Increased Functional Connectivity Between Ventral Attention and Default Mode Networks in Adolescents With Bulimia Nervosa.
ABSTRACT: OBJECTIVE:Bulimia nervosa (BN) is characterized by excessive attention to self and specifically to body shape and weight, but the ventral attention (VAN) and default mode (DMN) networks that support attentional and self-referential processes are understudied in BN. This study assessed whether altered functional connectivity within and between these networks contributes to such excessive concerns in adolescents with BN early the course of the disorder. METHOD:Resting-state functional magnetic resonance images were acquired from 33 adolescents with BN and 37 healthy control adolescents (12-21 years) group matched by age and body mass index. Region-of-interest analyses were performed to examine group differences in functional connectivity within and between the VAN and DMN. In addition associations of VAN-DMN connectivity with BN symptoms, body shape/weight concerns, and sustained attention were explored using the Continuous Performance Test (CPT). RESULTS:Compared with control adolescents, those with BN showed significantly increased positive connectivity between the right ventral supramarginal gyrus and all DMN regions and between the right ventrolateral prefrontal cortex and the left lateral parietal cortex. Within-network connectivity did not differ between groups. VAN-DMN connectivity was associated with BN severity and body shape/weight concerns in the BN group. No significant group-by-CPT interactions on VAN-DMN connectivity were detected. CONCLUSION:Increased positive VAN-DMN connectivity in adolescents with BN could reflect abnormal engagement of VAN-mediated attentional processes at rest, perhaps related to their excessive attention to self-referential thoughts about body shape/weight. Future studies should further investigate these circuits as targets for the development of early interventions aimed at decreasing excessive body shape/weight concerns.
Project description:INTRODUCTION:The etiology of bulimic-type eating (BTE) disorders such as binge eating disorder (BED) and bulimia nervosa (BN) is still largely unknown. Brain networks subserving the processing of rewards, emotions, and cognitive control seem to play a crucial role in the development and maintenance of eating disorders. Therefore, further investigations into the neurobiological underpinnings are needed to discern abnormal connectivity patterns in BTE disorders. METHODS:The present study aimed to investigate functional as well as seed-based connectivity within well-defined brain networks. Twenty-seven individuals with BED, 29 individuals with BN, 28 overweight, and 30 normal-weight control participants matched by age, gender, and education underwent resting-state functional magnetic resonance imaging. Functional connectivity was assessed by spatial group independent component analysis and a seed-based correlation approach by examining the default mode network (DMN), salience network (SN), and executive network (EN). RESULTS:Group comparisons revealed that BTE disorder patients exhibit aberrant functional connectivity in the dorsal anterior cingulate cortex (dACC) within the SN, as well as in the medial prefrontal cortex within the DMN. Furthermore, BED and BN groups differed from each other in functional connectivity within each network. Seed-based correlational analysis revealed stronger synchronous dACC-retrosplenial cortex activity in the BN group. CONCLUSION:Our findings demonstrate abnormalities in brain networks involved in salience attribution, self-referential processing, and cognitive control in bulimic-type eating disorders. Together with our observation of functional connectivity differences between BED and BN, this study offers a differentiated account of both similarities and differences regarding brain connectivity in BED and BN.
Project description:Anorexia nervosa (AN) is an illness that frequently begins during adolescence and involves weight loss. Two groups of adolescent girls (AN-A, weight-recovered following AN) and (HC-A, healthy comparison) completed a functional magnetic resonance imaging task involving social evaluations, allowing comparison of neural activations during self-evaluations, friend-evaluations, and perspective-taking self-evaluations. Although the two groups were not different in their whole-brain activations, anxiety and body shape concerns were correlated with neural activity in a priori regions of interest. A cluster in medial prefrontal cortex and the dorsal anterior cingulate correlated with the body shape questionnaire; subjects with more body shape concerns used this area less during self than friend evaluations. A cluster in medial prefrontal cortex and the cingulate also correlated with anxiety such that more anxiety was associated with engagement when disagreeing rather than agreeing with social terms during self-evaluations. This data suggests that differences in the utilization of frontal brain regions during social evaluations may contribute to both anxiety and body shape concerns in adolescents with AN. Clinical follow-up was obtained, allowing exploration of whether brain function early in course of disease relates to illness trajectory. The adolescents successful in recovery used the posterior cingulate and precuneus more for friend than self evaluations than the adolescents that remained ill, suggesting that neural differences related to social evaluations may provide clinical predictive value. Utilization of both MPFC and the precuneus during social and self evaluations may be a key biological component for achieving sustained weight-recovery in adolescents with AN.
