Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Taste Threshold”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,225 records · Page 68Linked to original sources
PubMed2001

Shifting gustatory thresholds and food cravings during pregnancy as expanding uterine-induced steady potential shifts within the insula: an hypothesis.

A logical extrapolation from the principle that structure dictates function is that transient or anomalous experiences are consequences of simultaneous stimulations of proximal brain regions not typically co-activated. In this paper the occasional shifts in gustatory threshold during the menstrual cycle, the craving for unusual tastes experienced by some during pregnancies, and, the reports by postmenopausal women of the "burning mouth syndrome" are hypothesized to be artifacts of the proximity of gustatory and uterine representations within the female insula. Transient (menstrual) or tonic (pregnancy) stimulation within the uterus might shift the locus of neuronal activity within the insula to include adjacent gustatory neurons and consequently alter taste experiences. Specific tests of this hypothesis are suggested.

Adult↗
PubMed1994

Ipsi- and bilateral interactions in taste.

In two experiments, the integration over spatial extent in taste was investigated for threshold sensitivity to NaCl and for suprathreshold intensity perception of saltiness. The area of stimulation was doubled by adding either an ipsilateral or a bilateral stimulus. The two stimuli could be of equal or unequal intensity. The data showed that at threshold level a probability summation model applied to all bilateral and most of the ipsilateral stimulus combinations. Probability summation failed to predict detection probability when two stimuli with different intensities were presented at the same tongue side. For suprathreshold stimuli, the magnitude of the saltiness sensation as estimated by a line-length method depended on the level of stimulation. The possible peripheral interaction mechanisms and central factors contributing to the taste response were discussed.

Adult↗
PubMedDate not supplied

[Setting a maximum allowable concentration for urea in reclaimed potable water and evaluating the nature of its biological action].

The purpose of the study was to identify maxim allowable concentrations of urea in reclaimed potable water. The urea concentration equal to 80 mg/l is the threshold dose influencing the taste and flavor of water. Urea is a low toxicity substance (LD50 = 14,300 mg/kg), the effect of which is not cumulative. However, when used in high doses it affects bioenergetic and cholinergic processes and causes changes in ECG, higher nervous activity and visceral structure. It has been shown that when applied to warm-blooded animals the acting dose of urea is 14.3 and 1.43 mg/kg (1/1000 and 1/10000 LD50), the threshold dose is 0.72 mg/kg (1/20000 LD50), and the ineffective dose is 0.36 mg/kg (1/40000 LD50) which amounts to the concentration of 10 mg/l. In terms of toxic effects the dose equal to 10 mg/l is taken to be the maximally allowable concentration of urea. It is recommended to use the Laham biotest for measuring urea in water.

Animals↗
PubMedDate not supplied

Clinical evaluation of taste dysfunction using a salt-impregnated taste strip.

We have used special tests to investigate taste function in detail. To evaluate acuity for a salty taste, we used a paper with salt crystals, Salsave. The procedure is simple and takes only a few minutes. We analyzed the relationships between the magnitude of the threshold of response to this test and the results of other taste function tests in 126 patients who visited our clinic. The mean magnitude of the response to Salsave significantly correlated with the results of other taste tests. Thus, this is a useful method for screening the detection and recognition threshold of a salty taste.

Adult↗
PubMed1997

Taste- and odor-reactivity in heroin addicts.

Opiates in general, and heroin in particular, are known to induce compulsive drug-seeking and drug-taking behavior. Addiction is accompanied by psychobiological processes which may distort perception of sensory stimuli. Gustatory and olfactory stimuli are hedonically polarized and therefore most appropriate for the assessment of the organism's reactivity to "useful" and "harmful" chemosensory events. Previous studies revealed that psychophysical self-estimates and reflectory facial expressions mirror with comparable reliability the hedonics of the perceived taste and odor sensations. In the present study both cognitive verbal and reflectory facial expressions of a group of: a) heroin addicts were recorded and compared to those of a group of b) detoxified former addicts and to c) a group of matching controls. Results show that all three groups differentiate between pleasant, indifferent and aversive tastes and odors. Active addicts estimated sweet taste and savory smells as being somewhat more pleasant, and bitter and sour tastes and a putrid odor as less unpleasant than did the other two groups. The reflectory facial displays of addicts were less expressive and discriminative than those of the two other groups. Taste- and odor-induced facial displays are known to be controlled primarily by the brainstem. The findings indicate that heroin-addiction affects brain-mechanisms, which mirror taste- and odor-hedonics. Modulation of the phylogenetically ancient, sensory-motor coordinations was found to be of a different pattern than that of the cortically-controlled cognitive reactions.

