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Commissure Of Gudden
The ventral supraoptic decussation is the crossover (decussation) point for signals from the left and right eye, en route respectively to the right and left sides of the visual cortex. Occupying the posterior part of the commissure of the optic chiasma is a strand of fibers, the Ventral supraoptic decussation (commissure of Gudden, Gudden's inferior commissure), which is not derived from the optic nerves In neuroanatomy, the optic nerve, also known as the second cranial nerve, cranial nerve II, or simply 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 ...; it forms a connecting link between the medial geniculate bodies. References External links * Visual system {{Neuroanatomy-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optic Nerve
In neuroanatomy, the optic nerve, also known as the second cranial nerve, cranial nerve II, or simply CN II, is a paired cranial nerve that transmits visual system, 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 area, pretectal nuclei, and superior colliculus. Structure The optic nerve has been classified as the second of twelve paired cranial nerves, but it 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 per ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optic Tract
In neuroanatomy, the optic tract () 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 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 ri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Decussation
Decussation is used in biological contexts to describe a crossing (due to the shape of the Roman numeral for ten, an uppercase 'X' (), ). In Latin anatomical terms, the form is used, e.g. . Similarly, the anatomical term chiasma is named after the Greek uppercase 'Χ' (chi). Whereas a decussation refers to a crossing within the central nervous system, various kinds of crossings in the peripheral nervous system are called chiasma. Examples include: * In the brain, where nerve fibers obliquely cross from one lateral side of the brain to the other, that is to say they cross at a level other than their origin. See for examples Decussation of pyramids and sensory decussation. In neuroanatomy, the term ''chiasma'' is reserved for crossing of- or within nerves such as in the optic chiasm. * In botanical leaf taxology, the word ''decussate'' describes an opposite pattern of leaves which has successive pairs at right angles to each other (i.e. rotated 90 degrees along the stem when ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Commissure
A commissure () is the location at which two objects abut or are joined. The term is used especially in the fields of anatomy and biology. * The most common usage of the term refers to the brain's commissures, of which there are five. Such a commissure is a bundle of commissural fibers as a tract that crosses the midline at its level of origin or entry (as opposed to a decussation of fibers that cross obliquely). The five are the anterior commissure, posterior commissure, corpus callosum, commissure of fornix (hippocampal commissure), and habenular commissure. They consist of fibre tracts that connect the two cerebral hemispheres and span the longitudinal fissure. In the spinal cord there are the anterior white commissure, and the gray commissure. ''Commissural neurons'' refer to neuronal cells that grow their axons across the midline of the nervous system within the brain and the spinal cord. * ''Commissure'' also often refers to cardiac anatomy of heart valves. In the heart, a co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optic Chiasma
In neuroanatomy, the optic chiasm, or optic chiasma (; , ), 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. The optic chiasm is found in all vertebrates, although in cyclostomes (lampreys and hagfishes), it is located within the brain. This article is about the optic chiasm of vertebrates, which is the best known nerve chiasm, but not every chiasm denotes a crossing of the body midline (e.g., in some invertebrates, see Chiasm (anatomy)). A midline crossing of nerves inside the brain is called a decussation (see Definition of types of crossings). Structure For the different types of optic chiasm, see In all vertebrates, the optic nerves of the left and the right eye meet in the body midline, ventral to the brain. In many vertebrates the left optic nerve crosses over the right one without fusing with it. In vertebrates with a large overlap of the visual fields of the two eyes, i.e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optic Nerves
In neuroanatomy, the optic nerve, also known as the second cranial nerve, cranial nerve II, or simply 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. Structure The optic nerve has been classified as the second of twelve paired cranial nerves, but it 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Medial Geniculate Bodies
The medial geniculate nucleus (MGN) or medial geniculate body (MGB) is part of the auditory thalamus and represents the thalamic relay between the inferior colliculus (IC) and the auditory cortex (AC). It is made up of a number of sub-nuclei that are distinguished by their neuronal morphology and density, by their afferent and efferent connections, and by the coding properties of their neurons. It is thought that the MGN influences the direction and maintenance of attention. Divisions The MGN has three major divisions; ventral (VMGN), dorsal (DMGN) and medial (MMGN). Whilst the VMGN is specific to auditory information processing, the DMGN and MMGN also receive information from non-auditory pathways. Ventral subnucleus Cell types There are two main cell types in the ventral subnucleus of the medial geniculate body (VMGN): * Thalamocortical relay cells (or principal neurons): The dendritic input to these cells comes from two sets of dendritic trees oriented on opposite poles of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
