SEE THE LETTERS
As the student reads the words in the passage their brain is performing a complex process of converting electrical signals from the retina of the eye into implulse that identify the shape and postion of the markings on the page before the meaning of those shapes and markings can be interpreted.
The eyes see markings on a page, but how does the brain "see" letters and thus, words?
As a student reads the letters that form words on the page, light enters the retina and activates the visual receptors that produce signals which travel via the optic nerve to the superior colliculus and lateral geniculate nucleus (LGN) of the thalamus (Pinel & Edwards, 2008). Before reaching the thalamus, the crossing over of signals in the optic chiasm results in the sensory information in the left visual field projecting to the right hemisphere and vice versa for the right visual field (Hale & Fiorelli, 2004).
The information travels to the thalamus via two pathways to the primary visual area of the occipital lobe. One is the M-pathway which processes motion and contrast (Hale & Fiornelli, 2004). Letters on a page are not moving but the M-pathway would process the contrast of the letters from the page which would help the student identify the letters and other markings on the page that need to be interpreted in order to comprehend meaning.
Extending beyond the occipital lobe, the dorsal stream, which connects the occipital to the parietal lobe using the superior longitudinal fasciculus, helps identify the “where” of what the student sees (Hale & Fiornelli, 2004) which in this case would be the location and organization of letters and punctuation on a page. Because there is no movement of the letters, there would be little cognitive demand in this area. The ventral stream however, would be much busier since it connects the occipital to the temporal lobe and uses the inferior longitudinal fasciculus, to identify the “what” of the object (Hale & Fornelli, 2004). Knowing the position, color, size will ultimately help the student to correctly identify the letters, words and punctuation on a page.
The P-pathway takes sensory information from thalamus to the the occipital lobe to process orientation, location and color. The superior colliculus (aided by the pulvinar) provides the detection and orientation of the visual stimuli (Hale & Fiornelli, 2004). The P-pathway will transmit information so the student’s occipital lobe can process the size, shape and color of the letters and punctuation.
​The primary visual cortex receives and organizes the information while the association visual cortex interprets the information (Hale & Fiornelli, 2004). What are the shapes of the letters, organization of the text and symbols representing punctuation? These are important distinctions that the frontal lobe will need to determine an appropriate response.
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Figure 1 shows the the pathway of the signals from the retina to the visual cortex. Retrieved from: https://visionhelp.files.wordpress.com/2018/07/brain-visual-pathway-graphic.jpg
The Reading Passage
In the case of our reading quiz, a student would read the passage and note the vocabulary word highlighted.
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The passage is taken from the short story "The Novitiate" by Jean Howarth. It is the story of a young girl who goes gopher hunting with her older brother. In the process of trying to impress her older brother, she is caught between the horror of seeing an animal die and her need to be accepted by her brother.
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Retrieved from: https://archive.org/stream/grade9achieveme1990albe_0/grade9achieveme1990albe_0_djvu.txt
Figure 1 shows the path of the signals from the retina to the visual cortex.