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Anterior Trigeminothalamic Tract
The ventral trigeminal tract, ventral trigeminothalamic tract, anterior trigeminal tract, or anterior trigeminothalamic tract, is a nerve tract, tract composed of second-order neuron, 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 sensory nucleus of trigeminal nerve, principal, or main sensory nucleus and the spinal trigeminal nucleus, to the ventral posteromedial nucleus of the thalamus. The ventral trigeminal tract is also called the anterior trigeminal lemniscus. Structure The first-order neurons from the trigeminal ganglion enter the pons and synapse in the Principal sensory nucleus of trigeminal nerve, principal (chief sensory) nucleus or spinal trigeminal nucleus. Axons of the second-order neurons cross the m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sensory System
The sensory nervous system is a part of the nervous system responsible for processing sensory information. A sensory system consists of sensory neurons (including the sensory receptor cells), neural pathways, and parts of the brain involved in sensory perception and interoception. Commonly recognized sensory systems are those for vision, hearing, touch, taste, smell, balance and visceral sensation. Sense organs are transducers that convert data from the outer physical world to the realm of the mind where people interpret the information, creating their perception of the world around them. The receptive field is the area of the body or environment to which a receptor organ and receptor cells respond. For instance, the part of the world an eye can see, is its receptive field; the light that each rod or cone can see, is its receptive field. Receptive fields have been identified for the visual system, auditory system and somatosensory system. Senses and receptors Whi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trigeminal Lemniscus
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. It terminates by synapsing with third-order neurons in the ventral posteromedial nucleus of the thalamus. This tract was historically considered a cephalic division of the medial lemniscus due to the close proximity of the two ascending tracts. Like the medial lemniscus in the dorsal column-medial lemniscus pathway (DCML), that carries mechanosensory information from part of the head and the rest of the body, the trigeminal lemniscus carries mechanosensory information from the face. However, the trigeminal lemniscus also carries p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dorsal Trigeminal Tract
The dorsal trigeminal tract (also dorsal trigeminothalamic tract, or posterior trigeminothalamic tract) are un crossed 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. The DTT may be likened functionally to the medial lemniscus. Trigeminal ganglion → first-order neurons → dorsomedial division of principal sensory nucleus of trigeminal nerve (in pons) (synapse) → second-order neurons → trigeminal lemniscus (in midbrain) → (ipsilateral) ventral posteromedial nucleus of the thalamus (synapse) → third-order neurons → sensory cortex of postcentral gyrus In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Postcentral Gyrus
In neuroanatomy, the postcentral gyrus is a prominent gyrus in the lateral parietal lobe of the human brain. It is the location of the primary somatosensory cortex, the main sensory receptive area for the sense of touch. Like other sensory areas, there is a map of sensory space in this location, called the '' sensory homunculus''. The primary somatosensory cortex was initially defined from surface stimulation studies of Wilder Penfield, and parallel surface potential studies of Bard, Woolsey, and Marshall. Although initially defined to be roughly the same as Brodmann areas 3, 1, and 2, more recent work by Kaas has suggested that for homogeny with other sensory fields only area 3 should be referred to as "primary somatosensory cortex", as it receives the bulk of the thalamocortical projections from the sensory input fields. Structure The lateral postcentral gyrus is bounded by: * medial longitudinal fissure medially (to the middle) * central sulcus rostrally (in front) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sensory Cortex
The sensory cortex can refer sometimes to the primary somatosensory cortex, or it can be used as a term for the primary and secondary cortices of the different senses (two cortices each, on left and right hemisphere): the visual cortex on the occipital lobes, the auditory cortex on the temporal lobes, the primary olfactory cortex on the uncus of the piriform region of the temporal lobes, the gustatory cortex on the insular lobe (also referred to as the insular cortex), and the primary somatosensory cortex on the anterior parietal lobes. Just posterior to the primary somatosensory cortex lies the somatosensory association cortex or area, which integrates sensory information from the primary somatosensory cortex (temperature, pressure, etc.) to construct an understanding of the object being felt. Inferior to the frontal lobes are found the olfactory bulbs, which receive sensory input from the olfactory nerves and route those signals throughout the brain. Not all olfactory infor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ventral Posterolateral Nucleus
The ventral posterolateral nucleus (VPL) is one of the subdivisions of the ventral posterior nucleus in the ventral nuclear group of the thalamus. It relays sensory information from the second-order neurons of the neospinothalamic tract and medial lemniscus (of the dorsal column-medial lemniscus pathway) which synapse with the third-order neurons in the nucleus. These then project to the primary somatosensory cortex in the postcentral gyrus. There is uncertainty regarding the location of VMpo (posterior part of ventral medial nucleus), as determined by spinothalamic tract (STT) terminations and staining for calcium-binding proteins, and several authorities do not consider its existence as being proved. The term "ventral posterolateral nucleus" was introduced by Le Gros Clark in 1930. Anatomy Subdivisions The oral part of the ventral posterolateral nucleus (nucleus ventrointermedius) in the human, (VPLO) is a subdivision of the VPL with projections to the motor cortex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trigeminal Ganglion
