Technologies for the 21st Century Human Brain Mapping

	MEG Dynamic brain visualization Functional Magnetic Resonance Imaging Memory task Primary visual cortex activity
MEG	Magnetoencephalography (MEG) is the study of brain function using sensitive detection systems to measure the magnetic fields emanating from the head as a result of brain activity. In the image to the right, a magnetic field resulting from the brain's response to a visual stimulus is shown as a color contour map on a head surface reconstructed from MRI data. The disks represent sensor locations in a full-head MEG system.
Dynamic brain visualization	Researchers at the University of California-San Diego's (UCSD) Cognitive Sciences Department are using MEG to investigate the flow of information in the brain and how it relates to mental functions and cognition. Visualization in 3-D enables one to "see" the dynamic characteristics of brain processes and the interplay of different functional areas involved and may lead to a new understanding of how the brain works. This image shows the electric current distribution in the visual, motor, and Broca's and Wernicke's areas involved in language processing. Bright red areas are the sites of present activity. The surrounding orange areas show the variability of activity over time. To produce an image of activity in these four primary areas that are normally not active at the same time, researchers simulate excitations of the neuronal cell groups using UCSD's neuromagnetic simulation package.
Functional Magnetic Resonance Imaging	Functional MRI experiments have been used to investigate all aspects of brain function, including a concept known in cognitive psychology as working memory. Each subject's brain is scanned while he or she performs a working memory task (see below) and a control task. Results to date support the theory that the prefrontal cortex becomes engaged when recently presented information must be represented and actively maintained to perform a task. This type of study leads to improved understanding of memory function, which impacts clinical treatment of major diseases such as schizophrenia and amnesias.   The primary visual cortex becomes active when a striking pattern is shown to the subject, visualized in the image at the bottom of this page. Both images were displayed in near real-time while the subject was being scanned. NIH-supported researchers at Carnegie Mellon University used Pittsburgh Supercomputing center's Cray T3E to process the data acquired by the MRI scanner at the University of Pittsburgh Medical center and visualized the results on a Silicon Graphics Onyx Reality Engine.   The processing included image reconstruction and motion correction to compensate for the movement of the subject's head. This real-time capability will make it possible to use brain-mapping as a routine clinical tool in diagnosing and treating brain pathology, as in neurosurgical planning for tumor removal. For example, neurosurgeons who use standard MRI to locate tumors will now be able to determine which cognitive and sensory-motor abilities (for example, language and motor-skills) are located close to the tumor site, allowing them to further refine their surgical plans.
Memory task	Brain activity during the memory task.
Primary visual cortex activity	Brain activity that occurs when a pattern is shown to the subject of the experiment. The primaty visual cortex becomes active.