Do Results of the Open Field Test Depend on the Arena Shape?

The open field test (OFT) is one of the main methods used for the estimation of behavioral indices and emotionality levels in animals. This test is widely used in toxicological and pharmacological studies. The question of whether the arena shape influences the results of testing remained open. This is why we compared the results of the mentioned test using one and the same species of laboratory animals (rats), identical conditions of testing, and arenas of nearly the same area but of a round or square shape. Significant differences were found in only two examined parameters, frequency of realization of the burrow reflex and intensity of internal horizontal motor activity; other indices showed nearly no considerable differences. Thus, it can be concluded that the results of behavioral studies carried out under the above two conditions are rather similar to each other in their adequacy.