Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Taste modeling”

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 1,009 records · Page 56Linked to original sources
PubMedDate not supplied

Functional MRI of congenital hyposmia: brain activation to odors and imagination of odors and tastes.

PURPOSE: Our goal was to use functional MRI (fMRI) to define brain activation in response to odors and imagination ("memory") of odors and tastes in patients who never recognized odors (congenital hyposmia). METHOD: Functional MR brain scans were obtained in nine patients with congenital hyposmia using multislice echo planar imaging (EPI) in response to odors of amyl acetate, menthone, and pyridine and to imagination ("memory") of banana and peppermint odors and to salt and sweet tastes. Functional MR brain scans were compared with those in normal subjects and patients with acquired hyposmia. Activation images were derived using correlation analysis, and ratios of areas of brain activated to total and hemispheric brain areas were calculated. Total and hemispheric activated pixel counts were used to quantitate regional brain activation. RESULTS: Brain activation in response to odors was present in patients with congenital hyposmia. Activation was significantly lower than in normal subjects and patients with acquired hyposmia and did not demonstrate differential vapor pressure-dependent detection responsiveness or odor response lateralization. Regional activation localization was in anterior frontal and temporal cortex similar to that in normal subjects and patients with acquired hyposmia. Activation in response to presented odors was diverse, with a larger group exhibiting little or no activation with localization only in anterior frontal and temporal cortex and a smaller group exhibiting greater activation with localization extending to more complex olfactory integration sites. "Memory" of odors and tastes elicited activation in the same central nervous system (CNS) regions in which activation in response to presented odors occurred, but responses were significantly lower than in normal subjects and patients with acquired hyposmia and did not lateralize. CONCLUSION: Odors induced CNS activation in patients with congenital hyposmia, which distinguishes olfaction from vision and audition since neither light nor acoustic stimuli induce CNS activation. Odor activation localized to anterior frontal and temporal cortex, consistent with the hypothesis that olfactory pathways are hard-wired into the CNS and that further pathways are undeveloped with primary olfactory system CNS connections but lack of secondary connections. However, some patients exhibited greater odor activation with response localization extending to cingulate and opercular cortex, indicating some olfactory signals impinge on and maintain secondary connections consistent with similar functions in vision and audition. Activation localization of taste "memory" to anterior frontal and temporal cortex is consistent with CNS plasticity and cross-modal CNS reorganization as described for vision and audition. Thus, there are differences and similarities between olfaction, vision, and audition, the differences dependent on unique qualities of olfaction, perhaps due to its diffuse, primitive, fundamental role in survival. Response heterogeneity to odors may reflect heterogeneous genetic abnormalities, independent of anatomic or hormonal changes but dependent on molecular abnormalities in growth factor function interfering with growth factor/stem cell interactions. Patients with congenital hyposmia offer an unique model system not previously explored in which congenital smell lack as measured by fMRI is reflective of congenital dysfunction of a major sensory system.

Adult↗
PubMed2003

Differential pattern of cAMP response element-binding protein activation in the rat brain after conditioned aversion as a function of the associative process engaged: taste versus context association.

Ample data indicate that cAMP-response element-binding protein (CREB) is essential for the formation of long-term memory in various species and learning systems. This implies that activated CREB could delineate neuronal circuits that subserve items in memory, while leaving open the possibility that the specifics of CREB activation itself contribute to the specificity of the internal representation encoded by the relevant circuit. We describe here the differential activation of CREB in the rat brain as a function of two related yet distinct forms of aversive conditioning: conditioned taste aversion (CTA) and conditioned context aversion (CCA). We found that CTA induces strong CREB activation in the insular cortex (IC) and the lateral septum (LS), but not in the parietal cortex (PC) and the medial septum (MS). In contrast, CCA results in strong activation in the PC and MS, but not in the IC and LS. These findings are congruent with a model that links differential pattern of activity within the LS and the MS with the acquisition of elemental versus contextual conditioning and, more generally, with the notion that CREB activation delineates learning-dependent circuits as a function of the type of cognitive process engaged.

