Measurement of locomotor activity asymmetry in rats

V.Veliks, A.Gulbe, L.Cepurite, S.Nagle, and J.Aivars

Department of Human and Animals Physiology, Faculty of Biology, University of Latvia, Riga, Latvia

Work task is to approve experimental methods for dividing rats into the groups by their locomotors activity asymmetry. Groups were named in the analogy with human ‘ambidextrous’, ‘right-hand’ and ‘left-hand’. Four tests were used for these purposes – ‘tail-head behavior lateralization test’, ‘climbing-grid test’, ‘tail-suspension test’ and ‘food obtain test’. We were counting rat movements in trial during first 10 seconds, if rat had no activity, that trial was marked as ‘ambidextrous’. Each test was repeated 30 times, ‘tail-suspension’ test 10 times, ‘food obtain’ test maximum for one hour.

Two tests (‘tail-head behavior’ and ‘climbing-grid’) were very similar and showed more or less equal results. ‘Tail-suspension’ and ‘food obtain’ are different by design and few times showed different results from first two tests and between themselves.

The experiment was carried out on 40 male Wistar population rats for eight days. Tests procedure: in first five days first three tests were done, then food was removed (water ad libitum) for 2 days. At the eighth day ‘food obtain’ test was performed.

Rats distribution in groups: 17 in the ‘ambidextrous’, 14 in the ’right-hand’ and 9 in the ‘left-hand’. Rat’s social (observed preferred pattern in cage) lateralization effect was observed.

It seems that tests can’t be equal and probably their results can be weighted; also repeated trials in the test can be different, depending on the test.

Paper presented at Measuring Behavior 2005 , 5^th International Conference on Methods and Techniques in Behavioral Research, 30 August - 2 September 2005, Wageningen, The Netherlands.

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