This simple graphic from the current issue of Lapham’s Quarterly shows the seven key brain structures involved in reading: 1) angular gyrus, 2) fusiform gyrus, 3) Broca’s area, 4) prefrontal cortex, 5) hippocampus, 6) Wernicke’s area, and last but not least … 7) visual cortex.
1 Located in the parietal lobe, the angular gyrus facilitates communication between different parts of the brain, permitting humans to simultaneously recognize, understand, and remember words on a page.
2 The fusiform gyrus is important in the recognition of familiar shapes in different contexts, such as that of letters and words, regardless of typeface, weight, and capitalization.
3 Crucial for speech function, Broca’s area, in the brain’s left hemisphere, allows humans to read out loud and also plays a role in language comprehension.
4 Situated at the very front of the brain, the prefrontal cortex stores information in the working memory and controls selective attention, allowing humans to focus on a text.
5 Embedded deep inside the temporal lobe, the hippocampus forms explicit, nonemotional memories, allowing humans to recall facts learned from reading a book long after they finish it.
6 Governing the comprehension of spoken and written words, the structure known as Wernicke’s area is believed to translate meaningless phonemes such as l, o, and ve into meaningful words like love.
7 Connected to the eyes by optic nerves, the visual cortex detects, processes, and recognizes visual information from the outside world.
Reading, by Pierre-Auguste Renoir, c. 1890–1895. Louvre Museum, Paris, France
Salient anatomy referenced. The real story becomes clear when we consider what the reader does. The real story is efferent with scant afferent contribution. There are three basic types of readers, all use the same “equipment.”
Type I: Predictive Imagers lead with PFC making predictive imagery, followed by brief saccades, in search of anticipated confirmatory keywords, mostly nouns and verbs. Mind leads eyes. High metabolic activity of PFC, angular gurus, and fusiform gurus (which exerts inhibitory feedback to striate cortex rendering the reader essentially word blind similar to supplemental eye field during saccade). Type I reader is consumed with imagery with little or no awareness of words and thus low Broca’s activation. Big imagery, low word, and no decoding in conscious awareness.
Type II: Serial Sub vocalizers . Eyes lead mind. Type II readers fixate nearly all words, convert text to subvocalized speech, word by word, listen to themselves, and with what working memory remains, construct imagery. They are slow, often re-read for lack of comprehension, and tire quickly. Lots of Broca’s, some angular gurus, minimal fusiform, and moderate PFC activation. Words compete with imagery for conscious awareness.
Type III: Serial Decoders. These unfortunates , having taken the advice of nearly everyone on their unhappy reading journey, are left with nearly all working memory, consumed with phonologic decoding. They fixate syllabically and read only when an overseer forces them into the dismal exercise, and reasonably so, as the fruit of reading is entirely lost upon them. Decoding defeats all else.
The eye movement patterns we record make perfect sense with efferent analysis. By the time we see these patients, poor eye movements are more likely the result, than cause, of poor reading.
All that said, it is still up to heroic developmental optometrists to save the world, as epigenetic timing, not instruction or intellect, determines which type reader one becomes. Solid visual competence (VC) prior to initial reading instruction yields
Type I, Marginal VC—> Type II, and incompetent VC—> Type III.
Too bad we are typically in poor temporal position to exert our preventative expertise. Our remedial efforts should be extended beyond removing visual skill deficit into education. Routinized strategic error (types II & III) should be addressed for maximum benefit. It is an easy addition to all practices and in my opinion should be embraced, as this information is largely unknown, outside our field. As you know, I know this, first hand.
Dangerously oversimplified and lacking critical elements. Apparently brainstem and vestibular function are unimportant. The references to Broca/Wernicke are outdated…
I am a very simple man. You got me there.
First, I mean no harm, only hoping to be of benefit. If my comments came across as pompous, I apologize. That said, allow me to simplify with my brand of poetry so as to avoid mistaken identity. I calls ‘em as I sees ‘em, and I hits ‘em where they ain’t, and nothin’ you cain’t spell will work.
Just commenting on what I have found to be true from clinical and K-12 experience with populations of substantial size over many years. My neuroscience conjectures are just that, but supported by what I have studied and make good sense to me. I am certainly open to enlightenment by better explanations, but until I see one, I’ll stick to Occam’s razor.