Functional brain imaging of human hunger and satiety
Dr. Michael Farrell
Email: m.farrell(at)hfi.unimelb.edu.au
This project is a collaboration between the Howard Florey Institute, the Centre for Neuroscience and the Centre for Obesity Research and Education (CORE).
Obesity is a major public health problem. The predominant cause of obesity is eating in excess of daily energy requirements. The conscious experiences of hunger and satiety are associated with activity in cortical and subcortical structures. Brain activity associated with hunger has divergent patterns in obese people compared to lean people.
Many questions regarding the implications of brain imaging studies in the obese are yet to be addressed. This uncertainty stems from inherent difficulties with interpretation of measurements from the fully integrated human brain. Further advances in our understanding of the cortical correlates of obesity will depend on the development of suitable paradigms for the manipulation of hunger and satiety in normal and obese samples.
This project will benefit from a unique opportunity to manipulate hunger in a group of lap band patients with obesity. The lap band is a surgically implanted device that reduces sensations of hunger, enhances satiety after ingestion of food and facilitates weight loss. Changing the pressure exerted by the hydraulic sleeve in the lap band on the esophageal-gastric juncture is a simple, non-invasive procedure, which makes it ideal for functional brain imaging experiments. The versatility afforded by the lap band does not obviate the need to image relatively stable states, a situation that has previously precluded the use of functional Magnetic Resonance Imaging (fMRI).
The project will utilize a cutting edge fMRI imaging sequence to collect cerebral blood flow measures that are resistant to the low frequency artifacts that have thus far precluded blood oxygen level-dependent (BOLD) measures for the investigation of hunger.