奖赏敏感性和抑制控制对暴食的影响:行为和脑成像证据

发布时间：2018-05-13 09:19

  本文选题：暴食症 + 冲动性　； 参考：《西南大学》2016年博士论文

【摘要】：暴食(Binge eating,BE)通常是指在短时间内进食大量食物,并伴随失去控制的感觉。每周发生一次暴食并持续三个月就满足了暴食症(Binge eating disorder,BED)的诊断标准。暴食症通常是指反复的暴食发作,并伴随失去控制、痛苦的感觉,但与贪食症(Bulimia nervosa,BN)不同,暴食症不会发生为维持体重的不恰当补偿行为,如过度节食或运动等。根据最近的研究,有许多因素影响暴食症的发作和维持,主要包括应激,负性情绪,冲动性,身体不满意,节食,人际关系以及父母的喂养方式。一般认为冲动性是暴食和暴食症发生和维持的主要因素。冲动性由两个因素构成:奖赏敏感性和自发冲动行为。前者力求欲望或奖赏刺激(如食物线索),而后者不计后果的放纵行动。刺激敏化理论解释了暴食行为形成和持续的原因。易感个体反复暴露于奖赏刺激会加剧奖赏反应。因此暴露于奖赏刺激会激活大脑的奖赏系统,导致个体生理唤醒及渴求的感觉,特别是在抑制控制失败的时候,最终会导致暴食发作。关于暴食症对食物线索的奖赏敏感性和抑制控制缺陷研究并不全面。在奖赏敏感性方面的研究还没有确定暴食是否与特定类型食物(如高热量食物与低热量食物)的反应增加有关。此外,已有研究主要关注的是肥胖或超重的暴食症群体,但是有很大一部分暴食个体在正常体重范围内,特别是在亚洲国家,这里集中了世界上的大部分人口。基于过去的研究范式,关于暴食抑制控制缺陷的研究结果并不一致,一些研究发现这种缺陷是普遍的,而另外一些研究却认为这种缺陷是针对食物线索的,还有一些研究并没有发现暴食个体具有抑制控制方面的缺陷。已经有研究开始关注暴食的神经机制。在暴食群体中,对食物线索的奖赏和抑制神经反应的重要性并不清楚,如目前还没有研究使用低频振幅(the amplitude of low frequency fluctuations,ALFF)来评估暴食组和控制组在奖赏和抑制控制区域的大脑活动上的差异。此外,虽然应激和负性情绪常常促进暴食发作,但是在这些条件下的进食增加是否是由于对外界食物的奖赏反应增加还是由于抑制控制的减少,原因并不清楚。为了解决这些问题,本论文设计了六个研究来考察奖赏敏感性和抑制控制对正常体重的暴食个体行为和神经反应的影响。研究1和研究2使用不同的实验室范式考察暴食个体的行为反应。在研究1中,主要考察了有暴食行为的女性(33人)与控制组女性(31人)的注意脱离偏向。被试完成一个空间线索任务,此任务中她们首先需要观察高热量食物、低热量食物或中性图片,然后快速判断随后目标(一个圆点)出现的位置。对两组被试来说,在有效线索试次(即目标出现在线索的同侧)中,被试的反应时要显著长于无效线索试次(即目标出现在线索的对侧),这反应了抑制返回效应(inhibition of return effect,IOR)。然而,在反应时中也发现,与控制组相比,有暴食行为的女性对高热量食物表现出更强的脱离困难,而在其他类型刺激上却没有这种差异。对高热量食物的注意脱离困难意味着对这类线索的奖赏敏感性增加,这也增加了暴食行为发生的风险。在研究2中,有暴食行为的正常体重女性(31人)和无暴食行为的女性(31人)在禁食12小时候后,完成一个与食物有关的Go/No-Go任务。该任务刺激包含高热量食物、低热量食物和中性图片。任务完成后,被试要在实验室自由进食食物(巧克力和面包)。有暴食行为的女性报告了更高的特质冲动,更多的进食食物。虽然在整体的虚报(当“No-Go”刺激出现时被试错误按键)上差异不显著,但是暴食个体对高热量食物线索反应比控制组更快,同时在正确率上,暴食组对高热量食物线索反应的正确率要高于低热量食物,而控制组不存在这种差异。此外,被试在“Go”试次上的反应时与任务完成后的进食量呈负相关,而虚报率与进食量呈正相关。总之,暴食个体对食物线索存在奖赏敏感性,而抑制控制可能没有受损。在研究3中,考察了暴食症个体和控制组在暴食症状、奖赏敏感性和抑制控制、对食物图片的大脑反应以及进食量之间的关系。在f MRI实验过程中,19名符合暴食症诊断标准的被试和27名控制组被试观看食物图片,包括高热量食物、低热量食物和中性图片。随后被试完成一些列问卷,包括暴食行为,食物渴望、普通奖赏敏感性和行为抑制、情绪状态,然后进食零食。研究结果发现,与控制组相比,暴食症个体报告了更多的暴食行为、进食失控、食物渴望以及边缘显著的奖赏敏感性和抑制控制。扫描结束后,暴食症组个体也进食了更多的巧克力。在观看食物图片时,暴食症个体的额下回、额中回和颞中回有较多的激活,而楔前叶、扣带回有较少的激活。巧克力的消耗则与额中回、楔前叶的激活呈显著负相关。总之,这些结果显示,对暴食症个体而言,冲动控制的特定脑区在对外界食物食物刺激和进食发挥中重要作用。在研究4中,用Go/No-Go任务考察了抑制反应的相关神经活动,在这个任务中,“No-Go”或抑制控制测试由高热量食物图片构成。基于结构性面谈,17名女性满足DSM-V中暴食症的诊断标准,17名没有进食障碍的女性作为控制组。所有被试完成Go/No-Go任务并进行f MRI扫描,然后完成相关问卷。在问卷测量上,暴食症个体报告了高水平的冲动性、进食失控,更多的节食和对体型、体重、进食的关注。同时暴食症个体也有较高的抑郁,焦虑和压力。在Go/No-Go任务,暴食症个体有较多的虚报,反应了其抑制控制的缺陷。在高热量食物图片线索的“No-Go”反应中,暴食症个体在脑岛上有较多的激活。脑岛包含初级味觉皮层,也涉及对食物的预期和进食。同时暴食症个体在中央前回和中央后回也有更多的激活。这些区域涉及味知觉加工,同时个体暴露于食物线索时,这些区域也会激活。这些结果显示,暴食症个体可能由于对高热量食物线索的奖赏敏感性增加导致较差的抑制控制,在抑制反应的时候需要较多的控制力。在研究5中,采用静息态功能磁共振探讨了研究4中暴食症个体和控制组自发脑信号的低频振幅。研究结果发现暴食症个体在楔前叶、额中回、额上回有较高的活动,而在颞中回有较低的活动。进一步分析发现在暴食症个体上,身体质量指数(BMI)与眶额叶皮层(orbitofrontal cortex,OFC)的活动成正相关,而冲动性特质分数与背外侧前额叶皮层(dorsal-lateral prefrontal cortex,DLPFC)的活动成正相关。同时眶额叶皮层与背外侧前额叶皮层的功能连接要显著大于控制组。这些结果显示,眶额叶皮层和背外侧前额叶皮层功能连接的增加在暴食症的病理生理中发挥着重要的作用。在研究6中,主要探讨了暴食症个体和控制组对食物图片的脑活动及其随后的进食行为中,急性应激对其的影响。19名符合暴食症诊断标准的被试和控制组被随机分配到应激组(完成冷压痛任务,并给予负性反馈)和中性组(完成非疼痛感觉辨别任务并给予积极反馈)。随后他们观看食物图片和中性图片,并进行功能磁共振扫描。完成扫描后,被试填写问卷并进食零食。研究结果发现,暴食症个体在应激条件下更喜欢高热量食物,同时在海马上有较少的激活。应激条件下的暴食症个体进食了更多的巧克力。更重要的是,在所有被试中,观看高热量食物图片时海马的激活与进食巧克力的数量成负相关。本研究的结果显示负性急性应激可以减少控制区域的激活,而这些区域在暴食症个体中与食物线索和进食有关。综上有以下几个发现:有暴食行为的女性对高热量食物表现出高水平奖赏敏感性,且抑制控制能力越差,进食量越多;在暴食症个体对食物线索反应和进食中,奖赏和抑制控制的特定脑区发挥着重要的作用;奖赏区域(OFC)和抑制控制区域(DLPFC)功能连接的增加可能导致了暴食症的发生和维持;负性应激减少抑制控制区域的活动,可能会导致进食失控。本论文的发现为暴食症的刺激敏化理论提供了证据。
