Principal Investigator: Amanda Bruce, PhD
"Food for thought: Can stomach surgery change the brain?"
While bariatric surgery is an effective long-term treatment for obesity, the physiological mechanisms associated with successful surgery are not well understood. Researchers have hypothesized that, following food consumption, surgical modifications elicit hormonal and neural signals that trigger feelings of satiety in the brain. Our group recently examined the association between weight loss and brain function using two separate patient-groups. In the first fMRI study, we scanned participants before and 12 weeks after receiving laparoscopic adjustable gastric banding (LAGB) surgery. In a second study, using the same neuroimaging protocol, we scanned participants prior to and 12-weeks following a behavioral weight loss intervention.
We now intend to directly compare participants from these two studies. In this project, we will
1. Characterize cortical differences at baseline, examining brain responses to visual food cues in limbic, paralimbic, and prefrontal brain regions.
2. Identify behavioral changes associated with bariatric surgery including self-reported hunger and cognitive control.
3. Examine longitudinal cortical changes associated with bariatric surgery in paralimbic, limbic, and prefrontal brain regions.
This would be the first project to examine the effects of bariatric surgery on brain physiology in comparison to a behavioral weight loss intervention. The findings from this research can improve our understanding of successful long-term weight loss and open additional avenues for new behavioral and pharmacological weight loss interventions.
Principal Investigator: Jennifer Lundgren, PhD
“Functional Neuroanatomy of Impulsivity in Obese Shorter and Longer Sleepers”
The long-term objective of this project is to understand better the relationship between sleep and obesity and, consequently, improve obesity treatment and prevention efforts. Although a relationship between sleep duration and obesity has been established, potential mechanisms by which sleep loss can lead to the development of obesity have not been adequately explored. One potential mechanism by which shorter sleep could contribute to obesity is through its detrimental effect on executive functioning, and impulsivity in particular. The aim of this project, therefore, is to examine the neural systems involved in impulse control using functional magnetic resonance imaging (fMRI) and a delay discounting paradigm in obese participants with shorter (<5 hours) and longer (7-8 hours) sleep duration. Obese shorter sleepers and obese longer sleepers, with actigraphy confirmed sleep duration, will complete behavioral assessments of eating, sleep, and impulsivity as well as complete a computerized delay discounting of reward paradigm while undergoing fMRI. Shorter and longer sleep groups will be compared on delay discounting of reward choices and neural activation in the limbic, paralimbic, and lateral prefrontal regions of the brain while engaging in the delay discounting task. Behavioral measures will be correlated with activity in these brain regions during the delay discounting task.
