[Positive and negative reinforcement. Its correction by narcotics].

Achievement of efficacy by a functional system develops subjective sensation, which is necessary to understand the quality of a body's particular system. The mechanisms responsible for positive and negative reinforcement serves this purpose. The involvement of endogenous opioids and dopamine in the telemesencephalic structures in euphoria, dysphoria, and pain is discussed. There is a similarity of the neurophysiology and neurochemistry of positive and negative reinforcements. Craving for drug abuse is associated with the action of functional systems, whose result is the most comfortable emotional state. Some specific features of impact of drug abuse on the mechanisms of positive and negative reward are indicated. It is concluded that psychoactive drug addiction and dependence develop via the natural mechanisms of reinforcement.