optic nerve connects to what part of the brain
Law of specific nerve energies


of the brain to which nerves deliver their action potentials (e.g., light from nerves arriving at the visual cortex and sound from nerves arriving at the auditory cortex). In 1945, Roger Sperry showed that it is the location in the brain to which nerves attach that determines experience. He studied amphibians whose optic nerves cross completely, so that the left eye connects to the right side of the brain and the right eye connects to the left side of the brain. He was able to cut the optic nerves and cause them
14568632
Human brain


uncertain. Motor connections from the brain to the spinal cord, and sensory connections from the spinal cord to the brain, both cross sides in the brainstem. Visual input follows a more complex rule: the optic nerves from the two eyes come together at a point called the optic chiasm, and half of the fibres from each nerve split off to join the other. The result is that connections from the left half of the retina, in both eyes, go to the left side of the brain, whereas connections from the
16628494
Optic chiasm


The optic chiasm or optic chiasma (; Greek , "crossing", from the Greek 'to mark with an X', after the Greek letter 'Χ', "chi") is the part of the brain where the optic nerves partially cross. The optic chiasm is located at the bottom of the brain immediately inferior to the hypothalamus. The optic chiasm is found in all vertebrates, although in cyclostomes (lampreys and hagfishes) it is located within the brain. The optic nerve fibres on the nasal sides of each
16443104
Eye


an object directly. Cone cells and rods are connected through intermediate cells in the retina to nerve fibres of the optic nerve. When rods and cones are stimulated by light, they connect through adjoining cells within the retina to send an electrical signal to the optic nerve fibres. The optic nerves send off impulses through these fibres to the brain. The pigment molecules used in the eye are various, but can be used to define the evolutionary distance between different groups, and can also be an aid in determining which are closely related
192490
Posterior ischemic optic neuropathy


pial branches of the ophthalmic artery. The optic canal, a boney tunnel leading to the brain, surrounds the most posterior part of this optic nerve segment. The anterior optic nerve receives blood primarily from the posterior ciliary arteries. The anterior optic nerve, a.k.a. the optic nerve head, is surrounded by the scleral canal, and is vulnerable to crowding of nerve fibers. The portion of the optic nerve head that is visible by looking into the eye with an ophthalmoscope is called the optic disc. At the onset of symptoms
20484732
Optic nerve hypoplasia


Optic nerve hypoplasia (ONH) is a medical condition arising from the underdevelopment of the optic nerve(s). This condition is the most common congenital optic nerve anomaly. The optic disc appears abnormally small, because not all the optic nerve axons have developed properly. It is often associated with endocrinopathies (hormone deficiencies), developmental delay, and brain malformations. The optic nerve, which is responsible for transmitting visual signals from the retina to the brain, has approximately 1.2 million nerve fibers in the average person. In those diagnosed with
3344646
Optic nerve


the other eleven cranial nerves and considered to be part of the peripheral nervous system. The optic nerve is ensheathed in all three meningeal layers (dura, arachnoid, and pia mater) rather than the epineurium, perineurium, and endoneurium found in peripheral nerves. Fiber tracts of the mammalian central nervous system (as opposed to the peripheral nervous system) are incapable of regeneration, and, hence, optic nerve damage produces irreversible blindness. The fibers from the retina run along the optic nerve to nine primary visual nuclei in the brain
19187989
Optic disc drusen


Optic disc drusen (ODD) are globules of mucoproteins and mucopolysaccharides that progressively calcify in the optic disc. They are thought to be the remnants of the axonal transport system of degenerated retinal ganglion cells. ODD have also been referred to as congenitally elevated or anomalous discs, pseudopapilledema, pseudoneuritis, buried disc drusen, and disc hyaline bodies. The optic nerve is a cable connection that transmits images from the retina to the brain. It consists of over one million retinal ganglion cell axons. The optic nerve head, or optic disc
4996121
Papilledema


the following: As the optic nerve sheath is continuous with the subarachnoid space of the brain (and is regarded as an extension of the central nervous system), increased pressure is transmitted through to the optic nerve. The brain itself is relatively spared from pathological consequences of high pressure. However, the anterior end of the optic nerve stops abruptly at the eye. Hence the pressure is asymmetrical and this causes a pinching and protrusion of the optic nerve at its head. The fibers of the retinal ganglion cells of the optic disc
20356776
OPN1LW


reactions. This reaction series passes from the LWS cone cells into horizontal cells, bipolar cells, amacrine cells, and finally ganglion cells before continuing to the brain via the optic nerve. Ganglion cells compile the signal from the LWS cones with all other cone signals that occurred in response to the light that was seen, and pass the overall signal into the optic nerve. The cones themselves do not process colour, it is the brain that decides what colour is being seen by the signal combination it receives from the ganglion cells.
16104186
Optic nerve


The optic nerve, also known as cranial nerve II, or simply as CN II, is a paired cranial nerve that transmits visual information from the retina to the brain. 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. The optic nerve has been classified as the second
19187987
Sclera


the posterior five-sixths of the connective tissue coat of the globe. It is continuous with the dura mater and the cornea, and maintains the shape of the globe, offering resistance to internal and external forces, and provides an attachment for the extraocular muscle insertions. The sclera is perforated by many nerves and vessels passing through the posterior scleral foramen, the hole that is formed by the optic nerve. At the optic disc the outer two-thirds of the sclera continues with the dura mater (outer coat of the brain
8423300
Septo-optic dysplasia


