query: where are descending tracts found in the spinal cord

pos: Lateral corticospinal tract begins in the cerebral cortex, decussates in the pyramids of the lower medulla (also known as the medulla oblongata or the cervicomedullary junction, which is the most posterior division of the brain) and proceeds down the contralateral side of the spinal cord. It is the largest part of the corticospinal tract. It extends throughout the entire length of the medulla spinalis, and on transverse section appears as an oval area in front of the posterior column and medial to the posterior spinocerebellar tract. Axons in the lateral corticospinal tract leave out of the tract and into the anterior horns of

pos: Anterior corticospinal tract Anterior corticospinal tract The anterior corticospinal tract (also called the ventral corticospinal tract, "Bundle of Turck", medial corticospinal tract, direct pyramidal tract, or anterior cerebrospinal fasciculus) is a small bundle of descending fibers that connect the cerebral cortex to the spinal cord. Descending tracts are pathways by which motor signals are sent from upper motor neurons in the brain to lower motor neurons which then directly innervate muscle to produce movement. The anterior corticospinal tract is usually small, varying inversely in size with the lateral corticospinal tract, which is the main part of the corticospinal tract. It lies close to

pos: Spinal cord side as the ventral corticospinal tract. These axons also synapse with lower motor neurons in the ventral horns. Most of them will cross to the contralateral side of the cord (via the anterior white commissure) right before synapsing. The midbrain nuclei include four motor tracts that send upper motor neuronal axons down the spinal cord to lower motor neurons. These are the rubrospinal tract, the vestibulospinal tract, the tectospinal tract and the reticulospinal tract. The rubrospinal tract descends with the lateral corticospinal tract, and the remaining three descend with the anterior corticospinal tract. The function of lower motor neurons can

pos: Lateral corticospinal tract Lateral corticospinal tract The lateral corticospinal tract (also called the crossed pyramidal tract or lateral cerebrospinal fasciculus) is the largest part of the corticospinal tract. It extends throughout the entire length of the spinal cord, and on transverse section appears as an oval area in front of the posterior column and medial to the posterior spinocerebellar tract. Descending motor pathways carry motor signals from the brain down the spinal cord and to the target muscle or organ. They typically consist of an upper motor neuron and a lower motor neuron. The lateral corticospinal tract is a descending motor pathway that

pos: Medullary pyramids (brainstem) axons decussate (or cross over) the midline and continue down the spinal cord on the contralateral side. The fibers that decussated will go down the lateral corticospinal tract while the fibers that did not decussate will travel down the anterior corticospinal tract. Nearly 90 percent of the fibers decussate and travel down the lateral corticospinal tract while the other 10 percent travels down the anterior corticospinal tract. The two pyramids contain the motor fibers that pass from the brain to the medulla oblongata and spinal cord. These are the corticobulbar and corticospinal fibers that make up the pyramidal tracts. About

pos: Spinal cord be divided into two different groups: the lateral corticospinal tract and the anterior cortical spinal tract. The lateral tract contains upper motor neuronal axons which synapse on dorsal lateral (DL) lower motor neurons. The DL neurons are involved in distal limb control. Therefore, these DL neurons are found specifically only in the cervical and lumbosacral enlargements within the spinal cord. There is no decussation in the lateral corticospinal tract after the decussation at the medullary pyramids. The anterior corticospinal tract descends ipsilaterally in the anterior column, where the axons emerge and either synapse on lower ventromedial (VM) motor neurons in

pos: Pyramidal tracts a lower motor neuron. This generally occurs in the anterior grey column. Nerve axons of the lateral corticospinal tract that did not cross over in the medulla oblongata do so at the level of the spinal cord they terminate in. These tracts contain more than 1 million axons and the majority of the axons are myelinated. The corticospinal tracts myelinate largely during the first and second years after birth. The majority of nerve axons are small (<4μm) in diameter. About 3% of nerve axons have a much larger diameter (16μm) and arise from Betz cells, mostly in the leg area

neg: Spinal cord the spinal cord via descending spinal cord tracts. Descending tracts involve two neurons: the upper motor neuron (UMN) and lower motor neuron (LMN). A nerve signal travels down the upper motor neuron until it synapses with the lower motor neuron in the spinal cord. Then, the lower motor neuron conducts the nerve signal to the spinal root where efferent nerve fibers carry the motor signal toward the target muscle. The descending tracts are composed of white matter. There are several descending tracts serving different functions. The corticospinal tracts (lateral and anterior) are responsible for coordinated limb movements. A congenital disorder

neg: Motor neuron these descending tracts carry impulses from different regions. These tracts also serve as the place of origin for lower motor neurons. There are seven major descending motor tracts to be found in the spinal cord: Lower motor neurons are those that originate in the spinal cord and directly or indirectly innervate effector targets. The target of these neurons varies, but in the somatic nervous system the target will be some sort of muscle fiber. There are three primary categories lower motor neurons, which can be further divided in sub-categories. According to their targets, motor neurons are classified into three broad

neg: Medial vestibulospinal tract Medial vestibulospinal tract The medial vestibulospinal tract is one of the descending spinal tracts of the ventromedial funiculus of the spinal cord. It is found only in the cervical spine and above. The medial part of the vestibulospinal tract is the smaller part, and is primarily made of fibers from the medial vestibular nucleus. It projects bilaterally down the spinal cord and triggers the ventral horn of the cervical spinal circuits, particularly controlling lower motor neurons associated with the spinal accessory nerve (CN XI). Additionally, the pathway projects superiorly to the paramedian pontine reticular formation, indirectly innervating the nuclei of

neg: Ventral propriospinal tract tract is one of three propriospinal tracts in which most pathways intrinsic to the spinal cord are located. The others are the dorsal propriospinal tract and the lateral propriospinal tract., Ventral propriospinal tract Ventral propriospinal tract is a collection of nerve fibers, ascending, descending, crossed and uncrossed, that interconnect various levels of the spinal cord. It is a component of the white anterior columns. The fibers are largely myelinated and run close to the spinal central gray for the length of the cord. Shorter fibers are closer to, longer fibers further from the gray. Other prominent components of the anterior

neg: Medial vestibulospinal tract CN VI and III. Through this superior projection, the medial vestibulospinal tract is involved in "yoking" the eyes together in response to rapid movement of the head. Thus, cumulatively it controls head and whole body orientation. Medial vestibulospinal tract The medial vestibulospinal tract is one of the descending spinal tracts of the ventromedial funiculus of the spinal cord. It is found only in the cervical spine and above. The medial part of the vestibulospinal tract is the smaller part, and is primarily made of fibers from the medial vestibular nucleus. It projects bilaterally down the spinal cord and triggers the

neg: Spinal cord spinal nerves originating in the upper lumbar region. Within the CNS, nerve cell bodies are generally organized into functional clusters, called nuclei. Axons within the CNS are grouped into tracts. There are 31 spinal cord nerve segments in a human spinal cord: In the fetus, vertebral segments correspond with spinal cord segments. However, because the vertebral column grows longer than the spinal cord, spinal cord segments do not correspond to vertebral segments in the adult, particularly in the lower spinal cord. For example, lumbar and sacral spinal cord segments are found between vertebral levels T9 and L2, and the spinal

