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Encyclopedia > Corticospinal tract
Brain: Corticospinal tract
Deep dissection of brain-stem. Lateral view. ("pyramidal tract" visible in red, and "pyramidal decussation" labeled at lower right.)
Diagram of the principal fasciculi of the spinal cord.
Latin '
Gray's subject #185 759
Part of
Components
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Acronym(s) {{{Acronym}}}
NeuroNames ancil-373
MeSH A08.186.854.633
Dorlands/Elsevier {{{DorlandsPre}}}/{{{DorlandsSuf}}}

The corticospinal or pyramidal tract is a massive collection of axons that travel between the cerebral cortex of the brain and the spinal cord. Image File history File links Download high resolution version (533x800, 169 KB) Summary Licensing File links The following pages link to this file: Wikipedia:Grays Anatomy images with missing articles 14 Corticospinal tract List of images in Grays Anatomy: IX. Neurology ... Image File history File links Gray672. ... Latin is an ancient Indo-European language originally spoken in the region around Rome called Latium. ... NeuroNames is a system of nomenclature for the brain and related structures. ... Medical Subject Headings (MeSH) is a huge controlled vocabulary (or metadata system) for the purpose of indexing journal articles and books in the life sciences. ... Elseviers logo Elsevier, the worlds largest publisher of medical and scientific literature, forms part of the Reed Elsevier group. ... An axon, or nerve fiber, is a long slender projection of a nerve cell, or neuron, that conducts electrical impulses away from the neurons cell body or soma. ... Location of the cerebral cortex Slice of the cerebral cortex, ca. ... Comparative brain sizes In animals, the brain, or encephalon (Greek for in the head), is the control center of the central nervous system. ... Cross-section through cervical spinal cord. ...


The corticospinal tract contains exclusively motor axons. It actually consists of two separate tracts in the spinal cord: the lateral corticospinal tract and the medial corticospinal tract. An understanding of these tracts leads to an understanding of why one side of the body is controlled by the opposite side of the brain. An axon, or nerve fiber, is a long slender projection of a nerve cell, or neuron, that conducts electrical impulses away from the neurons cell body or soma. ... The corticospinal or pyramidal tract is a massive collection of axons that travel between the cerebral cortex of the brain and the spinal cord. ...

Contents


The motor pathway

The corticospinal tract originates in the giant pyramidal neurons (Betz cells) of the motor cortex. The neuronal cell bodies in the motor cortex send long axons to the motor cranial nerve nuclei mainly of the contralateral side of the midbrain (cortico-mesencephalic tract), pons (cortico-pontine tract), medulla oblongata (cortico-bulbar tract); the bulk of these fibers, however, extend all the way down to the spinal cord (corticospinal tract). Most of the cortico-spinal fibers (about 85%) cross over to the contralateral side in the medulla oblongata (pyramidal decussation). Those that do cross in the medulla oblongata travel in the lateral corticospinal tract. The remainder of them (15%) cross over at the level that they exit the spinal cord, and these travel in the medial corticospinal tract. Despite which of these two tracts it travels in, the axon of a neuron which is part of this tract will synapse with another neuron in the ventral horn. This ventral horn neuron is considered a second-order neuron in this pathway, but is not part of the corticospinal tract itself and lies outside the central nervous system. Drawing by Santiago Ramón y Cajal of cells in the pigeon cerebellum. ... // Early work on motor cortex function Back in the 1940s, Canadian neurosurgeon Wilder Penfield wanted to know which bits of epileptics brains he could suck out without them noticing. ... Drawing by Santiago Ramón y Cajal of cells in the pigeon cerebellum. ... Cranial nerves are nerves which start directly from the brainstem instead of the spinal cord. ... In biological anatomy, the mesencephalon (or midbrain) is the middle of three vesicles that arise from the neural tube that forms the brain of developing animals. ... Position of the pons in the human brain The pons (sometimes pons Varolii after Costanzo Varolio) is a knob on the brain stem. ... Position of medulla oblangata in the human brain The medulla oblongata is the lower portion of the brainstem. ... Cross-section through cervical spinal cord. ... Position of medulla oblangata in the human brain The medulla oblongata is the lower portion of the brainstem. ... The corticospinal or pyramidal tract is a massive collection of axons that travel between the cerebral cortex of the brain and the spinal cord. ... Cross-section through cervical spinal cord. ... An axon, or nerve fiber, is a long slender projection of a nerve cell, or neuron, that conducts electrical impulses away from the neurons cell body or soma. ... Illustration of the major elements in a prototypical synapse. ... The anterior horn is the anterior division of the lateral ventricle of the brain. ... A diagram showing the CNS: 1. ...


