Reduced Resting-State Functional Connectivity in Current and Recovered Restrictive Anorexia Nervosa

Neuroimaging studies of resting-state functional magnetic resonance imaging in eating disorders

Eating disorders (EDs), including anorexia nervosa (AN), bulimia nervosa (BN), binge-eating disorder (BED), and pica, are psychobehavioral conditions characterized by abnormal eating behaviors and an excessive preoccupation with weight and body shape. This review examines changes in brain regions and functional connectivity in ED patients over the past decade (2013-2023) using resting-state functional magnetic resonance imaging (rs-fMRI). Key findings highlight alterations in brain networks such as the default mode network (DMN), central executive network (CEN), and emotion regulation network (ERN). In individuals with AN, there is reduced functional connectivity in areas associated with facial information processing and social cognition, alongside increased connectivity in regions linked to sensory stimulation, aesthetic judgment, and social anxiety. Conversely, BED patients show diminished connectivity in the dorsal anterior cingulate cortex within the salience network and increased connectivity in the posterior cingulate cortex and medial prefrontal cortex within the DMN. These findings suggest that rs-fMRI could serve as a valuable biomarker for assessing brain function and predicting treatment outcomes in EDs, paving the way for personalized therapeutic strategies.

EEG Spatial-temporal Dynamics of Resting-state Activity in Young Women with Anorexia Nervosa: Preliminary Evidence

The aim of this study was to provide preliminary evidence on temporal dynamics of resting-state brain networks in youth with anorexia nervosa (AN) using electroencephalography (EEG). Resting-state EEG data were collected in 18 young women with AN and 18 healthy controls (HC). Between-group differences in brain networks were assessed using microstates analyses. Five microstates were identified across all subjects (A, B, C, D, E). Using a single set of maps representative of the whole dataset, group differences were identified for microstates A, C, and E. A common-for-all template revealed a relatively high degree of consistency in results for reduced time coverage of microstate C, but also an increased presence of microstate class E. AN and HC had different microstate transition probabilities, largely involving microstate A. Using LORETA, for microstate D, we found that those with AN had augmented activations in the left frontal inferior operculum, left insula, and bilateral paracentral lobule, compared with HC. For microstate E, AN had augmented activations in the para-hippocampal gyrus, caudate, pallidum, cerebellum, and cerebellar vermis. Our findings suggest altered microstates in young women with AN associated with integration of sensory and bodily signals, monitoring of internal/external mental states, and self-referential processes. Future research should examine how EEG-derived microstates could be applied to develop diagnostic and prognostic models of AN.

Comprehensive elucidation of resting-state functional connectivity in anorexia nervosa by a multicenter cross-sectional study

BACKGROUND

Previous research on the changes in resting-state functional connectivity (rsFC) in anorexia nervosa (AN) has been limited by an insufficient sample size, which reduced the reliability of the results and made it difficult to set the whole brain as regions of interest (ROIs).

METHODS

We analyzed functional magnetic resonance imaging data from 114 female AN patients and 135 healthy controls (HC) and obtained self-reported psychological scales, including eating disorder examination questionnaire 6.0. One hundred sixty-four cortical, subcortical, cerebellar, and network parcellation regions were considered as ROIs. We calculated the ROI-to-ROI rsFCs and performed group comparisons.

RESULTS

Compared to HC, AN patients showed 12 stronger rsFCs mainly in regions containing dorsolateral prefrontal cortex (DLPFC), and 33 weaker rsFCs primarily in regions containing cerebellum, within temporal lobe, between posterior fusiform cortex and lateral part of visual network, and between anterior cingulate cortex (ACC) and thalamus (p < 0.01, false discovery rate [FDR] correction). Comparisons between AN subtypes showed that there were stronger rsFCs between right lingual gyrus and right supracalcarine cortex and between left temporal occipital fusiform cortex and medial part of visual network in the restricting type compared to the binge/purging type (p < 0.01, FDR correction).

