An automated technique for the evaluation of coordinated movement deficits in rats

The effects of CNS-active drugs and neurotoxic agents are often expressed as changes in coordinated movement. In order to quantitate such changes during prolonged chemical exposures, an automated technique for the routine measurement of coordinated hindlimb movement in the rat was developed. In this test, a color tv/microprocessor-based system was used to detect and analyze the movement of one of the rat's hindpaws as the rat placed its paw from one rung to another while walking in a rotating, motor-driven wheel. Test length was 90 sec and a wheel speed of 8.2 cm/sec was employed. Results from a 12 week study involving the ip administration of acrylamide (0, 3.6, 7.2 and 14.4 mg/kg) indicated that acrylamide produced a progressive decline in coordinated hindlimb movement beginning in Wk 6 of exposure. Although some recovery was evident following the termination of exposure, the performance of the highest dose group was still inferior to controls at the end of the 6 week recovery period. These results indicate that a video-based system for the measurement of coordinated movement can provide a rapid and reliable method for the study of prolonged neurotoxic exposures.