Age but not sex affects motor recovery after unilateral sensorimotor cortex suction-ablation in the rat

Both age and sex can influence recovery after brain injury. To determine the impact of these variables on motor recovery, young (2 month old) and older (5-6 months old) male and female rats were first trained to traverse a narrow elevated beam. Rats then underwent suction-ablation of right sensorimotor cortex or sham operation. Motor recovery was measured by repeated testing on the beam over 3 weeks. Shamoperated rats performed perfectly regardless of age or sex throughout testing. There was no difference in beam-walking scores among the groups of lesioned rats on the first trial 24 hrs. after injury (Kruskal-Wallis H = 0.18, p = 0.98). There was a significant effect of age (two-way ANOVA F1,32 = 29.58, p < 0.0001) but not sex (ANOVA F1,32 = 0.78, p = 0.38) on subsequent recovery. These data show that motor recovery after unilateral injury to the sensorimotor cortex varies with age, but not sex.