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Results for “Olfactory Perception”

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At least 145 records · Page 8Linked to original sources

PubMed2007

Women's hedonic ratings of body odor of heterosexual and homosexual men.

Men's body odor influences women's mate choice and individual variation among traits affects hedonic perceptions of this odor (e.g., immune system characteristics). Previous research by Sergeant (2002) indicated that one such characteristic is sexual orientation: body odor from homosexual men was perceived by heterosexual women as more hedonically pleasing than that of heterosexual men. The current study re-examined the influence of men's sexual orientation on women's perceptions of body odor. Homosexual (n=10) and heterosexual (n=9) men produced samples of body odor using T-shirts under equivalent environmental conditions. Heterosexual women (n=35) rated these samples, and a set of unused T-shirts, using a series of hedonic scales. Women rated the body odor of homosexual men as being comparatively more pleasant, sexier, and more preferable than that of heterosexual men but not significantly different from the unused T-shirts. This finding was consistent with contemporary research demonstrating that an individual's sexual orientation significantly impacts their olfactory function, both in terms of body odor production and olfactory perceptions of certain compounds.

Adult↗

PubMed1990

Abnormal perceptual experiences in migraine.

The prevalence of abnormal perceptual experiences as symptoms of migraine attacks was determined in a consecutive series of 46 new female referrals to a migraine clinic. All patients met the diagnostic criteria of the International Headache Society for migraine with aura or migraine without aura and had no other serious physical illness. Seven patients (15%) reported abnormal perceptions (olfactory and/or gustatory hallucinations and distortions of body image) as part of most migraine attacks. A statistically significant association was found between these abnormal perceptual experiences and complaints of mood change, particularly increased depression and irritability, as part of most migraine attacks. It is suggested that spreading depression of cortical electrical activity may be responsible for the manifestations of temporal lobe and limbic system dysfunction.

Adolescent↗

PubMed2002

[Post-traumatic anosmia: description of a clinical case, proposal of a standardized protocol and medico-legal comments].

Man's olfactory perception is considerably limited compared to that of other animals; this sense is, however, extremely important in our social lives: it helps us to "savour" our food, it enables us to appreciate perfumes and, even more important, to pick up smells that signal a danger, such as a gas leak or a fire. We describe the clinical case of a patient with anosmia and hypogeusia that appeared immediately after suffering a concussive head injury. We go through the diagnostic protocol for medico-legal assessment of hypoanosmias previously described in the literature, which includes a clinical and an imaging section. In 9% of all anosmic patients, a traumatic event precedes the onset of the disorder, with repercussions on the olfactory channels and centres of the peripherical and/or central nervous system. The overall rate of anosmia following head injury is estimated to be around 7.5%. Among the principal causes of anosmia, those of medico-legal interest constitute 35% of the total. On the basis of our personal experience and of clinical studies conducted by other Authors, we propose that a bioptic investigation of the olfactory mucosa be added to the existing protocol. The olfactory neuroepithelium of patients suffering from post-traumatic anosmia, in fact, evidences some characteristic degenerative aspects. In conclusion, we report several comments regarding the quantification of the reduction of the olfactory function in different areas of medico-legal interest.

Adult↗

PubMed2006

An in vivo technique for pharmacological manipulation of Drosophila brain during optical recording.

Drosophila melanogaster, an established model for genetic manipulation, has recently been used for studying olfactory perception, learning, and memory. Some of these important behavioral phenomena have been dissected with defined mutants, some to a single biochemical lesion, expressed in central brain structures known as the mushroom bodies. A previously introduced preparation used a window in the head capsule through which these structures could be imaged using genetically expressed fluorescent calcium sensors while applying physiological odorant stimuli. Unfortunately, technical constraints prevented direct manipulation of the mushroom bodies with this preparation. I describe here a preparation that will allow, for the first time, the direct pharmacological manipulation of these important structures during imaging in the living adult fly. Responses to discreet applications of acetylcholine were reversibly blocked with tubocurare and reversibly eliminated in calcium-free Ringers. This new technique will significantly enhance the usefulness of the Drosophila model system, allowing a more quantitative examination of the mechanisms involved in olfactory learning and memory.

