Reticulospinal tract

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Brain: Reticulospinal tract
Reticulospinal tract is 2b, in red, near center.
NeuroNames	hier-802
Dorlands/Elsevier	t_15/12817131

The reticulospinal tract (or anterior reticulospinal tract) is an extrapyramidal motor tract which travels from the reticular formation.

[edit] Components

The sensory tract conveying information in the opposite direction is known as the "spinoreticular tract".

The tract is divided into two parts, the medial (or pontine) and lateral (or medullary) reticulospinal tracts (MRST and LRST).

• The MRST is caudal to the Superior Colliculus and is responsible for extensor muscles. The fibers of this tract arise from the caudal pontine reticular nucleus and the oral pontine reticular nucleus and project to the lamina VII and lamina VIII of the spinal cord (BrainInfo)

• The LRST is rostral to the Superior Colliculus and is responsible for the flexor muscles. The fibers of this tract arise from the medullary reticular formation, mostly from the gigantocellular nucleus, and descend the length of the spinal cord in the anterior part of the lateral column. The tract terminates in the gray spinal laminae (BrainInfo).

[edit] Clinical significance

If the superior colliculus is damaged, it is called decerebration and causes decerebate rigidity.

The reticulospinal tracts also provide a pathway by which the hypothalamus can control sympathetic thoracolumbar outflow and parasympathetic sacral outflow.

[edit] External links

• BrainInfo reticulospinal tract[1], pontine reticulospinal tract [2], and medullary reticulospinal tract[3]</a>.
• http://www.lib.mcg.edu/edu/eshuphysio/program/section8/8ch6/s8ch6_29.htm
• http://www.mona.uwi.edu/fpas/courses/physiology/neurophysiology/The%20Reticulospinal%20Pathway.htm

v • d • e Anatomy of torso (primarily): the spinal cord Spinal nerve Dorsal (Root, Ganglion, Ramus) • Ventral (Root, Ramus) • Sympathetic trunk • rami communicantes (Gray, White) Gray matter/Rexed laminae Posterior horn (Posteromarginal nucleus, Column of Clarke, Substantia gelatinosa of Rolando, Nucleus proprius) Lateral horn/Anterior horn (Intermediolateral nucleus) Central canal/Substantia gelatinosa centralis - Gray commissure White matter somatic/ascending (blue) Posterior/PCML: touch: Gracilis • Cuneatus Lateral: proprioception: Spinocerebellar (Dorsal, Ventral) • pain/temp: Spinothalamic (Lateral, Anterior) • Posterolateral (Lissauer) • Spinotectal motor/descending (red) Lateral: Corticospinal (Lateral) • Ep (Rubrospinal, Olivospinal) Anterior: Corticospinal (Anterior) • Ep (Vestibulospinal, Reticulospinal, Tectospinal) Layers Epidural space • Dura mater • Subdural space • Arachnoid mater • Subarachnoid space • Pia mater Other structures Denticulate ligaments • Conus medullaris • Cauda equina • Filum terminale • Cervical enlargement • Lumbar enlargement Anterior median fissure • Posterior median sulcus Anterior white commissure

v • d • e Brain: reticular formation Medial reticular formation Gigantocellular - Caudal pontine - Oral pontine - Parvocellular - Ventral Lateral reticular formation Lateral - Paramedian - Tegmental pontine Tracts Reticulospinal tract

v • d • e Brain and spinal cord: neural tracts and fasciculi Sensory/ascending: PCML Pacinian corpuscle/Meissner's corpuscle → PCML → arcuate fibers (Posterior external arcuate fibers, Internal arcuate fibers) - Medial lemniscus → Thalamus → Postcentral gyrus Sensory/ascending: anterolateral system Free nerve ending → Spinothalamic tract (Lateral, Anterior) → Spinal lemniscus → Postcentral gyrus Spinoreticular tract → Reticular formation Spinotectal tract → Midbrain tectum Motor/descending: pyramidal and extrapyramidal flexion: Primary motor cortex → Posterior limb of internal capsule → Decussation of the pyramids → Corticospinal tract (Lateral, Anterior) → Neuromuscular junction flexion: Red nucleus → Rubrospinal tract extension: Vestibulocerebellum → Vestibular nuclei → Vestibulospinal tract extension: Vestibulocerebellum → Reticular formation → Reticulospinal tract Midbrain tectum → Tectospinal tract → muscles of neck Bidirectional: Spinocerebellar Unconscious proprioception: Golgi tendon organ → Spinocerebellar (Dorsal/Dorsal nucleus of Clarke/Column of Clarke, Cuneocerebellar) → Cerebellum Reflex arc: Ventral - Rostral Brain only Medial longitudinal fasciculus Vestibular nucleus → Vestibulocerebellar tract → Cerebellum Pontine nuclei → Pontocerebellar fibers → Deep cerebellar nuclei Inferior olivary nucleus → Olivocerebellar tract → Cerebellar hemisphere Primary motor cortex → Genu of internal capsule → Corticobulbar tract → brainstem see also white matter fibers