CONCLUSION

Stronger rsFCs in regions containing mainly DLPFC, and weaker rsFCs in regions containing primarily cerebellum, within temporal lobe, between posterior fusiform cortex and lateral part of visual network, and between ACC and thalamus, may represent categorical diagnostic markers discriminating AN patients from HC.

Task fMRI studies investigating inhibitory control in patients with obsessive-compulsive disorder and eating disorders: A comparative meta-analysis

BACKGROUND

Obsessive-compulsive disorder (OCD) and eating disorders (EDs) share similarities in terms of clinical characteristics and deficits in inhibitory control.

OBJECTIVE

To investigate whether inhibitory control could serve as a common behavioural phenotype between OCD and EDs and whether it might be underpinned by shared and/or distinct neural signatures.

METHOD

We performed a quantitative meta-analysis of brain function abnormalities during the inhibitory control task-based functional Magnetic Resonance Imaging (fMRI) scan across patients with OCD and EDs using seed-based d mapping (SDM).

RESULTS

The meta-analysis included sixteen OCD fMRI studies and ten EDs fMRI studies. And findings revealed that patients with OCD showed hypoactivation relative to healthy controls and patients with EDs in the anterior cingulate cortex, while compared to healthy controls and patients with OCD, patients with EDs showed hypoactivation in the right insula.

CONCLUSIONS

Patients with OCD and EDs are inclined to exhibit impaired inhibitory control, which may be attributed to different abnormal patterns of neural activation.

Central Autonomic Network Alterations in Anorexia Nervosa Following Peripheral Adrenergic Stimulation

BACKGROUND

Anorexia nervosa (AN) is characterized by low body weight, disturbed eating, body image disturbance, anxiety, and interoceptive dysfunction. However, the neural processes underlying these dysfunctions in AN are unclear. This investigation combined an interoceptive pharmacological probe, the peripheral β-adrenergic agonist isoproterenol, with resting-state functional magnetic resonance imaging to examine whether individuals with AN relative to healthy comparison participants show dysregulated neural coupling in central autonomic network brain regions.

METHODS

Resting-state functional magnetic resonance imaging was performed in 23 weight-restored female participants with AN and 23 age- and body mass index-matched healthy comparison participants before and after receiving isoproterenol infusions. Whole-brain functional connectivity (FC) changes were examined using central autonomic network seeds in the amygdala, anterior insular cortex, posterior cingulate cortex, and ventromedial prefrontal cortex after performing physiological noise correction procedures.

RESULTS

Relative to healthy comparison participants, adrenergic stimulation caused widespread FC reductions in the AN group between central autonomic network regions and motor, premotor, frontal, parietal, and visual brain regions. Across both groups, these FC changes were inversely associated with trait anxiety (State-Trait Anxiety Inventory-Trait), trait depression (9-item Patient Health Questionnaire), and negative body image perception (Body Shape Questionnaire) measures, but not with changes in resting heart rate. These results were not accounted for by baseline group FC differences.

CONCLUSIONS

Weight-restored females with AN show a widespread state-dependent disruption of signaling between central autonomic, frontoparietal, and sensorimotor brain networks that facilitate interoceptive representation and visceromotor regulation. Additionally, trait associations between central autonomic network regions and these other brain networks suggest that dysfunctional processing of interoceptive signaling may contribute to affective and body image disturbance in AN.

Disrupted longitudinal restoration of brain connectivity during weight normalization in severe anorexia nervosa

Altered intrinsic brain connectivity of patients with anorexia nervosa has been observed in the acute phase of the disorder, but it remains unclear to what extent these alterations recover during weight normalization. In this study, we used functional imaging data from three time points to probe longitudinal changes in intrinsic connectivity patterns in patients with severe anorexia nervosa (BMI ≤ 15.5 kg/m²) over the course of weight normalization. At three distinct stages of inpatient treatment, we examined resting-state functional connectivity in 27 women with severe anorexia nervosa and 40 closely matched healthy controls. Using network-based statistics and graph-theoretic measures, we examined differences in global network strength, subnetworks with altered intrinsic connectivity, and global network topology. Patients with severe anorexia nervosa showed weakened intrinsic connectivity and altered network topology which did not recover during treatment. The persistent disruption of brain networks suggests sustained alterations of information processing in weight-recovered severe anorexia nervosa.