Acetylcholine↗

PubMed1996

The role of the piriform cortex in kindling.

In epilepsy research, there is growing interest in the role of the piriform cortex (PC) in the development and maintenance of limbic kindling and other types of limbic epileptogenesis leading to complex partial seizures, i.e. the most common type of seizures in human epilepsy. The PC ("primary olfactory cortex") is the largest area of the mammalian olfactory cortex and receives direct projections from the olfactory bulb via the lateral olfactory tract (LOT). Beside the obvious involvement in olfactory perception and discrimination, the PC, because of its unique intrinsic associative fiber system and its various connections to and from other limbic nuclei, has been implicated in the study of memory processing, spread of excitatory waves, and in the study of brain disorders such as epilepsy with particular emphasis on the kindling model of temporal lobe epilepsy with complex partial seizures. The interest in the kindling model is based primarily on the following observations. (1) The PC contains the most susceptible neural circuits of all forebrain regions for electrical (or chemical) induction of limbic seizures. (2) During electrical stimulation of other limbic brain regions, broad and large afterdischarges can be observed in the ipsilateral PC, indicating that the PC is activated early during the kindling process. (3) The interictal discharge, which many consider to be the hallmark of epilepsy, originates in the PC, independent of which structure serves as the kindled focus. (4) Autoradiographic studies of cerebral metabolism in rat amygdala kindling show that, during focal seizures, the area which exhibits the most consistent increase in glucose utilization is the ipsilateral paleocortex, particularly the PC. (5) During the commonly short initial afterdischarges induced by stimulation of the amygdala at the early stages of kindling, the PC is the first region that exhibits induction of immediate-early genes, such as c-fos. (6) The PC is the most sensitive brain structure to brain damage by continuous or frequent stimulation of the amygdala or hippocampus. (7) Amygdala kindling leads to a circumscribed loss of GABAergic neurons in the ipsilateral PC, which is likely to explain the increase in excitability of PC pyramidal neurons during kindling. (8) Kindling of the amygdala or hippocampus induces astrogliosis in the PC, indicating neuronal death in this brain region. Furthermore, activation of microglia is seen in the PC after amygdala kindling. (9) Complete bilateral lesions of the PC block the generalization of seizures upon kindling from the hippocampus or olfactory bulb. Incomplete or unilateral lesions are less effective in this regard, but large unilateral lesions of the PC and adjacent endopiriform nucleus markedly increase the threshold for induction of focal seizures from stimulation of the basolateral amygdala (BLA) prior to and after kindling, indicating that the PC critically contributes to regulation of excitability in the amygdala. (10) Potentiation of GABAergic neurotransmission in the PC markedly increases the threshold for induction of kindled seizures via stimulation of the BLA, again indicating a critical role of the PC in regulation of seizure susceptibility of the amygdala. Microinjections of NMDA antagonists or sodium channel blockers into the PC block seizure generalization during kindling development. (11) Neurophysiological studies on the amygdala-PC slice preparation from kindled rats showed that kindling of the amygdala induces long-lasting changes in synaptic efficacy in the ipsilateral PC, including spontaneous discharges and enhanced susceptibility to evoked burst responses. The epileptiform potentials in PC slice preparations from kindled rats seem to originate in neuron at the deep boundary of PC. Spontaneous firing and enhanced excitability of PC neurons in response to kindling from other sites is also seen in vivo, substantiating the fact that kindling induces long-lasting changes in the PC c

Animals↗

PubMed2005

Functional characterization of two human olfactory receptors expressed in the baculovirus Sf9 insect cell system.

