertebrates, is involved in associative and nonassociative olfactory learning. Here we use calcium imaging to reveal how responses across antennal lobe projection neurons change after association of an input odor with appetitive reinforcement. After appetitive conditioning to 1-hexanol, the representation of an odor mixture containing 1-hexanol becomes more similar to this odor and less similar to the background odor acetophenone. We then apply computational modeling to investigate how changes in synaptic connectivity can account for the observed plasticity. Our study suggests that experience-dependent modulation of inhibitory interactions in the antennal lobe aids perception of salient odor components mixed with behaviorally irrelevant background odors. PMID:25568113

Processes to Preserve Spice and Herb Quality and Sensory Integrity During Pathogen Inactivation.

PubMed

Duncan, Susan E; Moberg, Kayla; Amin, Kemia N; Wright, Melissa; Newkirk, Jordan J; Ponder, Monica A; Acuff, Gary R; Dickson, James S

2017-05-01

Selected processing methods, demonstrated to be effective at reducing Salmonella, were assessed to determine if spice and herb quality was affected. Black peppercorn, cumin seed, oregano, and onion powder were irradiated to a target dose of 8 kGy. Two additional processes were examined for whole black peppercorns and cumin seeds: ethylene oxide (EtO) fumigation and vacuum assisted-steam (82.22 °C, 7.5 psia). Treated and untreated spices/herbs were compared (visual, odor) using sensory similarity testing protocols (α = 0.20; β = 0.05; proportion of discriminators: 20%) to determine if processing altered sensory quality. Analytical assessment of quality (color, water activity, and volatile chemistry) was completed. Irradiation did not alter visual or odor sensory quality of black peppercorn, cumin seed, or oregano but created differences in onion powder, which was lighter (higher L * ) and more red (higher a * ) in color, and resulted in nearly complete loss of measured volatile compounds. EtO processing did not create detectable odor or appearance differences in black peppercorn; however visual and odor sensory quality differences, supported by changes in color (higher b * ; lower L * ) and increased concentrations of most volatiles, were detected for cumin seeds. Steam processing of black peppercorn resulted in perceptible odor differences, supported by increased concentration of monoterpene volatiles and loss of all sesquiterpenes; only visual differences were noted for cumin seed. An important step in process validation is the verification that no effect is detectable from a sensory perspective. © 2017 The Authors. Journal of Food Science published by Wiley Periodicals, Inc. on behalf of Institute of Food Technologists.

Differential Odor Sensitivity in PTSD: Implications for Treatment and Future Research

PubMed Central

Cortese, Bernadette M.; Leslie, Kimberly; Uhde, Thomas W.

2015-01-01

Background Given that odors enhance the retrieval of autobiographical memories, induce physiological arousal, and trigger trauma-related flashbacks, it is reasonable to hypothesize that odors play a significant role in the pathophysiology of posttraumatic stress disorder (PTSD). For these reasons, this preliminary study sought to examine self-reported, odor-elicited distress in PTSD. Methods Combat veterans with (N=30) and without (N=22) PTSD and healthy controls (HC: N=21), completed an olfactory questionnaire that provided information on the hedonic valence of odors as well as their ability to elicit distress or relaxation. Results Two main findings were revealed: Compared to HC, CV+PTSD, but not CV-PTSD, reported a higher prevalence of distress to a limited number of select odors that included fuel (p=.004), blood (p=.02), gunpowder (p=.03), and burning hair (p=.02). In contrast to this increased sensitivity, a blunting effect was reported by both groups of veterans compared to HC that revealed lower rates of distress and relaxation in response to negative hedonic odors (p=.03) and positive hedonic odors (p<.001), respectively. Limitations The study is limited by its use of retrospective survey methods, whereas future investigations would benefit from laboratory measures taken prior, during, and after deployment. Conclusion The present findings suggest a complex role of olfaction in the biological functions of threat detection. Several theoretical models are discussed. One possible explanation for increased sensitivity to select odors with decreased sensitivity to other odors is the co-occurrence of attentional bias toward threat odors with selective ignoring of distractor odors. Working together, these processes may optimize survival. PMID:25845746

Preliminary analysis of odor legal solutions and study on their implementation possibilities in Poland

NASA Astrophysics Data System (ADS)

Sówka, Izabela; Karski, Leszek

2018-01-01

The problem of odor nuisance requires undertaking legal means that aim towards implementation of regulations in order to improve the odor-related quality of air in selected areas in Poland. So far the works carried out in the country were concluded by drawing up `The guidelines for the bill on counteracting the odor nuisance'. However, as a result of completed social consultations in Poland, the Ministry of Environment, in 2015, resigned from implementing of so called anti-odor act. Currently, the legislature is taking steps which aim at undertaking specific actions in order to introduce solutions, which would directly regulate the issues of odors and the odor nuisance, to the national system. In the countries of the European Union, the issues related to odors are solved in diversified ways and the system still lacks of a uniform proposition, among others related to odor standards. In connection with the above, actions that are taken on a national level should fundamentally aim at developing national odor standards which would take into account the type / the kind of economic activity being a source of odor emission (e.g. clearly separated for existing objects and planned investments), at establishing a procedure and also legal and operational requirements related to determination and the types of zones with defined values of acceptable concentration and determination of reference methodology in monitoring, and modeling the dispersion of odors e.g. including strictly defined frequency of necessary tests. In addition, the process should be accompanied by a creation of financial mechanisms and streams in range of investments related to the development of technology and methods used to limit emission of odors.

Potential for reduction of odorous compounds in swine manure through diet modification.

PubMed

Sutton, A L; Kephart, K B; Verstegen, M W; Canh, T T; Hobbs, P J

1999-02-01

Recent public concern about air pollution from pork production units has prompted more research to develop methods to reduce and control odors. Masking agents, enzymes and bacterial preparations, feed additives, chemicals, oxidation processes, air scrubbers, biofilters, and new ventilation systems have been studied. Research relating the effects of the swine diet on manure odors has been scarce. Introducing feed additives to bind ammonia, change digesta pH, affect specific enzyme activity, and mask odors has been either costly or not consistently successful. Recent research emphasis has focused on manipulating the diet 1) to increase the nutrient utilization of the diet to reduce excretion products, 2) to enhance microbial metabolism in the lower digestive tract to reduce excretion of odor-causing compounds, and 3) to change the physical characteristics of urine and feces to reduce odor emissions. Primary odor-causing compounds evolve from excess degradable proteins and lack of specific fermentable carbohydrates during microbial fermentation. Reductions in ammonia emissions by 28 to 79% through diet modifications have been reported. Limited research on reduction of other odorous volatile organic compounds through diet modifications is promising. Use of synthetic amino acids with reduced intact protein levels in diets significantly reduces nitrogen excretions and odor production. Addition of nonstarch polysaccharides and specific oligosaccharides further alters the pathway of nitrogen excretion and reduces odor emission. Continued nutritional and microbial research to incorporate protein degradation products, especially sulfur-containing organics, with fermentable carbohydrates in the lower gastrointestinal tract of pigs will further control odors from manure.

Activation of Neural Pathways Associated with Sexual Arousal in Non-Human Primates

PubMed Central

Ferris, Craig F.; Snowdon, Charles T.; King, Jean A.; Sullivan, John M.; Ziegler, Toni E.; Olson, David P.; Schultz-Darken, Nancy J.; Tannenbaum, Pamela L.; Ludwig, Reinhold; Wu, Ziji; Einspanier, Almuth; Vaughan, J. Thomas; Duong, Timothy Q.

2006-01-01

Purpose To evaluate brain activity associated with sexual arousal, fully conscious male marmoset monkeys were imaged during presentation of odors that naturally elicit high levels of sexual activity and sexual motivation. Material and Methods Male monkeys were lightly anesthetized, secured in a head and body restrainer with a built-in birdcage resonator and positioned in a 9.4-Tesla spectrometer. When fully conscious, monkeys were presented with the odors of a novel receptive female or an ovariectomized monkey. Both odors were presented during an imaging trial and the presentation of odors was counterbalanced. Significant changes in both positive and negative BOLD signal were mapped and averaged. Results Periovulatory odors significantly increased positive BOLD signal in several cortical areas: the striatum, hippocampus, septum, periaqueductal gray, and cerebellum, in comparison with odors from ovariectomized monkeys. Conversely, negative BOLD signal was significantly increased in the temporal cortex, cingulate cortex, putamen, hippocampus, substantia nigra, medial preoptic area, and cerebellum with presentation of odors from ovariectomized marmosets as compared to periovulatory odors. A common neural circuit comprising the temporal and cingulate cortices, putamen, hippocampus, medial preoptic area, and cerebellum shared both the positive BOLD response to periovulatory odors and the negative BOLD response to odors of ovariectomized females. Conclusion These data suggest the odor-driven enhancement and suppression of sexual arousal affect neuronal activity in many of the same general brain areas. These areas included not only those associated with sexual activity, but also areas involved in emotional processing and reward. PMID:14745749

Guidelines for Design and Sampling for Cyanobacterial Toxin and Taste-and-Odor Studies in Lakes and Reservoirs

USGS Publications Warehouse

Graham, Jennifer L.; Loftin, Keith A.; Ziegler, Andrew C.; Meyer, Michael T.

2008-01-01

Cyanobacteria and associated toxins and taste-and-odor compounds are of increasing environmental concern. However, consistent guidelines for the development of studies assessing cyanobacterial toxins and taste-and-odor compounds presently are not available. This report provides guidance for the development of scientific studies of cyanobacteria and associated by-products in lakes and reservoirs. Topics include: background information on cyanobacteria, toxins, and taste-and-odor compounds; spatial and temporal considerations that are unique to the cyanobacteria in lakes and reservoirs; common study types, objectives, and approaches for studies of cyanobacteria and associated toxins and taste-and-odor compounds; general guidelines for collecting samples; and information on sample handling, preparation, processing, and shipping.

Female perception of male body odor.

PubMed

Sergeant, Mark J T

2010-01-01

Olfaction is one of the most crucial forms of communication among nonhuman animals. Historically, olfaction has been perceived as being of limited importance for humans, but recent research has documented that not only do humans have sensitive olfactory abilities, but also odors have the potential to influence our physiology and behavior. This chapter reviews research on olfactory communication among humans, focusing on the effects of male bodily odors on female physiology and behavior. The process of body odor production and the detection of olfactory signals are reviewed, focusing on potential sex differences in these abilities. The effects of male body odors on female physiological and behavioral effects of body odors are considered. Finally, with specific regard to female mate choice, evidence regarding the influence of the major histocompatibility complex and fluctuating asymmetry on male olfactory cues is reviewed. Copyright © 2010 Elsevier Inc. All rights reserved.

Excitatory Local Interneurons Enhance Tuning of Sensory Information

PubMed Central

Assisi, Collins; Stopfer, Mark; Bazhenov, Maxim

2012-01-01

Neurons in the insect antennal lobe represent odors as spatiotemporal patterns of activity that unfold over multiple time scales. As these patterns unspool they decrease the overlap between odor representations and thereby increase the ability of the olfactory system to discriminate odors. Using a realistic model of the insect antennal lobe we examined two competing components of this process –lateral excitation from local excitatory interneurons, and slow inhibition from local inhibitory interneurons. We found that lateral excitation amplified differences between representations of similar odors by recruiting projection neurons that did not receive direct input from olfactory receptors. However, this increased sensitivity also amplified noisy variations in input and compromised the ability of the system to respond reliably to multiple presentations of the same odor. Slow inhibition curtailed the spread of projection neuron activity and increased response reliability. These competing influences must be finely balanced in order to decorrelate odor representations. PMID:22807661

Alliesthesia is greater for odors of fatty foods than of non-fat foods.

PubMed

Plailly, Jane; Luangraj, Ninhda; Nicklaus, Sophie; Issanchou, Sylvie; Royet, Jean-Pierre; Sulmont-Rossé, Claire

2011-12-01

Alliesthesia is the modulation of the rewarding value of a stimulus according to the internal state (hungry or satiated). This study aimed to evaluate this phenomenon as a function of the nature of the stimulus (odors evoking edible and non-edible items, and the food odors evoking fatty and non-fat foods) and to compare the effectiveness of two reward evaluations (measures of pleasantness and appetence) to reveal alliesthesia. The results showed that both fatty and non-fat food odors were judged as less pleasant and less appetent when the subjects were satiated than when they were hungry, whereas no such difference was observed for non-food odors. There was a greater decrease in appetence than there was in pleasantness. Moreover, the decrease in appetence was greater for fatty than for non-fat food odors, whereas the decrease in pleasantness was similar for both fatty and non-fat food odors. Our study allows for the definition of a more comprehensive pattern of alliesthesia based on odor category. It demonstrates that alliesthesia is specific to food odors and that it is more pronounced when odors are associated with fatty rather than non-fat foods. It also reveals that an appetence measure is more sensitive than a pleasantness measure for describing an acute reward modulation process. Copyright © 2011 Elsevier Ltd. All rights reserved.

The impact of expertise in olfaction

PubMed Central

Royet, Jean-Pierre; Plailly, Jane; Saive, Anne-Lise; Veyrac, Alexandra; Delon-Martin, Chantal

2013-01-01

Olfactory expertise remains poorly understood, most likely because experts in odor, such as perfumers, sommeliers, and oenologists, are much rarer than experts in other modalities, such as musicians or sportsmen. In this review, we address the specificities of odor expertise in both odor experts and in a priori untrained individuals who have undergone specific olfactory training in the frame of an experiment, such as repeated exposure to odors or associative learning. Until the 21st century, only the behavioral effects of olfactory training of untrained control individuals had been reported, revealing an improvement of olfactory performance in terms of sensitivity, discrimination, memory, and identification. Behavioral studies of odor experts have been scarce, with inconsistent or inconclusive results. Recently, the development of cerebral imaging techniques has enabled the identification of brain areas and neural networks involved in odor processing, revealing functional and structural modifications as a function of experience. The behavioral approach to odor expertise has also evolved. Researchers have particularly focused on odor mental imagery, which is characteristic of odor experts, because this ability is absent in the average person but is part of a perfumer’s professional practice. This review summarizes behavioral, functional, and structural findings on odor expertise. These data are compared with those obtained using animals subjected to prolonged olfactory exposure or to olfactory-enriched environments and are discussed in the context of functional and structural plasticity. PMID:24379793

Neurobehavioral assessment of maternal odor in developing rat pups: implications for social buffering

PubMed Central

Al Aïn, Syrina; Perry, Rosemarie E.; Nuñez, Bestina; Kayser, Kassandra; Hochman, Chase; Brehman, Elizabeth; LaComb, Miranda; Wilson, Donald A.; Sullivan, Regina M.

2016-01-01

Social support can attenuate the behavioral and stress hormone response to threat, a phenomenon called social buffering. The mother’s social buffering of the infant is one of the more robust examples; yet we understand little about the neurobiology. Using a rodent model, we explore the neurobiology of social buffering by assessing neural processing of the maternal odor, a major cue controlling social buffering in rat pups. We used pups before (postnatal day (PN) 7) and after (PN14, PN23) the functional emergence of social buffering. Pups were injected with 14C 2-deoxyglucose (2-DG) and presented with the maternal odor, a control preferred odor incapable of social buffering (acetophenone), or no odor. Brains were removed, processed for autoradiography and brain areas identified as important in adult social buffering were assessed, including the amygdala basolateral complex (Basolateral Amygdala [BLA]), medial prefrontal cortex (mPFC), and anterior cingulate cortex (ACC). Results suggest dramatic changes in the processing of maternal odor. PN7 pups show mPFC and ACC activation, although PN14 pups showed no activation of the mPFC, ACC, or BLA. All brain areas assessed were recruited by PN23. Additional analysis suggests substantial changes in functional connectivity across development. Together, these results imply complex nonlinear transitions in the neurobiology of social buffering in early life that may provide insight into the changing role of the mother in supporting social buffering. PMID:26934130

Odors as effective retrieval cues for stressful episodes.

PubMed

Wiemers, Uta S; Sauvage, Magdalena M; Wolf, Oliver T

2014-07-01

Olfactory information seems to play a special role in memory due to the fast and direct processing of olfactory information in limbic areas like the amygdala and the hippocampus. This has led to the assumption that odors can serve as effective retrieval cues for autobiographic memories, especially emotional memories. The current study sought to investigate whether an olfactory cue can serve as an effective retrieval cue for memories of a stressful episode. A total of 95 participants were exposed to a psychosocial stressor or a well matching but not stressful control condition. During both conditions were visual objects present, either bound to the situation (central objects) or not (peripheral objects). Additionally, an ambient odor was present during both conditions. The next day, participants engaged in an unexpected object recognition task either under the influence of the same odor as was present during encoding (congruent odor) or another odor (non-congruent odor). Results show that stressed participants show a better memory for all objects and especially for central visual objects if recognition took place under influence of the congruent odor. An olfactory cue thus indeed seems to be an effective retrieval cue for stressful memories. Copyright © 2013 Elsevier Inc. All rights reserved.

DoOR 2.0 - Comprehensive Mapping of Drosophila melanogaster Odorant Responses

NASA Astrophysics Data System (ADS)

Münch, Daniel; Galizia, C. Giovanni

2016-02-01

Odors elicit complex patterns of activated olfactory sensory neurons. Knowing the complete olfactome, i.e. the responses in all sensory neurons for all relevant odorants, is desirable to understand olfactory coding. The DoOR project combines all available Drosophila odorant response data into a single consensus response matrix. Since its first release many studies were published: receptors were deorphanized and several response profiles were expanded. In this study, we add unpublished data to the odor-response profiles for four odorant receptors (Or10a, Or42b, Or47b, Or56a). We deorphanize Or69a, showing a broad response spectrum with the best ligands including 3-hydroxyhexanoate, alpha-terpineol, 3-octanol and linalool. We include all of these datasets into DoOR, provide a comprehensive update of both code and data, and new tools for data analyses and visualizations. The DoOR project has a web interface for quick queries (http://neuro.uni.kn/DoOR), and a downloadable, open source toolbox written in R, including all processed and original datasets. DoOR now gives reliable odorant-responses for nearly all Drosophila olfactory responding units, listing 693 odorants, for a total of 7381 data points.

DNA methylation mediates neural processing after odor learning in the honeybee

PubMed Central

Biergans, Stephanie D.; Claudianos, Charles; Reinhard, Judith; Galizia, C. Giovanni

2017-01-01

DNA methyltransferases (Dnmts) - epigenetic writers catalyzing the transfer of methyl-groups to cytosine (DNA methylation) – regulate different aspects of memory formation in many animal species. In honeybees, Dnmt activity is required to adjust the specificity of olfactory reward memories and bees’ relearning capability. The physiological relevance of Dnmt-mediated DNA methylation in neural networks, however, remains unknown. Here, we investigated how Dnmt activity impacts neuroplasticity in the bees’ primary olfactory center, the antennal lobe (AL) an equivalent of the vertebrate olfactory bulb. The AL is crucial for odor discrimination, an indispensable process in forming specific odor memories. Using pharmacological inhibition, we demonstrate that Dnmt activity influences neural network properties during memory formation in vivo. We show that Dnmt activity promotes fast odor pattern separation in trained bees. Furthermore, Dnmt activity during memory formation increases both the number of responding glomeruli and the response magnitude to a novel odor. These data suggest that Dnmt activity is necessary for a form of homoeostatic network control which might involve inhibitory interneurons in the AL network. PMID:28240742

Quantification and sensory studies of character impact odorants of different soybean lecithins.

PubMed

Stephan, A; Steinhart, H

1999-10-01

Fifty-four potent odorants in standardized, hydrolyzed, and deoiled and hydrolyzed soybean lecithins were quantified by high-resolution gas chromatography/mass spectrometry (HRGC/MS). The characterization of their aroma impact was performed by calculation of nasal (n) and retronasal (r) odor activity values (OAVs). For this, the nasal and retronasal recognition thresholds of 18 odor-active compounds were determined in vegetable oil. The following compounds showed the highest nOAVs: 2,3-diethyl-5-methylpyrazine, methylpropanal, acetic acid, pentanoic acid, 2-ethyl-3,5-dimethylpyrazine, pentylpyridine, (Z)-1,5-octadien-3-one, 2-methylbutanal, and beta-damascenone. In addition to the compounds above, 1-octen-3-one, 1-nonen-3-one, and 3-methyl-2,4-nonandione showed potent rOAVs. The results of quantification and OAV calculation were confirmed by a model mixture of 25 impact odorants, which yielded a highly similar sensory profile to that of the original soybean lecithin. The sensory importance of pyrazines and free acids increased through enzymatic hydrolysis and decreased by the process of deoiling. The impact of unsaturated ketones on the lecithin aroma was not changed by either process.

Advances in artificial olfaction: sensors and applications.

PubMed

Gutiérrez, J; Horrillo, M C

2014-06-01

The artificial olfaction, based on electronic systems (electronic noses), includes three basic functions that operate on an odorant: a sample handler, an array of gas sensors, and a signal-processing method. The response of these artificial systems can be the identity of the odorant, an estimate concentration of the odorant, or characteristic properties of the odour as might be perceived by a human. These electronic noses are bio inspired instruments that mimic the sense of smell. The complexity of most odorants makes characterisation difficult with conventional analysis techniques, such as gas chromatography. Sensory analysis by a panel of experts is a costly process since it requires trained people who can work for only relatively short periods of time. The electronic noses are easy to build, provide short analysis times, in real time and on-line, and show high sensitivity and selectivity to the tested odorants. These systems are non-destructive techniques used to characterise odorants in diverse applications linked with the quality of life such as: control of foods, environmental quality, citizen security or clinical diagnostics. However, there is much research still to be done especially with regard to new materials and sensors technology, data processing, interpretation and validation of results. This work examines the main features of modern electronic noses and their most important applications in the environmental, and security fields. The above mentioned main components of an electronic nose (sample handling system, more advanced materials and methods for sensing, and data processing system) are described. Finally, some interesting remarks concerning the strengths and weaknesses of electronic noses in the different applications are also mentioned. Copyright © 2014 Elsevier B.V. All rights reserved.

Reaction Mechanisms of Metals with Hydrogen Sulfide and Thiols in Model Wine. Part 1: Copper-Catalyzed Oxidation.

PubMed

Kreitman, Gal Y; Danilewicz, John C; Jeffery, David W; Elias, Ryan J

2016-05-25

Sulfidic off-odors as a result of hydrogen sulfide (H2S) and low-molecular-weight thiols are commonly encountered in wine production. These odors are usually removed by the process of Cu(II) fining, a process that remains poorly understood. The present study aims to elucidate the underlying mechanisms by which Cu(II) interacts with H2S and thiol compounds (RSH) under wine-like conditions. Copper complex formation was monitored along with H2S, thiol, oxygen, and acetaldehyde concentrations after the addition of Cu(II) (50 or 100 μM) to air-saturated model wine solutions containing H2S, cysteine, 6-sulfanylhexan-1-ol, or 3-sulfanylhexan-1-ol (300 μM each). The presence of H2S and thiols in excess to Cu(II) led to the rapid formation of ∼1.4:1 H2S/Cu and ∼2:1 thiol/Cu complexes, resulting in the oxidation of H2S and thiols and reduction of Cu(II) to Cu(I), which reacted with oxygen. H2S was observed to initially oxidize rather than form insoluble copper sulfide. The proposed reaction mechanisms provide insight into the extent to which H2S can be selectively removed in the presence of thiols in wine.

Transcriptomes of Mouse Olfactory Epithelium Reveal Sexual Differences in Odorant Detection

PubMed Central

Shiao, Meng-Shin; Chang, Andrew Ying-Fei; Liao, Ben-Yang; Ching, Yung-Hao; Lu, Mei-Yeh Jade; Chen, Stella Maris; Li, Wen-Hsiung

2012-01-01

To sense numerous odorants and chemicals, animals have evolved a large number of olfactory receptor genes (Olfrs) in their genome. In particular, the house mouse has ∼1,100 genes in the Olfr gene family. This makes the mouse a good model organism to study Olfr genes and olfaction-related genes. To date, whether male and female mice possess the same ability in detecting environmental odorants is still unknown. Using the next generation sequencing technology (paired-end mRNA-seq), we detected 1,088 expressed Olfr genes in both male and female olfactory epithelium. We found that not only Olfr genes but also odorant-binding protein (Obp) genes have evolved rapidly in the mouse lineage. Interestingly, Olfr genes tend to express at a higher level in males than in females, whereas the Obp genes clustered on the X chromosome show the opposite trend. These observations may imply a more efficient odorant-transporting system in females, whereas a more active Olfr gene expressing system in males. In addition, we detected the expression of two genes encoding major urinary proteins, which have been proposed to bind and transport pheromones or act as pheromones in mouse urine. This observation suggests a role of main olfactory system (MOS) in pheromone detection, contrary to the view that only accessory olfactory system (AOS) is involved in pheromone detection. This study suggests the sexual differences in detecting environmental odorants in MOS and demonstrates that mRNA-seq provides a powerful tool for detecting genes with low expression levels and with high sequence similarities. PMID:22511034

Modelling Odor Decoding in the Antennal Lobe by Combining Sequential Firing Rate Models with Bayesian Inference

PubMed Central

Cuevas Rivera, Dario; Bitzer, Sebastian; Kiebel, Stefan J.

2015-01-01

The olfactory information that is received by the insect brain is encoded in the form of spatiotemporal patterns in the projection neurons of the antennal lobe. These dense and overlapping patterns are transformed into a sparse code in Kenyon cells in the mushroom body. Although it is clear that this sparse code is the basis for rapid categorization of odors, it is yet unclear how the sparse code in Kenyon cells is computed and what information it represents. Here we show that this computation can be modeled by sequential firing rate patterns using Lotka-Volterra equations and Bayesian online inference. This new model can be understood as an ‘intelligent coincidence detector’, which robustly and dynamically encodes the presence of specific odor features. We found that the model is able to qualitatively reproduce experimentally observed activity in both the projection neurons and the Kenyon cells. In particular, the model explains mechanistically how sparse activity in the Kenyon cells arises from the dense code in the projection neurons. The odor classification performance of the model proved to be robust against noise and time jitter in the observed input sequences. As in recent experimental results, we found that recognition of an odor happened very early during stimulus presentation in the model. Critically, by using the model, we found surprising but simple computational explanations for several experimental phenomena. PMID:26451888

Brain processing of biologically relevant odors in the awake rat, as revealed by manganese-enhanced MRI.

PubMed

Lehallier, Benoist; Rampin, Olivier; Saint-Albin, Audrey; Jérôme, Nathalie; Ouali, Christian; Maurin, Yves; Bonny, Jean-Marie

2012-01-01

So far, an overall view of olfactory structures activated by natural biologically relevant odors in the awake rat is not available. Manganese-enhanced MRI (MEMRI) is appropriate for this purpose. While MEMRI has been used for anatomical labeling of olfactory pathways, functional imaging analyses have not yet been performed beyond the olfactory bulb. Here, we have used MEMRI for functional imaging of rat central olfactory structures and for comparing activation maps obtained with odors conveying different biological messages. Odors of male fox feces and of chocolate flavored cereals were used to stimulate conscious rats previously treated by intranasal instillation of manganese (Mn). MEMRI activation maps showed Mn enhancement all along the primary olfactory cortex. Mn enhancement elicited by male fox feces odor and to a lesser extent that elicited by chocolate odor, differed from that elicited by deodorized air. This result was partly confirmed by c-Fos immunohistochemistry in the piriform cortex. By providing an overall image of brain structures activated in awake rats by odorous stimulation, and by showing that Mn enhancement is differently sensitive to different stimulating odors, the present results demonstrate the interest of MEMRI for functional studies of olfaction in the primary olfactory cortex of laboratory small animals, under conditions close to natural perception. Finally, the factors that may cause the variability of the MEMRI signal in response to different odor are discussed.

Receptor modeling of a natural gas processing odor source in a rural setting

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dattner, S.; Pendleton, D.; Ross, O.

1985-01-01

The use of continuous pollutant monitoring instruments and meteorological instruments has been shown to be useful in identifying the probable sources of elevated levels of gaseous sulfur compounds even when those levels were, significantly below health effect levels or odor threshold, or both. When the elevated concentrations were compared to complaint diaries, significant agreement could be seen. This agreement helped to establish the probable source of the odors. Once the odor sources could be accurately identified, remedial action could be taken to control them. The biggest problem that the TACB encountered was convincing the complainants to keep an odor complaintmore » diary. Two combined actions are being considered to aleviate this difficulty. First, produce a standardized odor complaint diary. This document will have space for all the pertinent information needed. The standardized form may encourage the complainants to complete them, since the complainant won't have to guess what to report. The form should include space for the following information: Date, time, and duration of odor problem; Nature of odor; Associated meteorology; Times when the complainant was not home. Second, encourage the complainants to complete the diary. The complainant has to be convinced that the information reported in the diary is vital to establishing a link between odors and elevated pollutant concentrations. The agency may need to require formally that a diary be kept as a condition to conduct monitoring.« less

EMMC process for combined removal of organics, nitrogen and an odor producing substance.

PubMed

Yang, P Y; Su, R; Kim, S J

2003-12-01

In order to improve the process performance regarding the removal of organics, nitrogen, and an odor-causing compound (sulfide) contained in domestic wastewater, an entrapped-mixed-microbial cell (EMMC) with and without humic substances for both fixed and moving carrier reactors and conventional suspended growth culture (i.e. conventional activated sludge process) were investigated simultaneously. Both synthetic (simulated to the organics concentration of general domestic sewage) and actual domestic wastewater were investigated under operational conditions of 12 h of hydraulic retention time (HRT) with 1 h of aeration and 1 h of non-aeration, and 6 h of HRT with continuous aeration, at a room temperature of 25 +/- 2 degrees C. It was found that entrapping humic substances in the EMMC carriers had no impact on the removal of organics, nitrogen, and the odor-producing compound. Additionally, the performance of the EMMC moving carrier system for the removal of these pollutants is similar to that of the EMMC fixed carrier system. In general, the EMMC associated systems which provide high solids retention time achieve a better removal of chemical oxygen demand (COD), nitrogen, and the odor-producing substance than the suspended growth system for both HRTs of 6 h (continuous aeration) and 12 h (1 h of aeration and 1 h of non-aeration). Both the fixed and moving carrier EMMC processes, therefore, have the potential for improvement or replacement of the existing conventional activated sludge process with regard to improving the effluent qualities (such as COD, nitrogen and odor-producing compound) for reuse/disposal.

Rapid evolution of chemosensory receptor genes in a pair of sibling species of orchid bees (Apidae: Euglossini).

PubMed

Brand, Philipp; Ramírez, Santiago R; Leese, Florian; Quezada-Euan, J Javier G; Tollrian, Ralph; Eltz, Thomas

2015-08-28

Insects rely more on chemical signals (semiochemicals) than on any other sensory modality to find, identify, and choose mates. In most insects, pheromone production is typically regulated through biosynthetic pathways, whereas pheromone sensory detection is controlled by the olfactory system. Orchid bees are exceptional in that their semiochemicals are not produced metabolically, but instead male bees collect odoriferous compounds (perfumes) from the environment and store them in specialized hind-leg pockets to subsequently expose during courtship display. Thus, the olfactory sensory system of orchid bees simultaneously controls male perfume traits (sender components) and female preferences (receiver components). This functional linkage increases the opportunities for parallel evolution of male traits and female preferences, particularly in response to genetic changes of chemosensory detection (e.g. Odorant Receptor genes). To identify whether shifts in pheromone composition among related lineages of orchid bees are associated with divergence in chemosensory genes of the olfactory periphery, we searched for patterns of divergent selection across the antennal transcriptomes of two recently diverged sibling species Euglossa dilemma and E. viridissima. We identified 3185 orthologous genes including 94 chemosensory loci from five different gene families (Odorant Receptors, Ionotropic Receptors, Gustatory Receptors, Odorant Binding Proteins, and Chemosensory Proteins). Our results revealed that orthologs with signatures of divergent selection between E. dilemma and E. viridissima were significantly enriched for chemosensory genes. Notably, elevated signals of divergent selection were almost exclusively observed among chemosensory receptors (i.e. Odorant Receptors). Our results suggest that rapid changes in the chemosensory gene family occurred among closely related species of orchid bees. These findings are consistent with the hypothesis that strong divergent selection acting on chemosensory receptor genes plays an important role in the evolution and diversification of insect pheromone systems.

Directional coupling from the olfactory bulb to the hippocampus during a go/no-go odor discrimination task.

PubMed

Gourévitch, Boris; Kay, Leslie M; Martin, Claire

2010-05-01

The hippocampus and olfactory regions are anatomically close, and both play a major role in memory formation. However, the way they interact during odor processing is still unclear. In both areas, strong oscillations of the local field potential (LFP) can be recorded, and are modulated by behavior. In particular, in the olfactory system, the beta rhythm (15-35 Hz) is associated with cognitive processing of an olfactory stimulus. Using LFP recordings in the olfactory bulb and dorsal and ventral hippocampus during performance of an olfactory go/no-go task in rats, we previously showed that beta oscillations are also present in the hippocampus, coherent with those in the olfactory bulb, during odor sampling. In this study, we provide further insight into information transfer in the olfacto-hippocampal network by using directional coherence (DCOH estimate), a method based on the temporal relation between two or more signals in the frequency domain. In the theta band (6-12 Hz), coherence between the olfactory bulb (OB) and the hippocampus (HPC) is weak and can be both in the feedback and feedforward directions. However, at this frequency, modulation of the coupling between the dorsal and ventral hippocampus is seen during stimulus expectation versus odor processing. In the beta frequency band (15-35 Hz), analysis showed a strong unidirectional coupling from the OB to dorsal and ventral HPC, indicating that, during odor processing, beta oscillations in the hippocampus are driven by the olfactory bulb.

Adaptation to Variance of Stimuli in Drosophila Larva Navigation

NASA Astrophysics Data System (ADS)

Wolk, Jason; Gepner, Ruben; Gershow, Marc

In order to respond to stimuli that vary over orders of magnitude while also being capable of sensing very small changes, neural systems must be capable of rapidly adapting to the variance of stimuli. We study this adaptation in Drosophila larvae responding to varying visual signals and optogenetically induced fictitious odors using an infrared illuminated arena and custom computer vision software. Larval navigational decisions (when to turn) are modeled as the output a linear-nonlinear Poisson process. The development of the nonlinear turn rate in response to changes in variance is tracked using an adaptive point process filter determining the rate of adaptation to different stimulus profiles. Supported by NIH Grant 1DP2EB022359 and NSF Grant PHY-1455015.

Integral approaches to wastewater treatment plant upgrading for odor prevention: Activated Sludge and Oxidized Ammonium Recycling.

PubMed

Estrada, José M; Kraakman, N J R; Lebrero, R; Muñoz, R

2015-11-01

Traditional physical/chemical end-of-the-pipe technologies for odor abatement are relatively expensive and present high environmental impacts. On the other hand, biotechnologies have recently emerged as cost-effective and environmentally friendly alternatives but are still limited by their investment costs and land requirements. A more desirable approach to odor control is the prevention of odorant formation before being released to the atmosphere, but limited information is available beyond good design and operational practices of the wastewater treatment process. The present paper reviews two widely applicable and economic alternatives for odor control, Activated Sludge Recycling (ASR) and Oxidized Ammonium Recycling (OAR), by discussing their fundamentals, key operating parameters and experience from the available pilot and field studies. Both technologies present high application potential using readily available plant by-products with a minimum plant upgrading, and low investment and operating costs, contributing to the sustainability and economic efficiency of odor control at wastewater treatment facilities. Copyright © 2015 Elsevier Ltd. All rights reserved.

The Orexin Component of Fasting Triggers Memory Processes Underlying Conditioned Food Selection in the Rat

ERIC Educational Resources Information Center

Ferry, Barbara; Duchamp-Viret, Patricia

2014-01-01

To test the selectivity of the orexin A (OXA) system in olfactory sensitivity, the present study compared the effects of fasting and of central infusion of OXA on the memory processes underlying odor-malaise association during the conditioned odor aversion (COA) paradigm. Animals implanted with a cannula in the left ventricle received ICV infusion…

Isolation and Characterization of the Gene Associated with Geosmin Production in Cyanobacteria

PubMed Central

Giglio, Steven; Jiang, Jiaoyang; Saint, Christopher P; Cane, David; Monis, Paul T

2009-01-01

Geosmin is a secondary metabolite responsible for earthy tastes and odors in potable water supplies. Geosmin continues to be a challenge to water utility management regimes and remains one of the most common causes of consumer complaints, as the taste of “dirty” water may suggest a failed disinfection regime and that the water may be unsafe to drink. Although cyanobacteria have been reported to be largely responsible for these taste and odor events, the answer as to how or why geosmin is produced has eluded researchers. We describe here for the first time the mechanism by which geosmin is produced in a model cyanobacterium, Nostoc punctiforme PCC 73102 (ATCC 29133), which we demonstrate utilizes a single enzyme to catalyze the cyclization of farnesyl diphosphate to geosmin. Using this information, we have developed a PCR-based assay that allows the rapid detection of geosmin-producing cyanobacteria. This test may be utilized to confirm and track the emergence of taste and odor-producing cyanobacteria in any given water body and thus can be used as an early warning system by managers of water bodies that may suffer from adverse taste and odor episodes. PMID:19031897

Dissecting the Signaling Mechanisms Underlying Recognition and Preference of Food Odors

PubMed Central

Harris, Gareth; Shen, Yu; Ha, Heonick; Donato, Alessandra; Wallis, Samuel; Zhang, Xiaodong

2014-01-01

Food is critical for survival. Many animals, including the nematode Caenorhabditis elegans, use sensorimotor systems to detect and locate preferred food sources. However, the signaling mechanisms underlying food-choice behaviors are poorly understood. Here, we characterize the molecular signaling that regulates recognition and preference between different food odors in C. elegans. We show that the major olfactory sensory neurons, AWB and AWC, play essential roles in this behavior. A canonical Gα-protein, together with guanylate cyclases and cGMP-gated channels, is needed for the recognition of food odors. The food-odor-evoked signal is transmitted via glutamatergic neurotransmission from AWC and through AMPA and kainate-like glutamate receptor subunits. In contrast, peptidergic signaling is required to generate preference between different food odors while being dispensable for the recognition of the odors. We show that this regulation is achieved by the neuropeptide NLP-9 produced in AWB, which acts with its putative receptor NPR-18, and by the neuropeptide NLP-1 produced in AWC. In addition, another set of sensory neurons inhibits food-odor preference. These mechanistic logics, together with a previously mapped neural circuit underlying food-odor preference, provide a functional network linking sensory response, transduction, and downstream receptors to process complex olfactory information and generate the appropriate behavioral decision essential for survival. PMID:25009271

The orexin-1 receptor antagonist SB-334867 decreases anxiety-like behavior and c-Fos expression in the hypothalamus of rats exposed to cat odor.

PubMed

Vanderhaven, M W; Cornish, J L; Staples, L G

2015-02-01

Increasing evidence suggests that the orexin system is involved in modulating anxiety, and we have recently shown that cat odor-induced anxiety in rats is attenuated by the orexin receptor antagonist SB-334867. In the current experiment, c-Fos expression was used to map changes in neuronal activation following SB-334867 administration in the cat odor anxiety model. Male Wistar rats were exposed to cat odor with or without SB-334867 pre-treatment (10 mg/kg, i.p.). A naïve control group not exposed to cat odor was also used. Following cat odor exposure, brains were processed for c-Fos expression. Vehicle-treated rats showed an increase in anxiety-like behaviors (increased hiding and decreased approach toward the cat odor), and increased c-Fos expression in the posteroventral medial amygdala (MePV), paraventricular hypothalamus (PVN) and dorsal premammillary nucleus (PMd). In rats pretreated with SB-334867, approach scores increased and c-Fos expression decreased in the PVN and PMd. These results provide both behavioral and neuroanatomical evidence for the attenuation of cat odor-induced anxiety in rats via the orexin system. Crown Copyright © 2014. Published by Elsevier B.V. All rights reserved.

Blocking and the detection of odor components in blends.

PubMed

Hosler, J S; Smith, B H

2000-09-01

Recent studies of olfactory blocking have revealed that binary odorant mixtures are not always processed as though they give rise to mixture-unique configural properties. When animals are conditioned to one odorant (A) and then conditioned to a mixture of that odorant with a second (X), the ability to learn or express the association of X with reinforcement appears to be reduced relative to animals that were not preconditioned to A. A recent model of odor-based response patterns in the insect antennal lobe predicts that the strength of the blocking effect will be related to the perceptual similarity between the two odorants, i.e. greater similarity should increase the blocking effect. Here, we test that model in the honeybee Apis mellifera by first establishing a generalization matrix for three odorants and then testing for blocking between all possible combinations of them. We confirm earlier findings demonstrating the occurrence of the blocking effect in olfactory learning of compound stimuli. We show that the occurrence and the strength of the blocking effect depend on the odorants used in the experiment. In addition, we find very good agreement between our results and the model, and less agreement between our results and an alternative model recently proposed to explain the effect.

The role of algae and cyanobacteria in the production and release of odorants in water.

PubMed

Lee, Jechan; Rai, Prabhat Kumar; Jeon, Young Jae; Kim, Ki-Hyun; Kwon, Eilhann E

2017-08-01

This review covers literatures pertaining to algal and cyanobacterial odor problems that have been published over the last five decades. Proper evaluation of algal and cyanobacterial odors may help establish removal strategies for hazardous metabolites while enhancing the recyclability of water. A bloom of microalgae is a sign of an anthropogenic disturbance in aquatic systems and can lead to diverse changes in ecosystems along with increased production of odorants. In general, because algal and cyanobacterial odors vary in chemistry and intensity according to blooming pattern, it is necessary to learn more about the related factors and processes (e.g., changes due to differences in taxa). This necessitates systematic and transdisciplinary approaches that require the cooperation of chemists, biologists, engineers, and policy makers. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Effects of Pre-Exposure to DEET on the Downstream Blood-Feeding Behaviors of Aedes aegypti Mosquitoes

DTIC Science & Technology

2016-06-10

house the odorant receptor neurons (Amer 48 DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited. UNCLASSIFIED 3 and...Mehlhorn 2006, Hallem et al. 2006, Paluch et al. 2010). The insect olfactory process starts 49 when odorant molecules enter the pores located on the...sensilla. Each sensillum contains 50 olfactory receptor neurons that have odorant receptors on its surface. As the molecule enters the 51 pores, the

Composting municipal biosolids in polyethylene sleeves with forced aeration: Process control, air emissions, sanitary and agronomic aspects.

PubMed

Avidov, R; Saadi, I; Krassnovsky, A; Hanan, A; Medina, Sh; Raviv, M; Chen, Y; Laor, Y

2017-09-01

Composting in polyethylene sleeves with forced aeration may minimize odor emissions, vectors attraction and leachates associated with open windrows. A disadvantage of this technology is the lack of mixing during composting, potentially leading to non-uniform products. In two pilot experiments using biosolids and green waste (1:1; v:v), thermophilic conditions (>45°C) were maintained for two months, with successful control of oxygen levels and sufficient moisture. Emitted odors declined from 1.5-3.8×10 5 to 5.9×10 3 -2.3×10 4 odor units m -3 -air in the first 3weeks of the process, emphasizing the need of odor control primarily during this period. Therefore, composting might be managed in two phases: (i) a closed sleeve for 6-8weeks during which the odor is treated; (ii) an open pile (odor control is not necessary). Reduction of salmonella, E. coli and coliforms was effective initially, meeting the standards of "Class A" biosolids; however, total and fecal coliforms density increased after opening the second sleeve and exceeded the standard of 1000 most probable number (MPN) per g dry matter. Compost maturity was achieved in the open piles following the two sleeves and the final compost was non-phytotoxic and beneficial as a soil additive. Copyright © 2017 Elsevier Ltd. All rights reserved.

Investigation of the effects of temperature and sludge characteristics on odors and VOC emissions during the drying process of sewage sludge.

PubMed

Ding, Wenjie; Li, Lin; Liu, Junxin

2015-01-01

Sludge drying is a necessary step for sludge disposal. In this study, sludge was collected from two wastewater treatment plants, and dried at different temperatures in the laboratory. The emission of odor and total volatile organic compounds (TVOCs) during the sludge drying process were determined by an online odor monitoring system. The volatile organic compounds (VOCs) in off-gas were analyzed by gas chromatography-mass spectrometry. Results showed that sludge with 30% moisture content could be obtained in 51 minutes under drying temperature 100 °C but only within 27 minutes under 150 °C. Concentration of odor, TVOCs, sulfur-containing compounds (SCCs), and amines were changed with drying temperature and sludge sources. The maximum concentration of odor, TVOCs, SCCs, and amines were 503.13 ppm, 3.01 ppm, 8.15 ppm, and 11.27 ppm, respectively, at drying temperature 100 °C. These values reached 1,250.79, 8.10, 53.51, and 37.80 ppm when sludge dried at 150 °C. Odor concentration had a close relationship with emission of SCCs, amines, and TVOCs. The main VOCs released were benzene series and organic acid. Potential migration of substances in sludge was examined via analysis of off-gas and condensate, aiming to provide scientific data for effective sludge treatment and off-gas control.

Preservation of Essential Odor-Guided Behaviors and Odor-Based Reversal Learning after Targeting Adult Brain Serotonin Synthesis.

PubMed

Carlson, Kaitlin S; Whitney, Meredith S; Gadziola, Marie A; Deneris, Evan S; Wesson, Daniel W

2016-01-01

The neurotransmitter serotonin (5-HT) is considered a powerful modulator of sensory system organization and function in a wide range of animals. The olfactory system is innervated by midbrain 5-HT neurons into both its primary and secondary odor-processing stages. Facilitated by this circuitry, 5-HT and its receptors modulate olfactory system function, including odor information input to the olfactory bulb. It is unknown, however, whether the olfactory system requires 5-HT for even its most basic behavioral functions. To address this question, we established a conditional genetic approach to specifically target adult brain tryptophan hydroxylase 2 ( Tph2 ), encoding the rate-limiting enzyme in brain 5-HT synthesis, and nearly eliminate 5-HT from the mouse forebrain. Using this novel model, we investigated the behavior of 5-HT-depleted mice during performance in an olfactory go/no-go task. Surprisingly, the near elimination of 5-HT from the forebrain, including the olfactory bulbs, had no detectable effect on the ability of mice to perform the odor-based task. Tph2 -targeted mice not only were able to learn the task, but also had levels of odor acuity similar to those of control mice when performing coarse odor discrimination. Both groups of mice spent similar amounts of time sampling odors during decision-making. Furthermore, odor reversal learning was identical between 5-HT-depleted and control mice. These results suggest that 5-HT neurotransmission is not necessary for the most essential aspects of olfaction, including odor learning, discrimination, and certain forms of cognitive flexibility.

Olfactory Context-Dependent Memory and the Effects of Affective Congruency.

PubMed

Hackländer, Ryan P M; Bermeitinger, Christina

2017-10-31

Odors have been claimed to be particularly effective mnemonic cues, possibly because of the strong links between olfaction and emotion processing. Indeed, past research has shown that odors can bias processing towards affectively congruent material. In order to determine whether this processing bias translates to memory, we conducted 2 olfactory-enhanced-context memory experiments where we manipulated affective congruency between the olfactory context and to-be-remembered material. Given the presumed importance of valence to olfactory perception, we hypothesized that memory would be best for affectively congruent material in the olfactory enhanced context groups. Across the 2 experiments, groups which encoded and retrieved material in the presence of an odorant exhibited better memory performance than groups that did not have the added olfactory context during encoding and retrieval. While context-enhanced memory was exhibited in the presence of both pleasant and unpleasant odors, there was no indication that memory was dependent on affective congruency between the olfactory context and the to-be-remembered material. While the results provide further support for the notion that odors can act as powerful contextual mnemonic cues, they call into question the notion that affective congruency between context and focal material is important for later memory performance. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Associative Processes in Early Olfactory Preference Acquisition

PubMed Central

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

2007-01-01

Acquisition of behavioral conditioned responding and learned odor preferences during olfactory classical conditioning in rat pups requires forward or simultaneous pairings of the conditioned stimulus (CS) and the unconditioned stimulus (US). Other temporal relationships between the CS and US do not usually result in learning. The present study examined the influence of this CS-US relationship upon the neural olfactory bulb modifications that are acquired during early classical conditioning. Wistar rat pups were trained from Postnatal Days (PN) 1-18 with either forward (odor overlapping temporally with reinforcing stroking) or backward (stroking followed by odor) CS-US pairings. On PN 19, pups received either a behavioral odor preference test to the odor CS or an injection of 14C 2-DG and exposure to the odor CS, or olfactory bulb single unit responses were recorded in response to exposure to the odor CS. Only pups that received forward presentations of the CS and US exhibited both a preference for the CS and modified olfactory bulb neural responses to the CS. These results, then, suggest that the modified olfactory bulb neural responses acquired during classical conditioning are guided by the same temporal constraints as those which govern the acquisition of behavioral conditioned responses. PMID:17572798

Attentional modulation of desensitization to odor.

PubMed

Fallon, Nicholas; Giesbrecht, Timo; Stancak, Andrej

2018-05-22

Subjective and behavioral responsiveness to odor diminishes during prolonged exposure. The precise mechanisms underlying olfactory desensitization are not fully understood, but previous studies indicate that the phenomenon may be modulated by central-cognitive processes. The present study investigated the effect of attention on perceived intensity during exposure to a pleasant odor. A within-subjects design was utilized with 19 participants attending 2 sessions. During each session, participants continuously rated their perceived intensity of a 10-minute exposure to a pleasant fragrance administered using an olfactometer. An auditory oddball task was implemented to manipulate the focus of attention in each session. Participants were instructed to either direct their attention toward the sounds, but still to rate odor, or to focus entirely on rating the odor. Analysis revealed three 50-second time windows with significantly lower mean intensity ratings during the distraction condition. Curve fitting of the data disclosed a linear function of desensitization in the focused attention condition compared with an exponential decay function during distraction condition, indicating an increased rate of initial desensitization when attention is distracted away from the odor. In the focused-attention condition, perceived intensity demonstrated a regular pattern of odor sensitivity occurring at approximately 1-2 minutes intervals following initial desensitization. Spectral analysis of low-frequency oscillations confirmed the presence of augmented spectral power in this frequency range during focused relative to distracted conditions. The findings demonstrate for the first time modulation of odor desensitization specifically by attentional factors, exemplifying the relevance of top-down control for ongoing perception of odor.

An antennal carboxylesterase from Drosophila melanogaster, esterase 6, is a candidate odorant-degrading enzyme toward food odorants.

PubMed

Chertemps, Thomas; Younus, Faisal; Steiner, Claudia; Durand, Nicolas; Coppin, Chris W; Pandey, Gunjan; Oakeshott, John G; Maïbèche, Martine

2015-01-01

Reception of odorant molecules within insect olfactory organs involves several sequential steps, including their transport through the sensillar lymph, interaction with the respective sensory receptors, and subsequent inactivation. Odorant-degrading enzymes (ODEs) putatively play a role in signal dynamics by rapid degradation of odorants in the vicinity of the receptors, but this hypothesis is mainly supported by in vitro results. We have recently shown that an extracellular carboxylesterase, esterase-6 (EST-6), is involved in the physiological and behavioral dynamics of the response of Drosophila melanogaster to its volatile pheromone ester, cis-vaccenyl acetate. However, as the expression pattern of the Est-6 gene in the antennae is not restricted to the pheromone responding sensilla, we tested here if EST-6 could play a broader function in the antennae. We found that recombinant EST-6 is able to efficiently hydrolyse several volatile esters that would be emitted by its natural food in vitro. Electrophysiological comparisons of mutant Est-6 null flies and a control strain (on the same genetic background) showed that the dynamics of the antennal response to these compounds is influenced by EST-6, with the antennae of the null mutants showing prolonged activity in response to them. Antennal responses to the strongest odorant, pentyl acetate, were then studied in more detail, showing that the repolarization dynamics were modified even at low doses but without modification of the detection threshold. Behavioral choice experiments with pentyl acetate also showed differences between genotypes; attraction to this compound was observed at a lower dose among the null than control flies. As EST-6 is able to degrade various bioactive odorants emitted by food and plays a role in the response to these compounds, we hypothesize a role as an ODE for this enzyme toward food volatiles.

