A default mode of brain function : history of an evolving idea [electronic resource] / Marcus E. Raichle.

(CIT): The concept of a default mode of brain function arose out of a focused need to explain the appearance of activity decreases in functional neuroimaging data when the control state was passive visual fixation or eyes closed resting. The problem was particularly compelling because these activity decreases were remarkably consistent across a wide variety of task conditions. Using PET, we determined that these activity decreases did not arise from activations in the resting state. Hence, their presence implied the existence of a default mode. While the unique constellation of brain areas provoking this analysis has come to be known as the default system, all areas of the brain have a high level of organized default functional activity. Most critically, this work has called attention to the importance of intrinsic functional activity in assessing brain behavior relationships. Marcus E. Raichle is known for his pioneering research in the development and use of an imaging technique called positron emission tomography (PET) to map specific brain areas used in tasks such as seeing, hearing, reading and remembering as well as emotion. Raichle was a member of the team that developed PET at Washington University during the 1970's. The technique, equivalent to tissue autoradiography but done safely in vivo, allows researchers to safely and non-invasively study the living human brain and track and record its function in health and disease. By using PET to monitor blood flow and metabolism in the human brain, Raichle and his collaborators were able to show how the brain responds when a subject is asked to perform tasks as diverse as memorizing words or anticipating an unpleasant experience.

Channel: NIH Video Length: 61m 44s Date Found: Tue, Sep 16 2008 6:47 PM Category: Science Date Produced: View Count: 20