There is a precise somatotopic representation of the different body parts in the primary motor cortex, with the leg area located medially (close to the midline), and the head and face area located laterally on the convex side of the cerebral hemisphere (motor homunculus). The arm and hand motor area is the largest and occupies the part of precentral gyrus, located inbetween the leg and face area. Hartsoekers homunculus The concept of a homunculus (Latin for little man, sometimes spelled homonculus, plural homunculi) is often used to illustrate the functioning of a system. ...


The motor axons move closer together as they travel down through the cerebral white matter, and form part of the posterior limb of the internal capsule. White matter is one of the two main solid components of the central nervous system. ... The internal capsule is an area of white matter in the brain that separates the caudate nucleus and the thalamus from the lenticular nucleus. ...


The motor fibers continue down into the brainstem. The bundle of corticospinal axons is visible as two column-like structures ("pyramids") on the ventral surface of medulla oblongata - this is where the name pyramidal tract comes from. The brain stem is the stalk of the brain below the cerebral hemispheres. ... Position of medulla oblangata in the human brain The medulla oblongata is the lower portion of the brainstem. ...


After the decussation, the axons travel down the spinal cord as the lateral corticospinal tract. Fibers that do not cross over in the medulla oblongata travel down the separate ventral corticospinal tract, and most of them cross over to the contralateral side in the spinal cord, shortly before reaching the lower motor neurons. Cross-section through cervical spinal cord. ... Position of medulla oblangata in the human brain The medulla oblongata is the lower portion of the brainstem. ... Cross-section through cervical spinal cord. ... Lower motor neurons are the motoneurons connecting the spinal cord to the muscle fibers, bringing the nerve signals from the upper motor neurons out the spine to the muscles. ...


