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The cerebral reward-system as a regulatory circuit, habituation and the most common mental disorders in Europe


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Motivational neurons initiate psychovegetative excitation. Appetency, planning and acting is directed by the stimulation of the nucleus accumbens and its inhibitory efferences towards reward. In case of success, a maximal stimulation of the nucleus accumbens causes a maximal release of GABA (and other transmitters), which finally inhibits the motivational neurons and leads to satisfaction. Probably any signal-transduction in the body loses its effect in the event of permanent stimulation („habituation”). The influence of habituation on the regulatory circuit might help to understand many mental and psychosomatic disorders by the loss of effect of dopamine and GABA. The comprehension of the nucleus accumbens as a part of a regulatory circuit leads to surprising conclusions.For example: The model intodruced by this article suggests, that monopolar depression is caused by a disturbance of neurons under the effect of habituation in the regulatory circuit of reward. Bipolar disorder has a completely different pathophysiological background. This article suggests, it should be caused by a disturbance of astrocytes. The model also suggests, that ADHD is not an own syndrome but the infant pattern of (agitated) depression. Other syndromes and symptoms with a possible connection to the model are discussed.
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