A central issue of brain development is how the intricate patterns of nerve connections are formed by incoming sensory nerve cell processes, called afferent axons, on central target nerve cells. In rodents, the afferents for touch from the facial whiskers form a pattern of discrete units at every level in their pathway from the face to the sensory cortex of the forebrain. In the cortex, the central terminal patterns of these aligned axons form structures called barrels, from their shape. This project will analyze how the cells called glial, which surround nerve cells in the brain, may assist in forming the pattern of the axons into these barrels. Anatomical and biochemical techniques, including antibody binding, will be used to assess the developing patterns under a variety of conditions. Experiments will compare glial antigens with cell-adhesion molecules, will correlate distribution of afferents between normal and abnormal development using mutant mouse strains, and use lesion studies to establish how boundaries change and/or reform during subsequent regeneration. This work pursues a novel and potentially important issue for developmental neuroscience, and results will have an impact on developmental biology as well.
