Localized gustation area in the human brain cortex

Abstract

INTRODUCTION: There have been controversial issue that how we perceive taste in the brain cortex. Recent developments in functional magnetic resonance imaging (fMRI) have provided the possibility to study this system in vivo, and by this technique, insular cortex have been shown to be activated by taste. But there have been few studies to compare the topography of activities elicited by different taste stimuli. OBJECTIVES: The aim of this study is to investigate whether there are neural representations of perceiving each basic taste solutions in the human primary taste cortex. MATERIALS AND METHODS: In order to conduct this experiment precisely, we developed an original taste solution delivery system. Healthy volunteers (ten males and ten females, 19-29 yrs of age) participated in this study, and all images were acquired with a 3.0-T MRI. Umami (0.1M Monosodium L-glutamate and 0.005M inosine monophosphate), salty (0.1M sodium chloride) and sweet (0.5M sucrose) were used as taste solutions and tasteless artificial saliva (using the main ionic components of saliva; 25 mM KCl plus 2.5 mM NaHCO3) as the control. The Human Experimentation Committee of Kyushu University approved all experimental procedures. RESULTS: The areas activated by all taste solutions were located on the putative human primary taste cortex (FWE-corrected P < 0.05). The all activated areas showed some different representation with overlapping each other. DISCUSSION AND CONCLUSION: Activated areas induced by all taste stimuli were well confined in the human primary taste cortex, which suggested the perception of all tastes stimulation occurs in similar way.