title: Gaze anticipation during human locomotion.
abstract: During locomotion, a top-down organization has been previously demonstrated with the head as a stabilized platform and gaze anticipating the horizontal direction of the trajectory. However, the quantitative assessment of the anticipatory sequence from gaze to trajectory and body segments has not been documented. The present paper provides a detailed investigation into the spatial and temporal anticipatory relationships among the direction of gaze and body segments during locomotion. Participants had to walk along several mentally simulated complex trajectories, without any visual cues indicating the trajectory to follow. The trajectory shapes were presented to the participants on a sheet of paper. Our study includes an analysis of the relationships between horizontal gaze anticipatory behavior direction and the upcoming changes in the trajectory. Our findings confirm the following: 1) The hierarchical ordered organization of gaze and body segment orientations during complex trajectories and free locomotion. Gaze direction anticipates the head orientation, and head orientation anticipates reorientation of the other body segments. 2) The influence of the curvature of the trajectory and constraints of the tasks on the temporal and spatial relationships between gaze and the body segments: Increased curvature resulted in increased time and spatial anticipation. 3) A different sequence of gaze movements at inflection points where gaze plans a much later segment of the trajectory.
authors.affiliation: LPPA, UMR7152, CNRS-Collège de France, 11, Place Marcelin Berthelot, 75005, Paris, France. delphine.bernardin@college-de-france.fr
authors.forename: Delphine
authors.initials: D
authors.lastname: Bernardin
authors.forename: Hideki
authors.initials: H
authors.lastname: Kadone
authors.forename: Daniel
authors.initials: D
authors.lastname: Bennequin
authors.forename: Thomas
authors.initials: T
authors.lastname: Sugar
authors.forename: Mohamed
authors.initials: M
authors.lastname: Zaoui
authors.forename: Alain
authors.initials: A
authors.lastname: Berthoz
mesh_terms: D000328:Adult; D000465:Algorithms; D059031:Anticipation, Psychological / Q000502:physiology*; D002138:Calibration; D003627:Data Interpretation, Statistical; D005133:Eye Movements / Q000502:physiology; D005260:Female; D005403:Fixation, Ocular / Q000502:physiology*; D005528:Foot / Q000502:physiology; D019416:Head Movements; D006801:Humans; D008124:Locomotion / Q000502:physiology*; D008297:Male; D055815:Young Adult