Optic Nerve Visual Pathway and Orbit I Optic Nerve and Visual Pathway

Similarly to the olfactory system, the optic nerve is not a peripheral nerve, as it is mostly an evagination of the telencephalon. Retinic photoreceptors, cones and rods, relay the signal for further processing to other retinic neurons: bipolar cells, horizontal cells, amacrine cells, retinal ganglion cells, and interplexiform cells. Axons from the ganglion cells form the optic nerve. The potentials generated are transmitted via the optic nerve to the lateral geniculate nucleus (visual information), superior colliculus (somatic reflexes), and pretectal areas (autonomic reflexes). In mammals, visual information is relayed to the thalamic lateral geniculate body, from which optic information is directed to the primary visual cortex through the geniculo-striate projection, or optic radiation. In humans, the cortical area surrounds both walls of the calcarine fissure, extending to the adjacent cortex (area 17). Visual information is topographically oriented. The right visual field, for instance, activates neurons of the left retina (medial in the left eye, lateral in the right one). The pulse is then transmitted to the left geniculate body and the left occipital cortex. The upper portions of the visual field are laterally projected in the geniculate body and become inferior in optic radiation and pericalcarine cortex.

Medial Olfactory Olfactory olfactory stria tract bulb

Olfactory tubercle

Lateral olfactory stria

Diagonal band

Anterior commissure

Inferior thalamic peduncle

Medial telencephalic fasciculus

Stria medullaris of thalamus

Medial nucleus of thalamus

Habenular commissure

Diagonal band

Anterior commissure

Inferior thalamic peduncle

Medial telencephalic fasciculus

Stria medullaris of thalamus

Medial nucleus of thalamus

Habenular commissure

Lateral Olfactory Band

— Anterior perforated substance

Habenular nucleus

Lateral area of hypothalamus

Ventral amygdalofugal fibers

Semilunar gyrui

Gyrus ambiens

Semilunar gyrui

Gyrus ambiens

Entorhinal area

— Anterior perforated substance

Anterior nucleus Lateral nucleus Central nucleus Medial nucleus Basal nucleus (accessor! us) Cortical nucleus

— Amygdaloid body

Habenular nucleus

Lateral area of hypothalamus

Ventral amygdalofugal fibers

Lateral olfactory tract i Primary olfactory area Secondary olfactory area

Crista galli Olfactory groove Cribriform plate of ethmoid bone ^

Anterior Perforated Substance
Anterior perforated substance

Eyeball

Optic nerve

Optic chiasm

Optic tract

Optic radiation, temporat knee

Optic radiation

Stria saglttalis

Geniculate Nerve Knee
Temporal field

Optic tract, medial root

Optic tract, lateral root

Lateral geniculate body

Striate area

Calcarine fissure

Optic nerve internal carotid artery

Carotid canal

Anterioretinoid process

Anterior clinoid process Ophthalmic artery Foramen ovale

Carotid canal

Optic nerve

Anterioretinoid process internal carotid artery

Anterior clinoid process Ophthalmic artery Foramen ovale

Superior lingual Descendens Calcarlne gyrus (05) gyrus (of Ecker) fissure

Striate cortex

Optic chiasm internal carotid artery

Optic tract

Top of the basilar artery and posterior cerebral artery

Optic nerve

Optic chiasm

Optic tract

Mammillary body

Optic nerve

Optic chiasm

Optic tract

Mammillary body

Infundibular recess Internal carotid of the third ventricle artery

Optic nerve

Middle cerebral artery

Optic chiasm

Optic tract

Infundibular recess of the third ventricle

Mammillary bodies

Optic nerve

Middle cerebral artery

Optic chiasm

Optic tract

Infundibular recess of the third ventricle

Mammillary bodies

Optic chiasm Internal carotid artery, communicating segment
Brachium Superior Colliculus

Optic tract Optic chiasm Optic nerve

Pituitary stalk

Optic tract

Lateral geniculate body

Superior cerebellar peduncle (brachium conjunctivum)

Superior colliculus

Caicarine fissure

Cuneus Descendens Retrocalcarine

(06) gyrus (of Ecker) fissure

Optic tract

Lateral geniculate body

Superior cerebellar peduncle (brachium conjunctivum)

Superior colliculus

Caicarine fissure

Striate cortex

Cuneus Descendens Retrocalcarine

(06) gyrus (of Ecker) fissure

Lingual fissure Caicarine fissure Descendens gyrus (of Ecker)

Lingual fissure Caicarine fissure Descendens gyrus (of Ecker)

Cuneus (06)

Lateral geniculate body

Optic radiation

Cuneus (06) Retrocalcarine fissure

Cuneus (06)

Caicarine fissure

Optic radiation

Lateral geniculate body

Optic radiation

Cuneus (06) Retrocalcarine fissure

Region of activation obtained during visual stimulation white black and white drawings. (Courtesy of Massimo Caulo, MD, PhD, ITAB, Chieti, Italy)

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