Merchant Junaid S, Cosme Danielle, Giuliani Nicole R, Dirks Bryce, Berkman Elliot T
Neuroscience and Cognitive Science Program (NACS), Department of Psychology, University of Maryland, College Park, MD, United States.
Annenberg School for Communication, University of Pennsylvania, Philadelphia, PA, United States.
Front Behav Neurosci. 2020 Dec 4;14:578676. doi: 10.3389/fnbeh.2020.578676. eCollection 2020.
Considerable evidence points to a link between body mass index (BMI), eating behavior, and the brain's reward system. However, much of this research focuses on food cue reactivity without examining the subjective valuation process as a potential mechanism driving individual differences in BMI and eating behavior. The current pre-registered study (https://osf.io/n4c95/) examined the relationship between BMI, healthy eating, and subjective valuation of healthy and unhealthy foods in a community sample of individuals with higher BMI who intended to eat more healthily. Particularly, we examined: (1) alterations in neurocognitive measures of subjective valuation related to BMI and healthy eating; (2) differences in the neurocognitive valuation for healthy and unhealthy foods and their relation to BMI and healthy eating; (3) and whether we could conceptually replicate prior findings demonstrating differences in neural reactivity to palatable vs. plain foods. To this end, we scanned 105 participants with BMIs ranging from 23 to 42 using fMRI during a willingness-to-pay task that quantifies trial-by-trial valuation of 30 healthy and 30 unhealthy food items. We measured out of lab eating behavior via the Automated Self-Administered 24 H Dietary Assessment Tool, which allowed us to calculate a Healthy Eating Index (HEI). We found that our sample exhibited robust, positive linear relationships between self-reported value and neural responses in regions previously implicated in studies of subjective value, suggesting an intact valuation system. However, we found no relationship between valuation and BMI nor HEI, with Bayes Factor indicating moderate evidence for a null relationship. Separating the food types revealed that healthy eating, as measured by the HEI, was inversely related to subjective valuation of unhealthy foods. Imaging data further revealed a stronger linkage between valuation of healthy (compared to unhealthy) foods and corresponding response in the ventromedial prefrontal cortex (vmPFC), and that the interaction between healthy and unhealthy food valuation in this region is related to HEI. Finally, our results did not replicate reactivity differences demonstrated in prior work, likely due to differences in the mapping between food healthiness and palatability. Together, our findings point to disruptions in the valuation of unhealthy foods in the vmPFC as a potential mechanism influencing healthy eating.
大量证据表明体重指数（BMI）、饮食行为与大脑奖励系统之间存在联系。然而，这项研究大多聚焦于食物线索反应性，却未将主观评估过程作为驱动BMI和饮食行为个体差异的潜在机制进行考察。当前的预注册研究（https://osf.io/n4c95/）在一个BMI较高且打算更健康饮食的社区样本中，研究了BMI、健康饮食与健康和不健康食物主观评估之间的关系。具体而言，我们考察了：（1）与BMI和健康饮食相关的主观评估神经认知指标的变化；（2）健康和不健康食物的神经认知评估差异及其与BMI和健康饮食的关系；（3）我们是否能够从概念上重复先前的研究结果，即证明对美味食物与普通食物的神经反应存在差异。为此，我们使用功能磁共振成像（fMRI）对105名BMI在23至42之间的参与者进行扫描，扫描过程采用支付意愿任务，该任务对30种健康和30种不健康食物进行逐次试验评估。我们通过自动自我管理的24小时饮食评估工具测量实验室外的饮食行为，借此计算出健康饮食指数（HEI）。我们发现，在先前涉及主观价值研究的区域中，我们的样本在自我报告价值与神经反应之间呈现出稳健的正线性关系，这表明评估系统完好无损。然而，我们发现评估与BMI或HEI之间没有关系，贝叶斯因子表明存在适度证据支持零相关关系。将食物类型分开分析显示，以HEI衡量的健康饮食与不健康食物的主观评估呈负相关。成像数据进一步揭示，健康（与不健康相比）食物的评估与腹内侧前额叶皮层（vmPFC）的相应反应之间存在更强的联系，并且该区域健康和不健康食物评估之间的相互作用与HEI有关。最后，我们的结果未能重复先前研究中显示的反应性差异，这可能是由于食物健康程度与美味程度之间的映射关系存在差异所致。总之，我们的研究结果表明，vmPFC中不健康食物评估的破坏是影响健康饮食的潜在机制。
