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The optic chiasm or optic chiasma (Greek
Greek language

Greek is an Indo-European languages native to the southern Balkan peninsula, the language of the Greek people. It forms an independent branch within Indo-European....
 , "crossing", from the Greek 'to mark with an X', after the Greek letter '?
Chi (letter)

Chi is the 22nd letter of the Greek alphabet, pronounced as [kai] in English. Its value in Ancient Greek was an aspirated voiceless velar plosive ....
', chi) is the part of the brain
Brain

The brain is the center of the nervous system in all vertebrate, and most invertebrate, animals. Some primitive animals such as cnidarian and echinoderm have a decentralized nervous system without a brain, while sponges lack any nervous system at all....
 where the optic nerve
Optic nerve

The optic nerve, also called cranial nerve II, transmits visual information from the retina to the brain....
s partially cross.

ifically, in the optic chiasm, the nerves connected to the right eye that attend to the right temporal visual field (located in the right retina) cross to the left half of the brain, while the nerves from the left eye that attend to the left temporal visual field (located in the left retina) cross to the right half of the brain.

This allows for parts of both eyes that attend to the right visual field to be processed in the left visual system
Visual system

The visual system is the part of the central nervous system which allows organisms to visual perception.It interprets the information from visible light to build a representation of the world surrounding the body....
 in the brain, and vice versa.

a class="link1" onMouseover='showByLink("m193637",this)' onMouseout='hide("m193637")'href="http://www.absoluteastronomy.com/topics/Siamese_%28cat%29">Siamese cat
Siamese (cat)

The Siamese is one of the first distinctly recognised cat breed of Oriental Shorthair cat. The exact origins of the breed are unknown, but it is believed to be from Southeast Asia, and is said to be descended from the sacred temple cats of Siam ....
s with certain genotype
Genotype

The genotype is the trait we can't see. The genotype is the Genetics constitution of a cell, an organism, or an individual usually with reference to a specific character under consideration....
s of the albino gene, this wiring is disrupted, with less of the nerve-crossing than is normal, as a number of scholars have reported.






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The optic chiasm or optic chiasma (Greek
Greek language

Greek is an Indo-European languages native to the southern Balkan peninsula, the language of the Greek people. It forms an independent branch within Indo-European....
 , "crossing", from the Greek 'to mark with an X', after the Greek letter '?
Chi (letter)

Chi is the 22nd letter of the Greek alphabet, pronounced as [kai] in English. Its value in Ancient Greek was an aspirated voiceless velar plosive ....
', chi) is the part of the brain
Brain

The brain is the center of the nervous system in all vertebrate, and most invertebrate, animals. Some primitive animals such as cnidarian and echinoderm have a decentralized nervous system without a brain, while sponges lack any nervous system at all....
 where the optic nerve
Optic nerve

The optic nerve, also called cranial nerve II, transmits visual information from the retina to the brain....
s partially cross.

Pathways

Specifically, in the optic chiasm, the nerves connected to the right eye that attend to the right temporal visual field (located in the right retina) cross to the left half of the brain, while the nerves from the left eye that attend to the left temporal visual field (located in the left retina) cross to the right half of the brain.

This allows for parts of both eyes that attend to the right visual field to be processed in the left visual system
Visual system

The visual system is the part of the central nervous system which allows organisms to visual perception.It interprets the information from visible light to build a representation of the world surrounding the body....
 in the brain, and vice versa.

Optic chiasm in cats

In Siamese cat
Siamese (cat)

The Siamese is one of the first distinctly recognised cat breed of Oriental Shorthair cat. The exact origins of the breed are unknown, but it is believed to be from Southeast Asia, and is said to be descended from the sacred temple cats of Siam ....
s with certain genotype
Genotype

The genotype is the trait we can't see. The genotype is the Genetics constitution of a cell, an organism, or an individual usually with reference to a specific character under consideration....
s of the albino gene, this wiring is disrupted, with less of the nerve-crossing than is normal, as a number of scholars have reported. To compensate for lack of crossing in their brains, they cross their eyes (strabismus
Strabismus

Strabismus is a condition in which the eyes are not properly aligned with each other. It typically involves a lack of coordination between the Muscles of orbits that prevents bringing the gaze of each eye to the same point in space and preventing proper binocular vision, which may adversely affect depth perception....
).

This is also seen in albino tiger
Tiger

The tiger is a member of the Felidae family; the largest of the four "big cats" in the genus Panthera. Native to much of eastern and southern Asia, the tiger is an apex predator and an Carnivore#Obligate carnivores....
s, as Guillery & Kaas report.

Additional images


See also

  • Chiasmal syndrome
    Chiasmal syndrome

    Anatomy The optic chiasm is formed by the union of the two optic nerves. The nasal fibers of each optic nerve decussate across the chiasm to the opposite side while the temporal fibers course posteriorly to form the optic tract on the same side....


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