Problem 6 Flashcards
Adaptive decision making
Involves selecting the most valuable option
–> typically by taking an action, which ofc involves value comparison
OFC
Plays a critical role in value based choices between stimuli, but not actions
–> learning stimulus-value
dACC
Plays a critical role in value based choices between actions
–> learning action-value
- WHICH outcome is expected from a particular action ?
- Is this action WORTH executing, based on the value + cost of the outcome
THUS: lesions will lead to reward-guided action selection deficits
What do the findings that action value vs stimulus value learning is controlled by different brain regions mean for decision making processes in general ?
That stimulus-values represented in the OFC are not necessary for generating action-values in the dACC and vice versa
–> while they may interact, there is no link between these forms of adaptive decision making choices
It is argued that the ACC, like the lateral PFC is involve in executive control.
How profound is that involvement though?
ACC is only activated when there is
- change in response
- conflict between possible responses
BUT: not active when only the stimulus selection is at issue
–> lesions here, thus only cause little disruption of WM
What do patients with ACC lesions show ?
What is consequently the main role of the ACC ?
- Inability to correct ones own mistakes/ learning from them
- ACC is involved in performance monitoring for mistakes
Event related negativity
ERN
- Can be recorded after an erroneous response occurred
- -> immediate corrective signal - Reflects the importance a subject places on avoiding mistakes
–> ERN increases with emphasized accuracy, thus has an evaluative role
THUS: since it predicts the nonoccurrence of a reward, there is decreased phasic dopamine release
Activity of the ACC is associated with…
- Reductions in reward
- Error detection
–> lesions lead to disrupted reward-related action selection
Why does response conflict elicit SFG activity even when it does not lead to an error response ?
Activation of the SFG shows how the need for cognitive control is detected before mistakes are made
Activity of the caudal Superior frontal gyrus (cSFG) is associated with …
- Changing response sets
- Response conflict
–> thus representations of more than one response are co-activated
BUT: must not necessary lead to an error response
The ACC works in conjunction with another brain substrate to mediate cost benefit decisions.
Name the brain region.
Ventral striatum
–> involved in reward processing
What neural structures generate ERN signals ?
dACC, but also surrounding pMFC and
- rACC
- dlPFC + vlPFC
- lateral parietal cortex
BUT: dACC/pMFC are principal generators of the ERN signal
–> thus key part of error-processing system
What happens if a person makes an error without being aware of it ?
How does it show in ERN signaling ?
There is no ERN signal
–> subjects will have lower expectations for a correct response to degraded stimuli, thus personal investment is lower
AND: ERN signal reflects the effort a person puts in responding correctly
Error positivity
Pe
Generated by parietal cortex
–> follows the ERN
How can obsessive compulsive disorder be related to ERN ?
OCD patients have a defect in their error monitoring systems
–> confirmed by larger ERNs in OCD patients
THUS: abnormalities in performance monitoring may establish a vulnerability for OCD
