Brain functional alterations in patients with anorexia nervosa: A meta-analysis of task-based functional MRI studies

The goal of this study was to discern the neural activation patterns associated with anorexia nervosa (AN) in response to tasks related to body-, food-, emotional-, cognitive-, and reward- processing. A meta-analysis was performed on task-based fMRI studies, revealing that patients with AN showed increased activity in the left superior temporal gyrus and bilaterally in the ACC during a reward-related task. During cognitive-related tasks, patients with AN also showed increased activity in the left superior parietal gyrus, right middle temporal gyrus, but decreased activity in the MCC. Additionally, patients with AN showed increased activity bilaterally in the cerebellum, MCC, and decreased activity bilaterally in the bilateral precuneus/PCC, right middle temporal gyrus, left ACC when they viewed food images. During emotion-related tasks, patients with AN showed increased activity in the left cerebellum, but decreased activity bilaterally in the striatum, right mPFC, and right superior parietal gyrus. Patients with AN also showed increased activity in the right striatum and decreased activity in the right inferior temporal gyrus and bilaterally in the mPFC during body-related tasks. The present meta-analysis provides a comprehensive overview of the patterns of brain activity evoked by task stimuli, thereby augmenting the current comprehension of the pathophysiology in AN.

Body Processing in Children and Adolescents with Traumatic Brain Injury: An Exploratory Study

Dysfunctions in body processing have been documented in adults with brain damage, while limited information is available for children. This study aimed to investigate body processing in children and adolescents with traumatic brain injury (TBI) (N = 33), compared to peers with typical development. Two well-known computerized body-representation paradigms, namely Visual Body Recognition and Visuo-spatial Imagery, were administered. Through the first paradigm, the body inversion and composite illusion effects were tested with a matching to sample task as measures of configural and holistic processing of others’ bodies, respectively. The second paradigm investigated with a laterality judgement task the ability to perform first-person and object-based mental spatial transformations of own body and external objects, respectively. Body stimuli did not convey any emotional contents or symbolic meanings. Patients with TBI had difficulties with mental transformations of both body and object stimuli, displaying deficits in motor and visual imagery abilities, not limited to body processing. Therefore, cognitive rehabilitation of body processing in TBI might benefit from the inclusion of both general training on visuo-spatial abilities and specific exercises aimed at boosting visual body perception and motor imagery.

Brain activation and connectivity in anorexia nervosa and body dysmorphic disorder when viewing bodies: relationships to clinical symptoms and perception of appearance

Anorexia nervosa (AN) and body dysmorphic disorder (BDD) are characterized by distorted perception of appearance, yet no studies have directly compared the neurobiology associated with body perception. We compared AN and BDD in brain activation and connectivity in relevant networks when viewing images of others' bodies and tested their relationships with clinical symptoms and subjective appearance evaluations. We acquired fMRI data from 64 unmedicated females (20 weight-restored AN, 23 BDD, 21 controls) during a matching task using unaltered or spatial-frequency filtered photos of others' bodies. Using general linear model and independent components analyses we compared brain activation and connectivity in visual, striatal, and parietal networks and performed univariate and partial least squares multivariate analyses to investigate relationships with clinical symptoms and appearance evaluations. AN and BDD showed partially overlapping patterns of hyperconnectivity in the dorsal visual network and hypoconnectivity in parietal network compared with controls. BDD, but not AN, demonstrated hypoactivity in dorsal visual and parietal networks compared to controls. Further, there were significant activity and connectivity differences between AN and BDD in both networks. In both groups, activity and/or connectivity were associated with symptom severity and appearance ratings of others' bodies. Thus, AN and BDD demonstrate both distinct and partially-overlapping aberrant neural phenotypes involved in body processing and visually encoding global features. Nevertheless, in each disorder, aberrant activity and connectivity show relationships to clinically relevant symptoms and subjective perception. These results have implications for understanding distinct and shared pathophysiology underlying perceptual distortions of appearance and may inform future novel treatment strategies.

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.

