Ascending Tracts Flashcards
List the ascending tracts
- fasciculus gracilis
- fasciculus cuneatus
- lateral spinothalamic
- anterior spinothalamic
- dorsal spinocerebellar
- ventral spinocerebellar
- spinotectal
- spinoreticular
- spino olivary
- spino vestibular
Describe the posterior column medial lemniscus pathway
1) peripheral sensory receptors
2) ganglion spinale
3) fasciculus gracilis or fasciculus cuneate
4) internal arcuate fibers (decussation)
5) medial lemniscus
6) primary somatosensory cortex (post central gyrus of parietal lobe)
Primary afferent fibers convey info ipsilaterally until the medulla where decussation takes place.
Posterior column is composed of fasciculus gracilis and cuneatus. Fasciculus gracilis enters the spinal cord through the ipsilateral dorsal spinal root, including sacral, lumbar and lower six thoracic nerves. The fasciculus cuneatus starts at the mid thoracic level from upper thoracic to cervical dorsal roots.
What is the function of the posterior column medial lemniscus pathway ?
Exteroception
List the spinocerebellar tracts
- dorsal spinocerebellar tract
- ventral spinocerebellar tract
- cuneocerebellar tract
What is the organization and function of the dorsal spinocerebellar tract ?
Function: to relay proprioception from ipsilateral trunk and lower limb to the anterior lobe to the cerebellum via the inferior peduncle. Level C8-L3. During active and passive movement.
What is the organization and function of the ventral spinocerebellar tract ?
It relays proprioceptive information from below L2-L3 to the anterior lobe of the cerebellum. Functionally ipsilateral even though it crosses the midline twice. During active movement.
What is the role of the cuneo cerebellar tract ?
Proprioceptive information from the neck, upper limb and upper half of the trunk. From C8 to C1.
What are the information conveyed by vestibular neurons?
Head position and velocity to the vestibular nuclei in the brain stem.
