Development of anticipatory orienting strategies and trajectory formation in goal-oriented locomotion

Abstract

In goal-oriented locomotion, healthy adults generate highly stereotyped trajectories and a consistent anticipatory head orienting behaviour, both evidence of top-down, open-loop control. The aim of this study is to describe the typical development of anticipatory orienting strategies and trajectory formation. Our hypothesis is that full-blown anticipatory control requires advanced navigational skills. Twenty-six healthy subjects (14 children: 4-11 years; 6 adolescents: 13-17 years; 6 adults) were asked to walk freely towards one of the three visual targets, in a randomised order. Movement was captured via an optoelectronic system, with 15 body markers. The whole-body displacement, yaw orientation of head, trunk and pelvis, heading direction and foot placements were extracted. Head-heading anticipation, trajectory curvature, indexes of variability of trajectories, foot placements and kinematic profiles were studied. The mean head-heading anticipation time and trajectory curvature did not significantly differ among age groups. In children, however, head anticipation was more often lacking (χ2 = 9.55, p < 0.01), and there were significant intra- and inter-subject variations. Trajectory curvature was often very high in children, while it became consistently lower in adolescence (χ2 = 78.59, p < 10(-17)). The indexes of spatial and kinematic variability all followed a decreasing developmental trend (R (2) > 0.5, p < 0.0001). In conclusion, children under 11 do not perform curvilinear locomotor trajectories as adolescents and adults do. Anticipatory head orientation and trajectory formation develop in late childhood, well after gait maturation. Navigational skills, such as path planning and shifting from ego- to allocentric spatial reference frames, are proposed as necessary requisites for mature locomotor control.

Planning of spatially-oriented locomotion following focal brain damage in humans: A pilot study

“…Importantly, participants were free to choose any path allowing them to reach a distant (visible or memorized) target (with vision or blindfolded). As previously observed in healthy adult participants [6][7][8]10], we observed very similar geometrical forms of paths across target positions and visual conditions. Remarkably, this spatial stereotypy of the locomotor trajectories was observed following brain damage, even in the most severely impaired (hemiparetic PH) patients.…”

“…The findings of this pilot study are reminiscent of those reported by Belmonti et al [10]: cognitive and motor components of human locomotion seem to evolve independently during a lifetime, with a stabilization of gait occurring earlier (around 4-5 years of age) than path planning (around 11-13 years of age in their study). When applied to focal neurological diseases affecting gait, this emphasizes the need to develop tests (i.e., adapted versions of our paradigm) allowing parallel assessment of cognitive and motor functions after stroke; this may help rehabilitation teams to better focus on the specific deficits of patients.…”

“…This suggests a dissociation between spatial cognition and sensorimotor control mechanisms at work during spatial navigation. Stereotyped locomotor trajectories were reported in adolescents and adults but not in children under 11 years [10], showing that path planning develops in late childhood (well after gait maturation), which suggests a distinct development of path planning vs gait motor stability abilities.…”

Anticipatory control and spatial cognition in locomotion and navigation through typical development and in cerebral palsy

“…19 Head anticipation was computed both as peak head deviation from trajectory (peak h), as in Grasso et al, 9 and by means of cross-correlation as the mean temporal shift between head orientation and trajectory. Variability indices were computed as in Hicheur et al…”

“…19 Head anticipation was computed both as peak head deviation from trajectory (peak h), as in Grasso et al, 9 and by means of cross-correlation as the mean temporal shift between head orientation and trajectory. Variability indices were computed as in Hicheur et al 15 Head anticipation was found in all participants, but the amplitude and timing of peak h were very variable up to the age of 11.…”