2.6 Balance ability test
​The balance beam is suspended at one end and fixed at the other, with a soft cushion placed below it to prevent injuries from falling. The rats were placed at the mark of the wooden strip, stood and started timing, and the 2 min on the balance beam was recorded with a camera. Calculated in 6 points, 0 points: smooth over the balance beam; 1 point: can grasp the edge and not fall. 2 points: grasp the wood, one foot off. 3 points: hold on to the wooden bar, drop or flip both feet off the balance beam (>2 min). 4 points: try to maintain a stable, and eventually fall (>90 sec). 5 points: try to keep steady and eventually fall (>60 sec). 6 points: not maintain a stable, directly drop (<30 sec).