scholarly journals Gustatory neural responses to umami stimuli in the parabrachial nucleus of C57BL/6J mice

2012 ◽  
Vol 107 (6) ◽  
pp. 1545-1555 ◽  
Author(s):  
Kenichi Tokita ◽  
Takashi Yamamoto ◽  
John D. Boughter
Keyword(s):  
Hierarchical Cluster ◽  
Taste Quality ◽  
Multidimensional Analysis ◽  
Parabrachial Nucleus ◽  
Chorda Tympani Nerve ◽  
Unit Recording ◽  
Umami Taste ◽  
Basic Taste ◽  
The Central Nervous System ◽  
Central Representation

Umami is considered to be the fifth basic taste quality and is elicited by glutamate. The mouse is an ideal rodent model for the study of this taste quality because of evidence that suggests that this species, like humans, may sense umami-tasting compounds as unique from other basic taste qualities. We performed single-unit recording of taste responses in the parabrachial nucleus (PbN) of anesthetized C57BL/6J mice to investigate the central representation of umami taste. A total of 52 taste-responsive neurons (22 sucrose-best, 19 NaCl-best, 5 citric acid-best, and 6 quinine-best) were recorded from stimulation period with a large panel of basic and umami-tasting stimuli. No neuron responded best to monopotassium glutamate (MPG) or inosine 5′-monophosphate (IMP), suggesting convergence of input in the central nervous system. Synergism induced by an MPG-IMP mixture was observed in all sucrose-best and some NaCl-best neurons that possessed strong sensitivity to sucrose. In more than half of sucrose-best neurons, the MPG-IMP mixture evoked stronger responses than those elicited by their best stimulus. Furthermore, hierarchical cluster analysis and multidimensional analysis indicated close similarity between sucrose and the MPG-IMP mixture. These results strongly suggest the mixture tastes sweet to mice, a conclusion consistent with previous findings that show bidirectional generalization of conditioned taste aversion between sucrose and umami mixtures, and suppression of taste responses to both sucrose and mixtures by the antisweet polypeptide gurmarin in the chorda tympani nerve. The distribution pattern of reconstructed recording sites of specific neuron types suggested chemotopic organization in the PbN.

Gustatory responses of cortical neurons in rats. II. Information processing of taste quality

1985 ◽  
Vol 53 (6) ◽  
pp. 1356-1369 ◽  
Author(s):  
T. Yamamoto ◽  
N. Yuyama ◽  
T. Kato ◽  
Y. Kawamura
Keyword(s):  
Cortical Neurons ◽  
Neural Coding ◽  
Response Pattern ◽  
Present Report ◽  
Correlation Coefficients ◽  
Taste Quality ◽  
Pattern Theory ◽  
Response Characteristics ◽  
Basic Taste ◽  
Neuron Response

The present report was designed to investigate neural coding of taste information in the cerebral cortical taste area of rats. The magnitude and/or type (excitatory, inhibitory, or no-response) of responses of 111 cortical neurons evoked by single concentrations of the four basic taste stimuli (sucrose, NaCl, HCl, and quinine HCl) were subjected to four types of analyses in the context of the four proposed hypotheses of taste-quality coding: across-neuron response-pattern, labeled-line, matrix-pattern, and across-region response-pattern notions (88 histologically located neurons). An across-neuron response-pattern notion assumes that taste quality is coded by differential magnitudes of response across many neurons. This theory utilizes across-neuron correlation coefficients as a metric for the evaluation of taste quality coding. Across-neuron correlations between magnitudes of responses to any pairs of the four basic taste stimuli across 111 cortical neurons were very high and were similar. However, calculations made with net responses (spontaneous rate subtracted) resulted in less positive correlations but still similar values among the various pairs of taste stimuli. This finding suggests that across-neuron response patterns of cortical neurons become less discriminating among taste qualities compared with those of the lower-order neurons. A labeled-line notion assumes that there are identifiable groups of neurons and that taste quality is coded by activity in these particular sets of neurons. Some investigators have classified taste-responsive neurons into best-stimulus categories, depending on their best sensitivity to any one of the four basic stimuli, such as sucrose-best, NaCl-best, HCl-best, and quinine-best neurons; they have suggested that taste can be classified along four qualitative dimensions that correspond to these four neuron types (i.e., four labeled lines). The present study shows that responsiveness of each of the four best-stimulus neurons had similar profiles between peripheral and cortical levels. That is, when the stimuli were arranged along the abscissa in the order of sucrose, NaCl, HCl, and quinine, there is a peak response in one place, and the responses decreased gradually from the peak. However, such response characteristics do not favor the labeled-line theory, since they can be explained in the context of the across-neuron pattern theory. A matrix-pattern notion assumes that taste quality is coded by a spatially arranged matrix pattern of activated neurons.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Temporal coding of taste in the parabrachial nucleus of the pons of the rat