The trigeminal ganglion (also known as: Gasserian ganglion, semilunar ganglion, or Gasser's ganglion) is the sensory ganglion of each trigeminal nerve (CN V). The trigeminal ganglion is located within the trigeminal cave (Meckel's cave), a cavity formed by dura mater. Anatomy The trigeminal ganglion contains cell bodies of the pseudo-unipolar sensory neurons of the trigeminal nerve which extend their axons both distally/peripherally into the three divisions of the trigeminal nerve on the one end, and proximally/centrally to the brainstem on the other end; the trigeminal root extends from the trigeminal ganglion to the ventrolateral aspect of the pons. The trigeminal ganglion is situated within the trigeminal cave (or Meckel's cave), a cerebrospinal fluid-filled cavity formed by a double layer of dura mater overlying the trigeminal impression near the apex of the petrous part of the temporal bone. Structure The trigeminal ganglion is somewhat crescent-shaped, with its co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
First-order Neuron
In mathematics and other formal sciences, first-order or first order most often means either: * "linear" (a polynomial of degree at most one), as in first-order approximation and other calculus uses, where it is contrasted with "polynomials of higher degree", or * "without self-reference", as in first-order logic and other logic uses, where it is contrasted with "allowing some self-reference" (higher-order logic) In detail, it may refer to: Mathematics * First-order approximation * First-order arithmetic * First-order condition * First-order hold, a mathematical model of the practical reconstruction of sampled signals * First-order inclusion probability * First Order Inductive Learner, a rule-based learning algorithm * First-order reduction, a very weak type of reduction between two computational problems * First-order resolution * First-order stochastic dominance * First order stream Differential equations * Exact first-order ordinary differential equation * First-o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thalamus
The thalamus (: thalami; from Greek language, Greek Wikt:θάλαμος, θάλαμος, "chamber") is a large mass of gray matter on the lateral wall of the third ventricle forming the wikt:dorsal, dorsal part of the diencephalon (a division of the forebrain). Nerve fibers project out of the thalamus to the cerebral cortex in all directions, known as the thalamocortical radiations, allowing hub (network science), hub-like exchanges of information. It has several functions, such as the relaying of sensory neuron, sensory and motor neuron, motor signals to the cerebral cortex and the regulation of consciousness, sleep, and alertness. Anatomically, the thalami are paramedian symmetrical structures (left and right), within the vertebrate brain, situated between the cerebral cortex and the midbrain. It forms during embryonic development as the main product of the diencephalon, as first recognized by the Swiss embryologist and anatomist Wilhelm His Sr. in 1893. Anatomy The thalami ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Principal Sensory Nucleus Of Trigeminal Nerve
The principal sensory nucleus of trigeminal nerve (or chief sensory nucleus of V, main trigeminal sensory nucleus) is a group of second-order neurons which have cell bodies in the caudal pons. It receives information about discriminative sensation and light touch of the face as well as conscious proprioception of the jaw via first order neurons of CN V. * Most of the sensory information crosses the midline and travels to the contralateral ventral posteromedial nucleus (VPM) of the thalamus via the anterior trigeminothalamic tract The ventral trigeminal tract, ventral trigeminothalamic tract, anterior trigeminal tract, or anterior trigeminothalamic tract, is a nerve tract, tract composed of second-order neuron, second-order neuronal axons. These afferent fibers carry sensor .... * However, information of the ''oral cavity'' travels to the ipsilateral VPM of the thalamus via the dorsal trigeminothalamic tract. {{Authority control Cranial nerve nuclei Trigeminal nerve Pon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ventral Posteromedial Nucleus
The ventral posteromedial nucleus (VPM) is a nucleus within the ventral posterior 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 term "ventral posteromedial nucleus" was introduced by Le Gros Clark in 1930. Afferents and efferents Orofacial somatosensory The VPM receives second-order general somatic afferent fibers from the ventral trigeminal tract and the dorsal trigeminal tract which convey general somatic sensory information from the face and oral cavity (including touch, pressure, temperature, pain, and propriception). Proprioceptive synapses are situated anteriorly, ones mediating touch in the middle, and nociceptive ones posteriorly. Third-order neurons in turn project to the somatosensory cortex in the postcentral gyrus. Taste The VPM receives second-order tas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Afferent Fiber
Afferent nerve fibers are axons (nerve fibers) of sensory neurons that carry sensory information from sensory receptors to the central nervous system. Many afferent projections ''arrive'' at a particular brain region. In the peripheral nervous system, afferent nerve fibers are part of the sensory nervous system and arise from outside of the central nervous system. Sensory and mixed nerves contain afferent fibers. Structure Afferent neurons are pseudounipolar neurons that have a single process leaving the cell body dividing into two branches: the long one towards the sensory organ, and the short one toward the central nervous system (e.g. spinal cord). These cells do have sensory afferent dendrites, similar to those typically inherent in neurons. They have a smooth and rounded cell body located in the ganglia of the peripheral nervous system. Just outside the spinal cord, thousands of afferent neuronal cell bodies are aggregated in a swelling in the dorsal root known as the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
