2A. Drugs and the Brain’s Reward Circuits Flashcards
drugs that influence subjective experience and behavior by acting on the nervous system
psychoactive drugs
releases dopamine into target regions in response to rewarding stimuli, causing a sense of pleasure and reinforcing associated behavior
ventral tegmental area (VTA)
evaluates the motivational value of stimuli by integrating information from different brain regions
nucleus accumbens
regulates impulses, decision-making, and modulates the activity of the VTA and nucleus accumbens
prefrontal cortex
enables communication between the various components of the reward circuit
medial forebrain bundle
drugs of abuse hijack the normal functioning of the reward circuit by causing an excessive release of ___, leading to neuroadaptations and addictive behaviors
dopamine
preferred route of administration; dissolve in the fluids of the stomach; takes place sooner; easy and safer
oral ingestion
preferred by drug-addict persons; strong, fast and predictable effect; bloodstream delivers the drug directly to the brain
injection
absorbed into the bloodstream through the rich network of capillaries in the lungs
inhalation
administered through the mucous membranes of the nose, mouth and rectum.
absorption through mucous membranes
drugs enters bloodstream - carried to the blood vessels of the ___
CNS
makes it difficult for potentially dangerous bloodborne-chemicals to pass into the extracellular space across CNS neurons and glia
blood-brain barrier
eliminates a drug’s ability to pass through lipid membranes of cells so that i can no longer penetrate the blood-brain barrier
drug metabolism
state of decreased sensitivity to a drug that develops as a result of exposure to it; less effect than it had before
tolerance
one drug can produce tolerance to other drugs that act by the same mechanism
cross tolerance
increasing sensitivity to a drug
drug sensitization
drug tolerance that results from changes that reduce the amount of the drug getting to its sites of action
metabolic tolerance
drug tolerance that results from changes that reduce the reactivity of the sites of action to the drug
functional tolerance
after significant amounts of a drug have been in the body for a period of time (e.g., several days), its sudden elimination can trigger an adverse physiological reaction
withdrawal syndrome
individuals who suffer withdrawal reactions when they stop taking a drug and said to be physically dependent on that drug
physically dependent
habitual drug use despite its adverse effects on health and social life and despite their repeated efforts to stop using it
drug adddiction
type of addiction that involves psychotropic drugs
substance addiction
type of addiction
that involves pathological gambling, video games, internet addiction (compulsive cybersex, excessive online shopping)
behavioral aaddiction
excessive involvement in work
workaholism
conditional stimuli that repeatedly predict the effects of a drug come to elicit greater and greater conditioned compensatory responses
conditioned compensatory responses
external, public stimuli such as the drug-administration environment as the conditional stimuli
exteroceptive stimuli
internal, private stimuli (ex. thinking about a drug can evoke conditioned compensatory responses)
interoceptive stimuli
five commonly used drugs
- nicotine
- alcohol
- marijuana
- cocaine and other stimulants
- opioids (heroin and morphine)
three stages in the development of an addiction
- initial drug taking
- habitual drug taking
- drug craving and repeated relapse
factors for addiction
- genetic vulnerabilities
- epigenetic vulnerabilities