2011 ◽  
Vol 105 (4) ◽  
pp. 1889-1896 ◽  
Author(s):  
Andrew M. Rosen ◽  
Jonathan D. Victor ◽  
Patricia M. Di Lorenzo
Keyword(s):  
Time Course ◽  
Temporal Dynamics ◽  
Spike Timing ◽  
Temporal Coding ◽  
Taste Quality ◽  
Spike Count ◽  
Parabrachial Nucleus ◽  
Similar Proportion ◽  
Temporal Characteristics ◽  
Temporal Precision

Recent studies have provided evidence that temporal coding contributes significantly to encoding taste stimuli at the first central relay for taste, the nucleus of the solitary tract (NTS). However, it is not known whether this coding mechanism is also used at the next synapse in the central taste pathway, the parabrachial nucleus of the pons (PbN). In the present study, electrophysiological responses to taste stimuli (sucrose, NaCl, HCl, and quinine) were recorded from 44 cells in the PbN of anesthetized rats. In 29 cells, the contribution of the temporal characteristics of the response to the discrimination of various taste qualities was assessed. A family of metrics that quantifies the similarity of two spike trains in terms of spike count and spike timing was used. Results showed that spike timing in 14 PbN cells (48%) conveyed a significant amount of information about taste quality, beyond what could be conveyed by spike count alone. In another 14 cells (48%), the rate envelope (time course) of the response contributed significantly more information than spike count alone. Across cells there was a significant correlation ( r = 0.51; P < 0.01) between breadth of tuning and the proportion of information conveyed by temporal dynamics. Comparison with previous data from the NTS (Di Lorenzo PM and Victor JD. J Neurophysiol 90: 1418–31, 2003 and J Neurophysiol 97: 1857–1861, 2007) showed that temporal coding in the NTS occurred in a similar proportion of cells and contributed a similar fraction of the total information at the same average level of temporal precision, even though trial-to-trial variability was higher in the PbN than in the NTS. These data suggest that information about taste quality conveyed by the temporal characteristics of evoked responses is transmitted with high fidelity from the NTS to the PbN.

scholarly journals Response properties of macaque monkey chorda tympani fibers.

1975 ◽  
Vol 66 (6) ◽  
pp. 781-810 ◽  
Author(s):  
M Sato ◽  
H Ogawa ◽  
S Yamashita
Keyword(s):  
Macaque Monkey ◽  
Squirrel Monkeys ◽  
Taste Quality ◽  
Chorda Tympani ◽  
Macaque Monkeys ◽  
Response Properties ◽  
Basic Taste ◽  
Quinine Hydrochloride ◽  
Positive Correlations ◽  
Higher Sensitivity

Many of the chorda tympani fibers of crab-eating monkeys respond to more than one of the four basic stimuli (NaCl, sucrose, HCl, and quinine hydrochloride) as well as cooling or warming of the tongue. Fibers could be classified into four categories depending on their best sensitivity to any one of the four basic stimuli. Sucrose-best and quinine-best fibers are rather specifically sensitive to sucrose and quinine, respectively, while salt-best and acid-best fibers respond relatively well to HCl and NaCl, respectively. Saccharin, dulcin, and Pb acetate produce a good response in sucrose-best fibers, but quinine-best and salt-best fibers also respond to saccharin. Highly significant positive correlations exist between amounts of responses to sucrose and those to saccharin, dulcin, and Pb acetate, indicating that these substances produce in the monkey a taste quality similar to that produced by sucrose. Compared with chroda tympani fibers of rats, hamsters, and squirrel monkeys, macaque monkey taste fibers are more narrowly tuned to one of the four basic taste stimuli and more highly developed in sensitivity to various sweet-tasting substances. Also LiCl and NaCl are more effective stimuli for gustatory receptors in macaque monkeys than NH4Cl and KCl. This contrasts with a higher sensitivity to KCl and NH4Cl than to NaCl in chorda tympani fibers of squirrel monkeys.

Substance and tongue-region specific loss in basic taste-quality identification in elderly adults

2006 ◽  
Vol 264 (3) ◽  
pp. 285-289 ◽  
Author(s):  
Steven Nordin ◽  
Annika Brämerson ◽  
Eva Bringlöv ◽  
Gerd Kobal ◽  
Thomas Hummel ◽  
...  
Keyword(s):  
Taste Quality ◽  
Elderly Adults ◽  
Specific Loss ◽  
Basic Taste

scholarly journals Historical retrospective of the Neurophysiological Laboratory of the Faculty of Medicine in Novi Sad

