Intrinsic limb morpho‐dynamics and the early development of interlimb coordination of walking in a quadrupedal primate

• Published in: Journal of zoology (1987) 2017-03, Vol.301 (3), p.235-247
• Main Authors: Druelle, F., Berillon, G., Aerts, P.
• Format: Article
• Language: English
• Subjects: coordination; Evolution; limb development; locomotion; Morphology; morpho‐dynamics; natural pendular period; ontogeny; Papio anubis; Primates; Zoology
• ISSN: 0952-8369; 1469-7998
• DOI: 10.1111/jzo.12423

We question the developmental changes of the temporal aspects of quadrupedal walking and how these relate to the intrinsic morphological (size, shape) and dynamical (inertia) properties of the limbs and body. Indeed, during ontogeny of altricial species, a dependent infant develops toward autonomy. Interlimb coordination is likely to be mediated by the neurological system (central pattern generators and/or supraspinal control), whereas the mechanical parameters of limbs and body appear to influence the locomotor optimization of gaits. We studied six captive baboons at two instants in their development, when they just begin foraging independently and when they are autonomous, in order to collect, in parallel, morphometrics and temporal parameters of voluntary quadrupedal walking. The natural pendular period (NPP) is put forward to represent the limb's intrinsic morpho‐dynamics; the position of the body center of mass as the morpho‐dynamics of the body. The main results reveal that fore‐ and hindlimbs, at the level of the convergence of the NPP, have a significant and positive impact on the interlimb coordination pattern. This probably facilitates, very early in development, the control of the coordination. Nevertheless, because an improved control of the interlimb coordination points at a proceeding neuromotor maturation as well, neuromotor control appears to become gradually important relatively to the intrinsic morpho‐dynamics of the limbs during infancy. These findings are of importance in the context of the evolution of the locomotor developmental processes in primates. We question the developmental changes of the temporal aspects of quadrupedal walking in primate, and how these relate to the inertial properties of the limbs and body. For this aim, we studied six captive baboons at two instants in their development, when they just begin foraging independently and when they are autonomous. The main result reveals that the natural pendular period convergence of the limbs has a significant and positive impact on the interlimb coordination pattern. Therefore, while the control of the limbs is in progress through the gradual expression of the corticospinal system, interlimb coordination of quadrupedal walking appears to be (initially) facilitated by intrinsic limb morpho‐dynamics, making it an important determinant in the process of quadrupedal learning.