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At least 235 records · Page 13Linked to original sources
PubMed2002

Smelling home: a good solution for burrow-finding in nocturnal petrels?

Many burrowing petrels are able to return to their nests in complete darkness. The well-developed anatomy of their olfactory system and the attraction that food-related odour cues have for some petrel species suggest that olfaction may be used to recognize the burrow. In contrast, surface-nesting petrels may rely on visual cues to recognise their nest. We performed experiments on nine species of petrel (with different nesting habits) rendered anosmic either by plugging the nostrils or by injecting zinc sulphate onto the nasal epithelium. Compared with shamtreated control birds, we found that anosmia impaired nest recognition only in species that nest in burrows and that return home in darkness. Therefore, petrels showing nocturnal activity on land may rely on their sense of smell to find their burrows, while petrels showing diurnal activity or surface nesters may disregard olfactory cues in favour of visual guidance.

Animals↗
PubMed1984

University of Pennsylvania Smell Identification Test: a rapid quantitative olfactory function test for the clinic.

Despite the fact that clinical otolaryngologists are often presented with complaints of olfactory dysfunction, they have limited means to diagnose these problems. A major reason has been the lack of a clinically-useful and reliable quantitative test of olfactory function. Recent work at our Clinical Research Center has resulted in the development of such a test. This test--the University of Pennsylvania Smell Identification Test (UPSIT)--can be self-administered and uses microencapsulated odorants which are released by scratching standardized odor-impregnated test booklets. As indicated in this paper, studies have demonstrated that the UPSIT can identify most malingerers and is sensitive to age, gender, smoking habits, and a wide variety of olfactory disorders. A description of this new test, along with some of its applications, is presented.

Humans↗
PubMed1994

Drug-induced taste and smell disorders. Incidence, mechanisms and management related primarily to treatment of sensory receptor dysfunction.

Drugs in every major pharmacological category can impair both taste and smell function and do so more commonly than presently appreciated. Impairment usually affects sensory function at a molecular level, causing 2 major behavioural changes--loss of acuity (i.e. hypogeusia and hyposmia) and/or distortion of function (i.e. dysgeusia and dysosmia). These changes can impair appetite, food intake, cause significant lifestyle changes and may require discontinuation of drug administration. Loss of acuity occurs primarily by drug inactivation of receptor function through inhibition of tastant/odorant receptor: (i) binding; (ii) Gs protein function; (iii) inositol trisphosphate function; (iv) channel (Ca++,Na++) activity; (v) other receptor inhibiting effects; or (vi) some combination of these effects. Distortions occur primarily by a drug inducing abnormal persistence of receptor activity (i.e. normal receptor inactivation does not occur) or through failure to activate: (i) various receptor kinases; (ii) Gi protein function; (iii) cytochrome P450 enzymes; or other effects which usually (iv) turn off receptor function; (v) inactivate tastant/odorant receptor binding; or (vi) some combination of these effects. Termination of drug therapy is commonly associated with termination of taste/smell dysfunction, but occasionally effects persist and require specific therapy to alleviate symptoms. Treatment primarily requires restoration of normal sensory receptor growth, development and/or function. Treatment which restores sensory acuity requires correction of steps initiating receptor and other pathology and includes zinc, theophylline, magnesium and fluoride. Treatment which inhibits sensory distortions requires reactivation of biochemical inhibition at the receptor or inactivation of inappropriate stimulus receptor binding and/or correction of other steps initiating pathology including dopaminergic antagonists, gamma-aminobutyric acid (GABA)-ergic agonists, calcium channel blockers and some orally active local anaesthetic, antiarrhythmic drugs.

Anti-Infective Agents↗
PubMed2000

Behavioral lateralization during spontaneous smelling tasks.

The smelling behavior of 52 right-handed subjects was videotaped during tasks involving identification and recognition of different odors. Analysis showed that men more often used the right nostril than the left whatever the odor. There was no significant difference for the women. These results support a more marked cerebral asymmetry in men than in women and a main involvement of the right cerebral hemisphere in the olfactory processes at least by right-handed men.

Adult↗
PubMed2002

Phantom smelling.

A case of phantom smelling (phantosmia) is described in a 28-yr.-old man who developed permanent bilateral anosmia after a serious injury to olfaction-related brain structures at the age of 25 years. The findings indicate that, even years after loss of input from olfactory receptors, the neural representation of olfactory perception can still recreate olfactory sensations without any conscious recall of them. This indicates that the neural representation of olfactory sensations remains functional and implies that neuronal activity in the olfactory organ or in other brain structures gives rise to olfactory experiences perceived as originating from the perception of original odor substances. The report suggests the intriguing possibility that the olfactory perception is not a passive process that merely reflects its normal input from the olfactory system but is continuously generated by a neural representation in the olfactory organ or in other olfaction-related brain structures, based on both genetic and sensory determinants. To the author's knowledge this is the first reported case of its kind.

Adult↗
PubMed1998

Smell and taste of chewing gum affect frequency domain EEG source localizations.

