Lecture 13 Flashcards
1
Q
Who was Phineas Gage?
A
- Damage to frontal brain and VM prefrontal cortex
- Had frontal lobe syndrome
- Impairments in personal and social decision making with preserved intellectual abilities decisions often lead to losses in finance or social status or conflict with family and friends
- Choices different from pre-morbid period problem-solving in the lab is normal
- Had deficits in feeling/expression of emotions that is NOT explainable in terms of memory, intellect, language ability or attention
2
Q
What is the IOWA gambling task?
A
- Investigates Ventral Medial prefrontal cortex syndrome
- Task is based in rounds and mimics repeated decisions we need to take via A,B,C,D
- Creates conflict between immediate reward and a delayed probabilistic punishment
- Risky choices with no clear prediction of outcomes
- Benefits from hunches or gut feelings
3
Q
What are somatic markers?
A
- Activation of somatic states that attach values to certain options or scenarios
- Overall neural system involved is larger than just VM prefrontal cortex
- Central role of somatic states as signal functional in decision making
4
Q
What is evidence that emotions guide decisions?
A
- Emotions provide go, stop, turn signals in light of alternative scenarios = provide quick decisions
- If lacking, decisions become dependent on cumbersome, slow reasoning
- IGT: four card decks = to maximise profit on a loan of play money
- Ppts make a series of 100 card selections: A&B generate 100£ each time they win but there is higher unpredictable punishment whereas C&D win 50
- VMPFC patients do not avoid the bad decks
5
Q
Is impairment linked to failure in somatic signalling?
A
- Looked at SCR in VM patients
- All decks show the same level of SCR response - little to none
- In control groups: A&B show greatest SCR
6
Q
Do emotional signals need to be conscious? (Results of IGT)
A
- Ppts go through phases: 1 pre-punishment, 2 pre-hunch, 3 hunch, 4 conceptual
- Behaviour: normal patients have a preference for A/B during pre-punishment, hint of shift away from A/B in 2, definite shift in 3/4
- VM patients show a preference for A/B with no shift ever occurring
- SCR: normal patients show no SCR in 1, but substantial SCR in 2/3/4, VM patients had no SCR ever occurring
- Self-report = normal patients have no clue in 1/2, but 70% figure out distinction between A/B/C/D in 3/4
- VM: only 50% understanding in intervals corresponding to 3/4
- People will be aware of the reward schedule perhaps, but will not decide to act that way
- Knowledge without somatic signalling leads to dissociation between what one knows and how one decides to act
- Other examples are drug addiction/psychopathy
7
Q
What is the amygdala?
A
- Almond shaped structure, part of brain stem, part of limbic system
- Ancient part of brain involved with emotions
- Amygdala couples object features with its emotional attributes e.g monkeys afraid of snakes, when they have amygdala removed = show no fear toward snakes
- Amygdala patients have the same results with IGT: select more cards from A/B, also do not show any SCR before selection of card OR when told they had lost money
- Output of amygdala is not reaching to the Vm and they cannot process it the right way = shows different parts of brain working together
8
Q
What are the somatosensory and insular cortices?
A
- Anosognosia - damage to right hemisphere
- Patients cannot move left side of body but are not aware of problem
- Unable to make appropriate decisions on personal/social matters
- Somatosensory structures in brain are critical for decision making as they hold representations of somatic states
- Ventral medial frontal lobe is where everything is put together
- The insula cortex is between temporal and frontal lobe: to do with body posture and feedback - deeply folded
- Somatosensory cortex has a representation of body parts
9
Q
What are primary vs secondary inducers?
A
- VMPFC connects memories of events (secondary inducers) with somatic state representations of that memory
- Patients with VM frontal lesions have difficulties re-experiencing remembered emotional episodes, or life events
- Normal development of VM system depends on integrity of the amygdala
10
Q
What are the affective input of somatic markers?
A
- Somatic states can be integral to the decision task at hand e.g should I speed when I am late for an interview = emotional state may stem from embodied representation of fear to get into accident
- Somatic state can be unrelated to the decision task at hand = emotional state may stem from an embodied response
- Research approach: induction of strong emotional states like when you recall life events reduces the number of advantageous choices in a subsequent IGT = when affect is in foreground = can affect decision making for the worse
11
Q
What was a study looking at somatic markers and their influence on decision making?
A
- Where the affective input is absent
- Looking at amygdala and insula patients compared to controls
- 20 rounds of playing with starting money of $20, and you must choose to invest in each round. If you do not invest, you go to the next round
- If you invest = 50% chance of losing $1, 50% chance of winning $2.50
- Target patients invested in 83% of rounds whereas normals invested in 57%
- In normal people, the loss aversion takes over as you react emotionally to outcomes of rounds
- Depends on how the expected values are arranged to see if it is beneficial to see if there is no affective input
12
Q
What is some games looking at social decision making?
A
- Trust game: player decide how much of an endowment to invest with a partner. Money multiplies and trustee has choice to return/not to. If money is returned, both parties payoff is higher than original endowment, if not = investor has loss
- Ultimatum game: 2 players divide sum of money, proposer specifies a division, responder may accept/reject = if reject = both receive nothing
- Dictator game: same as ultimatum but second player has no choice and must accept
13
Q
What are the lesions in social decision making? (Games)
A
- Lesions in in VMPFC, and they overlapped between 6 patients
- Trust game: lesioned patients exhibited less trust and were less trustworthy
- Ultimatum: no difference between offers/demands
- Dictator: VMPFC gave less than controls