Structural and Functional Brain Changes in Acute Takotsubo Syndrome

BACKGROUND

Takotsubo syndrome mimics an acute myocardial infarction, typically in the aftermath of mental or physical stress.

OBJECTIVES

The mechanism by which emotional processing in the context of stress leads to significant cardiac injury is poorly understood, so a full exploration of brain structure and function in takotsubo syndrome patients merits investigation.

METHODS

Twenty-five acute (<5 days) takotsubo patients and 25 control subjects were recruited into this observational cross-sectional study. Surface-based morphometry was carried out on magnetic resonance imaging (MRI) brain scans to extract cortical morphology based on volume, thickness, and surface area with the use of Freesurfer. Cortical morphology general linear models were corrected for age, sex, photoperiod, and total brain volume. Resting-state functional MRI and diffusion tensor tractography images were preprocessed and analyzed with the use of the Functional Magnetic Resonance Imaging of the Brain Diffusion Toolbox and Functional Connectivity Toolbox.

RESULTS

There was significantly smaller total white matter and subcortical gray matter volumes in takotsubo (P < 0.001), with smaller total brain surface area but increased total cortical thickness (both P < 0.001). Individual gray matter regions (hippocampus and others) were significantly smaller in takotsubo (P < 0.001); only thalamus and insula were larger (P < 0.001). There was significant hyperfunctional and hypofunctional connectivity in multiple areas, including thalamus-amygdala-insula and basal ganglia (P < 0.05). All structural tractography connections were increased in takotsubo (P < 0.05).

CONCLUSIONS

The authors showed smaller gray and white matter volumes driven by smaller cortical surface area, but increased cortical thickness and structural tractography connections with bidirectional changes in functional connectivity linked to emotion, language, reasoning, perception, and autonomic control. These are interventional targets in takotsubo patients' rehabilitation.

Neurocognitive Endophenotypes for Eating Disorders: A Preliminary High-Risk Family Study

Eating disorders (EDs) are psychiatric disorders with a neurobiological basis. ED-specific neuropsychological and brain characteristics have been identified, but often in individuals in the acute phase or recovered from EDs, precluding an understanding of whether they are correlates and scars of EDs vs. predisposing factors. Although familial high-risk (FHR) studies are available across other disorders, this study design has not been used in EDs. We carried out the first FMH study in EDs, investigating healthy offspring of women with EDs and controls. We preliminarily aimed to investigate ED-related neurocognitive and brain markers that could point to predisposing factors for ED. Sixteen girls at FHR for EDs and twenty control girls (age range: 8−15), completed neuropsychological tests assessing executive functions. Girls also underwent a resting-state fMRI scan to quantify functional connectivity (FC) within resting-state networks. Girls at FHR for EDs performed worse on a cognitive flexibility task compared with controls (F = 5.53, p = 0.02). Moreover, they showed different FC compared with controls in several resting-state networks (p < 0.05 FDR-corrected). Differences identified in cognitive flexibility and in FC are in line with those identified in individuals with EDs, strongly pointing to a role as potential endophenotypes of EDs.

Anorexia nervosa as a disorder of the subcortical-cortical interoceptive-self

PURPOSE

Anorexia nervosa (AN) is characterized by a diminished capacity in perceiving the physiological correlates of interoceptive sensations, namely bodily self-consciousness. Given the neural division of self-processing into interoceptive-, exteroceptive- and mental-self, we hypothesize neural deficits in the interoceptive-processing regions in AN.

METHODS

To prove this, we reviewed resting state (rs), task and rest-task studies in AN literature.

