PI: Land IBN 9603964 A central question in development of the brain is how precise sets of functional connections are made between particular groups of nerve cells. Model systems to study this question often involve a well-defined sensory organ and the target areas in the cortex of the brain that receive the sensory signals. The development of correct central connections and of normal sensitivity by central neurons both often depend on normal sensory experience during development; with deprivation, there often are physiological and biochemical changes in the target neurons in sensory cortex. This study uses the tactile whiskers of rodents and their characteristic "barrel fields" of target nerve cells in the cortex as a model, because the system has a clear anatomical organization that facilitates comparisons between the normal and deprived conditions. The whiskers are easily trimmed at different times to provide a painless and easily reversible form of sensory deprivation in a local area. Physiological, biochemical and anatomical techniques will be used to investigate the effects of deprivation on a particular type of excitatory nerve terminals in developing barrel fields. Results from this model system will be relevant to understanding how specific sets of connections between chemically defined neurons are established during development, and how activity levels in these neurons affect their development. The results will have an important impact on sensory neuroscience as well as developmental neuroscience.