Iowa Gambling Task and Distortion in Perception of Body Image Among Adolescent Women With Eating Disorders

The Iowa gambling task (IGT) is an instrument for the neuropsychological evaluation of cognitive and emotional decision making (DM) processes that was created to test the somatic marker hypothesis (SMH) described by Damasio in 1994. It was initially applied to patients with frontal lobe lesions due to its association with executive functions but was subsequently used on patients with a variety of disorders. Although the DM process is inherently perceptual, few studies have applied the IGT to examine DM processes in patients with eating disorders (EDs), and even fewer have associated the IGT to the perceptual distortion of body image (PDBI) in this population. People diagnosed with ED exhibit heightened control over their somatic responses-for example, they can delay digestion for hours-and DM may be affected in this condition. This study compares the performance of two samples of adolescent women-hospitalized patients with ED, and healthy controls with similar demographic characteristics-on the IGT using body image as a possible factor in the SMH. Seventy-four women with a mean age of 14.97 years (SD = 2.347) participated. To analyze their body self-image, we used the figure-rating scale and compared the results with their body mass index (BMI). Correlations between indices of the IGT and distortion in body image were then explored. The results revealed significant differences between the groups in terms of evolving performance on the partial IGT. Patients with ED performed worse than their healthy counterparts in the last 40 trials and exhibited greater distortions in their body image, especially in terms of overestimation. Indices of these distortions were negatively correlated with the total IGT. These results are compatible with the SMH because they suggest that patients with ED evinced blindness with regard to the future, as described by their authors. In addition, a negative correlation was found between the IGT and PDBI, showing that a more distorted body image was associated with lower IGT, that is, more disadvantageous or riskier decisions were made by the subjects with more distortion.

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.

Distinct neural response to visual perspective and body size in the extrastriate body area

Neuroimaging research has independently implicated the extrastriate body area (EBA) in distinguishing between different visual perspectives and morphologies of bodies within visual processing. However, the combined processing of these physical attributes towards neural EBA response remains unclear, and may be crucial in influencing higher-order, aesthetic evaluation of bodies. Indeed, EBA alterations amongst eating disorder patients have been associated with disturbances in body image, and disruption to EBA activity amongst healthy individuals has been shown to influence aesthetic evaluations made towards bodies. Therefore, the present study used images of slim and large female bodies viewed from egocentric and allocentric perspectives, to investigate neural EBA response amongst healthy females (N = 30). In addition, participants provided behavioural aesthetic and weight evaluations of all model stimuli. Results revealed an interaction, bilaterally, between visual perspective and body size towards EBA activity, with multi-voxel pattern analysis revealing distinct neural patterns between the four conditions. However, EBA activity did not relate to non-clinical eating disorder psychopathology. No direct relationship was found between EBA activity and behavioural evaluations of model stimuli; however, a whole brain analysis revealed that higher-order, prefrontal regions were associated with cognitive evaluations of large bodies. Taken together, our results suggest that the EBA is an integral core region in discriminating between multiple physical attributes of the body, which is likely to provide important information to higher-order brain regions which make aesthetic evaluations towards bodies.

Evidence for altered configural body processing in women at risk of disorders characterized by body image disturbance

Two studies were conducted to assess appearance-related visual processing mechanisms in populations at risk of disorders characterized by body image disturbance. Using inverted stimuli, Experiment 1 assessed visual processing mechanisms associated with body, face, and house viewing in adolescents. Experiment 2 applied the same protocol to assess appearance-related configural processing in high- and low-risk adolescent women, and women recovering from disorders characterized by body image disturbance. Experiment 1 found evidence for typical configural face and body processing, although adolescent women reported higher levels of body image concern (BIC) and self-objectified to a greater extent than adolescent men. In Experiment 2, typical body inversion effects were seen in the low-risk group, whilst there was some evidence to suggest a disruption to the configural processing of body stimuli in high-risk adolescents and in women recovering from body image disorders. Women in recovery were also quicker to respond to all stimuli, whilst high-risk adolescents took longer to respond to bodies than to other stimuli. Configural face processing was intact in all groups, and effects did not directly relate to BIC or self-objectification. These findings have implications for future research looking to inform early interventions and treatment, suggesting that there could be a tendency to visually process individual body parts at the expense of the whole-body form in women at risk of developing body image disorders, as well as those in recovery.

Sustained hypervigilance for one's own body in women with weight and shape concerns: Competition effects in early visual processing investigated by steady-state visual evoked potentials (SSVEP)

This study aimed to analyze the covert attentional time course in early body processing areas in women with high body concerns. Therefore, we assessed the effect of pictures of one's own body and other bodies as distractions from a demanding dot detection task in 24 women with low and 20 women with high body concerns. Participants were instructed to attend to flickering dots eliciting steady-state visual evoked potentials (SSVEP) measured by EEG. Both groups showed a sustained SSVEP amplitude reduction, which was more pronounced for average-weight or thin bodies than for overweight bodies. For women with high body concerns, SSVEP amplitudes decreased more in the case of pictures of their own body. The results indicate covert vigilance and maintenance patterns for body stimuli, especially for bodies representing the thin ideal. Moreover, women with high body concerns attend more to information about their own body, which might maintain body dissatisfaction.

