Image Sciences Institute, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands.
Rowett Institute, University of Aberdeen, Foresterhill Road, AB25 2ZD Scotland, United Kingdom.
Neuroimage. 2018 May 1;171:246-255. doi: 10.1016/j.neuroimage.2018.01.012. Epub 2018 Jan 12.
The abundant exposure to food cues in our environment is one of the main drivers of overconsumption. Food evaluation is important for the regulation of food intake by the brain and it's interaction with hunger state. Children are especially susceptible to food cues. Understanding the mechanisms behind this regulation in healthy individuals across the life span can help to elucidate the mechanisms underlying overconsumption and aid the development of future obesity prevention strategies. Few functional neuroimaging studies have been done in children and elderly. Furthermore, it is unknown how hunger state affects neural food cue reactivity in these groups, since this has not been examined consistently. We examined the effects of hunger state and age on the brain responses to low- and high calorie foods. On two mornings, 122 participants (17 children; 38 teens; 36 adults; 31 elderly) performed a food image viewing task while being scanned using fMRI, either fasted or sated. Hunger induced greater activation during high versus low calorie food image viewing than satiety in the bilateral dorsomedial (dmPFC) and in the right dorsolateral prefrontal cortex (dlPFC) across all age groups. There was no significant main effect of age group on high versus low calorie food image viewing and no interaction between age group and hunger state. The greater activation of the dlPFC across all age groups during high calorie food image viewing in a fasted state might reflect increased inhibitory control in response to these foods. This may underlie the ability to resist overconsumption of high calorie foods. Furthermore, increased medial prefrontal cortex activation during hunger might reflect increased reward value of high calorie foods, which declines with satiation. Further studies are needed to better understand these results. Notably, overweight and obese individuals should be included to examine whether these responses are altered by weight status across the life span.
在我们的环境中，大量接触食物线索是导致过度消费的主要驱动因素之一。食物评估对于大脑调节食物摄入及其与饥饿状态的相互作用非常重要。儿童尤其容易受到食物线索的影响。了解健康个体在整个生命周期中这种调节的机制可以帮助阐明过度消费的机制，并有助于制定未来的肥胖预防策略。在儿童和老年人中进行的功能性神经影像学研究很少。此外，由于尚未一致检查，因此尚不清楚饥饿状态如何影响这些群体的神经食物线索反应。我们研究了饥饿状态和年龄对大脑对低热量和高热量食物反应的影响。在两天早上，122 名参与者（17 名儿童；38 名青少年；36 名成年人；31 名老年人）在进行 fMRI 扫描时，分别处于禁食或饱腹状态，执行了一项食物图像观看任务。与饱腹感相比，饥饿状态下大脑在观看高热量与低热量食物图像时会产生更大的激活，这种激活存在于双侧背内侧前额叶皮质（dmPFC）和右侧背外侧前额叶皮质（dlPFC）中，并且在所有年龄组中都是如此。在观看高热量与低热量食物图像时，年龄组对大脑的激活没有显著的主要影响，而且年龄组与饥饿状态之间也没有相互作用。在禁食状态下，所有年龄组在观看高热量食物图像时 dlPFC 的激活更大，这可能反映了对这些食物的抑制控制增强。这可能是抵抗过度消费高热量食物的能力的基础。此外，在饥饿状态下，内侧前额叶皮质的激活增加可能反映了高热量食物的奖励价值增加，而这种价值会随着饱腹感的增加而降低。需要进一步的研究来更好地理解这些结果。值得注意的是，应该纳入超重和肥胖个体，以检查这些反应是否会因整个生命周期中的体重状态而改变。
