Less flexibility in brain wiring of children with autism

A study shows that the brain wiring of children with autism is much less flexible than other children. This causes children with autism to have trouble in new situations.

When most children take on a task, various brain connections fire up. But scans showed less of this neuro-boosting activity in kids with autism, according to a small new study.

Moreover, children with more severe symptoms of autism displayed even less of this "brain flexibility," the researchers found.

"This reduced flexibility often causes difficulty when children with autism are faced with new situations," said study lead author Lucina Uddin, a neuroscientist and assistant professor of psychology at the University of Miami in Florida. "Knowing how the brain responds differently in these scenarios can help us to make transitions easier for these kids."

The finding -- published July 29 in Cerebral Cortex -- won't immediately lead to improvements in prevention, diagnosis or treatment of autism, which is estimated to affect one in 68 children in the United States. Still, it may provide more insight into the mysterious workings of the brain in autism.

People with autism have trouble interacting with others because they can't interpret many social signals that humans send to one another. They also engage in repetitive behaviors, such as obsessively focusing on one topic, or repeating the same action over and over.

"Based on our recent findings of overconnectivity in the brains of children with autism, I wanted to test the idea that a flexible brain is necessary for flexible behaviors," Uddin said.

In the new study, researchers performed brain scans on 34 children with autism and 34 typically developing children while at rest and while performing a task -- either solving math problems or distinguishing faces from one another. The idea was to include tasks that would -- and wouldn't -- significantly challenge kids with autism.

The kids with autism did as well as the others on the tasks. However, "across a set of brain connections known to be important for switching between different tasks, children with autism showed reduced 'brain flexibility' compared with typically developing peers," Uddin said.

The researchers also found a connection between the severity of restricted and repetitive behaviors and the degree of inflexibility.

In the big picture, "the findings may help researchers develop new therapies that target brain flexibility through strategies, tools and games that improve task-switching, for example," said study co-author Kaustubh Supekar, a science research associate with the department of psychiatry and behavioral sciences at Stanford University School of Medicine.

Jose Perez Velazquez, a senior scientist with Toronto's Hospital for Sick Children, cautioned that just because the brains of people with autism work differently doesn't mean that they work in a worse way. When it comes to behaviors, "which ones we want to label pathological or deviant is, many times, a matter of taste," said Velazquez, who wasn't involved in the study.

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Autism and sensory disorders affect different parts of the brain

A study shows that autism and sensory disorders affect distinctly different parts of a child's brain.

Although the vast majority of kids with autism have abnormal sensory behaviors, their brains are still wired very differently from children who have trouble processing sensory stimuli, researchers report.

Children with sensory processing disorders (SPD) can be overly sensitive to sound, sight and touch. They can also have poor motor skills and show a lack of concentration.

Complicating matters, some kids with SPD have more severe symptoms than others. Some have trouble tolerating loud noises, like a vacuum. Others can't hold a pencil or control their emotions. Symptoms can also vary from one day to the next. This had led to a debate about whether SPD should be considered a separate disorder, the researchers pointed out.

These kids "often don't get supportive services at school or in the community because SPD is not yet a recognized condition," study corresponding author Dr. Elysa Marco, a cognitive and behavioral child neurologist at Benioff Children's Hospital San Francisco at the University of California, San Francisco (UCSF), said in a university news release. "We are starting to catch up with what parents already knew; sensory challenges are real and can be measured both in the lab and the real world."

"With more than 1 percent of children in the United States diagnosed with an autism spectrum disorder, and reports of 5 to 16 percent of children having sensory processing difficulties, it's essential we define the neural underpinnings of these conditions, and identify the areas they overlap and where they are very distinct," study senior author Dr. Pratik Mukherjee, a professor of radiology and biomedical imaging and bioengineering at UCSF, said in a university news release.

In conducting the study, published online July 30 in the journal PLOS ONE, the researchers compared the brains of 16 boys with SPD and 15 boys with autism. All of the boys were between the ages of 8 and 12. These patients were compared to 23 boys who were developing normally.

Using an advanced form of MRI, the researchers were able to examine white matter, the "wiring" that links different areas of the brain.