We investigated brain electric field signatures of subjective feelings after chewing regular gum or gum base without flavor. 19-channel eyes-closed EEG from 20 healthy males before and after 5 minutes of chewing the two gum types in random sequence was source modeled in the frequency domain using the FFT-Dipole-Approximation. 3-dimensional brain locations and strengths (Global Field Power, GFP) of the equivalent sources of five frequency bands were computed as changes from pre-chewing baseline. Gum types differed (ANOVA) in pre-post changes of source locations for the alpha-2 band (to anterior and right after regular gum, opposite after gum base) and beta-2 band (to anterior and inferior after regular gum, opposite after gum base), and of GFP for delta-theta, alpha-2 and beta-1 (regular gum: increase. gum base: decrease). Subjective feeling changed to more positive values after regular gum than gum base (ANOVA).--Thus, chewing gum with and without taste-smell activates different brain neuronal populations.

Adult↗
PubMed1993

Smell and taste function in the visually impaired.

Surprisingly few quantitative studies have addressed the question of whether visually impaired individuals evidence, perhaps in compensation for their loss of vision, increased acuteness in their other senses. In this experiment we sought to determine whether blind subjects outperform sighted subjects on a number of basic tests of chemosensory function. Over 50 blind and 75 sighted subjects were administered the following olfactory and gustatory tests: the University of Pennsylvania Smell Identification Test (UPSIT); a 16-item odor discrimination test; and a suprathreshold taste test in which measures of taste-quality identification and ratings of the perceived intensity and pleasantness of sucrose, citric acid, sodium chloride, and caffeine were obtained. In addition, 39 blind subjects and 77 sighted subjects were administered a single staircase phenyl ethyl alcohol (PEA) odor detection threshold test. Twenty-three of the sighted subjects were employed by the Philadelphia Water Department and trained to serve on its water quality evaluation panel. The primary findings of the study were that (a) the blind subjects did not outperform sighted subjects on any test of chemosensory function and (b) the trained subjects significantly outperformed the other two groups on the odor detection, odor discrimination, and taste identification tests, and nearly outperformed the blind subjects on the UPSIT. The citric acid concentrations received larger pleasantness ratings from the trained panel members than from the blind subjects, whose ratings did not differ significantly from those of the untrained sighted subjects. Overall, the data imply that blindness, per se, has little influence on chemosensory function and add further support to the notion that specialized training enhances performance on a number of chemosensory tasks.

Blindness↗
PubMed1992

[Clinical application of the smell identification test].

Clinical application of the standardized "scratch and sniff" olfactory test in Japanese is described. Over 300 subjects participated in three experiments. In experiment 1, 29 odorants used in the smell identification test were rated as to their experiences. The ratios of the experiences in each combination of odorants were compared. In experiment 2, the test was applied to normal subjects. Average test scores decreased as a function of age, with the greatest decline occurring between the sixth and tenth decades of life. In experiment 3, the test was shown to differentiate between subjects with olfactory disorders and normal controls. This self-administered test now makes it possible to rapidly and accurately assess general olfactory function in the laboratory, clinic, or through the mail without complex equipment or space consuming stores of chemicals.

Adult↗
PubMedDate not supplied

An opioid receptor antagonist, naltrexone, does not alter taste and smell responses in humans.

Several studies have shown that an opioid receptor antagonist, naltrexone, decreases palatable food consumption. Naltrexone has also been reported to reduce ethanol intake in alcohol-preferring rodents and human alcoholics. The aim of the present study was to assess the effects of naltrexone on taste and smell responses in healthy male volunteers. Naltrexone did not alter intensity and pleasantness of sucrose, quinine, citric acid, sodium chloride, and ethanol taste. Similarly, ratings of olfactory stimuli (orange extract and ethanol) and Coca-Cola flavor were not influenced by the opioid antagonist. Our findings may indicate that: (i) naltrexone exerts marginal, if any, effects on gustatory and olfactory responses in humans; (ii) the drug does not alter orosensory responses to ethanol.

Adult↗
PubMed2002

The quinoxaline derivative caroverine in the treatment of sensorineural smell disorders: a proof-of-concept study.

The treatment of non-conductive olfactory disorders is to a large extent an unsolved problem. This proof-of-concept study focused on possible effects of the N-methyl-D-aspartate (NMDA) antagonist caroverine. Potential mechanisms for the hypothesized effect included reduced feedback inhibition in the olfactory bulb as a consequence of NMDA antagonistic actions and antagonism of an excitotoxic action of glutamate. A total of 77 consecutive patients with non-conductive olfactory disorders were included in the study. Fifty-one patients received caroverine for 4 weeks (120 mg/day); 26 controls matched for age, gender and duration of olfactory loss were treated with zinc sulfate for the same length of time (400 mg/day). Olfactory sensitivity was evaluated before and after treatment. Testing included assessment of n-butanol odor threshold and odor identification. When compared to baseline, treatment with caroverine improved both odor thresholds (p = 0.005) and odor identification (p = 0.042) in anosmic patients. In hyposmic patients it significantly improved odor identification ability (p = 0.041). In contrast, zinc sulfate had no significant effect on olfactory function. These results indicate that caroverine appears to be effective for the treatment of non-conductive smell disorders.

