That is, parafoveal and peri-foveal regions would probably be over-represented as these regions of the retina would be more often trained on the intended environmental object of interest and, in turn, the representation of the fovea should be partially reduced. We have derived a simple ‘Altered Cortical Magnification Model’, using the observed values from the work of Adams and Horton to illustrate the potential impact of such remapping on the cortical representations for inputs at various eccentricities

(see Fig. 1). This simple model makes some clear predictions. Spatial representation around the fovea would be expected to lead to only marginal changes in the absolute extent of cortex responding to central stimulation (given the truly enormous tract of V1 dedicated to the central region) whereas the Smad3 signaling relative changes in representation outside of the parafoveal

region would be expected to substantially Oligomycin A increase the extent of cortex responding to presentations at this eccentricity (given the initially very sparse representations at such eccentricities). Very few studies have examined how altered eye movements and resultant fixation patterns might influence cortical processing of visual information in ASD (Dalton et al., 2005). Given the close link between eye movements and visual cortical representations, as well as the observed deficits in oculomotor control in autism, we hypothesized that individuals with autism would exhibit alterations in the early see more cortical representations of peripheral visual space. To test this, VEPs as well as visually evoked spread spectrum response potentials (VESPA)

(Lalor et al., 2006, 2009; Frey et al., 2010) were obtained for stimuli presented either at the center of gaze or at a parafoveal location. Because there is an ongoing debate on whether impaired magnocellular processing contributes to visual processing differences in ASD (Spencer et al., 2000; Milne et al., 2002; Robertson et al., 2012) and the proportion of magnocellular cells increases with increasing retinal eccentricity (Connolly & Van Essen, 1984) we also employed stimuli specifically biased towards activation of magnocellular neurons (Butler et al., 2007; Foxe et al., 2008; Lalor & Foxe, 2009). In visual cortex, magnocellular neurons feed predominantly into the dorsal stream, known as the ‘where’ pathway for its role in movement processing and object localization (Mishkin & Ungerleider, 1982). The combination of stimuli biased towards different visual pathways and different stimulus eccentricities was expected to yield a sensitive measure of visual cortical representation in ASD. Twenty-two children with a diagnosis of ASD (one female) between 7 and 17 years of age (mean = 11.3; SD = 2.7) and 31 typically developing (TD) children (11 female) between 6 and 18 years of age (mean = 12.3; SD = 3.0) participated in this study.