Ventral trigeminal tract

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Ventral trigeminal tract
Details
System Sensory system
Fromhead, face, and oral cavity via principal (chief sensory) nucleus and spinal trigeminal nucleus
To ventral posteromedial (VPM) nucleus of the thalamus
Functioncarry sensory information about discriminative and crude touch, conscious proprioception, pain, and temperature from the head, face, and oral cavity
Identifiers
Latin tractus trigeminalis ventralis
NeuroNames 613
TA98 A14.1.05.311
TA2 5863
FMA 72506
Anatomical terms of neuroanatomy

The ventral trigeminal tract, ventral trigeminothalamic tract, anterior trigeminal tract, or anterior trigeminothalamic tract, is a tract composed of second-order neuronal axons. These afferent fibers carry sensory information about discriminative and crude touch, conscious proprioception, pain, and temperature from the head, face, and oral cavity. The ventral trigeminal tract connects the two major components of the brainstem trigeminal complex – the principal, or main sensory nucleus and the spinal trigeminal nucleus, to the ventral posteromedial nucleus of the thalamus. [1]

Contents

The ventral trigeminal tract is also called the anterior trigeminal lemniscus. [2]

Structure

The first-order neurons from the trigeminal ganglion enter the pons and synapse in the principal (chief sensory) nucleus or spinal trigeminal nucleus. Axons of the second-order neurons cross the midline and terminate in the ventral posteromedial nucleus of the contralateral thalamus (as opposed to the ventral posterolateral nucleus, as in the dorsal column medial lemniscus (DCML) system). The third order neuron in the thalamus then connects to the sensory cortex of the postcentral gyrus.

See also

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<span class="mw-page-title-main">Spinothalamic tract</span> Sensory pathway from the skin to the thalamus

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<span class="mw-page-title-main">Dorsal column–medial lemniscus pathway</span> Sensory spinal pathway

The dorsal column–medial lemniscus pathway (DCML) (also known as the posterior column-medial lemniscus pathway is the major sensory pathway of the central nervous system that conveys sensations of fine touch, vibration, two-point discrimination, and proprioception from the skin and joints. It transmits this information to the somatosensory cortex of the postcentral gyrus in the parietal lobe of the brain. The pathway receives information from sensory receptors throughout the body, and carries this in the gracile fasciculus and the cuneate fasciculus, tracts that make up the white matter dorsal columns of the spinal cord. At the level of the medulla oblongata, the fibers of the tracts decussate and are continued in the medial lemniscus, on to the thalamus and relayed from there through the internal capsule and transmitted to the somatosensory cortex. The name dorsal-column medial lemniscus comes from the two structures that carry the sensory information: the dorsal columns of the spinal cord, and the medial lemniscus in the brainstem.

<span class="mw-page-title-main">Medial lemniscus</span> Ascending bundle of axons which cross in the brainstem

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<span class="mw-page-title-main">Internal arcuate fibers</span> Axons of neurons that compose the brains gracile and cuneate nuclei

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<span class="mw-page-title-main">Dorsal column nuclei</span> Nuclei in the dorsal column of the brainstem

The dorsal column nuclei are a pair of nuclei in the dorsal columns of the dorsal column–medial lemniscus pathway (DCML) in the brainstem. The name refers collectively to the cuneate nucleus and gracile nucleus, which are situated at the lower end of the medulla oblongata. Both nuclei contain second-order neurons of the DCML, which convey fine touch and proprioceptive information from the body to the brain via the thalamus.

<span class="mw-page-title-main">Posterolateral tract</span>

The posterolateral tract 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 most developed in the upper cervical regions.

<span class="mw-page-title-main">Ventral posterior nucleus</span>

The ventral posterior nucleus is the somatosensory relay nucleus in thalamus of the brain.

<span class="mw-page-title-main">Principal sensory nucleus of trigeminal nerve</span>

The principal sensory nucleus of trigeminal nerve is a group of second-order neurons which have cell bodies in the caudal pons.

<span class="mw-page-title-main">Ventral posteromedial nucleus</span> Nucleus of the thalamus

The ventral posteromedial nucleus (VPM) is a nucleus of the thalamus and serves an analogous somatosensory relay role for the ascending trigeminothalamic tracts as its lateral neighbour the ventral posterolateral nucleus serves for dorsal column–medial lemniscus pathway 2nd-order neurons.

The spinoreticular tract is a partially decussating (crossed-over) four-neuron sensory pathway of the central nervous system. The tract transmits slow nociceptive/pain information from the spinal cord to reticular formation which in turn relays the information to the thalamus via reticulothalamic fibers as well as to other parts of the brain. Most (85%) second-order axons arising from sensory C first-order fibers ascend in the spinoreticular tract - it is consequently responsible for transmitting "slow", dull, poorly-localised pain. By projecting to the reticular activating system (RAS), the tract also mediates arousal/alertness in response to noxious (harmful) stimuli. The tract is phylogenetically older than the spinothalamic ("neospinothalamic") tract.

<span class="mw-page-title-main">Trigeminal lemniscus</span> Nerve tract

The trigeminal lemniscus or the trigeminothalamic tracts is a somatosensory tract containing second-order neuron fibers of the trigeminal system. It consists of the ventral and dorsal trigeminal tracts. Its second-order sensory axons convey tactile, pain, and temperature impulses from the skin of the face, the mucous membranes of the nasal and oral cavities, and the eye, as well as proprioceptive information from the facial and masticatory muscles.

The dorsal trigeminal tract are uncrossed second-order sensory fibers conveying fine (discriminative) touch and pressure information from the dorsomedial division of principal sensory nucleus of trigeminal nerve to the ipsilateral ventral posteromedial nucleus of thalamus. Second-order fibers from the ventrolateral division of the principal sensory nucleus meanwhile cross-over to ascend contralaterally in the ventral trigeminal tract along with those fibers arising from the spinal trigeminal nucleus.

<span class="mw-page-title-main">Spinal cord</span> Part of the vertebral column in animals

The spinal cord is a long, thin, tubular structure made up of nervous tissue that extends from the medulla oblongata in the lower brainstem to the lumbar region of the vertebral column (backbone) of vertebrate animals. The center of the spinal cord is hollow and contains a structure called the central canal, which contains cerebrospinal fluid. The spinal cord is also covered by meninges and enclosed by the neural arches. Together, the brain and spinal cord make up the central nervous system.

References

  1. Purves, Dale (2012). Neuroscience (5th ed.). Sinauer Associates. p. 200. ISBN   9780878936953.
  2. Anthoney, T. R. (1993). Neuroanatomy and the neurologic exam: a thesaurus of synonyms, similar-sounding non-synonyms, and terms of variable meaning. CRC Press.

Sources