Project description:OBJECTIVE:Recent evidence has suggested an increased rate of comorbid ADHD and subclinical attentional impairments in bulimia nervosa (BN) patients. However, little is known regarding the underlying neural mechanisms of attentional functions in BN. METHOD:Twenty BN patients and twenty age- and weight-matched healthy controls (HC) were investigated using a modified version of the Attention Network Task (ANT) in an fMRI study. This design enabled an investigation of the neural mechanisms associated with the three attention networks involved in alerting, reorienting and executive attention. RESULTS:The BN patients showed hyperactivation in parieto-occipital regions and reduced deactivation of default-mode-network (DMN) areas during alerting compared with HCs. Posterior cingulate activation during alerting correlated with the severity of eating-disorder symptoms within the patient group. Conversely, BN patients showed hypoactivation during reorienting and executive attention in anterior cingulate regions, the temporo-parietal junction (TPJ) and parahippocampus compared with HCs, which was negatively associated with global ADHD symptoms and impulsivity, respectively. DISCUSSION:Our findings demonstrate altered brain mechanisms in BN associated with all three attentional networks. Failure to deactivate the DMN and increased parieto-occipital activation required for alerting might be associated with a constant preoccupation with food or body image-related thoughts. Hypoactivation of executive control networks and TPJ might increase the likelihood of inattentive and impulsive behaviors and poor emotion regulation. Thus, dysfunction in the attentional network in BN goes beyond an altered executive attentional domain and needs to be considered in the diagnosis and treatment of BN.
Project description:Functional magnetic resonance imaging research suggests that major depressive disorder (MDD) in both adults and adolescents is marked by aberrant connectivity of the default mode network (DMN) during resting state. However, emotional dysregulation is also a key feature of MDD. No studies to date have examined emotion-related DMN pathology in adolescent depression. Comprehensively understanding the dynamics of DMN connectivity across brain states in individuals with depression with short disease histories could provide insight into the etiology of MDD.We collected functional magnetic resonance imaging data during an emotion identification task and during resting state from 26 medication-free adolescents (13-17 years old) with MDD and 37 well-matched healthy control subjects. We examined between-group differences in blood oxygenation level-dependent task responses and emotion-dependent and resting-state functional connectivity of the two primary nodes of the DMN: medial prefrontal cortex and posterior cingulate cortex (PCC). Additionally, we examined between-group differences in DMN functional connectivity and its relationship to depression severity and onset.Relative to healthy control subjects, unmedicated adolescents with MDD demonstrated reduced medial prefrontal cortex and PCC emotion-related deactivation and greater medial prefrontal cortex and PCC emotion-dependent functional connectivity with precuneus, cingulate gyrus, and striatum/subcallosal cingulate gyrus. The PCC-subcallosal cingulate connectivity remained inflexibly elevated in the subjects with MDD versus healthy control subjects during resting state. Stronger PCC emotion-dependent functional connectivity was associated with greater depression severity and an earlier age of depression onset.Adolescent depression is associated with inflexibly elevated DMN connections. Given more recent evidence of DMN maturation throughout adolescence, our findings suggest that early-onset depression adversely affects normal development of functional brain networks.
