Effect of genotype and age on rotarod performance.

<p>Data are expressed as the mean ± SEM of measures from the following number of mice of each age and genotype: young (wt = 34, ko = 35), middle-aged (wt = 23, ko = 46) and old (wt = 25, ko = 29) male mice. Asterisks above bars indicate significant difference between age-matched wt and ko groups. Asterisks above lines indicate significant difference between indicated means. *<i>P</i><0.05; **<i>P</i><0.01; ***<i>P</i><0.001.