The Brain Mechanisms Research Of Inhibition Control Between Successful And Failed Restraint Eaters

Eating is essential to our human beings.With the development of economy,the food is sufficient and could be obtained conveniently nowadays.Therefore,how to keep fit in an environment full of food temptation is a both theoretical and practical subject.Restrained eating refers to restrict food intake or limit high calorie intake for long periods in order to control weight.Although less than the counterparts in western developed countries,the number of eating disorders/obesity in China has been increasing rapidly.Diet related problems have threatened the physical and mental health of people and caused a series of social problems.Therefore,systematically research on restrained eating(RE)could not only enrich and expand the theory of diet problems,but also helpful for the prevention and treatment of eating disorders.Most importantly,previous studies on RE have not systematically explored the difference between successful restrained eaters(S-REs)and failed restrained eaters(F-REs).Based on the study of “why some succeed some fail in dieting among restrained eaters(REs)”,we used functional Magnetic Resonance Imaging(f MRI)and Event-Related Potential(ERP)to examine whether inhibition control can explain REs success in dieting.First,ERP and f MRI techonology were used to explore the capacity of inhibition control among individuals including S-REs,F-REs and normal in study one.Experiment 1,participants including S-REs(n=15),F-REs(n=15)and normal(n=15)were required reponse to low caloric food pictures as quickly as possible(Go)and inhibit response to high caloric food pictures(Nogo)in a Go-Nogo task.Behavior results showed that there were no difference amonge three groups on the response time and accuracy.ERP results showed that compared to normal and F-REs,S-REs elicited a more positive P2 component.Between 200-250 ms,compared to S-REs,F-REs elicited a more negative N2 component.Under both low and high caloric food pictures conditions,S-REs elicited a more positive P300 in the time window of 300-500 ms thanF-REs.The design of experiment 2 was the same as experiment one.Behavior results showed that there were no difference about accuracy between three groups,while the response time is faster for S-REs than F-REs.f MRI results showed that S-REs and F-REs both showed widespread activation in brain regions associated with food reward and attention comparing to normal under Go condition(i.e.,orbitofrontal cortex(OFC))More interesting,S-REs showed stronger activation in areas of executive function and inhibition(i.e.,Cerebellum,Middle Frontal Gyrus),while F-REs showed stronger activation in reward areas under Nogo condition(i.e.,Middle orbitofrontal cortex,OFC).In sum,findings revealed that,in women who are successful in dieting,food temptations may trigger processes of successful inhibition control,whereas F-REs may seem to forget about their diet goal when they are confronted with attractive food,thereby risking the chance to overeat.Second,in the present study,we used the high temporal resolution advantage of ERP to explore the capacity of inhibition control between S-REs and F-REs in the hungry and sated state.In the experiment three,participants were asked to response to low caloric food(Go condition)and inhibit response to high caloric food(No-go condition)as quickly and correctly as possible in a classic Go/No-go task.The subjects(N=25)which were divided in two subgroups including S-REs and F-REs were asked to do not eat anything except water during eighteen hours.Behavior results showed that there were no siginificant differences between two groups on the response time and accuracy.ERP results showed that high caloric food pictures elicited more negative N1 and N2 in the early cognitive processing among F-REs in the hungry state.Whereas,S-REs induced a more negative wave on low caloric food pictures.That is to say,F-REs need more effort to monitor conflict detection to high caloric food,while S-REs pay more attention to low caloric food in the daily lify,and so there is a relatively large conflict to low caloric food.Our results suggeted that hungry state effect early processing of food related information.The participants were asked to eat the food which they most liked until sated and then we investigated the capacity of inhibition control between S-REs and F-REs in experiment 4.We explored the difference between two groups in the sated state.Behavior results showed that there were no siginificant differences on the response time and accuracy.ERP results showed that under thelow caloric condition,S-REs elicited a more negative N170 than F-REs.In addition,high caloric food pictures elicited a more positive P2 among S-REs.High caloric food pictures elicited a large late negative component among F-REs.The present study hintF-REs showed great conflict to high caloric food.While F-REs would overeat and then pay less attention to high caloric food after the food intake.In contrast,S-REs can evoke diet goal.Combined with the experiments 3 and 4,results showed that the inner state(hungry and sated)of restrained eaters had effect on eating.In the hungry state,F-REs need more effort to monitor conflict to high caloric food,while S-REs were much more sensitivity to low caloric food.For the choice of food,F-REs selected more high caloric food regardless of their physical condition,but the selection of S-REs was more low caloric food.Therefore,in the subsequent ERP experiments,the F-REs would start diet goal after sated and were not sensitive to high caloric food,but S-REs which did not reach the physiological boundary showed more sensitive to high calorie foods.Which might suggest that S-REs were successful on dieting.On the contrary,the F-REs get into the bad cycle of dieting.Third,alterations in brain structures and network associated with restrained eating(RE)represent one potentially important mechanism that contributes to difficulties in maintaining weight loss within this group.To evaluate this contention,we investigated associations between intentional,sustained restriction of food intake to lose or maintain body weight,and regional gray matter volume(r GMV)within a large non-clinical young adult,sample.Participants(150 women,108 men)completed measures of RE,DEBQ and demographics prior to undergoing an MRI scan.Voxel-based morphometry(VBM)evaluated strengths of association between RE scores and r GMV in experiment5.Experimen 5 showed that higher RE levels corresponded to more r GMV in regions linked to risk of overeating and binge-eating including the left insula and OFC.Conversely,RE had significant negative correlations with r GMV in the left and right posterior cingulum gyrus,regions linked to inhibitory control and potential risk for future weight gain.Meanwhile,we used VBM technology to evaluate the association between DEBQ scores and r GMV in experiment 6.Experimen 6 showed that higher restrained scale of DEBQ levels corresponded to more r GMV in middle temporal gyrus region,and emotional eating of DEBQ linked to risk of overeating and binge-eating including the caudate.Wheras external eating of DEBQ was negatively corresponded to more r GMV in precuneus region.Further,rest-f MRI was used to explore the relationship between restrained eating and brain spontaneous neural activity among 150 healthy females.Results showed that there were some significant correlations among the index of Regional Homogeneit(Re Ho),amplitude of low frequency fluctuations(ALFF),function connection density(FCD)and restrained scale of DEBQ includinginsula,precentral gyrus and anterior cingulate cortex(ACC).To be specific,high restrained eating level was positively realted to Re Ho/FCD/ALFF value of right insula and ACC which were related with emotion and reward.The results might imply that there were different among different level restrained eating.Together,findings suggested individual differences in RE among young adults correspond to GMV variability and brain network in regions linked to overweight and obesity risk.Taken together,the inhibition control capacity is different between S-REs and F-REs.F-REs with low or damaged inhibition control would more tendency to overeat,especially in the hungry state.In addition,different restrained level present some differences in the brain structure,someone were more likely failed would had large grey matter volume in the reward regions.The main innovation of this study: first,we used ERP and f MRI technology to systematically explore the inhibition control capacity between S-REs and F-REs;second,to further verify the inhibition control capacity between two groups in the hungry and sated state;third,we used the VBM techonology and rest-f MRI to supply undermine potential mechanism of eating.