Medial lemniscus

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Brain: Medial lemniscus
The sensory tract. (Medial lemniscus labeled at center right.)
Coronal section through mid-brain. ("e" is Portion of medial lemniscus, which runs to the lentiform nucleus and insula.)
Latin	lemniscus medialis
Gray's	subject #188 803
Part of
Components
Artery
Vein
BrainInfo/UW	ancil-736
MeSH	[1]

The medial lemniscus, also known as Reil's band or Reil's ribbon, is a pathway in the brainstem that carries sensory information from the gracile and cuneate nuclei to the thalamus. It forms part og the lemniscal system

Contents 1 Path 2 Location of the medial lemniscus through the brainstem 3 See also 4 Additional images 5 External links

[edit] Path

After neurons carrying proprioceptive or touch information synapse at the gracile and cuneate nuclei, axons from secondary neurons decussate at the level of the medulla and travel up the brainstem as the medial lemniscus on the contralateral (opposite) side. It is part of the posterior column-medial lemniscus system, which transmits touch, vibration sense, as well as the pathway for proprioception.

The medial lemniscus axons from most of the body synapse at the ventral posterolateral nucleus of the thalamus. The axons transmitting information from the trigeminal nerve synapse at the ventral posteromedial nucleus of the thalamus.

[edit] Location of the medial lemniscus through the brainstem

• The cuneate and gracile nuclei reside at the closed (lower) medulla, so the lemniscus isn't formed at this level. Fibres from these nuclei will pass to the contralateral side of the brainstem, as the internal arcuate fibres.

• At the open medulla (further up the brainstem), the medial lemniscus contains axons from the trigeminal nerve (which supplies the head region), as well as the arms and legs. It sits very close to the midline, at the same orientation of the midline, with head fibres more dorsal (closer to the back), towards the fourth ventricle.

• By mid-pons, the medial lemniscus has rotated. Fibres from the head are medial, fibres from the leg are lateral.

• The orientation in the midbrain is similar to that in the pons.

[edit] See also

• Posterior column-medial lemniscus pathway

[edit] Additional images

Deep dissection of brain-stem. Lateral view.	Deep dissection of brain-stem. Ventral view.	Coronal section of the pons, at its upper part.	Transverse section of mid-brain at level of inferior colliculi.
Scheme showing the course of the fibers of the lemniscus; medial lemniscus in blue, lateral in red.

[edit] External links

• Brainstem at UWisc 04NGNC
• BrainMaps at UCDavis medial%20lemniscus

v·d·e Brain: rhombencephalon (hindbrain)
Metencephalon/ pons	{| class="navbox collapsible nowraplinks" style="margin:auto; background:white;background:white;"
[[[:Template:Fullurl:Template:]] v]·[[[:Template:Fullurl:Template talk:]] d]·[[[:Template:Fullurl:Template:]] e]
Dorsal/ (tegmentum)	surface: Locus ceruleus Trigeminal lemniscus (Dorsal trigeminal tract, Ventral trigeminal tract) cranial nuclei: GSA: Principal V/Spinal V - VIII-c (Dorsal, Anterior)/VIII-v (Lateral, Superior, Medial, Inferior) - SVE: Motor V - VII - GSE: VI - GVE: VII: Superior salivary nucleus MLF, III, IV and VI (vestibulo-oculomotor fibers, medial vestibulospinal tract) sensory/ascending: Trapezoid body/VIII - Superior olivary nucleus Inferior cerebellar peduncle (Vestibulocerebellar tract) motor/descending: Apneustic center • Pneumotaxic center (Medial parabrachial nucleus) - Lateral parabrachial nucleus
Ventral/ (base)	Middle cerebellar peduncles (Pontocerebellar fibers) - Pontine nuclei motor/descending: Corticospinal tract - Corticobulbar tract - Corticopontine fibers
Raphe/reticular	Reticular formation (Caudal, Oral, Tegmental, Paramedian) • Raphe nuclei (Median)

|- style="white-space:nowrap;background:#ddddff;text-align:right;background-color: LightYellow" ! Myelencephalon/
medulla | colspan="1" style="text-align:left;width:100%;font-size:95%;background:#f7f7f7;" | {| class="navbox collapsible nowraplinks" style="margin:auto; background:white;background:white;" |- style="text-align:center;width:100%;"

!colspan="2" |

|- |- style="white-space:nowrap;background:#ddddff;text-align:right;padding-left:0em;padding-right:0em;background-color: LightYellow"

!

| colspan="1" style="text-align:left;width:100%;font-size:95%;" | surface: Posterior median sulcus - Postero-lateral sulcus - Area postrema

cranial nuclei: GVA: VII,IX,X: Solitary/tract • SVA: Gustatory nucleus • GSE: XII  • GVE: IX,X,XI: Ambiguus • SVE: X: Dorsal • IX: Inferior salivatory nucleus - MLF, III, IV and VI

sensory/ascending: Gracile nucleus • Cuneate nucleus (Accessory cuneate nucleus) • Sensory decussation  • Medial lemniscus

motor/descending: Dorsal respiratory group
|- style="white-space:nowrap;background:#ddddff;text-align:right;padding-left:0em;padding-right:0em;background-color: LightYellow"

!

| colspan="1" style="text-align:left;width:100%;font-size:95%;background:#f7f7f7;" | motor/descending: Ventral respiratory group - Pyramid (Motor decussation) - Inferior olivary nucleus (Olivocerebellar tract, Rubro-olivary tract)
surface: Anterior median fissure - Antero-lateral sulcus - Arcuate nucleus of medulla - Olivary body
|- style="white-space:nowrap;background:#ddddff;text-align:right;padding-left:0em;padding-right:0em;background-color: LightYellow"

!

| colspan="1" style="text-align:left;width:100%;font-size:95%;" | Reticular formation (Gigantocellular, Parvocellular, Ventral, Lateral, Paramedian) • Raphe nuclei (Obscurus, Magnus, Pallidus) |} |}

Mesencephalon (midbrain)

cerebral peduncle: midbrain tegmentum (periaqueductal gray, ventral tegmentum, nucleus raphe dorsalis), pretectum, substantia nigra, red nucleus, pedunculopontine nucleus, medial longitudinal fasciculus, medial lemniscus, rubrospinal tract, lateral lemniscus tectum: corpora quadrigemina, inferior colliculi, superior colliculi cerebral aqueduct: oculomotor nucleus, trochlear nucleus, Edinger-Westphal nucleus

This box: view • talk • edit Nervous system, receptors: somatosensory system
Medial lemniscus: Touch/mechanoreceptors: Pacinian corpuscles - Meissner's corpuscles - Merkel's discs - Ruffini endings - Free nerve endings - Hair cells - Baroreceptor Proprioception: Golgi organ - Muscle spindle (Intrafusal muscle fiber) Spinothalamic tract: Pain: Nociceptors Temperature: Thermoreceptors

This page uses content from the English-language version of Wikipedia. The original article was at Medial lemniscus. The list of authors can be seen in the page history. As with Psychology Wiki, the text of Wikipedia is available under the GNU Free Documentation License.