Addiction

Question 1

When thinking of behaviors of motivation, think of what neurotransmitter?

Answer 1

Dopamine

Question 2

Describe the physiology purpose of pleasure?

Answer 2

Motivation, reward, and promote behaviors of survival

Question 3

4 major systems use DA and what are their main functions?

Answer 3

Substantial nigra - motor
Mesolimbic - VTA to NA, pleasure, reward and addiction
Mesocortical - VTA to frontal cortex, attention, high level of consciousness
Tuberinfundivular - Hypo to anterior pit. DA suppresses release of prolactin

Question 4

3 brain regions relating to reward she wants us to focus on?

Answer 4

VTA, NA and prefrontal cortex

Question 5

6 NT systems to know?

Answer 5

DA
GABA
Opioids
EAA
Dynorphin
Orexin

Question 6

Explain the interaction of the VTA to the NA?

Answer 6

Dopamine projections to the NA
Dopamine released in the NA leads to inhibition
NA activity decreases leading to pleasure

Question 7

What 3 structures activate the VTA and with what NTs?

Answer 7

Prefrontal cortex - EAA
Other nuclei with Ach or EAA
Lateral nucleus using orexin (food)

Question 8

What is the interaction of NA to PFC?

Answer 8

NA projects GABA neurons that release GABA in the PFC

Activating the NA prevents pleasure

Question 9

What 3 structures activate the NA and with what NT?

Answer 9

Hippocampus, amygdala, and PFC all via EAA

Question 10

How does the NA shut off the VTA?

Answer 10

GABA neurons release GABA back to the VTA which binds to kappa opioid receptors to suppress DA release

Question 11

Explain the dopamine reward system?

Answer 11

Addictive drugs activate the DA system which releases DA at the NA. This means that opioids can activate the VTA. They do this by inhibiting GABA neurons in the VTA via mu receptors increasing

Question 12

Explain the concept of reward prediction?

Answer 12

DA neurons encode the discrepancy between reward predictions and the actual reward itself. When there is an unpredicted reward, there is activation of dopamine. When there is a fully predicted reward there is no response. Where there is a lower reward than expected, there is a depression of dopamine.

Question 13

Explain attention to cues in the following structures?
VTA to prelimbic cortex?
VTA to amygdala?
VTA to orbitofrontal cortex?

Answer 13

Promotes attention toward cues that are good predictors of reward
Cues that inconsistently predict an outcome
Promotes attention towards cues that are very noticeable even if they inconsistently predict reward

Question 14

Big difference between drugs and natural rewards and how they affect the reward system?

Answer 14

Drugs just continue to reinforce drug related cues, behaviors and rewards.
Natural rewards produce signals until the predictions match the actual events

Question 15

Explain the difference of activation of the pleasure pathway normally and by drugs?

Answer 15

Normally there is stimuli for physiological needs that release dopamine and the reward is pleasure associated with these needs. Eat, sex for kids, etc.
The way that drugs interact with the brain, they cause an enhanced release of dopamine that is not proportional to the stimulus, we just think it is because of all the dopamine. The reward is euphoria that is exaggerated to an otherwise mild stimuli

Question 16

How do we define long term potentiation?

What is the mechanism?

Answer 16

Persistent increase in synaptic strength following high frequency stimulation of a synapse

Increased phosphorylation of AMPA receptors and insertion of additional AMPA receptors into post synaptic cells.
Eventual activation of calcium calmodulin CREB mechanism

Question 17

CREB leads to what in the NA and what in the locus Ceruleus?

Answer 17

Dynoprhin in the NA

Physical dependency in the LC

Question 18

FosB and AP1 upregulate the expression of what 3 things?

Answer 18

EAA receptor expression (AMPA and NMDA)
Elements of cell signal transduction
Factors promoting drug seeking, motivation, and locomotion

Question 19

NFKAPPABETA induces which brain structure to do what and increases what?

Answer 19

NA to grow dendritic spines. Increases drug reward.

Question 20

Physical dependence is due to excessive what due to what mechanism?

Answer 20

Nor adrenergic output from the locus ceruleus due to CREB dependent upreguation of target genes in the LC

Question 21

What do D1 receptors lead to?

What do D2 receptors lead to?

Answer 21

Activates/promotes pleasurable feelings, motivation and recreate the activity

Attenuates euphoria, drug seeking and motor activity

Question 22

What mechanism induces associative learning?
What mechanism reflects expectation of reward?
What is the difference in DA firing of natural reinforces vs. drugs?

Answer 22

DA increases that are sufficiently large to active D1 recptors, as by drugs, can induce associative learning.

Conditioning triggers phasic DA firing in the VTA results in phasic DA in NA that is the person expecting reward

Natural reinforcers cease phase firing when the event concludes but drugs continue DA release

Question 23

Explain conditioned responses and cues for reinforcement?

Answer 23

Conditioned response can be powerful cues, especially social circumstances. Also drug associated cues like the people involved. Fear of withdrawal can be a very powerful cue.

Question 24

Self administration is what?

What is conditioned place preference?

Answer 24

Function of the reinforcement value of drug

Preferring the environment associated with reward