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Results for “Taste modeling”

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At least 307 records · Page 17Linked to original sources
PubMed1969

Regulation of taste acuity by thiols and metal ions.

The administration of thiol-containing drugs decreases taste acuity in man and animals. Copper (II) and zine (II) administration returns taste acuity to normal levels. The results suggest that (1) thiols and metals are in dynamic equilibrium in the metabolic net, (2) regulation of taste acuity occurs through changes which thiols and/or metals bring about in the conformation of a protein which lines the pore of the taste receptor and its membrane, and (3) thiols normally play an inhibitory role in taste.

Animals↗
PubMed2006

Do we taste fat?

Sense of taste informs the body about the quality of ingested foods. Five sub-modalities allowing the perception of sweet, salty, sour, bitter, and umami stimuli are classically depicted. However, the inborn attraction of mammals for fatty foods raises the possibility of an additional orosensory modality devoted to fat perception. For a long time, dietary lipids were thought to be detected only by trigeminal (texture perception), retronasal olfactory, and post-ingestive cues. This minireview analyses recent findings showing that gustation also plays a significant role in dietary lipid perception.

Animals↗
PubMed2005

Brain-derived neurotrophic factor enhances conditioned taste aversion retention.

Brain-derived neurotrophic factor (BDNF) has recently emerged as one of the most potent molecular mediators of not only central synaptic plasticity, but also behavioral interactions between an organism and its environment. Our previous studies on the insular cortex (IC), a region of the temporal cortex implicated in the acquisition and storage of conditioned taste aversion (CTA), have demonstrated that induction of long-term potentiation (LTP) in the projection from the basolateral nucleus of the amygdala (Bla) to the IC, previous to CTA training, enhances the retention of this task. Recently, we found that intracortical microinfusion of BDNF induces a lasting potentiation of synaptic efficacy in the Bla-IC projection of adult rats in vivo. In this work, we present experimental data showing that intracortical microinfusion of BDNF previous to CTA training enhances the retention of this task. These findings support the concept that BDNF may contribute to memory-related functions performed by a neocortical area, playing a critical role in long-term synaptic plasticity.

Animals↗
PubMed2002

Quantitative model studies on the efficiency of precursors in the formation of cooling-active 1-pyrrolidinyl-2-cyclopenten-1-ones and bitter-tasting cyclopenta-[b]azepin-8(1H)-ones.

The yields of the cooling-active compounds 3-methyl-2-(1-pyrrolidinyl)-2-cyclopenten-1-one (1) and 5-methyl-2-(1-pyrrolidinyl)-2-cyclopenten-1-one (2) as well as the bitter tastants 7-methyl-2,3,6,7-tetrahydrocyclopenta-[b]azepin-8(1H)-one (3) and 7-methyl-2,3,4,5,6,7-hexahydrocyclopenta-[b]azepin-8(1H)-one (4) obtained by heating mixtures of possible Maillard-type precursors in model systems varying in temperature, pH value, or water content were determined quantitatively. The results showed that hexose-derived cyclotene is the common precursor for all four tastants and that the formation of each individual tastant is strongly determined by the structure of the nitrogen-containing precursor, e.g., reaction of cyclotene with pyrrolidine formed by thermal decarboxylation of L-proline produced the cooling compounds 1 and 2 only, whereas in the presence of 1-pyrroline formed upon Strecker reactions of L-proline, the bitter tasting azepinone 3 was produced exclusively. In contrast, the structure of the secondary amino acid L-proline enabled the formation of compound 4, whereas the pyrrolidine and 1-pyrroline, respectively, do not generate this tastant. In addition, a nonvolatile, tasteless intermediate, (S)-3-methyl-2-[(2'-carboxy)-1-pyrrolidinyl]-2-cyclopenten-1-one (5), was isolated from the cyclotene/L-proline reaction mixture and could be confirmed as an efficient precursor for the cooling compound 1. The data, obtained by these studies, are the scientific basis to tailor the desired overall flavor of foods by means of a more controlled Maillard-type technology.

Amino Acids↗
PubMed1998

Focused attention and the detectability of weak gustatory stimuli. Empirical measurement and computer simulations.

Attentional processes can modulate the detectability of weak stimuli; for example, the detectability of visual or auditory signals can depend on whether attention is allocated to the appropriate spatial location (vision) or acoustic frequency (hearing). Earlier attempts in the first author's laboratory to find analogous effects of focused attention on the detectability of taste stimuli were equivocal, in part it seems because human gustatory sensitivity can fluctuate substantially over time, a serious problem when using procedures that track sensitivity (d') to a constant stimulus concentration. To circumvent this problem, we adopted an adaptive psychophysical procedure, the transformed up-down method, using a 3-down/1-up rule to determine how the threshold to detect weak concentrations of sucrose and citric acid depended on whether the stimulus presented in a given two-alternative, forced-choice trial was expected or unexpected. The results showed threshold sensitivity to be slightly but consistently poorer when the test stimulus was unexpected (e.g., sucrose presented when citric acid was expected) than it was when the test stimulus was expected (e.g., sucrose presented when sucrose was expected). In this attentional paradigm, the unexpected stimulus must perforce be presented on only a small fraction of the trials. In selecting a procedure, we chose a 3-down/1-up adaptive rule rather than the more popular 2-down/1-up rule, a choice that turned out to be in line with results of Monte Carlo computer simulations. These simulations suggest that across a wide range of conditions (starting stimulus concentrations, step sizes), the variability in threshold measurements can be smaller with a 3-down/1-up rule than with a 2-down/1-up rule, even when the total number of trials is the same and not very great.

Attention↗
PubMed2004

Biochemical modulation of NMDA receptors: role in conditioned taste aversion.