It's time to fear! Interval timing in odor fear conditioning in rats

PubMed Central

Shionoya, Kiseko; Hegoburu, Chloé; Brown, Bruce L.; Sullivan, Regina M.; Doyère, Valérie; Mouly, Anne-Marie

2013-01-01

Time perception is crucial to goal attainment in humans and other animals, and interval timing also guides fundamental animal behaviors. Accumulating evidence has made it clear that in associative learning, temporal relations between events are encoded, and a few studies suggest this temporal learning occurs very rapidly. Most of these studies, however, have used methodologies that do not permit investigating the emergence of this temporal learning. In the present study we monitored respiration, ultrasonic vocalization (USV) and freezing behavior in rats in order to perform fine-grain analysis of fear responses during odor fear conditioning. In this paradigm an initially neutral odor (the conditioned stimulus, CS) predicted the arrival of an aversive unconditioned stimulus (US, footshock) at a fixed 20-s time interval. We first investigated the development of a temporal pattern of responding related to CS-US interval duration. The data showed that during acquisition with odor-shock pairings, a temporal response pattern of respiration rate was observed. Changing the CS-US interval duration from 20-s to 30-s resulted in a shift of the temporal response pattern appropriate to the new duration thus demonstrating that the pattern reflected the learning of the CS-US interval. A temporal pattern was also observed during a retention test 24 h later for both respiration and freezing measures, suggesting that the animals had stored the interval duration in long-term memory. We then investigated the role of intra-amygdalar dopaminergic transmission in interval timing. For this purpose, the D1 dopaminergic receptors antagonist SCH23390 was infused in the basolateral amygdala before conditioning. This resulted in an alteration of timing behavior, as reflected in differential temporal patterns between groups observed in a 24 h retention test off drug. The present data suggest that D1 receptor dopaminergic transmission within the amygdala is involved in temporal processing. PMID:24098277

Sensory memory for odors is encoded in spontaneous correlated activity between olfactory glomeruli.

PubMed

Galán, Roberto F; Weidert, Marcel; Menzel, Randolf; Herz, Andreas V M; Galizia, C Giovanni

2006-01-01

Sensory memory is a short-lived persistence of a sensory stimulus in the nervous system, such as iconic memory in the visual system. However, little is known about the mechanisms underlying olfactory sensory memory. We have therefore analyzed the effect of odor stimuli on the first odor-processing network in the honeybee brain, the antennal lobe, which corresponds to the vertebrate olfactory bulb. We stained output neurons with a calcium-sensitive dye and measured across-glomerular patterns of spontaneous activity before and after a stimulus. Such a single-odor presentation changed the relative timing of spontaneous activity across glomeruli in accordance with Hebb's theory of learning. Moreover, during the first few minutes after odor presentation, correlations between the spontaneous activity fluctuations suffice to reconstruct the stimulus. As spontaneous activity is ubiquitous in the brain, modifiable fluctuations could provide an ideal substrate for Hebbian reverberations and sensory memory in other neural systems.

Large-scale modular biofiltration system for effective odor removal in a composting facility.

PubMed

Lin, Yueh-Hsien; Chen, Yu-Pei; Ho, Kuo-Ling; Lee, Tsung-Yih; Tseng, Ching-Ping

2013-01-01

Several different foul odors such as nitrogen-containing groups, sulfur-containing groups, and short-chain fatty-acids commonly emitted from composting facilities. In this study, an experimental laboratory-scale bioreactor was scaled up to build a large-scale modular biofiltration system that can process 34 m(3)min(-1)waste gases. This modular reactor system was proven effective in eliminating odors, with a 97% removal efficiency for 96 ppm ammonia, a 98% removal efficiency for 220 ppm amines, and a 100% removal efficiency of other odorous substances. The results of operational parameters indicate that this modular biofiltration system offers long-term operational stability. Specifically, a low pressure drop (<45 mmH2O m(-1)) was observed, indicating that the packing carrier in bioreactor units does not require frequent replacement. Thus, this modular biofiltration system can be used in field applications to eliminate various odors with compact working volume.

I'm no longer torn after choice: how explicit choices implicitly shape preferences of odors.

PubMed

Coppin, Géraldine; Delplanque, Sylvain; Cayeux, Isabelle; Porcherot, Christelle; Sander, David

2010-04-01

Several studies have shown that preferences can be strongly modulated by cognitive processes such as decision making and choices. However, it is still unclear whether choices can influence preferences of sensory stimuli implicitly. This question was addressed here by asking participants to evaluate odors, to choose their preferred odors within pairs, to reevaluate the odors, and to perform an unexpected memory test. Results revealed, for the first time in the study of olfaction, the existence of postchoice preference changes, in the sense of an overvaluation of chosen odors and a devaluation of rejected ones, even when choices were forgotten. These results suggest that chemosensory preferences can be modulated by explicit choices and that such modulation might rely on implicit mechanisms. This finding rules out any explanation of postchoice preference changes in terms of experimental demand and strongly challenges the classical cognitive-dissonance-reduction account of such preference changes.

An assessment of detection canine alerts using flowers that release methyl benzoate, the cocaine odorant, and an evaluation of their behavior in terms of the VOCs produced.

PubMed

Cerreta, Michelle M; Furton, Kenneth G

2015-06-01

In recent years, the high frequency of illicit substance abuse reported in the United States has made the development of efficient and rapid detection methods important. Biological detectors, such as canines (Canis familiaris), are valuable tools for rapid, on-site identification of illicit substances. However, research indicates that in many cases canines do not alert to the contraband, but rather to the volatile organic compounds (VOCs) that are released from the contraband, referred to as the "active odor." In 2013, canine accuracy and reliability were challenged in the Supreme Court case, State of Florida v. Jardines. In this case, it was stated that if a canine alerts to the active odor, and not the contraband, the canine's accuracy and selectivity could be questioned, since many of these compounds have been found in common household products. Specifically, methyl benzoate, the active odor of cocaine, has been found to be the most abundant compound produced by snapdragon flowers. Therefore, the purpose of this study is to evaluate the odor profiles of various species of snapdragon flowers to assess how significantly methyl benzoate contributes to the total VOC profile or fragrance that is produced. Particularly, this study examines the VOCs released from newly grown snapdragon flowers and determines its potential at eliciting a false alert from specially trained detection canines. The ability of detection canines to differentiate between cocaine and snapdragon flowers was determined in order to validate the field accuracy and discrimination power of these detectors. An optimized method using headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME/GC-MS) was used to test the different types and abundances of compounds generated from snapdragon flowers at various stages throughout the plants' life cycle. The results indicate that although methyl benzoate is present in the odor profile of snapdragon flowers, other compounds are present that contribute significantly, if not more, than that of methyl benzoate. Canine teams, from various police departments throughout South Florida, certified for narcotics detection, took part in this study. Two canine trials involving 21 canines teams were performed by exposing the teams to 4 different species of snapdragon flowers. Of the 21 canine teams tested, none alerted to the snapdragon flowers presented, while all (100%) alerted to real cocaine samples, the positive control. Notably, the results revealed that although methyl benzoate is produced by snapdragon flowers, certified narcotics detection canines can distinguish cocaine's odor profile from that of snapdragon flowers. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Sparse Coding and Lateral Inhibition Arising from Balanced and Unbalanced Dendrodendritic Excitation and Inhibition

PubMed Central

Migliore, Michele; Hines, Michael L.; Shepherd, Gordon M.

2014-01-01

The precise mechanism by which synaptic excitation and inhibition interact with each other in odor coding through the unique dendrodendritic synaptic microcircuits present in olfactory bulb is unknown. Here a scaled-up model of the mitral–granule cell network in the rodent olfactory bulb is used to analyze dendrodendritic processing of experimentally determined odor patterns. We found that the interaction between excitation and inhibition is responsible for two fundamental computational mechanisms: (1) a balanced excitation/inhibition in strongly activated mitral cells, leading to a sparse representation of odorant input, and (2) an unbalanced excitation/inhibition (inhibition dominated) in surrounding weakly activated mitral cells, leading to lateral inhibition. These results suggest how both mechanisms can carry information about the input patterns, with optimal level of synaptic excitation and inhibition producing the highest level of sparseness and decorrelation in the network response. The results suggest how the learning process, through the emergent development of these mechanisms, can enhance odor representation of olfactory bulb. PMID:25297097

Role of the fermentation process in off-odorant formation in white pepper: on-site trial in Thailand.

PubMed

Steinhaus, Martin; Schieberle, Peter

2005-07-27

In white pepper samples, directly taken from a retting batch at a pepper production plant in Thailand, 3-methylindole, 4-methylphenol, 3-methylphenol, and butanoic acid, recently confirmed to be responsible for the characteristic fecal off-odor frequently detected in white pepper powders, were quantified by stable isotope dilution analyses. The results clearly showed that, in particular, 3-methylindole (fecal, swine-manure-like), 4-methylphenol (fecal, horse-like), and butanoic acid (cheese-like) were biochemically formed during retting, thus indicating that fermentation is the crucial step for off-odorant formation during white pepper processing. Model fermentation experiments performed with different manufacturing regimens revealed that white pepper, containing no substantial amounts of these odorants, can be produced from ripe starting material by a short fermentation under water and with frequent exchange of water. The overall aroma of such pepper was superior as compared to the aroma of white pepper produced according to the traditional procedure.

Dissecting the signaling mechanisms underlying recognition and preference of food odors.

PubMed

Harris, Gareth; Shen, Yu; Ha, Heonick; Donato, Alessandra; Wallis, Samuel; Zhang, Xiaodong; Zhang, Yun

2014-07-09

Food is critical for survival. Many animals, including the nematode Caenorhabditis elegans, use sensorimotor systems to detect and locate preferred food sources. However, the signaling mechanisms underlying food-choice behaviors are poorly understood. Here, we characterize the molecular signaling that regulates recognition and preference between different food odors in C. elegans. We show that the major olfactory sensory neurons, AWB and AWC, play essential roles in this behavior. A canonical Gα-protein, together with guanylate cyclases and cGMP-gated channels, is needed for the recognition of food odors. The food-odor-evoked signal is transmitted via glutamatergic neurotransmission from AWC and through AMPA and kainate-like glutamate receptor subunits. In contrast, peptidergic signaling is required to generate preference between different food odors while being dispensable for the recognition of the odors. We show that this regulation is achieved by the neuropeptide NLP-9 produced in AWB, which acts with its putative receptor NPR-18, and by the neuropeptide NLP-1 produced in AWC. In addition, another set of sensory neurons inhibits food-odor preference. These mechanistic logics, together with a previously mapped neural circuit underlying food-odor preference, provide a functional network linking sensory response, transduction, and downstream receptors to process complex olfactory information and generate the appropriate behavioral decision essential for survival. Copyright © 2014 the authors 0270-6474/14/339389-15$15.00/0.

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

PubMed

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

2018-05-01

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

The orexin component of fasting triggers memory processes underlying conditioned food selection in the rat.

PubMed

Ferry, Barbara; Duchamp-Viret, Patricia

2014-03-14

To test the selectivity of the orexin A (OXA) system in olfactory sensitivity, the present study compared the effects of fasting and of central infusion of OXA on the memory processes underlying odor-malaise association during the conditioned odor aversion (COA) paradigm. Animals implanted with a cannula in the left ventricle received ICV infusion of OXA or artificial cerebrospinal fluid (ACSF) 1 h before COA acquisition. An additional group of intact rats were food-deprived for 24 h before acquisition. Results showed that the increased olfactory sensitivity induced by fasting and by OXA infusion was accompanied by enhanced COA performance. The present results suggest that fasting-induced central OXA release influenced COA learning by increasing not only olfactory sensitivity, but also the memory processes underlying the odor-malaise association.

Comparison of glomerular activity patterns by fMRI and wide-field calcium imaging: implications for principles underlying odor mapping

PubMed Central

Sanganahalli, Basavaraju G.; Rebello, Michelle R.; Herman, Peter; Papademetris, Xenophon; Shepherd, Gordon M.; Verhagen, Justus V.; Hyder, Fahmeed

2015-01-01

Functional imaging signals arise from distinct metabolic and hemodynamic events at the neuropil, but how these processes are influenced by pre- and post-synaptic activities need to be understood for quantitative interpretation of stimulus-evoked mapping data. The olfactory bulb (OB) glomeruli, spherical neuropil regions with well-defined neuronal circuitry, can provide insights into this issue. Optical calcium-sensitive fluorescent dye imaging (OICa2+) reflects dynamics of pre-synaptic input to glomeruli, whereas high-resolution functional magnetic resonance imaging (fMRI) using deoxyhemoglobin contrast reveals neuropil function within the glomerular layer where both pre- and post-synaptic activities contribute. We imaged odor-specific activity patterns of the dorsal OB in the same anesthetized rats with fMRI and OICa2+ and then co-registered the respective maps to compare patterns in the same space. Maps by each modality were very reproducible as trial-to-trial patterns for a given odor, overlapping by ~80%. Maps evoked by ethyl butyrate and methyl valerate for a given modality overlapped by ~80%, suggesting activation of similar dorsal glomerular networks by these odors. Comparison of maps generated by both methods for a given odor showed ~70% overlap, indicating similar odor-specific maps by each method. These results suggest that odor-specific glomerular patterns by high-resolution fMRI primarily tracks pre-synaptic input to the OB. Thus combining OICa2+ and fMRI lays the framework for studies of OB processing over a range of spatiotemporal scales, where OICa2+ can feature the fast dynamics of dorsal glomerular clusters and fMRI can map the entire glomerular sheet in the OB. PMID:26631819

Access to the odor world: olfactory receptors and their role for signal transduction in insects.

PubMed

Fleischer, Joerg; Pregitzer, Pablo; Breer, Heinz; Krieger, Jürgen

2018-02-01

The sense of smell enables insects to recognize and discriminate a broad range of volatile chemicals in their environment originating from prey, host plants and conspecifics. These olfactory cues are received by olfactory sensory neurons (OSNs) that relay information about food sources, oviposition sites and mates to the brain and thus elicit distinct odor-evoked behaviors. Research over the last decades has greatly advanced our knowledge concerning the molecular basis underlying the reception of odorous compounds and the mechanisms of signal transduction in OSNs. The emerging picture clearly indicates that OSNs of insects recognize odorants and pheromones by means of ligand-binding membrane proteins encoded by large and diverse families of receptor genes. In contrast, the mechanisms of the chemo-electrical transduction process are not fully understood; the present status suggests a contribution of ionotropic as well as metabotropic mechanisms. In this review, we will summarize current knowledge on the peripheral mechanisms of odor sensing in insects focusing on olfactory receptors and their specific role in the recognition and transduction of odorant and pheromone signals by OSNs.

Animal-to-Animal Variation in Odor Preference and Neural Representation of Odors

NASA Astrophysics Data System (ADS)

Honegger, Kyle; Smith, Matthew; Turner, Glenn; de Bivort, Benjamin

Across any population of animals, individuals exhibit diverse behaviors and reactions to sensory stimuli like tastes and odors. While idiosyncratic behavior is ubiquitous, its biological basis is poorly understood. In this talk, I will present evidence that individual fruit flies (Drosophila melanogaster) display idiosyncratic olfactory behaviors and discuss our ongoing efforts to map these behavioral differences to variation in neural circuits. Using a high-throughput, single-fly assay for odor preference, we have demonstrated that highly inbred flies display substantial animal-to-animal variability, beyond that expected from experimental error, and that these preferences persist over days. Using in vivo two-photon calcium imaging, we are beginning to examine the idiosyncrasy of neural coding in the fly olfactory pathway and find that the odor responses of individual processing channels in the antennal lobe can vary substantially from fly to fly. These results imply that individual differences in neural coding may be used to predict the idiosyncratic behavior of an individual - a hypothesis we are currently testing by imaging neural activity from flies after measuring their odor preferences.

Identification of predominant odorants in thai desserts flavored by smoking with "Tian Op", a traditional Thai scented candle.

PubMed

Watcharananun, Wanwarang; Cadwallader, Keith R; Huangrak, Kittiphong; Kim, Hun; Lorjaroenphon, Yaowapa

2009-02-11

"Tian Op", a traditional Thai scented candle, is used for the smoking and flavoring of sweets, cakes, and other desserts for the purpose of adding a unique aroma to the final product. Gas chromatography-olfactometry, aroma extract dilution analysis, and GC-MS were applied to identify the potent odorants in two types of traditional Thai desserts ("num dok mai" and "gleep lum duan") prepared using a Tian Op smoking process. On the basis of the results of AEDA and calculated odor-activity values, the predominant odorants in the Tian Op flavored desserts were vinyl ketones (C(5)-C(9)), n-aldehydes (C(5)-C(11)), (E)-2-unsaturated aldehydes (C(8)-C(11)), and omega-1-unsaturated aldehydes (C(8) and C(9)). Sensory studies of model mixtures confirmed the importance of n-aldehydes, omega-1-unsaturated aldehydes, and guaiacol as predominant odorants; however, the results showed that vinyl ketones and (E)-2-unsaturated aldehydes, despite having high odor-activity values, may be of only minor importance in the typical aroma profiles of traditional Tian Op smoked desserts.

Orbital cortex neuronal responses during an odor-based conditioned associative task in rats.

PubMed

Yonemori, M; Nishijo, H; Uwano, T; Tamura, R; Furuta, I; Kawasaki, M; Takashima, Y; Ono, T

2000-01-01

Neuronal activity in the rat orbital cortex during discrimination of various odors [five volatile organic compounds (acetophenone, isoamyl acetate, cyclohexanone, p-cymene and 1,8-cineole), and food- and cosmetic-related odorants (black pepper, cheese, rose and perfume)] and other conditioned sensory stimuli (tones, light and air puff) was recorded and compared with behavioral responses to the same odors (black pepper, cheese, rose and perfume). In a neurophysiological study, the rats were trained to lick a spout that protruded close to its mouth to obtain sucrose or intracranial self-stimulation reward after presentation of conditioned stimuli. Of 150 orbital cortex neurons recorded during the task, 65 responded to one or more types of sensory stimuli. Of these, 73.8% (48/65) responded during presentation of an odor. Although the mean breadth of responsiveness (entropy) of the olfactory neurons based on the responses to five volatile organic compounds and air (control) was rather high (0.795), these stimuli were well discriminated in an odor space resulting from multidimensional scaling using Pearson's correlation coefficients between the stimuli. In a behavioral study, a rat was housed in an equilateral octagonal cage, with free access to food and choice among eight levers, four of which elicited only water (no odor, controls), and four of which elicited both water and one of four odors (black pepper, cheese, rose or perfume). Lever presses for each odor and control were counted. Distributions of these five stimuli (four odors and air) in an odor space derived from the multidimensional scaling using Pearson's correlation coefficients based on behavioral responses were very similar to those based on neuronal responses to the same five stimuli. Furthermore, Pearson's correlation coefficients between the same five stimuli based on the neuronal responses and those based on behavioral responses were significantly correlated. The results demonstrated a pivotal role of the rat orbital cortex in olfactory sensory processing and suggest that the orbital cortex is important in the manifestation of various motivated behaviors of the animals, including odor-guided motivational behaviors (odor preference).

Analysis of a GC/MS thermal desorption system with simultaneous sniffing for determination of off-odor compounds and VOCs in fumes formed during extrusion coating of low-density polyethylene.

PubMed

Villberg, K; Veijanen, A

2001-03-01

A thermal desorption equipment introducing volatile organic compounds (VOCs) into the gas chromatographic/ mass spectrometric system (GC/MS) with simultaneous sniffing (SNIFF) is a suitable method for identifying the volatile organic off-odor compounds formed during the extrusion coating process of low-density polyethylene. Fumes emitted during the extrusion coating process of three different plastic materials were collected at two different temperatures (285 and 315 degrees C) from an outgoing pipe and near an extruder. The VOCs of fumes were analyzed by drawing a known volume of air through the adsorbent tube filled with a solid adsorbent (Tenax GR). The air samples were analyzed by using a special thermal desorption device and GC/MS determination. The simultaneous sniffing was carried out to detect off-odors and to assist in the identification of those compounds that contribute to tainting and smelling. The amounts of off-odor carbonyl compounds and the total content of the volatile organic compounds were determined. The most odorous compounds were identified as carboxylic acids while the majority of the volatile compounds were hydrocarbons. The detection and quantification of carboxylic acids were based on the characteristic ions of their mass spectra. The higher the extrusion temperature the more odors were detected. An important observation was that the total concentration of volatiles was dependent not only on the extrusion temperature but also on the plastic material.

The banana code-natural blend processing in the olfactory circuitry of Drosophila melanogaster.

PubMed

Schubert, Marco; Hansson, Bill S; Sachse, Silke

2014-01-01

Odor information is predominantly perceived as complex odor blends. For Drosophila melanogaster one of the most attractive blends is emitted by an over-ripe banana. To analyze how the fly's olfactory system processes natural blends we combined the experimental advantages of gas chromatography and functional imaging (GC-I). In this way, natural banana compounds were presented successively to the fly antenna in close to natural occurring concentrations. This technique allowed us to identify the active odor components, use these compounds as stimuli and measure odor-induced Ca(2+) signals in input and output neurons of the Drosophila antennal lobe (AL), the first olfactory neuropil. We demonstrate that mixture interactions of a natural blend are very rare and occur only at the AL output level resulting in a surprisingly linear blend representation. However, the information regarding single components is strongly modulated by the olfactory circuitry within the AL leading to a higher similarity between the representation of individual components and the banana blend. This observed modulation might tune the olfactory system in a way to distinctively categorize odor components and improve the detection of suitable food sources. Functional GC-I thus enables analysis of virtually any unknown natural odorant blend and its components in their relative occurring concentrations and allows characterization of neuronal responses of complete neural assemblies. This technique can be seen as a valuable complementary method to classical GC/electrophysiology techniques, and will be a highly useful tool in future investigations of insect-insect and insect-plant chemical interactions.

Peripheral adaptive filtering in human olfaction? Three studies on prevalence and effects of olfactory training in specific anosmia in more than 1600 participants.

PubMed

Croy, Ilona; Olgun, Selda; Mueller, Laura; Schmidt, Anna; Muench, Marcus; Hummel, Cornelia; Gisselmann, Guenter; Hatt, Hanns; Hummel, Thomas

2015-12-01

Selective processing of environmental stimuli improves processing capacity and allows adaptive modulation of behavior. The thalamus provides an effective filter of central sensory information processing. As olfactory projections, however, largely bypass the thalamus, other filter mechanisms must consequently have evolved for the sense of smell. We investigated whether specific anosmia - the inability to perceive a specific odor whereas detection of other substances is unaffected - represents an effective peripheral filter of olfactory information processing. In contrast to previous studies, we showed in a sample of 1600 normosmic subjects, that specific anosmia is by no means a rare phenomenon. Instead, while the affected odor is highly individual, the general probability of occurrence of specific anosmia is close to 1. In addition, 25 subjects performed daily olfactory training sessions with enhanced exposure to their particular "missing" smells for the duration of three months. This resulted in a significant improvement of sensitivity towards the respective specific odors. We propose specific anosmia to occur as a rule, rather than an exception, in the sense of smell. The lack of perception of certain odors may constitute a flexible peripheral filter mechanism, which can be altered by exposure. Copyright © 2015 Elsevier Ltd. All rights reserved.

Calcium dynamics regulating the timing of decision-making in C. elegans.

PubMed

Tanimoto, Yuki; Yamazoe-Umemoto, Akiko; Fujita, Kosuke; Kawazoe, Yuya; Miyanishi, Yosuke; Yamazaki, Shuhei J; Fei, Xianfeng; Busch, Karl Emanuel; Gengyo-Ando, Keiko; Nakai, Junichi; Iino, Yuichi; Iwasaki, Yuishi; Hashimoto, Koichi; Kimura, Koutarou D

2017-05-23

Brains regulate behavioral responses with distinct timings. Here we investigate the cellular and molecular mechanisms underlying the timing of decision-making during olfactory navigation in Caenorhabditis elegans . We find that, based on subtle changes in odor concentrations, the animals appear to choose the appropriate migratory direction from multiple trials as a form of behavioral decision-making. Through optophysiological, mathematical and genetic analyses of neural activity under virtual odor gradients, we further find that odor concentration information is temporally integrated for a decision by a gradual increase in intracellular calcium concentration ([Ca 2+ ] i ), which occurs via L-type voltage-gated calcium channels in a pair of olfactory neurons. In contrast, for a reflex-like behavioral response, [Ca 2+ ] i rapidly increases via multiple types of calcium channels in a pair of nociceptive neurons. Thus, the timing of neuronal responses is determined by cell type-dependent involvement of calcium channels, which may serve as a cellular basis for decision-making.

Calcium dynamics regulating the timing of decision-making in C. elegans

PubMed Central

Tanimoto, Yuki; Yamazoe-Umemoto, Akiko; Fujita, Kosuke; Kawazoe, Yuya; Miyanishi, Yosuke; Yamazaki, Shuhei J; Fei, Xianfeng; Busch, Karl Emanuel; Gengyo-Ando, Keiko; Nakai, Junichi; Iino, Yuichi; Iwasaki, Yuishi; Hashimoto, Koichi; Kimura, Koutarou D

2017-01-01

Brains regulate behavioral responses with distinct timings. Here we investigate the cellular and molecular mechanisms underlying the timing of decision-making during olfactory navigation in Caenorhabditis elegans. We find that, based on subtle changes in odor concentrations, the animals appear to choose the appropriate migratory direction from multiple trials as a form of behavioral decision-making. Through optophysiological, mathematical and genetic analyses of neural activity under virtual odor gradients, we further find that odor concentration information is temporally integrated for a decision by a gradual increase in intracellular calcium concentration ([Ca2+]i), which occurs via L-type voltage-gated calcium channels in a pair of olfactory neurons. In contrast, for a reflex-like behavioral response, [Ca2+]i rapidly increases via multiple types of calcium channels in a pair of nociceptive neurons. Thus, the timing of neuronal responses is determined by cell type-dependent involvement of calcium channels, which may serve as a cellular basis for decision-making. DOI: http://dx.doi.org/10.7554/eLife.21629.001 PMID:28532547

A green procedure using ozone for Cleaning-in-Place in the beverage industry.

PubMed

Nishijima, Wataru; Okuda, Tetsuji; Nakai, Satoshi; Okada, Mitsumasa

2014-06-01

Cleaning-in-Place (CIP) in the beverage industry is typically carried out in production lines with alkaline and acidic solutions with detergents. This cleaning not only produces alkaline and acidic wastewater with detergents but also takes significant time. One of the important targets for CIP is adsorbed odorous compounds on gaskets, hence, we have tried to establish a rapid and green CIP process to remove traces of such compounds, especially d-limonene, an odorous component of orange juice, using two approaches; an ozone cleaning method and a change of gasket material from ethylene propylene diene monomer (EPDM) rubber to silicone rubber. By changing the gasket material from EPDM rubber to silicone rubber, the removability of d-limonene by typical alkaline and acidic cleanings with detergents was improved. However, complete removal of 4 mg g(-1) of d-limonene on both EPDM and silicone gaskets could not be achieved even using a series of conventional cleaning procedures that included alkaline and acidic cleaning for 220 min. Ozone treatment dramatically improved the removability of d-limonene, removing 87% from the EPDM gasket at 60 min and 100% from the silicone gasket at 30 min. The combination of the silicone gasket and ozone treatment resulted in the most effective cleaning. The main removal mechanism for ozone treatment was confirmed to be oxidation by molecular ozone. Effectiveness of changing the gasket material from EPDM rubber to silicone rubber in reducing residual amounts of odorous compounds adsorbed on the gaskets was also confirmed for furfural and 4-vinylguaiacol. Copyright © 2014 Elsevier Ltd. All rights reserved.

Sampling Technique for Robust Odorant Detection Based on MIT RealNose Data

NASA Technical Reports Server (NTRS)

Duong, Tuan A.

2012-01-01

This technique enhances the detection capability of the autonomous Real-Nose system from MIT to detect odorants and their concentrations in noisy and transient environments. The lowcost, portable system with low power consumption will operate at high speed and is suited for unmanned and remotely operated long-life applications. A deterministic mathematical model was developed to detect odorants and calculate their concentration in noisy environments. Real data from MIT's NanoNose was examined, from which a signal conditioning technique was proposed to enable robust odorant detection for the RealNose system. Its sensitivity can reach to sub-part-per-billion (sub-ppb). A Space Invariant Independent Component Analysis (SPICA) algorithm was developed to deal with non-linear mixing that is an over-complete case, and it is used as a preprocessing step to recover the original odorant sources for detection. This approach, combined with the Cascade Error Projection (CEP) Neural Network algorithm, was used to perform odorant identification. Signal conditioning is used to identify potential processing windows to enable robust detection for autonomous systems. So far, the software has been developed and evaluated with current data sets provided by the MIT team. However, continuous data streams are made available where even the occurrence of a new odorant is unannounced and needs to be noticed by the system autonomously before its unambiguous detection. The challenge for the software is to be able to separate the potential valid signal from the odorant and from the noisy transition region when the odorant is just introduced.

Characterization of Key Aroma Compounds in Raw and Thermally Processed Prawns and Thermally Processed Lobsters by Application of Aroma Extract Dilution Analysis.

PubMed

Mall, Veronika; Schieberle, Peter

2016-08-24

Application of aroma extract dilution analysis (AEDA) to an aroma distillate of blanched prawn meat (Litopenaeus vannamei) (BPM) revealed 40 odorants in the flavor dilution (FD) factor range from 4 to 1024. The highest FD factors were assigned to 2-acetyl-1-pyrroline, 3-(methylthio)propanal, (Z)-1,5-octadien-3-one, trans-4,5-epoxy-(E)-2-decenal, (E)-3-heptenoic acid, and 2-aminoacetophenone. To understand the influence of different processing conditions on odorant formation, fried prawn meat was investigated by means of AEDA in the same way, revealing 31 odorants with FD factors between 4 and 2048. Also, the highest FD factors were determined for 2-acetyl-1-pyrroline, 3-(methylthio)propanal, and (Z)-1,5-octadien-3-one, followed by 4-hydroxy-2,5-dimethyl-3(2H)-furanone, (E)-3-heptenoic acid, and 2-aminoacetophenone. As a source of the typical marine, sea breeze-like odor attribute of the seafood, 2,4,6-tribromoanisole was identified in raw prawn meat as one of the contributors. Additionally, the aroma of blanched prawn meat was compared to that of blanched Norway and American lobster meat, respectively (Nephrops norvegicus and Homarus americanus). Identification experiments revealed the same set of odorants, however, with differing FD factors. In particular, 3-hydroxy-4,5-dimethyl-2(5H)-furanone was found as the key aroma compound in blanched Norway lobster, whereas American lobster contained 3-methylindole with a high FD factor.

THE ACCELERATION OF THE AGING PROCESS OF ALCOHOLIC BEVERAGES BY $gamma$- IRRADIATION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sumiki, Y.

Using gamma irradiation, the aging of alcoholic beverages can be accelerated. Plain Japanese sake can be aged within l hr with a Co/sup 60/ source of 270 c (total dose l0,000 r). The taste and flavor of fresh sake can be improved with a few thousand r irr-adiation. The unpleasant flavor of poor grade sake and the yeast taste of new sake can be eliminated by irradiation. For natur-ally aged sake and compound sake, the change was very little for a dosage of l0,000 r, and beyond this limit the irradiated sakes were over-aged. For both aged sake and newmore » sake, undesirable tastes were detected for an irradiation dosage greater than 20,000 r. When the dosage approached l00,000 r, the typical irradiation odor'' was detected. Therefore, the ideal dosage range is from several thousand r to l04 r. At an irradiation dosage of l0,000 r, whisky and brandy were aged r-apidly. However, the color was somewhat faded. Distilled Japanese sakes were improved by ir-radiation, but excess irradiation caused undesirable aldehyde odors. (OID)« less

Stable Odor Recognition by a neuro-adaptive Electronic Nose

PubMed Central

Martinelli, Eugenio; Magna, Gabriele; Polese, Davide; Vergara, Alexander; Schild, Detlev; Di Natale, Corrado

2015-01-01

Sensitivity, selectivity and stability are decisive properties of sensors. In chemical gas sensors odor recognition can be severely compromised by poor signal stability, particularly in real life applications where the sensors are exposed to unpredictable sequences of odors under changing external conditions. Although olfactory receptor neurons in the nose face similar stimulus sequences under likewise changing conditions, odor recognition is very stable and odorants can be reliably identified independently from past odor perception. We postulate that appropriate pre-processing of the output signals of chemical sensors substantially contributes to the stability of odor recognition, in spite of marked sensor instabilities. To investigate this hypothesis, we use an adaptive, unsupervised neural network inspired by the glomerular input circuitry of the olfactory bulb. Essentially the model reduces the effect of the sensors’ instabilities by utilizing them via an adaptive multicompartment feed-forward inhibition. We collected and analyzed responses of a 4 × 4 gas sensor array to a number of volatile compounds applied over a period of 18 months, whereby every sensor was sampled episodically. The network conferred excellent stability to the compounds’ identification and was clearly superior over standard classifiers, even when one of the sensors exhibited random fluctuations or stopped working at all. PMID:26043043

Evaluation of the key aroma compounds in beef and pork vegetable gravies a la chef by stable isotope dilution assays and aroma recombination experiments.

PubMed

Christlbauer, Monika; Schieberle, Peter

2011-12-28

Although the aroma compounds of meat processed as such have been studied previously, data on complete homemade dishes containing beef and pork meat were scarcely studied. Recently, 38 odor-active compounds were characterized in beef and pork vegetable gravies using GC-olfactometry. In the present investigation, the most odor-active compounds were quantitated in a freshly prepared stewed beef vegetable gravy (BVG) as well as a stewed pork vegetable gravy (PVG) by means of stable isotope dilution assays. Calculation of odor activity values (OAVs; ratio of concentration to odor threshold) revealed 3-mercapto-2-methylpentan-1-ol, (E,E)-2,4-decadienal, (E,Z)-2,6-nonadienal, (E)-2-decenal, (E)-2-undecanal, and 3-hydroxy-4,5-dimethyl-2(5H)-furanone as the most potent odorants in both gravies. However, significantly different OAVs were found for 12-methyltridecanal, which was much higher in the BVG, whereas (E,Z)-2,4-decadienal showed a clearly higher OAV in the PVG. Aroma recombination experiments performed on the basis of the actual concentrations of the odorants in both gravies revealed a good similarity of the aromas of both model mixtures containing all odorants with OAVs > 1 with those of the original gravies.

Flavor-Enhanced Modulation of Cerebral Blood Flow during Gum Chewing

PubMed Central

Hasegawa, Yoko; Tachibana, Yoshihisa; Sakagami, Joe; Zhang, Min; Urade, Masahiro; Ono, Takahiro

2013-01-01

Background Flavor perception, the integration of taste and odor, is a critical factor in eating behavior. It remains unclear how such sensory signals influence the human brain systems that execute the eating behavior. Methods We tested cerebral blood flow (CBF) in the frontal lobes bilaterally while subjects chewed three types of gum with different combinations of taste and odor: no taste/no odor gum (C-gum), sweet taste/no odor gum (T-gum), and sweet taste/lemon odor gum (TO-gum). Simultaneous recordings of transcranial Doppler ultrasound (TCD) and near infrared spectrometer (NIRS) were used to measure CBF during gum chewing in 25 healthy volunteers. Bilateral masseter muscle activity was also monitored. Results We found that subjects could discriminate the type of gum without prior information. Subjects rated the TO-gum as the most flavorful gum and the C-gum as the least flavorful. Analysis of masseter muscle activity indicated that masticatory motor output during gum chewing was not affected by taste and odor. The TCD/NIRS measurements revealed significantly higher hemodynamic signals when subjects chewed the TO-gum compared to when they chewed the C-gum and T-gum. Conclusions These data suggest that taste and odor can influence brain activation during chewing in sensory, cognitive, and motivational processes rather than in motor control. PMID:23840440

Flavor-Enhanced Modulation of Cerebral Blood Flow during Gum Chewing.

PubMed

Hasegawa, Yoko; Tachibana, Yoshihisa; Sakagami, Joe; Zhang, Min; Urade, Masahiro; Ono, Takahiro

2013-01-01

Flavor perception, the integration of taste and odor, is a critical factor in eating behavior. It remains unclear how such sensory signals influence the human brain systems that execute the eating behavior. WE TESTED CEREBRAL BLOOD FLOW (CBF) IN THE FRONTAL LOBES BILATERALLY WHILE SUBJECTS CHEWED THREE TYPES OF GUM WITH DIFFERENT COMBINATIONS OF TASTE AND ODOR: no taste/no odor gum (C-gum), sweet taste/no odor gum (T-gum), and sweet taste/lemon odor gum (TO-gum). Simultaneous recordings of transcranial Doppler ultrasound (TCD) and near infrared spectrometer (NIRS) were used to measure CBF during gum chewing in 25 healthy volunteers. Bilateral masseter muscle activity was also monitored. We found that subjects could discriminate the type of gum without prior information. Subjects rated the TO-gum as the most flavorful gum and the C-gum as the least flavorful. Analysis of masseter muscle activity indicated that masticatory motor output during gum chewing was not affected by taste and odor. The TCD/NIRS measurements revealed significantly higher hemodynamic signals when subjects chewed the TO-gum compared to when they chewed the C-gum and T-gum. These data suggest that taste and odor can influence brain activation during chewing in sensory, cognitive, and motivational processes rather than in motor control.

Weaker Ligands Can Dominate an Odor Blend due to Syntopic Interactions

PubMed Central

2013-01-01

Most odors in natural environments are mixtures of several compounds. Perceptually, these can blend into a new “perfume,” or some components may dominate as elements of the mixture. In order to understand such mixture interactions, it is necessary to study the events at the olfactory periphery, down to the level of single-odorant receptor cells. Does a strong ligand present at a low concentration outweigh the effect of weak ligands present at high concentrations? We used the fruit fly receptor dOr22a and a banana-like odor mixture as a model system. We show that an intermediate ligand at an intermediate concentration alone elicits the neuron’s blend response, despite the presence of both weaker ligands at higher concentration, and of better ligands at lower concentration in the mixture. Because all of these components, when given alone, elicited significant responses, this reveals specific mixture processing already at the periphery. By measuring complete dose–response curves we show that these mixture effects can be fully explained by a model of syntopic interaction at a single-receptor binding site. Our data have important implications for how odor mixtures are processed in general, and what preprocessing occurs before the information reaches the brain. PMID:23315042

49 CFR 192.625 - Odorization of gas.

Code of Federal Regulations, 2010 CFR

2010-10-01

...; (iii) A gas dehydration plant; or (iv) An industrial plant using gas in a process where the presence of... 49 Transportation 3 2010-10-01 2010-10-01 false Odorization of gas. 192.625 Section 192.625... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF NATURAL AND OTHER GAS...

9 CFR 590.539 - Defrosting operations.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 590.539 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE EGG... objectionable odors and are unfit for human food (e.g., sour, musty, fermented, or decomposed odors) shall be.... Defrosted liquid shall not be held more than 16 hours prior to processing or drying. (e) Sanitary methods...

Spike-Timing of Orbitofrontal Neurons Is Synchronized With Breathing.

PubMed

Kőszeghy, Áron; Lasztóczi, Bálint; Forro, Thomas; Klausberger, Thomas

2018-01-01

The orbitofrontal cortex (OFC) has been implicated in a multiplicity of complex brain functions, including representations of expected outcome properties, post-decision confidence, momentary food-reward values, complex flavors and odors. As breathing rhythm has an influence on odor processing at primary olfactory areas, we tested the hypothesis that it may also influence neuronal activity in the OFC, a prefrontal area involved also in higher order processing of odors. We recorded spike timing of orbitofrontal neurons as well as local field potentials (LFPs) in awake, head-fixed mice, together with the breathing rhythm. We observed that a large majority of orbitofrontal neurons showed robust phase-coupling to breathing during immobility and running. The phase coupling of action potentials to breathing was significantly stronger in orbitofrontal neurons compared to cells in the medial prefrontal cortex. The characteristic synchronization of orbitofrontal neurons with breathing might provide a temporal framework for multi-variable processing of olfactory, gustatory and reward-value relationships.

A Comprehensive Review of Topical Odor-Controlling Treatment Options for Chronic Wounds

PubMed Central

Akhmetova, Alma; Allan, Iain U.; Illsley, Matthew J.; Nurgozhin, Talgat; Mikhalovsky, Sergey

2016-01-01

The process of wound healing is often accompanied by bacterial infection or critical colonization, resulting in protracted inflammation, delayed reepithelization, and production of pungent odors. The malodor produced by these wounds may lower health-related quality of life and produce psychological discomfort and social isolation. Current management focuses on reducing bacterial activity within the wound site and absorbing malodorous gases. For example, charcoal-based materials have been incorporated into dressing for direct adsorption of the responsible gases. In addition, multiple topical agents, including silver, iodine, honey, sugar, and essential oils, have been suggested for incorporation into dressings in an attempt to control the underlying bacterial infection. This review describes options for controlling malodor in chronic wounds, the benefits and drawbacks of each topical agent, and their mode of action. We also discuss the use of subjective odor evaluation techniques to assess the efficacy of odor-controlling therapies. The perspectives of employing novel biomaterials and technologies for wound odor management are also presented. PMID:27684356

A Comprehensive Review of Topical Odor-Controlling Treatment Options for Chronic Wounds.

PubMed

Akhmetova, Alma; Saliev, Timur; Allan, Iain U; Illsley, Matthew J; Nurgozhin, Talgat; Mikhalovsky, Sergey

The process of wound healing is often accompanied by bacterial infection or critical colonization, resulting in protracted inflammation, delayed reepithelization, and production of pungent odors. The malodor produced by these wounds may lower health-related quality of life and produce psychological discomfort and social isolation. Current management focuses on reducing bacterial activity within the wound site and absorbing malodorous gases. For example, charcoal-based materials have been incorporated into dressing for direct adsorption of the responsible gases. In addition, multiple topical agents, including silver, iodine, honey, sugar, and essential oils, have been suggested for incorporation into dressings in an attempt to control the underlying bacterial infection. This review describes options for controlling malodor in chronic wounds, the benefits and drawbacks of each topical agent, and their mode of action. We also discuss the use of subjective odor evaluation techniques to assess the efficacy of odor-controlling therapies. The perspectives of employing novel biomaterials and technologies for wound odor management are also presented.

Ability of human oral microbiota to produce wine odorant aglycones from odourless grape glycosidic aroma precursors.

PubMed

Muñoz-González, Carolina; Cueva, Carolina; Ángeles Pozo-Bayón, M; Victoria Moreno-Arribas, M

2015-11-15

Grape aroma precursors are odourless glycosides that represent a natural reservoir of potential active odorant molecules in wines. Since the first step of wine consumption starts in the oral cavity, the processing of these compounds in the mouth could be an important factor in influencing aroma perception. Therefore, the objective of this work has been to evaluate the ability of human oral microbiota to produce wine odorant aglycones from odourless grape glycosidic aroma precursors previously isolated from white grapes. To do so, two methodological approaches involving the use of typical oral bacteria or the whole oral microbiota isolated from human saliva were followed. Odorant aglycones released in the culture mediums were isolated and analysed by HS-SPME-GC/MS. Results showed the ability of oral bacteria to hydrolyse grape aroma precursors, releasing different types of odorant molecules (terpenes, benzenic compounds and lipid derivatives). The hydrolytic activity seemed to be bacteria-dependent and was subject to large inter-individual variability. Copyright © 2015 Elsevier Ltd. All rights reserved.

A designated odor-language integration system in the human brain.

PubMed

Olofsson, Jonas K; Hurley, Robert S; Bowman, Nicholas E; Bao, Xiaojun; Mesulam, M-Marsel; Gottfried, Jay A

2014-11-05

Odors are surprisingly difficult to name, but the mechanism underlying this phenomenon is poorly understood. In experiments using event-related potentials (ERPs) and functional magnetic resonance imaging (fMRI), we investigated the physiological basis of odor naming with a paradigm where olfactory and visual object cues were followed by target words that either matched or mismatched the cue. We hypothesized that word processing would not only be affected by its semantic congruency with the preceding cue, but would also depend on the cue modality (olfactory or visual). Performance was slower and less precise when linking a word to its corresponding odor than to its picture. The ERP index of semantic incongruity (N400), reflected in the comparison of nonmatching versus matching target words, was more constrained to posterior electrode sites and lasted longer on odor-cue (vs picture-cue) trials. In parallel, fMRI cross-adaptation in the right orbitofrontal cortex (OFC) and the left anterior temporal lobe (ATL) was observed in response to words when preceded by matching olfactory cues, but not by matching visual cues. Time-series plots demonstrated increased fMRI activity in OFC and ATL at the onset of the odor cue itself, followed by response habituation after processing of a matching (vs nonmatching) target word, suggesting that predictive perceptual representations in these regions are already established before delivery and deliberation of the target word. Together, our findings underscore the modality-specific anatomy and physiology of object identification in the human brain. Copyright © 2014 the authors 0270-6474/14/3414864-10$15.00/0.

The banana code—natural blend processing in the olfactory circuitry of Drosophila melanogaster

PubMed Central

Schubert, Marco; Hansson, Bill S.; Sachse, Silke

2014-01-01

Odor information is predominantly perceived as complex odor blends. For Drosophila melanogaster one of the most attractive blends is emitted by an over-ripe banana. To analyze how the fly's olfactory system processes natural blends we combined the experimental advantages of gas chromatography and functional imaging (GC-I). In this way, natural banana compounds were presented successively to the fly antenna in close to natural occurring concentrations. This technique allowed us to identify the active odor components, use these compounds as stimuli and measure odor-induced Ca2+ signals in input and output neurons of the Drosophila antennal lobe (AL), the first olfactory neuropil. We demonstrate that mixture interactions of a natural blend are very rare and occur only at the AL output level resulting in a surprisingly linear blend representation. However, the information regarding single components is strongly modulated by the olfactory circuitry within the AL leading to a higher similarity between the representation of individual components and the banana blend. This observed modulation might tune the olfactory system in a way to distinctively categorize odor components and improve the detection of suitable food sources. Functional GC-I thus enables analysis of virtually any unknown natural odorant blend and its components in their relative occurring concentrations and allows characterization of neuronal responses of complete neural assemblies. This technique can be seen as a valuable complementary method to classical GC/electrophysiology techniques, and will be a highly useful tool in future investigations of insect-insect and insect-plant chemical interactions. PMID:24600405

The cyclic nucleotide gated channel subunit CNG-1 instructs behavioral outputs in Caenorhabditis elegans by coincidence detection of nutritional status and olfactory input.

PubMed

He, Chao; Altshuler-Keylin, Svetlana; Daniel, David; L'Etoile, Noelle D; O'Halloran, Damien

2016-10-06

In mammals, olfactory subsystems have been shown to express seven-transmembrane G-protein-coupled receptors (GPCRs) in a one-receptor-one-neuron pattern, whereas in Caenorhabditis elegans, olfactory sensory neurons express multiple G-protein coupled odorant receptors per olfactory sensory neuron. In both mammalian and C. elegans olfactory sensory neurons (OSNs), the process of olfactory adaptation begins within the OSN; this process of negative feedback within the mammalian OSN has been well described in mammals and enables activated OSNs to desensitize their response cell autonomously while attending to odors detected by separate OSNs. However, the mechanism that enables C. elegans to adapt to one odor and attend to another odor sensed by the same olfactory sensory neuron remains unclear. We found that the cyclic nucleotide gated channel subunit CNG-1 is required to promote cross adaptation responses between distinct olfactory cues. This change in sensitivity to a pair of odorants after persistent stimulation by just one of these odors is modulated by the internal nutritional state of the animal, and we find that this response is maintained across a diverse range of food sources for C. elegans. We also reveal that CNG-1 integrates food related cues for exploratory motor output, revealing that CNG-1 functions in multiple capacities to link nutritional information with behavioral output. Our data describes a novel model whereby CNG channels can integrate the coincidence detection of appetitive and olfactory information to set olfactory preferences and instruct behavioral outputs. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

History dependence in insect flight decisions during odor tracking.

PubMed

Pang, Rich; van Breugel, Floris; Dickinson, Michael; Riffell, Jeffrey A; Fairhall, Adrienne

2018-02-01

Natural decision-making often involves extended decision sequences in response to variable stimuli with complex structure. As an example, many animals follow odor plumes to locate food sources or mates, but turbulence breaks up the advected odor signal into intermittent filaments and puffs. This scenario provides an opportunity to ask how animals use sparse, instantaneous, and stochastic signal encounters to generate goal-oriented behavioral sequences. Here we examined the trajectories of flying fruit flies (Drosophila melanogaster) and mosquitoes (Aedes aegypti) navigating in controlled plumes of attractive odorants. While it is known that mean odor-triggered flight responses are dominated by upwind turns, individual responses are highly variable. We asked whether deviations from mean responses depended on specific features of odor encounters, and found that odor-triggered turns were slightly but significantly modulated by two features of odor encounters. First, encounters with higher concentrations triggered stronger upwind turns. Second, encounters occurring later in a sequence triggered weaker upwind turns. To contextualize the latter history dependence theoretically, we examined trajectories simulated from three normative tracking strategies. We found that neither a purely reactive strategy nor a strategy in which the tracker learned the plume centerline over time captured the observed history dependence. In contrast, "infotaxis", in which flight decisions maximized expected information gain about source location, exhibited a history dependence aligned in sign with the data, though much larger in magnitude. These findings suggest that while true plume tracking is dominated by a reactive odor response it might also involve a history-dependent modulation of responses consistent with the accumulation of information about a source over multi-encounter timescales. This suggests that short-term memory processes modulating decision sequences may play a role in natural plume tracking.

History dependence in insect flight decisions during odor tracking

PubMed Central

van Breugel, Floris; Dickinson, Michael; Riffell, Jeffrey A.; Fairhall, Adrienne

2018-01-01

Natural decision-making often involves extended decision sequences in response to variable stimuli with complex structure. As an example, many animals follow odor plumes to locate food sources or mates, but turbulence breaks up the advected odor signal into intermittent filaments and puffs. This scenario provides an opportunity to ask how animals use sparse, instantaneous, and stochastic signal encounters to generate goal-oriented behavioral sequences. Here we examined the trajectories of flying fruit flies (Drosophila melanogaster) and mosquitoes (Aedes aegypti) navigating in controlled plumes of attractive odorants. While it is known that mean odor-triggered flight responses are dominated by upwind turns, individual responses are highly variable. We asked whether deviations from mean responses depended on specific features of odor encounters, and found that odor-triggered turns were slightly but significantly modulated by two features of odor encounters. First, encounters with higher concentrations triggered stronger upwind turns. Second, encounters occurring later in a sequence triggered weaker upwind turns. To contextualize the latter history dependence theoretically, we examined trajectories simulated from three normative tracking strategies. We found that neither a purely reactive strategy nor a strategy in which the tracker learned the plume centerline over time captured the observed history dependence. In contrast, “infotaxis”, in which flight decisions maximized expected information gain about source location, exhibited a history dependence aligned in sign with the data, though much larger in magnitude. These findings suggest that while true plume tracking is dominated by a reactive odor response it might also involve a history-dependent modulation of responses consistent with the accumulation of information about a source over multi-encounter timescales. This suggests that short-term memory processes modulating decision sequences may play a role in natural plume tracking. PMID:29432454

Temporal Processing in the Olfactory System: Can We See a Smell?

PubMed Central

Gire, David H.; Restrepo, Diego; Sejnowski, Terrence J.; Greer, Charles; De Carlos, Juan A.; Lopez-Mascaraque, Laura

2013-01-01

Sensory processing circuits in the visual and olfactory systems receive input from complex, rapidly changing environments. Although patterns of light and plumes of odor create different distributions of activity in the retina and olfactory bulb, both structures use what appears on the surface similar temporal coding strategies to convey information to higher areas in the brain. We compare temporal coding in the early stages of the olfactory and visual systems, highlighting recent progress in understanding the role of time in olfactory coding during active sensing by behaving animals. We also examine studies that address the divergent circuit mechanisms that generate temporal codes in the two systems, and find that they provide physiological information directly related to functional questions raised by neuroanatomical studies of Ramon y Cajal over a century ago. Consideration of differences in neural activity in sensory systems contributes to generating new approaches to understand signal processing. PMID:23664611

Kinase Activity in the Olfactory Bulb Is Required for Odor Memory Consolidation

ERIC Educational Resources Information Center

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

2018-01-01

Long-term fear memory formation in the hippocampus and neocortex depends upon brain-derived neurotrophic factor (BDNF) signaling after acquisition. Incremental, appetitive odor discrimination learning is thought to depend substantially on the differentiation of adult-born neurons within the olfactory bulb (OB)--a process that is closely associated…

A "green process" for producing highly purified zein from commercial zein

USDA-ARS?s Scientific Manuscript database

Corn zein is the major protein component of ground corn, and co-products of the corn ethanol industry which includes corn gluten meal and distillers’ dried grains. Zein products generated from those co-products all possess yellow coloration and off-odor. Removal of yellow color and off-odor is essen...

Optimization of biological and instrumental detection of explosives and ignitable liquid residues including canines, SPME/ITMS and GC/MSn

NASA Astrophysics Data System (ADS)

Furton, Kenneth G.; Harper, Ross J.; Perr, Jeannette M.; Almirall, Jose R.

