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In neuroanatomy, the optic tract (from Latin tractus opticus) is a part of the visual system in the brain.It is a continuation of the optic nerve that relays information from the optic chiasm to the ipsilateral lateral geniculate nucleus (LGN), pretectal nuclei, and superior colliculus.
In humans, the optic nerve is derived from optic stalks during the seventh week of development and is composed of retinal ganglion cell axons and glial cells; it extends from the optic disc to the optic chiasma and continues as the optic tract to the lateral geniculate nucleus, pretectal nuclei, and superior colliculus.
In neuroanatomy, the optic chiasm, or optic chiasma (/ ɒ p t ɪ k k aɪ æ z əm /; from Greek χίασμα 'crossing', from Ancient Greek χιάζω 'to mark with an X'), is the part of the brain where the optic nerves cross. It is located at the bottom of the brain immediately inferior to the hypothalamus. [1]
The decussation of the optic radiation in the cortex is an example of a type IV crossing. This type is usually not called chiasm. Such a looping occurs, for example, in the optic tract between the optic chiasm and the optic tectum. [6] Another example is the optic radiation which rotates the retinal map on the visual cortex by 180° (see Figure 3).
Retina→Optic nerve→Optic chiasma (here the nasal visual field of both eyes cross over to the opposite side)→Optic tract→Lateral geniculate body→Optic radiation→Primary visual cortex The type of field defect can help localize where the lesion is located (see picture given in infobox).
The information about the image via the eye is transmitted to the brain along the optic nerve. Different populations of ganglion cells in the retina send information to the brain through the optic nerve. About 90% of the axons in the optic nerve go to the lateral geniculate nucleus in the thalamus. These axons originate from the M, P, and K ...
These axons form the optic nerve, optic chiasm, and optic tract. A small percentage of retinal ganglion cells contribute little or nothing to vision, but are themselves photosensitive; their axons form the retinohypothalamic tract and contribute to circadian rhythms and pupillary light reflex, the resizing of the pupil.
Schematic diagram of the human eye, with the optic disc, or blind spot, at the lower left. Shown is a horizontal cross section of the right eye, viewed from above. A normal optic disc is orange to pink in colour and may vary based on ethnicity. [3] A pale disc is an optic disc which varies in colour from a pale pink or orange colour to white. A ...