Ann Graybiel studies the basal ganglia, forebrain structures that are profoundly important for normal brain function but are also implicated in Parkinson's disease, Huntington's disease, obsessive-compulsive disorder, and addiction. Graybiel's work is uncovering neural deficits related to these disorders, as well as the role the basal ganglia play in guiding normal behavior.
The basal ganglia are best known for their control of movement. Parkinson's disease, for example, results from the degeneration of neurons that release the neurotransmitter dopamine within the striatum, the largest part of the basal ganglia. It is becoming clear, however, that the basal ganglia do more than just control movement. These structures have been implicated in psychiatric diseases and addiction, and damage to the basal ganglia can affect not only movement but also mood and cognition. Graybiel believes that this broad range of functions reflects the capacity of the basal ganglia to influence how we select actions–motor actions as well as actions of thought.
Habits of thought and emotion
Graybiel believes that the core function of the basal ganglia is the type of learning that leads to the formation of habits. Habits are sequences of behavior that are learned to the point where they become automatic. Many everyday motor actions become habitual through repetition, but we also develop habits of thought and emotion. If cognitive and emotional habits are also controlled by the basal ganglia, this may explain why damage to these structures can lead not only to movement disorders like Parkinsons's disease, but also to repetitive and intrusive thoughts, emotions, and desires.
Graybiel's team uses electrical recordings, behavioral tests, and gene-based approaches to study these issues. They recently demonstrated dramatic changes in neural activity in the striatum as animals learned new habits. They also found that these changes are coordinated with activity patterns in the hippocampus, a brain structure involved in memory of facts and events. Graybiel is currently focusing on new methods for influencing the activity of the striatum, and on novel genes that her group has discovered in this brain region. These genes appear to be critical for the brain's response to drugs of abuse and to L-dopa, a major therapeutic drug for Parkinson's disease. Graybiel is exploring the potential of these genese for therapeutic drug development.
Ann Graybiel '71 joined the MIT faculty in 1973 and in 1994 was named Walter A. Rosenblith Professor of Neuroscience in the Department of Brain and Cognitive Sciences. In 2001, she was appointed Investigator at the McGovern Institute and was named a recipient of the National Medal of Science, the nation's highest science and technology honor. In 2002, Graybiel was awarded the James R. Killian Faculty Achievement Award which recognizes extraordinary professional accomplishment by full-time members of the MIT faculty. In 2004, she received the Woman Leader of Parkinson’s Science award from the Parkinson’s Disease Foundation, and in 2006, she was named the Harold S. Diamond Professor by the National Parkinson Foundation in recognition of her contributions to the understanding and treatment of Parkinson’s Disease. In 2008, she was named Institute Professor, the highest academic award at MIT, and in 2012 she shared the Kavli Prize in Neuroscience. Ann is a member of the National Academy of Sciences, the Institute of Medicine, and the American Academy of Arts and Sciences.
Image: Kent Dayton