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| Medial longitudinal fasciculus |
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Transverse section of mid-brain at level of inferior colliculi. (Medial longitudinal fasciculus labeled at center right.)
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Axial section through mid-brain.
1. Corpora quadrigemina.
2. Cerebral aqueduct.
3. Central gray stratum.
4. Interpeduncular space.
5. Sulcus lateralis.
6. Substantia nigra.
7. Red nucleus of tegmentum.
8. Oculomotor nerve, with 8’, its nucleus of origin. a. Lemniscus (in blue) with a’ the medial lemniscus and a" the lateral lemniscus. b. Medial longitudinal fasciculus. c. Raphé. d. Temporopontine fibers. e. Portion of medial lemniscus, which runs to the lentiform nucleus and insula. f. Cerebrospinal fibers. g. Frontopontine fibers. |
| Details |
| Latin |
fasciculus longitudinalis medialis |
| Identifiers |
| Gray's |
p.803 |
| NeuroNames |
ancil-743 |
| NeuroLex ID |
Medial longitudinal fasciculus |
Dorlands
/Elsevier |
f_03/12356052 |
| TA |
A14.1.04.113
A14.1.05.304 |
| FMA |
72618 |
| Anatomical terms of neuroanatomy |
The medial longitudinal fasciculus (MLF) is one of a pair of crossed fiber tracts (group of axons), on each side of the brainstem. These bundles of axons are situated near the midline of the brainstem and are composed of both ascending and descending fibers that arise from a number of sources and terminate in different areas. MLF is the main central connection for the oculomotor nerve, trochlear nerve, and abducens nerve. The vertical gaze center is at the rostral interstitial nucleus (riMLF).
The MLF ascends to the interstitial nucleus of Cajal, which lies in the lateral wall of the third ventricle, just above the cerebral aqueduct.
Contents
- 1 Function
- 2 Clinical significance
- 3 Inputs
- 4 History
- 5 Additional images
- 6 See also
- 7 References
- 8 External links
Function
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 and upper limbs.
Clinical significance
A lesion of the MLF produces slowed or absent adduction of the ipsilateral eye, usually associated with involuntary jerky eye movements (nystagmus) of the abducting eye, a syndrome called internuclear ophthalmoplegia. Because multiple sclerosis causes de-myelination of the axons of CNS, it can cause internuclear ophthalmoplegia when MLF axons get de-myelinated,[1] where it presents as nystagmus and diplopia.
Inputs
The descending MLF mainly arises from the Superior-medial Vestibular nucleus (VN) and is thought to be involved in the maintenance of gaze reflex (stimulated by input form Semicircular canal). This is achieved by inputs to the VN from:
- the Vestibulocochlear (8th cranial) nerve about head movements,
- gait adjustments from the flocculus of the cerebellum,
- head and neck propioceptors and foot and ankle muscle spindle, via the fastigial nucleus.
Descending fibers can also arise from the superior colliculus in the rostral midbrain for visual reflexes, the accessory occulomotor nuclei in the rostral midbrain for visual tracking, and the pontine reticular formation, which facilitates extensor muscle tone. Ascending tracts arise from the Vestibular nucleus (VN) and terminate in the III, IV and VI nuclei, which are important for visual tracking.
History
In 1846 neurologist Benedict Stilling first referred to what is now known as the MLF as the acusticus, followed by Theodor Meynert in 1872 calling it posterior. But in 1891, Heinrich Schutz chose the name dorsal to describe the longitudinal bundle, "for brevity's sake". This name stuck despite other authors attempting further renaming (Ramon y Cajal's periependymal in 1904, Theodor Ziehen's nubecula dorsalis in 1913). But finally, it was Wilhelm His, Sr. who changed the name to medial for the sake of the Basle nomenclature to end the confusion.[citation needed]
Additional images
-
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Transverse section of medulla oblongata below the middle of the olive.
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Horizontal section through the lower part of the pons. The medial longitudinal fasciculus is labeled #6.
