Andrew J Parker
Department of Physiology,Anatomy and Genetics
University of Oxford, UK
"Searching for sites and neural correlates of cyclopean perception"
Institute of Psychology,Faculty of Humanities and Social Sciences
Pázmány Péter Catholic University, Budapest, Hungary
"The role of experience in the development of binocular vision in infants"
Neuroscience Division,School of Biosciences
Cardiff University, UK
"Effects of dark exposure on visual cortex plasticity"
David P Piñero
Department of Optics, Pharmacology and Anatomy
University of Alicante, Spain
"Visual rehabilitation in adult amblyopia using perceptual training"
The nervous system brings together the independent signals from the two eyes into a single representation of objects in the visual world around us. Helmholtz and Julesz termed this process 'cyclopean perception', referring to the mythical single-eyed giants (Cyclops) of classical Greece. Andrew Parker (Oxford) will review recent progress towards identifying the neural sites and correlates of cyclopean perception. The implications of these findings for understanding clinical conditions of disordered binocular vision will be explored. The ontogenetic development of cyclopean perception requires visual experience, which begins right after birth and reshapes neuronal connections in the visual cortex. In humans, most of the cortical connections necessary to process binocular signals are formed between the 3rd and 6th postnatal months. Ilona Kovács (Budapest) and her colleagues demonstrate that earlier onset of visual experience provided by prematurity
starts the developmental processes earlier and the maturation of the cortex is completed sooner, exactly at the same postnatal age as in mature infants. These data further support that this type of neuronal plasticity is highly dependent on visual inputs.
Binocular development is also sensitive to the quality of the visual input entering the two eyes and either monocular deprivation or rivalizing images prevent the formation of appropriate neuronal connections leading to amblyopia and lack of cyclopean perception. Recent evidence suggests that dark exposure may reinstate visual cortex plasticity after closure of the critical period. Frank Sengpiel (Cardiff) will present work investigating the effects of a week of dark exposure on the recovery from a month of monocular deprivation in mouse V1. Functional imaging revealed that ocular dominance in V1 of mice that had received dark exposure recovered more quickly than of mice that had not, but the eventual level of recovery was similar in both groups. The percentage of parvalbumin positive interneurons cells surrounded by perineuronal nets, a structural brake on plasticity, was lower in mice with than those without dark exposure. Overall, dark exposure causes a modest enhancement of mouse visual cortex plasticity. New approaches for amblyopia treatment have been defined in the last years that can be grouped into perceptual and dichoptic training. Several studies have provided some scientific evidence of the use of these types of treatment in children, but the scientific evidence is scarce in adults. David Piñero (Alicante) will show results obtained by using the Amblyopia iNet software based on perceptual visual training.