Fig. 4

Results of the light–dark (LD) test. a Frequency of transition in the LD test. The number of transitions in the T2DM group was significantly larger than that in the non-diabetic group. However, the number of transitions significantly decreased after surgery in the T2DM mice. b Time spent in the light box. There was no difference between the non-diabetic group and the T2DM group during the perioperative period. Each graph is shown as medians ± quartile, n = 15 per group. *P < 0.05, **P < 0.01