Neurobiologie de la perception tridimensionnelle

Three-dimensional perception (3D) of space is based on both binocular (retinal disparity) and monocular (pictorial) cues, and non retinal (oculomotor, proprioceptive, auditory, vestibular, cognitive…) cues. The horizontal retinal disparities account for the stereoscopic perception and permit fine tuned perception of contours and volumes. The vertical retinal disparity cue also plays a role in the perception of depth, in the peripheral representation of the visual field. The monocular cues such as perspective, texture gradients, shading, colors, interposition… are numerous in the environment and permit 3D perception, even in the absence of binocular cues. The non retinal cues interact with the retinal cues essentially to calibrate them according to the elements of the scene; their presence during a critical period of the post-natal development, particularly proprioceptive signals from the extraocular muscles, is essential for the optimal processing of 3D perception. All these cues are encoded to various degrees by the brain as shown by the electrophysiological studies conducted in animals and humans and also from functional imaging (fMRI) in human and non human primates.