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Introduction: Impaired motor functioning is a common characteristic of individuals with autism spectrum condition (ASC). Despite high prevalence, longstanding recognition, and association with core symptom severity, the neural underpinnings of motor difficulties remain inadequately investigated, particularly regarding complex and object-directed movements.

Patients and Methods: In this functional magnetic resonance imaging (fMRI) study, we investigated ASC(n = 21; M = 26.0 years) and neurotypical([NT]; n = 28; M = 27.5 years) adults while planning to execute, and while executing, a sequential manual task with demands on object rotation. The analyses were confined to a mask comprising five motor-parietal and nine cerebellar regions of interest in the hemisphere contralateral to the executing hand.

Results: A conjunction analysis of the respective planning and execution events revealed significant shared activation in the inferior parietal lobe (IPL) for the ASC group, whereas the NT group showed more sizeable overlapping activation in two posterior cerebellar regions and IPL. When comparing the planning and execution events separately betweenthe groups, the ASC group exhibited lower activation of IPL and precentral gyrus during planning, and higher activation of posterior cerebellum during execution, compared to the NT group.

Conclusion: These novel findings indicate differential brain activation between ASC and NT adults during planning and execution of complex sequential manual actions, potentially reflecting processing differences in motor automatization and integration of prior experience. These results contribute to advancing the understanding of atypical motor performance in ASC.