Septo-optic dysplasia (SOD), is a rare congenital malformation syndrome featuring underdevelopment of the optic nerve, pituitary gland dysfunction, and absence of the septum pellucidum (a midline part of the brain). Two of these features need to be present for a clinical diagnosis — only 30% of patients have all three. De Morsier first recognized the relation of a rudimentary or absent septum pellucidum with hypoplasia of the optic nerves and chiasm in 1956. Neuroradiologically, intracranial malformations associated with septo-optic dysplasia include agenesis of the
19075552
Alcmaeon of Croton


establishing the connection between the brain and the sense organs, and outlined the paths of the optic nerves as well as stating that the brain is the organ of the mind. Many scholars believe that Plato referred to Alcmaeon's work, when writing in Phaedo about the senses and how we or animals think. He also stated that the eye contains both fire and water, with vision occurring once something is seen and reflected by the gleaming and translucent part of the eye. Alcmaeon said that sleep occurs by the withdrawal of blood,
10623896
Bird vision


. In 54% of birds, including birds of prey, kingfishers, hummingbirds and swallows, there is second fovea for enhanced sideways viewing. The optic nerve is a bundle of nerve fibres which carry messages from the eye to the relevant parts of the brain. Like mammals, birds have a small blind spot without photoreceptors at the optic disc, under which the optic nerve and blood vessels join the eye. The pecten is a poorly understood body consisting of folded tissue which projects from the retina. It is well supplied with
7611526
Visual system


ocular system of the central nervous system. In the presence of light, the retinal molecule changes configuration and as a result a nerve impulse is generated. 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 ganglion cells in the
9659663
Visual system


the optic nerve. By contrast, layers two, three and five (2, 3, & 5) of the LGN connect to the M cells and P (parvocellular) cells of the optic nerve for the same side of the brain as its respective LGN. Spread out, the six layers of the LGN are the area of a credit card and about three times its thickness. The LGN is rolled up into two ellipsoids about the size and shape of two small birds' eggs. In between the six layers are
9659669
Anterior ischemic optic neuropathy


the field have come to a consensus that most cases involve two main risk factors. The first is a predisposition in the form of a type of optic disc shape. The optic disc is where the axons from the retinal ganglion cells collect into the optic nerve. The optic nerve is the bundle of axons that carry the visual signals from the eye to the brain. This optic nerve must penetrate through the wall of the eye, and the hole to accommodate this is usually 20-30% larger than the nerve diameter.
19768508
Eye


and transmits these signals to the brain through complex neural pathways that connect the eye via the optic nerve to the visual cortex and other areas of the brain. Eyes with resolving power have come in ten fundamentally different forms, and 96% of animal species possess a complex optical system. Image-resolving eyes are present in molluscs, chordates and arthropods. The simplest "eyes", such as those in microorganisms, do nothing but detect whether the surroundings are light or dark, which is sufficient for the entrainment of circadian rhythms
192432
Cranial nerves


the cerebrum or forebrain, and the remaining ten pairs arise from the brainstem, which is the lower part of the brain. The cranial nerves are considered components of the peripheral nervous system (PNS), although on a structural level the olfactory (I), optic (II), and trigeminal (V) nerves are more accurately considered part of the central nervous system (CNS). Most typically, humans are considered to have twelve pairs of cranial nerves (I–XII), with the terminal nerve (0
16439924
Eye development


. As this expands, the rostral neuropore (the exit of the brain cavity out of the embryo) closes and the optic sulcus and the neural plate becomes the optic vesicle. Optic nerves arise from connections of the vesicles to the forebrain. Neuroectoderm gives rise to the following compartments of the eye: Lens development is closely related to optic vesicle development. The interaction between the growing vesicle and the ectoderm causes the ectoderm to thicken at that point. This thickened portion of the ectoderm is called the lens placode. Next, the
1987687
Posterior ischemic optic neuropathy


investigated subjects that may contribute to patient-specific susceptibility. In both types of PION, decreased blood flow leads to the death of optic nerve cells. Ischemic injury to the optic nerve causes inflammation and swelling. Because the posterior optic nerve passes through the optic canal, a bony tunnel leading to the brain, swelling in this rigid space causes compression of the optic nerve. This compression worsens ischemia and perpetuates the cycle of injury, and swelling, and compression. A-PION is caused by an inflammatory disease called giant cell
20484724
Glioma


A glioma is a type of tumor that starts in the glial cells of the brain or the spine. Gliomas comprise about 30 percent of all brain tumors and central nervous system tumors, and 80 percent of all malignant brain tumors. Symptoms of gliomas depend on which part of the central nervous system is affected. A brain glioma can cause headaches, vomiting, seizures, and cranial nerve disorders as a result of increased intracranial pressure. A glioma of the optic nerve can cause visual loss. Spinal cord gliomas can cause pain,
5253579
Optic nerve


. intracanicular part (which is the part within a bony canal known as the optic canal); and, 4. cranial part (the part within the cranial cavity, which ends at the optic chiasm). From the lateral geniculate body, fibers of the optic radiation pass to the visual cortex in the occipital lobe of the brain. In more specific terms, fibers carrying information from the contralateral superior visual field traverse Meyer's loop to terminate in the lingual gyrus below the calcarine fissure in the occipital lobe, and fibers
19187994
Peripheral nervous system


, or by the blood–brain barrier, which leaves it exposed to toxins and mechanical injuries. The peripheral nervous system is divided into the somatic nervous system and the autonomic nervous system. In the somatic nervous system, the cranial nerves are part of the PNS with the exception of the optic nerve (cranial nerve II), along with the retina. The second cranial nerve is not a true peripheral nerve but a tract of the diencephalon. Cranial nerve ganglia originated in the CNS. However, the remaining ten cranial nerve
5198027
Optic neuritis


processed into vision. Inflammation of the optic nerve causes loss of vision, usually because of the swelling and destruction of the myelin sheath covering the optic nerve. The most common cause is multiple sclerosis or ischemic optic neuropathy due to thrombosis or embolism of the vessel that supplies the optic nerve. Up to 50% of patients with MS will develop an episode of optic neuritis, and 20-30% of the time optic neuritis is the presenting sign of MS. The presence of demyelinating white matter lesions on brain MRI at the
3087937
Visual impairment


global blindness. Eye injuries, most often occurring in people under 30, are the leading cause of monocular blindness (vision loss in one eye) throughout the United States. Injuries and cataracts affect the eye itself, while abnormalities such as optic nerve hypoplasia affect the nerve bundle that sends signals from the eye to the back of the brain, which can lead to decreased visual acuity. Cortical blindness results from injuries to the occipital lobe of the brain that prevent the brain from correctly receiving or interpreting signals from the optic nerve.
12357656
Optic nerve