The boys with SPD and autism had reduced connectivity in certain areas of the brain involved in basic sensory information. However, only the boys with autism had impairment in specific parts of the brain essential for social-emotional processing.

"One of the classic features of autism is decreased eye-to-eye gaze, and the decreased ability to read facial emotions," noted Marco. "The impairment in this specific brain connectivity not only differentiates the autism group from the SPD group but reflects the difficulties patients with autism have in the real world. In our work, the more these regions are disconnected, the more challenge they are having with social skills."

Meanwhile, children with SPD had less connectivity in the tracts of the brain involved in sensory processing.

"One of the most striking new findings is that the children with SPD show even greater brain disconnection than the kids with a full autism diagnosis in some sensory-based tracts," noted Marco. "If we can start by measuring a child's brain connectivity and seeing how it is playing out in a child's functional ability, we can then use that measure as a metric for success in our interventions and see if the connectivities are changing based on our clinical interventions."

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Brain differences in those with Autism: Think Local Not Global

A new study shows that a person with autism's brain is wired differently than those without autism, and this finding may help explain some of the typical symptoms of autism. 

Increased connectivity may favor local connections over global. - JR

The way the gray matter in the brain is wired appears to be different in people with autism, new research shows.

Specifically, those with the disorder are more likely to have enhanced connections in the brain that are associated with common autism symptoms, such as narrow interests and repetitive behaviors, the scientists reported.

"Our study [and others] reliably and repeatedly demonstrate that the brain in autism is built and functions differently, which explains a variety of autistic symptoms," said study author Christine Ecker, a lecturer in neuroimaging at King's College London.

"From neuropsychology, we also know that people with autism often have a preference for processing [fine details] over global features (the ability to integrate piecemeal information into a coherent whole)," she said. "Our findings may therefore represent a neuroanatomical correlate of these behaviors, although a direct causal link remains to be established."

Results of the study were published online July 22 in the Proceedings of the National Academy of Sciences.

Autism spectrum disorders are a group of neurodevelopmental disorders, common symptoms of which include impaired social communication, social reciprocity and repetitive behaviors, according to background information included in the study. Experts believe that differences in the brain account for these behaviors, but the exact changes that might occur in someone with autism aren't yet clear, according to the study.

The current study looked at 34 adult males with autism and 34 males without autism to serve as the control group. All of the study volunteers underwent MRI.

The researchers found that there were significant differences in the length of the connections between regions of the brain when they compared people with autism to those without. The minimum length of these connections in the cortical gray matter was dubbed "wiring costs" by the researchers. These wiring costs were significantly reduced in people with autism, meaning the lengths of their connections were shorter.

"These differences are predominantly observed in brain regions that we know are anatomically different in autism, and that are underlying autistic symptoms and traits," Ecker said. "We think that such differences in neuronal wiring may lead to locally over-connected networks in the brains of [patients with autism spectrum disorders] that could explain some autistic symptoms, such as repetitive behaviors."

One expert said the findings help define the biological basis of autism more clearly.

"We've known that there is a history of wiring differences that appear in individuals with autism. What's novel is that they used structural imaging to assess whether neurons are connected in the same way structurally," said Daniel Smith, senior director of discovery neuroscience at Autism Speaks.

"Gray matter connections are referred to as microcircuits, and they're everywhere," Smith said. "They're very important in the cerebral cortex, and the highest levels of thinking occur in the cerebral cortical regions of the brain."

"This study is another component in building our knowledge base," he added. "It's a step toward better understanding of what's happening in the brain and, ultimately, that will help lead to new treatments. But this study won't lead to an immediate impact on treatment."

Dr. Andrew Adesman, chief of developmental and behavioral pediatrics at the Steven and Alexandra Cohen Children's Medical Center in New Hyde Park, N.Y., agreed that this study won't lead to any immediate changes in the field.

"Unfortunately, despite the many advances in our ability to study the brain and identify a range of structural and functional differences associated with autism, we are still left with more questions than answers," Adesman said.

"[But] studies such as this bring us one step closer to understanding the neurobiological underpinnings of the mysterious and enigmatic condition known as autism spectrum disorder," he said.

Ecker said she hopes to conduct a study that follows young people as their brains are developing to see how the connections in the brain behave over time in people with autism.

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