Reward and Attention

Question 1

What is the dopamine process in learning?

Answer 1

• A reward to an action is anticipated; if the reward is met, dopamine is released
• Rewards released on a random schedule are the strongest way to reinforce learned behaviour

Question 2

Dopamine (DA)

Answer 2

Neurotransmitter that fires when something unexpected occurs
In midbrain (striatum), part of the reward prediction error system
Essential in learning, movement control, memory, attention, mood, cognition, and sleep

Question 3

How is dopamine related to addiction?

Answer 3

Habit-forming drugs cause many times more dopamine to be released than is usual; neural pathways between the reward circuit and prefrontal cortex are overrun, weakening the ability to tame impulses
- the more the drug is used, the harder it is to stop

Question 4

How is dopamine related to Parkinson’s?

Answer 4

Parkinson’s is caused by dopamine deficiency

• some Parkinson’s drugs cause gambling addiction because they flood the brain with dopamine

Question 5

Describe the two ways that dopamine is released

Answer 5

Fast: error signal
- precise, short, large spike in the amount of dopamine in a small region of the brain

Slow: motivation
- constant, low concentration of dopamine “sitting around” in many regions of the brain

Carried by separate sets of dopamine neurons

Question 6

How does an error signal in the reward system work?

Answer 6

Positive error: in your favour
- outcome is more favourable than prediction

Negative error: not in your favour
- prediction is more favourable than outcome

No error:
- outcome matches prediction

Question 7

What does the slowly changing concentration of dopamine signal?

Answer 7

How motivated a person is
- low concentration = low motivation

Signals neurons to commit to a course of action

Question 8

What is stimulus bound appetitive behaviour (Panksepp)?

Answer 8

Inclination to work towards a stimulus that satisfies bodily needs (goal-directed behaviour)
- desire
- anticipation

Question 9

What is incentive salience?

Answer 9

When a cue stands out because of its association with reward
- associations trigger wanting or craving, leading to automatic response of seeking system
- cues are attended to more in habitual way

Question 10

How is the nucleus accumbens region of the striatum related to reward?

Answer 10

Region of ventral striatum in basal ganglia
Key node in the mesolimbic DA system (the seeking system)

Dopamine is released onto neurons in the NAc when:
- you expect a reward
- you encounter an unexpected reward

Question 11

What emotional system (Panksepp) is related to the reward prediction error system (DA system)?

Answer 11

Seeking/approach
- emotions include desire, hope, anticipation

Question 12

How are the caudate nucleus and putamen regions of the striatum related to reward?

Answer 12

They work together to transfer information from the cortex to the basal ganglia

Involved in:
- decision making
- motivation
- motor control
- habit

Question 13

Where is dopamine produced?

Answer 13

In several brain nuclei
- substantia nigra
- ventral tegmental area (VTA)

Question 14

Tonic DA

Answer 14

Tonic dopamine: slow and sustained
- motivates action to work towards reward
- wanting/seeking

Question 15

Phasic DA

Answer 15

Phasic dopamine: fast bursts
- prediction error
- expectation of reward

Question 16

How is the caudate related to shifting covert attention?

Answer 16

Neural responses in the caudate tail are sensitive to learned value, so are important in value-based attentional capture (VDAC)
- the tail communicates with visual cortex to integrate

Question 17

Name three areas that modulate the visual cortex

Answer 17

• dorsal attention network modulates it for things that are task-relevant
• amygdala modulates it for emotionally relevant things
• caudate modulates it for reward