Impaired memory in the mib1 cKO mice. (A) Total path distance during the open field test. (B) Percentages of path distance in the peripheral region and in the central region during the open field test. (C, D) Rotarod test for motor learning. (C) Shows the average time spent on the rod in the fixed-speed test. (D) Shows the average time spent on the rod in the accelerating-speed test. (E) The amplitudes of the acoustic startle response for different intensities of acoustic stimuli are presented. (F) Mib1 cKO mice have impaired object recognition test. (G) Tone-dependent freezing behavior of wild-type and mib1 cKO mice at 24 h after training. The rate of freezing response was quantified before (pre-CS) and after conditioned stimuli (CS). (H) Freezing behavior during contextual fear conditioning test at 24 h after training. (I) Mib1 cKO mice showed impaired spatial memory in Morris water maze test. Mice were tested on their ability to navigate a hidden platform three times per day for 8 days. A 90-s probe trial was performed without the platform 2 h after the daily training on day 8, and staying time in each quadrant (T, target quadrant; L, left quadrant; O opposite quadrant; R, right quadrant) was recorded. Spatial histograms of the animals’ location during probe trials are illustrated. (J) Escape latency was normal in Mib1 cKO mice during four repetitive trials in the visible platform test in Morris water maze test. Error bars show standard error of the mean. *Significant difference; p < 0.001.