Reward and addiction

Question 1

What did Olds and Milner do to study motivation and reinforcement?

Answer 1

They implanted electrodes into the brains of rats and allowed them to press a lever to stimulate the brain with the electrode.

Question 2

What is electrical self-stimulation?

Answer 2

It is a behavior where rats press a lever to stimulate certain parts of the brain with implanted electrodes.

Question 3

Where are most electrical self-stimulation sites located?

Answer 3

They are located near ventral tegmental area (VTA) axons, which release dopamine.

Question 4

What is the source of dopamine for the mesolimbic pathway?

Answer 4

The ventral tegmental area (VTA)

Question 5

What did early thoughts suggest about the role of dopamine in motivation?

Answer 5

Early thoughts suggested that dopamine from VTA was thought to drive liking and pleasure and was released from palatable food, and animals were motivated to consume the palatable food for hedonic reward.

Question 6

What did Berridge and Robinson suggest about the neural systems controlling “liking” and “wanting”?

Answer 6

They suggested that “liking” and “wanting” were controlled by different neural systems.

Question 7

Is dopamine signaling necessary for “liking”?

Answer 7

No, according to Berridge and Robinson, dopamine signaling is not necessary for “liking” but is necessary for “wanting.”

Question 8

What is incentive sensitization?

Answer 8

Incentive sensitization is a theory that suggests that repeated exposure to drugs or other rewards sensitizes the brain’s reward system, leading to increased “wanting” of the reward.

Question 9

What is the difference between “liking” and “wanting” according to the text?

Answer 9

“Liking” and “wanting” are controlled by different neural systems.

Question 10

Is dopamine signaling necessary for “liking” or “wanting”?

Answer 10

Dopamine signaling is not necessary for “liking”, but is necessary for “wanting”.

Question 11

What does dopamine neurotransmission correlate more with according to the text?

Answer 11

Dopamine neurotransmission is correlated more with subjective ratings of wanting drugs than with “liking” ratings.

Question 12

What happens when dopamine cells in the midbrain are lesioned according to early studies?

Answer 12

Rats exhibit liking reaction to sweetness even in absence of motivation to consume food.

Question 13

What happens to dopamine firing when cues predict a reward according to microelectrode studies?

Answer 13

Dopamine firing increases even though the actual reward does nothing.

Question 14

What happens to dopamine firing when there is a lack of reward after a cue according to microelectrode studies?

Answer 14

Dopamine firing decreases.

Question 15

What is dopamine acting as in the brain according to the text?

Answer 15

Dopamine is acting as a feedback mechanism for the brain.

Question 16

How does dopamine firing change based on whether events are better than, worse than, or as expected according to the text?

Answer 16

If events are better than expected, dopamine increases. If events are as expected, there is no change in dopamine. If events are worse than expected, dopamine decreases.

Question 17

What happens to dopamine levels in the brain when events are worse than expected?

Answer 17

They decrease.

Question 18

What is the transition in addiction from goal-directed to compulsive habit?

Answer 18

Procedural memory - action, motor memory.

Question 19

What area of the brain is involved in goal-directed action-outcome responding in addiction?

Answer 19

Dorsolateral PFC.

Question 20

What is the effect of drug use on the prefrontal cortex?

Answer 20

Generally, the prefrontal cortex becomes hyperactive

Question 21

What is the difference between positive and negative reinforcement in addiction?

Answer 21

The feeling of the drug drives positive reinforcement, while negative reinforcement is driven by the desire to avoid the negative effects of withdrawal.

Question 22

What are some behavioral components of drug addiction in people?

Answer 22

Chronic irritability, emotional pain, dysphoria, increased stress reactivity, and loss of motivation for natural rewards.

Question 23

What are some behavioral components of drug addiction in animals?

Answer 23

Elevations in reward threshold, increases in anxiety-like behavior, and increases in stress reactivity.

Question 24

What is the cycle that characterizes addiction?

Answer 24

A cycle of escalation of drug intake, withdrawal, and negative affect that repeats.

Question 25

What is shold?

Answer 25

Escalation of drug intake.

Question 26

What are the behavioral effects of shold?

Answer 26

Increases in Anxiety-like behavior and Increases in Stress Reactivity.

Question 27

What is the cycle that characterizes addiction?

Answer 27

The cycle that characterizes addiction is the repetition of shold, leading to increased drug intake.