yuhuu magang mode on (about reward system)
Reward system
From Wikipedia, the free encyclopedia
In neuroscience, the reward system is a collection of brain structures which attempts to regulate and control behavior by inducing pleasurable effects.
Psychological reward
A psychological reward is a process that reinforces behavior — something that, when offered, causes a behavior to increase in intensity. Reward is an operational concept for describing the positive value an individual ascribes to an object, behavioral act or an internal physical state. Natural rewards include those that are necessary for the survival of species, such as eating, drinking, sex, and fighting.[1]
Secondary rewards derive their value from the primary reward, and include shelter, money, pleasant touch, beauty, music, etc. The functions of rewards are based directly on the modification of behavior and indirectly on the sensory properties of rewards. For instance, altruism may induce a larger psychological reward, although it doesn't cause sensations. Rewards are generally considered more effective than punishment in enforcing positive behavior.
Rewards induce learning, approach behavior and feelings of positive emotions.
Anatomy
The major neurochemical pathway of the reward system in the brain involves the mesolimbic and mesocortical pathway. Of these pathways, the mesolimbic pathway probably plays the major role, and goes from the ventral tegmental area via the medial forebrain bundle to nucleus accumbens, where dopamine is primarily released. This acts on D3 receptors to inhibit the production of cAMP.
Modulation by drugs
Main article: Drug addiction
Almost all drugs causing drug addiction increase the dopamine release in the mesolimbic pathway, e.g. opioids, nicotine, amphetamine, ethanol and cocaine. After prolonged use, psychological drug tolerance and sensitization arises.
Psychological drug tolerance
The reward system is partly responsible for the psychological part of drug tolerance. One explanation of this is a sustained activation of the CREB protein, causing a larger dose to be needed to reach the same effect.
Sensitization
Sensitization is an increase in the user's sensitivity to the effects of the substance, counter to the effects of CREB. A transcription factor, known as delta FosB, is thought to be involved by activating genes that causes sensitization. The hypersensitivity that it causes is thought to be responsible for the intense cravings associated with drug addiction, and is often extended to even the peripheral cues of drug use, such as related behaviors or the sight of drug paraphernalia.
From Wikipedia, the free encyclopedia
In neuroscience, the reward system is a collection of brain structures which attempts to regulate and control behavior by inducing pleasurable effects.
Psychological reward
A psychological reward is a process that reinforces behavior — something that, when offered, causes a behavior to increase in intensity. Reward is an operational concept for describing the positive value an individual ascribes to an object, behavioral act or an internal physical state. Natural rewards include those that are necessary for the survival of species, such as eating, drinking, sex, and fighting.[1]
Secondary rewards derive their value from the primary reward, and include shelter, money, pleasant touch, beauty, music, etc. The functions of rewards are based directly on the modification of behavior and indirectly on the sensory properties of rewards. For instance, altruism may induce a larger psychological reward, although it doesn't cause sensations. Rewards are generally considered more effective than punishment in enforcing positive behavior.
Rewards induce learning, approach behavior and feelings of positive emotions.
Anatomy
The major neurochemical pathway of the reward system in the brain involves the mesolimbic and mesocortical pathway. Of these pathways, the mesolimbic pathway probably plays the major role, and goes from the ventral tegmental area via the medial forebrain bundle to nucleus accumbens, where dopamine is primarily released. This acts on D3 receptors to inhibit the production of cAMP.
Modulation by drugs
Main article: Drug addiction
Almost all drugs causing drug addiction increase the dopamine release in the mesolimbic pathway, e.g. opioids, nicotine, amphetamine, ethanol and cocaine. After prolonged use, psychological drug tolerance and sensitization arises.
Psychological drug tolerance
The reward system is partly responsible for the psychological part of drug tolerance. One explanation of this is a sustained activation of the CREB protein, causing a larger dose to be needed to reach the same effect.
Sensitization
Sensitization is an increase in the user's sensitivity to the effects of the substance, counter to the effects of CREB. A transcription factor, known as delta FosB, is thought to be involved by activating genes that causes sensitization. The hypersensitivity that it causes is thought to be responsible for the intense cravings associated with drug addiction, and is often extended to even the peripheral cues of drug use, such as related behaviors or the sight of drug paraphernalia.
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