Association between sensory reactivity and neural activity of orienting and cognitive control in autism spectrum disorders
Atypical sensory reactivity to visual and/or auditory stimuli is prevalent among individuals with autism spectrum disorders (ASD). Data from cognitive neuroscience research suggests that changes in attention can alter sensory processing at several levels of analysis, and thus could be contributing to changes in sensory reactivity. Furthermore, attentional pathways are modulated by the individual difference variable of working memory capacity (WMC). This study examined the relationship between sensory reactivity, individual difference, and auditory attention in ASD by using electroencephalography technique. Participants (n=25, 12 with ASD and 13 age- and IQ-matched controls) completed a sensory profile, complex operation span task for working memory capacity (WMC), and performed a modified 3-stimulus (target, non-target, and distractor) oddball task under varying perceptual load (high or low). Event-related potential (ERP) analysis assessed early sensory processing (P50, ~50ms latency; N100, ~100ms latency), cognitive control (N200, ~200ms latency), and attentional processing (P3a and P3b, ~300ms latency). Behavioral data demonstrates participants with ASD and neurotypical performed similarly on WMC and auditory target detection, but diverged in sensory profiles. In target processing under high perceptual load did not enhance P3b latency in those with ASD suggesting increased perceptual capacity compared to neurotypicals. No neurophysiological difference between groups in target data suggests intact top-down control in people with and without ASD. Early and late orienting ERPs (P50, N100, P3a) in non-target processing were unaffected by perceptual load. Robust differences in distractor processing were observed between groups in both early (N100) and late (N200) neural correlates of auditory attention. N100 responses in participants with ASD were strongly attenuated by increasing perceptual load compared to neurotypical controls. Decreased distractor interference at high loads in participants with ASD contrasted attenuation of enhanced late, perceptual processes indexed by the N200 in neurotypical controls. Increased perceptual capacity and decreased distractor processing suggest enhanced bottom-up attention in participant with ASD and has a direct relationship to atypical sensory reactivity in ASD. Collectively, data describes intact top-down control, behaviorally and neurophysiologically, while demonstrating benefits of atypical sensory reactivity on bottom-up attention in people with ASD.