Problem 8

Question 1

What happens when we get addicted

Answer 1

Drug hijacks the reward system of the brain, the Ventral tegmental area (VTA) to dopamine-sensitive cells in NA

Question 2

Dopamine

Answer 2

Important for reward so the most important factor of drugs travels from VAC to the limbic system and the prefrontal cortex (reward pathway) and generates there a feeling of reward
o Drugs lead to a lot of dopamine in the synaptic cleft which leads to an overstimulation
o The overstimulation makes the reward system less sensitive and is so less responsible for daily stimulants

Question 3

Role of striatum

Answer 3

o Dopamine is released in the dorsal striatum not by the drug itself but by stimuli associated with procuring and taking the drug
o As a result of the changes in the VTA, increased activation is seen in the brain areas that receive input from the VTA – including the ventral striatum, which includes the NAC, and the dorsal striatum, which includes the caudate nucleus and putamen
 the changes that make the behaviours become habitual involve the dorsal striatum

Question 4

Orexin

Answer 4

is synthesized in neurons in the lateral hypothalamus and released in many parts of the brain, including those that play a role in reinforcement (VTA, NAC and dorsal striatum)

Question 5

NAC/NA

Answer 5

nucleus accumbens

Question 6

CREB

Answer 6

regulates expression/activity of genes and thus overall behaviour of nerve cells
o When dopamine in NAC rises, cells increase production of cAMP which activates CREB
o CREB binds to genes triggering the production of the proteins they encode
o Sustained activation results in production of more proteins that weaken reward circuity
o As CREB activity declines, sensitisation kicks in and so does craving

Question 7

Delta FosB

Answer 7

transcription factor:
o Concentrations rise gradually in NAC and other regions during chronic drug abuse
o Remains stable in cells for weeks/months after drug administration thus maintains gene expression even after stopping
 Contributes to long-term increases in sensitivity in the reward pathways

Question 8

What happens during withdraw

Answer 8

basically the opposite effect of the consumed drug

Question 9

Drug tolerance

Answer 9

is a state of decreased sensitivity to a drug that develops as a result of exposure to it (reducing the amount of receptors)

Question 10

Cross tolerance

Answer 10

One drug can produce tolerance for another one when they act by the same mechanism

Question 11

Metabolic tolerance

Answer 11

tolerance that results from changes that reduce the amount of the drug getting to its site of action

Question 12

Functional tolerance

Answer 12

Tolerance that results from changes that reduce the reactivity of the sites of action to the drug

Question 13

Causes for tolerance

Answer 13

o Can reduce number of receptors
o Decrease the efficiency with which it binds to the existing receptors
o Diminish the impact of receptor binding on the activity of the cell

Question 14

Conditioned drug tolerance

Answer 14

refers to demonstrations that tolerance effects are maximally expressed only when a drug is administered in the same situation in which it has previously administered

Question 15

Physical addiction

Answer 15

One theory is that the addiction is basically only the fear of the withdraw which makes it more difficult to accomplish one

Question 16

Positive-incentive theory of addiction

Answer 16

the addicted person wants to obtain the positive effects of the drug so they keep taking it (craving for the positive-incentive) can be also called hedonic

Question 17

Role of the setting

Answer 17

• The theory is that conditional stimuli that repeatedly predict the effects of a drug come to elicit greater and greater conditioned compensatory responses; and those conditioned compensatory responses increasingly counteract the unconditional effects of the drug and produce situationally specific tolerance

Question 18

Exteroceptive stimuli

Answer 18

external public stimuli such as the drug-administration environment are conditional

Question 19

Conditioned stimuli (CS)

Answer 19

a certain place for example (predictive for the US)

Question 20

Unconditioned stimuli (US)

Answer 20

Drug use

Question 21

Conditioned response (CR)

Answer 21

• After the association between CS and US has established it can produce conditioned responses (CR)

Question 22

Extinction

Answer 22

When the addiction is gone the connection between CS and US is smaller but its not unlearned so it can still occur under certain circumstances
o This is then called relapse and appears when the participant gets reminded by drinking 1 glass alcohol f. ex.

Question 23

Positive reinforcement

Answer 23

When the response (reward) comes direct after the stimuli the reinforcement is most effective

Question 24

Amygdala

Answer 24

assesses whether an experience is pleasurable or aversive

 Should it be repeated or avoided?

Question 25

Hippocampus

Answer 25

records memories of experience

 Where, when, with whom

Question 26

Frontal regions

Answer 26

coordinate and process all this information to determine ultimate behaviour

Question 27

VTA-accumbens pathway:

Answer 27

tells the other brain centres how rewarding something is

 The more rewarding the more likely it is remembered, repeated