"Locked in my body, caught up in my mind": Neural signatures of body image rumination in anorexia nervosa.

OBJECTIVES

Body image is a multidimensional construct crucial to the development and maintenance of anorexia nervosa (AN). Cognitive-emotional mechanisms shaping body image, particularly AN patients' tendency to ruminate, remain insufficiently understood. This study investigated body-focused rumination using a novel functional magnetic resonance imaging (fMRI) Rumination Induction task.

METHODS

Patients (n = 18) and healthy controls (n = 19) completed baseline assessments of rumination, body appreciation, and clinical measures. During fMRI, participants engaged in a task with self- and body-focused prompts contrasted with a neutral condition. Emotional valence and intensity were assessed pre- and post-task, alongside task-specific self-report ratings of affective valence and rumination experience. Whole-brain activations were examined for the main contrast (rumination vs. neutral) and, exploratorily, for early versus late rumination phases.

RESULTS

Compared to controls, patients showed reduced activation in default mode network (DMN) overlapping regions, encompassing perigenual cingulate cortex, lateral parietal and temporal regions, praecuneus, temporoparietal junction, and cerebellum. A decreased engagement of the ventrolateral prefrontal cortex-key frontoparietal network node-in AN during early versus late rumination phases is outlined.

CONCLUSIONS

Reduced DMN hubs activation may reflect disrupted cognitive-affective, autobiographical, and social mentalization processes in AN, as elicited by self-centred cognitions. At the same time, decreased ventrolateral prefrontal activity may suggest diminished ability to initiate affective reappraisal of self-focused cognitions, limiting voluntary suppression of repetitive thoughts in early versus later rumination stages. Overall, these findings support a model in which body image distortions are sustained by maladaptive cognitive-emotional mechanisms, whose neuronal markers may be highlighted through rumination predisposition.