Presentation Details
Elucidating a Potential Detection Mechanism for High-Viscosity Solutions in the Oral Cavity

Brittany L.Miles, Christopher T.Simons.

The Ohio State University, Columbus, OH, USA


Multiple modelling studies have suggested that perception of high-viscosity (η>3000cP) solutions is linked to the directional deformation of filiform papillae, although this has not been tested in humans. Thus, this study sought to further characterize the detection mechanism underpinning the perception of these solutions via psychophysical testing. We hypothesized that discrimination ability of high-viscosity solutions would be linked to filiform papillary attributes. Just-noticeable difference (JNDs) thresholds were determined for participants (n=45) using the forced-choice staircase method for viscosities of glycerin/water/carboxymethyl cellulose solutions (η=4798-12260cP). Participants evaluated solutions by pressing them against the hard palate while wearing retainers made of moldable plastic allowing for isolation of the tongue. Additionally, optical profiling was used to characterize papillary structures in tongue biopsies from the dorsal medial tongue. Papillary attributes were then related to psychophysical performance using causal analysis. Perceptual data significantly correlated to multiple filiform papillary attributes including average papillary length (R2=0.272, p<0.001) and average papillary density (R2=0.178, p=0.003). Moreover, causal analysis indicated that variation in these attributes alone explained the variation in subjects’ JND (p<0.001). This study provides insight into the tongue’s role in the perception of high-viscosity solutions. While some previous works propose filiform papillae may help discriminate varying viscosities, other studies consider the structures to be primarily vestigial. The clear association delineated here underpins the likely relevance of filiform papillae in viscosity discrimination and may indicate relevance for other texture precepts.

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