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Negative Reinforcement
An increase in behavior that removes or reduces an aversive stimulus
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Naloxone
Drug that blocks opiate receptors; antagonizes the reinforcing effects of opiates.
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Antagonist-Precipitated Withdrawal
Sudden withdrawal from a drug caused by a technique of blocking the effects with an antagonist.
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Appetitive Stimulus
Something the organism will approach.When a behavior is regularly followed by this, causes positive reinforcement.
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Drug Dependency
Factors are the positive reinforcement and the speed of the effects-Drugs with more immediate effects are more addictive
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NAC
Important role in reinforcement, all addictive drugs that produce positive reinforcement stimulate dopamine release in the NAC.
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Instrumental Conditioning
Nueral changes begin in the VTA and NAC eventually involve the dorsal striatum which is critical in intrumental conditioning.
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Craving
The urge to take a drug to which it becomes addictive; cannot be explained by withdrawal symptoms.
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Reinstatement
vmPFC plays an inhibitory role in reinstatement, dACC plays a facilitatory role.
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ACC, OFC, Insula, Dorsolateral Prefrontal Cortex.
Cravings for appetizing food increases activity in these.
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Schizophrenia
Higher proportion of drug addicts than general population
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Opiates
produce analgesia, hypothermia, sedation, and reinforcement.
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Endogenous Opioids
May play a role in the reinforcing a effects of stimuli such as water or addictive drugs.
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Cocaine
- Inhibits the reuptake of dopamine by terminal buttons.
- Reinforcing effects mediated by increase dopamine in NAC. Symptoms of alertness, activation, and psychotic like paranoid schizo.
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Amphetamines
Causes the dopamine transporters in terminal buttons to run in reverse, releasing dopamine from terminal buttons. Reinforcing effects mediated by dopamine in NAC.
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Methamphetamines
Chronic abuse associated with reduced number of dopaminergic axons & terminals in the striatum which may be involved in the development of hypofrontality.
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Nicotine
Stimulates the release of mesolimbic dopaminergic neurons. Smoking excites nioctinic acetylcholine receptors and also desensitizes them leading to withdrawal.
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Insula & Nicotine
Damage to the Insula is associated with the cessation to smoking which can lead to weight gain b/c nicotine releases GABA in the hypothalamus which decreases activity of MCH neurons which reduce food intake.
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Alcohol During Development
Exposure causes neural destruction through apoptosis.
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Alcohol
- Has positive reinforcing effects and through anxiolytic action, has negative reinfocring effects.
- Indirect antagonist at NMDA receptors
- Indirect agonist at GABA receptors
- Stimulates dopamine release in NAC
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Alcohol Withdrawal
Can lead to seizures caused by compensatory upregulation of NMDA receptors.
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Alcohol Cravings
endogenous opioids plays a role in reinforcement, increase in number of u opiate receptors during abstinence intensify cravings
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Cannabis/THC
- Stimulates release of dopamine in NAC.
- CB1 receptor is responsible for effects of THC.
- Produces memory deficits by acting on inhibitory GABAergic neurons.
- Its been indicated that cannabis use is associated with incidence of Schizophrenia
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CB1 receptor
- When mutated there is a reduced reinforcing effect of alcohol, cocaine, and opiates and cannabinoids.
- Blocking reduces nicotine effects.
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Heredity and Drug Abuse
- Most ppl exposed to addictive drugs dont become addicts.
- Likelihood is strongly effected by heredity.
- Ex. variations in alcohol dehydrogenase, u opiate, GABA, and acetylcholine receptors involved in susceptibility to alcoholism.
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Methadone Maintenance
Replaces addiction to heroin by addiction to a opiate that does not make a euphoric effect.
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Buprenorphine
Partial agonist for u opiate receptors reduces crazings for opiates and isnt of interest to opiate addicts especially combined with naltrexone.
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GVG (gamma-vinyl GABA)
Promising for Cocaine addiction.
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Rimonabant
CB1 receptor antagonist aids in quiting smoking and reduces the likelihood of weight gain.
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Buproprion
An antidepressant drug; shown to help smokers stop their habit.
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Varenicline
Partial Agonist for the nicotinic receptor is one of the more effective possibly for smoking.
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Naltrexone
- An opiate receptor blocker that is the most effective adjunct treatment for alcoholism as it reduces the its reinforcing effects.
- Addition of Acamprosate (NMDA receptor antagonist) helps facilitate these effects.
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