The Laboratory of Neuroimaging uses a variety of imaging and cognitive techniques to study five areas of neurobiological interest. The first area involves questions about molecular changes associated with addictive disorders. For example, the Laboratory has shown that cocaine abusers increase metabolic activity in the fronto-accumbal region of the brain when they are shown cocaine-related images and told to control their cravings; that methylphenidate blunts limbic inhibition when cocaine abusers are shown cocaine-related videos; and that methamphetamine accumulates in the lungs, liver, brain and kidneys, but lung accumulation in African Americans is higher than lung accumulation in Caucasians. The second study area involves questions about the use of stimulant drugs for psychiatric therapies. The Laboratory’s work in this area has shown that, contrary to common assumptions, modafinil (a wake-promoting drug) has a high potential for abuse because it blocks dopamine transporters and increases dopamine concentrations in the brain; that stimulant medications for attention deficit hyperactivity disorder (ADHD) probably work by blocking dopamine transporters and increasing dopamine concentrations in the default mode network of the brain; and that methylphenidate increases cognitive abilities by activating the brain’s dorsal attention network and deactivating the default mode network. The Laboratory’s third area of investigation examines the role of dopamine in the manifestation of ADHD. For example, the Section has demonstrated that, compared with control subjects, ADHD patients show decreased dopamine concentrations in the hypothalamus and lower scores on cognitive tests of motivation. This suggests that the disorder’s characteristic motivation deficits are connected to the dopamine reward system. The Laboratory’s fourth area of inquiry relates to questions about the neurological determinants of obesity. For example, the Laboratory has shown that body mass index(BMI) scores were inversely proportional to glucose metabolism in prefrontal brain regions, as well as cognitive tests of memory and executive function; and that BMI was inversely proportional to activation in dopaminergic and serotonergic brain regions, but directly proportional to activation in the posterior insula and cerebellum, during gastric distention (i.e., the expansion of the stomach after eating). The Laboratory’s final area of investigation focuses on techniques used to study normal brain functions. For example, the Laboratory has shown that echo planar imaging artificially decreases neuronal activity at the poles of the brain, and the Laboratory has developed a technique for rapidly mapping the distribution of hubs in the human brain.

LNI is currently looking for an enthusiastic post-doctoral chemist to work on neuroimaging probe development towards medical applications for PET. Experience in small molecule synthesis/medicinal chemistry or radiochemistry or organometallic chemistry or bioorganic chemistry would be preferable, but not a requirement (Contact sunny.kim@nih.gov).

http://fic.nih.gov/Programs/Pages/korea-biomed-fellowship.aspx