Tuning of a Basic Coordination Pattern Constructs Straight-Ahead and Curved Walking in Humans

• Published in: Journal of neurophysiology Vol. 91; no. 4; pp. 1524 - 1535
• Main Authors: Courtine, Gregoire, Schieppati, Marco
• Format: Journal Article
• Language: English
• Published: United States Am Phys Soc 01-04-2004
• Subjects: Adaptation, Physiological; Adult; Analysis of Variance; Biomechanical Phenomena - methods; Electromyography - methods; Extremities - physiology; Functional Laterality; Gait - physiology; Head Movements - physiology; Humans; Locomotion - physiology; Male; Middle Aged; Motor Activity - physiology; Posture - physiology; Principal Component Analysis - methods; Psychomotor Performance - physiology; Time Factors; Vision, Ocular - physiology; Walking - physiology
• ISSN: 0022-3077; 1522-1598
• DOI: 10.1152/jn.00817.2003

1 Sezione di Fisiologia Umana, Dipartimento di Medicina Sperimentale, Università di Pavia, and Centro Studi Attività Motorie, Fondazione Salvatore Maugeri (Istituto di Ricovero e Cura a Carattere Scientifico), Istituto Scientifico di Pavia, I-27100 Pavia, Italy
2 Equipe de Recherche Mixte 207, Institut National de la Santé et de la Recherche Médicale, Motricité et Plasticité, Université de Bourgogne, Dijon, France
Submitted 20 August 2003;
accepted in final form 2 December 2003
We tested the hypothesis that common principles govern the production of the locomotor patterns for both straight-ahead and curved walking. Whole body movement recordings showed that continuous curved walking implies substantial, limb-specific changes in numerous gait descriptors. Principal component analysis (PCA) was used to uncover the spatiotemporal structure of coordination among lower limb segments. PCA revealed that the same kinematic law accounted for the coordination among lower limb segments during both straight-ahead and curved walking, in both the frontal and sagittal planes: turn-related changes in the complex behavior of the inner and outer limbs were captured in limb-specific adaptive tuning of coordination patterns. PCA was also performed on a data set including all elevation angles of limb segments and trunk, thus encompassing 13 degrees of freedom. The results showed that both straight-ahead and curved walking were low dimensional, given that 3 principal components accounted for more than 90% of data variance. Furthermore, the time course of the principal components was unchanged by curved walking, thereby indicating invariant coordination patterns among all body segments during straight-ahead and curved walking. Nevertheless, limb- and turn-dependent tuning of the coordination patterns encoded the adaptations of the limb kinematics to the actual direction of the walking body. Absence of vision had no significant effect on the intersegmental coordination during either straight-ahead or curved walking. Our findings indicate that kinematic laws, probably emerging from the interaction of spinal neural networks and mechanical oscillators, subserve the production of both straight-ahead and curved walking. During locomotion, the descending command tunes basic spinal networks so as to produce the changes in amplitude and phase relationships of the spinal output, sufficient to achieve the body turn.
Address for reprint requests and other correspondence: M. Schieppati, Centro Studi Attività Motorie (CSAM), Fondazione Salvatore Maugeri (IRCCS), Istituto Scientifico di Pavia, Via Ferrata 8, I-27100 Pavia, Italy (E-mail: mschieppati{at}fsm.it ).