Fig 1.
Solutions administration protocol.
Taste event consisted of the delivery of 5ml of one solution over 2 sec (2,5 ml/sec injection speed) announced by an auditory cue and followed by a gustatory period of 10 sec. Another auditory cue announced the swallowing of the solution (3 sec) and was followed by a rest period of 15 seconds before the administration of rinse water with the same modality.
Table 1.
Scheme of alternation among tastes.
Fig 2.
Results of the VAS questionnaire analysis.
The average taste perception is reported for all tastes with the significant differences between them at ANOVA (p<0.05).
Table 2.
Main effect of tastes in the right insular cortex.
Fig 3.
Map of the main effects of tastes in the right insular cortex.
Color coded clusters of the within group Random Effect analysis for the different tastants overlapped to a high resolution T1 image after the inclusion of a mask of the right insular cortex (p<0.05 FWE corrected at cluster level). Evidence of a spatial distribution of the six principal tastes is clearly shown even with the overlap of some tastants.
Fig 4.
Cortical surface representation of right insular activation of the standardized five basic tastes and CO2.
In these maps, each vertex of the CBA alignment (top row) is colored with the taste that has the biggest response averaged across all subjects and its color intensity indicate how strong is the taste prevalence (a 100% value indicate that the taste prevalence is twice the second taste represented on that vertex). In the bottom row the prevalence map of two representative subjects are reported overlapped to their original anatomy.
Fig 5.
Cortical surface representation of right insular activation of the standardized five basic tastes without CO2.
In these maps, each vertex of the CBA alignment is colored with the taste that has the biggest response averaged across all subjects and its color intensity indicate how strong is the taste prevalence (a 100% value indicate that the taste prevalence is twice the second taste represented on that vertex).
Fig 6.
Bar graphs of the similarity of each individual subject to each and any specific tastant.
In the map results of the correlation analysis of the prevalence maps of each subject vs mean prevalence maps (Spearman correlation coefficient p<0.0001) is depicted in the first bar while the other bars show the correlation of the beta maps of all the subjects for each tastant (Pearson correlation coefficient p<0.0001).