L24 - Decision-Making 2 Flashcards
What model is this?
The classic basal ganglia model for action generation
Define “agonist”
a substance which initiates a physiological response when combined with a receptor.
Define “antagonist” (biochemistry)
a substance which interferes with or inhibits the physiological action of another.
In the classical basal ganglia model, are both pathways activated at the same time or is only one pathway activated at a time?
Both are activated at the same time, however the pathway with the strongest total output is what determins whether the output will be performed.
human beings basal ganglia model is unique to them.
True or False.
False
Very ancient system that belongs to many animals (very adaptive to learn from punishment and rewards)
How do we test “go and no-go learning”?
Show them a set of symbols that have a chance of giving correct or incorrect feedback (reward or punishment).
Record which symbols they prefer choosing.
In go and no-go learning tests, how do we determine if someone is learning from reward or punishment?
Reward: they choose the stimulus with the highest proportion correct
Punishment: They avoid the stimulus with the lowest proportion correct
- choose A = Go learning*
- Choose B = No-Go learning*
Does positive feedback influence Go or No-Go learning?
Go learning
D1 receptors need more dopamine to work, positive feedback boost dopamine levels
How did psychologists Frank & O’Reilly (2006) test the basal ganglia model using young healthy individuals
Shifting the balance between the direct and indirect pathways with dopamine agonists and antagonists
Gave either drug or placebo
What happens to young healthy individuals when they are given haloperidol (+ dopamine)
Perform better with “go” learning and worse with “no-go” learning
What happens to young healthy individuals when they are given cabergoline (decreased dopamine)?
They perform better at “no-go” learning (negative feedback) and worse at “go” learning (positive feedback)
Drugs of abuse that boost dopamine levels can lead to what type of mental changes?
Impulsivity
Induce psychosis and schizophrenia
(these disorders are characterised by high levels of dopamine in the midbrain)
Most of our DNA is identical between different people, but some parts of our DNA differ.
What are these called?
Mutations
How many DNA strands does each DNA have?
Two
How many possible genotypes do we have?
3
Because we have two strands, we can either have C+C - T+T - C+T
Upon which chromosomes are DRD1 and DRD2 on?
DRD1 = 5
DRD2 = 11
not really important
Individuals who possess a genotype that increases neurotransmission via dopamine D1 receptors are better at learning through
Go learning
Individuals who possess the T/T genotype that increases expression of the DRD2 gene are better at what type of learning when compared to those who don’t have the mutation.
No-Go learning
Negative feedback
they have a higher density of dopamine D2 receptors
How are genetics related to learning?
Genetics influence the capability to produce the receptors (D1/D2) that are necessary to learn through reward or punishment
In the Baetu et al. (2015) study where they tested those with different DRD1 genotype and DRD2 genotypes ability to learn a motor sequence learning task -
What did they find happened to those with A1/A1 genes that are associated with lower dopamine D2 receptors?
They found it very difficult to learn from punishment
What type of genotype has been shown to be related to those with addiction (e.g. obesity)
Why?
Those with genotypes associated with lower dopamine D2 receptors.
Theyfind it much harder to learn from punishment and therefore they are more likely to become addicted to the positive effects of the habit without learning from the negative effects
What happens to our dopamine levels as we age?
What result does that have in our basal ganglia?
Declines
Stronger activity in the indirect pathway
Increases in stress and anxiety in older individuals is linked to…
The decline in dopamine levels
Older seniors over the age of 77 are better at _____ learning than younger seniors
no-go learning (negative feedback)
How is dopamine related to Parkinson’s disease?
Dopamine is drastically reduced for people with parkinsons when compared to healthy individuals
There is stronger activity in the indirect pathway for those with Parkinson’s disease, how can this be reversed?
With dopamine agonist medication
What type of disorder is Parkinson’s disease classified as?
Motor Disorder
What charactaristic cognitive changes happen to those with Parkinson’s disease?
Depression, anxiety and faster cognitive decline
People with Parkinson’s are better at what type of learning?
Far better at No-Go (punishment) learning than Go (reward) learning
When you give people with Parkinson’s dopamine agonist medication, what happens to their learning?
Improves Go learning and impairs No-Go learning
They recover well for their Go learning but it makes them reduce their ability for No-Go learning
What disorder do many Parkinson’s patients develop as a result of their dopamine agonist medication?
Impulse Disorder
Overly active “Go” learning and lack of “No-Go” learning when they are medicated.
How is dopamine related to tourette’s syndrome?
It is characterised by excessive dopamine in the midbrain
Same as ADD, impulsivity, obsessions, autism - high comorbidity
What is Tourette’s syndrome?
Involuntary or habitual movements or sounds (motor and vocal ticks)
They are usually preceded by the urge to perform them that they can’t control
Usually a child disorder but some go into adulthood
People with Tourette’s syndrome are better at which type of learning?
Go Learning
- Impaired No-Go Learning*
- Good at learning from reward, bad from punishment*
People with Tourette’s syndrome are typically given what kind of medication?
Dopamine antagonist medication
What happens to people with Tourette’s ability to learn when they are on medication?
They learn better from No-Go (punishment) than Go (reward) learning
It is reversed from their unmedicated state
Is Parkinson’s or Tourette’s better at learning from punishment (unmedicated)?
Parkinson’s
Good luck!
Negative thoughts are interpreted in the stratium as -
Punishment
You can learn motor movements by practicing them in your mind
True or False
True
If you have positive thoughts, what will happen to you?
Your brain will change for you to be more positive?