neg: Proper fasciculi occupy the ventral part of the funiculus close to the grey column. They are intersegmental and run for varying distances sending off collaterals and terminals to the grey matter. Proper fasciculi The proper fasciculi, or spinospinal fasciculi, or propriospinal tracts, are groups of short fibres, ascending and descending, and crossed and uncrossed, within the spinal cord. These fibres are grouped into anterior, posterior, and lateral regions and make up a spinal pathway. Descending dorsal root collaterals are often included in the pathway. The anterior proper fasciculus consists of longitudinal intersegmental fibres which arise from cells in the grey matter, more

neg: Proper fasciculi Proper fasciculi The proper fasciculi, or spinospinal fasciculi, or propriospinal tracts, are groups of short fibres, ascending and descending, and crossed and uncrossed, within the spinal cord. These fibres are grouped into anterior, posterior, and lateral regions and make up a spinal pathway. Descending dorsal root collaterals are often included in the pathway. The anterior proper fasciculus consists of longitudinal intersegmental fibres which arise from cells in the grey matter, more especially from those of the medial group of the anterior column, and, after a longer or shorter course, re-enter the gray substance; and fibres which cross in the anterior

neg: Reticular formation supplying the trunk and proximal limb flexors and extensors. The reticulospinal tracts are involved mainly in locomotion and postural control, although they do have other functions as well. The descending reticulospinal tracts are one of four major cortical pathways to the spinal cord for musculoskeletal activity. The reticulospinal tracts works with the other three pathways to give a coordinated control of movement, including delicate manipulations. The four pathways can be grouped into two main system pathways – a medial system and a lateral system. The medial system includes the reticulospinal pathway and the vestibulospinal pathway, and this system provides control

neg: Neural substrate of locomotor central pattern generators in mammals where locomotor neurons are located. They are in cells that express the HB9 transcription factor, which were shown to be rhythmically active during fictive locomotion in the mouse spinal cord. The supralumbar segments of the spinal cord are the most effective site for 5-HT to induce locomotion in the neonatal rat. 5-HT elicits locomotion in the spinal cord when applied to the thoracic cord, as well as directly to the upper lumbar segments of the spinal cord. More specifically, the serotonergic descending pathway originates in the parapyramidal region (PPR) of the medulla. Brainstem evoked locomotion can be blocked by 5-HT

neg: Lateral rectus muscle crosses to the contralateral side of the midbrain. The tectospinal tract descends through the brainstem to the upper spinal cord, but goes no further than the neck. This tract is involved with both upper and lower motor neurons, as well as in the reflex of turning the head in response to visual and auditory stimulus. Part of the descending tracts carry motor signals down the brainstem and spinal cord. A sixth nerve palsy, also known as abducens nerve palsy, is a neurological defect that results from a damaged or impaired abducens nerve. This damage can stem from stroke, trauma, tumor,

neg: Neural pathway route from the entorhinal cortex to all fields of the hippocampal formation, including the dentate gyrus, all CA fields (including CA1), and the subiculum. Descending motor pathways of the pyramidal tracts travel from the cerebral cortex to the brainstem or lower spinal cord. Ascending sensory tracts in the dorsal column–medial lemniscus pathway (DCML) carry information from the periphery to the cortex of the brain. The first named pathways are evident to the naked eye even in a poorly preserved brain, and were named by the great anatomists of the Renaissance using cadaver material. Examples of these include the great "commissures"

neg: Allodynia located on both sides of the spinal cord. The axons then pass through the dorsal horn to make connections with secondary neurons. The secondary neurons cross over to the other (contralateral) side of the spinal cord and reach nuclei of the thalamus. From there, the information is carried through one or more neurons to the somatosensory cortex of the brain. Mechanoreceptors follow the same general pathway. However, they do not cross over at the level of the spinal cord, but at the lower medulla instead. In addition, they are grouped in tracts that are spatially distinct from the nociceptive tracts.

neg: Spinal cord injury impingement on the spinal cord by a tumor or vertebral disk. Anterior cord syndrome, due to damage to the front portion of the spinal cord or reduction in the blood supply from the anterior spinal artery, can be caused by fractures or dislocations of vertebrae or herniated disks. Below the level of injury, motor function, pain sensation, and temperature sensation are lost, while sense of touch and proprioception (sense of position in space) remain intact. These differences are due to the relative locations of the spinal tracts responsible for each type of function. Brown-Séquard syndrome occurs when the spinal cord

neg: LINGO1 come from endogenous or exogenous processes. Spinal cord injury results in the damage of the axonal tracts whose function is to control motor and sensory activity. This protein has been found in this axonal tracts of adolescent rat spinal cords following injury. Furthermore, a five time increase in Lingo-1 mRNA levels was detected 14 days post injury. Lingo-1-Fc, a soluble form of Lingo-1, has also been shown to antagonize Lingo-1 signaling pathways by inhibiting the binding of Lingo-1 to NgR, in consequence, vast improvements in the functional recovery of rats following lateral hemisection of the spinal cord were observed. Essential

neg: Ventral propriospinal tract Ventral propriospinal tract Ventral propriospinal tract is a collection of nerve fibers, ascending, descending, crossed and uncrossed, that interconnect various levels of the spinal cord. It is a component of the white anterior columns. The fibers are largely myelinated and run close to the spinal central gray for the length of the cord. Shorter fibers are closer to, longer fibers further from the gray. Other prominent components of the anterior columns are the medial longitudinal fasciculus of the spinal cord, the anterior spinothalamic tract of the spinal cord and the lateral vestibulospinal tract of the spinal cord. The ventral propriospinal

neg: PLXNA4A nucleus. Fibers expressed Plexin A4 in the lateral septum, nucleus accumbens, several thalamic nuclei, substantia nigra pars reticulata, zona incerta, pontine reticular formation, as well as in several cranial nerve nuclei. Plexin A4 has been found in dorsal and, to a greater extent, ventral horns of the spinal cord. Both motor neurons and interneurons in the ventral horn express Plexin A4. Motor axons exiting via the ventral roots and the ascending and descending white matter tracts express Plexin A4. In dorsal root ganglia, Plexin A4 is expressed in the neuronal cell bodies as well as the central and peripheral processes

neg: Central nervous system spinal cord has certain processing ability such as that of spinal locomotion and can process reflexes, the brain is the major processing unit of the nervous system. The brainstem consists of the medulla, the pons and the midbrain. The medulla can be referred to as an extension of the spinal cord, and its organization and functional properties are similar to those of the spinal cord. The tracts passing from the spinal cord to the brain pass through here. Regulatory functions of the medulla nuclei include control of the blood pressure and breathing. Other nuclei are involved in balance, taste, hearing

neg: Pyramidal tracts Pyramidal tracts The pyramidal tracts include both the corticobulbar tract and the corticospinal tract. These are aggregations of efferent nerve fibers from the upper motor neurons that travel from the cerebral cortex and terminate either in the brainstem ("corticobulbar") or spinal cord ("corticospinal") and are involved in the control of motor functions of the body. The corticobulbar tract conducts impulses from the brain to the cranial nerves. These nerves control the muscles of the face and neck and are involved in facial expression, mastication, swallowing, and other functions. The corticospinal tract conducts impulses from the brain to the spinal cord.

