Scientists from Stanford University detected differences in a region of the brain linked to the processing of social information
Children with autism spectrum disorders (ASD) often display atypical learning styles, however little is known about learning-related brain plasticity and its relationship to clinical phenotypic features. It is also common for them to show difficulties in identifying emotional signals.
Now, a work team from the Stanford University School of Medicine, USA, has detected that this condition for which it is sometimes difficult for them to understand the emotionality in the voices of other people is due to differences in the connections and function of a key social center in the brain.
The findings, published in Biological Psychiatry: Cognitive Neuroscience and Neuroimaging, offer an explanation for the neurological origin of a key social challenge in autism. They also provide clues as to the type of therapy that might help that situation.
“Children typically learn to assign certain sounds in people’s voices to particular emotions. If mom or dad isn’t happy, a young child will know it before they understand all the words,” said study co-senior author Daniel Abrams, an associate clinical professor of psychiatry and behavioral sciences at Stanford Medicine.
He further noted that “young children recognize slow, low-pitched speech as a sign of sadness. But children with autism have trouble relating vocal characteristics to emotions. Before this study, we didn’t know why the brains of people with autism have a barrier to identifying and recognizing these vocal signals.”
Clues for Social Interaction
In their study, the Stanford researchers noted that autism is a developmental disorder that affects 1 in 54 children and is characterized by problems with social communication, stereotyped behaviors, and restricted interests. Previous research on social communication in autism has focused primarily on how people with autism interpret facial expressions.
But vocal prosody, the technical name for emotional cues in voices, may be an even more important signal of how others are feeling, the researchers found.
”These are some of the most basic signs between parents and children, and between partners or adult couples. They help us decode the mental and emotional states of others and are crucial for successful social interactions,” said Vinod Menon, another of the paper’s lead authors.
There are two competing theories as to why people with autism have a hard time recognizing these signs. One theory, the sensory deficit model, holds that the auditory processing regions of the brain treat vocal sounds differently in autism. The idea was developed because many people with autism react differently than neurotypical people to non-speech sounds; for example, they may be sensitive to loud noises such as those produced by a vacuum cleaner.
The alternative theory, which focuses on social cognition, suggests that auditory processing of voices is normal in autism, but the social parts of the brain interpret the information differently than in neurotypical people. The new study, designed to pit these theories against each other, supports the second. For the study, the scientists recruited 22 children with autism and 21 typically developing children who served as controls.
The children, who ranged in age from 7 to 12, completed tasks to test their recognition of emotions in voices. For the voice recognition task, they listened to several recordings of two sentences: “a bag is in the room” and “my spoon is on the table”, both said with happy, sad or neutral intonation.
As in previous studies, children with autism were less able than those with normal development to identify emotions from the intonation of the recordings. Then, while receiving functional brain MRIs, the children listened to the recorded phrases several more times, as well as recordings of non-speech sounds, such as a dishwasher running. The researchers compared activity in different areas of the brain in the two groups of children.
“We found that most of the auditory parts of the brain respond to these voices like neurotypical children, and what was atypical in those with autism was the way this signal reaches a crucial social brain region. The region, the temporoparietal junction, is important to the ability to understand that other people have different thoughts and emotional states than one does. In children with autism, the auditory centers and the temporoparietal junction are highly connected compared to normally developing children. There is a sweet spot in the way the brain sends signals, and under- or over-connection between brain regions is problematic,” Abrams said.
The difference in brain connectivity between children with autism and those with typical development was more pronounced for sad voices than for happy ones, the researchers found. “Other research has suggested that decoding sad emotions is a particular deficit in autism. Being able to perceive sadness in others is important for effective social communication,” Menon reported.
The scientists also found that children who showed greater differences in temporoparietal junction activity, rather than connectivity between brain centers, had more difficulty with social interaction.
“For me, the most exciting aspect of our findings is that we could explain the severity of social communication difficulties in children with autism by looking at how less often they activated their social brain network while listening to emotional speech. This suggests that the temporoparietal junction could be a promising brain region to remedy social communication difficulties in children with autism,” said Simon Leipold, another of the paper’s lead author specialists.
The findings could point experts toward therapies that help children with autism develop social skills, as they provide a brain target that would likely be associated with effective treatment.
Other Stanford Medicine research has examined game-like methods to help children with autism learn to identify facial expressions. Scientists could try a similar method to teach children with autism to process vocal emotions and use fMRI to see if it changes the brain circuitry.
“Remedial circuitry at the temporoparietal junction could improve social and linguistic communication. I think it’s a very real possibility,” Menon suggested. The discoveries also provide opportunities to educate all children about neurodiversity, the concept that people with different types of brain wiring, including those on the autism spectrum, experience the world in different ways and all have valuable things to contribute.”
A critical way that children learn to identify the emotions of others is through interactions with friends, however, children with autism may have fewer opportunities for these experiences if typically developing children are hesitant to form friendships with others. they.
“If we are really going to improve communication with people with autism, everyone needs to learn. Parents might say to their neurotypical child, “That other kid may have trouble acknowledging how you’re feeling, but he really wants to know.” That additional knowledge can help keep people with autism in the conversation,” Abrams said.
Abrams shares lead authorship on the study with Simon Leipold, who was a postdoctoral fellow at Stanford Medicine when the research was conducted. Leipold is now a postdoctoral fellow at the Donders Institute for Brain, Cognition and Behavior at Radboud University in the Netherlands. The study’s senior authors are Vinod Menon, Rachael L., and Walter F. Nichols, professor and professor of psychiatry and behavioral sciences.