Abstract
INTRODUCTION: Motor difficulties are frequent in autistic children and associated with diverse social behavior, possibly due to atypical neural processing subserving internal action models. This systematic review synthesizes results from current functional magnetic resonance imaging (fMRI) research of brain activation during execution, imitation and observation of naturalistic actions in autistic children and adolescents (<18 years). METHODS: Peer-reviewed articles in English published between 2000 and 2025 reporting task-related fMRI in diagnosed autistic vs. typically developing youth (<18 years) were evaluated. Eight studies (with a total of 129 autistic and 128 typically developing participants) were identified, divided into action execution (n = 1), observation (n = 4), and imitation (n = 3). RESULTS: Between-group differences included reduced cerebellar activations for execution in autistic children; higher activity in left-lateralized motor processing regions for imitation; and lower activity in temporoparietal, posterior cingulate and anterior prefrontal cortex for observation. DISCUSSION: Findings suggest that atypical brain activation during action execution, observation and imitation in autistic youth is frequent and largely support the notion of aberrant formation and use of motor representations in autism development. Although, due to the limited number of studies, small samples, variability in fMRI pipelines, and task specific nature of the results, interpretations require caution and further investigations are warranted.