Ensemble characterivstics ofcat locovmotionand its neural control

Stabilization and mobility of the head and trunk in vervet monkeys(Cercopithecus aethiops) during treadmill walks and gallops

“…The duration of these high velocities is brief, however, falling within the period of blinks observed in this study and reported for other monkey (Macaca) species (Baker et al, 2002;Porter et al, 1993). Other studies comparing treadmill and overground locomotion in humans and quadrupeds also reveal differences, though less dramatic, in angular and linear displacements (Alton et al, 1998;Barrey et al, 1993;Nigg et al, 1995;Stolz et al, 1997;Vogt et al, 2002), as well as in temporal characteristics (e.g., Alton et al, 1998;Barrey et al, 1993;Buchner et al, 1994;Nelson et al, 1972;Stolze et al, 1997;Wetzel and Stuart, 1976;Wetzel et al, 1975) and generated forces (White et al, 1998).…”

Modulation of phase durations, phase variations, and temporal coordination of the four limbs during quadrupedal split-belt locomotion in intact adult cats

“…During a normalized cycle, here defined from successive right hindlimb contacts, there are normally eight different time periods that can be determined on the basis of the pattern of limb supports (Frigon et al 2014;Gray 1968;Hildebrand 1989;Wetzel and Stuart 1976). Individual support periods were calculated for each locomotor episode and expressed as a percentage of cycle duration (Frigon et al 2014).…”

Speed-dependent modulation of phase variations on a step-by-step basis and its impact on the consistency of interlimb coordination during quadrupedal locomotion in intact adult cats

“…Stance duration corresponded to the interval of time from paw contact to the most caudal displacement of the paw relative to the hip (Halbertsma 1983) or the shoulder, while swing duration was measured as cycle duration minus stance duration. During a normalized cycle (i.e., from successive right hindlimb contacts) there are eight different epochs that can be determined based on the pattern of limb supports (Gray 1968;Wetzel and Stuart 1976). Each support period was calculated across sessions/animals.…”

“…It also allows the animal to change locomotor speed while maintaining dynamic stability. Although a few studies have investigated interlimb coordination as a function of speed and/or the type of gait pattern in terrestrial quadrupedal mammals during overground and/or treadmill locomotion (Abourachid et al 2007;English 1979;English and Lennard 1982;Gray 1968;Maes et al 2008;Maes and Abourachid 2013;Miller et al 1975aMiller et al , 1975bWetzel and Stuart 1976), the step-by-step control of interlimb coordination with a change in speed is largely unknown. A better understanding of speed control on a step-by-step basis is crucial because one missed step can disrupt dynamic stability and lead to a fall, thus risking injury.…”

“…This can be demonstrated by plotting the durations of the stance and swing phases as a function of cycle duration and measuring the slopes of the linear regressions (Halbertsma 1983). In most terrestrial walking species, including insects, birds, rodents, reptiles, dogs, cats, macaques, and humans, the slope of the regression between the stance phase and cycle duration (r STA ) is steeper than the slope of the regression between the swing phase and cycle duration (r SW ) (Arshavskii et al 1965;Cohen and Gans 1975;Frigon et al 2013;Gabriel and Buschges 2007;Goslow et al 1973;Grillner and Dubuc 1988;Grillner and Zangger 1984;Gruhn et al 2009;Halbertsma 1983;Jacobson and Hollyday 1982;Musselman and Yang 2007;Nilsson et al 1985;Vilensky 1983;Wetzel and Stuart 1976;Williams 1981;Yang et al 2005), In other words, the stance phase varies more than the swing phase for a given change in cycle duration.…”