Project description:The triple network model that consists of the default-mode network (DMN), central-executive network (CEN), and salience network (SN) has been suggested as a powerful paradigm for investigation of network mechanisms underlying various cognitive functions and brain disorders. A crucial hypothesis in this model is that the fronto-insular cortex (FIC) in the SN plays centrally in mediating interactions between the networks. Using a machine learning approach based on independent component analysis and Bayesian network (BN), this study characterizes the directed connectivity architecture of the triple network and examines the role of FIC in connectivity of the model. Data-driven exploration shows that the FIC initiates influential connections to all other regions to globally control the functional dynamics of the triple network. Moreover, stronger BN connectivity between the FIC and regions of the DMN and the CEN, as well as the increased outflow connections from the FIC are found to predict individual performance in memory and executive tasks. In addition, the posterior cingulate cortex in the DMN was also confirmed as an inflow hub that integrates information converging from other areas. Collectively, the results highlight the central role of FIC in mediating the activity of large-scale networks, which is crucial for individual cognitive function.
Project description:The clinical presentation of anorexia nervosa (AN) is characterized by preoccupation with body experience, intrusive concerns regarding shape, and pathological fears of weight gain. These symptoms are suggestive of unrelenting self-focused attention. No research to date has characterized self-focused attention (SFA) in AN nor examined neurocognitive features that may facilitate an excessive, rigid, or sustained focus on one's appearance.This study examined SFA, body image disturbance, and executive functioning in women with current anorexia nervosa (AN-C; n?=?24), a history of AN who were weight-restored at the time of the study (WR; n?=?19), and healthy controls (n?=?24).Private and public SFA were highest among WR and lowest among AN-C. Shape concerns were negatively correlated with SFA, especially among AN-C, after controlling for depression and social anxiety symptoms.Lower levels of SFA among AN-C were unexpected and suggest the acute state of AN may lessen pathological self-focus, negatively reinforcing symptoms. In addition, body image concerns may distract from general SFA. Deficits in executive attention may explain these findings, as each one unit increase in perseverative errors among AN-C participants was associated with an almost one-half unit decrease in public SFA.
Project description:The capacity of patients with anorexia nervosa (AN) to resist food-based rewards is often assumed to reflect excessive self-control. Previous cross-sectional functional magnetic resonance imaging (fMRI) studies utilizing the delay discounting (DD) paradigm, an index of impulsivity and self-control, suggested altered neural efficiency of decision-making in acutely underweight patients (acAN) and a relative normalization in long-term, weight-recovered individuals with a history of AN (recAN). The current longitudinal study tested for changes in functional magnetic resonance imaging (fMRI) activation during DD associated with intensive weight restoration treatment. A predominately adolescent cohort of 22 female acAN patients (mean age-15.5 years) performed an established DD paradigm during fMRI at the beginning of hospitalization and again after partial weight restoration (?12% body mass index (BMI) increase). Analyses investigated longitudinal changes in both reward valuation and executive decision-making processes. Additional exploratory analyses included comparisons with data acquired in aged-matched healthy controls (HC) as well as probes of functional connectivity between empirically identified nodes of the "task-positive" frontoparietal control network (FPN) and "task-negative" default-mode network (DMN). While treatment was not associated with changes in behavioral DD parameters or activation, specific to reward processing, deactivation of the DMN during decision-making was significantly less pronounced following partial weight restoration. Strengthened DMN activation during DD might reflect a relative relaxation of cognitive overcontrol or improved self-referential, decision-making. Together, our findings present further evidence that aberrant decision-making in AN might be remediable by treatment and, therefore, might constitute an acute effect rather than a core trait variable of the disorder.
