"Hyperscanning" Study Reveals Impaired Sense of Self in Autism

Scientists last week reported an exciting innovation for autism researchin a study that scanned the brains of people with autism during socialinteractions. The study, funded in part by Autism Speaks, revealed areduced brain signal in people with autism that might be related totheir sense of self. The study appeared as the cover article in thehigh-profile journal Neuron, and heralds a new tool for understandingwhy individuals with autism have difficulty in social interactions."It's the first time anyone's actually engaged kids with autism in asocial exchange as they're being scanned," said first author Pearl Chiu,Ph.D., of the Computational Psychiatry Unit (CPU) at Baylor College ofMedicine. While scanning people with autism using functional magneticresonance imaging (fMRI) is commonplace, this study goes further bymonitoring their brain activity while they interact with another person.In fact, both people's brains were scanned simultaneously, using amethod called "hyperscanning" which was pioneered by the senior authorof the study and director of the CPU, P. Read Montague, Ph.D.Hyperscanning allows scientists to "eavesdrop on both brains at once,"said Dr. Montague, providing essential data for understanding the neuralunderpinnings of social exchange.To study social interactions in the confined space of a fMRI scannerwhere it is crucial for the head to remain still, subjects in separatescanners played an interactive trust game while watching screens andusing toggle buttons to relay their responses to each other, in a setupreminiscent of online video gaming. This trust game involves exchangesof money between two players, and has been used to characterize andquantify reciprocal interactions between people. "It's designed to probesocial exchange, social interaction, reciprocity, and sensing andresponding to social signals," said Dr. Montague.The new study found that adolescent boys with high-functioning autismcould understand and play the game successfully, performing similarly toage- and IQ-matched controls. Even though their game playing was normal,however, their brain activity was not. Scanning during the task revealedunusually quiet activity in a portion of the cingulate cortex, a part ofthe brain thought to mediate social cognition. This occurred just afterthe autistic individual decided on the amount of money to give to hispartner in the other scanner. In contrast, control subjects displayedhigh activity in the same situation. This particular brain activity wastermed a "self response" because it occurred whenever a person made adecision of their own, but not when presented with the decision of theirpartner.The discrepancy between normal game playing and abnormal brain signalspoints to key differences in how the subjects with autism processed thesocial interaction. "It's almost as though they can mimic what needs tooccur in a social interaction, but the deeper attribution of thatinteraction to themselves is absent," said Dr. Chiu, who also pointedout that each subject had been in intensive behavioral therapy to learnappropriate social behaviors. The diminished "self responses" in theindividuals with autism resembled the decreased responses observed incontrol subjects when they play a computer that does not reciprocate asa human would, said Dr. Montague.The researchers speculate that the decreased self responses reflect animpaired sense of self in autism, which could lead to difficulties innavigating social situations. For example, making good guesses aboutanother person's intent is a key skill during a social interaction, andthis ability likely draws from awareness of one's own intentions.Consistent with this idea, the strength of the "self responses" in theindividuals with autism correlated with their symptom severity: thosewith the most reduced "self response" activity had the most severesymptoms in the social and communication domains.The brain circuitry that mediates social behavior is still a mystery,which is why Dr. Montague's technique is so important. The innovativecombination of game playing and hyperscanning can effectively probe thesocial difficulties that are some of the most defining features ofautism. Now that social interactions can be imaged inside the lab, thesepowerful techniques-with a willing cadre of volunteers with autism-canbegin to examine the brain mechanisms of social exchange, leading to abetter understanding of why people with autism struggle in socialsituations. The more we understand why individuals with autism havedifficulty in social interaction, the better we will be able to designinterventions that can help overcome this difficulty.-Michele Solis, Ph.D.