Task 7 Flashcards
7.1: Where can the amygdala be found in the brain?
- part of limbic system
- part of temporal cortex
- before/anterior to hippocampus
7.1: Why is the amygdala relevant for goal-directed decision making, and therefore for neuro-economic theory?
- encodes emotional information
- can influence decision making directly by influencing emotions
7.2: What are the two major misconceptions about amygdala function that obscure its contribution to
goal-directed decision making?
- Misconception: A is only involved in negative emotions
2. Misconception: A essential for reward learning
7.2: Why is the first misconception wrong (A involved only in negative emotions)?
-A also processes positive affect
7.2: What’s the evidence that the A also processes positive affect? –> monkey studies
- study: recorded from single neurons in A while visual stimuli acquired a positive or negative valence through Pavlovian conditioning –> amygdala activity reflected stimulus–valence pairings
- -> one population of neurons encoded positive valence and a largely separate group of cells encoded negative valence in A (no obvious spatial segregation; most were in the basolateral portion)
- Study: role of the amygdala is limited to updating the monkeys’ estimation of the current biological value of food
7.2: What’s the evidence that the A also processes positive affect? –> rat studies
-Study of Pavlovian approach behaviour
• Rats are exposed – on separate occasions – to two different stimuli & food is provided in association with only one of them
• both stimuli appear simultaneously but no food shows up –> although the animals do not need to do or learn anything, they nevertheless spend more time near the stimulus associated with the food
• rats with lesions of the central nucleus of the amygdala (CeA) fail to show approach behavior
-Study: neuronal activity in rat’s BLA reflects stimulus–reinforcer associations, including positive ones!
7.2: What’s the evidence that the A also processes positive affect? –> human studies
-Study: right amygdala was selectively sensitive to faces that had been associated with emotional descriptions – either positive or negative (equally active)– compared with those with faces that had been associated with neutral information
o Study: images paired with a high, medium or low probability of food reward –> subjects expressed a preference for images paired with a high reward probability, although they remained unaware of the relationship between the images & food probability
–> anterior temporal lobe resection (including A): did not display such preferences
7.2: What’s the evidence that the A is NOT essential in stimulus reward learning?
- -> A seems to have crucial role in emotional reactions & only conditional one in reward processing
- -> amygdala is essential for linking objects with the current value of food rewards
- -> to the extent that an affective tag from the amygdala provides this value signal, the amygdala contributes to stimulus–reward association
So, what’s the (conditional) role of A in stimulus-reward learning?
- A seems to have crucial role in emotional reactions & only conditional one in reward processing
- A: affective tag provides a value signal for rewards
7.3: Explain the neuro-economics experiment described by De Martino et al. (2006)- AIM
Investigated neural basis of framing effect with fMRI & a financial decision-making task
7.3: What’s loss aversion?
=tendency to prefer avoiding losses to acquiring equivalent gains
=phenomenon where a real or potential loss is perceived as psychologically or emotionally more severe than an equivalent gain
7.3: How is loss aversion implemented in the task used?
-two different frames would lead to same amount of money when deciding for sure option (‘Keep 20$’ same as ‘Lose 30$’ of 50$ in total)
7.3: What are the main findings in De Martino’s experiment (regarding amygdala, MCC/preSMA & vmPFC)?
- Amygdala activation mediates framing effect –> more active when participants choose in accordance with framing effect (gain-sure & loss-gamble)
- MCC/pre-SMA: more active when subjects decision is counter framing effect
- OMPFC/ vmPFC: more active in subjects that act more rationally (against framing effect)
- -> strong reciprocal connections between amygdala & OMPFC
7.3: How do De Martino’s findings about the amygdala
confirm Murray’s hypothesized role for amygdala in goal-directed decision making?
-Amygdala: key role in processing contextual positive or negative emotional information presented by frame
–> through amygdala-omPFC route, frame-related value information is incorporated
==> evidence for amygdala-OFC pathway as suggested by Murray
7.3: What’s the framing effect?
human choices are susceptible to manner in which objects are presented
