Children with autism spectrum disorder show atypical electroencephalographic response to processing contextual incongruencies
In the ERP literature, findings have also been reported on the P600 when it comes to language processing. This ERP component can be observed most commonly in the 500-900ms time frame, with a parietal morphology57. P600 was originally thought to be a component of manipulation of syntactic data57. However, it has been linked with conflict monitoring58.59.60. The P600 response is found in many syntactic violations, including phrase structure violations61, semantic violations within extended discourse contexts62. The P600 response is consistently linked to capturing differences in syntactically congruent versus incongruent structures (e.g.27,66.67). There has been some debate about whether P600 responses in these cases are specific to syntax processing, or if they are linked to more general domain processes such as learning, attention, or context updating. Fitz and Chang (70) proposed a model that presented P600 as a prediction error in the sequencing layer. Their studies showed that the recorded components of ERP could be the result learning processes that help in the adaption process to new inputs.
These studies also suggest that P600 is a process of integration in the understanding of the visual environment. Sitnikova and al.71 showed movie clips with real-world events that had two different endings, one congruent to the context and the other incongruent. They found that violations of the expected events elicited a P600 component. This led them to conclude the understanding of visual reality required two mechanisms, N400 and P600. The P600 latency and amplitude are also affected by differences in language processing among ASD individuals. In the study of linguistic violations, those with ASD showed longer reaction times72 as well as a more widespread distribution of P600 effects73. P600 variations are associated with increased attentional costs and compensatory strategies. There are few studies that attribute the P600 response to ASD individuals’ incongruency.
In light of the often mixed results found in ASD studies, it is crucial to identify paradigms that can be used to distinguish differences in neural responses to context language processing. Our study aims to investigate the brain processing of children with ASD in relation to difficulties in interpreting language in context. In order to achieve this, our study focused on the detection of incongruencies within context. We used a task that required integrating auditory and visual information to determine whether a given sentence is incongruent with the context or congruent (incongruent conditions). Incongruent conditions were divided into two categories: grammatically-correct sentences and sentences with semantic errors. The 2 x2 design consisted of images (context), accompanied by a verbal description (language) which could either be congruent or not. We compared the ERP wave amplitudes of the N400 and P600 components between children with ASD, and controls who were typically developing. We measured group differences as well as differences between two conditions in the groups. We hypothesized individuals in the typically-developing group would detect incongruencies, and in response present significantly higher N400 amplitudes and P600 amplitudes in the incongruent condition compared to congruent conditions. The ASD group was also expected to have difficulty detecting inconsistencies between context and description. We expected that when investigating group differences we would find significant differences between the amplitudes N400 and P600 of ERPs under incongruent conditions. The non-autistic groups had larger ERP amplitudes.
Source:
https://www.nature.com/articles/s41598-022-12475-z
