18 - Motor control and the corticobulbar tract Flashcards
Why isn’t there requirement for an extrapyramidal pathway in the CBT?
- vestibular apparatus in the ear provides feedback to the tract
- gamma neurones are not required as cranial nerves typically only supply the head and neck region
Where does the UMN in the CBT originate from?
Lateral surface of PMC
Where does the UMN exit the internal capsule?
Genu
What is the name for an UMN in the CBT?
Supranuclear fibre
What is the name for a LMN in the CBT?
Cranial nerve
Describe how UMN typically synapse with the cranial nerve nuclei.
Bilaterally
Describe how the CN typically emerge from the nuclei.
Ispilaterally
What is the exception when the UMN synapses with the cranial nerve nuclei?
- lower nuclei of the facial nerve (CN VII)
- hypoglossal nerve (CN XII)
Which nerve is the only to emerge posterior from its nuclei?
Trochlear (CN IV)
Which nerve is the only to emerge contralaterally from its nuclei?
Trochlear (CN IV)
Which nuclei are located in the midbrian?
- oculomotor (CN III)
- trochlear (CN IV)
Which nuclei are located in the pons?
- trigeminal (CN V)
Junction to medulla : - abducens (CN VI)
- facial (CN VII)
- vestibulocochlear (CN VIII)
Which nuclei are located in the medulla?
- nucleus ambiguus
- accessory (CN XI)
- hypoglossal (CN XII)
What is the nucleus ambiguus?
- glossopharyngeal (CN IX)
- vagus (CN X)
- accessory (CN XI)
Describe the oculomotor nucleus.
- bilateral innervation
- CN emerge ipsilaterally
