Transcript 2920 08
PSYC 2920 Lecture 8 Dependence, Addiction and the Self-Administration of Drugs Factors that Alter the Reinforcing Value of Drugs Other Deprivations and Motivations Hunger Previous Experience with Other Drugs Previous Experience with the Same Drug Physical Dependence Priming Conditioned Reinforcement Second-Order Schedules Conditional tolerance drug seeking vs. taking have dissociable mechanisms Dependence, Addiction and the Self-Administration of Drugs The Neuroanatomy of Motivation and Reinforcement Olds and Milner (1954) Experiment Reinforcement Centers Motivation Control System of the Brain Ventral tegmental area (VTA) Nucleus accumbens Mesolimbic dopamine system Basal ganglia Motor loop Thalamus > cortex > amygdala > hippocampus Learning and memory system Incentive salience Dependence, Addiction and the Self-Administration of Drugs Motivation Control System of the Brain Reward circuitry Reward circuitry continued Dependence, Addiction and the Self-Administration of Drugs The Neuroanatomy of Motivation and Reinforcement “Wanting” Versus “Liking” in Reinforcement “Pleasure Centers” Reinforcing Effects of Drugs Stress and Reinforcement Stress, both present and in the past, increases the strength for reinforcing stimulus. Dependence, Addiction and the Self-Administration of Drugs What Happens During Addiction? Addiction Drugs alter the functioning of the motivation system and the behavior. How? Theory Dependence, Addiction and the Self-Administration of Drugs Incentive Sensitization Theory Drug Craving The desire to experience the effect(s) of a previously experienced psychoactive substance. Robinson & Berridge Motivational aspect (“wanting”) is sensitized while (“liking”) shows tolerance Provides a good explanation strong craving in the absence of dysphoric withdrawal. Provides an explanation for impulsivity Dependence, Addiction and the Self-Administration of Drugs Hedonic Dysregulation and Adaptation Based on physical dependence model Allostatic process Repeated use and/or cessation of use leads to dysphoria, anxiety, depression Set points change if drug use is persistent Hedonic dysregulation Dysphoria Psychological withdrawal Comparing incentive sensitization to Hedonic dysregulation (aka allostasis model) Incentive sensitization impulsivity pure “psychological” addiction cue-associated relapse Positive reinforcement model Hedonic dysregulation Transition from impuslivity to compulsivity Focus on withdrawal Stress-related relapse Negative reinforcement model Dependence, Addiction and the Self-Administration of Drugs Behavioral Economics: Choosing to Use Drugs Based on behavioral mechanisms of positive reinforcement Making choices The Matching Law Animals distribute their resources (time, money, and effort) to different responses in proportion to the density of reinforcement provided by the response. Spiral to Addiction Confound for withdrawal-based explanations? Dependence, Addiction and the Self-Administration of Drugs Behavioral Economics: Choosing to Use Drugs Choice and Time Discounting of delay Perceived value of something decreases the further away it is in time Dependence, Addiction and the Self-Administration of Drugs Behavioral Economics: Price and Demand Inelastic Consumers continue to spend the same amount or more for a drug even though they are not able to purchase as much. Elastic Consumers start spending less for the drug in response to a price increase. Dependence, Addiction and the Self-Administration of Drugs Behavioral Economics: Price and Demand • Demand curves for monkeys responding on FR schedules of 4, 8, 16, 32, 64, and 128 to receive access to a drinking tube that delivered water containing phencyclidine (PCP).