001, rank-sum = 67) higher values (mean = 1.33) than those with low relative scores (mean = 0.6). Taken together, these findings indicate that the peripheral Full-Range VESPA P1 amplitude and clinical measures of unusual sensory interest are closely related.

Examining the waveforms suggested that that the timeframe around the P1 component might be the most informative regarding differences between ASD and TD children. As the channels selected for depicting the waveforms represented only a very small subset of the information obtained in the experiments, we also analysed the topographical distribution of activity in the Talazoparib in vitro P1 timeframe. For three of the four VESPA conditions, with the exception of the peripheral Magno VESPA, the topographic distribution of activity was marked by a single midline distribution over occipital scalp, while the VEP response was characterized by bilateral occipital–parietal

foci (Fig. 5A). The finding that the VESPA P1 amplitude was more constrained over central occipital areas (Fig. 5B and C) is fully in line with previous studies in adult participants (Lalor et al., 2012; Murphy NVP-BEZ235 et al., 2012). The analysis of P1 topographies showed that, for each experimental condition, the topographical patterns of activation were highly similar between ASD and TD children. For peripheral stimulation, the amplitudes in the P1 timeframe over occipito-parietal areas were generally larger in the ASD group. The topographies indicated that early visual cortical areas have increased response amplitudes for peripheral stimuli in children with ASD. The current study employed different types of low-level visual acetylcholine stimuli. The Magno VESPA stimuli were designed based on prior knowledge about characteristics of magnocellular neurons. To confirm that the stimuli were

strongly biased towards activating the dorsal pathway, we localized the visual activation for centrally presented Full-Range and Magno VESPA stimuli using the MUSIC technique. The pattern of current sources for the P1 component of the VESPA was the same for both ASD and TD children. While the Full-Range VESPA stimuli activated regions around the occipital pole, we found current sources to be stronger in areas more dorsal for the Magno stimuli (Fig. 6). The MNI coordinates of the peak activity in the MUSIC map for the Full-Range stimuli were x = 3, y = −98, z = 5 for the TD and x = 13, y = −97, z = 5 for the ASD group. In the case of the Magno stimuli the MNI coordinates were x = −7, y = −76, z = 18 for the TD and x = −11, y = −80, z = 34 for the ASD group. This clear shift of current sources towards more dorsal areas for the Magno stimuli provided evidence that these stimuli biased the response toward the dorsal stream.