British researchers have identified functional connections of the brain that are involved in the formation of drug addiction and resistance to it in the presence of risk factors. For this they conducted a study involving dependent stimulators of volunteers, their brothers and sisters without drug dependence, and people who used drugs, but dependence have not developed. The risk of development of drug was determined by the weakened connections between the sections of the striped body included in the reward system and the prefrontal divisions, and in resistance to dependence connections between them (and motor units) was much stronger. Apparently, in the presence of factors of risk of development of drug resistance to contribute to her coping mechanisms of cognitive control, write the scientists in the Proceedings of the National Academy of Sciences.
Drug addiction is formed by prolonged consumption of substances, a key role is played by the reward system of the brain: after the first few consumptions can form a strong link between the drug and pleasure that it brings consumption, thereby increasing the desire for the reward and, consequently, the frequency of substance use. However, addiction not all people who have ever used drugs — all because in the formation based on its role, in addition to the consumption of the substance are also other factors, both hereditary and environmental factors.
This role, however, is not completely clear — particularly in combination with the very substance use: in other words, it is not clear exactly how the person who is at risk for third-party factors, and consumes drugs, formed dependence, if he can avoid addiction and, if so, what contributes to this.
To understand this question more decided scientists under the leadership of Karen Arse (Karen Ersche) from Cambridge University: they suggested that the resistance to formation of dependence (even in the presence of certain risk factors) may be explained by functional connections between prefrontal departments responsible, inter alia, cognitive control, and reward system of the brain.
To test this, they conducted a study involving 162 volunteers, including, in particular, was drug-addicted people and their siblings with no dependencies. The family history of dependence participants were divided into two groups; in each group, the researchers also identified those who consumed drugs: scientists have only considered a stimulant, although interviewed participants about consumption of cannabinoids is used as a by variable (additionally, participants also provided sociodemographic data and data on consumption of tobacco and alcohol).
Next, the scientists conducted an experiment using fMRI in the resting state, focusing on six areas of the body striped, which refers to the remuneration system: three of these areas are the caudate nucleus, the other three are in a lenticular, as functional in the ways they are linked to different areas of the brain (including the prefrontal departments and motor cortex).
Scientists have discovered that addicts and their relatives nenarcoticeskie observed significantly (p = 0,045) weakened the connection between the ventromedial part of the caudate nucleus, the ventromedial prefrontal cortex and orbitofrontal cortex network, which is involved in the decision-making process for a specific purpose. On the other hand, when resistance to dependence in the presence of family risk factor or consumption of stimulants observed increased (p < 0.05) correlation in the two systems: between the lateral prefrontal cortex and the ventromedial part of the caudate nucleus and between the lenticular nucleus and motor divisions. These relationships, in turn, are responsible for limiting behavioral responses of top-down processes (i.e. inhibition of behaviour).
The authors concluded that the formation of a drug in the presence of risk factors reduced control over the behavior responsible for decision — making, and it concerns even those who do not consume drugs. On the other hand, when resistance to work based on completely different mechanisms: scientists suggest that people at risk, they compensate based on contributing mechanisms, allowing them to more carefully monitor behavioral responses. In the future, the discovered mechanisms can be used in preventive therapy of dependence among people who can be located to it.
According also formed a certain pattern of behaviour that causes a dependent to spend all available resources on the search and consumption of substances: it recently on mice showed that scientists can be broken, for example by introducing new dependent relatives.