The motor neuron cell bodies in the motor cortex, together with their axons that travel down the brain stem and spinal cord, are referred to as upper motor neuron. In the spinal cord, these axons connect (most of them via interneurons, but to a lesser extent also via direct synapses) with the lower motor neurons (LMNs), located in the ventral horn of the spinal cord. In the brain stem, the lower motor neurons are located in the motor cranial nerve nuclei (occulomotor, trochlear, motor nucleus of the trigeminal nerve, abducens, facial, accessory, hypoglossal). The lower motor neuron axons leave the brain stem via motor cranial nerves and the spinal cord via anterior roots of the spinal nerves respectively, end-up at the neuromuscular plate and provide motor innervation for voluntary muscles. // Early work on motor cortex function Back in the 1940s, Canadian neurosurgeon Wilder Penfield wanted to know which bits of epileptics brains he could suck out without them noticing. ... The term brain stem (truncus encephali is a Latin synonym) refers to a composite substructure of the brain. ... Cross-section through cervical spinal cord. ... Upper motor neurons, or Betz cells, are motoneurons located in the primary motor cortex. ... An interneuron is a neuron that communicates only to other neurons. ... Illustration of the major elements in a prototypical synapse. ... Lower motor neurons are the motoneurons connecting the spinal cord to the muscle fibers, bringing the nerve signals from the upper motor neurons out the spine to the muscles. ... The term brain stem (truncus encephali is a Latin synonym) refers to a composite substructure of the brain. ... Lower motor neurons are the motoneurons connecting the spinal cord to the muscle fibers, bringing the nerve signals from the upper motor neurons out the spine to the muscles. ... Cranial nerves are nerves which start directly from the brainstem instead of the spinal cord. ... The oculomotor nerve is the third of twelve paired cranial nerves. ... The fourth of twelve cranial nerves, the trochlear nerve controls the function of the superior oblique muscle, which rotates the eye towards the nose and also moves the eye downward. ... The trigeminal nerve is the fifth (V) cranial nerve, and carries sensory information from most of the face, as well as motor supply to the muscles of mastication (the muscles enabling chewing), tensor tympani (in the middle ear) and other muscles in the floor of the mouth, such as the... The sixth out of twelve cranial nerves, the abducens nerve controls the lateral rectus muscle - this means that the action of this nerve controls each eyes ability to look laterally (away from the midline). ... The word facial is concerning anything related to the face. ... The word Accessory can refer to: A legal term for a person who assists a criminal but is not present at the crime; A band consisting of Dirk Steyer and Ivo Lottig; A Fashion accessory, i. ... The hypoglossal nerve is the twelfth cranial nerve. ... Lower motor neurons are the motoneurons connecting the spinal cord to the muscle fibers, bringing the nerve signals from the upper motor neurons out the spine to the muscles. ... An axon, or nerve fiber, is a long slender projection of a nerve cell, or neuron, which conducts electrical impulses away from the neurons cell body or soma. ... The term brain stem (truncus encephali is a Latin synonym) refers to a composite substructure of the brain. ... Cross-section through cervical spinal cord. ... The term spinal nerve generally refers to the mixed spinal nerve, which is formed from the dorsal and ventral roots that come out of the spinal cord. ...


Sensory pathways

The spinothalamic tract is the sensory pathway in the body that transmits pain, temperature, itch and crude touch. ... The spinocerebellar tract is a set of axonal fibers originating in the spinal cord and terminating in the cerebellum. ... The visual system is the part of the nervous system which allows organisms to see. ... The olfactory system is the sensory system used for olfaction. ... The posterior column-medial lemniscus pathway (called the dorsal column in non-humans) is the sensory pathway responsible for transmitting discriminative sensation from the skin to the thalamus, and on to the cerebral cortex. ...

Corticospinal tract damage

see upper motor neuron. Upper motor neurons, or Betz cells, are motoneurons located in the primary motor cortex. ...


Extrapyramidal motor pathways

These are motor pathways that lie outside the corticospinal tract and are beyond voluntary control. Their main function is to support voluntary movement and help control posture and muscle tone. See extrapyramidal motor system. In human anatomy, the extrapyramidal system is a neural network located in the brain that is part of the motor system involved in the coordination of movement. ...


External links

Telencephalon (cerebrum, cerebral cortex, cerebral hemispheres) - edit

primary sulci/fissures: medial longitudinal, lateral, central, parietoöccipital, calcarine, cingulate GPnotebook is a British medical database for general practitioners (GPs. ... The University of California, Davis, commonly known as UC Davis, is one of the ten University of California campuses. ... The telencephalon (te-len-seff-a-lon) is the technical name for a large region within the brain which is attributed many functions, which some groups would class as unique features which make humans stand out from other species. ... Location of the cerebral cortex Slice of the cerebral cortex, ca. ... Human brain viewed from above, showing cerebral hemispheres. ... A sulcus (pl. ... The medial longitudinal fissure is the deep groove which separates the two hemispheres of the vertebrate brain. ... Lateral sulcus The lateral sulcus (also called Sylvian fissure or lateral fissure) is one of the most prominent structures of the human brain. ... Central sulcus of the human brain. ... Only a small part of the Parieto̦ccipital Fissure (or parieto-occipital sulcus) is seen on the lateral surface of the hemisphere, its chief part being on the medial surface. ... The calcarine fissure (or calcarine sulcus) is on the medial surface of the hemisphere. ... Categories: Stub | Cerebrum ...


