It's in the eye of the beholder: selective attention to drink properties during tasting influences brain activation in gustatory and reward regions

Abstract

Statements regarding pleasantness, taste intensity or caloric content on a food label may influence the attention consumers pay to such characteristics during consumption. There is little research on the effects of selective attention on taste perception and associated brain activation in regular drinks. The aim of this study was to investigate the effect of selective attention on hedonics, intensity and caloric content on brain responses during tasting drinks. Using functional MRI brain responses of 27 women were measured while they paid attention to the intensity, pleasantness or caloric content of fruit juice, tomato juice and water. Brain activation during tasting largely overlapped between the three selective attention conditions and was found in the rolandic operculum, insula and overlying frontal operculum, striatum, amygdala, thalamus, anterior cingulate cortex and middle orbitofrontal cortex (OFC). Brain activation was higher during selective attention to taste intensity compared to calories in the right middle OFC and during selective attention to pleasantness compared to intensity in the right putamen, right ACC and bilateral middle insula. Intensity ratings correlated with brain activation during selective attention to taste intensity in the anterior insula and lateral OFC. Our data suggest that not only the anterior insula but also the middle and lateral OFC are involved in evaluating taste intensity. Furthermore, selective attention to pleasantness engaged regions associated with food reward. Overall, our results indicate that selective attention to food properties can alter the activation of gustatory and reward regions. This may underlie effects of food labels on the consumption experience of consumers.

Keywords: Calories; Functional magnetic resonance imaging; Intensity; Pleasantness; Selective attention; Taste.

Fig. 1

Schematic overview of trial structures during a block of the taste-task

Fig. 2

Subjective ratings (mean + SD) on a 5-point scale for intensity during selective attention to intensity, caloric content during selective attention to caloric content and pleasantness during selective attention to pleasantness of a fruit juice (F), tomato juice (T) and water (W), obtained during scanning. Repeated measures ANOVA on average ratings over the three runs, post-hoc t-tests, P < 0.05, LSD-corrected for multiple comparisons. Bars within each condition that have a different letter differ significantly

Fig. 3

Illustration of Brain activation versus rest during selective attention to taste intensity, caloric content and pleasantness (thresholded at P = 0.001, k = 4) and their conjunction (Top, thresholded at T = 8, k = 4). Shown are T-maps in axial sections at MNI z-coordinates −1, 4, 9 and 14). Full details can be found in Supplementary Table 1- 4

Fig. 4

Illustration of differences in brain activation during selective attention to taste intensity (intens), caloric content (cal) and pleasantness (pleas) in the (a) left inferior frontal gyrus (frontal operculum)/left middle insula (peak at MNI: −45, 11, 4), (b) right mid insula (peak at MNI: 45, 2, −2), (c) right anterior cingulate cortex (peak at MNI: 15, 44, 19), (d) right putamen (peak at MNI: 30, −4, −2), and (e) right superior frontal gyrus (mid OFC) (peak at MNI: 15, 62, −5). Shown are average cluster parameter estimates (+SE) for the contrast versus rest, obtained for the clusters showing significant differences between conditions, as assessed with one-sample t-tests on the respective contrasts (P < 0.001, k > 4, see Table 1). Bars having a different letter differ significantly. Ant = anterior, sup = superior, inf = inferior, mid = middle, L = left and R = right

Fig. 5

Scatterplot illustrating the correlation between brain activation during selective attention to taste intensity and subjective intensity ratings in a cluster in the right anterior insula extending into the right inferior frontal gyrus (lateral OFC) (peaks at MNI: 33 17–14 and 33 29–14, see Table 2). Ant = anterior, inf = inferior, lat = lateral and R = right