2.4.2. Spontaneous Activity

Each mouse was left to explore an acrylic test chamber (40.5 cm × 40.5 cm × 30.5 cm) under dim light and with background noise (80 dB) for 16 min. Their activity was recorded using a Digiscan apparatus (Omnitech Electronics Inc., Columbus, OH, USA, model RXYZCM-16). Their horizontal, vertical, and spatial movements were detected by the photocells and processed by a software program.

### 2.4.3. Coordinated Running

A motor-driven cylinder rotating at increasing speed was used to measure motor learning and running performance (Rotorod, Omnitech Electronics Inc., Columbus, OH, USA, Model # AIO411RRT525M). The mice were given two training sessions per day (four trials/session with a 10 min inter-trial intervals (ITI)), which continued until improvements failed over three consecutive sessions. The average of latency to fall for the four trials in each session was used for motor learning and for the final session when stable performance was achieved.

#### 2.4.4. Reflexive Musculoskeletal Responses

Walk initiation: record the latency to move one body length immediately after being placed on a smooth surface. Alley turn: record the latency to make a full turn in a dead-end alley. Negative geotaxis: record the latency to turn 180 ◦ in either direction when placed facing downward on a 45 ◦ tilted grid. Wire suspension: record the latency to grasp wire with hindpaws after being suspended from wire by front paws and the latency to fall (two trials/session). The mice received four sessions (one/day) and latencies were averaged across the four sessions. A maximum of 60 s for each test was used.