[Abstract]:Binge eating (BE) usually refers to eating a large amount of food in a short period of time and with the sense of loss of control. A binge eating and lasting three months a week meets the diagnostic criteria for Binge eating disorder (BED). Unlike Bulimia nervosa (BN), BH does not occur as an improper compensation behavior for maintaining weight, such as overeating or exercise. According to recent studies, many factors affect the attack and maintenance of binge, including stress, negative emotion, impulsiveness, body dissatisfaction, dieting, interpersonal relationships, and parental feeding. Impulsivity is the main factor in the occurrence and maintenance of binge eating and overeating. Impulsivity consists of two factors: reward sensitivity and spontaneous impulsiveness. The former strives for desire or reward stimulation (such as food clues), and the latter does not count the consequences of the indulgence. The repeated exposure to reward stimulation exacerbates the reward response. Therefore, exposure to the reward stimulation activates the reward system of the brain that causes the feeling of individual physiological arousal and craving, especially during the inhibition of control failure. Not comprehensive. Research on the reward sensitivity has not yet been determined whether or not the response to specific types of food (such as high calorie food and low calorie food) is increased. In addition, research has focused mainly on obese or overweight binge eating groups, but a large portion of the overeating individuals are within the normal weight range, especially in subtropical regions. The continent, which concentrates most of the population in the world, is based on past research paradigms, and some studies have found that the defects are common, while some studies have found that the defects are common to food clues, and some studies have not found a binge eating individual. There has been a lack of control. Research has begun to focus on the nervous mechanism of overeating. In a population, the importance of reward for food clues and the inhibition of neural responses is not clear, for example, the the amplitude of low frequency fluctuations (ALFF) has not been studied to evaluate the bulge group and the control group at the prize. In addition, although stress and negative emotions often promote binge eating, it is not clear whether the increase in food intake in these conditions is due to the increase in the reward response to the outside food or the decrease in control. Six studies were conducted to examine the effects of reward sensitivity and inhibition control on individual behavior and neural responses to normal weight loss. Study 1 and Study 2 used different laboratory paradigms to examine the behavioral responses of individuals with binge eating. In the study 1, the main investigation was that women (33) who had binge eating behavior were divorced from the control group (31). The subjects completed a space clue task in which they first needed to observe the high calorie food, low calorie food or neutral pictures, and then quickly judge the position of the subsequent target (a round point). For the two groups, the test was significantly longer than no one in the effective clue test (that is, on the same side of the online cable). Inhibition of return effect (IOR) was reacted to the effect of an effective clue (i.e. the target appears on the opposite side of the online cable). However, in response to the control group, women with binge eating behavior showed greater difficulty in disengagement from high calorie foods, but