, from which a major relay inputs into the primary visual cortex. The optic nerve is composed of retinal ganglion cell axons and glial cells. Each human optic nerve contains between 770,000 and 1.7 million nerve fibers, which are axons of the retinal ganglion cells of one retina. In the fovea, which has high acuity, these ganglion cells connect to as few as 5 photoreceptor cells; in other areas of retina, they connect to many thousand photoreceptors. The optic nerve leaves the orbit (eye socket) via the optic canal
19187990
Central nervous system


The central nervous system (CNS) is the part of the nervous system consisting of the brain and spinal cord. The CNS is so named because it integrates the received information and coordinates and influences the activity of all parts of the bodies of bilaterally symmetric animals—that is, all multicellular animals except sponges and radially symmetric animals such as jellyfish—and it contains the majority of the nervous system. Many consider the retina and the optic nerve (cranial nerve II), as well as the olfactory nerves (cranial nerve I
7478724
Pseudunela cornuta


, single cerebro-rhinophoral connective. The rhinophoral nerve arises from the rhinophoral ganglion extending to the rhinophore. A small, unpigmented eye is connected by the thin optic nerve to the rhinophoral nerve, slightly anterior to the rhinophoral ganglion. An optic ganglion is attached laterally to each cerebral ganglion and connected to the latter by a thin nerve. The optic ganglion is surrounded by an additional layer of connective tissue shared with the cerebral ganglion. Precerebral anterior accessory ganglia, as described for microhedylacean acochlidians and "Tantulum elegans", are absent
20357473
Parietal eye


vertebrates. Likewise, in the brain of the frog, the diencephalon, from which the pineal stalk arises, appears relatively further forward, as the cerebral hemispheres are smaller but the optic lobes are far more prominent than the human mesencephalon, which is part of the brain stem. In humans the optic tract, commissure, and optic nerve bridge the substantial distance between eyes and diencephalon. Likewise the pineal stalk of "Petromyzon" elongates very considerably during metamorphosis. Crustaceans have a single eye atop the head as a nauplius (first
4754038
Retinal ganglion cell


information from the retina in the form of action potential to several regions in the thalamus, hypothalamus, and mesencephalon, or midbrain. Retinal ganglion cells vary significantly in terms of their size, connections, and responses to visual stimulation but they all share the defining property of having a long axon that extends into the brain. 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
7272646
Artificial organ


tackling the complexity of the artificial connection to the retina, optic nerve, or related brain areas, combined with ongoing advances in computer science, are expected to dramatically improve the performance of this technology. Cardiovascular-related artificial organs are implanted in cases where the heart, its valves, or another part of the circulatory system is in disorder. The artificial heart is typically used to bridge the time to heart transplantation, or to permanently replace the heart in case heart transplantation is impossible. Artificial pacemakers represent another cardiovascular device that can
19520713
Sense


sensory) function of the visual cortex of the brain where patterns and objects in images are recognized and interpreted based on previously learned information. This is called visual memory. The inability to see is called blindness. Blindness may result from damage to the eyeball, especially to the retina, damage to the optic nerve that connects each eye to the brain, and/or from stroke (infarcts in the brain). Temporary or permanent blindness can be caused by poisons or medications. People who are blind from degradation or damage to the visual
11771191
Nervous system


brain and spinal cord. The PNS consists mainly of nerves, which are enclosed bundles of the long fibers or axons, that connect the CNS to every other part of the body. Nerves that transmit signals from the brain are called "motor" or "efferent" nerves, while those nerves that transmit information from the body to the CNS are called "sensory" or "afferent". Spinal nerves serve both functions and are called "mixed" nerves. The PNS is divided into three separate subsystems, the somatic,
2090355
Optic tract


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. 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
9029286
LINGO1


damage within the nerve fibers and loss of myelin within the optic nerve (it normally involves one eye and it's characterized by inflammation). One clinical trial studying the effects on BIIB033 on acute optic neuritis. Throughout the study, optic nerve conduction latency was measured (the time for a signal to travel from the retina to the brain's visual cortex). As about half of patients with optic neuritis will later develop multiple sclerosis, BIIB033 antibody treatment is also being considered for the former disease. It is thought that Anti
14149465
Frog


cord and nerves. Many parts of frog brains correspond with those of humans. It consists of two olfactory lobes, two cerebral hemispheres, a pineal body, two optic lobes, a cerebellum and a medulla oblongata. Muscular coordination and posture are controlled by the cerebellum, and the medulla oblongata regulates respiration, digestion and other automatic functions. The relative size of the cerebrum in frogs is much smaller than it is in humans. Frogs have ten pairs of cranial nerves which pass information from the outside directly to the brain, and
17629319
Posterior ischemic optic neuropathy


vision loss. In the postoperative setting, without gross eye injury, visual loss requires an assessment of the whole visual system for ischemic damage. The optic nerve is not the only tissue of the visual pathway susceptible to decreased blood flow. Decreased oxygenation of the retina or brain could also impair vision. PION is less common than Anterior Ischemic Optic Neuropathy (AION). Blood supply and surrounding anatomy make the anterior and posterior portions of the optic nerve susceptible to different ischemic pressures. The posterior optic nerve receives blood primarily from the
20484731
Accessory nerve