neg: Spinal cord injury is loss of sensation of pain, temperature, light touch, and pressure below the level of injury. The spinal tracts that serve the arms are more affected due to their central location in the spinal cord, while the corticospinal fibers destined for the legs are spared due to their more external location. The most common of the incomplete SCI syndromes, central cord syndrome usually results from neck hyperextension in older people with spinal stenosis. In younger people, it most commonly results from neck flexion. The most common causes are falls and vehicle accidents; however other possible causes include spinal stenosis and

neg: Human brain vibration and temperature. From the joints, the brain receives information about joint position. The sensory cortex is found just near the motor cortex, and, like the motor cortex, has areas related to sensation from different body parts. Sensation collected by a sensory receptor on the skin is changed to a nerve signal, that is passed up a series of neurons through tracts in the spinal cord. The dorsal column–medial lemniscus pathway contains information about fine touch, vibration and position of joints. Neurons travel up the back part of the spinal cord to the back part of the medulla, where they

neg: Tethered spinal cord syndrome Tethered spinal cord syndrome Tethered cord syndrome (TCS) or occult spinal dysraphism sequence refers to a group of neurological disorders that relate to malformations of the spinal cord. Various forms include tight filum terminale, lipomeningomyelocele, split cord malformations (diastematomyelia), dermal sinus tracts, and dermoids. All forms involve the pulling of the spinal cord at the base of the spinal canal, literally a cord. The spinal cord normally hangs loose in the canal, free to move up and down with growth, and with bending and stretching. A tethered cord, however, is held taut at the end or at some point in

neg: Lateral vestibulospinal tract or the flocculi and nodulus. The cerebellum aids in coordinating postural adjustments. Lateral vestibulospinal tract The lateral vestibulospinal tract is one of the descending spinal tracts of the ventromedial funiculus. The lateral part of the vestibulospinal tract is the major portion and is composed of fibers originating in the lateral, superior, and inferior vestibular nuclei (primarily the lateral). It projects ipsilaterally down to the lumbar region of the spinal cord. There it helps to maintain an upright and balanced posture by stimulating extensor motor neurons in the legs. It also innervates muscles of the trunk, thus additionally aiding in body

neg: Cerebral peduncle Cerebral peduncle The cerebral peduncles are structures at the front of the midbrain which arise from the front of the pons and contain the large ascending (sensory) and descending (motor) nerve tracts that run to and from the cerebrum from the pons. Mainly, the three common areas that give rise to the cerebral peduncles are the cerebral cortex, the spinal cord and the cerebellum. The cerebral peduncle, by most classifications, is everything in the midbrain except the tectum. The region includes the tegmentum, crus cerebri and pretectum. By this definition, the cerebral peduncles are also known as the basis pedunculi,

neg: Lateral vestibulospinal tract Lateral vestibulospinal tract The lateral vestibulospinal tract is one of the descending spinal tracts of the ventromedial funiculus. The lateral part of the vestibulospinal tract is the major portion and is composed of fibers originating in the lateral, superior, and inferior vestibular nuclei (primarily the lateral). It projects ipsilaterally down to the lumbar region of the spinal cord. There it helps to maintain an upright and balanced posture by stimulating extensor motor neurons in the legs. It also innervates muscles of the trunk, thus additionally aiding in body posture. The lateral vestibular nuclei receive input from cerebellum, particularly the vestibulocerebellum,

neg: Cerebral peduncle between the two cerebral peduncles in the interpeduncular fossa. Cranial nerve 4 (trochlear nerve) wraps around the lowest part of the cerebral peduncle. Cerebral peduncle The cerebral peduncles are structures at the front of the midbrain which arise from the front of the pons and contain the large ascending (sensory) and descending (motor) nerve tracts that run to and from the cerebrum from the pons. Mainly, the three common areas that give rise to the cerebral peduncles are the cerebral cortex, the spinal cord and the cerebellum. The cerebral peduncle, by most classifications, is everything in the midbrain except the

neg: Neuromere called nuclei. Axons within the CNS are grouped into tracts. There are 33 spinal cord nerve segments in a human spinal cord: 8 cervical segments forming 8 pairs of cervical nerves (C1 spinal nerves exit spinal column between occiput and C1 vertebra; C2 nerves exit between posterior arch of C1 vertebra and lamina of C2 vertebra; C3-C8 spinal nerves through IVF above corresponding cervica vertebra, with the exception of C8 pair which exit via IVF between C7 and T1 vertebra) 12 thoracic segments forming 12 pairs of thoracic nerves (exit spinal column through IVF below corresponding vertebra T1-T12) 5 lumbar

neg: Reticular formation Reticular formation The reticular formation is a set of interconnected nuclei that are located throughout the brainstem. The reticular formation is not anatomically well defined because it includes neurons located in diverse parts of the brain. The neurons of the reticular formation make up a complex set of networks in the core of the brainstem that stretch from the upper part of the midbrain to the lower part of the medulla oblongata. The reticular formation includes ascending pathways to the cortex in the ascending reticular activating system (ARAS) and descending pathways to the spinal cord via the reticulospinal tracts of

neg: Sam Schmidt Paralysis Foundation and injury to a particular part of the cord will impact neighboring parts of the body. Paralysis occurs when communication between the brain and spinal cord fails. This can result from injury to neurons in the brain (a stroke), or in the spinal cord. Trauma to the spinal cord affects only the areas below the level of injury. On the other hand, poliomyelitis (a viral infection) or Lou Gehrig's disease (ALS, amyotrophic lateral sclerosis) can affect neurons in the entire spinal cord. The spinal cord contains multiple tracts to transmit different information. Specialized neurons carry messages from the skin, muscles,

neg: Anterior spinal artery syndrome Anterior spinal artery syndrome Anterior spinal artery syndrome (also known as "anterior spinal cord syndrome") is syndrome caused by ischemia of the anterior spinal artery, resulting in loss of function of the anterior two-thirds of the spinal cord. The region affected includes the descending corticospinal tract, ascending spinothalamic tract, and autonomic fibers. It is characterized by a corresponding loss of motor function, loss of pain and temperature sensation, and hypotension. Anterior spinal artery syndrome is the most common form of spinal cord infarction. The anterior spinal cord is at increased risk for infarction because it is supplied by the single

neg: Pyramidal tracts of the spinal cord until they synapse with interneurons in the grey column of the spinal cord. There is some variation in terminology. The "pyramidal tracts" definitively encompass the corticospinal tracts, and many authors also include the corticobulbar tracts. Nerve fibres in the corticospinal tract originate from pyramidal cells in layer V of the cerebral cortex. Fibres arise from the primary motor cortex (about 30%), supplementary motor area and the premotor cortex (together also about 30%), and the somatosensory cortex, parietal lobe, and cingulate gyrus supplies the rest. The cells have their bodies in the cerebral cortex, and the axons

neg: Dissociated sensory loss Dissociated sensory loss Dissociated sensory loss is a pattern of neurological damage caused by a lesion to a single tract in the spinal cord which involves "selective" loss of fine touch and proprioception "without" loss of pain and temperature, or vice versa. Understanding the mechanisms behind these selective lesions requires a brief discussion of the anatomy involved. Loss of pain and temperature are due to damage to the lateral spinothalamic tracts, which cross the central part of the cord close to the level where they enter it and travel up the spinal column on the opposite side to the one

