| Sumario: | Background: In addition to their more clinically evident abnormalities of social cognition, people with autism spectrum conditions (ASC) manifest perturbations of attention and sensory perception which may offer insights into the underlying neural abnormalities. Similar autistic traits in ASC relatives without a diagnosis suggest a continuity between clinically affected and unaffected family members. Methods: We applied fMRI in the context of a non-social task of visual attention order to determined whether this continuity persists at the level of brain physiology. Results: Both boys with ASC and clinically unaffected brothers of people with ASC were impaired at a visual divided-attention tasks demanding conjunction of attributes from rapidly and simultaneously presented, spatially disjoint stimuli and suppression of spatially intervening distractors. In addition, both groups in comparison to control manifested atypical fronto-cerebellar activation as a function of distractors congruence, and the degree of this frontal a typically correlated with psychometric measures of autistic traits in ASC and sibs. Despite these resemblances between the ASC and sib groups, an exploratory, hypothesis-generating analysis of correlations across brain regions revealed a decrease in overall functional correlation only in the ASC group and not in the sibs.Conclusions: These results establish a neurophysiological correlate of familial susceptibility to ASC, and suggest that whilst abnormal patterns of functional correlation across a wider array of brain regions may relate more closely to autism's determinants.
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