there was no difference in other types of stimulation. The disengagement of food attention meant an increase in the reward sensitivity of these clues, which also increased the risk of overeating. In Study 2, the normal weight women (31) with binge eating behavior and women without eating behavior (31) finished a food related Go/No-Go task after the fasting. The task was stimulated. Including high calorie food, low calorie food and neutral pictures. After the task was completed, the subjects were free to eat food (chocolate and bread) in the laboratory. Women who had bun reported higher idiosyncratic impulses and more food. Although the difference was not significant in the overall false report (when the "No-Go" stimulus appeared). However, the rate of cue response to high calorie food was faster than that of the control group. At the correct rate, the correct rate of high calorie food cue reaction was higher than that of low calorie food at the correct rate, while the control group did not have this difference. In addition, the response of the subjects on the "Go" trial was negatively correlated with the amount of food after the task was completed, and the false rate rate was also reported. In the study 3, the relationship between binge eating symptoms, reward sensitivity and inhibitory control, the relationship between the brain response to food pictures and the amount of food was examined in the study 3, 19 in the f MRI experiment. Participants and 27 control groups were tested for food pictures, including high calorie food, low calorie food, and neutral pictures. Then some questionnaires were completed, including binge eating, food cravings, common reward sensitivity and behavioral inhibition, emotional state, and then snack food. The group reported more binge eating behavior, eating out of control, food craving, and marginal significant reward sensitivity and inhibition. After the scan, the binge eating group also fed more chocolates. The lower frontal gyrus, the middle frontal gyrus and the middle temporal gyrus were more active while watching the picture of the food, and the wedge was more active. In the anterior leaf, the cingulate gyrus was less activated. The consumption of chocolate was significantly negatively correlated with the middle frontal gyrus and the activation of the front of the wedge. In conclusion, these results showed that the specific brain area of impulse control was important for food food stimulation and feeding in bingia individuals. In study 4, the inhibition reaction was examined with the Go/No-Go task. In this task, "No-Go" or control tests were made up of high calorie food images. Based on structural interviews, 17 women met the diagnostic criteria for binge eating in DSM-V, and 17 women without eating disorders were used as control groups. All subjects completed the Go/ No-Go task and performed a f MRI scan, then completed the related questions. In the questionnaire survey, the individuals reported high levels of impulsiveness, eating out of control, more diet and attention to body weight, body weight, eating, and higher depression, anxiety and stress in individuals with binge eating disorder. In the Go/No-Go task, more asthenia in binge eating individuals responded to their control defects. In high calorie food maps In the "No-Go" response, binge eating individuals have more activation on the insula. The insula contains the primary taste cortex, also involves