The Neural Mechanisms In Attentional Bias On Food Cues For Restraint Eaters

Eating is essential to our survival and daily life, and it's well-known that food temptation is available easily. Therefore, how to successfully control one's weight in an environment that is full of food temptation is an important issue with practical significance. Restricted eating refers to consistent, cognitively-mediated efforts to restrict eating for the purpose of weight control. Numerous studies has shown consistently that restrained eating can predict the development of Bing eating, overweight and obesity, and is also the key factor to the transmission from abnormal mental to abnormal behaviors in the development of eating disorders. On the other hand, the prevalence of eating disorders/obesity in China has been increasing rapidly and emerged ahead, although the number of eating disorders/obesity was limited and less than that of the counterparts in western developed countries. The arising problems with eating behaviors has been imposed higher risk on public physical and mental health, and also evoked a series of social problems. Therefore, systematically research on restrained eating will be benefit to explore the origin of eating disorder and other related problems with eating behaviors, enrich and expand theories of eating behavior and also promote more effectively and specially preventions and treatment. Prior findings focused on behavioral level of restrained eating, and studies to investigate the neural correlates of restrained eating were less. Meanwhile, the available findings were inconsistent and mixed. However, it is very important in theory, practice and application aspects to carry out systematic investigations of restrained eating in Chinese background.Our research aimed to examine the basic question in the filed of dieting why some restrained eaters can successfully control their weight and others can't, and systematically explored the neural correlates of attentional bias among successful and unsuccessful restrained eaters with ERP and fMRI technologies. Our research comprised three behavioral studies, four Event-Related Potentials (ERPs) studies and an fMRI study. At the First, behavioral studies tested the reliability of restrained eating scales among Chinese female undergraduates (study1,2), and developed a standardized Chinese food picture system (study3). At the Second, in ERP studies,(masked) visual Dot-Probe paradigm was used to investigate the attentional bias on food cues in sub marginal and marginal levels (study4,5). Go/NOGO task and Two-task Oddball paradigm were also employed to investigate the general inhibition and specific inhibition among restrained eaters (study6,7). At the last, in an fMRI study, Food Cue Task was used to investigate the brain activation of food cues processing between successful and unsuccessful restrained eaters (study8). The main concludes were as follows.(1) The revised restrained scales, which included Restraint Scale and Dutch Eating Behavior Questionnaire, were stable in factor structure, excellent in reliability and validity, and can be used as a useful tool in evaluating eating behaviors.(2) This study developed a standardized Chinese food picture system that covered basic structures of Chinese diet, and also established the important indexes of food attributes among Chinese female undergraduates. The food system had sound reliability, can provide important basis for follow-up study.(3) Our research redefined successful restrained dieters and unsuccessful restrained eaters in a more scientific way, and also provided the conceptualized definition. Successful restrained eaters control their eating behavior consistently and strictly, and were characterized by higher restrained and lower disinhibitied level, with normal weight, and had maintained their current weight stable for at least6month. Unsuccessful restrained eaters control their eating behavior consistently and strictly, and were characterized by higher restrained and higher disinhibited level, and had weight loss for at least6month. These definitions would be benefit to more subsequent research.(4) These results showed that both successful restrained eaters and unsuccessful restrained eaters showed attentional bias toward food cues, but each demonstrated significantly different components. The components of attentional bias for successful restrained eaters were attention alluring and attention avoiding. And components of attentional bias for unsuccessful restrained eaters were attention alluring, attention avoiding, attention disengaging difficult.(5) The attention bias to food cues for restrained eaters was related to inhibition deficit. Unsuccessful restrained eaters not the successful restrained eaters showed deficit in general inhibition. On the other hand, successful restrained eaters were deficit in inhibition to high-energy food cues, and unsuccessful restrained eaters were sufficient in inhibition to both high-energy and low-energy food cues. (6) Both Successful and unsuccessful restrained eaters showed different brain activations in processing food cues. Relative to normal eaters, both restrained eaters showed stronger activations in brain cortexes related to reward and attention process, and successful restrained eaters also showed stronger activations in brain cortexes related to executive and monitoring function.(7) There are different moderating mechanisms in attentional process of food cues for successful restrained eaters and unsuccessful restrained eaters. Relative to unsuccessful restrained eaters, successful restrained eaters showed stronger activation in the cortex of inhibition processing, such as Frontal; Relative to successful restrained eaters, unsuccessful restrained eaters showed greater activations in the cortex of reward processing, such as middle OFC. However, unsuccessful restrained eaters often used "Hot" mechanism to moderate the attention process of food cues, and successful restrained eaters often used "Cool mechanism" to moderate the attention process of food cues.(8) This study developed an attention processing model of food cues among successful restrained eaters and unsuccessful restrained eaters. The successful restrained eaters processed food cues differently from unsuccessful restrained eaters not only in the temporal process, but also in the brain activations.In conclusion, the research demonstrated that successful restrained eaters and unsuccessful restrained eaters showed different behavioral response mode as well as different neural mechanism. This indicated that restrained eating changed the eating behavior, and also changed the mode of cognitive process and brain activations Therefore, this study is important not only in theory contribution, but also in application value.