2003-09-01

A comprehensive study and comparison is underway using biological detectors and instrumental methods for the rapid detection of ignitable liquid residues (ILR) and high explosives. Headspace solid phase microextraction (SPME) has been demonstrated to be an effective sampling method helping to identify active odor signature chemicals used by detector dogs to locate forensic specimens as well as a rapid pre-concentration technique prior to instrumental detection. Common ignitable liquids and common military and industrial explosives have been studied including trinitrotoluene, tetryl, RDX, HMX, EGDN, PETN and nitroglycerine. This study focuses on identifying volatile odor signature chemicals present, which can be used to enhance the level and reliability of detection of ILR and explosives by canines and instrumental methods. While most instrumental methods currently in use focus on particles and on parent organic compounds, which are often involatile, characteristic volatile organics are generally also present and can be exploited to enhance detection particularly for well-concealed devices. Specific examples include the volatile odor chemicals 2-ethyl-1-hexanol and cyclohexanone, which are readily available in the headspace of the high explosive composition C-4; whereas, the active chemical cyclo-1,3,5-trimethylene-2,4,6-trinitramine (RDX) is not. The analysis and identification of these headspace 'fingerprint' organics is followed by double-blind dog trials of the individual components using certified teams in an attempt to isolate and understand the target compounds to which dogs are sensitive. Studies to compare commonly used training aids with the actual target explosive have also been undertaken to determine their suitability and effectiveness. The optimization of solid phase microextraction (SPME) combined with ion trap mobility spectrometry (ITMS) and gas chromatography/mass spectrometry/mass spectrometry (GC/MSn) is detailed including interface development and comparisons of limits of detection. These instrumental methods are being optimized in order to detect the same target odor chemicals used by detector dogs to reliably locate explosives and ignitable liquids.

Home-cage odors spatial cues elicit theta phase/gamma amplitude coupling between olfactory bulb and dorsal hippocampus.

PubMed

Pena, Roberta Ribas; Medeiros, Daniel de Castro; Guarnieri, Leonardo de Oliveira; Guerra, Julio Boriollo; Carvalho, Vinícius Rezende; Mendes, Eduardo Mazoni Andrade Marçal; Pereira, Grace Schenatto; Moraes, Márcio Flávio Dutra

2017-11-05

The brain oscillations may play a critical role in synchronizing neuronal assemblies in order to establish appropriate sensory-motor integration. In fact, studies have demonstrated phase-amplitude coupling of distinct oscillatory rhythms during cognitive processes. Here we investigated whether olfacto-hippocampal coupling occurs when mice are detecting familiar odors located in a spatially restricted area of a new context. The spatial olfactory task (SOT) was designed to expose mice to a new environment in which only one quadrant (target) contains odors provided by its own home-cage bedding. As predicted, mice showed a significant higher exploration preference to the target quadrant; which was impaired by olfactory epithelium lesion (ZnSO 4 ). Furthermore, mice were able to discriminate odors from a different cage and avoided the quadrant with predator odor 2,4,5-trimethylthiazoline (TMT), reinforcing the specificity of the SOT. The local field potential (LFP) analysis of non-lesioned mice revealed higher gamma activity (35-100Hz) in the main olfactory bulb (MOB) and a significant theta phase/gamma amplitude coupling between MOB and dorsal hippocampus, only during exploration of home-cage odors (i.e. in the target quadrant). Our results suggest that exploration of familiar odors in a new context involves dynamic coupling between the olfactory bulb and dorsal hippocampus. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

Characterization of the Potent Odorants Contributing to the Characteristic Aroma of Matcha by Gas Chromatography-Olfactometry Techniques.

PubMed

Baba, Ryoko; Amano, Yohei; Wada, Yoshiyuki; Kumazawa, Kenji

2017-03-31

The odorants contributing to the characteristic aroma of matcha were investigated by analysis of the headspace samples and the volatile fractions prepared by a combination of solvent extraction and the SAFE techniques using three matcha powders of different grades (high, medium, and low). Gas chromatography-olfactometry of the headspace samples (GCO-H) and aroma extract dilution analysis (AEDA) applied to the volatile fractions revealed 16 (FD factor ≥1) and 39 (FD factor ≥4 3 ) odor-active peaks, respectively. Among them, 14 and 37 of the odorants, most of which were newly detected in matcha, were identified or tentatively identified by GC-MS and GC-O, respectively. By comparing the perceived odorants of three matcha powders, it was revealed that eight compounds with sweet, green, metallic, and floral notes showed high flavor dilution (FD) factors irrespective of the grades. In addition, some odorants were suggested to influence the characteristic aroma of each grade. Furthermore, trans-4,5-epoxy-(E)-2-decenal, one of the potent odorants of matcha, was revealed to exist as a racemic mixture in matcha. This result suggested that trans-4,5-epoxy-(E)-2-decenal is formed by a nonenzymatic reaction in matcha, different from that in black tea, and that the unique manufacturing process of matcha has a close connection with its formation.

Chemical indices and methods of multivariate statistics as a tool for odor classification.

PubMed

Mahlke, Ingo T; Thiesen, Peter H; Niemeyer, Bernd

2007-04-01

Industrial and agricultural off-gas streams are comprised of numerous volatile compounds, many of which have substantially different odorous properties. State-of-the-art waste-gas treatment includes the characterization of these molecules and is directed at, if possible, either the avoidance of such odorants during processing or the use of existing standardized air purification techniques like bioscrubbing or afterburning, which however, often show low efficiency under ecological and economical regards. Selective odor separation from the off-gas streams could ease many of these disadvantages but is not yet widely applicable. Thus, the aim of this paper is to identify possible model substances in selective odor separation research from 155 volatile molecules mainly originating from livestock facilities, fat refineries, and cocoa and coffee production by knowledge-based methods. All compounds are examined with regard to their structure and information-content using topological and information-theoretical indices. Resulting data are fitted in an observation matrix, and similarities between the substances are computed. Principal component analysis and k-means cluster analysis are conducted showing that clustering of indices data can depict odor information correlating well to molecular composition and molecular shape. Quantitative molecule describtion along with the application of such statistical means therefore provide a good classification tool of malodorant structure properties with no thermodynamic data needed. The approximate look-alike shape of odorous compounds within the clusters suggests a fair choice of possible model molecules.

Elucidation of Thermally Induced Changes in Key Odorants of White Mustard Seeds (Sinapis alba L.) and Rapeseeds (Brassica napus L.) Using Molecular Sensory Science.

PubMed

Ortner, Eva; Granvogl, Michael; Schieberle, Peter

2016-11-02

Heat-processing of Brassica seeds led to the formation of a characteristic pleasant popcorn-like and coffee-like aroma impression compared to the mainly pea-like aroma of the corresponding raw seeds. To analyze this phenomenon on a molecular basis, raw and roasted white mustard seeds and rapeseeds were analyzed using the sensomics approach. Application of comparative aroma extract dilution analysis (cAEDA) and identification experiments to raw and roasted (140 °C, 30 min) mustard seeds revealed 36 odorants (all identified for the first time) and 47 odorants (41 newly identified), respectively. Twenty-seven odorants in raw and 43 odorants in roasted (140 °C, 60 min) rapeseeds were found, which were all described for the first time. Among the set of volatiles, 2-isopropyl-3-methoxypyrazine (earthy, pea-like) and 4-ethenyl-2-methoxyphenol (clove-like, smoky) showed high FD factors in both raw seeds. 4-Hydroxy-2,5-dimethylfuran-3(2H)-one (caramel-like), 2,3-diethyl-5-methylpyrazine (earthy), dimethyl trisulfide (cabbage-like), and 2-acetyl-1-pyrroline (popcorn-like) were present at high flavor dilution (FD) factors in both roasted Brassica seeds. Odorants, differing in cAEDA or showing high FD factors in at least one of the seeds, were quantitated by stable isotope dilution analysis (SIDA), followed by the calculation of odor activity values (OAVs) using odor thresholds determined in refined sunflower oil. Eighteen aroma compounds in raw and 28 in roasted mustard seeds as well as 14 in raw and 25 in roasted rapeseeds revealed OAVs ≥1. All four aroma recombinates, prepared by mixing the odorants showing OAVs ≥1 in their naturally occurring concentrations, showed a very good similarity with the original seeds and, thus, proved the successful characterization of the respective key odorants.

Plant odorants interfere with detection of sex pheromone signals by male Heliothis virescens

PubMed Central

Pregitzer, Pablo; Schubert, Marco; Breer, Heinz; Hansson, Bill S.; Sachse, Silke; Krieger, Jürgen

2012-01-01

In many insects, mate finding relies on female-released sex pheromones, which have to be deciphered by the male olfactory system within an odorous background of plant volatiles present in the environment of a calling female. With respect to pheromone-mediated mate localization, plant odorants may be neutral, favorable, or disturbing. Here we examined the impact of plant odorants on detection and coding of the major sex pheromone component, (Z)-11-hexadecenal (Z11-16:Ald) in the noctuid moth Heliothis virescens. By in vivo imaging the activity in the male antennal lobe (AL), we monitored the interference at the level of olfactory sensory neurons (OSN) to illuminate mixture interactions. The results show that stimulating the male antenna with Z11-16:Ald and distinct plant-related odorants simultaneously suppressed pheromone-evoked activity in the region of the macroglomerular complex (MGC), where Z11-16:Ald-specific OSNs terminate. Based on our previous findings that antennal detection of Z11-16:Ald involves an interplay of the pheromone binding protein (PBP) HvirPBP2 and the pheromone receptor (PR) HR13, we asked if the plant odorants may interfere with any of the elements involved in pheromone detection. Using a competitive fluorescence binding assay, we found that the plant odorants neither bind to HvirPBP2 nor affect the binding of Z11-16:Ald to the protein. However, imaging experiments analyzing a cell line that expressed the receptor HR13 revealed that plant odorants significantly inhibited the Z11-16:Ald-evoked calcium responses. Together the results indicate that plant odorants can interfere with the signaling process of the major sex pheromone component at the receptor level. Consequently, it can be assumed that plant odorants in the environment may reduce the firing activity of pheromone-specific OSNs in H. virescens and thus affect mate localization. PMID:23060749

Olfactory identification in patients with schizophrenia - the influence of β-endorphin and calcitonin gene-related peptide concentrations.

PubMed

Urban-Kowalczyk, M; Śmigielski, J; Strzelecki, D

2017-03-01

The relationship between the olfactory system and emotional processing is an area of growing interest in schizophrenia research. Both the orbitofrontal cortex and amygdala are involved in the processing of olfactory information, and olfactory deficits may be also influenced by endogenous opioids and calcitonin gene-related peptide (CGRP), which is probably involved in dopaminergic transmission. However, the relationship between endorphins and dopaminergic transmission has not been fully explored. Odor identification performance and valence interaction was evaluated among 50 schizophrenic patients and 50 controls. Schizophrenia symptoms were assessed using the Positive and Negative Syndrome Scale (PANSS). All study participants were subjected to the University of Pennsylvania Smell Identification Test (UPSIT), blood β-endorphin (BE) and CGRP measurement. Insignificantly higher BE concentrations were observed in the patient group, while significantly higher UPSIT scores were seen in controls (mean UPSIT 32.48 vs 26.82). The patients demonstrated significantly more identification errors for pleasant (P=0.000) and neutral (P=0.055) odors than for unpleasant odors. Patients with higher BE concentrations made more identification errors concerning pleasant (R s =-0.292; P=0.04) and neutral odors (R s =-0.331; P=0.019). Although the concentration of CGRP was significantly higher in the patient sample (P<0.001), no relationship was observed between concentration and UPSIT performance. A strong negative correlation was observed between PANSS N score and UPSIT total score (R s =-0.646; P=0.000), between PANSS N score and identification by valence for pleasant and neutral odors (UPSIT n/16: R s =-0.450, P=0.001; UPSIT n/15: R s =-0.586, P=0.000), and a weak negative correlation between PANSS N score and identification of unpleasant odors (UPSIT n/9: R s =-0.325, P=0.021). Schizophrenic patients present a unique pattern of smell identification characterized by aberrant hedonic ratings for pleasant odors but not unpleasant ones. Individuals with predominant negative symptoms and higher BE concentrations are most able to identify negative odors. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Alteration of brain activation patterns in nonallergic rhinitis patients using functional magnetic resonance imaging before and after treatment with intranasal azelastine.

PubMed

Bernstein, Jonathan A; Hastings, Lloyd; Boespflug, Erin L; Allendorfer, Jane B; Lamy, Martine; Eliassen, James C

2011-06-01

Although nonallergic rhinitis (NAR) patients tend to be more sensitive to chemical/olfactory stimuli, a suprathreshold olfactory response or the presence of specific olfactory receptor genes do not explain why their symptoms are triggered by such exposures. To investigate differential neurogenic responses to azelastine in NAR patients, using functional magnetic resonance imaging (fMRI) in response to specific olfactory triggers. A longitudinal study design on 12 subjects with a physician diagnosis of NAR previously demonstrated to be clinically responsive to intranasal azelastine (Astelin) was performed. Subjects underwent fMRI during exposure to unpleasant (hickory smoke) and pleasant (vanilla) odorants while off and then on azelastine for 2 weeks. The olfactory fMRI paradigm consisted of a visually triggered sniff every 21 seconds with synchronized delivery of a 4 second pulse of odorant. Each odorant was presented 18 times over 4-6-minute fMRI runs. Continuous fresh air was presented to wash out each odorant after presentation. Nonallergic rhinitis patients exhibited increased blood flow to several regions of the brain in response to both pleasant and unpleasant odorants, specifically in odor-sensitive regions, while off intranasal azelastine. Treatment with intranasal azelastine significantly attenuated blood flow to regions of the brain relevant to either olfactory sensation or sensory processing in response to these odorants compared with fresh air. The general reduction compared with increase in brain activation in NAR patients on versus off azelastine suggests that a possible effect of this medication may be reduction of brain responses to odorants. Copyright © 2011. Published by Elsevier Inc.

Encoding changes in orbitofrontal cortex in reversal-impaired aged rats.

PubMed

Schoenbaum, Geoffrey; Setlow, Barry; Saddoris, Michael P; Gallagher, Michela

2006-03-01

Previous work in rats and primates has shown that normal aging can be associated with a decline in cognitive flexibility mediated by prefrontal circuits. For example, aged rats are impaired in rapid reversal learning, which in young rats depends critically on the orbitofrontal cortex. To assess whether aging-related reversal impairments reflect orbitofrontal dysfunction, we identified aged rats with reversal learning deficits and then recorded single units as these rats, along with unimpaired aged cohorts and young control rats, learned and reversed a series of odor discrimination problems. We found that the flexibility of neural correlates in orbitofrontal cortex was markedly diminished in aged rats characterized as reversal-impaired in initial training. In particular, although many cue-selective neurons in young and aged-unimpaired rats reversed odor preference when the odor-outcome associations were reversed, cue-selective neurons in reversal-impaired aged rats did not. In addition, outcome-expectant neurons in aged-impaired rats failed to become active during cue sampling after learning. These altered features of neural encoding could provide a basis for cognitive inflexibility associated with normal aging.

Key Odorants Regulate Food Attraction in Drosophila melanogaster

PubMed Central

Giang, Thomas; He, Jianzheng; Belaidi, Safaa; Scholz, Henrike

2017-01-01

In insects, the search for food is highly dependent on olfactory sensory input. Here, we investigated whether a single key odorant within an odor blend or the complexity of the odor blend influences the attraction of Drosophila melanogaster to a food source. A key odorant is defined as an odorant that elicits a difference in the behavioral response when two similar complex odor blends are offered. To validate that the observed behavioral responses were elicited by olfactory stimuli, we used olfactory co-receptor Orco mutants. We show that within a food odor blend, ethanol functions as a key odorant. In addition to ethanol other odorants might serve as key odorants at specific concentrations. However, not all odorants are key odorants. The intensity of the odor background influences the attractiveness of the key odorants. Increased complexity is only more attractive in a concentration-dependent range for single compounds in a blend. Orco is necessary to discriminate between two similarly attractive odorants when offered as single odorants and in food odor blends, supporting the importance of single odorant recognition in odor blends. These data strongly indicate that flies use more than one strategy to navigate to a food odor source, depending on the availability of key odorants in the odor blend and the alternative odor offered. PMID:28928642

The pollution characteristics of odor, volatile organochlorinated compounds and polycyclic aromatic hydrocarbons emitted from plastic waste recycling plants.

PubMed

Tsai, Chung-Jung; Chen, Mei-Lien; Chang, Keng-Fu; Chang, Fu-Kuei; Mao, I-Fang

2009-02-01

Plastic waste treatment trends toward recycling in many countries; however, the melting process in the facilities which adopt material recycling method for treating plastic waste may emit toxicants and cause sensory annoyance. The objectives of this study were to analyze the pollution characteristics of the emissions from the plastic waste recycling plants, particularly in harmful volatile organochlorinated compounds, polycyclic aromatic hydrocarbons (PAHs), odor levels and critical odorants. Ten large recycling plants were selected for analysis of odor concentration (OC), volatile organic compounds (VOCs) and PAHs inside and outside the plants using olfactometry, gas chromatography-mass spectrometry and high performance liquid chromatography-fluorescence detector, respectively. The olfactometric results showed that the melting processes used for treating polyethylene/polypropylene (PE/PP) and polyvinyl chloride (PVC) plastic waste significantly produced malodor, and the odor levels at downwind boundaries were 100-229 OC, which all exceeded Taiwan's EPA standard of 50 OC. Toluene, ethylbenzene, 4-methyl-2-pentanone, methyl methacrylate and acrolein accounted for most odors compared to numerous VOCs. Sixteen organochlorinated compounds were measured in the ambient air emitted from the PVC plastic waste recycling plant and total concentrations were 245-553 microg m(-3); most were vinyl chloride, chloroform and trichloroethylene. Concentrations of PAHs inside the PE/PP plant were 8.97-252.16 ng m(-3), in which the maximum level were 20-fold higher than the levels detected from boundaries. Most of these recycling plants simply used filter to treat the melting fumes, and this could not efficiently eliminate the gaseous compounds and malodor. Improved exhaust air pollution control were strongly recommended in these industries.

Bioelectronic Nose Using Odorant Binding Protein-Derived Peptide and Carbon Nanotube Field-Effect Transistor for the Assessment of Salmonella Contamination in Food.

PubMed

Son, Manki; Kim, Daesan; Kang, Jinkyung; Lim, Jong Hyun; Lee, Seung Hwan; Ko, Hwi Jin; Hong, Seunghun; Park, Tai Hyun

2016-12-06

Salmonella infection is the one of the major causes of food borne illnesses including fever, abdominal pain, diarrhea, and nausea. Thus, early detection of Salmonella contamination is important for our healthy life. Conventional detection methods for the food contamination have limitations in sensitivity and rapidity; thus, the early detection has been difficult. Herein, we developed a bioelectronic nose using a carbon nanotube (CNT) field-effect transistor (FET) functionalized with Drosophila odorant binding protein (OBP)-derived peptide for easy and rapid detection of Salmonella contamination in ham. 3-Methyl-1-butanol is known as a specific volatile organic compound, generated from the ham contaminated with Salmonella. We designed and synthesized the peptide based on the sequence of the Drosophila OBP, LUSH, which specifically binds to alcohols. The C-terminus of the synthetic peptide was modified with three phenylalanine residues and directly immobilized onto CNT channels using the π-π interaction. The p-type properties of FET were clearly maintained after the functionalization using the peptide. The biosensor detected 1 fM of 3-methyl-1-butanol with high selectivity and successfully assessed Salmonella contamination in ham. These results indicate that the bioelectronic nose can be used for the rapid detection of Salmonella contamination in food.

Rapid Stress System Drives Chemical Transfer of Fear from Sender to Receiver

PubMed Central

de Groot, Jasper H. B.; Smeets, Monique A. M.; Semin, Gün R.

2015-01-01

Humans can register another person’s fear not only with their eyes and ears, but also with their nose. Previous research has demonstrated that exposure to body odors from fearful individuals elicited implicit fear in others. The odor of fearful individuals appears to have a distinctive signature that can be produced relatively rapidly, driven by a physiological mechanism that has remained unexplored in earlier research. The apocrine sweat glands in the armpit that are responsible for chemosignal production contain receptors for adrenalin. We therefore expected that the release of adrenalin through activation of the rapid stress response system (i.e., the sympathetic-adrenal medullary system) is what drives the release of fear sweat, as opposed to activation of the slower stress response system (i.e., hypothalamus-pituitary-adrenal axis). To test this assumption, sweat was sampled while eight participants prepared for a speech. Participants had higher heart rates and produced more armpit sweat in the fast stress condition, compared to baseline and the slow stress condition. Importantly, exposure to sweat from participants in the fast stress condition induced in receivers (N = 31) a simulacrum of the state of the sender, evidenced by the emergence of a fearful facial expression (facial electromyography) and vigilant behavior (i.e., faster classification of emotional facial expressions). PMID:25723720

Evolution of olfactory receptors.

PubMed

Hoover, Kara C

2013-01-01

Olfactory receptors are a specialized set of receptor cells responsible for the detection of odors. These cells are G protein-coupled receptors and expressed in the cell membranes of olfactory sensory neurons. Once a cell is activated by a ligand, it initiates a signal transduction cascade that produces a nerve impulse to the brain where odor perception is processed. Vertebrate olfactory evolution is characterized by birth-and-death events, a special case of the stochastic continuous time Markov process. Vertebrate fish have three general types of receptor cells (two dedicated to pheromones). Terrestrial animals have different epithelial biology due to the specialized adaptation to detecting airborne odors. Two general classes of olfactory receptor gene reflect the vertebrate marine heritage (Class I) and the derived amphibian, reptile, and mammal terrestrial heritage (Class II). While we know much about olfactory receptor cells, there are still areas where our knowledge is insufficient, such as intra-individual diversity throughout the life time, epigenetic processes acting on olfactory receptors, and association of ligands to specific cells.

Nanocellulose-Zeolite Composite Films for Odor Elimination.

PubMed

Keshavarzi, Neda; Mashayekhy Rad, Farshid; Mace, Amber; Ansari, Farhan; Akhtar, Farid; Nilsson, Ulrika; Berglund, Lars; Bergström, Lennart

2015-07-08

Free standing and strong odor-removing composite films of cellulose nanofibrils (CNF) with a high content of nanoporous zeolite adsorbents have been colloidally processed. Thermogravimetric desorption analysis (TGA) and infrared spectroscopy combined with computational simulations showed that commercially available silicalite-1 and ZSM-5 have a high affinity and uptake of volatile odors like ethanethiol and propanethiol, also in the presence of water. The simulations showed that propanethiol has a higher affinity, up to 16%, to the two zeolites compared with ethanethiol. Highly flexible and strong free-standing zeolite-CNF films with an adsorbent loading of 89 w/w% have been produced by Ca-induced gelation and vacuum filtration. The CNF-network controls the strength of the composite films and 100 μm thick zeolite-CNF films with a CNF content of less than 10 vol % displayed a tensile strength approaching 10 MPa. Headspace solid phase microextraction (SPME) coupled to gas chromatography-mass spectroscopy (GC/MS) analysis showed that the CNF-zeolite films can eliminate the volatile thiol-based odors to concentrations below the detection ability of the human olfactory system. Odor removing zeolite-cellulose nanofibril films could enable improved transport and storage of fruits and vegetables rich in odors, for example, onion and the tasty but foul-smelling South-East Asian Durian fruit.

Altered olfactory processing and increased insula activity in patients with obsessive-compulsive disorder: an fMRI study

PubMed Central

Berlin, Heather A.; Stern, Emily R.; Ng, Johnny; Zhang, Sam; Rosenthal, David; Turetzky, Rachel; Tang, Cheuk; Goodman, Wayne

2017-01-01

Obsessive-compulsive disorder (OCD) patients show increased insula activation to disgust-inducing images compared to healthy controls (HC). We explored whether this disgust reactivity was also present in the olfactory domain by conducting the first fMRI study of olfaction in OCD. Neural activation in response to pleasant and unpleasant odors (vs. unscented air) was investigated in 15 OCD and 15 HC participants using fMRI. OCD participants (vs. HC) had increased left anterior insula activation to unpleasant odors (vs. unscented air), which positively correlated with their disgust sensitivity and ratings of the unpleasantness and intensity of those odors. OCD participants (vs. HC) showed increased activation of caudate nucleus and left anterior and posterior insula to pleasant odors (vs. unscented air), which positively correlated with their OCD symptom severity, trait anxiety, frequency of feeling disgust, and odor intensity ratings. OCD participants had increased anterior insula activation to both pleasant and unpleasant odors, which correlated with their OCD symptoms, anxiety, disgust sensitivity, and frequency of feeling disgust. OCD patients might have a negative cognitive bias and experience all stimuli, regardless of valence, as being more unpleasant than healthy people. These findings further elucidate the neural underpinnings of OCD and may contribute to more effective treatments. PMID:28208068

Collective odor source estimation and search in time-variant airflow environments using mobile robots.

PubMed

Meng, Qing-Hao; Yang, Wei-Xing; Wang, Yang; Zeng, Ming

2011-01-01

This paper addresses the collective odor source localization (OSL) problem in a time-varying airflow environment using mobile robots. A novel OSL methodology which combines odor-source probability estimation and multiple robots' search is proposed. The estimation phase consists of two steps: firstly, the separate probability-distribution map of odor source is estimated via Bayesian rules and fuzzy inference based on a single robot's detection events; secondly, the separate maps estimated by different robots at different times are fused into a combined map by way of distance based superposition. The multi-robot search behaviors are coordinated via a particle swarm optimization algorithm, where the estimated odor-source probability distribution is used to express the fitness functions. In the process of OSL, the estimation phase provides the prior knowledge for the searching while the searching verifies the estimation results, and both phases are implemented iteratively. The results of simulations for large-scale advection-diffusion plume environments and experiments using real robots in an indoor airflow environment validate the feasibility and robustness of the proposed OSL method.

Collective Odor Source Estimation and Search in Time-Variant Airflow Environments Using Mobile Robots

PubMed Central

Meng, Qing-Hao; Yang, Wei-Xing; Wang, Yang; Zeng, Ming

2011-01-01

This paper addresses the collective odor source localization (OSL) problem in a time-varying airflow environment using mobile robots. A novel OSL methodology which combines odor-source probability estimation and multiple robots’ search is proposed. The estimation phase consists of two steps: firstly, the separate probability-distribution map of odor source is estimated via Bayesian rules and fuzzy inference based on a single robot’s detection events; secondly, the separate maps estimated by different robots at different times are fused into a combined map by way of distance based superposition. The multi-robot search behaviors are coordinated via a particle swarm optimization algorithm, where the estimated odor-source probability distribution is used to express the fitness functions. In the process of OSL, the estimation phase provides the prior knowledge for the searching while the searching verifies the estimation results, and both phases are implemented iteratively. The results of simulations for large-scale advection–diffusion plume environments and experiments using real robots in an indoor airflow environment validate the feasibility and robustness of the proposed OSL method. PMID:22346650

The Putative Chemosignal Androstadienone Makes Women More Generous.

PubMed

Perrotta, Valentina; Graffeo, Michele; Bonini, Nicolao; Gottfried, Jay A

2016-06-01

Putative human chemosignals have been shown to influence mood states and emotional processing, but the connection between these effects and higher-order cognitive processing is not well established. This study utilized an economic game (Dictator Game) to test whether androstadienone (AND), an odorous compound derived from testosterone, impacts on altruistic behavior. We predicted that the female participants would act more generously in the AND condition, exhibiting a significant interaction effect between gender and AND on Dictator Game contributions. We also expected that the presence of AND should increase the positive mood of the female participants, compared to a control odor condition and also compared to the mood of the male participants. The results confirm our hypotheses: for women the subliminal perception of AND led to larger monetary donations, compared to a control odor, and also increased positive mood. These effects were absent or significantly weaker in men. Our findings highlight the capacity of human putative chemosignals to influence emotions and higher cognitive processes - in particular the processes used in the context of economic decisions - in a gender-specific way.

Collection and identification of human remains volatiles by non-contact, dynamic airflow sampling and SPME-GC/MS using various sorbent materials.

PubMed

DeGreeff, Lauryn E; Furton, Kenneth G

2011-09-01

Human remains detection canines are used in locating deceased humans in diverse scenarios and environments based on odor produced during the decay process of the human body. It has been established that human remains detection canines are capable of locating human remains specifically, as opposed to living humans or animal remains, thus suggesting a difference in odor between the different sources. This work explores the collection and determination of such odors using a dynamic headspace concentration device. The airflow rate and three sorbent materials-Dukal cotton gauze, Johnson & Johnson cotton-blend gauze, and polyester material-used for odor collection were evaluated using standard compounds. It was determined that higher airflow rates and openly woven material, e.g., Dukal cotton gauze, yielded significantly less total volatile compounds due to compound breakthrough through the sorbent material. Collection from polymer- and cellulose-based materials demonstrated that the molecular backbone of the material is a factor in compound collection as well. Volatiles, including cyclic and straight-chain hydrocarbons, organic acids, sulfides, aldehydes, ketones, and alcohols, were collected from a population of 27 deceased bodies from two collection locations. The common compounds between the subjects were compared and the odor profiles were determined. These odor profiles were compared with those of animal remains and living human subjects collected in the same manner. Principal component analysis showed that the odor profiles of the three sample types were distinct.

Side-Specificity of Olfactory Learning in the Honeybee: Generalization between Odors and Sides

PubMed Central

Sandoz, Jean-Christophe; Menzel, Randolf

2001-01-01

Honeybees (Apis mellifera) can be trained to associate an odor stimulus with a sucrose reward. The neural structures involved in the detection and integration of olfactory stimuli are represented bilaterally in the brain. Little is known about the respective roles of the two sides of the brain in olfactory learning. Does each side learn independently of the other, or do they communicate, and if so, to what extent and at what level of neural integration? We addressed these questions using the proboscis extension response (PER) conditioning paradigm applied in a preparation that allows the separation of the two input sides during olfactory stimulations. Bees conditioned to two odorants A and B, one being learned on each side (A+/B+ training), showed in extinction tests rather unspecific responses: They responded to both odorants on both sides. This could be attributable to either a transfer of the learned information between sides, or to a generalization between odorants on each side. By subjecting bees to conditioning on one side only (A+/0 training), we found that the learned information is indeed transferred between sides. However, when bees were trained explicitly to give opposite values to the two odorants on the two sides (A+B−/B+A− training), they showed clear side-specific response patterns to these odorants. These results are used in the elaboration of a functional model of laterality of olfactory learning and memory processing in the honeybee brain. PMID:11584076

A novel Arometic compound acts synergistically with a naturally occurring monoterpene to elicit strong behavioral responses in Asian citrus psyllid

USDA-ARS?s Scientific Manuscript database

Inscent, Inc. has developed methodologies for rapidly screening potential ligands of chemosensory proteins (CSPs) isolated from the antennae of target insects. These novel ligands, referred to as Arometics, mimic naturally-occurring odorants and may function as super-stimuli because of their strong ...

Investigation of Volatiles Emitted from Freshly Cut Onions (Allium cepa L.) by Real Time Proton-Transfer Reaction-Mass Spectrometry (PTR-MS)

PubMed Central

Løkke, Mette Marie; Edelenbos, Merete; Larsen, Erik; Feilberg, Anders

2012-01-01

Volatile organic compounds (VOCs) in cut onions (Allium cepa L.) were continuously measured by PTR-MS during the first 120 min after cutting. The headspace composition changed rapidly due to the very reactive volatile sulfurous compounds emitted from onion tissue after cell disruption. Mass spectral signals corresponding to propanethial S-oxide (the lachrymatory factor) and breakdown products of this compound dominated 0–10 min after cutting. Subsequently, propanethiol and dipropyl disulfide predominantly appeared, together with traces of thiosulfinates. The concentrations of these compounds reached a maximum at 60 min after cutting. Propanethiol was present in highest concentrations and had an odor activity value 20 times higher than dipropyl disulfide. Thus, propanethiol is suggested to be the main source of the characteristic onion odor. Monitoring the rapid changes of VOCs in the headspace of cut onion necessitates a high time resolution, and PTR-MS is demonstrated to be a very suitable method for monitoring the headspace of freshly cut onions directly after cutting without extraction or pre-concentration. PMID:23443367

Cognitive Load Alters Neuronal Processing of Food Odors.

PubMed

Hoffmann-Hensel, Sonja Maria; Sijben, Rik; Rodriguez-Raecke, Rea; Freiherr, Jessica

2017-10-31

Obesity is a major health concern in modern societies. Although decreased physical activity and enhanced intake of high-caloric foods are important risk factors for developing obesity, human behavior during eating also plays a role. Previous studies have shown that distraction while eating increases food intake and leads to impaired processing of food stimuli. As olfaction is the most important sense involved in flavor perception, we used functional magnetic resonance imaging techniques to investigate the influence of cognitive memory load on olfactory perception and processing. Low- and high-caloric food odors were presented in combination with either low or high cognitive loads utilizing a memory task. The efficacy of the memory task was verified by a decrease in participant recall accuracy and an increase in skin conductance response during high cognitive load. Our behavioral data reveal a diminished perceived intensity for low- but not high-caloric food odors during high cognitive load. For low-caloric food odors, bilateral orbitofrontal (OFC) and piriform cortices (pirC) showed significantly lower activity during high compared with low cognitive load. For high-caloric food odors, a similar effect was established in pirC, but not in OFC. Insula activity correlates with higher intensity ratings found during the low cognitive load condition. We conclude lower activity in pirC and OFC to be responsible for diminished intensity perception, comparable to results in olfactory impaired patients and elderly. Further studies should investigate the influence of olfactory/gustatory intensities on food choices under distraction with special regards to low-caloric food. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

[Elimination of volatile compounds of leaf tobacco from air emissions using biofiltration].

PubMed

Zagustina, N A; Misharina, T A; Vepritskiĭ, A A; Zhukov, V G; Ruzhitskiĭ, A O; Terenina, M B; Krikunova, N I; Kulikova, A K; Popov, V O

2012-01-01

The composition of the volatile organic compounds (VOCs) of various leaf tobacco brands and their blends has been studied. The differences in the content of nicotine, solanone, tetramethyl hexadecenol, megastigmatrienones, and other compounds, determining the specific tobacco smell, have been revealed. A microbial consortium, which is able to deodorize simulated tobacco emissions and decompose nicotine, has been formed by long-term adaptation to the VOCs of tobacco leaves in a laboratory reactor, functioning as a trickle-bed biofilter. Such a biofilter eliminates 90% of the basic toxic compound (nicotine) and odor-active compounds; the filtration efficiency does not change for tobacco brands with different VOC concentrations or in the presence of foreign substances. The main strains, isolated from the formed consortium and participating in the nicotine decomposition process, belong to the genera Pseudomonas, Bacillus, and Rhodococcus. An examination of the biofilter trickling fluid has shown full decomposition of nicotine and odor-active VOCs. The compounds, revealed in the trickling fluid, did not have any odor and were nontoxic. The obtained results make it possible to conduct scaling of the biofiltration process to eliminate odor from air emissions in the tobacco industry.

[How we smell and what it means to us: basic principles of the sense of smell].

PubMed

Manzini, I; Frasnelli, J; Croy, I

2014-12-01

The origins of the sense of smell lie in the perception of environmental molecules and go back to unicellular organisms such as bacteria. Odors transmit a multitude of information about the chemical composition of our environment. The sense of smell helps people and animals with orientation in space, warns of potential threats, influences the choice of sexual partners, regulates food intake and influences feelings and social behavior in general. The perception of odors begins in sensory neurons residing in the olfactory epithelium that express G protein-coupled receptors, the so-called olfactory receptors. The binding of odor molecules to olfactory receptors initiates a signal transduction cascade that converts olfactory stimuli into electrical signals. These signals are then transmitted to the olfactory bulb, the first relay center in the olfactory pathway, via the axons of the sensory neurons. The olfactory information is processed in the bulb and then transferred to higher olfactory centers via axons of mitral cells, the bulbar projection neurons. This review describes the mechanisms involved in peripheral detection of odorants, outlines the further processing of olfactory information in higher olfactory centers and finally gives an overview of the overall significance of the ability to smell.

Increasing cell-device adherence using cultured insect cells for receptor-based biosensors

NASA Astrophysics Data System (ADS)

Terutsuki, Daigo; Mitsuno, Hidefumi; Sakurai, Takeshi; Okamoto, Yuki; Tixier-Mita, Agnès; Toshiyoshi, Hiroshi; Mita, Yoshio; Kanzaki, Ryohei

2018-03-01

Field-effect transistor (FET)-based biosensors have a wide range of applications, and a bio-FET odorant sensor, based on insect (Sf21) cells expressing insect odorant receptors (ORs) with sensitivity and selectivity, has emerged. To fully realize the practical application of bio-FET odorant sensors, knowledge of the cell-device interface for efficient signal transfer, and a reliable and low-cost measurement system using the commercial complementary metal-oxide semiconductor (CMOS) foundry process, will be indispensable. However, the interfaces between Sf21 cells and sensor devices are largely unknown, and electrode materials used in the commercial CMOS foundry process are generally limited to aluminium, which is reportedly toxic to cells. In this study, we investigated Sf21 cell-device interfaces by developing cross-sectional specimens. Calcium imaging of Sf21 cells expressing insect ORs was used to verify the functions of Sf21 cells as odorant sensor elements on the electrode materials. We found that the cell-device interface was approximately 10 nm wide on average, suggesting that the adhesion mechanism of Sf21 cells may differ from that of other cells. These results will help to construct accurate signal detection from expressed insect ORs using FETs.

Increasing cell–device adherence using cultured insect cells for receptor-based biosensors

PubMed Central

Mitsuno, Hidefumi; Sakurai, Takeshi; Okamoto, Yuki; Tixier-Mita, Agnès; Toshiyoshi, Hiroshi; Mita, Yoshio; Kanzaki, Ryohei

2018-01-01

Field-effect transistor (FET)-based biosensors have a wide range of applications, and a bio-FET odorant sensor, based on insect (Sf21) cells expressing insect odorant receptors (ORs) with sensitivity and selectivity, has emerged. To fully realize the practical application of bio-FET odorant sensors, knowledge of the cell–device interface for efficient signal transfer, and a reliable and low-cost measurement system using the commercial complementary metal-oxide semiconductor (CMOS) foundry process, will be indispensable. However, the interfaces between Sf21 cells and sensor devices are largely unknown, and electrode materials used in the commercial CMOS foundry process are generally limited to aluminium, which is reportedly toxic to cells. In this study, we investigated Sf21 cell–device interfaces by developing cross-sectional specimens. Calcium imaging of Sf21 cells expressing insect ORs was used to verify the functions of Sf21 cells as odorant sensor elements on the electrode materials. We found that the cell–device interface was approximately 10 nm wide on average, suggesting that the adhesion mechanism of Sf21 cells may differ from that of other cells. These results will help to construct accurate signal detection from expressed insect ORs using FETs. PMID:29657822

Data-driven inference of network connectivity for modeling the dynamics of neural codes in the insect antennal lobe

PubMed Central

Shlizerman, Eli; Riffell, Jeffrey A.; Kutz, J. Nathan

2014-01-01

The antennal lobe (AL), olfactory processing center in insects, is able to process stimuli into distinct neural activity patterns, called olfactory neural codes. To model their dynamics we perform multichannel recordings from the projection neurons in the AL driven by different odorants. We then derive a dynamic neuronal network from the electrophysiological data. The network consists of lateral-inhibitory neurons and excitatory neurons (modeled as firing-rate units), and is capable of producing unique olfactory neural codes for the tested odorants. To construct the network, we (1) design a projection, an odor space, for the neural recording from the AL, which discriminates between distinct odorants trajectories (2) characterize scent recognition, i.e., decision-making based on olfactory signals and (3) infer the wiring of the neural circuit, the connectome of the AL. We show that the constructed model is consistent with biological observations, such as contrast enhancement and robustness to noise. The study suggests a data-driven approach to answer a key biological question in identifying how lateral inhibitory neurons can be wired to excitatory neurons to permit robust activity patterns. PMID:25165442

Microoxidation in wine production.

PubMed

Kilmartin, Paul A

2010-01-01

Microoxygenation (MOX) is now widely applied for the maturation of red wines as an alternative to barrel aging. The proposed improvements in wine quality arising from MOX include color stabilization, removal of unwanted off-odors, and improvements in wine mouthfeel. In this review, an outline is provided of oxygenation systems, particularly microbullage and polymer membrane delivery, and of the current understanding of wine oxidation processes. A summary of the results from published studies into red wine MOX is then provided, beginning with observations on O(2) and acetaldehyde accumulation, and the moderating effect of added sulfur dioxide. Effects upon red wine color, particularly the more rapid formation of polymeric pigments and higher color retention, have been consistently demonstrated in MOX studies, along with further effects on specific polyphenol compounds. A few reports have recently examined the effect of MOX on red wine aromas, but these have yet to identify compounds that consistently change in a manner that would explain sensory observations regarding a lowering of herbaceous and reductive odors. Likewise, tannin analyses have been undertaken in several studies, but explanations of the decline in wine astringency remain to be developed. The accelerated growth of unwanted microorganisms has also been examined in a limited number of studies, but no major problems have been identified in this area. Copyright © 2010 Elsevier Inc. All rights reserved.

Neurophysiological Response to Olfactory Stimuli in Combat Veterans With Posttraumatic Stress Disorder.

PubMed

Bedwell, Jeffrey S; Bohil, Corey J; Neider, Mark B; Gramlich, Michael A; Neer, Sandra M; OʼDonnell, John P; Beidel, Deborah C

2018-06-01

There is a need for a better understanding of underlying pathology in posttraumatic stress disorder (PTSD) to develop more effective treatments. The late positive potential (LPP) amplitude from electroencephalogram has been used to assess individual differences in emotional reactivity. There is evidence that olfaction is particularly important in emotional processing in PTSD. The current study examined LPP amplitudes in response to olfactory stimuli in 24 combat veterans with PTSD and 24 nonmilitary/non-PTSD controls. An olfactometer delivered three negatively valenced odorants, with 12 trials of each delivered in a random order. The groups did not differ in LPP amplitude across odorants. However, within the PTSD group, higher Clinician-Administered PTSD Scale scores related to an increased LPP amplitude after diesel fuel and rotten egg, but not n_butanol, odorants. Results provide specific targets and theory for further research into clinical applications such as selection of idiographic odorants for use in virtual-reality exposure therapy.

Aroma Characterization and Safety Assessment of a Beverage Fermented by Trametes versicolor.

PubMed

Zhang, Yanyan; Fraatz, Marco Alexander; Müller, Julia; Schmitz, Hans-Joachim; Birk, Florian; Schrenk, Dieter; Zorn, Holger

2015-08-12

A cereal-based beverage was developed by fermentation of wort with the basidiomycete Trametes versicolor. The beverage possessed a fruity, fresh, and slightly floral aroma. The volatiles of the beverage were isolated by liquid-liquid extraction (LLE) and additionally by headspace solid phase microextraction (HS-SPME). The aroma compounds were analyzed by a gas chromatography system equipped with a tandem mass spectrometer and an olfactory detection port (GC-MS/MS-O) followed by aroma (extract) dilution analysis. Thirty-four different odor impressions were perceived, and 27 corresponding compounds were identified. Fifteen key odorants with flavor dilution (FD) factors ranging from 8 to 128 were quantitated, and their respective odor activity values (OAVs) were calculated. Six key odorants were synthesized de novo by T. versicolor. Furthermore, quantitative changes during the fermentation process were analyzed. To prepare for the market introduction of the beverage, a comprehensive safety assessment was performed.

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

PubMed

Kaplan, Bernhard A; Lansner, Anders

2014-01-01

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

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

PubMed Central

Kaplan, Bernhard A.; Lansner, Anders

2014-01-01

Olfactory sensory information passes through several processing stages before an odor percept emerges. The question how the olfactory system learns to create odor representations linking those different levels and how it learns to connect and discriminate between them is largely unresolved. We present a large-scale network model with single and multi-compartmental Hodgkin–Huxley type model neurons representing olfactory receptor neurons (ORNs) in the epithelium, periglomerular cells, mitral/tufted cells and granule cells in the olfactory bulb (OB), and three types of cortical cells in the piriform cortex (PC). Odor patterns are calculated based on affinities between ORNs and odor stimuli derived from physico-chemical descriptors of behaviorally relevant real-world odorants. The properties of ORNs were tuned to show saturated response curves with increasing concentration as seen in experiments. On the level of the OB we explored the possibility of using a fuzzy concentration interval code, which was implemented through dendro-dendritic inhibition leading to winner-take-all like dynamics between mitral/tufted cells belonging to the same glomerulus. The connectivity from mitral/tufted cells to PC neurons was self-organized from a mutual information measure and by using a competitive Hebbian–Bayesian learning algorithm based on the response patterns of mitral/tufted cells to different odors yielding a distributed feed-forward projection to the PC. The PC was implemented as a modular attractor network with a recurrent connectivity that was likewise organized through Hebbian–Bayesian learning. We demonstrate the functionality of the model in a one-sniff-learning and recognition task on a set of 50 odorants. Furthermore, we study its robustness against noise on the receptor level and its ability to perform concentration invariant odor recognition. Moreover, we investigate the pattern completion capabilities of the system and rivalry dynamics for odor mixtures. PMID:24570657

Chemosensory danger detection in the human brain: Body odor communicating aggression modulates limbic system activation.

PubMed

Mutic, Smiljana; Brünner, Yvonne F; Rodriguez-Raecke, Rea; Wiesmann, Martin; Freiherr, Jessica

2017-05-01

Although the sense of smell is involved in numerous survival functions, the processing of body odor emitted by dangerous individuals is far from understood. The aim of the study was to explore how human fight chemosignals communicating aggression can alter brain activation related to an attentional bias and danger detection. While the anterior cingulate cortex (ACC) was seen involved in processing threat-related emotional information, danger detection and error evaluation, it still remains unknown whether human chemosignals communicating aggression can potentially modulate this activation. In the fMRI experiment, healthy male and female normosmic odor recipients (n=18) completed a higher-order processing task (emotional Stroop task with the word categories anger, anxiety, happiness and neutral) while exposed to aggression and exercise chemosignals (collected from a different group of healthy male donors; n=16). Our results provide first evidence that aggression chemosignals induce a time-sensitive attentional bias in chemosensory danger detection and modulate limbic system activation. During exposure to aggression chemosignals compared to exercise chemosignals, functional imaging data indicates an enhancement of thalamus, hypothalamus and insula activation (p<.05, FWE-corrected). Together with the thalamus, the ACC was seen activated in response to threat-related words (p<.001). Chemosensory priming and habituation to body odor signals are discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Different Ways to Apply a Measurement Instrument of E-Nose Type to Evaluate Ambient Air Quality with Respect to Odour Nuisance in a Vicinity of Municipal Processing Plants

PubMed Central

Szulczyński, Bartosz; Wasilewski, Tomasz; Wojnowski, Wojciech; Majchrzak, Tomasz; Dymerski, Tomasz; Namieśnik, Jacek; Gębicki, Jacek

2017-01-01

This review paper presents different ways to apply a measurement instrument of e-nose type to evaluate ambient air with respect to detection of the odorants characterized by unpleasant odour in a vicinity of municipal processing plants. An emphasis was put on the following applications of the electronic nose instruments: monitoring networks, remote controlled robots and drones as well as portable devices. Moreover, this paper presents commercially available sensors utilized in the electronic noses and characterized by the limit of quantification below 1 ppm v/v, which is close to the odour threshold of some odorants. Additionally, information about bioelectronic noses being a possible alternative to electronic noses and their principle of operation and application potential in the field of air evaluation with respect to detection of the odorants characterized by unpleasant odour was provided. PMID:29156597

Different Ways to Apply a Measurement Instrument of E-Nose Type to Evaluate Ambient Air Quality with Respect to Odour Nuisance in a Vicinity of Municipal Processing Plants.

PubMed

Szulczyński, Bartosz; Wasilewski, Tomasz; Wojnowski, Wojciech; Majchrzak, Tomasz; Dymerski, Tomasz; Namieśnik, Jacek; Gębicki, Jacek

2017-11-19

This review paper presents different ways to apply a measurement instrument of e-nose type to evaluate ambient air with respect to detection of the odorants characterized by unpleasant odour in a vicinity of municipal processing plants. An emphasis was put on the following applications of the electronic nose instruments: monitoring networks, remote controlled robots and drones as well as portable devices. Moreover, this paper presents commercially available sensors utilized in the electronic noses and characterized by the limit of quantification below 1 ppm v / v , which is close to the odour threshold of some odorants. Additionally, information about bioelectronic noses being a possible alternative to electronic noses and their principle of operation and application potential in the field of air evaluation with respect to detection of the odorants characterized by unpleasant odour was provided.

Research on odor interaction between aldehyde compounds via a partial differential equation (PDE) model.

PubMed

Yan, Luchun; Liu, Jiemin; Qu, Chen; Gu, Xingye; Zhao, Xia

2015-01-28

In order to explore the odor interaction of binary odor mixtures, a series of odor intensity evaluation tests were performed using both individual components and binary mixtures of aldehydes. Based on the linear relation between the logarithm of odor activity value and odor intensity of individual substances, the relationship between concentrations of individual constituents and their joint odor intensity was investigated by employing a partial differential equation (PDE) model. The obtained results showed that the binary odor interaction was mainly influenced by the mixing ratio of two constituents, but not the concentration level of an odor sample. Besides, an extended PDE model was also proposed on the basis of the above experiments. Through a series of odor intensity matching tests for several different binary odor mixtures, the extended PDE model was proved effective at odor intensity prediction. Furthermore, odorants of the same chemical group and similar odor type exhibited similar characteristics in the binary odor interaction. The overall results suggested that the PDE model is a more interpretable way of demonstrating the odor interactions of binary odor mixtures.

Simple circular odor chart for characterization of trace amounts of odorants discharged from thirteen odor sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoshika, Y.; Nihei, Y.; Muto, G.

1981-04-01

A simple circular odor chart is proposed for the explanation of the relationship between sensory responses (to odor quality and intensity) to odors and chemical analysis data of the odorants responsible for each odor discharged from thirteen odor sources. The odorants were classified into eight odorant groups and were analyzed by a systematic gas chromatographic (GC) technique. The characterization of the trace amounts of the odorants was carried out by using the values of a new proposed unit (pOU) based on the ratio of detected concentration to recognition threshold value. The calculated pOU values of the eight groups were plottedmore » in circular charts. It was found that the shape and size of each circular odor chart represent the quality and the intensity of each odor.« less

Odors: appetizing or satiating? Development of appetite during odor exposure over time.

PubMed

Ramaekers, M G; Boesveldt, S; Lakemond, C M M; van Boekel, M A J S; Luning, P A

2014-05-01

Exposure to palatable food odors influences appetite responses, either promoting or inhibiting food intake. Possibly, food odors are appetizing after a short exposure (of circa 1-3 min), but become satiating over time (circa 10-20 min). To investigate the effect of odor exposure on general appetite and sensory-specific appetite (SSA) over time. In a cross-over study, 21 unrestrained women (age: 18-45 years; BMI: 18.5-25 kg m(-2)) were exposed for 20 min to eight different odor types: five food odors, two nonfood odors and no-odor. All odors were distributed in a test room at suprathreshold levels. General appetite, SSA and salivation were measured over time. All food odors significantly increased general appetite and SSA, compared with the no-odor condition. The nonfood odors decreased general appetite. All effects did not change over time during odor exposure. Savory odors increased the appetite for savory foods, but decreased appetite for sweet foods, and vice versa after exposure to sweet odors. Neither food odors nor nonfood odors affected salivation. Palatable food odors were appetizing during and after odor exposure and did not become satiating over a 20-min period. Food odors had a large impact on SSA and a small impact on general appetite. Moreover, exposure to food odors increased the appetite for congruent foods, but decreased the appetite for incongruent foods. It may be hypothesized that, once the body is prepared for intake of a certain food with a particular macronutrient composition, it is unfavorable to consume foods that are very different from the cued food.

Analysis of public perception about impaired odor in center fishery processing industry Tegalsari Tegal city

NASA Astrophysics Data System (ADS)

Wibowo, Tri Setyo; Purwanto, P.; Yulianto, Bambang

2017-03-01

The Coastal Fishing Port (CFP) Tegalsari is one of the largest center of the fishery industries in Central Java Indonesia. In addition to producing fish-based products such as fish fillets, salted fish and fish meal are distributed to most major cities in Indonesia, but also generate waste and wastewater which potentially disrupt the environment. The purpose of this study describe the perception of the public about the negative impact of the activities in center fishery processing industry. The research method uses qualitative research design with the population living around the center of the fishing industry, with samples taken by purposive sampling numbered 30 people and 3 location sample to know concentration of ammoniac and hydrogen Sulfide. Data research in 2016 was processed using statistical methods. The results of research showed very significant, 80% of respondents who said the fishing activities causing nuisance odor. The remaining 20% stated that the odor nuisance almost imperceptibly. The nuisance of odor are perceived by 53% of respondents for a full day. There are 70% of respondents living around the center of the fishing industry who lived more than seven years, and the remaining 30% of respondents who lived less than 7 years. Conclusion respondent who live more than seven years and said there was no odor nuisance around 57%, are more than 50% of the respondents. The odor of the most influential parameter on the fishing industry is an element of ammoniac (NH3) instead of Hydrogen Sulfide (H2S), because the value at these three locations for Hydrogen Sulfide measurement results show the same number that is equal to 0.001 g/m3. While ammoniac levels at most locations smelled according to perceptions of examiners showed the highest scores, while the zone that did not feel the smell indicates a low value, the test results showed a clear level of distinction. So the need to manage the environment at the center of the fishing industry with a approach of clean technology program.