2018 ◽  
Vol 146 (11-12) ◽  
pp. 694-699
Author(s):  
Nada Naumovic ◽  
Danijel Slavic ◽  
Dea Karaba-Jakovljevic ◽  
Maja Bogdan ◽  
Olga Ivetic
Keyword(s):  
Nervous System ◽  
Great Influence ◽  
Unit Recording ◽  
Scientific Curiosity ◽  
Clinical Investigations ◽  
The Central Nervous System ◽  
Stereotactic Method ◽  
Novi Sad ◽  
Behaviour Learning ◽  
Scientific Achievements

Over the course of several decades at the Faculty of Medicine in Novi Sad, fundamental studies in the field of neurosciences were of great importance and were continually kept up-to-date with global scientific achievements. These studies were applied by using the stereotactic method, single-unit recording, and electroencephalography. The Laboratory of Neurophysiology was established in 1965 and since 1978 microelectrode and microiontophoretic techniques important for the registration and analysis of the activity of individual neurons were fully developed. Under the great influence of Russian neurophysiological school (P.K. Anokhin, K.V. Sudakov), the emphasis was on the study of Anokhin?s theory of functional systems. Recently, epilepsy, brain ischemia and the influence of different medications, auxiliary medicinal products, and physical agents (electromagnetic radiation) on the central nervous system, behaviour, learning and investigated pathological conditions have been studied. Scientific collaboration with renowned institutions in the country and abroad has been established, numerous scientific projects have been carried out, expert international meetings have been organized, and numerous significant studies have been published. These results have often been the basis for further clinical investigations and the improvement of preventive or curative treatment of patients. Researchers from the Laboratory participated in the education of new generations of neurophysiologists, encouraging their scientific curiosity and love for fascinating mechanisms of the nervous system.

Responses of primate cortical neurons to unitary and binary taste stimuli

1996 ◽  
Vol 75 (1) ◽  
pp. 396-411 ◽  
Author(s):  
Y. Miyaoka ◽  
T. C. Pritchard
Keyword(s):  
Cortical Neurons ◽  
Principal Axis ◽  
Monosodium Glutamate ◽  
Multidimensional Analysis ◽  
Multidimensional Space ◽  
Stimulus Similarity ◽  
Basic Taste ◽  
Water Response ◽  
Mixture Suppression ◽  
Principal Axis Factor

1. The responses of 126 neurons in primary gustatory cortices of two rhesus monkeys were recorded during sapid stimulation of the tongue with 18 taste stimuli. Ten of these stimuli were dissolved in distilled water (DW): 1.0 M sucrose (Suc), 0.1 M and 0.03 M sodium chloride (NaCl), 0.003 M hydrochloric acid (HCl), 0.001 M quinine hydrochloride (QHCl), 0.03 M monosodium glutamate (MSG), 0.03 M polycose, 0.3 M glycine, 0.1 M proline, and 0.1 M malic acid. Seven other stimuli were dissolved in 0.03 M MSG; the last stimulus was a mixture of 1.0 M Suc and 0.03 M NaCl. 2. The average spontaneous rate (2.2 +/- 0.2 spikes/s, mean +/- SE) and response to DW (2.5 +/- 0.2) of these 126 neurons was low but within the range previously reported for neurons in primate taste cortex. Suc was the most effective stimulus for 24.1% of the neurons tested followed by NaCl (15.7%), QHCl (14.8%), HCl (11.1%), MSG (10.2%), and other miscellaneous unitary gustatory stimuli (8.3%). Binary taste mixtures were the most effective stimuli for 15.7% of the sample. The net responses (corrected for DW, in spikes/s) for Suc-best (3.3), NaCl-best (4.3), HCl-best (3.4), QHCl-best (2.3), and MSG-best (4.1) were sluggish, but comparable with that reported previously. 3. The response breadth of the 82 neurons that responded best to either Suc, NaCl, HCl, or QHCl measured with the entropy coefficient indicated a moderate response breadth for these neurons (mean = 0.79; range = 0.30-0.98). According to the response criteria adopted in this experiment (water response +/- 1.96 SD), however, 81 of these 82 neurons (98.1%) responded to only one or two of the four basic taste stimuli. The disparity between the entropy- and criterion-based measures of response derive from the nature of the two statistics. Adjustments that would make the entropy statistic less inclusive and the definition of a response according to statistical criteria less exclusive would increase their concordance. 4. Three multivariate statistics (cluster, principal axis factor, and multidimensional analysis) were used to analyze the data. Cluster analysis enabled us to divide the 82 taste neurons into groups on the basis of response similarity. Each of the four largest groups was dominated by neurons that responded best to one of the four basic taste stimuli: Suc, NaCl, QHCl, and HCl (ranked in descending order); the fifth largest cluster contained neurons that responded best to MSG. Principal axis factor analysis demonstrated that 80.8% of the total variance could be accounted for by three factors. Neurons responding best to Suc, NaCl, and QHCl each were closely associated with one of those three factors, but the loadings of the HCl-best neurons were evenly distributed across all three factors. The communality coefficient of these three factors was > 80% for the Suc-, NaCl-, HCl-, and QHCl-best neurons; the MSG-best neurons, by comparison, had very few high loadings on any of these three factors and a correspondingly low communality coefficient of 40.4%, a difference that was statistically significant from the other four groups. Thus the three factors related to Suc-, NaCl-, HCl-, and QHCl-best neurons are not relevant to MSG-best neurons. We used multidimensional analysis to arrange the neurons that responded best to Suc, NaCl, HCl, QHCl, and MSG into five loosely arranged and partially overlapping clusters. A multidimensional space based on stimulus similarity showed that MSG was as different from the four basic taste stimuli as they were from one another. 5. Mixture suppression, a common observation in human psychophysical experiments, was examined at the neurophysiological level by including binary tastants in the stimulus battery. The average response of 19 Suc-best neurons to 1.0 M Suc (4.1 spikes/s) decreased to near 0 when the solvent was changed from DW to either 0.03 M MSG or 0.03 M NaCl. Similar decrements were observed in NaCl- and MSG-best neurons tested with Suc/NaCl mixtures.

