930403 Steindler The cerebral cortex provides the neural substrate for thinking, perception, and memory. It is divided into a mosaic of regions with different cellular composition and connections. Each region is specified to process a particular type of information. Some regions process information from sensory receptors, others process information coming from brain centers that program responses. How this differentiated mosaic develops from an undifferentiated equipotential embryonic matrix is a subject on intense interest and controversy. This NSF Small Grant for Exploratory Research will enable Dr. Steindler to explore the role of an extracellular matrix molecule called tenascin in the formation of cortical boundaries. Tenascin is secreted by neuroglia, the non-neuronal support cells of the nervous system. It is found at the boundaries of cortical regions early in development but disappears by maturity. Dr. Steindler hypothesizes that this molecule forms a barrier between adjacent regions and prevents mixing of fiber afferents. He will use newly developed antibodies to tenascin to study the role of this molecule in the formation of regional boundaries in the "whisker-barrel field," an area of cortex with regionally distinct boundaries that are easily discerned. Since tenascin has a widespread distribution in the animal kingdom, this work should provide insight into general mechanisms of pattern formation during development. More specifically the results will have implications for theories of cortical development and cortical regeneration after injury in the adult. ***