Temporally diverse firing patterns in olfactory receptor neurons underlie spatiotemporal neural codes for odors

PubMed Central

Raman, Baranidharan; Joseph, Joby; Tang, Jeff; Stopfer, Mark

2010-01-01

Odorants are represented as spatiotemporal patterns of spikes in neurons of the antennal lobe (AL, insects) and olfactory bulb (OB, vertebrates). These response patterns have been thought to arise primarily from interactions within the AL/OB, an idea supported, in part, by the assumption that olfactory receptor neurons (ORNs) respond to odorants with simple firing patterns. However, activating the AL directly with simple pulses of current evoked responses in AL neurons that were much less diverse, complex, and enduring than responses elicited by odorants. Similarly, models of the AL driven by simplistic inputs generated relatively simple output. How then are dynamic neural codes for odors generated? Consistent with recent results from several other species, our recordings from locust ORNs showed a great diversity of temporal structure. Further, we found that, viewed as a population, many response features of ORNs were remarkably similar to those observed within the AL. Using a set of computational models constrained by our electrophysiological recordings, we found that the temporal heterogeneity of responses of ORNs critically underlies the generation of spatiotemporal odor codes in the AL. A test then performed in vivo confirmed that, given temporally homogeneous input, the AL cannot create diverse spatiotemporal patterns on its own; however, given temporally heterogeneous input, the AL generated realistic firing patterns. Finally, given the temporally structured input provided by ORNs, we clarified several separate, additional contributions of the AL to olfactory information processing. Thus, our results demonstrate the origin and subsequent reformatting of spatiotemporal neural codes for odors. PMID:20147528

Parallel representation of stimulus identity and intensity in a dual pathway model inspired by the olfactory system of the honeybee.

PubMed

Schmuker, Michael; Yamagata, Nobuhiro; Nawrot, Martin Paul; Menzel, Randolf

2011-01-01

The honeybee Apis mellifera has a remarkable ability to detect and locate food sources during foraging, and to associate odor cues with food rewards. In the honeybee's olfactory system, sensory input is first processed in the antennal lobe (AL) network. Uniglomerular projection neurons (PNs) convey the sensory code from the AL to higher brain regions via two parallel but anatomically distinct pathways, the lateral and the medial antenno-cerebral tract (l- and m-ACT). Neurons innervating either tract show characteristic differences in odor selectivity, concentration dependence, and representation of mixtures. It is still unknown how this differential stimulus representation is achieved within the AL network. In this contribution, we use a computational network model to demonstrate that the experimentally observed features of odor coding in PNs can be reproduced by varying lateral inhibition and gain control in an otherwise unchanged AL network. We show that odor coding in the l-ACT supports detection and accurate identification of weak odor traces at the expense of concentration sensitivity, while odor coding in the m-ACT provides the basis for the computation and following of concentration gradients but provides weaker discrimination power. Both coding strategies are mutually exclusive, which creates a tradeoff between detection accuracy and sensitivity. The development of two parallel systems may thus reflect an evolutionary solution to this problem that enables honeybees to achieve both tasks during bee foraging in their natural environment, and which could inspire the development of artificial chemosensory devices for odor-guided navigation in robots.

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

PubMed Central

Cheung, Man C.; Jang, Woochan; Schwob, James E.; Wachowiak, Matt

2014-01-01

The olfactory system has a unique capacity for recovery from peripheral damage. After injury to the olfactory epithelium (OE), olfactory sensory neurons (OSNs) regenerate and re-converge on target glomeruli of the olfactory bulb (OB). Thus far, this process has been described anatomically for only a few defined populations of OSNs. Here we characterize this regeneration at a functional level by assessing how odor representations carried by OSN inputs to the OB recover after massive loss and regeneration of the sensory neuron population. We used chronic imaging of mice expressing synaptopHluorin in OSNs to monitor odor representations in the dorsal OB before lesion by the olfactotoxin methyl bromide and after a 12 week recovery period. Methyl bromide eliminated functional inputs to the OB, and these inputs recovered to near-normal levels of response magnitude within 12 weeks. We also found that the functional topography of odor representations recovered after lesion, with odorants evoking OSN input to glomerular foci within the same functional domains as before lesion. At a finer spatial scale, however, we found evidence for mistargeting of regenerated OSN axons onto OB targets, with odorants evoking synaptopHluorin signals in small foci that did not conform to a typical glomerular structure but whose distribution was nonetheless odorant-specific. These results indicate that OSNs have a robust ability to reestablish functional inputs to the OB and that the mechanisms underlying the topography of bulbar reinnervation during development persist in the adult and allow primary sensory representations to be largely restored after massive sensory neuron loss. PMID:24431990

Ventromedial hypothalamic nucleus lesions disrupt olfactory mate recognition and receptivity in female ferrets

PubMed Central

Robarts, Daniel W.; Baum, Michael J.

2008-01-01

Previous research showed that ferrets of both sexes rely on the perception of conspecifics’ body odors to identify and motivate approach towards opposite-sex mating partners, and exposure to male body odors stimulated Fos expression in an olfactory projection circuit of female, but not male, ferrets that terminates in the ventromedial hypothalamic nucleus (VMH). We asked whether the female-typical preference of ferrets to approach male as opposed to female body odors in Y-maze tests would be disrupted by VMH lesions. Sexually experienced female ferrets were ovo-hysterectomized prior to receiving bilateral electrolytic lesions of the VMH, the preoptic area/anterior hypothalamus (POA/AH) or a sham operation. Subsequently, while receiving estradiol benzoate, females that received either complete or partial bilateral lesions of the VMH approached volatile odors from an anesthetized male on significantly fewer trials than females given POA/AH lesions or a sham operation. Both groups of ferrets with VMH lesion damage reliably discriminated between volatile anal scents as well as urinary odors from the 2 sexes in home cage habituation/dishabituation tests, suggesting that their odor-based sex discrimination remained intact. Females with complete bilateral VMH lesions showed significantly lower acceptance of neck gripping from a stimulus male (receptivity) and more aggression towards the male than all other groups of female subjects. Estrogen-sensitive neurons in the VMH appear to play a central role in female-typical neural processing of odor inputs leading to a preference to seek out a male sex partner, in addition to facilitating females’ sexual receptivity. PMID:17011561

Imaging of odor perception delineates functional disintegration of the limbic circuits in mesial temporal lobe epilepsy.

PubMed

Ciumas, Carolina; Lindström, Per; Aoun, Bernard; Savic, Ivanka

2008-01-15

Metabolic and neuro-receptor abnormalities within the extrafocal limbic circuits are established in mesial temporal lobe epilepsy (MTLE). However, very little is known about how these circuits process external stimuli. We tested whether odor activation can help delineate limbic functional disintegration in MTLE, and measured cerebral blood flow with PET during birhinal smelling of familiar and unfamiliar odors, using smelling of odorless air as the baseline condition. Patients with MTLE (13 left-sided, 10 right-sided) and 21 controls were investigated. In addition to odor activation, the analysis included functional connectivity, using right and left piriform cortex as seed regions. Healthy controls activated the amygdala, piriform, anterior insular, and cingulate cortices on both sides. Smelling of familiar odors engaged, in addition, the right parahippocampus, and the left Brodmann Area (BA) 44, 45, 47. Patients failed to activate the amygdala, piriform and the anterior insular cortex in the epileptogenic hemisphere. Furthermore, those with left MTLE did not activate the left BA 44, 45 and 47 with familiar odors, which they perceived as less familiar than controls. Congruent with the activation data each seed region was in patients functionally disconnected with the contralateral amygdala+piriform+insular cortex. The functional disintegration in patients exceeded the reduced activation, and included the contralateral temporal neocortex, and in subjects with right MTLE also the right orbitofrontal cortex. Imaging of odor perception may be used to delineate functional disintegration of the limbic networks in MTLE. It shows an altered response in several regions, which may underlie some interictal behavioral problems associated with this condition.

Neurobiology of secure infant attachment and attachment despite adversity: a mouse model.

PubMed

Roth, T L; Raineki, C; Salstein, L; Perry, R; Sullivan-Wilson, T A; Sloan, A; Lalji, B; Hammock, E; Wilson, D A; Levitt, P; Okutani, F; Kaba, H; Sullivan, R M

2013-10-01

Attachment to an abusive caregiver has wide phylogenetic representation, suggesting that animal models are useful in understanding the neural basis underlying this phenomenon and subsequent behavioral outcomes. We previously developed a rat model, in which we use classical conditioning to parallel learning processes evoked during secure attachment (odor-stroke, with stroke mimicking tactile stimulation from the caregiver) or attachment despite adversity (odor-shock, with shock mimicking maltreatment). Here we extend this model to mice. We conditioned infant mice (postnatal day (PN) 7-9 or 13-14) with presentations of peppermint odor and either stroking or shock. We used (14) C 2-deoxyglucose (2-DG) to assess olfactory bulb and amygdala metabolic changes following learning. PN7-9 mice learned to prefer an odor following either odor-stroke or shock conditioning, whereas odor-shock conditioning at PN13-14 resulted in aversion/fear learning. 2-DG data indicated enhanced bulbar activity in PN7-9 preference learning, whereas significant amygdala activity was present following aversion learning at PN13-14. Overall, the mouse results parallel behavioral and neural results in the rat model of attachment, and provide the foundation for the use of transgenic and knockout models to assess the impact of both genetic (biological vulnerabilities) and environmental factors (abusive) on attachment-related behaviors and behavioral development. © 2013 John Wiley & Sons Ltd and International Behavioural and Neural Genetics Society.

Multivariate prediction of odor from pig production based on in-situ measurement of odorants

NASA Astrophysics Data System (ADS)

Hansen, Michael J.; Jonassen, Kristoffer E. N.; Løkke, Mette Marie; Adamsen, Anders Peter S.; Feilberg, Anders

2016-06-01

The aim of the present study was to estimate a prediction model for odor from pig production facilities based on measurements of odorants by Proton-Transfer-Reaction Mass spectrometry (PTR-MS). Odor measurements were performed at four different pig production facilities with and without odor abatement technologies using a newly developed mobile odor laboratory equipped with a PTR-MS for measuring odorants and an olfactometer for measuring the odor concentration by human panelists. A total of 115 odor measurements were carried out in the mobile laboratory and simultaneously air samples were collected in Nalophan bags and analyzed at accredited laboratories after 24 h. The dataset was divided into a calibration dataset containing 94 samples and a validation dataset containing 21 samples. The prediction model based on the measurements in the mobile laboratory was able to explain 74% of the variation in the odor concentration based on odorants, whereas the prediction models based on odor measurements with bag samples explained only 46-57%. This study is the first application of direct field olfactometry to livestock odor and emphasizes the importance of avoiding any bias from sample storage in studies of odor-odorant relationships. Application of the model on the validation dataset gave a high correlation between predicted and measured odor concentration (R2 = 0.77). Significant odorants in the prediction models include phenols and indoles. In conclusion, measurements of odorants on-site in pig production facilities is an alternative to dynamic olfactometry that can be applied for measuring odor from pig houses and the effects of odor abatement technologies.

Methods of human body odor sampling: the effect of freezing.

PubMed

Lenochova, Pavlina; Roberts, S Craig; Havlicek, Jan

2009-02-01

Body odor sampling is an essential tool in human chemical ecology research. However, methodologies of individual studies vary widely in terms of sampling material, length of sampling, and sample processing. Although these differences might have a critical impact on results obtained, almost no studies test validity of current methods. Here, we focused on the effect of freezing samples between collection and use in experiments involving body odor perception. In 2 experiments, we tested whether axillary odors were perceived differently by raters when presented fresh or having been frozen and whether several freeze-thaw cycles affected sample quality. In the first experiment, samples were frozen for 2 weeks, 1 month, or 4 months. We found no differences in ratings of pleasantness, attractiveness, or masculinity between fresh and frozen samples. Similarly, almost no differences between repeatedly thawed and fresh samples were found. We found some variations in intensity; however, this was unrelated to length of storage. The second experiment tested differences between fresh samples and those frozen for 6 months. Again no differences in subjective ratings were observed. These results suggest that freezing has no significant effect on perceived odor hedonicity and that samples can be reliably used after storage for relatively long periods.

Investigation of sensory profiles and hedonic drivers of emerging aquaculture fish species.

PubMed

Alexi, Niki; Byrne, Derek V; Nanou, Evangelia; Grigorakis, Kriton

2018-02-01

The aquaculture sector needs to increase the diversity fish species and their processed products to cover rising consumer demands. Candidates for this diversification have been identified to be meagre, greater amberjack, pikeperch and wreckfish. Yet scientific knowledge on their sensory profiles and consumer hedonic responses is scarce. The aim of the current study was to investigate these aspects, since they are essential for product development and market targeting. Species exhibited different sensory profiles with the exception of the odor/flavor profiles of meagre and greater amberjack, which were similar. Texture was more important than odor/flavor in explaining interspecies differences. Yet the hedonic responses were equally related to texture and odor/flavor. None of the species received negative hedonic scores. Both positive and negative hedonic drivers were identified within the odor/flavor and texture modalities. The distinct profiles of meagre, greater amberjack, pikeperch and wreckfish make these fish species valuable first materials for new product development and for covering markets with different sensory preferences. Differences in fish texture are more easily perceivable, yet small variations in fish odor/flavor can have a great impact on consumers' hedonic responses. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Honeybees (Apis mellifera) learn to discriminate the smell of organic compounds from their respective deuterated isotopomers

PubMed Central

Gronenberg, Wulfila; Raikhelkar, Ajay; Abshire, Eric; Stevens, Jennifer; Epstein, Eric; Loyola, Karin; Rauscher, Michael; Buchmann, Stephen

2014-01-01

The understanding of physiological and molecular processes underlying the sense of smell has made considerable progress during the past three decades, revealing the cascade of molecular steps that lead to the activation of olfactory receptor (OR) neurons. However, the mode of primary interaction of odorant molecules with the OR proteins within the sensory cells is still enigmatic. Two different concepts try to explain these interactions: the ‘odotope hypothesis’ suggests that OR proteins recognize structural aspects of the odorant molecule, whereas the ‘vibration hypothesis’ proposes that intra-molecular vibrations are the basis for the recognition of the odorant by the receptor protein. The vibration hypothesis predicts that OR proteins should be able to discriminate compounds containing deuterium from their common counterparts which contain hydrogen instead of deuterium. This study tests this prediction in honeybees (Apis mellifera) using the proboscis extension reflex learning in a differential conditioning paradigm. Rewarding one odour (e.g. a deuterated compound) with sucrose and not rewarding the respective analogue (e.g. hydrogen-based odorant) shows that honeybees readily learn to discriminate hydrogen-based odorants from their deuterated counterparts and supports the idea that intra-molecular vibrations may contribute to odour discrimination. PMID:24452031

Characterizing odors from cattle feedlots with different odor techniques

USDA-ARS?s Scientific Manuscript database

Odors from cattle feedlots negatively affect local communities. The purpose of this study was to characterize odors and odorants using different odor sampling techniques. Odors were characterized with field olfactometers (Nasal Ranger®), sensory techniques (GC-O) and analytical techniques (sorbent t...

[Characteristics of odors and VOCs from sludge direct drying process].

PubMed

Chen, Wen-He; Deng, Ming-Jia; Luo, Hui; Zhang, Jing-Ying; Ding, Wen-Jie; Liu, Jun-Xin; Liu, Jun-Xin

2014-08-01

Co-processing sewage sludge by using the high-temperature feature of cement kiln can realize harmless disposal and energy recycling. In this paper, investigation on characteristics of the flue gas from sludge drying process was carried out in Guangzhou Heidelberg Yuexiu Cement Co., LTD. The composition and the main source of odors and volatile organic compounds (VOCs) emitted during the drying process were analyzed, aimed to provide scientific basis for the treatment of sewage sludge. Results showed that there were a large number of malodorous substances and VOCs in the flue gas. Sulfur dioxide and other sulfur-containing compounds were the main components in the malodorous substances, while benzene derivatives were predominant in VOCs. The compositions of odors and VOCs were influenced by the characteristics of the sludge and the heat medium (kiln tail gas). Total organic compounds in the sludge were significantly decreased after drying. Other organic substances such as volatile fatty acid, protein, and polysaccharide were also obviously reduced. The organic matter in sludge was the main source of VOCs in the flue gas. Part of sulfurous substances, such as sulfur dioxide, carbon disulfide, were from sulfur-containing substances in the sludge, and the rest were from the kiln tail gas itself.

The transcriptional regulatory network of Corynebacterium jeikeium K411 and its interaction with metabolic routes contributing to human body odor formation.

PubMed

Barzantny, Helena; Schröder, Jasmin; Strotmeier, Jasmin; Fredrich, Eugenie; Brune, Iris; Tauch, Andreas

2012-06-15

Lipophilic corynebacteria are involved in the generation of volatile odorous products in the process of human body odor formation by degrading skin lipids and specific odor precursors. Therefore, these bacteria represent appropriate model systems for the cosmetic industry to examine axillary malodor formation on the molecular level. To understand the transcriptional control of metabolic pathways involved in this process, the transcriptional regulatory network of the lipophilic axilla isolate Corynebacterium jeikeium K411 was reconstructed from the complete genome sequence. This bioinformatic approach detected a gene-regulatory repertoire of 83 candidate proteins, including 56 DNA-binding transcriptional regulators, nine two-component systems, nine sigma factors, and nine regulators with diverse physiological functions. Furthermore, a cross-genome comparison among selected corynebacterial species of the taxonomic cluster 3 revealed a common gene-regulatory repertoire of 44 transcriptional regulators, including the MarR-like regulator Jk0257, which is exclusively encoded in the genomes of this taxonomical subline. The current network reconstruction comprises 48 transcriptional regulators and 674 gene-regulatory interactions that were assigned to five interconnected functional modules. Most genes involved in lipid degradation are under the combined control of the global cAMP-sensing transcriptional regulator GlxR and the LuxR-family regulator RamA, probably reflecting the essential role of lipid degradation in C. jeikeium. This study provides the first genome-scale in silico analysis of the transcriptional regulation of metabolism in a lipophilic bacterium involved in the formation of human body odor. Copyright © 2012 Elsevier B.V. All rights reserved.

Walking patterns induced by learned odors in the honeybee, Apis mellifera L.

PubMed

Yamashita, Toshiya; Haupt, S Shuichi; Ikeno, Hidetoshi; Ai, Hiroyuki

2016-01-01

The odor localization strategy induced by odors learned via differential conditioning of the proboscis extension response was investigated in honeybees. In response to reward-associated but not non-reward-associated odors, learners walked longer paths than non-learners and control bees. When orange odor reward association was learned, the path length and the body turn angles were small during odor stimulation and greatly increased after stimulation ceased. In response to orange odor, bees walked locally with alternate left and right turns during odor stimulation to search for the reward-associated odor source. After odor stimulation, bees walked long paths with large turn angles to explore the odor plume. For clove odor, learning-related modulations of locomotion were less pronounced, presumably due to a spontaneous preference for orange in the tested population of bees. This study is the first to describe how an odor-reward association modulates odor-induced walking in bees. © 2016. Published by The Company of Biologists Ltd.

Effects of vomeronasal organ removal on individual odor discrimination, sex-odor preference, and scent marking by female hamsters.

PubMed

Petrulis, A; Peng, M; Johnston, R E

1999-03-01

Removal of the vomeronasal organ (VNX) did not eliminate the ability of female hamsters to discriminate between individual male's flank gland or urine odors in a habituation/discrimination task nor did it impair preference for male odors over female odors from a distance. Vomeronasal organ removal did reduce overall levels of investigation of flank gland odor in the habituation/discrimination task. Although VNX females did not show severe impairments in the frequency of either flank or vaginal marking in response to odors, they did show an abnormal pattern of marking. VNX females, unlike shams, did not flank mark more to female odors than to male odors, nor did they vaginal mark more to male odors than to female odors. Thus, the vomeronasal organ in female hamsters appears to be important for differences in scent marking toward male and female odors, but is not essential for discrimination of individual odors or for preferences for male over female odors.

Relations between hydrology, water quality, and taste-and-odor causing organisms and compounds in Lake Houston, Texas, April 2006-September 2008

USGS Publications Warehouse

Beussink, Amy M.; Graham, Jennifer L.

2011-01-01

Lake Houston is a surface-water-supply reservoir and an important recreational resource for the city of Houston, Texas. Growing concerns over water quality in Lake Houston prompted a detailed assessment of water quality in the reservoir. The assessment focused on water-quality constituents that affect the aesthetic quality of drinking water. The hydrologic and water-quality conditions influencing the occurrence of taste-and-odor causing organisms and compounds in Lake Houston were assessed using discrete and continuously monitored water-quality data collected during April 2006– September 2008. The hydrology of Lake Houston is characterized by rapidly changing conditions. During inflow events, water residence time can change by orders of magnitude within a matter of hours. Likewise, the reservoir can stratify and destratify over a period of several hours, even during non-summer and at relatively short water residence times, given extended periods with warm temperatures and little wind. The rapidly changing hydrology likely influences all other aspects of water quality in Lake Houston, including the occurrence of taste-and-odor causing organisms and compounds. Water quality in Lake Houston varied with respect to season and water residence time but typically was indicative of turbid, eutrophic to hypereutrophic conditions. In general, turbidity and nutrient concentrations were largest during non-summer (October–May) and when water residence times were relatively short (less than 100 days), which reflects the influence of inflow events on water-quality conditions. Large inflow events can cause substantial changes in water-quality conditions over relatively short periods of time (hours). The taste-and-odor causing organisms cyanobacteria and actinomycetes bacteria were always present in Lake Houston. Cyanobacterial biovolume was largest during summer (June– September) and when water residence time was greater than 100 days. Annual maxima in cyanobacterial biovolume occurred during July-September of each year, when temperatures were larger than 27 degrees Celsius and water residence times were longer than 400 days. In contrast, actinomycetes bacteria were most abundant during non-summer and when water residence times were less than 100 days, reflecting the close association between these organisms and transport of suspended sediments. Geosmin and 2-methylisoborneol are the taste-and-odor causing compounds most commonly produced by cyanobacteria and actinomycetes bacteria. Geosmin was detected more frequently (62 percent of samples) than 2-methylisoborneol (29 percent of samples) in Lake Houston. Geosmin exceeded the human detection threshold (10 nanograms per liter) only once during the study period and 2-methylisoborneol exceeded the human detection threshold twice. Manganese is a naturally occurring trace element that can occasionally cause taste-andodor problems in drinking water. Manganese concentrations exceeded the human detection threshold (about 50 micrograms per liter) in about 50 percent of samples collected near the surface and 84 percent of samples collected near the bottom. The cyanotoxin microcystin was detected relatively infrequently (16 percent of samples) and at small concentrations (less than or equal to 0.2 micrograms per liter). The abundance of the taste-and-odor causing organisms cyanobacteria and actinomycetes bacteria in Lake Houston was coupled with inflow events and subsequent changes in water-quality conditions. Cyanobacterial biovolume (biomass) in Lake Houston was largest during warm periods with little inflow and relatively small turbidity values. In contrast, actinomycetes bacteria were most abundant following inflow events when turbidity was relatively large. Severe taste-and-odor problems were not observed during the study period, precluding quantification of the hydrologic and water-quality conditions associated with large concentrations of taste-and-odor causing compounds and development of predictive models. Reservoir inflow (water residence time) and turbidity, variables related to the abundance of potential taste-andodor causing organisms, are currently (2011) continuously measured in Lake Houston, and predictive models could be developed in the future when the hydrologic and water-quality conditions associated with taste-and-odor problems have been better quantified. Seasonal and water residence time influences on water-quality conditions altered relations between hydrologic and water-quality conditions and taste-and-odor causing organisms and compounds. Future data collection and development of predictive models need to account for the variability associated with season and water residence time. 

Serotonin modulates the population activity profile of olfactory bulb external tufted cells

PubMed Central

Liu, Shaolin; Aungst, Jason L.; Puche, Adam C.

2012-01-01

Serotonergic neurons in the raphe nuclei constitute one of the most prominent neuromodulatory systems in the brain. Projections from the dorsal and median raphe nuclei provide dense serotonergic innervation of the glomeruli of olfactory bulb. Odor information is initially processed by glomeruli, thus serotonergic modulation of glomerular circuits impacts all subsequent odor coding in the olfactory system. The present study discloses that serotonin (5-HT) produces excitatory modulation of external tufted (ET) cells, a pivotal neuron in the operation of glomerular circuits. The modulation is due to a transient receptor potential (TRP) channel-mediated inward current induced by activation of 5-HT2A receptors. This current produces membrane depolarization and increased bursting frequency in ET cells. Interestingly, the magnitude of the inward current and increased bursting inversely correlate with ET cell spontaneous (intrinsic) bursting frequency: slower bursting ET cells are more strongly modulated than faster bursting cells. Serotonin thus differentially impacts ET cells such that the mean bursting frequency of the population is increased. This centrifugal modulation could impact odor processing by: 1) increasing ET cell excitatory drive on inhibitory neurons to increase presynaptic inhibition of olfactory sensory inputs and postsynaptic inhibition of mitral/tufted cells; and/or 2) coordinating ET cell bursting with exploratory sniffing frequencies (5–8 Hz) to facilitate odor coding. PMID:22013233

Reward for food odors: an fMRI study of liking and wanting as a function of metabolic state and BMI

PubMed Central

Jiang, Tao; Soussignan, Robert; Schaal, Benoist

2015-01-01

Brain reward systems mediate liking and wanting for food reward. Here, we explore the differential involvement of the following structures for these two components: the ventral and dorsal striatopallidal area, orbitofrontal cortex (OFC), anterior insula and anterior cingulate. Twelve healthy female participants were asked to rate pleasantness (liking of food and non-food odors) and the desire to eat (wanting of odor-evoked food) during event-related functional magnetic resonance imaging (fMRI). The subjective ratings and fMRI were performed in hunger and satiety states. Activations of regions of interest were compared as a function of task (liking vs wanting), odor category (food vs non-food) and metabolic state (hunger vs satiety). We found that the nucleus accumbens and ventral pallidum were differentially involved in liking or wanting during the hunger state, which suggests a reciprocal inhibitory influence between these structures. Neural activation of OFC subregions was correlated with either liking or wanting ratings, suggesting an OFC role in reward processing magnitude. Finally, during the hunger state, participants with a high body mass index exhibited less activation in neural structures underlying food reward processing. Our results suggest that food liking and wanting are two separable psychological constructs and may be functionally segregated within the cortico-striatopallidal circuit. PMID:24948157

Odour emissions from poultry litter - A review litter properties, odour formation and odorant emissions from porous materials.

PubMed

Dunlop, Mark W; Blackall, Patrick J; Stuetz, Richard M

2016-07-15

Odour emissions from meat chicken sheds can at times cause odour impacts on surrounding communities. Litter is seen as the primary source of this odour. Formation and emission of odour from meat chicken litter during the grow-out period are influenced by various factors such as litter conditions, the environment, microbial activity, properties of the odorous gases and management practices. Odour emissions vary spatially and temporally. This variability has made it challenging to understand how specific litter conditions contribute to odour emissions from the litter and production sheds. Existing knowledge on odorants, odour formation mechanisms and emission processes that contribute to odour emissions from litter are reviewed. Litter moisture content and water thermodynamics (i.e. water activity, Aw) are also examined as factors that contribute to microbial odour formation, physical litter conditions and the exchange of individual odorant gases at the air-water interface. Substantial opportunities exist for future research on litter conditions and litter formation mechanisms and how these contribute to odour emissions. Closing this knowledge gap will improve management strategies that intercept and interfere with odour formation and emission processes leading to an overall reduction in the potential to cause community impacts. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

Nonassociative Plasticity Alters Competitive Interactions Among Mixture Components In Early Olfactory Processing

PubMed Central

Locatelli, Fernando F; Fernandez, Patricia C; Villareal, Francis; Muezzinoglu, Kerem; Huerta, Ramon; Galizia, C. Giovanni; Smith, Brian H.

2012-01-01

Experience related plasticity is an essential component of networks involved in early olfactory processing. However, the mechanisms and functions of plasticity in these neural networks are not well understood. We studied nonassociative plasticity by evaluating responses to two pure odors (A and X) and their binary mixture using calcium imaging of odor elicited activity in output neurons of the honey bee antennal lobe. Unreinforced exposure to A or X produced no change in the neural response elicited by the pure odors. However, exposure to one odor (e.g. A) caused the response to the mixture to become more similar to the other component (X). We also show in behavioral analyses that unreinforced exposure to A caused the mixture to become perceptually more similar to X. These results suggest that nonassociative plasticity modifies neural networks in such a way that it affects local competitive interactions among mixture components. We used a computational model to evaluate the most likely targets for modification. Hebbian modification of synapses from inhibitory local interneurons to projection neurons most reliably produces the observed shift in response to the mixture. These results are consistent with a model in which the antennal lobe acts to filter olfactory information according to its relevance for performing a particular task. PMID:23167675

Pleasant and Unpleasant Odors Influence Hedonic Evaluations of Human Faces: An Event-Related Potential Study.

PubMed

Cook, Stephanie; Fallon, Nicholas; Wright, Hazel; Thomas, Anna; Giesbrecht, Timo; Field, Matt; Stancak, Andrej

2015-01-01

Odors can alter hedonic evaluations of human faces, but the neural mechanisms of such effects are poorly understood. The present study aimed to analyze the neural underpinning of odor-induced changes in evaluations of human faces in an odor-priming paradigm, using event-related potentials (ERPs). Healthy, young participants (N = 20) rated neutral faces presented after a 3 s pulse of a pleasant odor (jasmine), unpleasant odor (methylmercaptan), or no-odor control (clean air). Neutral faces presented in the pleasant odor condition were rated more pleasant than the same faces presented in the no-odor control condition, which in turn were rated more pleasant than faces in the unpleasant odor condition. Analysis of face-related potentials revealed four clusters of electrodes significantly affected by odor condition at specific time points during long-latency epochs (600-950 ms). In the 620-640 ms interval, two scalp-time clusters showed greater negative potential in the right parietal electrodes in response to faces in the pleasant odor condition, compared to those in the no-odor and unpleasant odor conditions. At 926 ms, face-related potentials showed greater positivity in response to faces in the pleasant and unpleasant odor conditions at the left and right lateral frontal-temporal electrodes, respectively. Our data shows that odor-induced shifts in evaluations of faces were associated with amplitude changes in the late (>600) and ultra-late (>900 ms) latency epochs. The observed amplitude changes during the ultra-late epoch are consistent with a left/right hemisphere bias towards pleasant/unpleasant odor effects. Odors alter evaluations of human faces, even when there is a temporal lag between presentation of odors and faces. Our results provide an initial understanding of the neural mechanisms underlying effects of odors on hedonic evaluations.

Pleasant and Unpleasant Odors Influence Hedonic Evaluations of Human Faces: An Event-Related Potential Study

PubMed Central

Cook, Stephanie; Fallon, Nicholas; Wright, Hazel; Thomas, Anna; Giesbrecht, Timo; Field, Matt; Stancak, Andrej

2015-01-01

Odors can alter hedonic evaluations of human faces, but the neural mechanisms of such effects are poorly understood. The present study aimed to analyze the neural underpinning of odor-induced changes in evaluations of human faces in an odor-priming paradigm, using event-related potentials (ERPs). Healthy, young participants (N = 20) rated neutral faces presented after a 3 s pulse of a pleasant odor (jasmine), unpleasant odor (methylmercaptan), or no-odor control (clean air). Neutral faces presented in the pleasant odor condition were rated more pleasant than the same faces presented in the no-odor control condition, which in turn were rated more pleasant than faces in the unpleasant odor condition. Analysis of face-related potentials revealed four clusters of electrodes significantly affected by odor condition at specific time points during long-latency epochs (600−950 ms). In the 620−640 ms interval, two scalp-time clusters showed greater negative potential in the right parietal electrodes in response to faces in the pleasant odor condition, compared to those in the no-odor and unpleasant odor conditions. At 926 ms, face-related potentials showed greater positivity in response to faces in the pleasant and unpleasant odor conditions at the left and right lateral frontal-temporal electrodes, respectively. Our data shows that odor-induced shifts in evaluations of faces were associated with amplitude changes in the late (>600) and ultra-late (>900 ms) latency epochs. The observed amplitude changes during the ultra-late epoch are consistent with a left/right hemisphere bias towards pleasant/unpleasant odor effects. Odors alter evaluations of human faces, even when there is a temporal lag between presentation of odors and faces. Our results provide an initial understanding of the neural mechanisms underlying effects of odors on hedonic evaluations. PMID:26733843

ESTROGEN REPLACEMENT THERAPY INDUCES FUNCTIONAL ASYMMETRY ON AN ODOR MEMORY/DISCRIMINATION TEST

PubMed Central

Doty, Richard L.; Kisat, Mehreen; Tourbier, Isabelle

2008-01-01

The secondary afferents of the olfactory system largely project to the ipsilateral cortex without synapsing in the thalamus, making unilateral olfactory testing a useful probe of ipsilateral hemispheric activity. In light of evidence that lateralized performance on some perceptual tasks may be influenced by estrogen, we assessed left:right nostril differences in two measures of olfactory function in 14 post-menopausal women receiving estrogen replacement therapy (ERT) and 48 post-menopausal women receiving no such therapy. Relative to women not taking ERT, those receiving ERT exhibited better performance in the left nostril and poorer performance in the right nostril on an odor memory/discrimination test. Similar laterality effects were not observed for an odor detection threshold test employing phenyl ethyl alcohol. These results suggest that estrogen influences the lateralization of an odor memory/discrimination task and that hormone replacement therapy in the menopause may be an excellent paradigm for understanding lateralizing effects of hormones on some sensory processes. PMID:18466883

Neural relativity principle

NASA Astrophysics Data System (ADS)

Koulakov, Alexei

Olfaction is the final frontier of our senses - the one that is still almost completely mysterious to us. Despite extensive genetic and perceptual data, and a strong push to solve the neural coding problem, fundamental questions about the sense of smell remain unresolved. Unlike vision and hearing, where relatively straightforward relationships between stimulus features and neural responses have been foundational to our understanding sensory processing, it has been difficult to quantify the properties of odorant molecules that lead to olfactory percepts. In a sense, we do not have olfactory analogs of ``red'', ``green'' and ``blue''. The seminal work of Linda Buck and Richard Axel identified a diverse family of about 1000 receptor molecules that serve as odorant sensors in the nose. However, the properties of smells that these receptors detect remain a mystery. I will review our current understanding of the molecular properties important to the olfactory system. I will also describe a theory that explains how odorant identity can be preserved despite substantial changes in the odorant concentration.

Identification of characteristic aroma compounds in raw and thermally processed African giant snail (Achatina fulica).

PubMed

Lasekan, Ola; Muniady, Megala; Lin, Mee; Dabaj, Fatma

2018-04-24

Food flavor appreciation is one of the first signals along with food appearance and texture encountered by consumers during eating of food. Also, it is well known that flavor can strongly influence consumer's acceptability judgment. The increase in the consumption of snail meat across the world calls for the need to research into the aroma compounds responsible for the distinctive aroma notes of processed snail meat. The odorants responsible for the unique aroma notes in thermally processed giant African snail meats were evaluated by means of aroma extract dilution analysis (AEDA), gas chromatography-olfactometry (GC-O) and odor activity values (OAVs) respectively. Results revealed significant differences in the aroma profiles of the raw and thermally processed snail meats. Whilst the aroma profile of the raw snail meat was dominated with the floral-like β-ionone and β-iso-methyl ionone, sweaty/cheesy-like butanoic acid, and the mushroom-like 1-octen-3-one, the boiled and fried samples were dominated with the thermally generated odorants like 2-methylpyrazine, 2,5-dimethylpyrazine, 2-acetylthiazole and 2-acetylpyridine. Finally, results have shown that sotolon, 2-acetyl-1-pyrroline, 2-furanmethanethiol, 2-methylbutanal, 1-octen-3-one, octanal, furanone, 2-methoxyphenol, 2-acetylpyridine, 2-acetylthiazole, and 2-methylpyrazine contributed to the overall aroma of the thermally processed snail meat.

What's that smell? An ecological approach to understanding preferences for familiar odors.

PubMed

Schloss, Karen B; Goldberger, Carolyn S; Palmer, Stephen E; Levitan, Carmel A

2015-01-01

How do odor preferences arise? Following Palmer and Schloss's (2010, PNAS, 107, 8877-8882) ecological valence theory of color preferences, we propose that preference for an odor is determined by preferences for all objects and/or entities associated with that odor. The present results showed that preferences for familiar odors were strongly predicted by average preferences for all things associated with the odors (eg people liked the apple odor which was associated with mostly positive things, such as apples, soap, and candy, but disliked the fish odor, which was associated with mostly negative things, such as dead fish, trash, and vomit). The odor WAVEs (weighted affective valence estimates) performed significantly better than one based on preference for only the namesake object (eg predicting preference for the apple odor based on preference for apples). These results suggest that preferences for familiar odors are based on a summary statistic, coding the valence of previous odor-related experiences. We discuss how this account of odor preferences is consistent with the idea that odor preferences exist to guide organisms to approach beneficial objects and situations and avoid harmful ones.

Assessing implicit odor localization in humans using a cross-modal spatial cueing paradigm.

PubMed

Moessnang, Carolin; Finkelmeyer, Andreas; Vossen, Alexandra; Schneider, Frank; Habel, Ute

2011-01-01

Navigation based on chemosensory information is one of the most important skills in the animal kingdom. Studies on odor localization suggest that humans have lost this ability. However, the experimental approaches used so far were limited to explicit judgements, which might ignore a residual ability for directional smelling on an implicit level without conscious appraisal. A novel cueing paradigm was developed in order to determine whether an implicit ability for directional smelling exists. Participants performed a visual two-alternative forced choice task in which the target was preceded either by a side-congruent or a side-incongruent olfactory spatial cue. An explicit odor localization task was implemented in a second experiment. No effect of cue congruency on mean reaction times could be found. However, a time by condition interaction emerged, with significantly slower responses to congruently compared to incongruently cued targets at the beginning of the experiment. This cueing effect gradually disappeared throughout the course of the experiment. In addition, participants performed at chance level in the explicit odor localization task, thus confirming the results of previous research. The implicit cueing task suggests the existence of spatial information processing in the olfactory system. Response slowing after a side-congruent olfactory cue is interpreted as a cross-modal attentional interference effect. In addition, habituation might have led to a gradual disappearance of the cueing effect. It is concluded that under immobile conditions with passive monorhinal stimulation, humans are unable to explicitly determine the location of a pure odorant. Implicitly, however, odor localization seems to exert an influence on human behaviour. To our knowledge, these data are the first to show implicit effects of odor localization on overt human behaviour and thus support the hypothesis of residual directional smelling in humans. © 2011 Moessnang et al.

A quick responding quartz crystal microbalance sensor array based on molecular imprinted polyacrylic acids coating for selective identification of aldehydes in body odor.

PubMed

Jha, Sunil K; Hayashi, Kenshi

2015-03-01

In present work, a novel quartz crystal microbalance (QCM) sensor array has been developed for prompt identification of primary aldehydes in human body odor. Molecularly imprinted polymers (MIP) are prepared using the polyacrylic acid (PAA) polymer matrix and three organic acids (propenoic acid, hexanoic acid and octanoic acid) as template molecules, and utilized as QCM surface coating layer. The performance of MIP films is characterized by 4-element QCM sensor array (three coated with MIP layers and one with pure PAA for reference) dynamic and static responses to target aldehydes: hexanal, heptanal, and nonanal in single, binary, and tertiary mixtures at distinct concentrations. The target aldehydes were selected subsequent to characterization of body odor samples with solid phase-micro extraction gas chromatography mass spectrometer (SPME-GC-MS). The hexanoic acid and octanoic acid imprinted PAA exhibit fast response, and better sensitivity, selectivity and reproducibility than the propenoic acid, and non-imprinted PAA in array. The response time and recovery time for hexanoic acid imprinted PAA are obtained as 5 s and 12 s respectively to typical concentrations of binary and tertiary mixtures of aldehydes using the static response. Dynamic sensor array response matrix has been processed with principal component analysis (PCA) for visual, and support vector machine (SVM) classifier for quantitative identification of target odors. Aldehyde odors were identified successfully in principal component (PC) space. SVM classifier results maximum recognition rate 79% for three classes of binary odors and 83% including single, binary, and tertiary odor classes in 3-fold cross validation. Copyright © 2014 Elsevier B.V. All rights reserved.

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

PubMed Central

Schablitzky, Sylvia; Pause, Bettina M.

2014-01-01

Major depressive disorder (MDD) occurs with a high prevalence among mental illnesses. MDD patients experience sadness and hopelessness, with blunted affective reactivity. However, such depressive episodes are also key symptoms in other depressive disorders, like Bipolar Disorder (BPD) or Seasonal Affective Disorder (SAD). Moreover, depressive symptoms can also be found in healthy individuals, but are experienced as less severe or for a shorter duration than in patients. Here, it is aimed to summarize studies investigating odor perception in depression, including depressive states in healthy individuals and patient populations. Odor perception in depression has been assessed with psychophysical methods (olfactory sensitivity, odor identification, and discrimination), and odor ratings (intensity, emotional valence, familiarity). In addition, some studies investigated affective reactions to odors, and physiological and anatomical correlates of odor perception in depression. The summary reveals that MDD is associated with reduced olfactory sensitivity. However, odor identification and discrimination scores seem to be unaffected by depression. The reduced olfactory sensitivity might be associated with a reduced ability to encode olfactory information and a reduced volume of the olfactory bulb. While similar processes seem to occur in healthy individuals experiencing depressive states, they have not been observed in BPD or SAD patients. However, in order to conclude that the reduced olfactory sensitivity is directly linked to depression, it is suggested that studies should implement control measures of cognitive performances or perceptual abilities in other stimulus modalities. It is concluded that the reduced olfactory performance in MDD patients seems to be disorder-, modality-, and test-specific, and that the application of an appropriate olfactory and cognitive test-battery might be highly useful in the differential diagnosis of MDD. PMID:24570666

Basic emotions induced by odorants: a new approach based on autonomic pattern results.

PubMed

Vernet-Maury, E; Alaoui-Ismaïli, O; Dittmar, A; Delhomme, G; Chanel, J

1999-02-15

The aim of this study was to link the effects of odorants with the emotional process, through autonomic nervous system (ANS) responses. Taking Ekman's data and our previous results into account, we tried to verify a possible evocation by odorants of some basic emotions, i.e. anger, fear, sadness, surprise, disgust and happiness. The question investigated was: would it be possible to associate any of these emotions with a pattern of autonomic responses? A total of 15 subjects inhaled five odorants: lavender, ethyl aceto acetate, camphor, acetic acid and butyric acid acting as olfactory stimuli. After inhaling the odorant, subjects were requested to fill out an 11-point hedonic scale to rate its 'pleasantness' vs. 'unpleasantness'. ANS parameters monitored were skin potential and resistance, skin blood flow and temperature, instantaneous respiratory frequency and instantaneous heart rate. Simultaneous recording of these six autonomic parameters permitted the analysis of phasic responses through specific ANS patterns. An analysis of variance made it possible to differentiate among the five odorants. Two-by-two odorant comparisons for autonomic responses using Tukey's HSD multiple comparison test only permitted differentiation between 'pleasant' and 'unpleasant' odors. Camphor was differentiated from both types. For instance, long duration responses were associated with 'unpleasant' odors whereas camphor elicited intermediate responses. Taking into account each subject's preferential channel, it was possible to associate each ANS pattern with a basic emotion by means of a decision tree. The computation of subjects' responses made it possible to associate an odorant with a basic emotion, over the whole group: lavender elicited mostly 'happiness', as did, to a lesser degree ethyl aceto acetate; camphor induced either 'happiness', 'surprise' or 'sadness' according to subjects' past histories; butyric and acetic acids mainly induced negative emotions: 'anger' and 'disgust'. A high correlation was evidenced between subjects' hedonic evaluation and autonomic estimation of basic emotions. These results obtained from 15 subjects were compared to those observed in two similar experiments. These approaches showed comparable results. Thus, more than 60 subjects showed similar autonomic responses which can be transcribed into basic emotions. Thus, a multiparametric autonomic analysis allows the identification of the quality of the response, i.e. the type of basic emotion in addition to the intensity.

Sequential divergence and the multiplicative origin of community diversity

PubMed Central

Hood, Glen R.; Forbes, Andrew A.; Powell, Thomas H. Q.; Egan, Scott P.; Hamerlinck, Gabriela; Smith, James J.; Feder, Jeffrey L.

2015-01-01

Phenotypic and genetic variation in one species can influence the composition of interacting organisms within communities and across ecosystems. As a result, the divergence of one species may not be an isolated process, as the origin of one taxon could create new niche opportunities for other species to exploit, leading to the genesis of many new taxa in a process termed “sequential divergence.” Here, we test for such a multiplicative effect of sequential divergence in a community of host-specific parasitoid wasps, Diachasma alloeum, Utetes canaliculatus, and Diachasmimorpha mellea (Hymenoptera: Braconidae), that attack Rhagoletis pomonella fruit flies (Diptera: Tephritidae). Flies in the R. pomonella species complex radiated by sympatrically shifting and ecologically adapting to new host plants, the most recent example being the apple-infesting host race of R. pomonella formed via a host plant shift from hawthorn-infesting flies within the last 160 y. Using population genetics, field-based behavioral observations, host fruit odor discrimination assays, and analyses of life history timing, we show that the same host-related ecological selection pressures that differentially adapt and reproductively isolate Rhagoletis to their respective host plants (host-associated differences in the timing of adult eclosion, host fruit odor preference and avoidance behaviors, and mating site fidelity) cascade through the ecosystem and induce host-associated genetic divergence for each of the three members of the parasitoid community. Thus, divergent selection at lower trophic levels can potentially multiplicatively and rapidly amplify biodiversity at higher levels on an ecological time scale, which may sequentially contribute to the rich diversity of life. PMID:26499247

Autonomic nervous responses according to preference for the odor of jasmine tea.

PubMed

Inoue, Naohiko; Kuroda, Kyoko; Sugimoto, Akio; Kakuda, Takami; Fushiki, Tohru

2003-06-01

The effect of jasmine tea odor on the autonomic nervous system was investigated by a power spectral analysis of the heart rate variability. We assigned eight volunteers to two groups with either a predilection for or antipathy toward the jasmine tea odor. We tested both high- and low-intensity jasmine tea odors. The low-intensity odor was produced by diluting 20-fold the jasmine tea used for the high-intensity odor test. The low-intensity odor produced an increase in parasympathetic nervous activity in both the predilection and antipathy groups. The high-intensity odor produced an increase in parasympathetic nervous activity in the predilection group, but an increase in sympathetic nervous activity in the antipathy group. The odor of Chinese green tea, a basic ingredient of jasmine tea, produced no effects similar to those of the jasmine tea odor. These results suggest that the jasmine tea odor activated the parasympathetic nerve, whereas the higher-intensity odor activated the sympathetic nerve in those subjects who disliked the odor.

Comparison of Breastmilk Odor and Vanilla Odor on Mitigating Premature Infants' Response to Pain During and After Venipuncture.

PubMed

Jebreili, Mahnaz; Neshat, Hanieh; Seyyedrasouli, Aleheh; Ghojazade, Morteza; Hosseini, Mohammad Bagher; Hamishehkar, Hamed

2015-09-01

The main purpose of this study was to investigate the calming effects of breastmilk odor and vanilla odor on preterm infants during and after venipuncture. One hundred thirty-five preterm infants were randomly selected and divided into three groups: control, vanilla odor, and breastmilk odor. Infants in the breastmilk group were exposed to breastmilk odor, and infants in the vanilla group were exposed to vanilla odor from 5 minutes before the start of sampling until 30 seconds after sampling. The Premature Infant Pain Profile was used for calculating quality of pain in infants during and after sampling. Statistical analyses showed that both vanilla and breastmilk odors had calming effects on premature infants during sampling, but just breastmilk odor had calming effects on infants after the end of sampling. Compared with vanilla odor, breastmilk odor has more calming effects on premature infants. Breastmilk odor can be used for calming premature infants during and after venipuncture.

Neuropeptide Y enhances olfactory mucosa responses to odorant in hungry rats.

PubMed

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.

Influence of a municipal solid waste landfill in the surrounding environment: toxicological risk and odor nuisance effects.

PubMed

Palmiotto, Marinella; Fattore, Elena; Paiano, Viviana; Celeste, Giorgio; Colombo, Andrea; Davoli, Enrico

2014-07-01

The large amounts of treated waste materials and the complex biological and physicochemical processes make the areas in the proximity of landfills vulnerable not only to emissions of potential toxic compounds but also to nuisance such as odor pollution. All these factors have a dramatic impact in the local environment producing environmental quality degradation. Most of the human health problems come from the landfill gas, from its non-methanic volatile organic compounds and from hazardous air pollutants. In addition several odorants are released during landfill operations and uncontrolled emissions. In this work we present an integrated risk assessment for emissions of hazard compounds and odor nuisance, to describe environmental quality in the landfill proximity. The study was based on sampling campaigns to acquire emission data for polychlorinated dibenzo-p-dioxins and dibenzofurans, dioxin-like polychlorobiphenyls, polycyclic aromatic hydrocarbons, benzene and vinyl chloride monomer and odor. All concentration values in the emissions from the landfill were measured and used in an air dispersion model to estimate maximum concentrations and depositions in correspondence to five sensitive receptors located in proximity of the landfill. Results for the different scenarios and cancer and non-cancer effects always showed risk estimates which were orders of magnitude below those accepted from the main international agencies (WHO, US EPA). Odor pollution was significant for a limited downwind area near the landfill appearing to be a significant risk factor of the damage to the local environment. Copyright © 2014 Elsevier Ltd. All rights reserved.

Macroglomeruli for fruit odors change blend preference in Drosophila

NASA Astrophysics Data System (ADS)

Ibba, Irene; Angioy, Anna Maria; Hansson, Bill S.; Dekker, Teun

2010-12-01

The olfactory circuitry of Drosophila melanogaster is becoming increasingly clear. However, how olfactory processing translates into appropriate behavioral responses is still poorly understood. Using a sibling species approach, we tested how a perturbation in the olfactory circuitry affects odor preference. In a previous study, we found that the sibling species of D. melanogaster, the specialist D. sechellia, overrepresents a sensillum, ab3, the A neuron of which is sensitive to hexanoate esters, characteristic of the species' sole host, the Morinda citrifolia fruit. Concordantly, the corresponding glomerulus, DM2, is enlarged. In this study, we found that the ab3B neuron, the expansion of which was previously assumed to be pleiotropic and of no ecological significance, is in fact tuned to another morinda fruit volatile, 2-heptanone (HP). Axons of this neuron type arborize in a second enlarged glomerulus. In behavioral experiments we tested how this has affected the fly's odor preference. We demonstrate that D. sechellia has a reversed preference for the key ligands of these macroglomeruli, especially at high concentrations. Whereas D. melanogaster was repelled by high concentrations of these odors, D. sechellia was highly attracted. This was the case for odors presented singly, but more notably for blends thereof. Our study indicates that relatively simple changes, such as a shift in sensillar abundance, and concordant shifts in glomerular size, can distort the resulting olfactory code, and can lead to saltatory shifts in odor preference. D. sechellia has exploited this to align its olfactory preference with its ecological niche.

Presence of Ca2+-dependent K+ channels in chemosensory cilia support a role in odor transduction.

