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 which receive those signals. Correct central connectivity has been suggested to depend on having 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 with the addition of clear anatomical organization. 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 find out how deprivation- induced changes in activity of a particular neurotransmitter molecule (GABA) may provide a mechanism for changing the relative levels of inhibition versus excitation during development and establishment of normal connections. Results from this novel model system will have an important impact on sensory neuroscience as well as developmental neuroscience.