frontal lobe: precentral gyrus (primary motor cortex, 4), precentral sulcus, superior frontal gyrus (6, 8), middle frontal gyrus (46), inferior frontal gyrus (Broca's area, 44-pars opercularis, 45-pars triangularis), prefrontal cortex (orbitofrontal cortex, 9, 10, 11, 12, 47) The frontal lobe is an area in the brain of vertebrates. ... The precentral gyrus (a. ... The primary motor area is a group of networked cells in mammalian brains that controls movements of specific body parts associated with cell groups in that area of the brain. ... Brodmann area 4 of human brain. ... Precentral sulcus of the human brain. ... Superior frontal gyrus of the human brain. ... Categories: Stub | Cerebrum ... // Human Brodmann area 8, or BA8, is part of the frontal cortex in the human brain. ... Middle frontal gyrus of the human brain. ... // Where is it? Brodmann area 46, or BA46, is part of the frontal cortex in the human brain. ... Inferior frontal gyrus of the human brain. ... Brocas area is the section of the human brain (in the opercular and triangular sections of the inferior frontal gyrus of the frontal lobe of the cortex) that is involved in language processing, speech production and comprehension. ... Categories: Stub | Cerebrum ... The Pars Opercularis is part of the inferior frontal gyrus and is part of the mirror neurons. ... Categories: Stub | Cerebrum ... The Pars triangularis is a portion of the inferior frontal gyrus. ... // Location and Function The prefrontal cortex is the anterior part of the frontal lobes of the brain, lying in front of the motor and associative areas. ... The orbitofrontal cortex is a region of association cortex the human brain involved in cognitive processes such as decision making. ... Categories: Stub | Cerebrum ... Categories: Stub | Cerebrum ... Categories: Stub | Cerebrum ... The term Brodmann area 12 refers to a subdivision of the cerebral cortex of the guenon defined on the basis of cytoarchitecture. ... Where is it? Brodmann area 47, or BA47, is part of the frontal cortex in the human brain. ...


parietal lobe: postcentral sulcus, postcentral gyrus (1, 2, 3, 43), superior parietal lobule (5), inferior parietal lobule (39-angular gyrus, 40), precuneus (7) The parietal lobe is a lobe in the brain. ... Postcentral sulcus of the human brain. ... The lateral postcentral gyrus is a prominent structure in the parietal lobe of the human brain and an important landmark. ... This page may meet Wikipedias criteria for speedy deletion. ... The superior parietal lobule is bounded in front by the upper part of the postcentral sulcus, but is usually connected with the posterior central gyrus above the end of the sulcus; behind it is the lateral part of the parietoöccipital fissure, around the end of which it is joined... Brodmann area 5 is part of the parietal cortex in the human brain. ... The inferior parietal lobule (subparietal district or lobule) lies below the horizontal portion of the intraparietal sulcus, and behind the lower part of the postcentral sulcus. ... Categories: Stub | Cerebrum ... The angular gyrus is a region of the brain that lies near the superior edge of the temporal lobe, and immediately posterior to the supramarginal gyrus; it is involved in the recognition of visual symbols. ... Brodmann area 40, or BA40, is part of the parietal cortex in the human brain. ... The precuneus is a structure in the brain positioned above the cuneus and located in the parietal lobe. ... Categories: Stub | Cerebrum ...


occipital lobe: primary visual cortex (17), cuneus, lingual gyrus, 18, 19 (18 and 19 span whole lobe) The occipital lobe is the visual processing center of the mammalian brain. ... Visual cortex is the term applied to both the primary visual cortex (also known as striate cortex or V1) and upstream visual cortical areas also known as extrastriate cortical areas (V2, V3, V4, V5). ... Cuneus (Latin for wedge; plural, cunei), the architectural term applied to the wedge-shaped divisions of the Roman theatre separated by the scalae or stairways; see Vitruvius v. ... The lingual gyrus of the occipital lobe lies between the calcarine fissure and the posterior part of the collateral fissure; behind, it reaches the occipital pole; in front, it is continued on to the tentorial surface of the temporal lobe, and joins the hippocampal gyrus. ... Categories: Stub | Cerebrum ... Brodmann area 19 is shown in yellow in this image which also shows ares 17 (red) and 18 (orange) Brodmann area 19, or BA19, is part of the occipital lobe cortex in the human brain. ...


