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The human brain possesses a unique ability to switch between patterns of functional connectivity, known as brain states, which are crucial for regulating biological, cognitive, and emotional processes. These states have been linked to numerous neurological and neuropsychiatric conditions, but their relationship to the clinical symptoms of anorexia nervosa (AN) is not well understood. In this exploratory study, we aimed to identify whole-brain dynamic functional connectivity alterations in AN and their potential association with AN symptoms.
To this end, we recruited 19 women diagnosed with AN and 22 age- and gender-matched healthy controls (HCs) who underwent resting-state functional magnetic resonance imaging (rs-fMRI). We adopt a sliding-window approach to estimate and characterize functional brain states, a methodology previously validated in our AN dynamic connectivity study of the central autonomic network (de la Cruz et al., 2023). Specifically, we split rs-fMRI time series into 60-seconds sliding time windows, with the onset of each window progressively shifted by 20 seconds from that of the previous window. This window configuration, with a size of 60 seconds and an overlap of 40 seconds, strikes a balance between sensitivity in detecting potentially meaningful fluctuations in functional connectivity and maintaining a favorable signal-to-noise ratio. In addition to rs-fMRI, participants completed several questionnaires assessing general psychopathology, including the Eating Disorder Inventory-2, the State–Trait Anxiety Inventory, Toronto Alexithymia Scale, and the Beck Depression Inventory.
Utilizing the sliding-window approach, our analysis revealed that AN patients exhibited limited flexibility in transitioning between different brain configurations compared to HCs. Furthermore, we observed that AN patients spent a significant amount of time in a functional brain state characterized by a strong coupling between the ventral attentional and somatomotor networks. These networks are known to play a pivotal role in AN traits such as body image disturbances, altered interoceptive awareness, and dysfunctional processing of bodily signaling and body image-body schema interaction. Notably, the duration spent in this specific brain state showed a negative correlation with body mass index and a positive correlation with eating disorder scales, highlighting the maladaptive nature of this functional brain configuration in AN.
In summary, our study underscores the potential of dynamic functional connectivity as a diagnostic and therapeutic marker for AN, offering valuable insights into the underlying neurobiological mechanisms of the disorder.
Zagha E, McCormick DA. Neural control of brain state. Curr Opin Neurobiol. 2014 Dec;29:178-86.
de la Cruz, F., Schumann, A., Suttkus, S., Helbing, N., & Bär, K.-J. (2023). Dynamic changes in the central autonomic network of patients with anorexia nervosa. European Journal of Neuroscience, 57(9), 1597–1610.