neg: Friedreich's ataxia position-effect variegation. The primary site of pathology is in the spinal cord and peripheral nerves. Sclerosis and degeneration of dorsal root ganglion, spinocerebellar tracts, lateral corticospinal tracts, and posterior columns. The motor neurons of the spinal cord are spared. In peripheral nerves there is a loss of large myelinated fibres. Progressive destruction of dorsal root ganglia accounts for thinning of dorsal roots, degeneration of dorsal columns, transsynaptic atrophy of nerve cells in Clarke's column and dorsal spinocerebellar fibers, atrophy of gracile and cuneate nuclei and neuropathy of sensory nerves. The lesion of the dentate nucleus consists of progressive and selective

neg: Anterior spinal artery Anterior spinal artery In human anatomy, the anterior spinal artery is the artery that supplies the anterior portion of the spinal cord. It arises from branches of the vertebral arteries and courses along the anterior aspect of the spinal cord. It is reinforced by several contributory arteries, especially the artery of Adamkiewicz. The anterior spinal artery arises bilaterally as two small branches near the termination of the vertebral arteries. One of these vessels is usually larger than the other, but occasionally they are about equal in size. Descending in front of the medulla oblongata, they unite at the level of

neg: Neuromere spinal segments form a bundle called the cauda equina. There are two regions where the spinal cord enlarges: Cervical enlargement - corresponds roughly to the brachial plexus nerves, which innervate the upper limb. It includes spinal cord segments from about C4 to T1. The vertebral levels of the enlargement are roughly the same (C4 to T1). Lumbosacral enlargement - corresponds to the lumbosacral plexus nerves, which innervate the lower limb. It comprises the spinal cord segments from L2 to S3 and is found about the vertebral levels of T9 to T12. The spinal cord is made from part of the

neg: Gate control theory third ventricle and the cerebral aqueduct of the ventricular system. Stimulation of this area produces analgesia (but not total numbing) by activating descending pathways that directly and indirectly inhibit nociceptors in the laminae of the spinal cord. Descending pathways also activate opioid receptor-containing parts of the spinal cord. Afferent pathways interfere with each other constructively, so that the brain can control the degree of pain that is perceived, based on which pain stimuli are to be ignored to pursue potential gains. The brain determines which stimuli are profitable to ignore over time. Thus, the brain controls the perception of pain

neg: Extrapyramidal system Extrapyramidal system In anatomy, the extrapyramidal system is a part of the motor system network causing involuntary actions. The system is called "extrapyramidal" to distinguish it from the tracts of the motor cortex that reach their targets by traveling through the pyramids of the medulla. The pyramidal pathways (corticospinal and some corticobulbar tracts) may directly innervate motor neurons of the spinal cord or brainstem (anterior (ventral) horn cells or certain cranial nerve nuclei), whereas the extrapyramidal system centers on the modulation and regulation (indirect control) of anterior (ventral) horn cells. Extrapyramidal tracts are chiefly found in the reticular formation of

neg: Upper motor neuron tracts. The upper motor neuron descends in the spinal cord to the level of the appropriate spinal nerve root. At this point, the upper motor neuron synapses with the lower motor neuron, each of whose axons innervate a fiber of skeletal muscle. These neurons connect the brain to the appropriate level in the spinal cord, from which point nerve signals continue to the muscles by means of the lower motor neurons. The neurotransmitter glutamate transmits the nerve impulses from upper to lower motor neurons, where it is detected by glutamatergic receptors. Upper motor neurons travel in several neural pathways through

neg: Trigeminal nerve areas) preserve pain-temperature sensation in the nose (V), upper lip (V) and mouth (V) and remove pain-temperature sensation from the forehead (V), cheeks (V) and chin (V). Although analgesia in this distribution is "nonphysiologic" in the traditional sense (because it crosses several dermatomes), this analgesia is found in humans after surgical sectioning of the spinal tract of the trigeminal nucleus. The spinal trigeminal nucleus sends pain-temperature information to the thalamus and sends information to the mesencephalon and the reticular formation of the brainstem. The latter pathways are analogous to the spinomesencephalic and spinoreticular tracts of the spinal cord, which send

neg: Spinal interneuron into the contralateral spinal cord. At that location, the interneuron excites the alpha motor neurons that innervate the extensor muscles of the opposite leg. This allows for balance and body posture to be maintained. Spinal interneuron A spinal interneuron, found in the spinal cord, relays signals between (afferent) sensory neurons, and (efferent) motor neurons. Different classes of spinal interneurons are involved in the process of sensory-motor integration. Most interneurons are found in the grey column, a region of grey matter in the spinal cord. The grey column of the spinal cord appears to have groups of small neurons, often referred

neg: Spinal interneuron a population of glutamatergic V2a neurons and inhibitory V2b neurons, project ispilaterally and caudally across multiple spinal cord regions. The class V1 neurons give rise to two local circuit inhibitory neurons known as Renshaw cells and Ia inhibitory interneurons. The integration of the sensory feedback signals and central motor commands at several levels of the central nervous system plays a critical role in controlling movement. Research on cat's spinal cord has shown that at the spinal cord level sensory afferents and descending motor pathways converge onto common spinal interneurons. Human studies since the 1970s have documented how this integration of

neg: Spinal locomotion of human fetuses at 13–14 gestational weeks "creeping and climbing" and producing alternating steps. Onset of stepping in the fetus precedes development and myelination of most descending brain pathways strongly suggesting human spinal cord locomotor CPG and sensory feedback coordination and plasticity. Collectively, studies across the first postnatal year indicates that a locomotor continuum extends from neonatal stepping to the onset of independent walking further suggesting human locomotion is controlled by CPG and sensory input interaction. The injured spinal cord is an “altered” spinal cord. After a SCI, supraspinal and spinal sources of control of movement differ substantially from that

neg: Vestibulospinal tract upper motor neuron tract consisting of two sub-pathways: The lateral vestibulospinal tract is a group of descending extrapyramidal motor neurons, or efferent nerve fibers. This tract is found in the lateral funiculus, a bundle of nerve roots in the spinal cord. The lateral vestibulospinal tract originates in the lateral vestibular nucleus or Deiters’ nucleus in the pons. The Deiters' nucleus extends from pontomedullary junction to the level of abducens nerve nucleus in the pons. Lateral vestibulospinal fibers descend uncrossed, or ipsilateral, in the anterior portion of the lateral funiculus of the spinal cord. Fibers run down the total length of

neg: Vestibulospinal tract the spinal cord and terminate at the interneurons of laminae VII and VIII. Additionally, some neurons terminate directly on the dendrites of alpha motor neurons in the same laminae. The medial vestibulospinal tract is a group of descending extrapyramidal motor neurons, or efferent fibers found in the anterior funiculus, a bundle of nerve roots in the spinal cord. The medial vestibulospinal tract originates in the medial vestibular nucleus or Schwalbe's nucleus. The Schwalbe's nucleus extends from the rostral end of the inferior olivary nucleus of the medulla oblongata to the caudal portion of the pons. Medial vestibulospinal fibers join with

