Departmental Seminar: The Developing Visual Brain - from Newborns to Numeracy
Professor Oliver Braddick & Professor Jan Atkinson
Thursday, 20 October 2016, 12pm to 1pm
Lecture Theatre C, Department of Experimental Psychology, Tinbergen Building, 9 South Parks Road, Oxford
Hosted by Professor Kia Nobre
Visual development forms the basis of social and cognitive development in the first years of life. We will illustrate some key developments with a short video. We have tracked the development of visual abilities in infants and young children, to provide a unique window into the developing visual brain, both typical and atypical. Our work has helped to establish the major transition from a largely subcortical visual brain system at birth to the characteristic mechanisms of cortical vision and their control over subcortical visual responses. We have developed novel infant-friendly tests, both cortical event- related potentials measures and behavioural, to identify delays in visual development in the first year of life which are important for pattern, movement, depth perception , the cortical control of attention shifts and the timing of the onset of visuomotor and visuo-cognitive milestones. These measures have proved to be sensitive indicators of the effects of early brain injury and premature birth in predicting later neurocognitive outcomes.
Not all parts of the cortical visual system are equally vulnerable. Tests of children’s sensitivity to global form and global motion ( coherence thresholds) show that the global motion system, while starting to function early at around 2-3 months of age , is particularly impaired in a wide range of developmental disorders, both genetic and acquired (in Williams Syndrome, autism, Fragile X, congenital cataract, hemiplegia, preterm birth). This differential impairment has led us to the hypothesis of ‘dorsal stream vulnerability’ in which poor motion performance is associated with a cluster of attentional, spatial, and visuo-motor deficits. Our recent work with a large cohort of 150 typically developing children in San Diego shows that individual differences in global motion sensitivity are associated with the brain growth in an area within parietal cortex around the intraparietal sulcus, which has been widely implicated as important part of the network used attentional control and in numerosity judgements and mathematics. In addition, individual differences in motion sensitivity correlates is associated with integrity of a major white matter fibre tract linking parietal and frontal lobes, which has been implicated as an essential part of both parieto-frontal networks for attention Consistent with this, children’s global motion, but not global form, performance, is correlated with measures of mathematical achievement and numerosity judgments. We can speculate on how far-reaching these differences in early visual brain development really are, and what are the dynamics of alternative developmental trajectories.