Functional Anatomy of the Brainstem
Name the 3 main parts of the brainstem
Midbrain, pons, medulla oblongata
Brainstem death is the irreversible loss of what two capacities?
Consciousness + the capacity to breathe
First step: Before doing any brainstem death tests, what must doctors first be sure about overall?
There is an irreversible loss of brain function (and they must identify the cause).
Which scan builds a brain image using differential absorption of X-rays?
CT scan
What does randomised mean in an RCT?
Participants are randomly allocated to treatment vs comparison groups
The midbrain has two main parts:Name one
Tectum OR cerebral peduncles
the brainstem controls basic body functions like what key function? name 3
breathing/ heart rate/ blood pressure and digestion
Give one cause that can lead to irreversible brain function loss.
Severe head injury / hypertensive intracerebral haemorrhage / hypoxic-ischaemic insult.
CT shows “gross features” but has what limitation?
Very low resolution
What does controlled mean in an RCT
It uses a comparison/control group so confounders are better controlled and groups are made similar.
Which midbrain structure contains the superior and inferior colliculi?
Tectum
Which brainstem system helps maintain consciousness/arousal?
Reticular system (reticular formation/RAS) of the pons
Before testing, doctors must rule out “things that can make someone look brain-dead but aren’t.” Name two
Shock/hypotension / hypothermia <32°C / certain drugs / brainstem encephalitis / GBS / encephalopathy / severe hypophosphatemia
Which method measures electrical activity using electrodes on the scalp?
EEG
What is a Type I error?
A false positive (incorrectly rejecting the null).
The pons contains ascending tracts such as spinothalamic and which dorsal column pathway ( double points if you can also name where this pathway relays information to
medial lemniscus --> thalamus --> Primary somatosensory cortex
“Can’t breathe or cough” is linked to which cranial nerve
CN X (Vagus)
What bedside test uses cold water in the ear to check the brainstem pathway that normally makes the eyes move?
Caloric test / oculo-vestibular reflex test
Which scan measures brain activity by tracking blood oxygenation/blood flow changes?
fMRI
What is Type II error?
A false negative (failing to reject the null when there is an effect).
Name two key external feature on the anterior medulla
Pyramids OR olives OR Ventrolateral and posterolateral sulci
''No pupillary reflex'' is linked to which two cranial nerves
CN II and CN III
What test checks whether the patient can breathe on their own when the ventilator is briefly stopped (to test brainstem drive)?
Apnoea test.
Which technique maps functional processes using short-lived radioactive tracers attracted to glucose?
PET scan
list factors that affect power—name 3
sample size, effect size, variance, significance level.