Anorexia nervosa and body dysmorphic disorder are associated with abnormalities in processing visual information

Abstract

Background Anorexia nervosa (AN) and body dysmorphic disorder (BDD) are characterized by distorted body image and are frequently comorbid with each other, although their relationship remains little studied. While there is evidence of abnormalities in visual and visuospatial processing in both disorders, no study has directly compared the two. We used two complementary modalities – event-related potentials (ERP) and fMRI – to test for abnormal activity associated with early visual signaling. Methods We acquired fMRI and ERP data in separate sessions from 15 unmedicated individuals in each of three groups (weight-restored AN, BDD, and healthy controls) while they viewed images of faces and houses of different spatial frequencies. We used joint independent component analyses to compare activity in visual systems. Results AN and BDD groups demonstrated similar hypoactivity in early secondary visual processing regions and the dorsal visual stream when viewing low spatial frequency faces, linked to the N170 component, as well as in early secondary visual processing regions when viewing low spatial frequency houses, linked to the P100 component. Additionally, the BDD group exhibited hyperactivity in fusiform cortex when viewing high spatial frequency houses, linked to the N170 component. Greater activity in this component was associated with lower attractiveness ratings of faces. Conclusions Results provide preliminary evidence of similar abnormal spatio-temporal activation in AN and BDD for configural/holistic information for appearance- and nonappearance-related stimuli. This suggests a common phenotype of abnormal early visual system functioning, which may contribute to perceptual distortions.

Appearance evaluation of others' faces and bodies in anorexia nervosa and body dysmorphic disorder

“…Previous brain imaging studies in BDD have shown aberrant patterns of hypoactivation in visual systems for low detail (LSF) images of own face, familiar face, and object stimuli . As mentioned above, a study that included AN and BDD showed that both groups, compared to HC, displayed hypoactivity in the dorsal ventral stream and early secondary visual processing regions when viewing LSF faces . While future studies will be required to investigate this, these results may reflect common, diminished global and holistic information processing, uncovered by the same LSF image “probes” as in the current study, which could contribute to facial perception that is lower in attractiveness.…”

“…Thus, AN and BDD exhibit similar abnormalities in appearance valuations that extend beyond themselves to others' appearance, and for physical features that are related and unrelated to their primary appearance concern. Our recent imaging data (the results of which were available only after we had formulated hypotheses and conducted the current study) might suggest that the neural underpinnings of this finding could be related to a common abnormality in visual processing of emotion‐neutral stimuli, but this idea should be considered with circumspection given that we did not directly measure neural responses in this study.…”

“…In addition, future studies using neuroimaging could test for abnormalities associated with appearance judgments and self‐referential thinking that may occur while viewing faces and bodies in BDD and AN, to provide an understanding of the neurobiological processes underlying these phenomena. Another promising avenue of research is in applying perceptual retraining techniques to correct/re‐adjust proposed abnormalities in visual information processing pathways …”

“…17 High-pass filtered, or "high spatial frequency" images convey information about contours, edges, and texture, and thus represent fine-grained details whereas low spatial frequency images convey lowgrained, configural, and holistic elements. [18][19][20] In a previous fMRI study, we found that brain activation for high spatial frequency images was inversely associated with how attractive individuals with BDD rated others' faces, 21 perhaps suggesting a neural process that links greater detail extraction by the visual system to reduced perceived attractiveness of facial characteristics. This proposal is corroborated by previous studies by other investigators that have found lower visual preference for high or low spatial frequencies.…”

Brain connectome modularity in weight-restored anorexia nervosa and body dysmorphic disorder

“…Three recent studies have compared their neurobiology related to brain activation and connectivity in response to visual stimuli (Li et al 2015a; Li et al 2015b; Moody et al 2015), but none have investigated their brain structural connectome using state-of-the-art analytics of modularity analysis. To explore similarities and differences in brain connectivity, we analyzed whole-brain tractography-derived networks (i.e., structural connectomes) using graph theory, which quantifies complex networks or “graphs” to provide information about their organizational properties.…”