Predicting Perceived Hedonic Ratings through Facial Expressions of Different Drinks.

Previous studies have established the utility of facial expressions as an objective assessment approach for determining the hedonics (overall pleasure) of food and beverages. This study endeavors to validate the conclusions drawn from preceding research, illustrating that facial expressions prompted by tastants possess the capacity to forecast the perceived hedonic ratings of these tastants. Facial expressions of 29 female participants, aged 18-55 years, were captured using a digital camera during their consumption of diverse concentrations of solutions representative of five basic tastes.

Correction: Analysis of facial expressions in response to basic taste stimuli using artificial intelligence to predict perceived hedonic ratings.

[This corrects the article DOI: 10.1371/journal.pone.

Analysis of facial expressions in response to basic taste stimuli using artificial intelligence to predict perceived hedonic ratings.

Taste stimuli can induce a variety of physiological reactions depending on the quality and/or hedonics (overall pleasure) of tastants, for which objective methods have long been desired. In this study, we used artificial intelligence (AI) technology to analyze facial expressions with the aim of assessing its utility as an objective method for the evaluation of food and beverage hedonics compared with conventional subjective (perceived) evaluation methods. The face of each participant (10 females; age range, 21-22 years) was photographed using a smartphone camera a few seconds after drinking 10 different solutions containing five basic tastes with different hedonic tones.

Activity of frontal pole cortex reflecting hedonic tone of food and drink: fNIRS study in humans.

Cognitive and hedonic aspects of taste have been studied using different neuroimaging techniques in humans. However, the methods used are unsuitable for easy monitoring of hedonics induced by intake of foods and beverages. Here we have tried to monitor changes in oxygenated hemoglobin (oxyHb) levels in the anterior prefrontal cortex (aPFC, frontopolar cortex, Brodmann area 10) in response to intake of hedonically different edibles in healthy adults.

Saccharin Taste Conditions Flavor Preference in Weanling Rats.

Innate and learned taste/flavor preferences to chemical stimuli in weanling rats are not fully understood. Our previous study showed that weanling rats could establish conditioned flavor preferences when low, but not high, concentrations of sucrose solutions were used as associative rewarding stimuli. Here, we examined whether 3-week-old rats could acquire flavor learning when the rewarding stimulus was saccharin, a non-nutritive artificial sweetener.

Flavor learning in weanling rats and its retention.

The present study examined whether weanling animals can acquire associative memory for reward and retain it several weeks later. Three-week-old Wistar male rats were trained in a flavor learning task. Half of the rats received unsweetened grape-flavored water on odd-numbered days and sweetened (sucrose) cherry-flavored solution on even-numbered days.

Brain mechanisms of flavor learning.

Once the flavor of the ingested food (conditioned stimulus, CS) is associated with a preferable (e.g., good taste or nutritive satisfaction) or aversive (e.