It's long been observed that many kids with autism have a hard time communicating and socializing with others. Now a new study using MRI scans provides some clues as to why.
Thanks to a weaker connection between the brain's language and reward centers, the human voice may provide little to no pleasure at all to kids with autism.
As they report this week in the Proceedings of the National Academy of Sciences, researchers were able to spot "underconnectivity" using functional MRI, which tracks blood flow to look for brain activity.
Researchers scanned the brains of 20 children (average age: 10) with so-called "high-functioning autism" -- normal IQs but trouble hearing emotion in voices -- and 19 kids without autism but in the same age and IQ range. Not only did they find that those with autism exhibited weaker connections between the part of the brain that responds to the human voice and two regions associated with reward, but there was also a weaker link between the brain's voice processors and the amygdala, which involves emotion -- including the ability to perceive emotion in others.
"This is an elegant approach to using neuroimaging to better understand [autism]," Andrew Adesman of the Steven and Alexandra Cohen Children's Medical Center of New York, who is not associated with this study, said in a news release. "The natural next step is to try to replicate these findings in further studies, and to expand the research to include younger kids."
It's still unclear which came first -- the weaker brain connections or the lack of use of those connections due to some other neurological deficiency. Either way, these weak links suggest not only difficulty processing emotion in others' voices, but perhaps difficulty getting any pleasure out of voices at all.
"When we speak, we don't only convey information, we convey emotion and social cues," Daniel Abrams, who led the study out of Stanford, said in a news release. And of the theories as to why kids with autism may have a harder time reading those cues -- one is that the brain has some sort of sound processing deficit, another is that these social cues don't register with the brain's reward system in the same way -- this new work certainly leds credence to the latter.
Of course, the study is small and the findings preliminary, not to mention very specific; autism is a spectrum disorder that affects a wide range of people differently. These brain connectivity patterns may look very different in kids who appear at different points on the spectrum than the high-functioning ones studied.
Still, it's hard not to feel a little sympathy for these kids in the study who have a hard time reading social cues. Who'd want to sit around listening to people talk if those voices bring no pleasure?