The accessory nerve is a cranial nerve that supplies the sternocleidomastoid and trapezius muscles. It is considered the eleventh of twelve pairs of cranial nerves, or simply cranial nerve XI, as part of it was formerly believed to originate in the brain. The sternocleidomastoid muscle tilts and rotates the head, while the trapezius muscle, connecting to the scapula, acts to shrug the shoulder. Traditional descriptions of the accessory nerve divide it into a spinal part and a cranial part. The cranial component rapidly joins the vagus nerve, and there is
11481870
Optic neuropathy


of injury of the optic nerve is the intracanalicular portion of the nerve. Deceleration injuries from motor vehicle or bicycle accidents account for 17 to 63 percent of cases. Falls are also a common cause, and optic neuropathy most commonly occurs when there is a loss of consciousness associated with multi-system trauma and serious brain injury. In less than three percent of patients, an orbital hemorrhage after an injection behind the eye (retrobulbar block) can cause injury to the optic nerve, but this is readily manageable if it does not
1041637
Adaptationism


not found the solution embodied in cephalopod eyes, where the optic nerve does not interrupt the view. See also: Evolution of the eye. Another example is the cranial nerves in tetrapods. In early vertebrate evolution, sharks, skates, and rays (collectively Chondrichthyes), the cranial nerves run from the part of the brain that interprets sensory information, and radiate out towards the organs that produce those sensations. In tetrapods, however, and mammals in particular, the nerves take an elaborate winding path through the cranium around structures
3637030
Retina


. Light striking the retina initiates a cascade of chemical and electrical events that ultimately trigger nerve impulses that are sent to various visual centres of the brain through the fibres of the optic nerve. Neural signals from the rods and cones undergo processing by other neurons, whose output takes the form of action potentials in retinal ganglion cells whose axons form the optic nerve. Several important features of visual perception can be traced to the retinal encoding and processing of light. In vertebrate embryonic development, the retina and the optic nerve originate as outgrowths
3869617
Visual processing


degree and focused upon the retina. The retina is where a group of light-sensing cells, called photoreceptors are located. There are two types of photoreceptors: rods and cones. Rods are sensitive to dim light and cones are better able to transduce bright light. Photoreceptors connect to bipolar cells, which induce action potentials in retinal ganglion cells. These retinal ganglion cells form a bundle at the optic disc, which is a part of the optic nerve. The two optic nerves from each eye meet at the optic chiasm,
15412659
Optic neuropathy


Optic neuritis is inflammation of the optic nerve, which is associated with swelling and destruction of the myelin sheath covering the optic nerve. Young adults, usually females, are most commonly affected. Symptoms of optic neuritis in the affected eye include pain on eye movement, sudden loss of vision, and decrease in color vision (especially reds). Optic neuritis, when combined with the presence of multiple demyelinating white matter brain lesions on MRI, is suspicious for multiple sclerosis. Several causes and clinical courses are possible for the optic neuritis
1041632
Chiasmal syndrome


also associated with neurofibromatosis type 1. Women are more prone to develop meningiomas. The optic chiasm is formed by the union of the two optic nerves. The nasal fibers of each optic nerve decussate (cross) across the chiasm to the contralateral side while the temporal fibers course posteriorly to form the optic tract on the ipsilateral side. This arrangement allows the left half of the visual field to end up on the right side of the brain and the right half of the visual field to locate to the left side. The optic
16860328
Tetrachromacy


would respond to a new color channel, that is, whether they could handle it separately or just combine it in with an existing channel. Visual information leaves the eye by way of the optic nerve; it is not known whether the optic nerve has the spare capacity to handle a new color channel. A variety of final image processing takes place in the brain; it is not known how the various areas of the brain would respond if presented with a new color channel. Mice, which normally have only two cone pigments
14692482
Contralateral brain


chi). A decussation denotes a crossing of bundles of axonal fibres inside the central nervous system. As a result of such decussations, the efferent connections of the cerebrum to the basal ganglia, the cerebellum and the spine are crossed, and the afferent connections from the spine, the cerebellum and the pons to the thalamus are crossed. As a result, motor, somatosensory, auditory, and visual primary regions in the forebrain represent predominantly the contralateral side of the body. Two of the cranial nerves show chiasmas: the optic
19804199
Human brain


that all information about one side of the visual field passes through tracts in the opposite side of the brain. The nerves reach the brain at the lateral geniculate nucleus, and travel through the optic radiation to reach the visual cortex. Hearing and balance are both generated in the inner ear. The movement of liquids within the inner ear is generated by motion (for balance) and transmitted vibrations generated by the ossicles (for sound). This creates a nerve signal that passes through the vestibulocochlear nerve. From here, it passes
16628483
Talpanas


which the optic nerves pass as they travel from the eyes to the brain). Together, these physical characteristics show that the eyes and optic nerve of this duck were quite reduced in size, and it can be assumed that this species was probably both blind and flightless. However, the maxillo-mandibular foramina (holes through which the trigeminal nerve passes) are extremely large, indicating larger nerves were travelling through it. The authors hypothesize that this blind, or nearly blind, duck would have used tactile and olfactory stimuli (
9033864
Optic nerve hypoplasia


