Purpose. This funding opportunity announcement (FOA) encourages Exploratory/Developmental (R21) grant applications from applicant organizations directed toward the discovery and preclinical testing of novel compounds for the prevention and treatment of nervous system disorders. Mechanism of Support. This FOA will use the NIH Exploratory/Developmental (R21) award mechanism and runs in parallel with a FOA of identical scientific scope, PAR-10-001 that encourages applications under the Research Project Grant (R01) award mechanism. Funds Available and Anticipated Number of Awards. Awards issued under this FOA are contingent upon the availability of funds and the submission of a sufficient number of meritorious applications.