Adult↗
PubMed1982

Long-term effects of radiotherapy on taste and salivary function in man.

The long-term effects of radiotherapy on taste and salivary function were studied in 13 patients treated by radiation 1--7 years previously for tumors of the head and neck. Taste function was quantitatively evaluated using a standard forced choice, three-stimulus-drop technique for the determination of detection and recognition thresholds and a forced-scaling technique for the determination of taste intensity responsiveness. Parotid salivary function was quantitatively evaluated by determination of flow rate and protein secretion rate. Nine of the 13 patients studied (69%) had measurable taste loss; every patient who had radiotherapy including the parotid glands had measurable salivary dysfunction. Our results demonstrate that curative courses of radiotherapy for tumours of the head and neck may result in long-term changes in taste and salivary function. From the present study, the maximum tolerance doses resulting in a 50% complication rate 5 years after treatment (TD 50/5) are estimated to be 40--65 Gy for xerostomia and 50--65 Gy for taste loss. Therefore, in a standard treatment regimen for tumors of the head and neck, with curative intent, gustatory and salivary gland tissues frequently sustain maximum tolerance injury.

Follow-Up Studies↗
PubMed1975

[Where lies the boundary between common sensation and taste perception in electrogustometry (author's transl)].

The shift of the electrogustatory threshold following section of the corda tympani has been investigated in 14 patients. Postoperatively the anterior half of the tongue showed complete ageusia. Two thirds of the patients were able to recognize stimulations of 50-127 muA as a burning, and not a sour metallic, sensation for at least 1-2 weeks. Probably the trigeminal nerve endings perceive this burning sensation during the period of taste bud degeneration. A similar situation exists in cases where the gustatory fibres are interrupted proximal to the gustatory ganglion, because the tasts buds do not degenerate. It is therefore important to ask the patient to describe the sensation experienced. Only a sour metallic taste during electrogustometry should be regarded as a true gustatory sensation.

Adult↗
PubMed1989

A theoretical model for perceived intensity in human taste and smell. II. Temporal integration and reaction times.

The theoretical model for perceived intensity in human taste and smell published previously was extended by incorporating the concept of signal detectability and temporal integration phenomena at low and high stimulus levels. The processes involved in human taste and smell perception are divided into three stages: a) An "internal meter" registers outside signals. Adaptation occurs at this stage. b) The meter is read for two possible purposes: to detect a weak signal or to estimate the signal's intensity. Both tasks require the smoothing of noise, which is accomplished by integration of the meter over time. c) The internal estimate is expressed through the use of a scaling method.

Humans↗
PubMed2006

Taste in dementing diseases and parkinsonism.

Like with many sensory abilities a reduction of taste and smell occurs during aging. Since there are hints to an additional reduction in dementing diseases, we assessed 52 patients, 26 women and 26 men, who were presented to a memory clinic, using the Sniffin' Sticks, Whole Mouth and Taste Strip Tests. While smoking, alcohol consumption, intake of drugs and sex exerted only minor impact, age and the severity of cognitive impairment were of major importance. There was a moderate but significant correlation between the severity of dementia, taste and smell, even if the age effect was partialled out. Notably, patients with Parkinson syndrome showed worse taste and smell abilities than those without. Here the differences were indeed marked enough to play a possible role in making the diagnosis. This exploratory study confirms a mild reduction of gustatory function in dementing diseases over and beyond that of normal aging which--in addition to a reduction of smell--seems to be especially marked in Parkinson syndromes.