PubMed

Delgado, Ricardo; Saavedra, M Veronica; Schmachtenberg, Oliver; Sierralta, Jimena; Bacigalupo, Juan

2003-09-01

Olfactory receptor neurons (ORNs) respond to odorants with changes in the action potential firing rate. Excitatory responses, consisting of firing increases, are mediated by a cyclic AMP cascade that leads to the activation of cationic nonselective cyclic nucleotide-gated (CNG) channels and Ca2+-dependent Cl- (ClCa) channels. This process takes place in the olfactory cilia, where all protein components of this cascade are confined. ORNs from various vertebrate species have also been shown to generate inhibitory odor responses, expressed as decreases in action potential discharges. Odor inhibition appears to rely on Ca2+-dependent K+ (KCa) channels, but the underlying transduction mechanism remains unknown. If these channels are involved in odor transduction, they are expected to be present in the olfactory cilia. We found that a specific antibody against a large conductance KCa recognized a protein of approximately 116 kDa in Western blots of purified rat olfactory ciliary membranes. Moreover, the antibody labeled ORN cilia in isolated ORNs from rat and toad (Caudiverbera caudiverbera). In addition, single-channel recordings from inside-out membrane patches excised from toad chemosensory cilia showed the presence of 4 different types of KCa channels, with unitary conductances of 210, 60, 12, and 29 and 60 pS, high K+-selectivity, and Ca2+ sensitivities in the low micromolar range. Our work demonstrates the presence of K+ channels in the ORN cilia and supports their participation in odor transduction.

Co-Occurrence of Microcystins and Taste-and-Odor Compounds in Drinking Water Source and Their Removal in a Full-Scale Drinking Water Treatment Plant

PubMed Central

Feng, Muhua; Xu, Xiangen; Liu, Feifei; Ke, Fan; Li, Wenchao

2018-01-01

The co-occurrence of cyanotoxins and taste-and-odor compounds are a growing concern for drinking water treatment plants (DWTPs) suffering cyanobacteria in water resources. The dissolved and cell-bound forms of three microcystin (MC) congeners (MC-LR, MC-RR and MC-YR) and four taste-and-odor compounds (geosmin, 2-methyl isoborneol, β-cyclocitral and β-ionone) were investigated monthly from August 2011 to July 2012 in the eastern drinking water source of Lake Chaohu. The total concentrations of microcystins and taste-and-odor compounds reached 8.86 μg/L and 250.7 ng/L, respectively. The seasonal trends of microcystins were not consistent with those of the taste-and-odor compounds, which were accompanied by dominant species Microcystis and Dolichospermum. The fate of the cyanobacteria and metabolites were determined simultaneously after the processes of coagulation/flocculation, sedimentation, filtration and chlorination in the associated full-scale DWTP. The dissolved fractions with elevated concentrations were detected after some steps and the breakthrough of cyanobacteria and metabolites were even observed in finished water. Chlorophyll-a limits at intake were established for the drinking water source based on our investigation of multiple metabolites, seasonal variations and their elimination rates in the DWTP. Not only microcystins but also taste-and-odor compounds should be taken into account to guide the management in source water and in DWTPs. PMID:29301296

Co-Occurrence of Microcystins and Taste-and-Odor Compounds in Drinking Water Source and Their Removal in a Full-Scale Drinking Water Treatment Plant.

PubMed

Shang, Lixia; Feng, Muhua; Xu, Xiangen; Liu, Feifei; Ke, Fan; Li, Wenchao

2018-01-02

The co-occurrence of cyanotoxins and taste-and-odor compounds are a growing concern for drinking water treatment plants (DWTPs) suffering cyanobacteria in water resources. The dissolved and cell-bound forms of three microcystin (MC) congeners (MC-LR, MC-RR and MC-YR) and four taste-and-odor compounds (geosmin, 2-methyl isoborneol, β -cyclocitral and β -ionone) were investigated monthly from August 2011 to July 2012 in the eastern drinking water source of Lake Chaohu. The total concentrations of microcystins and taste-and-odor compounds reached 8.86 μg/L and 250.7 ng/L, respectively. The seasonal trends of microcystins were not consistent with those of the taste-and-odor compounds, which were accompanied by dominant species Microcystis and Dolichospermum . The fate of the cyanobacteria and metabolites were determined simultaneously after the processes of coagulation/flocculation, sedimentation, filtration and chlorination in the associated full-scale DWTP. The dissolved fractions with elevated concentrations were detected after some steps and the breakthrough of cyanobacteria and metabolites were even observed in finished water. Chlorophyll- a limits at intake were established for the drinking water source based on our investigation of multiple metabolites, seasonal variations and their elimination rates in the DWTP. Not only microcystins but also taste-and-odor compounds should be taken into account to guide the management in source water and in DWTPs.

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

The 2007 water crisis in Wuxi, China: analysis of the origin.

PubMed

Zhang, Xiao-jian; Chen, Chao; Ding, Jian-qing; Hou, Aixin; Li, Yong; Niu, Zhang-bin; Su, Xiao-yan; Xu, Yan-juan; Laws, Edward A

2010-10-15

An odorous tap water crisis that affected two million residents for several days occurred in Wuxi, China in the summer of 2007. Volatile sulfide chemicals including methyl thiols, dimethyl sulfide, dimethyl disulfide, and dimethyl trisulfide were the dominant odorous contaminants in Lake Taihu and in tap water during the crisis. These contaminants originated from the decomposition of a massive cyanobacterial bloom that was triggered by illegal industrial discharges and inadequately regulated domestic pollution. A specific emergency drinking water treatment process was quickly developed using a combination of potassium permanganate oxidation and powdered activated carbon adsorption. The emergency treatment process removed the odor from the tap water and solved the crisis successfully in several days. This experience underscores the suggestion that a combination of stresses associated with eutrophication and industrial and domestic wastewater discharges can push an aquatic system to the tipping point with consequences far more severe than would occur if the system were subjected to each stress separately. 2010 Elsevier B.V. All rights reserved.

Influence of Body Odors and Gender on Perceived Genital Arousal.

PubMed

Alves-Oliveira, Patrícia; Carvalho, Joana; Ferreira, Jacqueline; Alho, Laura; Nobre, Pedro; Olsson, Mats J; Soares, Sandra C

2018-04-01

Olfaction is often linked to mating behavior in nonhumans. Additionally, studies in mating behavior have shown that women seem to be more affected by odor cues than men. However, the relationship between odor cues and sexual response-specifically, sexual arousal-has not been studied yet. The aim of this study was to evaluate the impact of the exposure to human body odors (from individuals of the opposite gender) on perceived genital arousal, while these were presented concomitantly to sexually explicit video clips. Eighty university students (40 women) rated their perceived genital arousal (perceived degree of erection/genital lubrication) in response to an audiovisual sexual stimulus, while simultaneously exposed to a body odor from an opposite-gender donor or no odor. Participants also rated each odor sample's (body odor and no odor) perceived pleasantness, intensity, and familiarity. Findings indicated that odor condition had an effect on women's (but not men's) perceived genital arousal, with women showing higher levels of perceived genital arousal in the no odor condition. Also, results showed that women rated body odors as less pleasant than no odor. Notwithstanding, the odor ratings do not seem to explain the association between body odor and perceived genital arousal. The current results support the hypothesis that women, rather than men, are sensitive to odors in the context of sexual response. The findings of this study have relevance for the understanding of human sexuality with respect to chemosensory communication.

The relation between modeled odor exposure from livestock farming and odor annoyance among neighboring residents.

PubMed

Boers, D; Geelen, L; Erbrink, H; Smit, L A M; Heederik, D; Hooiveld, M; Yzermans, C J; Huijbregts, M; Wouters, I M

2016-04-01

Odor annoyance is an important environmental stressor for neighboring residents of livestock farms and may affect their quality of life and health. However, little is known about the relation between odor exposure due to livestock farming and odor annoyance. Even more, the relation between odor exposure and odor annoyance is rather complicated due to variable responses among individuals to comparable exposure levels and a large number of factors (such as age, gender, education) that may affect the relation. In this study, we (1) investigated the relation between modeled odor exposure and odor annoyance; (2) investigated whether other factors can affect this relation; and (3) compared our dose-response relation to a dose-response relation established in a previous study carried out in the Netherlands, more than 10 years ago, in order to investigate changes in odor perception and appreciation over time. We used data from 582 respondents who participated in a questionnaire survey among neighboring residents of livestock farms in the south of the Netherlands. Odor annoyance was established by two close-ended questions in a questionnaire; odor exposure was estimated using the Stacks dispersion model. The results of our study indicate a statistically significant and positive relation between modeled odor exposure and reported odor annoyance from livestock farming (OR 1.92; 95 % CI 1.53-2.41). Furthermore, age, asthma, education and perceived air pollution in the environment are all related to odor annoyance, although they hardly affect the relation between estimated livestock odor exposure and reported odor annoyance. We also found relatively more odor annoyance reported among neighboring residents than in a previous study conducted in the Netherlands. We found a strong relation between modeled odor exposure and odor annoyance. However, due to some uncertainties and small number of studies on this topic, further research and replication of results is recommended.

Development switch in neural circuitry underlying odor-malaise learning.

PubMed

Shionoya, Kiseko; Moriceau, Stephanie; Lunday, Lauren; Miner, Cathrine; Roth, Tania L; Sullivan, Regina M

2006-01-01

Fetal and infant rats can learn to avoid odors paired with illness before development of brain areas supporting this learning in adults, suggesting an alternate learning circuit. Here we begin to document the transition from the infant to adult neural circuit underlying odor-malaise avoidance learning using LiCl (0.3 M; 1% of body weight, ip) and a 30-min peppermint-odor exposure. Conditioning groups included: Paired odor-LiCl, Paired odor-LiCl-Nursing, LiCl, and odor-saline. Results showed that Paired LiCl-odor conditioning induced a learned odor aversion in postnatal day (PN) 7, 12, and 23 pups. Odor-LiCl Paired Nursing induced a learned odor preference in PN7 and PN12 pups but blocked learning in PN23 pups. 14C 2-deoxyglucose (2-DG) autoradiography indicated enhanced olfactory bulb activity in PN7 and PN12 pups with odor preference and avoidance learning. The odor aversion in weanling aged (PN23) pups resulted in enhanced amygdala activity in Paired odor-LiCl pups, but not if they were nursing. Thus, the neural circuit supporting malaise-induced aversions changes over development, indicating that similar infant and adult-learned behaviors may have distinct neural circuits.

Remote sensing of the energetic status of plants and ecosystems: optical and odorous signals

NASA Astrophysics Data System (ADS)

Penuelas, J.; Bartrons, M.; Llusia, J.; Filella, I.

2016-12-01

The optical and odorous signals emitted by plants and ecosystems present consistent relationships. They offer promising prospects for continuous local and global monitoring of the energetic status of plants and ecosystems, and therefore of their processing of energy and matter. We will discuss how the energetic status of plants (and ecosystems) resulting from the balance between the supply and demand of reducing power can be assessed biochemically, by the cellular NADPH/NADP ratio, optically, by using the photochemical reflectance index and sun-induced fluorescence as indicators of the dissipation of excess energy and associated physiological processes, and "odorously", by the emission of volatile organic compounds such as isoprenoids, as indicators of an excess of reducing equivalents and also of enhancement of protective converging physiological processes. These signals thus provide information on the energetic status, associated health status, and the functioning of plants and ecosystems. We will present the links among the three signals and will especially discuss the possibility of remotely sense the optical signals linked to carbon uptake and VOCs exchange by plants and ecosystems. These signals and their integration may have multiple applications for environmental and agricultural monitoring, for example, by extending the spatial coverage of carbon-flux and VOCs emission observations to most places and times, and/or for improving the process-based modeling of carbon fixation and isoprenoid emissions from terrestrial vegetation on plant, ecosystemic and global scales. Considerable challenges remain for a wide-scale and routine implementation of these biochemical, optical, and odorous signals for ecosystemic and/or agronomic monitoring and modeling, but its interest for making further steps forward in global ecology, agricultural applications, global carbon cycle, atmospheric science, and earth science warrants further research efforts in this line.

Positive relationship between odor identification and affective responses of negatively valenced odors

PubMed Central

Martinec Nováková, Lenka; Plotěná, Dagmar; Roberts, S. Craig; Havlíček, Jan

2015-01-01

Hedonic ratings of odors and olfactory preferences are influenced by a number of modulating factors, such as prior experience and knowledge about an odor’s identity. The present study addresses the relationship between knowledge about an odor’s identity due to prior experience, assessed by means of a test of cued odor identification, and odor pleasantness ratings in children who exhibit ongoing olfactory learning. Ninety-one children aged 8–11 years rated the pleasantness of odors in the Sniffin’ Sticks test and, subsequently, took the odor identification test. A positive association between odor identification and pleasantness was found for two unpleasant food odors (garlic and fish): higher pleasantness ratings were exhibited by those participants who correctly identified these odors compared to those who failed to correctly identify them. However, we did not find a similar effect for any of the more pleasant odors. The results of this study suggest that pleasantness ratings of some odors may be modulated by the knowledge of their identity due to prior experience and that this relationship might be more evident in unpleasant odors. PMID:26029143

Graded Encoding of Food Odor Value in the Drosophila Brain

PubMed Central

Beshel, Jennifer

2013-01-01

Odors are highly evocative, yet how and where in the brain odors derive meaning remains unknown. Our analysis of the Drosophila brain extends the role of a small number of hunger-sensing neurons to include food-odor value representation. In vivo two-photon calcium imaging shows the amplitude of food odor-evoked activity in neurons expressing Drosophila neuropeptide F (dNPF), the neuropeptide Y homolog, strongly correlates with food-odor attractiveness. Hunger elevates neural and behavioral responses to food odors only, although food odors that elicit attraction in the fed state also evoke heightened dNPF activity in fed flies. Inactivation of a subset of dNPF-expressing neurons or silencing dNPF receptors abolishes food-odor attractiveness, whereas genetically enhanced dNPF activity not only increases food-odor attractiveness but promotes attraction to aversive odors. Varying the amount of presented odor produces matching graded neural and behavioral curves, which can function to predict preference between odors. We thus demonstrate a possible motivationally scaled neural “value signal” accessible from uniquely identifiable cells. PMID:24089477

Cell-Based Odorant Sensor Array for Odor Discrimination Based on Insect Odorant Receptors.

PubMed

Termtanasombat, Maneerat; Mitsuno, Hidefumi; Misawa, Nobuo; Yamahira, Shinya; Sakurai, Takeshi; Yamaguchi, Satoshi; Nagamune, Teruyuki; Kanzaki, Ryohei

2016-07-01

The olfactory system of living organisms can accurately discriminate numerous odors by recognizing the pattern of activation of several odorant receptors (ORs). Thus, development of an odorant sensor array based on multiple ORs presents the possibility of mimicking biological odor discrimination mechanisms. Recently, we developed novel odorant sensor elements with high sensitivity and selectivity based on insect OR-expressing Sf21 cells that respond to target odorants by displaying increased fluorescence intensity. Here we introduce the development of an odorant sensor array composed of several Sf21 cell lines expressing different ORs. In this study, an array pattern of four cell lines expressing Or13a, Or56a, BmOR1, and BmOR3 was successfully created using a patterned polydimethylsiloxane film template and cell-immobilizing reagents, termed biocompatible anchor for membrane (BAM). We demonstrated that BAM could create a clear pattern of Sf21 sensor cells without impacting their odorant-sensing performance. Our sensor array showed odorant-specific response patterns toward both odorant mixtures and single odorant stimuli, allowing us to visualize the presence of 1-octen-3-ol, geosmin, bombykol, and bombykal as an increased fluorescence intensity in the region of Or13a, Or56a, BmOR1, and BmOR3 cell lines, respectively. Therefore, we successfully developed a new methodology for creating a cell-based odorant sensor array that enables us to discriminate multiple target odorants. Our method might be expanded into the development of an odorant sensor capable of detecting a large range of environmental odorants that might become a promising tool used in various applications including the study of insect semiochemicals and food contamination.

Early Parkinson's disease patients on rasagiline present with better odor discrimination.

PubMed

Haehner, Antje; Habersack, Angela; Wienecke, Miriam; Storch, Alexander; Reichmann, Heinz; Hummel, Thomas

2015-11-01

The effects of rasagiline on olfaction in animal studies are convincing. However, apart from various anecdotal patient reports, they could not be reproduced in prospective studies in humans. Cross-sectional data of large patient groups are still missing. The aim of this study was therefore to determine the olfactory function in a broad heterogeneous Parkinson's disease (PD) population with and without rasagiline intake. In this single-center, cross-sectional study 224 PD patients with and without rasagiline (1 mg/day) participated. Seventy-four of them received rasagiline as mono, or adjunct therapy. One-hundred fifty patients were untreated or received PD medication other than rasagiline. Comprehensive olfactory testing was performed for phenyl-ethyl alcohol odor thresholds, odor discrimination, and odor identification. Olfactory function did not differ between the two treatment groups with disease duration up to 29 years. Rasagiline-treated patients with disease duration of less than 8 years, however, presented with significant better odor discrimination abilities compared to PD patients without rasagiline treatment. This effect was no longer evident in patients with longer disease duration and proofed to be independent of age, sex, and medication. Our results may suggest that rasagiline treatment has a positive effect on the processing of olfactory information in early PD.

Neurons in the barrel cortex turn into processing whisker and odor signals: a cellular mechanism for the storage and retrieval of associative signals

PubMed Central

Wang, Dangui; Zhao, Jun; Gao, Zilong; Chen, Na; Wen, Bo; Lu, Wei; Lei, Zhuofan; Chen, Changfeng; Liu, Yahui; Feng, Jing; Wang, Jin-Hui

2015-01-01

Associative learning and memory are essential to logical thinking and cognition. How the neurons are recruited as associative memory cells to encode multiple input signals for their associated storage and distinguishable retrieval remains unclear. We studied this issue in the barrel cortex by in vivo two-photon calcium imaging, electrophysiology, and neural tracing in our mouse model that the simultaneous whisker and olfaction stimulations led to odorant-induced whisker motion. After this cross-modal reflex arose, the barrel and piriform cortices connected. More than 40% of barrel cortical neurons became to encode odor signal alongside whisker signal. Some of these neurons expressed distinct activity patterns in response to acquired odor signal and innate whisker signal, and others encoded similar pattern in response to these signals. In the meantime, certain barrel cortical astrocytes encoded odorant and whisker signals. After associative learning, the neurons and astrocytes in the sensory cortices are able to store the newly learnt signal (cross-modal memory) besides the innate signal (native-modal memory). Such associative memory cells distinguish the differences of these signals by programming different codes and signify the historical associations of these signals by similar codes in information retrievals. PMID:26347609

Identification of Ginger (Zingiber officinale Roscoe) Volatiles and Localization of Aroma-Active Constituents by GC-Olfactometry.

PubMed

Pang, Xueli; Cao, Jianmin; Wang, Dabin; Qiu, Jun; Kong, Fanyu

2017-05-24

For the characterization of chemical components contributing to the aroma of ginger, which could benefit the development of deep-processed ginger products, volatile extracts were isolated by a combination of direct solvent extraction-solvent-assisted flavor evaporation and static headspace analysis. Aroma-impact components were identified by gas chromatography-olfactometry-mass spectrometry, and the most potent odorants were further screened by aroma extract dilution analysis (AEDA) and static headspace dilution analysis (SHDA). The AEDA results revealed that geranial, eucalyptol, β-linalool, and bornyl acetate were the most potent odorants, exhibiting the highest flavor dilution factor (FD factor) of 2187. SHDA indicated that the predominant headspace odorants were α-pinene and eucalyptol. In addition, odorants exhibiting a high FD factor in SHDA were estimated to be potent aroma contributors in AEDA. The predominant odorants were found to be monoterpenes and sesquiterpenes, as along with their oxygenated derivatives, providing minty, lemon-like, herbal, and woody aromas. On the other hand, three highly volatile compounds detected by SHDA were not detected by AEDA, whereas 34 high-polarity, low-volatility compounds were identified only by AEDA, demonstrating the complementary natures of SHDA and AEDA and the necessity of utilizing both techniques to accurately characterize the aroma of ginger.

Combinatorial effects of odorants on mouse behavior

PubMed Central

Saraiva, Luis R.; Kondoh, Kunio; Ye, Xiaolan; Yoon, Kyoung-hye; Hernandez, Marcus; Buck, Linda B.

2016-01-01

The mechanisms by which odors induce instinctive behaviors are largely unknown. Odor detection in the mouse nose is mediated by >1, 000 different odorant receptors (ORs) and trace amine-associated receptors (TAARs). Odor perceptions are encoded combinatorially by ORs and can be altered by slight changes in the combination of activated receptors. However, the stereotyped nature of instinctive odor responses suggests the involvement of specific receptors and genetically programmed neural circuits relatively immune to extraneous odor stimuli and receptor inputs. Here, we report that, contrary to expectation, innate odor-induced behaviors can be context-dependent. First, different ligands for a given TAAR can vary in behavioral effect. Second, when combined, some attractive and aversive odorants neutralize one another’s behavioral effects. Both a TAAR ligand and a common odorant block aversion to a predator odor, indicating that this ability is not unique to TAARs and can extend to an aversive response of potential importance to survival. In vitro testing of single receptors with binary odorant mixtures indicates that behavioral blocking can occur without receptor antagonism in the nose. Moreover, genetic ablation of a single receptor prevents its cognate ligand from blocking predator odor aversion, indicating that the blocking requires sensory input from the receptor. Together, these findings indicate that innate odor-induced behaviors can depend on context, that signals from a single receptor can block innate odor aversion, and that instinctive behavioral responses to odors can be modulated by interactions in the brain among signals derived from different receptors. PMID:27208093

Synapsin Determines Memory Strength after Punishment- and Relief-Learning

PubMed Central

Niewalda, Thomas; Michels, Birgit; Jungnickel, Roswitha; Diegelmann, Sören; Kleber, Jörg; Kähne, Thilo

2015-01-01

Adverse life events can induce two kinds of memory with opposite valence, dependent on timing: “negative” memories for stimuli preceding them and “positive” memories for stimuli experienced at the moment of “relief.” Such punishment memory and relief memory are found in insects, rats, and man. For example, fruit flies (Drosophila melanogaster) avoid an odor after odor-shock training (“forward conditioning” of the odor), whereas after shock-odor training (“backward conditioning” of the odor) they approach it. Do these timing-dependent associative processes share molecular determinants? We focus on the role of Synapsin, a conserved presynaptic phosphoprotein regulating the balance between the reserve pool and the readily releasable pool of synaptic vesicles. We find that a lack of Synapsin leaves task-relevant sensory and motor faculties unaffected. In contrast, both punishment memory and relief memory scores are reduced. These defects reflect a true lessening of associative memory strength, as distortions in nonassociative processing (e.g., susceptibility to handling, adaptation, habituation, sensitization), discrimination ability, and changes in the time course of coincidence detection can be ruled out as alternative explanations. Reductions in punishment- and relief-memory strength are also observed upon an RNAi-mediated knock-down of Synapsin, and are rescued both by acutely restoring Synapsin and by locally restoring it in the mushroom bodies of mutant flies. Thus, both punishment memory and relief memory require the Synapsin protein and in this sense share genetic and molecular determinants. We note that corresponding molecular commonalities between punishment memory and relief memory in humans would constrain pharmacological attempts to selectively interfere with excessive associative punishment memories, e.g., after traumatic experiences. PMID:25972175

In vivo electrophysiological recordings in amygdala subnuclei reveal selective and distinct responses to a behaviorally identified predator odor.

PubMed

Govic, Antonina; Paolini, Antonio G

2015-03-01

Chemosensory cues signaling predators reliably stimulate innate defensive responses in rodents. Despite the well-documented role of the amygdala in predator odor-induced fear, evidence for the relative contribution of the specific nuclei that comprise this structurally heterogeneous structure is conflicting. In an effort to clarify this we examined neural activity, via electrophysiological recordings, in amygdala subnuclei to controlled and repeated presentations of a predator odor: cat urine. Defensive behaviors, characterized by avoidance, decreased exploration, and increased risk assessment, were observed in adult male hooded Wistar rats (n = 11) exposed to a cloth impregnated with cat urine. Electrophysiological recordings of the amygdala (777 multiunit clusters) were subsequently obtained in freely breathing anesthetized rats exposed to cat urine, distilled water, and eugenol via an air-dilution olfactometer. Recorded units selectively responded to cat urine, and frequencies of responses were distributed differently across amygdala nuclei; medial amygdala (MeA) demonstrated the greatest frequency of responses to cat urine (51.7%), followed by the basolateral and basomedial nuclei (18.8%) and finally the central amygdala (3.0%). Temporally, information transduction occurred primarily from the cortical amygdala and MeA (ventral divisions) to other amygdala nuclei. Interestingly, MeA subnuclei exhibited distinct firing patterns to predator urine, potentially revealing aspects of the underlying neurocircuitry of predator odor processing and defensiveness. These findings highlight the critical involvement of the MeA in processing olfactory cues signaling predator threat and converge with previous studies to indicate that amygdala regulation of predator odor-induced fear is restricted to a particular set of subnuclei that primarily include the MeA, particularly the ventral divisions. Copyright © 2015 the American Physiological Society.

A pharmacological profile of the aldehyde receptor repertoire in rat olfactory epithelium

PubMed Central

Araneda, Ricardo C; Peterlin, Zita; Zhang, Xinmin; Chesler, Alex; Firestein, Stuart

2004-01-01

Several lines of evidence suggest that odorants are recognized through a combinatorial process in the olfactory system; a single odorant is recognized by multiple receptors and multiple odorants are recognized by the same receptor. However few details of how this might actually function for any particular odour set or receptor family are available. Approaching the problem from the ligands rather than the receptors, we used the response to a common odorant, octanal, as the basis for defining multiple receptor profiles. Octanal and other aldehydes induce large EOG responses in the rodent olfactory epithelium, suggesting that these compounds activate a large number of odour receptors (ORs). Here, we have determined and compared the pharmacological profile of different octanal receptors using Ca2+ imaging in isolated olfactory sensory neurones (OSNs). It is believed that each OSN expresses only one receptor, thus the response profile of each cell corresponds to the pharmacological profile of one particular receptor. We stimulated the cells with a panel of nine odorants, which included octanal, octanoic acid, octanol and cinnamaldehyde among others (all at 30μm). Cluster analysis revealed several distinct pharmacological profiles for cells that were all sensitive to octanal. Some receptors had a broad molecular range, while others were activated only by octanal. Comparison of the profiles with that of the one identified octanal receptor, OR-I7, indicated several differences. While OR-I7 is activated by low concentrations of octanal and blocked by citral, other receptors were less sensitive to octanal and not blocked by citral. A lower estimate for the maximal number of octanal receptors is between 33 and 55. This large number of receptors for octanal suggests that, although the peripheral olfactory system is endowed with high sensitivity, discrimination among different compounds probably requires further central processing. PMID:14724183

Synapsin determines memory strength after punishment- and relief-learning.

PubMed

Niewalda, Thomas; Michels, Birgit; Jungnickel, Roswitha; Diegelmann, Sören; Kleber, Jörg; Kähne, Thilo; Gerber, Bertram

2015-05-13

Adverse life events can induce two kinds of memory with opposite valence, dependent on timing: "negative" memories for stimuli preceding them and "positive" memories for stimuli experienced at the moment of "relief." Such punishment memory and relief memory are found in insects, rats, and man. For example, fruit flies (Drosophila melanogaster) avoid an odor after odor-shock training ("forward conditioning" of the odor), whereas after shock-odor training ("backward conditioning" of the odor) they approach it. Do these timing-dependent associative processes share molecular determinants? We focus on the role of Synapsin, a conserved presynaptic phosphoprotein regulating the balance between the reserve pool and the readily releasable pool of synaptic vesicles. We find that a lack of Synapsin leaves task-relevant sensory and motor faculties unaffected. In contrast, both punishment memory and relief memory scores are reduced. These defects reflect a true lessening of associative memory strength, as distortions in nonassociative processing (e.g., susceptibility to handling, adaptation, habituation, sensitization), discrimination ability, and changes in the time course of coincidence detection can be ruled out as alternative explanations. Reductions in punishment- and relief-memory strength are also observed upon an RNAi-mediated knock-down of Synapsin, and are rescued both by acutely restoring Synapsin and by locally restoring it in the mushroom bodies of mutant flies. Thus, both punishment memory and relief memory require the Synapsin protein and in this sense share genetic and molecular determinants. We note that corresponding molecular commonalities between punishment memory and relief memory in humans would constrain pharmacological attempts to selectively interfere with excessive associative punishment memories, e.g., after traumatic experiences. Copyright © 2015 Niewalda et al.

Novel cell-based odorant sensor elements based on insect odorant receptors.

PubMed

Mitsuno, Hidefumi; Sakurai, Takeshi; Namiki, Shigehiro; Mitsuhashi, Hiroyuki; Kanzaki, Ryohei

2015-03-15

Development of cell-based odorant sensor elements combined not only high degree of sensitivity and selectivity but also long-term stability is crucial for their practical applications. Here we report the development of a novel cell-based odorant sensor element that sensitively and selectively detects odorants and displays increased fluorescent intensities over a long period of time. Our odorant sensor elements, based on Sf21 cell lines expressing insect odorant receptors, are sensitive to the level of several tens of parts per billion in solution, can selectively distinguish between different types of odorants based on the odorant selectivity intrinsic to the expressed receptors, and have response times of approximately 13s. Specifically, with the use of Sf21 cells and insect odorant receptors, we demonstrated that the established cell lines stably expressing insect odorant receptors are able to detect odorants with consistent responsiveness for at least 2 months, thus exceeding the short life-span normally associated with cell-based sensors. We also demonstrated the development of a compact odorant sensor chip by integrating the established insect cell lines into a microfluidic chip. The methodology we established in this study, in conjunction with the large repertoire of insect odorant receptors, will aid in the development of practical cell-based odorant sensors for various applications, including food administration and health management. Copyright © 2014 Elsevier B.V. All rights reserved.

77 FR 22381 - Odorant Fade in Railroad Tank Cars

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-13

... can lead to the loss of odorant. 4. Facilities that load odorized LPG into tank cars take any other... diminished levels of odorant or no odorant present, represents significant safety risks. Absent sufficient... the LPG in the storage tanks at the construction site had virtually no odorant present, explaining why...

Odor and odorous chemical emissions from animal buildings: part 1 - project overview, collection methods, and quality control

USDA-ARS?s Scientific Manuscript database

Livestock facilities have historically generated public concerns due to their emissions of odorous air and various chemical pollutants. Odor emission factors and identification of principal odorous chemicals are needed to better understand the problem. Applications of odor emission factors include i...

Ontogeny of Odor-LiCl vs. Odor-Shock Learning: Similar Behaviors but Divergent Ages of Functional Amygdala Emergence

ERIC Educational Resources Information Center

Raineki, Charlis; Shionoya, Kiseko; Sander, Kristin; Sullivan, Regina M.

2009-01-01

Both odor-preference and odor-aversion learning occur in perinatal pups before the maturation of brain structures that support this learning in adults. To characterize the development of odor learning, we compared three learning paradigms: (1) odor-LiCl (0.3M; 1% body weight, ip) and (2) odor-1.2-mA shock (hindlimb, 1sec)--both of which…

Factors affecting the water odor caused by chloramines during drinking water disinfection.

PubMed

Wang, An-Qi; Lin, Yi-Li; Xu, Bin; Hu, Chen-Yan; Gao, Ze-Chen; Liu, Zhi; Cao, Tong-Cheng; Gao, Nai-Yun

2018-10-15

Chloramine disinfection is one of the most common disinfection methods in drinking water treatment. In this study, the temporal variability of water odors during monochloramine auto-decomposition was investigated to elucidate the characteristics of odor problems caused by adopting chloramine disinfection in tap water. Odor intensities and dominant odorant contributions were determined using the flavor profile analysis (FPA) and odor active value (OAV), respectively. During auto-decomposition of monochloramine, Cl 2 /N molar ratio, pH, temperature, and the presence of NOM all affected odor intensity and odor temporal variation in drinking water. In general, decreasing pH from 8.5 to 6.0 led to increasing perceived odor intensity due to the formation of dichloramine. The major odorants responsible for chlorinous odor under acidic and non-acidic conditions were dichloramine and monochloramine, respectively. Chloraminated water with a Cl 2 /N molar ratio of 0.6 or NOM concentration <2 mg-C L -1 inhibited odor intensity. Furthermore, the influence of rechlorination on chlorinous odor intensity for chloraminated water should not be neglected. The results of this study will be beneficial for the control of chlorinous odors caused by chloramine disinfection in drinking water. Copyright © 2018 Elsevier B.V. All rights reserved.

Determination of urine-derived odorous compounds in a source separation sanitation system.

PubMed

Liu, Bianxia; Giannis, Apostolos; Chen, Ailu; Zhang, Jiefeng; Chang, Victor W C; Wang, Jing-Yuan

2017-02-01

Source separation sanitation systems have attracted more and more attention recently. However, separate urine collection and treatment could induce odor issues, especially in large scale application. In order to avoid such issues, it is necessary to monitor the odor related compounds that might be generated during urine storage. This study investigated the odorous compounds that emitted from source-separated human urine under different hydrolysis conditions. Batch experiments were conducted to investigate the effect of temperature, stale/fresh urine ratio and urine dilution on odor emissions. It was found that ammonia, dimethyl disulfide, allyl methyl sulfide and 4-heptanone were the main odorous compounds generated from human urine, with headspace concentrations hundreds of times higher than their respective odor thresholds. Furthermore, the high temperature accelerated urine hydrolysis and liquid-gas mass transfer, resulting a remarkable increase of odor emissions from the urine solution. The addition of stale urine enhanced urine hydrolysis and expedited odor emissions. On the contrary, diluted urine emitted less odorous compounds ascribed to reduced concentrations of odorant precursors. In addition, this study quantified the odor emissions and revealed the constraints of urine source separation in real-world applications. To address the odor issue, several control strategies are recommended for odor mitigation or elimination from an engineering perspective. Copyright © 2016. Published by Elsevier B.V.

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

PubMed Central

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

2016-01-01

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

Individually identifiable body odors are produced by the gorilla and discriminated by humans.

PubMed

Hepper, Peter G; Wells, Deborah L

2010-05-01

Many species produce odor cues that enable them to be identified individually, as well as providing other socially relevant information. Study of the role of odor cues in the social behavior of great apes is noticeable by its absence. Olfaction has been viewed as having little role in guiding behavior in these species. This study examined whether Western lowland gorillas produce an individually identifiable odor. Odor samples were obtained by placing cloths in the gorilla's den. A delayed matching to sample task was used with human participants (n = 100) to see if they were able to correctly match a target odor sample to a choice of either: 2 odors (the target sample and another, Experiment 1) and 6 odors (the target sample and 5 others, Experiment 2). Participants were correctly able to identify the target odor when given either 2 or 6 matches. Subjects made fewest errors when matching the odor of the silverback, whereas matching the odors of the young gorillas produced most errors. The results indicate that gorillas do produce individually identifiable body odors and introduce the possibility that odor cues may play a role in gorilla social behavior.

Multiple functions of GABA A and GABA B receptors during pattern processing in the zebrafish olfactory bulb.

PubMed

Tabor, Rico; Yaksi, Emre; Friedrich, Rainer W

2008-07-01

gamma-Aminobutyric acid (GABA)ergic synapses are thought to play pivotal roles in the processing of activity patterns in the olfactory bulb (OB), but their functions have been difficult to study during odor responses in the intact system. We pharmacologically manipulated GABA(A) and GABA(B) receptors in the OB of zebrafish and analysed the effects on odor responses of the output neurons, the mitral cells (MCs), by electrophysiological recordings and temporally deconvolved two-photon Ca2+ imaging. The blockade of GABA(B) receptors enhanced presynaptic Ca2+ influx into afferent axon terminals, and changed the amplitude and time course of a subset of MC responses, indicating that GABA(B) receptors have a modulatory influence on OB output activity. The blockade of GABA(A) receptors induced epileptiform firing, enhanced excitatory responses and abolished fast oscillations in the local field potential. Moreover, the topological reorganization and decorrelation of MC activity patterns during the initial phase of the response was perturbed. These results indicate that GABA(A) receptor-containing circuits participate in the balance of excitation and inhibition, the regulation of total OB output activity, the synchronization of odor-dependent neuronal ensembles, and the reorganization of odor-encoding activity patterns. GABA(A) and GABA(B) receptors are therefore differentially involved in multiple functions of neuronal circuits in the OB.

Reward for food odors: an fMRI study of liking and wanting as a function of metabolic state and BMI.

PubMed

Jiang, Tao; Soussignan, Robert; Schaal, Benoist; Royet, Jean-Pierre

2015-04-01

Brain reward systems mediate liking and wanting for food reward. Here, we explore the differential involvement of the following structures for these two components: the ventral and dorsal striatopallidal area, orbitofrontal cortex (OFC), anterior insula and anterior cingulate. Twelve healthy female participants were asked to rate pleasantness (liking of food and non-food odors) and the desire to eat (wanting of odor-evoked food) during event-related functional magnetic resonance imaging (fMRI). The subjective ratings and fMRI were performed in hunger and satiety states. Activations of regions of interest were compared as a function of task (liking vs wanting), odor category (food vs non-food) and metabolic state (hunger vs satiety). We found that the nucleus accumbens and ventral pallidum were differentially involved in liking or wanting during the hunger state, which suggests a reciprocal inhibitory influence between these structures. Neural activation of OFC subregions was correlated with either liking or wanting ratings, suggesting an OFC role in reward processing magnitude. Finally, during the hunger state, participants with a high body mass index exhibited less activation in neural structures underlying food reward processing. Our results suggest that food liking and wanting are two separable psychological constructs and may be functionally segregated within the cortico-striatopallidal circuit. © The Author (2014). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

Advanced oxidation technology for H2S odor gas using non-thermal plasma

NASA Astrophysics Data System (ADS)

Tao, ZHU; Ruonan, WANG; Wenjing, BIAN; Yang, CHEN; Weidong, JING

2018-05-01

Non-thermal plasma technology is a new type of odor treatment processing. We deal with H2S from waste gas emission using non-thermal plasma generated by dielectric barrier discharge. On the basis of two criteria, removal efficiency and absolute removal amount, we deeply investigate the changes in electrical parameters and process parameters, and the reaction process of the influence of ozone on H2S gas removal. The experimental results show that H2S removal efficiency is proportional to the voltage, frequency, power, residence time and energy efficiency, while it is inversely proportional to the initial concentration of H2S gas, and ozone concentration. This study lays the foundations of non-thermal plasma technology for further commercial application.

Odor and odorous chemical emissions from animal buildings: Part 3 - chemical emissions

USDA-ARS?s Scientific Manuscript database

This study was an add-on study to the National Air Emission Monitoring Study (NAEMS). The objective of this study was to measure odor emissions and corresponding concentrations and emissions of target odorous gases. Odor and odorous gas measurements at four NAEMS sites (dairy barns in Wisconsin-WI5B...

Odor and odorous chemical emissions from animal buildings: Part 3. Chemical emissions

USDA-ARS?s Scientific Manuscript database

The objective of this study was to measure the long-term odor emissions and corresponding concentrations and emissions of 20 odorous volatile organic compounds (VOCs). This study was an add-on study to the National Air Emission Monitoring Study (NAEMS). Odor and odorous gas measurements at four NAEM...

Odor and chemical emissions from dairy and swine facilities: Part 1 - project overview and collection methods

USDA-ARS?s Scientific Manuscript database

Livestock facilities have received numerous criticisms due to their emissions of odorous air and chemicals. Hence, there is a significant need for odor emission factors and identification of principle odorous chemicals. Odor emission factors are used as inputs to odor setback models, while chemica...

The effect of meat consumption on body odor attractiveness.

PubMed

Havlicek, Jan; Lenochova, Pavlina

2006-10-01

Axillary body odor is individually specific and potentially a rich source of information about its producer. Odor individuality partly results from genetic individuality, but the influence of ecological factors such as eating habits are another main source of odor variability. However, we know very little about how particular dietary components shape our body odor. Here we tested the effect of red meat consumption on body odor attractiveness. We used a balanced within-subject experimental design. Seventeen male odor donors were on "meat" or "nonmeat" diet for 2 weeks wearing axillary pads to collect body odor during the final 24 h of the diet. Fresh odor samples were assessed for their pleasantness, attractiveness, masculinity, and intensity by 30 women not using hormonal contraceptives. We repeated the same procedure a month later with the same odor donors, each on the opposite diet than before. Results of repeated measures analysis of variance showed that the odor of donors when on the nonmeat diet was judged as significantly more attractive, more pleasant, and less intense. This suggests that red meat consumption has a negative impact on perceived body odor hedonicity.

Functional identification and reconstitution of an odorant receptor in single olfactory neurons

PubMed Central

Touhara, Kazushige; Sengoku, Shintaro; Inaki, Koichiro; Tsuboi, Akio; Hirono, Junzo; Sato, Takaaki; Sakano, Hitoshi; Haga, Tatsuya

1999-01-01

The olfactory system is remarkable in its capacity to discriminate a wide range of odorants through a series of transduction events initiated in olfactory receptor neurons. Each olfactory neuron is expected to express only a single odorant receptor gene that belongs to the G protein coupled receptor family. The ligand–receptor interaction, however, has not been clearly characterized. This study demonstrates the functional identification of olfactory receptor(s) for specific odorant(s) from single olfactory neurons by a combination of Ca2+-imaging and reverse transcription–coupled PCR analysis. First, a candidate odorant receptor was cloned from a single tissue-printed olfactory neuron that displayed odorant-induced Ca2+ increase. Next, recombinant adenovirus-mediated expression of the isolated receptor gene was established in the olfactory epithelium by using green fluorescent protein as a marker. The infected neurons elicited external Ca2+ entry when exposed to the odorant that originally was used to identify the receptor gene. Experiments performed to determine ligand specificity revealed that the odorant receptor recognized specific structural motifs within odorant molecules. The odorant receptor-mediated signal transduction appears to be reconstituted by this two-step approach: the receptor screening for given odorant(s) from single neurons and the functional expression of the receptor via recombinant adenovirus. The present approach should enable us to examine not only ligand specificity of an odorant receptor but also receptor specificity and diversity for a particular odorant of interest. PMID:10097159

Odor Profile of Different Varieties of Extra-Virgin Olive Oil During Deep Frying Using an Electronic Nose and SPME-GC-FID

NASA Astrophysics Data System (ADS)

Messina, Valeria; Biolatto, Andrea; Sancho, Ana; Descalzo, Adriana; Grigioni, Gabriela; de Reca, Noemí Walsöe

2011-09-01

The aim of the performed work was to evaluate with an electronic nose changes in odor profile of Arauco and Arbequina varieties of extra-virgin olive oil during deep-frying. Changes in odor were analyzed using an electronic nose composed of 16 sensors. Volatile compounds were analyzed by SPME-GC-FID. Principal Component Analysis was applied for electronic results. Arauco variety showed the highest response for sensors. Statistical analysis for volatile compounds indicated a significant (P<0.001) interaction between variety and time of frying processes. Arauco variety showed the highest production of volatile compounds at 60 min of deep frying. The two varieties presented distinct patterns of volatile products, being clearly identified with the electronic nose.

Behavioral responses to mammalian blood odor and a blood odor component in four species of large carnivores.

PubMed

Nilsson, Sara; Sjöberg, Johanna; Amundin, Mats; Hartmann, Constanze; Buettner, Andrea; Laska, Matthias

2014-01-01

Only little is known about whether single volatile compounds are as efficient in eliciting behavioral responses in animals as the whole complex mixture of a behaviorally relevant odor. Recent studies analysing the composition of volatiles in mammalian blood, an important prey-associated odor stimulus for predators, found the odorant trans-4,5-epoxy-(E)-2-decenal to evoke a typical "metallic, blood-like" odor quality in humans. We therefore assessed the behavior of captive Asian wild dogs (Cuon alpinus), African wild dogs (Lycaon pictus), South American bush dogs (Speothos venaticus), and Siberian tigers (Panthera tigris altaica) when presented with wooden logs that were impregnated either with mammalian blood or with the blood odor component trans-4,5-epoxy-(E)-2-decenal, and compared it to their behavior towards a fruity odor (iso-pentyl acetate) and a near-odorless solvent (diethyl phthalate) as control. We found that all four species displayed significantly more interactions with the odorized wooden logs such as sniffing, licking, biting, pawing, and toying, when they were impregnated with the two prey-associated odors compared to the two non-prey-associated odors. Most importantly, no significant differences were found in the number of interactions with the wooden logs impregnated with mammalian blood and the blood odor component in any of the four species. Only one of the four species, the South American bush dogs, displayed a significant decrease in the number of interactions with the odorized logs across the five sessions performed per odor stimulus. Taken together, the results demonstrate that a single blood odor component can be as efficient in eliciting behavioral responses in large carnivores as the odor of real blood, suggesting that trans-4,5-epoxy-(E)-2-decenal may be perceived by predators as a "character impact compound" of mammalian blood odor. Further, the results suggest that odorized wooden logs are a suitable manner of environmental enrichment for captive carnivores.

Psychology of Fragrance Use: Perception of Individual Odor and Perfume Blends Reveals a Mechanism for Idiosyncratic Effects on Fragrance Choice

PubMed Central

Lenochová, Pavlína; Vohnoutová, Pavla; Roberts, S. Craig; Oberzaucher, Elisabeth; Grammer, Karl; Havlíček, Jan

2012-01-01

Cross-culturally, fragrances are used to modulate body odor, but the psychology of fragrance choice has been largely overlooked. The prevalent view is that fragrances mask an individual's body odor and improve its pleasantness. In two experiments, we found positive effects of perfume on body odor perception. Importantly, however, this was modulated by significant interactions with individual odor donors. Fragrances thus appear to interact with body odor, creating an individually-specific odor mixture. In a third experiment, the odor mixture of an individual's body odor and their preferred perfume was perceived as more pleasant than a blend of the same body odor with a randomly-allocated perfume, even when there was no difference in pleasantness between the perfumes. This indicates that fragrance use extends beyond simple masking effects and that people choose perfumes that interact well with their own odor. Our results provide an explanation for the highly individual nature of perfume choice. PMID:22470479

Psychology of fragrance use: perception of individual odor and perfume blends reveals a mechanism for idiosyncratic effects on fragrance choice.

PubMed

Lenochová, Pavlína; Vohnoutová, Pavla; Roberts, S Craig; Oberzaucher, Elisabeth; Grammer, Karl; Havlíček, Jan

2012-01-01

Cross-culturally, fragrances are used to modulate body odor, but the psychology of fragrance choice has been largely overlooked. The prevalent view is that fragrances mask an individual's body odor and improve its pleasantness. In two experiments, we found positive effects of perfume on body odor perception. Importantly, however, this was modulated by significant interactions with individual odor donors. Fragrances thus appear to interact with body odor, creating an individually-specific odor mixture. In a third experiment, the odor mixture of an individual's body odor and their preferred perfume was perceived as more pleasant than a blend of the same body odor with a randomly-allocated perfume, even when there was no difference in pleasantness between the perfumes. This indicates that fragrance use extends beyond simple masking effects and that people choose perfumes that interact well with their own odor. Our results provide an explanation for the highly individual nature of perfume choice.

Addition of Olfactory Stimuli to Virtual Reality Simulations for Medical Training Applications

DTIC Science & Technology

1996-11-01

surveyed and a working set of odorants were indentified or developed in sufficient quantities to support further testing. Extensive studies were performed...Olfactory Displays for HMD Systems 8 Ambulatory Olfactory HMD Display 11 Odor Display--Booth Environment 19 Odor Display in CAVE 20 Odor Survey and Odor...HMDs, it may be welcome in some scenarios such as those that might be used for training medics. Odorant Survey and Odor Development A second area of

Blocking adenylyl cyclase inhibits olfactory generator currents induced by "IP(3)-odors".

PubMed

Chen, S; Lane, A P; Bock, R; Leinders-Zufall, T; Zufall, F

2000-07-01

Vertebrate olfactory receptor neurons (ORNs) transduce odor stimuli into electrical signals by means of an adenylyl cyclase/cAMP second messenger cascade, but it remains widely debated whether this cAMP cascade mediates transduction for all odorants or only certain odor classes. To address this problem, we have analyzed the generator currents induced by odors that failed to produce cAMP in previous biochemical assays but instead produced IP(3) ("IP(3)-odors"). We show that in single salamander ORNs, sensory responses to "cAMP-odors" and IP(3)-odors are not mutually exclusive but coexist in the same cells. The currents induced by IP(3)-odors exhibit identical biophysical properties as those induced by cAMP odors or direct activation of the cAMP cascade. By disrupting adenylyl cyclase to block cAMP formation using two potent antagonists of adenylyl cyclase, SQ22536 and MDL12330A, we show that this molecular step is necessary for the transduction of both odor classes. To assess whether these results are also applicable to mammals, we examine the electrophysiological responses to IP(3)-odors in intact mouse main olfactory epithelium (MOE) by recording field potentials. The results show that inhibition of adenylyl cyclase prevents EOG responses to both odor classes in mouse MOE, even when "hot spots" with heightened sensitivity to IP(3)-odors are examined.

Slow-Wave Sleep-Imposed Replay Modulates Both Strength and Precision of Memory

PubMed Central

2014-01-01

Odor perception is hypothesized to be an experience-dependent process involving the encoding of odor objects by distributed olfactory cortical ensembles. Olfactory cortical neurons coactivated by a specific pattern of odorant evoked input become linked through association fiber synaptic plasticity, creating a template of the familiar odor. In this way, experience and memory play an important role in odor perception and discrimination. In other systems, memory consolidation occurs partially via slow-wave sleep (SWS)-dependent replay of activity patterns originally evoked during waking. SWS is ideal for replay given hyporesponsive sensory systems, and thus reduced interference. Here, using artificial patterns of olfactory bulb stimulation in a fear conditioning procedure in the rat, we tested the effects of imposed post-training replay during SWS and waking on strength and precision of pattern memory. The results show that imposed replay during post-training SWS enhanced the subsequent strength of memory, whereas the identical replay during waking induced extinction. The magnitude of this enhancement was dependent on the timing of imposed replay relative to cortical sharp-waves. Imposed SWS replay of stimuli, which differed from the conditioned stimulus, did not affect conditioned stimulus memory strength but induced generalization of the fear memory to novel artificial patterns. Finally, post-training disruption of piriform cortex intracortical association fiber synapses, hypothesized to be critical for experience-dependent odor coding, also impaired subsequent memory precision but not strength. These results suggest that SWS replay in the olfactory cortex enhances memory consolidation, and that memory precision is dependent on the fidelity of that replay. PMID:24719093

Odor and odorous chemical emissions from dairy and swine facilities: Part 5-Simultaneous chemical and sensory analysis with Gas Chromatography - Mass Spectrometry - Olfactometry

USDA-ARS?s Scientific Manuscript database

Simultaneous chemical and sensory analyses using gas chromatography-mass spectrometry-olfactometry (GC-MS-O) for air samples collected at barn exhaust fans were used for quantification and ranking of odor impact of target odorous gases. Fifteen target odorous VOCs (odorants) were selected. Air sampl...

Does human body odor represent a significant and rewarding social signal to individuals high in social openness?

PubMed

Lübke, Katrin T; Croy, Ilona; Hoenen, Matthias; Gerber, Johannes; Pause, Bettina M; Hummel, Thomas

2014-01-01

Across a wide variety of domains, experts differ from novices in their response to stimuli linked to their respective field of expertise. It is currently unknown whether similar patterns can be observed with regard to social expertise. The current study therefore focuses on social openness, a central social skill necessary to initiate social contact. Human body odors were used as social cues, as they inherently signal the presence of another human being. Using functional MRI, hemodynamic brain responses to body odors of women reporting a high (n = 14) or a low (n = 12) level of social openness were compared. Greater activation within the inferior frontal gyrus and the caudate nucleus was observed in high socially open individuals compared to individuals low in social openness. With the inferior frontal gyrus being a crucial part of the human mirror neuron system, and the caudate nucleus being implicated in social reward, it is discussed whether human body odor might constitute more of a significant and rewarding social signal to individuals high in social openness compared to individuals low in social openness process.

Characterization of gaseous odorous emissions from a rendering plant by GC/MS and treatment by biofiltration.

PubMed

Anet, Benoît; Lemasle, Marguerite; Couriol, Catherine; Lendormi, Thomas; Amrane, Abdeltif; Le Cloirec, Pierre; Cogny, Gilles; Fillières, Romain

2013-10-15

This research focuses on the identification and quantification of odorous components in rendering plant emissions by GC/MS and other analytical methods, as well as the description of phenomena occurring in biofilter in order to improve the removal efficiency of industrial biofilters. Among the 36 compounds quantified in the process air stream, methanethiol, isopentanal and hydrogen sulfide, presented the major odorous contributions according to their high concentrations, generally higher than 10 mg m(-3), and their low odorous detection thresholds. The elimination of such component mixtures by biofiltration (Peat packing material, EBRT: 113 s) was investigated and revealed that more than 83% of hydrogen sulfide and isopentanal were removed by biofilter. Nevertheless, the incomplete degradation of such easily degradable pollutants suggested inappropriate conditions as lack of nutrients and acidic pH. These inadequate conditions could explain the lack of performance, especially observed on methanethiol (53% of RE) and the production of oxygenated and sulfur by-products by the biofilter itself. Copyright © 2013. Published by Elsevier Ltd.

