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Le rôle de la dominance oculaire dans la boucle perception-action : une propriété à l'origine d'asymétries perceptives et motrices

Abstract : Humans present several lateral preferences, using more a given hand, foot and eye than the other one. If handedness has already been shown to influence perceptual and motor performance, the role of other lateral preferences is currently unknown. The first part of this thesis is dedicated to the study of the influence of eye dominance on visuo-motor tasks. The dominant eye, the one used to perform monocular tasks, is linked to the ipsilateral primary visual cortex. As such, it I s also linked to the contralateral hemifield. In this thesis, we thus compared performance in the contralateral and ipsilatereral hemifields relative to the dominant eye. Participants had either to make leftward and rightward saccades, a visual discrimination task, or both simultaneously. These studies have shown that the relationship between the dominant eye and the ipsilateral primary visual cortex induced a greater perceptual enhancement of visual targets presented in the contralateral than ipsilateral hemifield relative to the dominant eye. This perceptual enhancement leaded to both higher discrimination performance and higher saccade accuracy in this hemifield compared to the ipsilateral one. Thereby, we showed that eye dominance was an important property to consider in the perception-action links, leading to asymmetries between hemifields. In a second part of this thesis, we focused on the quantification of eye dominance. Indeed, contrary to handedness questionnaires which provide a percentage-based measure, tests of eye dominance only dissociate between left and right eye dominance. To assign to each participant a percentage of eye dominance, we studied the asymmetries of the saccadic system. Saccadic peak velocity is indeed higher toward the temple (i.e., rightward saccades of the right eye and leftward saccades of the left eye) than toward the nose (i.e., leftward saccades of the right eye and rightward saccades of the right eye). This asymmetry seems linked to the strength of eye dominance, as it is only observed in case of weak eye dominance. People with strong eye dominance show higher saccadic peak velocity toward the hemifield ipsilateral to their dominant eye, irrespective of the temporal or nasal nature of the saccade. In this thesis, we simultaneously tested several saccadic asymmetries, with the idea that it could provide a graduated measure of eye dominance strength. Peak velocities are also higher for centripetal (toward the straight-ahead direction) than centrifugal (away from the straight-ahead direction) saccades. Participants had to make saccades from five different starting position (to elicit centripetal and centrifugal saccades) while the movements of their both eyes were recorded (to analyze temporal and nasal saccades). The results showed (1) that both saccadic asymmetries are linked together, suggesting that they share a common structure in their neurophysiological bases, (2) that eye dominance modulates all the saccadic asymmetries tested, and (3) that the study of several saccadic asymmetries allows quantifying eye dominance strength on a percentage-based continuous model. Observation of huge saccadic asymmetries corresponded to very weak eye dominance, whereas strong eye dominance was associated to no asymmetry. All in all, in this thesis we clarified the roles of eye dominance in the perception-action loop, and we computed a graduated measure of eye dominance strength based on oculomotor performance.
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Jérôme Tagu. Le rôle de la dominance oculaire dans la boucle perception-action : une propriété à l'origine d'asymétries perceptives et motrices. Psychologie. Université Sorbonne Paris Cité, 2018. Français. ⟨NNT : 2018USPCB126⟩. ⟨tel-02518470⟩

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