Midbrain HY

Question 1

locus ceruleus - location, function?

Answer 1

• rostral pons at midbrain junction
• medial
• stains dark in fresh tissue (neuromelanin)
• supplies entire CNS with noradrenergics (NE) –> attention, vigilance
• inc discharge during arousal, dec during sleep

Question 2

trochlear nucleus - location, function?

Answer 2

• caudal midbrain
• medial
• only nerve that exits dorsally

-innervates superior oblique (somatic motor)

Lesion:

• no dramatic loss
• may have trouble descending stairs
• may have slight diplopia while reading

Question 3

occulomotor nucleus - location, function?

Answer 3

• rostral midbrain
• medial

-innervates levator palpebrae superioris, inf./sup./medial rectus, inf oblique (somatic motor)

Lesion:

• lateral gaze (MLF)
• ptosis

Question 4

Edinger-Westphal Nucleus

Answer 4

• rostral midbrain
• medial
• parasympathetic preganglionic cells
• innervates sphincter pupillae, ciliary muscle (visceral motor)

Lesion:
-dilated pupil, unresponsive to light

Question 5

nigra striata

Answer 5

• contains dopamine neurons

- lose 80% = Parkinson’s Disease