Reinforcement Flashcards
Homeostatic modulation theory
Drug use maintained to reset biological mechanisms. Focus on physiological adaptation. Not the full story, part of the whole.
Physical adaptation
Bio changes to compensate for repeated drug exposure. Change is long term but can be reversed. Not all drugs create physical dependence, it doesn’t explain initiation or relapse after withdrawal.
Abuse liability paradigm
Positive reinforcement. Put a rat in a box with a lever that gives the drug. Measure amount of lever presses. Can measure impacts of bio treatment to minimise addiction.
Brain stimulation in dopamine pathway
Rats in a lever box. Delivers direct brain stimulation. Pressed lever more when electrode was in the VTA/NACC. High responses to activation in the mesolimbic pathway.
Damage to DA/mesolimbic
Damage decreases response to drugs. Rats trained to lever press for cocaine. Surgery to damage pathway, surgery with no effect or saline. Damage decreases use at the same rate as saline.
Prediction errors
The difference between expected and actual reward. Rats taught to predict reward. Show more response when reward is unexpected, pathway becomes more active. When expected and not received firing falls below baseline.
NACC subdivisions
Mesoventral medial (shell) mesoventral lateral (core).
Structurally distinct regions with different inputs and outputs. Few afferent/outgoing signals are limited to one region. Efferent/incoming signals tend to be contained.
They process info similarly but different roles of behaviour.
Animal drug us in shell/core
Animals will self administer drugs into the shell but not the core. The core seems linked to cue response, when lesioned cue responses stop.
Opponent process model
Process A is the initial strong affective reaction and activated process B which is the opposing affective response. Processes combine to create experienced hedonic response. B has a slow build up and decline.
Prolonged use builds up B process so starts earlier and is stronger. Baseline falls until process A only returns to baseline without a high.
Pet competitive binding procedure
2 scan sessions.
Baseline) single injection tracer to access binding potential
Challenge) neurotransmitter system is disrupted with pharmacological challenge.
Differences in binding potential are taken to reflect levels of endogenous NT.
Davies 1997
Language choices of addicts
Addiction isn’t real, addicts choose language based on who they’re around. Around medical or police they use words suggesting lack of control and blame. Around friends and peers they express preference.
X could be a cover from friends not professionals. Addiction carries stigma.
Becker/Murphy 1988
Theory of rational addiction
Benefit/cost is context dependant. £100 is worth more to poor people than rich. Addiction increases consumption of a drug as to them there is more benefit, addicts respond to permanent more than temporary increases in cost as they have a larger impact.
Is supported by contingency management.
Expectancy theory
Users expectancy influences the effect of a drug. If they expect to struggle with abstinence they will. But it’s not a concrete concept. Specific role is unclear. Expectancies aren’t just beliefs, some see them as memory structures or a pathway other factors can influence.
Cognitive bias theory
An extension of expectancy theory. Is a bias in belief, attention and memory. Linked to beliefs that are the root of addiction. Loss of control is explained by automatic preconscious cue processing of stimuli. Drug cues are evaluated preattentively and prioritised, trigger responses.
Stages of behaviour change
Precontemplation, contemplation, preparation, action and maintenance.