RESULTS

Neuronal data demonstrate the following in AN: (i) decreased rs-functional connectivity (rsFC) of subcortical-cortical midline structures (SCMS); (ii) reduced rsFC between medial (default-mode network/DMN and salience network/SN) and lateral (executive-control network/ECN) cortical regions; (iii) decreased rsFC in mainly the regions of the interoceptive-self; (iv) altered activity with overall increased activity in response to sensory/body image stimuli, especially in the regions of the interoceptive-self; (v) lack of a clear task-related distinction between own's and others' body image.

CONCLUSION

These data may indicate that rs-hypoconnectivity between SCMS, as neural correlate of a reduced intero-exteroceptive integration resulting in self-objectification, might be linked to overall increased activity in interoceptive regions during sensory/body image stimuli in AN, engendering an "anxious bodily self."

LEVEL OF EVIDENCE

I: Systematic review.

The Role of the Human Hypothalamus in Food Intake Networks: An MRI Perspective

Hypothalamus (HT), this small structure often perceived through the prism of neuroimaging as morphologically and functionally homogeneous, plays a key role in the primitive act of feeding. The current paper aims at reviewing the contribution of magnetic resonance imaging (MRI) in the study of the role of the HT in food intake regulation. It focuses on the different MRI techniques that have been used to describe structurally and functionally the Human HT. The latest advances in HT parcellation as well as perspectives in this field are presented. The value of MRI in the study of eating disorders such as anorexia nervosa (AN) and obesity are also highlighted.

Altered functional connectivity in adolescent anorexia nervosa is related to age and cortical thickness

INTRODUCTION

Functional networks develop throughout adolescence when anorexia nervosa (AN) normally debuts. In AN, cerebral structural alterations are found in most brain regions and may be related to the observed functional brain changes. Few studies have investigated the functional networks of the brain in adolescent AN patients.. The aim of this explorative study was to investigate multiple functional networks in adolescent AN patients compared to healthy age-matched controls (HC) and the relationship with age, eating disorder symptoms and structural alterations.

METHODS

Included were 29 female inpatients with restrictive AN, and 27 HC. All participants were between the ages of 12 to 18 years. Independent component analysis (ICA) identified 21 functional networks that were analyzed with multivariate and univariate analyses of components and group affiliation (AN vs HC). Age, age × group interaction and AN symptoms were included as covariates. Follow-up correlational analyses of selected components and structural measures (cortical thickness and subcortical volume) were carried out.

RESULTS

Decreased functional connectivity (FC) in AN patients was found in one cortical network, involving mainly the precuneus, and identified as a default mode network (DMN). Cortical thickness in the precuneus was significantly correlated with functional connectivity in this network. Significant group differences were also found in two subcortical networks involving mainly the hippocampus and the amygdala respectively, and a significant interaction effect of age and group was found in both these networks. There were no significant associations between FC and the clinical measures used in the study.

CONCLUSION

The findings from the present study may imply that functional alterations are related to structural alterations in selected regions and that the restricted food intake in AN patients disrupt normal age-related development of functional networks involving the amygdala and hippocampus.

Recovery-Associated Resting-State Activity and Connectivity Alterations in Anorexia Nervosa

BACKGROUND

Previous studies provided controversial insight on the impact of starvation, disease status, and underlying gray matter volume (GMV) changes on resting-state functional magnetic resonance imaging alterations in anorexia nervosa (AN). Here, we adapt a combined longitudinal and cross-sectional approach to disentangle the effects of these factors on resting-state alterations in AN.

METHODS

Overall, 87 female subjects were included in the study: adolescent patients with acute AN scanned at inpatient admission (n = 22, mean age 15.3 years) and at discharge (n = 21), patients who recovered from AN (n = 21, mean age 22.3 years), and two groups of healthy age-matched control subjects (both n = 22, mean age 16.0 and 22.5 years, respectively). Whole-brain measures of resting-state activity and functional connectivity were computed (network-based statistics, global correlation, integrated local correlation, and fractional amplitude of low-frequency fluctuations) to assess resting-state functional magnetic resonance imaging alterations over the course of AN treatment before and after controlling for underlying GMV.

