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| Laboratory 12 : Tract Systems I |
| Somatosensory System : Dorsal Column Medial Lemniscal Tract |
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Dorsal Column Medial Lemniscal Tract
It is important to note that:
- This tract carries somatosensory info from entire spinal cord: limbs and trunk .
- Decussation occurs in caudal medulla after synapsing on nucleus gracilis and nucleus cuneatus.
- This tract transmits info about touch, pressure, vibrations, joint position, muscles, and tendons.
- It does NOT transmit info about pain or temperature (like Neospinalthalmic Tract does)
- Since it’s a specific tract, it is somatotopic and submodality specific.
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Slide 90 : Telencephalon
- Synapses in 1º somatosensory cortex in cerebrum.
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Slide 67 : Diencephalon
- Synapses with VPL (lateral projection nuclei) in thalamus.
- Transmits through internal capsule to cerebrum.
- Procedes towards 1º somatosensory cortex.
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Slide 45 : Pons/Midbrain
- Passes through medial leminiscus.
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Slide 26 : Medulla
- Continues through medial leminiscus.
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Slide 18 : Caudal Medulla
- Tract from upper half of body enters fasciculus cuneatus, then nucleus cuneatus.
- Lower half enters fasciculus gracilis, then nucleus gracilis.
- Sensory collaterals synapse on neurons of either nucleus cuneatus or nucleus gracilis.
- Cuneate or gracile axons (internal arcuate fibers) decussate, entering medial leminiscus.
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Slide 8: C1
- Sensory neurons enter from upper half of the body into dorsal root, and collaterals pass through dorsal funiculus.
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Slide 2 : L6
- Sensory neurons enter from lower half of the body into dorsal root and collaterals pass through dorsal funiculus.
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Copyright © 2006 - University of Pennsylvania School of Veterinary Medicine, All rights reserved.
Faculty: Dr. Richard Miselis, Dr. Peter Hand
Students: Natalie Fickel V'12, Ryan Donahue V'09, Cara Catanese V’08, Rebecca Wolf V'06, Keith Javic V'03, Ken Bixel V'99, Russel Howe-Smith V'97
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