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

PubMed

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

2017-07-05

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

Perceptual and processing differences between physical and dichorhinic odor mixtures.

PubMed

Schütze, M; Negoias, S; Olsson, M J; Hummel, T

2014-01-31

Perceptual integration of sensory input from our two nostrils has received little attention in comparison to lateralized inputs for vision and hearing. Here, we investigated whether a binary odor mixture of eugenol and l-carvone (smells of cloves and caraway) would be perceived differently if presented as a mixture in one nostril (physical mixture), vs. the same two odorants in separate nostrils (dichorhinic mixture). In parallel, we investigated whether the different types of presentation resulted in differences in olfactory event-related potentials (OERP). Psychophysical ratings showed that the dichorhinic mixtures were perceived as more intense than the physical mixtures. A tendency for shift in perceived quality was also observed. In line with these perceptual changes, the OERP showed a shift in latencies and amplitudes for early (more "sensory") peaks P1 and N1 whereas no significant differences were observed for the later (more "cognitive") peak P2. The results altogether suggest that the peripheral level is a site of interaction between odorants. Both psychophysical ratings and, for the first time, electrophysiological measurements converge on this conclusion. Copyright © 2013 IBRO. Published by Elsevier Ltd. All rights reserved.

Olfactory and quantitative analysis of aroma compounds in elder flower (Sambucus nigra L.) drink processed from five cultivars.

PubMed

Jørgensen, U; Hansen, M; Christensen, L P; Jensen, K; Kaack, K

2000-06-01

Fresh elder flowers (Sambucus nigra L.) were extracted with an aqueous solution containing sucrose, peeled lemon slices, tartaric acid, and sodium benzoate to make elder flower syrup. Aroma compounds emitted from the elder flower syrup were collected by the dynamic headspace technique and analyzed by GC-FID and GC-MS. A total of 59 compounds were identified, 18 of which have not previously been detected in elder flower products. The concentrations of the identified volatiles were measured in five elder cultivars, Allesoe, Donau, Sambu, Sampo, and Samyl, and significant differences were detected among cultivars in the concentration levels of 48 compounds. The odor of the volatiles was evaluated by the GC-sniffing technique. cis-Rose oxide, nerol oxide, hotrienol, and nonanal contributed to the characteristic elder flower odor, whereas linalool, alpha-terpineol, 4-methyl-3-penten-2-one, and (Z)-beta-ocimene contributed with floral notes. Fruity odors were associated with pentanal, heptanal, and beta-damascenone. Fresh and grassy odors were primarily correlated with hexanal, hexanol, and (Z)-3-hexenol.

Field Air Sampling and Simultaneous Chemical and Sensory Analysis of Livestock Odorants with Sorbent Tube GC-MS/Olfactometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang Shicheng; Department of Environmental Science and Engineering, Fudan University, Shanghai 200433; Cai Lingshuang

2009-05-23

Characterization and quantification of livestock odorants is one of the most challenging analytical tasks because odor-causing gases are very reactive, polar and often present at very low concentrations in a complex matrix of less important or irrelevant gases. The objective of this research was to develop a novel analytical method for characterization of the livestock odorants including their odor character, odor intensity, and hedonic tone and to apply this method for quantitative analysis of the key odorants responsible for livestock odor. Sorbent tubes packed with Tenax TA were used for field sampling. The automated one-step thermal desorption module coupled withmore » multidimensional gas chromatography-mass spectrometry/olfactometry system was used for simultaneous chemical and odor analysis. Fifteen odorous VOCs and semi-VOCs identified from different livestock species operations were quantified. Method detection limits ranges from 40 pg for skatole to 3590 pg for acetic acid. In addition, odor character, odor intensity and hedonic tone associated with each of the target odorants are also analyzed simultaneously. We found that the mass of each VOCs in the sample correlates well with the log stimulus intensity. All of the correlation coefficients (R{sup 2}) are greater than 0.74, and the top 10 correlation coefficients were greater than 0.90.« less

Odor Sampling: Techniques and Strategies for the Estimation of Odor Emission Rates from Different Source Types

PubMed Central

Capelli, Laura; Sironi, Selena; Rosso, Renato Del

2013-01-01

Sampling is one of the main issues pertaining to odor characterization and measurement. The aim of sampling is to obtain representative information on the typical characteristics of an odor source by means of the collection of a suitable volume fraction of the effluent. The most important information about an emission source for odor impact assessment is the so-called Odor Emission Rate (OER), which represents the quantity of odor emitted per unit of time, and is expressed in odor units per second (ou·s−1). This paper reviews the different odor sampling strategies adopted depending on source type. The review includes an overview of odor sampling regulations and a detailed discussion of the equipment to be used as well as the mathematical considerations to be applied to obtain the OER in relation to the sampled source typology. PMID:23322098

Odor-evoked inhibition of olfactory sensory neurons drives olfactory perception in Drosophila.

PubMed

Cao, Li-Hui; Yang, Dong; Wu, Wei; Zeng, Xiankun; Jing, Bi-Yang; Li, Meng-Tong; Qin, Shanshan; Tang, Chao; Tu, Yuhai; Luo, Dong-Gen

2017-11-07

Inhibitory response occurs throughout the nervous system, including the peripheral olfactory system. While odor-evoked excitation in peripheral olfactory cells is known to encode odor information, the molecular mechanism and functional roles of odor-evoked inhibition remain largely unknown. Here, we examined Drosophila olfactory sensory neurons and found that inhibitory odors triggered outward receptor currents by reducing the constitutive activities of odorant receptors, inhibiting the basal spike firing in olfactory sensory neurons. Remarkably, this odor-evoked inhibition of olfactory sensory neurons elicited by itself a full range of olfactory behaviors from attraction to avoidance, as did odor-evoked olfactory sensory neuron excitation. These results indicated that peripheral inhibition is comparable to excitation in encoding sensory signals rather than merely regulating excitation. Furthermore, we demonstrated that a bidirectional code with both odor-evoked inhibition and excitation in single olfactory sensory neurons increases the odor-coding capacity, providing a means of efficient sensory encoding.

Odor sampling: techniques and strategies for the estimation of odor emission rates from different source types.

PubMed

Capelli, Laura; Sironi, Selena; Del Rosso, Renato

2013-01-15

Sampling is one of the main issues pertaining to odor characterization and measurement. The aim of sampling is to obtain representative information on the typical characteristics of an odor source by means of the collection of a suitable volume fraction of the effluent. The most important information about an emission source for odor impact assessment is the so-called Odor Emission Rate (OER), which represents the quantity of odor emitted per unit of time, and is expressed in odor units per second (ou∙s-1). This paper reviews the different odor sampling strategies adopted depending on source type. The review includes an overview of odor sampling regulations and a detailed discussion of the equipment to be used as well as the mathematical considerations to be applied to obtain the OER in relation to the sampled source typology.

Gamma and Beta Oscillations Define a Sequence of Neurocognitive Modes Present in Odor Processing

PubMed Central

Frederick, Donald E.; Brown, Austin; Brim, Elizabeth; Mehta, Nisarg; Vujovic, Mark

2016-01-01

Olfactory system beta (15–35 Hz) and gamma (40–110 Hz) oscillations of the local field potential in mammals have both been linked to odor learning and discrimination. Gamma oscillations represent the activity of a local network within the olfactory bulb, and beta oscillations represent engagement of a systemwide network. Here, we test whether beta and gamma oscillations represent different cognitive modes using the different demands of go/no-go and two-alternative choice tasks that previously were suggested to favor beta or gamma oscillations, respectively. We reconcile previous studies and show that both beta and gamma oscillations occur in both tasks, with gamma dominating the early odor sampling period (2–4 sniffs) and beta dominating later. The relative power and coherence of both oscillations depend separately on multiple factors within both tasks without categorical differences across tasks. While the early/gamma-associated period occurs in all trials, rats can perform above chance without the later/beta-associated period. Longer sampling, which includes beta oscillations, is associated with better performance. Gamma followed by beta oscillations therefore represents a sequence of cognitive and neural states during odor discrimination, which can be separately modified depending on the demands of a task and odor discrimination. Additionally, fast (85 Hz) and slow (70 Hz) olfactory bulb gamma oscillation sub-bands have been hypothesized to represent tufted and mitral cell networks, respectively (Manabe and Mori, 2013). We find that fast gamma favors the early and slow gamma the later (beta-dominated) odor-sampling period and that the relative contributions of these oscillations are consistent across tasks. SIGNIFICANCE STATEMENT Olfactory system gamma (40–110 Hz) and beta (15–35 Hz) oscillations of the local field potential indicate different neural firing statistics and functional circuits. We show that gamma and beta oscillations occur in stereotyped sequence during odor sampling in associative tasks, with local gamma dominating the first 250 ms of odor sniffing, followed by systemwide beta as behavioral responses are prepared. Oscillations and coupling strength between brain regions are modulated by task, odor, and learning, showing that task features can dramatically adjust the dynamics of a cortical sensory system, which changes state every ∼250 ms. Understanding cortical circuits, even at the biophysical level, depends on careful use of multiple behavioral contexts and stimuli. PMID:27445151

Gamma and Beta Oscillations Define a Sequence of Neurocognitive Modes Present in Odor Processing.

PubMed

Frederick, Donald E; Brown, Austin; Brim, Elizabeth; Mehta, Nisarg; Vujovic, Mark; Kay, Leslie M

2016-07-20

Olfactory system beta (15-35 Hz) and gamma (40-110 Hz) oscillations of the local field potential in mammals have both been linked to odor learning and discrimination. Gamma oscillations represent the activity of a local network within the olfactory bulb, and beta oscillations represent engagement of a systemwide network. Here, we test whether beta and gamma oscillations represent different cognitive modes using the different demands of go/no-go and two-alternative choice tasks that previously were suggested to favor beta or gamma oscillations, respectively. We reconcile previous studies and show that both beta and gamma oscillations occur in both tasks, with gamma dominating the early odor sampling period (2-4 sniffs) and beta dominating later. The relative power and coherence of both oscillations depend separately on multiple factors within both tasks without categorical differences across tasks. While the early/gamma-associated period occurs in all trials, rats can perform above chance without the later/beta-associated period. Longer sampling, which includes beta oscillations, is associated with better performance. Gamma followed by beta oscillations therefore represents a sequence of cognitive and neural states during odor discrimination, which can be separately modified depending on the demands of a task and odor discrimination. Additionally, fast (85 Hz) and slow (70 Hz) olfactory bulb gamma oscillation sub-bands have been hypothesized to represent tufted and mitral cell networks, respectively (Manabe and Mori, 2013). We find that fast gamma favors the early and slow gamma the later (beta-dominated) odor-sampling period and that the relative contributions of these oscillations are consistent across tasks. Olfactory system gamma (40-110 Hz) and beta (15-35 Hz) oscillations of the local field potential indicate different neural firing statistics and functional circuits. We show that gamma and beta oscillations occur in stereotyped sequence during odor sampling in associative tasks, with local gamma dominating the first 250 ms of odor sniffing, followed by systemwide beta as behavioral responses are prepared. Oscillations and coupling strength between brain regions are modulated by task, odor, and learning, showing that task features can dramatically adjust the dynamics of a cortical sensory system, which changes state every ∼250 ms. Understanding cortical circuits, even at the biophysical level, depends on careful use of multiple behavioral contexts and stimuli. Copyright © 2016 the authors 0270-6474/16/367750-18$15.00/0.

Assessment of the roles of reactive oxygen species in the UV and visible light photocatalytic degradation of cyanotoxins and water taste and odor compounds using C-TiO2.

PubMed

Fotiou, Theodora; Triantis, Theodoros M; Kaloudis, Triantafyllos; O'Shea, Kevin E; Dionysiou, Dionysios D; Hiskia, Anastasia

2016-03-01

Visible light (VIS) photocatalysis has large potential as a sustainable water treatment process, however the reaction pathways and degradation processes of organic pollutants are not yet clearly defined. The presence of cyanobacteria cause water quality problems since several genera can produce potent cyanotoxins, harmful to human health. In addition, cyanobacteria produce taste and odor compounds, which pose serious aesthetic problems in drinking water. Although photocatalytic degradation of cyanotoxins and taste and odor compounds have been reported under UV-A light in the presence of TiO2, limited studies have been reported on their degradation pathways by VIS photocatalysis of these problematic compounds. The main objectives of this work were to study the VIS photocatalytic degradation process, define the reactive oxygen species (ROS) involved and elucidate the reaction mechanisms. We report carbon doped TiO2 (C-TiO2) under VIS leads to the slow degradation of cyanotoxins, microcystin-LR (MC-LR) and cylindrospermopsin (CYN), while taste and odor compounds, geosmin and 2-methylisoborneol, were not appreciably degraded. Further studies were carried-out employing several specific radical scavengers (potassium bromide, isopropyl alcohol, sodium azide, superoxide dismutase and catalase) and probes (coumarin) to assess the role of different ROS (hydroxyl radical OH, singlet oxygen (1)O2, superoxide radical anion [Formula: see text] ) in the degradation processes. Reaction pathways of MC-LR and CYN were defined through identification and monitoring of intermediates using liquid chromatography tandem mass spectrometry (LC-MS/MS) for VIS in comparison with UV-A photocatalytic treatment. The effects of scavengers and probes on the degradation process under VIS, as well as the differences in product distributions under VIS and UV-A, suggested that the main species in VIS photocatalysis is [Formula: see text] , with OH and (1)O2 playing minor roles in the degradation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Application of Odor Sensors to Ore Sorting and Mill Feed Control

DOE Office of Scientific and Technical Information (OSTI.GOV)

Michael G. Nelson

2005-08-01

Control of the feed provided to mineral processing facilities is a continuing challenge. Much effort is currently being devoted to overcoming these problems. These projects are usually described under the general headings of Mine-to-Mill Integration or Mine-Mill Optimization. It should be possible to combine the knowledge of ore type, mineralogy, and other characteristics (located in the mine modeling system), with the advanced capabilities of state-of-the-art mill control systems, to achieve an improved level of control in mineral processing that will allow optimization of the mill processes on an almost real-time basis. This is not happening because mill feed it ismore » often treated as a uniform material, when in reality it varies in composition and characteristics. An investigation was conducted to assess the suitability of odor sensors for maintaining traceability in ore production and processing. Commercially available sensors are now used in food processing, environmental monitoring, and other applications and can detect the presence of very small amounts (0.1-500 ppm) of some molecules. An assortment of such molecules could be used to ''tag'' blocks of ore as they are mined, according to their respective characteristics. Then, as the ore came into the mill, an array of ''electronic noses'' could be used to assess its characteristics in real time. It was found that the Cyranose 320{trademark}, a commercially available odor sensor, can easily distinguish among samples of rock marked with almond, cinnamon, citronella, lemon, and orange oils. Further, the sensor could detect mixtures of rocks marked with various combinations of these oils. Treatment of mixtures of galena and silica with odorant compounds showed no detrimental effects on flotation response in laboratory tests. Additional work is recommended to determine how this concept can be extended to the marking of large volumes of materials.« less

Order of exposure to pleasant and unpleasant odors affects autonomic nervous system response.

PubMed

Horii, Yuko; Nagai, Katsuya; Nakashima, Toshihiro

2013-04-15

When mammals are exposed to an odor, that odor is expected to elicit a physiological response in the autonomic nervous system. An unpleasant aversive odor causes non-invasive stress, while a pleasant odor promotes healing and relaxation in mammals. We hypothesized that pleasant odors might reduce a stress response previously induced by an aversive predator odor. Rats were thus exposed to pleasant and unpleasant odors in different orders to determine whether the order of odor exposure had an effect on the physiological response in the autonomic nervous system. The first trial examined autonomic nerve activity via sympathetic and parasympathetic nerve response while the second trial examined body temperature response. Initial exposure to a pleasant odor elicited a positive response and secondary exposure to an unpleasant odor elicited a negative response, as expected. However, we found that while initial exposure to an unpleasant odor elicited a negative stress response, subsequent secondary exposure to a pleasant odor not only did not alleviate that negative response, but actually amplified it. These findings were consistent for both the autonomic nerve activity response trial and the body temperature response trial. The trial results suggest that exposure to specific odors does not necessarily result in the expected physiological response and that the specific order of exposure plays an important role. Our study should provide new insights into our understanding of the physiological response in the autonomic nervous system related to odor memory and discrimination and point to areas that require further research. Copyright © 2013 Elsevier B.V. All rights reserved.

OdorMapComparer: an application for quantitative analyses and comparisons of fMRI brain odor maps.

PubMed

Liu, Nian; Xu, Fuqiang; Miller, Perry L; Shepherd, Gordon M

2007-01-01

Brain odor maps are reconstructed flat images that describe the spatial activity patterns in the glomerular layer of the olfactory bulbs in animals exposed to different odor stimuli. We have developed a software application, OdorMapComparer, to carry out quantitative analyses and comparisons of the fMRI odor maps. This application is an open-source window program that first loads two odor map images being compared. It allows image transformations including scaling, flipping, rotating, and warping so that the two images can be appropriately aligned to each other. It performs simple subtraction, addition, and average of signals in the two images. It also provides comparative statistics including the normalized correlation (NC) and spatial correlation coefficient. Experimental studies showed that the rodent fMRI odor maps for aliphatic aldehydes displayed spatial activity patterns that are similar in gross outlines but somewhat different in specific subregions. Analyses with OdorMapComparer indicate that the similarity between odor maps decreases with increasing difference in the length of carbon chains. For example, the map of butanal is more closely related to that of pentanal (with a NC = 0.617) than to that of octanal (NC = 0.082), which is consistent with animal behavioral studies. The study also indicates that fMRI odor maps are statistically odor-specific and repeatable across both the intra- and intersubject trials. OdorMapComparer thus provides a tool for quantitative, statistical analyses and comparisons of fMRI odor maps in a fashion that is integrated with the overall odor mapping techniques.

Evaluation of the Effectiveness of Five Odor Reducing Agents for Sewer System Odors Using an On-Line Total Reduced Sulfur Analyzer

PubMed Central

Choi, Il; Lee, Hyunjoo; Shin, Joungdu; Kim, Hyunook

2012-01-01

Sewer odors have been a concern to citizens of the Metropolitan Seoul region, which has installed combined sewer systems (CSSs) in 86% of its area. Although a variety of odorants are released from sewers, volatile sulfur compounds (VSCs) have been recognized as major ones. A number of technologies have been proposed to monitor or control odors from sewers. One of the most popular strategies adopted for the control of sewage odor is by applying a commercial odor-reducing agent into the sewer. In this study, the effectiveness of five different commercial odor-reducing agents (i.e., an odor masking agent, an alkaline solution, two microbial agents, and a chemical oxidant) was evaluated by continuously monitoring VSCs released from the sewer with an on-line total reduced sulfur (TRS) analyzer before and after each agent was sprayed into CSSs at five different locations of the city. In short, when the effectiveness of odor treatment was tested in the sewer system using five commercial odor reducing treatments, only the chemical oxidant was good enough to reduce the odor in terms of TRS levels measured before and after the application (p < 0.01). PMID:23223148

An odor interaction model of binary odorant mixtures by a partial differential equation method.

PubMed

Yan, Luchun; Liu, Jiemin; Wang, Guihua; Wu, Chuandong

2014-07-09

A novel odor interaction model was proposed for binary mixtures of benzene and substituted benzenes by a partial differential equation (PDE) method. Based on the measurement method (tangent-intercept method) of partial molar volume, original parameters of corresponding formulas were reasonably displaced by perceptual measures. By these substitutions, it was possible to relate a mixture's odor intensity to the individual odorant's relative odor activity value (OAV). Several binary mixtures of benzene and substituted benzenes were respectively tested to establish the PDE models. The obtained results showed that the PDE model provided an easily interpretable method relating individual components to their joint odor intensity. Besides, both predictive performance and feasibility of the PDE model were proved well through a series of odor intensity matching tests. If combining the PDE model with portable gas detectors or on-line monitoring systems, olfactory evaluation of odor intensity will be achieved by instruments instead of odor assessors. Many disadvantages (e.g., expense on a fixed number of odor assessors) also will be successfully avoided. Thus, the PDE model is predicted to be helpful to the monitoring and management of odor pollutions.

The effects of predator odors in mammalian prey species: a review of field and laboratory studies.

PubMed

Apfelbach, Raimund; Blanchard, Caroline D; Blanchard, Robert J; Hayes, R Andrew; McGregor, Iain S

2005-01-01

Prey species show specific adaptations that allow recognition, avoidance and defense against predators. For many mammalian species this includes sensitivity towards predator-derived odors. The typical sources of such odors include predator skin and fur, urine, feces and anal gland secretions. Avoidance of predator odors has been observed in many mammalian prey species including rats, mice, voles, deer, rabbits, gophers, hedgehogs, possums and sheep. Field and laboratory studies show that predator odors have distinctive behavioral effects which include (1) inhibition of activity, (2) suppression of non-defensive behaviors such as foraging, feeding and grooming, and (3) shifts to habitats or secure locations where such odors are not present. The repellent effect of predator odors in the field may sometimes be of practical use in the protection of crops and natural resources, although not all attempts at this have been successful. The failure of some studies to obtain repellent effects with predator odors may relate to (1) mismatches between the predator odors and prey species employed, (2) strain and individual differences in sensitivity to predator odors, and (3) the use of predator odors that have low efficacy. In this regard, a small number of recent studies have suggested that skin and fur-derived predator odors may have a more profound lasting effect on prey species than those derived from urine or feces. Predator odors can have powerful effects on the endocrine system including a suppression of testosterone and increased levels of stress hormones such as corticosterone and ACTH. Inhibitory effects of predator odors on reproductive behavior have been demonstrated, and these are particularly prevalent in female rodent species. Pregnant female rodents exposed to predator odors may give birth to smaller litters while exposure to predator odors during early life can hinder normal development. Recent research is starting to uncover the neural circuitry activated by predator odors, leading to hypotheses about how such activation leads to observable effects on reproduction, foraging and feeding.

[Evaluation of treatment technology of odor pollution source in petrochemical industry].

PubMed

Mu, Gui-Qin; Sui, Li-Hua; Guo, Ya-Feng; Ma, Chuan-Jun; Yang, Wen-Yu; Gao, Yang

2013-12-01

Using an environmental technology assessment system, we put forward the evaluation index system for treatment technology of the typical odor pollution sources in the petroleum refining process, which has been applied in the assessment of the industrial technology. And then the best available techniques are selected for emissions of gas refinery sewage treatment plant, headspace gas of acidic water jars, headspace gas of cold coke jugs/intermediate oil tank/dirty oil tank, exhaust of oxidative sweetening, and vapors of loading and unloading oil.

Changes in olfactory bulb volume following lateralized olfactory training.

PubMed

Negoias, S; Pietsch, K; Hummel, T

2017-08-01

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

Molecular Characterization and Differential Expression of Olfactory Genes in the Antennae of the Black Cutworm Moth Agrotis ipsilon

PubMed Central

Gu, Shao-Hua; Sun, Liang; Yang, Ruo-Nan; Wu, Kong-Ming; Guo, Yu-Yuan; Li, Xian-Chun; Zhou, Jing-Jiang; Zhang, Yong-Jun

2014-01-01

Insects use their sensitive and selective olfactory system to detect outside chemical odorants, such as female sex pheromones and host plant volatiles. Several groups of olfactory proteins participate in the odorant detection process, including odorant binding proteins (OBPs), chemosensory proteins (CSPs), odorant receptors (ORs), ionotropic receptors (IRs) and sensory neuron membrane proteins (SNMPs). The identification and functional characterization of these olfactory proteins will enhance our knowledge of the molecular basis of insect chemoreception. In this study, we report the identification and differential expression profiles of these olfactory genes in the black cutworm moth Agrotis ipsilon. In total, 33 OBPs, 12 CSPs, 42 ORs, 24 IRs, 2 SNMPs and 1 gustatory receptor (GR) were annotated from the A. ipsilon antennal transcriptomes, and further RT-PCR and RT-qPCR revealed that 22 OBPs, 3 CSPs, 35 ORs, 14 IRs and the 2 SNMPs are uniquely or primarily expressed in the male and female antennae. Furthermore, one OBP (AipsOBP6) and one CSP (AipsCSP2) were exclusively expressed in the female sex pheromone gland. These antennae-enriched OBPs, CSPs, ORs, IRs and SNMPs were suggested to be responsible for pheromone and general odorant detection and thus could be meaningful target genes for us to study their biological functions in vivo and in vitro. PMID:25083706

Prenatal and Early Postnatal Odorant Exposure Heightens Odor-Evoked Mitral Cell Responses in the Mouse Olfactory Bulb

PubMed Central

2017-01-01

Abstract Early sensory experience shapes the anatomy and function of sensory circuits. In the mouse olfactory bulb (OB), prenatal and early postnatal odorant exposure through odorized food (food/odorant pairing) not only increases the volume of activated glomeruli but also increases the number of mitral and tufted cells (M/TCs) connected to activated glomeruli. Given the importance of M/TCs in OB output and in mediating lateral inhibitory networks, increasing the number of M/TCs connected to a single glomerulus may significantly change odorant representation by increasing the total output of that glomerulus and/or by increasing the strength of lateral inhibition mediated by cells connected to the affected glomerulus. Here, we seek to understand the functional impact of this long-term odorant exposure paradigm on the population activity of mitral cells (MCs). We use viral expression of GCaMP6s to examine odor-evoked responses of MCs following prenatal and early postnatal odorant exposure to two dissimilar odorants, methyl salicylate (MS) and hexanal, which are both strong activators of glomeruli on the dorsal OB surface. Previous work suggests that odor familiarity may decrease odor-evoked MC response in rodents. However, we find that early food-based odorant exposure significantly changes MC responses in an unexpected way, resulting in broad increases in the amplitude, number, and reliability of excitatory MC responses across the dorsal OB. PMID:28955723

The Effects of Emotional Visual Context on the Encoding and Retrieval of Body Odor Information.

PubMed

Parma, Valentina; Macedo, Stephanie; Rocha, Marta; Alho, Laura; Ferreira, Jacqueline; Soares, Sandra C

2018-04-01

Conditions during information encoding and retrieval are known to influence the sensory material stored and its recapitulation. However, little is known about such processes in olfaction. Here, we capitalized on the uniqueness of body odors (BOs) which, similar to fingerprints, allow for the identification of a specific person, by associating their presentation to a negative or a neutral emotional context. One hundred twenty-five receivers (68 F) were exposed to a male BO while watching either criminal or neutral videos (encoding phase) and were subsequently asked to recognize the target BO within either a congruent or an incongruent visual context (retrieval phase). The results showed that criminal videos were rated as more vivid, unpleasant, and arousing than neutral videos both at encoding and retrieval. Moreover, in terms of BO ratings, we found that odor intensity and arousal allow to distinguish the target from the foils when congruent criminal information is presented at encoding and retrieval. Finally, the accuracy performance was not significantly different from chance level for either condition. These findings provide insights on how olfactory memories are processed in emotional situations.

Chemosensitivity of the osphradium of the pond snail Lymnaea stagnalis

PubMed

Wedemeyer; Schild

1995-01-01

The osphradium of the pond snail Lymnaea stagnalis was studied to determine the stimuli to which this organ responds. The following stimuli were tested: hypoxia, hypercapnia, a mixture of amino acids, a mixture of citralva and amyl acetate and a mixture of lyral, lilial and ethylvanillin. The mean nerve activity consistently increased with elevated PCO2, whereas hypoxia produced variable effects. The nerve activity became rhythmic upon application of citralva and amyl acetate, but it increased in a non-rhythmic way upon application of the other two odorant mixtures tested. Whole-cell patch-clamp recordings were made from a group of 15 neurones that lay next to the issuing osphradial nerve, to determine whether ganglion cells were involved in olfactory signal processing. All neurones tested responded to at least one of the three mixtures of odorants. Both excitatory and inhibitory responses occurred. Our results indicate that the osphradium of the pond snail Lymnaea stagnalis is sensitive to elevated PCO2 as well as to three different classes of odorants. In addition, at least some neurones within the osphradium are involved in the processing of olfactory information.

Systematic tracking, visualizing, and interpreting of consumer feedback for drinking water quality.

PubMed

Dietrich, Andrea M; Phetxumphou, Katherine; Gallagher, Daniel L

2014-12-01

Consumer feedback and complaints provide utilities with useful data about consumer perceptions of aesthetic water quality in the distribution system. This research provides a systematic approach to interpret consumer complaint water quality data provided by four water utilities that recorded consumer complaints, but did not routinely process the data. The utilities tended to write down a myriad of descriptors that were too numerous or contained a variety of spellings so that electronic "harvesting" was not possible and much manual labor was required to categorize the complaints into majors areas, such as suggested by the Drinking Water Taste and Odor Wheel or existing check-sheets. When the consumer complaint data were categorized and visualized using spider (or radar) and run-time plots, major taste, odor, and appearance patterns emerged that clarified the issue and could provide guidance to the utility on the nature and extent of the problem. A caveat is that while humans readily identify visual issues with the water, such as color, cloudiness, or rust, describing specific tastes and odors in drinking water is acknowledged to be much more difficult for humans to achieve without training. This was demonstrated with two utility groups and a group of consumers identifying the odors of orange, 2-methylisoborneol, and dimethyl trisulfide. All three groups readily and succinctly identified the familiar orange odor. The two utility groups were much more able to identify the musty odor of 2-methylisoborneol, which was likely familiar to them from their work with raw and finished water. Dimethyl trisulfide, a garlic-onion odor associated with sulfur compounds in drinking water, was the least familiar to all three groups, although the laboratory staff did best. These results indicate that utility personnel should be tolerant of consumers who can assuredly say the water is different, but cannot describe the problem. Also, it indicates that a T&O program at a utility would benefit from identification of aesthetic issues in water. Copyright © 2014 Elsevier Ltd. All rights reserved.

Natural gas odor level testing: Instruments and applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roberson, E.H.

1995-12-01

An odor in natural and LP gases is necessary. The statistics are overwhelming; when gas customers can smell a leak before the percentage of gas in air reaches a combustible mixture, the chances of an accident are greatly reduced. How do gas companies determine if there is sufficient odor reaching every gas customers home? Injection equipment is important. The rate and quality of odorant is important. Nevertheless, precision odorization alone does not guarantee that customers` homes always have gas with a readily detectable odor. To secure that goal, odor monitoring instruments are necessary.

Descriptive epidemiology of indoor odor complaints at a large teaching institution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boswell, R.T.; DiBerardinis, L.; Ducatman, A.

1994-04-01

Investigation of indoor odor complaints consumes a substantial portion of the time and resources of many industrial hygiene offices, yet very little information has been published on the subject. We examined 3 years of data on indoor odor complaints at the Massachusetts Institute of Technology in Cambridge, Massachusetts in order to identify factors that may trigger complaints of odors. Plumbing and maintenance accounted for the majority of activities responsible for the identified sources (35% of calls), while research and teaching activities accounted for only 11 percent of calls. A larger number of calls were received during the winter months whenmore » windows are closed and school is in session. There was generally good correlation between the description of an odor by a complainant and the actual source. Offices/secretarial areas/office support rooms accounted for almost half of the calls, while laboratory facilities accounted for 19 percent of the calls. Despite the fact that the chemistry department was responsible for the most number of calls, the odor sources from these complaints were related primarily to plumbing (dried sink and floor drains) and not the chemicals used for research and teaching. Four types of abatement measures were used when odor sources could be identified: natural dissipation of the odor (23%), advice for prevention of future odors (11%), controlling an odor source (16%), and correction of the odor source (33%). We conclude that the majority of sources of indoor odors which trigger complaints are related to the maintenance of the physical plant, and that complaints are likely to be generated by unfamiliarity with certain odors. Recommendations are given to help reduce indoor odors and the time-consuming investigations into complaints from these odors. 10 refs., 4 figs.« less

Effect of fragrance use on discrimination of individual body odor.

PubMed

Allen, Caroline; Havlíček, Jan; Roberts, S Craig

2015-01-01

Previous research suggests that artificial fragrances may be chosen to complement or enhance an individual's body odor, rather than simply masking it, and that this may create an odor blend with an emergent quality that is perceptually distinguishable from body odor or fragrance alone. From this, it can be predicted that a new emergent odor might be more easily identified than an individual's body odor in isolation. We used a triangle test paradigm to assess whether fragrance affects people's ability to distinguish between individual odors. Six male and six female donors provided axillary odor samples in three conditions (without fragrance, wearing their own fragrance, and wearing an assigned fragrance). In total, 296 female and 131 male participants selected the odd one from three odor samples (two from one donor, one from another; both of the same sex). We found that participants could discriminate between the odors at above chance levels in all three odor conditions. Olfactory identification ability (measured using Sniffin' Sticks) positively predicted discrimination performance, and sex differences in performance were also observed, with female raters being correct more often than men. Success rates were also higher for odors of male donors. Additionally, while performance was above chance in all conditions, individual odor discrimination varied across the three conditions. Discrimination rate was significantly higher in the "no fragrance" condition than either of the fragranced conditions. Importantly, however, discrimination rate was also significantly higher in the "own fragrance" condition than the "assigned fragrance" condition, suggesting that naturally occurring variance in body odor is more preserved when blended with fragrances that people choose for themselves, compared with other fragrances. Our data are consistent with the idea that fragrance choices are influenced by fragrance interactions with an individual's own body odor.

Effect of fragrance use on discrimination of individual body odor

PubMed Central

Allen, Caroline; Havlíček, Jan; Roberts, S. Craig

2015-01-01

Previous research suggests that artificial fragrances may be chosen to complement or enhance an individual’s body odor, rather than simply masking it, and that this may create an odor blend with an emergent quality that is perceptually distinguishable from body odor or fragrance alone. From this, it can be predicted that a new emergent odor might be more easily identified than an individual’s body odor in isolation. We used a triangle test paradigm to assess whether fragrance affects people’s ability to distinguish between individual odors. Six male and six female donors provided axillary odor samples in three conditions (without fragrance, wearing their own fragrance, and wearing an assigned fragrance). In total, 296 female and 131 male participants selected the odd one from three odor samples (two from one donor, one from another; both of the same sex). We found that participants could discriminate between the odors at above chance levels in all three odor conditions. Olfactory identification ability (measured using Sniffin’ Sticks) positively predicted discrimination performance, and sex differences in performance were also observed, with female raters being correct more often than men. Success rates were also higher for odors of male donors. Additionally, while performance was above chance in all conditions, individual odor discrimination varied across the three conditions. Discrimination rate was significantly higher in the “no fragrance” condition than either of the fragranced conditions. Importantly, however, discrimination rate was also significantly higher in the “own fragrance” condition than the “assigned fragrance” condition, suggesting that naturally occurring variance in body odor is more preserved when blended with fragrances that people choose for themselves, compared with other fragrances. Our data are consistent with the idea that fragrance choices are influenced by fragrance interactions with an individual’s own body odor. PMID:26300812

Restrained eaters show altered brain response to food odor.

PubMed

Kemmotsu, Nobuko; Murphy, Claire

2006-02-28

Do restrained and unrestrained eaters differ in their brain response to food odor? We addressed this question by examining restrained eaters' brain response to food (chocolate) and non-food (geraniol, floral) odors, both when odor was attended to and when ignored. Using olfactory event-related potentials (OERPs), we found that restrained eaters and controls responded similarly to the non-food odor; however, unlike controls, restrained eaters showed no increase in brain response to the food odor when they focused attention on it. Rather, restrained eaters showed attenuated OERP amplitudes to the food odor in both attended and ignored conditions, suggesting that the brain's response to attended food odor was abnormally suppressed.

Cognitive Facilitation Following Intentional Odor Exposure

PubMed Central

Johnson, Andrew J.

2011-01-01

This paper reviews evidence that, in addition to incidental olfactory pollutants, intentional odor delivery can impact cognitive operations both positively and negatively. Evidence for cognitive facilitation/interference is reviewed alongside four potential explanations for odor-induced effects. It is concluded that the pharmacological properties of odors can induce changes in cognition. However, these effects can be accentuated/attenuated by the shift in mood following odor exposure, expectancy of cognitive effects, and cues to behavior via the contextual association with the odor. It is proposed that greater consideration is required in the intentional utilization of odors within both industrial and private locations, since differential effects are observed for odors with positive hedonic qualities. PMID:22163909

Olfactory receptor antagonism between odorants

PubMed Central

Oka, Yuki; Omura, Masayo; Kataoka, Hiroshi; Touhara, Kazushige

2004-01-01

The detection of thousands of volatile odorants is mediated by several hundreds of different G protein-coupled olfactory receptors (ORs). The main strategy in encoding odorant identities is a combinatorial receptor code scheme in that different odorants are recognized by different sets of ORs. Despite increasing information on agonist–OR combinations, little is known about the antagonism of ORs in the mammalian olfactory system. Here we show that odorants inhibit odorant responses of OR(s), evidence of antagonism between odorants at the receptor level. The antagonism was demonstrated in a heterologous OR-expression system and in single olfactory neurons that expressed a given OR, and was also visualized at the level of the olfactory epithelium. Dual functions of odorants as an agonist and an antagonist to ORs indicate a new aspect in the receptor code determination for odorant mixtures that often give rise to novel perceptual qualities that are not present in each component. The current study also provides insight into strategies to modulate perceived odorant quality. PMID:14685265

Ventilation/odor study, field study. Final report, Volume I

DOE Office of Scientific and Technical Information (OSTI.GOV)

Duffee, R.A.; Jann, P.

1981-04-01

The results are presented of field investigations in schools, hospitals, and an office building on the relation between ventilation rate and odor within the buildings. The primary objective of the study was to determine: the reduction in ventilation rates that could be achieved in public buildings without causing adverse effects on odor; the sources of odor in public buildings; and the identity of the odorants. The variables of particular interest include: type of odor, occupant density, odorant identity and concentration, differences in impressions between occupants adapted to prevailing conditions and visitors, and the influence of temperature and humidity on bothmore » the generation and perception of common contaminants. Sensory odor measurements, chemical measurements, fresh air ventilation measurements, and acceptability evaluations via questionnaires were made. Sensory odor levels were found to be quite low in most buildings tested. A three-to-five-fold reduction in the fresh air ventilation in schools, hospitals, and office buildings can be achieved without significantly affecting perceived odor intensities or detectability. Tobacco smoking was found to be the most significant, pervasive contributor to interior odor level. Total hydrocarbon content of indoor air varies directly with ventilation rates; odor, however, does not. The complete set of reduced data are contained in Volume II. (LEW)« less

Elaborated Odor Test for Extended Exposure

NASA Technical Reports Server (NTRS)

Buchanan, Vanessa D.; Henry, Emily J.; Mast, Dion J.; Harper, Susana A.; Beeson, Harold D.; Tapia, Alma S.

2016-01-01

Concerns were raised when incidental exposure to a proprietary bonding material revealed the material had an irritating odor. The NASA-STD-6001B document describes a supplemental test method option for programs to evaluate materials with odor concerns (Test 6, Odor Assessment). In addition to the supplemental standard odor assessment with less than 10 seconds of exposure, the NASA White Sands Test Facility (WSTF) Materials Flight Acceptance Testing section was requested to perform an odor test with an extended duration to evaluate effects of an extended exposure and to more closely simulate realistic exposure scenarios. With approval from the NASA Johnson Space Center Industrial Hygienist, WSTF developed a 15-minute odor test method. WSTF performed this extended-duration odor test to evaluate the odor and physical effects of the bonding material configured between two aluminum plates, after the safety of the gas was verified via toxicity analysis per NASA-STD-6001B Test 7, Determination of Offgassed Products. During extended-duration testing, odor panel members were arranged near the test material in a small room with the air handlers and doors closed to minimize dilution. The odor panel members wafted gas toward themselves and recorded their individual assessments of odor and physical effects at various intervals during the 15-minute exposure and posttest. A posttest interview was conducted to obtain further information. Testing was effective in providing data for comparison and selection of an optimal offgassing and odor containment configuration. The developed test method for extended exposure is proposed as a useful tool for further evaluating materials with identified odors of concern if continued use of the material is anticipated.

Body Odor Based Personality Judgments: The Effect of Fragranced Cosmetics

PubMed Central

Sorokowska, Agnieszka; Sorokowski, Piotr; Havlíček, Jan

2016-01-01

People can accurately assess various personality traits of others based on body odor (BO) alone. Previous studies have shown that correlations between odor ratings and self-assessed personality dimensions are evident for assessments of neuroticism and dominance. Here, we tested differences between assessments based on natural body odor alone, without the use of cosmetics and assessments based on the body odor of people who were allowed to use cosmetics following their daily routine. Sixty-seven observers assessed samples of odors from 113 odor donors (each odor donor provided two samples – one with and one without cosmetic use); the donors provided their personality ratings, and the raters judged personality characteristics of the donors based on the provided odor samples. Correlations between observers’ ratings and self-rated neuroticism were stronger when raters assessed body odor in the natural body odor condition (natural BO condition; rs = 0.20) than in the cosmetics use condition (BO+cosmetics condition; rs = 0.15). Ratings of dominance significantly predicted self-assessed dominance in both conditions (rs = 0.34 for natural BO and rs = 0.21 for BO+cosmetics), whereas ratings of extraversion did not predict self-assessed extraversion in either condition. In addition, ratings of body odor attractiveness and pleasantness were significantly lower in natural BO condition than in BO+cosmetics condition, although the intensity of donors’ body odors was similar under both conditions. Our findings suggest that although olfaction seems to contribute to accurate first impression judgments of certain personality traits, cosmetic use can affect assessments of others based on body odor. PMID:27148138

The medial preoptic area is necessary for sexual odor preference, but not sexual solicitation, in female Syrian hamsters

PubMed Central

Martinez, Luis A.; Petrulis, Aras

2013-01-01

Precopulatory behaviors that are preferentially directed towards opposite-sex conspecifics are critical for successful reproduction, particularly in species wherein the sexes live in isolation, such as Syrian hamsters (Mesocricetus auratus). In females, these behaviors include sexual odor preference and vaginal scent marking. The neural regulation of precopulatory behaviors is thought to involve a network of forebrain areas that includes the medial amygdala (MA), the bed nucleus of the stria terminalis (BNST), and the medial preoptic area (MPOA). Although MA and BNST are necessary for sexual odor preference and preferential vaginal marking to male odors, respectively, the role of MPOA in odor-guided female precopulatory behaviors is not well understood. To address this issue, female Syrian hamsters with bilateral, excitotoxic lesions of MPOA (MPOA-X) or sham lesions (SHAM) were tested for sexual odor investigation, scent marking, and lordosis. MPOA-X females did not investigate male odors more than female odors in an odor preference test, indicating that MPOA may be necessary for normal sexual odor preference in female hamsters. This loss of preference cannot be attributed to a sensory deficit, since MPOA-X females successfully discriminated male odors from female odors during an odor discrimination test. Surprisingly, no deficits in vaginal scent marking were observed in MPOA-X females, although these females did exhibit decreased overall levels of flank marking compared to SHAM females. Finally, all MPOA-X females exhibited lordosis appropriately. These results suggest that MPOA plays a critical role in the neural regulation of certain aspects of odor-guided precopulatory behaviors in female Syrian hamsters. PMID:23415835

Anaerobic storage as a pretreatment for enhanced biodegradability of dewatered sewage sludge.

PubMed

Xu, Huacheng; He, Pinjing; Wang, Guanzhao; Shao, Liming; Lee, Duujong

2011-01-01

Dewatered sewage sludge is often stored still before further processing and final disposal. This study showed that anaerobic storage of dewatered sewage sludge could hydrolyze organic matter from the sludge matrix, and increase soluble organic acid content from 90 to 2400 mg/L and soluble organic carbon content from 220 to 1650 mg/L. Correspondingly, the contents of proteins, celluloses and hemicelluloses were reduced by 2-9%. Applying anaerobic storage markedly enhanced the efficiency of the subsequent bio-drying process on stored sludge. Correspondingly, biogas and odor gas were produced immediately after commencing the sludge storage. Anaerobic storage with odor control can be applied as a pretreatment process for dewatered sewage sludge in wastewater treatment plants. Copyright © 2010 Elsevier Ltd. All rights reserved.

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

PubMed Central

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

2013-01-01

Understanding central processing requires precise monitoring of neural activity across populations of identified neurons in the intact brain. Here we used recently-optimized variants of the genetically-encoded calcium sensor GCaMP (GCaMP3 and GCaMPG5G) to image activity among genetically- and anatomically-defined neuronal populations in the olfactory bulb (OB), including two types of GABA-ergic interneurons (periglomerular (PG) and short axon (SA) cells) and OB output neurons (mitral/tufted (MT) cells) projecting to piriform cortex. We first established that changes in neuronal spiking can be accurately related to GCaMP fluorescence changes via a simple quantitative relationship over a large dynamic range. We next used in vivo two-photon imaging from individual neurons and epifluorescence signals reflecting population-level activity to investigate the spatiotemporal representation of odorants across these neuron types in anesthetized and awake mice. Under anesthesia, individual PG and SA cells showed temporally simple responses and little spontaneous activity, while MT cells were spontaneously active and showed diverse temporal responses. At the population level, response patterns of PG, SA and MT cells were surprisingly similar to those imaged from sensory inputs, with shared odorant-specific topography across the dorsal OB and inhalation-coupled temporal dynamics. During wakefulness, PG and SA cell responses increased in magnitude but remained temporally simple while those of MT cells changed to complex spatiotemporal patterns reflecting restricted excitation and widespread inhibition. These results point to multiple circuit elements with distinct roles in transforming odor representations in the OB and provide a framework for further dissecting early olfactory processing using optical and genetic tools. PMID:23516293

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

PubMed Central

Puche, Adam C.; Munger, Steven D.

2016-01-01

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

Odor and odorous chemical emissions from animal buildings: Part 2. Odor emissions

USDA-ARS?s Scientific Manuscript database

This study was an add-on project to the National Air Emissions Monitoring Study (NAEMS) and focused on comprehensive measurement of odor emissions considering variations in seasons, animal types and olfactometry laboratories. Odor emissions from four of 14 NEAMS sites with nine barns/rooms (two dair...

Odor and odorous chemical emissions from animal buildings: Part 6.Odor activity value

USDA-ARS?s Scientific Manuscript database

There is a growing concern with air and odor emissions from agricultural facilities. A supplementary research project was conducted to complement the U.S. National Air Emissions Monitoring Study (NAEMS). The overall goal of the project was to establish odor and chemical emission factors for animal...

[Odor pollution from landfill sites and its control: a review].

PubMed

Hu, Bin; Ding, Ying; Wu, Wei-Xiang; Hu, Bei-Gang; Chen, Ying-Xu

2010-03-01

Landfill sites are the major sources of offensive odor in urban public facilities. With the progress of urbanization and the residents' demands for a higher living environment quality, the odor emission from landfill sites has become a severe pollution problem, and the odor control at landfill sites has been one of the research hotspots. This paper summarized the main components and their concentrations of the odor from landfill sites, and expatiated on the research progress in the in-situ control of the odor. The further research directions in in-situ control of the odor from landfill sites were prospected.

Maternal prefrontal cortex activation by newborn infant odors.

PubMed

Nishitani, Shota; Kuwamoto, Saori; Takahira, Asuka; Miyamura, Tsunetake; Shinohara, Kazuyuki

2014-03-01

Mothers are attracted by infant cues of a variety of different modalities. To clarify the possible neural mechanisms underlying maternal attraction to infant odor cues, we used near-infrared spectroscopy to examine prefrontal cortex (PFC) activity during odor detection tasks in which 19 mothers and 19 nulliparous females (nonmothers) were presented with infant or adult male odors. They were instructed to make a judgment about whether they smelled an odor during each task. We estimated the PFC activity by measuring the relative oxyhemoglobin (oxyHb) concentrations. The results showed that while detecting the infant odors, bilateral PFC activities were increased in mothers but not in nonmothers. In contrast, adult male odors activated the PFC similarly in mothers and nonmothers. These findings suggest that maternal activation of the PFC in response to infant odors explains a part of the neural mechanisms for maternal attraction to infant odors.

Recollective experience in odor recognition: influences of adult age and familiarity.

PubMed

Larsson, Maria; Oberg, Christina; Bäckman, Lars

2006-01-01

We examined recollective experience in odor memory as a function of age, intention to learn, and familiarity. Young and older adults studied a set of familiar and unfamiliar odors with incidental or intentional encoding instructions. At recognition, participants indicated whether their response was based on explicit recollection (remembering), a feeling of familiarity (knowing), or guessing. The results indicated no age-related differences in the distribution of experiential responses for unfamiliar odors. By contrast, for familiar odors the young demonstrated more explicit recollection than the older adults, who produced more "know" and "guess" responses. Intention to learn was unrelated to recollective experience. In addition, the observed age differences in "remember" responses for familiar odors were eliminated when odor naming was statistically controlled. This suggests that age-related deficits in activating specific odor knowledge (i.e., odor names) play an important role for age differences in recollective experience of olfactory information.

Multi-Sensor Integration to Map Odor Distribution for the Detection of Chemical Sources.

PubMed

Gao, Xiang; Acar, Levent

2016-07-04

This paper addresses the problem of mapping odor distribution derived from a chemical source using multi-sensor integration and reasoning system design. Odor localization is the problem of finding the source of an odor or other volatile chemical. Most localization methods require a mobile vehicle to follow an odor plume along its entire path, which is time consuming and may be especially difficult in a cluttered environment. To solve both of the above challenges, this paper proposes a novel algorithm that combines data from odor and anemometer sensors, and combine sensors' data at different positions. Initially, a multi-sensor integration method, together with the path of airflow was used to map the pattern of odor particle movement. Then, more sensors are introduced at specific regions to determine the probable location of the odor source. Finally, the results of odor source location simulation and a real experiment are presented.

Human Odorant Reception in the Common Bed Bug, Cimex lectularius.

PubMed

Liu, Feng; Liu, Nannan

2015-11-02

The common bed bug Cimex lectularius is a temporary ectoparasite on humans and currently resurgent in many developed countries. The ability of bed bugs to detect human odorants in the environment is critical for their host-seeking behavior. This study deciphered the chemical basis of host detection by investigating the neuronal response of olfactory sensilla to 104 human odorants using single sensillum recording and characterized the electro-physiological responses of bed bug odorant receptors to human odorants with the Xenopus expression system. The results showed that the D type of olfactory sensilla play a predominant role in detecting the human odorants tested. Different human odorants elicited different neuronal responses with different firing frequencies and temporal dynamics. Particularly, aldehydes and alcohols are the most effective stimuli in triggering strong response while none of the carboxylic acids showed a strong stimulation. Functional characterization of two bed bug odorant receptors and co-receptors in response to human odorants revealed their specific responses to the aldehyde human odorants. Taken together, the findings of this study not only provide exciting new insights into the human odorant detection of bed bugs, but also offer valuable information for developing new reagents (attractants or repellents) for the bed bug control.

Dense encoding of natural odorants by ensembles of sparsely activated neurons in the olfactory bulb

PubMed Central

Gschwend, Olivier; Beroud, Jonathan; Vincis, Roberto; Rodriguez, Ivan; Carleton, Alan

2016-01-01

Sensory information undergoes substantial transformation along sensory pathways, usually encompassing sparsening of activity. In the olfactory bulb, though natural odorants evoke dense glomerular input maps, mitral and tufted (M/T) cells tuning is considered to be sparse because of highly odor-specific firing rate change. However, experiments used to draw this conclusion were either based on recordings performed in anesthetized preparations or used monomolecular odorants presented at arbitrary concentrations. In this study, we evaluated the lifetime and population sparseness evoked by natural odorants by capturing spike temporal patterning of neuronal assemblies instead of individual M/T tonic activity. Using functional imaging and tetrode recordings in awake mice, we show that natural odorants at their native concentrations are encoded by broad assemblies of M/T cells. While reducing odorant concentrations, we observed a reduced number of activated glomeruli representations and consequently a narrowing of M/T tuning curves. We conclude that natural odorants at their native concentrations recruit M/T cells with phasic rather than tonic activity. When encoding odorants in assemblies, M/T cells carry information about a vast number of odorants (lifetime sparseness). In addition, each natural odorant activates a broad M/T cell assembly (population sparseness). PMID:27824096

Human Odorant Reception in the Common Bed Bug, Cimex lectularius

PubMed Central

Liu, Feng; Liu, Nannan

2015-01-01

The common bed bug Cimex lectularius is a temporary ectoparasite on humans and currently resurgent in many developed countries. The ability of bed bugs to detect human odorants in the environment is critical for their host-seeking behavior. This study deciphered the chemical basis of host detection by investigating the neuronal response of olfactory sensilla to 104 human odorants using single sensillum recording and characterized the electro-physiological responses of bed bug odorant receptors to human odorants with the Xenopus expression system. The results showed that the D type of olfactory sensilla play a predominant role in detecting the human odorants tested. Different human odorants elicited different neuronal responses with different firing frequencies and temporal dynamics. Particularly, aldehydes and alcohols are the most effective stimuli in triggering strong response while none of the carboxylic acids showed a strong stimulation. Functional characterization of two bed bug odorant receptors and co-receptors in response to human odorants revealed their specific responses to the aldehyde human odorants. Taken together, the findings of this study not only provide exciting new insights into the human odorant detection of bed bugs, but also offer valuable information for developing new reagents (attractants or repellents) for the bed bug control. PMID:26522967

Odor Perception by Dogs: Evaluating Two Training Approaches for Odor Learning of Sniffer Dogs.