RESULTS

Patients with acute AN displayed strong and widespread prefrontal, sensorimotor, parietal, temporal, precuneal, and insular reductions of resting-state connectivity and activity. All alterations were independent of GMV and were largely normalized in short-term recovered AN and absent in long-term recovered patients.

CONCLUSIONS

Resting-state functional magnetic resonance imaging alterations in AN constitute acute and GMV-independent, presumably starvation-related, phenomena. The majority of alterations found here normalized over the course of recovery without evidence for possible preexisting trait- or remaining "scar" effects.

Evaluation of spontaneous regional brain activity in weight-recovered anorexia nervosa

Whereas research using structural magnetic resonance imaging (sMRI) reports sizable grey matter reductions in patients suffering from acute anorexia nervosa (AN) to be largely reversible already after short-term weight gain, many task-based and resting-state functional connectivity (RSFC) studies suggest persistent brain alterations even after long-term weight rehabilitation. First investigations into spontaneous regional brain activity using voxel-wise resting-state measures found widespread abnormalities in acute AN, but no studies have compared intrinsic brain activity properties in weight-recovered individuals with a history of AN (recAN) with healthy controls (HCs). SMRI and RSFC data were analysed from a sample of 130 female volunteers: 65 recAN and 65 pairwise age-matched HC. Cortical grey matter thickness was assessed using FreeSurfer software. Fractional amplitude of low-frequency fluctuations (fALFFs), mean-square successive difference (MSSD), regional homogeneity (ReHo), voxel-mirrored homotopic connectivity (VHMC), and degree centrality (DC) were calculated. SMRI and RSFC data were analysed from a sample of 130 female volunteers: 65 recAN and 65 pairwise age-matched HCs. Cortical grey matter thickness was assessed using FreeSurfer software. Fractional amplitude of low-frequency fluctuations (fALFF), mean-square successive difference (MSSD), regional homogeneity (ReHo), voxel-mirrored homotopic connectivity (VHMC), and degree centrality (DC) were calculated. Abnormal regional homogeneity found in acute AN seems to normalize in recAN, supporting assumptions of a state rather than a trait marker. Aberrant fALFF values in the cerebellum and the infertior temporal gyrus could possibly hint towards trait factors or a scar (the latter, e.g., from prolonged periods of undernutrition), warranting further longitudinal research.

Study protocol of comprehensive risk evaluation for anorexia nervosa in twins (CREAT): a study of discordant monozygotic twins with anorexia nervosa

BACKGROUND

Anorexia nervosa (AN) is a severe disorder, for which genetic evidence suggests psychiatric as well as metabolic origins. AN has high somatic and psychiatric comorbidities, broad impact on quality of life, and elevated mortality. Risk factor studies of AN have focused on differences between acutely ill and recovered individuals. Such comparisons often yield ambiguous conclusions, as alterations could reflect different effects depending on the comparison. Whereas differences found in acutely ill patients could reflect state effects that are due to acute starvation or acute disease-specific factors, they could also reflect underlying traits. Observations in recovered individuals could reflect either an underlying trait or a "scar" due to lasting effects of sustained undernutrition and illness. The co-twin control design (i.e., monozygotic [MZ] twins who are discordant for AN and MZ concordant control twin pairs) affords at least partial disambiguation of these effects.

METHODS

Comprehensive Risk Evaluation for Anorexia nervosa in Twins (CREAT) will be the largest and most comprehensive investigation of twins who are discordant for AN to date. CREAT utilizes a co-twin control design that includes endocrinological, neurocognitive, neuroimaging, genomic, and multi-omic approaches coupled with an experimental component that explores the impact of an overnight fast on most measured parameters.

