3-addiction and brain

Question 1

what is the concept/question of abuse potential

Answer 1

are some drugs more likely to result in addiction/dependence than others?

Question 2

what do drugs of abuse do to the reward pathway (basic)

Answer 2

artificially manipulate/”hijack” the reward pathway

Question 3

what is reinforcement

Answer 3

a behavioural event followed by a consequent event such that the behaviour is then more likely to be repeated

Question 4

what is a fixed ratio schedule (in studying the strength of reinforcement properties of a drug)

Answer 4

animal is required to perform behaviour a specific number of times to achieve reward

Question 5

what is a progressive ratio schedule (in studying the strength of reinforcement properties of a drug)

Answer 5

animal is required to perform an increasing number of responses for subsequent reward

Question 6

what strongly correlates with abuse/addiction potential of drug

Answer 6

a high strength of reinforcing property

Question 7

what is extinction

Answer 7

reduce the drug seeking behaviour ti zero by removing the reward/drug

Question 8

what is a good way to test how far an animal is willing to go to get the drug? (2 main things)

Answer 8

start with fixed-ratio schedule then move to progressive ratio schedule (it may have to perform the same task hundreds of times)

Question 9

what is the reinstatement paradigm

Answer 9

the measure of vulnerability to relapse into drug abuse

Question 10

how do they do the reinstatement paradigm in experiments (4 steps)

Answer 10

• animals trained to self administer
• extinguish behaviour by discontinuing drug
• animal gives up on behaviour
• test different stimuli to see what will cause the animal to reinstate drug seeking behaviour (even tho no drugs there)

Question 11

what are the main things that cause reinstatement in humans (3)

Answer 11

stress
small dose of drug
drug associated cues

Question 12

what is conditioned place-preference experiment

Answer 12

-room with specific colours is where they administer drug. then later they see if the animal will go back to that one or a neutral room

Question 13

what does it mean if the animal prefers the drug associated chamber

Answer 13

drug is probably reinforcing

Question 14

what does it mean if the animal prefers the neutral chamber

Answer 14

drug probably has a negative effect

Question 15

what does it mean if the animal doesnt prefer the neutral chamber or the drug associated chamber

Answer 15

the drug probably has no effect

Question 16

what do all strong reinforcer drugs have in common

Answer 16

all stimulate dopamine release in certain regions of the brain

Question 17

what is in vivo microdialysis

Answer 17

implant a probe (stereotaxic surgery) in specific brain region and collect fluid to analyze its neurotransmitter levels

Question 18

what did microdialysis dopamine measurements tell us about natural vs drug induced dopamine release

Answer 18

a lot more dopamine is released via drugs rather than naturally stimulating things

Question 19

what does a bigger dose of drugs do to the amount of DA released in the nucleus accumbens

Answer 19

increases DA release

Question 20

what is fast-scan cyclic voltammetry and how does it work

Answer 20

captures rapid dopamine release (in concentrations) within seconds
measures the oxidation of dopamine (loss of e) when low voltage is applied to probe

Question 21

what is a downside to in-vivo microdialysis

Answer 21

it is slow (minutes to get info) so you may miss important info and you have to pump fluid back into the brain

Question 22

what does quinine do to dopamine release and why

Answer 22

it is an aversive stimuli, so it decreases basal release of dopamine

Question 23

what is electrophysiology / how does it work

Answer 23

measures the activity of neurons that are releasing dopamine by implanting electrodes to measure the change in electrical properties of neurons

Question 24

what 2 things makes electrophysiology great

Answer 24

fast

can measure electrical response of individual neurons

Question 25

what are the 3 techniques for measuring dopamine in the brain

Answer 25

microdialysis fast-scan cyclic voltammetry electrophysiology

Question 26

what is the technical name of the reward pathways (2 and the combined name)

Answer 26

mesolimbic mesocortical mesocorticolimbic

Question 27

what is the major neurotransmitter of the mesocorticolimbic pathway

Answer 27

dopamine

Question 28

why can you link the mesolimbic and mesocortical pathway into the mesocorticolimbic pathway

Answer 28

most drugs indirectly or directly stimulate components of these pathways

Question 29

what happens to drug use if you disrupt the mesolimbic pathway

Answer 29

prevents self-administration (and blocks dopamine receptors) also causes anhedonia (no more happy)

