Ner 20: Thalamus And Somatosensory System: Cranial Nerves

Front 1

4 cranial nerves with sensory components

Back 1

5, 7, 9, 10

Front 2

Information conveyed by oral vs interpolar vs caudal parts of the spinal trigeminal nucleus

Back 2

Oral and interpolar - reflexes related to blinking, lacrimination, salivation ect.
Caudal - pain and temp

Front 3

Pain/Temp path for head

Back 3

1) Sensory fibers have cell bodys in trigeminal ganglion. Enter at mid pons, have some ascending fibers for reflexes, most descend via spinal trigeminal tract (intermingles with tract of lissauer.
2) Neurons synapse on nuclei in spinal trigeminal nucleus (cadaul part) and reticular formation just medial, at level of caudal medulla.
3) Seconday neurons decussate and ascend via trigeminothalamic tract.
4) Axons synapse on VPM nuc of thalamus. These axons pass through post limb of internal capsule to ventral part of postcentral gyrus.

Front 4

Tactile pathway for the head

Back 4

1) Sensory nerve nuclei are in trigeminal ganglion. Axons enter at mid pontine level and synapse on principle trigeminal nucleus.
2) Axons from nucleus decussate and ascend via the trigeminothalamic tract.
3) Axons synapse on VPM nucleus. Axons travel via post limb of internal capsule to face region of postcentral gyrus.