Is Autism Associated With Stronger or Weaker Brain Connections?

Jan 11 2018

Is Autism Associated With Stronger or Weaker Brain Connections?

The Finding:

In a new study that sheds light on a longstanding paradox in autism research, investigators showed how children and teens with autism spectrum disorder (ASD) can have both stronger and weaker brain connections than their typically developing peers. Resting-state functional magnetic resonance imaging (fMRI) revealed that while individuals with ASD have weaker brain connections compared to their peers overall (a measure known as absolute connectivity), they simultaneously exhibited stronger connections within the brain networks implicated in attention and social cognition compared to their other networks (a measure known as relative connectivity). Additionally, the more these brain connections differed from typical development, the more severe the child’s ASD symptoms seemed to be.

Why it matters:

The findings are the first step in understanding why previous autism research into functional connectivity — a field focused on the relationship between brain regions — seems to produce mixed results across different studies. According to Benjamin Yerys, PhD, a senior scientist and child psychologist the Center for Autism Research (CAR) at Children’s Hospital of Philadelphia, the results show that how we define and measure “functional connectivity” — such as the choice to use absolute or relative strength of the connection — plays an important part in observing whether children have stronger or weaker connections. These new insights into how the brain communicates differently in children and teens with ASD also have the potential to expand our understanding of how children with ASD interpret the world, including what social, sensory, or communication challenges they might face.

Who conducted the study:

Led by Dr. Yerys, the team included researchers from CAR, the department of Child and Adolescent Psychiatry and Behavioral Sciences, and the department of Pediatrics at CHOP, as well as investigators from the department of Psychiatry at the University of Pennsylvania’s Perelman School of Medicine, the departments of Bioengineering and Electrical and Systems Engineering at the University of Pennsylvania, and the department of Psychiatry at the University of North Carolina at Chapel Hill.

How they did it:

Dr. Yerys and his colleagues examined the strength of connections both within and across brain networks in 163 children and adolescents, 81 of whom have ASD. Using resting-state fMRI allowed the team to measure communication between two brain regions over time: The more synchronized the communication, the stronger the connection.

Quick thoughts:

“Studies on functional connectivity give us hints about what is different in the brain networks of children and teens with ASD, but we are still far away from using a brain scan to pick out the right treatment for the right child at the right time,” Dr. Yerys said. “Our goal is to find the best methods that tell us how to treat individuals. To achieve that goal, we will need careful research outlining the wide range of variability across children so we can identify when a child’s brain function or development is significantly off course.”

What’s next:

In a press release, Dr. Yerys said that he hopes the study will drive other investigators to examine both absolute and relative strength functional connectivity. The research is also part of a larger effort at CAR to discover how sensory and motor functions might influence social difficulties in children with ASD.

Where the study was published:

The study appeared in Molecular Autism.

Where to learn more:

Read the full study and related research from Dr. Yerys online, and a summary on CAR’s website.