Lecture 21 (4/23)

Question 1

Corticobulbar tract

Answer 1

Originates in the lower ⅓ of the primary motor cortex and descends into the brainstem

Controls muscles of the head, neck, and face

Question 2

Corticospinal tract

Answer 2

Originates in the upper ⅔ of the primary motor cortex and descends into the spinal cord

Question 3

Which of these two tracts would you expect to be involved with issues of speech production?

Answer 3

Corticobulbar

because the corticobulbar tract provides all input to the cranial nerves

Hypoglossal - problems with articulation of consonants that require movement by the tongue to produce them (n,t,d)

Question 4

Upper Motor Neurons

Answer 4

Bilateral lesion causes paralysis in both sides

UMN damage manifests differently than LMNs

• Use homunculus to know where damage has occurred
• If damage is near/on a CN it may tell us where it is