Measuring Behavior 2005: Silva et al.

Automatic computer vision monitoring and evaluation of mouse motor function

M. Silva, T. Leroy, S. Quanten, J.-M. Aerts and D. Berckmans

Laboratory for Agricultural Buildings Research, Department of Agro-Engineering and -Economics, Catholic University of Leuven, Kasteelpark, Leuven, Belgium

In current research on laboratory animals, observing their dynamic behavior or locomotion is a labour-intensive task. Continuous monitoring in an automatic way can give a more detailed view on their condition and coordination ability.

The objective of this paper is to show the progress in the development of an automated mouse observation system, based on a conventional test for motor function evaluation.

For the experiments, three SWISS mice were used. One at a time was placed in the test setup, consisting of a plexi-glass cage (53x34.5x26cm) and two fluorescent bulbs at a distance of 23cm from the cage for proper illumination. The transparent cage allowed images to be captured from underneath the cage, so additional information could be obtained about the position of the limbs of the mice for gait reconstruction.

The mouse’s visible contour was extracted using edge segmentation. Next, colour segmentation was applied within the recovered mouse region to measure the position of the mouse’s paws, which showed up as small pink spots. The paws were classified as either front left/right or hind left/right by looking at their position relative to the contour of the mouse.

The accuracy was between 78-85% for the x-coordinates of the paw positions and between 88% and 91% for the y-coordinates of the paw positions.

This technique can be integrated in a regular open field test, where the trajectory and motor function of a free-moving mouse are measured simultaneously.

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.