Summary: New neuroimaging research shows that how well sensory-specific brain regions connect functionally as a network during childhood predicts later reading proficiency.
Source: University at Buffalo
Reading a simple sentence is more than recognition of symbols — it requires multiple brain regions to cooperate, transforming visual letters into the sounds they represent.
Researchers describe the set of brain areas that map letters to sounds (phonemes) as the “reading network.” A recent longitudinal neuroimaging study from the University at Buffalo finds that the degree to which these sensory-specific regions operate together functionally — not only through hard-wired anatomy but via coordinated activity — predicts a child’s reading development.
The study shows a developmental shift from segregated processing toward greater network integration. In other words, as children become more skilled readers, visual and auditory regions that once operated independently begin to function more cohesively. These changes in functional connectivity within the reading network are associated with improvements in decoding and phonological skills. According to Chris McNorgan, assistant professor of psychology at UB and co-author of the study, “As children learn to read, the brain rewires so visual areas and auditory areas move from isolated processing to coordinated teamwork.” The study appears in a special issue of Frontiers in Psychology on audio-visual processing in reading.
There is no single dedicated reading area in the brain. Written language is a recent cultural invention in evolutionary terms, so the brain repurposes older, specialized circuits. Visual regions originally evolved to recognize objects and fine visual details help discriminate letters, while auditory regions specialize in processing speech sounds. Skilled reading depends on how effectively those regions map written symbols to speech sounds.
Participants who showed the greatest gains in reading skill also exhibited the most pronounced transition from functionally isolated regions to integrated network activity. The researchers measured task-based functional connectivity with functional magnetic resonance imaging (fMRI), capturing which brain areas became active together during a reading-related task.
Functional connectivity differs from anatomical connectivity: anatomical connectivity refers to white matter tracts that physically link brain areas, whereas functional connectivity describes regions that reliably activate together during specific tasks. Functional connectivity often reflects underlying anatomical links but can also reveal dynamic patterns of coordination that support learning and skill acquisition.
The study followed 19 English-speaking children at two time points: first between ages 8 and 11, and again between ages 11 and 13, with an average interval of about 2.5 years. Reading skill at both time points was assessed using pseudoword decoding. Pseudoword reading (for example, pronouncing “glarp”) forces readers to apply letter-sound rules rather than rely on word recognition from experience, making it a sensitive measure of phonological decoding ability.
In the scanner, children completed a rhyming judgment task that required continuous mapping from visual words to sounds: they judged whether consecutively presented words rhymed. Using fMRI data collected during this task, the research team — led by graduate student Gregory J. Smith with Chris McNorgan and James R. Booth — identified which brain regions showed coordinated activity while performing reading-related processing.
The analysis applied graph-theoretic techniques commonly used to quantify organization and communication within complex networks. These metrics allowed the researchers to measure “cross-talk” among regions of the reading network and to quantify changes in network integration across development. One key finding was that decreases in network transitivity — a graph measure indicating less segregation of functional clusters — corresponded with greater integration and better reading outcomes.
“Developmentally, children show more cross-talk between sound and visual processing regions,” McNorgan explains. “Those regions become mutually reinforcing as children learn to read. When this interaction is reduced, children can struggle with reading acquisition.” The study suggests that individual differences in how functional pathways reorganize can predict how well a child learns the alphabetic principle and decoding skills.
Source: University at Buffalo
Publisher: Organized by NeuroscienceNews.com
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Original Research: Longitudinal Task-Related Functional Connectivity Changes Predict Reading Development — Gregory J. Smith, James R. Booth, and Chris McNorgan. Published in Frontiers in Psychology (open access).
DOI: 10.3389/fpsyg.2018.01754
University at Buffalo. “Reading Is a Team Effort: Different Brain Regions Working Together Predict Reading Proficiency.” NeuroscienceNews. October 3, 2018.
Abstract (rephrased)
Longitudinal evidence suggests that reading development involves a shift in how lexical processing is organized across brain regions, implying changes in inter-regional functional connectivity. This study used task-related fMRI across multiple runs of a rhyming judgment task in children aged 8–14 over approximately 2.5 years to examine developmental changes in connectivity. Changes in functional segregation — specifically decreases in segregation and increases in integration among specialized clusters — correlated with and predicted improvements in pseudoword decoding, a measure of alphabetic principle mastery. These results indicate that maturation of particular neural pathways, quantifiable using graph-theoretic metrics, underlies individual differences in reading development and that features of task-related functional networks can forecast reading progress.