Automated quantitative analysis of coordinated locomotor behaviour in rats.

Disturbances of motor coordination are usually difficult to quantify. Therefore, a method was developed for the automated quantitative analysis of the movements of the dyed paws of stepping rats, registered by a colour TV camera. The signals from the TV-video system were converted by an electronic interface into voltages proportional to the X- and Y-coordinates of the paws, from which a desktop computer calculated the movements of these paws in time and distance. Application 1 analysed the steps of a rat walking in a hollow rotating wheel. The results showed low variability of the walking pattern, the method was insensitive to low doses of alcohol, but was suitable to quantify overt, e.g. neurotoxic, locomotor disturbances or recovery thereof. In application 2 hurdles were placed in a similar hollow wheel and the rats were trained to step from the top of one hurdle to another. Physostigmine-induced disturbances of this acquired complex motor task could be detected at doses far below those that cause overt symptoms.