Behavioral Neuro - Ch 4 (Addiction)

Addiction

Describe low dose alcohol

stimulates dopamine release via mesocorticolimbic pathway, including reward pathway

When is alcohol a stimulant?

at lower doses

When is alcohol a depressant/sedative?

at higher doses

Describe high dose alcohol

cumulative effects

• enhances GABA_A receptor activity (Increases IPSPs size and receptors are opened longer to have more inhibition)

• reduces NMDA receptor activity (decreases EPSPs size)

What receptors have increased activity during high doses of alcohol?

GABA_A receptors

What receptors have decreased activity during high doses of alcohol?

NMDA receptors

What is binge drinking?

• males: consuming 5 drinks within 2 hours

• females: consuming 4 drink within 2 hours

• legal limit = 0.08 BAC

Define alcohol use disorder according to the DSM-5

problematic pattern of using alcohol the results in impairment in daily life or noticeable distress

Describe the characteristics of the DSM-5 symptoms for AUD?

• loss of control over drinking

• physical dependence

• clinical impairment

Describe positive reinforcement

each alcoholic drink is pleasurable and so increases the probability of future drinking

Which one of these is positive reinforcement

drinking to “feel good”

Describe negative reinforcement

abstinence causes aversive stimulus (negative emotional state of drug withdrawal), so increases the probability of future drinking

What brain regions would you guess are involved in the effects of alcohol?

• dorsolateral prefrontal cortex

• basal ganglia (VTA → NAc)

• extended amygdala

Describe the striatum/nucleus accumbens’ role in alcohol

• reward/incentive salience/binge intoxication

• fewer dopamine receptors (down regulation)

Describe the extended amygdala’s role in alcohol

• negative emotions (e.g. stress, anxiety) leading to withdrawal

• overactivated during withdrawal

  • ex: showing cocaine addicts pictures of things that remind them of cocaine dramatically increases blood flow

Describe the prefrontal cortex’s role in alcohol

• executive function (attention and higher cognition) deficits/craving

• overactivated during craving

  • ex: interviewing cocaine addicts about their drug use dramatically increases blood flow

During the progression of AUD, the _________ is involved in anticipation and preoccupation of the next drink.

prefrontal cortex

Which drug is used by a greater percentage of adolescents than adults?

Marijuana

How does alcohol alter neurotransmission?

it enhances GABA receptor activity

What changes does the striatum undergo in the brains of addicted individuals?

dopamine receptors decrease

The transition from causal drinking to alcohol dependence is marked by a change from _______ to _________ as a motivation for drinking

Positive reinforcement; negative reinforcement

What is the brain region that is associated with the preoccupation and cravings symptoms of a person with substance use disorder

prefrontal cortex

2 neurotransmitter receptors that alcohol directly effects

GABA_A and NMDA

What happens in the amygdala once a person has developed a SUD?

Increased activation when the person is thinking about the drug of abuse (or related things)