EyeSee - Eye movements and vision: coupling between saccadic adaptation and visuo-spatial perception

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Correct execution of purposeful behavior is essential for individuals in their daily activities. Thanks to goal-directed movements of eyes and whole-body, we perceive, explore, sample and modify our environment and can exchange and communicate with others. The current project aims at studying the behavioral processes and neuronal mechanisms behind the perception/action coupling. The oculomotor system is a privileged model of sensorimotor transformations because it strongly determines human performance in vision, the dominant sensory modality, notably through saccades to scan our visual environment. Saccadic adaptation mechanisms aim to maintain the accuracy of saccades by reducing errors in case of enduring perturbations to the visuo-oculomotor system, be it of physiological or pathological origin. Saccadic adaptation is thus thought to maintain efficient visual exploration. To date, both partner applicants have provided critical-but-separate contributions to the field. Pelisson (Partner 1) has revealed the effects of saccadic adaptation onto visually-directed eye and hand movements, and has started to unravel the so-far largely neglected role of the cerebral cortex in adaptation. Lappe (Partner 2) has revealed that saccadic adaptation can lead in certain conditions to changes in our perception of the location of a visual target when flashed just before a saccade, or even in stationary eye conditions (ocular fixation). Altogether, these findings indicate that saccades adaptation may not only occur through motoric changes, but also through changes in sensory representations, and may aim not only at better aligning the eye with the target, but also at maintaining consistency between visual and oculomotor representations. The present project aims at deciphering the properties and the anatomical and electrophysiological substrates of the specific effects of saccadic adaptation on visual perception, by means of complementarity approaches of computational modelling and psychophysics in cerebellar patients, in healthy subjects coupled with tDCS and fMRI, and in implanted patients coupled with iEEG. This original collaborative effort will provide crucial fundamental knowledge, with high potential for clinical applications on rehabilitation of visual perception deficits through eye movement training. The present project is based on a collaboration between the Lyon and Muenster partners built upon the solid foundation created by years of intense research on common topics and frequent scientific exchanges. Its ambition is to provide a substantial step forward into our knowledge of the mechanisms and brain substrates of oculomotor adaptation and of its consequences for visuo-spatial perception, providing a critical step for future translational research to clinics for rehabilitation of visuo-attentional deficits.