DISCUSSION

The multimodal longitudinal twin assessment of the CREAT study will help to disambiguate state, trait, and "scar" effects, and thereby enable a deeper understanding of the contribution of genetics, epigenetics, cognitive functions, brain structure and function, metabolism, endocrinology, microbiology, and immunology to the etiology and maintenance of AN.

Multimodal neuroimaging in anorexia nervosa

Anorexia nervosa (AN) is a severe and complex psychiatric disorder characterized by intense fear about weight gain and finalized to food-related control behaviors. Growing interest has been demonstrated about neurobiological processes subtend to AN physiopathology. The present review aimed to collect neurostructural and neurofunctional available data from 2010 to 2019. Results have been organized according to the neuroimaging technique employed, also including a specific section on electroencephalographic results, mostly neglected in previous reviews. Diffuse cerebral vulnerability has been demonstrated and the contribution of several structures has been identified. Insula, cingulate cortex, parietal and frontal areas are primarily involved both by structural and functional perspectives. Moreover, consistent alterations in white matter integrity and brain electrical activity have been reported. Neuroimaging findings give a substantial contribution to AN pathophysiological description, also in order to understand altered but reversible processes in the passage from acute illness phase to disorder's remission, useful also for defining therapy.

Abnormal Spontaneous Regional Brain Activity in Young Patients With Anorexia Nervosa

OBJECTIVE

Functional magnetic resonance imaging (fMRI) studies have repeatedly shown alterations in patients with anorexia nervosa (AN). These alterations might be driven by baseline signal characteristics such as the (fractional) amplitude of low frequency fluctuations (fALFF/ALFF), as well as regional signal consistency (ie, regional homogeneity [ReHo]) within circumscribed brain regions. Previous studies have also demonstrated gray matter (pseudo-) atrophy in underweight individuals with AN. Here we study fALFF/ALFF and ReHo in predominantly adolescent patients with AN, while taking gray matter changes into consideration.

METHOD

Resting state fMRI data were acquired from a sample of 148 female volunteers: 74 underweight patients with AN and 74 age-matched female healthy controls (HC).

RESULTS

Group differences for fALFF and ReHo measures were found in several AN-relevant brain regions, including networks related to cognitive control, habit formation, and the ventral visual stream. Furthermore, the magnitude of correlation between gray matter volume/thickness and fALFF and ReHo were reduced in AN compared to HC.

CONCLUSION

Abnormal local resting state characteristics in AN-related brain-networks as well as reduced structure-function relationships may help to explain previously reported task-related and classical resting state neural alterations in underweight AN. Patients with AN may serve as a valuable population for investigating dynamic changes in the relationships between brain structure and function.

Resting-state connectivity within and across neural circuits in anorexia nervosa

INTRODUCTION

Obsessional thoughts and ritualized eating behaviors are characteristic of Anorexia Nervosa (AN), leading to the common suggestion that the illness shares neurobiology with obsessive-compulsive disorder (OCD). Resting-state functional connectivity MRI (rs-fcMRI) is a measure of functional neural architecture. This longitudinal study examined functional connectivity in AN within the limbic cortico-striato-thalamo-cortical (CSTC) loop, as well as in the salience network, the default mode network, and the executive control network (components of the triple network model of psychopathology).

METHODS

Resting-state functional connectivity MRI scans were collected in unmedicated female inpatients with AN (n = 25) and healthy controls (HC; n = 24). Individuals with AN were scanned before and after weight restoration and followed for one month after hospital discharge. HC were scanned twice over the same timeframe.

RESULTS

Using a seed-based correlation approach, individuals with AN had increased connectivity within the limbic CSTC loop when underweight, only. There was no significant association between limbic CSTC connectivity and obsessive-compulsive symptoms or prognosis. Exploratory analyses of functional network connectivity within the triple network model showed reduced connectivity between the salience network and left executive control network among AN relative to HC. These abnormalities persisted following weight restoration.