anticipation and eating of food. At the same time, binge eating individuals also have more activation in the precentral and central back. These areas involve sensory perception, while individuals are exposed to food clues. The region also activates. These results suggest that individuals with binge eating disorder may be less controlled by the increase in the reward sensitivity to high calorie food cues, and require more control during inhibition. In study 5, resting state functional magnetic resonance (fMRI) was used to study the spontaneous brain signals in individuals and control groups of binge eating disorders in 4. Low frequency amplitude. The results showed that individuals in the prefrontal lobe, middle frontal gyrus, and upper frontal gyrus had higher activity and lower activity in the temporal gyrus. Further analysis found that the body mass index (BMI) was positively related to the activity of the orbitofrontal cortex, OFC, and the impulsivity score and the dorsolateral. The activity of the dorsal-lateral prefrontal cortex (DLPFC) is positively correlated. The functional connection between the orbital prefrontal cortex and the dorsolateral prefrontal cortex is significantly greater than that of the control group. These results suggest that the increase in the functional connection between the frontal cortex and the dorsolateral prefrontal cortex plays an important role in the pathophysiology of the disease. Use. In study 6, the brain activity and subsequent eating behavior of food images were discussed mainly in individuals and control groups of binge eating disorder. The effects of acute stress on the food were studied. The.19 names of the subjects and control groups were randomly assigned to the stress group (the task of cold pressure pain, negative feedback) and the neutral group (non pain). Then they looked at the task and gave positive feedback. Then they watched pictures of food and neutral pictures and performed functional magnetic resonance (fMRI). After the completion of the scans, the subjects filled out questionnaires and fed snacks. The results showed that individuals who were more likely to enjoy high calorie foods under stress conditions were less activated in the hippocampus and under stress conditions. More importantly, more importantly, more importantly, in all subjects, the hippocampus activation was negatively related to the number of chocolates when watching high calorie foods. The results of this study showed that negative acute stress could reduce the activation of control areas, and these areas were associated with food clues and advances in individuals with binge eating disease. Food related. In a summary of the following findings: women with binge eating behavior showed high level of reward sensitivity to high calorie food, and the less control ability, the more eating; in the food cue response and eating, food clues and food, reward and suppression of specific brain areas play an important role; the reward area (OFC) and inhibition. The increase in the functional connection of the control area (DLPFC) may lead to the occurrence and maintenance of binge eating disorder; negative stress reduction inhibits the activity of control areas and may lead to eating out of control. The findings of this paper provide evidence for the irritation sensitization theory of binge eating disorder.

【学位授予单位】：西南大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：B842
，

本文编号：1882563