Differential Gurmarin Suppression of Sweet Taste Responses in Rat Solitary Nucleus Neurons

2003 ◽  
Vol 90 (2) ◽  
pp. 911-923 ◽  
Author(s):  
Christian H. Lemon ◽  
Toshiaki Imoto ◽  
David V. Smith
Keyword(s):  
Cluster Analysis ◽  
Sucrose Concentration ◽  
Hierarchical Cluster ◽  
Initial Response ◽  
Sweet Taste ◽  
Induced Response ◽  
Response Suppression ◽  
Response Profiles ◽  
Neuronal Type ◽  
Concentration Series

We examined the effect of the sweet transduction blocker gurmarin on taste responses recorded from neurons in the rat solitary nucleus (NST) to determine how gurmarin sensitivity is distributed across neuronal type. Initially, responses evoked by washing the anterior tongue and palate with 0.5 M sucrose, 0.1 M NaCl, 0.01 M HCl, and 0.01 M quinine-HCl were recorded from 35 neurons. For some cells, responses to a sucrose concentration series (0.01–1.0 M) or an array of sweet-tasting compounds were also measured. Gurmarin (10 μg/ml, 2–4 ml) was then applied to the tongue and palate. Stimuli were reapplied after 10–15 min. Neurons were segregated into groups based on similarities among their initial response profiles using hierarchical cluster analysis (HCA). Results indicated that sucrose responses recorded from neurons representative of each HCA-defined class were suppressed by gurmarin. However, a disproportionate percentage of cells in each group displayed sucrose responses that were substantially attenuated after gurmarin treatment. Postgurmarin sucrose responses recorded from neurons that composed 57% of class S, 40% of class N, and 33% of class H were suppressed by ≥50% relative to control. On average, attenuation was statistically significant only in class S and N neurons. Although the magnitude of gurmarin-induced response suppression did not differ across sucrose concentration, responses to different sweet-tasting compounds were differentially affected. Responses to NaCl, HCl, or quinine were not suppressed by gurmarin. Results suggest that information from gurmarin-sensitive and -insensitive receptor processes converges onto single NST neurons.

scholarly journals Quantifying Sweet Taste Liker Phenotypes: Time for Some Consistency in the Classification Criteria

Nutrients ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 129 ◽  
Author(s):  
Vasiliki Iatridi ◽  
John Hayes ◽  
Martin Yeomans
Keyword(s):  
Cluster Analysis ◽  
Young Adults ◽  
Hierarchical Cluster ◽  
Sweet Taste ◽  
Classification Criteria ◽  
Ingestive Behavior ◽  
Response Patterns ◽  
Sucrose Solutions ◽  
Liking Rating

Taste hedonics is a well-documented driver of food consumption. The role of sweetness in directing ingestive behavior is largely rooted in biology. One can then intuit that individual differences in sweet-liking may constitute an indicator of variations in the susceptibility to diet-related health outcomes. Despite half a century of research on sweet-liking, the best method to identify the distinct responses to sweet taste is still debated. To help resolve this issue, liking and intensity ratings for eight sucrose solutions ranging from 0 to 1 M were collected from 148 young adults (29% men). Hierarchical cluster analysis (HCA) revealed three response patterns: a sweet-liker (SL) phenotype characterized by a rise in liking as concentration increased, an inverted U-shaped phenotype with maximum liking at 0.25 M, and a sweet-disliker (SD) phenotype characterized by a decline in liking as a function of concentration. Based on sensitivity and specificity analyses, present data suggest the clearest discrimination between phenotypes is seen with 1.0 M sucrose, where a liking rating between −15 and +15 on a −50/+50 scale reliably distinguished individuals with an inverted U-shaped response from the SLs and the SDs. If the efficacy of this approach is confirmed in other populations, the discrimination criteria identified here can serve as the basis for a standard method for classifying sweet taste liker phenotypes in adults.

