Task 5 Flashcards
5.1: Which part of the cerebral cortex is specialized for deciding on preferences for objects in the
environment based on their value?
prefrontal cortex (PFC)
5.1: Which three parts contribute to goal-oriented decision making in the PFC?
lPFC, OFC, MCC
5.1: What does the lPFC contribute to goal-oriented decision making?
- -> state representation
- represents utilities or values associated with states of environment
- Neurons encode sensory evidence to determine appropriate action
5.1: What does an increasing value of expected reward increases reliability of?
state representation
5.1: What does the OFC contribute to goal-oriented decision making?
–> value representation
5.1: What does the OFC predict in regards to goal-oriented decision making?
Predicts rewards expected from different options & cues based on learned stimulus-reward association
5.1: What does a lesioned OFC lead to in regards to goal-oriented decision making?
people are not able to adjust decision-making strategies when no longer successful (i.e., Wisconsin Card Sorting Task)
5.1: What does the MCC contribute to goal-oriented decision making?
- -> outcome evaluation
- Represents possible actions to obtain rewards & their value
- Outcome-related activity: update strategy after error
5.1: What does a lesioned MCC lead to regarding goal-oriented decision making?
Impaired ability to integrate outcome signals of previous choices for optimal decision making
5.1: What are utilities (neuroeconomics)?
- decision making is choosing between alternative choices in order to maximise the outcome
- -> each alternative can be assigned with a value which represents a preference
- 1: Why are neuro-economists interested in the “object-selection” part of the cortex?
- -> where do utilities get updated?
Each outcome has some value (a utility) and people make decisions to maximize these values
–> updating of utilities via lPFC, OFC & MCC
- 2: Rushworth’s model of goal-directed decision making
- -> model with most support (a-c)
-3 steps:
1. lOFC= learning precise value representations
associated with each good
2. mOFC/vmPFC –> value comparison
3. MCC –> action value comparison
5.2: Which evidence is there to support Rushworth’s model (a-c)?
- value difference signal in vmPFC
- double dissociation btw stimulus-reward
& action-reward associations
5.2: How does Rushworth’s model fit in the three-way division proposed by Lee et al. (2007)?
–> lOFC: learning & updating of value
representation (LEE: lPFC –> State Representation (environment))
–> vmPFC/mOFC: comparing of value representations (LEE: OFC –> Value Representation (expected outcome))
–> MCC: action value comparison / action selection (LEE: MCC–> Outcome Evaluation (action selection);
updates desirability of alternative option)
5.3: What does sensory-specific satiety mean?
= decrease of reward value is larger for the food eaten till satiety than for other foods
- 2: What is the difference to the first model proposed by Rushworth (a-b)?
- -> What’s the role of the mOFC/vmPFC & the MCC?
- mOFC/vmPFC: mainly involved in value expectations & NOT value comparison
- MCC: finally does value comparison (NOT action value comparison in this model)
- 3: Explain O’Doherty’s et al. experiment (sensory-specific satiety)
- -> methods
- Rate pleasantness & intensity of odor of banana & vanilla
- fMRI scan while PP were hungry & presented with odor
- Eat banana till satiety
- Rate again
- fMRI scan while PP were presented with the same odors
5.3: O’Doherty’s et al. experiment (sensory-specific satiety) –> rating results
pp rated banana significantly lower (less pleasant, negative) post-satiety than pre-satiety
5.3: O’Doherty’s et al. experiment (sensory-specific satiety) –> fMRI results
- Odor activated OFC
- -> Activation decreased in response to odor of eaten food (banana), but not to the other food (vanilla)
- -> In correspondence with pleasantness ratings
5.3: O’Doherty’s et al. experiment –> conclusion (OFC)
OFC may be involved in storing & updating stimulus-reward associations
- 3: OFC –> what’s special about what is stored there?
- -> What must arrive at OFC for updating to take place?
- what is stored is highly object & reward specific
- feedback signals must arrive at OFC in the brain for the updating to take place
5.3: O’Doherty’s et al. experiment –> what do results suggest about OFC? (Rushworth’s model?)
- in line with Rushworth’s model
- lOFC assigns values & updates these later after feedback from mOFC/vmPFC
5.4: Why would damage to the cerebral part of the reward system (in particular, vmPFC) lead to personality change?
- Disrupt value-guided decision making
- vmPFC –> important for self-perception & self-knowledge
5.4: What aspect of meaningful, goal-oriented behavior is lost or becomes difficult after damage to this part of the brain?
- self-perception
- value-guided decisions (e.g., Phineas Gage could not hold a job & showed dysfunctional social behaviour)
5.4: What does damaged OFC lead to?
- dysfunctional social behaviour
- usually OFC enables accurate insight into one’s behaviour
5.5: When is the Default Mode Network(=DMN) usually active?
- Wakeful rest, mind wandering, day dreaming,…
- „Baseline mode“
5.5: Which brain areas consist of the DMN?
mPFC, PCC, angular gyrus
5.5: What DMN node is relevant here? What functions are generally associated with this node?
- vmPFC: affective node
- Involved in self referential information processing
5.5: Why would this node (vmPFC) be relevant for goal-directed decision making?
- Essential role in goal-oriented decision making
- important for self-perception & self-knowledge
5.5: Why is vmPFC relevant for personality?
- „Value for the self“
- -> Important for knowing personal preferences – determine utility of an object
- Largely unconscious
5.5: What is the pattern of (de)activation of the DMN?
- Deactivates less when people make self-referential judgments
- When thinking about so else –> deactivates vmPFC more
5.6: Which evidence is there in support of the claim made by Rushworth that goal-directed decision making requires a division between selecting of objects & selecting of actions? –> STEP 1: value comparison
vmPFC/OFC
- lesions: not able to modify behavior; not as flexible in assigning values –> Iowa Gambling Task;
- dysfunctional social behavior
- cannot make decisions based on values for behavior
- represents cues of environment e.g., also social cues
5.6: Which evidence is there in support of the claim made by Rushworth that goal-directed decision making requires a division between selecting of objects & selecting of actions? –> STEP 2: action value comparison
- lesions in MCC: disrupts action-reward associations, but not stimulus-reward associations
- lesioned MCC: not able to integrate signals that are relevant for action selection outcomes
