This is a proposal to validate two noninvasive functional mapping techniques, functional MRI and human cerebral evoked potentials, which have both been used to map the location of human sensory cortex. The cortical hand and foot sensory areas will be mapped and registered in 3-D rendered images of the cortex. The resulting images will contain information regarding cortical structure and function: 1) maps of local changes in blood metabolism in response to tactile stimulation, and 2) sensory evoked potential dipoles derived from peripheral nerve stimulation. The validity of these totally noninvasive maps will be assessed by direct cortical mapping studies of 25 neurosurgery patients. If these two procedures can be validated from intraoperative mapping studies, it will allow them to be utilized as noninvasive empirical tests for many areas of brain research. This research proposal is based on a collaborative arrangement between a group of medical researchers at the University of Chicago and a dipole modeling group at Abratech, Inc. The validation of these two noninvasive techniques is important so that studies of the brain's functional organization are based on sound scientific principles. These potentially useful techniques need to be validated before they are trusted to clinical use. If they can be validated, the two techniques could routinely provide surgeons with noninvasively obtained maps of critical cortical areas before surgery, to aid in surgical planning. Their validation would also improve confidence in using these mapping techniques in other areas of scientific research.
