We therefore examined the relation between these ADOS scores and the relative P1 response to peripheral visual stimulation using the ‘robustfit’ regression function (Matlab 7.5). As most visual behaviors are coded in the first two sections (‘Unusual Sensory Interest in Play Material/Person’ and ‘Hand and Finger and Other Complex Mannerisms’) of the SBRI category, we examined these more closely. The algorithm scores in these sections are integer values between 0 and 2, which makes it difficult to use regression methods. We therefore divided ASD participants into groups with high and low relative amplitudes and compared their codes in these sections using the non-parametric Wilcoxon rank-sum
test. For stimuli presented at the center of gaze, both the VEP and VESPA electrophysiological responses Volasertib solubility dmso were highly similar between groups, and amplitudes of
early visual processing components (C1, P1, and N1) did not differ (Fig. 3, left column). No statistically significant differences in either amplitude or latencies (all P > 0.22) were detected, indicating that visual processing of simple stimuli at central locations, as assessed by our method, was intact in ASD children. However, for stimuli presented in the periphery, we found clear differences between ASD and TD groups selleck (Fig. 3, right column). During the P1 timeframe, the planned comparison t-tests revealed a significant difference for the VEP and Full-Range VESPA in the periphery, with ASD children exhibiting larger amplitudes (t41 = 2.38, P = 0.022 and t40 = 2.27, P = 0.029, respectively). The difference in the planned comparison P1 timeframe for the peripheral Magno VESPA was not significant (t34 = 0.5,
P = 0.62). However, post hoc running t-tests revealed that in the timeframe from 155 to 180 ms the amplitude of the ASD group’s response was significantly medroxyprogesterone larger than for the TD group. The latency of the P1 peak was significantly later in ASD (median latency 155 compared with 134 ms). However, this did not indicate a delayed onset, but rather a temporal extension of the P1 component (Fig. 3F). Taken together, these results provided evidence for processing differences between TD and ASD participants for peripheral stimulation during the P1 timeframe. The post hoc test also revealed additional differences for peripheral conditions. We found a significantly more negative Full-Range VESPA amplitude from 145 to 180 ms, during the N1 component timeframe (Fig. 3B), and a significantly more negative VEP amplitude in the time range from 210 to 255 ms (Fig. 3D) in the ASD group. Note that even though responses to visual stimuli are generally found to have shorter latencies in the magnocellular pathway, the peripheral Magno VESPA responses were delayed by more than 20 ms compared with the Full-Range VESPA.