Spinothalamic tract - wikipedia Spinothalamic tract Spinothalamic tract Spinothalamic tracts are grouped, in blue at bottom right. Diagram of the principal fasciculi of the spinal cord. ( Anterior and posterior spinothalamic fasciculus is labeled at bottom left. ) Details Identifiers Latin Tractus spinothalamicus MeSH D013133 NeuroNames 2058, 810 TA A14. 1.04. 138 FMA 72644 Anatomical terms of neuroanatomy ( edit on Wikidata ) The spinothalamic tract ( also known as anterolateral system or the ventrolateral system ) is a sensory pathway from the skin to the thalamus. From the ventral posterolateral nucleus in the thalamus, sensory information is relayed upward to the somatosensory cortex of the postcentral gyrus. The spinothalamic tract consists of two adjacent pathways : anterior and lateral. The anterior spinothalamic tract carries information about crude touch. The lateral spinothalamic tract conveys pain and temperature. In the spinal cord, the spinothalamic tract has somatotopic organization. This is the segmental organization of its cervical, thoracic, lumbar, and sacral components, which is arranged from most medial to most lateral respectively. The pathway decussates at the level of the spinal cord, rather than in the brainstem like the posterior column - medial lemniscus pathway and lateral corticospinal tract. Contents 1 Structure 2 Function 2.1 Anterolateral system 3 Clinical significance 4 See also 5 References Structure There are two main parts of the spinothalamic tract ( STT ) : The lateral spinothalamic tract transmits pain and temperature. The anterior spinothalamic tract ( or ventral spinothalamic tract ) transmits crude touch and firm pressure. The spinothalamic tract, like the dorsal column - medial lemniscus tract, uses three neurons to convey sensory information from the periphery to conscious level at the cerebral cortex. Pseudounipolar neurons in the dorsal root ganglion have axons that lead from the skin into the dorsal spinal cord where they ascend or descend one or two vertebral levels via Lissauer 's tract and then synapse with secondary neurons in either the substantia gelatinosa of Rolando or the nucleus proprius. These secondary neurons are called tract cells. The axons of the tract cells cross over ( decussate ) to the other side of the spinal cord via the anterior white commissure, and to the anterolateral corner of the spinal cord ( hence the spinothalamic tract being part of the anterolateral system ). Decussation usually occurs 1 - 2 spinal nerve segments above the point of entry. The axons travel up the length of the spinal cord into the brainstem, specifically the rostral ventromedial medulla. Traveling up the brainstem, the tract moves dorsally. The neurons ultimately synapse with third - order neurons in several nuclei of the thalamus -- including the medial dorsal, ventral posterior lateral, and ventral posterior medial nuclei. From there, signals go to the cingulate cortex, the primary somatosensory cortex, and insular cortex respectively. Function The types of sensory information transmitted via the spinothalamic tract are described as affective sensation. This means that the sensation is accompanied by a compulsion to act. For instance, an itch is accompanied by a need to scratch, and a painful stimulus makes us want to withdraw from the pain. There are two sub-systems identified : Direct ( for direct conscious appreciation of pain ) Indirect ( for affective and arousal impact of pain ). Indirect projections include Spino - Reticulo - Thalamo - Cortical ( part of the ascending reticular arousal system, aka ARAS ) Spino - Mesencephalic - Limbic ( for affective impact of pain ). Anterolateral system In the 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 : Name Destination Function spinothalamic tract ( lateral and anterior ) thalamus important in the localization of painful or thermal stimuli spinoreticular tract reticular formation causes alertness and arousal in response to painful stimuli spinotectal