Optic tract

Optic tract
Brain: Optic tract
Gray773.png
The left optic nerve and the optic tracts.
Latin tractus opticus
Gray's subject #189 814
Part of Visual system
NeuroNames hier-443
NeuroLex ID birnlex_1684

The optic tract is a part of the visual system in the brain.

It is a continuation of the optic nerve and runs from the optic chiasm (where half of the information from each eye crosses sides, and half stays on the same side) to the lateral geniculate nucleus.

Right vs. left

The relationships of the retinal fibers to the optic tracts are illustrated below, with the nasal retinal fibers in blue and the temporal retinal fibers in red.

Click for a larger image.
optic tract temporal retinal fibers nasal retinal fiber
right optic tract from the right eye from the left eye
left optic tract from the left eye from the right eye

In split-brain patients whom have undergone a corpus callosotomy (usually to treat severe epilepsy) the information from one optic tract does not get transmitted to both hemispheres. In carefully controlled experiments, split brain patients shown an image in his or her left left visual field (that is, the left half of what both eyes see), will be unable to vocally name what he or she has seen as the speech-control center is in the left brain hemisphere in most people. See the main article, split-brain.

Pathology

A lesion in the left optic tract will cause right-sided homonomous hemianopsia.

Additional images

  • Diagram of hippocampus

  • Schematic diagram of the primate lateral geniculate nucleus.

  • Superficial dissection of brain-stem. Ventral view.

  • Coronal section of brain through intermediate mass of third ventricle.

  • Hind- and mid-brains; postero-lateral view.

  • Scheme showing central connections of the optic nerves and optic tracts.

  • Base of brain.

  • Section of brain showing upper surface of temporal lobe.

  • Dissection showing the course of the cerebrospinal fibers.

  • Human brainstem anterior view

  • Optic tract and optic nerve

v · d · eSensory system: Visual system and eye movement pathways
Visual perception
1° (Bipolar cell of Retina) → 2° (Ganglionic cell) → 3° (Optic nerve → Optic chiasm → Optic tract → LGN of Thalamus) → 4° (Optic radiation → Cuneus and Lingual gyrus of Visual cortex → Blobs → Globs)
Muscles of orbit
Tracking
Horizontal gaze
Vertical gaze
Pupillary reflex
Pupillary dilation
Circadian rhythm

M: EYE

anat(g/a/p)/phys/devp/prot

noco/cong/tumr, epon

proc, drug(S1A/1E/1F/1L)
v · d · eNervous system: Sensory systems / senses (TA A15)
Special senses
Touch
Other
v · d · eNerves of head and neck: the cranial nerves and nuclei (TA A14.2.01, GA 9.855)
olfactory (AON->I)
optic (LGN->II)
optic chiasm · optic tract
oculomotor
(ON, EWN->III)
trochlear (TN->IV)
no significant branches
trigeminal
(PSN, TSN, MN, TMN->V)
abducens (AN->VI)
no significant branches
facial (FMN, SN, SSN->VII)
near origin
vestibulocochlear
(VN, CN->VIII)
glossopharyngeal
(NA, ISN, SN->IX)
ganglia (superior, inferior)
vagus
(NA, DNVN, SN->X)
ganglia (superior, inferior)
accessory (NA, SAN->XI)
hypoglossal (HN->XII)

M: PNS

anat(h/r/t/c/b/l/s/a)/phys(r)/devp/prot/nttr/nttm/ntrp

noco/auto/cong/tumr, sysi/epon, injr

proc, drug(N1B)



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Look at other dictionaries:

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  • Optic chiasm — Brain: Optic chiasm Visual pathway with optic chiasm (X shape outlined, red) (1543 image from Andreas Vesalius Fabrica) Latin chiasma opticum Gray s …   Wikipedia

  • tract — An elongated area, e.g., path, track, way. SEE ALSO: fascicle. SYN: tractus. [L. tractus, a drawing out] alimentary t. SYN: digestive t.. anterior corticospinal t. uncrossed fibers forming a small bundle in the anterior funiculus of the …   Medical dictionary

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  • optic nerve — Anat. either one of the second pair of cranial nerves, consisting of sensory fibers that conduct impulses from the retina to the brain. See illus. under eye. [1605 15] * * * ▪ anatomy   second cranial nerve, which carries sensory nerve impulses… …   Universalium

  • optic nerve — noun the cranial nerve that serves the retina • Syn: ↑nervus opticus, ↑second cranial nerve, ↑optic tract • Hypernyms: ↑cranial nerve • Part Holonyms: ↑visual system, ↑ …   Useful english dictionary

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