Stereotactic AAV Injection in Mice

We performed AAVs injection as previously described^{52 (link),53 (link)}. In brief, mice 6–8 weeks of age were stereotaxically injected. Animals were anesthetized with isoflurane (1–2%) and placed in a stereotaxic frame. The adeno-associated virus AAVDJ-CaMKII-iCre-T2A-mCherry (3.55~7.87 ×10¹¹ vg/mL) or AAVDJ-CAMKII-mCherry (7.83 × 10¹² vg/mL) were injected to the olfactory bulb or the PC bilaterally. For AAV transduction to the granule cell layer of the olfactory bulb, we injected 300 nL of AAV to each olfactory bulb bilaterally. For AAV transduction to the PC, we injected AAV to three coordinates to either side of the brain, with a total of six injection coordinates bilaterally with 300 nL injection volume per injection coordinate. For injection, we used a pulled glass capillary (Drummond) and injected through nanoliter pressure injection (Nanoject3, Drummond). Stereotactic injection coordinates to target the olfactory bulb or PC were obtained from the Paxinos and Franklin atlas (for olfactory bulb AP:4.2 mm ML:1.0 mm DV:1.0 mm from brain surface; for PC AP:1.8, 0.5, −0.5 mm ML:2.7, 3.5, 3.9 mm, DV:3.8, 3.8, 4.2 mm from brain surface). Animals were allowed to recover for at least 4 weeks before being used in experiments.