Hyperscanning of Interpersonal Trust in Autism

Lay Summary

Imaging Interpersonal Trust in Autism

Baylor researchers will use a new imaging technology they have developed to  image simultaneously the brains of highly functioning individuals with autism engaged in social interactions.  This is the first study of its kind and may provide insight into why people with autism are unable to form trust relationships associated with normal social bonds.  Autism Speaks will contribute $90,000 for this project.

People with autism lack the capacity to understand and respond to social signals, making it difficult for them to engage and communicate effectively.  The researchers hypothesize that people with autism are not able to engage in effective social interactions because they lack the ability to interpret social signals and predict the expected actions of others.  Their hypothesis is based on initial findings from a new imaging technology they developed, called “hyperscan fMRI” (h-fMRI). This technique allows simultaneous functional imaging of brain activity in interacting individuals.

The Baylor group first tested h-fMRI in healthy volunteers who participated in a two-person “trust” game.  Using h-fMRI, the Baylor researchers visualized brain activity as participants developed trust and as they built models of one another through repeated interactions.  Results showed that a response pattern develops in a specific area of the brain when individuals decide to invest trust. A response also develops in a separate area of the brain when participants view their partners’ decisions to trust them.

In contrast, in a pilot study of seven males with a highly functional form of autism, researchers found that their brains associated their actions and their game partners’ actions as though both were the actions of someone else.  Now, the Baylor researchers will study people with autism paired with healthy partners and pairs in which both partners are healthy.  The Baylor group will determine whether people with autism lack the ability to develop trust in another, whether this “trust” response is present but weak, or whether this response is affected by something that was not captured in the pilot data.  The researchers also will determine whether people with autism lack the ability to model their partner’s responses.  They hypothesize that people with autism lack this modeling capacity and that this absence is the immediate cause of their incapacity to engage in effective social interactions.

Significance: This approach holds the potential for fundamentally advancing the study of autism by identifying impairment in a brain function required for social interaction.

Abstract

Hyperscanning of Interpersonal Trust in Autism

Our laboratory has recently developed a technology, called hyperscan-fMRI, that permits the simultaneous functional magnetic resonance imaging (fMRI) of interacting human subjects while they carry out simple forms of interactive social exchanges. Using this technology, we have generated a large database of normal human brain responses related to social signaling. The first new brain response appears in the caudate nucleus and correlates with the formation of each subject's model of their partner's likely next move. The second appears as a series of mapped responses across the anterior-posterior axis of the cingulated cortex. These responses are best described as a social agency map, a systematic spatial variation in fMRI signals that indicate the social agent ("self" or "other") responsible for the data currently being presented to both brains.

Inspired by these results with healthy participants, we have now carried out pilot h-fMRI trust games with high-functioning males with autism (n=7) and found that their cingulated cortex expresses only "other" responses with the "self" responses completely absent. This remarkable deficit in brain response in this special group may represent an important phenotype with which other features of autism spectrum disorders may correlate. This is the first time that brain responses of individuals with autism have been measured during an active social exchange. Using hyperscan-fMRI, this project seeks to substantiate (or not) the pilot findings and evaluate the hypothesis that the absent "self" response in autistic subject may be on proximate cause of their insensitivity to social signals from other humans.