neg: Solitary tract Solitary tract The solitary tract () is a compact fiber bundle that extends longitudinally through the posterolateral region of the medulla. The solitary tract is surrounded by the nucleus of the solitary tract, and descends to the upper cervical segments of the spinal cord. It was first named by Theodor Meynert in 1872. The solitary tract is made up of primary sensory fibers and descending fibers of the vagus, glossopharyngeal, and facial nerves. The solitary tract conveys afferent information from stretch receptors and chemoreceptors in the walls of the cardiovascular, respiratory, and intestinal tracts. Afferent fibers from cranial nerves 7,

neg: Spinal interneuron Spinal interneuron A spinal interneuron, found in the spinal cord, relays signals between (afferent) sensory neurons, and (efferent) motor neurons. Different classes of spinal interneurons are involved in the process of sensory-motor integration. Most interneurons are found in the grey column, a region of grey matter in the spinal cord. The grey column of the spinal cord appears to have groups of small neurons, often referred to as spinal interneurons, that are neither primary sensory cells nor motor neurons. The versatile properties of these spinal interneurons cover a wide range of activities. Their functions include the processing of sensory input,

neg: Pain in fish fibres. The central nervous system (CNS) of fish contains a spinal cord, medulla oblongata, and the brain, divided into telencephalon, diencephalon, mesencephalon and cerebellum. In fish, similar to other vertebrates, nociception travels from the peripheral nerves along the spinal nerves and is relayed through the spinal cord to the thalamus. The thalamus is connected to the telencephalon by multiple connections through the grey matter pallium, which has been demonstrated to receive nerve relays for noxious and mechanical stimuli. The major tracts that convey pain information from the periphery to the brain are the spinothalamic tract (body) and the trigeminal tract

neg: Posterolateral tract During a complete occlusion of the ventral artery of the spinal cord, it is the only tract spared along with the dorsal columns. The posterolateral spinal tracts are involved with neurological deficits seen in pernicious anemia. The "tract of Lissauer" was named after German neurologist Heinrich Lissauer (1861-1891). Posterolateral tract The posterolateral tract (fasciculus of Lissauer, Lissauer's tract, tract of Lissauer, dorsolateral fasciculus, dorsolateral tract, zone of Lissauer) is a small strand situated in relation to the tip of the posterior column close to the entrance of the posterior nerve roots. It is present throughout the spinal cord, and is

neg: Spinal interneuron least 17 different subclasses of interneurons with ipsilateral axon projections were found. In addition, 18 types of commissural interneurons have been identified on the basis of morphology and location. In particular, the cell bodies of the spinal interneurons are found in the grey matter of the spinal cord, which also contains the motor neurons. In 1952, the grey matter of the cat's spinal cord was investigated, and it was shown to have ten distinct zones referred to as Rexed laminae. Eventually, the lamination pattern was also observed in several species including humans. Rexed laminae VII and VIII are locations where

neg: Evoked potential corticospinal tract, are located in the lateral and ventral funiculi of the spinal cord. Since the ventral and dorsal spinal cord have separate blood supply with very limited collateral flow, an anterior cord syndrome (paralysis or paresis with some preserved sensory function) is a possible surgical sequela, so it is important to have monitoring specific to the motor tracts as well as dorsal column monitoring. Transcranial magnetic stimulation versus electrical stimulation is generally regarded as unsuitable for intraoperative monitoring because it is more sensitive to anesthesia. Electrical stimulation is too painful for clinical use in awake patients. The two modalities

neg: Spinothalamic tract nervous system, the anterolateral system is an ascending pathway that conveys pain, temperature (protopathic sensation), and crude touch from the periphery to the brain. It comprises three main pathways: In contrast to the axons of second-order neurons in dorsal column-medial lemniscus pathway, the axons of second-order neurons in the spinothalamic tracts cross at every segmental level in the spinal cord. This fact aids in determining whether a lesion is in the brain or the spinal cord. With lesions in the brain stem or higher, deficits of pain perception, touch sensation, and proprioception are all contralateral to the lesion. With spinal

neg: Central nervous system (cerebrum as well as midbrain and hindbrain) consists of a cortex, composed of neuron-bodies constituting gray matter, while internally there is more white matter that form tracts and commissures. Apart from cortical gray matter there is also subcortical gray matter making up a large number of different nuclei. From and to the spinal cord are projections of the peripheral nervous system in the form of spinal nerves (sometimes segmental nerves). The nerves connect the spinal cord to skin, joints, muscles etc. and allow for the transmission of efferent motor as well as afferent sensory signals and stimuli. This allows for

neg: Medial longitudinal fasciculus the third ventricle, just above the cerebral aqueduct. The medial longitudinal fasciculus carries information about the direction that the eyes should move. It connects the cranial nerve nuclei III (Oculomotor nerve), IV (Trochlear nerve) and VI (Abducens nerve) together, and integrates movements directed by the gaze centers (frontal eye field) and information about head movement (from cranial nerve VIII, Vestibulocochlear nerve). It is an integral component of saccadic eye movements as well as vestibulo-ocular and optokinetic reflexes. It also carries the descending tectospinal tract and medial vestibulospinal tracts into the cervical spinal cord, and innervates some muscles of the neck

neg: Lateral grey column acetylcholine, while postganglionic sympathetic nerve cells use norepinephrine. Grey matter in the brain and spinal cord is any accumulation of cell bodies and neuropil (neuropil is tissue rich in nerve cell bodies and dendrites). White matter consists of nerve tracts (groups of axons) and commissures (tracts that cross the brain's midline). The nervous system is divided into the central nervous system (brain and spinal cord) and the peripheral nervous system (everything else). The peripheral nervous system is divided into the somatic nervous system (voluntary processes) and the autonomic nervous system (involuntary processes). The autonomic nervous system is divided into the

neg: Spinal cord matter tracts containing sensory and motor axons. Internal to this peripheral region is the grey matter, which contains the nerve cell bodies arranged in the three grey columns that give the region its butterfly-shape. This central region surrounds the central canal, which is an extension of the fourth ventricle and contains cerebrospinal fluid. The spinal cord is elliptical in cross section, being compressed dorsolaterally. Two prominent grooves, or sulci, run along its length. The posterior median sulcus is the groove in the dorsal side, and the anterior median fissure is the groove in the ventral side. The human spinal cord

neg: Intraoperative neurophysiological monitoring example, the hardware can be removed. More recently, transcranial electric motor evoked potentials (TCeMEP) have also been used for spinal cord monitoring. This is the reverse of SSEP; the motor cortex is stimulated transcranially, and recordings made from muscles in the limbs, or from spinal cord caudal to the surgery. This allows direct monitoring of motor tracts in the spinal cord. EEG electroencephalography is used for monitoring of cerebral function in neurovascular cases (cerebral aneurysms, carotid endarterectomy) and for defining tumor margins in epilepsy surgery and some cerebral tumors. EEG measures taken during anesthesia exhibit stereotypic changes as anesthetic depth