PubMed

Fischer-Tenhagen, Carola; Johnen, Dorothea; Heuwieser, Wolfgang; Becker, Roland; Schallschmidt, Kristin; Nehls, Irene

2017-06-01

In this study, a standardized experimental set-up with various combinations of herbs as odor sources was designed. Two training approaches for sniffer dogs were compared; first, training with a pure reference odor, and second, training with a variety of odor mixtures with the target odor as a common denominator. The ability of the dogs to identify the target odor in a new context was tested. Six different herbs (basil, St. John's wort, dandelion, marjoram, parsley, ribwort) were chosen to produce reference materials in various mixtures with (positive) and without (negative) chamomile as the target odor source. The dogs were trained to show 1 of 2 different behaviors, 1 for the positive, and 1 for the negative sample as a yes/no task. Tests were double blind with one sample presented at a time. In both training approaches, dogs were able to detect chamomile as the target odor in any presented mixture with an average sensitivity of 72% and a specificity of 84%. Dogs trained with odor mixture containing the target odor had more correct indications in the transfer task. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Structure-odor relationships of linalool, linalyl acetate and their corresponding oxygenated derivatives

NASA Astrophysics Data System (ADS)

Elsharif, Shaimaa; Banerjee, Ashutosh; Buettner, Andrea

2015-10-01

Linalool 1 is an odorant that is commonly perceived as having a pleasant odor, but is also known to elicit physiological effects such as inducing calmness and enhancing sleep. However, no comprehensive studies are at hand to show which structural features are responsible for these prominent effects. Therefore, a total of six oxygenated derivatives were synthesized from both 1 and linalyl acetate 2, and were tested for their odor qualities and relative odor thresholds (OTs) in air. Linalool was found to be the most potent odorant among the investigated compounds, with an average OT of 3.2 ng/L, while the 8-hydroxylinalool derivative was the least odorous compound with an OT of 160 ng/L; 8-carboxylinalool was found to be odorless. The odorant 8-oxolinalyl acetate, which has very similar odor properties to linalool, was the most potent odorant besides linalool, exhibiting an OT of 5.9 ng/L. By comparison, 8-carboxylinalyl acetate had a similar OT (6.1 ng/L) as its corresponding 8-oxo derivative but exhibited divergent odor properties (fatty, greasy, musty). Overall, oxygenation on carbon 8 had a substantial effect on the aroma profiles of structural derivatives of linalool and linalyl acetate.

Identification of pleasant, neutral, and unpleasant odors in schizophrenia

PubMed Central

Kamath, Vidyulata; Turetsky, Bruce I.; Moberg, Paul J.

2010-01-01

Recent work on odor hedonics in schizophrenia has indicated that patients display abnormalities in hedonic judgments of odors in comparison to healthy comparison participants. In the current study, identification accuracy for pleasant, neutral, and unpleasant odors in individuals with schizophrenia and healthy controls was examined. Thirty-three schizophrenia patients (63% male) and thirty-one healthy volunteers (65% male) were recruited. The groups were well matched on age, sex, and smoking status. Participants were administered the University of Pennsylvania Smell Identification Test, which was subsequently divided into 16 pleasant, 15 neutral, and 9 unpleasant items. Analysis of identification z-scores for pleasant, neutral, and unpleasant odors revealed a significant diagnosis by valence interaction. Post-hoc analysis revealed that schizophrenia participants made more identification errors on pleasant and neutral odors compared to healthy controls, with no differences observed for unpleasant odors. No effect was seen for sex. The findings from the current investigation suggest that odor identification accuracy in patients is influenced by odor valence. This pattern of results parallels a growing body of literature indicating that patients display aberrant pleasantness ratings for pleasant odors and highlights the need for additional research on the influence of odor valence on olfactory identification performance in individuals with schizophrenia. PMID:21239063

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

PubMed

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

2016-01-01

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

Characterization of the Key Aroma Volatile Compounds in Cranberry (Vaccinium macrocarpon Ait.) Using Gas Chromatography-Olfactometry (GC-O) and Odor Activity Value (OAV).

PubMed

Zhu, JianCai; Chen, Feng; Wang, LingYing; Niu, YunWei; Chen, HeXing; Wang, HongLin; Xiao, ZuoBing

2016-06-22

The volatile compounds of cranberries obtained from four cultivars (Early Black, Y1; Howes, Y2; Searles, Y3; and McFarlin, Y4) were analyzed by gas chromatography-olfactometry (GC-O), gas chromatography-mass spectrometry (GC-MS), and GC-flame photometric detection (FPD). The result presented that a total of thirty-three, thirty-four, thirty-four, and thirty-six odor-active compounds were identified by GC-O in the Y1, Y2, Y3, and Y4, respectively. In addition, twenty-two, twenty-two, thirty, and twenty-seven quantified compounds were demonstrated as important odorants according to odor activity values (OAVs > 1). Among these compounds, hexanal (OAV: 27-60), pentanal (OAV: 31-51), (E)-2-heptenal (OAV: 17-66), (E)-2-hexenal (OAV: 18-63), (E)-2-octenal (OAV: 10-28), (E)-2-nonenal (OAV: 8-77), ethyl 2-methylbutyrate (OAV: 10-33), β-ionone (OAV: 8-73), 2-methylbutyric acid (OAV: 18-37), and octanal (OAV: 4-24) contributed greatly to the aroma of cranberry. Partial least-squares regression (PLSR) was used to process the mean data accumulated from sensory evaluation by the panelists, odor-active aroma compounds (OAVs > 1), and samples. Sample Y3 was highly correlated with the sensory descriptors "floral" and "fruity". Sample Y4 was greatly related to the sensory descriptors "mellow" and "green and grass". Finally, an aroma reconstitution (Model A) was prepared by mixing the odor-active aroma compounds (OAVs > 1) based on their measured concentrations in the Y1 sample, indicating that the aroma profile of the reconstitution was pretty similar to that of the original sample.

Lack of TRPM5-Expressing Microvillous Cells in Mouse Main Olfactory Epithelium Leads to Impaired Odor-Evoked Responses and Olfactory-Guided Behavior in a Challenging Chemical Environment

PubMed Central

Lemons, Kayla; Aoudé, Imad; Ogura, Tatsuya; Mbonu, Kenechukwu; Matsumoto, Ichiro; Arakawa, Hiroyuki

2017-01-01

The mammalian main olfactory epithelium (MOE) modifies its activities in response to changes in the chemical environment. This process is essential for maintaining the functions of the olfactory system and the upper airway. However, mechanisms involved in this functional maintenance, especially those occurring via paracrine regulatory pathways within the multicellular MOE, are poorly understood. Previously, a population of non-neuronal, transient receptor potential M5-expressing microvillous cells (TRPM5-MCs) was identified in the MOE, and the initial characterization of these cells showed that they are cholinergic and responsive to various xenobiotics including odorants at high concentrations. Here, we investigated the role of TRPM5-MCs in maintaining olfactory function using transcription factor Skn-1a knockout (Skn-1a-/-) mice, which lack TRPM5-MCs in the MOE. Under our standard housing conditions, Skn-1a-/- mice do not differ significantly from control mice in odor-evoked electro-olfactogram (EOG) responses and olfactory-guided behaviors, including finding buried food and preference reactions to socially and sexually relevant odors. However, after a 2-wk exposure to high-concentration odor chemicals and chitin powder, Skn-1a-/- mice exhibited a significant reduction in their odor and pheromone-evoked EOG responses. Consequently, their olfactory-guided behaviors were impaired compared with vehicle-exposed Skn-1a-/- mice. Conversely, the chemical exposure did not induce significant changes in the EOG responses and olfactory behaviors of control mice. Therefore, our physiological and behavioral results indicate that TRPM5-MCs play a protective role in maintaining the olfactory function of the MOE. PMID:28612045

Circuit oscillations in odor perception and memory.

PubMed

Kay, Leslie M

2014-01-01

Olfactory system neural oscillations as seen in the local field potential have been studied for many decades. Recent research has shown that there is a functional role for the most studied gamma oscillations (40-100Hz in rats and mice, and 20Hz in insects), without which fine odor discrimination is poor. When these oscillations are increased artificially, fine discrimination is increased, and when rats learn difficult and highly overlapping odor discriminations, gamma is increased in power. Because of the depth of study on this oscillation, it is possible to point to specific changes in neural firing patterns as represented by the increase in gamma oscillation amplitude. However, we know far less about the mechanisms governing beta oscillations (15-30Hz in rats and mice), which are best associated with associative learning of responses to odor stimuli. These oscillations engage every part of the olfactory system that has so far been tested, plus the hippocampus, and the beta oscillation frequency band is the one that is most reliably coherent with other regions during odor processing. Respiratory oscillations overlapping with the theta frequency band (2-12Hz) are associated with odor sniffing and normal breathing in rats. They also show coupling in some circumstances between olfactory areas and rare coupling between the hippocampus and olfactory bulb. The latter occur in specific learning conditions in which coherence strength is negatively or positively correlated with performance, depending on the task. There is still much to learn about the role of neural oscillations in learning and memory, but techniques that have been brought to bear on gamma oscillations (current source density, computational modeling, slice physiology, behavioral studies) should deliver much needed knowledge of these events. © 2014 Elsevier B.V. All rights reserved.

How the brain assigns a neural tag to arbitrary points in a high-dimensional space

NASA Astrophysics Data System (ADS)

Stevens, Charles

Brains in almost all organisms need to deal with very complex stimuli. For example, most mammals are very good at face recognition, and faces are very complex objects indeed. For example, modern face recognition software represents a face as a point in a 10,000 dimensional space. Every human must be able to learn to recognize any of the 7 billion faces in the world, and can recognize familiar faces after a display of the face is viewed for only a few hundred milliseconds. Because we do not understand how faces are assigned locations in a high-dimensional space by the brain, attacking the problem of how face recognition is accomplished is very difficult. But a much easier problem of the same sort can be studied for odor recognition. For the mouse, each odor is assigned a point in a 1000 dimensional space, and the fruit fly assigns any odor a location in only a 50 dimensional space. A fly has about 50 distinct types of odorant receptor neurons (ORNs), each of which produce nerve impulses at a specific rate for each different odor. This pattern of firing produced across 50 ORNs is called `a combinatorial odor code', and this code assigns every odor a point in a 50 dimensional space that is used to identify the odor. In order to learn the odor, the brain must alter the strength of synapses. The combinatorial code cannot itself by used to change synaptic strength because all odors use same neurons to form the code, and so all synapses would be changed for any odor and the odors could not be distinguished. In order to learn an odor, the brain must assign a set of neurons - the odor tag - that have the property that these neurons (1) should make use of all of the information available about the odor, and (2) insure that any two tags overlap as little as possible (so one odor does not modify synapses used by other odors). In the talk, I will explain how the olfactory system of both the fruit fly and the mouse produce a tag for each odor that has these two properties. Supported by NSF.

Regulation of sexual odor preference by sex steroids in the posterodorsal medial amygdala in female rats.

PubMed

Fujiwara, Masaya; Nitta, Asano; Chiba, Atsuhiko

2016-06-01

Our previous study in male rats demonstrated that bilateral administration of flutamide, an androgen receptor (AR) antagonist, into the posterodorsal medial amygdala (MePD) increased the time sniffing male odors to as high as that sniffing estrous odors, eliminating the preference for estrous odors over male odors. This made us speculate that under blockade of AR in the MePD, testosterone-derived estrogen acting on the same brain region arouses interest in male odors which is otherwise suppressed by concomitant action of androgen. In cyclic female rats, endogenous androgen has been thought to be involved in inhibitory regulation of estrogen-activated sexual behavior. Thus, in the present study, we investigated the possibility that in female rats the arousal of interest in male odors is also normally regulated by both estrogen and androgen acting on the MePD, as predicted by our previous study in male rats. Implantation of either the estrogen receptor blocker tamoxifen (TX) or a non-aromatizable androgen 5α-dihydrotestosterone (DHT) into the MePD of ovariectomized, estrogen-primed female rats eliminated preference for male odors over estrous odors by significantly decreasing the time sniffing male odors to as low as that sniffing estrous odors. The subsequent odor discrimination tests confirmed that the DHT and TX administration did not impair the ability to discriminate between male and estrous odors. These results suggest that in estrous female rats estrogen action in the MePD plays critical roles in the expression of the preference for male odors while androgen action in the same brain region interferes with the estrogen action. Copyright © 2016 Elsevier Inc. All rights reserved.

Odor-context effects in free recall after a short retention interval: a new methodology for controlling adaptation.

PubMed

Isarida, Takeo; Sakai, Tetsuya; Kubota, Takayuki; Koga, Miho; Katayama, Yu; Isarida, Toshiko K

2014-04-01

The present study investigated context effects of incidental odors in free recall after a short retention interval (5 min). With a short retention interval, the results are not confounded by extraneous odors or encounters with the experimental odor and possible rehearsal during a long retention interval. A short study time condition (4 s per item), predicted not to be affected by adaptation to the odor, and a long study time condition (8 s per item) were used. Additionally, we introduced a new method for recovery from adaptation, where a dissimilar odor was briefly presented at the beginning of the retention interval, and we demonstrated the effectiveness of this technique. An incidental learning paradigm was used to prevent overshadowing from confounding the results. In three experiments, undergraduates (N = 200) incidentally studied words presented one-by-one and received a free recall test. Two pairs of odors and a third odor having different semantic-differential characteristics were selected from 14 familiar odors. One of the odors was presented during encoding, and during the test, the same odor (same-context condition) or the other odor within the pair (different-context condition) was presented. Without using a recovery-from-adaptation method, a significant odor-context effect appeared in the 4-s/item condition, but not in the 8-s/item condition. Using the recovery-from-adaptation method, context effects were found for both the 8- and the 4-s/item conditions. The size of the recovered odor-context effect did not change with study time. There were no serial position effects. Implications of the present findings are discussed.

A CO2-Free Synthetic Host-Odor Mixture That Attracts and Captures Triatomines: Effect of Emitted Odorant Ratios.

PubMed

Guidobaldi, F; Guerenstein, P G

2016-07-01

Triatomines, vectors of Chagas Disease, are hematophagous insects. Efforts have been made to develop synthetic attractants based on vertebrate odor-to lure them into traps. However, because those lures are not practical or have low capture efficiency, they are not in use in control programs. Therefore, more work is needed to reach a practical and efficient odor lure. Recently, a three-component, CO 2 -free, synthetic blend of vertebrate odor (consisting of ammonia, l-(+)-lactic acid, and hexanoic acid), known as Sweetscent (Biogents AG, Regensburg, Germany), was shown to attract and capture triatomines in the laboratory. In this study, using a trap olfactometer and an odor blend with constituents similar to those of Sweetscent (delivered from low-density polyethylene sachets) we found that the odorant ratios of the mixtures have a strong effect in the capture of triatomines. The blend with the most efficient combination of odorant ratios evoked ca. 81% capture in two relevant triatomine species. In the case of the most effective odor mixtures, we measured the odor mass emission for the three components of the mixture and therefore were able to estimate the odorant ratios emitted that were responsible for such a high capture performance. Thus, in those mixtures, pentanoic acid was the main component (ca. 65 %) followed by ammonia (ca. 28%) and, l(+)-lactic acid (ca. 7 %). Our results are encouraging as efficient, practical, and cheap odor baits to trap triatomines in the field would be within reach. The odor-delivery system used should be improved to increase stability of odor emission. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

The medial preoptic area is necessary for sexual odor preference, but not sexual solicitation, in female Syrian hamsters.

PubMed

Martinez, Luis A; Petrulis, Aras

2013-04-01

Precopulatory behaviors that are preferentially directed towards opposite-sex conspecifics are critical for successful reproduction, particularly in species wherein the sexes live in isolation, such as Syrian hamsters (Mesocricetus auratus). In females, these behaviors include sexual odor preference and vaginal scent marking. The neural regulation of precopulatory behaviors is thought to involve a network of forebrain areas that includes the medial amygdala (MA), the bed nucleus of the stria terminalis (BNST), and the medial preoptic area (MPOA). Although MA and BNST are necessary for sexual odor preference and preferential vaginal marking to male odors, respectively, the role of MPOA in odor-guided female precopulatory behaviors is not well understood. To address this issue, female Syrian hamsters with bilateral, excitotoxic lesions of MPOA (MPOA-X) or sham lesions (SHAM) were tested for sexual odor investigation, scent marking, and lordosis. MPOA-X females did not investigate male odors more than female odors in an odor preference test, indicating that MPOA may be necessary for normal sexual odor preference in female hamsters. This loss of preference cannot be attributed to a sensory deficit, since MPOA-X females successfully discriminated male odors from female odors during an odor discrimination test. Surprisingly, no deficits in vaginal scent marking were observed in MPOA-X females, although these females did exhibit decreased overall levels of flank marking compared to SHAM females. Finally, all MPOA-X females exhibited lordosis appropriately. These results suggest that MPOA plays a critical role in the neural regulation of certain aspects of odor-guided precopulatory behaviors in female Syrian hamsters. Copyright © 2013 Elsevier Inc. All rights reserved.

The smell of age: perception and discrimination of body odors of different ages.

PubMed

Mitro, Susanna; Gordon, Amy R; Olsson, Mats J; Lundström, Johan N

2012-01-01

Our natural body odor goes through several stages of age-dependent changes in chemical composition as we grow older. Similar changes have been reported for several animal species and are thought to facilitate age discrimination of an individual based on body odors, alone. We sought to determine whether humans are able to discriminate between body odor of humans of different ages. Body odors were sampled from three distinct age groups: Young (20-30 years old), Middle-age (45-55), and Old-age (75-95) individuals. Perceptual ratings and age discrimination performance were assessed in 41 young participants. There were significant differences in ratings of both intensity and pleasantness, where body odors from the Old-age group were rated as less intense and less unpleasant than body odors originating from Young and Middle-age donors. Participants were able to discriminate between age categories, with body odor from Old-age donors mediating the effect also after removing variance explained by intensity differences. Similarly, participants were able to correctly assign age labels to body odors originating from Old-age donors but not to body odors originating from other age groups. This experiment suggests that, akin to other animals, humans are able to discriminate age based on body odor alone and that this effect is mediated mainly by body odors emitted by individuals of old age.

The Smell of Age: Perception and Discrimination of Body Odors of Different Ages

PubMed Central

Mitro, Susanna; Gordon, Amy R.; Olsson, Mats J.; Lundström, Johan N.

2012-01-01

Our natural body odor goes through several stages of age-dependent changes in chemical composition as we grow older. Similar changes have been reported for several animal species and are thought to facilitate age discrimination of an individual based on body odors, alone. We sought to determine whether humans are able to discriminate between body odor of humans of different ages. Body odors were sampled from three distinct age groups: Young (20–30 years old), Middle-age (45–55), and Old-age (75–95) individuals. Perceptual ratings and age discrimination performance were assessed in 41 young participants. There were significant differences in ratings of both intensity and pleasantness, where body odors from the Old-age group were rated as less intense and less unpleasant than body odors originating from Young and Middle-age donors. Participants were able to discriminate between age categories, with body odor from Old-age donors mediating the effect also after removing variance explained by intensity differences. Similarly, participants were able to correctly assign age labels to body odors originating from Old-age donors but not to body odors originating from other age groups. This experiment suggests that, akin to other animals, humans are able to discriminate age based on body odor alone and that this effect is mediated mainly by body odors emitted by individuals of old age. PMID:22666457

Odor and odorous chemical emissions from animal buildings: Part 2 - odor emissions

USDA-ARS?s Scientific Manuscript database

This study was an add-on project to the National Air Emissions Monitoring Study (NAEMS) and focused on comprehensive measurement of odor emissions. Odor emissions from two animal species (dairy and swine) from four sites with nine barns/rooms (two dairy barns in Wisconsin, two dairy barns and two sw...

Insights into structural features determining odorant affinities to honey bee odorant binding protein 14.

PubMed

Schwaighofer, Andreas; Pechlaner, Maria; Oostenbrink, Chris; Kotlowski, Caroline; Araman, Can; Mastrogiacomo, Rosa; Pelosi, Paolo; Knoll, Wolfgang; Nowak, Christoph; Larisika, Melanie

2014-04-18

Molecular interactions between odorants and odorant binding proteins (OBPs) are of major importance for understanding the principles of selectivity of OBPs towards the wide range of semiochemicals. It is largely unknown on a structural basis, how an OBP binds and discriminates between odorant molecules. Here we examine this aspect in greater detail by comparing the C-minus OBP14 of the honey bee (Apis mellifera L.) to a mutant form of the protein that comprises the third disulfide bond lacking in C-minus OBPs. Affinities of structurally analogous odorants featuring an aromatic phenol group with different side chains were assessed based on changes of the thermal stability of the protein upon odorant binding monitored by circular dichroism spectroscopy. Our results indicate a tendency that odorants show higher affinity to the wild-type OBP suggesting that the introduced rigidity in the mutant protein has a negative effect on odorant binding. Furthermore, we show that OBP14 stability is very sensitive to the position and type of functional groups in the odorant. Copyright © 2014 Elsevier Inc. All rights reserved.

Effect of experience with pine (Pituophis melanoleucus) and king (Lampropeltis getulus) snake odors on Y-maze behavior of pine snake hatchlings.

PubMed

Burger, J; Boarman, W; Kurzava, L; Gochfeld, M

1991-01-01

The abilities of hatchling pine snakes (Pituophis melanoleucus) and king snakes (Lampropeltis getulus) to discriminate the chemical trails of pine and king snakes was investigated inY-maze experiments. Pine snakes were housed for 17 days either with shavings impregnated with pine snake odor, king snake odor, or no odor to test for the effect of experience on choice. Both pine and king snake hatchlings entered the arm with the pine snake odor and did not enter the arm with the king snake odor. The data support the hypothesis that hatchlings of both species can distinguish conspecific odors from other odors and that our manipulation of previous experience was without effect for pine snake hatchlings.

Predicting the response of olfactory sensory neurons to odor mixtures from single odor response

NASA Astrophysics Data System (ADS)

Marasco, Addolorata; de Paris, Alessandro; Migliore, Michele

2016-04-01

The response of olfactory receptor neurons to odor mixtures is not well understood. Here, using experimental constraints, we investigate the mathematical structure of the odor response space and its consequences. The analysis suggests that the odor response space is 3-dimensional, and predicts that the dose-response curve of an odor receptor can be obtained, in most cases, from three primary components with specific properties. This opens the way to an objective procedure to obtain specific olfactory receptor responses by manipulating mixtures in a mathematically predictable manner. This result is general and applies, independently of the number of odor components, to any olfactory sensory neuron type with a response curve that can be represented as a sigmoidal function of the odor concentration.

Structure-Odor Correlations in Homologous Series of Mercapto Furans and Mercapto Thiophenes Synthesized by Changing the Structural Motifs of the Key Coffee Odorant Furan-2-ylmethanethiol.

PubMed

Schoenauer, Sebastian; Schieberle, Peter

2018-04-25

Furan-2-ylmethanethiol (2-furfurylthiol; 2-FFT, 1) is long-known as a key odorant in roast and ground coffee and was also previously identified in a wide range of thermally treated foods such as meat, bread, and roasted sesame seeds. Its unique coffee-like odor quality elicited at very low concentrations, and the fact that only a very few compounds showing a similar structure have previously been described in foods make 1 a suitable candidate for structure-odor activity studies. To gain insight into the structural features needed to evoke a coffee-like odor at low concentrations, 46 heterocyclic mercaptans and thio ethers were synthesized, 32 of them for the first time, and their odor qualities and odor thresholds were determined. A movement of the mercapto group to the 3-position kept the coffee-like aroma but led to an increase in odor threshold. A separation of the thiol group from the furan ring by an elongation of the carbon side chain caused a loss of the coffee-like odor and also led to an increase in odor thresholds, especially for ω-(furan-2-yl)alkane-1-thiols with six or seven carbon atoms in the side chain. A displacement of the furan ring by a thiophene ring had no significant influence on the odor properties of most of the compounds studied, but the newly synthesized longer-chain 1-(furan-2-yl)- and 1-(thiophene-2-yl)alkane-1-thiols elicited interesting passion fruit-like scents. In total, only 4 out of the 46 compounds also showed a coffee-like odor quality like 1, but none showed a lower odor threshold. Besides the odor attributes, also retention indices, mass spectra, and NMR data of the synthesized compounds were elaborated, which are helpful in possible future identification of these compounds in trace levels in foods or other materials.

Keeping their distance? Odor response patterns along the concentration range

PubMed Central

Strauch, Martin; Ditzen, Mathias; Galizia, C. Giovanni

2012-01-01

We investigate the interplay of odor identity and concentration coding in the antennal lobe (AL) of the honeybee Apis mellifera. In this primary olfactory center of the honeybee brain, odors are encoded by the spatio-temporal response patterns of olfactory glomeruli. With rising odor concentration, further glomerular responses are recruited into the patterns, which affects distances between the patterns. Based on calcium-imaging recordings, we found that such pattern broadening renders distances between glomerular response patterns closer to chemical distances between the corresponding odor molecules. Our results offer an explanation for the honeybee's improved odor discrimination performance at higher odor concentrations. PMID:23087621

Sensory Characterization of Odors in Used Disposable Absorbent Incontinence Products

PubMed Central

Widén, Heléne; Forsgren-Brusk, Ulla; Hall, Gunnar

2017-01-01

PURPOSE: The objectives of this study were to characterize the odors of used incontinence products by descriptive analysis and to define attributes to be used in the analysis. A further objective was to investigate to what extent the odor profiles of used incontinence products differed from each other and, if possible, to group these profiles into classes. SUBJECTS AND SETTING: Used incontinence products were collected from 14 residents with urinary incontinence living in geriatric nursing homes in the Gothenburg area, Sweden. METHODS: Pieces were cut from the wet area of used incontinence products. They were placed in glass bottles and kept frozen until odor analysis was completed. A trained panel consisting of 8 judges experienced in this area of investigation defined terminology for odor attributes. The intensities of these attributes in the used products were determined by descriptive odor analysis. Data were analyzed both by analysis of variance (ANOVA) followed by the Tukey post hoc test and by principal component analysis and cluster analysis. RESULTS: An odor wheel, with 10 descriptive attributes, was developed. The total odor intensity, and the intensities of the attributes, varied considerably between different, used incontinence products. The typical odors varied from “sweetish” to “urinal,” “ammonia,” and “smoked.” Cluster analysis showed that the used products, based on the quantitative odor data, could be divided into 5 odor classes with different profiles. CONCLUSIONS: The used products varied considerably in odor character and intensity. Findings suggest that odors in used absorptive products are caused by different types of compounds that may vary in concentration. PMID:28328646

The spatial and temporal patterns of odors sampled by lobsters and crabs in a turbulent plume.

PubMed

Reidenbach, Matthew A; Koehl, M A R

2011-09-15

Odors are dispersed across aquatic habitats by turbulent water flow as filamentous, intermittent plumes. Many crustaceans sniff (take discrete samples of ambient water and the odors it carries) by flicking their olfactory antennules. We used planar laser-induced fluorescence to investigate how flicking antennules of different morphologies (long antennules of spiny lobsters, Panulirus argus; short antennules of blue crabs, Callinectes sapidus) sample fluctuating odor signals at different positions in a turbulent odor plume in a flume to determine whether the patterns of concentrations captured can provide information about an animal's position relative to the odor source. Lobster antennules intercept odors during a greater percentage of flicks and encounter higher peak concentrations than do crab antennules, but because crabs flick at higher frequency, the duration of odor-free gaps between encountered odor pulses is similar. For flicking antennules there were longer time gaps between odor encounters as the downstream distance to the odor source decreases, but shorter gaps along the plume centerline than near the edge. In contrast to the case for antennule flicking, almost all odor-free gaps were <500 ms at all positions in the plume if concentration was measured continuously at the same height as the antennules. Variance in concentration is lower and mean concentration is greater near the substratum, where leg chemosensors continuously sample the plume, than in the water where antennules sniff. Concentrations sampled by legs increase as an animal nears an odor source, but decrease for antennules. Both legs and antennules encounter higher concentrations near the centerline than at the edge of the plume.

Pleasantness, familiarity, and identification of spice odors are interrelated and enhanced by consumption of herbs and food neophilia.

PubMed

Knaapila, Antti; Laaksonen, Oskar; Virtanen, Markus; Yang, Baoru; Lagström, Hanna; Sandell, Mari

2017-02-01

The primary dimension of odor is pleasantness, which is associated with a multitude of factors. We investigated how the pleasantness, familiarity, and identification of spice odors were associated with each other and with the use of the respective spice, overall use of herbs, and level of food neophobia. A total of 126 adults (93 women, 33 men; age 25-61 years, mean 39 years) rated the odors from 12 spices (oregano, anise, rosemary, mint, caraway, sage, thyme, cinnamon, fennel, marjoram, garlic, and clove) for pleasantness and familiarity, and completed a multiple-choice odor identification. Data on the use of specific spices, overall use of herbs, and Food Neophobia Scale score were collected using an online questionnaire. Familiar odors were mostly rated as pleasant (except garlic), whereas unfamiliar odors were rated as neutral (r = 0.63). We observed consistent and often significant trends that suggested the odor pleasantness and familiarity were positively associated with the correct odor identification, consumption of the respective spice, overall use of herbs, and food neophilia. Our results suggest that knowledge acquisition through repetitive exposure to spice odor with active attention may gradually increase the odor pleasantness within the framework set by the chemical characteristics of the aroma compound. Copyright © 2016 Elsevier Ltd. All rights reserved.

Identification of pleasant, neutral, and unpleasant odors in schizophrenia.

PubMed

Kamath, Vidyulata; Turetsky, Bruce I; Moberg, Paul J

2011-05-15

Recent work on odor hedonics in schizophrenia has indicated that patients display abnormalities in hedonic judgments of odors in comparison to healthy comparison participants. In the current study, identification accuracy for pleasant, neutral, and unpleasant odors in individuals with schizophrenia and healthy controls was examined. Thirty-three schizophrenia patients (63% male) and thirty-one healthy volunteers (65% male) were recruited. The groups were well matched on age, sex, and smoking status. Participants were administered the University of Pennsylvania Smell Identification Test, which was subsequently divided into 16 pleasant, 15 neutral, and 9 unpleasant items. Analysis of identification z-scores for pleasant, neutral, and unpleasant odors revealed a significant diagnosis by valence interaction. Post-hoc analysis revealed that schizophrenia participants made more identification errors on pleasant and neutral odors compared to healthy controls, with no differences observed for unpleasant odors. No effect was seen for sex. The findings from the current investigation suggest that odor identification accuracy in patients is influenced by odor valence. This pattern of results parallels a growing body of literature indicating that patients display aberrant pleasantness ratings for pleasant odors and highlights the need for additional research on the influence of odor valence on olfactory identification performance in individuals with schizophrenia. Copyright © 2010 Elsevier Ltd. All rights reserved.

Red junglefowl have individual body odors.

PubMed

Karlsson, Anna-Carin; Jensen, Per; Elgland, Mathias; Laur, Katriann; Fyrner, Timmy; Konradsson, Peter; Laska, Matthias

2010-05-01

Olfaction may play an important role in regulating bird behavior, and has been suggested to be involved in feather-pecking. We investigated possible differences in the body odors of red junglefowl females by using an automated olfactometer which assessed the ability of trained mice to discriminate between the odors of uropygial gland secretions (the main carrier of potential individual odors in chickens) of six feather-pecked and six non-pecked birds. All mice were clearly able to discriminate between all individual red junglefowl odors, showing that each bird has an individual body odor. We analyzed whether it was more difficult to discriminate between the odors of two feather-pecked, or two non-pecked birds, than it was to discriminate between the odors of two randomly selected birds. This was not the case, suggesting that feather-pecked birds did not share a common odor signature. Analyses using gas chromatography and mass spectrometry showed that the composition of aliphatic carboxylic acids in uropygial gland secretions differed consistently between individuals. However, chemical composition did not vary according to feather-pecking status. We conclude that red junglefowl have individual body odors which appear to be largely based on differences in the relative abundance of aliphatic carboxylic acids, but there is no evidence of systematic differences between the body odors of pecked and non-pecked birds.

A computational study of odorant transport and deposition in the canine nasal cavity: implications for olfaction.

PubMed

Lawson, M J; Craven, B A; Paterson, E G; Settles, G S

2012-07-01

Olfaction begins when an animal draws odorant-laden air into its nasal cavity by sniffing, thus transporting odorant molecules from the external environment to olfactory receptor neurons (ORNs) in the sensory region of the nose. In the dog and other macrosmatic mammals, ORNs are relegated to a recess in the rear of the nasal cavity that is comprised of a labyrinth of scroll-like airways. Evidence from recent studies suggests that nasal airflow patterns enhance olfactory sensitivity by efficiently delivering odorant molecules to the olfactory recess. Here, we simulate odorant transport and deposition during steady inspiration in an anatomically correct reconstructed model of the canine nasal cavity. Our simulations show that highly soluble odorants are deposited in the front of the olfactory recess along the dorsal meatus and nasal septum, whereas moderately soluble and insoluble odorants are more uniformly deposited throughout the entire olfactory recess. These results demonstrate that odorant deposition patterns correspond with the anatomical organization of ORNs in the olfactory recess. Specifically, ORNs that are sensitive to a particular class of odorants are located in regions where that class of odorants is deposited. The correlation of odorant deposition patterns with the anatomical organization of ORNs may partially explain macrosmia in the dog and other keen-scented species.

Health effects of indoor odorants.

PubMed Central

Cone, J E; Shusterman, D

1991-01-01

People assess the quality of the air indoors primarily on the basis of its odors and on their perception of associated health risk. The major current contributors to indoor odorants are human occupant odors (body odor), environmental tobacco smoke, volatile building materials, bio-odorants (particularly mold and animal-derived materials), air fresheners, deodorants, and perfumes. These are most often present as complex mixtures, making measurement of the total odorant problem difficult. There is no current method of measuring human body odor, other than by human panel studies of expert judges of air quality. Human body odors have been quantitated in terms of the "olf" which is the amount of air pollution produced by the average person. Another quantitative unit of odorants is the "decipol," which is the perceived level of pollution produced by the average human ventilated by 10 L/sec of unpolluted air or its equivalent level of dissatisfaction from nonhuman air pollutants. The standard regulatory approach, focusing on individual constituents or chemicals, is not likely to be successful in adequately controlling odorants in indoor air. Besides the current approach of setting minimum ventilation standards to prevent health effects due to indoor air pollution, a standard based on the olf or decipol unit might be more efficacious as well as simpler to measure. PMID:1821378

Glomerular Activity Patterns Evoked by Natural Odor Objects in the Rat Olfactory Bulb Are Related to Patterns Evoked by Major Odorant Components

PubMed Central

Johnson, Brett A.; Ong, Joan; Leon, Michael

2014-01-01

To determine how responses evoked by natural odorant mixtures compare to responses evoked by individual odorant chemicals, we mapped 2-deoxyglucose uptake during exposures to vapors arising from a variety of odor objects that may be important to rodents in the wild. We studied 21 distinct natural odor stimuli ranging from possible food sources such as fruits, vegetables, and meats to environmental odor objects such as grass, herbs, and tree leaves. The natural odor objects evoked robust and surprisingly focal patterns of 2-deoxyglucose uptake involving clusters of neighboring glomeruli, thereby resembling patterns evoked by pure chemicals. Overall, the patterns were significantly related to patterns evoked by monomolecular odorant components that had been studied previously. Object patterns also were significantly related to the molecular features present in the mixture components. Despite these overall relationships, there were individual examples of object patterns that were simpler than might have been predicted given the multiplicity of components present in the vapors. In these cases, the object patterns lacked certain responses evoked by their major odorant mixture components. These data suggest the possibility of mixture response interactions and provide a foundation for understanding the neural coding of natural odor stimuli. PMID:20187145

Age-Related Changes in Children's Hedonic Response to Male Body Odor.

ERIC Educational Resources Information Center

Stevenson, Richard J.; Repacholi, Betty M.

2003-01-01

Examined children's and adolescents' ability to identify male sweat and other odors and their rating of odors for liking. Found that only female adolescents could identify and disliked male sweat. When cued about odor identity, both male and female adolescents disliked male sweat more than children. Concluded that dislike for male sweat odor may…

9 CFR 311.20 - Sexual odor of swine.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 9 Animals and Animal Products 2 2014-01-01 2014-01-01 false Sexual odor of swine. 311.20 Section... Sexual odor of swine. (a) Carcasses of swine which give off a pronounced sexual odor shall be condemned. (b) The meat of swine carcasses which give off a sexual odor less than pronounced may be passed for...

9 CFR 311.20 - Sexual odor of swine.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 9 Animals and Animal Products 2 2012-01-01 2012-01-01 false Sexual odor of swine. 311.20 Section... Sexual odor of swine. (a) Carcasses of swine which give off a pronounced sexual odor shall be condemned. (b) The meat of swine carcasses which give off a sexual odor less than pronounced may be passed for...

9 CFR 311.20 - Sexual odor of swine.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 9 Animals and Animal Products 2 2011-01-01 2011-01-01 false Sexual odor of swine. 311.20 Section... Sexual odor of swine. (a) Carcasses of swine which give off a pronounced sexual odor shall be condemned. (b) The meat of swine carcasses which give off a sexual odor less than pronounced may be passed for...

9 CFR 311.20 - Sexual odor of swine.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 9 Animals and Animal Products 2 2013-01-01 2013-01-01 false Sexual odor of swine. 311.20 Section... Sexual odor of swine. (a) Carcasses of swine which give off a pronounced sexual odor shall be condemned. (b) The meat of swine carcasses which give off a sexual odor less than pronounced may be passed for...

Odor and odorous chemical emissions from animal buildings: Part 5 - Correlations between odor intensities and chemical concentrations (GC-MS/O)

USDA-ARS?s Scientific Manuscript database

Simultaneous chemical and sensory analysis based on gas chromatography-mass spectrometry-olfactometry (GC-MS-O) of air samples from livestock operations is a very useful approach for quantification of target odorous gases and also for ranking of odorous compounds. This information can help link spec...

Drosophila Learn Opposing Components of a Compound Food Stimulus

PubMed Central

Das, Gaurav; Klappenbach, Martín; Vrontou, Eleftheria; Perisse, Emmanuel; Clark, Christopher M.; Burke, Christopher J.; Waddell, Scott

2014-01-01

Summary Dopaminergic neurons provide value signals in mammals and insects [1–3]. During Drosophila olfactory learning, distinct subsets of dopaminergic neurons appear to assign either positive or negative value to odor representations in mushroom body neurons [4–9]. However, it is not known how flies evaluate substances that have mixed valence. Here we show that flies form short-lived aversive olfactory memories when trained with odors and sugars that are contaminated with the common insect repellent DEET. This DEET-aversive learning required the MB-MP1 dopaminergic neurons that are also required for shock learning [7]. Moreover, differential conditioning with DEET versus shock suggests that formation of these distinct aversive olfactory memories relies on a common negatively reinforcing dopaminergic mechanism. Surprisingly, as time passed after training, the behavior of DEET-sugar-trained flies reversed from conditioned odor avoidance into odor approach. In addition, flies that were compromised for reward learning exhibited a more robust and longer-lived aversive-DEET memory. These data demonstrate that flies independently process the DEET and sugar components to form parallel aversive and appetitive olfactory memories, with distinct kinetics, that compete to guide learned behavior. PMID:25042590

Does Human Body Odor Represent a Significant and Rewarding Social Signal to Individuals High in Social Openness?

PubMed Central

Lübke, Katrin T.; Croy, Ilona; Hoenen, Matthias; Gerber, Johannes; Pause, Bettina M.; Hummel, Thomas

2014-01-01

Across a wide variety of domains, experts differ from novices in their response to stimuli linked to their respective field of expertise. It is currently unknown whether similar patterns can be observed with regard to social expertise. The current study therefore focuses on social openness, a central social skill necessary to initiate social contact. Human body odors were used as social cues, as they inherently signal the presence of another human being. Using functional MRI, hemodynamic brain responses to body odors of women reporting a high (n = 14) or a low (n = 12) level of social openness were compared. Greater activation within the inferior frontal gyrus and the caudate nucleus was observed in high socially open individuals compared to individuals low in social openness. With the inferior frontal gyrus being a crucial part of the human mirror neuron system, and the caudate nucleus being implicated in social reward, it is discussed whether human body odor might constitute more of a significant and rewarding social signal to individuals high in social openness compared to individuals low in social openness process. PMID:24718308

Parallel odor processing by mitral and middle tufted cells in the olfactory bulb.

PubMed

Cavarretta, Francesco; Burton, Shawn D; Igarashi, Kei M; Shepherd, Gordon M; Hines, Michael L; Migliore, Michele

2018-05-16

The olfactory bulb (OB) transforms sensory input into spatially and temporally organized patterns of activity in principal mitral (MC) and middle tufted (mTC) cells. Thus far, the mechanisms underlying odor representations in the OB have been mainly investigated in MCs. However, experimental findings suggest that MC and mTC may encode parallel and complementary odor representations. We have analyzed the functional roles of these pathways by using a morphologically and physiologically realistic three-dimensional model to explore the MC and mTC microcircuits in the glomerular layer and deeper plexiform layer. The model makes several predictions. MCs and mTCs are controlled by similar computations in the glomerular layer but are differentially modulated in deeper layers. The intrinsic properties of mTCs promote their synchronization through a common granule cell input. Finally, the MC and mTC pathways can be coordinated through the deep short-axon cells in providing input to the olfactory cortex. The results suggest how these mechanisms can dynamically select the functional network connectivity to create the overall output of the OB and promote the dynamic synchronization of glomerular units for any given odor stimulus.

Olfactory-visual congruence effects stable across ages: yellow is warmer when it is pleasantly lemony.

PubMed

Guerdoux, Estelle; Trouillet, Raphaël; Brouillet, Denis

2014-07-01

This study aimed to examine the age-related differences in the olfactory-visual cross-correspondences and the extent to which they are moderated by the odors pleasantness. Sixty participants aged from 20- to 75- years (young, middle-aged and older adults) performed a priming task to explore the influence of six olfactory primes (lemon, orange, rose, thyme, mint and fish) on the categorization (cool vs. warm) of six subsequent color targets (yellow, orange, pink, malachite green, grass-green, and blue-gray). We tested mixed effects models. Response times were regressed on covariates models using both fixed effects (Groups of age, olfactory Pleasantness and multimodal Condition) and cross-random effects (Subject, Color and Odor). The random effects coding for Odor (p < .001) and Color (p = .001) were significant. There was a significant interaction effect ( p= .004) between Condition × Pleasantness, but not with Groups of age. The compatibility effect (i.e., when odors and colors were congruent, the targets processing were facilitated) was as much enhanced as the olfactory primes were pleasant. Cross-correspondences between olfaction and vision may be robust in aging. They should be considered alongside spatiotemporal but also emotional congruency.

Advanced Exploration Systems (AES) Logistics Reduction Project: Crew Clothing Care Process Development. Revision: Basic

NASA Technical Reports Server (NTRS)

Demmler, Morgan; Whitehead, Nickolas; Poritz, Darwin; Orndoff, Evelyne

2017-01-01

This report covers the use of ozone and mist with detergent to develop zero-gravity laundering technology. Different concentrations of detergent with and without ozone were applied to remove odor from t-shirts used during exercise. The fabrics of these shirts were categorized into two groups: hydrophobic (polyester and modacrylic) and hydrophilic (cotton and Merino wool). It was found that applying detergent solution as a mist sufficient to achieve saturation can be effective in eliminating odors from athletically soiled shirts either with or without exposure to ozone.

Different thresholds for detection and discrimination of odors in the honey bee (Apis mellifera).

PubMed

Wright, Geraldine A; Smith, Brian H

2004-02-01

Naturally occurring odors used by animals for mate recognition, food identification and other purposes must be detected at concentrations that vary across several orders of magnitude. Olfactory systems must therefore have the capacity to represent odors over a large range of concentrations regardless of dramatic changes in the salience, or perceived intensity, of a stimulus. The stability of the representation of an odor relative to other odors across concentration has not been extensively evaluated. We tested the ability of honey bees to discriminate pure odorants across a range of concentrations at and above their detection threshold. Our study showed that pure odorant compounds became progressively easier for honey bees to discriminate with increasing concentration. Discrimination is, therefore, a function of odorant concentration. We hypothesize that the recruitment of sensory cell populations across a range of concentrations may be important for odor coding, perhaps by changing its perceptual qualities or by increasing its salience against background stimuli, and that this mechanism is a general property of olfactory systems.

Sparse, decorrelated odor coding in the mushroom body enhances learned odor discrimination.

PubMed

Lin, Andrew C; Bygrave, Alexei M; de Calignon, Alix; Lee, Tzumin; Miesenböck, Gero

2014-04-01

Sparse coding may be a general strategy of neural systems for augmenting memory capacity. In Drosophila melanogaster, sparse odor coding by the Kenyon cells of the mushroom body is thought to generate a large number of precisely addressable locations for the storage of odor-specific memories. However, it remains untested how sparse coding relates to behavioral performance. Here we demonstrate that sparseness is controlled by a negative feedback circuit between Kenyon cells and the GABAergic anterior paired lateral (APL) neuron. Systematic activation and blockade of each leg of this feedback circuit showed that Kenyon cells activated APL and APL inhibited Kenyon cells. Disrupting the Kenyon cell-APL feedback loop decreased the sparseness of Kenyon cell odor responses, increased inter-odor correlations and prevented flies from learning to discriminate similar, but not dissimilar, odors. These results suggest that feedback inhibition suppresses Kenyon cell activity to maintain sparse, decorrelated odor coding and thus the odor specificity of memories.

Do trained dogs discriminate individual body odors of women better than those of men?

PubMed

Jezierski, Tadeusz; Sobczyńska, Magdalena; Walczak, Marta; Gorecka-Bruzda, Aleksandra; Ensminger, John

2012-05-01

Scent identification lineups using dogs are a potentially valuable forensic tool, but have been dismissed by some critics because of cases where a false identification was shown to have occurred. It is not known, however, why dogs appear to make more false indications to the odors of some persons than of others. In this study, human genders were compared as to the degree their individual odors are distinguishable or "attractive" to dogs. Six dogs were trained to smell an individual's hand odor sample and then find the matching hand odor sample in a lineup of five odors. Using one-gender lineups and two-gender lineups with different gender ratios, it was found that dogs trained for the study identified individual women's hand odors more accurately than those of men. It is hypothesized that this is either because of differences in chemical compounds making discrimination of women's odors easier, or because of greater "odor attractiveness" of women's scents to dogs. © 2012 American Academy of Forensic Sciences.

Odor-identity dependent motor programs underlie behavioral responses to odors

PubMed Central

Jung, Seung-Hye; Hueston, Catherine; Bhandawat, Vikas

2015-01-01

All animals use olfactory information to perform tasks essential to their survival. Odors typically activate multiple olfactory receptor neuron (ORN) classes and are therefore represented by the patterns of active ORNs. How the patterns of active ORN classes are decoded to drive behavior is under intense investigation. In this study, using Drosophila as a model system, we investigate the logic by which odors modulate locomotion. We designed a novel behavioral arena in which we could examine a fly’s locomotion under precisely controlled stimulus condition. In this arena, in response to similarly attractive odors, flies modulate their locomotion differently implying that odors have a more diverse effect on locomotion than was anticipated. Three features underlie odor-guided locomotion: First, in response to odors, flies modulate a surprisingly large number of motor parameters. Second, similarly attractive odors elicit changes in different motor programs. Third, different ORN classes modulate different subset of motor parameters. DOI: http://dx.doi.org/10.7554/eLife.11092.001 PMID:26439011

Introducing Computational Fluid Dynamics Simulation into Olfactory Display

NASA Astrophysics Data System (ADS)

Ishida, Hiroshi; Yoshida, Hitoshi; Nakamoto, Takamichi

An olfactory display is a device that delivers various odors to the user's nose. It can be used to add special effects to movies and games by releasing odors relevant to the scenes shown on the screen. In order to provide high-presence olfactory stimuli to the users, the display must be able to generate realistic odors with appropriate concentrations in a timely manner together with visual and audio playbacks. In this paper, we propose to use computational fluid dynamics (CFD) simulations in conjunction with the olfactory display. Odor molecules released from their source are transported mainly by turbulent flow, and their behavior can be extremely complicated even in a simple indoor environment. In the proposed system, a CFD solver is employed to calculate the airflow field and the odor dispersal in the given environment. An odor blender is used to generate the odor with the concentration determined based on the calculated odor distribution. Experimental results on presenting odor stimuli synchronously with movie clips show the effectiveness of the proposed system.

Trimethylamine: the substance mainly responsible for the fishy odor often associated with bacterial vaginosis.

PubMed

Brand, J M; Galask, R P

1986-11-01

The vaginal discharge of women with bacterial vaginosis often has a prominent fishy odor. Intensification of this fishy odor by the addition of strong base to the vaginal discharge suggests that it could be due to trimethylamine, the substance responsible for the characteristic odor of spoiling fish. Samples were collected from 11 women with a vaginal discharge having a fishy odor and from 10 women with no detectable odor. Gas chromatographic analysis of headspace samples of alkalinized vaginal discharges indicated the presence of trimethylamine in all 11 samples with the fishy odor but not in the other samples. The chemical identity of trimethylamine was confirmed by gas chromatography-mass spectrometry of headspace samples from two vaginal discharge samples. It is concluded that trimethylamine is the primary cause of the fishy odor associated with bacterial vaginosis.

Immunization alters body odor.

PubMed

Kimball, Bruce A; Opiekun, Maryanne; Yamazaki, Kunio; Beauchamp, Gary K

2014-04-10

Infections have been shown to alter body odor. Because immune activation accompanies both infection and immunization, we tested the hypothesis that classical immunization might similarly result in the alteration of body odors detectable by trained biosensor mice. Using a Y-maze, we trained biosensor mice to distinguish between urine odors from rabies-vaccinated (RV) and unvaccinated control mice. RV-trained mice generalized this training to mice immunized with the equine West Nile virus (WNV) vaccine compared with urine of corresponding controls. These results suggest that there are similarities between body odors of mice immunized with these two vaccines. This conclusion was reinforced when mice could not be trained to directly discriminate between urine odors of RV- versus WNV-treated mice. Next, we trained biosensor mice to discriminate the urine odors of mice treated with lipopolysaccharide (LPS; a general elicitor of innate immunological responses) from the urine of control mice. These LPS-trained biosensors could distinguish between the odors of LPS-treated mouse urine and RV-treated mouse urine. Finally, biosensor mice trained to distinguish between the odors of RV-treated mouse urine and control mouse urine did not generalize this training to discriminate between the odors of LPS-treated mouse urine and control mouse urine. From these experiments, we conclude that: (1) immunization alters urine odor in similar ways for RV and WNV immunizations; and (2) immune activation with LPS also alters urine odor but in ways different from those of RV and WNV. Published by Elsevier Inc.

Semantic networks for odors and colors in Alzheimer's disease.

PubMed

Razani, Jill; Chan, Agnes; Nordin, Steven; Murphy, Claire

2010-05-01

Impairment in odor-naming ability and in verbal and visual semantic networks raised the hypothesis of a breakdown in the semantic network for odors in Alzheimer's disease (AD). The current study addressed this hypothesis. Twenty-four individuals, half patients with probable AD and half control participants, performed triadic-similarity judgments for odors and colors, separately, which, utilizing the multidimensional scaling (MDS) technique of individual difference scaling analysis (INDSCAL), generated two-dimensional configurations of similarity. The abilities to match odors and colors with written name labels were assessed to investigate disease-related differences in ability to identify and conceptualize the stimuli. In addition, responses on attribute-sorting tasks, requiring the odor and color perceptions to be categorized as one polarity of a certain dimension, were obtained to allow for objective interpretation of the MDS spatial maps. Whereas comparison subjects generated spatial maps based predominantly on relatively abstract characteristics, patients with AD classified odors on perceptual characteristics. The maps for patients with AD also showed disorganized groupings and loose associations between odors. Their normal configurations for colors imply that the patients were able to comprehend the task per se. The data for label matching and for attribute sorting provide further evidence for a disturbance in semantic odor memory in AD. The patients performed poorer than controls on both these odor tasks, implying that the ability to identify and/or conceptualize odors is impaired in AD. The results provide clear evidence for deterioration of the structure of semantic knowledge for odors in AD.