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 A Gustotopic Map of Taste Qualities in the Mammalian Brain

Science ◽  
2011 ◽  
Vol 333 (6047) ◽  
pp. 1262-1266 ◽  
Author(s):  
Xiaoke Chen ◽  
Mariano Gabitto ◽  
Yueqing Peng ◽  
Nicholas J. P. Ryba ◽  
Charles S. Zuker
Keyword(s):  
Taste Receptor ◽  
Taste Quality ◽  
Mammalian Brain ◽  
Taste System ◽  
Two Photon ◽  
Central Representation ◽  
The Brain ◽  
Cortical Field ◽  
Taste Coding

The taste system is one of our fundamental senses, responsible for detecting and responding to sweet, bitter, umami, salty, and sour stimuli. In the tongue, the five basic tastes are mediated by separate classes of taste receptor cells each finely tuned to a single taste quality. We explored the logic of taste coding in the brain by examining how sweet, bitter, umami, and salty qualities are represented in the primary taste cortex of mice. We used in vivo two-photon calcium imaging to demonstrate topographic segregation in the functional architecture of the gustatory cortex. Each taste quality is represented in its own separate cortical field, revealing the existence of a gustotopic map in the brain. These results expose the basic logic for the central representation of taste.

scholarly journals Contribution of the TRPV1 channel to salt taste quality in mice as assessed by conditioned taste aversion generalization and chorda tympani nerve responses

2012 ◽  
Vol 303 (11) ◽  
pp. R1195-R1205 ◽  
Author(s):  
Kimberly R. Smith ◽  
Yada Treesukosol ◽  
A. Brennan Paedae ◽  
Robert J. Contreras ◽  
Alan C. Spector
Keyword(s):  
Citric Acid ◽  
Transient Receptor Potential ◽  
Receptor Potential ◽  
Taste Quality ◽  
Transient Receptor Potential Vanilloid ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Trpv1 Channel ◽  
Salt Taste ◽  
Transient Receptor

In rodents, at least two transduction mechanisms are involved in salt taste: 1) the sodium-selective epithelial sodium channel, blocked by topical amiloride administration, and 2) one or more amiloride-insensitive cation-nonselective pathways. Whereas electrophysiological evidence from the chorda tympani nerve (CT) has implicated the transient receptor potential vanilloid-1 (TRPV1) channel as a major component of amiloride-insensitive salt taste transduction, behavioral results have provided only equivocal support. Using a brief-access taste test, we examined generalization profiles of water-deprived C57BL/6J (WT) and TRPV1 knockout (KO) mice conditioned (via LiCl injection) to avoid 100 μM amiloride-prepared 0.25 M NaCl and tested with 0.25 M NaCl, sodium gluconate, KCl, NH4Cl, 6.625 mM citric acid, 0.15 mM quinine, and 0.5 M sucrose. Both LiCl-injected WT and TRPV1 KO groups learned to avoid NaCl+amiloride relative to controls, but their generalization profiles did not differ; LiCl-injected mice avoided the nonsodium salts and quinine suggesting that a TRPV1-independent pathway contributes to the taste quality of the amiloride-insensitive portion of the NaCl signal. Repeating the experiment but doubling all stimulus concentrations revealed a difference in generalization profiles between genotypes. While both LiCl-injected groups avoided the nonsodium salts and quinine, only WT mice avoided the sodium salts and citric acid. CT responses to these stimuli and a concentration series of NaCl and KCl with and without amiloride did not differ between genotypes. Thus, in our study, TRPV1 did not appear to contribute to sodium salt perception based on gustatory signals, at least in the CT, but may have contributed to the oral somatosensory features of sodium.

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.

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