neg: Cordotomy where percutaneous cordotomy is unfeasible, especially in children or other patients who are unable to co-operate. In open cordotomy, a thoracic approach is normally used so that the spinal cord tracts controlling the breathing muscles are not put at risk. Cordotomy can be highly effective in relieving pain, but there are significant side effects. These include dysesthesia (abnormal sensation), urinary retention and (for bilateral cervical cordotomy) apnoea during sleep (acquired central hypoventilation syndrome) caused by inadvertent division of the reticulospinal tracts. Cordotomy was first performed in 1912 by the American Neurosurgeons, William Gibson Spiller (1863–1940) and Edward Martin (1859–1938). Due

neg: Central nervous system voluntary and involuntary motions of muscles, as well as the perception of senses. All in all 31 spinal nerves project from the brain stem, some forming plexa as they branch out, such as the brachial plexa, sacral plexa etc. Each spinal nerve will carry both sensory and motor signals, but the nerves synapse at different regions of the spinal cord, either from the periphery to sensory relay neurons that relay the information to the CNS or from the CNS to motor neurons, which relay the information out. The spinal cord relays information up to the brain through spinal tracts through

neg: Interventional pain management root ganglion possibly the more effective target because some sensory fibers enter the spinal cord from the dorsal root ganglion via the "ventral" (motor) root, and these would not be interrupted by dorsal root neurectomy. Because nerves often carry both sensory and motor fibers, motor impairment is a possible side effect of neurectomy. A common result of this procedure is "deafferentation pain" where, 6–9 months after surgery, pain returns at greater intensity. Cordotomy involves cutting into the spinothalamic tracts, which run up the front/side (anterolateral) quadrant of the spinal cord, carrying heat and pain signals to the brain. Pancoast tumor

neg: Spinal locomotion Spinal locomotion The spinal cord executes rhythmical and sequential activation of muscles in locomotion. The central pattern generator (CPG) provides the basic locomotor rhythm and synergies by integrating commands from various sources that serve to initiate or modulate its output to meet the requirements of the environment. CPG within the lumbosacral spinal cord segments represent an important component of the total circuitry that generates and controls posture and locomotion. This spinal circuitry can function independently in the absence of descending input from the brain to generate stable posture and locomotion and even modulate activity to match changing conditions (e.g., stepping

neg: Spino-olivary tract Spino-olivary tract The spino-olivary tract (historically Helweg's tract) is located in the anterior funiculus of the spinal cord and provides transmission of unconscious proprioception and is involved in balance. This tract carries proprioception information from muscles and tendons as well as cutaneous impulses to the olivary bodies. The olivary bodies known also as the olives, are located in the medulla oblongata in the brainstem. Other tracts that carry proprioception are the DSCT, cuneocerebellar tract, and the VSCT. The spino-olivary tract is a non-specific indirect ascending pathway and is connected to olivary nuclei. The axons enter the spinal cord from the

neg: Rostral ventromedial medulla and 70% P2Y1. Rostral ventromedial medulla The rostral ventromedial medulla (RVM), or ventromedial nucleus of the spinal cord, is a group of neurons located close to the midline on the floor of the medulla oblongata (myelencephalon). The rostral ventromedial medulla sends descending inhibitory and excitatory fibers to the dorsal horn spinal cord neurons. There are 3 categories of neurons in the RVM: on-cells, off-cells, and neutral cells. They are characterized by their response to nociceptive input. Off-cells show a transitory decrease in firing rate right before a nociceptive reflex, and are theorized to be inhibitory. Activation of off-cells, either by

neg: Rostral ventromedial medulla Rostral ventromedial medulla The rostral ventromedial medulla (RVM), or ventromedial nucleus of the spinal cord, is a group of neurons located close to the midline on the floor of the medulla oblongata (myelencephalon). The rostral ventromedial medulla sends descending inhibitory and excitatory fibers to the dorsal horn spinal cord neurons. There are 3 categories of neurons in the RVM: on-cells, off-cells, and neutral cells. They are characterized by their response to nociceptive input. Off-cells show a transitory decrease in firing rate right before a nociceptive reflex, and are theorized to be inhibitory. Activation of off-cells, either by morphine or by

neg: Pyramidal tracts the cruz cerebri (pedunculotomy). In National Lampoon's European Vacation, the Griswold family was asked about the pyramidal tracts on the game show "Pig in a Poke". Pyramidal tracts The pyramidal tracts include both the corticobulbar tract and the corticospinal tract. These are aggregations of efferent nerve fibers from the upper motor neurons that travel from the cerebral cortex and terminate either in the brainstem ("corticobulbar") or spinal cord ("corticospinal") and are involved in the control of motor functions of the body. The corticobulbar tract conducts impulses from the brain to the cranial nerves. These nerves control the muscles of the

neg: Gracile fasciculus below: First-order fibers: found on the ipsilateral side of the spinal cord; ends at the gracile nucleus in medulla oblongata of the brainstem. Second-order fibers: found in the medulla; decussate in the medulla as internal arcuate fibers and, together with the second-order fibers of the cuneate fasiculus, create nerve fiber tracts called the medial lemniscus, which relays the information received from the first-order neurons to the thalamus. Third-order fibers: fibers which relay the signal received from the medial lemniscus at the thalamus to the cerebral cortex. Damage to either of these tracts can result in the permanent loss of sensation

neg: Sexuality after spinal cord injury the sensation is reduced. The severity of the injury is an important aspect in determining how much sexual function returns as a person recovers. According to the American Spinal Injury Association grading scale, an incomplete SCI is one in which some amount of sensation or motor function is preserved in the rectum. This indicates that the brain can still send and receive some messages to the lowest parts of the spinal cord, beyond the damaged area. In people with incomplete injury, some or all of the spinal tracts involved in sexual responses remain intact, allowing, for example, orgasms like those

neg: Spinoreticular tract Spinoreticular tract The spinoreticular tract is an ascending pathway in the white matter of the spinal cord, positioned closely to the lateral spinothalamic tract. The tract is from spinal cord—to reticular formation— to thalamus. It is responsible for automatic responses to pain, such as in the case of injury. The spinoreticular tract utilizes four levels of neurons, unlike most ascending tracts which have first- through third-order neurons. The tract begins with first-order neurons, which immediately synapse with second-order neurons in the posterior horn of the spinal column. These neurons decussate to the opposite side (anterolateral), and travel up the spinal

neg: Allodynia interneurons, leading to the transmission of pain information by mechanoreceptors A different study reports the appearance of descending fibers at the injury site. All of these changes ultimately affect the circuitry inside the spinal cord, and the altered balance of signals probably leads to the intense sensation of pain associated with allodynia. Different cell types have also been linked to allodynia. For example, there are reports that microglia in the thalamus might contribute to allodynia by changing the properties of the secondary nociceptors. The same effect is achieved in the spinal cord by the recruitment of immune system cells such

neg: Stroke recovery result from alterations in the balance of inputs from reticulospinal and other descending pathways to the motor and interneuronal circuits of the spinal cord, and the absence of an intact corticospinal system. In other words, there is damage to the part of the brain or spinal cord that controls voluntary movement. Various means are available for the treatment of the effects of the upper motor neuron syndrome. These include: exercises to improve strength, control and endurance, nonpharmacologic therapies, oral drug therapy, intrathecal drug therapy, injections, and surgery. While Landau suggests that researchers do not believe that treating spasticity is worthwhile,

neg: Syrinx (medicine) up into the brainstem (syringobulbia). Syringobulbia, which is rare, usually occurs as a slitlike gap within the lower brain stem and may disrupt or compress the lower cranial nerves or ascending sensory or descending motor pathways. A syrinx is suggested by an unexplained central cord syndrome or other characteristic neurologic deficits, particularly pain and temperature sensory deficits in a capelike distribution. MRI of the entire spinal cord and brain is done. Administration of intravenous Gadolinium during the MRI examination is useful for detecting any associated tumor. Underlying problems (e.g. craniocervical junction abnormalities, postoperative scarring, spinal tumors) are corrected when possible.