, it is possible to have ONH without any additional issues like SOD. SOD is a condition that can involve multiple problems in the midline structures of the brain, stemming from miswiring of the brain and central nervous system. Besides having small optic nerves, persons with ONH can have agenesis of the corpus callosum, absence of the septum pellucidum, maldevelopment of the anterior and posterior pituitary gland, and anomalies of the hypothalamus. Because of this, all children with ONH are at risk for developmental delays and hormonal deficiencies, regardless of
3344664
Neuropil


factor in differentiating human cognitive capacity from that of other animals. In one study comparing chimpanzee and human frontopolar cortex and the frontoinsular cortex neuropil, it was found that humans exhibit a significantly higher neuropil fraction than the other areas of their brain. This suggests that as we evolved our prefrontal cortex developed denser neuropil which translates to more neural connections. In chimpanzees these prefrontal regions did not display significantly more neuropil. The optic lobe of arthropods and the ganglia of the arthropod brain as well as the ganglia in the ventral nerve cord are
16323049
Cortical stimulation mapping


organization in the primary visual cortex versus that in the retina. Another site of research for a vision prosthesis using cortical stimulation is the optic nerve itself, which contains the nerve fibers responsible for the complete visual field. Research is still ongoing in this area and the small size of the optic nerve and the high density of nerve fibers are continuing challenges to this approach Cortical stimulation mapping (CSM) is considered the gold standard for mapping functional regions of the brain to create a presurgical plan that maximizes the patient's functional outcome.
16905894
Pathology of multiple sclerosis


synaptic degeneration as a contributor to chronic axon damage in the optic nerve and retina Nevertheless, the authors of the paper were unable to identify whether the degeneration condition spreads from the anterior part or from the rear. The optic radiation (OR), which is a set of axons that lead to the visual cortex, is more similar to the rest of the brain because it contains myelin. It is also damaged. In this area NAWM areas (see below) appear. The optic radiation damage is composed by two factors:
3581444
Retina


of the developing brain, specifically the embryonic diencephalon; thus, the retina is considered part of the central nervous system (CNS) and is actually brain tissue. It is the only part of the CNS that can be visualized non-invasively. The vertebrate retina is "inverted" in the sense that the light sensing cells are in back of the retina, so that light has to pass through layers of neurons and capillaries before it reaches the rods and cones. The ganglion cells, whose axons form the optic nerve,
3869618
Chiasmal syndrome


small series of optic nerve sections at the optic nerve-chiasm junction. Several important structures are located adjacent to the optic chiasm. The supraclinoid branches of the internal carotid artery flank the chiasm. The cavernous sinuses are lateral and inferior to the chiasm. The frontal lobe of the brain lies above. The pituitary gland sits below in the sella turcica. The sella turcica is bound in front by the tuberculum sellae and behind by the dorsum sellae. Behind the chiasm lies the floor of the third ventricle. Lee has divided optic
16860332
Brain


to all of the above, the brain and spinal cord contain extensive circuitry to control the autonomic nervous system, which works by secreting hormones and by modulating the "smooth" muscles of the gut. Many animals alternate between sleeping and waking in a daily cycle. Arousal and alertness are also modulated on a finer time scale by a network of brain areas. A key component of the arousal system is the suprachiasmatic nucleus (SCN), a tiny part of the hypothalamus located directly above the point at which the optic nerves from
3380201
Karl Wallinger


for the band, he felt unwell, and asked his friends to call an ambulance. He was taken to the hospital and was diagnosed with a brain aneurysm. This led him to require surgery wherein the surgeons had to block a nerve near the optic nerve. Despite what would appear a full recovery, he lost his peripheral vision on the left side of both eyes. Although the aneurysm meant that he had to suspend all work for nearly five years, he eventually resumed touring in 2006. BBC Radio 4 Extra – Loose
13946783
Pathology of multiple sclerosis


disease activity show high levels of "Lateral Olfactory Tract Usher Substance" (LOTUS) The eye's retina in MS is also damage. Given that retina cells have no myelin, damage must be different from the autoimmune attack of the brain. The underlying condition in the retina produces pure neurodegeneration. The retina and the optic nerve originate as outgrowths of the brain during embryonic development, so they are considered part of the central nervous system (CNS). It is the only part of the CNS that can be imaged non-
3581441
Retina


ganglion cells; and transmission along the optic nerve. At each synaptic stage there are also laterally connecting horizontal and amacrine cells. The optic nerve is a central tract of many axons of ganglion cells connecting primarily to the lateral geniculate body, a visual relay station in the diencephalon (the rear of the forebrain). It also projects to the superior colliculus, the suprachiasmatic nucleus, and the nucleus of the optic tract. It passes through the other layers, creating the optic disc in primates. Additional structures, not directly associated
3869624
Orbit (anatomy)


potential pathways for cancer and infections of the orbit to spread into the brain or other deep facial structures. The optic canal contains the optic nerve (cranial nerve II) and the ophthalmic artery, and sits at the junction of the sphenoid sinus with the ethmoid air cells, superomedial and posterior to structures at the orbital apex. It provides a pathway between the orbital contents and the middle cranial fossa. The superior orbital fissure lies just lateral and inferior to the optic canal, and is formed at the junction of the lesser and
13135552
Persistence of vision


an important factor in the illusion of moving pictures in cinema and related optical toys, but not as its sole principle. Early descriptions of the illusion often attributed the effect purely to imperfections of the eye, particularly of the retina. Nerves and parts of the brain later became part of explanations. Sensory memory has been cited as a cause. Some natural phenomena and the principles of some optical toys have been attributed to the persistence of vision effect. Patrick d'Arcy recognised the effect in "the luminous ring that we see by turning
3721678
Psycholinguistics


, or phoneme encoding, and usually not the first step of semantic encoding. This can be credited to how a speaker is still conjuring the idea of what to say, and unless he changes his mind, can not be mistaken in what he wanted to say. Until the recent advent of non-invasive medical techniques, brain surgery was the preferred way for language researchers to discover how language works in the brain. For example, severing the corpus callosum (the bundle of nerves that connects the two hemispheres of the brain
1387959
Suboesophageal ganglion


