 the optic tract (from the 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. optic tract. encyclopedia britannica. retrieved from: http://www.britannica.com/ebchecked/topic/430336/optic-tract (accessed nov 1, 2013). it is composed of two individual tracts, the left optic tract and the right optic tract, each of which conveys visual information exclusive to its respective contralateral half of the visual field. each of these tracts is derived from a combination of temporal and nasal retinal fibers from each eye that corresponds to one half of the visual field. in more specific terms, the optic tract contains fibers from the ipsilateral temporal hemiretina and contralateral nasal hemiretina. ==visual system== the optic tract carries retinal information relating to the whole visual field. specifically, the left optic tract corresponds to the right visual field, while the right optic tract corresponds to the left visual field. to form the right visual field, temporal retinal fibers from the left eye and nasal retinal fibers from the right eye form the left optic tract, and to form the left visual field, temporal retinal fibers from the right eye and nasal retinal fibers from the left eye form the right optic tract. chudler e. (2011). visual pathway. neuroscience for kids. retrieved from: http://faculty.washington.edu/chudler/vispath.html (accessed july 28, 2014). {| class="wikitable" | optic tract || visual field || temporal retinal fibers || nasal retinal fibers |- | left || right || left || right |- | right || left || right || left |} ==autonomics== several autonomic ocular motor responses are consensual. the optic tract is primarily responsible relaying visual information to the lgn, but it is also peripherally responsible for transducing these bilateral autonomic reflexes, including the pupillary light reflex and pupillary dark reflex. dragoi v. (1997). chapter 7: ocular motor system. neuroscience online. retrieved from: http://neuroscience.uth.tmc.edu/s2/chapter15.html (accessed nov 2, 2013). ===pupillary light reflex=== the pupillary light reflex is an autonomic reflex that controls pupil diameter to accommodate for increases in illumination as perceived by the retina. higher light intensity causes pupil constriction, and the increase of light stimulation of one eye will cause pupillary constriction of both eyes. the neural circuitry of the pupillary light reflex includes the optic tract which joins the optic nerve to the brachium of the superior colliculus
Cerebrum Visual_system