Dynamic reconfigurations of brain subnetworks in female patients with alcohol use disorder or bulimia nervosa: a resting-state functional magnetic resonance imaging study.

Introduction: The brain forms a complex functional brain network. This network is dynamically reconfigured to support various cognitive processes. Research on brain network dynamics in patients with alcohol use disorder (AUD) or bulimia nervosa (BN), two highly comorbid psychiatric disorders, remains limited. Previous studies showed altered static network patterns, highlighting that the network is disturbed, but implicitly ignoring network dynamics. This study investigates dynamic network reconfigurations in female patients with AUD or BN and healthy controls (HC).

Methods: Resting-state functional MRI data were acquired of 102 female participants (AUD:27, BN:24, HC:51). A sliding-window approach assigned brain regions iteratively to one of seven literature-based subnetworks for each window. Then, previously validated parameters of network reconfiguration were assessed: promiscuity (number of subnetworks switched to) and flexibility (number of switches). These measures were compared between groups and related to behavioral and clinical measures.

Results: Compared to HC, patients with BN displayed a higher promiscuity of all brain subnetworks combined, and regionally for the dorsal attention network, with no change in flexibility. Patients with AUD showed no difference in either promiscuity or flexibility. Global and dorsal attention network promiscuity were negatively correlated with subjective stress.

Conclusion: Regions typically assigned to the dorsal attention network changed their association with a higher number of other subnetworks in BN compared to HC, which was not seen in AUD. This suggests a less focused dynamic integration of information in patients with BN, which could play a role in their vulnerability to stress, attentional biases and impulsivity.