Conceptualizing body dissatisfaction in eating disorders within a self-discrepancy framework: a review of evidence

Body dissatisfaction, the negative subjective evaluation of one's body, is associated with many negative psychological and physical health consequences. One conceptualization of body dissatisfaction includes an experience of discrepancy between perceived actual and ideal body shapes. This paper reviews the literature on three facets of body dissatisfaction from the framework of self-discrepancy theory: perceptions of current weight, ideal body weight, and the relative importance of conforming to ideals. We review components of body dissatisfaction among healthy individuals and eating-disordered individuals. We also address the conceptualization's relationship among body dissatisfaction, weight history, and dieting to expand the impact of body dissatisfaction research and to provide more information on the nature and treatment of eating disorders.

Neurobiology of Anorexia Nervosa: Serotonin Dysfunctions Link Self-Starvation with Body Image Disturbances through an Impaired Body Memory

The etiology of anorexia nervosa (AN) is still unclear, despite that it is a critical and potentially mortal illness. A recent neurobiological model considers AN as the outcome of dysfunctions in the neuronal processes related to appetite and emotionality (Kaye et al., 2009, 2013). However, this model still is not able to answer a critical question: What is behind body image disturbances (BIDs) in AN? The article starts its analysis from reviewing some of the studies exploring the effects of the serotonin systems in memory (episodic, working, and spatial) and its dysfunctions. The review suggests that serotonin disturbances may: (a) facilitate the encoding of third person (allocentric) episodic memories; (b) facilitate the consolidation of emotional episodic memories (e.g., teasing), if preceded by repeated stress; (c) reduce voluntary inhibition of mnestic contents; (d) impair allocentric spatial memory. If we discuss these results within the interpretative frame suggested by the “Allocentric Lock Hypothesis” (Riva, 2012, 2014), we can hypothesize that altered serotoninergic activity in AN patients: (i) improves their ability to store and consolidate negative autobiographical memories, including those of their body, in allocentric perspective; (ii) impairs their ability to trigger voluntary inhibition of the previously stored negative memory of the body; (iii) impairs their capacity to retrieve/update allocentric information. Taken together, these points suggest a possible link between serotonin dysfunctions, memory impairments and BIDs: the impossibility of updating a disturbed body memory using real time experiential data—I'm locked to a wrong body stored in long term memory—pushes AN patients to control body weight and shape even when underweight.

Altered social attention in anorexia nervosa during real social interaction

The capacity to devote attentional resources in response to body-related signals provided by others is still largely unexplored in individuals with Anorexia Nervosa (AN). Here, we tested this capacity through a novel paradigm that mimics a social interaction with a real partner. Healthy individuals (Experiment 1) and individuals with AN (Experiment 2) completed a task with another person which consisted in performing, alternatively, rapid aiming movements to lateralised targets. Generally, this task leads to a form of Inhibition of Return (IOR), which consists of longer reaction times when an individual has to respond to a location previously searched by either himself (individual IOR) or by the partner (social IOR) as compared to previously unexplored locations. IOR is considered as an important attentional mechanism that promotes an effective exploration of the environment during social interaction. Here, healthy individuals displayed both individual and social IOR that were both reliable and of the same magnitude. Individuals with AN displayed a non-significant individual IOR but a reliable social IOR that was also significantly stronger than individual IOR. These results suggest the presence of a reduced sensitivity in processing body-related stimuli conveyed by oneself in individuals with AN which is reflected in action-based attentional processes.

Altered orienting of attention in anorexia nervosa

The study of cognitive processes in anorexia nervosa (AN) is largely unexplored, although recent evidence suggests the presence of impairments in both social cognition and attention processing. Here we investigated AN patients' ability to orient attention in response to social and symbolic visual stimuli. AN patients and matched controls performed a task in which gaze and pointing gestures acted as social directional cues for spatial attention. Arrows were also included as symbolic cue. On each trial, a centrally-placed cue appeared oriented rightwards or leftwards. After either 200 or 700ms, a lateralized neutral target (a letter) requiring a discrimination response appeared in a location either spatially congruent or incongruent with the directional cue. Controls showed a reliable orienting irrespective of both temporal interval and cue type. AN patients showed a reliable orienting at both temporal intervals only in response to pointing gestures. Both gaze and arrow cues failed to orient attention at the short temporal interval, that is when attention is under reflexive control, whereas a reliable orienting emerged at the long temporal interval. These results provide preliminary evidence of altered reflexive orienting of attention in AN patients that does not extend to body-related cues such as pointing gestures.