David C. Van Essen, Ph.D., the Edison Professor of Neurobiology and head of the Department of Anatomy and Neurobiology, will outline his team's work at a presentation session from 10:30 a.m. to 1:30 p.m. ET on Monday, Feb. 17 at the annual meeting of the American Association for the Advancement of Science in Denver, Colo.
"It is vital to have improved methods for analyzing and visualizing the torrent of information that is becoming available from neurobiologists so that we can better understand the brain in health and disease," says Van Essen. "Just as maps of the Earth locate continents, mountain ranges and nations, our cortical maps show the locations of the brain's structural and functional subdivisions. They are the most accurate and comprehensive maps available for humans, macaque monkeys and mice."
The maps outline both structural and functional areas in the cerebral cortex and the cerebellar cortex, which form the convoluted surfaces of the brain. The cerebral cortex is believed to be the seat of thought, learning, emotion, perception, sensation and movement. The cerebellar cortex is implicated in the coordination of incoming information and in controlling movement.
Both areas are highly folded and compact structures. Van Essen has taken advantage of their sheet-like nature to produce computerized maps of the cortical surfaces analogous to maps of the earth's surface.
Many imaging techniques can map individual slices of the brain. In their cartography work, Van Essen's team has 'stacked' those slices in a 3-dimensional 'Dagwood sandwich' displaying functions performed at various levels of the cortex. They are developing several kinds of brain atlases simultaneously: The top level registers brain volume; the middle level measures the brain's surface area; the bottom level "flattens" the cortex to correlate brain structure with function.
The maps are repositories for information generated by neuroscientists around the world. Such maps are essential, Van Essen says, because a growing number of technical advances have greatly accelerated the pace at which neuroscientists acquire experimental data about the brain. Detailed maps such as these will help physicians better understand the implications of brain damage due to stroke, epilepsy, trauma and other causes, and will help guide neurosurgeons in the operating room.
Nonetheless, science still has a long way to go. "Our present level of understanding cortical organization and function remains fragmentary," Van Essen says. "It's similar to the rudimentary understanding held by 17th-century cartographers of the earth's geographic and political subdivisions."
The cortical maps being assembled by Van Essen and his colleagues will be freely available and electronically accessible to the scientific and educational community. Just as in the past decade databases for genomics and proteomics have become essential tools in molecular and cellular biology, he believes web-based sources of neuroanatomical, neurophysiological and neuroimaging data will become powerful and pervasive tools for basic and clinical neuroscience in the coming decade.
Van Essen, DC. Cortical Cartography: Mapping Cortical Structure and Function in Human, Monkey and Mouse. American Association for the Advancement of Science, Feb. 17, 2003.