The suboesophageal ganglion (acronym: SOG; synonym: "subesophageal ganglion") of arthropods and in particular insects is part of the arthropod central nervous system (CNS). As indicated by its name, it is located "below the" "oesophagus", inside the head. As part of the ventral nerve cord, it is connected (via pairs of connections) to the brain (or supraoesophageal ganglion) and to the first thoracic ganglion (or protothoracic ganglion). Its nerves innervate the sensory organs and muscles of
12919562
Nerve


electrical. Nerves can be categorized into two groups based on function: The nervous system is the part of an animal that coordinates its actions by transmitting signals to and from different parts of its body. In vertebrates it consists of two main parts, the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS consists of the brain and spinal cord. The PNS consists mainly of nerves, which are enclosed bundles of the long fibers or axons, that connect the CNS to every other part of
1710567
Trigeminal nerve


in the cerebral cortex. Each pathway consists of three bundles of nerve fibers connected in series: The secondary neurons in each pathway decussate (cross the spinal cord or brainstem), because the spinal cord develops in segments. Decussated fibers later reach and connect these segments with the higher centers. The optic chiasm is the primary cause of decussation; nasal fibers of the optic nerve cross (so each cerebral hemisphere receives contralateral—opposite—vision) to keep the interneuronal connections responsible for processing information short. All sensory and motor pathways
11481323
Nervous system of gastropods


tentacles, and other sensory organs in the head. Beneath the oesophagus, at the forward part of the foot, lie the pedal ganglia. As their name implies, these supply nerves to the foot muscles. The third pair of ganglia within the brain lie slightly behind and below the cerebral ganglia. These are the pleural ganglia, and supply nerves to the mantle cavity. Bundles of nerves connect the cerebral, pedal, and pleural ganglia together, as well as running above and below the oesophagus to connect the right and left
21791663
Cranial nerves


(I) and Optic (II) nerves to be brain tracts, rather than cranial nerves. Further, the very small terminal nerve (nerve N or O) exists in humans but may not be functional. In other animals, it appears to be important to sexual receptivity based on perceptions of phermones Cranial nerves are also present in other vertebrates. Other amniotes (non-amphibian tetrapods) have cranial nerves similar to those of humans. In anamniotes (fishes and amphibians), the accessory nerve (XI) and hypoglossal
16439956
Colin Blakemore


, as other parts of the brain take over the function of the damaged part. Blakemore's recent work has emphasized the variety of molecular mechanisms that contribute to plasticity and has identified some of the genes involved in enabling nerve cells to modify their connections in response to the flow of nerve impulses through them. He summarised research on brain plasticity in his 2005 Harveian Lecture to the Royal College of Physicians and explored the role of plasticity in human cultural evolution in his 2010 Ferrier Lecture at the Royal Society. He is currently serving on
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Adam (Buffy the Vampire Slayer)


" When he auditioned, Hertzberg had no idea what Adam would look like in full costume and make-up. "Buffy" used a company named Optic Nerve to build the materials to make Hertzberg look like a demonoid. Almost immediately after Hertzberg got the part, Optic Nerve sketched and sculpted Adam's appearance. They had Hertzberg come in to have molds made for prosthetic parts to fit his head and face, arms, chest, and legs, then he was fitted for contact lenses. They also created separate hands and
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Short ciliary nerves


The branches of the ciliary ganglion are the short ciliary nerves. These are delicate filaments, from six to ten in number, which arise from the forepart of the ganglion in two bundles connected with its superior and inferior angles; the lower bundle is the larger. They run forward with the ciliary arteries in a wavy course, one set above and the other below the optic nerve, and are accompanied by the long ciliary nerves from the nasociliary. They pierce the sclera at the back part of the bulb of the eye,
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Aspidogastrea


have a nervous system of extraordinary complexity, greater than that of related free-living forms, and a great number of sensory receptors of many different types. The nervous system is of great complexity, consisting of a great number of longitudinal nerves (connectives) connected by circular commissures. The brain (cerebral commissure) is located dorsally, in the anterior part of the body, the eyes dorsally attached to it. A nerve from the main connective enters the pharynx and also supplies the intestine. Posteriorly, the main connective enters
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Cranial nerves


however, emerge from the central nervous system above this level. Each cranial nerve is paired and is present on both sides. Depending on definition in humans there are twelve or thirteen cranial nerves pairs, which are assigned Roman numerals I–XII, sometimes also including cranial nerve zero. The numbering of the cranial nerves is based on the order in which they emerge from the brain, front to back (brainstem). The terminal nerves (0), olfactory nerves (I) and optic nerves (II) emerge from
16439923
Albert Einstein's brain


's left brain may have had stronger nerve cell connections between the hippocampus and another part of the brain called the neocortex than his right. The neocortex is "where detailed, logical, analytical and innovative thinking takes place," Zaidel noted in a prepared statement." A study published in the journal "Brain" in September 2013 analyzed Einstein's corpus callosum - a large bundle of fibers that connects the two cerebral hemispheres and facilitates interhemispheric communication in the brain - using a novel technique that allowed for a higher resolution measurement of
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Optic nerve


of twelve paired cranial nerves but is technically part of the central nervous system, rather than the peripheral nervous system because it is derived from an out-pouching of the diencephalon (optic stalks) during embryonic development. As a consequence, the fibers of the optic nerve are covered with myelin produced by oligodendrocytes, rather than Schwann cells of the peripheral nervous system, and are encased within the meninges. Peripheral neuropathies like Guillain–Barré syndrome do not affect the optic nerve. However, most typically the optic nerve is grouped with
19187988
Color vision


axis from blue-green to magenta. Small bistratified retinal ganglion cells oppose input from the S cones to input from the L and M cones. This is often thought to correspond to blue–yellow opponency, but actually runs along a color axis from yellow-green to violet. Visual information is then sent to the brain from retinal ganglion cells via the optic nerve to the optic chiasma: a point where the two optic nerves meet and information from the temporal (contralateral) visual field crosses to the other side of the
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Visual acuity