Olfactory receptors (ORs) are the largest member of the G-protein-coupled receptors which mediate early olfactory perception in discriminating among thousands of odorant molecules. Assigning odorous ligands to ORs is a prerequisite to gaining an understanding of the mechanisms of odorant recognition. The functional expression of ORs represents a critical step in addressing this issue. Due to limitations in heterologous expression, very few mammal ORs have been characterized, and so far only one is from human origin. Consequently, OR function still remains poorly understood, especially in humans, whose genome encodes a restricted chemosensory repertoire compared with most mammal species. In this study, we have designed cassette baculovirus vectors to coexpress human OR 17-209 or OR 17-210 with either G(alpha olf) or G(alpha16) proteins in Sf9 cells. Each OR was found to be expressed at the cell surface and colocalized with both G(alpha) proteins. Using Ca2+ imaging, we showed that OR 17-209 and OR 17-210 proteins are activated by esters and ketones respectively. Odorant-induced calcium response was increased when ORs were coexpressed with G(alpha16) protein, whereas coexpression with G(alpha olf) abolished calcium signaling. This strategy has been found to overcome most of the limitations encountered when expressing an OR protein and has permitted odorant screening of functional ORs. Our approach could thus be of interest for further expression and ligand assignment of other orphan receptor proteins.

Animals↗

PubMed1975

Olfaction in the development of social preferences in the human neonate.

Olfactory perception in the human neonate has been largely ignored. The present experiments examine the possibility that neonates can use smell to locate a food source and that they can differentiate between their own mother and another mother on the basis of smell. Head-turning to breast pads was used in perference tests. Although the neonate did not appear to be able to use smell to localize a food source, significantly more babies spent more time turning towards their own mother's breast pad than towards a clean breast pad at five days of age. By six days of age babies were showing a differential response between their own mother's breast pad and another mother's breast pad, although this differentiation was not present at two days of age.

Age Factors↗

PubMed1994

Nervous system dysfunction among workers with long-term exposure to manganese.

Neurological disorders, bearing many similarities to Parkinson's disease, have been associated with environmental and occupational exposure to manganese (Mn). To document early nervous system dysfunction associated with long-term exposure to Mn, a battery of neurofunctional tests was administered to workers employed in Mn alloy production. Study participation was 95% (n = 115). A matched pair design was used; actively working men, with no history of workplace exposure to neurotoxins, were recruited from the region as referents. Matching was done on the variables: age (+/- 3 years), educational level (+/- 2 years), smoking status, and number of children. Stationary environmental sampling indicated that Mn levels varied widely (geometric means: Mn dust, 0.89 mg/m3; respirable Mn, 0.04 mg/m3). The alloy workers had significantly higher levels of whole blood Mn (geometric mean: 1.03 microgram/100 ml vs 0.68 microgram/100 ml); no differences were observed for urinary Mn. Univariate analysis (paired t test, Signed Rank and McNemar) and multivariate analysis of variance (Hotelling-Lawley statistic) revealed that the pairs differed on symptom reporting, emotional state, motor functions, cognitive flexibility, and olfactory perception threshold; verbal fluency, basic mathematics, reading capability, and attentional capacity were similar. These findings are consistent with current knowledge on brain Mn activity and suggest that manifestations of early manganism can be observed in well designed population studies, using sensitive testing methods.

Adult↗

PubMed1997

Motor function, olfactory threshold, and hematological indices in manganese-exposed ferroalloy workers.

A cross-sectional study was conducted in 35 male subjects randomly selected from workers of a ferroalloy production plant and exposed to manganese (Mn) oxides; the objective was to detect early signs of neurologic impairment. The subjects' mean age was 39.4 years (SD, 8. 4); the average exposure duration was 14.5 years (range, 5-29 years). A control group of industrial workers not exposed to neurotoxic chemicals and comparable in age and confounding factors was recruited. The intensity of Mn exposure was moderate, as reflected by airborne Mn concentrations in total dust averaging 193 [corrected] micro g/m3. Mn levels in blood (MnB) and urine (MnU) were significantly higher in the Mn-exposed workers than in control workers. A relationship (not found with MnU) was found between MnB and a cumulative exposure index calculated on the basis of air concentration and exposure history for each subject (r = 0.52; r2 = 0.27; P = 0.002). Psychomotor function scores were lower among Mn-exposed subjects. The Aiming score was negatively correlated with MnB in the exposed group. The olfactory threshold did not differ between the two groups, although it was negatively associated with MnU in the exposed group. The white blood cell count results were significantly higher in Mn-exposed subjects than in controls. These findings show that an increase in Mn body burden is associated with an impairment of motor functions, whereas the increased excretion of Mn is related to an increased olfactory perception. Changes in numbers of leukocytes could indicate possible interferences of Mn with the immunological system.