Animals↗
PubMed1985

Taste responses to saltiness among hypertensive subjects under different therapeutic regimens.

Dietary sodium restriction is increasingly regarded as important in the prevention and treatment of essential hypertension. However, low-sodium diets are frequently considered unpalatable and therefore unfeasible. The objectives of this study were to determine (a) whether hypertensives, treated and untreated, differ in saltiness taste perception from age-matched normotensive controls and (b) whether sodium reduction can be accomplished by substituting another taste stimulus without reducing apparent saltiness and palatability. Subjects included 72 hypertensives, 44 to 69 years old, divided among three treatment groups; 25 age-matched normotensive controls; and an additional 21 normotensives, 20 to 43 years old, to provide an age continuum for evaluating age effects. Taste responses were measured in terms of saltiness intensity and preference using tomato juice varying systematically in sodium chloride and citric acid content. No significant differences were found between normotensives and hypertensives. No significant effects were associated with blood pressure status, therapeutic regimen, age, sex, race, or anthropometric measurements. Both sodium chloride and citric acid were main effects for saltiness, allowing a trade-off between salt and acid. Addition of citric acid permitted 50% reduction of sodium content in tomato juice without disturbing palatability criteria. Results provide a model for modifying other processed foods.

Adrenergic beta-Antagonists↗
PubMed1996

Gustatory evoked magnetic fields in humans.

Magnetic fields evoked by taste stimuli of the human tongue were measured over the whole head using a helmet-shaped 64 channel magnetoencephalography system in five normal subjects. The stimuli were 10% glucose and 0.3 M NaCl solutions and distilled water. The most prominent peak (N175m) appearing over the bilateral hemispheres had a latency of 150-210 ms. The N175m sources were located using a two-dipole model in a spherical conducting medium based on the individual head dimensions and superimposed on magnetic resonance images. The N175m dipoles due to 10% glucose and 0.3 M NaCl stimuli were located at the operculum and circum-insular areas in both hemispheres, but those due to distilled water could not be located accurately.

Adult↗
PubMed1991

Determination of disulfide array and subunit structure of taste-modifying protein, miraculin.

The taste-modifying protein, miraculin (Theerasilp, S. et al. (1989) J. Biol. Chem. 264, 6655-6659) has seven cysteine residues in a molecule composed of 191 amino acid residues. The formation of three intrachain disulfide bridges at Cys-47-Cys-92, Cys-148-Cys-159 and Cys-152-Cys-155 and one interchain disulfide bridge at Cys-138 was determined by amino acid sequencing and composition analysis of cystine-containing peptides isolated by HPLC. The presence of an interchain disulfide bridge was also supported by the fact that the cystine peptide containing Cys-138 showed a negative color test for the free sulfhydryl group and a positive test after reduction with dithiothreitol. The molecular mass of non-reduced miraculin (43 kDa) in sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) was nearly twice the calculated molecular mass based on the amino acid sequence and the carbohydrate content of reduced miraculin (25 kDa). The molecular mass of native miraculin determined by low-angle laser light scattering was 90 kDa. Application of a crude extract of miraculin to a Sephadex G-75 column indicated that the taste-modifying activity appears at 52 kDa. It was concluded that native miraculin in pure form is a tetramer of the 25 kDa-peptide and native miraculin in crude state or denatured, non-reduced miraculin in pure form is a dimer of the peptide. Both tetramer miraculin and native dimer miraculin in crude state had the taste-modifying activity.

Amino Acid Sequence↗
PubMed1990

Development of learned food aversions in humans: investigation in a "natural laboratory" of cancer chemotherapy.

