Neuro and Behavior of Addiction Flashcards
Dependence definition
repeated, compulsive use of a drug.
Cross-dependence definition
drugs within a pharmacological class can support individuals physically dependent on other drugs in the same class
Tolerance definition
Reduced drug effect with repeated use & a need for higher doses to produce the same effect
Drug Addiction definition
Extreme form of dependence in which the need to obtain and consume the drug becomes the dominant force in an individual’s life.
Druge Abuse definition
Continuous use of a drug in a way that deviates from the social norms of a given culture; disregard of harmful medical or social consequences.
Withdrawal definition
Pathophysiologic disturbance experienced as a result of withdrawal of a drug that had induced dependence
Acute rewarding effects of drugs of abuse (binge/intoxication) are mediated by
neurochemical elements such as dopamine and opioid peptides in the nucleus accumbens and amygdala
Acute withdrawal from all major drugs of abuse produces
increases in reward thresholds, increases in anxiety-like responses and increases in CRF in the amygdala that are of motivational significance
Compulsive drug use associated with dependence is mediated by
loss of function of reward systems but recruitment of brain stress systems such as corticotropin releasing factor, norepinephrine and dynorphin in the extended amygdala
Acute drug administration leads to increased ____ release in ____ and is associated with subjective descriptors of reward
dopamine; striatum
Extended Amygdala integrates what two systems?
brain arousal system and hedonic processing system; promotes negative reinforcement assoc. with addiction
Extended Amygdala is comprised of what?
afferents from basolateral amygdala and hippocampus
efferents to medial ventral palladium and lateral hypothalamus
what brain structure plays a key role in fear conditioning and the emotional component of pain?
amygdala
Neuroadaptation to chronic drug exposure?
decreased functioning of NT systems that the drug induces. i.e. a decrease in the number of receptors leading to tolerance
Neuroadaptation that leads to withdrawal associated with fatigue, decreased mood and psychomotor retardation
linked to reduced dopamine (mesolimbic) and 5- HT (nucleus accumbens)
Neuroadaptation as it relates to dynorphin?
Dynorphin via kappa opioid receptors (up-regulated after drug use) acts as a negative feedback regulating dopamine action, thus is antihedonic
Largest hurdle in breaking addiction cycle?
influence of drugs on executive function leads to enhanced sensitivity to conditioned cues
Describe the KOPr / dynorphin tone relationship with addiction cycle
** possible exam material
- Initial experimentation causes a surge in dopamine, leads to compensatory inhibition by increased KOPr / Dynorphin tone.
- In absence or withdrawal of drugs, KOPr / Dynorphin tone still elevated, leading to anhedonia and depression
- re-escalation/relapse is exacerbated by learnt behavior patterns and pre-existing up-regulation of KOPr / Dynorphin tone
Processing of conditioned reinforcement occurs where?
basolateral amygdala
Contextual information is processed where?
hippocampus
PFC and basolateral amygdala project to the ventral striatum in what process using what NT?
preoccupation, anticipation, craving
glutamatergic (glutamate)
Sensitization definition and example
Repeated use of the same drug elicits an escalating effect
bruxism, tics
Cloninger type I alcoholic description
Type I individuals alcoholism generally occurred later in life, affected more by environment and influenced more by harm avoidance.
Cloninger type II alcoholic description
Type II alcoholism occurs earlier in life, usually children of alcoholics who are guided by novelty seeking
Three general stages of addiction going from impulsivity to compulsivity
binge/intoxication, withdrawal/negative affect, and preoccupation/anticipation.
In late stage of addiction, what is the driving force to continue abusing a substance?
negative reinforcement (compulsivity, withdrawal symptoms etc)
In early stage of addiction, what is the driving force to continue abusing a substance?
positive reinforcement (impulsivity, pleasure from drug, etc)
Rats will self-administer cocaine directly into what part(s) of the brain to activate the reward pathway
nucleus accumbens (or the VTA)
Explain synergism in drug use
use of alcohol or “recreational drugs” to enhance effects of food, music, sex, etc. can “synergize” to enhance enjoyment of one another.
Drug-induced reinstatement is localized to _____ parts of the brain and is mediated by the neurotransmitter ____?
medial prefrontal cortex, nucleus accumbens, ventral pallidum circuit
glutamate
Cue-induced reinstatement is localized to _____ parts of the brain and is mediated by the neurotransmitter _____?
basolateral amygdala
dopamine
Craving type II involves stress and involves what circuit?
HPA axis
Bruxism and tics secondary to stimulant abuse are examples of
** Possible exam question
Sensitization
Are Cloninger Type II alcoholics novelty seeking or harm avoiding? Does addiction occur in early or late life?
novelty seeking and early life
Alcohol Anonymous philosophy “change people, places and thing” refers to?
Stimuli paired with drug craving
The area of brain that serves in emotional processing and is activated for cue vs. drug induced craving is?
Amygdala
The components of reward pathway include?
Prefrontal cortex, nucleus accumbens, VTA