over which an animal is highly sensitive to such visual deprivation is referred to as the critical period. The eye is connected to the visual cortex by the optic nerve coming out of the back of the eye. The two optic nerves come together behind the eyes at the optic chiasm, where about half of the fibers from each eye cross over to the opposite side and join fibers from the other eye representing the corresponding visual field, the combined nerve fibers from both eyes forming the optic tract. This ultimately forms the physiological basis
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Anatomical terms of neuroanatomy


in which the nerve fibre conducts signals. Specific terms are also used to describe the route of a nerve or nerve fibre: A "chiasm" () is used to describe an X-shaped crossing of nerve fibres between the cerebral hemispheres. The major example in the human brain is the Optic chiasm. The main difference between such a chiasm and a decussation is that not all nerve fibres entering the chiasm cross over. A "commissure" is a group of nerve fibres crossing the sagittal plane mainly parallel to the lateral
19005231
Scientific Revolution


connections with the stomach, the spleen and the colon; gave the first correct views of the structure of the pylorus; observed the small size of the caecal appendix in man; gave the first good account of the mediastinum and pleura and the fullest description of the anatomy of the brain yet advanced. He did not understand the inferior recesses; and his account of the nerves is confused by regarding the optic as the first pair, the third as the fifth and the fifth as the seventh. Further groundbreaking work was carried out
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Visual acuity


of binocular vision. The tracts project to a relay station in the midbrain called the lateral geniculate nucleus, part of the thalamus, and then to the visual cortex along a collection of nerve fibers called the optic radiation. Any pathological process in the visual system, even in older humans beyond the critical period, will often cause decreases in visual acuity. Thus measuring visual acuity is a simple test in accessing the health of the eyes, the visual brain, or pathway to the brain. Any relatively sudden decrease in visual acuity
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Pupillary light reflex


(cranial nerve #3), to the ciliary sphincter, the muscular structure within the iris. The diagram may assist in localizing lesion within the pupillary reflex system by process of elimination, using light reflex testing results obtained by clinical examination. Pupillary light reflex provides a useful diagnostic tool for testing the integrity of the sensory and motor functions of the eye. Emergency physicians routinely test pupillary light reflex to assess brain stem function. Abnormal pupillary reflex can be caused by optic nerve damage, oculomotor nerve damage, brain stem lesion (
6256163
Book of Optics


the eye are the aqueous humor in front of the crystalline humor and the vitreous humor at the back. These, however, do not play as critical of a role in vision as the crystalline humor. The crystalline humor transmits the image it perceives to the brain through an optic nerve. The "Book of Optics" was most strongly influenced by Ptolemy's "Optics", while the description of the anatomy and physiology of the eye was based upon an account by Galen. The "Book of Optics" was translated into
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Orbit (anatomy)


vessel along the superior margin of the orbital canal that drains deoxygenated blood from surrounding musculature. The ophthalmic artery is a crucial structure in the orbit, as it is often the only source of collateral blood to the brain in cases of large internal carotid infarcts, as it is a collateral pathway to the circle of Willis. In addition, there is the optic canal, which contains the optic nerve, or cranial nerve II, and is formed entirely by the lesser wing of the sphenoid, separated from the supraorbital fissure by the
13135559
Neuroprosthetics


a multilayer neural structure about 200 um thick that lines the back of the eye. The processed signal is sent to the brain through the optical nerve. If any part of this pathway is damaged blindness can occur. Blindness can result from damage to the optical pathway (cornea, aqueous humor, crystalline lens, and vitreous). This can happen as a result of accident or disease. The two most common retinal degenerative diseases that result in blindness secondary to photoreceptor loss is age related macular degeneration (AMD) and retinitis pigmentosa
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Brain


the Hippocratic Corpus, came down unequivocally in favor of the brain, writing: The Roman physician Galen also argued for the importance of the brain, and theorized in some depth about how it might work. Galen traced out the anatomical relationships among brain, nerves, and muscles, demonstrating that all muscles in the body are connected to the brain through a branching network of nerves. He postulated that nerves activate muscles mechanically by carrying a mysterious substance he called "pneumata psychikon", usually translated as "animal spirits". Galen
3380225
George Henry Lewes


by physiologists, of which the most valuable is that now known as the doctrine of the functional indifference of the nerves – that what were known as the specific energies of the optic, auditory and other nerves are simply differences in their mode of action due to the differences of the peripheral structures or sense-organs with which they are connected. This idea was subsequently proposed independently by Wundt. In 1865, when "The Fortnightly Review" began publication, Lewes became its editor, but he retained the post for less than two
2160701
Superior colliculus


structure in the brain. (See the adjoining drawing of a codfish brain.) In amphibians, reptiles, and especially birds it is also a very significant component, but in mammals it is dwarfed by the massive expansion of the cerebral cortex. In snakes that can detect infrared radiation, such as pythons and pit vipers, the initial neural input is through the trigeminal nerve instead of the optic tract. The rest of the processing is similar to that of the visual sense and, thus, involves the optic tectum. The
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Onychophora


behind each antenna. This consists of a chitinous ball lens, a cornea and a retina and is connected to the centre of the brain via an optic nerve. The retina comprises numerous pigment cells and photoreceptors; the latter are easily modified flagellated cells, whose flagellum membranes carry a photosensitive pigment on their surface. The rhabdomeric eyes of the Onychophora are thought to be homologous with the median ocelli of arthropods; this would imply that the last common ancestor of arthropods bore only median ocelli. However, the innervation shows that the homology
20683012
Wolfram syndrome


