title: Visual straight-ahead preference in saccadic eye movements.
abstract: Ocular saccades bringing the gaze toward the straight-ahead direction (centripetal) exhibit higher dynamics than those steering the gaze away (centrifugal). This is generally explained by oculomotor determinants: centripetal saccades are more efficient because they pull the eyes back toward their primary orbital position. However, visual determinants might also be invoked: elements located straight-ahead trigger saccades more efficiently because they receive a privileged visual processing. Here, we addressed this issue by using both pro- and anti-saccade tasks in order to dissociate the centripetal/centrifugal directions of the saccades, from the straight-ahead/eccentric locations of the visual elements triggering those saccades. Twenty participants underwent alternating blocks of pro- and anti-saccades during which eye movements were recorded binocularly at 1 kHz. The results confirm that centripetal saccades are always executed faster than centrifugal ones, irrespective of whether the visual elements have straight-ahead or eccentric locations. However, by contrast, saccades triggered by elements located straight-ahead are consistently initiated more rapidly than those evoked by eccentric elements, irrespective of their centripetal or centrifugal direction. Importantly, this double dissociation reveals that the higher dynamics of centripetal pro-saccades stem from both oculomotor and visual determinants, which act respectively on the execution and initiation of ocular saccades.
authors.affiliation: Université de Toulouse, Centre de Recherche Cerveau et Cognition, Toulouse, France.|Centre National de la Recherche Scientifique, Toulouse Cedex, France.
authors.forename: Damien
authors.initials: D
authors.lastname: Camors
authors.affiliation: Université de Toulouse, Centre de Recherche Cerveau et Cognition, Toulouse, France.|Centre National de la Recherche Scientifique, Toulouse Cedex, France.
authors.forename: Yves
authors.initials: Y
authors.lastname: Trotter
authors.affiliation: Inserm U975, Movement disorders and basal ganglia, Hôpital de la Salpêtrière, Paris, France.|Université Pierre &Marie Curie-Paris 6, CNRS UMR 7225, CR-ICM, UMR S975, Paris, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Pouget
authors.affiliation: Institut de Neurosciences Translationnelles de Paris, IHU-A-ICM, Paris, France.
authors.forename: Sophie
authors.initials: S
authors.lastname: Gilardeau
authors.affiliation: Université de Toulouse, Centre de Recherche Cerveau et Cognition, Toulouse, France.|Centre National de la Recherche Scientifique, Toulouse Cedex, France.
authors.forename: Jean-Baptiste
authors.initials: JB
authors.lastname: Durand
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D010775:Photic Stimulation; D011930:Reaction Time; D012438:Saccades / Q000502:physiology*