Adult↗
PubMed1994

Odor-cued taste avoidance: a simple and efficient method for assessing olfactory detection, discrimination and memory in the rat.

Rats quickly learn to avoid licking at a drinking tube containing an odorant and quinine hydrochloride. After training, the rat responds readily to water but sniffs at but does not lick a tube containing a solution of isoamyl acetate. Learning occurs after only one or two exposures to the combination of odor and tastant. This method can be used to demonstrate odor discrimination, odor memory, and to assess detection of low concentrations of odors.

Animals↗
PubMed1987

Age-related olfactory and taste changes and interrelationships between taste and nutrition.

This article critically reviews the literature on age-related olfactory and taste changes and the interrelationships between nutrition and taste. Age-related taste alterations are controversial, but there is consensus on an olfactory decline with age. Much of the age-related chemoreceptive research has used inappropriate methodology, thus leaving many findings inconclusive. Changes in the taste system with age may be related to nutrient intake, which in turn can be influenced by taste. Literature on such interrelationships is limited. Vitamins A, thiamin, B-6, B-12, folacin, zinc, and copper are thought to influence taste function. Moreover, those nutrients are of concern in the aged. The use of appropriate methodology is critical not only for the sensory but also for the nutritional aspects, particularly for qualitative and quantitative assessments of nutrient intakes. This review considers the experimental deficiencies (small sample size, inappropriate age range, inadequate psychophysical and stimuli presentation procedures, and poor dietary intake assessment) of studies reported in the literature and suggests major needs for research.

Aging↗
PubMedDate not supplied

Taste aversions to several halogenated hydrocarbons.

Five halogenated hydrocarbons (chloral; trichloroethylene; 1,2-dichloroethylene; 1,2-dichloroethane and 1,1,2-trichloroethane) were evaluated in the taste aversion paradigm to determine thresholds for producing aversion effects. Comparisons were made between threshold determination for acute and repetitive conditioning trials. All of the compounds produced saccharin aversions following one pairing of the chemical exposure with saccharin ingestion. Repetitive conditioning trials did not alter the thresholds for producing aversions with any of the five compounds evaluated. Potencies of the compounds in producing conditioned taste aversions were chloral greater than 1,1,2-trichloroethane greater than 1,2-dichloroethane greater than 1,2-dichloroethylene greater than trichloroethylene.

Animals↗
PubMed1990

Taste perceptions and hedonics in eating disorders.

Hedonic and intensity ratings of 20 dairy solutions, with varying levels of fat and sucrose, were obtained before and after treatment for anorectic-restrictors, anorectic-bulimics, normal-weight bulimics, and control subjects. There were no differences between diagnostic groups in ability to rate sweetness intensity; all subjects were able to correctly assess increasing sucrose concentration. During the pretreatment test, both bulimic groups showed elevated intensity ratings of lower fat solutions and solutions which contained no sugar as compared with the other two groups. These differences were not present after treatment. There were differences in hedonic ratings between the anorectic groups and the controls, which persisted even after treatment. Both groups of patients showed an aversion to high fat solutions; anorectic-restrictors also demonstrated an aversion to all solutions which contained no sugar. The stability of these hedonic profiles suggests that these responses may be trait characteristics of anorexia nervosa.

Adolescent↗
PubMed1992

Ibotenic acid lesion of the hypothalamic paraventricular nucleus produces weight gain but modifies neither preference nor aversion for saccharin.

