Professor Mark D'Esposito

Department of Psychology and Helen Wills Neuroscience Institute

Dr. D'Esposito's research focuses on the neural bases of high-level cognitive processes such as working memory and executive control. A major emphasis of his research is to understand the neural mechanisms of age-related decline in these cognitive processes. These research aims are achieved through several different experimental approaches and methodologies. First, Dr. D'Esposito's laboratory employs a neuroimaging method called functional Magnetic Resonance Imaging (MRI) to identify the neuroanatomical substrates and temporal dynamics of various cognitive processes in normal human subjects throughout the lifespan. Of key focus are the cognitive functions supported by the frontal lobes, which have been shown to exhibit greater age-related changes than other areas of the brain. Second, the lab investigates the role of a brain neurochemical called dopamine in working memory and frontal lobe function. Levels of this neurochemical have been shown to decline with normal aging. The lab performs pharmacological studies during which direct dopaminergic medications are administered to normal human subjects, as well as patients with frontal lobe lesions, to determine the effect of dopamine on cognition. We have also begun to study another neurochemical, acetylcholine, which has been linked to long-term memory and is severely depleted in Alzheimer's disease patients. Finally, behavioral studies are also performed in patients with frontal lobe dysfunction (e.g. stroke, head injury, Parkinson's disease) in order to further understand the mechanisms that underlie working memory and to serve as a comparison to studies of the normal aging process.