Obese subjects show enhanced brain responses in motivation and reward neurocircuitry encompassing sensory and somatic integration-interception, motivation-reward (striatal), emotion, and memory processes, which attenuate frontal region activation during food cues. Bariatric surgery (BS) is the only reliable treatment for morbid obesity. Unfortunately, it is unknown how BS affects neurocircuitry after weight loss. We aimed to examine effects of BS on the basal activity of brain areas involved in reward and motivation processing, emotion, memory, and gut-brain interaction. We combined resting-state fMRI with amplitude of low-frequency fluctuation (ALFF) and Granger causality analysis (GCA) to assess interactions between regions within the frontal-mesolimbic circuitry in 16 obese subjects (OB) and 22 normal-weight (NW) subjects. The OB group was studied at baseline and 1 month post BS. Comparisons between OB and NW, and pre-and post BS showed significant differences in ALFF in areas involved in drive (caudate, orbitofrontal cortex (OFC)), arousal (thalamus), and conditioning/memory (amygdala, hippocampus) (P < 0.05, FDR correction). GCA revealed that in the OB group, the OFC had greater connectivity to limbic regions (amygdala, hippocampus, and medial thalamus) and the caudate. Post BS, the connectivity of the OFC to limbic regions decreased, whereas the connectivity from the amygdala and hippocampus to the caudate and thalamus was enhanced, particularly in subjects with lower body mass index (BMI). OFC activation in the OB group was associated with BMI prior to surgery, and changes in OFC post surgery were associated with alterations in BMI. Overall, the functional connectivity of the OFC was significantly decreased. As it is important for salience attribution and connected to limbic brain regions involved with emotional reactivity and conditioning after BS, its significant association with BMI changes indicates the contribution of OFC changes to the improved control of eating behavior after surgery.

肥胖受试者在动机和奖励神经回路中表现出增强的大脑反应，包括感觉和躯体整合-拦截，动机-奖励（纹状体），情绪和记忆过程，从而减弱了食物提示期间额叶区域的激活。减肥手术（BS）是病态肥胖症的唯一可靠治疗方法。不幸的是，尚不清楚体重减轻后BS如何影响神经回路。我们旨在检查BS对参与奖励和动机处理，情感，记忆和肠脑相互作用的大脑区域基础活动的影响。我们将静止状态功能磁共振成像与低频波动幅度（ALFF）和格兰杰因果关系分析（GCA）相结合，以评估16名肥胖受试者（OB）和22名体重正常（NW）受试者的额中膜回路内区域之间的相互作用。在基线时和BS后1个月对OB组进行了研究。OB和NW以及BS前后的比较表明，在与驱动有关的区域（尾状，眶额皮质（OFC）），觉醒（丘脑）和调节/记忆（杏仁核，海马体）的ALFF有显着差异（P <0.05 ，FDR校正）。GCA显示，在OB组中，OFC与边缘区域（杏仁核，海马体和内侧丘脑）和尾状体的连接性更高。BS后，OFC与边缘区的连通性降低，而杏仁核和海马体与尾状和丘脑的连通性增强，特别是在体重指数（BMI）较低的受试者中。OB组的OFC激活与手术前的BMI有关，而手术后OFC的变化与BMI的改变有关。总体，OFC的功能连接性显着降低。由于它对于显着性归因很重要，并且与BS后涉及情绪反应和调节的边缘脑区域有关，因此它与BMI变化的显着关联表明，OFC变化对改善手术后饮食行为的控制作用。