CONCLUSIONS

The CSTC findings suggest that the neural underpinnings of obsessive-compulsive symptoms may differ from those of OCD. The inter-network abnormalities warrant examination in relation to illness-specific behaviors, namely abnormal eating behavior. This longitudinal study highlights the complexity of the neural underpinnings of AN.

Resting state functional connectivity of networks associated with reward and habit in anorexia nervosa

Neurobiological disturbances associated with reward and/or habit learning are theorized to maintain symptoms of anorexia nervosa (AN). Although research has investigated responses in brain regions associated with reward and habit to disorder-specific cues (e.g., food) and presumed rewards (e.g., money), little is known about the functional organization of the circuits underlying these constructs independent of stimulus. This study aimed to provide initial data on the synchrony of networks associated with reward and habit in AN by comparing resting-state functional connectivity (RSFC) patterns between AN and healthy control (HC) participants in these circuits and delineating how these patterns relate to symptoms. Using theoretically selected seeds in the nucleus accumbens (NAcc), ventral caudate, and dorsal caudate, reflecting a continuum from reward- to habit- oriented regions, RSFC patterns were compared between AN restricting subtype (n = 19) and HC (n = 19) participants (cluster threshold: p < .01). Exploratory correlations between RSFC z-scores and Eating Disorder Examination (EDE) scores, BMI, and illness duration were conducted. The AN group demonstrated lower RSFC between the NAcc and superior frontal gyrus, between the ventral caudate and frontal and posterior regions, and between the dorsal caudate and frontal, temporal, and posterior regions. In the AN group, lower NAcc- superior frontal gyrus RSFC correlated with greater EDE Global scores (r = -.58, CI: -.83, -.13). These resting-state synchrony disruptions of the ventral and dorsal frontostriatal circuits, considered in context of the broader literature, support the utility of further investigating possible reward and habit disturbances supporting symptoms in AN.

An Overview of Conceptualizations of Eating Disorder Recovery, Recent Findings, and Future Directions

PURPOSE OF REVIEW

This review delineates issues in the conceptualization and operationalization of eating disorder recovery, highlights recent findings about recovery (since 2016), and proposes future directions.

RECENT FINDINGS

A longstanding problem in the field is that there are almost as many different definitions of recovery in eating disorders as there are studies on the topic. Yet, there has been a general shift to accepting that psychological/cognitive symptoms are important to recovery in addition to physical and behavioral indices. Further, several operationalizations of recovery have been proposed over the past two decades, and some efforts to validate operationalizations exist. However, this work has had limited impact and uptake, such that the field is suffering from "broken record syndrome," where calls are made for universal definitions time and time again. It is critical that proposed operationalizations be compared empirically to help arrive at a consensus definition and that institutional/organizational support help facilitate this. Themes in recent recovery research include identifying predictors, examining biological/neuropsychological factors, and considering severe and enduring anorexia nervosa. From qualitative research, those who have experienced eating disorders highlight recovery as a journey, as well as factors such as hope, self-acceptance, and benefiting from support from others as integral to the process of recovery. The field urgently needs to implement a universal definition of recovery that is backed by evidence, that can parsimoniously be implemented in clinical practice, and that will lead to greater harmonization of scientific findings.

Altered cerebellar-insular-parietal-cingular subnetwork in adolescents in the earliest stages of anorexia nervosa: a network-based statistic analysis