Gustatory neuron types in hamster brain stem

1983 ◽  
Vol 50 (2) ◽  
pp. 522-540 ◽  
Author(s):  
D. V. Smith ◽  
R. L. Van Buskirk ◽  
J. B. Travers ◽  
S. L. Bieber
Keyword(s):  
Cluster Analysis ◽  
Brain Stem ◽  
Hierarchical Cluster Analysis ◽  
Nucleus Tractus Solitarius ◽  
Hierarchical Cluster ◽  
Neural Response ◽  
Response Functions ◽  
Gustatory System ◽  
Chorda Tympani Nerve ◽  
Response Profiles

In general, mammalian taste neurons are broadly responsive to stimuli representing different taste qualities. In the hamster, this breadth of tuning increases systematically from peripheral to successively higher brain stem neurons. Some investigators have classified taste-responsive neurons into "best-stimulus" categories on the basis of which of the four basic stimuli (sucrose, NaCl, HCl, or quinine hydrochloride) elicits the maximum response. However, attempts by others to demonstrate the existence of taste neuron types in the chorda tympani nerve and medulla of the rat using hierarchical cluster analysis have not been successful, resulting in the conclusion that there are no neuron types in the rat gustatory system. The present study was designed to look at the question of neuron types in the hamster, a species with a broader range of gustatory sensitivities to anterior tongue stimulation. Responses of 30 neurons in the nucleus tractus solitarius (NTS) and 31 neurons in the parabrachial nuclei (PbN) of the hamster to an array of 18 stimulus compounds were recorded extracellularly. The similarities of the neural response profiles of these cells at each synaptic level were compared using multivariate statistical techniques. The possiblee grouping of cells on the basis of similarities in their response functions was examined with hierarchical cluster analysis, and the relationships among these response functions were examined with multidimensional scaling. The results of the cluster analysis suggested that at both the NTS and PbN, there are three clusters of neural response profiles. These three clusters of response profiles are characterized at both synaptic levels by their predominant sensitivity to 1) sucrose and other sweet-tasting compounds, 2) sodium salts, and 3) nonsodium salts and acids. Representation of these neurons in a two-dimensional space yielded three nonoverlapping groups of cells in both the NTS and PbN, corresponding to the three groups identified by the hierarchical cluster solution. Classification of taste neurons either by their best stimulus or by other criteria has been criticized on the grounds that it may constitute an arbitrary division of a continuous population of neurons. The techniques of numerical taxonomy, which take the cells' variability into account, also result in a grouping of taste cells into classes. These taxonomic classes agree in most instances (80% in NTS and 80.6% in PbN) to a best-stimulus classification. The failure of some investigators to find types of neural response profiles in the rat gustatory system may be the result of species differences in taste sensitivity as well as differences in the statistical procedures employed.

scholarly journals The organization of taste sensibilities in hamster chorda tympani nerve fibers.

1988 ◽  
Vol 91 (6) ◽  
pp. 861-896 ◽  
Author(s):  
M E Frank ◽  
S L Bieber ◽  
D V Smith
Keyword(s):  
Cluster Analysis ◽  
Factor Analysis ◽  
Hierarchical Cluster Analysis ◽  
Nerve Impulse ◽  
Hierarchical Cluster ◽  
Nerve Fibers ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Activation Patterns ◽  
Response Profiles

Electrophysiological measurements of nerve impulse frequencies were used to explore the organization of taste sensibilities in single fibers of the hamster chorda tympani nerve. Moderately intense taste solutions that are either very similar or easily discriminated were applied to the anterior lingual surface. 40 response profiles or 13 stimulus activation patterns were considered variables and examined with multivariate statistical techniques. Three kinds of response profiles were seen in fibers that varied in their overall sensitivity to taste solutions. One profile (S) showed selectivity for sweeteners, a second (N) showed selectivity for sodium salts, and a third (H) showed sensitivity to salts, acids, and other compounds. Hierarchical cluster analysis indicated that profiles fell into discrete classes. Responses to many pairs of effective stimuli were covariant across profiles within a class, but some acidic stimuli had more idiosyncratic effects. Factor analysis of profiles identified two common factors, accounting for 77% of the variance. A unipolar factor was identified with the N profile, and a bipolar factor was identified with the S profile and its opposite, the H profile. Three stimulus activation patterns were elicited by taste solutions that varied in intensity of effect. Hierarchical cluster analysis indicated that the patterns fell into discrete classes. Factor analysis of patterns identified three common unipolar factors accounting for 82% of the variance. Eight stimuli (MgSO4, NH4Cl, KCl, citric acid, acetic acid, urea, quinine HCl, HCl) selectively activated fibers with H profiles, three stimuli (fructose, Na saccharin, sucrose) selectively activated fibers with S profiles, and two stimuli (NaNO3, NaCl) activated fibers with N profiles more strongly than fibers with H profiles. Stimuli that evoke different patterns taste distinct to hamsters. Stimuli that evoke the same pattern taste more similar. It was concluded that the hundreds of peripheral taste neurons that innervate the anterior tongue play one of three functional roles, providing information about one of three features that are shared by different chemical solutions.

