[Evaluation of the basic characteristics of rat behavior in the "open field" test]

Heart rate, motor activity and defecation were studied in rats of the Wistar strain in 10 successive one-hour "open field" tests. Defecation and heart rate parameters decreased monotonously both from test to test and throughout one session. In motor activity a second rise was recorded at 6--12th minutes against the background of a gradual decline. A positive correlation between the total value of defecation and the heart rate in 2nd-3rd minutes of the first test was observed. At the 13th minute the motor activity positively correlated with the heart rate. Significant negative correlation between motor activity and total value of defecation appeared only at 10--11th minutes of the first test. A conclusion is drawn on twofactorial motivational basis of rats' behaviour in the "open field" test.