Project Summary The goal of this exploratory proposal is to deliver and express genetic material in the ferret model system early in development. Our strategy is based on an existing method developed in mouse for the rapid and spatially localized expression of DNA plasmids in postmitotic cells, a technique termed ‘iontoporation’. We aim to express CRISPR/Cas9 into ferret primary visual cortex (V1) to manipulate the expression of specific genes critical for the development and function of visual circuitry. Ferret is an ideal model system, as they are born relatively immature and visual circuit development is well-characterized. In this application, we propose to optimize and validate iontoporation in ferret to knockdown the expression of N-Methyl-D-aspartic acid receptors (NMDARs) to elucidate their functional role in the formation and function of V1 circuitry. We will validate the technique in vitro and in vivo, and start obtaining preliminary data for a collaborative R01, on the role of NMDARs in the development and function of local and long-range (between columns) horizontal connections in layers 2-3 of ferret V1. Successful development of this approach will open the door to genetic manipulation in a higher mammal with cortical columnar organization of the neocortex similar to primates and humans. It will also allow the development of genetic models of brain pathologies such as Schizophrenia.