title: Behind the scenes of functional brain imaging: a historical and physiological perspective.
abstract: At the forefront of cognitive neuroscience research in normal humans are the new techniques of functional brain imaging: positron emission tomography and magnetic resonance imaging. The signal used by positron emission tomography is based on the fact that changes in the cellular activity of the brain of normal, awake humans and laboratory animals are accompanied almost invariably by changes in local blood flow. This robust, empirical relationship has fascinated scientists for well over a hundred years. Because the changes in blood flow are accompanied by lesser changes in oxygen consumption, local changes in brain oxygen content occur at the sites of activation and provide the basis for the signal used by magnetic resonance imaging. The biological basis for these signals is now an area of intense research stimulated by the interest in these tools for cognitive neuroscience research.
authors.affiliation: Washington University School of Medicine, 4525 Scott Avenue, St. Louis, MO 63110, USA.
authors.forename: M E
authors.initials: ME
authors.lastname: Raichle
mesh_terms: D000818:Animals; D001921:Brain / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000502:physiology*; D001931:Brain Mapping; D002560:Cerebrovascular Circulation / Q000502:physiology; D003952:Diagnostic Imaging; D049673:History, 20th Century; D006801:Humans; D008279:Magnetic Resonance Imaging; D009488:Neurosciences / Q000266:history; D014055:Tomography, Emission-Computed