Week 4 - Addiction

Question 1

What is anhedonia?

Answer 1

Inability of experiencing pleasure

Question 2

What is hypodopaminergia?

Answer 2

Depletion of monoamine stores in the brain that can cause depressive-like symptoms

Question 3

Hypodopaminergia is linked to ________ and ____________.

Answer 3

Anhedonia

Hypofrontality

Question 4

What is hypofrontality?

Answer 4

Decrease in activation of prefrontal cortex, which compromises planning and decision-making

Question 5

According to Volkow ND et al (2007), what did the brain scans of alcoholics show?

Answer 5

DA decreased and reported reduced reinforcing effects of MP

Question 6

According to Volcow et al (1997), what id the brain scans of cocaine abusers show?

Answer 6

Decreased DA and reported reduced rewarding effects of MP

Question 7

What is a challenging problem in the neurobiology of drug addiction?

Answer 7

To understand why some individuals become addicted to drugs while others do not.

Question 8

What may be one of the keys to determining why some people become addicted to drugs while others do not?

Answer 8

Differences in reward circuits: dopamine levels and receptor levels

Question 9

What happens when there is an over-expression of D2 receptors in the NAcb in rats addicted to alcohol?

Answer 9

Reduces alcohol preference and alcohol self-administration

Question 10

What does a form on impulsivity in rats predict?

Answer 10

high rates of intravenous cocaine self-administration

Question 11

A form of impulsivity in rats predicts high rates of intravenous cocaine self-administration. What is this associated with?

Answer 11

Changes in dopamine (DA) function before drug exposure

Question 12

What did Dally et al find while using PET on rats and cocaine reinforcement?

Answer 12

D2/3 receptor availability is significantly reduced in the nucleus accumbens of impulsive rates that were never exposed to cocaine

Question 13

In humans, what were low densities of dopamine D2 receptors associated with?

Answer 13

Decreased metabolism in the orbitofrontal cortex, where metabolism in other regions (basal ganglia) was relatively normal.

Question 14

What psychological disorder is associated with decreased metabolic activity in the orbitofrontal cortex?

Answer 14

Obsessive-compulsive disorder (OCD)

Question 15

What neurotransmitter does Ritalin (ADHD drug) bind to?

Answer 15

Dopamine (DA) receptors

Question 16

Long-term addiction results in ____

Answer 16

Long-term adaptations to the dopamine system

reduced activity of dopamine

reduced experience of pleasure

Question 17

Low levels of D2 receptors are associated with……

Answer 17

Increased desire for drugs

Question 18

What are some criticisms for the brain-based view of addiction?

Answer 18

It disregards human decision making and choice

Addiction is not a disease in the classical sense:

• It’s a group of behaviours, not an illness in its own right
• It can’t be explained by the disease process
• There is no infectious disease or common biological degenerative or neuropathological problem

Question 19

What is tolerance?

Answer 19

The need for increased amounts of the substance to achieve the desired effect

Question 20

What is addiction a product of?

Answer 20

Environmental and physiological factors

Question 21

How does the addiction cycle begin?

Answer 21

Positive reinforcement

Question 22

How does the addiction cycle change over time?

Answer 22

Switches from positive reinforcement to negative reinforcement

Question 23

What disorders contribute to addiction?

Answer 23

Impulsive and compulsive disorders

Question 24

What did George Koob suggest about addiction?

Answer 24

An individual transits from an impulse disorder to a compulsive disorder, there is a shift from positive reinforcement to negative reinforcement

Question 25

What complex connections between brain regions are referred to in relation to reward pathways?

Answer 25

Striatal, midbrain, limbic and prefrontal regions known as the mesocorticolimbic pathways

Question 26

What pathway is made up of the striatal, midbrain, limbic and prefrontal regions?

Answer 26

Mesocorticolimbic

Question 27

Why do we need to talk about "reward systems' with caution?

Answer 27

- Some say the brain have evolved to express dedicated neural systems specifically for encoding reward or pleasure - It is more likely that it has dedicated systems for motivating behaviour (which is positively reinforced) to survive (eg. feeding etc) and drugs interact and compromise these systems

Question 28

Which brain area has elevated dopamine transmission when drugs such as amphetamine, cocaine, nicotine and morphine are taken?

Answer 28

Nucleus accumbens (a region of the ventral striatum heavily innervated by dopamine fibres)

Question 29

What brain region has increased dopamine transmission when eating and having sex?

Answer 29

Nucleus accumbens

Question 30

What receptors are critically involved in long-term potentiation?

Answer 30

NMDA and AMPA

Question 31

What did Wise et al (1995) discover about dopamine levels in the nucleus accumbens in rats?

