HOW EMOTION REGULATION AFFECTS DIETARY CHOICE BY MODULATING VALUE SIGNALS IN THE VMPFC

Introduction

Many people eat specific foods to distract themselves from, or cope with, negative affect such as stress, anxiety, or fear, (1,2,3). Most such “comfort” foods are indulgent, sweet, carbohydrate- and fat-rich and therefore provide immediate satisfaction. Negative emotions can also increase the salience of immediate, concrete goals thereby increasing preference for indulgent foods (4). These dietary choices are difficult to control and can have severe consequences for people’s health. One intriguing countermeasure, however, could be to improve one’s emotion regulation. In this study, we tested whether down-regulating emotional responses to negative images subsequentially also leads to less unhealthy food choices. We further investigated how emotion regulation interacts with the brain’s valuation and decision-making circuitry during decision-making using functional magnetic resonance imaging (fMRI).

Methods

We tested 35 healthy participants (age=23.17±3.44 yrs; 29 female; fasted for 7h). An event-related design was used (Figure1) incorporating a standard emotion regulation task (5) with 2 conditions: a) Look (control condition): participants were presented with negative images and allowed themselves to experience any emotional responses without regulating; b) Decrease: participants reduced the intensity of the negative emotion by distancing themselves from the image. On each trial the emotion regulation phase was followed by a food choice (6). Participants were shown pictures of a food item and rated their preference for eating the food after the experiment. Food items were also rated on taste and healthiness before the experiment. We acquired 5 runs and 140 trials using a standard MRI sequence (3.0 T Magnetom TrioTim scanner).

Results

Participants felt less negative after the down-regulation of emotions compared control (t(34)=5.99, p<0.001). Using a repeated-measures ANOVA for percentage “yes” choices with the factors health (unhealthy/healthy) and regulation (decrease/control), we found a significant main effect for health (F(1,34)=51.32, p<0.001) and regulation (F(1,34)=13.08, p<0.001) as well as a significant interaction effect (F(1,34)=23.66, p<0.001). Participants chose healthy foods more often than unhealthy foods in both the control condition (t(34)=5.70, p<0.001) and the emotion regulation condition (t(34)=8.44, p<0.001). Crucially, however, this preference for healthy food was increased in the emotion regulation as compared to the control condition (t(34)=4.74, p<0.001).

At the neuronal level, using a parametric analysis at the time of decision making, we found that the ventromedial prefrontal cortex (vmPFC) correlated with participants’ preference ratings (x=6, y=29, z=11; k=536; p<0.001 FWE corr.), suggesting food value processing in this region, and to some extent with health ratings (x=-9, y=38, z=-1, k=50, p=0.02 uncorr.) (Figure2a). Subsequent ROI analyses in this vmPFC cluster also showed a significant main effect for emotion regulation (F(31)=7.98, p<0.01). Signal changes were significantly less decreased in the emotion regulation condition compared to the control condition (t(31)= 2.82, p<0.01) (Figure2b).

Conclusions

We found that while our participants preferred healthy foods overall, the regulation of negative emotions led to a reduction of preferences for indulgent foods, similar to effects reported in studies that showed improved dietary choices after directing attention to the healthiness of foods (6,7). Emotion regulation most likely counteracted the effect of negative emotions, buffering the shift to comfort foods that might be triggered by negative emotions. This interpretation is supported by the finding that in vmPFC, which reflected preference (6), the overall signal strength was further modulated by emotion regulation. This suggests that the modulatory effect of emotion regulation on choosing less comfort food might be moderated, or potentially implemented, by vmPFC.

References

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