Subcortical brain volume and cortical thickness in adolescent girls and women with binge eating

Altered connectivity patterns of medial and lateral orbitofrontal cortex underlie the severity of bulimic symptoms

Objective

Compared to clinical bulimia nervosa, sub-threshold bulimic symptoms are becoming more prevalent in non-clinical or general population, which is repeatedly linked with the connectivity in orbitofrontal cortex (OFC), including functionally heterogeneous the medial and lateral OFC (mOFC; lOFC). However, the specific connectivity patterns of the mOFC and lOFC in individuals with severe or mild bulimic symptoms (SB; MB) remain poorly understood.

Methods

We first utilized resting-state functional connectivity (FC) and spectral dynamic causal modeling (spDCM) to investigate abnormal functional and effective connectivity (EC) of OFC subregions in adults with different severity of bulimic. The SB group (n = 21), MB group (n = 114), and healthy controls (HC, n = 91) underwent rs-fMRI scans. A generalized linear model was applied to determine the OFC-seeded whole-brain FC across the three groups. Subsequently, spDCM was used to estimate differences in EC among the three groups based on the FC results.

Results

We observed a shared neural basis for SB and MB groups (i.e., weaker lOFC-superior parietal lobule connectivity), which may support the role of dysfunctional inhibitory control in general bulimic symptomatology. Whereas, SB group displayed greater lOFC-occipital pole connectivity than MB group, suggesting the specificity of the neural correlates of full-threshold/severe bulimia. The directional links from the mOFC to lOFC and amygdala could further explain the aberrant interactions of reward sensitivity with inhibitory control and homeostatic energy in sub-threshold/mild condition.

Conclusion

The current study provides novel evidence that divergent connectivity patterns of the lOFC and mOFC may contribute to different severities of bulimia, which will expands our understanding of the neurobiological substrates underlying bulimia across a spectrum from healthy to unhealthy.

Aberrant functional connectivity between reward and inhibitory control networks in pre-adolescent binge eating disorder

BACKGROUND

Behavioral features of binge eating disorder (BED) suggest abnormalities in reward and inhibitory control. Studies of adult populations suggest functional abnormalities in reward and inhibitory control networks. Despite behavioral markers often developing in children, the neurobiology of pediatric BED remains unstudied.

METHODS

58 pre-adolescent children (aged 9-10-years) with BED (mBMI = 25.05; s.d. = 5.40) and 66 age, BMI and developmentally matched control children (mBMI = 25.78; s.d. = 0.33) were extracted from the 3.0 baseline (Year 0) release of the Adolescent Brain Cognitive Development (ABCD) Study. We investigated group differences in resting-state functional MRI functional connectivity (FC) within and between reward and inhibitory control networks. A seed-based approach was employed to assess nodes in the reward [orbitofrontal cortex (OFC), nucleus accumbens, amygdala] and inhibitory control [dorsolateral prefrontal cortex, anterior cingulate cortex (ACC)] networks via hypothesis-driven seed-to-seed analyses, and secondary seed-to-voxel analyses.

RESULTS

Findings revealed reduced FC between the dlPFC and amygdala, and between the ACC and OFC in pre-adolescent children with BED, relative to controls. These findings indicating aberrant connectivity between nodes of inhibitory control and reward networks were corroborated by the whole-brain FC analyses.

CONCLUSIONS

Early-onset BED may be characterized by diffuse abnormalities in the functional synergy between reward and cognitive control networks, without perturbations within reward and inhibitory control networks, respectively. The decreased capacity to regulate a reward-driven pursuit of hedonic foods, which is characteristic of BED, may in part, rest on this dysconnectivity between reward and inhibitory control networks.

Gray matter volume and functional connectivity underlying binge eating in healthy children

PURPOSE

As a maladaptive disordered eating behavior, binge eating (BE) onset has been reported in children as young as eight years old and is linked with a range of negative psychological consequences. However, previous neuroimaging research of BE has mainly focused on adults in clinical conditions, and little is known about the potential neurostructural and neurofunctional bases of BE in healthy children.

METHODS

In this study, we examined these issues in 76 primary school students (mean age = 9.86 years) using voxel-based morphometry and resting-state functional connectivity (rsFC) approaches.

RESULTS

After controlling for age, sex, and total intracranial volume/head motion, we observed that higher levels of BE were correlated with greater gray matter volumes (GMV) in the left fusiform and right insula and weaker rsFC between the right insula and following three regions: right orbital frontal cortex, left cingulate gyrus, and left superior frontal gyrus. No significant associations were observed between BE and regional white matter volume. Significant sex differences were found only in the relationship between BE and GMV in the left fusiform. Furthermore, the GMV- and rsFC-based predictive models (a machine-learning method) achieved significant correlations between the actual and predicted BE values, demonstrating the robustness of our findings.

CONCLUSION

The present study provides novel evidence for the brain structural and functional substrates of children's BE, and further reveals that the weakened communication between core regions associated with negative affectivity, reward responsivity, and executive function is strongly related to dysregulated eating.

LEVEL OF EVIDENCE

Level V, descriptive study.

Regional gray matter abnormalities in pre-adolescent binge eating disorder: A voxel-based morphometry study

BACKGROUND

Binge eating disorder (BED) is a pernicious psychiatric disorder which is linked with an array of multisystemic organ morbidity, broad psychiatric morbidity, and obesity. Despite behavioral markers often developing in early childhood, the neurobiological markers of early-onset BED remain understudied, and developmental pathophysiology remains poorly understood.

METHODS

71 preadolescent children (aged 9-10-years) with BED and 74 age, BMI and developmentally matched control children were extracted from the 3.0 baseline (Year 0) release of the Adolescent Brain Cognitive Development (ABCD) Study. We investigated group differences in gray matter density (GMD) via voxel-based morphometry (VBM). We additionally performed region of interest analyses, assessing the association between GMD in nodes of the reward (orbitofrontal cortex; OFC) and inhibitory control (dorsolateral prefrontal cortex; dlPFC) networks, and parent-reported behavioral inhibition and approach tendencies.

RESULTS

Diffuse elevations in cortical GMD were noted in those with BED, which spanned prefrontal, parietal, and temporal regions. No areas of reduced GMD were noted in those with BED. No alterations in subcortical GMD were noted. Brain-behavioral associations suggest a distinct and negative relationship between GMD in the OFC and dlPFC, respectively, and self-reported markers of hedonic behavioral approach tendencies.

CONCLUSIONS

Early-onset BED may be characterized by diffuse morphological abnormalities in gray matter density, suggesting alterations in cortical architecture which may reflect decreased synaptic pruning and arborization, or decreased myelinated fibers and therefore inter-regional afferents.