PSYCH 2GG3 Lecture Notes - Lecture 6: Drug Delivery, Drug Withdrawal, Reinforcement
Document Summary
Lecture 6 models of abuse and dependence models of abuse and dependence: Addictive drugs are both rewarding and reinforcing (behaviours associated with such drugs tend to be repeated). Tolerance: diminished response to drug administration after repeated use. Withdrawal: at reaching tolerance, physical dependency may occur, withdrawal may be experienced due to a physical dependency, depending on the half-life, withdrawal symptoms can occur within hrs or days. Relief of withdrawal symptoms promotes drug-taking behaviour through negative reinforcement. Progressive-ratio procedure: animals trained to lever-press on a continuous-reinforcement (cr) schedule, animals switched to a low fixed-ratio (fr) schedule, fr-5: 1 drug delivery for every 5 responses, fr is progressively increased until animal stops responding. The breaking point: has to do with when the animal stops working. Initially you start off with a low fixed ratio, then you start to progressively increase it: becomes an even lower schedule, increasing amount of work to get award.
