Table 1.

Movement and anxiety behavior in S6K knockout mice

S6K1 knockout mice have abnormal hypoactive exploratory behavior. Open Field Behavior: Mice were placed into the center of a brightly lit box and motor movement was automatically tracked over a period of 30 min. S6K1 knockout (KO) mice displayed deficits in all measures of movement. In contrast, S6K2 KO mice were comparable with wild-type mice in the same measures of movement. Because mice tend to avoid the center of the open field, the percentage of time moving in the center compared with the periphery is used as a measure of anxiety. S6K1 KO and S6K2 KO animals spent a comparable proportion of time in the center of the box as wild type, indicating that this behavior is normal in both the S6K1 and S6K2 KO mice. It should be noted that strain-specific differences were apparent among the wild-type mice from each strain. Rotating Rod Performance: Mice were placed onto a rotating rod that started at 4 rpm and incrementally accelerated each 20 sec to a final 40 rpm and the latency to fall was recorded. Eight trials were performed over a span of two days (4 trials/day with an intertrial interval of 1 h). S6K1 KO and S6K2 KO mice performed normally on the rotating rod task during both the initial trial and final trial. Learning curves were indistinguishable between S6K1 KO, S6K2 KO, and respective wild-type littermates (data not shown). Consistent with previous reports, S6K1 KO mice have decreased body weight (86 ± 5% of wild type, P < 0.05), whereas S6K2 KO mice maintain normal body weight (102 ± 4% of wild type, P > 0.05) (Shima et al. 1998; Pende et al. 2004). However, this impairment in size did not affect performance in the rotating rod task.

^aHorizontal and vertical activity are system-defined variables in Versamat software.

^bP < 0.001 with a Student’s t-test.

^cP < 0.05 with a Student’s t-test.