Humans often develop learned food aversions (LFAs) to foods or beverages consumed in temporal contiguity to gastrointestinal distress. Viewed as a classical conditioning process, principles of LFA development have been studied in the animal laboratory. Cancer chemotherapy provides a "natural laboratory" for examining whether these principles characterize human LFA development. Chemotherapy patients (n = 63) were interviewed prior to a regularly scheduled chemotherapy infusion (i.e. target infusion). Foods and beverages consumed in the preceding 24 h were identified. Postinfusion nausea and vomiting (PNV) was assessed. Finally, preference changes for items consumed prior to the target infusion were assessed prior to patients' next chemotherapy infusion. Contrary to hypothesis, (a) less preferred and familiar items were not more likely to become LFA targets, (b) LFA items were not consumed in close temporal contiguity to either the initiation of chemotherapy or PNV, and (c) LFAs developed in the absence of PNV. Consistent with the hypothesis, the severity of PNV was associated with a greater likelihood of LFA development. Problems in defining LFAs under non-experimental conditions are discussed as are the implications of results for the classical conditioning model of human LFA development.

Aged↗
PubMedDate not supplied

Solution structures of 1:1 complexes of oxyphenonium bromide with beta- and gamma-cyclodextrins.

The solution structures of complexes of oxyphenonium bromide (OB) with beta- and gamma-cyclodextrins (beta- and gamma-CDs, respectively) in deuterium oxide have been investigated by 500 MHz proton NMR spectroscopy and molecular mechanics calculations. The chemical shifts induced by complex formation provide the 1:1 binding constants and the chemical shift variations, DeltadeltaOB-CD, with complexation for the protons of OB and the CDs. The observed binding constants are very close to those obtained by other methods and are in the following order: beta-CD > gamma-CD > alpha-CD. Initial structures of the complexes are constructed on the basis of the ROESY spectra and the DeltadeltaOB-CD values and are optimized by molecular mechanics calculations. The intermolecular distances between the protons of OB and CD calculated for these structures are well-correlated with the observed ROESY intensities. The cyclohexyl group of OB penetrates deeply into a beta-CD cavity, and the phenyl group is close to the wide rim of the cavity. The phenyl and cyclohexyl groups of OB are both incorporated into a gamma-CD cavity. Furthermore, these structures of the complexes are consistent with the suppression of bitter taste and basic hydrolysis of OB by CDs and the polarity of binding sites of OB.

Kinetics↗
PubMedDate not supplied

The controls of fat intake.

OBJECTIVE: To present evidence on the control of the size of fatty meals in the context of the result of interactions of orosensory positive-feedback and postingestive negative-feedback mechanisms activated by fat stimuli in rodent models of feeding and of obesity. METHOD: We examined the effects of orosensory stimuli and postingestive stimuli in Sprague-Dawley rats, and in the genetically obese Zucker (fa/fa) rat. We used the sham feeding rat preparation to isolate the orosensory stimulating and postingestive satiating properties of oils. The negative-feedback satiating properties of fats were elicited by intestinal infusions of fats. The Zucker rat is an animal model of obesity with abnormal control of meal size and increased intake of fats. Using this model we further examined the interaction of orosensory and postingestive stimuli in the control of meal size. RESULTS: The orosensory properties of fats are sufficient to drive sham feeding and are not dependent on the postabsorptive metabolic consequences of oils in normal and Zucker rats. The satiating action of fats must act at preabsorptive sites because reduction of intake occurs before absorption of fat. The satiating potency of fats is dependent upon their specific chemical conformation and is mediated by endogenous cholecystokinin and afferent fibers of the abdominal vagus. We have found that oils produce significantly more orosensory positive feedback in obese Zucker rats than in lean rats in experimental tests of preference. This is probably the major abnormal mechanism responsible for the increased preference for fats that is characteristic of obese rats because we have not identified any significant decrease in the postingestive satiating potency of fats in obese Zucker rats. CONCLUSIONS: Fat intake is controlled by both orosensory and postingestive stimuli in normal and genetically obese rodents. In the Zucker rat the investigation of this model of genetic obesity has produced data that is congruent with the preference for high fat foods in obese people and suggests further experiments directed toward a deeper understanding of the controls of fat intake and how they are disordered.

