Molecular Cellular and Developmental Neuroscience (MDCN) is not a study section, it is an integrated review group (IRG), a cluster of individual review panels. Applications go through two stages of referral during peer review. First, the Center for Scientific Review’s (CSR’s)  Division of Receipt and Referral assigns the applications to an IRG. The IRG staff then assign the applications to particular panels within the IRG. Check in the Commons 4 to 6 weeks after submitting your application; it should have been assigned to a particular panel and a Scientific Review Officer.
If your review assignment is an odd string of initials (like MDCN) and no scientific review officer is named, go to the CSR home page and insert the initials in the upper search window (“Search Integrated Review Group (IRG)/Study Group using keywords”). The IRG will be returned, and you can click on that link to find the study sections clustered within it.