The Role of Task-Specificity in Functional Outcome Following Ischemic Stroke in Mice

Rodent studies have revealed that skilled-reach training can improve motor function following ischemic stroke. Currently there are three skilled-reach training tasks available. The established tasks in the field include the Single-Pellet Reaching Task (SPRT) and the Pasta-Matrix Reaching Task (PMRT). There is also a newly developed, and not yet validated, task known as the Novel Reaching Task (NRT). The present practice is to choose one of these tasks a train mice on the same task pre-stroke and post-stroke, which is a task-specific stroke behavioral intervention. One hypothesis is that mice exposed to differing tasks pre-stroke and post-stroke (a non-task specific intervention) will exhibit greater reach performance post-stroke. We believe that a non-task specific intervention best promotes functional outcome post-stroke because new learning is involved, which we predict will promote greater changes in the brain and, in consequence, improve behavioral recovery more than task-specific interventions (which involve re-learning). A supplementary hypothesis is that the NRT will promote the greatest functional outcome post-stroke because this task aims to solve the serious shortcomings of the other established tasks (SPRT and PMRT). We found no significant effects for pre-stroke and post-stroke performance between treatment groups. However, the behavioral patterns observed post-stroke suggest that non-specific intervention (specifically SPRT pre-stroke and PMRT post-stroke) results in the best reach performance post stroke. Mice trained on NRT post-stroke exhibited the worst reaching performance, suggesting that this task may be an ineffective skilled reach task to use post-operatively. However, more research must be conducted to further examine whether task-specific or non-task specific interventions best promote functional outcome.