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Ocular dominance, sometimes called eye preference or eyedness, [1] is the tendency to prefer visual input from one eye to the other. [2] It is somewhat analogous to the laterality of right- or left- handedness ; however, the side of the dominant eye and the dominant hand do not always match. [ 3 ]
Ocular dominance columns are stripes of neurons in the visual cortex of certain mammals (including humans [1]) that respond preferentially to input from one eye or the other. [2] The columns span multiple cortical layers , and are laid out in a striped pattern across the surface of the striate cortex (V1).
Ocular dominance columns are also found in the striate cortex. These columns were found to prefer crossing iso-orientation lines perpendicularly. During microelectrode experiments, it is normal to see penetrations where eye dominance changes between the contralateral eye and ipsilateral eye but this does not interrupt the orientation sequence. [7]
The layers representing the deprived eye in the lateral geniculate nucleus of the thalamus are atrophied. In V1, ocular dominance columns representing the open eye are dramatically enlarged, at the expense of cortical surface area representing the sutured eye (Fig. 1 - Effect of monocular deprivation on ocular dominance columns. Light areas ...
Binocular rivalry was discovered by Porta. [6] Porta put one book in front of one eye, and another in front of the other. He reported that he could read from one book at a time and that changing from one to the other required withdrawing the "visual virtue" from one eye and moving it to the other.
There are many types of topographic maps in the visual cortices, including retinotopic maps, ocular dominance maps and orientation maps. Retinotopic maps are the easiest to understand in terms of topography. Retinotopic maps are those in which the image on the retina is maintained in the cortices (V1 and the LGN).
Furthermore, individual V1 neurons in humans and other animals with binocular vision have ocular dominance, namely tuning to one of the two eyes. In V1, and primary sensory cortex in general, neurons with similar tuning properties tend to cluster together as cortical columns .
If the brain never learns to see objects in detail, then there is a high chance of one eye becoming dominant. The result is that the brain will block the impulses of the non-dominant eye. In contrast, the child with myopia can see objects close to the eye in detail and does learn at an early age to see objects in detail. [medical citation needed]