FIGURE 5.

The stimulated motor cortex mediates motor recovery after injury. Rats were trained to cross a horizontal ladder with irregularly spaced rungs until they achieved a baseline error rate below 20%. (A) Effect of motor cortex stimulation beginning the day after injury. The error rates increased in the affected forelimb to a similar degree in rats with injury only (blue) and rats with injury and stimulation (red). Modified from Carmel et al. (2010). (B) Effect of motor cortex stimulation after chronic injury. Until the start of stimulation (weeks 1–7) the error rates in the two groups were not different. After the start of stimulation (weeks 8–11) the groups differed significantly (repeated measures ANOVA, with Bonferroni post hoc correction, asterisk, p = 0.03). (C) After stimulation, motor cortex inactivation reinstates the motor impairment. After completion of motor cortex stimulation, performance on the horizontal ladder was measured before and during inactivation. In the rats with injury only, inactivation did not change the error rate in the impaired forelimb (blue bars are not different). In contrast, in rats with injury and stimulation (red bars) inactivation of the stimulated motor cortex reinstated their initial deficit in the ipsilateral forelimb (paired t-test, p = 0.01). (B,C) were modified from Carmel et al. (2014).