Autism is a mysterious developmental disease. It often leaves complex abilities intact while impairing seemingly elementary ones.
Here's an example: It's well documented that autistic children often have difficulty correctly using pronouns. Sometimes they refer to themselves as "you" instead of "I."
A new brain imaging study published in the journal "Brain" by scientists at Carnegie Mellon University provides an explanation as to why.
Marcel Just, Akiko Mizuno and their collaborators at CMU's Center for Cognitive Brain Imaging (CCBI) found that errors in choosing a self-referring pronoun reflect a disordered neural representation of the self.
It's a function processed by at least two brain areas — one frontal and one posterior.
"The psychology of self — the thought of one's own identity — is especially important in social interaction, a facet of behavior that is usually disrupted in autism," said Just.
He is a leading cognitive neuroscientist and the D.O. Hebb Professor of Psychology at CMU who directs the CCBI.
"Most children don't need to receive any instruction in which pronoun to use. It just comes naturally, unless a child has autism," Just said.
Using functional magnetic resonance imaging (fMRI), the research team compared the brain activation and synchronization patterns in young adults with high-functioning autism with control participants during a language task that required rapid pronoun comprehension.
The results revealed a significantly diminished synchronization in autism between a frontal area and a posterior area during pronoun use in the autism group.
The participants with autism also were slower and less accurate in their behavioral processing of the pronouns.
"Shifting from one pronoun to another, depending on who the speaker is, constitutes a challenge not just for children with autism but also for adults with high-functioning autism, particularly when referring to one's self," Just said.
"The functional collaboration of two brain areas may play a critical role for perspective shifting by supporting an attention shift between oneself and others."
Just added, "Pronoun reversals also characterize an atypical understanding of the social world in autism. The ability to flexibly shift viewpoints is vital to social communication, so the autistic impairment affects not just language but social communication."
"This new understanding of what causes pronoun confusion in autism helps make sense of the larger problems of autism as well as the idiosyncrasies," Just said. "Moreover, it points to new types of therapies that may help rehab the white matter in autism."
In addition to Just and Mizuno, a psychology doctoral candidate and first author of the study, the research team included CMU's Yanni Liu, a postdoctoral associate, and Timothy A. Keller, a senior research psychologist; Duquesne University's Diane L. Williams, an assistant professor of speech-language pathology; and the University of Pittsburgh School of Medicine's Nancy J. Minshew, a professor of psychiatry and neurology.
This research was funded by the National Institute of Child Health and Human Development and the Autism Speaks Foundation.
To read a preprint of the article that will appear in "Brain," visit http://www.ccbi.cmu.edu/publications.htm.