Dyslexic readers have disrupted network connections in the brain

August 28, 2014

Dyslexia, the most commonly diagnosed learning disability in the United States, is a neurological reading disability that occurs when the regions of the brain that process written language don't function normally.

The use of non-invasive functional neuroimaging tools has helped characterize how brain activity is disrupted in . However, most prior work has focused on only a small number of brain regions, leaving a gap in our understanding of how multiple brain regions communicate with one another through networks, called , in persons with dyslexia.

This led neuroscience PhD student Emily Finn and her colleagues at the Yale University School of Medicine to conduct a whole-brain functional connectivity analysis of dyslexia using functional magnetic resonance imaging (fMRI). They report their findings in the current issue of Biological Psychiatry.

"In this study, we compared fMRI scans from a large number of both children and young adults with dyslexia to scans of typical readers in the same age groups. Rather than activity in isolated brain regions, we looked at functional connectivity, or coordinated fluctuations between pairs of brain regions over time," explained Finn.

In total, they recruited and scanned 75 children and 104 adults. Finn and her colleagues then compared the whole-brain connectivity profiles of the dyslexic readers to the non-impaired readers, which revealed widespread differences.

Dyslexic readers showed decreased connectivity within the visual pathway as well as between visual and prefrontal regions, increased right-hemisphere connectivity, reduced connectivity in the visual word-form area, and persistent connectivity to anterior language regions around the inferior frontal gyrus. This altered connectivity profile is consistent with dyslexia-related reading difficulties.

Dr. John Krystal, Editor of Biological Psychiatry, said, "This study elegantly illustrates the value of functional imaging to map circuits underlying problems with cognition and perception, in this case, dyslexia."

"As far as we know, this is one of the first studies of dyslexia to examine differences in functional connectivity across the whole brain, shedding light on the brain networks that crucially support the complex task of reading," added Finn. "Compared to typical readers, dyslexic readers had weaker connections between areas that process visual information and areas that control attention, suggesting that individuals with dyslexia are less able to focus on printed words."

Additionally, young-adult maintained high connectivity to involved in phonology, suggesting that they continue to rely on effortful "sounding out" strategies into adulthood rather than transitioning to more automatic, visual-based strategies for word recognition.

A better understanding of brain organization in dyslexia could potentially lead to better interventions to help struggling readers.

Explore further: In dyslexia, less brain tissue not to blame for reading difficulties

More information: The article is "Disruption of Functional Networks in Dyslexia: A Whole-Brain, Data-Driven Analysis of Connectivity" by Emily S. Finn, Xilin Shen, John M. Holahan, Dustin Scheinost, Cheryl Lacadie, Xenophon Papademetris, Sally E. Shaywitz, Bennett A. Shaywitz, and R. Todd Constable (DOI: 10.1016/j.biopsych.2013.08.031). The article appears in Biological Psychiatry, Volume 76, Issue 5 (September 1, 2014)

Related Stories

In dyslexia, less brain tissue not to blame for reading difficulties

January 14, 2014
In people with dyslexia, less gray matter in the brain has been linked to reading disabilities, but now new evidence suggests this is a consequence of poorer reading experiences and not the root cause of the disorder.

Understanding 'attention deficit' in dyslexics could help improve reading

July 3, 2014
(Medical Xpress)—A new study from researchers in our Department of Psychology has revealed that understanding attention deficits in adults with dyslexia may help develop new techniques for reading and writing.

Hear Jane read: Researcher gives new meaning to semantics

July 15, 2014
For years a key way of diagnosing dyslexia has been how well a person reads aloud. Similarly, the reading skills of adult readers also have been assessed by having them read words aloud. "The idea is that the more you read ...

Brain imaging study eliminates differences in visual function as a cause of dyslexia

June 6, 2013
A new brain imaging study of dyslexia shows that differences in the visual system do not cause the disorder, but instead are likely a consequence. The findings, published today in the journal Neuron, provide important insights ...

Dyslexia may be due to faulty brain wiring, study says (Update)

December 5, 2013
A roadblock in the brain makes reading difficult for people with dyslexia, a new study suggested Thursday, contradicting long-held opinion.

Recommended for you

A walk at the mall or the park? New study shows, for moms and daughters, a walk in the park is best

November 17, 2017
Spending time together with family may help strengthen the family bond, but new research from the University of Illinois shows that specifically spending time outside in nature—even just a 20-minute walk—together can ...

When male voles drink alcohol, but their partner doesn't, their relationship suffers

November 17, 2017
A study of the effect of alcohol on long-term relationships finds that when a male prairie vole has access to alcohol, but his female partner doesn't, the relationship suffers - similar to what has been observed in human ...

Risk of distracted driving predicted by age, gender, personality and driving frequency

November 17, 2017
New research identifies age, gender, personality and how often people drive as potential risk factors for becoming distracted while driving. Young men, extroverted or neurotic people, and people who drive more often were ...

Spanking linked to increase in children's behavior problems

November 16, 2017
Children who have been spanked by their parents by age 5 show an increase in behavior problems at age 6 and age 8 relative to children who have never been spanked, according to new findings in Psychological Science, a journal ...

Generous people give in a heartbeat—new study

November 15, 2017
Altruistic people are said to be "kind hearted" - and new research published in the journal Scientific Reports shows that generous people really are more in touch with their own hearts.

Teenage depression linked to father's depression

November 15, 2017
Adolescents whose fathers have depressive symptoms are more likely to experience symptoms of depression themselves, finds a new study led by UCL researchers.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.