Children with autism have structural and functional abnormalities in the mesolimbic reward pathway, which contribute to social interaction impairments, according to a new study in Brain.
The researchers examined two independent cohorts, totalling 82 children aged 7-13 years with autism spectrum disorder matched against typically developing children, using high angular resolution diffusion-weighted imaging and functional MRI data.
They identified white matter tracts linking the nucleus accumbens and the ventral tegmental area, and provided reproducible evidence for structural aberrations in these tracts in children with autism.
Further, they showed that these structural aberrations are accompanied by aberrant functional interactions between the nucleus accumbens and ventral tegmental area in response to social stimuli.
“Crucially, we demonstrate that both structural and functional circuit aberrations in the mesolimbic reward pathway are related to parent-report measures of social interaction impairments in affected children,” the study authors said.
The findings provide fundamental insights into the neurobiological mechanisms underlying reduced social interest in humans.
"Human social cognition is complex," said senior author Vinod Menon, professor of psychiatry and behavioral sciences at Stanford University in the US. "We were surprised we could trace deficits in social skills to a very simple, almost primordial circuit."