Oregon Research Institute, Eugene, OR, USA.
University of North Carolina, Chapel Hill, NC, USA.
Clin Psychol Rev. 2019 Mar;68:38-53. doi: 10.1016/j.cpr.2018.12.002. Epub 2018 Dec 19.
Multiple theories identify neural vulnerability factors that may increase risk for overeating and weight gain. Early cross-sectional neuroimaging studies were unable to determine whether aberrant neural responsivity was a risk factor for or a consequence of overeating. More recent obesity risk, prospective, repeated-measures, and experimental neuroimaging studies with humans have advanced knowledge of etiologic processes and neural plasticity resulting from overeating. Herein, we review evidence from these more rigorous human neuroimaging studies, in conjunction with behavioral measures reflecting neural function, as well as experiments with animals that investigated neural vulnerability theories for overeating. Findings provide support for the reward surfeit theory that posits that individuals at risk for obesity initially show hyper-responsivity of reward circuitry to high-calorie food tastes, which theoretically drives elevated intake of such foods. However, findings provide little support for the reward deficit theory that postulates that individuals at risk for obesity show an initial hypo-responsivity of reward circuitry that motives overeating. Further, results provide support for the incentive sensitization and dynamic vulnerability theories that propose that overconsumption of high-calorie foods results in increased reward and attention region responsivity to cues that are associated with hedonic reward from intake of these high-calorie foods via conditioning, as well as a simultaneous decrease in reward region responsivity to high-calorie food tastes. However, there is little evidence that this induced reduction in reward region response to high-calorie food tastes drives an escalation in overeating. Finally, results provide support for the theory that an initial deficit in inhibitory control and a bias for immediate reward contribute to overconsumption of high-calorie foods. Findings imply that interventions that reduce reward and attention region responsivity to food cues and increase inhibitory control should reduce overeating and excessive weight gain, an intervention theory that is receiving support in randomized trials.
多种理论确定了可能增加暴饮暴食和体重增加风险的神经脆弱性因素。早期的横断面神经影像学研究无法确定异常的神经反应是暴饮暴食的风险因素还是后果。最近的肥胖风险、前瞻性、重复测量和人类实验神经影像学研究提高了对暴饮暴食引起的发病机制和神经可塑性的认识。在此，我们回顾了这些更严格的人类神经影像学研究的证据，以及反映神经功能的行为测量结果，以及用动物进行的研究，这些研究调查了暴饮暴食的神经脆弱性理论。研究结果支持了奖励过剩理论，该理论认为，肥胖风险个体最初表现出对高热量食物味道的奖励回路过度反应，这从理论上推动了对这些食物的摄入量增加。然而，研究结果几乎没有支持奖励不足理论，该理论假设肥胖风险个体的奖励回路最初表现出低反应性，这促使过度进食。此外，结果还支持激励敏感和动态脆弱性理论，该理论认为，过度食用高热量食物会导致奖励和注意力区域对与摄入这些高热量食物所带来的愉悦奖励相关的线索的反应性增加，同时对高热量食物味道的奖励区域反应性降低。然而，几乎没有证据表明这种对高热量食物味道的奖励区域反应的诱导性降低会导致暴饮暴食的加剧。最后，结果支持这样一种理论，即最初的抑制控制缺陷和对即时奖励的偏好导致了对高热量食物的过度消费。研究结果表明，减少食物线索的奖励和注意力区域反应性并增加抑制控制的干预措施应该可以减少暴饮暴食和过度体重增加，这一干预理论正在随机试验中得到支持。
