Topographical differences during motion processing in autistic and dyslexic children

Atypical motion processing has been reported in multiple developmental conditions, including autism and dyslexia, and taken as support for a general developmental vulnerability in the dorsal stream. Yet by uncovering dynamically unfolding processes, electroencephalography can determine the extent to which motion processing signatures are shared or distinct across different developmental conditions. Here we used pre-registered topographical analyses across the whole high-density electrode array to determine, for the first time, whether autistic and dyslexic children activate the same or distinct brain pathways as typically developing children, when completing two motion processing tasks. Participants were 29 autistic, 44 dyslexic and 57 typically developing children aged 6 to 14 years. Group differences in overall brain response strength were found in both tasks. Topographical activity differed in both autistic and dyslexic children compared to typically developing children (but not between autistic and dyslexic children) in a motion coherence task between 456 - 560 ms. However, group differences in a direction integration task (with no incoherent motion) depended on stimulus difficulty and time window (434 - 500 ms and 538 - 638 ms), with different patterns of divergence from typical development in autism and dyslexia. These results suggest that there are differences in the brain networks used to accomplish motion processing tasks in both autistic and dyslexic children, and demonstrate the utility of a topographical approach for detecting group differences in neural mechanisms, which can be missed by univariate approaches. Key pointsO_LIWe use an electrical neuroimaging approach to provide new insights into the neural mechanisms of motion processing in autism and dyslexia C_LIO_LIAutistic and dyslexic children both differed from typically developing children in the strength and topography of their brain responses. C_LIO_LIMotion processing activates atypical brain networks in both autistic and dyslexic children. C_LI