The development of perceptual spatial interactions: psychophysics and neurophysiology

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Research on visual development has long been guided by two hypotheses: visual development is complete during infancy and the different visual functions (e.g., contrast sensitivity, acuity, motion perception, form perception) mature at the same rate. This explains why there are few studies of visual development beyond infancy. A series of recent studies from our laboratory cast serious doubt about these two hypotheses. Indeed, we found that several visual functions do not attain maturity before late childhood or even early adolescence and that not all visual functions mature at the same rate. In an attempt to better understand the mechanisms of this protracted maturation, the proposed research will investigate the development of the functional architecture of perceptual lateral interactions. Spatial lateral interactions occur when the perception of a visual target is altered by the presence of neighbouring elements. Understanding the rules that underlie the development of lateral interactions provides critical information about the make-up of the visual system. Specifically, by means of psychophysical and neurophysiological (Visual Evoked Potentials) methodologies, we endeavour to study the development of lateral spatial interactions in order to understand the rules of 1) the suppressive responses of visual neurons, 2) their orientation and spatial frequency tuning, and 3) their contrast gain control. The research supported by the current proposal is important for our understanding of human brain development and its functional organization and plasticity. This will be of great interest for researchers in the field of neurosciences, biology, engineering, and medicine. This research will enable Canadian researchers to gain international leadership in the field of developmental neurosciences.