Neurophysiology of Reward and Addiction

Question 1

What is motivation?

Answer 1

Process that mediates goal-directed responses or goal-seeking behavior to changes in the external or internal environment

Question 2

What is saliency?

Answer 2

Something important in the surrounding environment worth paying attention to

Question 3

What is reward?

Answer 3

Objects, stimuli, or activities that have positive value

Question 4

What is aversion?

Answer 4

A negative reinforcement of behavior that the individual will learn to avoid future encounters

Question 5

What is pleasure?

Answer 5

Positive sensation often referred to as euphoria or hedonia

Question 6

What is the purpose/function of pleasure?

Answer 6

Promote behaviors that are consistent with survival of self and the species; these natural rewards are elicited by behaviors which may include caring for young, palatable food, mating, and exercise or activity

Question 7

How do drugs of abuse work?

Answer 7

Increase extracellular dopamine concentrations in limbic regions, including the nucleus accumbens; they also provide longer and larger increases in dopamine than natural reinforcers such as food and sex

Question 8

What are some drugs that increase dopamine directly? How do they do this?

Answer 8

Cocaine, amphetamine, methamphetamine, ecstasy; work by inhibiting dopamine reuptake or promoting dopamine release

Question 9

What are some drugs that work indirectly? How do they do this?

Answer 9

Nicotine, alcohol, opiates, marijuana; work via other neuron receptors that modulate dopamine levels

Question 10

What can activate the VTA?

Answer 10

EAA, ach, orexin, opioids

Question 11

What does chronic drug exposure cause?

Answer 11

Alters morphology of neurons in dopamine-regulated circuits; at the cellular level, drugs can alter the expression of certain transcription factors as well as a wide variety of proteins involved in neurotransmission in brain areas regulated by dopamine

Question 12

What is fear conditioning?

Answer 12

Learning that one behavior is associated or leads to something unpleasant or aversive

Question 13

Describe how a non-addicted brain works

Answer 13

Saliency of substances and substance cues should be low in the non-addicted brain because the brain inhibits the drive to seek such substances

Question 14

Describe how an addicted brain works

Answer 14

Saliency of substances and substance-related cues is increased, which overrides the PFC’s control of behavior; PFC can no longer inhibit the drive to seek substances

Question 15

What is the function of the amygdala in terms of dopamine?

Answer 15

Retrieval of fear memories

Question 16

What is the function of the VTA in terms of dopamine?

Answer 16

Signals prediction error between expected outcome and actual reward experienced

Question 17

What is the function of the nucleus accumbens in terms of dopamine?

Answer 17

Assignment of salience to certain stimuli and mediate decisions that seek (or avoid) a desirable (or aversive) situation

Question 18

What is the function of the hippocampus in terms of dopamine?

Answer 18

Provides place and direction-contextual information about environment in which stimuli is experienced

Question 19

What is the function of the substantia nigra and dorsal striatum in terms of dopamine?

Answer 19

Motor response associated with navigating the environment toward a desirable cue with the goal of engaging in the activity that elicits reward