scholarly journals The Effect of Sleep Curtailment on Hedonic Responses to Liquid and Solid Food

Foods ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 465 ◽  
Author(s):  
Edward J. Szczygiel ◽  
Sungeun Cho ◽  
Robin M. Tucker
Keyword(s):  
Cluster Analysis ◽  
Energy Intake ◽  
Hierarchical Cluster Analysis ◽  
Single Channel ◽  
Hierarchical Cluster ◽  
Sweet Taste ◽  
Primary Objective ◽  
Taste Perception ◽  
Model Systems ◽  
Food Matrices

It is currently unclear whether changes in sweet taste perception of model systems after sleep curtailment extend to complex food matrices. Therefore, the primary objective of this study was to use a novel solid oat-based food (crisps) and oat-based beverage stimulus sweetened with sucralose to assess changes in taste perception after sleep curtailment. Forty-one participants recorded a habitual and curtailed night of sleep using a single-channel electroencephalograph. The next morning, overall sweetness, flavor, and texture liking responses to energy- and nutrient-matched oat products across five concentrations of sweetness were measured. Overall (p = 0.047) and flavor (p = 0.017) liking slopes across measured concentrations were steeper after curtailment, suggesting that sweeter versions of the oat products were liked more after sleep curtailment. Additionally, a hierarchical cluster analysis was used to classify sweet likers and non-likers. While the effect of sleep curtailment on sweet liking did not differ between sweet liking classification categories, sleep curtailment resulted in decreased texture liking in the solid oat crisps for sweet non-likers (p < 0.001), but not in the oat beverage. These findings illustrate the varied effects of sleep on hedonic response in complex food matrices and possible mechanisms by which insufficient sleep can lead to sensory-moderated increases in energy intake.

DRSA: a non-hierarchical clustering algorithm using k-NN graph and its application in vegetation classification

2015 ◽  
pp. 125-138 ◽  
Author(s):  
I. V. Goncharenko
Keyword(s):  
Cluster Analysis ◽  
Clustering Algorithm ◽  
Nearest Neighbor ◽  
Clustering Algorithms ◽  
Protein Structures ◽  
Hierarchical Cluster ◽  
Vegetation Classification ◽  
K Nearest Neighbor ◽  
Neighbor Graph ◽  
Nearest Neighbor Graph

In this article we proposed a new method of non-hierarchical cluster analysis using k-nearest-neighbor graph and discussed it with respect to vegetation classification. The method of k-nearest neighbor (k-NN) classification was originally developed in 1951 (Fix, Hodges, 1951). Later a term “k-NN graph” and a few algorithms of k-NN clustering appeared (Cover, Hart, 1967; Brito et al., 1997). In biology k-NN is used in analysis of protein structures and genome sequences. Most of k-NN clustering algorithms build «excessive» graph firstly, so called hypergraph, and then truncate it to subgraphs, just partitioning and coarsening hypergraph. We developed other strategy, the “upward” clustering in forming (assembling consequentially) one cluster after the other. Until today graph-based cluster analysis has not been considered concerning classification of vegetation datasets.

Quality evaluation of tugaksheeree samples by ATR-FTIR spectroscopy using multicomponent analysis

2020 ◽  
Vol 10 ◽  
Author(s):  
Nikunj D. Patel ◽  
Niranjan S. Kanaki
Keyword(s):  
Principal Component Analysis ◽  
Cluster Analysis ◽  
Quality Evaluation ◽  
Principal Component ◽  
Hierarchical Cluster ◽  
Attenuated Total Reflectance ◽  
Chemometric Methods ◽  
Total Reflectance ◽  
Fingerprint Region ◽  
Ftir Technique