temporal lobe: transverse temporal gyrus (41-42-primary auditory cortex), superior temporal gyrus (38, 22-Wernicke's area), middle temporal gyrus (21), inferior temporal gyrus (20), fusiform gyrus (36, 37) The temporal lobes are part of the cerebrum. ... The transverse temporal gyri (also called Heschls gyri) are found in the area of primary auditory cortex in the superior temporal gyrus of the human brain. ... Brodmann areas 41 & 42 of the human brain. ... Superior temporal gyrus of the human brain. ... Categories: Stub | Cerebrum ... On the left side of the brain is an area called Brodmann’s area 22, that help generate and help the understanding of individual words, and on the right side of the brain it helps tell the difference between melody, pitch, and sound intensity. ... Wernickes area is a part of the human brain that forms part of the cortex, on the left posterior section of the superior temporal gyrus, posterior to the primary auditory cortex, on the temporo-parietal junction (part of the brain where the temporal lobe and parietal lobe meet). ... The location in the brain of the middle temporal gyrus Middle temporal gyrus is a gyrus in the brain on the Temporal lobe. ... Categories: Stub | Cerebrum ... Function of Inferior Temporal Gyrus The Inferior Temporal Gyrus, also known as Brocas area, carries out many tasks, and is mainly responsible for its task in phoenetical analysis for reading. ... Categories: Stub | Cerebrum ... Please observe: the above picture was copied from this fantastic brain atlas The Fusiform gyrus is part of the temporal lobe. ... This area is known as ectorhinal area 36, and it refers to a subdivision of the cytoarchitecturally defined temporal region of cerebral cortex. ... Categories: Stub | Cerebrum ...


limbic lobe/fornicate gyrus: cingulate cortex/cingulate gyrus, anterior cingulate (24, 32, 33), posterior cingulate (23, 31),
isthmus (26, 29, 30), parahippocampal gyrus (piriform cortex, 25, 27, 35), entorhinal cortex (28, 34) The limbic system is a group of brain structures that are involved in various emotions such as aggression, fear, pleasure and also in the formation of memory. ... The Fornicate Gyrus is connected to the amydala, the mid region of the parietal region of the skull. ... The cingulate cortex is part of the brain and situated roughly in the middle of the cortex. ... Cingulate gyrus is a gyrus in the medial part of the brain. ... Grays FIG. 727– Medial surface of left cerebral hemisphere. ... 24 - ventral anterior cingulate (area cingularis anterior ventralis). ... The introduction to this article provides insufficient context for those unfamiliar with the subject matter. ... This area is known as pregenual area 33, and it refers to a subdivision of the cytoarchitecturally defined cingulate region of cerebral cortex. ... The Cingulum is a collection of nerve fibres following a long, arcuate course superior to and around to posterior to the Corpus callosum. ... Brodmann area 23 (BA23) is a region in the brain corresponding to some portion of the posterior cingulate cortex. ... This area is known as dorsal posterior cingulate area 31, and it refers to a subdivision of the cytoarchitecturally defined cingulate region of cerebral cortex. ... In anatomy, isthmus refers to a constriction between organs. ... This article may be too technical for most readers to understand. ... This area is known as granular retrolimbic area 29, and it refers to a cytoarchitecturally defined portion of the retrosplenial region of the cerebral cortex. ... This area is known as agranular retrolimbic area 30, and it refers to a subdivision of the cytoarchitecturally defined retrosplenial region of the cerebral cortex. ... The parahippocampal gyrus is a grey matter cortical region of the brain that surrounds the hippocampus. ... In anatomy of animals, the piriform cortex, or pyriform cortex is a region in the brain. ... // Human Brodmann area 25 (BA25) is an area in the cerebral cortex of the brain and delineated based on its cytoarchitectonic characteristics. ... The term area 27 of Brodmann-1909 refers to a cytoarchitecturally defined cortical area that is a rostral part of the PARAHIPPOCAMPAL GYRUS of the guenon (Brodmann-1909). ... // Human This area is known as perirhinal area 35, and it refers to a subdivision of the cytoarchitecturally defined hippocampal region of the cerebral cortex. ... The entorhinal cortex (EC) is an important memory center in the brain. ... // Guenon The term Brodmann area 28 refers to a subdivision of the cerebral cortex of the guenon defined on the basis of cytoarchitecture. ... You have new messages. ...


