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Flashcards in Reward - Drug Abuse Deck (37):
1

Function in reward and reinforcement as part of a neural circuit that interfaces between limbic emotional-motivational information and extrapyramidal regulation of motor behavior.

Ventral Tegmental Area (VTA) and nucleus accumbens:

2

____________ is Central to Reward

Dopamine

3

Critical integrative structure projecting to the VTA and the nucleus accumbens. Thought to be important to the formation of stimulus-reward associations (i.e., remembering the pairing of stimulus with reward).

Amygdala

4

Drugs of abuse usually:

Affect DA

5

Certain regions are critical for executive function in providing control over impulses from destructive behavior. Their impairment in humans following chronic drug abuse appears to be an important mediator in the loss of control over drug intake (addiction).

Prefrontal cortex:

6

a stimulus that the brain interprets as intrinsically positive or something to be approached.

reward

7

A _____________ is one that increases the probability that behaviors paired with it will be repeated

reinforcing stimulus

8

Central Role of Dopamine Release from VTA into NA: Final common pathway of reinforcement and reward is hypothesized to be the mesolimbic dopamine pathway AKA ___________

– ventral tegmental area to nucleus accumbens.

9

VTA releases DA into

Nucleus Accumbens

10

Reactive Reward System: Consists of the VTA (dopamine cell bodies), the nucleus accumbens (where DA neurons project) and the amygdala (which connects to both the VTA and NA).

x

11

Physiologic Role of Reward Pathway
Normal function

Mediate pleasure perception (reward) and strengthen behaviors (reinforcement) associated with natural reinforcers

Produces motivational states that modulate physiological-behavioral responses ensuring survival and reproduction

Complementary pathway to networks for learning about dangerous stimuli (fear)

12

Physiologic Role of Reward Pathway Reward:

Stimulus interpreted as intrinsically positive – something to be approached

13

Drug-induced pleasurable states are strong motivators of initial drug use

Hijack normal Physiologic Role of Reward Pathway

14

Reactive Reward System: Consists of the VTA (dopamine cell bodies), the nucleus accumbens (where DA neurons project) and the amygdala (which connects to both the __________).

VTA and NA

15

Major components of reward and reinforcement circuitry

Function as interface between limbic emotional-motivational information and extrapyramidal regulation of motor behavior

Ventral Tegmental Area [VTA]--> Nucleus Accumbens [NA]

16

Memory circuit that mediates associations between biologic stimuli (or drugs) and environmental cues

Hippocampus

17

Integrative structure that is critical to formation of stimulus-reward associations

Amygdala

Usues Glu at NA

18

Critical for executive function in providing control over impulses from destructive behavior - impairment important mediator of loss of control

Prefrontal Cortex

19

Prefrontal output to Na

Glu

20

NA projects to ____ using GABA

Thalamus

21

The more intense and more direct this effect on DA release --> ___________

greater the addiction potential of the drug

22

Amygdala to VTA functions to signal prospect of pleasure-reward (relevance detection) from ________ and provides motivational state to achieve it

natural reinforcers

23

Drug-induced DA release (__________) is more explosive (pleasurable) than with natural reinforcers

VTA to NA

Drugs skip the learning natural pathway

24

Repeated drug exposures result in __________ to trigger drug-seeking behavior when presented with drug cues

pathologic learning (VTA to amygdala)

25

Amygdala to NA signals triggering of emotional memories by drug cues that then initiates ________

behavior to seek and take drugs

26

Drug Addiction thus “hijacks” the ______________

normal reward circuitry

27

Prefrontal cortex to nucleus accumbens
Orbitofrontal

regulating impulses

28

Prefrontal cortex to nucleus accumbens
Dorsolateral

analysis of situation

29

Prefrontal cortex to nucleus accumbens
Ventromedial

integration with emotions

30

Variables Influencing Drug Abuse Pharmacokinetics
Rate of Onset of Action
~highly addictive

Abuse liability increased with faster of onset of action

Inhalation
Intravenous

31

Onset of effects within 15-30 sec

IV

32

Onset of effects within 7 sec

Inhalation

33

Most dangerous route

IV

34

Easiest route of administration – onset of effects delayed 20-30 minutes
Difficult to obtain rush feelings via this route

Oral

35


Most commonly via insufflation – effects within 3-5 minutes

More rapid and intense than oral (bypasses liver)

Mucous membrane absorption

36

Termination of Effects

Withdrawal effects more severe for drugs with short half-lives

Leads to continued drug administration simply to prevent withdrawal

Heroin (short t1/2) more addicting than methadone (long t1/2)

37

For a drug-dependent individual, the more rapidly the target-receptor becomes __________, the more severe the withdrawal effects

unoccupied by drug