|Cocaine||Blocks DA uptake||Inc Dopamine||Directly increase dopaminergic transmission in the NAc|
|Heroin||Activates Mu & delta receptors||Inc Dopamine through disinhibition in the VTA of dopamine neurons and direct effects on DA terminals|
|Amphetamines||Inc Dopamine & blocks DA uptake||Inc Dopamine|
|Alcohol||GABA & Substance P||Inc GABA||Increased MDP activity|
|Marijuana||Activates Endocannabinoid receptors||Inc Dopamine in MDP|
|MDMA||Inc Serotonin and block 5-HT uptake||Inc Serotonin||Inc Dopamine|
Extinction: Occurs when a behavior (response) that had previously been reinforced is no longer effective. For example, a rat is first given food many times for lever presses. Then, in "extinction", no food is given. Typically the rat continues to press more and more slowly and eventually stops, at which time lever pressing is said to be "extinguished."
Positive reinforcement (Reinforcement): Occurs when a behavior (response) is followed by a stimulus that is appetitive or rewarding, increasing the frequency of that behavior. In the Skinner box experiment, a stimulus such as food or a sugar solution can be delivered when the rat engages in a target behavior, such as pressing a lever. This procedure is usually called simply reinforcement.
Negative reinforcement (Escape): Occurs when a behavior (response) is followed by the removal of an aversive stimulus, thereby increasing that behavior's frequency. In the Skinner box experiment, negative reinforcement can be a loud noise continuously sounding inside the rat's cage until it engages in the target behavior, such as pressing a lever, upon which the loud noise is removed.
Positive punishment (Punishment) (also called "Punishment by contingent stimulation"): Occurs when a behavior (response) is followed by a stimulus, such as introducing a shock or loud noise, resulting in a decrease in that behavior. Positive punishment is sometimes a confusing term, as it denotes the "addition" of a stimulus or increase in the intensity of a stimulus that is aversive (such as spanking or an electric shock). This procedure is usually called simply punishment.
Negative punishment (Penalty) (also called "Punishment by contingent withdrawal"): Occurs when a behavior (response) is followed by the removal of a stimulus, such as taking away a child's toy following an undesired behavior, resulting in a decrease in that behavior.