Somatosensory

Question 1

Fasiculus Gracilis?

Answer 1

medial dorsal column (thin), with lower body fibers

Question 2

Fasiculus cuneatus?

Answer 2

Wedge shaped, lateral upper body fibers

Question 3

Position of medial lemniscus with sensory fibers in:

1. medulla
2. pons/midbrain

Answer 3

1. In medulla, little person is standing up

2. In pons and midbrain, person lies down with legs lateral (typical positioning)

Question 4

Where in the thalamus do somatosensory fibers synapse?

Where do they travel in the internal capsule?

Answer 4

VPL: ventral posterior lateral nucleus

Travel in posterior limb of internal capsule in thalamic somatosensory radiations

Question 5

Where do somatosensory fibers for face synapse and what is this pathway called?

Answer 5

VPM: ventral posterior medial nucleus of thalamus

Trigeminal lemniscus

Question 6

Lateral cord lesions affecting contralateral pain/temp begin where relative to lesion?

Answer 6

2-3 segments BELOW the level of the lesion. So starting at where the sensory level is, the lesion is above.

Question 7

Which sensory neurons are myelinated: thick large posterior column neurons or thin, small fiber anterolateral neurons?

Answer 7

posterior column axons are myelinated

Question 8

Name of tract for modulation of pain? What are the areas involved (2)?

Answer 8

spinomesencephalic tract: projects to periaqueductal grey and superior colliculi

Question 9

5HT neurons from where for central pain?

Answer 9

Raphe nuclei at rostral ventral medulla / pontomedullary junction to spinal cord dorsal horn

Question 10

Which thalamic nuclei does NOT project to the cortex?

Answer 10

Thalamic reticular nucleus: inhibitory GABAergic neurons, regulate thalamic activity

Question 11

Thalamic nuclei for somatosensory (2)

Answer 11

VPL, VPM (ventral posterior lateral (body) and medial (face)

Question 12

Thalamic nuclei for vision

Answer 12

LGN: lateral geniculate

Question 13

Thalamic nuclei for auditory

Answer 13

MGN: medial geniculate nucleus

Question 14

Thalamic nuclei for motor paths from cerebellum and basal ganglia?

Answer 14

VL: Ventral lateral

Question 15

Colliculi for vision?

Answer 15

Superior colliculi

Question 16

Colliculi for hearing?

Answer 16

inferior colliculus

Question 17

thalamic nuclei for limbic paths to anterior cingulate cortex?

Answer 17

Anterior nuclear group

Question 18

thalamic nuclei involved in association / orientation of visual and other stimuli?

Answer 18

Pulvinar

Question 19

Thalamic nuclei involved in frontal association cortex functions

Answer 19

MD medial dorsal

Question 20

Dejerine-Roussy syndrome?

Answer 20

Thalamic lesion: severe contralateral pain

Question 21

localize: loss of pain and temp on body opposite lesion but face on same side of lesion. Especially of lips, fingertips, distal > proximal

Answer 21

Lateral pons or lateral medulla: anterolateral pathways and spinal trigeminal nucleus on same side

Question 22

Localize: hemibody sensory loss sparing pinprick/temp and sparing face

Answer 22

Medial medulla: involves medial lemniscus causing contralat loss of JP/vibration

Question 23

Pick spinal cord level for:

1. Tricep
2. Grip, finger extension
3. Bowel/bladder

Answer 23

1. C7
2. C8-T1
3. S2-S4