Lecture 13: Brainstem and Cranial Nerves

Question 1

What is special about the relationship between olfactory stimuli and the limbic system, regarding the neuroanatomy?

Answer 1

Compared to other sensory systems, the olfactory pathway does not relay in the thalamus, but has a direct projection to the amygdala, via the lateral olfactory stria.

Question 2

Regarding the visual pathway, what is a likely diagnosis in cases of lesions to Meyer’s loop?

Answer 2

A contralateral superior quadrantanopia.

Question 3

Name the three cranial nerves involved in eye movements. Which muscles are innervated by theye nerves? Name autonomic functions involved in theye nerves.

Answer 3

Oculomotor nerve (III), trochlear nerve (IV) and the abducens nerve (V). CNIII is involved in the parasympathetic pupil constriction. CNIV innervates the superior oblique muscle, resulting in intorsion of the eye. CNV innervates the lateral rectus, resulting in eye abduction. CNIII innervates the remaining muscles for eye movement.

Question 4

Name the three subdivisions of the trigeminal nerve. Which parts of the face are related to the respective subdivisions?

Answer 4

The ophthalmic division (V1): the upper portion of the face, going down to the nose.
The maxillary division (V2): the middle portion of ghr face reaching from the cheeks to the upper lip.
The mandibular divisiom (V3): the lower part of the face reaching from the lower lip to the chin, including the jaw.

Question 5

Which cranial nerve is related to sensation (not taste!) of the anterior two thirds of the tongue? Which nerve is related to the remaining part?

Answer 5

The trigeminal nerve. The remaining part is related to the glossopharyngeal nerve.

Question 6

Name the motor, parasympathetic and visceral sensory functions of CNVII.

Answer 6

Motor: innervation of muscles for facial expression and other less important muscles.
Parasympathetic: lacrimal glands and salivary glands (except for parotid).
Visceral sensory: taste sensation of anterior two thirds of the tongue.

Question 7

Name the target of the taste sensation pathway, as well as the relevant nucleus in the brainstem.

Answer 7

The insula cortex. The rostral solitary nucleus.

Question 8

Describe the typical symptoms seen in lesions of CNVII. How do these symptoms differ from upper motor neuron lesions?

Answer 8

Lesions of the facial nerve typically lead to a complete contralateral paralysis of one side of the face. An upper motor neuron lesion will typically spare the forehead, due to bilateral cortical innervation.

Question 9

Name parasympathetic, visceral and motor functions of the glossopharyngeal nerve.

Answer 9

Innervation of the parotid gland (salivate), baroception and chemoception of carotid body, taste and somatic sensation of the posterior one third of the tongue and innervation of stylopharyngeus muscle (swallowing and talking).

Question 10

Name parasympathetic, visceral and motor functions of the vagus nerve.

Answer 10

Innervation of pharyngeal (swallowing and gag reflex) and laryngeal muscles (voice), innervation of heart, lungs and digestive system, taste sensation from epiglottis and pharynx and baro-/chemoception of aortic arch.

Question 11

Name the functions of CNXI.

Answer 11

Innervation of the sternomastoid and part of the trapezius muscle.

Question 12

Name the function of CNXII.

Answer 12

Innervation of tongue muscles except for palatoglossus.