Question 30

why cant you treat drug addicts by disrupting the mesolimbic pwahway

Answer 30

you get anhedonia (no more pleasure) and motivation loss

Question 31

where is dopamine released

Answer 31

the ventral tegmental area VTA

Question 32

where does dopamine from the ventral tegmental area release onto

Answer 32

nucleus accumbens amygdala hippocampus prefrontal cortex

Question 33

what happens with increased dopamine in the nucleus accumbens

Answer 33

reward and euphoria (pleasure centre)

Question 34

what is the role of the amygdala and hippocampus

Answer 34

memory

Question 35

what is the role of the prefrontal cortex

Answer 35

higher cognitive function

Question 36

is dopamine excitatory or inhibitory

Answer 36

both, depending on what type of dopamine receptor it interacts with

Question 37

is GABA excitatory or inhibitory

Answer 37

inhibitory

Question 38

what does it mean for a neurotransmitter to be inhibitory

Answer 38

it decreases the probability of depolarization

Question 39

is glutamate excitatory or inhibitory

Answer 39

some are excitatory | some presynaptic ones are inhibitory (negative feedback system for glutamate release)

Question 40

what neurotransmitter is responsible for anticipating and receiving drugs, euphoria and behaviour reinforcement

Answer 40

Dopamine

Question 41

what is phasic dopamine release | and the average #

Answer 41

burst of DA release in response to something | midbrain dopamine neurons firing at 20/sec

Question 42

what is tonic dopamine release | and the average #

Answer 42

background/basal level of constant DA release | midbrain dopamine neurons firing at 1-5/sec

Question 43

what centres are involved in the mesolimbic pathway

Answer 43

VTA sending out to the nucleus accumbens, the amygdala and the hippocampus

Question 44

what kind of behaviours are associated to the limbic system

Answer 44

primitive emotional behaviours

Question 45

what centres are involved in the mesocortical pathway

Answer 45

VTA to the prefrontal cortex

Question 46

what parts of the brain respond to the dopamine message by sending out glutamate? And to where?

Answer 46

- PFC, VTA, amygdala, hippocampus and PFC to nucleus accumbens - PFC to VTA - amygdala to VTA - hippocampus to PFC

Question 47

what are 95% of the neurons in the nucleus accumbens

Answer 47

medium spiny neurons (MSNs)

Question 48

where are the medium spiny neurons

Answer 48

ventral portion of the nucleus accumbens

Question 49

what do medium spiny neurons release when depolarized

Answer 49

GABA

Question 50

what are the 2 major divisions of medium spiny neurons? | where are they found?

Answer 50

ones with D1 and D2 receptors | on two different output paths from the nucleus accumbens

Question 51

what is the difference with D1 and D2 receptors

Answer 51

D1=excitatory | D2=inhibitory

Question 52

what does activation of D1 and D2 do

Answer 52

it usually results in increased locomotion (Even though they are 50/50, they still overall cause excitation)

Question 53

what are the cortical and dopamine afferents from that connect to the medium spiny neurons

Answer 53

cortical afferents from prefrontal cortex | dopamine afferents from the VTA

Question 54

what modulates the activity of medium spiny neurons

Answer 54

dopamine, glutamate and other neurotransmitters

Question 55

what part of the brain become most activated in the presence of drug associated cues

Answer 55

amygdala and hippocampus

Question 56

what parts of the brain seem to be a major component of craving

Answer 56

amygdala and hippocampus due to memories of drug - fires up the whole reward pathway

Question 57

how can you reinstate drug-taking behaviour in animals even after extinction

Answer 57

by stimulating the hippocampus

Question 58

what neurotransmitter(s) are involved with acute drug effects

Answer 58

dopamine

Question 59

what neurotransmitter(s) are involved with chronic drug effects

Answer 59

glutamate and dopamine

Question 60

what happens with acute drug taking to the nucleus accumbens

Answer 60

flooded with dopamine, gives euphoria and reinforces drug taking behaviour

Question 61

what happens with acute drug taking to the hippocampus and amygdala

Answer 61

memory centres create a strong emotional memory(overlearning), may be responsible for craving and relapse

Question 62

what is overlearning

Answer 62

learning abnormality caused by drugs-so much dopamine that these memories are deeply engrained and have priority over other important memories - minor cues can trigger these major drug memories

Question 63

what does chronic drug use do to glutamate signalling

Answer 63

changes the strength of glu signalling between pathways,

Question 64

how is the PFC effected from chronic drug use (neurotransmitters)

Answer 64

abnormal glutamate and dopamine signalling causes a loss of behavioural control and decision making

Question 65

in what way has glutamate signalling become altered (where)

Answer 65

signalling from PFC, amygdala and hippocampus to the nucleus accumbens