How To Build A Better Reading Network
If you're the type who enjoys picking up a science communication article to read (and we think you might be) then reading itself might be second nature to you. Most of us learn to read easily, so it may seem as if the human brain was designed for it. However, the real story is more complicated. Unlike language or face recognition — which are innate — our brains aren't born with regions that are dedicated to reading. Instead, the brain constructs its own 'reading network' as we learn to read. It seems amazing, then, that reading still comes so naturally to most of us.
How the brain achieves this feat is still a bit of a mystery, too. Figuring out this mystery may be the key to improving literacy across the world. The reading network is not contained within one separate area, but spans across different brain regions that handle visual, language, and attentional tasks. Scientists have developed many useful neuroimaging techniques that give them a peek at what the brain is doing during reading. One method known as functional connectivity shows us which regions of the brain have forged connections with each other. This is particularly useful when we want to study something like the reading network which is spread across the brain!
Functional connectivity uses information from scans that measure blood flow in the brain. Brain regions that work together to complete the same tasks also tend to activate at the same time. This relationship can be measured by looking at blood flow across the brain. Highly similar blood flow patterns between two brain regions shows that the regions share a similar function or job. There is an old saying for this in the neuroscience world: what fires together, wires together. Simply put, it means brain regions that work together often build stronger connections over time.
Over the years, researchers have gotten a pretty good idea of which brain regions connect to make the reading network [1]. However, researchers are still looking to figure out how certain connections within the reading network improve specific reading skills. Which functional connections are important for skills like sight word reading or reading comprehension? And how do these connections differ in children who are struggling to learn to read? For Dr. Alex Cross, a former PhD student in the Language Reading and Cognitive Neuroscience Lab at Western University, these questions were ones worth asking.
To answer their questions, Cross and her colleagues ran a study that compared the strength of the reading network’s connectivity to the reading skills of children. This allowed them to see how communication between brain regions directly impacts reading skills. They recruited 83 children from across southern Ontario for the study. Children ranged in age from 8 to 14 years and included both strong and struggling readers.
Once recruited to the study, participants did some reading tasks, which tested skills like phonetic decoding (sounding out new words), passage comprehension, and attention. Each of these skills can greatly affect overall reading success so it was important to measure them separately. Afterwards, participants had their resting state brain activity recorded in an MRI so that functional connectivity between brain regions could be calculated. Resting state means no task was given to the participants while their brain activity was recorded. The functional connectivity of participant brains at rest was then compared to their reading skills.
What researchers found described key differences in the reading networks of strong readers and struggling readers.
In strong readers, better phonetic decoding skill was related to better functional connectivity from the precentral gyrus to other areas in the reading network. The precentral gyrus is a motor region in the brain that aids with the proper pronunciation of words. Stronger connections between this motor region and the rest of the reading network seems to improve the skills that help us sound out words as they’re read. This finding makes a lot of sense and fits perfectly with other studies that have shown how important decoding skills are for developing readers [2]. In fact, as Cross’ study found, decoding skills are so important to reading development they help strengthen connections within the reading network itself.
But what about struggling readers? Here, the study found that functional connectivity is not always a good thing. Instead of helping to improve reading skills, some connections between regions can actually be a hindrance to them. In particular, stronger functional connectivity from the thalamus to regions of the brain responsible for auditory attention resulted in poorer reading speed and comprehension. This negative relationship suggests poor readers may be relying too much on connections that are not efficient.
The thalamus is a very important brain region for sensory processing. In reading it helps us recognize the letters we see. But strong readers don't need to focus on every individual letter in order to read a sentence properly. In fact, focusing that hard may make it more difficult to read fluidly. A stronger connection between the thalamus and reading network might be helpful when children are first learning to read. However, these early connections lose effectiveness over time.
As the study shows, the brain can forge both helpful and not-so-helpful connections during reading development. Struggling readers may continue to rely on inefficient connections to read, making the task much more difficult for them. As you can see, neuroimaging techniques provide a valuable tool for us to understand how the brain operates in readers of different skill levels. But can this information be helpful towards improving literacy in those struggling readers?
Yes, it actually can!
Connections made between brain regions are not set in stone. They can be changed over time through good reading instruction and practice. Research like Dr. Cross’ shows scientists and educators which reading skills can be used improve those beneficial connections within the reading network. That knowledge can be used for better reading instruction and make learning easier and more long-lasting for students.
One reading skill that may be particularly useful to focus on is phonetic decoding, which was associated with stronger reading network connectivity in better readers. Reading instruction that focuses on phonetic decoding can help strengthen helpful connections and reduce reliance on unhelpful ones [3]. Neuroimaging research doesn’t just show us how the brain works, it also helps us crack the code on effective learning. Reading might be second nature to you and I, but the brain is doing a lot of work under the surface to make that so!
Featured article: Cross, A. M., Ramdajal, R., Peters, L., Vandermeer, M. R. J., Hayden, E. P., Frijters, J. C., Steinbach, K. A., Lovett, M. W., Archibald, L. M. D., & Joanisse, M. F. (2021). Resting-state functional connectivity and reading subskills in children. NeuroImage, 243, 118529. https://doi.org/10.1016/j.neuroimage.2021.118529
Additional references:
[1] Pugh, K. R., Mencl, W. E., Jenner, A. R., Katz, L., Frost, S. J., Lee, J. R., Shaywitz, S. E., & Shaywitz, B. A. (2001). Neurobiological studies of reading and reading disability. Journal of Communication Disorders, 34(6), 479–492. https://doi.org/10.1016/S0021-9924(01)00060-0
[2] Seidenberg, M. S., & McClelland, J. L. (1989). A distributed, developmental model of word recognition and naming. Psychological Review, 96(4), 523–568. https://doi.org/10.1037/0033-295X.96.4.523
[3] Jack M. Fletcher, Karla K. Stuebing, Amy E. Barth, Carolyn A. Denton, Paul T. Cirino, David J. Francis & Sharon Vaughn (2011) Cognitive Correlates of Inadequate Response to Reading Intervention, School Psychology Review, 40:1, 3-22. https://doi.org/10.1080/02796015.2011.12087725