Training Intensity Affects Motor Rehabilitation Efficacy Following Unilateral Ischemic Insult of the Sensorimotor Cortex in C57BL/6 Mice

Background. Motor rehabilitative training improves behavioral functionality and promotes beneficial neural reorganization following stroke but is often insufficient to normalize function. Rodent studies have relied on skilled reaching tasks to model motor rehabilitation and explore factors contributing to its efficacy. It has been found that greater training intensity (sessions/day) and duration (training days) facilitates motor skill learning in intact animals. Whether rehabilitative training efficacy varies with intensity following stroke is unclear. Methods. Mice were trained preoperatively on a skilled reaching task. Following focal ischemic lesions, mice received rehabilitative training either twice daily (high intensity [HI]), once daily (low intensity [LI]), or not at all (control) to determine the effects of rehabilitative training intensity on skilled motor performance. Results. Within 7 days, the HI-trained mice achieved preischemic levels of performance. Mice receiving LI training eventually reached similar performance levels but required a greater quantity of training. Training intensity did not consistently affect the maintenance of performance gains, which were partially lost over time in both groups. Discussion. These data indicate that increased training intensity increases the rate of functional improvements per time and per training session following ischemic insult. Thus, training intensity is an important variable to consider in efforts to optimize rehabilitation efficacy.