The use of behavioral test batteries: effects of training history

Our laboratory uses a specific test battery for the initial assessment of phenotypic behavioral differences of transgenic, knockout, and inbred strains of mice. Our standard battery includes: open field activity, light-dark exploration, rotarod, prepulse inhibition (PPI), acoustic startle habituation, conditioned fear, Morris water maze, and hot plate. Tests are run in the order listed, from least invasive to most invasive, to decrease the chance that behavioral responses are altered by prior test history. The studies presented here were designed around two questions. The first study asks if differences exist between mice that have undergone testing on different tasks and mice that are naïve to the test experience. The second study asks if the test order affects how an animal performs on subsequent tests. In the first experiment, C57BL/6J male mice were evaluated on all of the tests described above. The behavior of these 'test battery' mice was compared to aged matched naïve mice that were only tested on one test from the battery. Results indicate that on some tests, the behavior of 'test battery' mice was significantly different from the behavior of naïve mice, while on other tests there were no differences. For example, test battery mice responded differently in the open-field, rotarod, and hot-plate test, but behaved similar on the PPI and conditioned fear. Experiments in the second study were performed on male 129/SvEvTac (129S6) and C57BL/6J male mice. An abbreviated battery of tasks was used and the results suggest that certain test variables are sensitive to test order, whereas others are resistant. These two studies demonstrate that some behavioral tests appear to be sensitive to previous testing experience, while other tests are immune.