All surgery experiments were performed in accordance with the University of Washington regulations on aseptic animal surgery, and all efforts were made to minimize suffering. For all surgical procedures, mice were anesthetized with a mixture of ketamine (130 mg/kg, Zoetis Inc., Kalamazoo, MI) and xylazine (8.8 mg/kg, Akorn Inc., Lake Forest, IL). Animal body temperature was maintained using a heating pad placed underneath the animal. Local anesthetic (2% lidocaine, Hospira Inc., San Clemente, CA) was applied to all incisions.
For viral injections and probe insertion, a small hole was drilled in the skull directly above the dorsal hippocampal CA1 region. The following stereotaxic coordinates relative to Bregma were used: A-P: 1.95 mm × a (a = lambda-bregma distance/4.2), M-L: 1.35 mm. A cannula (Mauna Kea Technologies, Paris, France) was attached to the skull with dental acrylic (Lang Dental Manufacturing Co. Inc., Wheeling, IL) and small set screws. One week after the surgery, 0.5 μl AAV1-GCaMP6m virus was injected through the cannula into the CA1 (D-V: 1.55 mm). Mice recovered and expressed GCaMP6m for eight weeks prior to the behavior experimentation and imaging. Mice were single-housed after surgery.
For viral injections and probe insertion, a small hole was drilled in the skull directly above the dorsal hippocampal CA1 region. The following stereotaxic coordinates relative to Bregma were used: A-P: 1.95 mm × a (a = lambda-bregma distance/4.2), M-L: 1.35 mm. A cannula (Mauna Kea Technologies, Paris, France) was attached to the skull with dental acrylic (Lang Dental Manufacturing Co. Inc., Wheeling, IL) and small set screws. One week after the surgery, 0.5 μl AAV1-GCaMP6m virus was injected through the cannula into the CA1 (D-V: 1.55 mm). Mice recovered and expressed GCaMP6m for eight weeks prior to the behavior experimentation and imaging. Mice were single-housed after surgery.