acronym DIDMOAD. This syndrome is characterised by childhood-onset diabetes mellitus (DM), which results from the improper control of glucose due to the lack of insulin; a gradual loss of vision caused by optic atrophy (OA), in which the nerve that connects the eye to the brain wastes away; and deafness (D). This syndrome can sometimes cause diabetes insipidus (DI), a condition in which the kidneys cannot conserve water. Other complications that affect the bladder and nervous system may also occur.
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Nerve


organ. Other terms relate to whether the nerve affects the same side ("ipsilateral") or opposite side ("contralateral") of the body, to the part of the brain that supplies it. Nerve growth normally ends in adolescence, but can be re-stimulated with a molecular mechanism known as "Notch signaling". If the axons of a neuron are damaged, as long as the cell body of the neuron is not damaged, the axons would regenerate and remake the synaptic connections with neurons with the help
1710564
Ischemic optic neuropathy


Ischemic optic neuropathy (ION) is the loss of structure and function of a portion of the optic nerve due to obstruction of blood flow to the nerve (i.e. ischemia). Ischemic forms of optic neuropathy are typically classified as either anterior ischemic optic neuropathy or posterior ischemic optic neuropathy according to the part of the optic nerve that is affected. People affected will often complain of a loss of visual acuity and a visual field, the latter of which is usually in the superior or inferior field. When ION occurs in patients below
12552576
Form perception


blank areas with the surviving illuminant-discounted signals. In addition to photoreceptors, the eye requires a properly functioning lens, retina, and an undamaged optic nerve to recognize form. Light travels through the lens, hits the retina, activates the appropriate photoreceptors, depending on available light, which convert the light into an electrical signal that travels along the optic nerve to the lateral geniculate nucleus of the thalamus and then to the primary visual cortex. In the cortex, the adult brain processes information such as lines, orientation, and
19399757
Optic Nerve (comics)


, originally published in Optic Nerve #5, which chronicles a promising young author struggling to write a sophomore novel. In the wake of his writer's block, he becomes obsessed with re-connecting with his high school crush, despite currently being in a relationship. His feelings are further complicated when he begins spending time with his crush's teenage sister. "Hawaiian Getaway", originally published in Optic Nerve #6, is the story of Hilary Chan's evolving circumstances when she finds herself unemployed and with no meaningful social
1242105
Anatomy


convey neural impulses. It was Herophilus who made the point that damage to motor nerves induced paralysis. Herophilus named the meninges and ventricles in the brain, appreciated the division between cerebellum and cerebrum and recognized that the brain was the "seat of intellect" and not a "cooling chamber" as propounded by Aristotle Herophilus is also credited with describing the optic, oculomotor, motor division of the trigeminal, facial, vestibulocochlear and hypoglossal nerves. Great feats were made during the third century in both the digestive and reproductive systems. Herophilus
71974
Human body


human body has four limbs (two arms and two legs), a head and a neck which connect to the torso. The body's shape is determined by a strong skeleton made of bone and cartilage, surrounded by fat, muscle, connective tissue, organs, and other structures. The spine at the back of the skeleton contains the flexible vertebral column which surrounds the spinal cord, which is a collection of nerve fibres connecting the brain to the rest of the body. Nerves connect the spinal cord and brain to the
9395832
Axonal transport


in the optic nerve and in the brain. Transport in both hippocampal projections and in the optic nerve also depends on APP. Transport from hippocampus to forebrain is decreased in aging and destination is altered by the presence of Alzheimer's disease plaques. Retrograde transport shuttles molecules/organelles away from axon termini toward the cell body. Retrograde axonal transport is mediated by cytoplasmic dynein, and is used for example to send chemical messages and endocytosis products headed to endolysosomes from the axon back to the cell. Operating at average "in vivo"
11529962
Scotoma


a visual field may go unnoticed by the bearer because of the normal reduced optical resolution in the peripheral visual field. Common causes of scotomata include demyelinating disease such as multiple sclerosis (retrobulbar neuritis), damage to nerve fiber layer in the retina (seen as cotton wool spots) due to hypertension, toxic substances such as methyl alcohol, ethambutol and quinine, nutritional deficiencies, vascular blockages either in the retina or in the optic nerve, stroke or other brain injury, and macular degeneration, often associated with aging. Scintillating scotoma
12030937
Role of microglia in disease


. Also a new software to automatize the count of microglial cells in the retina has been published. However, depletion of microglia from the retina and optic nerve does not affect the degeneration process of retinal ganglion cells after acute injury of the optic nerve. Thus, it remains to be studied whether microglia play a functional role in the degeneration process in glaucoma. Gliomas are complex brain tumors composed of heterogeneous populations of neoplastic as well as non-neoplastic cells. Not only tumor cells, but also non-tumor cells of the
3749491
Free-electron laser


a free-electron laser. Starting in 1999, Copeland and Konrad performed three surgeries in which they resected meningioma brain tumors. Beginning in 2000, Joos and Mawn performed five surgeries that cut a window in the sheath of the optic nerve, to test the efficacy for optic nerve sheath fenestration. These eight surgeries produced results consistent with the standard of care and with the added benefit of minimal collateral damage. A review of FELs for medical uses is given in the 1st edition of Tunable Laser Applications. Several small, clinical lasers
5358461
Polio


2 percent of cases of paralytic polio, bulbar polio occurs when poliovirus invades and destroys nerves within the bulbar region of the brain stem. The bulbar region is a white matter pathway that connects the cerebral cortex to the brain stem. The destruction of these nerves weakens the muscles supplied by the cranial nerves, producing symptoms of encephalitis, and causes difficulty breathing, speaking and swallowing. Critical nerves affected are the glossopharyngeal nerve (which partially controls swallowing and functions in the throat, tongue movement, and taste), the vagus nerve
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