BIOPSYCH 0505 Edition 1nd Lecture 16 Outline of Last Lecture Addictions and reinforcements I II III Intracranial Self Stimulation A Olsen and Miller professor and student B Neal Miller Rewarding Effects of Drugs A Positive reinforcement B Negative reinforcement C Dose response curve Tolerance A Tolerance B What causes the decrease in tolerance C Metabolic tolerance D Functional tolerance E Segale F Conditioned tolerance Outline of Current Lecture I Theories of Addiction A Physical dependence theory B Positive incentive theory C Incentive sensitization theory II What makes addicts addicted A Mesotelencephalic dopamine system B Nucleus subcombance C Mapping studies D Lesion studies E Antagonist studies 1 Dopamine antagonists decrease ICSS F Agonist studies 1 Dopamine agonists increase ICSS Current Lecture I Theories of Addiction individual who is addicted and cannot stop using the drug even though the drug is causing serious physical financial and social problems These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute A Physical dependence theory 1 Negative withdrawal symptoms as the drug acts as a negative reinforcement 2 Once the individual is addicted the chance that withdrawal symptoms will occur is increased people become trapped in the cycle 3 Detox takes several days so the body can adjust and heal 4 Cocaine victims do not go through withdrawal B Positive incentive theory 1 Users will take the drugs for the positive effects of the drug 2 Addiction is more likely because it gives the body positive reinforcement 3 Tolerance to the aversive effects of the drug and the users pleasure might increase in which the body is getting some kind of reward No tolerance with cocaine C Incentive sensitization theory 1 Pleasurable response begins to decrease tolerance 2 People continue to take the drug and then say they want to stop because it s not as fun anymore 3 Individuals engage in addictive drug behavior for two reasons a It produces a positive effect then creates a wanting craving that leads to more drug taking behavior b It produces a positive effect that eventually decreases yet it it creates a very strong craving that increases II What makes addicts addicted A Mesotelencephalic dopamine system 1 Part of the motor system that leads to the repetitive behaviors 2 Dopamine neurons project from the mesencephalon into different regions of the telencephalon 3 The cell bodies are in two midbrain nuclei the substantia nigra axons sent to the dorsal striatum or nigrostriatal pathway and the ventral tegmental area axons sent to limbic and cortical cites 4 Mesolimbic pathway is connected to the wanting and craving terminating in the frontal lobe B Nucleus subcombance is essential for the ICSS intracranial self stimulation C Mapping studies areas that support ICSS are typically part of the mesotelencephalic dopamine system D Lesion studies chemical lesion when 6 HD toxin only for dopamine and will not effect any other neuron disrupts ICSS 1 Dopamine if a major player because there is a reduction in ICSS behaviors E Antagonist studies 1 Dopamine antagonists decrease ICSS haloperidol and spiroperidol 2 Reduced the lever pressing behavior in rats for cocaine and morpheme food and water F Agonist studies 1 Dopamine agonists increase ICSS cocaine and amphetamine 2 Reinforced it even more and increased the lever pressing behavior and the rats over ate and over drank
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