Researchers Discovered New Understanding Of The Brain Structures Associated In Reading Ability

A group of researchers investigated two ostensibly contradictory hypotheses about how brain regions connect to reading ability in a new study, and found some evidence for both of them.

According to the 'cerebral lateralization' hypothesis, the human brain is inherently asymmetrical, and some of the structures on the left side are assumed to be engaged in language processing; the stronger asymmetry everywhere, the higher one's reading skills.

However, the 'canalization theory' suggests that the presence of asymmetries in the left half of the brain simply strengthens the qualities required for reading. Having more asymmetry, on the other hand, simply puts you in the average reading skill range.

Both hypotheses appear to have merit depending on the depth of study - whether throughout the entire brain hemisphere or in individual regions.

The researchers discovered that more asymmetry in the left hemisphere did indeed improve reading skills, but only when staring at the most asymmetric structure, effectively treating the hemisphere as a whole.

Magnetic resonance imaging (MRI) data from prior study was used by researchers at the Medical University of South Carolina to find asymmetrical anatomical changes in the brains of over 700 adolescents and adults.

MRI scans construct a map of the brain by exposing anatomical structures, similar to functional magnetic resonance imaging (fMRI), which evaluates metabolic activity.

Participants were also asked to take reading skills tests, including ones that needed them to whisper out pseudowords, that are made-up words that demand more processing because our brains aren't used to them — this is known as phonological decoding.

However, the researchers discovered that if some brain regions' structural differences between the two lobes were accentuated, the person was more likely to fall within the typical reading ability range.

This is consistent with the canalization concept, which may be pictured as a needle travelling around the groove of a record following a predefined path. Protective genetic processes would kick in to generate the essential brain asymmetries in the case of language interpretation and reading.