Volume and complexity of the thalamus in Anorexia Nervosa: An exploratory evaluation

Objective: Recent neuroscientific findings have highlighted the role of the thalamus in several cognitive functions, ranging from perception to cognitive flexibility, memory, and body representation. Since some of these functions may be involved in the pathophysiology of Anorexia Nervosa (AN), this study aims at exploring thalamic structure in different phases of the disorder. Method: The sample included 38 patients with acute AN, 20 patients who fully recovered from AN (recAN), and 38 healthy controls (HC), all female. All participants underwent high-resolution MRI. The volumes of the whole thalamus and 25 thalamic nuclei were extracted using an automated segmentation algorithm, and thalamic fractal dimension was estimated using the calcFD toolbox. Results: Patients with acute AN, compared to HC, displayed reduced thalamic volume and complexity both at the whole level and at the level of specific nuclei. In patients recAN, instead, alterations were observed only at the level of the right laterodorsal and central lateral nuclei. Conclusions: In the acute phase of the disorder patients with AN present a widespread reduction in thalamic volume and complexity. However, these alterations seem to normalise almost completely following weight restoration, thus suggesting the involvement of malnutrition-related mechanisms.