Newborn mouse pups (C57BL6/J, males and females) were isolated from the home cage at postnatal day 3, kept on a heating pad and anesthetized with intraperitoneal injection of a cocktail containing 0.67 mg/ml medetomidine (Dorbene; Dr. Graeub AG) and 1.7 mg/ml midazolam (Dormicum; Roche) in a total volume of 3.7 μl. The pups were placed on a plastic form mounted on a stereotactic frame and which was especially designed to maintain their head in a fixed position. Simultaneous bilateral intracerebroventricular (ICV) injections were performed using 30 G sharp needles connected to a KDS310 nanopump (KD Scientific). A total dose of 1E + 7 TU of AAV2/6 vector suspension, in a maximal volume of 1.5 µl, was injected in each lateral ventricle at a speed of 1.5 μl/min. Mice receiving virus were randomized during injection day in order to have all groups represented in a given litter. Animals were returned to their home cage after anesthesia reversal with a subcutaneous injection of 5 μl of 1 mg/ml atipamezol (Alzane; Dr. Graeub AG).