Air Pollutants, Occupational↗

PubMed2002

Psychological effects of musky compounds: comparison of androstadienone with androstenol and muscone.

Previously, we have shown that delta4,16-androstadien-3-one modulates psychological state, reducing negative mood and increasing positive mood (Jacob and McClintock, 2000; Jacob et al., 2001a). In order to determine whether similar musky compounds also produce these effects, we compared the effects of androstadienone to those of androstenol and muscone, measuring the psychological states of 37 participants. Androstenol and muscone were chosen because they too have a musky odor at high concentrations, while androstenol is a steroid like androstadienone and muscone is not. In a controlled laboratory setting, we conducted a double-blind, within-subject, repeated-measures experiment counterbalanced for order of presentation. Under each participant's nose, a nanomolar amount of each compound was presented, masked by clove oil to minimize perceptible olfactory differences. Participants completed a baseline psychological battery and twice again at 25-min intervals after exposure. Androstadienone's effects on psychological state were unique in comparison with those of androstenol and with muscone. Exposure through passive inhalation, rather than dermal contact, was sufficient for these effects. Although this is additional evidence that androstadienone may be a pheromone, it is yet to be determined whether humans exude concentrations into the air adequate for social communication or process this chemical information within natural social contexts.

Administration, Inhalation↗

PubMed1995

Neuroanatomical and functional specificity of the basolateral amygdaloid nucleus in taste-potentiated odor aversion.

The present study aimed at documenting the neurobiological substrate of taste-potentiated odor aversion (TPOA) in the rat. The role of several temporal lobe structures in discriminative TPOA learning was questioned. The effects of excitotoxic lesions (ibotenate) of the basolateral amygdaloid nucleus, the central amygdaloid nucleus, the caudate putamen nucleus, and aspirative lesion of the entorhinal cortex were studied. The results show that only basolateral amygdaloid nucleus (ABL) damage impaired TPOA. This effect was selective of TPOA, since it spared conditioned taste aversion (CTA) and olfactory perception. In order to find out which process in TPOA requires normal functioning of the ABL, the effects of microinjections of a GABAA agonist (muscimol) into the ABL at various stages of the experiment were examined. The results show that application of muscimol during the acquisition, before or after the presentation of the odor-taste stimulus, impaired TPOA without affecting CTA. Contrastingly, application of muscimol before the test impaired neither TPOA nor CTA. These results suggest that ABL is involved in the acquisition but not in the retrieval of TPOA. The efficacy of muscimol microinjected after the presentation of the odor-taste stimulus further suggests that the deficit is not due to a sensory impairment but rather to the disruption of a memory process, critical for TPOA.

Amygdala↗

PubMed1988

[Navigation by means of an olfactory map and a sun compass: the homing ability of pigeons].

Pigeon homing, investigated as a paradigmatic example of bird navigation, appears to be based on two mechanisms of orientation whose functions correspond to those of map and compass. Tasks of the latter are usually accomplished by a sun compass, taking into account the sun's movement and time of day. Under overcast skies, the magnetic field of the earth may be used for compass orientation. The "map" part of the system, responsible for site localization, makes use of olfactory perception of atmospheric trace compounds, which must be concluded to contain positional information in unfamiliar areas up to several hundreds of kilometers from home.

