Using a rat brain matrix, slices of approximately 1 mm were taken from each brain, and the slices that contained the PFC, HIP, and dorsal STR were identified according to a rat brain atlas [35]. Tissues from specific regions of interest were collected bilaterally from each brain using a 3.00-mm Harris Micro-Punch (GE Healthcare Life Sciences, Piscataway, NJ, USA) and stored at −80°C until use.