Glutamate neurotransmission plays a crucial role in a variety of functions in the central nervous system, including learning and memory. However, little is known about the mechanisms underlying this process in mammals because of the scarceness of experimental models that permit correlation of behavioral and biochemical changes occurring during the different stages of learning and the retrieval of the acquired information. One model that has been useful to study these mechanisms is conditioned taste aversion (CTA), a paradigm in which animals learn to avoid new tastes when they are associated with gastrointestinal malaise. Glutamate receptors of the N-methyl-D-aspartate (NMDA) type appear to be necessary in this process, because blockade of this receptor prevents CTA. Phosphorylation of the main subunits of the NMDA receptor is a well-established biochemical mechanism for the modulation of the receptor response. Such modulation seems to be involved in CTA, because inhibitors of protein kinase C (PKC) block CTA acquisition and because the exposure to an unfamiliar taste results in an increased phosphorylation of tyrosine and serine residues of the NR2B subunit of the receptor in the insular cortex, the cerebral region where gustatory and visceral information converge. In this work we review these mechanisms of NMDA receptor modulation in CTA.

Animals↗
PubMed2003

Vestibular lesions selectively abolish body rotation-induced, but not lithium-induced, conditioned taste aversions (oral rejection responses) in rats.

Pairing a novel taste with provocative vestibular stimulation results in conditioned taste aversions in both rats and humans. Vestibular system involvement in gustatory conditioning was examined in sham-lesioned or labyrinthectomized rats. Three conditioning trials consisted of 30 min access to asaccharin (0.1%) solution followed by 30 min of rotation (70 rpm) or sham rotation. In a taste reactivity test with saccharin, rotated sham-lesioned rats, but not labyrinthectomized rats, exhibited increased oral rejection reactions compared with control rats. When conditioned with lithium chloride, both labyrinthectomized and sham-lesioned rats displayed robust conditioned rejection reactions. The finding that normal vestibular function is necessary in obtaining rotation-induced conditioned taste aversions supports the face and construct validity of a rat model of motion sickness.

Animals↗
PubMed2000

Comparative study of texture of normal and energy reduced sponge cakes.

The complete sucrose elimination and its replacement by microencapsulated aspartame (Nutra Sweet) and bulking agents (sorbitol, wheat starch and wheat germ) on the physical and textural sensory characteristics of two diabetic sponge cakes against a control sponge cake was studied. Mathematical and statistical methods were used and regression models worked out, describing the physical and textural characteristics of the three sponge cakes and their values were optimized. The effect on the porosity, springiness, volume and shrinkage of sponge takes was substantial and depended on the amount of the added ingredients. The diabetic sponge cake containing wheat germ showed the least physical and sensory deviations against the control sponge cake. The energy value of the diabetic sponge cakes against the control one was reduced with 25% for the ordinary sponge cake without sucrose and with 29% for sponge cake without sucrose containing wheat germ.

Aspartame↗
PubMed2001

Post-ingestive positive controls of ingestive behavior.

Post-ingestive negative controls of ingestive behavior are well characterized. Nutrients act in the gut to inhibit meal size by direct actions on feeding and by conditioning a satiation response to orosensory (flavor) stimuli. Accumulating evidence indicates that there are also post-ingestive positive controls of ingestion that operate by conditioning flavor preference and increased acceptance. In several experiments rats trained to consume a flavored solution paired with intragastric carbohydrate infusions significantly increased their solution intake. Drinking bout size and number, and lick rates and burst size were also increased by carbohydrate infusions. Whether intake is stimulated or inhibited by post-ingestive nutrient actions depends upon several factors, including most notably nutrient concentration. Post-ingestive positive controls need to be incorporated into theoretical models of ingestive behavior.

Animals↗
PubMed1995

A method to mimic and to study the release of flavour compounds from chewed food.

A method for analysing the flavour release from chewed food has been developed. Flavour release is studied in an artificial mouth simulating the process of chewing and using fluid model systems, in our case aromatised oil in water emulsions. The fast transfer of volatile substances from the chewpulp into the gaseous phase is followed up by comparing six quickly taken gas samples. Volatile substances are analysed by means of a special technique which includes cryofocusing and capillary gas chromatography. As a wide spectrum of individual volatile substances is considered, systematic investigations into the flavour release from food under mouth-typical conditions are possible.

Butter↗
PubMed2005

Odor/taste integration and the perception of flavor.

Perceptions of the flavors of foods or beverages reflect information derived from multiple sensory afferents, including gustatory, olfactory, and somatosensory fibers. Although flavor perception therefore arises from the central integration of multiple sensory inputs, it is possible to distinguish the different modalities contributing to flavor, especially when attention is drawn to particular sensory characteristics. Nevertheless, our experiences of the flavor of a food or beverage are also simultaneously of an overall unitary perception. Research aimed at understanding the mechanisms behind this integrated flavor perception is, for the most part, relatively recent. However, psychophysical, neuroimaging and neurophysiological studies on cross-modal sensory interactions involved in flavor perception have started to provide an understanding of the integrated activity of sensory systems that generate such unitary perceptions, and hence the mechanisms by which these signals are "functionally united when anatomically separated". Here we review this recent research on odor/taste integration, and propose a model of flavor processing that depends on prior experience with the particular combination of sensory inputs, temporal and spatial concurrence, and attentional allocation. We propose that flavor perception depends upon neural processes occurring in chemosensory regions of the brain, including the anterior insula, frontal operculum, orbitofrontal cortex and anterior cingulate cortex, as well as upon the interaction of this chemosensory "flavor network" with other heteromodal regions including the posterior parietal cortex and possibly the ventral lateral prefrontal cortex.

Animals↗