MAPPING HUMAN BRAIN ACTIVITY IN-VIVO

A wide range of structural and functional techniques now exists to map the human brain in health and disease. These approaches span the gamu t from external tomographic imaging devices (positron-emission tomogra phy, single photon-emission computed tomography, magnetic resonance im aging, computed tomography), to surface detectors (electroencephalogra phy, magnetoencephalography, transcranial magnetic stimulation), to me asurements made directly on the brain's surface or beneath it (intrins ic signal imaging, electrocorticography). The noninvasive methods have been combined to provide unique and previously unavailable insights i nto the macroscopic organization of the functional neuroanatomy of hum an vision, sensation, hearing, movement, language, learning, and memor y. All methods have been applied to patients with neurologic, neurosur gical, and psychiatric disease and have provided a rapidly expanding k nowledge of the pathophysiology of diseases such as epilepsy, cerebrov ascular disease, neoplasms, neurodegenerative diseases, mental illness , and addiction states. In addition, these new methods have become a m ainstay of preoperative surgical planning and the monitoring of pharma cologic or surgical (transplantation) interventions. Most recently, th e ability to observe the reorganization of the human nervous system af ter acute injury, such as occurs with cerebral infarction or head trau ma, or in the course of a progressive degenerative process such as Alz heimer's or Parkinson's disease, may provide new insights and methods in the rapidly expanding field of neurorehabilitation. Our newfound ab ility to generate maps and databases of human brain development, matur ation; skill acquisition, aging, and disease states is both an excitin g and formidable task.