lecture 16 LOs

Question 1

reinstatement paradigm for relapse in animal models

Answer 1

1. train rats to administer drug (cues can be presented with drug infusion)
2. take rat through extinction (lever press no longer delivers drug or cue, rat stops pressing)
3. on test day no drug is provided but reinstatement of lever pressing can be induced by a drug prime, or a stressor, or a drug associated cue

Question 2

what can a drug taste, drug related cue, or stress do to lever pressing

Answer 2

it can increase it in the absence of drug administration

Question 3

what brain areas are the ability of the triggers (stressor, drug taste, drug associated cue) mediated by in the DA system

Answer 3

PFC, accumbens, amygdala

Question 4

how do addictive drugs affect mesolimbic DA levels

Answer 4

dramatically increase the DA levels
DA doesnt mediate pleasure, but it does play a major role in wanting

Question 5

what do drug induced increases in DA do to your brain

Answer 5

trick it into thinking that smth important is happening so it starts making associations with the environmental cues linked w drug taking

Question 6

what does reward associated cues increasing DA release into the accumbens do

Answer 6

triggers the same behaviours that got you the rewards in the first place (aka drug seeking)

Question 7

what can prolonged drug use do to the brain

Answer 7

induce a hyperactive (or sensitized) DA system
increased DA transmission can amplify the effects that drug-related cues exert over behaviour

Question 8

what is the DA and addiction incentive sensitization hypothesis

Answer 8

cues associated with drug taking take control over behaviour
initial drug taking driven by pleasurable drug effects
over time tlerance develops to hedonic effects (you start to like the drug less)
however, effects on the DA system and the learning about drug related cues becomes sensitized

Question 9

what happens to the associative memories between the drugs effect and their related cues in a hyperdopaminergic state

Answer 9

amplification
drug cues trigger more craving and then more drug taking, even if the effects of the drug aren’t as pleasurable

Question 10

what is DA sensitization w repeated drug use

Answer 10

repeated drug use makes the DA system more responsive to drug related cues and stress
this results in changes in neural networks (rather than just DA neurons) that include the VTA, PFC, and the NAc
enhanced DA is thought to promote craving and drug seeking behaviours in response to triggers (like stress or drug related cues)

Question 11

what would within system adaptations of neuroadaptations with repeated drug use result in

Answer 11

down regulation of reward circuitry (tolerance to pleasurabe affects of drugs)

Question 12

what would between system adaptations and gradual recruitment of the anti reward system do in neuroadaptations with repeated drug use

Answer 12

stress and adversion related circuits that include NE, peptide transmitters, and dynorphin, the central nuecles of the amygdala and the NAc

Question 13

what is physical withdrawal

Answer 13

can contribute to drug cravings and maintenance of addiction, it cannot explain all aspects of the behaviour though

Question 14

initially what circuit do drugs activate

Answer 14

reward circuit promoting drugs positive reinforcing effects

Question 15

after repeated drug use what happens to drugs ability to activate the reward circuitry

Answer 15

drugs become less effective at it

Question 16

as drugs become less effective at activating the reward circuitry, what else happens

Answer 16

the acitvation of the anti-reward system increases, involving the release of NE, CRF, and dynorphin

Question 17

what are the two major functions of the anti-reward system

Answer 17

mediates some of the aversive effects of stress
puts a limit on reward functions

Question 18

when is the anti-reward system activated

Answer 18

during withdrawal
plays a major role in the aversive effects and the negative emotional states (ex depressed mood)

Question 19

what does the anti-reward and reward circuitry theory propose

Answer 19

that drug addiction is driven by motivation to alleviate negative emotional states associated w withdrawal

Question 20

what happens with the positive and negative effects of drugs w repeated use

Answer 20

positive effects get shorter and weaker
negative effects get larger and last longer

Question 21

what type of abnormalities have been found in drug addicts

Answer 21

PFC structural and functional abnormalities

Question 22

what do MRI studies show about the grey matter volume in drug users

Answer 22

reduced grey matter, sometimes even after long periods of abstinence
we don’t know if this is a predisposition to drug addiction or if its caused by addiction or even both

Question 23

what does imapired PFC function in addicts result in

Answer 23

impaired flexibility and increased impulsivity
may also contribute to intrusive thoughts and cravings of drug taking

Question 24

what happens to the D2 receptors in addicts

Answer 24

they have fewer D2 receptors
are proposed to serve as a brake function on certain actions

Question 25

does alcohol enter the brain

Answer 25

yes

Question 26

what do lower doses of alcohol do

Answer 26

disinhibition, euphoria, relaxation

Question 27

what do higher doses of alcohol do

Answer 27

slurred speech, impaired motor coordination and memory

Question 28

how does alochol effect neural activity at higher and lower doses

Answer 28

lower: preferentially suppresses inhibitory interneurons and has stimulant (dishinhibitory) like effects
higher: causes broad suppression of cortical pyramidal neuron activity

Question 29

how does alocohol diffuse in the body

Answer 29

across membraines of GI tract into the blood
greater alcohol concentration consumer results in more rapid diffusion

Question 30

what is alcohol metabolized by

Answer 30

alcohol dehydrogenase (in the liver and gastric fluid)