Shortly after Marcus Raichle, M.D., joined Washington University, in 1971, he worked with the research team that created the first positron emission tomography (PET) scanner, designed with old machine parts and borrowed equipment.
Today, Raichle is recognized as a pioneer in mapping the functions of the human brain in health and disease, first with PET and later with magnetic resonance imaging (MRI). He is regarded as one of neurology’s top minds.
Raichle is a professor of radiology, neurology and neurobiology in the School of Medicine; professor of psychology in Arts & Sciences; and professor of biomedical engineering in the School of Engineering & Applied Science. Over the years, he has led a team of researchers who have made significant contributions to the understanding of human brain function through the development and use of PET and of functional MRI (fMRI). A specialized form of brain imaging, fMRI records changes in brain activity as the result of changes in local brain oxygenation. The researchers have mapped areas in the brain critical for language, attention, emotion, memory and learning. More recently, they have analyzed the metabolism of the brain and its role in diseases such as Alzheimer’s and Parkinson’s.
Raichle’s landmark paper, published in 1988, which introduced how language is organized in the normal human brain, was a major catalyst for a new scientific discipline. Known as cognitive neuroscience, the field examines the relationship between human behavior and brain function. Critical support from the James S. McDonnell Foundation and the Pew Charitable Trusts followed and, as a result, there is today a worldwide effort to understand the brain in all facets of human endeavor.
In other studies, Raichle and his team examined brain activity in subjects resting quietly but awake, as opposed to conducting goal-oriented tasks. Their research revealed a high degree of organized brain activity present in this resting state.
They discovered, unexpectedly, a network in the brain, which they dubbed the default mode network. Critical to the brain’s organization, this network is the system most directly affected by Alzheimer’s. The team has intensified its focus on this relationship as a means to better understand and treat the disease.
“Our discovery of the remarkable features of the resting state marked a paradigm shift in brain studies,” Raichle says, “and has opened new doors of research on the human brain in health and disease.”