A computer-aided procedure for measuring swim rotation

As a rat or mouse swims in a small cylinder, its movements are tracked by an observer using a joystick, and the information is sent to a Macintosh computer. The swimming circle is broken into quadrants. The sequence of quadrants entered and the time spent in each quadrant are recorded as the basic data. From the data set one can extract full or partial turns, clockwise or counterclockwise rotations, total activity, and speed of swimming clockwise and counterclockwise. Two laterality indices, one based on full turns and the other on partial turns, are calculated. Test-retest reliability for rats and mice for 3-minute and 5-minute observation intervals are reported.