subcortical/insular cortex: rhinencephalon, olfactory bulb, corpus callosum, lateral ventricles, septum pellucidum, ependyma, internal capsule, corona radiata, external capsule The insular cortex (also often referred to as just the insula) is a structure of the human brain. ... In anatomy of animals, the rhinencephalon is a part of the brain involved with olfaction. ... Vesalius Fabrica, 1543. ... Grays FIG. 733– Corpus callosum from above. ... The ventricular system is a fluid conducting system within the brain. ... The septum pellucidum, also called the septum lucidum, is a thin, triangular, vertical membrane that separates the lateral ventricles of the brain. ... Ependyma is the thin epithelial membrane lining the ventricular system of the brain and the spinal cord canal Categories: Anatomy stubs | Physiology ... The internal capsule is an area of white matter in the brain that separates the caudate nucleus and the thalamus from the lenticular nucleus. ... The corona radiata surround an ovum or unfertilized egg cell, and consist of two or three strata (layers) of follicular cells. ... The external capsule is a series of white matter fiber tracts in the brain. ...


hippocampus: dentate gyrus, cornu ammonis, subiculum, alveus The location of the hippocampus in the human brain. ... The dentate gyrus is part of the hippocampal formation. ... Daigram of hippocampal regions. ... The subiculum (Latin: support) forms the most inferior portion of the hippocampus. ... The alveus of the hippocampus borders the wall of the lateral ventricle and is composed of white, myelinated fibers. ...


basal ganglia: striatum, caudate nucleus, lentiform nucleus, putamen, globus pallidus, claustrum, extreme capsule, amygdala, nucleus accumbens The basal ganglia are a group of nuclei in the brain associated with motor and learning functions. ... The striatum is a subcortical part of the brain consisting of the caudate nucleus and the putamen. ... Grays Fig. ... The lentiform nucleus or lenticular nucleus describes the putamen and the globus pallidus within the basal ganglia. ... The putamen is a structure in the middle of the brain, forming the striatum together with the caudate nucleus. ... The globus pallidus (Latin for pale body) is a sub-cortical structure in the brain. ... The claustrum is a thin layer of grey matter lying between the extreme capsule and external capsule in the brain. ... The extremem capsule is a series of white matter fiber tracts in the brain. ... Location of the amygdala in the human brain The amygdala (Latin, corpus amygdaloideum) is an almond-shaped set of neurons located deep in the brains medial temporal lobe. ... The nucleus accumbens (also known as the accumbens nucleus or nucleus accumbens septi) is a collection of neurons located where the head of the caudate and the anterior portion of the putamen meet just lateral to the septum pellucidum. ...


Some categorizations are approximations, and some Brodmann areas span gyri.


  Results from FactBites:
 
Medical Neurosciences (974 words)
In contrast, the cells of origin of the lateral corticospinal tract lie in the contralateral cerebral cortex.
This is because the lateral corticospinal tract influences the musculature on the same (ipsilateral) side of the body.
Cerebrovascular accidents (“strokes”) commonly damage the corticospinal tract in the motor cortex or the posterior limb of the internal capsule (a compact bundle of axons through which almost all neural traffic to and from the cortex passes).
  More results at FactBites »

 
 

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