Animals↗

PubMed1995

Cholinergic modulation of a decrement in social investigation following repeated contacts between mice.

Social recognition has been inferred from a decline in olfactory investigation of conspecific intruders during repeated or protracted confrontation with a resident rat. A stimulus-response relationship defined by lack of response remains somewhat ambiguous. Since it is likely that behavior continues to be emitted by the resident animal, how behavior reorganizes as the resident becomes familiar with an intruder represents an important issue in the characterization of recognition. We examined the decline in olfactory investigation of ovariectomized females by adult male mice. The duration and frequency of olfactory investigation was measured during four 1 minute confrontations with 10-min intertrial intervals (Training trials). If the same female was presented in each trial, investigation declined to less than 50% of initial levels. Aggressive behavior gradually increased with repeated trials. No decline in investigation or increased aggression was measured when females were changed in each trial. Administration of doses of scopolamine (0.16-1.0 mg/kg, IP) blocked decrements in olfactory investigation in repeated confrontations and significantly reduced aggression. Co-administration of heptylphysostigmine (0.32-5.0 mg/kg, IP) reversed scopolamine's effects on olfactory investigation but not aggression. Acetylcholinesterase inhibitors heptylphysostigmine, galanthamine (0.63-2.5 mg/kg, IP) and tacrine (0.63-10.0 mg/kg, IP) all enhanced the rate of decrement of olfactory investigation when administered alone, but had differential effects on aggression. The decline in investigation corresponds to criteria for habituation. Increased responsivity expressed as aggression indicates recognition may also be characterized as a change in behavioral strategy dependent on the sexual and social status of the stimulus animal. Pharmacological data support a role for acetylcholine release in the development of social recognition as an olfactory memory, or through modulation of olfactory perception.

Aggression↗

PubMed2006

Repetitive endoscopic sinus surgery failure: a role for radical surgery?

OBJECTIVES: Endoscopic sinus surgery (ESS) is considered to be the golden standard for surgery in patients with chronic rhinosinusitis and nasal polyposis. However, there is still a small group of patients unresponsive despite repetitive surgery. Radical surgery aimed at reduction of the inflammatory burden and optimization of drainage of the sinuses has been suggested as a last resort for these patients. STUDY DESIGN: A prospective, questionnaire-based study was conducted in a group of 23 patients who underwent Denker's procedure for refractory chronic rhinosinusitis. Symptoms were evaluated before Denker's procedure and 12 months and 2 years after surgery. RESULTS: Patients reported improvement of feelings of congestion in 74%, rhinorrhea in 70%, and nasal obstruction in 60% of the cases. The following postoperative improvements were statistically significant: rhinorrhea (P = 0.001), feelings of congestion (P = 0.02), and nasal obstruction (P = 0.03). Reduced olfactory perception and asthma did not improve. CONCLUSION: Radical surgery may be a viable treatment option in case of recurrent ESS failure. EBM RATING: C-4.

Adult↗

PubMed1998

Y chromosome, urinary chemosignals, and an agonistic behavior (offense) of mice.

In mice, offense is one type of agonistic behavior associated with attacks. Offense of male mice was measured in a panel of testers design. The mice were DBA1 (D1) and DBA1.C57BL10-Y (D1.B10-Y). These are congenic for the male-specific, nonrecombining part of the Y chromosome. For the behavioral experiments, urine from D1 or D1.B10-Y mice was daubed on gonadectomized opponents. The opponents were of two genotypes, D1 or D1.B10-Y. The experimental subjects were of the same two genotypes. There were main effects for strain of experimental subject and strain of urine donor as well as interactions for strain of experimental subject x strain of gonadectomized opponent, strain of gonadectomized opponent x strain of urine donor, and strain of experimental subject x strain of gonadectomized opponent x strain of urine donor. These findings are consistent with a model in which this part of the Y chromosome affects testosterone-dependent pheromones and non-testosterone-dependent odor types acting as motivating stimuli, the olfactory perception of motivating stimuli for offense, and the motivational mechanism for offense.

