Trigeminal System

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Trigeminal System
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Useful animations
https//www1.columbia.edu/sec/itc/hs/medical/neruo
anatomy/neuroanat/
Somatic sensory A007
Sensory cranial F003
Sensory cranial F004
Somatic sensory AN01
Somatic sensory A006
Readings Principles of NS General somatic
sensory organization 447-449 Brain stem/cranial
nerve review 873-880 Sensory nuclei 880-882,
Fig 44-6
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Nociceptors, thermoreceptors, itch receptors
are bare nerve endings
Mechanoreceptors are encapsulated
Bare nerve ending
Merkels receptor
Meissners corpuscle
Pacinian corpuscle
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Dorsal horn Anterolateral system spino-thal sp
ino-retic spino-mesen
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Components of the trigeminal system

• Spinal nucleus
• Caudal nucleus Pain/temp/itch
• Interpolar nucleus Pain/reflexes, etc, ???
• Oral nucleus Reflexes, etc, ???
• Main sensory nucleus Mechanosensation
• Mesencephalic nucleus Jaw proprioception
• Motor nucleus Jaw muscles

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Mesencephalic
Trigeminal motor
Main sensory
Spinal trigeminal nuc oral interpolar
caudal
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Organization of the spinal trigeminal nucleus
caudal nucleus
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Ophthalmic division
Maxillary division
Mandibular division
7, 9, 10
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C2
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1
C2
Interpolar nucleus
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Caudal nucleus
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1
C2
Upper spinal cord
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Input Small-diameter fibers Marginal zone
Substantia gelatinosa
Spinal trigeminal tract
Caudal nucleus
Output Marginal zone--gtThalamus,
midbrain Substantia gelatinosa--gtinterneurons
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Spinal trigeminal tract
Caudal nucleus
Anterolateral system
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Main sensory
Anterolateral/ trigeminothal
Trigeminal motor
Medial/trigeminal lemniscus
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Mesencephalic Nucleus tract
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Mesencephalic Nucleus tract
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Somatic Sensory Thalamus
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(No Transcript)
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(No Transcript)
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Anterolateral and Trigeminal Systems
Ventral posterior--gtPostcentral gyrus
localization
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Anterolateral System
Ventral medial post--gtInsular behavioral
autonomic responses Limbic
Amygdala
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Anterolateral and Trigeminal Systems
Medial dorsal--gtCingulate gyrus emotional
(-valence) Limbic
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Pain suppression path
Limbic cortex
Periaqueductalgray matter
Raphe nuclei(5-HT)
Caudal nucleus
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Trigeminal System

• Separate components for pain and touch
• Brain stem nuclei
• Caudal nucleus (pain)
• Interpolar nucleus (caudal part for pain-mouth)
• Oral nucleus (???)
• Main sensory nucleus
• 3 Separate thalamic pain nuclei 1 for touch
• Pain (VPM, VMpo, MD)
• Touch (VPM)
• 3 Separate cortical representations
• Postcentral gyrus (localization)
• Insular (important for pain)
• Cingulate (emotions, esp. for pain)
• Pain suppression system
• PAG--gtRaphe nuclei (5-HT)--gtCaudal nucleus