We showed recently that bilateral ibotenic acid lesions of the lateral hypothalamus (LH) produced three main behavioral disturbances in the rat, i.e., an increase in the gustatory preference and aversion thresholds for saccharin, permanent body weight and water intake deficits, and an alteration of morphine-induced modulation of taste. The two first results could suggest that the modification of the gustatory thresholds and the ingestive deficits are closely interrelated. Given this situation, we hypothesized that, conversely, a brain lesion known to induce obesity and hyperdipsia would therefore decrease the gustatory preference and aversion thresholds for saccharin. In order to test this hypothesis we analyzed the effects of the bilateral lesion of the hypothalamic paraventricular nucleus (PVH) by injection of ibotenic acid (2 micrograms in each side) on saccharin preference. The main results are as follows: 1) The neurotoxin selectively destroyed parvicellular neurons while the magnocellular cells were spared. 2) In comparison to the normal daily gain in body weight of the sham-lesioned animals, the lesioned rats showed an enhanced weight gain that became significant from the third day after the surgery up until the day of sacrifice, 37 days later. 3) In contrast to electrolytic lesions of the PVH, the ibotenic acid lesions of this nucleus did not induce hyperdipsia. 4) Preference and aversion thresholds for saccharin were not significantly modified by the lesion. 5) Whereas low doses of morphine suppressed the preference for saccharin in sham-lesioned rats when the concentration of the sweetener solution was at the threshold value, this suppressive effect was not observed in PVH-lesioned rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Smell and other sensory disturbances in migraine.

Osmophobia or hyperosmia featured in 25 of 50 migraineurs during the headache phase of their attacks. Pleasant or unpleasant odours could precipitate migraines in 11 patients in this series. Other sensory disturbances and precipitants were also studied. Neurological precipitation of attacks provides further support for a primary neural rather than a vascular pathogenesis of migraine.

Adolescent↗
PubMed1992

Hormonal milieu affects tailflick latency in female rats and may be attenuated by access to sucrose.

The steroid hormones estrogen (E) and progesterone (P) are known to modify pain sensitivity; however, the relative role of each of these hormones in this process is not well understood. To systematically investigate the effects of E and P on nociception, pain sensitivity was assessed under several hormone conditions. Tailflick (TF) latencies were measured every other day in 10 cycling female rats and 10 female rats during luteal functioning (pseudopregnancy). Thirty ovariectomized (OVX) rats were tested for TF latency following administration of 10 micrograms estradiol benzoate (EB) and either 0.0, 0.5, or 1.0 mg of P. Significant differences in TF latency were seen across days of the estrous cycle but not during luteal functioning. Tailflick latencies during luteal functioning were elevated relative to latencies in normally cycling animals. Among OVX rats, those administered EB and P (1.0 mg) displayed significant reductions in TF latency compared to vehicle controls. As a separate line of research indicated that consumption of highly palatable foods modified pain sensitivity, whether chronic sucrose consumption might overide the influence of hormones on nociception was examined. Ovariectomized rats given EB and P (0.0, 0.5, or 1.0 mg) were allowed chronic exposure to a 32% sucrose solution. Our preliminary findings suggest that chronic sucrose consumption attenuates hormonally induced differences in nociception.

Animals↗
PubMedDate not supplied

Odor sensitivity is impaired in HIV-positive cognitively impaired patients.

An estimated 7-28% of patients infected by the human immunodeficiency virus (HIV) develop dementia and at least 50% develop mild neurocognitive impairment. Past studies have shown odor identification impairments in HIV + neurocognitively impaired patients. It is difficult, however, based on an odor identification test to state with certainty that individuals with cognitive impairment have sensory olfactory deficits, because odor identification tests are known to draw upon cognitive skills. In the present study odor detection sensitivity was evaluated using an ascending, forced-choice, two-alternative, odor threshold test for butanol. Subjects were divided into three groups, HIV seropositive (HIV+) neurocognitively impaired, HIV+ neurocognitively unimpaired, and HIV negative, based on neurological and psychological testing. An analysis of variance revealed significantly poorer odor sensitivity for the HIV+ neurocognitively impaired group than for the two control groups. A significant negative correlation between degree of cognitive impairment and olfactory sensitivity was also found. We suspect that the olfactory deficits found in the HIV+ neurocognitively impaired subjects are primarily due to damage to the central nervous system; however, nasal infection may be a contributing etiology.

AIDS Dementia Complex↗