Week 8.2 Flashcards
How can we test a patient’s ventral stream?
- ask them to draw a line in the plane of a given object
- can’t if there is ventral stream damage
- ask them to put a card in a slot, can because that requires an unconscious knowledge of the relationship between the objects
What is prosopagnosia?
the inability to recognize faces, but a retained emotional response to familiar faces
What is capgras syndrome?
the ability to recognizes faces as familiar but without any emotional response, leading one to the belief their loved one has been replaced
Which perceptual stream is damaged in those with prosopagnosia?
the ventral stream
Which cerebral hemisphere mediates confabulation?
the left
What are the four important structures for decision making?
- amygdala
- OFC
- DLPFC
- anterior cingulate cortex
What role does the amygdala play in decision making?
subconscious evaluation of meaning
When you walk into a room and “feel” something is wrong, which brain structure is responsible?
the amygdala
What role does the OFC play in decision making?
it is your intuition
How can we test the OFC?
with the gambling task
OFC lesions will cause what behavioral change?
loss of quick, intuitive judgements
What role does the DLPFC play in decision making?
it directs working memory and is the “decider”
Damage to the DLPFC will cause what behavioral change?
the individual will become very impulsive
What is the role of the anterior cingulate cortex in decision making?
it learns from error and decides whether behavior is successfully proceeding toward the desired goals
Which decision making center has very little input from sensory systems?
the DLPFC
Which systems of thinking, fast or slow, is capable of learning?
both are
Why is the fast system of thinking so quick?
it relies on hardwired rules of thumb
Which system of thinking, fast or slow, is more causal?
fast
The hyper-fast system of thinking is mediated by which brain structure?
the amygdala
What is the availability bias?
reliance on easily recalled (often emotionally charged) events to make decisions
What is another name for cognitive inertia?
the anchoring bias
When it comes to clinical practice, how should you utilize slow and fast thinking?
- rely on fast thinking when you’ve had lots of similar experience
- use slow thinking to reject simple solutions offered by the OFC then make a decision after a period of not thinking about it using “your gut” if the decision is complex
What is hypothetical-deductive reasoning?
the best diagnostic method
What are the steps of hypothetical-deductive reasoning?
- formulate a probabilistic differential
- continue to refine it by incorporating new data
- be comfortable with residual uncertainty
How is sensitivity calculated?
TP / (TP + FN)
How is specificity calculated?
TN / (TN + FP)
A highly specific test allows you to do what?
rule in disease with a positive test
A highly sensitive test allows you to do what?
rule out disease with a negative test
What is another name for post-test probability?
positive or negative predictive value
What is the equation for positive predictive value?
sensitivity(pre-test) + (1-specificity)(1-pretest)
What is the equation for negative predictive value?
(specificity) (1-pretest)
- ——————————————-
(specificity) (1-pretest) + (1-sensitivity)(pretest)
What is a coma?
pathologic absence of consciousness
What are the four levels of consciousness?
- alert
- lethargic
- stupor
- coma
If someone is in a coma, it means one of two things has been damaged?
- the RAS
- the cortex, diffusely
Describe the pathway between the RAS and the cortex
- RAS
- thalamic reticular nucleus
- cerebral cortex
What are the six types of coma?
- psychogenic
- diffuse cortical
- diencephalic
- supratentorial early
- supratentorial late
- subtentorial
Parasympathetic innervation of the eye induces what pupillary state?
constricted
Describe the state of someone’s pupils in the various types of coma.
- psychogenic: mid-range, reactive
- diffuse cortical: small, reactive
- diencephalic: small, reactive
- early supratentorial: small, reactive
- late supratentorial: mid-range, unreactive
- subtentorial: mid-range, unreative
What is the oculocephalic reflex?
“dolls eye reflex” which maintains a forward gaze when the head is turned (same as VOR)
How can we test a coma patient’s slow eye movements?
- oculocephalic reflex
- cold caloric
Normal response to cold calorics is what?
slow eye movement ipsilaterally
True or false, slow eye movements are sensitive to toxic-metabolic processes.
moderately true
Describe the eye movements for each type of coma.
- diffuse cortical: intact or abnormal
- diencephalic: intact
- early supratentorial: intact
- late supratentorial: abnormal
- subtentorial: abnormal
