Recent evidence suggests that impairments in self-regulatory control may contribute to the development and persistence of bulimia nervosa (BN). Loss of control over eating and compensatory behaviors in BN may result, in part, from deficits in inhibitory control and associated brain-based dysfunction in corticostriatal circuits. In additin, recent models of BN pathology suggest that impairments in self-regulation of emotion may relate to disorder-specific behaviors. Deficits in the ability to exert self-regulatory control may also allow repeated binge eating and purging to become an entrenched behavioral pattern. Identification and characterization of brain-based abnormalities in BN, which could inform novel interventions that target these abnormalities, is imperative. A main objective of the National Institute of Mental Health Strategic Plan includes promoting discovery of brain-behavior processes that contribute to mental illness. Consistent with this strategic objective and the need to develop new and targeted treatments for BN, the proposed Ruth L. Kirschstein National Research Service Award (NRSA) is a three-year program of research and training focused on the overlapping corticostriatal neural circuits mediating multiple self-regulatory capacities in adult BN. Prior studies of control-related deficits in BN have been limited by their use of a singl task to study a single neurocognitive process. The proposed study assesses, among women with BN (n = 30) and group-matched controls (n = 30), the behavioral and neural determinants of three forms of self-regulation (motor inhibition, emotion regulation, and goal-directed action control) and examines relations among these capacities and BN symptoms. The project combines functional magnetic resonance imaging (fMRI), eating disorder symptom assessment, and well-validated neurocognitive tasks. The project aims to test the hypotheses that: 1) women with BN will demonstrate decreased corticostriatal activation and impaired performance during motor inhibitory control and emotion regulation tasks, 2) women with BN will demonstrate deficient goal-directed control abilities, and 3) BN participants with more severe symptoms will demonstrate the greatest impairments in corticostriatal activation, and a model including self-regulatory abilities in all three domains will best predict BN severity. To our knowledge, this project is the first to examine brain activation during negative and positive emotion regulation in BN and the first to investigate a potential relative imbalance in goal-directed control and habit-based responding in BN. This NRSA will lay groundwork for future investigations of the neural substrates of eating disorders by providing the applicant with the advanced skills and research experience needed to collect, analyze, and interpret fMRI and behavioral data, along with introductory training in neurodevelopment. The project's novel integration of multiple, non-symptom-specific probes of motor, affective, and goal-directed behavioral control within the same sample permits distinction of the relative contributions of these self- regulatory control capacities to BN pathology.
Bulimia nervosa (BN), a chronic, debilitating, and increasingly prevalent psychiatric disorder, has been linked to impairments in the ability to control behaviors and emotions. The proposed study will be the first to investigate brain activation and performance associated with multiple forms of self-regulation in women with BN. Characterization of dysfunction in the brain circuits that underlie self-regulatory control and assessment of its relation to BN symptoms are consistent with NIMH's strategic plan, and results could inform novel treatments for eating disorders characterized by behavioral and emotional dyscontrol.