Animals↗
PubMed1985

Potentiation and overshadowing in preweanling and adult rats.

Four experiments compared the aversion acquired by 18-day-old and 60-day-old rats to a flavor that was either tasted alone or in combination, simultaneously or successively, with another flavor when paired with illness. The purpose was to study temporal variables and theoretical issues pertinent to potentiation and overshadowing while investigating ontogenetic differences in these phenomena. When either the preweanlings or the adults were presented a simultaneous compound flavor (sucrose/coffee) followed by lithium chloride-induced illness, greater sucrose aversions were found than for animals conditioned on sucrose alone--that is, potentiation. Preweanlings demonstrated greater potentiation than did adults, whether the conditioned stimulus-unconditioned stimulus (CS-US) delay was 0 or 1 hr. This potentiation was eliminated by nonreinforced presentations of the alternative CS element. Potentiation was not seen when the two flavors were presented successively as the CS; instead, overshadowing occurred. Tests of configuring by extinction procedures indicated a tendency for these animals to form a configured representation of the simultaneous compound solution. This disposition for configuring tended to be more pronounced for preweanlings than for adults. Ontogenetic differences in response to configuration, CS saliency, and generalization decrement seem consistent with at least one model of potentiation and the ontogenetic differences in potentiation seen in the present experiments.

Animals↗
PubMed2003

Genetic analysis of a complex trait in the Utah Genetic Reference Project: a major locus for PTC taste ability on chromosome 7q and a secondary locus on chromosome 16p.

The ability to taste phenylthiocarbamide (PTC) shows complex inheritance in humans. We obtained a quantitative measure of PTC tasting ability in 267 members of 26 large three-generation families that were part of a set of CEPH families that had been used for genetic mapping. Significant bimodality was found for the distribution of age and gender adjusted scores (P<0.001), with estimated means of 3.16 (SD=1.80) and 9.26 (SD=1.54). Using the extensive genotyping available in these families from the genetic mapping efforts, we performed a genome scan by using 1324 markers with an average spacing of 4 cM. Analyses were first carried out with a recessive genetic model that has traditionally been assumed for the trait, and a threshold score of 8.0 delineating tasters from non-tasters. In this qualitative analysis, the maximum genome-wide lod score was 4.74 at 246 cM on chromosome 7; 17 families showed segregation of the dichotomous PTC phenotype. No other lod scores were significant; the next highest score was on chromosome 10 (lod=1.64 at 85 cM), followed by chromosome 3 (lod=1.29 at 267 cM). Because PTC taste ability exhibited substantial quantitative variation, the quantitative trait was also analyzed by using a variance components approach in SOLAR. The maximum quantitative genome-wide lod score was 8.85 at 246 cM on chromosome 7. Evidence for other possible quantitative loci was found on chromosomes 1 (lod=2.31 at 344 cM) and 16 (lod=2.01 at 14 cM). A subsequent two-locus whole-genome scan conditional on the chromosome 7 quantitative trait locus identified the chromosome 16 locus (two-locus lod=3.33 at 14 cM).

Adolescent↗
PubMed2006

Factors affecting satisfaction level with the food services in a military hospital.

OBJECTIVE: To determine the factors affecting general satisfaction level of patients with the food services in a military hospital in Turkey. STUDY DESIGN: The study was carried out in a military hospital providing tertiary health care services with the capacity of 1000 hospital bed. A questionnaire was used as data collection tool on measuring satisfaction of the patients with the food services. RESULTS: The results showed that of 374 patients 51.3% evaluated food service quality adequate, 32.4% said that the food quality was inadequate, and 16.3% stated that they were uncertain. A logistic regression model was estimated in determining the most important and statistically significant factors affecting patient satisfaction with hospital foods and food services. The results showed that patient-specific demographic characteristics were insignificant in explaining satisfaction level with food services, but the variables of taste (OR = 9.853, p = 0.000) and appearance (OR = 2.687, p = 0.014) of the food were statistically significant and important determinants of patient satisfaction with the foods served at the hospital. CONCLUSIONS: The results of this study would be helpful in making decision on increasing the level of satisfaction of patients with the food services for hospital managers and the food (nutrition) departments. On the other hand, the results can also be used in benchmarking the hospital's food services quality with other hospitals, and in monitoring improvements in food services quality in the future.

