Stride time dynamics. Examples of stride time (gait cycle duration) in MPTP-treated, 3NP-treated, and saline-treated mice of forelimbs (left panels) and hind limbs (right panels). In saline-treated animals, forelimb stride variability was higher than hind limb stride variability. MPTP-treated and 3NP-treated mice exhibited significantly higher stride variability. The coefficient of variation (CV), a measure of stride-to-stride variability, was highest in the forelimbs of 3NP-treated mice.