This collection contains the EEG and behavioural data relating to the article by Toffoli et al. published in the journal, 'Cortex': 'Global motion evoked potentials in autistic and dyslexic children: a cross-syndrome approach'. Atypicalities in psychophysical thresholds for global motion processing have been reported in many neurodevelopmental conditions, including autism and dyslexia. Cross-syndrome comparisons of neural dynamics may help determine whether altered motion processing is a general marker of atypical development or condition-specific. Here, we assessed group differences in N2 peak amplitude (previously proposed as a marker of motion-specific processing) in typically developing (n = 57), autistic (n = 29) and dyslexic children (n = 44) aged 6 to 14 years, in two global motion tasks. High-density EEG data were collected while children judged the direction of global motion stimuli as quickly and accurately as possible, following a period of random motion. Using a data-driven component decomposition technique, we identified a reliable component that was maximal over occipital electrodes and had an N2-like peak at ~160 ms. We found no group differences in N2 peak amplitude, in either task. However, for both autistic and dyslexic children, there was evidence of atypicalities in later stages of processing that require follow up in future research. Our results suggest that early sensory encoding of motion information is unimpaired in dyslexic and autistic children. Group differences in later processing stages could reflect sustained global motion responses, decision-making, metacognitive processes and/or response generation, which may also distinguish between autistic and dyslexic individuals.Autism affects social functioning and encompasses sensory symptoms such as aversion to sounds or fluorescent lights. It is not known why sensory symptoms occur. Previous research has overlooked the dynamic process leading to sensory responses, so we do not know the point at which differences arise. For example, whether a heightened sensory response in autism is due to taking in sensory information too quickly or if it is an aversive response triggered at a lower level of sensory stimulation. I will investigate the nature and source of sensory symptoms in autism by studying which stages of sensory processing are different, how differences relate to brain activity and how sensory processing affects movements in people with autism. I will also investigate how processing differences relate to sensory symptoms and whether additional difficulties, such as motor problems or attention difficulties, affect sensory processing in people with autism. I will measure electrical activity at the scalp while children with and without autism respond to sensory information. I will combine behavioural and brain activity measures using mathematical models. Parents will complete questionnaires about their child‘s sensory processing and other difficulties. The findings from this study will help to design future interventions and support for people with autism who experience sensory symptoms.

The sample included 57 typically developing children, 29 children with an autism diagnosis and 44 children with a dyslexia diagnosis, aged 6 to 14 years (see Table 1 for demographic information). Participants were recruited from local schools, community contacts and invitations to families who participated in previous studies, as part of larger studies assessing perceptual decision-making in autism and dyslexia using Bayesian models (https://osf.io/znyw2 and https://osf.io/enkwm). These larger studies determined the sample of participants tested. Two experimental tasks were presented on a computer using MATLAB: a direction integration task and a motion coherence task. In both tasks, children were asked to judge the direction of motion as quickly and accurately as possible. EEG data were collected with a 128-electrode Hydrocel Geodesic Sensor Net connected to Net Amps 300 (Electrical Geodesics Inc., OR, USA), using NetStation 4.5 software. A photodiode attached to the monitor independently checked the timing of stimulus presentation. Children made their responses using a Cedrus RB-540 response box (Cedrus, CA, USA). For further details, please see the published manuscript.