Adolescent↗
PubMed1994

Pitfalls in the design and manufacture of infant formulae.

The composition of modern infant formulae is basically oriented on the "golden standard" human milk and influenced by several official regulations and recommendations (EC, ESPGAN, etc.). This article will focus on two recent improvements in the field of long-chain polyunsaturated fatty acids (LCPs) and protein hydrolysates. The addition of LCPs for preterm formulae was recommended recently by ESPGAN (the European Society for Pediatric Gastroenterology and Nutrition). Our research has focused on this problem for many years and we have found a good source of LCPs using specially prepared egg-yolk lipids. Others have used fish oils and run into the problem of growth retardation. Therefore, the possible sources of LCPs have to be discussed very critically and the alternatives will be shown. Also, new developments like the use of single-cell oils will be discussed. Second, the use of protein hydrolysates have been introduced for the so-called hypoantigenic or hypoallergenic formulae. Hypoantigenic formulae for preventive use have to be differentiated clearly from hypoallergenic formulae for treatment of proved cows' milk protein allergy. The problems of designing suitable hydrolysates that are low in antigenicity and good in taste will be outlined. The determination of the molecular weight distribution by gel chromatography will be compared critically with the newer techniques. The ELISA technique for testing the antigenicity is recommended before any in vivo evaluation. So far, the anaphylactic guinea-pig model is the most sensitive in vivo testing method. Summing up, modern infant formulae manufacture is much more dependent on modern laboratory techniques, which have to be chosen critically and must be adapted to the newest state of the art.

Fatty Acids, Unsaturated↗
PubMed1997

Intra-oral food manipulation of carp and other cyprinids: adaptations and limitations.

The heterogeneity of the cyprinid fishes (about 2000 species) and their feeding requires a general model of aquatic feeding. In this model the timing of mouth and gill slit opening and the relative contribution of head expansion and swimming are determining factors. The following elements have been distinguished in the feeding process of cyprinid fishes: search/choice, intake (particulate intake and gulping), size-and taste selection, intra-oral transport (including repositioning), mastication and deglutition. The recognition of these processes is based on the combined use of X-ray, cine film, video and emg techniques. Structural specialisations, including the intra-oral density of sensory elements and their central connections with associated feed back loops, enable a wide variety of combinations and regulation of (stereotyped) motor patterns.

Adaptation, Biological↗
PubMed1998

Detection of very complex taste mixtures.

Mixtures can often be tasted when all components are too weak to be tasted separately. Such mixtures are said to be integrative. Integration was demonstrated by mixing compounds in concentrations proportional to their separate detection thresholds and then measuring the detection threshold of the mixture as a whole by forced choice with plain water. Mixtures of 3, 6, 12 and 24 compounds were thus evaluated. With earlier data on 2-, 3- and 4-component mixtures, the results show that the concentration of any constituent compound goes down in approximate proportion to the number of compounds with which it is in mixture. This nearly complete integration describes mixtures of like-quality compounds, of unlike-quality compounds, and of both like- and unlike-quality compounds together. Integrative mixtures provide a model for the detection of the ultracomplex stimuli of everyday life, such as foods and drinking waters. Although the degree of integration may trail off slightly with mixtures of high complexity, the results proffer no limit on the number of compounds that can be at least partially integrated. In principle, integration permits detection of natural substances whose myriad components could all be far below threshold. The mechanism of taste integration is speculative, but the facts are congenial to the hypothesis of multiple parallel channels for the processing of intensity and quality.