neg: Upper motor neuron lesion syndrome. These changes vary depending on the site and the extent of the lesion, and may include: These are the neural tracts which descend in the ventral horn of the spinal cord, carrying signals for voluntary movement of skeletal muscle. From their origin in the primary motor cortex, these nerves pass via the corona radiata to gather in the internal capsule before crossing over to the opposite side (decussation) in the medullary pyramids and proceeding down the spinal cord to meet lower motor neurons in the anterior grey column. During an exam, your doctor will look for signs of a

neg: Alpha motor neuron caudal (i.e., towards the bottom) of the brainstem structures. In the spinal cord, α-MNs are located within the gray matter that forms the ventral horn. These α-MNs provide the motor component of the spinal nerves that innervate muscles of the body. As in the brainstem, higher segments of the spinal cord contain α-MNs that innervate muscles higher on the body. For example, the biceps brachii muscle, a muscle of the arm, is innervated by α-MNs in spinal cord segments C5, C6, and C7, which are found rostrally in the spinal cord. On the other hand, the gastrocnemius muscle, one of

neg: Nucleus proprius of spinal cord the substantia gelatinosa of Rolando are involved in sensing pain and temperature. Nucleus proprius of spinal cord The nucleus proprius is a layer of the spinal cord adjacent to the substantia gelatinosa. The nucleus proprius can be found in the gray matter in all levels of the spinal cord. It constitutes the first synapse of the spinothalamic tract carrying pain and temperature sensations from peripheral nerves. Cells in this nucleus project to deeper laminae of the spinal cord, to the posterior column nuclei, and to other supraspinal relay centers including the midbrain, thalamus, and hypothalamus. Rexed laminae III, IV, and

neg: Spinal interneuron way that the descending signal, which activates the contraction of one muscle, causes relaxation of the other muscles. The autogenic inhibition reflex is a spinal reflex phenomenon that involves the Golgi tendon organ. When tension is applied to a muscle, group Ib fibers that innervate the Golgi tendon organ are activated. These afferent fibers project onto the spinal cord and synapse with the spinal interneurons called Ib inhibitory interneurons. This spinal interneuron makes an inhibitory synapse onto the alpha motor neuron that innervates the same muscle that caused the Ib afferent to fire. As a result of this reflex, activation

neg: Pyramidal tracts "corticobulbar" tract are involved in movement in muscles of the head. They are involved in swallowing, phonation, and movements of the tongue. By virtue of involvement with the facial nerve, the corticobulbar tract is also responsible for transmitting facial expression. With the exception of lower muscles of facial expression, all functions of the corticobulbar tract involve inputs from both sides of the brain. The term "extrapyramidal motor system" is used to refer to tracts within the spinal cord involved in involuntary movement but not part of the pyramidal tracts. Their functions include the control of posture and muscle tone. If

neg: Neuromere spinal cord segments are found between vertebral levels T9 and L2, and the spinal cord ends around the L1/L2 vertebral level, forming a structure known as the conus medullaris. Although the spinal cord cell bodies end around the L1/L2 vertebral level, the spinal nerves for each segment exit at the level of the corresponding vertebra. For the nerves of the lower spinal cord, this means that they exit the vertebral column much lower (more caudally) than their roots. As these nerves travel from their respective roots to their point of exit from the vertebral column, the nerves of the lower

neg: Spinal tumor tumors is very difficult, mainly due to its symptoms, which tend to be wrongly attributed to more common and benign degenerative spinal diseases. Spinal cord compression is commonly found in patients with metastatic malignancy. Back pain is a primary symptom of spinal cord compression in patients with known malignancy. It may prompt a bone scan to confirm or exclude spinal metastasis. Rapid identification and intervention of malignant spinal tumors, often causing spinal cord compression, is key to maintaining quality of life in patients. Extradural tumors are mostly metastases from primary cancers elsewhere (commonly breast, prostate and lung cancer). Intradural tumours

neg: L1 family of the brain and the other that runs between the brain and the spinal cord. The absence of such nerve tracts suggests that L1 is involved in the growth of axons within the embryonic nervous system."** L1 family The L1 family is a family of cell adhesion molecules that includes four different L1-like proteins. They are members of the immunoglobulin superfamily (IgSF CAM). The members of the L1-family in humans are called L1 or L1cam, CHL1 (close homologue of L1), Neurofascin and NRCAM (NgCAM related cell adhesion molecule). L1 family members are found on neurons, especially on their axons. Sometimes

neg: Medial vestibular nucleus in the lateral medullary syndrome. Medial vestibular nucleus The medial vestibular nucleus is one of the vestibular nuclei. It is located in the medulla oblongata. Lateral vestibulo-spinal tract (lateral vestibular nucleus “Deiters”)- via ventrolateral medulla and spinal cord to ventral funiculus (lumbo-sacral segments). ..Ipsilaterally for posture Medial vestibulo-spinal tract (medial, lateral, inferior, vestibular nuclei), bilateral projection via descending medial longitudinal fasciculus to cervical segments. DESCENDING MLF..Bilaterally for head/neck/eye movements It is one of the nuclei that corresponds to CN VIII, corresponding to the vestibular nerve, which joins with the cochlear nerve. It receives its blood supply from the Posterior Inferior

neg: Nerve tract cerebrum to the spinal cord. Other projection tracts carry signals upward to the cerebral cortex. Superior to the brainstem, such tracts form a broad, dense sheet called the internal capsule between the thalamus and basal nuclei, then radiate in a diverging, fanlike array to specific areas of the cortex. Nerve tract A nerve tract is a bundle of nerve fibers (axons) connecting nuclei of the central nervous system. In the peripheral nervous system this is known as a nerve. The main nerve tracts in the central nervous system are of three types: association fibers, commissural fibers, and projection fibers. A

neg: Medial vestibular nucleus Medial vestibular nucleus The medial vestibular nucleus is one of the vestibular nuclei. It is located in the medulla oblongata. Lateral vestibulo-spinal tract (lateral vestibular nucleus “Deiters”)- via ventrolateral medulla and spinal cord to ventral funiculus (lumbo-sacral segments). ..Ipsilaterally for posture Medial vestibulo-spinal tract (medial, lateral, inferior, vestibular nuclei), bilateral projection via descending medial longitudinal fasciculus to cervical segments. DESCENDING MLF..Bilaterally for head/neck/eye movements It is one of the nuclei that corresponds to CN VIII, corresponding to the vestibular nerve, which joins with the cochlear nerve. It receives its blood supply from the Posterior Inferior Cerebellar Artery, which is compromised

neg: Aortic aneurysm closed around the graft. The aorta and its branching arteries are cross-clamped during open surgery. This can lead to inadequate blood supply to the spinal cord, resulting in paraplegia. A 2004 systematic review and meta analysis found that cerebrospinal fluid drainage (CFSD), when performed in experienced centers, reduces the risk of ischemic spinal cord injury by increasing the perfusion pressure to the spinal cord. A 2012 Cochrane systematic review noted that further research regarding the effectiveness of CFSD for preventing a spinal cord injury is required. Endovascular treatment of aortic aneurysms is a minimally invasive alternative to open surgery repair.

