Basic neuroscienceAn automated task for the training and assessment of distal forelimb function in a mouse model of ischemic stroke

- We present an automated assay of distal forelimb function.
- This assay precludes compensation and quantifies multiple aspects of the reach and grasp motion.
- Training, assessment, and analysis on this assay are automated to produce reliable, precise, and richly informative data while requiring relatively little time investment.
- We show that photothrombotic stroke of the cortical motor forelimb representation causes long-term impairment in multiple aspects of this task through 22 weeks of weekly practice and assessment.

BackgroundBehavioral models relevant to stroke research seek to capture important aspects of motor skills typically impaired in human patients, such as coordination of distal musculature. Such models may focus on mice since many genetic tools are available for use only in that species and since the training and behavioral demands of mice can differ from rats even for superficially similar behavioral readouts. However, current mouse assays are time consuming to train and score, especially in a manner producing continuous quantification. An automated assay of mouse forelimb function may provide advantages for quantification and speed, and may be useful for many applications including stroke research.New methodWe present an automated assay of distal forelimb function. In this task, mice reach forward, grip and pull an isometric handle with a prescribed force. The apparatus partially automates the training process so that mice can be trained quickly and simultaneously.ResultsUsing this apparatus, it is possible to measure long-lasting impairment in success rate, force pulled, latency to pull, and latency to success up to 22 weeks following photothrombotic cortical strokes in mice.Comparison with existing method(s)This assessment measures forelimb function as do pellet reach tasks, but it utilizes a different motion and provides automatic measures that can ease and augment the research process.ConclusionsThis high-throughput behavioral assay can detect long-lasting motor impairments, eliminates the need for subjective scoring, and produces a rich, continuous data set from which many aspects of the reach and grasp motion can be automatically extracted.