Dennis J. Selkoe is a prominent researcher in the field of Neurologic Diseases, focusing on the biochemistry and molecular cell biology of neuronal degeneration and aging in the mammalian brain. His work primarily addresses Alzheimer's Disease (AD) and Parkinson's Disease (PD). Dr. Selkoe's laboratory was a pioneer in developing methods for the purification and analysis of intraneuronal paired helical filaments and extracellular amyloid fibrils, which are critical hallmarks of AD neuropathology. He has conducted extensive studies on the trafficking and processing of β-amyloid precursor protein (APP), a type 1 integral membrane glycoprotein essential to AD. His laboratory has made significant discoveries about the normal and toxic properties of Aβ produced from APP and the mechanisms involved in Aβ production. Furthermore, his research has explored the roles of γ-secretase in APP and Notch signaling, as well as the functions of gene products related to PD, particularly alpha-synuclein. To realize these studies, a variety of methods, including cell culture, protein biochemistry, molecular biology, immunohistochemistry, light and electron microscopy, and electrophysiology, are utilized alongside animal modeling.