Sensory evaluation of the synergism among odorants present in concentrations below their odor threshold in a Chinese jasmine green tea infusion.

PubMed

Ito, Yuriko; Kubota, Kikue

2005-01-01

The mechanism for the contribution of subthreshold aroma constituents to the overall jasmine tea odor impression was studied on the basis of a sensory evaluation. Binary model aqueous solutions containing the authentic odorants of a jasmine tea infusion, (E)-2-hexenyl hexanoate (I), (Z)-3-hexenol (II), and indole (III), were each prepared in a concentration below the odor threshold. Each solution had no aroma, but when 4-hexanolide replaced only 5% of each odorant, the odor intensity of each model solution was significantly strengthened. An astringent note and heavy note were recognized for each solution as the commonly perceived characteristics from the sensory evaluation. The concentration of 4-hexanolide added was also at the subthreshold level. The results suggest mutual interaction between odorants I, II, or III and 4-hexanolide. The effect on the overall odor sensation of a jasmine tea infusion by adding 4-hexanolide at a concentration below its odor threshold was also studied. In this case, the intensity of both the sweet and astringent notes was significantly strengthened in comparison with the odor impression of the original jasmine tea infusion. This phenomenon is considered to have been a synergistic effect between subthreshold odor compounds in the jasmine tea infusion. The results of this study clarify for the first time that the subthreshold aroma constituents play an important role in the characteristic flavor of a jasmine tea infusion.

Odor modeling methodology for determining the odor buffer distance for sanitary landfills

DOE Office of Scientific and Technical Information (OSTI.GOV)

Song, Dukman.

1991-01-01

The objective of this study is to create a methodology whereby reductions in off-site odor migrations resulting from operational and design changes in new or expanded sanitary landfills can be evaluated. The Ann Arbor Sanitary Landfill was chosen as a prototype landfill to test a hypothesis for this study. This study is a unique approach to odor prediction at sanitary landfills using surface flux measurements, odor threshold panel measurements, and dispersion modeling. Flux measurements were made at open tipping face, temporary cover, final cover, vents, and composting zones of the Ann Arbor Sanitary Landfill. Surface gas velocities and in-ground concentrationsmore » were determined to allow a quantification of the total and methane gas flow rate. Odor threshold panel measurements were performed to determine the odor intensity in odor units at the corresponding sites. The used the flux and odor panel measurements in the Industrial Source Complex Terrain Model to determine the hourly averaged highest and second highest odor levels at 175 receptors placed at the property boundary and 25 nearby residential locations. Using measured values for velocity, subsurface CH{sub 4} concentration and odor intensity, it was determined that the proposed 1990 operations with a buffer distance of 600 feet provided at least a factor of five protection below 1 o.u. of the odor threshold for all receptors, and dilution protection equal to the historic 1984 operations with a 1,200 feet isolation distance.« less

Retronasal odor representations in the dorsal olfactory bulb of rats

PubMed Central

Gautam, Shree Hari; Verhagen, Justus V.

2012-01-01

Animals perceive their olfactory environment not only from odors originating in the external world (orthonasal route) but also from odors released in the oral cavity while eating food (retronasal route). Retronasal olfaction is crucial for the perception of food flavor in humans. However, little is known about the retronasal stimulus coding in the brain. The most basic question is if and how route affects the odor representations at the level of the olfactory bulb (OB), where odor quality codes originate. We used optical calcium imaging of presynaptic dorsal OB responses to odorants in anesthetized rats to ask whether the rat OB could be activated retronasally, and how these responses compare to orthonasal responses under similar conditions. We further investigated the effects of specific odorant properties on orthoversus retronasal response patterns. We found that at a physiologically relevant flow rate retronasal odorants can effectively reach the olfactory receptor neurons, eliciting glomerular response patterns that grossly overlap with those of orthonasal responses, but differ from the orthonasal patterns in the response amplitude and temporal dynamics. Interestingly, such differences correlated well with specific odorant properties. Less volatile odorants yielded relatively smaller responses retronasally, but volatility did not affect relative temporal profiles. More polar odorants responded with relatively longer onset latency and time to peak retronasally, but polarity did not affect relative response magnitudes. These data provide insight into the early stages of retronasal stimulus coding and establish relationships between ortho- and retronasal odor representations in the rat OB. PMID:22674270

Quantitative method to determine the regional drinking water odorant regulation goals based on odor sensitivity distribution: illustrated using 2-MIB.

PubMed

Yu, Jianwei; An, Wei; Cao, Nan; Yang, Min; Gu, Junong; Zhang, Dong; Lu, Ning

2014-07-01

Taste and odor (T/O) in drinking water often cause consumer complaints and are thus regulated in many countries. However, people in different regions may exhibit different sensitivities toward T/O. This study proposed a method to determine the regional drinking water odorant regulation goals (ORGs) based on the odor sensitivity distribution of the local population. The distribution of odor sensitivity to 2-methylisoborneol (2-MIB) by the local population in Beijing, China was revealed by using a normal distribution function/model to describe the odor complaint response to a 2-MIB episode in 2005, and a 2-MIB concentration of 12.9 ng/L and FPA (flavor profile analysis) intensity of 2.5 was found to be the critical point to cause odor complaints. Thus the Beijing ORG for 2-MIB was determined to be 12.9 ng/L. Based on the assumption that the local FPA panel can represent the local population in terms of sensitivity to odor, and that the critical FPA intensity causing odor complaints was 2.5, this study tried to determine the ORGs for seven other cities of China by performing FPA tests using an FPA panel from the corresponding city. ORG values between 12.9 and 31.6 ng/L were determined, showing that a unified ORG may not be suitable for drinking water odor regulations. This study presents a novel approach for setting drinking water odor regulations. Copyright © 2014. Published by Elsevier B.V.

Neuronal pattern separation in the olfactory bulb improves odor discrimination learning

PubMed Central

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

2015-01-01

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

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

PubMed

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

2015-10-01

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

Right Orbitofrontal Cortex Mediates Conscious Olfactory Perception

PubMed Central

Li, Wen; Lopez, Leonardo; Osher, Jason; Howard, James D.; Parrish, Todd B.; Gottfried, Jay A.

2013-01-01

Understanding how the human brain translates sensory impressions into conscious percepts is a key challenge of neuroscience research. Work in this area has overwhelmingly centered on the conscious experience of vision at the exclusion of the other senses—in particular, smell. We hypothesized that the orbitofrontal cortex (OFC) is a central substrate for olfactory conscious experience because of its privileged physiological role in odor processing. Combining functional magnetic resonance imaging, peripheral autonomic recordings, and olfactory psychophysics, we studied a case of complete anosmia (smell loss) in a patient with circumscribed traumatic brain injury to the right OFC. Despite a complete absence of conscious olfaction, the patient exhibited robust “blind smell,” as indexed by reliable odor-evoked neural activity in the left OFC and normal autonomic responses to odor hedonics during presentation of stimuli to the left nostril. These data highlight the right OFC’s critical role in subserving human olfactory consciousness. PMID:20817780

Epac Activation Initiates Associative Odor Preference Memories in the Rat Pup

ERIC Educational Resources Information Center

Grimes, Matthew T.; Powell, Maria; Gutierrez, Sandra Mohammed; Darby-King, Andrea; Harley, Carolyn W.; McLean, John H.

2015-01-01

Here we examine the role of the exchange protein directly activated by cAMP (Epac) in ß-adrenergic-dependent associative odor preference learning in rat pups. Bulbar Epac agonist (8-pCPT-2-O-Me-cAMP, or 8-pCPT) infusions, paired with odor, initiated preference learning, which was selective for the paired odor. Interestingly, pairing odor with Epac…

[Specific odor component produced by Mycobacterium lepraemurium on Ogawa yolk medium].

PubMed

Mori, T; Aishima, T

1992-11-01

When Mycobacterium lepraemurium is grown on the 1% Ogawa yolk medium, it produces a specific odor. This odor was not observed in other easily cultivable acid-fast bacilli. Therefore, identification of the components responsible for the specific odor produced by M. lepraemurium was attempted. The odor components were extracted for overnight with sterilized and distilled water from the Ogawa yolk medium on which M. lepraemurium had been cultivated for two months. The odor components in the extract was adsorbed on refined charcoal. After washing with distilled water for three times, the charcoal was dried. Then the odor components were eluted from the charcoal with ethanol and the eluate was condensed under nitrogen gas flow at 40 degrees C. The condensate was analyzed by Gas-Chromatography-Mass-Spectrum (GC-MS). Phenylethanol and phenylacetic acid were identified as major odor components. A mixture of authentic phenylacetic acid, its methyl and ethyl esters, smelled similar to the odor of cultivated medium of M. lepraemurium. Thus, phenylacetic acid was identified as the key odor component produced by M. lepraemurium. When initial isolation culture of M. lepraemurium from murine leproma was cultivated on the Ogawa yolk medium by adding phenylacetic acid, growth inhibition was brought by the compound.

A Sensory 3D Map of the Odor Description Space Derived from a Comparison of Numeric Odor Profile Databases.

PubMed

Zarzo, Manuel

2015-06-01

Many authors have proposed different schemes of odor classification, which are useful to aid the complex task of describing smells. However, reaching a consensus on a particular classification seems difficult because our psychophysical space of odor description is a continuum and is not clustered into well-defined categories. An alternative approach is to describe the perceptual space of odors as a low-dimensional coordinate system. This idea was first proposed by Crocker and Henderson in 1927, who suggested using numeric profiles based on 4 dimensions: "fragrant," "acid," "burnt," and "caprylic." In the present work, the odor profiles of 144 aroma chemicals were compared by means of statistical regression with comparable numeric odor profiles obtained from 2 databases, enabling a plausible interpretation of the 4 dimensions. Based on the results and taking into account comparable 2D sensory maps of odor descriptors from the literature, a 3D sensory map (odor cube) has been drawn up to improve understanding of the similarities and dissimilarities of the odor descriptors most frequently used in fragrance chemistry. © The Author 2015. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Effects of Breast Milk and Vanilla Odors on Premature Neonate's Heart Rate and Blood Oxygen Saturation During and After Venipuncture.

PubMed

Neshat, Hanieh; Jebreili, Mahnaz; Seyyedrasouli, Aleheh; Ghojazade, Morteza; Hosseini, Mohammad Bagher; Hamishehkar, Hamed

2016-06-01

Different studies have shown that the use of olfactory stimuli during painful medical procedures reduces infants' response to pain. The main purpose of the current study was to investigate the effect of breast milk odor and vanilla odor on premature infants' vital signs including heart rate and blood oxygen saturation during and after venipuncture. A total of 135 preterm infants were randomly selected and divided into three groups of control, vanilla odor, and breast milk odor. Infants in the breast milk group and the vanilla group were exposed to breast milk odor and vanilla odor from 5 minutes prior to sampling until 30 seconds after sampling. The results showed that breast milk odor has a significant effect on the changes of neonatal heart rate and blood oxygen saturation during and after venipuncture and decreased the variability of premature infants' heart rate and blood oxygen saturation. Vanilla odor has no significant effect on premature infants' heart rate and blood oxygen saturation. Breast milk odor can decrease the variability of premature infants' heart rate and blood oxygen saturation during and after venipuncture. Copyright © 2015. Published by Elsevier B.V.

Direct nuclear magnetic resonance observation of odorant binding to mouse odorant receptor MOR244-3.

PubMed

Burger, Jessica L; Jeerage, Kavita M; Bruno, Thomas J

2016-06-01

Mammals are able to perceive and differentiate a great number of structurally diverse odorants through the odorant's interaction with odorant receptors (ORs), proteins found within the cell membrane of olfactory sensory neurons. The natural gas industry has used human olfactory sensitivity to sulfur compounds (thiols, sulfides, etc.) to increase the safety of fuel gas transport, storage, and use through the odorization of this product. In the United States, mixtures of sulfur compounds are used, but the major constituent of odorant packages is 2-methylpropane-2-thiol, also known as tert-butyl mercaptan. It has been fundamentally challenging to understand olfaction and odorization due to the low affinity of odorous ligands to the ORs and the difficulty in expressing a sufficient number of OR proteins. Here, we directly observed the binding of tert-butyl mercaptan and another odiferous compound, cis-cyclooctene, to mouse OR MOR244-3 on living cells by saturation transfer difference (STD) nuclear magnetic resonance (NMR) spectroscopy. This effort lays the groundwork for resolving molecular mechanisms responsible for ligand binding and resulting signaling, which in turn will lead to a clearer understanding of odorant recognition and competition. Published by Elsevier Inc.

Molecular receptive range variation among mouse odorant receptors for aliphatic carboxylic acids

PubMed Central

Repicky, Sarah E.; Luetje, Charles W.

2009-01-01

The ability of mammals to identify and distinguish among many thousands of different odorants suggests a combinatorial use of odorant receptors, with each receptor detecting multiple odorants and each odorant interacting with multiple receptors. Numerous receptors may be devoted to the sampling of particularly important regions of odor space. Here we explore the similarities and differences in the molecular receptive ranges of four mouse odorant receptors (MOR23-1, MOR31-4, MOR32-11 and MOR40-4), which have previously been identified as receptors for aliphatic carboxylic acids. Each receptor was expressed in Xenopus oocytes, along with Gαolf and the cystic fibrosis transmembrane regulator to allow electrophysiological assay of receptor responses. We find that even though these receptors are relatively unrelated, there is extensive overlap among their receptive ranges. That is, these receptors sample a similar region of odor space. However, the receptive range of each receptor is unique. Thus, these receptors contribute to the depth of coverage of this small region of odor space. Such a group of receptors with overlapping, but distinct receptive ranges, may participate in making fine distinctions among complex mixtures of closely related odorant compounds. PMID:19166503

The bed nucleus of the stria terminalis is critical for sexual solicitation, but not for opposite-sex odor preference, in female Syrian hamsters.

PubMed

Martinez, Luis A; Petrulis, Aras

2011-11-01

Successful reproduction in vertebrates depends critically upon a suite of precopulatory behaviors that occur prior to mating. In Syrian hamsters (Mesocricetus auratus), these behaviors include vaginal scent marking and preferential investigation of male odors. The neural regulation of vaginal marking and opposite-sex odor preference likely involves an interconnected set of steroid-sensitive nuclei that includes the medial amygdala (MA), the bed nucleus of the stria terminalis (BNST), and the medial preoptic area (MPOA). For example, lesions of MA eliminate opposite-sex odor preference and reduce overall levels of vaginal marking, whereas lesions of MPOA decrease vaginal marking in response to male odors. Although BNST is densely interconnected with both MA and MPOA, little is known about the role of BNST in female precopulatory behaviors. To address this question, females received either bilateral, excitotoxic lesions of BNST (BNST-X) or sham lesions (SHAM), and were tested for scent marking and for investigatory responses to male and female odors. Whereas SHAM females vaginal marked more to male odors than female odors on two days of the estrous cycle, BNST-X females marked at equivalent levels to both odors. This deficit is not due to alterations in social odor investigation, as both BNST-X and SHAM females investigated male odors more than female odors. Finally, BNST lesions did not generally disrupt the cyclic changes in reproductive behaviors that occur across the estrous cycle. Taken together, these results demonstrate that BNST is critical for the normal expression of solicitational behaviors by females in response to male odor stimuli. Copyright © 2011 Elsevier Inc. All rights reserved.

The bed nucleus of the stria terminalis is critical for sexual solicitation, but not for opposite-sex odor preference, in female Syrian hamsters

PubMed Central

Martinez, Luis A.; Petrulis, Aras

2011-01-01

Successful reproduction in vertebrates depends critically upon a suite of precopulatory behaviors that occur prior to mating. In Syrian hamsters (Mesocricetus auratus), these behaviors include vaginal scent marking and preferential investigation of male odors. The neural regulation of vaginal marking and opposite-sex odor preference likely involves an interconnected set of steroid-sensitive nuclei that includes the medial amygdala (MA), the bed nucleus of the stria terminalis (BNST), and the medial preoptic area (MPOA). For example, lesions of MA eliminate opposite-sex odor preference and reduce overall levels of vaginal marking, whereas lesions of MPOA decrease vaginal marking in response to male odors. Although BNST is densely interconnected with both MA and MPOA, little is known about the role of BNST in female precopulatory behaviors. To address this question, females received either bilateral, excitotoxic lesions of BNST (BNST-X) or sham lesions (SHAM), and were tested for scent marking and for investigatory responses to male and female odors. Whereas SHAM females vaginal marked more to male odors than female odors on two days of the estrous cycle, BNST-X females marked at equivalent levels to both odors. This deficit is not due to alterations in social odor investigation, as both BNST-X and SHAM females investigated male odors more than female odors. Finally, BNST lesions did not generally disrupt the cyclic changes in reproductive behaviors that occur across the estrous cycle. Taken together, these results demonstrate that BNST is critical for the normal expression of solicitational behaviors by females in response to male odor stimuli. PMID:21925504

THE SEARCH DYNAMICS OF RECRUITED HONEY BEES, APIS MELLIFERA LIGUSTICA SPINOLA.

PubMed

Friesen, Larry Jon

1973-02-01

Some variables in the recruitment process of honey bees were studied as they affected the distribution and success of the searching population in the field. The dance language and odor dependence hypotheses were contrasted and their predictions compared with the following observations. 1. Recruits were attracted to the odors from the food which were carried by foragers and were dependent on these odors for success. 2. A monitoring of recruit densities in the field demonstrated an association of searchers with the forager flight path. 3. The degree of correspondence between the distribution of recruits and the direction of the flight path to the feeding site was correlated with wind direction, not search efficiency. 4. Feeding stations upwind of the hive provided the highest recruit success rates, shortest search times, and the least dependence on wind speed. Downwind stations provided the lowest recruit success rates, the longest search times, and the greatest dependence on wind speed. 5. A disproportionate increase in recruit success with an increase in the number of foragers visiting a feeding site was correlated with the density of the foragers in the field. 6. Increased bee densities at the feeding site, even with bees from different hives, increased recruit success and shortened search times. 7. The progression of and the extremely long intervals between the onset of recruit arrivals at areas along the forager flight path suggested communication among bees in the field and a dependence of recruit success on the density and growth of the searching population. These observations are compatible with an odor dependent search behavior and together fail to support the predictions of the dance language hypothesis. Dance attendants appeared to have been conditioned to the odors associated with returning foragers and, after leaving the hive, entered a searching population dependent on these odors for success. The dependence of recruit success on food odor at the feeding station, the density of foragers between this station and the hive, and the direction of the wind indicates that the integrity of the forager flight path was extremely important to this success. The distributions and extended search times of recruits indicated a search behavior based on positive anemotaxis during the perception of the proper combination of odors and negative anemotaxis after the loss of this stimulation.

Characterization and control of odorous gases at a landfill site: a case study in Hangzhou, China.

PubMed

Ying, Ding; Chuanyu, Cai; Bin, Hu; Yueen, Xu; Xuejuan, Zheng; Yingxu, Chen; Weixiang, Wu

2012-02-01

Municipal solid waste (MSW) landfills are one of the major sources of offensive odors potentially creating annoyance in adjacent communities. At the end of May 2007, an odor pollution incident occurred at the Tianziling landfill site, Hangzhou, China, where the residents lodged complaints about the intense odor from the landfill, which drew a significant attention from the government. In this study, ambient air monitoring was conducted at the Tianziling landfill site. The main odor composition of the gas samples collected on June 1st 2007 and the reduction of various odorous gases from the samples collected on June 1st 2009 due to the applied odor control techniques were determined using gas chromatography-mass spectrometry (GC-MS). In addition, variations of primary odorous gaseous (NH(3) and H(2)S) concentrations at different locations in the landfill site from July 2007 to June 2009 were also investigated by using classical spectrophotometric methods. Results showed that a total of 68 volatile compounds were identified among which H(2)S (56.58-579.84 μg/m(3)) and NH(3) (520-4460 μg/m(3)) were the notable odor components contributing to 4.47-10.92% and 83.91-93.94% of total concentrations, respectively. Similar spatial and temporal shifts of H(2)S and NH(3) concentrations were observed and were significantly affected by environmental factors including temperature, air pressure and wind direction. Odor pollution was worse when high temperature, high humidity, low air pressure, and southeast, northeast or east wind appeared. Moreover, the environmental sampling points of the dumping area and the leachate treatment plant were found to be the main odor sources at the Tianziling landfill site. The odor control technologies used in this project had a good mitigating effect on the primary odorous compounds. This study provides long-term valuable information concerning the characteristics and control of odors at landfill sites in a long run. Copyright © 2011 Elsevier Ltd. All rights reserved.

Effects of historically familiar and novel predator odors on the physiology of an introduced prey

PubMed Central

Mella, Valentina S. A.; Cooper, Christine E.; Davies, Stephen J. J. F.

2016-01-01

Abstract Predator odors can elicit fear responses in prey and predator odor recognition is generally associated with physiological responses. Prey species are often more likely to respond to the odor of familiar rather than alien predators. However, predator naïvety in an introduced prey species has rarely been investigated. We examined the physiological response, as shown by changes in ventilatory variables, of an introduced terrestrial herbivore, the European rabbit Oryctolagus cuniculus, in Australia, to the odor of potential predators and to control odors (distilled water and horse), to explore if responses were limited to historical (cat and fox) predators, or extended to historically novel predators (snake and quoll). All odors except distilled water elicited a response, with rabbits showing long-term higher respiratory frequencies and lower tidal volumes after introduction of the odors, indicating an increase in alertness. However, the intensity of the rabbits’ reaction could not be directly linked to any pattern of response with respect to the history of predator–prey relationships. Rabbits exhibited significantly stronger reactions in response to both cat and quoll odors than they did to distilled water, but responses to horse, fox, and snake odor were similar to that of water. Our results show that the introduced rabbit can respond to both historical and novel predators in Australia, and suggest that shared evolutionary history is not necessarily a prerequisite to predator odor recognition. PMID:29491891

Effects of historically familiar and novel predator odors on the physiology of an introduced prey.

PubMed

Mella, Valentina S A; Cooper, Christine E; Davies, Stephen J J F

2016-02-01

Predator odors can elicit fear responses in prey and predator odor recognition is generally associated with physiological responses. Prey species are often more likely to respond to the odor of familiar rather than alien predators. However, predator naïvety in an introduced prey species has rarely been investigated. We examined the physiological response, as shown by changes in ventilatory variables, of an introduced terrestrial herbivore, the European rabbit Oryctolagus cuniculus , in Australia, to the odor of potential predators and to control odors (distilled water and horse), to explore if responses were limited to historical (cat and fox) predators, or extended to historically novel predators (snake and quoll). All odors except distilled water elicited a response, with rabbits showing long-term higher respiratory frequencies and lower tidal volumes after introduction of the odors, indicating an increase in alertness. However, the intensity of the rabbits' reaction could not be directly linked to any pattern of response with respect to the history of predator-prey relationships. Rabbits exhibited significantly stronger reactions in response to both cat and quoll odors than they did to distilled water, but responses to horse, fox, and snake odor were similar to that of water. Our results show that the introduced rabbit can respond to both historical and novel predators in Australia, and suggest that shared evolutionary history is not necessarily a prerequisite to predator odor recognition.

Recognition of Bread Key Odorants by Using Polymer Coated QCMs

NASA Astrophysics Data System (ADS)

Nakai, Takashi; Kouno, Shinji; Hiruma, Naoya; Shuzo, Masaki; Delaunay, Jean-Jacques; Yamada, Ichiro

Polyisobutylene (PIB) polymer and methylphenylsiloxane (25%) diphenylsiloxane (75%) copolymer (OV25) were coated on Quartz Crystal Microbalance (QCM) sensors and used in recognition of bread key odorants. Representative compounds of key roasty odorants of bread were taken as 3-acetylpyridine and benzaldehyde, and representative key fatty odorants were hexanal and (E)-2-nonenal. Both OV25- and PIB-coated QCM fabricated sensors could detect concentration as low as 0.9 ppm of 3-acetylpyridine and 1.2 ppm of (E)-2-nonenal. The sensitivity to 3-acetylpyridine of the OV25-coated QCM was about 1000 times higher than that of ethanol, the major interference compound in bread key odorant analysis. Further, the OV25-coated QCM response was 5-6 times and 2-3 times larger than that of the PIB-coated QCM when exposed to roasty odorants and to fatty odorants, respectively. The difference in sensitivity of the OV25- and PIB-coated QCMs we fabricated made possible to discriminate roasty from fatty odorants as was evidenced by the odor recognition map representing the frequency shifts of the OV25-coated QCM against the frequency shift of the PIB-coated QCM. In conclusion, we found that the combination of an OV25-coated QCM and a PIB-coated QCM was successful in discriminating roasty odorants from fatty odorants at the ppm level.

Case study of odor and indoor air quality assessment in the dewatering building at the Stickney Water Reclamation Plant.

PubMed

Sharma, Manju; O'Connell, Susan; Garelli, Brett; Sattayatewa, Chakkrid; Moschandreas, Demetrios; Pagilla, Krishna

2012-01-01

Indoor air quality (IAQ) and odors were determined using sampling/monitoring, measurement, and modeling methods in a large dewatering building at a very large water reclamation plant. The ultimate goal was to determine control strategies to reduce the sensory impacts on the workforce and achieve odor reduction within the building. Study approaches included: (1) investigation of air mixing by using CO(2) as an indicator, (2) measurement of airflow capacity of ventilation fans, (3) measurement of odors and odorants, (4) development of statistical and IAQ models, and (5) recommendation of control strategies. The results showed that air quality in the building complies with occupational safety and health guidelines; however, nuisance odors that can increase stress and productivity loss still persist. Excess roof fan capacity induced odor dispersion to the upper levels. Lack of a local air exhaust system of sufficient capacity and optimum design was found to be the contributor to occasional less than adequate indoor air quality and odors. Overall, air ventilation rate in the building has less effect on persistence of odors in the building. Odor/odorant emission rates from centrifuge drops were approximately 100 times higher than those from the open conveyors. Based on measurements and modeling, the key control strategies recommended include increasing local air exhaust system capacity and relocation of exhaust hoods closer to the centrifuge drops.

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

PubMed

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

2014-09-01

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

Effects of extraneous odors on canine detection

NASA Astrophysics Data System (ADS)

Waggoner, L. Paul; Jones, Meredith H.; Williams, Marc; Johnston, J. M.; Edge, Cindy C.; Petrousky, James A.

1998-12-01

Dogs are often required to detect target substances under challenging conditions. One of these challenges is to detect contraband in the presence of extraneous odors, whether they are part of the ambient environment or placed there for the purpose of evading detection. This paper presents the results of two studies evaluating the ability of dogs to detect target substances in the presence of varying concentrations of extraneous odors. The studies were conducted under behavioral laboratory conditions, providing good control over vapor sources and a clear basis for evaluation of detection responses. Dogs were trained to sample an air stream consisting of the extraneous odor only or the extraneous odor plus the target odor and then press the appropriate lever to earn food. The results are described in terns of the ability of dogs to detect target odors in the presence of a wide range of concentrations of the extraneous odors.

Design and analysis of a pilot scale biofiltration system for odorous air

DOE Office of Scientific and Technical Information (OSTI.GOV)

Classen, J.J.; Young, J.S.; Bottcher, R.W.

2000-02-01

Three pilot-scale biofilters and necessary peripheral equipment were built to clean odorous air from the pit of a swine gestation building at North Carolina State University. A computer measured temperatures, flow rates, and pressure drops. It also controlled and measured the moisture content of a biofilter medium comprised of a 3:1 mixture of yard waste compost to wood chips mixture (by volume). The system was evaluated to ensure that the biofilters would be useful for performing scientific experiments concerning the reduction of swine odor on future research projects. The capability of the biofilters to remove odor was measured using amore » cotton swatch absorption method and an odor panel. The average odor reductions measured by odor intensity, irritation intensity, and unpleasantness for five tests were 61%, 58%, and 84%, respectively. No significant differences in odor reduction performance were found between the biofilters.« less

The effects of passive smoking on olfaction in children.

PubMed

Nageris, B; Hadar, T; Hansen, M C

2002-01-01

The effect of passive smoking on odor identification was studied in 10 children exposed to passive smoke at home. All had at least one parent who smoked at least one pack of cigarettes a day. The control group consisted of 10 children of nonsmoking parents. Ten odorants were tested: vinegar, ammonia, peppermint, roses, bleach, vanilla, cough drops, turpentine, licorice and mothballs. Each child was presented with five test trays containing all 10 odorants in random order. Of the total of 500 odors presented, the control group correctly identified 396 (79%) and the study group, 356 (71%) (p < 0.005). This work demonstrates that children exposed to passive smoke have difficulty identifying odors in comparison to children raised in relatively smoke-free environments. Since the study group tend to misidentify four of the 10 odorants tested--vanilla, roses, mothballs and cough drops--we suggest that these four odorants should suffice in testing odor identification in children.

Odors as cues for orientation to mothers by weanling Virginia opossums

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holmes, D.J.

1992-12-01

Three experiments were conducted to investigate whether whole-body and pouch odors facilitate social cohesion between young Virginia opossums and their mothers just prior to weaning. In experiment 1, young oriented toward plastic buckets containing their mothers, directing significantly higher levels of investigative behavior and more distress vocalizations toward them than toward buckets containing unrelated lactating females. In experiment 2, young oriented toward and investigated empty buckets containing whole-body odors of their mothers more than empty buckets containing odors of other females. Similarly, more investigative behavior was directed toward plastic bucket lids containing pouch odors from subjects mothers than toward pouchmore » odors from unrelated females in experiment 3. These results suggest that social odors help young didelphid marsupials maintain contact with their mothers, as in other mammals, and that whole-body and pouch gland odors are important chemical signals in this nongregarious species.« less

IDENTIFICATION OF ODOR SUBSTANCES IN YAMABUSHITAKE MUSHROOM (Hericium erinaceum) CULTURE MEDIA CONTAINING 'SHOCHU' LEES AND STARCH WASTES, AND BASIC STUDIES ON THEIR DISAPPEARANCE

NASA Astrophysics Data System (ADS)

Yamauchi, Masahito; Matsumoto, Hirotaka; Yamada, Masayoshi; Yagi, Fumio; Murayama, Ryou; Yamaguchi, Yoshinori; Yamaguchi, Takashi

In this study, odor substances from mushroom culture media containing 'shochu' lees and starch wastes were identified and determined. It was apparent that in the media, acetoin, butyric acid and diacetyl were found as main odor substances, and mixed with some other ordor substances to produce unpleasant odor. The main substances disappeared with growth of mycelia. It was not likely that these ordor substances were degraded by extracellular enzymes but suggested that they were degraded by mycelia. Further it was found with the growth of mycelia that odor quality changed from rancid ordor (unpleasant ordor) to mushroom smell (pleasant odor) and the odor index was decreasing.

Selecting odorant compounds to enhance sweet flavor perception by gas chromatography/olfactometry-associated taste (GC/O-AT).

PubMed

Barba, Carmen; Beno, Noelle; Guichard, Elisabeth; Thomas-Danguin, Thierry

2018-08-15

Gas chromatography/olfactometry-associated taste (GC/O-AT) analysis combined with mass spectrometry allowed identification of odorant compounds associated with taste attributes (sweet, salty, bitter and sour) in a multi-fruit juice. Nine compounds were selected for their odor-associated sweetness enhancement in a multi-fruit juice odor context using Olfactoscan and for their odor-induced sweet taste enhancement in sucrose solution and sugar-reduced fruit juice through sensory tests. Sweetness of the fruit juice odor was significantly enhanced by methyl 2-methylbutanoate, ethyl butanoate, ethyl 2-methylbutanoate and linalool; sweet perception was significantly enhanced in 7% sucrose solution by ethyl 2-methylbutanoate, furaneol and γ-decalactone, and in 32% sugar-reduced fruit juice by ethyl 2-methylbutanoate. GC/O-AT analysis is a novel, efficient approach to select odorants associated with a given taste. The further screening of taste-associated odorants by Olfactoscan helps to identify the most efficient odorants to enhance a target taste perception and may be used to find new ways to modulate taste perception in foods and beverages. Copyright © 2018 Elsevier Ltd. All rights reserved.

Identification of Odorant-Receptor Interactions by Global Mapping of the Human Odorome

PubMed Central

Audouze, Karine; Tromelin, Anne; Le Bon, Anne Marie; Belloir, Christine; Petersen, Rasmus Koefoed; Kristiansen, Karsten; Brunak, Søren; Taboureau, Olivier

2014-01-01

The human olfactory system recognizes a broad spectrum of odorants using approximately 400 different olfactory receptors (hORs). Although significant improvements of heterologous expression systems used to study interactions between ORs and odorant molecules have been made, screening the olfactory repertoire of hORs remains a tremendous challenge. We therefore developed a chemical systems level approach based on protein-protein association network to investigate novel hOR-odorant relationships. Using this new approach, we proposed and validated new bioactivities for odorant molecules and OR2W1, OR51E1 and OR5P3. As it remains largely unknown how human perception of odorants influence or prevent diseases, we also developed an odorant-protein matrix to explore global relationships between chemicals, biological targets and disease susceptibilities. We successfully experimentally demonstrated interactions between odorants and the cannabinoid receptor 1 (CB1) and the peroxisome proliferator-activated receptor gamma (PPARγ). Overall, these results illustrate the potential of integrative systems chemical biology to explore the impact of odorant molecules on human health, i.e. human odorome. PMID:24695519

Odors as cues for the recall of words unrelated to odor.

PubMed

Morgan, C L

1996-12-01

The effectiveness of an ambient odor as a retrieval cue for words unrelated to odor was investigated. After incidental learning of 40 adjectives, 40 participants were tested for recall during three unannounced recall phases (15 min., 48 hr., and 5 days). Participants in two control conditions learned with no odor present and either had no odor present during any recall phase or only during recall after 5 days. Participants in two conditions learned with an odor present and either had the odor present during recall only after 5 days or during recall both after 15 min. and after 5 days. Analyses indicated that, while participants in the control conditions recalled significantly less during each succeeding recall phase, recall by participants in the two experimental conditions did not decrease significantly. Recall by participants in the two experimental conditions was significantly higher during recall after 5 days (when the odor was reintroduced) than either control group. The addition of a salient cue during learning and retrieval facilitated recall more than the presence of constant environmental cues.

Odor from a chemical perspective

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wray, T.K.

1995-06-01

Early odor-detection measurements categorized chemicals according to odor quality. Recent methods focus on the odor threshold, or the quantitative amount of a chemical in air that can be detected by the human sense of smell. Researchers characterize and quantify odor using an array of sensory and analytical procedures. Humans possess one of the dullest mammalian senses of smell; however, they can recognize about 10,000 distinct odors at concentrations ranging from less than 1 part per billion to several hundred thousand parts per million. Each time humans inhale, they chemically analyze microscopic pieces of the environment that make physical contact withmore » the nerves in their noses. Individual molecules travel up the nose to a sheet of moist, mucus-bathed tissue that consists of about 5 million smell-sensing, olfactory neurons. After dissolving in the mucus, odor molecules ``float`` into appropriately shaped receptor pockets. A series of cellular reactions then transmit impulses to the limbic system, hippocampus and, finally, the neocortex. Odor detection is an important defense mechanism. The author presents the odor thresholds for selected organic compounds, and other hazardous chemicals.« less

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

PubMed

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

2017-11-29

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

Extracting the Behaviorally Relevant Stimulus: Unique Neural Representation of Farnesol, a Component of the Recruitment Pheromone of Bombus terrestris

PubMed Central

Strube-Bloss, Martin F.; Brown, Austin; Spaethe, Johannes; Schmitt, Thomas; Rössler, Wolfgang

2015-01-01

To trigger innate behavior, sensory neural networks are pre-tuned to extract biologically relevant stimuli. Many male-female or insect-plant interactions depend on this phenomenon. Especially communication among individuals within social groups depends on innate behaviors. One example is the efficient recruitment of nest mates by successful bumblebee foragers. Returning foragers release a recruitment pheromone in the nest while they perform a ‘dance’ behavior to activate unemployed nest mates. A major component of this pheromone is the sesquiterpenoid farnesol. How farnesol is processed and perceived by the olfactory system, has not yet been identified. It is much likely that processing farnesol involves an innate mechanism for the extraction of relevant information to trigger a fast and reliable behavioral response. To test this hypothesis, we used population response analyses of 100 antennal lobe (AL) neurons recorded in alive bumblebee workers under repeated stimulation with four behaviorally different, but chemically related odorants (geraniol, citronellol, citronellal and farnesol). The analysis identified a unique neural representation of the recruitment pheromone component compared to the other odorants that are predominantly emitted by flowers. The farnesol induced population activity in the AL allowed a reliable separation of farnesol from all other chemically related odor stimuli we tested. We conclude that the farnesol induced population activity may reflect a predetermined representation within the AL-neural network allowing efficient and fast extraction of a behaviorally relevant stimulus. Furthermore, the results show that population response analyses of multiple single AL-units may provide a powerful tool to identify distinct representations of behaviorally relevant odors. PMID:26340263

Classification of human pathogen bacteria for early screening using electronic nose

NASA Astrophysics Data System (ADS)

Zulkifli, Syahida Amani; Mohamad, Che Wan Syarifah Robiah; Abdullah, Abu Hassan

2017-10-01

This paper present human pathogen bacteria for early screening using electronic nose. Electronic nose (E-nose) known as gas sensor array is a device that analyze the odor measurement give the fast response and less time consuming for clinical diagnosis. Many bacterial pathogens could lead to life threatening infections. Accurate and rapid diagnosis is crucial for the successful management of these infections disease. The conventional method need more time to detect the growth of bacterial. Alternatively, the bacteria are Pseudomonas aeruginosa and Shigella cultured on different media agar can be detected and classifies according to the volatile compound in shorter time using electronic nose (E-nose). Then, the data from electronic nose (E-nose) is processed using statistical method which is principal component analysis (PCA). The study shows the capability of electronic nose (E-nose) for early screening for bacterial infection in human stomach.

Marked dissociation between hypothalamic-pituitary-adrenal activation and long-term behavioral effects in rats exposed to immobilization or cat odor.

PubMed

Muñoz-Abellán, C; Andero, R; Nadal, R; Armario, A

2008-09-01

Exposure of rodents to cats or certain cat odors results in long-term behavioral effects reminiscent of enhanced anxiety that have been considered to model post-traumatic stress disorder. However, other severe stressors such as tail-shock or immobilization in wooden boards (IMO) appear to induce shorter lasting changes in anxiety. In addition, there are controversial results regarding the effects of urine/feces odors. In the present work, we studied in two experiments the relationship between the degree of stress experienced by the animals during exposure to IMO, urine odors or fur odors (as assessed by hypothalamic-pituitary-adrenal activation and plasma glucose) and the short- and long-term behavioral consequences. In the first experiment, rats were individually exposed for 15 min to a novel environment (white large cages) containing either clean cat litter (controls) or litter soiled by cats (urine odors). Half of the rats in each condition were left to freely explore the environment whereas the others were subjected to immobilization (IMO) within the cages. Although ACTH, corticosterone and glucose responses to IMO were much stronger than those to the white cages with clean litter or urine odors (which did not differ from each other), no effect of treatments on anxiety-like behavior in the elevated plus-maze (EPM) were found one week later. However, previous IMO exposure did cause sensitization of the ACTH response to the EPM. In the second experiment, the response to white large cages containing either no odor (controls), litter soiled by cats (urine odor) or a cloth impregnated with cat odor (fur odor) was compared. Urine and fur odors elicited similar ACTH and corticosterone responses that were higher than those of controls, but plasma glucose levels were slightly higher in rats exposed to fur odor. When compared to controls, activity was only diminished in the novel cages containing fur odor. Similarly, fur odor-exposed rats, but not those exposed to urine odor, showed signs of enhanced anxiety in the EPM seven days later, although the ACTH response to the EPM was similar in the three groups. The present data demonstrate: (a) a marked dissociation between the degree of ACTH, corticosterone and glucose responses to stressors and their long-term anxiety-like effects; (b) that the type of cat odor is critical in determining the short-term and long-term physiological and behavioral consequences of exposure; and (c) that plasma ACTH released during brief exposure to the EPM does not appear to reflect anxiety-like behavior.

Combining Ordinary Kriging with wind directions to identify sources of industrial odors in Portland, Oregon.

PubMed

Eckmann, Ted C; Wright, Samantha G; Simpson, Logan K; Walker, Joe L; Kolmes, Steven A; Houck, James E; Velasquez, Sandra C

2018-01-01

This study combines Ordinary Kriging, odor monitoring, and wind direction data to demonstrate how these elements can be applied to identify the source of an industrial odor. The specific case study used as an example of how to address this issue was the University Park neighborhood of Portland, Oregon (USA) where residents frequently complain about industrial odors, and suspect the main source to be a nearby Daimler Trucks North America LLC manufacturing plant. We collected 19,665 odor observations plus 105,120 wind measurements, using an automated weather station to measure winds in the area at five-minute intervals, logging continuously from December 2014 through November 2015, while we also measured odors at 19 locations, three times per day, using methods from the American Society of the International Association for Testing and Materials. Our results quantify how winds vary with season and time of day when industrial odors were observed versus when they were not observed, while also mapping spatiotemporal patterns in these odors using Ordinary Kriging. Our analyses show that industrial odors were detected most frequently to the northwest of the Daimler plant, mostly when winds blew from the southeast, suggesting Daimler's facility is a likely source for much of this odor.

The olfactory hole-board test in rats: a new paradigm to study aversion and preferences to odors

PubMed Central

Wernecke, Kerstin E. A.; Fendt, Markus

2015-01-01

Odors of biological relevance (e.g., predator odors, sex odors) are known to effectively influence basic survival needs of rodents such as anti-predatory defensiveness and mating behaviors. Research focused on the effects of these odors on rats’ behavior mostly includes multi-trial paradigms where animals experience single odor exposures in subsequent, separated experimental sessions. In the present study, we introduce a modification of the olfactory hole-board test that allows studying the effects of different odors on rats’ behavior within single trials. First, we demonstrated that the corner holes of the hole-board were preferentially visited by rats. The placement of different odors under the corner holes changed this hole preference. We showed that holes with carnivore urine samples were avoided, while corner holes with female rat urine samples were preferred. Furthermore, corner holes with urine samples from a carnivore, herbivore, and omnivore were differentially visited indicating that rats can discriminate these odors. To test whether anxiolytic treatment specifically modulates the avoidance of carnivore urine holes, we treated rats with buspirone. Buspirone treatment completely abolished the avoidance of carnivore urine holes. Taken together, our findings indicate that the olfactory hole-board test is a valuable tool for measuring avoidance and preference responses to biologically relevant odors. PMID:26379516

Composition of key offensive odorants released from fresh food materials

NASA Astrophysics Data System (ADS)

Kim, Ki-Hyun; Kim, Yong-Hyun

2014-06-01

A refrigerator loaded with a variety of foods without sealed packaging can create quite an olfactory nuisance, and it may come as a surprise that fresh foods emit unpleasant odorants just as those that are decaying. To learn more about nuisance sources in our daily lives, we measured a list of 22 compounds designated as the key offensive odorants (e.g., reduced sulfur, nitrogenous, volatile fatty acid (VFA), and carbonyls) from nine types of common food items consumed in S. Korea: raw beef, raw fish, spam, yolks and albumin of boiled eggs (analyzed separately), milk, cheese, onions, and strawberries. The odor intensity (OI) of each food item was computed initially with the aid of previously used empirical equations. This indicates that the malodor properties of target foods tend to be governed by a few key odorants such as VFA, S, and N compounds. The extent of odorant mixing of a given food was then evaluated by exploring the correlation between the human olfaction (e.g., dilution-to-threshold (D/T) ratio) and the odor potential determined indirectly (instrumentally) such as odor activity value (OAV) or sum of odor intensity (SOI). The overall results of our study confirm the existence of malodorant compounds released from common food items and their contribution to their odor characteristics to a certain degree.

Family scents: developmental changes in the perception of kin body odor?

PubMed

Ferdenzi, Camille; Schaal, Benoist; Roberts, S Craig

2010-08-01

There is increasing evidence that human body odors are involved in adaptive behaviors, such as parental attachment in infants or partner choice in adults. The aim of the present study was to investigate changes in body-odor perception around puberty, a period largely ignored for odor-mediated behavioral changes, despite major changes in social needs and in odor emission and perception. Nine families with two children (8 pre-pubertal, aged 7-10, and 10 pubertal, aged 11-18) evaluated body odors of family members and unfamiliar individuals for pleasantness, intensity, and masculinity, and performed a recognition task. The hypothesized emergence of a parent-child mutual aversion for the odor of opposite-sex family members at puberty was not found, contradicting one of the few studies on the topic (Weisfeld et al., J. Exp. Child Psychol. 85:279-295, 2003). However, some developmental changes were observed, including reduced aversion for odor of the same-sex parent, and increased ability of adults, compared to children, to recognize odor of family members. Sex and personality (depressive and aggressive traits) also significantly influenced odor judgments. Further research with larger samples is needed to investigate the poorly explored issue of how olfactory perception of self and family members develops, and how it could correlate with normal reorganizations in social interactions at adolescence.

Behavioral responses to odors from other species: introducing a complementary model of allelochemics involving vertebrates

PubMed Central

Nielsen, Birte L.; Rampin, Olivier; Meunier, Nicolas; Bombail, Vincent

2015-01-01

It has long been known that the behavior of an animal can be affected by odors from another species. Such interspecific effects of odorous compounds (allelochemics) are usually characterized according to who benefits (emitter, receiver, or both) and the odors categorized accordingly (allomones, kairomones, and synomones, respectively), which has its origin in the definition of pheromones, i.e., intraspecific communication via volatile compounds. When considering vertebrates, however, interspecific odor-based effects exist which do not fit well in this paradigm. Three aspects in particular do not encompass all interspecific semiochemical effects: one relates to the innateness of the behavioral response, another to the origin of the odor, and the third to the intent of the message. In this review we focus on vertebrates, and present examples of behavioral responses of animals to odors from other species with specific reference to these three aspects. Searching for a more useful classification of allelochemical effects we examine the relationship between the valence of odors (attractive through to aversive), and the relative contributions of learned and unconditioned (innate) behavioral responses to odors from other species. We propose that these two factors (odor valence and learning) may offer an alternative way to describe the nature of interspecific olfactory effects involving vertebrates compared to the current focus on who benefits. PMID:26161069

Combining Ordinary Kriging with wind directions to identify sources of industrial odors in Portland, Oregon

PubMed Central

Kolmes, Steven A.; Houck, James E.; Velasquez, Sandra C.

2018-01-01

This study combines Ordinary Kriging, odor monitoring, and wind direction data to demonstrate how these elements can be applied to identify the source of an industrial odor. The specific case study used as an example of how to address this issue was the University Park neighborhood of Portland, Oregon (USA) where residents frequently complain about industrial odors, and suspect the main source to be a nearby Daimler Trucks North America LLC manufacturing plant. We collected 19,665 odor observations plus 105,120 wind measurements, using an automated weather station to measure winds in the area at five-minute intervals, logging continuously from December 2014 through November 2015, while we also measured odors at 19 locations, three times per day, using methods from the American Society of the International Association for Testing and Materials. Our results quantify how winds vary with season and time of day when industrial odors were observed versus when they were not observed, while also mapping spatiotemporal patterns in these odors using Ordinary Kriging. Our analyses show that industrial odors were detected most frequently to the northwest of the Daimler plant, mostly when winds blew from the southeast, suggesting Daimler’s facility is a likely source for much of this odor. PMID:29385136

Cross-Cultural Color-Odor Associations

PubMed Central

Levitan, Carmel A.; Ren, Jiana; Woods, Andy T.; Boesveldt, Sanne; Chan, Jason S.; McKenzie, Kirsten J.; Dodson, Michael; Levin, Jai A.; Leong, Christine X. R.; van den Bosch, Jasper J. F.

2014-01-01

Colors and odors are associated; for instance, people typically match the smell of strawberries to the color pink or red. These associations are forms of crossmodal correspondences. Recently, there has been discussion about the extent to which these correspondences arise for structural reasons (i.e., an inherent mapping between color and odor), statistical reasons (i.e., covariance in experience), and/or semantically-mediated reasons (i.e., stemming from language). The present study probed this question by testing color-odor correspondences in 6 different cultural groups (Dutch, Netherlands-residing-Chinese, German, Malay, Malaysian-Chinese, and US residents), using the same set of 14 odors and asking participants to make congruent and incongruent color choices for each odor. We found consistent patterns in color choices for each odor within each culture, showing that participants were making non-random color-odor matches. We used representational dissimilarity analysis to probe for variations in the patterns of color-odor associations across cultures; we found that US and German participants had the most similar patterns of associations, followed by German and Malay participants. The largest group differences were between Malay and Netherlands-resident Chinese participants and between Dutch and Malaysian-Chinese participants. We conclude that culture plays a role in color-odor crossmodal associations, which likely arise, at least in part, through experience. PMID:25007343

Fancy Citrus, Feel Good: Positive Judgment of Citrus Odor, but Not the Odor Itself, Is Associated with Elevated Mood during Experienced Helplessness

PubMed Central

Hoenen, Matthias; Müller, Katharina; Pause, Bettina M.; Lübke, Katrin T.

2016-01-01

Aromatherapy claims that citrus essential oils exert mood lifting effects. Controlled studies, however, have yielded inconsistent results. Notably, studies so far did not control for odor pleasantness, although pleasantness is a critical determinant of emotional responses to odors. This study investigates mood lifting effects of d-(+)-limonene, the most prominent substance in citrus essential oils, with respect to odor quality judgments. Negative mood was induced within 78 participants using a helplessness paradigm (unsolvable social discrimination task). During this task, participants were continuously (mean duration: 19.5 min) exposed to d-(+)-limonene (n = 25), vanillin (n = 26), or diethyl phthalate (n = 27). Participants described their mood (Self-Assessment-Manikin, basic emotion ratings) and judged the odors’ quality (intensity, pleasantness, unpleasantness, familiarity) prior to and following the helplessness induction. The participants were in a less positive mood after the helplessness induction (p < 0.001), irrespective of the odor condition. Still, the more pleasant the participants judged the odors, the less effective the helplessness induction was in reducing happiness (p = 0.019). The results show no odor specific mood lifting effect of d-(+)-limonene, but indicate a positive effect of odor pleasantness on mood. The study highlights the necessity to evaluate odor judgments in aromatherapy research. PMID:26869973

Odorants selectively activate distinct G protein subtypes in olfactory cilia.

PubMed

Schandar, M; Laugwitz, K L; Boekhoff, I; Kroner, C; Gudermann, T; Schultz, G; Breer, H

1998-07-03

Chemoelectrical signal transduction in olfactory neurons appears to involve intracellular reaction cascades mediated by heterotrimeric GTP-binding proteins. In this study attempts were made to identify the G protein subtype(s) in olfactory cilia that are activated by the primary (odorant) signal. Antibodies directed against the alpha subunits of distinct G protein subtypes interfered specifically with second messenger reponses elicited by defined subsets of odorants; odor-induced cAMP-formation was attenuated by Galphas antibodies, whereas Galphao antibodies blocked odor-induced inositol 1,4, 5-trisphosphate (IP3) formation. Activation-dependent photolabeling of Galpha subunits with [alpha-32P]GTP azidoanilide followed by immunoprecipitation using subtype-specific antibodies enabled identification of particular individual G protein subtypes that were activated upon stimulation of isolated olfactory cilia by chemically distinct odorants. For example odorants that elicited a cAMP response resulted in labeling of a Galphas-like protein, whereas odorants that elicited an IP3 response led to the labeling of a Galphao-like protein. Since odorant-induced IP3 formation was also blocked by Gbeta antibodies, activation of olfactory phospholipase C might be mediated by betagamma subunits of a Go-like G protein. These results indicate that different subsets of odorants selectively trigger distinct reaction cascades and provide evidence for dual transduction pathways in olfactory signaling.

Source and specificity of chemical cues mediating shelter preference of Caribbean spiny lobsters (Panulirus argus).

PubMed

Horner, Amy J; Nickles, Scott P; Weissburg, Marc J; Derby, Charles D

2006-10-01

Caribbean spiny lobsters display a diversity of social behaviors, one of the most prevalent of which is gregarious diurnal sheltering. Previous research has demonstrated that shelter selection is chemically mediated, but the source of release and the identity of the aggregation signal are unknown. In this study, we investigated the source and specificity of the aggregation signal in Caribbean spiny lobsters, Panulirus argus. We developed a relatively rapid test of shelter choice in a 5000-l laboratory flume that simulated flow conditions in the spiny lobster's natural environment, and used it to examine the shelter preference of the animals in response to a variety of odorants. We found that both males and females associated preferentially with shelters emanating conspecific urine of either sex, but not with shelters emanating seawater, food odors, or the scent of a predatory octopus. These results demonstrate specificity in the cues mediating sheltering behavior and show that urine is at least one source of the aggregation signal.