Kinematic analysis of limb position during quadrupedal locomotion in rats.
A test of locomotor behavior using the coordinates of ipsilateral limb positions of rats walking on a moving treadmill is described. Specific points on the forelimb and hindlimb were digitized from video records for 20-sec continuous sequences of locomotion, and step periods and step distances were calculated. The extent to which a given limb position would predict its own position--or the position of another limb--at different points in time was mathematically determined by autocorrelation and cross-correlation, respectively. Autocorrelation of position data was performed using a three-step window and the standard formula for correlating phasic data. A novel method of data preparation, which included normalization of the step data to eliminate variability introduced by differences in step period length, was used prior to cross-correlations of forelimb to hindlimb positions. Rats walking at 0.10, 0.15, and 0.25 m/sec had high limb autocorrelations, comparable forelimb/hindlimb phase relationships, and consistently high average cross-correlation coefficients. This analysis has resulted in the quantification of rat locomotor behavior in terms of the degree of limb movement rhythmicity and the strength of the forelimb/hindlimb coordination, and has provided baseline data for comparisons with spinal cord-injured rats that have retained or recovered alternating hindpaw movements.
Broton
J G
JG
Miami Project to Cure Paralysis, University of Miami School of Medicine, Florida 33136, USA.
Nikolic
Z
Z
Suys
S
S
Calancie
B
B
D000818:Animals; D005260:Female; D006614:Hindlimb / Q000502:physiology*; D007700:Kinetics; D008124:Locomotion / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D016138:Walking / Q000502:physiology*