See also
Listing's law
References
- ^ Multiple Sclerosis Encyclopaedia
External links
- Atlas image: n2a4p4 at the University of Michigan Health System - "Brainstem, Cranial Nerve Nuclei, Sagittal Section, Medial View"
- http://isc.temple.edu/neuroanatomy/lab/atlas/papc/
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Anatomy of the medulla
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| Grey matter |
| Cranial nuclei |
| afferent: |
- Solitary nucleus
- tract
- Dorsal respiratory group
- Gustatory nucleus
- Vestibular nuclei
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| efferent: |
- Hypoglossal nucleus
- Nucleus ambiguus
- Dorsal nucleus of vagus nerve
- Inferior salivatory nucleus
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| Dorsal |
- Gracile nucleus
- Cuneate nucleus
- Accessory cuneate nucleus
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| Ventral |
-
- Ventral respiratory group
- Arcuate nucleus of medulla
- Rostral ventromedial medulla
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|
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| 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
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|
| Ventral |
- Descending tracts
- Olivocerebellar tract
- Rubro-olivary tract
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|
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| Surface |
| Front |
- Pyramid
- decussation
- Anterior median fissure
- Anterolateral sulcus
- Olive
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| Back |
- Posterior median sulcus
- Posterolateral sulcus
- Area postrema
- Vagal trigone
- Hypoglossal trigone
- Medial eminence
- Inferior cerebellar peduncle
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| Grey |
- Reticular formation
- Gigantocellular
- Parvocellular
- Ventral
- Lateral
- Paramedian
- Raphe nuclei
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Index of the central nervous system
|
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| Description |
- Anatomy
- meninges
- cortex
- association fibers
- commissural fibers
- lateral ventricles
- basal ganglia
- diencephalon
- mesencephalon
- pons
- cerebellum
- medulla
- spinal cord
- Physiology
- Development
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| Disease |
- Cerebral palsy
- Meningitis
- Demyelinating diseases
- Seizures and epilepsy
- Headache
- Stroke
- Sleep
- Congenital
- Injury
- Neoplasms and cancer
- Other
- Symptoms and signs
- head and neck
- eponymous
- lesions
- Tests
|
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| Treatment |
- Procedures
- Drugs
- general anesthetics
- analgesics
- addiction
- epilepsy
- cholinergics
- migraine
- Parkinson's
- vertigo
- other
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Anatomy of the pons
|
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Dorsal/
(tegmentum) |
| Surface |
- Cerebellopontine angle
- Superior medullary velum
- Sulcus limitans
- Medial eminence
- Facial colliculus
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|
| 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
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| White: Motor |
- Inferior cerebellar peduncle
- Vestibulocerebellar tract
- Medial longitudinal fasciculus
- Vestibulospinal tract
- Medial vestibulospinal tract
- Lateral vestibulospinal tract
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| Grey: Cranial nuclei |
| afferent: |
- GSA
- Cochlear nucleus
- Vestibular nuclei
|
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| efferent: |
- SVE: Trigeminal motor nucleus
- Facial motor nucleus
- GSE: Abducens nucleus
- GVE: Superior salivary nucleus
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| Other |
- Apneustic center
- Pneumotaxic center
- Medial parabrachial nucleus
- Lateral parabrachial nucleus
- Superior olivary nucleus
- Caerulean nucleus
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Ventral/
(base) |
| Grey |
|
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| White: Motor/descending |
- Corticospinal tract
- Corticobulbar tract
- Corticopontine fibers
- MCP
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| Surface |
|
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Other grey: Raphe/
reticular |
- Reticular formation
- Caudal
- Oral
- Tegmental
- Paramedian
- Raphe nuclei
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|
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Index of the central nervous system
|
|
| Description |
- Anatomy
- meninges
- cortex
- association fibers
- commissural fibers
- lateral ventricles
- basal ganglia
- diencephalon
- mesencephalon
- pons
- cerebellum
- medulla
- spinal cord
- Physiology
- Development
|
|
| Disease |
- Cerebral palsy
- Meningitis
- Demyelinating diseases
- Seizures and epilepsy
- Headache
- Stroke
- Sleep
- Congenital
- Injury
- Neoplasms and cancer
- Other
- Symptoms and signs
- head and neck
- eponymous
- lesions
- Tests
|
|
| Treatment |
- Procedures
- Drugs
- general anesthetics
- analgesics
- addiction
- epilepsy
- cholinergics
- migraine
- Parkinson's
- vertigo
- other
|
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Anatomy of the midbrain
|
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Tectum
(Dorsal) |
| Surface |
- Corpora quadrigemina:
- Inferior colliculus
- Superior colliculus
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| Grey matter |
