Brainstem Centers that influence Motor Activity - Corticobulbar Tract Flashcards
Where is the cortico-bulbar tract ?
From the cortex to the brainstem
What is the function of the cortico-bulbar tract ?
To control muscles of the face, head and neck
How many neurons are in the cortico-bulbar tract ?
One neuron: an UMN that projects to LMN in cranial nerve motor nuclei in the brainstem
Which tract gives you voluntary control over cranial nerve nuclei
The cortico-bulbar tract
Route of the cortico-bulbar tract ?
Precentral/motor nuclei -> Corona radiata –> Internal capsule -> (They travel close to the CST but the CBT is more anterior and closer to the genu) CN nuclei in the brainstem
What is the relationship of the CST and CBT in the crus cerbri ?
The CST is in the center of the crus cerbri but the CBT is more medial
Which cranial nerve nuclei receive bilateral termination from the cortico-nuclear/cortico-bulbar tract ?
CN V, CN IX, CN X, and CN XI
Which CN nuclei receive contralateral innervation ?
CN VII and CN XII
How to distinguish Bells Palsies pts from stroke patients.
Bell’s Palsies patients will be unable to wrinkle forehead whether attempting to look up with eyes without moving face or whether attempting to forthright wrinkle forehead
Peripheral Cranial VII lesion
This is Bell’s Palsy so both ipsilateral as well as contralateral innervation will be lost from the forehead on the affected side. For this reason the patient will be unable to wrinkle the forehead on that side.
Where might a PCA stroke affect
It is midbrain, it hits the crus cerbri downstream so hits muscles of facial expression, but not necessarily everything. Sometimes just the pons.
If the hypoglossal lesion is lower motor
Patient will lick their injury
It the hypoglossal lesion is UMN
Tongue will deviate from lesion
Bulbar Palsy characteristics
Lesion of the LMN neurons in the brainstem. When these are lesioned this causes issues with face mainly, so mastication, facial, larynx, tongue. Muscles will atrophy so there will be fasiculations in the tongue.
What are causes of bulbar palsies
Infarcts like stroke, motor neuron disease, cancers, neck trauma, aneurysms, GB, MS, MG