Food↗
PubMed2004

Prenatal exposure of Long-Evans rats to 17alpha-ethinylestradiol modifies neither latent inhibition nor prepulse inhibition of the startle reflex but elicits minor deficits in exploratory behavior.

Prenatal administration of synthetic estrogens in humans as well as lower mammals was reported to alter behavior in adulthood. The alterations remain to be characterized according to specific pathophysiological hypotheses. In this study, three common behavioral models of schizophrenia were tested, i.e., latent inhibition (LI), prepulse inhibition of the startle response (PPI) and hyperlocomotion under amphetamine. Female Long-Evans rats were injected i.p. with a solution of 17alpha-ethinylestradiol (15 microg kg(-1)) everyday from day 9 to 14 of pregnancy, and behavioral characteristics of their offspring, raised by Wistar foster mothers, were compared to those of rats born from dams injected with the vehicle only, over the same gestation period. LI was tested in a conditioned taste aversion and a conditioned passive avoidance paradigm followed by a parametric study of PPI and an evaluation of locomotion in an open field under saline or amphetamine (1.5 mg kg(-1)). Histological brain measurements were also carried out in a subset of the same rats. Neither LI nor PPI was altered using methods that had proven sensitive in previous pharmacological studies. Treated rats' locomotion was impaired, but amphetamine did not elicit a differential enhancement. A thinner Amon's horn layer was observed in their hippocampus. This indicates that standard models of schizophrenia did not fit to the behavioral abnormalities found by others and confirmed in this study. They were not due to the abnormal maternal care to pups elicited by the treatment.

Amphetamine↗
PubMed1999

Alkylamides that produce tingling paresthesia activate tactile and thermal trigeminal neurons.

Alkylamides isolated from the fruit of Xanthoxylum, Szechuan pepper, produce a strong tingling sensation in the mouth. In order to determine the peripheral basis of this sensation, extracellular nerve recordings were obtained from the lingual nerve of rats. The primary pungent compound, hydroxy-alpha-sanshool (HO-alpha-S), altered the levels of spontaneous activity in cool-sensitive fibers as well as inducing activity in tactile fibers, cold nociceptors and silent fibers that were insensitive to innocuous thermal or tactile stimuli. Moreover, tactile or thermal sensitivity was induced in fibers that were initially insensitive to touch or cooling. The neuronal distribution of sensitivities to capsaicin and to HO-alpha-S indicate that this compound affects neurons mediating innocuous sensations. HO-alpha-S may be useful as a model stimulus for studies of paresthesia.

Alkanes↗
PubMed2002

Ironic processes in the eating behaviour of restrained eaters.

Theory. The present study examines the processes underlying the disinhibition of the eating behaviour of restrained eaters following negative emotions. Based on Herman and Polivy's (1984) Boundary Model and Wegner's Ironic Process Theory (1994), the limited capacity hypothesis is formulated, suggesting that overeating in restrained eaters results from cognitive capacity limitations. Predictions were that (1) impairment of cognitive capacity during eating will lead to overeating in restrained but not in unrestrained eaters and that (2) this difference should only emerge with food perceived to be high in calories.METHOD: The hypotheses were tested in an experiment with a 2 (restrained/unrestrained) x 2 (distraction yes/no) x 2 (perceived calories high/low) design, in which subjects consumed ice-cream in a taste test situation. Ice-cream consumption was the dependent variable.RESULTS: A second-order interaction was found: as predicted, in the high calorie condition restrained eaters ate the same amount as unrestrained eaters when not distracted, but considerably more when distracted. There was also an unexpected main effect of distraction, which indicated that restrained as well as unrestrained eaters ate more if distracted than if not distracted.DISCUSSION: The restraintxdistractionxperceived calories interaction can be explained by both the Ironic Process Theory and the Boundary Model; and the limited capacity hypothesis appears to be confirmed. The overall main effect of distraction remains puzzling. Two speculative views for the latter effect are offered.

Journal Article↗