A computerized grid walking system for evaluating the accuracy of locomotion in rats.

A microcomputer-based system employing photoelectric devices to record rat movements and footfalls in the grid walking test paradigm was developed and evaluated. Behavioral data obtained from the system were: distance traversed on the grid, time taken to traverse the distance, number of footfalls, times of footfalls, positions of footfalls, durations of footfalls, and whether the footfall was due to a hind or a fore limb. Validation of the system was performed by comparing the data obtained from the videotape analysis with that obtained from the computerized system. Correlation coefficients between the data obtained from the two methods were found to be 0.92 for one observer, 0.84 for a second observer, and 0.88 with the mean of the two observers. An experimental study in which a group of rats was administered dorsal hemisection lesions of the spinal cord was also conducted. Animals in the lesion group took the same amount of time to cross the runway as the control animals, but made more footfalls per crossing and had longer durations per footfall. The studies validate the capacity of the computerized system to efficiently detect fine locomotory deficits, suggesting that it is a viable tool for the evaluation of neurological dysfunctions in experimental rats.