Associations of Gray Matter Volume and Perceived Intensity of Bitter Taste: a Voxel-Based Morphometry Study

Abstract

Two recent brain morphological studies reported inconsistent results on the neuroanatomical correlates of taste intensity rating among healthy populations. The current study re-visited this issue with a large and more homogeneous sample size. It was hypothesized that the orbitofrontal cortex, the sole region commonly reported by the two studies together with olfactory studies, had its gray matter volume (GMV) correlated to taste intensity rating. The open data from the Human Connectome Project (HCP, S1200 release dataset) was used. Data from 213 subjects were analyzed. They were aged 22–25, completed 3-Tesla structural brain scan, and were asked to taste a bitter solution (0.001 M quinine) and rate the perceived intensity with a general Labelled Magnitude Scale. The age-adjusted taste intensity rating was used for the current analysis. Voxel-based morphometry (VBM) using CAT12 toolbox implemented in SPM12 was conducted with the default procedures and settings. Whole brain analysis was performed at a threshold of cluster p < 0.05, familywise error corrected (FWE), with a primary cluster-forming threshold of uncorrected voxel p < 0.001. Voxel-wise GMV was significantly correlated to taste intensity rating in the right angular gyrus. OFC was insignificant even with a more liberal threshold of uncorrected voxel p < 0.001. The current results were again different from previously published reports. This might be due to heterogeneous population, data processing, and analytical methods. At the current stage, the morphometric finding from brain imaging is not yet a simple and reliable biomarker for assessing taste intensity perception.