Project description:Post-traumatic stress disorder (PTSD) is characterized by intrusions, re-experiencing, avoidance and hyperarousal. These symptoms might be linked to dysfunction in core neurocognitive networks subserving self-referential mental processing (default mode network, DMN), detection of salient stimuli (salience network, SN) and cognitive dysfunction (central executive network, CEN). Resting state studies in adolescent PTSD are scarce and findings are inconsistent, probably due to differences in patient symptom severity. Resting state brain activity was measured in 14 adolescents with severe PTSD and 24 age-matched controls. Seed-based connectivity analyses were used to examine connectivity between the DMN and the whole brain, including regions from other networks (SN and CEN). The relationships of network properties with symptom dimensions (severity, anxiety and depression) and episodic memory were also examined. Analyses revealed decreased within-DMN connectivity (between PCC and occipital cortex) in patients compared to controls. Furthermore, within-DMN connectivity (between PCC and hippocampus) correlated negatively with symptom dimensions (severity and anxiety), while increased connectivity (DMN-SN and DMN-CEN) correlated positively with episodic memory measures. These abnormal network properties found in adolescent PTSD corroborate those previously reported in adult PTSD. Decreased within-DMN connectivity and disrupted DMN-SN and DMN-CEN coupling could form the basis for intrusive trauma recollection and impaired episodic autobiographical recall in PTSD.
Project description:Classifying eating disorders in youth is challenging in light of developmental considerations and high rates of diagnostic migration. Understanding the transactional relationships among eating disorder symptoms, both across the transdiagnostic spectrum and within specific diagnostic categories, may clarify which core eating disorder symptoms contribute to, and maintain, eating-related psychopathology in youth. We utilized network analysis to investigate interrelationships among eating disorder symptoms in 636 treatment-seeking children and adolescents (90.3% female) ages 6-18 years (M age = 15.4 ± 2.2). An undirected, weighted network of eating disorder symptoms was created using behavioral and attitudinal items from the Eating Disorder Examination. Across diagnostic groups, symptoms reflecting appearance-related concerns (e.g., dissatisfaction with shape and weight) and dietary restraint (e.g., a desire to have an empty stomach) were most strongly associated with other eating disorder symptoms in the network. Binge eating and compensatory behaviors (e.g., self-induced vomiting) were strongly connected to one another but not to other symptoms in the network. Network connectivity was similar across anorexia nervosa, bulimia nervosa, and otherwise specified feeding or eating disorder subgroups. Among treatment-seeking children and adolescents, dietary restraint and shape- and weight-related concerns appear to play key roles in the psychopathology of eating disorders, supporting cognitive-behavioral theories of onset and maintenance. Similarities across diagnostic categories provide support for a transdiagnostic classification scheme. Clinical interventions should seek to disrupt these symptoms early in treatment to achieve maximal outcomes. (PsycINFO Database Record
Project description:BACKGROUND:Obesity is associated with vascular risk factors that in turn, may increase dementia risk. However, higher body mass index (BMI) in late life may be neuroprotective. The possible neural mechanisms underlying the benefit of higher BMI on cognition in older adults are largely unknown. Thus, we used functional connectivity magnetic resonance imaging (fcMRI) to examine: (1) the relationship between BMI and functional brain connectivity; and (2) the mediating role of functional brain connectivity in the association between baseline BMI and change in cognitive function over a 12-month period. METHODS:We conducted a 12-month, prospective study among 66 community-dwelling older adults, aged 70 to 80 years, who were categorized as: normal weight (BMI from 18.50 to 24.99); overweight (BMI from 25.00 to 29.99); and obese (BMI ? 30.00). At baseline, participants performed a finger-tapping task during fMRI scanning. Relevant neural networks were initially identified through independent component analysis (ICA) and subsequently examined through seed-based functional connectivity analysis. At baseline and 12-months, we measured three executive cognitive processes: (1) response inhibition; (2) set shifting; and (3) working memory. RESULTS:Obese individuals showed lower task-related functional connectivity during finger tapping in the default mode network (DMN) compared with their healthy weight counterparts (p < 0.01). Lower task-related functional connectivity in the DMN at baseline was independently associated with better working memory performance at 12-months (p = 0.02). Finally, DMN functional connectivity during finger tapping significantly mediated the relationship between baseline BMI and working memory at 12-months (indirect effect: -0.155, 95% confidence interval [-0.313, -0.053]). CONCLUSIONS:These findings suggest that functional connectivity of the DMN may be an underlying mechanism by which higher BMI confers protective effects to cognition in late life.