Kinematic analyses of air-stepping in normal and decerebrate preweanling rats

Air-stepping in neonatal rats: A comparison of L-dopa injection and olfactory stimulation.

“…Differences in the age of the rats (PD 3 instead of PD 5) or in the variable measured (the foot position instead of the ankle and elbow angle) may have contributed to this difference. A recent article by Stehouwer and Van Hartesveldt (2000), however, reported a phase delay between diagonal legs that was observed in control and decerebrate PD 5 rats, which is fully consistent with the coupling observed in the present study.…”

“…The ability of the L-dopa injection to induce sustained motor activities in pups made it an efficient method for studying the development of locomotion. The obstinate locomotor activity induced is unnatural, and Stehouwer and Van Hartesveldt (2000) have presented it as a model of a chemically decerebrate rat. There are ongoing questions as to the actual status of this behavior.…”

“…The ambient temperature may also explain the lower rate of L-dopa-induced air-stepping (1.5 cycles/s) compared with other published L-dopa studies, where the experimental device was placed in an incubator. Previous studies have reported stepping frequencies of 1.5 and 3.0 cycles/s in PD 0 and PD 5 rats, respectively (Stehouwer et al, 1994;Stehouwer & Van Hartesveldt, 2000;Van Hartesveldt et al, 1991), but it was difficult to compare data as 3-day-old rats had not been used. Temperature was not, however, responsible for the difference in the stepping rate when the drug or odor was used; the change in the L-dopa-induced stepping rate measured at the be- ginning and end of the experiment was insignificant compared with the changes produced by the other two stimuli.…”

“…The method has been used to analyze changes in interleg coordination in relation to age (McCrea, Stehouwer, & Van Hartesveldt, 1994; Stehouwer et al, 1994), in relation to joint movements (Stehouwer et al, 1994), and in relation to muscle activities (Tucker & Stehouwer, 2000). When applied to decerebrate pups, the method helped develop the hypothesis that gait maturation depends solely on the development of brainstem and spinal chord circuits (Iwahara, Van Hartesveldt, Garcia-Rill, & Skinner, 1991; Stehouwer & Van Hartesveldt, 2000). The relevance of this method suffers, however, because of questions about the meaning of pharmacologically induced activities.…”

“…The relevance of this method suffers, however, because of questions about the meaning of pharmacologically induced activities. Air-stepping has often been compared to swimming, but its characteristics are closer to the activity of chemically decerebrate rats (Stehouwer & Van Hartesveldt, 2000).…”