Effects of a pressure surround on the regional taste detection threshold for sodium chloride

Trial measurement of brain activity underlying olfactory-gustatory synchrony perception using event-related potentials from five female participants

Temporal synchrony between odor and taste plays an important role in flavor perception. When we investigate temporal synchrony between odor and taste, it is necessary to pay attention not only to physical simultaneity of the presentation of olfactory and gustatory stimuli, but also to the perceptual simultaneity between the two stimuli. In this study, we examined short-latency brain activity underlying synchrony perception for olfactory-gustatory combinations. While five female participants performed a simultaneity judgment (SJ) task using soy sauce odor and salt solution, single-channel event-related potentials (ERPs) were recorded at the position of Cz. In each trial, the participant was asked whether olfactory and gustatory stimuli were perceived simultaneously or successively. Based on the judgment responses acquired from participants (i.e., simultaneous or successive), ERP data were classified into two datasets. The means of ERPs from each participant were calculated for each type of judgment response, considering the onset of olfactory or gustatory stimuli (OERPs or GERPs, respectively) as the starting point. The latencies of the P1 component of GERPs were very similar between simultaneous and successive judgment responses, whereas the P1 amplitudes differed significantly. These results indicated that neural activity affecting SJ for an olfactory-gustatory combination is generated during a period of about 130 ms from the onset of gustatory stimulus. Thus, olfactory and gustatory information processing related to flavor perception (more specially, synchrony perception between odor and taste) might be initiated at a relatively early stage of the central pathway.

Single bright light exposure decreases sweet taste threshold in healthy volunteers

INTRODUCTION

Bright light exposure can alter circulating serotonin levels, and alteration of available serotonin by acute selective serotonin reuptake inhibition significantly lowers sweet but not salt taste recognition thresholds. We tested the hypothesis that bright light exposure would increase sweet but not salt taste sensitivity in healthy adults.

METHODS

Fourteen healthy volunteers were exposed to bright (10,000 lux) and dim (<20 lux) light for 30 min each, in counterbalanced order. Measures of taste perception (salt and sweet) and mood were determined at baseline, and before and after each light exposure period.

RESULTS

Recognition thresholds for sucrose were significantly lower after bright but not dim light exposure. Thresholds for salt were unaffected by either condition. There were no significant changes in taste acuity, intensity or pleasantness for both the taste modalities and on visual analogue scales (VASs) for mood, anxiety, sleepiness and alertness, under either light condition.

CONCLUSION

Brief bright light exposure reduces sweet but not salt taste recognition thresholds in healthy humans.

Revisão: metodologias para análise da sensibilidade gustativa ao sal

A avaliação da sensibilidade gustativa ao sal é utilizada na área da saúde, bem como em análise sensorial aplicada à Ciência e Tecnologia de Alimentos, para avaliar o paladar e identificar ageusia e hipoageusia de diversas origens; notavelmente, identifica os indivíduos que apresentam risco ou consumo excessivo de sal. A adoção de um método acurado e reprodutível para avaliação do limiar gustativo ao sal permite seu uso de forma ampliada. Esta revisão integrativa tem como objetivo descrever as metodologias empregadas para avaliar o limiar de detecção e reconhecimento do cloreto de sódio. Foram utilizadas as bases de dados CINAHAL, LILACS e MEDLINE, e as palavras-chave taste threshold, sodium chloride e salt. Foram localizados 27 artigos de 1985 a 2009 e, nestes, empregados 29 testes de análise do limiar. A maioria dos artigos utilizou o estímulo da boca toda (75,9%), seguida da aplicação tópica na língua (24,1%), aplicação da solução em partes da língua (10,3%), eletrogustometria (6,4%), disco impregnado (3,4%) e aplicação de vácuo (3,4%). Houve grande variação nos procedimentos metodológicos e, em alguns, ausência de informações importantes. Os artigos não apresentam cálculo do tamanho amostral e os critérios de seleção dos julgadores foram também variados. Assim, existe uma dificuldade para a reprodutibilidade e as comparações dos artigos. Avaliações comparativas entre os diferentes métodos de avaliação do limiar gustativo ao cloreto de sódio quanto à sua reprodutibilidade podem trazer subsídios importantes para a escolha do método mais adequado a ser empregado em pesquisa e na prática clínica.