Development of locomotion in the rat--spatiotemporal footfall patterns.

Footfall patterns during locomotor ontogeny have been observed in Wistar rats 10-30 days old. These reveal that, even at 22 days, the paw contacts are both spatially and temporally unlike those of the adult. In the adult there is a precise presentation sequence involving early soft contact of tactile sensitive forepaw parts that may be important in tactile locomotor guidance and which is not fully established even at 22-30 days. The hindpaw contact pattern is also not yet adult-like involving a greater incidence of early toe contact. It is suggested that, only after day 15, when the forelimb is no longer the major weight-bearing limb, can it start to be developed for the fine discriminative touch required for tactile guidance of limb placement. Some further time is necessary for adult patterns to be achieved.