Figure 4.

Rotarod performance, locomotion, and gait analysis in dMHb^CKO mice. A, Accelerating rotarod latency to fall times for dMHb^CKO mice over four trials on day 1 of testing compared with control mice, showing a significant relative deficit for dMHb^CKO mice in this test. *p = 0.02, significant difference between genotypes for those trials. **p = 0.0013, significant difference between genotypes for those trials. ****p < 0.0001, significant difference between genotypes for those trials. B, Average latency to fall time in the rotarod for day 1 of testing (the lowest of the four values for each mouse was discarded before averaging). ****p < 0.0001. C, Correlation between latency to fall in the rotarod for four trials on day 1 versus day 2 of testing. Performance on day 1 is predicative of that on day 2. r = 0.66, p = 0.0003. D, Total distance traveled in the open field. No difference was observed for control and dMHb^CKO mice during the 30 min testing period. E, Distance traveled in the home cage (PhenoTyper; Noldus Information Technology) tracked over a 24 h day, following 2 d of acclimatization. Both genotypes were more active during the night, as expected, and no differences were observed between genotypes. White and black bars below represent time of lights-on and darkness, respectively. The same cohort of mice was used for experiments in A–E (n = 11 control and n = 14 dMHb^CKO mice). F, G, Balance beam test. The test consisted of five trials on each of four successively smaller round beams, which were video recorded for analysis. The last three completed trials for each beam diameter were used to compute the average transit time (F), and the average number of faults in which a rear paw lost contact with the beam (G) for each subject. Overall, the dMHb^CKO mice took longer to traverse the bars and committed more faults. N = 9 control and N = 10 dMHb^CKO mice.