To date, few functional magnetic resonance imaging (fMRI) studies have explored resting-state functional connectivity (RSFC) in long-lasting anorexia nervosa (AN) patients via graph analysis. The aim of the present study is to investigate, via a graph approach (i.e., the network-based statistic), RSFC in a sample of adolescents at the earliest stages of AN (i.e., AN duration less than 6 months). Resting-state fMRI data was obtained from 15 treatment-naive female adolescents with AN restrictive type (AN-r) in its earliest stages and 15 age-matched healthy female controls. A network-based statistic analysis was used to isolate networks of interconnected nodes that differ between the two groups. Group comparison showed a decreased connectivity in a sub-network of connections encompassing the left and right rostral ACC, left paracentral lobule, left cerebellum (10th sub-division), left posterior insula, left medial fronto-orbital gyrus, and right superior occipital gyrus in AN patients. Results were not associated to alterations in intranodal or global connectivity. No sub-networks with an increased connectivity were identified in AN patients. Our findings suggest that RSFC may be specifically affected at the earliest stages of AN. Considering that the altered sub-network comprises areas mainly involved in somatosensory and interoceptive information and processing and in emotional processes, it could sustain abnormal integration of somatosensory and homeostatic signals, which may explain body image disturbances in AN. Further studies with larger samples and longitudinal designs are needed to confirm our findings and better understand the role and consequences of such functional alterations in AN.

Future Directions for Examination of Brain Networks in Neurodevelopmental Disorders

Neurodevelopmental disorders are associated with atypical development and maturation of brain networks. A recent focus on human connectomics research and the growing popularity of open science initiatives has created the ideal climate in which to make real progress toward understanding the neurobiology of disorders affecting youth. Here we outline future directions for neuroscience researchers examining brain networks in neurodevelopmental disorders, highlighting gaps in the current literature. We emphasize the importance of leveraging large neuroimaging and phenotypic data sets recently made available to the research community, and we suggest specific novel methodological approaches, including analysis of brain dynamics and structural connectivity, that have the potential to produce the greatest clinical insight. Transdiagnostic approaches will also become increasingly necessary as the Research Domain Criteria framework put forth by the National Institute of Mental Health permeates scientific discourse. During this exciting era of big data and increased computational sophistication of analytic tools, the possibilities for significant advancement in understanding neurodevelopmental disorders are limitless.

Study Protocol: Using Deep-Brain Stimulation, Multimodal Neuroimaging and Neuroethics to Understand and Treat Severe Enduring Anorexia Nervosa

BACKGROUND

Research suggests that altered eating and the pursuit of thinness in anorexia nervosa (AN) are, in part, a consequence of aberrant reward circuitry. The neural circuits involved in reward processing and compulsivity overlap significantly, and this has been suggested as a transdiagnostic factor underpinning obsessive compulsive disorder, addictions and eating disorders. The nucleus accumbens (NAcc) is central to both reward processing and compulsivity. In previous studies, deep-brain stimulation (DBS) to the NAcc has been shown to result in neural and symptomatic improvement in both obsessive compulsive disorder and addictions. Moreover, in rats, DBS to the NAcc medial shell increases food intake. We hypothesise that this treatment may be of benefit in severe and enduring anorexia nervosa (SE-AN), but first, feasibility and ethical standards need to be established. The aims of this study are as follows: (1) to provide feasibility and preliminary efficacy data on DBS to the NAcc as a treatment for SE-AN; (2) to assess any subsequent neural changes and (3) to develop a neuroethical gold standard to guide applications of this treatment.

METHOD

This is a longitudinal study of six individuals with SE-AN of >7 years. It includes an integrated neuroethical sub-study. DBS will be applied to the NAcc and we will track the mechanisms underpinning AN using magnetoelectroencephalography, neuropsychological and behavioural measures. Serial measures will be taken on each intensively studied patient, pre- and post-DBS system insertion. This will allow elucidation of the processes involved in symptomatic change over a 15-month period, which includes a double-blind crossover phase of stimulator on/off.

DISCUSSION

Novel, empirical treatments for SE-AN are urgently required due to high morbidity and mortality costs. If feasible and effective, DBS to the NAcc could be game-changing in the management of this condition. A neuroethical gold standard is crucial to optimally underpin such treatment development.

CLINICAL TRIAL REGISTRATION

The study is ongoing and registered with www.ClinicalTrials.gov, https://clinicaltrials.gov/ct2/show/NCT01924598, 22 July, 2013. It has full ethical and HRA approval (Project ID 128658).