Background

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by impaired social communication and repetitive behaviours. Studies have shown that ASD is associated with altered connectivity in the brain and is therefore not a local brain disorder but a disorder involving functional networks. In this study, we extensively investigated changes in brain connectivity across multiple networks in patients with ASD using a network metric called functional connectivity overlap ratio (FCOR). In addition, we also examined if connectors hubs, brain regions with connections to multiple functional networks, are involved in ASD.

Methods

Resting-state functional MRI data from 125 patients with ASD and 125 age- and sex-matched healthy controls (HC), obtained from the publicly available data set called SRPBS, were used in the analysis. FCOR maps were generated for each subject and differences in FCOR values between ASD and HC were identified using two-sample t-tests.

Results and Discussion

The right executive control network had the highest number of voxels with significantly lower FCOR values in patients compared to controls, followed by the salience (posterior and anterior), basal ganglia, and precuneus networks. On the other hand, the salience network had the highest number of voxels with significantly higher FCOR values in patients, followed by the basal ganglia network, and others. Connector hub regions showing impaired connections with multiple networks included the insula, thalamus, caudate nucleus, and putamen. These findings suggest that the connectivity of the salience and executive control networks is significantly impaired in ASD. The former is thought to regulate attention between external and internal stimuli, whereas the latter is associated with executive function and social cognition. Thus, their impairment may lead to a worsening of sensory experience in ASD, resulting in the dysregulation of social cognition typically observed in this disorder.

Conclusion

The connectivity of the core neurocognitive networks (salience, executive control, default mode) is impaired in ASD, potentially driven by the disconnection of these networks’ connector hub regions.