|
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| White: Sensory/ascending |
- Spinotectal tract
- Central tegmental tract
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| White: Motor/descending |
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Peduncle
(Ventral) |
| Tegmentum |
| White: Sensory/ascending |
- Lemnisci
- Ascending MLF
- Vestibulo-oculomotor fibers
- Spinothalamic tract
- Anterior trigeminothalamic tract
- Dentatothalamic tract
|
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| White: Motor/descending |
- Rubrospinal tract
- Rubro-olivary tract
- Descending MLF
|
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| Grey: cranial nuclei |
- GSA
- Mesencephalic- GSE
- Oculomotor nucleus, Trochlear nucleus- GVE
- Edinger–Westphal nucleus
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| Grey: other |
- Periaqueductal gray
- Raphe nuclei
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- Ventral tegmental area
- Pedunculopontine nucleus
- Red nucleus
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- Rostral interstitial nucleus of medial longitudinal fasciculus
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| Ventricular system |
|
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| Base |
| White: Motor/descending |
- Cerebral crus: Corticospinal tract
- Corticobulbar tract
- Corticopontine tract/Frontopontine fibers/Temporopontine fibers
|
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| Grey: Substantia nigra |
- Pars compacta
- Pars reticulata
|
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| Surface |
- Superior cerebellar peduncle
- Interpeduncular fossa
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|
|
|
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Index of the central nervous system
|
|
| Description |
- Anatomy
- meninges
- cortex
- association fibers
- commissural fibers
- lateral ventricles
- basal ganglia
- diencephalon
- mesencephalon
- pons
- cerebellum
- medulla
- spinal cord
- Physiology
- Development
|
|
| Disease |
- Cerebral palsy
- Meningitis
- Demyelinating diseases
- Seizures and epilepsy
- Headache
- Stroke
- Sleep
- Congenital
- Injury
- Neoplasms and cancer
- Other
- Symptoms and signs
- head and neck
- eponymous
- lesions
- Tests
|
|
| Treatment |
- Procedures
- Drugs
- general anesthetics
- analgesics
- addiction
- epilepsy
- cholinergics
- migraine
- Parkinson's
- vertigo
- other
|
|
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Sensory system: Visual system and eye movement pathways
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| Visual perception |
- 1° (Retina bipolar cell) → 2° (Ganglionic cell) → 3° (Optic nerve → Optic chiasm → Optic tract → LGN of Thalamus) → 4° (Optic radiation → Cuneus and Lingual gyrus of Visual cortex → Blobs → Globs)
|
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| Muscles of orbit |
| Tracking |
| Smooth pursuit: |
- Parietal lobe
- Occipital lobe
|
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| Saccade: |
|
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- Nystagmus → Fixation reflex → PPRF
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|
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| Horizontal gaze |
- PPRF → Abducens nucleus → MLF → Oculomotor nucleus → Medial rectus muscle
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| Vertical gaze |
- Rostral interstitial nucleus → Oculomotor nucleus, Trochlear nucleus → Muscles of orbit
|
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| Vestibulo–ocular reflex |
- Semicircular canal → Vestibulocochlear nerve → Vestibular nuclei → Abducens nucleus → MLF (Vestibulo-oculomotor fibers) → Oculomotor nucleus → Medial rectus muscle
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|
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| Pupillary reflex |
| Pupillary response |
- 1° (Posterior hypothalamus → Ciliospinal center) → 2° (Superior cervical ganglion) → 3° (Sympathetic root of ciliary ganglion → Nasociliary nerve → Long ciliary nerves → Iris dilator muscle)
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Pupillary light reflex
(constriction) |
- 1° (Retina → Optic nerve → Optic chiasm → Optic tract → Pretectal nucleus) → 2° (Edinger–Westphal nucleus) → 3° (Oculomotor nerve → Parasympathetic root of ciliary ganglion → Ciliary ganglion) → (4° Short ciliary nerves → Iris sphincter muscle)
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Accommodation
vergence |
- 1° (Retina → Optic nerve → Optic chiasm → Optic tract → Visual cortex → Brodmann area 19 → Pretectal area) → 2° (Edinger–Westphal nucleus) → 3° (Short ciliary nerves → Ciliary ganglion → Ciliary muscle)
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| Circadian rhythm |
- Retina → Retinohypothalamic tract → Hypothalamus (Suprachiasmatic nucleus)
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Index of the eye
|
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| Description |
- Anatomy
- Physiology
- Phenomena
- appearance
- visual
- optical illusions
- proteins
- Development
|
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| Disease |
- Congenital
- Corneal dystrophy
- Neoplasms and cancer
- Other
- Symptoms and signs
|
|
| Treatment |
- Procedures
- Drugs
- infection
- glaucoma and miosis
- mydriatics
- vascular
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