Background: Numerous Ayurvedic formulations contains tugaksheeree as key ingredient. Tugaksheereeis the starch gained from the rhizomes of two plants, Curcuma angustifoliaRoxb. (Zingiberaceae) and Marantaarundinacea (MA) Linn. (Marantaceae). Objective: The primary concerns in quality assessment of Tugaksheeree occur due to adulteration or substitution. Method: In current study, Fourier transform infrared (FTIR) technique with attenuated total reflectance (ATR) facility was used to evaluate tugaksheeree samples. Total 10 different samples were studied and transmittance mode was kept to record the spectra devoid of pellets of KBR. Further treatment was given with multi component tools by considering fingerprint region of the spectra. Multivariate analysis was performed by various chemometric methods. Result: Multi component methods like Principal Component Analysis (PCA), and Hierarchical Cluster Analysis (HCA)were used to discriminate the tugaksheeree samples using Minitab software. Conclusion: This method can be used as a tool to differentiate samples of tugaksheeree from its adulterants and substitutes.

Extraordinary circumstances: Covid-19 – Italian Serie A scenario

2021 ◽  
pp. 175433712110192
Author(s):  
Milan Radojicic ◽  
Aleksandar Djokovic ◽  
Nikola Cvetkovic
Keyword(s):  
Cluster Analysis ◽  
Hierarchical Cluster Analysis ◽  
Hierarchical Cluster ◽  
Round Robin ◽  
The Past ◽  
Novel Approach ◽  
Round Robin Tournaments

Unpredictable and uncontrollable situations have happened throughout history. Inevitably, such situations have an impact on various spheres of life. The coronavirus disease 2019 has affected many of them, including sports. The ban on social gatherings has caused the cancellation of many sports competitions. This paper proposes a methodology based on hierarchical cluster analysis (HCA) that can be applied when a need occurs to end an interrupted tournament and the conditions for playing the remaining matches are far from ideal. The proposed methodology is based on how to conclude the season for Serie A, a top-division football league in Italy. The analysis showed that it is reasonable to play 14 instead of the 124 remaining matches of the 2019–2020 season to conclude the championship. The proposed methodology was tested on the past 10 seasons of the Serie A, and its effectiveness was confirmed. This novel approach can be used in any other sport where round-robin tournaments exist.

scholarly journals Sexual behaviour patterns and STI risk: results of a cluster analysis among men who have sex with men in Portugal

BMJ Open ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. e033290
Author(s):  
Karel Blondeel ◽  
Sonia Dias ◽  
Martina Furegato ◽  
Armando Seuc ◽  
Ana Gama ◽  
...  
Keyword(s):  
Cluster Analysis ◽  
Sexual Behaviour ◽  
Hierarchical Cluster ◽  
Risk Behaviour ◽  
Sexual Partners ◽  
Hiv Positive ◽  
Research Approach ◽  
Cross Sectional ◽  
Combination Prevention ◽  
Sex With Men

ObjectivesPortugal has the highest HIV incidence rate in Western Europe. The proportion assigned to sexual contact between men recently increased to more than 30% of all HIV infections. Men who have sex with men (MSM) are vulnerable to the acquisition of other sexually transmitted infections (STIs), increasing the per-contact risk of HIV infection. Building on syndemic theory, the aim of this analysis was to identify patterns of current sexual behaviour in MSM, and explore their relationship with self-reported current, past STI diagnoses and HIV positive serostatus.DesignA cross-sectional behavioural survey was conducted in Portugal among MSM, using a community-based participatory research approach. Hierarchical cluster analysis was used to identify patterns including behavioural and demographic factors.ResultsThe analysis resulted in six clusters. Three clusters showed higher rates of current STI diagnosis (ranging from 11.7% to 17.1%), past STI diagnosis (ranging from 25.5% to 41.5%) and HIV positive serostatus (ranging from 13.0% to 16.7%). From the three clusters scoring lower on current and past STI and HIV diagnoses, one was characterised by a high number of sexual partners (62% had more than 12 partners in the last year), a high proportion (94.6%) of frequent visits to gay venues to meet sexual partners and high alcohol use (46.1%). The other two clusters scored lower on high risk sexual behaviour.ConclusionFactors other than sexual behaviour appear to reinforce the vulnerability to STIs and HIV of some MSM in this study, suggesting a syndemic of STIs, HIV and other adverse conditions. More research is needed to better understand the drivers of the STI/HIV epidemic in Portuguese MSM, using a concept that goes beyond risk behaviour, to develop effective combination prevention interventions.

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