Fig. 1

DI supplementation improved cognitive decline in mice on HF diet. The object location test was performed to evaluate the spatial memory of mice (a–c). a Percentage of time spent with the object in the novel place to total object exploration time. b The total object exploration time. c Representative track plots of LC+Veh, LC+DI, HF+Veh, and HF+DI groups recorded by the SMART video tracking system in the testing phase. Note that the LC+Veh mouse spent more time exploring the object in the novel place whereas the HF+Veh mouse did not show preference to the object in a novel place. The novel object recognition test was performed to evaluate the object recognition memory of mice (d–f). d Percentage of time spent with the novel object to total object exploration time. e The total object exploration time. f Representative track plots of LC+Veh, LC+DI, HF+Veh, and HF+DI groups recorded by the SMART video tracking system in the testing phase. The nest building test was used to assess the activities of daily living of mice (g–i). g The nest score and h untorn nestlet weight (amount of untorn nesting material). i Representative nest result of LC+Veh, LC+DI, HF+Veh, and HF+DI groups. n = 12 mice for each group in behavior tests. Values are mean ± SEM. ^*P < 0.05, ^**P < 0.01, ^***P < 0.001