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Deficits in reward pathway impact social skills in childhood autism
Structural and functional circuit deficits in the mesolimbic reward pathway contributed to measures of social interaction impairments in children with autism, study findings showed.
“Impairments in social communication are a hallmark of autism. These impairments are a major impediment to effective functioning in individuals with autism, yet the brain basis of social impairments is unknown,” Kaustubh Supekar, PhD, from the department of psychiatry and behavioral sciences, Stanford University, told Healio Psychaitry. “Uncovering the neurobiological mechanisms underlying this core symptom of the disorder is important not only for a more precise understanding of the neurobiology of autism but also for developing more accurate biomarkers and targeted treatments.”
Researchers examined whether structural and functional integrity of the mesolimbic reward pathway, which regulates and supports appetitive behaviors via dopaminergic signaling, was abnormal in ASD and whether these discrepancies contributed to social interaction impairments.
Using high angular resolution diffusion-weighted imaging and functional MRI data, they assessed structural and functional brain connectivity of the reward pathway in two independent cohorts of children aged 7 to 13 years as they viewed social or nonsocial images. They compared 24 children with autism and 24 matched typically developing children in the primary cohort, and 17 children with autism vs. 17 typically developing children in the replication cohort.
The results revealed that deficits in the mesolimbic reward pathway in children with ASD and the degree of abnormality in this pathway predicted the degree of social impairment, according to a press release.
In children with autism, the density of nerve fiber tracts in the reward pathway was lower than in typically developing children; however, there were no differences between those with and without autism when Supekar and colleagues examined an emotion-related brain pathway as a control, the press release said. The lower density of nerve fiber tracts found in youth with ASD was associated with greater social impairment. These findings were the same in the replication cohort. In addition, participants with autism had weaker functional connections in the reward pathway compared with typically developing children, and the degree of functional deficit correlated to social impairment.
“Our findings suggest that targeted treatments focusing on reward and motivation may alleviate social impairments in affected children,” Supekar told Healio Psychaitry.
“We were surprised we could trace deficits in social skills to a very simple, almost primordial circuit. Social interaction is usually inherently rewarding. If it's not rewarding enough to a child with autism, that could have cascading effects on other brain systems," Vinod Menon, MD, from Stanford University, said in the press release. "Our findings suggest that this is a brain system that should be targeted early in clinical treatments." – by Savannah Demko
Disclosure: Healio Psychiatry was unable to confirm any relevant financial disclosures at the time of publication.