There is considerable evidence to suggest that individuals with bulimia nervosa (BN) exhibit deficits in self- regulatory control. The brain regios involved in these processes have been identified by functional magnetic resonance imaging (fMRI) studies. However, research directly linking self-regulatory deficits and neural activity to clinically meaningful behaviors in BN is notably lacking, largely because motion artifact precludes measurement with fMRI of neural activity during participant-initiated eating. The proposed Ruth L. Kirschstein National Research Service Award (NRSA) is a two-year program of research and training focused on the neural systems mediating general and eating-related self-regulatory control processes in BN. Functional near- infrared spectroscopy (fNIR), a portable and inexpensive neuroimaging modality, allows for assessment of cortical activity in more ecologically- and clinically-valid settings. The proposed project will examine brain activity during a standard and an eating-related go/no-go task in 35 women meeting provisional DSM-5 diagnostic criteria for BN and 35 matched healthy controls. The project aims first to confirm and cross-validate previous findings. This will include testing the hypotheses that 1) compared to healthy controls, women with BN will demonstrate impaired performance and reduced prefrontal neural activity (as measured by fNIR) during the inhibition of prepotent responses in a standard go/no-go task;2) among women with BN, the magnitude of activity in prefrontal regions will correlate inversely with self-reported frequency of bulimic behaviors. In a subset of participants (n = 28), the fNIR data for this standard task will be cross-validated using fMRI. The study then aims to extend findings using a novel, go/no-go liquid-meal sipping task and a palatable yogurt shake. The same hypotheses will be tested during this second go/no-go task, which requires inhibition of a prepotent sipping response during "no-go" trials. The results of the proposed study would not only confirm the importance of deficits in prefrontal activation during response inhibition tasks in BN, but extend these previous findings by demonstrating similar, and perhaps more profound, deficiencies in activity during a behavioral task that requires self-regulatory control during eating. Importantly, unlike previous studies that have included only symptom-provocation tasks or general cognitive neuroscience paradigms, the combination of aims allows for distinction of activations related specifically to the inhibition of eating from those related o general response inhibition. This NRSA will provide the applicant with the skills and research experience needed to integrate imaging and behavioral data in the investigation of the neural substrates of BN. The novel integration of neuroimaging with a cognitive neuroscience paradigm and an eating task will elucidate the neurobehavioral connections associated with binge eating and the prefrontal neural mechanisms that may contribute to the development and maintenance of the disorder.
While considerable evidence suggests that individuals with bulimia nervosa (BN) struggle with self-regulation, no research to date has directly linked brain activity, self-regulatory deficits, and clinically meaningful behaviors in this chronic and increasingly prevalent psychiatric disorder. The proposed study will be the first to measure brain activity among women with and without BN during both general and eating-related self-regulatory control tasks. The results will allow us to better determine whether altered activity in the prefrontal regions that mediate self-regulatory processes is specific to bulimic pathology.
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