Answer 31

Dopamine levels in the nucleus accumbens increased during self-administered intravenous cocaine administration in rats

Question 32

How did dopamine antagonists affect lever-pressing behaviour in rats?

Answer 32

Decreased lever-pressing behaviour and lesioning of the nucleus accumbens drastically reduce the rate of drug administration

Question 33

What is Pargyline?

Answer 33

MAO inhibitor and prolongs the actions of 6-OHDA

Question 34

How do dopamine antagonists affect the rewarding effects of drugs?

Answer 34

block the rewarding effects of drugs

Question 35

How is dopamine related to Parkinsons disease?

Answer 35

People with Parkinson's disease are known to have compromised levels of dopamine in the nucleus accumbens and mesollimbic pathways

Question 36

What did patients of parkinson's disease indicate about drugs of abuse?

Answer 36

They report blunted effects of stimulants, which supports the role of dopamine in the rewarding effects of drugs of abuse

Question 37

What is Anhedonia?

Answer 37

Failure to experience rewarding stimuli

Question 38

Lazenberge (2010) argued that, in addition to the dopamine system, the __________ _______ plays a critical role in mediating the experience of _________ evidenced by a voluminous body of ________-________ research.

Answer 38

1. Serotonergic system 2. pleasure 3. depression-related

Question 39

What did Self (2004) report about opiates and GABA?

Answer 39

Reported that opiates increase dopamine in part by removing the inhibitory influence of GABA neurons on dopamine-releasing cells

Question 40

What is gabapentin?

Answer 40

A GABA agonist that has been found to reduce drinking, cravings, improve sleep and affect in participants with alcohol use disorder

Question 41

What changes are associated with addiction?

Answer 41

a) synaptic plasticity b) dendritic size and spines c) changes in white and gray matter d) up/down - regulation of receptors e) changes in intracellular signalling pathways

Question 42

What is long-term potentiation?

Answer 42

Efficiency of neurotransmission and plays a critical role in learning and memory

Question 43

How does cocaine exposure effect long-term potentiation?

Answer 43

Has been found to increase LTP in the ventral tegmental area, lasting for days to months after cessation of treatment

Question 44

How do opioids, cannabis and alcohol effect long-term potentiation?

Answer 44

Been found to elicit LTP in mesolimbic and mesocortical projection areas such as the nucleus accumbens, hippocampus, amygdala and prefrontal cortex

Question 45

What happens to rats during exposure to psychostimulants?

Answer 45

Leads to sensitised locomotor responding to these drugs when rats are re-exposed to the drug weeks-to-months later

Question 46

Repeated exposure to psychostimulants facilitates the acquisition of drug ______-________.

Answer 46

Self-administration

Question 47

What is enhanced by sensitisation in animals?

Answer 47

Subsequent reinstatement of drug-seeking as well as the amount of work animals will produce to self-administer the drug

Question 48

How does sensitisation affect dopamine neurons?

Answer 48

Enhances the excitability of dopamine neurons

Question 49

How do amphetamines change dendrites?

Answer 49

Increased size of dendritic arbours Increased number of spines Elevates number of glutamatergic synapses

Question 50

Where did Robinson et al (2001) find structural changes in neurons in rats that self-administered cocaine?

Answer 50

Neurons in the prefrontal cortex

Question 51

What is gray matter?

Answer 51

Brain tissue containing cell bodies with unmyelinated axons

Question 52

What has research found about gray matter volume and density in substance use disorders including alcohol, nicotine, meth and cocaine?

Answer 52

Reductions in gray matter volume in prefrontal regions and additional mesocorticolimbic structures

Question 53

What have studies shown about gray matter and drug craving?

Answer 53

Drug craving was negatively associated with gray-matter in the insula, prefrontal cortex, amygdala, temporal cortex, occipital cortex, cerebellum and thalamus

Question 54

What is white matter?

Answer 54

Tracks of myelinated axons

Question 55

What did Rivkin et al (2008) report about children who were exposed to cocaine, tobacco, marijuana or alcohol in utero?

Answer 55

They had smaller head circumference and white and grey matter relative to children not exposed to these substances

Question 56

What is CREB?

Answer 56

One of the most studied molecules targetted by cAMP its a protein that plays a key role in learning and memory

Question 57

What is correlated with an increase in phosphorylated CREB?

Answer 57

Diminished sensitivity to drug-induced reward

Question 58

What did Eric Nestler postulate about CREB and drugs?

Answer 58

CREB provides a compensatory mechanism that responds to drugs and that could be linked wth tolerance and with symptoms of dysphoria and withdrawal, but could also play a more general role in signalling the response to stimuli with strong emotional salience

Question 59

What activates CREB?

Answer 59

Morphine treatements in the nucleus accumbens Stressors such as foot-shock and social stress