Returning to UCSF for a Behavioral Neurology fellowship, Dr. Seeley developed expertise in the differential diagnosis and treatment of patients with neurodegenerative disease. Struck by the focality of these illnesses, he began to question how events at the molecular level could target small subsets of the brain's roughly 86 billion neurons. This biological problem, referred to as selective vulnerability, has become the primary focus of Dr. Seeley’s research. He addresses this question through behavioral, functional imaging and neuropathological studies. The goal of his research is to determine what makes brain tissues susceptible or resistant to disease, with an eye toward translating these findings into novel treatment approaches.