Agonistic Behavior↗

PubMed1998

Human electroencephalographic (EEG) response to olfactory stimulation: two experiments using the aroma of food.

The present studies sought to examine the effect of olfactory stimulation on human Central Nervous System activity. In the first experiment (n = 21), EEG response to the 'synthetic' odours of chocolate, spearmint, almond, strawberry, vegetable, garlic and onion, and cumin or no odour was recorded from 19 electrodes (F3, F4, F7, F8, Fz, T3, T4, T5, T6, P3, P4, Pz, O1, O2, C3, C4, Cz) in all EEG frequencies (delta, theta, alpha, beta1 and beta2). Exposure to the odour of chocolate was associated with significant reductions in theta activity when compared with the odours of almond and cumin, with a trend towards significance when compared with no-odour control. Exposure to the odour of spearmint was associated with a significant reduction in EEG theta when compared with the no-odour control. No significant effects were observed in other frequencies. In a second experiment (n = 15), EEG response to the odours of real foods (chocolate, baked beans, rotting pork) and two controls (no odour and hot water) was recorded as in Experiment 1. The odour of chocolate was associated with significantly less theta activity than was any other stimulus. It is hypothesised that the alterations in theta reflect shifts in attention or cognitive load during olfactory perception, with a reduction in theta indicating a reduced level of attention.

Adolescent↗

PubMed1997

Odorant evoked magnetic fields in humans.

We investigated the olfactory evoked magnetic fields (OEFs) in 14 normal subjects. Pulses of odorant air containing amyl acetate or phenethyl alcohol, and odorless air were administered to the subject through a nasal tube. A clear and consistent OEF component, 1M, was identified in all subjects, and a second component, 2M, was detected in seven subjects, but no consistent component was identified in response to the odorless air. The peak latencies of the 1M and 2M components were approximately 320 and 630 ms, respectively. The waveforms produced by the odorless air were subtracted from the waveforms produced by the odorant air to obtain the 'subtraction' waveform, which indicated the 1M and 2M component more clearly. Their equivalent current dipoles (ECDs) were estimated in the regions around the Sylvian fissure symmetrically in both hemispheres. Therefore, these areas are proposed to be involved in olfactory perception in humans.

Adult↗

PubMed2001

Acute and chronic exposure to ammonia and olfactory acuity for n-butanol in the pig.

An associative learning method (using a food reward) was developed to measure pigs' olfactory acuity for n-butanol, a standard odourant in human olfactometry. The pig could press two operant paddles but it only received a food reward when it pressed the one over which n-butanol was released. Once each pig had reached a training criterion (10 consecutive roots on the correct paddle on each of two consecutive sessions) this method was used to assess the impact of acute and chronic exposure to an atmosphere containing approximately 40 parts per million (ppm) ammonia gas, compared to fresh air, on its ability to perceive different concentrations of n-butanol. These were presented using a staircase pattern, i.e. if the pig gained or failed to gain a food reward on two consecutive occasions the concentration was reduced or increased, respectively. Acute exposure for approximately 45min to about 40ppm ammonia had no effect (P>0.05) on the lowest detected concentration (LDC) of n-butanol in six pigs. The geometric mean LDC was 1.23 parts per trillion (ppt) in approximately 40ppm ammonia and 2.09ppt in fresh air. The LDC of three pigs increased, i.e. acuity fell, from 5.1 to 175.5ppt over 24 days of exposure to congruent with40ppm ammonia. Ammonia had no effect on one of the other pigs and the high variability in the LDC for the remaining two pigs produced no meaningful assessment of its impact. Subsequent removal to fresh air for a further 24 days led to partial recovery of acuity in one of the three pigs that had shown evidence of olfactory impairment but not in the other two. Collectively our findings suggest that chronic, but not acute, exposure to congruent with40ppm ammonia can interfere with olfactory perception in some pigs (50% of our sample) and that this loss of acuity is not necessarily reversible.

Journal Article↗