Alcohol spoils the reward system
Scientists from the Higher School of Economics, the Higher Normal School (Paris), Indiana University and the Nizhny Novgorod Institute of Applied Physics of the Russian Academy of Sciences have found out exactly how alcohol disrupts the work of dopamine receptors.
Neurotransmitter dopamine is a biologically active chemical that affects the "satisfaction center" in the brain, causing either a feeling of anticipation of pleasure from an action, or pleasure itself if a pleasant event occurs unexpectedly. The "reinforcing" property of dopamine contributes to the repeatability of "favorable" actions. If the pleasure turned out to be less than expected, or an unpleasant event occurred, then the amount of dopamine released decreases significantly, which leads to "disappointment" and unwillingness to repeat the action that led to this.
Biologists used a biophysical model of dopaminergic neurons (those that secrete dopamine) and described a mode of operation called an "error signal".
Dopaminergic neurons secrete different amounts of dopamine, depending on whether a person got what he wanted as a result of his actions or could not achieve what he wanted. The difference between the amount of dopamine that is released when everything worked out, and the one that is released if the result is disappointing, and was called an "error signal". This signal should encourage you to do "useful" things and, conversely, prevent you from doing "harmful" ones.
Scientists have found that alcohol can change the work of neurons. Under its influence, dopaminergic neurons transmit alcohol-related stimuli as "useful", regardless of whether they coincide with the expected result or not. Without the influence of alcohol, these neurons would transmit a measure of correspondence between the expected and received reinforcement, preventing the commission of "harmful" actions.
Due to the fact that stimuli under the influence of alcohol cause a large production of dopamine, the range of possible behavioral reactions narrows in a chronic alcoholic and he begins to look for the possibility of drinking alcohol. Either he is not aware of the consequences of his actions, or he is aware, but this practically does not affect his behavior. In order to correctly assess the consequences of their actions, it is necessary that dopaminergic neurons transmit an error signal, providing negative reinforcement of negative actions, but this does not happen when alcohol affects dopaminergic neurons, disrupting the work of the reward system.
Perhaps if scientists can "make" dopamine work in a balanced way, correctly respond to stimuli in the environment in the presence of alcohol in the body, showing the difference between what you expect and what you get, then science will be able to help people suffering from alcohol addiction.
The study is described in the journal PLOS (Morozova et al., Dopamine Neurons Change the Type of Excitability in Response to Stimulation).
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10.03.2017