Obesity and the brain: structural and functional imaging studies, and opportunities for large-scale imaging genetics

Obesity has increasingly been recognized as a precursor of negative health outcomes including increased risk of dementia and accelerated cognitive decline. With the increase of sample sizes of population-based imaging studies, there is a growing level of evidence of changes in brain structure in obesity, such as brain atrophy and loss of white matter integrity. Functional imaging studies using positron emission tomography have highlighted the similarities between behavioral responses and dopaminergic pathways that regulate neuronal systems in both addiction and obesity. Functional magnetic resonance imaging studies have increasingly been applied to study the brain insulin sensitivity. Combining large-scale population-based imaging data with genotype data leads to new opportunities that enable the possibility to study brain differences in obesity and relate these to possible underlying genetic and molecular pathways. This chapter provides an overview of the existing literature of obesity in relation to the brain, and discusses findings and opportunities of imaging genetic studies to unravel underlying neurobiological pathways.