Section 7, Part ? Flashcards
What is the tectum?
The tissue positioned above the aqueduct
What makes up the tectum?
Superior colliculi and inferior colliculi
How many colliculi are there?
4….2 inferior and 2 superior
Where is the midbrain tegmentum located…ventrally or dorsally?
Ventrally
What does the midbrain merge with rostrally?
Thalamus
What marks the boundary between the midbrain and diencephalon?
Posterior Commissure (dorsally)
What is the function of the posterior commissure?
Form a bridge between the Pretectal area (nuclei) of each side of the brainstem
What overlays the posterior commissure?
Pineal body
What pathology will press down no the posterior commissure? What are the diagnostic symptoms?
Pinealoma
First diagnositc symptom of a pinealoma is a paralysis of upward eye movements.
As the tumor grows, there is loss of pupilary light reflex (fixed, dilated pupils result), and possible hydrocephalus because obstruction of cerebral aqueduct
What is the interstitial nucleus of Cajal involved in?
it is the vertical gaze center. So pathology presents as inability to look up and down
Where is Cajal located?
Within the reticular formation at the rostral end of the MLF in the midbrain
What terminates at the inferior colliculus?
lateral lemniscus
Where dies the inferior colliculus send axons?
To the thalamus
How does the inferior colliculus send axons to its target?
brachium of the inferior colliculus
Where does the brachium of the inferior colliculus end?
It ends in the MGN (Medial geniculate nucleus)
What type of information does the inferior colliculus transmit?
It relays auditory information from both ears to auditory cortex (Heschl’s gyrus, transverse temporal gyrus, and auditory cortex)
Where is the medial lemniscus located?
Just ventral to the lateral lemnisus in the caudal part of the midbrain
What does the medial lemniscus carry?
Epicritic sensory signals for the contralateral side of the body
In the midbrain, where are anterolateral tracts found?
Lie between the LL and ML
If there is a lesion involving the dprsal tegmentum in the lateral midbrain, what would the symptoms be?
protopathic and epicritic sensory loss from the opposite side of the body and face
Which cerebellar peduncle deccussates at the level of the midbrain?
Superior cerebellar peduncle
After the fibers of the Superior cerebellar peduncle cross, where do some end up?
Red Nucleus
LA and VL nucleus of the thalamus
What does the red nucleus give rise to?
Brainstem- spinal motor pathway…the Rubrospinal tract
There are also some projections to the Inferior olivary complex
Some to the LA and VL nucleus of the thalamus
Is the trochlear nucleus caudal or rostral in the midbrain?
Caudal
Is the oculomotor mucleus located caudal or rostral in the midbrain?
rostral
What is dorsal to the CN IV and CN III nuclei (in the tegmentum) of the midbrain?
periaqueductal gray
