Autism spectrum disorder (ASD) affects social interaction and communication.
A new brain imaging study provides insights into how disruptions in the brain’s social networks may relate to core autism symptoms.
The research identifies specific brain regions and circuits that differ in children with ASD compared to typically developing peers.
Key Facts:
- Children with ASD showed altered connectivity between brain areas linked to social processing and regions involved in movement control and sensation.
- Differences in connectivity were associated with more severe social and communication deficits.
- Brain network organization also differed in ASD, with patterns suggesting reduced information flow between neighboring areas.
- Findings point to a link between social brain disruptions and repetitive behaviors in ASD.
- The regions identified could be targets for brain stimulation treatments to improve social abilities in ASD.
Source: Brain Sciences (2023, 13, 280.)
Examining the Social Brain in Autism
Autism is a neurodevelopmental condition characterized by challenges with social communication and interaction as well as restrictive and repetitive behaviors.
Researchers have been working to understand how altered brain connectivity may contribute to the core features of autism.
In this new study, scientists used brain imaging to take a closer look at the brain’s “social networks” in children with ASD.
They focused on examining the functional connections between brain regions known to be important for social processing.
The team compared functional MRI scans from 51 boys with ASD and 54 matched controls. The children were ages 6-12 years old.
During the brain scans, the participants were not performing any particular task. This allowed the researchers to map out the brain’s intrinsic functional connections while “at rest.”
Brain Imaging Reveals Disrupted Social Circuits in ASD
The brain imaging analyses revealed reduced connectivity between key social processing regions and multiple other parts of the brain in children with ASD.
Specifically, the researchers found weakened links between areas involved in social functions and regions that control movement and process body sensations, including the precentral gyrus, postcentral gyrus, and paracentral lobule.
Connections between social regions and areas involved in motor planning and coordination (supplementary motor cortex) were also diminished.
The same was true for links with the cingulate gyrus, which is part of the limbic system and relevant for attention and emotions.
Interestingly, many of the areas showing reduced connectivity were located in the left hemisphere of the brain. According to the authors, this suggests the left side may be more affected in terms of social brain disruptions in ASD.
Clinical Correlations – Linking Brain Patterns to Autism Symptoms
Not only were connectivity differences apparent at a group level, but the degree of social network disruption also related to autism symptom severity in individual children.
The researchers found that weaker connectivity between social regions and other parts of the brain correlated with more social-communication challenges as measured by standardized autism diagnostic tests.
Children with the lowest functional connectivity had the most severe social impairment and communication difficulties.
The data also revealed an association between social network alterations and repetitive behaviors. Children with the greatest disruptions in connectivity had higher scores for repetitive and stereotyped mannerisms.
This suggests a link between social brain abnormalities and core autism symptoms spanning both the social and behavioral domains.
Differences in Network Organization
In addition to examining connections between distinct brain areas, the researchers also investigated properties of the networks as a whole.
They found that networks in children with ASD showed reduced “clustering” – a measure of how interconnected each brain region is with its immediate neighbors. This suggests that local information processing may be disrupted.
The children with autism also exhibited increased “betweenness centrality” for many brain areas. This metric indicates how often a region acts as a bridge along the shortest path between two other nodes.
Higher betweenness centrality points to potential compensation in ASD as the brain relies more heavily on certain hubs with widespread connections across the network.
Overall, the organizational findings provide further evidence for atypical brain network functioning in ASD and align with the concept of local overconnectivity combined with long-range underconnectivity.
Targeting the Social Brain for Autism Therapies
According to the researchers, the social brain regions and circuits identified in this study could be promising targets for treatments aimed at improving social skills in ASD.
One possibility is using non-invasive brain stimulation, such as transcranial direct current stimulation (tDCS). The approach involves delivering a mild electrical current to the brain in order to modulate neural activity and connectivity.
The team suggests tDCS could potentially enhance connections between social processing areas and regions found to be underconnected in ASD, such as the sensory-motor cortices.
Toning down activity in overconnected areas through stimulation may also be helpful.
They propose testing tDCS of social brain targets as an avenue for improving social abilities in future studies.
The findings will need to be replicated in larger samples. However, the work takes an important step toward unraveling autism’s complex neural underpinnings and points to brain mechanisms that may be therapeutically targeted.
Understanding the social difficulties that are central to ASD requires studying how the brain’s networks enable social cognition and social skills.
Though much remains unknown, research efforts like this one are steadily piecing together the neurobiological picture in autism.
References
- Study: Social Brain Network of Children with Autism Spectrum Disorder: Characterization of Functional Connectivity and Potential Association with Stereotyped Behavior
- Authors: Yonglu Wang et al. (2023)
