Scientific), insulin (1 mg/L) (Sigma-Aldrich), 0.5 ascorbic acid and 5% horse serum (Thermo Fisher Scientific) (pH 7.2). Slices were maintained in an incubator at 34 °C/5% CO2, and were fed 3 times per week by replacing half of the growth medium with fresh medium. Slices were infected with purified AAV viruses in a 1:50 dilution with 5% glycerol/10% sucrose PBS solution, using a Nanoject III injector (Drummond Scientific Company; Broomall, PA) one day after plating. Recordings were made 6–7 d post-infection.