tract tectum orients the eyes and head towards the stimuli Clinical significance In contrast to the axons of second - order neurons in posterior 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 cord lesions, however, the deficit in pain perception is contralateral to the lesion, whereas the other deficits are ipsilateral. See Brown - Séquard syndrome. Unilateral lesions usually cause contralateral anaesthesia ( loss of pain and temperature ). Anaesthesia will normally begin 1 - 2 segments below the level of lesion, due to the sensory fibers being carried by dorsal - lateral tract of Lissauer up several levels upon entry into the spinal cord, and will affect all caudal body areas. This is clinically tested by using pin pricks. See also This article uses anatomical terminology ; for an overview, see Anatomical terminology. Rostral ventromedial medulla Periaqueductal gray Neothalamus References Jump up ^ `` Chapter 25 : Neural Mechanisms of Cardiac Pain : The Anterolateral System ''. Retrieved 2009 - 11 - 26. Sensory receptors Touch Mechanoreceptor Vibration Lamellar corpuscle Light touch Tactile corpuscle Pressure Merkel nerve ending Stretch Bulbous corpuscle Pain Free nerve ending Nociceptors Temperature Thermoreceptors Proprioception Golgi organ Muscle spindle Intrafusal muscle fiber Nuclear chain fiber Nuclear bag fiber Other Hair cells Baroreceptor The spinal cord General features Cervical enlargement Lumbar enlargement Conus medullaris Filum terminale Cauda equina Meninges Grey matter Posterior grey column Marginal nucleus Substantia gelatinosa of Rolando Nucleus proprius Spinal lamina V Spinal lamina VI Lateral grey column Intermediolateral nucleus Posterior thoracic nucleus Anterior grey column Interneuron Alpha motor neuron Onuf 's nucleus Gamma motor neuron Other Rexed laminae Central gelatinous substance Gray commissure Central canal Terminal ventricle White matter Sensory Posterior Posterior column - medial lemniscus pathway : Gracile Cuneate Lateral : Spinocerebellar dorsal ventral Spinothalamic lateral anterior Posterolateral Spinotectal Spinoreticular tract Spino - olivary tract Motor Lateral Corticospinal Lateral Extrapyramidal Rubrospinal Olivospinal Raphespinal Anterior Corticospinal Anterior Extrapyramidal Vestibulospinal Reticulospinal Tectospinal Both Anterior white commissure External features Ventral Anterior median fissure Anterolateral sulcus Dorsal Posterior median sulcus Posterolateral sulcus Anatomy of the medulla Grey matter Cranial nuclei afferent : Solitary nucleus tract Dorsal respiratory group Gustatory nucleus Vestibular nuclei Lateral Medial Inferior efferent : Hypoglossal nucleus Nucleus ambiguus Dorsal nucleus of vagus nerve Inferior salivatory nucleus Dorsal Gracile nucleus Cuneate nucleus Accessory cuneate nucleus Ventral Ventral respiratory group Arcuate nucleus of medulla Rostral ventromedial medulla Botzinger complex Pre-Bötzinger complex White matter Dorsal Sensory Sensory decussation Medial lemniscus Juxtarestiform body Ascending dorsal longitudinal fasciculus Medial longitudinal fasciculus Motor Descending dorsal longitudinal fasciculus Medial longitudinal fasciculus Ventral Descending tracts Olivocerebellar tract Rubro - olivary tract Surface Front Pyramid Anterior median fissure Anterolateral sulcus Olive Inferior olivary nucleus Back Posterior median sulcus Posterolateral sulcus Area postrema Vagal trigone Hypoglossal trigone Medial eminence Inferior cerebellar peduncle Grey Reticular formation Gigantocellular Parvocellular Ventral Lateral Paramedian Raphe nuclei Obscurus Magnus Pallidus Perihypoglossal nuclei Anatomy of the pons Dorsal / ( tegmentum ) Surface Cerebellopontine angle Superior medullary velum Sulcus limitans Medial eminence Facial colliculus White : Sensory Trapezoid body Trigeminal lemniscus Dorsal trigeminal tract Ventral trigeminal tract Medial lemniscus Lateral lemniscus Medial longitudinal fasciculus Vestibulo - oculomotor fibers Anterior trigeminothalamic tract Central tegmental