neg: Pathology of multiple sclerosis spinal cord has been found to be affected by MS even without attacks, and damage correlates with disability. In RRMS, cervical spinal cord activity is enhanced, to compensate for the damage of other tissues. It has been shown that Fractional anisotropy of cervical spinal cord is lower than normal, showing that there is damage hidden from normal MRI. Progressive tissue loss and injury occur in the cervical cord of MS patients. These two components of cord damage are not interrelated, suggesting that a multiparametric MRI approach is needed to get estimates of such a damage. MS cord pathology is independent

neg: Cranial nerve nucleus closer to the back (dorsal). This arrangement mirrors the arrangement of tracts in the spinal cord. This list documents nuclei by the part of the brain they are found in: Cranial nerve nucleus A cranial nerve nucleus is a collection of neurons (gray matter) in the brain stem that is associated with one or more cranial nerves. Axons carrying information to and from the cranial nerves form a synapse first at these nuclei. Lesions occurring at these nuclei can lead to effects resembling those seen by the severing of nerve(s) they are associated with. All the nuclei except that of

neg: Olfactory ensheathing glia mucosa, where neurons are directly exposed to the external environment. OEG have been tested successfully in experimental axonal regeneration in adult rats with traumatic spinal cord damage, and clinical trials are currently being conducted to obtain more information on spinal cord injuries and other neurodegenerative diseases. In the peripheral nervous system OEG are dispersed within the olfactory epithelium and the olfactory nerve. In the central nervous system, OEG are found within the outer two layers of the olfactory bulb. During development, primitive olfactory neurons extend their axons from the olfactory placode, through the mesenchyme, towards the telencephalic vesicle. After reaching

neg: Spinal cord Spinal cord The spinal cord is a long, thin, tubular structure made up of nervous tissue, that extends from the medulla oblongata in the brainstem to the lumbar region of the vertebral column. It encloses the central canal of the spinal cord that contains cerebrospinal fluid. The brain and spinal cord together make up the central nervous system (CNS). In humans, the spinal cord begins at the occipital bone where it passes through the foramen magnum, and meets and enters the spinal canal at the beginning of the cervical vertebrae. The spinal cord extends down to between the first and

neg: Hereditary diffuse leukoencephalopathy with spheroids has been shown that white matter abnormalities are relatively confined to the cerebrum while avoiding the cerebellum and many of the major fiber tracts of the nervous system. The exception is the corticospinal tracts(pyramidal tracts) in the brainstem and sometimes spinal cord. The brain pathology of HDLS resembles that of Nasu-Hakola disease (polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy). Research as of 2012 includes investigations of microglial function. This work would further clarify whether the disease is primarily a defect in microglia function. For such a study, microglial cells from HDLS kindred can be cultured from autopsy brain and analyzed in

neg: Allen Institute for Brain Science Since the project's launch, it has been renamed the Allen Mouse Brain Atlas to distinguish it from subsequent Atlas projects. On July 17, 2008, the Allen Institute for Brain Science launched the online "Allen Spinal Cord Atlas. The spinal cord atlas is an interactive, genome-wide map showing where each gene is expressed, or "turned on", throughout the mouse spinal cord. It is set up like the Allen Institute's earlier atlas of the adult mouse brain. The map could help reveal new treatments for human neurological disorders. The map points researchers toward places where genes are active The Allen Spinal Cord

neg: Human brain and association regions. Although the left and right hemispheres are broadly similar in shape and function, some functions are associated with one side, such as language in the left and visual-spatial ability in the right. The hemispheres are connected by commissural nerve tracts, the largest being the corpus callosum. The cerebrum is connected by the brainstem to the spinal cord. The brainstem consists of the midbrain, the pons, and the medulla oblongata. The cerebellum is connected to the brainstem by pairs of tracts. Within the cerebrum is the ventricular system, consisting of four interconnected ventricles in which cerebrospinal fluid is

neg: Motor neuron and along with the signals, determine whether a motor neuron will be more rostral or caudal in character. In the spinal column, Hox 4-11 sort motor neurons to one of the five motor columns. Upper motor neurons originate in the motor cortex located in the precentral gyrus. The cells that make up the primary motor cortex are Betz cells, which are a type of pyramidal cell. The axons of these cells descend from the cortex to form the corticospinal tract. Nerve tracts are bundles of axons as white matter, that carry action potentials to their effectors. In the spinal cord

neg: Endocannabinoid system cord, cannabinoids suppress noxious-stimulus-evoked responses of neurons in the dorsal horn, possibly by modulating descending noradrenaline input from the brainstem. As many of these fibers are primarily GABAergic, cannabinoid stimulation in the spinal column results in disinhibition that should increase noradrenaline release and attenuation of noxious-stimuli-processing in the periphery and dorsal root ganglion. The endocannabinoid most researched in pain is palmitoylethanolamide. Palmitoylethanolamide is a fatty amine related to anandamide, but saturated and although initially it was thought that palmitoylethanolamide would bind to the CB1 and the CB2 receptor, later it was found that the most important receptors are the PPAR-alpha

neg: Gamma motor neuron back to the brain and spinal cord are misleading. For example, if a patient has over active gamma motor neurons, there will be a resistance to passive movement causing stiffness, also called spasticity. This is often found in individuals with damage to higher centers affecting the descending pathways. This can sometimes cause a gamma-bias (constant discharge of some gamma motor neurons) to be greater or less than usual. In the case for patients with excess gamma bias, the sensory endings within muscle spindles are discharging too frequently causing there to be more muscle activity than appropriate. Furthermore, this hyperactivity in

neg: Spinal tumor cord compression. Spinal tumors are rare in pediatric patients with majority of diagnoses being made around 11 years of age. Spinal tumor Spinal tumors are neoplasms located in the spinal cord. Extradural tumors are more common than intradural neoplasms. Depending on their location, the spinal cord tumors can be: Pain is the most common symptom at presentation. The symptoms seen are due to spinal nerve compression and weakening of the vertebral structure. Incontinence and decreased sensitivity in the "saddle area" (buttocks) are generally considered warning signs of spinal cord compression by the tumor. Other symptoms of spinal cord compression include

neg: Nerve tract of the cingulate gyrus and links from this to the entorhinal cortex. Commissural tracts connect corresponding cortical areas in the two hemispheres. They cross from one cerebral hemisphere to the other through bridges called commissures. The great majority of commissural tracts pass through the corpus callosum. A few tracts pass through the much smaller anterior and posterior commissures. Commissural tracts enable the left and right sides of the cerebrum to communicate with each others. Projection tracts connect the cerebral cortex with the corpus striatum, diencephalon, brainstem and the spinal cord. The corticospinal tract for example, carries motor signals from the