Adolescent↗
PubMed1992

Taste and smell.

Olfaction declines dramatically with age. Taste is relatively robust. A variety of causes other than aging are known to produce declines in olfaction and to a lesser extent in taste. Many chemosensory deficits in the elderly cannot be attributed to age but rather to pathologic conditions. In addition to deficits, individuals may experience taste or smell phantoms. In many cases, losses and phantoms are untreatable but their effects on the elderly may be mitigated by appropriate coping skills.

Aged↗
PubMed2004

[The application of functional magnetic resonance imaging for the assessment of localisation and activation of cortex smell centers depending on stimulus used in normal volunteers].

PURPOSE: To determine the location and activation of brain smell centres in response to olfactory nerve-mediated and combined olfactory and trigeminal nerve-mediated stimulation using functional MRI. SUBJECTS AND METHODS: MRI brain scans were performed in 10 healthy volunteers, aged 22-36 years, right handed, non-smokers, without any CNS diseases, not taking any medication to determine and compare the activated cortex regions during stimulation by patchouli and geraniol. fMRI was performed on Siemens Magnetom Vision 1,5 T imager with a head-neck coil using SE and EPI sequences. Functional MR imaging studies were obteined in the same plane as T11 eighted images in an axial plane by using echo planar imaging. In each of 14 contiguous planes parallel to anterior-posterior commisure line images that depicted blood-oxygen-level-dependent (BOLD) effect were acquired. The subject inhaled odorized air through both nares for 30 seconds. During 30-second off period the subject received room air at the same flow rate. For each of activated cortical zones the number of pixels activated was calculated. Image reconstruction and analysis were performed using standard imager software installed in MR imager. RESULTS: The exposure to the olfactory and trigeminal nerve-mediated stimuli showed more activated regions than to the olfactory nerve-mediated stimuli. Geraniol evoked the biggest activation in orbitofrontal region, cingulate gyrus and insula. Patchouli activated orbitofrontal cortex, insula, parahippocampal gyrus, occipital cortex, and corpus callosum. CONCLUSIONS: The results of present study confirm the ability to localize patterns of cortical activity with fMRI during olfactory tasks.

Adult↗
PubMed1990

Identification of alcohol by smell among preschoolers: evidence for early socialization about drugs occurring in the home.

This study tested preschoolers' ability to provide accurate verbal associations to alcoholic beverage odors and whether this ability was related to parental drinking patterns and motivations. Older preschoolers performed better than younger preschoolers; photographic cues improved performance; children who correctly identified a substance by smell had socially appropriate knowledge of the culturally appropriate users of the substance; children reported liking substances that are used mainly by children and adults, and generally reported disliking substances whose use is legally limited to adults only; children were better at identifying substances they commonly use, but success at recognition of alcoholic beverages was related to heavier parental drinking and use of alcohol for escape reasons. Findings have implications for theories of socialization to drug use and for models of prevention.

Alcohol Drinking↗
PubMed1989

Clinical characteristics of taste and smell disorders.

Chemosensory problems can have major consequences for those patients who develop them. Although more than 200 conditions and 40 medications have been linked to taste and smell disorders, for most patients the cause will fall into one of the following categories: nasal/sinus disease, idiopathic, postviral URI, and head trauma. Careful attention to clinical characteristics will aid immensely in the diagnosis. Parosmias, dysgeusias and the burning mouth syndrome are symptoms that deserve special consideration.

Chemoreceptor Cells↗
PubMed1989

Medical management of taste and smell disorders.

Chemosensory dysfunction is most often secondary to one of only a few causes: nasal/sinus disease, viral infection, toxic chemical exposure, head trauma, as well as medication-related and idiopathic conditions. Medication-related disorders are corrected by discontinuance of the causative medicine. Our experiences have also shown that only dysfunctions of smell caused by disorders of the nose and/or sinuses are amendable to therapy.

Adrenal Cortex Hormones↗
PubMed1989

Neurologic evaluation of taste and smell disorders.

Specific neurologic causes of chemosensory deficits are uncommon. A careful history and neurologic examination and the use of appropriate neurodiagnostic studies will identify the underlying cause in many cases and allow for appropriate management. The neurologic evaluation of the patient with abnormalities of smell, taste, or both is reviewed with specific reference to the disorders of the central and peripheral nervous system that may be causative.

Humans↗
PubMed1987

[Classification and definition of smell and taste disorders].

The smell and taste disorders are defined in terms due to two principles - the type and site of lesion. The quantitative dysosmias (anosmia, hyposmia, hyperosmia) correspond to the quantitative dysgeusias (ageusia, hypogeusia, hypergeusia) and the qualitative dysosmias (parosmia, pseudo-osmia, phantosmia, agnosmia) correspond to the qualitative dysgeusias (parageusia, pseudogeusia, phantogeusia, agnogeusia). Due to the site of lesion we can differentiate between respiratory, epithelial, combined, neural, and central dysosmias as well as epithelial, neural, and central dysgeusias. Typical examples are demonstrated, denying other classifications and terms as not precisely enough or negligible ones.

Ageusia↗