Additional Study Information: The purpose of this study is to carefully examine how dementia can affect mood and behavior. In this study, we will use Magnetic Resonance Imaging (MRI) to better understand the relationship between thinking, mood, behavior and the brain. We are currently seeking participants who have a diagnosis of dementia, such as Alzheimer's Disease, who are between 40-90 years old, and who speak English or Spanish. Participation involves coming in with a study partner (someone who knows you well) for a single visit for a total of 4-5 hours. Participants will answer questions about their recent mood and emotions and complete an MRI scan. Participants will be compensated $50-$100.