tract White : Motor Inferior cerebellar peduncle Vestibulocerebellar tract Medial longitudinal fasciculus Vestibulospinal tract Medial vestibulospinal tract Lateral vestibulospinal tract Grey : Cranial nuclei afferent : GSA Trigeminal Principal Spinal Cochlear nucleus Dorsal Anterior Vestibular nuclei Superior efferent : SVE : Trigeminal motor nucleus Facial motor nucleus GSE : Abducens nucleus GVE : Superior salivary nucleus Inferior salivary nucleus Other Apneustic center Pneumotaxic center Parabrachial nuclei Subparabrachial nucleus Medial parabrachial nucleus Lateral parabrachial nucleus Superior olivary nucleus Locus coeruleus Ventral / ( base ) Grey Pontine nuclei White : Motor / descending Corticospinal tract Corticobulbar tract Corticopontine fibers MCP Pontocerebellar fibers Surface Basilar sulcus Other grey : Raphe / reticular Reticular formation Caudal Oral Tegmental Paramedian Raphe nuclei Median Anatomy of the midbrain Tectum ( Dorsal ) Surface Corpora quadrigemina : Inferior colliculus Brachium Superior colliculus Brachium Grey matter Pretectal area White : Sensory / ascending Spinotectal tract Central tegmental tract White : Motor / descending Tectospinal tract Peduncle ( Ventral ) Tegmentum White : Sensory / ascending Lemnisci Medial Lateral Ascending MLF Vestibulo - oculomotor fibers Spinothalamic tract Anterior trigeminothalamic tract Dentatothalamic tract White : Motor / descending Rubrospinal tract Rubro - olivary tract Descending MLF Grey : cranial nuclei GSA Mesencephalic - GSE Oculomotor nucleus, Trochlear nucleus - GVE Edinger -- Westphal nucleus Grey : other Periaqueductal gray Raphe nuclei dorsal Ventral tegmental area Rostromedial tegmental nucleus Pedunculopontine nucleus Red nucleus Rostral interstitial nucleus of medial longitudinal fasciculus Parabrachial area Interpeduncular nucleus Midbrain reticular formation Ventricular system Cerebral aqueduct Base White : Motor / descending Cerebral crus : Corticospinal tract Corticobulbar tract Corticopontine tract / Frontopontine fibers / Temporopontine fibers Grey : Substantia nigra Pars compacta Pars reticulata Surface Superior cerebellar peduncle Decussation Interpeduncular fossa Anatomy of the diencephalon of the human brain Epithalamus Surface Pineal gland Habenula Habenular trigone Habenular commissure Grey matter Pretectal area Habenular nuclei Subcommissural organ Thalamus Surface Stria medullaris of thalamus Thalamic reticular nucleus Taenia thalami Grey matter / nuclei paired : AN Ventral VA / VL VP / VPM / VPL Lateral LD LP Pulvinar nuclei Metathalamus MG LG P cell M cell K cell midline : MD Intralaminar Centromedian Midline nuclear group Interthalamic adhesion White matter Mammillothalamic fasciculus Pallidothalamic tracts Ansa lenticularis Lenticular fasciculus Thalamic fasciculus PCML Medial lemniscus Trigeminal lemniscus Spinothalamic tract Lateral lemniscus Dentatothalamic tract Acoustic radiation Optic radiation Subthalamic fasciculus Anterior trigeminothalamic tract Medullary laminae Hypothalamus Surface Median eminence / Tuber cinereum Mammillary body Infundibulum Grey matter Autonomic zones Anterior ( parasympathetic / heat loss ) Posterior ( sympathetic / heat conservation ) Endocrine posterior pituitary : Paraventricular Magnocellular neurosecretory cell Parvocellular neurosecretory cell Supraoptic oxytocin / vasopressin other : Arcuate ( dopamine / GHRH ) Preoptic ( GnRH ) Suprachiasmatic ( melatonin ) Emotion Lateral Ventromedial Dorsomedial White matter afferent Medial forebrain bundle Retinohypothalamic tract efferent Mammillothalamic fasciculus Stria terminalis Dorsal longitudinal fasciculus Pituitary Posterior is diencephalon, but anterior is glandular Subthalamus Subthalamic nucleus Zona incerta Nuclei campi perizonalis ( Fields of Forel ) Brain and spinal cord : neural tracts and fasciculi Sensory / ascending PCML 1 ° : Pacinian corpuscle / Meissner 's corpuscle → Posterior column ( Gracile fasciculus / Cuneate fasciculus ) → Gracile nucleus / Cuneate nucleus 2 ° : → sensory decussation / arcuate fibers ( Posterior external arcuate fibers, Internal arcuate fibers ) → Medial lemniscus / Trigeminal lemniscus → Thalamus ( VPL, VPM ) 3 ° : → Posterior limb of internal capsule → Postcentral gyrus Anterolateral / pain Fast / lateral 1 ° ( Free nerve ending → A delta fiber ) → 2 ° ( Anterior white commissure → Lateral and Anterior Spinothalamic tract → Spinal lemniscus → VPL of Thalamus ) → 3 ° ( Postcentral gyrus ) → 4 ° ( Posterior parietal cortex ) 2 ° ( Spinomesencephalic tract → Superior colliculus of Midbrain tectum ) Slow / medial 1 ° ( Group C nerve fiber → Spinoreticular tract → Reticular formation ) → 2 ° ( MD of Thalamus ) → 3 ° ( Cingulate cortex ) Motor / descending Pyramidal flexion : Primary motor cortex → Posterior limb of internal capsule → Decussation of pyramids → Corticospinal tract ( Lateral, Anterior ) → Neuromuscular junction Extrapyramidal flexion : Primary motor cortex → Genu of internal capsule → Corticobulbar tract → Facial motor nucleus → Facial muscles flexion : Red nucleus → Rubrospinal tract extension : Vestibulocerebellum → Vestibular nuclei → Vestibulospinal tract extension : Vestibulocerebellum → Reticular formation → Reticulospinal tract Midbrain tectum → Tectospinal tract → muscles of neck Basal ganglia direct : 1 ° ( Motor cortex → Striatum ) → 2 ° ( GPi ) → 3 ° ( Lenticular fasciculus / Ansa lenticularis → Thalamic fasciculus → VL of Thalamus ) → 4 ° ( Thalamocortical radiations → Supplementary motor area ) → 5 ° ( Motor cortex ) indirect : 1 ° ( Motor cortex → Striatum ) → 2 ° ( GPe ) → 3 ° ( Subthalamic fasciculus → Subthalamic nucleus ) → 4 ° ( Subthalamic fasciculus → GPi ) → 5 ° ( Lenticular fasciculus / Ansa lenticularis → Thalamic fasciculus → VL of Thalamus ) → 6 ° ( Thalamocortical radiations → Supplementary motor area ) → 7 ° ( Motor cortex ) nigrostriatal pathway : Pars compacta → Striatum Cerebellar Afferent Vestibular nuclei → Vestibulocerebellar tract → ICP → Cerebellum → Granule cell Pontine nuclei → Pontocerebellar fibers → MCP → Deep cerebellar nuclei → Granule cell Inferior olivary nucleus → Olivocerebellar tract → ICP → Hemisphere → Purkinje cell → Deep cerebellar nuclei Efferent Dentate nucleus in Lateral hemisphere / pontocerebellum → SCP → Dentatothalamic tract → Thalamus ( VL ) → Motor cortex Interposed nucleus in Intermediate hemisphere / spinocerebellum → SCP → Reticular formation, or → Cerebellothalamic tract → Red nucleus → Thalamus ( VL ) → Motor cortex Fastigial nucleus in Flocculonodular lobe / vestibulocerebellum → Vestibulocerebellar tract → Vestibular nuclei Bidirectional : Spinocerebellar Unconscious proprioception lower limb → 1 ° ( muscle spindles → DRG ) → 2 ° ( Posterior thoracic nucleus → Dorsal / posterior spinocerebellar tract → ICP → Cerebellar vermis ) upper limb → 1 ° ( muscle spindles → DRG ) → 2 ° ( Accessory cuneate nucleus → Cuneocerebellar tract → ICP → Anterior lobe of cerebellum ) Reflex arc lower limb → 1 ° ( Golgi tendon organ ) → 2 ° ( Ventral / anterior spinocerebellar tract → SCP → Cerebellar vermis ) upper limb → 1 ° ( Golgi tendon organ ) → 2 ° ( Rostral spinocerebellar tract → ICP → Cerebellum ) Retrieved from `` https://en.wikipedia.org/w/index.php?title=Spinothalamic_tract&oldid=835162404 '' Categories : Spinal cord tracts Sensory systems Thalamic connections Hidden categories : Pages with unresolved properties All articles with unsourced statements Articles with unsourced statements from November 2016 Talk Contents About Wikipedia Español فارسی Français Italiano 日本 語 Polski Português ไทย 中文 Edit links This page was last edited on 6 April 2018, at 23 : 07. 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Question: where does decussation occur in the spinothalamic pathway
Answer: usually occurs 1-2 spinal nerve segments above the point of entry; 1-2 spinal nerve segments above the point of entry; 1-2 spinal nerve segments above the point of entry; 1-2 spinal nerve segments above the point of entry