Brain functions involved in reading

The ability to read is fundamental in the educational process and in active participation in society. However, reading is not an innate skill; it is a complex process that involves several areas of the brain.

In this session, we will explore in detail the brain functions involved in reading, from the decoding of words to the comprehension of text, highlighting the importance of understanding how the brain processes written information.

Word Decoding in the Fusiform Gyrus

• Fusiform Gyrus and Visual Processing: The fusiform gyrus, a region of the temporal lobe, plays a crucial role in the visual recognition of words. This area specializes in processing visual information, allowing for the rapid identification of written words. The ability to distinguish letters and recognize visual patterns is essential for effective word decoding during reading.

• Processing of Letters and Words: The process begins with the identification and processing of individual letters. The fusiform gyrus works in conjunction with other visual regions to recognize specific patterns that represent letters and words. This visual decoding process is an initial component in the neurobiological pathway of reading.

The Phonological Route and the Angular Gyrus

• Angular Gyrus and Phonological Processing: The angular gyrus, located in the inferior parietal lobe, is closely linked to phonological processing during reading. This region is essential for converting the visual symbols of letters into sounds, which allows for the pronunciation of words. The phonological route is fundamental for the development of reading skills, as it connects the visual form of words with their auditory representation.

• Association Between Letters and Sounds: During reading, the phonological route establishes associations between letters and sounds, allowing for the pronunciation of words even for those that are not frequently used. This process is essential for reading new words and contributes to reading fluency as learning progresses.

Neural Connections in the Corpus Callosum

• Corpus Callosum and Hemispheric Coordination: Reading involves coordination between the brain hemispheres, and the corpus callosum plays a crucial role in facilitating communication between them. This bundle of nerve fibers connects the left and right hemispheres, allowing for the transfer of information related to reading. Hemispheric coordination is essential for efficient and rapid processing of visual and phonological information.

• Integration of Visual and Auditory Information: Through the corpus callosum, visual information processed in the fusiform gyrus is integrated with phonological information from the angular gyrus. This integration is fundamental for effective reading, as it allows for the comprehension of written words while they are pronounced in the mind.

The Lexical Route and the Inferior Frontal Gyrus

• Inferior Frontal Gyrus and Lexical Processing: The inferior frontal gyrus, located in the frontal lobe, plays a role in lexical processing during reading. This region is associated with access to the mental lexicon, which contains words stored in memory. The lexical route is crucial for recognizing familiar words and accessing the meaning associated with each word.

• Access to Meaning and Reading Comprehension: As words are recognized in the mental lexicon, connections with their corresponding meanings are activated. The inferior frontal gyrus contributes to semantic access, allowing for reading comprehension by linking words with their meaning. This process is essential for going beyond decoding and truly understanding the content of the text.

Connections with the Memory and Attention System

• Parietal Cortex and Working Memory Functions: The parietal cortex, especially the area associated with working memory functions, is essential for the temporary retention of information during reading. Working memory allows for keeping words and ideas active while progressing through the text, facilitating the comprehension of sentences and paragraphs.

• Involvement of the Attention System: The attention system, which encompasses various regions of the brain, plays a crucial role in reading. The ability to focus attention on specific words, switch between different aspects of the text, and maintain sustained attention are fundamental skills for efficient processing during reading.

Neural Plasticity and Reading Acquisition

• Neural Plasticity in Childhood: During childhood, the brain exhibits remarkable neural plasticity, meaning it has the ability to reorganize and adapt in response to new experiences, such as learning to read. Synaptic connections strengthen as reading skills develop.

• Development of Specialized Circuits: As a child learns to read, specialized brain circuits develop to efficiently process written information. These circuits are refined over time as reading is practiced, facilitating greater speed and accuracy in processing.

Brain Dysfunctions and Reading Challenges

• Dyslexia and Challenges in the Phonological Route: Dyslexia, a learning disorder, is often associated with dysfunctions in the phonological route. Difficulties in associating letters with sounds and problems in word pronunciation are common in individuals with dyslexia. Understanding these dysfunctions is crucial for developing effective interventions.

• Visual Processing Disorders and Word Recognition: Some visual processing disorders can affect the ability to recognize written words. Difficulties in the fusiform gyrus can lead to problems in visual decoding, which directly impacts reading.