Chronic 30-Hz deep cerebellar stimulation coupled with training enhances post-ischemia motor recovery and peri-infarct synaptophysin expression in rodents

Background: Over 500 000 Americans have strokes every year, making stroke the leading cause for disability in the United States and in the industrialized world. New treatments to improve poststroke motor recovery are needed. Objective: To investigate a novel approach for enhancing motor recovery that involves chronic, electrical stimulation of ascending cerebellar output combined with motor training. Methods: Adult Sprague-Dawley rats underwent unilateral endothelin-1 injections in the dominant cerebral cortex and placement of a chronic stimulating electrode in the contralateral lateral cerebellar nucleus. After 1 week, the animals were separated into 2 groups (STIM1 and STIM2), matched for poststroke motor performance in the pasta matrix task. At 2 weeks post-ischemia, the treatment phase was initiated, with animals in the STIM1 group receiving pulsed, 30-Hz stimulation for 12 hours/day. Motor training continued for both groups over 3 to 5 weeks. Results: A total of 23 animals were examined after 3 weeks of treatment. STIM1 animals showed a significant improvement in motor function compared with postischemia baseline performance as well as in comparison with the STIM2 group. Immunohistochemistry revealed a significant increase in the perilesional expression of synaptophysin for the STIM1 vs the STIM2 animals. Conclusion: These results indicate that chronic activation of ascending cerebellofugal pathways enhances motor recovery after focal cortical ischemia. The recovery was associated with an increase in perilesional cortical plasticity relative to nontreated controls.