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

Yuji Minematsu,Kayoko Ueji,Takashi Yamamoto

doi:10.1038/s41598-018-34690-3

Abstract

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. When subjects tasted sweet and bitter solutions freely without any particular instruction, cortical activation varied greatly among subjects and between the two stimuli, and no consistent results were obtained. Subjects then ate or drank preferred (hedonically positive) and disliked (hedonically negative) edibles. Although these stimuli differed among subjects, hedonically positive stimuli decreased oxyHb, whereas hedonically negative stimuli increased oxyHb, particularly in the ventral aPFC. When subjects tasted 4 kinds of jellies with different flavors and evaluated the degree of pleasantness, oxyHb level in the ventral region correlated negatively with pleasantness score. These results revealed that pleasant and unpleasant edibles tended to elicit decreased and increased oxyHb levels, respectively, within the ventral aPFC, suggesting that monitoring of oxyHb in this region may prove useful for objective evaluation of pleasantness of food and drink.

Highlights

Food companies evaluate the palatability and acceptability of new foods and beverages mainly using a variety of sensory tests
The precise functions of the aPFC still need to be elucidated, the present study explored the possible representation of affective reactions related to hedonic evaluations of food and drink
The deoxygenated hemoglobin level was relatively stable throughout the stimulation period

Summary

Introduction

Food companies evaluate the palatability and acceptability of new foods and beverages mainly using a variety of sensory tests. A number of studies have been published on the location and magnitude of brain activity in response to the taste and flavor of different edibles with positive and negative hedonics Through such studies, qualitative and quantitative aspects of taste are generally accepted to be processed in the operculum and insula, representing the primary cortical gustatory area[1,2,3,4,5], while food reward value and subjective pleasantness are processed in the orbitofrontal cortex (OFC), as the secondary cortical gustatory area[6,7,8,9], along with the lateral prefrontal cortex (LPFC)[10,11,12,13,14], anterior cingulate cortex (ACC), amygdala, reward system and hypothalamus[7]. The precise functions of the aPFC still need to be elucidated, the present study explored the possible representation of affective reactions related to hedonic evaluations of food and drink

Methods

Results

Conclusion