Skilled forelimb reaching in Wistar rats: evaluation by means of Montoya staircase test

Experimental animals have been used as models for several neurological disorders; their performance in behavioral tests is useful in determining the success of lesion repair procedures and assessing functional recovery. The staircase test is a behavioral test that consists in reaching for food inside a special box and allows for a sensitive measure of skilled reaching by each limb in an independent manner. In most laboratories in the south of Brazil, Wistar rats are used for the study of experimental stroke, hypoxia and peripheral neuropathy, but most studies with the staircase test have used other strains such as Sprague-Dawley and Long-Evans. Because skilled reaching, grasping and performance can differ among strains, the purpose of the present study was to characterize the performance of Wistar rats in the staircase test and determine the effect of median and ulnar nerve crush. Our results with Wistar rats on the staircase test showed that: similar to other strains, Wistar animals can display high performance after 2 weeks of training; the number of animals that attained the inclusion criterion increased by 10% with longer times of training; the stricter criterion of 15 pellets taken can be adopted as study inclusion criterion; the test has an unquestionable value in assessing lateralized deficits, as evidenced by the lack of performance deficit of the non-manipulated forelimb at any time point. These results extend the understanding about the performance of Wistar rats in the staircase test, which will be used for the best training and research using this strain.